How frequent are outbreaks of nosocomial infection in community hospitals?

A statistical algorithm was used to identify potentially important clusters among nosocomial infections reported each month by 7 community hospitals. Epidemiologic review and on-site investigations distinguished outbreaks of clinical disease from factitious clusters. In 1 year, 8 outbreaks were confirmed. They involved 82 patients--approximately 2% of patients with nosocomial infections and 0.09% of all discharges. One true outbreak occurred for every 12,000 discharges--at least 1 outbreak per year for the average community hospital. Five (63%) outbreaks were recognized independently by the hospitals' infection control personnel. Four (50%) resolved spontaneously; the hospitals' own control measures were necessary in 2; and 2 resolved only after an outside investigation. Organized surveillance appears necessary to detect some outbreaks, and control measures are needed to stop many. Since, however, outbreaks account for such a small proportion of nosocomial infections, infection control programs should be sufficiently staffed and managed so that most of the effort is directed toward the surveillance and control of endemic infection problems, but with adequate resources remaining to respond to outbreaks when they occur.

An examination of the microbiologic flora of normal lung of the dog.

We examined the hypothesis that normal lung is sterile. A laboratory animal, the dog, was chosen so that sample size could be maximized. Controls were used to eliminate the possible artifactual presence of bacteria in the lung. Thirty-seven per cent of lung samples contained aerobic bacteria with a mean concentration of 1.3 X 10(3) organisms per g of tissue. Seventy-four per cent of identical bacterial isolates were found in the pharynx of the same animal. We concluded that viable bacteria are aspirated into normal lung where they may survive for at least limited intervals.

Nosocomial infection with highly resistant, Proteus rettgeri. Report of an epidemic.

Over 22-1/2 months an epidemic of at least 127 cases of nosocomial infection developed from a strain of Proteus rettgeri resistant to all antibiotics commonly tested in hospital laboratories. Although there were at least four cases of septicemia and one related death, the majority of cases consisted of asymptomatic bacteriuria or clinically mild urinary tract infection. Indwelling urinary tract devices and antibiotic therapy were important predisposing factors. Data supported an association between increasing use of gentamicin and increasing rates of resistant infection. No common source was found, and contact spread appeared more likely. Control measures included efforts to reduce unnecessary exposure to the incriminated risk factors and to improve asepsis in the management of catheterized patients. An additional 36 cases and one related death were identified in the 7-1/2 months following the investigation and institution of control measures. Nosocomial infection with extremely resistant organisms may pose a serious hazard wherever indwelling urinary tract devices and antibiotics are used together intensively.

An outbreak of nosocomial Proteus rettgeri urinary tract infection.

Between December 1, 1971, and November 30, 1972, 11 patients on a single physical rehabilitation ward in a large St. Louis, Missouri, community hospital developed Proteus rettgeri urinary tract infections; P. rettgeri isolates from each patient were indole-negative and resistant in vitro to all antibiotics tested. Infected patients were more likely to have indwelling urinary tract catheters than were matched control patients, and all had previously received systemic antibiotic therapy. Retrospective epidemiologic investigation and microbiologic samplig at the time of the investigation failed to detect a common source of infection. Infected patients appeared to be the major reservoir of the epidemic strain, and indirect-contact transmission of the organism via nursing personnel probably occurred. Data collected from a prospective study suggested that placing catheterized patients in rooms that did not contain other catheterized patients may be an effective control measure.