The prevalence of tuberculosis (TB) infection in healthcare workers (HCWs) is completely unknown in Mexico. To evaluate the frequency of TB infection in our hospital, we performed a prevalence study of tuberculin reactivity among a random sample of asymptomatic HCWs. Our results showed an extremely high prevalence of PPD reactivity (70%) among 175 HCWs, probably related to the high incidence of active TB in the general population and to the absence of preventive programs.

The widespread dissemination of a single clone of methicillin-resistant Staphylococcus aureus (MRSA) in several hospitals in Sao Paulo could make the intrahospital epidemiologic evaluation of MRSA outbreaks very difficult. The high index of PPD reactivity among our healthcare workers (HCWs) obligates us to develop programs suitable to the prevailing conditions of Latin American hospitals to control TB inside healthcare facilities.

The danger of exposure to tuberculosis (TB) exists primarily in facilities in which people with TB are likely to mingle with uninfected susceptible people. Such places include, among others, healthcare facilities in areas where TB is prevalent, shelters for the homeless in large cities, drug treatment centers, and prisons. If a given facility is identified as hazardous, an effective method for interrupting airborne transmission of TB is air disinfection with ultraviolet germicidal irradiation (UVGI). In this article, implementation of this method will be discussed: where, within a given building, UVGI fixtures should be installed; and what fixture design should be chosen for each location.

Where to install ultraviolet (UV) fixtures depends on where the hazard of airborne TB exists, and that depends on the behavior of infected people and the behavior of infectious airborne particles. Patients with known active TB normally are sequestered in isolation rooms where special precautions are taken to avoid transmission of infection. However, as stated succinctly in 1967 in a document accepted by the National Tuberculosis Association Board of Directors: “It should be made clear that the greatest risk of infection arises from the individual with undiagnosed or unsuspected tuberculosis.” Such people usually are unaware that they are infectious. They may be seated in clinic waiting rooms, walking the hospital corridors, or visiting in patients' rooms. If the unsuspected case is a member of the housekeeping or healthcare staff, he or she may be found anywhere in the building. The behavior of infectious airborne particles is equally unpredictable.

Varicella exposures in the hospital setting cause problems of management of nonimmune employees. There has been a great deal written about the number of varicella exposures and the problems created by them but few practical recommendations for prevention or management of such exposures, including management of exposed nonimmuneemployees.

In 1983, the Centers for Disease Control and Prevention (CDC) published Guidelines for Infection Control in Hospital Personnel. The CDC is quite clear on their recommendations for personnel exposed to varicella or zoster and state (as a Category I recommendation): “After exposure to varicella or zoster, personnel not known to be immune to varicella (by history or serology) should be excluded from work beginning on the tenth day after exposure and remain away from work for the maximum incubation period of varicella (21 days). Personnel who have onset of varicella should be excluded from work at least until all lesions have dried and crusted.” The CDC suggests it may be useful to screen those personnel who have a negative or equivocal history of varicella for the presence of serum antibodies to varicella zoster virus (VZV) to document susceptibility or immunity.

There have been many changes in infection control in the 10 years since the last publication of isolation guidelines for hospitals by the Centers for Disease Control and Prevention (CDC). Hospitals since have used the 1988 CDC Update on Universal Precautions as a minimum because it is required by the Occupational Safety and Health Administration. Even before these changes, Lynch and Jackson described the concept of body substance isolation, which is intended primarily to decrease cross-transmission between patients. Many hospitals' universal precautions policies also incorporate the concept of body substance isolation to prevent the transmission of non-bloodborne as well as bloodborne pathogens. The 1988 CDC update states that the use of universal precautions does not eliminate the need for other category- or disease-specific isolation, or an institution's own system of isolation precautions.

West Haven Veterans Affairs Medical Center in Connecticut and the University Health System and Audie L. Murphy Memorial Veterans Hospital in San Antonio, Texas, have adopted a universal precautions/body substance isolation (UP/BSI) policy as a standard for all patients in an attempt to lessen the confusion. All three hospitals are large, university-affiliated, tertiary care teaching institutions. Blood and all body fluids or tissue from all patients are considered potentially infectious and barrier precautions are used accordingly. Body substance isolation has been shown to decrease the transmission of some non-blood-borne pathogens.

Few issues in hospital infection control have evoked as much debate as the controversies regarding the risk and prevention of transmission of blood-borne pathogens to healthcare workers and patients during invasive procedures. To promote direct discussions among researchers and other interested participants from multiple disciplines affected by these issues, the American College of Surgeons and the Centers for Disease Control and Prevention cosponsored a Conference on Prevention of Transmission of Bloodborne Pathogens in Surgery and Obstetrics, February 13-15, 1994, in Atlanta, Georgia. The conference was attended by approximately 200 participants from nine countries, including surgeons from a variety of specialties, obstetricians, operating and delivery room personnel, anesthesiologists, hospital epidemiologists and infection control personnel, occupational health specialists, and public health professionals.

Titles of plenary sessions included Risk of Occupational Transmission of Bloodborne Pathogens, Microbiologic Aspects (dealing with aerosols and disinfection and sterilization issues), Prevention of Injuries by Needles and Other Sharp Instruments, Hand Protection, Body and Facial Protection, Evaluation of New products on the Market, Postexposure Management, Are Universal Precautions Realistic, and Bloodborne Pathogen Transmission to Patients. Feedback from the attendees indicated that the conference achieved its goals and that future conferences on these issues would be welcome.