Emergence of the fact that community acquired MRSA clones are different from healthcare-associated MRSA has disproved that hospitalization is the sole factor for MRSA, and also indicates that the risk factors are also present in the community which select out the resistant Staphyloccocus aureus strains.

In the study published in the present issue of Indian Pediatrics, Senthilkumar and colleagues [1] have studied the clinical predictors and risk factors associated with MRSA in children. They conclude that clinical characteristics of MRSA do not differ from MSSA infections. Further, they report that MRSA is more likely to be isolated from children with high total leucocyte count. In their study, 80% of the total MRSA isolates were community acquired MRSA. It would have been useful if the authors had provided more clear definitions of community acquired MRSA, healthcare-associated MRSA and healthcare-associated CO phenotype in their paper.

Overall, healthcare-associated MRSA still remains more prevalent, and is also resistant to more classes of antibiotics, therefore limiting the therapeutic options. Healthcare-associated MRSA is more commonly responsible for blood stream infections (BSI) and skin and soft tissue infections (SSTI). A study conducted in three teaching hospitals in North India [2] – to understand the risk factors associated with SSTI due to MRSA – reported an overall prevalence of MRSA causing SSTIs as 31.2%. A stepwise multiple logistic regression analysis adjusting for the differences among the hospitals indicated that factors like longer duration of hospital stay, presence of dermatosis, osteomyelitis and recent use of aminoglycosides and clindamycin were significantly associated with MRSA-SSTIs.

In a study evaluating risk factors for intensive care unit (ICU) acquired BSI due to MRSA [3], duration of hospitalization in ICU, simultaneous MRSA colonization in another patient in the ICU, prior use of antibiotics, and presence of central line were reported as independent risk factors. Duration of hospital stay has emerged as a common risk factor for acquiring not only MRSA but also multi-drug resistant (MDR) gram negative bacteria from most of the published literature. In turn, healthcare-associated infections determine the length of hospital stay [4]. The presence of skin lesions or infections or dermatosis can also be related to increased chances of colonization with MRSA, and more likelihood of prior antibiotic therapy. In a multicenter retrospective cohort study [5], a significant dose-effect relationship was seen between the prescription of antimicrobial drugs and MRSA infections.

There are studies that suggest a significant association of MRSA colonization as risk factor for subsequent infections with MRSA in hospitals as well as community. This is the reason that decolonization with chlorhexidine has been used as a strategy to prevent MRSA infections in hospital settings [6]. Other studies have also shown that nasal carriage is a risk factor in also in community acquired as well as healthcare-associated MRSA [7].

Finally, it is the local epidemiology and resistance profile of bacteria causing infections that is important while making the choice of empirical antibiotics. Therefore, studies on risk factors or prevalence of MRSA infections must have clear definitions for community acquired MRSA and healthcare-associated MRSA, and also look at the antimicrobial susceptibility profiles. Community acquired MRSA have more options of antibiotics, being susceptible to clindamycin, fluoroquinolones, cotrimoxazole and erythromycin, unlike healthcare-associated MRSA where vancomycin and linezolid are the limited choices [8]. It is also important to correctly identify MSSA from MRSA as beta-lactams have superior activity against S. aureus and therefore vancomycin should be avoided if MSSA is confirmed. The need to judiciously use vancomycin is not only to prevent emergence to vancomycin-intermediate S. aureus or vancomycin-resistant S. aureus but also to reduce the collateral damage in tertiary care settings where emergence of vancomycin-resistant enterococcus is linked to the use of vancomycin [9].

To be able to effectively control the spread of MRSA in any setting, it is imperative to know its risk factors and the modes of spread. There is now enough evidence that transmission by hands remains the most important method for acquisition and spread of MRSA in hospitals [10]. Strategies focusing on hand hygiene and use of standard precautions have shown a significant reduction in MRSA transmission [10]. This will go a long way in reducing the length of hospital stay, antibiotic use and the emergence of multidrug resistant bacteria.

Funding: None; Competing interests: None stated.

1. Senthilkumar K, Biswal N, Sistla S. Risk factors associated with methicillin-resistant Staphylococcus aureus infection in children. Indian Pediatr. 2015;52:31-3.

2. Gadepalli R, Dhawan B, Kapil A, Sreenivas V, Jais M, Gaind R, et al. Clinical and molecular characteristics of nosocomial meticillin-resistant Staphylococcus aureus skin and soft tissue isolates from three Indian hospitals. J Hosp Infect. 2009;73:253-63.

3. Oztoprak N, Cevik MA, Akinci E, Korkmaz M, Erbay A, Eren SS, et al. Risk factors for ICU-acquired methicillin-resistant Staphylococcus aureus infections. Am J Infect Control. 2006;34:1-5.

4. Gupta A,　Kapil A, Lodha R, Kabra SK, Sood S, Dhawan B, et al. Burden of healthcare-associated infections in a paediatric intensive care unit of a developing country: A single centre experience using active surveillance. J Hosp Infect. 2011;78:323-6.

5. Catry B, Latour K, Jans B, Vandendriessche S, Preal R, Mertens K, et al. Risk factors for methicillin resistant Staphylococcus aureus: a multi-laboratory study. PLoS One. 2014;9:e89579.

6. Huang SS, Septimus E, Kleinman K, Moody J, Hickok J, Avery TR, et al; CDC Prevention Epicenters Program; AHRQ DECIDE Network and Healthcare-Associated Infections Program. Targeted versus universal decolonization to prevent ICU infection. N Engl J Med. 2013;368:2255-65.

7. von Eiff C, Becker K, Machka K, Stammer H, Peters G. Nasal carriage as a source of Staphylococcus aureus bacteremia. Study Group. N Engl J Med. 2001;344:11-6.

8. Dhawan B, Rao C, Udo EE, Gadepalli R, Vishnubhatla S, Kapil A. Dissemination of methicillin-resistant Staphylococcus aureus SCCmec type IV and SCCmec type V epidemic clones in a tertiary hospital: Challenge to infection control. Epidemiol Infect. 2014:1-11.

9. Dhawan B, Gadepalli R, Rao C, Kapil A, Sreenivas V. Decreased susceptibility to vancomycin in meticillin-resistant Staphylococcus aureus: A 5 year study in an Indian tertiary hospital. J Med Microbiol. 2010;59:375-6.