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O29 Province-wide perspective of Clostridium difficile infection in British Columbia: a one month prevalence study
Friday, June 19, 2009
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likely to cause skin and soft tissue infection, and more susceptible to antimicrobial agents as compared to hospital-associated MRSA strains (CMRSA2).
O30 The use of a multi locus sequence typing scheme to characterize Canadian isolates of Corynebacterium diphtheriae
O29 Province-wide perspective of Clostridium difficile infection in British Columbia: a one month prevalence study
K. Bernard1 *, S. Schindle2 , T. Burdz1 , D. Wiebe1 , A. Reimer, C. Dowson3 , F. Bolt3 , A. Baldwin3 . 1 National Microbiology Laboratory, Winnipeg, Canada, 2 University of Manitoba, Winnipeg, Canada, 3 University of Warwick, Warwick, United Kingdom
L. Janz1 , P. Umlandt1 , T. Rahim1 *, S. Champagne2 , M. Mulvey3 , D. Boyd3 , L. Hoang1 . 1 British Columbia Centre for Disease Control, Vancouver, Canada, 2 BCAMM-C. difficile Study Group, Vancouver, Canada, 3 National Microbiology Laboratory, Winnipeg, Canada Objective: The tcdC gene of C. difficile negatively regulates the production of toxins A and B. Mutations within this gene may result in loss of the negative regulatory role, potentially leading to hyperproduction of toxins and increased virulence. This hypervirulent strain caused an epidemic of C. difficile-associated disease in Quebec in 2002 and has been seen in increasing numbers in the western provinces, including BC. The objective of this study was to produce a baseline of the molecular and phenotypic profile of strains from participating centres to complement future infection control surveillance programs for C. difficile infection in BC. Methods: Over a one month period in March 2008, all stool specimens positive for C. difficile testing were cultured at participating laboratories or forwarded to the reference laboratory (BCCDC) for culture. Methods were standardized across participating laboratories. C. difficile was identified by colony morphology, Gram-stain, aerotolerance and C. difficile latex agglutination kit. The presence of the tcdC gene deletion was determined for each isolate using fragment analysis PCR. A fingerprint pattern was generated using pulsed-field gel electrophoresis (PFGE) and assigned PFGE pattern numbers and NAP type using the Canadian C. difficile database. Results: The total number of specimens received over the month of March 2008 from all participating sites was 414. Of these, 368 were culture confirmed cases of C. difficile. The tcdC gene mutation was detected in 189 (51.4%) isolates and the remaining 179 (48.6%) were wildtype strains with no mutation. Of those detecting a mutation, 145 (76.7%) displayed a mutation at ( 18)( 1) in the tcdC gene, associated with NAP1 PFGE designation and the remaining 29 (15.3%) showed a mutation other than at the ( 18)( 1) region. 156 (42.4%) of the total cases matched the NAP1 PFGE designation. Less common were PFGE patterns with NAP2 designation (9.5%) and NAP4 designation (7.8%). Conclusions: The prevalence of the NAP1 strain of C. difficile in the province of BC was 42% for March 2008. Of the C. difficile isolates recovered, the majority contained mutation at ( 18)( 1), with 15.3% exhibiting mutations at other sites within PaLoc. This study provides a baseline for infection control and public health functions in BC.
Objective: Classic diphtheria, caused by toxigenic Corynebacterium diphtheriae or C. ulcerans occurs only rarely in countries like Canada with universal vaccination programmes. Annually, there are small numbers of ‘not-notifiable’ infections whether or not strains express diphtheria toxin [DT]. A Multi Locus Sequence Typing [MLST] method and scheme, created by the University of Warwick [UW] UK, was used here to study genetic diversity among Canadian C. diphtheriae strains. Methods: Reference or wild diphtherial isolates were reviewed for patient demographics and identified as C. diphtheriae/biotypes using phenotypic, genetic and chemotaxonomic approaches. Antimicrobial susceptibility testing was done using CLSI guidelines. DT testing was done using standard PCR [Frag A, entire gene], with expression confirmed using modified ELEK. MLST method was obtained from the UW. Seven genes [atpA, dnaE, dnaK, fusA, leuA, odhA, rpoB] were sequenced [~350 390 bps/gene], edited, and data was sent for comparison a database of 154 isolates (from 1957 to 2007 across Europe, USA, Caribbean, and countries formerly within the USSR) curated by UW, whereupon an existing or new sequence type [ST] would be assigned. Results: Sources: 7, blood cultures; 5, respiratory sites; remaining 71 strains were from wounds, ears, eyes or unknown. Among the >86 existing STs in the UW database, only 15 STs were found among Canadian isolates, and STs 75 to 82, 84 and 85 were created to accommodate Canadian isolates. Predominating were: ST 76 [n = 25; 18, BC; 6 SK; 1 AB], followed by ST 32 [n = 11] and ST 50 [n = 10]. ST 50 isolates derived only from either SK or MB, were all C. diphtheriae biotype mitis; 7/10 were tox gene positive but DT was not detected [‘non-toxigenic’] whereas for 3/10, PCR was positive and DT could be detected [‘toxigenic’]. ST 5 [n = 6, all BC], were maltose negative and had elevated MICs to fluoroquinolones. Interestingly, there was no overlap of STs with respect to biotype: gravis isolates included ST 8, 32, 63, 75, 80, 82, 84; mitis/belfanti: ST 5, 26, 50, 76, 77, 78, 79, 81, 85; intermedius ST 38. Conclusions: Circulating Canadian strains appeared to be relatively unique compared with those from other countries deposited in the UW database. The MLST method was reproducible and should serve to enhance surveillance capabilities both nationally and internationally. A combination of phenotypic and genetic information will assist with strain tracking of infections from outbreaks or which may circulate among special patient populations.
S11
likely to cause skin and soft tissue infection, and more susceptible to antimicrobial agents as compared to hospital-associated MRSA strains (CMRSA2).
O30 The use of a multi locus sequence typing scheme to characterize Canadian isolates of Corynebacterium diphtheriae
O29 Province-wide perspective of Clostridium difficile infection in British Columbia: a one month prevalence study
K. Bernard1 *, S. Schindle2 , T. Burdz1 , D. Wiebe1 , A. Reimer, C. Dowson3 , F. Bolt3 , A. Baldwin3 . 1 National Microbiology Laboratory, Winnipeg, Canada, 2 University of Manitoba, Winnipeg, Canada, 3 University of Warwick, Warwick, United Kingdom
L. Janz1 , P. Umlandt1 , T. Rahim1 *, S. Champagne2 , M. Mulvey3 , D. Boyd3 , L. Hoang1 . 1 British Columbia Centre for Disease Control, Vancouver, Canada, 2 BCAMM-C. difficile Study Group, Vancouver, Canada, 3 National Microbiology Laboratory, Winnipeg, Canada Objective: The tcdC gene of C. difficile negatively regulates the production of toxins A and B. Mutations within this gene may result in loss of the negative regulatory role, potentially leading to hyperproduction of toxins and increased virulence. This hypervirulent strain caused an epidemic of C. difficile-associated disease in Quebec in 2002 and has been seen in increasing numbers in the western provinces, including BC. The objective of this study was to produce a baseline of the molecular and phenotypic profile of strains from participating centres to complement future infection control surveillance programs for C. difficile infection in BC. Methods: Over a one month period in March 2008, all stool specimens positive for C. difficile testing were cultured at participating laboratories or forwarded to the reference laboratory (BCCDC) for culture. Methods were standardized across participating laboratories. C. difficile was identified by colony morphology, Gram-stain, aerotolerance and C. difficile latex agglutination kit. The presence of the tcdC gene deletion was determined for each isolate using fragment analysis PCR. A fingerprint pattern was generated using pulsed-field gel electrophoresis (PFGE) and assigned PFGE pattern numbers and NAP type using the Canadian C. difficile database. Results: The total number of specimens received over the month of March 2008 from all participating sites was 414. Of these, 368 were culture confirmed cases of C. difficile. The tcdC gene mutation was detected in 189 (51.4%) isolates and the remaining 179 (48.6%) were wildtype strains with no mutation. Of those detecting a mutation, 145 (76.7%) displayed a mutation at ( 18)( 1) in the tcdC gene, associated with NAP1 PFGE designation and the remaining 29 (15.3%) showed a mutation other than at the ( 18)( 1) region. 156 (42.4%) of the total cases matched the NAP1 PFGE designation. Less common were PFGE patterns with NAP2 designation (9.5%) and NAP4 designation (7.8%). Conclusions: The prevalence of the NAP1 strain of C. difficile in the province of BC was 42% for March 2008. Of the C. difficile isolates recovered, the majority contained mutation at ( 18)( 1), with 15.3% exhibiting mutations at other sites within PaLoc. This study provides a baseline for infection control and public health functions in BC.
Objective: Classic diphtheria, caused by toxigenic Corynebacterium diphtheriae or C. ulcerans occurs only rarely in countries like Canada with universal vaccination programmes. Annually, there are small numbers of ‘not-notifiable’ infections whether or not strains express diphtheria toxin [DT]. A Multi Locus Sequence Typing [MLST] method and scheme, created by the University of Warwick [UW] UK, was used here to study genetic diversity among Canadian C. diphtheriae strains. Methods: Reference or wild diphtherial isolates were reviewed for patient demographics and identified as C. diphtheriae/biotypes using phenotypic, genetic and chemotaxonomic approaches. Antimicrobial susceptibility testing was done using CLSI guidelines. DT testing was done using standard PCR [Frag A, entire gene], with expression confirmed using modified ELEK. MLST method was obtained from the UW. Seven genes [atpA, dnaE, dnaK, fusA, leuA, odhA, rpoB] were sequenced [~350 390 bps/gene], edited, and data was sent for comparison a database of 154 isolates (from 1957 to 2007 across Europe, USA, Caribbean, and countries formerly within the USSR) curated by UW, whereupon an existing or new sequence type [ST] would be assigned. Results: Sources: 7, blood cultures; 5, respiratory sites; remaining 71 strains were from wounds, ears, eyes or unknown. Among the >86 existing STs in the UW database, only 15 STs were found among Canadian isolates, and STs 75 to 82, 84 and 85 were created to accommodate Canadian isolates. Predominating were: ST 76 [n = 25; 18, BC; 6 SK; 1 AB], followed by ST 32 [n = 11] and ST 50 [n = 10]. ST 50 isolates derived only from either SK or MB, were all C. diphtheriae biotype mitis; 7/10 were tox gene positive but DT was not detected [‘non-toxigenic’] whereas for 3/10, PCR was positive and DT could be detected [‘toxigenic’]. ST 5 [n = 6, all BC], were maltose negative and had elevated MICs to fluoroquinolones. Interestingly, there was no overlap of STs with respect to biotype: gravis isolates included ST 8, 32, 63, 75, 80, 82, 84; mitis/belfanti: ST 5, 26, 50, 76, 77, 78, 79, 81, 85; intermedius ST 38. Conclusions: Circulating Canadian strains appeared to be relatively unique compared with those from other countries deposited in the UW database. The MLST method was reproducible and should serve to enhance surveillance capabilities both nationally and internationally. A combination of phenotypic and genetic information will assist with strain tracking of infections from outbreaks or which may circulate among special patient populations.