Association of Antibacterial Susceptibility Profile with the Prevalence of Genes Encoding Efflux Proteins in the Bangladeshi Clinical Isolates of <i>Staphylococcus aureus</i>

• Main Authors: Tanjina Akter Suma (Author), Nushrat Alam (Author), Sheikh Zahir Raihan (Author), Md. Al Zahid (Author), Shankar Chandra Mandal (Author), Fahrin Jahan Suchana (Author), Ripa Kundu (Author), Anwar Hossain (Author), Md. Abdul Muhit (Author)
• Format: Book
• Published: MDPI AG, 2023-02-01T00:00:00Z.
• Subjects: article
• Online Access: Connect to this object online.
• Notes: 10.3390/antibiotics12020305; 2079-6382
• Keywords: <i>Staphylococcus aureus</i>; MRSA; efflux pump genes; antibiotic resistance; MDR <i>S. aureus</i>; Therapeutics. Pharmacology; RM1-950
• Source: Antibiotics, Vol 12, Iss 2, p 305 (2023)

Expelling antibiotic molecules out of the cell wall through multiple efflux pumps is one of the potential mechanisms of developing resistance against a wide number of antibiotics in <i>Staphylococcus aureus</i>. The aim of this study was to investigate the association between the antibiotic susceptibility profile and the prevalence of different efflux pump genes i.e., <i>norA, norB, norC, mepA, sepA, mdeA, qacA/B</i>, and <i>smr</i> in the clinical isolates of <i>S. aureus</i>. Sixty clinical isolates were collected from a tertiary level hospital in Bangladesh. The disc diffusion method using ten antibiotics of different classes was used to discern the susceptibility profile. polymerase chain reaction (PCR) was employed to observe the resistance patterns and to detect the presence of plasmid and chromosomal encoded genes. Among the clinical isolates, 60% (36 out of 60) of the samples were Methicillin-resistant <i>Staphylococcus aureus</i> (MRSA), whereas 55% (33 out of 60) of the bacterial samples were found to be multi-drug resistant. The bacteria showed higher resistance to vancomycin (73.33%), followed by ciprofloxacin (60%), cefixime (53.33%), azithromycin (43.33%), and amoxicillin (31.67%). The prevalence of the chromosomally-encoded efflux genes <i>norA</i> (91.67%), <i>norB</i> (90%), <i>norC</i> (93.33%), m<i>epA</i> (93.33%), s<i>epA</i> (98.33%), and <i>mdeA</i> (93.33%) were extremely high with a minor portion of them carrying the plasmid-encoded genes <i>qacA/B</i> (20%) and <i>smr</i> (8.33%). Several genetic combinations of efflux pump genes were revealed, among which <i>norA + norB + norC + mepA + sepA + mdeA</i> was the most widely distributed combination among MRSA and MSSA bacteria that conferred resistance against ciprofloxacin and probably vancomycin. Based on the present study, it is evident that the presence of multiple efflux genes potentiated the drug extrusion activity and may play a pivotal role in the development of multidrug resistance in <i>S. aureus</i>.