Genotypic and phenotypic analysis of biofilm formation Staphylococcus epidermidis isolates from clinical specimens.

OBJECTIVES: Staphylococcus epidermidis is the primary causative agent of infections associated with indwelling biomaterials. Antibiotic susceptibility patterns, Biofilm formation capability, and screening of responsible genes in biofilm formation procedure in clinical isolates (icaA, icaB, icaC, icaD, sdrG, and atlE) were assigned as the main objectives in this study. The clinical samples were analyzed via standard biochemical assays for identifying different bacteria which were confirmed using the multiplex colony PCR method. Subsequently, biofilm-formation capability, antibiotic susceptibility testing, and the frequency of genes responsible for biofilm formation in the confirmed strains were checked. RESULTS: Out of 183 clinical specimens 54 S. epidermidis isolates were detected by targeting a housekeeping gene (sesc) taking advantage of the PCR procedure. All of the strains were Biofilm forming producers. The in vitro biofilm formation assays determined that 45 (83.33%), 5 (9.26%), 4 (7.41%) were strong, moderate, and weak biofilm former strains respectively. Among the isolated strains, the specific frequencies of the biofilm-forming genes were specified to be (98%) for sdrG, (84%) for atlE, (80%) for icaC, and (70%) for icaD. Cefamandole and Amikacin are the most effective antibiotics in isolated strains. All strains were ascertained to be methicillin and amoxicillin/clavulanic acid resistant.

Determining the Biofilm Forming Gene Profile of Staphylococcus aureus Clinical Isolates via Multiplex Colony PCR Method.

BACKGROUND: Among hospitalized patients, Staphylococcus aureus (S. aureus) infections pose a serious health threat. The present study investigated the frequency of biofilm forming genes among clinical isolates S. aureus and their susceptibility to antibiotics. METHODS: The clinical samples were analyzed via standard biochemical assays for identifying different bacterium, which was then confirmed using the multiplex colony PCR method. Those samples identified as S. aureus were examined for the presence of the cna, fnbA, fnbB and pvl genes. The antibiotic susceptibility of the S. aureus isolates was then tested. RESULTS: Using the standard biochemical assay approach, 54 S. aureus strains were identified. However, when using the multiplex PCR method 50 S. aureus strains were identified among the clinical samples. The in vitro biofilm formation assays determined 3 (6%) strains of S. aureus to be strong biofilm forming, 15 (30%) of the isolates were determined to be moderate biofilm forming and, 32 (64%) were determined to be weak biofilm forming. Among the isolated strains, the specific frequencies of the biofilm forming genes were determined to be 31 (62%) for cna, 35 (70%) for fnbA, 13 (26%) for fnbB and 1 (2%) for pvl. In 11 (22%) of the isolated strains fnbA, fnbB and cna genes were all present. All strains were determined to be penicillin, amoxicillin and clavulanic acid resistant. CONCLUSION: Due to the increase of the antibiotic resistance in biofilm producing S. aureus strains, rapid identification of antibiotic resistance can help to eliminate the infection effectively.