Evaluation of Gram-Negative Bacterial Infections Producing Extended Spectrum Beta-Lactamase in Preterm and Term Infants in a Neonatal Intensive Care Unit

Introduction:The aim of this study was to determine the distribution of extended spectrum beta-lactamase (ESBL) positive strains, antibiotic resistance rates and risk factors contributing to ESBL production.Methods:The study included 75 preterm (28-36 weeks) and term (37-42 weeks) newborns, monitored for at least two days in our hospital neonatal intensive care unit, and had ESBL-positive microorganisms in various clinical cultures. Demographic features and clinical information obtained from the patient records were evaluated retrospectively. Species identification and antibiogram susceptibility tests for isolated ESBL-positive bacteria were performed using conventional methods and BD Phoenix System (Beckton Dickinson, USA). Combination disc test was used to detect ESBL positivity.Results:A total of 115 ESBL-positive strains were isolated from 75 preterm and term infants monitored in the neonatal intensive care unit. These strains were K. pneumoniae (n=68, 59.1%), E. coli (n=42, 36.5%) and K. oxytoca (n=5, 4.3%). The most common infections were; urinary tract infection (n=41, 35.7%), pneumonia (n=34, 29.6%) and bacteremia (n=30, 26.1%). Following birth, the majority of culture positives (n=107/115, 93.0%) were seen 7 days after birth. Of the 75 neonates included in the study, 64% (n=48/75) were hospitalized for more than 30 days. While all of these isolates were resistant to antibiotics except amoxicillin-clavulanate, ampicillin, ampicillin-sulbactam, piperacillin and a K. oxytoca strain, all strains were susceptible to the carbapenem group antibiotics (imipenem, ertapenem).Conclusion:Antibiotic resistance has been increasing in ESBL-positive strains in preterm and term infants in neonatal intensive care units. Detection of ESBL-positive bacteria distribution, antibiotic resistance rates and infection risks as well as selection of antimicrobial treatments according to antibiogram results may increase treatment success, and prevent ESBL production and resistance development.