Non-clonal occurrence of pmrB mutations associated with polymyxin resistance in carbapenem-resistant Klebsiella pneumoniae in Brazil

Autor: Ana Claudia Souza Rodrigues, Ivson Cassiano de Oliveira Santos, Caroline Conci Campos, Isadora Nascimento Rezende, Yanara Miranda Ferreira, Claudia Elisabeth Volpe Chaves, Cláudio Marcos Rocha-de-Souza, Ana Paula D’Alincourt Carvalho-Assef, Marilene Rodrigues Chang
Jazyk: angličtina
Rok vydání: 2019
Předmět:
Zdroj: Memorias do Instituto Oswaldo Cruz, Vol 114, Iss 0 (2019)
Druh dokumentu: article
ISSN: 1678-8060
0074-0276
DOI: 10.1590/0074-02760180555
Popis: BACKGROUND Polymyxins are currently used as a “last-line” treatment for multidrug-resistant Gram-negative infections. OBJECTIVES To identify the major mechanisms of resistance to polymyxin and compare the genetic similarity between multi-drug resistant Klebsiella pneumoniae strains recovered from inpatients of public hospitals in the Mid-West of Brazil. METHODS 97 carbapenems non-susceptible K. pneumoniae were studied. β-lactamases (bla OXA-48, bla KPC, bla NDM, bla CTX-M, bla SHV, bla TEM, bla IMP, bla VIM) and mcr-1 to mcr-5 genes were investigated by polymerase chain reaction (PCR). Mutations in chromosomal genes (pmrA, pmrB, phoP, phoQ, and mgrB) were screened by PCR and DNA sequencing. Clonal relatedness was established by using pulsed-field gel electrophoresis and multilocus sequence typing. FINDINGS K. pneumoniae isolates harbored bla KPC (93.3%), bla SHV (86.6%), bla TEM (80.0%), bla CTX-M (60%) genes. Of 15 K. pneumoniae resistant to polymyxin B the authors identified deleterious mutations in pmrB gene, mainly in T157P. None K. pneumoniae presented mcr gene variants. Genetic polymorphism analyses revealed 12 different pulsotypes. MAIN CONCLUSIONS Deleterious mutations in pmrB gene is the main chromosomal target for induction of polymyxin resistance in carbapenem-resistant K. pneumoniae in public hospitals in the Mid-West of Brazil.
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