Molecular Characterization and Integron Gene Prevalence in Bacterial Pathogens from Neonatal Omphalitis
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Abstract
Neonatal umbilical cord infections (omphalitis) remain a significant cause of morbidity and mortality in developing countries. This study aimed to characterize bacterial pathogens associated with neonatal omphalitis using both phenotypic and molecular methods, and to determine the prevalence of integron genes. One hundred umbilical swabs were collected from neonates (3-28 days old) with clinical omphalitis. Bacterial identification was performed using conventional culture, the Vitek 2 Compact system, and 16S rRNA gene PCR sequencing. PCR detected integron genes (intI1, intI2, intI3). Phylogenetic analysis was conducted using MEGA X software. Bacterial growth occurred in 48/100 (48%) samples. The predominant isolates were Staphylococcus aureus (14/48, 29.16%), Escherichia coli (14/48, 29.16%), and Pseudomonas aeruginosa (14/48, 29.16%), followed by Enterococcus spp. (4/48, 8.33%) and Bacteroides spp. (2/48, 4.16%). All 24 tested isolates yielded 1500 bp 16S rRNA amplicons. Sequenced P. aeruginosa isolates showed 99-100% identity with GenBank references. Phylogenetic analysis revealed bootstrap values of 63-100% for P. aeruginosa, 99-100% for Enterococcus faecalis and Bacteroides sp., and 32-70% for E. coli. Integron gene prevalence varied significantly, with intI1 being the highest in E. coli (85.71%) and Enterococcus spp. (100%); intI2 predominated in P. aeruginosa (75%) and S. aureus (71.42%); intI3 was detected only in S. aureus (57.14%) and E. coli (28.57%). Gram-positive and Gram-negative bacteria equally contributed to neonatal omphalitis. High integron prevalence, particularly classes 1 and 2, indicates a significant potential for antimicrobial resistance, requiring enhanced surveillance and stewardship strategies.
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