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Multidrug-resistant Klebsiella pneumoniae harboring extended spectrum β-lactamase encoding genes isolated from human septicemias

2021; Public Library of Science; Volume: 16; Issue: 5 Linguagem: Inglês

10.1371/journal.pone.0250525

1932-6203

Isabel Carvalho, Nadia Safia Chenouf, José Antônio Mainardi de Carvalho, Ana Paula Castro, Vanessa Silva, Rosa Capita, Carlos Alonso‐Calleja, Maria de Lurdes Enes Dapkevicius, Gilberto Igrejas, Cármen Torres, Patrícia Poeta,

Pharmaceutical and Antibiotic Environmental Impacts

Klebsiella pneumoniae is a major pathogen implicated in nosocomial infections. Extended-spectrum β-lactamase (ESBL)-producing K . pneumoniae isolates are a public health concern. We aim to characterize the type of β-lactamases and the associated resistance mechanisms in ESBL-producing K . pneumoniae isolates obtained from blood cultures in a Portuguese hospital, as well as to determine the circulating clones. Twenty-two cefotaxime/ceftazidime-resistant (CTX/CAZ R ) K . pneumoniae isolates were included in the study. Identification was performed by MALDI-TOF MS and the antimicrobial susceptibility testing by disk-diffusion. The screening test for ESBL-production was performed and ESBL-producer isolates were further characterized. The presence of different beta-lactamase genes ( bla CTX-M , bla SHV , bla TEM , bla KPC , bla NDM, bla VIM, bla OXA-48, bla CMY-2 , bla DHA-1, bla FOX, bla MOX, and bla ACC ) was analyzed by PCR/sequencing in ESBL-producer isolates, as well as the presence of other resistance genes ( aac(6’)-Ib-cr , tet A/B, dfrA , qnr A/B/S, sul 1/2/3) or integron-related genes ( int 1/2/3). Multilocus-sequence-typing (MLST) was performed for selected isolates. ESBL activity was detected in 12 of the 22 CTX/CAZ R K . pneumoniae isolates and 11 of them carried the bla CTX-M-15 gene (together with bla TEM ) , and the remaining isolate carried the bla SHV-106 gene. All the bla CTX-M-15 harboring isolates also contained a bla SHV gene ( bla SHV-1 , bla SHV-11 or bla SHV-27 variants). Both bla SHV-27 and bla SHV-106 genes correspond to ESBL-variants. Two of the CTX-M-15 producing isolates carried a carbapenemase gene ( bla KPC2/3 and bla OXA-48 ) and showed imipenem resistance. The majority of the ESBL-producing isolates carried the int 1 gene, as well as sulphonamide-resistance genes ( sul 2 and/or sul 3); the tetA gene was detected in all eight tetracycline-resistant isolates. Three different genetic lineages were found in selected isolates: ST348 (one CTX-M-15/TEM/SHV-27/KPC-2/3-producer isolate), ST11 (two CTX-M-15/TEM/SHV-1- and CTX-M-15-TEM-SHV-11-OXA-48-producer isolates) and ST15 (one SHV-106/TEM-producer isolate). ESBL enzymes of CTX-M-15 or SHV-type are detected among blood K . pneumoniae isolates, in some cases in association with carbapenemases of KPC or OXA-48 type.