Celbenin, or methicillin, which was discovered by Beecham in 1961, was touted then as the ultimate staphylococcidal, being effective against penicillinase producing strains, but soon after, strains resistant to it were also discovered, initially in the hospital setup, and later, in the community setup. This organism, christened as Methicillin Resistant Staphylococcus Aureus, or MRSA, has gone on to become a scourge in recent times. Western literature, especially from the US, is rife with reports of morbidity and mortality from this particularly aggressive organism.
There has been a gradual increase in the number of reports describing MRSA in India over the years. Varied rates of MRSA infection have been reported, from rural to urban, from pediatric to geriatric, and from simple skin infections to serious sepsis cases, in the Indian medical literature of late. Several studies have reported the prevalence of MRSA in healthcare workers, particularly among those who were involved in critical care areas, as between 10 and 14.3%. The isolation rates for MRSA from outpatients, ward inpatients and intensive care units (ICUs) were 27%, 49% and 47%, respectively, in studies reported in 2009. The majority of S. aureus isolates were obtained from patients with skin and soft tissue infections, followed by those suffering from bloodstream infections and respiratory infections. According to a recent study, the frequency of 45% of S. aureus clinical isolates being methicillin-resistant in India in the early 2010s is similar to what has been reported in the rest of the Asian countries (41.9% in Pakistan, 45.8% in China, 41% in Japan, 35.3% in Singapore and 55.9% in Taiwan), except Hong Kong, Indonesia (28% each) and South Korea (>70%). Similar to global trends, however, MRSA in India has been observed to be of geographically diverse origins.
Initial studies of clinical samples from hospitals showed that the incidence of the hospital acquired organism, HA-MRSA was as low as 6.9% in 1988, but increased to 27% to 47%, across several cities, by the late 1990s. Infections with the community acquired CA-MRSA have been reported in school children and in healthy individuals both from rural and urban areas.
The first report of characterization of CA-MRSA from India was for an isolate obtained from a patient suffering from osteomyelitis, pyomyositis and pneumonia in Bengaluru. The strain was found to be of the Sequence Type ST772, also called the Bengal Bay clone. A recent study investigating clinical samples from inpatients (from Bengaluru, Mumbai, Hyderabad and Delhi) as well as nasal carriage by rural and urban healthy volunteers revealed that ST22 and ST772 were the dominant MRSA clones. It was also noted that other minor clones belonging to ST1208 (CC8) and ST672 were emerging. The majority of the isolates also carried genes for Panton Valentine Leukocidin as well as many other toxins. It is noteworthy that CA-MRSA clone ST772 is rare in other Asian countries.
In addition to ST772 and ST22, another new emerging clone, ST672, which has not been reported elsewhere in Asia, has been isolated primarily from India. This organism has been found to be transferred across the globe by travellers from India. In a study titled “Airport Door Handles and the Global Spread of Antimicrobial-resistant Bacteria: A Cross Sectional Study”, published in Clinical Microbiology and Infection last year, Frieder Schaumburg (University Hospital Münster, Germany), the lead author, notes that 400 toilet door handles in 136 airports in 59 countries were sampled and found to harbour the ST672 strains. 60% of the samples were taken in the men’s room with 40% in the women’s toilets and, on average, the time between sampling and culture in the lab was seven days. Samples were taken in the airport of arrival (80.75%) a stop-off point (2.75%), or the destination (16.5%), and the results make fascinating reading.
In the light of the aforesaid findings, the awareness of the existence of this organism, and its special strains in India, is a must amongst Dermatologists, since it is we, along with the surgeons, who encounter them most often. The susceptibility of this organism to our older antibiotics Doxycycline, Co-trimoxazole and Clindamycin, and Fusidic acid, particularly in the community setup is a heartening point to note. The HA strains, if they do not respond to the already mentioned antibacterials, will have to be treated with the newer antibiotics, viz., Ceftaroline, ceftobiprole, tidezolid, dalbavancin, otrivancin, or a combination of beta lactamase with vancomycin or daptomycin.:)