Clinical and Molecular-Biologic Study of Extended Spectrum beta-lactamase Producing Klebsiella pneumoniae in a Neonatal Intensive Care Unit

ABSTRACT

PURPOSE: Extended spectrum beta-lactamase (ESBLs) producing Klebsiella pneumoniae has recently been increasingly responsible for infections. Considering the characteristics of the neonatal intensive care unit (NICU), the increase in such colonies is to be an important factor in the treatment and outcome of neonatal patients. Therefore, we performed this study in order to investigate the incidence of this colony and the clinical characteristics that are helpful in diagnosing these infections. METHODS: We performed a double disk synergy test and randomly amplified polymorphic DNA (RAPD) analysis of which 12 was resistant or intermediate to cefotaxime, and 4 colonies isolated from rectal swab taken in 14 patients between July and August, 1997. Also, we compared the annual isolation rate of K. pneumoniae, from those admitted to the Soonchunhyang University Chunan Hospital NICU from July, 1997 to June, 2000. We retrospectively studied the medical records and the clinical characteristics of those 79 cases from whom 110 colonies were isolated. RESULTS: From July to August, 1997, there was a K. pneumoniae outbreak in the NICU. Fifteen out of a total of sixteen isolates were positive in the double disk synergy test and turned out to be ESBL producing K. pneumoniae. Also the RAPD analysis of thirteen isolates which were from the NICU proved eleven isolates to have similar band pattern on RAPD typing. In those who were admitted to our NICU from July, 1997 to June, 2000, 110 colonies of K. pneumoniae resistant or intermediate to cefotaxime were isolated from 79 patients. Though patient group infected by the ESBLs producing K. pneumoniae had significantly no difference in gestational age or birth weight, they had a longer hospitalization period compared to the control group. CONCLUSION: It is possible that ESBLs producing K. pneumoniae be responsible for outbreaks in the NICU. The emerging of these can affect the morbidity in neonates and also can put great limits in the choice of antibiotics.