DOI: 10.4103/mjbl.mjbl_1214_24 ISSN: 1812-156X

Prevalence of Staphylococcus aureus Biofilm Genes (fnbA, fnbB) from Baghdad Teaching Hospitals and Detection by PCR of the Genes Encoding Resistance to Extended-Spectrum β-Lactams, Erythromycin, and Clindamycin

Rusul Atiyah, Melda DÖLARSLAN, Jaleel Samanje
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Abstract

Background:

Methicillin-resistant Staphylococcus aureus (MRSA) is a major nosocomial infection that can result in several life-threatening syndromes, including pneumonia, endocarditis, wound infections, and bacteremia.

Objectives:

This study aimed to determine the resistance status of MRSA isolates against inducible clindamycin resistance and biofilm production, both phenotypically and genotypically, from different clinical sources.

Materials and Methods:

A total of 200 different clinical samples (wound, urine, burn, and sputum) were collected. All these samples were subjected to classical microbiological testing, which included culturing directly on mannitol salt agar and antibiotic susceptibility test. The cefoxitin 30 (µg) antibiotic was used as a screening antibiotic for detecting the MRSA isolates, as suggested by The clinical & laboratory standards institute. Microtiter plate methods were applied to detect biofilm production in MRSA isolates. Polymerase chain reaction was applied to detect the presence of the MRSA, biofilm, and clindamycin resistance genes.

Results:

From 200 clinical samples, only 50 S. auerus were diagnosed with MRSA, and these isolates showed full resistance against cefoxitin and showed resistance against different antibiotic groups. All MRSA isolates were screened for harboring mecA and blaDHA-1 genes. The result showed all MRSA isolates 50/50 (100%) carried the mecA gene, while only 17/50 isolates carried the blaDHA-1 gene. Considering the phenotyping resistance toward macrolide antibiotic groups, 10/50 (20%), 13/50 (26%), and 25/50 (54%) MRSA isolates showed S, R, and D phenotyping, respectively. For genotypic detection, only six isolates from each group (D, R, and S) phenotype, the ermC gene was highly prevalent in the three groups of MRSA isolates. Regarding biofilm formation, only eight MRSA isolates out of 50 scored as strong biofilm producers, harboring two genes ( fnbA and fnbB ).

Conclusion:

The high frequencies of circulating mecA genes and β -lactam genes demonstrate the necessity of policies for overcoming MRSA problems in clinical specimens. Improper use of antibiotics among patients in Baghdad city may play an essential role in the spread and emergence of antibiotic resistance. Focus on the role of plant extracts in the treatment of MRSA isolates.

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