Phenotypic and molecular evaluation of biofilm formation in carbapenemase (KPC) isolates obtained from a hospital of Pelotas, RS, Brazil.

A significant cause of mortality in the intensive care unit (ICU) is multidrug-resistant (MDR) Gram-negative bacteria, such as carbapenemase (KPC). Biofilm production is a key factor in KPC colonization and persistence in the host, making the treatment difficult. The aim of this study was to evaluate the antibiotic resistance, molecular and phenotypic biofilm profiles of 12 KPC isolates associated with nosocomial infection in a hospital in Pelotas, Rio Grande do Sul, Brazil. Clinical isolates were obtained from different sources, identified and characterized by antibiotic resistance and carbapenemase synthesis following the Clinical and Laboratory Standards Institute (CLSI) guidelines. Polymerase chain reaction (PCR) was used to evaluate the presence of carbapenemase () and biofilm formation-associated genes (, , , , and ). Additionally, phenotypic evaluation of biofilm formation capacity was evaluated by Congo red agar (CRA) assay and the crystal violet staining method. The 12 isolates evaluated in this study presented the gene and were positive for synthesizing carbapenemases . In the carbapenem class, 83.3 % isolates were resistant and 16.7 % intermediately resistant to imipenem and meropenem. Molecular analyses found that the and genes were detected in 75 % of isolates, while and were detected in 42 % and were detected in 8.3 % (1). The CRA assay demonstrated that all isolates were slime producers and 91.7 % (11) of isolates were classified as strong and 8.3 % (1) as moderate biofilm producers by the crystal violet staining method. The optical density (OD) for strong biofilm formers ranged from 0.80±0.05 to 2.47±0.28 and was 0.55±0.12 for moderate biofilm formers. Our study revealed a high level of antibiotic resistance and biofilm formation in KPC isolates obtained from a hospital in Pelotas, RS, Brazil.