Bacteremia due to Pasteurella dagmatis acquired from a dog bite, with a review of systemic infections and challenges in laboratory identification.

A case of bacteremia in a 74-year-old man, which was caused by Pasteurella dagmatis and complicated by thrombocytopenia, is presented. Microorganism identification was performed by the provincial reference laboratory using traditional biochemical profiling, completmented with both the sequencing of the 16S ribosomal RNA gene and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry; antibiotic-susceptibility testing was also performed. After treatment with the appropriate antibiotics, the patient fully recovered. Systemic infections attributed to this organism are rarely reported in the literature. Other reported cases of bacteremia due to P dagmatis are reviewed and compared with the present case. The challenges of relying on standard automatic identification are discussed, with alternative methodologies provided.

Les auteurs présentent un cas de bactériémie chez un homme de 74 ans, causé par un Pasteurella dagmatis et compliqué par une thrombocytopénie. Le laboratoire de référence provincial a identifié le microorganisme au moyen du profilage biochimique classique et l'a complété par le séquençage du gène de l'ARN ribosomique 16S et par la spectrométrie de masse à temps de vol par désorption-ionisation laser assistée par matrice. Le laboratoire a également effectué un test de susceptibilité aux antibiotiques. Après un traitement antibiotique pertinent, le patient s'est complètement rétabli. Les publications scientifiques contiennent peu de déclarations d'infections systémiques attribuées à cet organisme. D'autres cas de bactériémie à P dagmatis sont analysés et comparés à la présente situation. Les problèmes liés à l'identification automatique standard sont exposés et d'autres méthodologies sont proposées.

Antimicrobial susceptibility of clinical isolates of anaerobic bacteria in Ontario, 2010-2011.

The local epidemiology of antimicrobial susceptibility patterns in anaerobic bacteria is important in guiding the empiric treatment of infections. However, susceptibility data are very limited on anaerobic organisms, particularly among non-Bacteroides organisms. To determine susceptibility profiles of clinically-significant anaerobic bacteria in Ontario Canada, anaerobic isolates from sterile sites submitted to Public Health Ontario Laboratory (PHOL) for identification and susceptibility testing were included in this study. Using the E-test method, isolates were tested for various antimicrobials including, penicillin, cefoxitin, clindamycin, meropenem, piperacillin-tazobactam and metronidazole. The MIC results were interpreted based on guidelines published by Clinical and Laboratory Standards Institute. Of 2527 anaerobic isolates submitted to PHOL, 1412 were either from sterile sites or bronchial lavage, and underwent susceptibility testing. Among Bacteroides fragilis, 98.2%, 24.7%, 1.6%, and 1.2% were resistant to penicillin, clindamycin, piperacillin-tazobactam, and metronidazole, respectively. Clostridium perfringens was universally susceptible to penicillin, piperacillin-tazobactam, and meropenem, whereas 14.2% of other Clostridium spp. were resistant to penicillin. Among Gram-positive anaerobes, Actinomyces spp., Parvimonas micra and Propionibacterium spp. were universally susceptible to ß-lactams. Eggerthella spp., Collinsella spp., and Eubacterium spp. showed variable resistance to penicillin. Among Gram-negative anaerobes, Fusobacterium spp., Prevotella spp., and Veillonella spp. showed high resistance to penicillin but were universally susceptible to meropenem and piperacillin-tazobactam. The detection of metronidazole resistant B. fragilis is concerning as occurrence of these isolates is extremely rare. These data highlight the importance of ongoing surveillance to provide clinically relevant information to clinicians for empiric management of infections caused by anaerobic organisms.

Antimicrobial susceptibilities of clinical isolates of HACEK organisms.

The "HACEK" organisms are a group of fastidious Gram-negative bacteria that cause a variety of infections, including infective endocarditis. Antimicrobial susceptibility testing is not universally available, and therapy for these infections is often empirical. We report the antimicrobial susceptibilities of 70 clinical HACEK isolates to 18 antimicrobials. All isolates were susceptible to ceftriaxone and levofloxacin, indicating that these agents remain appropriate empirical choices for the treatment of infections with this group of organisms.

Bordetella holmesii, an emerging cause of septic arthritis.

Bordetella holmesii is a well-described pathogen in asplenic and immunocompromised patients. Here we report the first two published cases of septic arthritis caused by B. holmesii documented in apparently immunocompetent patients and unaccompanied by bacteremia.

Genetic and antigenic characterization of invasive endemic serogroup B Neisseria meningitidis from Ontario, Canada, in 2001-2010.

This study examined the antigenic and genetic diversity of serogroup B Neisseria meningitidis (MenB) recovered from invasive meningococcal disease (IMD) cases in Ontario, Canada, over the period 2001-2010 during which no MenB outbreaks had occurred. MenB was found to be responsible for 39 % of all IMD cases, with the remaining cases caused mainly by serogroups Y (28 %), C (23.5 %) and W135 (8 %). One hundred and ninety-three individual MenB case isolates were collected and characterized. Of the 88 sequence types (STs) identified, 75 were grouped into 14 known clonal complexes (CCs), whilst 13 STs were not assigned to any known CC. Fifty-seven different PorA genotypes and 88 STs defined the diversity of invasive MenB in Ontario, which supported the endemic nature of MenB disease in Ontario. Despite the presence of the hypervirulent ST-41/44 and ST-32 CCs, no single ST was predominant and responsible for a large number of IMD cases. Although the Québec outbreak clone of ST-269 was also found in Ontario, the 20 case isolates were genetically diverse: they grouped into seven STs and did not have a predominant PorA genotype. eburst analysis identified a new CC responsible for 14.5 % of the MenB case isolates. The six most common PorA variable region 2 (VR2) genotypes (VR2-9, -4, -14, -16, -13-1 and -16-3) were found in 67 % of invasive MenB isolates.

Epidemiology of serogroup B invasive meningococcal disease in Ontario, Canada, 2000 to 2010.

BACKGROUND: Invasive meningococcal disease (IMD) caused by serogroup B is the last major serogroup in Canada to become vaccine-preventable. The anticipated availability of vaccines targeting this serogroup prompted an assessment of the epidemiology of serogroup B disease in Ontario, Canada. METHODS: We retrieved information on confirmed IMD cases reported to Ontario's reportable disease database between January 1, 2000 and December 31, 2010 and probabilistically-linked these cases to Public Health Ontario Laboratory records. Rates were calculated with denominator data obtained from Statistics Canada. We calculated a crude number needed to vaccinate using the inverse of the infant (<1 year) age-specific incidence multiplied by expected vaccine efficacies between 70% and 80%, and assuming only direct protection (no herd effects). RESULTS: A total of 259 serogroup B IMD cases were identified in Ontario over the 11-year period. Serogroup B was the most common cause of IMD. Incidence ranged from 0.11 to 0.27/100,000/year, and fluctuated over time. Cases ranged in age from 13 days to 101 years; 21.4% occurred in infants, of which 72.7% were <6 months. Infants had the highest incidence (3.70/100,000). Case-fatality ratio was 10.7% overall. If we assume that all infant cases would be preventable by vaccination, we would need to vaccinate between 33,784 and 38,610 infants to prevent one case of disease. CONCLUSIONS: Although rare, the proportion of IMD caused by serogroup B has increased and currently causes most IMD in Ontario, with infants having the highest risk of disease. Although serogroup B meningococcal vaccines are highly anticipated, our findings suggest that decisions regarding publicly funding serogroup B meningococcal vaccines will be difficult and may not be based on disease burden alone.

Genetic and antigenic analysis of invasive serogroup C Neisseria meningitidis in Canada: A decrease in the electrophoretic type (ET)-15 clonal type and an increase in the proportion of isolates belonging to the ET-37 (but not ET-15) clonal type during the period from 2002 to 2009.

BACKGROUND: Serogroup C meningococcal disease has been endemic in Canada since the early 1990s, with periods of hyperendemic disease documented in the past two decades. The present study characterized invasive serogroup C meningococci in Canada during the period from 2002 to 2009. METHODS: Serogroup C meningococci were serotyped using monoclonal antibodies. Their clonal types were identified by either multilocus enzyme electrophoresis or multilocus sequence typing. RESULTS: The number of invasive serogroup C Neisseria meningitidis isolates received at the National Microbiology Laboratory (Winnipeg, Manitoba) for characterization has dropped from a high of 173 isolates in 2001 to just 17 in 2009, possibly related to the introduction of the serogroup C meningococcal conjugate vaccine. Before 2006, 80% to 95% of all invasive serogroup C meningococci belonged to the electrophoreic type (ET)-15 clonal type, and the ET-37 (but not ET-15) type only accounted for up to 5% of all isolates. However, beginning in 2006, the percentage of the ET-15 clonal type decreased while the ET-37 (but not ET-15) type increased from 27% in 2006 to 52% in 2009. The percentage of invasive serogroup C isolates not belonging to either ET-15 or ET-37 also increased. Most ET-15 isolates expressed the antigenic formula of C:2a:P1.7,1 or C:2a:P1.5. In contrast, the ET-37 (but not ET-15) isolates mostly expressed the antigens of C:2a:P1.5,2 or C:2a:P1.2. CONCLUSION: A shift in the antigenic and clonal type of invasive serogroup C meningococi was noted. This finding suggests vigilance in the surveillance of meningoccocal disease is warranted.

HISTORIQUE: La maladie à méningocoque du sérogroupe C est endémique au Canada depuis le début des années 1990, des périodes de maladie hyperendémique étant attestées depuis vingt ans. La présente étude caractérise des groupes de méningocoques invasifs du sérogroupe C au Canada entre 2002 et 2009. MÉTHODOLOGIE: Les chercheurs ont sérotypé les méningocoques du sérogroupe C au moyen d'anticorps monoclonaux. Ils ont déterminé leur groupe clonal par électrophorèse d'enzyme multilocus ou par typage séquentiel multilocus. RÉSULTATS: Le nombre d'isolats de Neisseria meningitidis invasifs du sérogroupe C envoyés au National Microbiology Laboratory de Winnipeg, au Manitoba, en vue de leur caractérisation a fléchi d'un pic de 173 isolats en 2001 à seulement 17 en 2009, peut-être en raison de l'adoption du vaccin conjugué contre le méningocoque du sérogroupe C. Avant 2006, de 80 % à 95 % de tous les méningocoques invasifs du sérogroupe C appartenaient au groupe clonal du type électrophorétique ET-15, et l'ET-37 (mais pas l'ET-15) ne représentait que jusqu'à 5 % de tous les isolats. Cependant, à compter de 2006, le pourcentage de groupe clonal ET-15 a diminué, tandis que l'ET-37 (mais pas l'ET-15) est passé de 27 % en 2006 à 52 % en 2009. Le pourcentage d'isolats invasifs du sérogroupe C n'appartenant ni à l'ET-15 ni à l'ET-37 a également augmenté. La plupart des isolats d'ET-15 exprimaient la formule antigénique C:2a:P1.7,1 ou C:2a:P1.5. Par contre, les isolats d'ET-37 (mais pas d'ET-15) exprimaient surtout les antigènes C:2a:P1.5,2 ou C:2a:P1.2. CONCLUSION: Les chercheurs ont remarqué une transition du groupe antigénique et clonal des méningocoques invasifs du sérogroupe C. En raison de cette observation, il serait judicieux d'être vigilant en matière de surveillance de la maladie à méningocoque.

Evaluation of CLSI agar dilution method and Trek Sensititre broth microdilution panel for determining antimicrobial susceptibility of Streptococcus pneumoniae.

Both the CLSI agar dilution method and Trek Sensititre broth microdilution panel for Streptococcus pneumoniae antimicrobial susceptibility testing were evaluated against the reference CLSI broth microdilution method using the most recently published CLSI breakpoints. While agar dilution was not an optimal method, the commercial panel appeared to be an acceptable method, with minor errors encountered for ceftriaxone, penicillin, and meropenem.

Epidemiology of invasive meningococcal disease with decreased susceptibility to penicillin in Ontario, Canada, 2000 to 2006.

Neisseria meningitidis has been relatively slow to acquire resistance to penicillin. We previously reported an increase in the incidence of invasive meningococcal disease (IMD) strains with decreased susceptibility to penicillin (DSP) in Ontario. Our objectives were to evaluate trends in IMD with DSP, to identify case-level predictors of IMD with DSP, and to evaluate the relationship among DSP, bacterial phenotype, and the likelihood of a fatal outcome. All IMD isolates received in Ontario between 2000 and 2006 were submitted to the Public Health Laboratories, Toronto, for confirmation of the species, serogroup determination, and susceptibility testing. Isolates were considered to be IMD strains with DSP if the penicillin MIC was > or =0.125 microg/ml. Temporal trends were evaluated using multivariable Poisson regression models. Correlates of diminished susceptibility and fatal outcome were evaluated with multivariable logistic regression models. The overall rate of IMD caused by strains with DSP in Ontario was approximately 1.20 cases per million population annually (95% confidence interval [95% CI], 0.99 to 1.46). Seventy-nine strains (21.7%) were IMD strains with DSP. There was no year-to-year trend in the incidence of IMD with DSP. IMD with DSP was strongly associated with strains of serogroups Y (odds ratio [OR], 6.3; 95% CI, 3.6 to 11.1) and W-135 (OR, 8.2; 95% CI, 4.0 to 16.7). Infection with serogroup B or C strains was associated with a marked increase in the risk of mortality (OR, 3.07; 95% CI, 1.39 to 6.75); however, no association between IMD with DSP and mortality was observed. In contrast to trends of the 1990s, the incidence of IMD with DSP was stable in Ontario between 2000 and 2006. In Ontario, the serogroup rather than the penicillin MIC is the microbiological parameter most predictive of mortality.

Rapid identification of herd effects with the introduction of serogroup C meningococcal conjugate vaccine in Ontario, Canada, 2000-2006.

In 2001, Canada's National Advisory Committee on Immunization endorsed a meningococcal serogroup C conjugate vaccine, which appears to provide durable serogroup-specific immunity while reducing nasopharyngeal carriage. With reference to direct and indirect effects on case occurrence, we sought to evaluate recent trends in the incidence of invasive meningococcal disease (IMD) in Ontario. Analyses included all IMD cases reported between 2000 and 2006 to the Ontario Central Public Health Laboratory. Poisson models incorporating terms for age, sex and seasonal oscillation identified a significant downward trend in disease occurrence, which was strongest in serogroup C cases and not evident when serogroup C strains were excluded from the analysis. Among age groups not targeted by the vaccine program serogroup C, IMD displayed a pattern of decreasing incidence that was not present in non-serogroup C disease. These apparent dramatic effects of conjugate C vaccine (both direct and indirect) may be important in the implementation and evaluation of vaccine policy in other jurisdictions.

Prevalence of and risk factors for quinolone-resistant Neisseria gonorrhoeae infection in Ontario.

BACKGROUND: Quinolone-resistant Neisseria gonorrhoeae has swiftly emerged in Canada. We sought to determine its prevalence in the province of Ontario and to investigate risk factors for quinolone-resistant N. gonorrhoeae infection in a Canadian setting. METHODS: We used records from the Public Health Laboratory of the Ontario Agency for Health Protection and Promotion in Toronto, Ontario, and the National Microbiology Laboratory in Winnipeg, Manitoba, to generate epidemic curves for N. gonorrhoeae infection. We extracted limited demographic data from 2006 quinolone-resistant N. gonorrhoeae isolates and from a random sample of quinolone-susceptible isolates. We also extracted minimum inhibitory concentrations for commonly tested antibiotics. RESULTS: Between 2002 and 2006, the number of N. gonorrhoeae infections detected by culture decreased by 26% and the number of cases detected by nucleic acid amplification testing increased 6-fold. The proportion of N. gonorrhoeae isolates with resistance to quinolones increased from 4% to 28% over the same period. Analysis of 695 quinolone-resistant N. gonorrhoeae isolates and 688 quinolone-susceptible control isolates from 2006 showed a higher proportion of men (odds ratio [OR] 3.1, 95% confidence interval [CI] 2.3-4.1) and patients over 30 years of age (OR 3.1, 95% CI 2.4-3.8) in the quinolone-resistant group. The proportion of men who have sex with men appeared to be relatively similar in both groups (OR 1.4, 95% CI 1.1-1.8). Quinolone-resistant strains were more resistant to penicillin (p < 0.001), tetracycline (p < 0.001) and erythromycin (p < 0.001). All isolates were susceptible to cefixime, ceftriaxone, azithromycin and spectinomycin. INTERPRETATION: During 2006 in Ontario, 28% of N. gonorrhoeae isolates were resistant to quinolones. Infections in heterosexual men appear to have contributed significantly to the quinolone resistance rate. Medical practitioners should be aware of the widespread prevalence of quinolone-resistant N. gonorrhoeae and avoid quinolone use for empiric therapy.