title: Sub-Inhibitory Concentration of Piperacillin-Tazobactam May be Related to Virulence Properties of Filamentous Escherichia coli.
abstract: Sub-inhibitory concentrations of antibiotics are always generated as a consequence of antimicrobial therapy and the effects of such residual products in bacterial morphology are well documented, especially the filamentation generated by beta-lactams. The aim of this study was to investigate some morphological and pathological aspects (virulence factors) of Escherichia coli cultivated under half-minimum inhibitory concentration (1.0 µg/mL) of piperacillin-tazobactam (PTZ sub-MIC). PTZ sub-MIC promoted noticeable changes in the bacterial cells which reach the peak of morphological alterations (filamentation) and complexity at 16 h of antimicrobial exposure. Thereafter the filamentous cells and a control one, not treated with PTZ, were comparatively tested for growth curve; biochemical profile; oxidative stress tolerance; biofilm production and cell hydrophobicity; motility and pathogenicity in vivo. PTZ sub-MIC attenuated the E. coli growth rate, but without changes in carbohydrate fermentation or in traditional biochemical tests. Overall, the treatment of E. coli with sub-MIC of PTZ generated filamentous forms which were accompanied by the inhibition of virulence factors such as the oxidative stress response, biofilm formation, cell surface hydrophobicity, and motility. These results are consistent with the reduced pathogenicity observed for the filamentous E. coli in the murine model of intra-abdominal infection. In other words, the treatment of E. coli with sub-MIC of PTZ suggests a decrease in their virulence.
authors.affiliation: Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627 - Pampulha, C.P. 486, Belo Horizonte, MG, CEP 31270-901, Brazil.
authors.forename: João Paulo Lopes
authors.initials: JP
authors.lastname: de Andrade
authors.affiliation: Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627 - Pampulha, C.P. 486, Belo Horizonte, MG, CEP 31270-901, Brazil.
authors.forename: Luiz
authors.initials: L
authors.lastname: de Macêdo Farias
authors.affiliation: Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627 - Pampulha, C.P. 486, Belo Horizonte, MG, CEP 31270-901, Brazil.
authors.forename: João Fernando Gonçalves
authors.initials: JF
authors.lastname: Ferreira
authors.affiliation: Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627 - Pampulha, C.P. 486, Belo Horizonte, MG, CEP 31270-901, Brazil.|Centro de Ciências Biológicas/MIP, Universidade Federal de Santa Catarina, Campus Universitário do Córrego Grande, sn, sala05, Bl. A, MIP, C.P. 476, Florianópolis, SC, CEP: 88040-970, Brazil.
authors.forename: Oscar
authors.initials: O
authors.lastname: Bruna-Romero
authors.affiliation: Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627 - Pampulha, C.P. 486, Belo Horizonte, MG, CEP 31270-901, Brazil.
authors.forename: Daniele
authors.initials: D
authors.lastname: da Glória de Souza
authors.affiliation: Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627 - Pampulha, C.P. 486, Belo Horizonte, MG, CEP 31270-901, Brazil.
authors.forename: Maria Auxiliadora Roque
authors.initials: MA
authors.lastname: de Carvalho
authors.affiliation: Departamento de Patologia, Centro de Ciências da Saúde, Universidade Federal do Espírito Santo, Av. Marechal Campos 1468, Bairro Maruípe, Vitória, ES, CEP: 29043-900, Brazil. keniavaleria@gmail.com.
authors.forename: Kênia Valéria
authors.initials: KV
authors.lastname: dos Santos
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000378:metabolism*; D018441:Biofilms / Q000187:drug effects / Q000254:growth & development; D004195:Disease Models, Animal; D004926:Escherichia coli / Q000166:cytology* / Q000187:drug effects* / Q000472:pathogenicity / Q000502:physiology; D004927:Escherichia coli Infections / Q000382:microbiology / Q000473:pathology; D059413:Intraabdominal Infections / Q000382:microbiology / Q000473:pathology; D008124:Locomotion / Q000187:drug effects; D008660:Metabolism / Q000187:drug effects; D051379:Mice; D008826:Microbial Sensitivity Tests; D010397:Penicillanic Acid / Q000031:analogs & derivatives* / Q000378:metabolism; D010878:Piperacillin / Q000378:metabolism; D000077725:Piperacillin, Tazobactam Drug Combination; D014774:Virulence / Q000187:drug effects
chemical_list: D000900:Anti-Bacterial Agents; D000077725:Piperacillin, Tazobactam Drug Combination; D010397:Penicillanic Acid; D010878:Piperacillin