Transmission dynamics of methicillin-resistant Staphylococcus aureus in a medical intensive care unit in India.

• Main Authors: Christopher, Solomon, Verghis, Rejina Mariam, Antonisamy, Belavendra, Sowmyanarayanan, Thuppal Varadachari, Brahmadathan, Kootallur Narayanan, Kang, Gagandeep, Cooper, Ben Symons
• Format: Article
• Language: English
• Published: 2015
• Subjects: India; Methicillin-resistant; Staphylococcus aureus; Open Access article
• Online Access: https://repository.li.mahidol.ac.th/handle/123456789/801
• Institution: Mahidol University

BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) is a global pathogen and an important but seldom investigated cause of morbidity and mortality in lower and middle-income countries where it can place a major burden on limited resources. Quantifying nosocomial transmission in resource-poor settings is difficult because molecular typing methods are prohibitively expensive. Mechanistic statistical models can overcome this problem with minimal cost. We analyse the transmission dynamics of MRSA in a hospital in south India using one such approach and provide conservative estimates of the organism's economic burden. METHODS AND FINDINGS: Fifty months of MRSA infection data were collected retrospectively from a Medical Intensive Care Unit (MICU) in a tertiary hospital in Vellore, south India. Data were analysed using a previously described structured hidden Markov model. Seventy-two patients developed MRSA infections and, of these, 49 (68%) died in the MICU. We estimated that 4.2% (95%CI 1.0, 19.0) of patients were MRSA-positive when admitted, that there were 0.39 MRSA infections per colonized patient month (0.06, 0.73), and that the ward-level reproduction number for MRSA was 0.42 (0.08, 2.04). Anti-MRSA antibiotic treatment costs alone averaged $124/patient, over three times the monthly income of more than 40% of the Indian population. CONCLUSIONS: Our analysis of routine data provides the first estimate of the nosocomial transmission potential of MRSA in India. The high levels of transmission estimated underline the need for cost-effective interventions to reduce MRSA transmission in hospital settings in low and middle income countries.