Two outbreaks of mixed etiology associated with central venous catheters inserted by phlebotomy in critical neonates.

Staphylococcus aureus and coagulase-negative staphylococci are the main cause of sepsis in Neonatal Intensive Care Unit (NICU). Central venous catheters (CVCs) are an important part of critical neonates' treatment and are associated with sepsis. The aim of this study was to investigate two outbreaks caused by Staphylococcus aureus and Staphylococcus epidermidis associated with CVC inserted by phlebotomy in critical neonates. The surveillance was performed from January 2001 to December 2005 at the Brazilian NICU. The genotypic analysis of oxacillin susceptible S. aureus (OSSA) and oxacillin resistant S. epidermidis (ORSE) was performed based on pulsed-field gel electrophoresis (PFGE). Staphylococcus was the most frequent pathogen (65.8%) with highest incidence of CoNS (59.9%) followed by S. aureus (40.1%). During the five years of surveillance, there were two outbreaks detected, occurred in January-February/02 and August/02 and confirmed by PFGE analysis. The predisposing factors for infection corresponding to both outbreaks were: age < or =7 days, hospitalization > or =7 days, and use of polyethylene CVC through dissection of vein (phlebotomy). This is the first relate of staphylococcal outbreaks associated with CVC inserted by phlebotomy in NICU. PFGE showed polyclonal spread of OSSA during both epidemic and endemic period, and two monoclonal outbreaks of ORSE in the same epidemic period of OSSA.

Formação de biofilme em amostras de Staphylococcus epidermidis isoladas de sepse relacionada a cateter vascular central em neonatos críticos / Biofilm production in Staphylococcus epidermidis samples isolated fromsepsis associated with central vascular catheter (CVC) in critical neonates

Esta pesquisa teve como objetivo verificar a presença de biofilme em amostras de S. epidermidis isoladas de sangue em casos de sepse relacionados ao uso de CVC em neonatos críticos. O estudo foi realizado na Unidade de Terapia Intensiva Neonatal (UTIN) do Hospital de Clínicas da Universidade Federal de Uberlândia, no período de Jan/02 a Dez/06. Adicionalmente, foi realizado inquéritos de prevalência pontual de colonização por este microrganismo, através da coleta de espécimes da narina e axila com auxílio de swabs, entre Janeiro de 2004 e Junho de 2005. A avaliação de formação de biofilme foi realizada por densidade ótica em placas de poliestireno, após coloração com safranina, utilizando espectrofotômetro (570nm). O teste de suscetibilidadeà oxacilina foi realizado pelo método de diluição de acordo com o “Clinical and Laboratory Standards Institute”.Foram analisadas 109 amostras de S. epidermidis de episódios de sepse, sendo 83 (76,1%) relacionadas ao uso de CVC. Em relação à presença de biofilme, 67/83 (80,7%) das amostras isoladas de neonatos com sepserelacionadas a CVC, apresentaram produção intensa, enquanto que entre as 26 não relacionadas ao uso de CVC apenas seis (23,1%) demonstraram produção de biofilme, assim como, 10 (12,3%) entre as associadas à colonização. Cerca de 73% das amostras foram resistentes à oxacilina (concentração inibitória mínima ³0,5mg/ml), incluindo 56 (83,6%) correspondentes a casos de infecção relacionados à CVC, seis (100%) amostras não relacionadas ao uso de CVC e em quatro (40%) de amostras de colonização. Conclui-se que a maioria das amostras de S. epidermidis isoladas de sepse relacionadas à CVC foram biofilme positivas e resistente à oxacilina

This research aimed to observe the biofilm production by Staphylococcus epidermidis isolated associated with central vascular catheter (CVC) related bacteremia in critical neonates. The study it was carried out in Neonatal Intensive Care Unit of the Hospital das Clínicas da Universidade Federal de Uberlândia, in the period of Jan/02 to Dez/06. Additionally, it was carried out inquiries of prevalence, through the specimen collection of the nostril and armpit with aid of swabs, between Jan/04 and Jun/05. The evaluation of biofilm production was by optical density in polystyrene plates, stained with safranin and measured with ELISA reader at 570nm. The oxacilin susceptibility test was carried out through to the dilution method in accordance with the “Clinical and Laboratory Standards Institute”. It was analyzed 109 S. epidermidis samples, being 83(76.1%) related to the use of CVC. In relation to the biofilm presence, 80.7% of the neonates isolated samples with sepsis related the CVC, had presented intense production, whereas of the 26 unrelated ones to the useof CVC, only six (23.1%) had demonstrated biofilm production as well as 10 (12.3%) of the samples associated to the colonization. About 73% of the samples were oxacilin resistant (minimum inhibitory concentration³0.5mg/ml) . In conclusion, the S. epidermidis samples isolated of CVC related sepsis were biofilm positive and pertaining to oxacilin resistant phenotype