Recurrent group A streptococcal carriage in a health care worker associated with widely separated nosocomial outbreaks.

Nine postpartum infections (five bacteremias, three cases of endometritis without bacteremia, and one infected episiotomy site) caused by an M-nontypable, T-28 strain of group A Streptococcus occurred during a 9-week period in 1987. Seven cases were cared for by one obstetrician, who was also present in the delivery suite when the remaining patients delivered. This individual was found to be an anal carrier of group A Streptococcus with the same M and T types. During the cluster, the attack rate for vaginal deliveries performed by this individual was 18% (6 of 34 patients). The individual was treated with penicillin V (500 mg four times a day for 10 days), rifampin (600 mg twice a day for 5 days), and hexachlorophene showers. Surveillance cultures of the physician were negative 1 week, 1 month, and 3 months after completion of therapy. No additional cases were identified among the next 210 vaginal deliveries performed by this individual. Fourteen months after therapy, four new cases occurred during 2 days. The physician was found to be heavily colonized once again with the original strain of group A Streptococcus and was treated with rifampin (600 mg twice a day) and oral vancomycin (250 mg four times a day) for 7 days. An open-ended regimen of penicillin V (250 mg/day) and periodic surveillance cultures was begun. During the next 19 months, this physician performed 275 vaginal deliveries, one of which resulted in an M-nontypable, T-28 group A streptococcal infection, at a time when the physician's surveillance cultures were negative. It is unclear how long a colonized health care worker who causes nosocomial group A streptococcal disease must be treated or monitored, but there is some risk after more than a year. Long-term surveillance or prophylaxis may be useful in some circumstances.

Monitoring steam sterilization of surgical instruments: a dilemma.

The study of two biological indicators in monitoring "flash" sterilization demonstrated that indicator construction often leads to a false interpretation of spore survival.

Prevalence and survival of microbial contaminants in heated nebulizers.

Over a 2-year period, 600 cultures of fluid in heated nebulizers in use by patients in the Peter Bent Brigham Hospital were performed. The most commonly isolated microorganisms were Pseudomonas and Alcaligenes species. Pseudomonas aeruginosa was never isolated. Three types of heated nebulizers were in use, and their contamination rate was significantly different (45 percent, 21 percent, and 8 percent, respectively; p less than 0.001). In the course of the study, the overall contamination rate decreased from 47 percent to 10 percent. This was mainly due to elmination of the type of heated nebulizer that was most prone to contamination. Five types of currently available large-reservoir nebulizers were inculated with various organisms and growth patterns studied. The various nebulizing equiment differed in its ability to inhibit or eliminate microbial growth; 1 of the heated nebulizers appeared to enhance growth of some of the inoculated bacteria.

Microorganisms in heated nebulizers.

Out of 353 heated nebulizers in actual use which were cultured in the Peter Bent Brigham Hospital, 118 (33%) were found to be contaminated. Gram-negative organisms predominated with rare micrococci and fungi. A slow-growing Vibrio was also recovered from 4 nebulizers. Heating of nebulizers above 46 C resulted in significant reduction of contamination. Types of heated nebulizers also figured significantly in the rate of contamination found. Carefully considered recommendations for the care and use of respiratory therapy equipment must be instituted and enforced. Techniques for terminal disinfection of equipment, followed by sterilization should result in the issue of sterile equipment for each patient. Rules for maintenance of equipment at the bedside are also needed.