DOI: 10.1097/INF.0000000000000172
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Issn Print: 0891-3668
Publication Date: 2014/03/01
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Excerpt
Methicillin-resistant Staphylococcus aureus (MRSA) is an important cause of infections in healthcare and community settings, and its epidemiology has been changing rapidly. Recent studies, predominantly in adult populations, have revealed reductions in both healthcare-associated and community-onset (CA) invasive MRSA infections. Meanwhile, the epidemiology of infections among children is less established and likely distinct from that in adults. Prevention of MRSA infections both in healthcare and community settings remains a priority. Identifying the unique epidemiologic characteristics, burden and trends in incidence of MRSA infections in children is needed to develop strategies to further decrease risks of infection. The results of laboratory- and population-based surveillance for invasive MRSA infections in children during 2005–2010 are described.
Cases were defined as isolation of MRSA from a normally sterile site and classified on the basis of the setting of the positive culture and presence or absence of healthcare exposures. Among young infants, cases were categorized as early-onset infection if MRSA was isolated from infants <3 days or late-onset infection if infants were 3–89 days of age. Estimated annual changes in incidence were determined using regression models. National age- and race-specific incidences for 2010 were estimated by using US census data.
During 2005 through 2010, 876 cases of invasive MRSA infections were reported among 834 pediatric patients. The median age at time of infection was 2.1 years (range, 0 days to l1 years), and 39% of cases occurred among infants <1 year. Most (799 of 876; 91%) were hospitalized, and there were 53 (6%) fatal cases. Males accounted for 59% (490 of 834) patients. Among patients with reported race, 59% were black, 36% were white and 5% were children of other races. Overall, 68% (565 of 834) of children with invasive MRSA infection had an underlying medical condition, including prematurity (19%), dermatologic condition (eg, eczema, abscesses) 18%, asthma (8%), congenital disorder (4%), renal disease (2%) and malignancy (2%).
Of the 876 cases, 857 were classified into an epidemiologic category: 363 (42%) were CA (culture was obtained in an outpatient setting or before the fourth calendar day of hospitalization in a patient without documentation of a healthcare risk factor) MRSA infections, 298 (35%) were hospital-onset (HO; culture was obtained on or after the fourth calendar day of hospitalization) MRSA infections and 196 (23%) were healthcare-associated community-onset (HACO; culture was obtained in an outpatient setting or before the fourth calendar day of hospitalization in a patient with an established healthcare risk factor.
The most common healthcare risk factors among cases with HO- and HACO-MRSA infections were previous hospitalizations (35% and 86%, respectively) presence of a central venous catheter (32% and 28%, respectively), and history of surgery (22% and 26%, respectively). More than 80% of HO- and HACO-MRSA cases were in patients with a reported underlying condition, compared with half of CA-MRSA cases. The proportion of CA-MRSA infections was highest in children 5–10 years of age (92 of 130, 71%).
MRSA was isolated from blood in 692 cases (79%) and 364 cases (41.6%) were blood stream infections only without another infection syndrome. However, of these 364 cases, 248 (68%) had a central venous catheter within the 2 days before the positive MRSA blood culture. Other common types of invasive infections included bone and joint infections (179 of 876; 20%), skin and soft tissue infections (152 of 876; 17%), pneumonia or empyema (129 of 876; 15%) and meningitis or cerebrospinal fluid shunt infection (35 of 876; 4%).
Overall, the predominant strain patterns were USA300 (184 cases; 72%) and USA100 (47 cases; 18%); other pulsed-field types were less common, each accounting for <2% of isolates.
