MecA and ermA Gene Discrepancy from Their Phenotypic Profile in Staphylococcus aureus Isolates

Year 2022, Volume: 12 Issue: 01, 6 - 11, 15.03.2022

Shreya Mahesh Rajkumar Kalyan Prashant Gupta Sheetal Veram Vimala Venkatesh Piyush Tripathi

https://doi.org/10.5799/jmid.1085907

Abstract

ABSTRACT
Objectives: Staphylococcus aureus is one of the most important bacterial pathogens in clinical practice and a primary diagnostic focus for the routine microbiology laboratory. The aim of this study was to find out the phenotypic and genotypic variations in Staphylococcus aureus isolates at a tertiary care center in Lucknow.
Methods: 140 clinical isolates of S. aureus were taken in the study. Kirby–Bauer disc diffusion method was performed to identify antibiotic susceptibility testing, phenotypically methicillin-resistant Staphylococcus aureus (MRSA) were identified by using cefoxitin disc (30 μg), and inducible clindamycin resistance was identified by the presence of D-shaped zone around clindamycin and by using conventional PCR method mecA and ermA genes were identified.
Results: Out of 140 clinical isolates S. aureus, 93 (66.4%) were MRSA, and 47 (33.6%) were methicillin-sensitive Staphylococcus aureus (MSSA). Phenotype iMLSb was 41 (29.3%), cMLSb phenotype was 37 (26.4%), mecA gene was present in 84 (60%), and none of the samples showed ermA gene positivity.
Conclusion: As we know, the presence of the mecA gene is the major evidence for the detection of MRSA isolates. Their presence in low numbers opens the door to search for other mechanisms that may compete with mecA gene in producing resistance phenomenon. The absence of ermA gene in strains S. aureus with iMLSb and cMLSb phenotypes concluded that some other erm gene is responsible for this MLS type of resistance. Due to the frequency of MRSA strains showing the iMLSb phenotype, the use of clindamycin in erythromycin-resistant strains cannot be recommended due to the high possibility of failure in treatment with this antibiotic. J Microbiol Infect Dis 2021; 11(4):6-11.

Keywords

Staphylococcus aureus, mecA gen, ermA gene, MRSA, MLSb phenotype

References

• 1. Verma S, Joshi S, Chitnis V, Hemwani N, Chitnis D. Growing problem of methicillin resistant Staphylococci, Indian scenario. Indian J Med Sci 2000; 54(12):535-40.
• 2. Naimi TS, LeDell KH, Como-Sabetti K, et al. Comparison of community-and health-care–associated methicillin-resistant Staphylococcus aureus infection. JAMA 2003; 290:2976–84.
• 3. Charlebois, ED, Perdreau-Remington F, Kreisworth B, et al. Origins of community strains of methicillin-resistant Staphylococcus aureus. Clin Infect Dis 2004; 39:47–54.
• 4. Coyle EA, Lewis RL, Prince RA. Influence of clindamycin on the release of Staphylococcus aureus a-hemolysin from methicillin resistant S. aureus: could MIC make a difference [abstract 182]? Crit Care Med 2003; 31 (Suppl):A48.
• 5. Clinical Laboratory Standards Institute (CLSI) guidelines. Performance standards for antimicrobial susceptibility testing: twenty second informational supplement. CLSI document M100-S22. Clinical and Laboratory Standards Institute. Pennsylvania; Wayne; 2019.
• 6. Roberts, MC, Sutcliffe J, Courvalin P, Jensen LB, Rood J, Seppala H. Nomenclature for macrolide-lincosamide-streptogramin B resistance determinants. Antimicrob. Agent Chemother 1999; 43:2823–2830.
• 7. Isenberg HD. Clinical microbiology procedures handbook. 2nd ed. Washington D.C.: ASM Press; 2004.
• 8. Farrow KA, Lyras D, Rood JI. The macrolide-lincosamide-streptogramin B resistance determinant from Clostridium difficile 630 contains two erm(B) genes. Antimicrob Agents Chemother 2000; 44(2):411-413.
• 9. Diwakar MK, Goyal A, Verma S, Srivastava N. Prevalence of Inducible Clindamycin Resistance among Nasal Carriage Staphylococcus aureus among Healthy Population. Int J Curr Microbiol App Sci 2018; 7(5): 2509-2517.
• 10. Mokta KK, Verma S, Chauhan D, et al Inducible Clindamycin Resistance among Clinical Isolates of Staphylococcus aureus from Sub Himalayan Region of India. J Clin Diagn Res 2015; 9(8):DC20-23.
• 11. Sah P, Khanal R, Lamichhane P, Upadhaya S, Lamsal A, Pahwa VK. Inducible and constitutive clindamycin resistance in Staphylococcus aureus: An experience from Western Nepal. Int J Biomed Res 2015; 6(3); 16-19.
• 12. Kumar A, Kumar A. Prevalence of Methicillin Resistant Staphylococcus aureus (MRSA) In A Secondary Care Hospital In North Eastern Part of India. Archiv Infect Dis & Therap 2018; 2(1):1-2.
• 13. Shetty J, Afroz Z. Prevalence of constitutive and inducible clindamycin resistance among clinical isolates of Staphylococcus aureus in a tertiary care institute in North India. Int J Res Med Sci 2017; 5(7):3120-3125.
• 14. BS. Reddy,S. Basak, S. Das, Kaushik P. inducible clindamycin resistance-Staphylococcus aureus and its therapeutic-implications; Int J Curr Researc 2017; 9 (10): 59930-59933.
• 15. Sexena S, Singh T, Rakshit P, Dutta R, Gupta RK. Prevalence of inducible clindamycin resistance in Staphylococcus aureus at a tertiary care hospital: implications for clinical therapy. Int J Curr Microbiol App Sci 2014; 3(3):720-725.
• 16. Davoodi NR, Jalil V, Harz N, Hajrafi A, Rajaei B, Gerayesh-Nejad S. Molecular detection of methicillin resistant Staphylococcus aureus (MRSA) and methicillin resistant coagulase negative Staphylococcus (CoNS) in Iran. Afr J Microbiol Res 2012; 6: 3716.
• 17. Alli OA, Ogbolu DO, Shittu AO, Okorie AN, Akinola JO, Daniel JB. Association of virulence genes with mecA gene in Staphylococcus aureus isolates from Tertiary Hospitals in Nigeria. Indian J Pathol Microbiol 2015; 58:464-471.
• 18. Kareem SM, Al-Jubori SS, Ali M. Prevalence of erm Genes among Methicillin Resistant Staphylococcus aureus MRSA Iraqi Isolates. Int J Curr Microbiol App Sci 2015; 4(5):575-585.
• 19. Tandon N, Kulkarni M, Sowmyags, tabassum F, Akhtar M. Prevalence of inducible clindamycin resistance in clinical isolates of methicillin-resistant Staphylococcus aureus mediated through gene ermC expression. Asain J Pharmaceutic Clin Res 2018; 11(9):106-109.
• 20. Rajkumar S, Sistla S, Manoharan M, et al. Prevalence and genetic mechanisms of antimicrobial resistance in Staphylococcus species: A multicentre report of the Indian council of medical research antimicrobial resistance surveillance network. Indian J Med Microbiol 2017; 35(1):53-60.