Article published in Diseases, MDPI

 

MDPI

Diseases 2021, 9, 80. https://doi.org/10.3390/diseases9040080

 

Antibiotic Susceptibility, Biofilm Production, and Detection of mecA Gene among Staphylococcus aureus Isolates from Different Clinical Specimens

Upama Gaire¹, Upendra Thapa Shrestha¹, Sanjib Adhikari¹, Nabaraj Adhikari¹, Anup Bastola², Komal Raj Rijal^1,*, Prakash Ghimire¹ and Megha Raj Banjara^1,*

¹Central Department of Microbiology, Tribhuvan University, Kirtipur, Kathmandu 44600, Nepal

²Sukraraj Tropical and Infectious Diseases Hospital, Teku, Kathmandu 44600, Nepal; docanup11@gmail.com

 

* Correspondence: komal.rijal@cdmi.tu.edu.np (K.R.R.); megha.banjara@cdmi.tu.edu.np (M.R.B.)

 

ABSTRACT

 The increasing incidence of methicillin-resistant and biofilm-forming S. aureus isolates in hospital settings is a gruesome concern today. The main objectives of this study were to determine the burden of S. aureus in clinical samples, assess their antibiotic susceptibility pattern and detect biofilm formation and mecA gene in them. A total of 1968 different clinical specimens were processed to isolate S. aureus 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 S. aureus (MRSA) isolates were screened using cefoxitin (30 μg) discs and mecA gene was amplified by conventional polymerase chain reaction (PCR). Of 177 bacterial growth, the prevalence of S. aureus was 15.3% (n= 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 (p > 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 S. aureus 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 mecA gene while 8 (53.3%) MRSA had it. More than half of S. aureus isolated were MRSA. High incidence of multidrug resistance along with capacity to form biofilm among clinical isolates of S. aureus is a matter of apprehension and prompt adoption of biosafety measures is suggested to curb their dissemination in the hospital environments.

 

Keywords: S. aureus; antibiotic susceptibility; MRSA; mecA gene; biofilm

 

Citation: Gaire, U.; Shrestha, U.T.; Adhikari, S.; Adhikari, N.; Bastola, A.; Rijal, K.R.; Ghimire, P.; Banjara, M.R. Antibiotic Susceptibility, Biofilm Production and Detection of mecA Gene among Staphylococcus aureus Isolates from Different Clinical Specimens. Diseases 2021, 9, 80. https://doi.org/10.3390/diseases9040080

 

Academic Editor: St Patrick Reid

Received: 9 October 2021

Accepted: 29 October 2021

Published: 1 November 2021

 

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