Clinical and Molecular Epidemiology of Methicillin-Resistant Staphylococcus aureus in a Neonatal Intensive Care Unit in the Decade following Implementation of an Active Detection and Isolation Program

Abstract

1, 2). The National Nosocomial Infections Surveillance System observed a Ͼ300% increase in the incidence of late-onset MRSA infections in NICUs, from 0.7 to 3.1 infections/10,000 patient days, between 1995 and 2004 (3). Unique host and environmental factors, including immature immune systems, high frequency of contact with health care providers (4), exposure to numerous invasive procedures, NICU overcrowding and understaffing (5, 6), and prolonged hospitalization (7), make NICU patients at especially high risk of becoming colonized and infected with MRSA. Since colonization with MRSA is a risk factor for development of MRSA infection, prevention of MRSA transmission within the NICU is critical (7,8). Many NICUs have implemented active detection and isolation (ADI) programs, which involve surveillance to rapidly identify affected patients, followed by cohorting and isolation with standard contact precautions, in attempts to prevent MRSA transmission and reduce infection rates.Several large NICUs have published reports regarding the clinical epidemiology of neonatal MRSA following implementation of surveillance, transmission prevention, and/or decolonization strategies (7,(9)(10)(11)(12). Some also incorporated molecular analyses in their studies, including antibiotic susceptibility testing (9, 10), strain typing (9, 11, 12), genotyping (9, 12), and/or Panton-Valentine leukocidin gene detection (9,12). No studies have comprehensively examined all of those molecular features of MRSA and additionally assessed the presence or absence of genes encoding proteins for a variety of staphylococcal toxins and potential virulence factors over an extensive time period following implementation of an ADI program in an NICU.In response to the appearance of MRSA in the NICU at YaleNew Haven Children's Hospital (YNHCH)

Emergence of community-associated methicillin-resistant Staphylococcus aureus strains in the neonatal intensive care unit: an infection prevention and patient safety challenge

“…Notwithstanding an active surveillance and isolation program and standardized decolonization protocol, nearly 4% of the infants in our NICU were colonized with MRSA over the study period, consistent with previous NICU studies in the U.S. [9, 25]. Within our study cohort, the predominant colonizing strains were CA-MRSA, and infants colonized with these CA-MRSA strains developed infections more quickly than infants colonized with traditional HA-MRSA strains.…”

“…This risk, as well as the potential for colonized neonates to serve as reservoirs for transmission to other vulnerable patients within the NICU, has prompted a focus on infection prevention measures to decrease MRSA colonization rates [9, 13, 14]. While cohorting, isolation, and contact precautions are effective in reducing MRSA prevalence rates [25], many U.S. centers, upon identifying an MRSA colonized patient, employ topical antimicrobials in an effort to eradicate MRSA carriage and thereby prevent MRSA transmission and infection [27, 28]. Among adult patients, the practice of universal chlorhexidine bathing has yielded success in reducing the incidence of MRSA infection in ICUs compared to surveillance and isolation alone [29].…”

Staphylococcus Infections in Pregnancy

“…14 Both methicillin-sensitive S. aureus (MSSA) and MRSA are associated with chorioamnionitis and neonatal sepsis, lactational mastitis, breast abscess, perineal abscess, and infections associated with laceration/episiotomy as well as surgical site infection after cesarean birth. [14][15][16][17][18][19][20][21][22][23][24][25] The bacterium is also commonly seen during pregnancy as an SSTI.…”

Decolonization of Methicillin resistantStaphylococcus aureus: Role in the Neonatal Intensive Care Unit

“…Procedures and devices such as endotracheal intubation and mechanical ventilation 6,16,24,26) , percutaneous central venous catheterization 16) , and parenteral feedings 16) are also known to be risk factors for MRSA infection. In a recent study, outborn infants were also described as a risk factor for MRSA colonization 5) .…”

“…In a recent meta-analysis, the prevalence of MRSA colonization upon admission was 1.5% (95% confidence interval [CI] 0.9-2.2) among NICU patients 5) . Several factors contribute to NICU patients being at a particularly high risk of being colo nized and infected with MRSA, including an immature immu ne system, exposure to numerous invasive procedures 6) , prolonged hospitalization 7) , and, especially, a high frequency of contact with health care providers 8,9) . It has been reported that MRSA colonization or infection is associated with mortality in the NICU 10) .…”