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The association between mucosal colonisation with opportunistic pathogens and bloodstream infections in the two neonatal intensive care units in Estonia

Abstract number: P1090

Parm Ü., Sepp E., Metsavaht T., Ilmoja M., Pruunsild K., Maipuu L., Kõljalg S., Makoid E., Lutsar I.

Objective We aimed to study mucosal colonisation of neonates with potentially pathogenic microorganisms in order to find out whether and how this is associated with blood stream infections (BSI).

Methods All newborns admitted to both Estonian NICUs within first 72 h of life and needing empiric antibacterial therapy (ampicillin or penicillin in combination with gentamicin) for early onset neonatal sepsis were prospectively enrolled. The nasopharyngeal and rectal swabs were collected on admission and thereafter twice weekly until D60 or discharge. Samples were plated on blood, McConkey and Saboraud agar. Blood cultures were drawn when clinically indicated. The final identification of species was conducted with BACTEC 9240, VITEK 2 and API 20E systems. MRSA was identified by PCR for nuc and mecA genes. The genetic relatedness between mucosal and bacteraemic strains of MRSA and K. pneumoniae was analysed by pulsed fieled gel electrophoresis (PFGE).

Results A total of 200 pt (100 with BW <1500g; median NICU stay 6.8 days) were enrolled from Aug 2006 until July 2007. The most common colonising Gram-negative microorganisms were K. pneumoniae (23%), E. coli (15%), E.cloaceae (15%), K. oxytoca (14%) & A. baumannii (13%) with the median documented duration of colonisation of 8 days for Klebsiella spp. and 5 days for the remaining organisms. Of 54 BSI infections 45 were nosocomial origin (58% caused by G-positive, 40% by G-negative and 2% by Candida spp.). The risk of BSI was greater during colonisation by G-negative than by G-positive bacteria (15/21 vs 13/31, respectively [OR 3.5; 95% CI 1.1–11.3]). The rate of infection per 100 days of colonisation was the highest for MRSA (4.6) followed by 1.4; 1.2; 0.9; 0.7; & 0.7 for A. baumannii, E. cloacae, E. coli, K. pneumoniae & Serratia spp., respectively. The lowest rate of 0.2 was observed for K. oxytoca. During the study in each unit one outbreak of nosocomial infections caused by K.pneumonia and MRSA, respectively, was seen. Increased rate of mucosal colonisation preceded both outbreaks. A molecular typing of mucosal and BSI isolates of K. pneumoniae and MRSA revealed a similar PFGE pattern.

Conclusion In NICU mucosal colonisation by MRSA and to lesser extent by A. baumannii and E.cloaceae carries a significant risk for BSI. Isolation of newborns colonised by microbes with the highest risk of subsequent BSI, should be implemented to avoid cross-colonisation by healthcare workers and thus prevent BSI.

Session Details

Date: 19/04/2008
Time: 00:00-00:00
Session name: 18th European Congress of Clinical Microbiology and Infectious Diseases
Subject:
Location: Barcelona, Spain
Presentation type:
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