Detection of qacE and qacEΔ1 genes in acinetobacter baumannii and pseudomonas aeruginosa isolated from hospital environments

Abstract

Objective: To determine the prevalence of qacE and qacEΔ1 genes among Acinetobacter baumannii and Pseudomonas aeruginosa obtained from hospital environments, and assess their potential role in disinfectant resistance within healthcare settings. Methods: The bacterial isolates were obtained from different hospital surfaces and medical equipment, from medical city hospitals in Baghdad (Baghdad Teaching Hospital, Children Welfare Teaching Hospital, Ghazi Al-Hariri Hospital for surgical specialties, and teaching laboratories in Medical City).  The disc diffusion method was used to determine the susceptibility of A. baumannii and P. aeruginosa strains to three different disinfectants. DNA was extracted from bacteria and conventional polymerase chain reaction (PCR) techniques were used for each DNA extracted sample in order to detect the presence of qacE and qacEΔ1 and determine the prevalence of each gene among more resistant isolates. Result: The 24 A. baumannii and P. aeruginosa disinfectant-resistant isolates were molecularly analyzed using conventional PCR techniques. The qacE gene was present in 76.92% of Acinetobacter baumannii and 100% in Pseudomonas aeruginosa before disinfectant treatment, and decreased to 53.85% and 61.5% respectively after treatment. The qacEΔ1 gene was detected in 15.3% of A. baumannii and 53.8% of P. aeruginosa isolates prior the treatment, but was completely absent in all isolates after disinfectant exposure. Conclusion: The study demonstrated that the prevalence of the QacE gene in A. baumannii and P. aeruginosa decreased after disinfectant treatment, while the qacEΔ1 was completely lost. These findings emphasize the need to improve hospital disinfection strategies by optimizing disinfectant combinations and concentrations to target biofilm-forming bacteria. Routine monitoring of resistance genes such as qacE and qacEΔ1 should be included in infection control programs. This suggests disinfectants can partially suppress resistance genes but fail to fully eliminate resistant strains, especially those with strong biofilm-forming ability.