Molecular Epidemiology of Multidrug-Resistant Klebsiella pneumoniae Isolates in a Brazilian Tertiary Hospital

Abstract

Multidrug-resistant (MDR) Klebsiella pneumoniae (Kp) is a major bacterial pathogen responsible for hospital outbreaks worldwide, mainly via the spread of high-risk clones and epidemic resistance plasmids. In this study, we evaluated the molecular epidemiology and β-lactam resistance mechanisms of MDR-Kp strains isolated in a Brazilian academic care hospital. We used whole-genome sequencing to study drug resistance mechanisms and their relationships with a K. pneumoniae carbapenemase-producing (KPC) Kp outbreak. Forty-three Kp strains were collected between 2003 and 2012. Antimicrobial susceptibility testing was performed for 15 antimicrobial agents, and polymerase chain reaction (PCR) was used to detect 32 resistance genes. Mutations in ompk35 , ompk36 , and ompk37 were evaluated by PCR and DNA sequencing. Pulsed field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) were carried out to differentiate the strains. Based on distinct epidemiological periods, six Kp strains were subjected to whole-genome sequencing. β-lactamase coding genes were widely distributed among isolates. Almost all isolates had mutations in porin genes, particularly ompk35 . The presence of bla KPC promoted a very high increase in carbapenem minimum inhibitory concentration only when ompk35 and ompk36 were interrupted by insertion sequences. A major cluster was identified by PFGE analysis and all isolates from this cluster belonged to clonal group (CG) 258. We have also identified a large repertoire of resistance genes in the sequenced isolates. A bla KPC–2 -bearing plasmid (pUFPRA2) was also identified, which was very similar to a plasmid previously described in the first Brazilian KPC-Kp (2005). We found high-risk clones (CG258) and an epidemic resistance plasmid throughout the duration of the study (2003 to 2012), emphasizing a persistent presence of MDR-Kp strains in the hospital setting. Finally, we found that horizontal transfer of resistance genes between clones may have played a key role in the evolution of the outbreak.

Characterization of Carbapenemase-Producing Klebsiella pneumoniae in Clinical Center University of Sarajevo, Bosnia and Herzegovina

“…This could result in outbreaks hard to control. 27 As shown in our results, MIC of imipenem varied between 2 and 8 mg/mL, which is not unusual because of intermediate susceptibility and even susceptibility to carbapenems observed in producers of all types of carbapenemases, 28 especially of OXA-48/OXA-181 isolates not coproducing an ESBL. 7 Although many carbapenem-resistant K. pneumoniae strains have been highly resistant, aminoglycosides can exhibit partial bactericidal activity against these isolates.…”

Synergistic antibacterial effects of colistin in combination with aminoglycoside, carbapenems, cephalosporins, fluoroquinolones, tetracyclines, fosfomycin, and piperacillin on multidrug resistant Klebsiella pneumoniae isolates

“…In addition, isolate 1TR5R was susceptible to tobramycin, ceftazidime, and minocycline. Multidrug resistant K. pneumoniae has been reported by previous researchers [32,33], and is globally spreading unabated. This might lead to increased hospital stay and K. pneumoniae associated mortality.…”

Epidemiology of β-Lactamase-Producing Pathogens

“…In addition to K. pneumoniae, KPC-type ␤-lactamases were also found in E. aerogenes, E. coli, K. oxytoca, C. freundii, and several other species (199). Outside the United States, recent outbreaks of KPCproducing K. pneumoniae have been reported in Brazil, China, Ecuador, Germany, Greece, South Korea, Poland, Portugal, Switzerland, and Taiwan (213,(218)(219)(220)(225)(226)(227)(228)(229)(230)(231)(232). A widely publicized outbreak of KPC-producing K. pneumoniae in the United States was documented in a clinical trial unit at the National Institutes of Health, resulting in the death of 11 of 18 infected patients as a result of infection-associated causes (233).…”