Report of a KPC-producing Pseudomonas aeruginosa isolate in Canada

Sir, Enterobacteriaceae producing a KPC enzyme have been recovered in Canada, but to date KPC enzymes have not been documented among Pseudomonas aeruginosa in this country. This report briefly describes a patient in Canada colonized with a KPC-producing P. aeruginosa isolate. An elderly man with a history of hospital treatment in India was referred to a university-affiliated outpatient infectious diseases clinic (Winnipeg, Manitoba, Canada) for assessment regarding recurrent urinary tract infections. The patient previously had placement of a suprapubic Foley catheter in India to manage urinary obstruction. He had been living in Canada for a year prior to presentation. At the time he was evaluated in the infectious diseases clinic, he complained of restlessness and blood clots in his catheter, but was otherwise asymptomatic. A urine sample obtained through the suprapubic catheter was sent to the hospital’s clinical microbiology laboratory for culture. No antimicrobial treatment was provided as the patient did not have clear symptoms or signs consistent with urinary tract infection. A P. aeruginosa isolate was recovered on culture at a concentration of >1 × 105 cfu/mL using chromogenic medium (BBLTM CHROMagarTM Orientation; Becton, Dickinson and Company, Sparks, MD, USA). The isolate was identified with MALDI-TOF MS (Bruker MALDI Biotyper System, RUO MBT Compass 4.1.70; Bruker Daltonics Ltd, East Milton, Ontario, Canada). Susceptibility testing was performed with a VitekTM 2 AST-N208 card (bioMérieux, St Laurent, Quebec, Canada), with MICs interpreted according to current CLSI breakpoints.1 The isolate demonstrated phenotypic resistance to ceftazidime, meropenem, piperacillin/tazobactam, amikacin, gentamicin, tobramycin and ciprofloxacin. Meropenem resistance was confirmed by broth microdilution following the method described by CLSI.2 On supplemental testing (broth microdilution), the isolate was resistant to ceftolozane/tazobactam, but remained susceptible to colistin. Carbapenemase production was demonstrated phenotypically using a commercial colorimetric assay (the Neo-Rapid CARB Screen kit; Rosco Diagnostica, Taastrup, Denmark). The isolate was forwarded on to a provincial public health reference laboratory (Cadham Provincial Laboratory, Winnipeg, Manitoba, Canada) for carbapenemase gene detection by WGS on the MiSeq platform (Illumina, San Diego, CA, USA). The P. aeruginosa genome was assembled using the Integrated Rapid Infectious Diseases Analysis pipeline (www.irida.ca/) and the contigs analysed for antimicrobial resistance alleles by ResFinder on the Center for Genomic Epidemiology website (https://cge.cbs.dtu.dk/services/). The isolate was found to harbour the KPC-2 gene. Sequencing data associated with this isolate have been deposited in NCBI. KPC enzymes are a group of Ambler molecular class A serine carbapenemases.3 The first KPC gene was reported in a K. pneumoniae isolate from North Carolina (USA) in 1996.3 To date, there have been 23 different KPC enzymes described in the literature (KPC-2–24).4 KPC enzymes have been most frequently reported among members of the family Enterobacteriaceae, but they have also been described in several non-Enterobacteriaceae species.3,5 The first report of a KPC-producing P. aeruginosa was from Columbia in 2006.6 KPC-producing P. aeruginosa isolates have subsequently been described in Argentina, Brazil, China, India, Iran, Mexico City, Germany, Trinidad and Tobago, and the USA.4,7–15 In Canada, carbapenemase production among P. aeruginosa remains uncommon. Sporadic reports have described recovery of P. aeruginosa isolates harbouring a VIM or IMP enzyme.16 More recently, McCracken et al.17 systematically evaluated 382 meropenem-resistant P. aeruginosa clinical isolates for carbapenemase production. The isolates were obtained from patients seeking care at hospitals across Canada between 2007 and 2016 as part of the CANWARD study. Only 13 isolates were found to contain a carbapenemase gene. The specific genes detected were GES-5, VIM-2, VIM-4, IMP-18 and IMP-7.17 None of the isolates was found to harbour a KPC enzyme. It is thought that the KPC-producing isolate in the patient described here was likely acquired during a hospital stay in India, prior to his arrival in Canada. In conclusion, to the best of our knowledge, we present the first case of a KPC-producing P. aeruginosa clinical isolate in Canada. The finding of a KPC enzyme in P. aeruginosa is concerning, as there are already limited antimicrobial options for treating infections caused by this pathogen. This case highlights the risk for global spread of antimicrobial-resistant bacteria related to patient movement between countries. Ongoing surveillance in Canada for carbapenemase-producing P. aeruginosa is required to ensure these isolates are not increasing in frequency. This study was supported by internal funding. None to declare.

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