This article describes a prolonged outbreak (January 1977 to February 1980) of amikacin-resistant Serratia marcescens (ARSM) urinary infections and the methods used for its control. Significant factors predisposing to ARSM urinary tract infection included an extended hospital stay, being in the urology ward, and undergoing urologie surgery. There had been no prior administration of amikacin or of other aminoglycosides in 20 of 27 patients with ARSM urinary tract infections. Chronically infected patients who required multiple hospitalizations represented a major reservoir for the perpetuation of the outbreak, overshadowing the importance of aminoglycoside use. Traditional control measures and even a major change in the inanimate environment were only partially effective in controlling the outbreak, but treatment of bacteriuric patients in the urology unit with “second and third generation” cephalosporins interrupted patient-to-patient transmission. No new cases of ARSM bacteriuria appeared in the urology unit in the ensuing 12 months [Infect Control 1981; 2(5):367-372.]

The possibility of sepsis or pyrogenic reaction increases in hemodialysis patients as coliform or other gram-negative counts in the dialysis water reach levels ≥ 1000 colonies/ml. After the introduction of Cobe Century II dialysis machines (Cobe, Lakewood, Colorado), routine testing of dialysis water samples revealed gram-negative bacteria in concentrations up to 45,000 colonies/ml. An epidemiologic investigation was performed to determine the source of the bacterial contamination. The amounts of disinfectant solution were increased, but bacterial counts remained unacceptably high. A study of the fluid path within the machines revealed that part of that path was not reached at all by the disinfectant. In addition, the disinfectant was automatically and improperly diluted. Therefore, increased bacterial counts could not be reduced satisfactorily by using the manufacturer's disinfection guidelines.

Microbiologic surveillance of both the patients and the ambient environment of a surgical intensive care unit allowed us to relate the incidence of nosocomial respiratory tract infection to levels of airborne bacteria. Over the study period respiratory tract nosocomial infection rates varied from 0.7% to 17.0%, and nonrespiratory infection rates varied from 1.0% to 25.0%. Airborne bacteria counts during that time varied from 1.0 ± 0.8 S.E. CFU/ft3 to 96.0 ± 6.8 S.E. CFU/ft3. There was a reasonably close correlation between airborne bacteria levels and the incidence of nosocomial pneumonia (r=0.81, p<0.05). Furthermore, there was a close correlation between a specific organism nosocomial infection rate and the number of colonies of that organism present in the air (r=0.88, p<0.05). In contrast, there was no significant relationship between airborne bacteria counts and nonrespiratory attack rates (r=0.60, p<0.05). If the bacteria traveled from the air to the patients, there appear to be at least three possible explanations for this significant relationship: (1) direct inoculation of the airway by the airborne bacteria; (2) inoculation of the airway by direct contact, which is related to the degree of “cleanliness” of the environment; and (3) an increased incidence of contaminated respiratory equipment and airway inoculation because of high counts of airborne bacteria. It is also possible that high bacterial air counts represent contamination of the air from patients with respiratory infections. Regardless of the pathway(s), surveillance of the ambient environment may prove to be a useful epidemiologic tool in the study and control of nosocomial respiratory tract infections in certain high-risk patient care areas.

Research leading to the development of Sporicidin, a new (synergized glutaraldehyde-phenate) sterilant and concentrated disinfectant, is reported. Microbial evaluation and shelf life testing of the new formulation was done using AOAC tests—Use-Dilution, Sporicidal, Tuberculocidal—and the E.P.A. Virucidal Test. Full-strength Sporicidin sterilizes (is sporicidal) in 6% hours at both 20C and 25C, and disinfects in 1-2 minutes. When diluted with 15 parts of tap water, Sporicidin is tuberculocidal, virucidal, and germicidal in 10 minutes, qualifying as a hospital disinfectant that will not “yellow” the hands or skin. The shelf life of activated Sporidicin, full strength or diluted 1 in 16, is 30 days. According to the data presented, which were the basis of E.P.A. registrations, Sporicidin is: (a) the fastest glutaraldehyde sterilant at room temperature, and (b) the only glutaraldehyde product that can be diluted below 2% and still qualify as a hospital disinfectant.

Persistent hepatitis B infections among patients and frequent new hepatitis B infections among both patients and staff were a major problem in our dialysis unit during its first two and one-half years of operation. During this time the mean quarterly rate of conversion to HBsAg positivity among patients ranged from 0-60% (mean 12%); in staff it ranged from 0-13%. Control efforts, including strict temporal isolation, improved sanitary measures, and use of parallel plate dialyzers without geographic or machine isolation, were begun late in 1976. After a four-month lag, new HBsAg conversions ceased among the 30 patients and staff at risk, despite continued dialysis of eight HBsAg-positive patients (at least four of whom were HBeAg-positive). Over the succeeding three years the conversion rate was zero in both patients and staff. This experience suggests that conservative control measures without geographic separation of patients may be sufficient to control an established outbreak of hemodi-alysis-related hepatitis B. Controlled prospective trials of this hypothesis are warranted.

Prospective surveillance of 1,527 episodes of bacteremia in the four major hospitals serving a community of 300,000 revealed striking differences among the hospitals. The rate of community-acquired bacteremia ranged from 1.9 to 6.8 per 1000 discharges; the rate of nosocomial bacteremia ranged from 0.9 to 9.8 per 1000 discharges. Death rates attributed to nosocomial bacteremias varied among the hospitals by as much as 40-fold. Nosocomial bacteremias were less frequent at two community non-teaching hospitals than at two teaching hospitals. Although fewer blood cultures were obtained at the nonteaching hospitals, the ratio of blood cultures obtained to deaths attributed to bacteremic infection was highest at these hospitals, suggesting that physicians recognized the importance of obtaining blood cultures in critically ill patients. The potential usefulness of bacteremia surveillance is reviewed. It is suggested that hospitals serving a single community might constitute an appropriate unit for such surveillance [Infect Control 1981: 2(3):219-226.]

During a 1979 outbreak of poliomyelitis in Lancaster County, Pennsylvania, we investigated the neccessity for and the response to booster vaccination of hospital personnel. The immune response of hospital employees who received booster injections of Salk vaccine (n=38) was compared with that of residents in the surrounding community who received Sabin trivalent OPV boosters (n=43). Serum neutralizing antibody titers to the three polio serotypes were measured before and after booster immunization. Results indicated that 38% of the subjects in both groups had low initial antibody titers. Salk vaccine was in all circumstances as effective or better than Sabin vaccine in increasing neutralizing IgG antibody titers [Infect Control 1981; 2(5):377-379.]

During a hospital epidemic of infections with gentamicin-resistant Serratia marcescens (GRS), we studied the relation between receiving antibiotics and acquiring GRS. In a five-month period, 22 patients acquired GRS, whereas 18 patients acquired gentamicin-sensitive Serratia (GSS). When compared with patients with nosocomial GSS infection, patients with nosocomial GRS had been in the hospital (p = 0.04) and the intensive care unit (p = 0.003) longer before infection and more had received gentamicin (p = 0.001) or ampicillin (p = 0.02) before infection. To control for the influence of underlying disease, we matched all 12 ICU patients with GRS infection and 12 patients without GRS infection for underlying illness and duration of intensive care. Use of any antibiotic (p = 0.04), or a combination of gentamicin plus ampicillin or cephalosporin (p = 0.047) was more common among patients with GRS infection. The hospital had not significantly increased the use of aminoglycosides from the previous year. We conclude that for the individual patient antimicrobial therapy, especially with gentamicin or ampicillin, creates a risk for later infection by GRS that is independent of the severity of the underlying illness.

A limited survey of 90 orthopedic surgery programs throughout the U.S. A. was conducted to determine the use of prophylactic antibiotics in pediatric orthopedic operations. Prophylaxis was used most often in the Harrington rod procedure (80.7%); less often in hip (64.2%) and knee (44.7%) reconstructive surgery; rarely in meniscus repairs (8.0%) and in lengthening of Achilles tendǫns (2.3%). Cephalosporins (85%) were the antibiotics prescribed most frequently. The first dose was administered before surgery in 89.6% of the operations. Prophylaxis was discontinued within five days in 96% of the operations. These data provide a pattern of the use of prophylaxis in pediatric orthopedic surgery.