A Congo red-magnesium oxalate agar medium was developed to detect expression of virulence-associated calcium dependency and Congo red absorption in Yersinia enterocolitica. Of the 157 pathogenic serotypes tested, 119 (75.8%) were positive; 98% of nonpathogenic serotypes and strains of three other Yersinia species were negative.

Yersinia enterocolitica has emerged as an enteropathogen associated with several types of human infections that often require antimicrobial therapy, but little is known about the antimicrobial susceptibilities of pathogenic strains isolated from humans in Canada. To determine the present patterns of antimicrobial susceptibility, to identify changes in these patterns that occurred during the past two decades, and to investigate the relationships between 0 serotypes and patterns of susceptibility, we tested a total of 1,105 pathogenic Y. enterocolitica strains isolated during 1972 to 1976, 1980, 1985, and 1990 for their susceptibilities to 22 antimicrobial agents. Susceptibility testing was performed by using a single breakpoint concentration in agar procedure. The results showed that all strains were susceptible to ciprofloxacin and piperacillin, and 98% or more of the strains from each period were susceptible to trimethoprim, sulfamethoxazole, cotrimoxazole, tetracycline, chloramphenicol, cefamandole, cefotaxime, aztreonam, and four aminoglycosides. In contrast, all strains were nonsusceptible to erythromycin, furazolidone, and clindamycin and 90S% or more of the strains from each period were nonsusceptible to ampicillin, carbenicillin, ticarcillin, and cephalothin. Strains belonging to serotypes 0:3, 0:5,27, and 0:8 had different patterns of susceptibility to ampicillin, carbenicillin, ticarcillin, and amoxicillin-clavulanic acid. No major difference in susceptibility was observed between any of the groups of human or animal strains included in the study, but nonsusceptibility to tetracycline increased from 0.4% in 1985 to 2% in 1990 in human strains isolated in those years. Our results indicate that between 1972 and 1990 there was no marked decrease in susceptibility to agents commonly used for therapy among pathogenic Y. enterocolitica strains isolated in Canada.Yersinia enterocolitica has emerged as a significant human pathogen associated with several clinical syndromes, including enterocolitis, mesenteric adenitis, focal extraintestinal infections, septicemia, and posttransfusion septic shock (3,5,17). Secondary immunological conditions, including erythema nodosum and reactive arthritis, are recognized complications of Y enterocolitica infection (5). Systemic and extraintestinal infections and enterocolitis in immune-compromised patients require prompt antibiotic therapy, and the agents used most commonly include chloramphenicol, gentamicin, tetracycline, cotrimoxazole, and, more recently, ciprofloxacin (3,7,14).Compared with other bacterial enteropathogens, relatively little is known about the antimicrobial susceptibilities of pathogenic Y enterocolitica isolated from humans in Canada. Y enterocolitica infection is essentially a zoonosis, and the serotypes that cause human infection are also isolated from domestic animals, including pigs, dogs, and cats; wild animals; and the environment (9). In 1990, Kwaga and Iversen (11) investigated the in vitro susceptibilities of yersiniae isolated from slaughtered ...

The incidence of Neisseria gonorrhoeae with reduced susceptibility to quinolones increased from 0.18% (63 of 3285) in 1992 to 0.56% (15 of 2663) in 1993 and 0.62% (46 of 2846) in 1994. In all, 65 of the 67 isolates of Neisseria gonorrhoeae with decreased susceptibility to quinolones were characterised by pulsed-field gel electrophoresis (PFGE), auxotyping, serotyping and plasmid content. The strains were distributed among 14 auxotype/serovar (A/S) classes. Thirty isolates (46.2%) which were penicillinsusceptible with ciprofloxacin MIC90 of 0.12 mg/L and norfloxacin MIC90 of 1.0 mg/L belonged to a single A/S class, OUHL/IA-2. All but two of the 30 isolates had identical PFGE restriction profiles with Nhe I restriction endonuclease. Fifteen isolates (23.1 YO) with MICs in the intermediate (or resistant) categories for penicillin and with ciprofloxacin and norfloxacin MIC90 of 0.25 and 4.0mg/L and (0.5 and 4.0 mg/L) respectively, belonged to A/S class P/IB-1. The 15 isolates showed nine different patterns with NheI and eight patterns with SpeI restriction endonucleases. Two of three P-lactamase-producing (PPNG) isolates belonged to A/S class P/IB-5 and had a dissimilar PFGE restriction profile with NheI endonuclease; the other isolate belonged to A/S class P/IB-8. The remaining 17 isolates were distributed among 11 A/S classes. Three isolates within the common A/S class NR/IB-1 were subdivided into two types by PFGE as were three isolates belonging to A/S class NR/IB-2. Overall the 65 isolates of N. gonorrhoeae were distributed into 30 NheI and 26 SpeI macrorestriction profiles. All but one isolate harboured the 2.6-MDa cryptic plasmid and 18 isolates carried the 24.5-MDa transferable plasmid. The three PPNG isolates carried the 4.5-MDa Asian plactamase-producing plasmid and a 25.2-MDa conjugative plasmid was found in the two TRNG isolates.

The Ontario Public Health Laboratories system (OPHL) is in the midst of a six-year plan to implement molecular tools for pandemic influenza diagnostics in one central and three regional public health laboratories. This plan has been formulated as a consequence of: 1) experiences gained through severe acute respiratory syndrome (SARS), and comments of the members of the Expert Panel on SARS and Infectious Disease Control (i.e., the Walker report); 2) a review of pandemic preparedness literature; 3) historical and epidemiologic discussions about previous pandemics; and 4) suggestions made by various pandemic working committees. The OPHL plan includes: 1) an aggressive restructuring of the overall molecular microbiology testing capacity of the OPHL; 2) the ability to shift influenza testing of samples between designated OPHL laboratories; and 3) the development of screening tools for pandemic influenza diagnostic tests. The authors believe that investing in increased molecular testing capacity for regional laboratories outside the greater Toronto area will be beneficial to the OPHL system whether or not an influenza pandemic occurs. Well-trained technologists and microbiologists, and the introduction of new technologies, will facilitate the development of a wide variety of molecular tests for other infectious diseases at public health laboratories geographically distant from Toronto, thus enhancing overall laboratory testing capacity in the province of Ontario.La traduction du résumé se trouve à la fin de l'article.

Streptococcal lymphadenitis with macroscopic abscesses was induced in guinea-pigs when an isolate of Lancefield's group C streptococci of guinea-pig origin was sprayed orally. The disease was also produced in guinea-pigs when another isolate was injected sublingually but not when it was sprayed orally. Treatment with prednisolone did not increase the susceptibility to the latter isolant when sprayed orally. Abscesses could not be induced in the cervical lymph nodes of guinea-pigs exposed by injecting group E streptococci sublingually, although the organism was isolated from the cervical lymph nodes 2 days after inoculation. Neither could abscesses be induced by injecting these streptococci sublingually in guinea-pigs treated with prednisolone.