Introduction: Resistance to methicillin in staphylococci is mediated by an altered penicillin-binding protein (PBP2a), which is encoded by the mecA gene and confers resistance to most of the current β-lactam antimicrobial agents. Methicillin-resistant S. aureus (MRSA) infections account for 40-60% of all nosocomial (hospital acquired) S. aureus infections in many centers across the world. HCWs are likely to play a large role in MRSA transmission. Screening is a useful technique to identify the reservoir, initiate contact precautions and eradication measures. The conventional screening method is a multistep process. The chrome agar method is not only a single step process but also easier one. By this we save time and decrease the workload. This Cross-sectional Analytical study was carried out to look for the utility of chromogenic media as screening tool for early detection of MRSA strains from the nasal carriage of healthcare workers in tertiary care hospital in central India. 

Methods: Thirty non repetitive samples each from four groups of health care provider i.e. Consultants, Residents, Nursing staff & Cleaning Staff were collected after informed consent and ethical clearance. Samples from anterior nares were processed for isolation of S. aureus and detection of MRSA by conventional and by Chromagar. Data maintained in Microsoft office Excel was analyzed with statistical tools like tests of proportion & Chi Square test for significance.

Results: By conventional method, out of 120 samples 68 were S. aureus of which 26(21.66%) were MRSA. Chrome agar detected 27(22.5%) MRSA.  Time required for MRSA detection conventionally was 48 hours while by Chrome agar detection was in 24 hours for 24 (88.88%) isolates and 48 hours for 03 isolates.

Conclusion: Chrom agar MRSA is highly specific and sensitive to detect MRSA. In majority of cases MRSA detection was within 24 hours.

Keywords: Chrom agar, Nasal colonization, MRSA, PBP2a, Health care provider, Hospital Acquired Infections

Key Messages: The control and prevention of the infection ascribed to MRSA can only be achieved when there is a regular screening of carriers among healthcare providers thus preventing the spread of MRSA in hospital settings as well as community. Chrome agar can be a better option to conventional method as it is highly sensitive and specific and time saving.

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Dr Avinash Laghawe

Professor and Head, Department of Microbiology

People’s College of Medical Sciences & Research Centre, Bhanpur Road, Bhopal (MP)