Type VI secretion system (T6SS) in Klebsiella pneumoniae, relation to antibiotic resistance and biofilm formation

Nesma A Mohamed; Mohamed H Alrawy; Reem M. Makbol; Arafat M Mohamed; Shimaa B Hemdan; Noha S Shafik

doi:10.18502/ijm.v15i5.13865

Nesma A Mohamed Department of Medical Microbiology and Immunology, Faculty of Medicine, Sohag University, Sohag, Egypt
Mohamed H Alrawy Department of Clinical and Chemical Pathology, Faculty of Medicine, Sohag University, Sohag, Egypt
Reem M. Makbol Department of Tropical Medicine & Gastroenterology, Faculty of Medicine, Sohag University, Sohag, Egypt
Arafat M Mohamed Department of Otorhinolaryngology, Sohag University, Sohag, Egypt
Shimaa B Hemdan Department of Medical Biochemistry, Sohag University, Sohag, Egypt
Noha S Shafik Department of Medical Microbiology and Immunology, Faculty of Medicine, Sohag University, Sohag, Egypt

DOI: https://doi.org/10.18502/ijm.v15i5.13865

Keywords: Type VI secretion system; Biofilm; Antibiotic resistance; Klebsiella pneumoniae

Abstract

Background and Objectives: The type VI secretion system (T6SS) was identified as a novel virulence factor in many Gram-negative bacteria. This study aimed to investigate the frequency of the T6SS genes in Klebsiella pneumoniae-causing different nosocomial infections, and to study the association between T6SS, antibiotic resistance, and biofilm formation in the isolated bacteria.

Materials and Methods: A total of fifty-six non-repetitive K. pneumoniae isolates were collected from different inpatients admitted at Sohag University Hospital from September 2022 to March 2023. Samples were cultured, colonies were identi- fied, and antimicrobial sensitivity was done by VITEK® 2 Compact. Biofilm formation was checked using Congo red agar method. T6SS genes, and capsular serotypes were detected by PCR.

Results: Fifty-six K. pneumoniae isolates were obtained in culture. 38 isolates (67.86%) produced biofilm and 44 (78.57%) were positive for T6SS in PCR. There was a significant association between the presence of T6SS and resistance to the following antibiotics: meropenem, ciprofloxacin, and levofloxacin. All biofilm-forming bacteria had T6SS, with significant differences towards T6SS -positive bacteria. There was no significant association between T6SS, and the presence of certain capsular types.

Conclusion: The T6SS-positive K. pneumoniae has greater antibiotic resistance, and biofilm-forming ability which is con- sidered a potential pathogenicity of this emerging gene cluster.