Carbapenem Non-Susceptible Enterobacteriaceae in Quebec, Canada: Results of a Laboratory Surveillance Program (2010–2012)

April Carbapenem Non-Susceptible Enterobacteriaceae in Quebec, Canada: Results of a Laboratory Surveillance Program (2010-2012) Brigitte Lefebvre 0 1 Simon Lvesque 0 1 Anne-Marie Bourgault 0 1 Michael R. Mulvey 0 1 Laura Mataseje 0 1 David Boyd 0 1 Florence Doualla-Bell 0 1 Ccile Tremblay 0 1 0 1 Laboratoire de sante publique du Quebec, Institut national de sante publique du Quebec , Sainte-Anne-de- Bellevue, Quebec , Canada , 2 McGill University Health Centre and Department of Medicine, McGill University , Montreal, Quebec , Canada , 3 Bacteriology and Enteric Diseases Program, National Microbiology Laboratory, Public Health Agency of Canada , Winnipeg, Manitoba , Canada , 4 Centre de Recherche du Centre Hospitalier de l'Universite de Montreal , Montreal, Quebec , Canada 1 Academic Editor: Jose M. Sanchez-Ruiz, Universidad de Granada , SPAIN The emergence and spread of carbapenemase-producing Enterobacteriaceae (CPE) represent a major public health concern because these bacteria are usually extensively resistant to most antibiotics. In order to evaluate their dissemination in Quebec, a surveillance program was introduced in 2010. We report the molecular and epidemiological profiles of CPE isolates collected. Between August 2010 and December 2012, a total of 742 non-duplicate isolates non-susceptible to carbapenems were analysed. AmpC -lactamase and metallo--lactamase production were detected by Etest and carbapenemase production by the modified Hodge test (MHT). Antibiotic susceptibility profiles were determined using broth microdilution or Etest. Clonality of Klebsiella pneumoniae carbapenemase (KPC) strains was analyzed by pulsed-field gel electrophoresis (PFGE). The presence of genes encoding carbapenemases as well as other -lactamases was detected using PCR. Of the 742 isolates tested, 169 (22.8%) were CPE. Of these 169 isolates, 151 (89.3%) harboured a blaKPC gene while the remaining isolates carried blaSME (n = 9), blaOXA-48 (n = 5), blaNDM (n = 3), and blaNMC (n = 1) genes. Among the 93 KPC strains presenting with a unique pattern (unique PFGE pattern and/or unique antibiotics susceptibility profile), 99% were resistant to ertapenem, 95% to imipenem, 87% to meropenem, 97% to aztreonam, 31% to colistin and 2% to tigecycline. In 19 patients, 2 to 5 KPC strains from different species or with a different PFGE pattern were isolated. CPE strains were present in the province of Quebec with the majority of strains harbouring KPC. Alternately, SME, OXA-48 and NMC containing strains were rarely found. - Competing Interests: The authors have declared that no competing interests exist. Carbapenems (i.e. ertapenem, meropenem, imipenem, doripenem) are bactericidal antibiotics of the -lactam family. The emergence of carbapenemase-producing Enterobacteriaceae (CPE) is a major health concern because these bacteria are resistant to multiple classes of antibiotics that can lead to therapeutic failure [1]. Carbapenem resistance has been associated with different mechanisms including carbapenemase production, overexpression of chromosomal AmpC and porin mutations or ESBL production combined to porin mutations. Enterobacteriaceae harbouring carbapenemases belong to one of three classes according to the Ambler classification system [2]: class A serine -lactamases (i.e. Klebsiella pneumoniae carbapenemase [KPC], Serratia marcescens enzyme [SME], not metalloenzyme carbapenemase [NMC]), class B metallo--lactamase (i.e. New Delhi metallo-beta-lactamase [NDM]) and the class D oxacillinase (i.e. oxacillin-hydrolyzing [OXA-48]). Carbapenemase genes are known to have chromosomal or plasmid localization [2]. Bacterial transmission of carbapenemase genes is related to the transfer of mobile genetic elements such as plasmids or transposons [2] thereby facilitating outbreaks. The first strain of K. pneumoniae producing KPC carbapenemase was identified in North Carolina, United States of America from 1996 [3]. Several outbreaks associated with these strains have been documented in USA, South America, Europe, China [4] and in Canada [5]. Furthermore, these strains are endemic in several countries such as Israel, Colombia, Greece, Puerto Rico, and in the East Coast states of the United States [4]. Numerous outbreaks caused by strains other than KPC such as OXA-48 have been reported in Europe [6] and the Middle East [7,8]. The NDM carbapenemase was described in 2009 in Sweden [9] and subsequently identified in India [10], Pakistan [10], England [11], United States [12] and Canada [1316]. In light of the worldwide emergence of CPE, the Laboratoire de sant publique du Qubec (LSPQ) launched a provincial laboratory surveillance program in August 2010. In this study, we present the first molecular and epidemiological report of carbapenem non-susceptible Enterobacteriaceae (CNSE) recovered in the province of Quebec, from 2010 to 2012. From August 2010 to December 2012 (29 months), all clinical laboratories in the province of Quebec were asked to send their carbapenem non-susceptible Enterobacteriaceae (CNSE) isolates to the provincial reference laboratory of Quebec (LSPQ). Analysis of isolates in mandatory surveillance context is part of the mandate of the LSPQ. The isolates selection criteria followed the Clinical and Laboratory Standards Institute (CLSI) carbapenem breakpoints of 2011 [17]. The isolates had to meet at least one of the listed criteria: ertapenem MIC 0.5 mg/L ( 22 mm by disk diffusion) and/or imipenem MIC 2 mg/L ( 22 mm by disk diffusion) and/or meropenem MIC 2 mg/L ( 22 mm by disk diffusion). As Proteus spp., Providencia spp. and Morganella spp. may have elevated imipenem MICs by mechanisms other than carbapenemase production [17], inclusion criteria for these species were based only on ertapenem and meropenem susceptibility results. In July 2012, the inclusion criteria were modified to comply with the most recent CLSI recommendation [18] and inclusion breakpoints became ertapenem MIC 1 mg/L ( 21 mm by disk diffusion) and meropenem MIC 2 mg/L ( 22 mm by disk diffusion). For Klebsiella spp., the inclusion criterion was based on ertapenem MIC only ( 1 mg/L or 21 mm by disk diffusion). Antimicrobial susceptibility testing Antibiotic susceptibility was determined by the broth microdilution method following CLSI guidelines [18] for all antibiotics except aztreonam, cefoxitin and tigecycline. For these three antibiotics, MICs were determined using epsilometer test (Etest) following the manufacturer's recommendations (BioMrieux, St-Laurent, QC, Canada). The antibiotics tested were as follows: amikacin, aztreonam, cefepime, cefotaxime, cefoxitin, ceftazidime, ciprofloxacin, colistin, ertapenem, gentamicin, imipenem, meropenem, piperacillin, piperacillin-tazobactam, tigecycline and tobramycin. When available, the MIC results were interpreted according to CLSI criteria. For colistin, the European Committee for Antimicrobial Susceptibility Testing (EUCAST) criteria (http://www.eucast.org/ (...truncated)