Legionnaires' disease caused by Legionella dumoffii in distilled water.

Five cases of Legionnaires' disease caused by Legionella dumoffii were identified within an 11-month period in a hospital in the Quebec City area. In four cases bacterial isolates were obtained from clinical specimens, and in one case seroconversion was demonstrated. All the patients had been admitted to hospital within 10 days before diagnosis. Two of the patients were immunosuppressed children. Only 1 of the 40 hot water samples from the hospital yielded L. dumoffii; however, 6 of 11 distilled water samples contained the bacterium. All the patients had been exposed to distilled water, four through respiratory therapy equipment and one through a room humidifier. Following the use of sterile distilled water in the apparatus, no further cases were identified. This is the first reported outbreak of Legionnaires' disease caused by L. dumoffii, and it is the first time that nosocomial legionellosis has been linked to contaminated distilled water in Canada.

Food-borne botulism in Canada, 1971-84.

Sixty-one outbreaks of food-borne botulism involving a total of 122 cases, of which 21 were fatal, were recorded from 1971 to 1984 in Canada. Most occurred in northern Quebec, the Northwest Territories or British Columbia. Of the 122 victims 113 were native people, mostly Inuit. Most of the outbreaks (59%) were caused by raw, parboiled or "fermented" meats from marine mammals; fermented salmon eggs or fish accounted for 23% of the outbreaks. Three outbreaks were attributed to home-preserved foods, and one outbreak was attributed to a commercial product. The causative Clostridium botulinum type was determined in 58 of the outbreaks: the predominant type was E (in 52 outbreaks), followed by B (in 4) and A (in 2). Renewed educational efforts combined with a comprehensive immunization program would significantly improve the control of botulism in high-risk populations.

Antimicrobial susceptibilities of coagulase-negative staphylococci isolated from urinary infections.

The susceptibilities of 107 urinary isolates of coagulase-negative staphylococci to 19 antibiotics was determined by an agar dilution technique. Major differences in the antimicrobial susceptibilities of species of coagulase-negative staphylococci were observed. Staphylococcus epidermidis was more resistant to a wider spectrum of antibiotics than was Staphylococcus saprophyticus.

Comparative in vivo efficiency of cefamandole and cefoxitin against Bacteroides fragilis.

An experimental model, where fibrin clots were inserted subcutaneously in rabbits, was adapted to study the in vivo efficacy of two cephalosporins against Bacteroides fragilis. The respective MIC's of cefamandole and cefoxitin against the microorganism were 16 microgram/ml and 1 microgram/ml. The clots were infected with 10(7) B. fragilis. Groups of seven animals received an intravenous bolus injection (100 mg/kg) of either drug. The serum levels of both drugs were similar to those seen in humans. The peak concentrations of cefamandole (40 microgram/mg) in the clots were found to be ten times higher than those of cefoxitin (4 microgram/mg). The log number of colony forming units in the clots averaged 7.5 at 0 h. At 6 hours, this number reached 8 in the untreated animals, 1.5 after cefoxitin, and 1.7 after cefamandole. The apparent in vitro superiority of cefoxitin against B. fragilis could not be demonstrated in vivo. This discrepancy between in vitro and in vivo data can be explained by the high degree of penetrance of cefamandole into the infected fibrin loci. In this animal system, both cefoxitin and cefamandole had similar in vivo activity against B. fragilis.

Penetration of cefamandole, cephalothin, and desacetylcephalothin into fibrin clots.

The conversion of cephalothin into a less active metabolite (desacetylcephalothin) might influence its distribution in tissues. An experimental rabbit model devised to determine concentrations of antibiotics in subcutaneous fibrin clots was used in this study. Groups of five to six animals received 100-mg/kg intravenous injections of either cefamandole or cephalothin. One hour after the injection, the concentration of cefamandole in serum was 20 times higher than that of cephalothin. Whereas cephalothin was undetectable at 4 h, cefamandole was still detectable at the end of the experiment. The half-lives of cephalothin and cefamandole in serum were 16 and 27 min, respectively. The concentration of cefamandole found in fibrin clots was severalfold higher than that of cephalothin. The half-life of cefamandole in clots (81 min) was superior to that of cephalothin (38 min). Although concentrations of both antibiotics were higher in serum than in clots at 1 h, the concentrations of these drugs in the clots persisted at higher levels throughout the next 5 h of the experiment. The extent of binding of cefamandole (87%) to rabbit serum was greater than that of cephalothin (50%). At least 55% of cephalothin was metabolized in vivo into its less active metabolite desacetylcephalothin. This metabolite was found in higher proportion in the serum (75%) than in the clots (55%). Whereas only 12% of the free (unbound) cephalothin reached the clots, 78% of the free cefamandole was found in the clots. This lower level of penetration of unbound cephalothin might be explained by the short half-life of this antibiotic, not permitting equilibrium to occur.

[Diphtheria epidemic occurring on the North Shore of the St. Lawrence River in the fall of 1974]. / Epidémie de diphtérie survenue sur la Côte Nord du St-Laurent à l'automne de 1974

An outbreak of diphtheria occurred on the North Shore of the St. Lawrence River at the beginning of September 1974. It started with the death of an 18-year-old forest worker Sept. 5, spread over a vast area of the North Shore and lasted until the end of October that year. Eleven strains of toxigenic Corynebacterium diphtheriae intermedium, type K were isolated. Eleven of the 12 patients had characteristic diphtheritic pharyngitis with pseudomembranes. Preventive measures, set forth immediately after the third case was declared, included the following: (a) daily surveillance of all contacts, (b) isolation or preventive hospitalization of persons with all types of pharyngitis, (c) mass vaccination of all susceptible persons and (d) search for healthy carriers of the germ. No strains of toxigenic C. diptheriae were isolated from patients preventively hospitalized or from the 1235 individuals among whom carriers were sought. Among the main characteristics of this epidemic, the mean age of the patients (17 years), their mobility and their habits are factors that could have made it almost uncontrollable. It is also remarkable that this outbreak occurred in such a scattered population of adolescents, in 82% of whom the Schick test was negative.