Resumo

Carbapenem resistance in Klebsiella pneumoniae mediated by KPC production is becoming a significant clinical problem. Recently, other members of the Enterobacteriaceae family have also been shown to harbor the bla_KPC genes. These genes are encoded on mobile genetic elements, often plasmid and transposons, which probably explains the rapid spread of these determinants of resistance. We reported here the presence of KPC-producing K. pneumoniae and Escherichia coli isolates, obtained from urine and rectal swab samples from one patient, attended at a public hospital in Recife, Brazil. Isolates were identified by biochemical standard methods. MICs values were determined by broth microdilution, according to CLSI (2010). Isolates were tested for the presence of bla_KPC, bla_NMC-A, bla_IMI, bla_CTX-M, bla_SHV, bla_TEM, bla_IMP, bla_SPM, bla_OXA groups and Intl1 (class 1 integrase gene) by specific PCR, as previously reported. E. coli J53 recipient strain was used for conjugation assays. Transconjugants were selected on Müeller Hinton agar containing 100µg/mL azide and 50µg/mL ticarcilin. The plasmids extracted from the resulting colonies were screened by PCR for detection of bla_KPC. MIC results showed that K. pneumoniae was resistant to all the antimicrobials tested. By contrast, the E. coli isolate showed susceptibility to imipenem and meropenem . Both isolates were susceptible to polymyxin B (MIC ≤0,25 µg/mL). Molecular analysis revealed the presence of bla_KPC, bla_CTX-M, bla_SHV and Intl1 genes in both K. pneumoniae and E. coli isolates. None isolate presented class B or D carbapenemases. Results showed that conjugative plasmids were present in both species. However, there was not a common plasmid between the isolates. Our findings indicated that, despite their presence in the same patient, the bacterial isolates acquired KPC genes from distinct plasmids, suggesting these events were probably resulted from selective pressure in the environment. Moreover, the results showed that plasmid-mediated-KPC may easily spread among several bacterial isolates, alerting us to increase the efforts for containment the spread of such strains.