Molecular Characterization and Histopathological Correlation of Antibiotic Resistance Genes in Clinical Isolates of MRSA in Pakistani Hospitals
Keywords:
Antibiotic Resistance, Histopathology, Methicillin-Resistant Staphylococcus aureus (MRSA)Abstract
Background: Methicillin-resistant Staphylococcus aureus (MRSA) is a major public health concern worldwide due to its multidrug resistance and associated morbidity. In Pakistan, hospital-based prevalence remains high, yet limited data exist on the molecular determinants of resistance and their correlation with tissue pathology.
Objective: To characterize antibiotic resistance genes in clinical isolates of MRSA from Pakistani hospitals and to assess their correlation with histopathological features of infection.
Methodology: A cross-sectional study was conducted from January to December 2025 in three tertiary-care hospitals. A total of 406 clinical MRSA isolates were included. Standard microbiological procedures and PCR assays were used to detect resistance genes. Histopathological specimens from corresponding infection sites were examined for necrosis, abscess formation, vascular invasion, and chronic inflammation. Data were analyzed using SPSS 25. Associations were tested with Chi-square, t-test, and multivariable logistic regression.
Results: All isolates carried mecA, while mecC was present in 3%. Among accessory genes, ermA (31%), ermC (24.1%), tetK (20.9%), tetM (18.2%), and aac(6’)-aph(2’’) (16.5%) were frequent, whereas vanA (2.2%) and vanB (0.7%) were rare. Gene-positive isolates exhibited significantly higher rates of severe necrosis (p < 0.001), abscess formation (p = 0.002), and vascular invasion (p = 0.004). Logistic regression identified ermA (p = 0.001), tetM (, p = 0.041), and prior antibiotic exposure (p = 0.046) as independent predictors of severe histopathological changes.
Conclusion: MRSA in Pakistani hospitals demonstrates widespread mecA carriage with frequent accessory resistance genes, which correlate with more severe tissue pathology..
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Nandhini P, Kumar P, Mickymaray S, Alothaim AS, Somasundaram J, Rajan M. Recent developments in methicillin-resistant Staphylococcus aureus (MRSA) treatment: a review. Antibiotics. 2022;11(5):606.
Yildiz SC. Staphylococcus aureus and methicillin resistant Staphylococcus aureus (MRSA) carriage and infections. Staphylococcal infections-recent advances and perspectives: IntechOpen; 2022.
Mahjabeen F, Saha U, Mostafa MN, Siddique F, Ahsan E, Fathma S, et al. An update on treatment options for methicillin-resistant Staphylococcus aureus (MRSA) bacteremia: a systematic review. Cureus. 2022;14(11).
Lynch JP, Zhanel GG. Escalation of antimicrobial resistance among MRSA part 1: focus on global spread. Expert Review of Anti-Infective Therapy. 2023;21(2):99-113.
Mohamad Farook NA, Argimón S, Abdul Samat MN, Salleh SA, Sulaiman S, Tan TL, et al. Diversity and dissemination of methicillin-resistant Staphylococcus aureus (MRSA) genotypes in Southeast Asia. Tropical Medicine and Infectious Disease. 2022;7(12):438.
Bukhari SUP, Aziz F, Shamim M, Kalhoro IA, Ali K, Perveen A, et al. Challenges and Strategies for MRSA Control: A Case of Hospitals in Karachi. Journal of Asian Development Studies. 2025;14(2):453-67.
Preeja PP, Kumar SH, Shetty V. Prevalence and characterization of methicillin-resistant Staphylococcus aureus from community-and hospital-associated infections: a tertiary care center study. Antibiotics. 2021;10(2):197.
Lade H, Kim J-S. Molecular determinants of β-lactam resistance in methicillin-resistant Staphylococcus aureus (MRSA): an updated review. Antibiotics. 2023;12(9):1362.
Yang D, Heederik DJ, Scherpenisse P, Van Gompel L, Luiken RE, Wadepohl K, et al. Antimicrobial resistance genes aph (3′)-III, erm (B), sul2 and tet (W) abundance in animal faeces, meat, production environments and human faeces in Europe. Journal of Antimicrobial Chemotherapy. 2022;77(7):1883-93.
Moriarty TF, Metsemakers W-J, Morgenstern M, Hofstee MI, Vallejo Diaz A, Cassat JE, et al. Fracture-related infection. Nature Reviews Disease Primers. 2022;8(1):67.
Hafeez R, Chughtai A, Aslam M. Prevalence and antimicrobial susceptibility of methicillin resistant Staphylococcus aureus (MRSA). International Journal of Pathology. 2018:10-6.
Khan S, Marasa BS, Sung K, Nawaz M. Genotypic characterization of clinical isolates of Staphylococcus aureus from Pakistan. Pathogens. 2021;10(8):918.
Idrees MM, Saeed K, Shahid MA, Akhtar M, Qammar K, Hassan J, et al. Prevalence of mecA-and mecC-associated methicillin-resistant Staphylococcus aureus in clinical specimens, Punjab, Pakistan. Biomedicines. 2023;11(3):878.
Kang HJ, You J-Y, Kim SH, Moon J-S, Kim H-Y, Kim J-M, et al. Characteristics of methicillin-resistant Staphylococcus aureus isolates from bovine mastitis milk in South Korea: molecular characteristics, biofilm, virulence, and antimicrobial resistance. Microbiology spectrum. 2024;12(12):e01197-24.
Sadiq A, Samad M, Saddam, Basharat N, Ali S, Roohullah, et al. Methicillin-resistant Staphylococcus aureus (MRSA) in slaughter houses and meat shops in capital territory of Pakistan during 2018–2019. Frontiers in Microbiology. 2020;11:577707.
Huang L, Zhu L, Yan J, Lin Y, Ding D, He L, et al. Genomic characterization and outbreak investigations of methicillin-resistant Staphylococcus aureus in a county-level hospital in China. Frontiers in Microbiology. 2024;15:1387855.
Agbo MC, Ezeonu IM, Onodagu BO, Ezeh CC, Ozioko CA, Emencheta SC. Antimicrobial resistance markers distribution in Staphylococcus aureus from Nsukka, Nigeria. BMC Infectious Diseases. 2024;24(1):320....
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