OBJECTIVES: We aimed to characterise the staphylococcal cassette chromosome mec (SCCmec) type, genetic relatedness, biofilm formation and composition, icaADBC genes detection, icaD expression, and antibiotic susceptibility of planktonic and biofilm cells of @entity794 hominis isolates from blood. METHODS: The study included 67 @entity5940 blood isolates. @entity3256 resistance was evaluated with the cefoxitin disk test. mecA gene and SCCmec were detected by multiplex PCR. Genetic relatedness was determined by pulsed-field gel electrophoresis. Biofilm formation and composition were evaluated by staining with crystal violet and by detachment assay, respectively; and the biofilm index (BI) was determined. Detection and expression of icaADBC genes were performed by multiplex PCR and real-time PCR, respectively. Antibiotic susceptibilities of planktonic cells (minimum inhibitory concentration, MIC) and biofilm cells (minimum biofilm eradication concentration, MBEC) were determined by the broth dilution method. RESULTS: Eighty-five percent (57/67) of isolates were @entity3256 resistant and mecA positive. Of the mecA-positive isolates, 66.7% (38/57) carried a new putative SCCmec type. Four clones were detected, with two to five isolates each. Among all isolates, 91% (61/67) were categorised as strong biofilm producers. Biofilm biomass composition was heterogeneous (polysaccharides, proteins and DNA). All isolates presented the icaD gene, and 6.66% (1/15) isolates expressed icaD. This isolate presented the five genes of ica operon. Higher BI and MBEC values than the MIC values were observed for @entity4509 , @entity2176 , @entity5136 , @entity6101 , @entity2177 , and @entity2755 . CONCLUSIONS: @entity5940 isolates were highly resistant to @entity3256 and other antimicrobials. Most of the detected SCCmec types were different than those described for @entity794 . Isolates indicated low clonality. The results indicate that @entity5940 is a strong biofilm producer with an extracellular matrix with similar composition of proteins, DNA and @entity3954 ; and presents high frequency and low expression of icaD gene. Biofilm production is associated with increased antibiotic resistance.

Antibiotic Susceptibility of Biofilm Cells and Molecular Characterisation of XXXX hominis Isolates from Blood.

@entity3256 :: ('MESH:D008712', 'Chemical') :: ['Methicillin', 'methicillin'] @entity2176 :: ('MESH:D014640', 'Chemical') :: ['vancomycin'] @entity3954 :: ('CHEBI:28009', 'Chemical') :: ['N-acetylglucosamine'] @entity794 :: ('1280', 'Species') :: ['S. aureus', 'Staphylococcus'] @entity4509 :: ('MESH:D000583', 'Chemical') :: ['amikacin'] @entity2177 :: ('MESH:D002939', 'Chemical') :: ['ciprofloxacin'] @entity6101 :: ('MESH:D010068', 'Chemical') :: ['oxacillin'] @entity5136 :: ('MESH:C098010', 'Chemical') :: ['linezolid'] @entity2755 :: ('MESH:D002701', 'Chemical') :: ['chloramphenicol'] @entity5940 :: ('2098', 'Species') :: ['S. hominis']
@entity794 :: (1280,Species) :: ['Staphylococcus']
