Detection of blaoxa genes and identification of biofilm-producing capacity of Acinetobacter baumannii in a tertiary teaching hospital, Klaten, Indonesia.

INTRODUCTION: Acinetobacter baumannii (A. baumannii) is commonly found as an agent of nosocomial infections and demonstrates a high antibiotic resistance due to its carbapenemase production. The objectives of this study were to explore the antibiotic resistance pattern, the presence of OXAs genes and the biofilm-producing capacity of A. baumannii isolated from clinical specimens. METHODS: Antibiotics susceptibility testing, detection of OXAs genes and the biofilm-producing capacity were performed using the Kirby Bauer method, polymerase chain reaction (PCR) and adherence quantitative assays, respectively. RESULTS: A total of 80 A. baumannii isolates were mainly obtained from sputum and most of them were resistant to antibiotics. All A. baumannii carried blaOXA-51 gene, yet no blaOXA-24 and blaOXA-58 genes were detected. Fourteen (82.4%) of the 17 meropenem resistant isolates carried blaOXA-23 gene, but it was not found in meropenem sensitive isolates. In addition, sixty (75.0%) of 80 isolates were biofilm producers with 2 (2.5%), 16 (20.0%), and 42 (52.5%) isolates were identified as strong, moderate and weak biofilm producers, respectively. CONCLUSION: Most of A. baumannii isolates had a high level of antibiotic resistance and had a capacity to produce biofilm.

Antibiofilm activity of (1)-N-2-methoxybenzyl-1,10-phenanthrolinium bromide against Candida albicans.

The therapy for invasive candidiasis related to biofilms infection remains a difficult medical problem. To overcome this problem, efforts have been made to search for novel antibiofilm agents from various sources. This study investigated the in vitro antibiofilm activity of (1)-N-2-methoxybenzyl-1,10-phenanthrolinium bromide (FEN) against Candida albicans. The minimum biofilm inhibitory concentration (MBIC) and minimum biofilm reduction concentration (MBRC) were determined using the MTT (3-(4-5-dimethylthiazol-2-yl)2,5-dyphenyl tetrazolium bromide) reduction assay. Biofilms on surfaces were visualized using scanning electron microscopy (SEM). This new compound inhibited the growth of C. albicans biofilms by 80 % with an MBIC80 range from 0.5-2.0µg/mL. The ability of FEN to reduce 50 % of a preformed biofilm was demonstrated by defining a MBRC50 range from 6.25--12.5µg/mL. To reduce 80 % of a preformed biofilm required higher concentrations >200µg/mL. In addition, SEM images showed disruption of C. albicans biofilms matrix exposed to FEN. These results indicated that (1)-N-2-methoxybenzyl-1,10-phenanthrolinium bromide has the potential to be developed as a new antibiofilm agent against C. albicans.

RecA mediated spontaneous deletions of the icaADBC operon of clinical Staphylococcus epidermidis isolates: a new mechanism of phenotypic variations.

Phenotypic variation in biofilm formation is common in clinical isolates of S. epidermidis. In the current study, nearly 5% of all clinical isolates analysed showed phenotypic variation in biofilm forming ability and electrophoretic mobility (EM). This is the first report of S. epidermidis strains irreversibly switching from biofilm-positive to biofilm-negative phenotype by spontaneous deletion of icaADBC genes which represents a new, possibly common mechanism of phenotypic variation.