High rate of neonates colonized by methicillin-resistant Staphylococcus species in an Intensive Care Unit

Abstract

Introduction: Staphylococcal colonization is a risk factor for healthcare-associated infections, which are frequent in Neonatal Intensive Care Units (NICU). This study analyzed microbiology, epidemiology and clinical aspects of Staphylococcus spp. colonizing neonates.
 Methodology: Nasal or periumbilical swabs were evaluated from 175 newborns admitted to a NICU of a Rio de Janeiro hospital from March to September 2009. Clinical data were obtained from the medical records. SCCmec typing and the mecA and Panton-Valentine Leukocidin (PVL) genes were detected by PCR. Clonal diversity was evaluated by pulsed-field gel electrophoresis.
 Results: Staphylococcus spp. isolates were detected in 98 (56%) neonates, 66.3% of them had birth weight ≤ 2500 g, 62.2% were preterm (˂ 37 weeks) and the mean length of hospitalization was 14.9 days. Among the 133 isolates identified, 48.1% were S. epidermidis, 23.3% S. haemolyticus and 13.5% S. aureus. Methicillin-resistant Staphylococcus isolate was detected in 77.6% of neonates. The methicillin-resistant S. aureus isolates carried the SCCmec type IV, while 94.6% of S. epidermidis and 85.7% of S. haemolyticus presented non-typeable cassettes. Among the S. aureus, 55.6% had PVL genes and the USA800 genotype was prevalent. Two genotypes of S. epidermidis and one of S. haemolyticus clustered 42.2% and 25.8% of the isolates, respectively. S haemolyticus colonization was associated with the use of parenteral nutrition and mechanical ventilation.
 Conclusion: High rate of neonates colonized by methicillin-resistant Staphylococcus species and the permanence of clones circulating in the NICU highlight the importance for continuous and preventive surveillance in this high-risk population.

Pandemic clone USA300 in a Brazilian hospital: detection of an emergent lineage among methicillin-resistant Staphylococcus aureus isolates from bloodstream infections

“…The SCCmec typing [18] and subtyping [19] for isolates resistant to oxacillin by the disk-diffusion method were assessed by multiplex polymerase chain reaction (PCR), using bacterial DNA obtained using the QIAamp DNA Mini Kit (QIAGEN, Hilden, Germany). The Staphylococcus strains used as positive controls are described in Salgueiro et al [20].…”

Inanimate Surfaces and Air Contamination with Multidrug Resistant Species of Staphylococcus in the Neonatal Intensive Care Unit Environment

“…During hospitalization, patients spread bacteria capable of surviving for long periods on inanimate surfaces and in the air, including Gram-positive bacteria, which are one of the main etiological agents of HAI in the NICU [ 3 , 7 ]. Coagulase-negative Staphylococcus (CoNS) are responsible for up to 40% of these infections, with emphasis on Staphylococcus epidermidis and Staphylococcus haemolyticus , while Staphylococcus aureus is responsible for up to 25% of HAIs [ 8 , 9 , 10 , 11 , 12 , 13 , 14 ].…”

Influence of Sub-Inhibitory Dosage of Cefotaxime on Multidrug Resistant Staphylococcus haemolyticus Isolated from Sick Neonatal Care Unit

“…Coagulase-negative staphylococci (CoNS) are currently one of the major causes of device-related infections by forming biofilms, particularly in immunocompromised patients [1,2] and the methicillin-resistant species are known to be dominant colonizers among neonates admitted to intensive care units [3]. Among the CoNS species, S. haemolyticus is the leading cause of late-onset sepsis (LOS) in neonates and also plays a very important role in hospital-acquired infections worldwide [4,5].…”