MRSA circulation among children greatest in hospitals

Apr 29 2013

By Helen Albert, Senior medwireNews Reporter

The hospital environment remains the most common source of methicillin-resistant Staphylococcus aureus (MRSA) bacteria, show results from a systematic review and meta-analysis looking at nasal colonization in different groups of children.

Although there is an overall decreasing trend for MRSA blood-stream infections in the USA and Europe, resistance to methicillin has increased by more than twofold between 1998 and 2007 among S. aureus isolates.

Children are particularly susceptible to hospitalization from MRSA infection and are thought to play a central role in disseminating the bacteria in community and in hospital settings.

To investigate the degree of nasal colonization with MRSA, a factor thought to relate to infection risk, of children in different locations and states of health, Francesco Gesualdo (Ospedale Pediatrico Bambino Gesù, Rome, Italy) and colleagues analyzed data from 50 studies including 54,323 children in total (0-18 years).

To be included, studies had to present prevalence figures on nasal colonization and be based on a child population only. Most of the studies were cross-sectional (n=40), although four were cohort studies and six were case-control studies.

The team estimated the prevalence of nasal colonization with MRSA as 2.7% in children with underlying medical conditions versus 2.3% in healthy children. Regarding location, 5.4% of hospitalized children had nasal colonization with MRSA versus 3.0% of children living in the community.

Risk factors for nasal colonization included prolonged hospitalization, having a family member or frequent contact employed in a healthcare facility, and previous hospitalization.

Notably, staphylococcal cassette chromosome (SCC)mec type IV was the most predominant type of MRSA observed on molecular genetic analysis, followed by SCCmec type II.

The researchers concede that nasal colonization with MRSA does not necessarily lead to infection, but say "nevertheless, our results show that the hospital remains the

environment where the microorganism circulates most."

They add: "We suggest that MRSA prevention strategies should be tailored to each specific institution, taking into account not only the nosocomial prevalence of MRSA nasal colonization and infections, but also the prevalence estimates of the community that refers to the health care center.

"Moreover, further research should focus on the opportunity of addressing specific MRSA prevention policies toward children affected with underlying medical conditions."

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