Antibiotic Susceptibility, Biofilm Production, and Detection of <i>mec</i>A Gene among <i>Staphylococcus aureus</i> Isolates from Different Clinical Specimens

oleh: Upama Gaire, Upendra Thapa Shrestha, Sanjib Adhikari, Nabaraj Adhikari, Anup Bastola, Komal Raj Rijal, Prakash Ghimire, Megha Raj Banjara

Format: Article
Diterbitkan: MDPI AG 2021-11-01

Deskripsi

The increasing incidence of methicillin-resistant and biofilm-forming <i>S. aureus</i> isolates in hospital settings is a gruesome concern today. The main objectives of this study were to determine the burden of <i>S. aureus</i> in clinical samples, assess their antibiotic susceptibility pattern and detect biofilm formation and <i>mec</i>A gene in them. A total of 1968 different clinical specimens were processed to isolate <i>S. aureus</i> following standard microbiological procedures. Antibiotic susceptibility test of the isolates was performed by Kirby–Bauer disc-diffusion method following CLSI guidelines. Biofilm was detected through tissue culture plate method. Methicillin-resistant <i>S. aureus</i> (MRSA) isolates were screened using cefoxitin (30 µg) discs and <i>mec</i>A gene was amplified by conventional polymerase chain reaction (PCR). Of 177 bacterial growth, the prevalence of <i>S. aureus</i> was 15.3% (<i>n</i> = 27). MRSA were 55.6% (15/27) and 44% (12/27) exhibited multidrug resistance (MDR). There was no significant association between methicillin resistance and MDR (<i>p</i> > 0.05). Both MRSA and MSSA were least sensitive to penicillin (100%, 75%) followed by erythromycin (86.6%, 66.6%). Most of the MRSA (93.4%) were susceptible to tetracycline. All <i>S. aureus</i> isolates were biofilm producers—19 (70%) were weak and only one (4%) was a strong biofilm producer. The strong biofilm-producing MSSA was resistant to most of the antibiotics except cefoxitin and clindamycin. None of the MSSA possessed <i>mec</i>A gene while 8 (53.3%) MRSA had it. More than half of <i>S. aureus</i> isolated were MRSA. High incidence of multidrug resistance along with capacity to form biofilm among clinical isolates of <i>S.</i><i>aureus</i> is a matter of apprehension and prompt adoption of biosafety measures is suggested to curb their dissemination in the hospital environments.