Niranjan
Nepal1, Prakriti Mahara2, Shishir Subedi3,
Komal Raj Rijal1, Prakash Ghimire1, Megha Raj Banjara1,
Upendra Thapa Shrestha1
1Central
Department of Microbiology, Tribhuvan University, Kirtipur, Kathmandu, Nepal
2GoldenGate
International College, Old Baneshwor, Kathmandu, Nepal
3Grande
International Hospital, Dhapasi, Kathmandu, Nepal
CORRESPONDING
AUTHORS: Upendra Thapa Shrestha, Central Department of Microbiology,
Tribhuvan University, Kirtipur, Kathmandu, Nepal, E-mail: upendrats@gmail.com; upendra.thapashrestha@cdmi.tu.edu.np/
Megha
Raj Banjara, Central Department of Microbiology, TU Email: megha.banajara@cdmi.tu.edu.np;
ABSTRACT
Purpose: Methicillin-resistant Staphylococcus
aureus, a common bacterial pathogen causes various infections. The
acquisition of various antimicrobial-resistant genes in S. aureus has
led to the transformation of this bacterium into a superbug. Vancomycin
resistance among MRSA isolates is an emerging threat in empirical therapy of
various infections. The study was hence aimed to find out the susceptibility
status of S. aureus isolates towards vancomycin and detect mecA, vanA
and vanB genes among the isolates.
Methods: A total of 1245 clinical samples from the participants
attending a tertiary care hospital in Kathmandu were processed. S. aureus
isolated from the samples subjected for antibiotic susceptibility pattern using
the modified Kirby-Bauer disk diffusion method. Agar dilution method was used
to determine the minimum inhibitory concentration of vancomycin. The
antibiotic-resistant genes such as mecA, vanA, and vanB among S.
aureus isolates were screened by a conventional polymerase chain reaction.
Results: Of 1245 samples, 80 S. aureus were
identified. Out of which, 47.5% (38/80) were phenotypically confirmed MRSA
isolates. mecA gene was detected in 84.2% (32/38) of MRSA isolates.
10.5% (4/38) were confirmed as vancomycin-intermediate S. aureus (VISA)
by MIC determination. None of the isolates was positive for the vanA
gene; however, two isolates were found to possess the vanB gene. The two
isolates have vancomycin MIC breakpoints of 4-8 μg/mL.
Conclusion: There might be a spreading of vancomycin
resistance among S. aureus, creating serious public health problems.
Therefore, measures to limit vancomycin resistance should be considered in healthcare
facilities as immediately as possible.
Key words:
Staphylococcus aureus, Multidrug-resistant, MRSA, VISA, mecA, vanB
RECEIVED: January 23, 2023. ACCEPTED: May
26, 2023.
TYPE: Original Research
Microbiology Insights
Volume 16: 1–9
© The Author(s) 2023
Article reuse guidelines:
sagepub.com/journals-permissions
DOI: 10.1177/11786361231183675
