Detection of blaCTX-M15 and blaOXA-48 genes in Gram-negative isolates from neonatal sepsis in central of Iran

The aim of this study was to determine the prevalence of neonatal sepsis with a focus on antibiotic resistance and the frequency of the blaCTX-M-15 and blaOXA-48 genes in Gram-negative isolates.

A total of 108 Umbilical Cord Blood (UCB) and 153 peripheral blood samples were cultured via BACTEC from May 2017 to June 2018. The bacterial isolates were identified using phenotypic and genotypic analyses. The antibiotic susceptibility profile of the isolates was determined by disk diffusion. PCR was used to determine the frequency of β-lactamase genes.

Among the 153 infants, 21 (13.7%) proved positive for sepsis. Escherichia coli, Staphylococcus epidermidis and Klebsiella pneumoniae were the most frequent isolates in the peripheral blood cultures. E. coli and Stenotrophomonas maltophilia were isolated from two UCB cultures. The highest resistance among the Gram-positive strains was to cefixime, ceftriaxone, cefotaxime and clindamycin. In the Gram-negative bacteria the highest rates of resistance were to ampicillin (91.7%). The frequency of blaOXA-48 and blaCTX-M-15 genes was 25% and 50%, respectively.

The high antibiotic resistance among the isolates reveals the importance of monitoring antibiotic consumption and improving control standards in the health care system, especially in neonatal wards.