Antimicrobial activity evaluation and comparison of methods of susceptibility for Klebsiella pneumoniae carbapenemase (KPC)-producing Enterobacter spp. isolates

Abstract The production of KPC (Klebsiella pneumoniae carbapenemase) is the major mechanism of resistance to carbapenem agents in enterobacterias. In this context, forty KPC-producing Enterobacter spp. clinical isolates were studied. It was evaluated the activity of antimicrobial agents: polymyxin B, tigecycline, ertapenem, imipenem and meropenem, and was performed a comparison of the methodologies used to determine the susceptibility: broth microdilution, Etest® (bioMérieux), Vitek 2® automated system (bioMérieux) and disc diffusion. It was calculated the minimum inhibitory concentration (MIC) for each antimicrobial and polymyxin B showed the lowest concentrations for broth microdilution. Errors also were calculated among the techniques, tigecycline and ertapenem were the antibiotics with the largest and the lower number of discrepancies, respectively. Moreover, Vitek 2® automated system was the method most similar compared to the broth microdilution. Therefore, is important to evaluate the performance of new methods in comparison to the reference method, broth microdilution.

Qualidade microbiológica da água do Lago Igapó de Londrina - PR e caracterização genotípica de fatores de virulência associados a Escherichiacoli enteropatogênica (EPEC) e E. coli produtora de toxina Shiga (STEC) / Microbiological water quality of Igapó Lake Londrina - PR and genotypic characterization of virulence factors associated with enteropathogenic Escherichia coli (EPEC) and Shiga toxin-producing E. coli (STEC)

Esse trabalho teve como objetivo a detecção e quantificação de coliformes totais e Escherichia coli, no Lago Igapó, com a finalidade de avaliar a qualidade destas águas como próprias ou impróprias para recreação, além da caracterização genotípica de fatores de virulência associados a EPEC e STEC pela técnica da PCR. A área de estudo foi o Lago Igapó I, II, III e IV. As coletas foram realizadas mensalmente entre março de 2011 a fevereiro de 2012. A técnica utilizada para detecção e quantificação de Coliformes Totais e E. coli foi a do substrato cromogênico Colilert. Na PCR os genes eae e bfp foram pesquisados para caracterizar o patotipo de EPEC típica; stx1, stx2, eae e hlyA o de STEC e as que apresentaram somente o gene eae foram caracterizadas como EPEC atípica. De acordo com a Resolução CONAMA 357/2005, foi observado que para a recreação de contato primário, apenas o Lago Igapó III foi classificado impróprio, já para recreação de contato secundário, todos os lagos apresentaram-se próprios. Além disso, pode ser observada uma forte relação entre o índice pluviométrico e os índices deE. coli no Lago Igapó, na qual em meses mais secos a sua quantidade decresce drasticamente, enquanto que em meses chuvosos se observava uma relação contrária. Das 97 cepas de E. coli isoladas, duas apresentaram o gene eae (EPEC atípica). Nenhum isolado apresentou os genes stx1, stx2, bfp e hlyA. Desse modo, esperamos conscientizar a população e os órgãos públicos da importância do monitoramento microbiológico das águas recreacionais para prevenção de surtos de infecções de veiculação hídrica.

This work aimed at the detection and quantification of total coliforms and Escherichia coli in IgapóLake, in order to evaluate the quality of these waters as proper or unfit for recreation, in addition to the genotypic characterization of virulence factors associated with EPEC and STEC by PCR. The study areawas the Igapó Lake I, II, III and IV. Samples were collected monthly from March 2011 to February 2012.The technique used for the detection and quantification of Total Coliforms and E. coli was the Colilert chromogenic substrate. In the technique of PCR, the eae and bfp genes were tested to characterize the typical EPEC pathotype; stx1, stx2, eae and hlyA the STEC pathotype and the samples that presented only the eae gene were characterized as atypical EPEC. According to CONAMA Resolution 357/2005, it has been observed that only Igapó Lake III was rated inappropriate for primary contact recreation, while for secondary contact recreation, all lakes were considered appropriate. Moreover, a strong relationship between rainfall and E. coli indices in Igapó Lake can be observed, which in dry months the quantity drastically decreases, while in rainy months the opposite relationship was observed. Of the 97 strains of E. coli isolated, two had the eae gene (atypical EPEC). None of the isolates contained genes stx1,stx2, bfp and hlyA. Thus, we hope to educate the population and public agencies of the importance of microbiological monitoring of recreational waters to prevent outbreaks of waterborne infections.