Genotyping of Methicillin-Resistant Staphylococcus aureus Strains from Two Hospitals in Bangalore, South India

Abstract

Methicillin-resistant Staphylococcus aureus (MRSA) is a major nosocomial pathogen in India, and up to 70% methicillin resistance has been reported from hospitals in various parts of India. Hospitals use phenotyping for the most part, and molecular genotyping is not done. Here we report on the genotyping of 82 single-patient isolates from two hospitals in Bangalore, South India, for the first time. Most of the strains possessed type III or IIIA staphylococcal cassette chromosome (SCCmec) cassettes, and we did not detect strains with type I, IA, or II cassettes. Most isolates also contained the type III cassette chromosome recombinase (ccr) AB region. Multilocus sequence typing (MLST) and staphylococcal protein A (spa) typing of a selected number of isolates have been carried out. Although most isolates that were chosen for MLST and spa typing had the same patterns, they were quite diverse in their pulsed-field gel electrophoresis (PFGE) patterns. PFGE, MLST, and spa typing of the Indian strains revealed that they are related to the previously described Hungarian and Brazilian clones.Methicillin-resistant Staphylococcus aureus (MRSA) is an important pathogen causing pyogenic, disseminated, and toxinmediated infections (7,18,20). MRSA bacteremia is associated with significantly higher mortality than is known for methicillin-susceptible S. aureus bacteremia (6). Genotyping data from large international studies have shown that a few clones of MRSA are responsible for the spread of the disease in various parts of the world (4,8,18). Methicillin resistance among S. aureus isolates has reached phenomenal proportions in Indian hospitals, with some cities reporting that up to 70% of the strains are resistant to methicillin (2). About 40 to 50% of S. aureus strains isolated from the burn and trauma wards in hospitals in and around Bangalore, India, are resistant (13). For the present study, clinical isolates have been collected from two major hospitals in the city of Bangalore. Many of these MRSA strains are multidrug resistant, and they are characterized only phenotypically at present. The discriminatory power of most of the phenotypic methods is restricted and ambiguous (10, 21). Molecular typing methods have in the last few years paved the way for sophisticated techniques to track the source and transmission route of bacterial pathogens in hospital outbreaks and have also helped in establishing epidemiological investigations comparing strains across continents (1, 4, 23). Pulsed-field gel electrophoresis (PFGE) has been shown to be highly discriminatory in analyzing hospital outbreaks and tracking genetic changes which occur in a relatively short time, while multilocus sequence typing (MLST) is more suitable for studying long-term genetic variations (5,8,16,24). The aim of this study was to characterize the Indian isolates by PFGE, MLST, and spa typing techniques, which would aid in controlling hospital outbreaks, epidemiological studies, and comparison with international strains. MATERIALS AND METHODS Hospitals.St. Joh...

Draft Genome Sequence of Staphylococcus aureus 118 (ST772), a Major Disease Clone from India

“…Until 2004, hospital-associated MRSA, carrying the staphylococcal cassette chromosome mec (SCCmec) types III and IIIA, was common in India (2). Now, these are being replaced by CA-MRSA strains carrying SCCmec types IV (EMRSA-15) and V (ST772) in Indian hospitals (6,9).…”

Molecular Evidence for Spread of Two Major Methicillin-Resistant Staphylococcus aureus Clones with a Unique Geographic Distribution in Chinese Hospitals

“…On the basis of MLST and SCCmec typing, sequence type 5 (ST5)-MRSA-SCCmec type II (ST5-MRSA-II) was found to be prevalent in South Korea and Japan, while ST239-MRSA-III was prevalent in other Asian countries (1,2,5,17). However, since the number of MRSA isolates from three hospitals in China analyzed in the previous studies was very limited, the data do not represent the nationwide distribution of MRSA genotypes in China (1,5,17).…”

Integrative and Sequence Characteristics of a Novel Genetic Element, ICE 6013 , in Staphylococcus aureus

“…Currently, ST239 is a major cause of MRSA infections in Asian hospitals (5,18,25,37,45,64,74). Pulsed-field gel electrophoresis has detected extensive chromosomal variation in local ST239 populations (3,24,52,72).…”