Imipenem, a new carbapenem ß-lactam broad-spectrum antibiotic, is highly active in vitro against most aerobic and anaerobic gram-positive and gram-negative bacteria isolated from infectious diseases of human beings. Except for enterococci and methicillin-resistant staphylococci most gram-positive cocci are inhibited by <2 μg/ml. Although the MIC-90 of methicillin-resistant staphylococci may be <4 μg/ml, these bacteria are usually resistant to imipenem by modified testing methods. The enterococcus, S. faecalis, has an MIC-90 of <8 μg/ml but bactericidal concentration may be much higher. Most Enterobacteriaceae are highly susceptible to imipenem with MIC-90 of 0.5 to 2.0 μg/ml. Proteus species are less susceptible with MICs of 4 to 8 μg/ml. Isolates of P. aeruginosa have variable susceptibility with MICs ranging from 0.25 to 16 μg/ml. Pseudomonas maltophilia and P. cepacia are usually resistant to imipenem. Except for Clostridium species, most strict anaerobes are susceptible to <1.0 μg/ml of imipenem. When combined with cilastatin (1:1 ratio), the renal elimination of the active form is increased. The serum half-life in normal renal function is about 1 hour and increases to 3.4 hours in anuria. Major adverse effects are similar to those of cephalosporins except for seizures in some patients. Colonization with fungi and drug-resistant bacteria occurs in about 5% of imipenem-treated patients. Clinical studies have demonstrated efficacy in 79% to 96% of patients treated.

The recognition of serratia as an opportunistic human pathogen can be dated from 1959, when the microorganism entered the family of Enterobacteriaceae, with features recognizable in the clinical laboratory and related to the Klebsiella/Enterobacter group. Since then, physicians have been challenged to establish the significance of isolation of serratia from a clinical specimen.

The international recognition of the emergence of methicillin-resistant Staphylococcus aureus as major nosocomial pathogens dates to the late 1970s. The weight of evidence from many institutions suggests that transmission involves spread from patient to patient of the same or very similar strain and that effective control, if not elimination, involves isolation of infected and colonized patients.

More recently, a number of reports have suggested the emergence of methicillin-resistant S. epidermidis and other coagulase-negative staphylococci as significant nosocomial pathogens. Although the organisms undoubtedly share many similarities with methicillin-resistant strains of S. aureus, it is certain that biologic differences exist which are important for infection control.

Why are blood cultures drawn? Is there a purpose to the blood culture or is it a reflex reaction to a fever? Nurse says, “patient has fever,” Doctor replies “draw blood culture.” I fear that the latter is all too often the scenario that exists in the hospital today. As we enter an era where the extra laboratory tests do not “make money, keep the techs employed and justify the lab,” we must re-examine the rationale for blood cultures.

Effects of ultra high speed (UHS) floor burnishing upon air quality in health care facilities were evaluated. A 2,000-rpm burnisher can disseminate high-velocity (190 km/hr) dust and microbial particles. A UHS burnisher used with either inadequate or no air restraint produced significant increases (P<0.05) in the levels of airborne dust particles and microorganisms. A UHS burnisher equipped with an air restraint assembly specifically designed for use in health care facilities produced no significant increase (P>0.05) in the levels of airborne dust particles or microorganisms when compared to ambient air levels. The types and distribution of airborne microorganisms isolated from microbial air samples were not unusual nor were they directly influenced by the floor burnishing processes. Furthermore, the UHS floor burnishing process produced a significant reduction (P<0.05 ) in microbial floor contaminants (96%). When the use of UHS floor burnishing is contemplated for productivity improvement and esthetic enhancement, the possible adverse effects on air quality should also be considered.

Given the wide range of available health care personnel handwashing agents, selection of an appropriate product may be difficult. This decision may be made on the basis of user preference, cost, or other factors unrelated to product effectiveness. Four criteria—efficacy, safety, cost, and acceptability—are appropriate for systematic evaluation of handwashing products. These criteria are applied to para-chloro-meta-xylenol (PCMX), a compound used with increasing frequency in health care personnel handwashing agents. Published data regarding the biochemical properties, efficacy, and safety of PCMX are summarized. We conclude that the substance appears to be safe and efficacious. However, the activity of PCMX is highly formula-dependent and many of the studies available in scientific literature have been conducted in Europe using a variety of testing conditions and formulations different from those currently available in the US. Clinical studies of marketed formulations are beginning to appear in the literature. Such studies will provide the data needed for adequate product evaluation.

Following an outbreak of varicella, 18% of a group of 174 young female Filipino nurses ranging in age from 20 to 25 years and working at the American University of Beirut Medical Center (AUMC) were found susceptible to the varicella-zoster virus; as compared to 3% of a matched group of 133 of their Lebanese colleagues. The level of antibody was determined by the Enzyme Linked Immunosorbent Assay (ELISA). Those susceptible were assigned duties in low-risk areas to varicella-zoster in the hospital.

Pseudomonas cepacia was first reported in the literature by Burkholder as a phytopathogen responsible for sour skin, a disease of onion bulbs. Similar bacteria were isolated from other sources and given various names including Pseudomonas multivorans, Pseudomonas kingii, and EO-1. The synonymy of these organisms with P. cepacia was eventually established. The first descriptions of human disease due to Pseudomonas cepacia were two reports of infective endocarditis. Subsequently, a series of postoperative urinary tract infections secondary to contaminated disinfectant solution were reported and P. cepacia became identified as a cause of nosocomial infection. P. cepacia has demonstrated a low level of virulence and invasiveness in the general population, but it has been shown to cause severe infection in patients with underlying diseases. Moreover, its nutritional versatility and ability to survive in antiseptic solutions make it a superb agent for causing hospital-acquired infection.

Nosocomial infection rates, as determined by either incidence or prevalence methods, are considered important data in infection control programs. Many factors besides infection control measures affect infection rates— eg, illness acuity of the patient population. However, there is evidence that when these factors remain constant, a lowering of the infection rate can be the result of infection control efforts. We wish to illustrate how a dramatic drop in infection rate may mislead infection control personnel into a false sense of accomplishment, when in reality it is an effect of changing medical practices.

As we have become experienced in dealing with AIDS, we have learned that early concern over employees who refuse to care for patients with AIDS was merely the tip of the iceberg from the infection control standpoint. During the past 5 years, additional questions and concerns have been raised regarding employee health and AIDS. An interesting body of literature has emerged recently that discusses many of these current employee health issues. Some of these questions have been answered in major communications in The New England Journal of Medicine, the Journal of the American Medical Association, and The Lancet. Many other topics have been covered in short communications in letters to the editor in these same journals and in the CDC's Morbidity and Mortality Weekly Report (MMWR). When taken together, this writing presents a very clear picture of what is happening with AIDS in the health care arena. It is obvious that most of the concerns regarding AIDS in health care settings can be answered by taking a close look at the available epidemiologic data. It is important to remember that the decision-making process related to AIDS is easier if we try to separate the emotional issues surrounding the disease from the scientific data available.

Since the introduction of hepatitis B immune globulin (HBIg) and more recently, the hepatitis B vaccine, programs for hepatitis B prevention have become a major part of most employee health/infection control programs. In fact, hepatitis B prevention activities have probably been responsible for increased collaboration between the two programs. Hepatitis B prevention is a very fluid process and is constantly changing as we develop a greater understanding of the creative uses of both HBIg and the vaccine. On e important trend that has emerged from the introduction and widespread use of HBIg and vaccine has been a greater emphasis on pre-exposure prevention of hepatitis B infection. In the past, programs for hepatitis B prevention consisted of periodic hepatitis B screening in dialysis units and some laboratories. Unfortunately, screening only monitors introduction of infection and does very little to prevent hepatitis B virus (HBV) infection.

Viral hepatitis B is one of the major concerns of today's healthcare workers. Of the 100,000 Americans infected each year, 5% to 10% of them are employed in healthcare professions. For every 500 identified high-risk personnel, as many as 50 could become infected with hepatitis B virus. Every hospital should have procedures in writing for pre- and post-exposure prevention of hepatitis B.

Over a 7-year period (1978-1984) the authors studied the rates of nosocomial bloodstream infections in acute-care hospitals participating in a statewide surveillance network in Virginia. A total of 4,617 hospital-acquired bloodstream infections were documented among 1,807,989 patients at risk for an overall rate of 25.5 cases per 10,000 patient admissions/discharges (annual range = 22.1 to 30.7). Compliance of reporting for Virginia hospitals averaged 58% (1 to 5 monthly reports in a study year), and 39% (≥6 monthly reports annually). Significant changes in bloodstream infection rates (cases per 10,000 patient admissions/discharges) due to specific pathogens included the following: coagulase-negative staphylococci increased from a rate of 1.3 to 4.5 (P=.0003), and those due to all gram-positive cocci increased from a rate of 7.5 to 11.4 (P=.03). Candida species increased from a rate of 0.1 to 1.5 (P=.005). The data show a continuing rise of nosocomial Candida BSI and clearly document the re-emergence of gram-positive cocci as major nosocomial bloodstream pathogens.

The “second” and “third” generation cephalosporins offer striking antimicrobial activity against a wide spectrum of Enterobacteriaceae. Nevertheless, mutants resistant to these drugs have emerged in both laboratory and clinical settings. For example, before the commercial availability of the third-generation agents, we treated three cardiac surgery patients for Enterobacter mediastinitis with aminoglycosides and high doses of cefamandole. In two, initial treatment failed due to emergence of strains that were not only resistant to cefamandole, but also to then experimental third-generation drugs. Despite such reports and in vitro studies of the mechanisms of resistance, the frequency with which broad-spectrum cephalosporin resistance develops in clinical practice is not clear. To help delineate this problem, we have reviewed our hospital's experience with Enterobacter strains resistant to newer cephalosporins (using cefamandole and cefotaxime as prototypes) and the relation of resistant strains to cephalosporin use, with special attention to our cardiac surgery patients.