Comparative Analysis of Culture-Based Salivary Microbiota in Children with Down Syndrome and Healthy Children in Benghazi, Libya

• Nadine Ali Kamal

  MSc in Microbiology, Libyan Academy for Postgraduate Studies, Benghazi, Libya

  Author

• Salha Ben Jweirif

  Department of Microbiology, University of Benghazi, Benghazi, Libya

  Author

Background: Children with Down syndrome (DS) are at increased risk of oral diseases due to altered immune function, anatomical characteristics, and changes in the oral microbial ecosystem and cultivable salivary microbiota. However, data on the salivary microbiota of Libyan children with Down syndrome remain scarce. Objective: This study aimed to compare the cultivable salivary microbiota of children with Down syndrome and healthy controls in Benghazi, Libya, and to assess the antimicrobial susceptibility patterns of the isolated microorganisms. Methods: A comparative cross-sectional study was conducted among 100 children aged 5-14 years, including 46 children with Down syndrome and 54 healthy controls. Unstimulated saliva samples were collected under aseptic conditions and cultured using standard microbiological techniques. Bacterial and yeast isolates were identified by colony morphology, Gram staining, biochemical tests, and an automated identification system when required. Antimicrobial susceptibility testing was performed using the Kirby-Bauer disk diffusion method according to CLSI guidelines. Data were analyzed using SPSS, with statistical significance set at P < 0.05. Results: A total of 110 microbial isolates were recovered from the 100 saliva samples. Gram-positive bacteria constituted 53.6% of the isolates, followed by Gram-negative bacteria (24.6%) and yeasts (21.8%). Staphylococcus aureus and Staphylococcus epidermidis were the most frequently isolated Gram-positive bacteria, while Klebsiella spp. was the predominant Gram-negative isolate. Candida spp. was isolated more frequently from children with Down syndrome. Antimicrobial susceptibility testing showed high susceptibility to vancomycin among Gram-positive isolates and to imipenem among Gram-negative isolates, whereas resistance to amoxicillin, penicillin, erythromycin, and cefotaxime was commonly observed. Conclusion: Children with Down syndrome exhibited a distinct cultivable salivary microbiota characterized by increased colonization with opportunistic microorganisms. These findings provide baseline data on the cultivable salivary microbiota of Libyan children with Down syndrome and may contribute to improving preventive oral healthcare strategies and guiding future microbiological research.

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