Text Box: CHANGES OF BACTERIA DETECTED FROM BLOOD CULTURE OF PEDIATRIC PATIENTS IN 17 YEARS AND ANALYSES OF ANTIMICROBIAL RESISTANCE
Guo Y-F, Zhen J-H, Zhang M-H and Dong F
Beijing Children’s Hospital, China

Objective: To investigate the changes of bacteria detected from blood culture of pediatric patients in the past 17 years and the relations between the isolated bacterial species and age of the patients and season, and to observe the antimicrobial resistance of these bacteria.
Methods: Totally 6569 bacterial isolates were obtained from blood culture between 1983 and 1999. Glucose broth and API system were applied for culture and differentiation before 1997 and later on BD blood culture apparatus was used for culture, whereas API and microscan for differentiation and antimicrobial resistance determination. Results were interpreted according to NCCLS recommendations.
Results: Coagulase negative staphylococci (CNS) accounted for more than 50% every year. Enterococcus increased from 4.8% in early 1990’s to 15.9% in 1999 (Enterococcus faecium accounted for 68.8%). Klebsiella increased from 0.4% of to 3.1%. Enterobacter increased from 0.1% to 1.4%. Escherichia coli and Staphylococcus aureus decreased from 8.1% and 6.3% in to 2.1% and 1.6% respectively. Salmonella decreased from 2.7% to 0.2%. Methicillin resistant Staphylococcus aureus and methicillin resistant coagulase negative Staphylococci accounted for 16% and 64%, respectively. The antimicrobial resistance of Enterococcus faecalis to ampicillin, penicillin and vancomycin was 18%, 33% and 10%, whereas resistance of Enterococcus faecium was 83%, 86% and 4%. High level aminoglycosides resistant Enterococcus faecalis and faecium accounted for 40% and 60%. The antimicrobial resistance of Enterobacteriaceae to imipenem, ceftazidime and amikacin was all below 50%. Escherichia coli and Klebsiella produced the extended spectrum b-lactamase (ESBL) were accounted for 60% and 86%.  
Conclusions: (1) Low virulence conditional bacteria became common in pediatric patients. (2) Gram-positive bacteria, CNS, Enterococcus faecium and complex bacteria were more frequently detected among 1-5 months old baby than other groups. (3) Detection rate of some bacteria and the level of antimicrobial resistance in children were higher than those in adults. Medication should follow the result of surveillance of antimicrobial resistance.

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