We compared the antibiogram statistics generated by including all clinical isolates to those obtained by tabulating no more than one isolate of a particular organism from a given patient. We found that 48.3% of the isolates presented multiple occurrences in individual patients but found no practical differences in the profiles obtained by the two methods. We also tabulated the occurrence of minimum inhibitory concentration (MIC)-distinct organisms among the sets of multiple isolates of E. coli and of S. aureus and found that only 20.9% of those isolates represented duplicate organisms by MIC profile. This heterogeneity of MIC sensitivity that occurs in multiple isolates from individual patients was not expected but provides an explanation for the lack of difference between the two methods of tabulating antibiotic susceptibility statistics.

A bacteriological study was completed on pools and whirlpools operated by hotels and private health clubs in the metropolitan area of Toronto, Ontario, Canada. Coliform bacteria, fecal coliform bacteria, and fecal streptococci were found only when other indices showed a drastic deterioration in water quality. Aerobic plate counts were higher, and staphylococci and Pseudomonas aeruginosa occurred more often in whirlpools than in swimming pools. There was a correlation between aerobic plate counts and the presence of staphylococci and P. aeruginosa. P. aeruginosa was rare in swimming pools in the absence of staphylococci; however, in whirlpools the organism was often found in the absence of staphylococci, and when aerobic plate counts were low. P. aeruginosa and plate counts in excess of 3,000 per ml occurred more frequently in whirlpools when the free chlorine residual was less than one part per million. The surface film showed concentrations of staphylococci far greater than the pool water. Whirlpools appear to present a different ecosystem that favors the establishment of P. aeruginosa. Staphylococci, but not Staphylococcus aureus, are useful in indicators of pool water quality but better laboratory methodology is required. Additional attention should be directed to the bacteriology of the water surface film, which presents a more direct hazard to bathers.

Primary infections caused by Klebsiella species are uncommon, but the organism is an important nosocomial pathogen. We report the predisposing factors, clinical features and outcome of 44 hospitalized patients in whom Klebsiella oxytoca was isolated. Twenty-one (48%) isolates were community-acquired and 23 (52%) were considered nosocomial in origin. Most of the patients were elderly males with serious underlying diseases. There were significant differences between those patients who acquired Klebsiella oxytoca in the hospital and in the community. Nosocomially acquired organisms were associated with a higher mortality (52% vs. 24%) (p<0.05), a higher incidence of infection vs. colonization (83% vs. 57%) (p<0.05), and a higher percentage of cases of pneumonia (43% vs. 19%) (p<0.05). The clinical features, the hospital service and the patients' underlying diseases were similar when patients who died and those who survived were compared. Patients who died were exposed to antibiotics more often prior to the positive culture with K. oxytoca (p<0.05). K. oxytoca is a significant pathogen in hospitalized elderly patients. It is likely to cause infections, especially pneumonia, and carry a high mortality. The organism can become endemic within the hospital setting with continued carriage and nosocomial spread.

The third-“generation” cephalosporin antibiotics (Table 1) represent a class of agents with an expanded gram-negative spectrum of activity beyond that of the first- and second-“generation” cephalosporins. Greater stability to beta-lactamases produced by gram-negative organisms confers to these agents a greater bactericidal action against the Enterobacteriaceae. Large bacterial inocula (105/ml) in vitro significantly increase the minimum inhibitory and bactericidal concentrations (MIC and MBC) explaining treatment failures with these agents in infections associated with large numbers of organisms. The pharmacokinetic features of some of the agents allow prolongation of dosing intervals, and enhanced tissue penetration amplifies their clinical utility in infections distant from the bloodstream (eg, meningitis).

The genus Enterobacter belongs to the tribe Klebsielleae found in the family Enterobacteriaceae. Members of this genus had previously been referred to as Aerobacter. The clinical importance of this genus as a separate entity was not fully appreciated until the 1960s. Until that time, the differentiation of Enterobacter from Klebsiella was not routinely performed, which resulted in many infections reported as being caused by the Klebsiella-Aerobacter group. Added confusion occurred at this time with the taxonomy change of Aerobacter to Enterobacter.

In 1911, McCoy discovered an unusual illness among ground squirrels in Tulare County, California. The illness resembled plague but was clearly different because a pathogen could not be isolated on the usual culture media. With the addition of egg yolk to the media, McCoy finally isolated an organism and named it Bacterium tularensis. It was soon recognized that B. tularensis could cause disease in humans, and many investigators, especially Edward Francis, did much of the early work defining the bacteriology, pathology, and epidemiology of tularemia. The name of the organism was eventually changed to Francisella tularensis in honor of Francis.

Unlike Pseudomonas aeruginosa and the Enterobacteriaceae which are relatively non-pathogenic in the normal host, F. tularensis can easily cause disease in previously healthy persons. In contrast, F. tularensis has not been implicated in nosocomial infections and person to person spread is rare. The organism is, however, extremely hazardous to workers in the clinical microbiology laboratory. Of all common bacterial and fungal pathogens isolated in the clinical laboratory, F. tularensis is second only to Coccidioides immitis in its potential to infect the laboratory worker. Many experienced investigators claim that it is impossible to work with the pathogen for any length of time without becoming infected. Currently it is highly recommended that persons who routinely work with the organism be immunized.

To estimate the risk of hepatitis B virus (HBV) infection among hospital workers, we measured the prevalence of HBV infection in employees in five hospitals in different parts of the country and examined the effect of occupational and non-occupational factors on HBV prevalence. Among 5,697 persons studied, serologic markers of HBV infection were found in 807 (14%). Prevalence of infection was strongly related to race (Asian > Black > White), sex (male > female) and increasing age.

Risk related to health occupation, studied by examining the change in HBV prevalence with duration in occupational group, was most strongly correlated with frequency of contact with blood during work. Workers having frequent blood contact had the highest estimated infection rate (1.05 per 100 person-years) and those with moderate contact an intermediate infection rate, compared to a negligible infection rate in workers with no blood contact. Frequency of needle accidents had an independent, positive effect on HBV infection rates, while degree of patient contact had no effect. Infection risk was uniform among all hospitals for groups with frequent blood contact. Among different occupation groups, risk of HBV infection also correlated closely with degree of blood-needle contact during daily work. This study provides a general approach to assessing risk of HBV infection in hospital personnel, and indicates that risk may be most easily estimated by quantitating degree of blood-needle contact during daily work.

In a recent communication, the manufacturer of a glutaraldehyde-based disinfectant described several important discoveries that became apparent during a recent review of claims of their product. Such updating of materials is an ongoing quality assurance mechanism for many reputable manufacturers.

Manufacturer A maintains that the old Association of Official Analytical Chemists (AOAC) tuberculocidal testing procedure is prone to significant errors. Therefore, they developed a new, more reliable test (in their opinion), which has also been filed with the Environmental Protection Agency (EPA), and on which their new recommendations are based. Other manufacturers may use the old or new AOAC test methods to satisfy requirements of the EPA.

High temperature bathing in hot tubs, spas and whirlpools poses four potential public health concerns: injury/death, disease transmission, possible teratogenic effects, and congestive heart failure or dysrhythmias for individuals with cardiac problems. Health departments need criteria before initiating environmental and epidemiologic investigations. These criteria must include severity of the disease and number of individuals possibly exposed. In addition, public health officials are obligated to define the magnitude of the problem, inform affected individuals and institute appropriate control measures. Optional information should be collected during an environmental and epidemiologic investigation to clarify the mechanisms of disease transmission and design control measures. The public health response to improving hot water bathing safety and sanitation should be directed at primary prevention. Educational efforts would be directed toward whirlpool operators, users and the medical community. Included should be a review of regulations addressing the construction and operation of public spas and whirlpools.

In July 1982, five Hartford hospitals embarked on a joint hospital-sponsored program to immunize high-risk employees against hepatitis B virus (HBV). The program included a questionnaire to characterize relative risk, serology for anti-HBs, vaccination and a follow-up survey of vaccine non-recipients.

Of 2,065 employees who were considered to be at high-risk for infection with HBV, 1,894 (91.7%) responded to the screening questionnaire and 1,279 (67.5%) were tested for anti-HBs serology. The prevalence of antibody varied from hospital to hospital; the highest prevalence (10.9%) was observed at one of the urban university-affiliated community hospitals and the lowest prevalence (4.1%) was reported from the smaller, rural hospital. The prevalence of antibody also varied greatly within the high-risk groups; the highest prevalence of antibody was seen among surgical house officers (15%). The rate of acceptance of vaccine among hospitals ranged from 57.5% to 23.7%. Reasons for vaccine non-acceptance included fear of as yet unknown side effects, perceived low risk of hepatitis acquisition and possible effects on present or future pregnancies.

Our experience illustrates some of the epidemiologic and practical aspects that must be addressed in administering a hospital-based HBV vaccine program. Among the five hospitals, we saw marked inter- and intra-hospital variations in the prevalence of anti-HBs among high-risk employees. More significantly, we observed unexpectedly low rates of vaccine acceptance among high-risk personnel.

Results with a VZV skin test as a marker of past infection were compared with histories of chicken pox and specific antibody detected by ELISA in 100 individuals—25 of whom were pediatric patients with malignant diseases. A negative or uncertain history was not reliable, neither were the skin test results among the oncology patients. However, among the normal individuals, the skin test when compared with the ELISA had a sensitivity of 85%, a specificity of 100%, and a positive predictive value of 100%.

Recent advances in our knowledge of the Acquired Immune Deficiency Syndrome (AIDS) could have a major impact on practitioners in both infection control and employee health. The discovery that a retrovirus, the human T-cell leukemia virus (HTLV-III) is the cause of AIDS could be used to help health care workers better understand this disease. Those of us who are trying to provide our employees with up-to-date information on AIDS should use this new information to help employees understand the nature of the disease, its transmissibility and non-transmissibility. Now that the disease can be linked to a specific agent, employees may find AIDS to be much less mysterious. The retrovirus link is a major step forward in understanding this disease and may eventually lead to more effective treatment and possibly a vaccine. Our knowledge continues to evolve in much the same way as our understanding of Legionnaires' Disease and Toxic Shock Syndrome.

The Acquired Immune Deficiency Syndrome (AIDS) was discussed extensively at recent infectious diseases meetings in Washington, D.C. The results of original research conducted by investigators at the National Institutes of Health (NIH), Centers for Disease Control (CDC), Pasteur Institute in Paris, and medical centers throughout the world were presented at the meetings. A number of issues have been clarified and the pieces of the puzzle are starting to come together.

Not long after the introduction of penicillin G for anti-staphylococcal therapy, penicillin G resistant strains of staphylococci were isolated and were found to produce penicillinase enzymes. In 1959 methicillin, a penicillinase resistant penicillin (PRP), was introduced in England for therapy of these strains. Within 2 years the first strains of methicillin-resistant Staphylococcus aureus (MRSA) were reported in that country. Subsequently, reports of MRSA infections throughout Europe appeared. Reports from Switzerland and Denmark indicated that 30% to 50% of all nosocomial S. aureus isolates and 40% of all S. aureus bacteremia isolates, respectively, were due to MRSA. Although sporadic reports of MRSA infections appeared in the US after 1960 the first documented outbreak of MRSA infections occurred at Boston City Hospital in 1968. Even today there is not a complete understanding of MRSA and its role in infectious diseases, however, a vast amount of information has accumulated and certain aspects of this information will be discussed.

Under prospective payment utilizing the diagnostic related groups (DRG) classification, hospital administrators have begun to rethink accepted hospital procedures. It is now necessary to consider every factor that contributes to the cost of care, because those costs will be borne more and more by the hospital rather than the patient. Administrators must determine if an expenditure really improves the quality of care and shortens the length of stay. Unfortunately, in many cases there are no mechanisms or criteria for such an evaluation. The health care industry is in danger of cutting away tissue when the fat is being trimmed away. An effort tojustify and quantify the benefit of an infection control program in a 270-bed acute care general hospital led to eye-opening results, and a decision to expand the program rather than reduce it. The expanded program is expected to recover cost two-fold.

Over a period of 35 days beginning July 23, 1984, the Infection Control Section of the Nassau Hospital, a 535-bed community teaching institution received reports of an unusually high number of PPD tuberculin skin test conversions among employees from Employee Health Service personnel.

The first case involved a registered nurse who, upon receiving a routine annual Mantoux skin test on July 23, converted from the previous year's negative reaction to a significant reaction (20 mm induration) with a greater than normal area of erythema. When she reported this to her private medical doctor prior to beginning INH prophylaxis, she was retested by the physician. This test was read as nonreactive.