ISSN: 0973-7510

E-ISSN: 2581-690X

Research Article | Open Access
Anbarasi Kalaiselvan1, Padma Krishnan1 and Esther Mary Selvam2
1Department of Microbiology, Dr. ALM PG IBMS, University of Madras, Chennai – 600 113, Tamil Nadu, India.
2Department of Microbiology, ESIC Hospital, K.K. Nagar, Chennai – 600078, Tamil Nadu, India.
Article Number: 7627 | © The Author(s). 2022
J Pure Appl Microbiol. 2022;16(3):2055-2065.
Received: 17 February 2022 | Accepted: 28 June 2022 | Published online: 24 August 2022
Issue online: September 2022

Staphylococcus haemolyticus is a highly resistant opportunistic pathogen having close genomic relatedness with other virulent species of staphylococci. However, compared to Staphylococcus aureus and Staphylococcus epidermidis, little is known about the resistance genes of S. haemolyticus. The purpose of this study was to characterise antibiotic resistance genes in S. haemolyticus isolates. Standard microbiological techniques were used to identify and confirm 104 S. haemolyticus isolates included in the study. Antibiotic susceptibility testing and D-test were performed, followed by PCR amplification of various resistance determinants (mecA, ermA, ermC, msrA, aac(6′)-Ie-aph(2″), ant(4′)-Ia,aph(3′)-IIIa, tetK, tetM, dfrA, fusB, fusC, fusD and mupA). Methicillin resistance was observed in 93.3% of study isolates. The maximum number of isolates showed resistance to erythromycin (n=79, 76%), followed by ciprofloxacin (n=66, 63.5%) and cotrimoxazole (n=58, 55.8%). In the D-test, 8 isolates showed inducible (iMLSB) and 11 showed constitutive (cMLSB) resistance. Among the resistance determinants, mecA gene (93.3%) was the most prevalent, followed by dfrA (50.5%). Furthermore, aac(6’)-Ie-aph(2’’) and aph(3’)-IIIa combination was observed in 26.9% of isolates, and aac(6’)-Ie-aph(2’’) alone was present in 3.8% of isolates. Among the study isolates, 17.3% exhibited tetK gene, whereas only 1% exhibited tetM; a combination of tetK and tetM was observed in one isolate. The fusB and fusC were present in 11.5% of isolates, and 12.5% of the isolates were positive for mupA. In conclusion, the present study underlines the concern of increasing antibiotic resistance among S. haemolyticus isolates. Avoiding misuse/overuse of antibiotics along with continuous surveillance programs can reduce the spread of antibiotic resistance.


S. haemolyticus Resistance, Multidrug-resistant S. haemolyticus, Antibiotic Drug Resistance

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© The Author(s) 2022. Open Access. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License which permits unrestricted use, sharing, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.