Molecular characterization, sensitivity profile and biofilm production from bulk tank milk Escherichia coli.

Author(s)

Samea Fernandes Joaquim

• Document type: Doctoral Thesis
• Press: Botucatu. 2020-03-04.
• Institution: Universidade Estadual Paulista (Unesp). Faculdade de Medicina Veterinária e Zootecnia. Botucatu
• Defense date: 2020-02-17
• Advisor: Helio Langoni

Abstract

Coliforms found in milk can be of animal origin in cases of mastitis or from faults in the hygienic production of milk. Molecular studies to identify Escherichia coli strains in expansion tanks are incipient. Thus, the aim of this study were identify E. coli isolates in dairy expansion tanks, genes associated with virulence factors and involved in biofilms formation and identify genes from isolates producers of extended spectrum β-lactamase (ESBL), as well as phenotypic studies of antimicrobial multiresistance and formation of biofilms in different materials. 149 E. coli samples were isolated, among which, 24.2% obtained a multiple antimicrobial resistance index (IRMA)> 0.3. As for the formation of biofilms, 42.28% of the isolates produced in polystyrene plastic, 21.48% in stainless steel and 56.38% in silicone. As for the susceptibility of biofilm producers to iodine and chlorhexidine digluconate, these disinfectants were able to inhibit the formation of biofilm, but their effect was reduced in 25.40% of the samples after the formation of the mature biofilm. Genes related to biofilm production were detected, however E. coli common pilus genes showed a negative association with phenotypic production in the analyzed materials (p<0.05). Extra-intestinal E. coli genes have been found for adhesins, toxins, siderophores and serum resistance. No genes were found that correlated with diarrhogenicE. coli virulence factors. Before the results obtained, it is hoped to deepen the knowledge of this pathogen, in order to enable control strategies to improve the quality of milk in expansion tanks, aiming at public health. (AU)

• FAPESP's process: 17/07246-6 - Molecular characterization, sensitivity profile and biofilm production from Escherichia coli isolated from bulk tanks
• Grantee: Samea Fernandes Joaquim
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)