ASSOCIATION OF INTEGRONS I, II AND III, VIRULENCE FACTORS AND FORMATION OF BIOFILM WITH MULTI DRUG RESISTANCE AMONG PSEUDOMONAS AERUGINOSA ISOLATED FROM CLINICAL AND HOSPITAL WASTEWATER IN BABYLON, IRAQ

Abstract

Objective: Pseudomonas aeruginosa is an opportunistic Gram-negative human pathogen that mostly affects immunocompromised individuals. Multidrug-resistant (MDR) P. aeruginosa is a common cause of nosocomial infection. The importance of P. aeruginosa is attributable to its diverse genes, virulence factors, pathways of metabolism and significant antibiotic resistance. This study is designed to compare P. aeruginosa isolates recovered from clinical/burn and non-clinical/hospital wastewater isolates to determine the existence of three integrons classes, antibiotic resistance genes, and biofilm-related genes.

Methods: Between March and November 2024, 85 samples were collected from various sources, including 66 (77.64 %) burn specimens and 19 (22.35%) hospital wastewater samples. Bacterial isolates were identified using microscopic, cultural, and biochemical criteria, as well as Vitek 2 System. Antibiotics resistance of bacterial isolates was tested against eight antibiotics and genotypically by detecting antibiotic resistance genes (blaNDM-1 and bla SHV). The polymerase chain reaction was used to identify three kinds of Integron genes. Biofilm formation was carried out utilizing both the microtiter plate method and genotypic methods, which involved the identification of biofilm genes (Bap, CsgA, and csgD genes).

Results: Out of eighty-five bacterial isolates were collected, only 29/85 (34.11%) classified as Pseudomonas aeruginosa of which 20 (30.30%) isolates were from clinical sources and 9 (47.36%) isolates from non-clinical sources. Additionally, 40/85 (47.05%) isolates were other bacteria. P. aeruginosa isolates from clinical sources showed varying levels of resistance to antimicrobial agents (85%, 17/20), whereas all P. aeruginosa isolates from hospital wastewater were antibiotic-sensitive, with the exception of 6 isolates (66.66%, 6/9) that was resistant to Ciprofloxacin whereas 3 isolates were resistant to Imipenem (33.33%, 3/9). All 9 isolates (100%) demonstrated non-MDR.  Biofilm generation were detected in 85% of clinical isolates, whereas 22.22% of non-clinical isolates were biofilm producers. All clinical isolates possessed the integrase 1 gene, as did 77.77% of nonclinical isolates. None contained int2 or int3. The ESBL gene, blaSHV, was found in one (5%, 1/20) clinical isolate but not in any nonclinical isolates. Carbapenemase gene was found in a high proportion of blaNDM -containing isolates 10 (50%, 10/20), whereas 3 (33.33%, 3/9) nonclinical isolates did contain the gene. The PCR findings showed that 90%, 75%, and 40% of the clinical isolates were positive for csgD, bap, and csgA respectively. P. aeruginosa isolates from non-clinical sources with these three genes were detected in 9 (100%), 5 (55.55%), and 3 (33.33%), of isolates respectively.

 Conclusion: P. aeruginosa with antibiotic resistances and several virulence genes could be commonly isolated from burns and hospital wastewater indicating their importance in public heath which requires immediate attention to burn treatment and prevention of contamination of burns with hospital wastewater. As a result, responsible organizations must focus their efforts on hospital wastewater treatment.