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CDC Prevention Guidelines Database (Archive)


Warning:

This online archive of the CDC Prevention Guidelines Database is being maintained for historical purposes, and has had no new entries since October 1998. To find more recent guidelines, please visit the following:
  • MMWR at http://www.cdc.gov/mmwr/mmwrsrch.htm
  • CDC Web Search at http://www.cdc.gov/search.do


Hospital Infections Program NOTE: Guidelines for Prevention of Intravascular Device-Related Infections is currently being updated Draft version was pubished for comment in the Federal Register on 9/27/95. Final publication should be available in the near future.

Department of Health and Human Services, Center for Disease Control and Prevention, National Center for Infectious Diseases, Hospital Infections Program

Publication date: 08/01/1991


Table of Contents

CDC Guidelines coordinated by the Hospital Infections Program

CDC Guidelines for the Prevention and Control of Noscomial Infection

Construction, Renovation, and Ventilation

How to Order Guidelines

Guideline for Prevention of Intravascular Infections

Guideline for Prevention of Noscomial Pneumonia

Guideline for Isolation Precautions in Hospitals

HIV Topics

Universal Precautions

Protective Barriers

Written Guidelines - Universal Precautions

Sterilization, Disinfection, Decontamination of Patient-Care Equipment

Laundry

Disinfection, Sterilization, Decontamination Publications

Surveillance Summary

Management of Exposures

Infection Control in Dental Practice

Guidelines for Prevention of Transmission of HIV to Health-Care and Public Safety Workers

AZT Post-Exposure use, General Information

AZT Dose Schedules after Occupational Exposure to HIV

AZT Toxicity

AZT Studies

Prevention of Tuberculosis Transmission Involving HIV-Infected Patients.

Aerosols and HIV

Sterilization, Disinfection, and Laundry

Laundry

Medical Waste

Methicillin-Resistant Staphylococcus Aureus

Control of MRSA Outbreak

National Noscomial Infection Surveillance Rates and Definitions

National Rates of Noscomail Infections

Joining NNIS

CDC Definitions

Long-Term Care Facilities

Infection Control Courses

POINT OF CONTACT FOR THIS DOCUMENT:


CDC Guidelines coordinated by the Hospital Infections Program

The following information has been prepared by CDC medical epidemiologists and is designed to answer questions on infection control frequently asked by health care workers, including infection control practitioners, AIDS coordinators, and state or local health officials


CDC Guidelines for the Prevention and Control of Noscomial Infection

The "CDC Guidelines for the Prevention and Control of Nosocomial Infections" is a set of 7 reports on different aspects of hospital infection control. Five reports are current or updated, namely, those on catheter-associated urinary tract and surgical wound infections, isolation precautions in hospitals, infection control in hospital personnel, and handwashing and hospital environmental control.

Two reports are scheduled for revision, namely, those on prevention of intravascular infections, and prevention of nosocomial pneumonia. Suggested references are given for these guidelines under revision.

The CDC Guidelines do not address the issue of efficacy or safety of medical products or devices, nor do they give standards for perinatal care, or for construction, renovation, or ventilation of health-care facilities.

Answers concerning these questions may be found by contacting the following sources:


Construction, Renovation, and Ventilation

The American Institute of Architects, Committee on Architecture for Health, with assistance from the U.S. Department of Health and Human Services, published in 1987 the newest edition of the "Guidelines for Construction and Equipment of Hospital and Medical Facilities". This document contains information on model standards for construction, ventilation, and equipping new medical facilities. It can be purchased from the American Institute of Architecture Bookstore by calling telephone number 1-800-242-4140, or by writing to the:

How to Order Guidelines

Because of limited resources, CDC cannot provide users with copies of the Guidelines, nor can it maintain a continuing list of persons interested in receiving information.

There are two sources for all or some of the CDC Guidelines:

National Technical Information Service Address:

National Technical Information Service or NTIS
5285 Port Royal Road
Springfield, Virginia 22161
Telephone : (703) 487-4650

Publication Numbers --

To facilitate ordering from the NTIS, here are the publication numbers of the guidelines: All the guidelines begin with the same first two letters: "P" as in Paul, and "B" as in boy. The complete set of "CDC Guidelines for the Prevention and Control of Nosocomial Infections" is publication No. PB86-133022.

Each individual report has its own number:

Government Printing Office --

Two guidelines, the "CDC Guideline for Isolation Precautions in Hospitals" and the "CDC Guideline for Infection Control in Hospital Personnel," may be purchased as a combined document from an additional source:
U.S. Government Printing Office
Telephone 202-783-3238
The order number for the document is 017-023-00148-5.

Instruction Cards --

The Instruction Cards for the "CDC Guideline for Isolation Precautions in Hospitals" are not available from the CDC or any other government agency. They are offered for sale by private companies that advertise in infection control journals and through direct mail. You may also wish to contact a local printer and have cards made to your own specifications.


Guideline for Prevention of Intravascular Infections

The "Guideline for Prevention of Intravascular Infections" is currently being updated. Some of the issues being addressed in the Guideline revision include: appropriate intervals for changing peripheral intravenous (IV) tubing and IV site dressing, and management of central lines. The availability of the newly revised Guideline will be announced in the Morbidity and Mortality Weekly Report and in infection control publications. Until a revision is available, however, you are advised to review information from reliable sources such as reports published in scientific journals, presented at scientific meetings, or documented by manufacturers, about certain recommendations for infection control.

Some suggested references include:


Guideline for Prevention of Noscomial Pneumonia

A revision of the "Guideline for Prevention of Nosocomial Pneumonia" is anticipated. In the meantime, it is advisable to review information about specific infection control recommendations from reliable, more recent sources such as reports published in scientific journals, presented at scientific meetings, or documented by manufacturers. The following references may be useful to you:


Guideline for Isolation Precautions in Hospitals

Since its publication in 1983, the "Guideline for Isolation Precautions in Hospitals" has been updated by 2 documents which recommend the use of universal precautions to prevent transmission of bloodborne pathogens in health-care settings. The first document, "Recommendations for Prevention of HIV Transmission in Health-Care Settings", was published on August 21, 1987, as a supplement to the Morbidity and Mortality Weekly Report. The second document, "Update: Universal Precautions for Prevention of Transmission of HIV, Hepatitis B Virus, and Other Bloodborne Pathogens in Health-Care Settings," was published in the Morbidity and Mortality Weekly Report on June 24, 1988. These 2 documents may be obtained by calling the AIDS Hotline 1-800-342-2437 or the National AIDS Information Clearinghouse at 1-800-458-5231.


HIV Topics

The following information applies to the Human Immunodeficiency Virus or HIV related topics. For information about the Occupational Safety and Health Administration (OSHA) proposed rule on occupational exposure to bloodborne pathogens, call 202-523-7157.


Universal Precautions

"Universal blood and body-fluid precautions" or "universal precautions" as defined by CDC, refer to a set of precautions designed to prevent transmission of human immunodeficiency virus (HIV), hepatitis B virus (HBV), and other bloodborne pathogens in health-care settings. Under universal precautions, blood and certain body fluids of all patients are considered potentially infectious for HIV, HBV and other bloodborne pathogens.

Universal precautions take the place of and eliminate the need for the isolation category "Blood and Body Fluid Precautions" in the 1983 CDC Guidelines for Isolation Precautions in Hospitals. However, implementing universal precautions does not eliminate the need for other category- or disease-specific isolation precautions, such as enteric precautions for infectious diarrhea, AFB isolation for pulmonary tuberculosis, or contact isolation for Methicillin-Resistant Staphylococcus aureus.

Universal precautions differ from the system of Body Substance Isolation or BSI used in some institutions. For information about BSI, refer to the following articles:

  1. "Rethinking the role of isolation precautions in the prevention of nosocomial infections," published in the Annals of Internal Medicine, 1987, Volume 107, pages 243-246, and:
  2. "Implementing and evaluating a system of generic infection precautions: Body substance isolation," published in the American Journal of Infection Control, February 1990, Volume 18, pages 1-12.
Universal precautions apply to blood, other body fluids containing visible blood, semen, and vaginal secretions. Universal precautions also apply to tissues and to the following fluids: cerebrospinal, synovial, pleural, peritoneal, pericardial, and amniotic fluids. Universal precautions do not apply to feces, nasal secretions, sputum, sweat, tears, urine, and vomitus unless they contain visible blood. Universal precautions do not apply to saliva except when visibly contaminated with blood or in the dental setting where blood contamination of saliva is predictable.

Universal precautions involve the use of protective barriers such as gloves, gowns, aprons, masks or protective eyewear, which can reduce the risk of exposure of the health-care worker's skin or mucous membranes to potentially infective materials.

In addition, under universal precautions, it is recommended that all health-care workers take precautions to prevent injuries caused by needles, scalpels and other sharp instruments or devices.

Pregnant health-care workers are not known to be at greater risk of contracting HIV infection than health-care workers who are not pregnant; however, if a health-care worker develops HIV infection during pregnancy, the infant is at risk of infection resulting from perinatal transmission. Because of this risk, pregnant health-care workers should be especially familiar with, and strictly adhere to, precautions to minimize the risk of HIV transmission.

For information about the Occupational Safety and Health Administration (OSHA) proposed rule on occupational exposure to bloodborne pathogens, call 202-523-7157.


Protective Barriers

All health-care workers should routinely use appropriate barrier precautions to prevent skin and mucous-membrane exposure during contact with any patient's blood or body fluids that require universal precautions. Recommendations for the use of gloves are presented in detail in the Morbidity and Mortality Weekly Report dated June 24, 1988, which is available by calling the National AIDS Information Hotline at 1-800-342-2437 or the National AIDS Information Clearinghouse at 1-800-458-5231.

Gloves should be worn:

Gloves should be changed after contact with each patient.

Hands and other skin surfaces should be washed immediately or as soon as patient safety permits, if contaminated with blood or body fluids requiring universal precautions. Hands should be washed immediately after gloves are removed.

Gloves should reduce the incidence of blood contamination of hands during phlebotomy, but they cannot prevent penetrating injuries caused by needles or other sharp instruments.

Institutions that judge routine gloving for all phlebotomies is not necessary, should periodically reevaluate their policy. Gloves should always be available to health-care workers who wish to use them for phlebotomy. In addition, the following general guidelines apply:

  1. Use gloves for performing phlebotomy when the health-care worker has cuts, scratches, or other breaks in his/her skin.
  2. Use gloves in situations where the health-care worker judges that hand contamination with blood may occur, for example, when performing phlebotomy on an uncooperative patient.
  3. Use gloves for performing finger and/or heel sticks on infants and children.
  4. Use gloves when persons are receiving training in phlebotomy.
The Center for Devices and Radiological Health, FDA, has responsibility for regulating the medical glove industry. For more information about selection of gloves, call FDA at (301) 427-1060.

Masks and protective eyewear or face shields should be worn by health-care workers to prevent exposure of mucous membranes of the mouth, nose, and eyes during procedures that are likely to generate droplets of blood or body fluids requiring universal precautions. Gowns or aprons should be worn during procedures that are likely to generate splashes of blood or body fluids requiring universal precautions.

All health-care workers should take precautions to prevent injuries caused by needles, scalpels, and other sharp instruments or devices during procedures; when cleaning used instruments; during disposal of used needles; and when handling sharp instruments after procedures. To prevent needlestick injuries, needles should not be recapped by hand, purposely bent or broken by hand, removed from disposable syringes, or otherwise manipulated by hand. After they are used, disposable syringes and needles, scalpel blades, and other sharp items should be placed in puncture-resistant containers for disposal. The puncture-resistant containers should be located as close as practical to the use area. All reusable needles should be placed in a puncture-resistant container for transport to the reprocessing area.

General infection control practices should further minimize the already minute risk for salivary transmission of HIV. These infection control practices include the use of gloves for digital examination of mucous membranes and endotracheal suctioning, handwashing after exposure to saliva, and minimizing the need for emergency mouth-to-mouth resuscitation by making mouthpieces, and other ventilation devices available for use in areas where the need for resuscitation is predictable.

Although universal precautions do not apply to human breast milk, gloves may be worn by health-care workers in situations where exposures to breast milk might be frequent, for example, in breast milk banking.

For information about the Occupational Safety and Health Administration (OSHA) proposed rule on occupational exposure to bloodborne pathogens, call 202-523-7157.


Written Guidelines - Universal Precautions

Universal Precautions including the use of protective barriers in health-care settings and by public safety workers are discussed in the following documents:

First: "Recommendations for Prevention of HIV Transmission in Health-Care

Settings", published on August 21, 1987 as a supplement to the MMWR, the Morbidity and Mortality Weekly Report.
Second: "Update: Universal Precautions for Prevention of Transmission of

Human Immunodeficiency Virus, Hepatitis B virus, and Other Bloodborne Pathogens in Health-Care Settings", published on June 24, 1988, in the MMWR, and
Third: "Guidelines for Prevention of Transmission of Human

Immunodeficiency Virus and Hepatitis B Virus to Health-care and Public-Safety Workers," published on June 23, 1989, in the MMWR.

These 3 documents may be obtained by calling the AIDS Hotline 1-800-342-2437 or the National AIDS Information Clearinghouse at 1-800-458-5231.

In addition, OSHA or Occupational Safety or Health Administration has a proposed rule on occupational exposure to bloodborne pathogens. For information about this document, call 202-523-7157.

For information on infection control in dental practice, call the Division of Oral Health, National Center for Prevention Services, CDC, telephone number 404-639-8376.


Sterilization, Disinfection, Decontamination of Patient-Care Equipment

The following are part of the CDC recommendations for the prevention of transmission of HIV and other bloodborne infections.

The following general principles apply to most questions CDC receives about sterilization or disinfection of patient-care equipment in relation to HIV. However, this information is not comprehensive. Therefore, it is advisable for you to obtain a copy of the guidelines from which these statements have been derived.

  1. Commonly used chemical germicides at concentrations much lower than commonly used in practice can rapidly inactivate HIV.
  2. Chemical germicides that are registered as "sterilants" with the U.S. Environmental Protection Agency or EPA may be used either for sterilization or high-level disinfection of medical devices, depending on contact time. In addition to EPA-registered commercial chemical germicides, an inexpensive germicide effective against HIV is a solution of sodium hypochlorite (1 part household bleach to 99 parts water or 1/4 cup bleach to 1 gallon of water) prepared daily. Bleach, however, is corrosive to metals, and should not be used to decontaminate medical instruments with metallic parts.
  3. In general, reusable instruments or devices that enter sterile tissue including the vascular system of any patient, and devices through which blood flows should be sterilized before reuse.
  4. Reusable devices or items that contact intact mucous membranes should be sterilized or receive high-level disinfection before reuse. For example, depending on compatibility, contact lenses used in trial fittings should be disinfected after each fitting by using a commercially available hydrogen peroxide contact lens disinfecting system or, by heating at (78-80 degrees C) for 10 min.
  5. Medical devices that require sterilization or disinfection should be thoroughly cleaned to reduce material/bioburden before being exposed to the germicide, and the germicide and device manufacturers' instructions should be closely followed.
  6. Extraordinary attempts to disinfect surfaces such as walls or floors are not necessary. However, cleaning and removal of soil should be done routinely.
Chemical germicides that are EPA-approved for use as "hospital disinfectants" and are tuberculocidal/virucidal when used at recommended dilutions and contact times can be used to decontaminate spills of blood or other body fluids that contain blood in the following areas:

  1. In patient-care areas, visibly soiled areas should first be cleaned and then chemically decontaminated. For disinfection, the pre-cleaned areas should be moistened with the appropriate germicide and allowed to air-dry.
  2. With large spills of cultured or concentrated infectious agents in the laboratory, the contaminated area should be flooded with a liquid germicide before cleaning, then decontaminated with fresh germicidal chemical after organic material has been removed. It is not necessary to flood spills of human-source material with germicide before cleaning.
Gloves should always be worn during cleaning and decontaminating procedures.

If you have questions about a particular germicidal product, contact your local or state health department, or the Antimicrobial Program Branch, Registration Division, Environmental Protection Agency (EPA), telephone no. 703-557-7443. The EPA is the federal regulatory agency for germicidal chemicals.

If you have questions about cleaning, disinfecting or sterilizing a particular medical device, first contact the manufacturer of the device. If sufficient information cannot be obtained in this manner, contact the Food and Drug Administration (FDA) regional office or the FDA Center for Devices and Radiological Health, Division of Compliance Program, telephone number 301-443-4690. FDA is the federal regulatory agency for safe and effective use of medical devices.


Laundry

Hygienic and common-sense collection, storage and processing of soiled linen are recommended. Soiled linen should be handled as little as possible and with minimal agitation. All soiled linen should be bagged at the location where it was used. Linen soiled with blood or body fluids should be placed and transported in bags that prevent leakage. All normal washing and drying cycles are adequate to ensure patient safety. Instructions of the manufacturers of the machine and the detergent or wash additive should be followed closely.

For more information on laundry, refer to the CDC Guideline for Handwashing and Environmental Control. This document is available as publication number PB85-923404 from the National Technical Information Service, Telephone number (703) 487-4650.


Disinfection, Sterilization, Decontamination Publications

The CDC Guideline for Handwashing and Hospital Environmental Control published in 1985, contains recommendations for handling and processing of potentially contaminated patient-care items including those that are contaminated with blood or other body fluids from persons infected with HIV.

Copies of this guideline may be purchased as publication number PB85-923404, from the National Technical Information Service, tel. no. (703) 487-4650.

In addition, 2 supplements of the Morbidity and Mortality Weekly Report, namely, "Recommendations for Prevention of HIV Transmission in Health-Care Settings," published on August 21, 1987, and the "Guideline for Prevention of Transmission of HIV and Hepatitis B Virus to Health-Care and Public-Safety Workers," published on June 23, 1989, provide recommendations for appropriate decontamination of environmental surfaces, and disinfection or sterilization of patient-care equipment. Health-care workers responsible for sterilization or disinfection are encouraged to familiarize themselves with the recommendations contained in these guidelines. Copies of these 2 documents may be obtained by calling the National AIDS Hotline 1-800-342-2437 or the AIDS Information Clearinghouse at 1-800-458-5231.


Surveillance Summary

Data from several ongoing surveillance studies indicate that the risk of acquiring HIV after a needlestick-exposure to HIV-infected blood is about 0.3%.

In August, 1983, the CDC initiated a nationwide surveillance project to assess the risk to health-care workers of acquiring HIV infection resulting from a documented parenteral or mucous-membrane exposure to the blood or other body fluids of an HIV-infected person. As of June 30, 1990, a total of 1372 health-care workers exposed to blood of HIV-infected persons had been enrolled in the project and tested for HIV antibody at least 180 days after exposure. One thousand, two hundred and seven (88%) had parenteral exposures, 90 (7%) had open-wound exposures, and 75 (5%) had mucous-membrane exposures. Of the 1207 workers with parenteral exposures, 4 (0.3%) were seropositive for HIV antibody. One of these four was not tested until 10 months after a needlestick; this worker had a sexual partner who was also HIV-antibody positive. Thus, in this case, heterosexual transmission could not be ruled out. The remaining 3 health-care workers each sustained needlestick injury, tested negative for HIV antibody initially, suffered an acute mononucleosis-like illness within 1 month after the exposure, and subsequently became HIV-antibody positive within 6 months after the date of exposure.

Of the 165 health-care workers who had open-wound or mucous-membrane exposures, none seroconverted.

In other prospective studies in the U.S., 3 other health-care workers have been documented to seroconvert to HIV after percutaneous exposure to HIV- infected blood. For more information on these cases, please refer to the Morbidity and Mortality Weekly Report of April 22, 1988, Vol. 37, No. 15.

If your hospital wishes to enroll an individual in CDC's ongoing national surveillance of health-care workers who have been occupationally exposed to HIV, please contact your infection control practitioner, State Health Department, or the Centers for Disease Control at (404)-639-1644 .


Management of Exposures

An occupational exposure that may place a worker at risk of HIV infection is defined as a percutaneous injury (e.g., a needlestick or cut with a sharp object), contact of mucous membranes, or contact of skin with blood, tissues, or other body fluids to which universal precautions apply, including laboratory specimens that contain HIV (especially when the exposed skin is chapped, abraded, or afflicted with dermatitis or the contact is prolonged or involving an extensive area). After an occupational exposure, the source patient should be informed of the incident and tested for serologic evidence of HIV infection and Hepatitis B surface antigen after consent is obtained. Policies should be developed for testing source patients in situations in which consent cannot be obtained (such as in the case of an unconscious patient). If the source patient has AIDS, is known to be HIV-seropositive, or refuses testing, the worker should be evaluated clinically and serologically for evidence of HIV infection as soon as possible after the exposure(baseline) and if seronegative, should be retested periodically for a minimum of 6 months after exposure (for example, 6 weeks, 12 weeks, and 6 months after exposure) to determine whether HIV infection has occurred. The worker should be advised to report and seek medical evaluation for any acute illness that occurs during the follow-up period. Such illness, particularly if characterized by fever, rash, or lymphadenopathy, may be indicative of acute HIV infection, drug reaction, or another medical condition. During the follow-up period, especially the first 6-12 weeks after the exposure when most infected persons are expected to seroconvert, exposed workers should follow PHS recommendations for preventing transmission of HIV. These recommendations include refraining from blood, semen, or organ donation and abstaining from or using measures to prevent HIV transmission during sexual intercourse. In addition, in countries such as the United States where safe and effective alternatives to breast-feeding are available, exposed women should not breastfeed infants during the follow-up period in order to prevent the infant's possible exposure to HIV in breast milk. During all phases of follow-up, confidentiality of the worker and the source patient should be protected.

If the source individual is HIV-seronegative and has no clinical manifestations of AIDS or HIV infection, no further HIV follow-up of the exposed worker is necessary unless epidemiologic evidence suggests that the source individual may have recently been exposed to HIV or if testing is desired by the worker or recommended by the health-care provider. In these instances, the guidelines may be followed as described earlier.

If the source individual cannot be identified, decisions regarding appropriate follow-up should be individualized, based on factors such as whether potential sources are likely to include a person at increased risk of HIV infection.

The employer should make serologic testing available to all workers who are concerned about possible infection with HIV through an occupational exposure. Appropriate psychological counseling may be indicated as well.

If your hospital wishes to enroll an individual in CDC's ongoing national surveillance of health-care workers who have been occupationally exposed to HIV, please contact your infection control practitioner, State Health Department, or the Centers for Disease Control at (404)-639-1644 .

For information on the management of exposure to Hepatitis B, refer to the document entitled "Protection against Viral Hepatitis" published in the February 9, 1990 issue of the Morbidity and Mortality Weekly Report, volume 39, no. RR-2. Copies may be purchased from the Government Printing Office, telephone number 202-783-3238.


Infection Control in Dental Practice

Infection control precautions for dentistry are discussed in detail in the article entitled "Recommended infection-control practices for dentistry," published in the April 18, 1986 issue of the Morbidity and Mortality Weekly Report, volume 35, pages 237-242. Copies of this document are available from the National AIDS Information Clearinghouse, telephone number 1-800-458-5231. If you are a dental worker, and desire to have more information about infection control in dentistry, you may contact the Division of Oral Health, Center for Prevention Services, CDC, at 404-639-8376. If you are a lay person and wish to obtain more information about HIV and dentistry, please call the AIDS hotline 1-800-342-2437.


Guidelines for Prevention of Transmission of HIV to Health-Care and Public Safety Workers

The "Guidelines for Prevention of Transmission of Human Immunodeficiency Virus and Hepatitis B Virus to Health-Care and Public-Safety Workers," contains: an overview of the modes of transmission of HIV and Hepatitis B virus in the workplace, and specific risk-control recommendations for employers and workers, including recommendations for management of exposures to Hepatitis B and HIV. To obtain a copy of this guideline, please call the National AIDS Information Clearinghouse at 1-800-458-5231.


AZT Post-Exposure use, General Information

Zidovudine, also known as azidothymidine, AZT, or Retrovir has been approved for marketing by the Food and Drug Administration and has been indicated for the treatment of patients with established HIV infection.

Some physicians and some institutions have offered health-care workers the option of zidovudine use after occupational exposure to HIV. Existing data from animal and human studies, however, are inadequate to establish the efficacy or safety of such use.

Detailed information regarding post-exposure zidovudine use is discussed in a report entitled "Public Health Service Statement on Management of Occupational Exposure to Human Immunodeficiency Virus, Including Considerations Regarding Zidovudine Postexposure Use," published on January 26, 1990, in the Morbidity and Mortality Weekly Report, Volume 39, No. RR-1. Single copies are available from the National AIDS Information Clearinghouse, Telephone No. 800-458-5231.

At this time, prophylaxis with zidovudine cannot be considered a necessary component of postexposure management. However, workers who might be at risk of occupational exposure to HIV should be informed, as part of job orientation and ongoing job training, of the considerations pertaining to the use of zidovudine for postexposure prophylaxis. For example, the worker should be informed regarding the: a) theoretical rationale for postexposure prophylaxis, b) risk of occupationally acquired HIV infection due to the exposure, c) limitations of current knowledge of the efficacy of zidovudine when used as postexposure prophylaxis, d) current knowledge of the toxicity of zidovudine and the limitations of this knowledge in predicting toxicity in uninfected individuals who take the drug after occupational exposures, and e) the need for postexposure follow-up. The worker should be informed that there are diverse opinions among physicians regarding the use of AZT for postexposure prophylaxis, and that the PHS cannot make a recommendation for or against the use of AZT for this purpose because of limitations of current knowledge.

If a physician is deciding whether or not to offer, and a worker is deciding whether or not to take, zidovudine after occupational exposure to HIV, the following should be taken into consideration: the likelihood that the source fluid contained HIV and the concentration of HIV in the source fluid, the route of exposure, and volume of fluid involved. Such decisions have to be made promptly because it is recommended that if Zidovudine is to be given at all, it should be given as soon as possible after exposure. In addition, the physician or other appropriate health-care provider should obtain a written consent from the worker for the use of the drug.


AZT Dose Schedules after Occupational Exposure to HIV

Various regimens have been prescribed for zidovudine use after occupational exposure to HIV. No data are available to enable investigators to determine the efficacy or compare the toxicity of these or other regimens. At the National Institutes of Health Clinical Center, workers who elect to receive zidovudine are treated with 200 milligrams every 4 hours (six times daily) for 6 weeks. At San Francisco General Hospital, workers who elect to receive zidovudine are treated for 4 weeks with 200 milligrams every 4 hours (5 times daily, with no dose given at 4:00 a.m.). Some clinicians have used an initial dose of 400 milligrams, and others have prescribed treatment courses ranging from 4 days to 4 months. Doses may be reduced in workers who experience drug toxicity. At several institutions, attempts are made to begin zidovudine administration within one hour after exposure to workers who elect to receive the drug.


AZT Toxicity

Preliminary data from a study sponsored by Burroughs-Wellcome Company, of health-care workers who received 200 milligrams of zidovudine or placebo every 4 hours for 6 weeks after occupational exposure to HIV indicate that adverse effects most frequently consisted of nausea and vomiting. In no instance did the prescribing physician discontinue a participant's study drug or placebo because of hematologic or other serious toxicity; however, during the therapy period, 14 (28.6%) of 49 participants who received zidovudine had a hemoglobin concentration between 9.5 and 12 grams per deciliter, compared with one (2.9%) of 35 participants in the placebo group. Seven (14.3%) of the 49 participants who received zidovudine, compared with one (2.9%) of the 35 placebo recipients, elected to discontinue therapy because of subjective, reversible symptoms, including nausea, vomiting, fatigue, headache, myalgia, or cough.

Among 55 health-care workers enrolled in the CDC surveillance project, and who took post-exposure AZT, 71% had one or more symptoms, most commonly nausea, malaise or fatigue, and headache. Four percent had a decrease in hemoglobin while using AZT. The prescribed AZT course could not be completed by 31% of those who started post-exposure AZT.

Although the risk of acute zidovudine toxicity for exposed health-care workers cannot be determined from this limited information, available data suggest that the risk of acute toxicity associated with short-term use of the drug is lower than the risk observed during long-term therapy of symptomatic HIV-infected individuals.

For healthy persons not infected with HIV, the risk of long-term toxicity is not known. This includes teratogenic and carcinogenic effects, related to a course of zidovudine.


AZT Studies

CDC has a registry for occupational exposures to HIV, and whether post-exposure AZT is used. To enroll in this registry, call 404-639-1644.

To enroll in the Burroughs-Wellcome study of women who receive AZT during pregnancy, call collect 919-248-8465 or 1-800-722-9272.


Prevention of Tuberculosis Transmission Involving HIV-Infected Patients.

Precautions to prevent airborne transmission of tuberculosis are particularly important during and immediately following procedures which stimulate coughing, e.g., sputum collection, sputum induction, bronchoscopy and aerosolized pentamidine treatments in persons who may be at risk for tuberculosis. Unless pulmonary tuberculosis has been ruled out or is extremely unlikely, such procedures should be carried out in individual rooms or booths, with negative air pressure in relation to adjacent rooms or hallways, with air exhausted directly to the outside and away from intake sources. The number of air exchanges in the room or booth should be sufficient to remove infectious organisms during the average time between patients.

Patients with pulmonary or laryngeal TB are most infectious before diagnosis and treatment. Therefore, health-care providers should note the recommendation to exclude active pulmonary disease in a patient before starting the aerosolized pentamidine treatment.

If you have questions on current recommendations for TB control, call (404)639-2501.


Aerosols and HIV

Aerosols should not be confused with droplets and splashes. CDC recommends barrier precautions (face shields, masks, gowns, etc.) to prevent contact with droplets and splashes. Aerosols are not droplets; they are invisible particles less than 10 microns in diameter which float on air currents. Aerosols require considerable energy to generate and are not likely to be present in most clinical settings. There are no known instances of transmission of a bloodborne pathogen by aerosol in a clinical setting. In studies conducted in dental operatories and hemodialysis centers, hepatitis B surface antigen could not be detected in the air during the treatment of hepatitis B carriers, including during procedures known to generate aerosols. This suggests that detection of HIV in aerosols would also be uncommon, since the concentration of HIV in blood is generally lower than that of HBV. Finally, detection of HIV in an aerosol would not necessarily mean that HIV is readily transmissible by this route.

In the health-care setting, the major risks are blood contact due to percutaneous injuries, and to a lesser extent, mucous membrane and skin contact. Although CDC is sponsoring additional research on aerosol issues, the possibility that HIV may be transmitted via aerosolized blood must be considered theoretical at this time. For additional information on this topic, refer to an article entitled "An Assessment of the Airborne Route in Hepatitis B Transmission," by NJ Petersen, published in 1980 in the Annals of the New York Academy of Sciences, Volume 353, pages 157-166.


Sterilization, Disinfection, and Laundry

The following general principles are applicable to most questions CDC receives about sterilization or disinfection of patient-care equipment in general. However, these statements are not comprehensive. Therefore, it is advisable for you to obtain a copy of the CDC Guideline for Handwashing and Hospital Environmental Control, Publication Number PB85-923404, from the National Technical Information Service, Telephone Number 703-487-4650.

  1. Chemical germicides that are registered as "sterilants" with the U.S. Environmental Protection Agency or EPA may be used either for sterilization or high-level disinfection of medical devices, depending on contact time.
  2. In general, reusable medical devices or patient-care equipment that enter normally sterile tissue or the vascular system or through which blood flows should be subjected to a sterilization procedure before each use.
  3. Laparoscopes, arthroscopes, and other scopes that enter normally sterile tissue should be subjected to a sterilization procedure before each use; if this is not feasible, they should receive at least high-level disinfection.
  4. Reusable devices or items that touch mucous membranes should at the minimum, receive high-level disinfection. These devices include endoscopes, endotracheal tubes, anesthesia breathing circuits, respiratory therapy equipment, contact lenses used for trial fittings, vaginal speculums and thermometers.
  5. Medical devices that require sterilization or disinfection should be thoroughly cleaned to reduce organic material or bioburden before being exposed to the germicide, and the germicide and the device manufacturer's instructions should be closely followed.
  6. Items that do not ordinarily touch the patient or touch only intact skin rarely, if ever, transmit disease. These items include crutches, bedboards, blood pressure cuffs, and a variety of other medical accessories. Consequently, depending on the particular piece of equipment or item, washing with a detergent may be sufficient. If they are grossly soiled with blood or body fluids that require universal precautions, follow instructions outlined in the section on HIV, sterilization and disinfection.
If you have questions about a particular germicidal product, contact your local or state health department, or the Antimicrobial Program Branch, Registration Division, Environmental Protection Agency (EPA), Telephone Number (703) 557-7443. The EPA is the federal regulatory agency for germicidal chemicals.

If you have questions about cleaning, disinfecting or sterilizing a particular medical device, first contact the manufacturer of the device. If sufficient information cannot be obtained in this manner, contact the Food and Drug Administration (FDA) regional office or the FDA Center for Devices and Radiological Health, Telephone Number (301) 443-4690. FDA is the federal regulatory agency for safe and effective use of medical devices.


Laundry

Hygienic and common-sense collection, storage and processing of soiled linen are recommended. Soiled linen should be handled as little as possible and with minimal agitation. All soiled linen should be bagged at the location where it was used. Linen soiled with blood or body fluids should be placed and transported in bags that prevent leakage.

All normal washing and drying cycles are adequate to ensure patient safety.

Instructions of the manufacturers of the machine and the detergent or wash additive should be followed closely.

For more information on laundry, refer to the CDC Guideline for Handwashing and Environmental Control which is available as publication number PB85-923404 from the National Technical Information Service, Telephone number (703) 497-4650.


Medical Waste

There is no epidemiologic evidence to suggest that most hospital waste is any more infective than residential waste. Moreover, there is no epidemiologic evidence that current hospital waste disposal practices have caused disease in the community. Therefore, identifying wastes for which special precautions are necessary is largely a matter of judgment about the relative risk of disease transmission. Hospital wastes for which special precautions appear prudent are microbiology laboratory waste, pathology waste, bulk blood or blood products and sharp items such as used needles or scalpel blades. In general, these items should either be incinerated or decontaminated prior to disposal in a sanitary landfill. Bulk blood, suctioned fluids, excretions, and secretions may be carefully poured down a drain connected to a sanitary sewer. Sanitary sewers may also be used to dispose of other infectious wastes capable of being ground and flushed into the sewer.

Please refer to your particular state or local health department for information about laws on waste disposal in your own area.


Methicillin-Resistant Staphylococcus Aureus

Methicillin-resistant Staphylococcus aureus or MRSA has become a significant nosocomial pathogen in the USA. In hospitals, the most important reservoirs of MRSA are colonized or infected patients. Although hospital personnel can serve as a reservoir for MRSA and harbor the organism for many months, they have been more commonly identified as a link for transmission between colonized or infected patients. The main mode of transmission of MRSA is via health-care workers' hands, which may become contaminated by contact with infected or colonized patients or by contact with colonized or infected sites of the personnel themselves. The role of the environment as a reservoir needs to be assessed, but it is known that heavy environmental contamination can occur in burn units.

To control the spread of MRSA, contact isolation is recommended for patients infected or colonized with the microorganism. Contact isolation consists of the following:

  1. using gloves for touching infective material and changing them between patient contacts;
  2. washing hands after touching the patient or potentially contaminated articles and before taking care of another patient, whether or not gloves are worn;
  3. using masks for those who come in close contact with the patient;
  4. using gowns if soiling is likely; and
  5. using a private room. Patients infected with the same organism may share a room. A private room encourages handwashing between patient contacts by health-care personnel and other persons who may come in contact with the patient.
Articles contaminated with infective material should be discarded or bagged and labeled before being sent for decontamination and reprocessing.


Control of MRSA Outbreak

When an outbreak of MRSA occurs, an epidemiologic assessment should be initiated to identify risk factors for MRSA acquisition in the institution. Colonized or infected patients should be identified as quickly as possible, appropriate barrier precautions should be instituted, and handwashing by medical personnel before and after all patient contacts should be strictly implemented. Unless the objective of the hospital is to eventually treat all MRSA carriers whether or not they disseminate MRSA, it is prudent to culture only personnel who are implicated in MRSA transmission based on epidemiologic data. MRSA-carrier personnel who are epidemiologically linked to transmission should be removed from direct patient-care until treatment of the MRSA-carrier status is successful. If the hospital elects to culture all personnel to identify MRSA carriers, it is likely that personnel colonized by MRSA who are not epidemiologically linked to transmission and/or who may not be MRSA disseminators will be identified, subjected to treatment or removed from patient contact unnecessarily. Because of these serious consequences to health-care workers, hospitals should weigh the advantages and the consequences of routinely culturing personnel before doing so.

During an outbreak, all personnel should be re-instructed on appropriate precautions for patients colonized or infected with multiple resistant microorganisms and on the importance of handwashing and barrier precautions in preventing contact transmission.


National Noscomial Infection Surveillance Rates and Definitions

You can receive information on CDC definitions of nosocomial infections, including surveillance data for infection rates, and how to participate in surveillance, in one of two ways. First, you can listen to the information in this service, or secondly, you can have the information faxed to you, provided you have a fax machine available, and you know your fax number.


National Rates of Noscomail Infections

Data on infections acquired in acute-care institutions in the United States are reported to the CDC by volunteer hospitals that participate in the National Nosocomial Infection Surveillance System, or NNIS. NNIS does not collect information on infections in nonacute-care settings such as extended-care, psychiatric, or rehabilitation facilities. The last comprehensive report from NNIS, entitled "Nosocomial Infection Surveillance, 1984", was published in the 1986 Morbidity and Mortality Weekly Report Surveillance Summary, volume 35, no. 1SS, pages 17SS-29SS. A copy of this report may be obtained by writing to: Surveillance Activity, Hospital Infections Program, Mailstop A07, Centers for Disease Control and Prevention, Atlanta Georgia, 30333. The report contains information on: distributions and rates of nosocomial infections stratified by size and type of institution; pathogens by service and body site; antimicrobial resistance trends; and occurrence of adverse outcomes such as secondary bacteremia and death. Because these data were not adjusted for confounders such as severity of patient's underlying illness, they cannot be used as "national norms" or standards for interhospital comparison.

Since 1986, however, NNIS has collected data which may be used for interhospital comparisons. Most of this current information will be published in a supplement to the American Journal of Medicine as part of the proceedings of the Third International Conference on Nosocomial Infections.


Joining NNIS

If you are interested in joining the National Nosocomial Infections Surveillance System or NNIS, you may write for an application and information packet to: NNIS, c/o Surveillance Activity, Hospital Infections Program, Mailstop A07, Centers for Disease Control, Atlanta, GA 30333.


CDC Definitions

The "CDC Definitions for Nosocomial Infections, 1988" are criteria used by hospitals that participate in the CDC's National Nosocomial Infections Surveillance System (NNIS) to identify nosocomial infections at different body sites. New definitions were published in the June 1988 issue of the American Journal of Infection Control. A copy of the document may be purchased from the National Technical Information Service, telephone number 703-487-4650, (Order No. PB88-187117).


Long-Term Care Facilities

The Hospital Infections Program of the Centers for Disease Control and Prevention has not developed guidelines specifically addressing the prevention and control of infections in long-term care facilities. However, some long-term care facilities in the US have adapted and/or modified the CDC Guidelines for Prevention and Control of Nosocomial Infections to meet their particular needs. In addition, some state health departments have designed their own policies regarding infection control in long-term care facilities, for example, control of MRSA in nursing homes.

There are also several non-CDC publications on infection control in long-term care facilities:

  1. Infection Control in Long-Term Care Facilities by PW Smith, and Published by Delmar Publishers Incorporated, 1984.
  2. Infections in the Elderly by RA Gleckman and NM Glanz, published by Little, Brown and Company, 1983.
  3. Infection Control Manual and Resource Book for Nursing Homes by Nancy Satterfield, published by Eldercare Consultants Inc., 1988.
(For ordering information on this last book, call Eldercare Consultants, Inc., 320 Pinyan Place, Woodstock, GA 30188, telephone number 404-998-8441.)

Another source of information would be infection control practitioners from other institutions similar to yours in your area. A chapter of the Association for Practitioners in Infection Control (APIC) in your area may be able to provide you with names of practitioners and other resources. For information about APIC local chapters, call the APIC headquarters in Mundelein, Illinois at 708-949-6052.


Infection Control Courses

Training courses for Infection Control Practitioners and Hospital Epidemiologists are offered by the Association for Practitioners in Infection Control or APIC and the Society for Hospital Epidemiologists of America or SHEA, respectively. For more information on these and other courses in Hospital Epidemiology, call APIC at 708-949-6052 or SHEA at 617-735-7623.

POINT OF CONTACT FOR THIS DOCUMENT:

To request a copy of this document or for questions concerning this document, please contact the person or office listed below. If requesting a document, please specify the complete name of the document as well as the address to which you would like it mailed. Note that if a name is listed with the address below, you may wish to contact this person via CDC WONDER/PC e-mail.
HOSPITAL INFECTIONS PROGRAM
CDC/NCID/HIP J. Shaw
1600 Cliftion Rd. NE MS(A-07)
Atlanta, GA 30333



This page last reviewed: Friday, July 13, 2007
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