Community-associated (CA) strain of MRSA have been increasingly reported worldwide. Hospitalized neonates are recurrent victims of these pathogens outbreaks, and the facts about sources of, diffusion, and controlling these outbreaks are not well evident. This report is describing the first outbreak of CA-MRSA infection, among neonates in a well-baby nursery in a teaching hospital. It demonstrates the investigation procedures, control measures that had been followed, possible risk factors and outcomes of infected cases. This report is expected to highlight the rate of this pathogen and contribute in developing effective measures to deal with and help prevention of these outbreaks, whether locally or globally.
Methodology
It was a case-control study, among neonates who were born in on labor and delivery ward, and admitted to the concerned well baby nursery in a teaching hospital in Riyadh, Saudi Arabia, at any time between 19th Oct and 11th Nov 2008. Case defined as a neonate admitted to nursery A, presented with skin manifestation and found positive for MRSA, upon admission or within 30 days after discharge. Control (4 to each case) was selected from asymptomatic neonates admitted to the same nursery and matched for the day of admission.
Results
15 cases found CA-MRSA positive, 13 neonates and two mothers. Crude attack rate among neonates during outbreak period was 5.5%. All the 13 neonates presented with skin pustules and one of the mothers had mastitis and abscess, while the other was asymptomatic. The mean gestational age among cases was (Mean ± S.D) (38.15 ± 1.63) vs. (39.06 ± 1.19) among controls (P-value = 0.02). The mean birth weight (kg) among cases and controls were (2.99 ± 0.51) and (3.29 ± 0.44) consecutively (P-value = 0.04). The mean hospital stay among cases was (3.8 ± 1.4, 95% CI 2.9 - 4.6) vs. (3.2 ± 1.6, 95% CI 2.8 - 3.7) among controls (P-value = 0.2). All screening swabs were negative. PFGE showed all tested isolates from one strain except one.
Conclusion
The source of the outbreak and mechanism of transmission were not evident, as no cultures of staff members or the environment yielded this particular strain of MRSA. The clinical presentation of the cases were mild to moderate, self-limited in some and good response to treatment in others, with no invasive complications. Not much difference had been noticed neither between cases and controls, nor their mothers. Outbreak investigation required some modification to allow finding the source. Infection control measures were good as the outbreak was contained smoothly, but some measures were not evident based.