Prevalence and Molecular Characterisation of Methicillin-Resistant Coagulase Negative Staphylococci (MR-CoNS) Isolated from Nasal Carriers of End Stage Renal Disease Patients- A Prospective Study
Dr. Padma Krishnan,
Assistant Professor (Retd), Department of Microbiology, Dr. ALM PG Institute of Basic Medical Sciences, University of Madras, Taramani, Chennai-113, Tamil Nadu, India.
Introduction: Patient-to-patient transmission of resistant strains has caused a rapid increase in the prevalence of antimicrobial resistance in recent years. Infection has become a major cause of morbidity and is the second most common cause of death in patients receiving haemodialysis. Compared to methicillin-resistant Staphylococcus aureus (MRSA) transmission, less is known regarding the epidemiology of methicillin-resistant coagulase-negative staphylococci (MR-CoNS) in health care facilities. Patients receiving haemodialysis are at particular risk for the development of invasive infections caused by MR-CoNS.
Aim: To detect the prevalence of antibiotic resistance genes among nasal carriage of MR-CoNS from End Stage Renal Disease (ESRD) patients and hospital personnel.
Materials and Methods: This cross-sectional prospective study was conducted over a period of two months (August-September 2013) at the nephrology unit of a tertiary care hospital, Chennai, Tamil Nadu, India. A total of 145 anterior nasal swabs were collected from 115 patients and 30 hospital personnel. Screening of methicillin resistance was done by using phenotypic and genotypic method. Speciation of MR-CoNS was done by conventional biochemical methods. Molecular detection of various antibiotic resistant genes and staphylococcal cassette chromosome mec (SCCmec) type (I-V) was determined by PCR based method.
Results: Among 79 MR-CoNS isolates, S.epidermidis was the predominant species and highest resistance was seen towards co-trimoxazole (29; 36.7%) followed by tetracycline (18; 23%), gentamycin (17; 21.5%), fusidic acid (14; 18%) and linezolid (2; 2.5%). Among the SCCmec types, type IV (n=27) was the predominant type followed by type I (n=18) and type V (n=15), while 17 isolates had two types including I+V (n=8), IV+III (n=6), II+V (n=3).
Conclusion: The findings of our study strongly suggest the need for the establishment of infection control program measures in order to prevent and reduce MR-CoNS infections in ESRD patients.