Prevalence of Class 1, 2 and 3 Integrons and Carbapenem-Resistance in Gram-Negative Bacteria

Abstract

Background: Resistance to various antimicrobial agents in gram-negative bacteria has become an important health threat with some acquired through integrons. Objectives: The present study aims to evaluate the resistance profiles, and the prevalance of integrases in gram-negative isolates. Methodology: We examined 70 gram negative isolates comprising 35 carbapenem-susceptible and 35 carbapenem-nonsusceptible isolates for antimicrobial resistance patterns against 13 antibiotics and the screening for integrases by polymerase chain reaction. Results: Isolates comprised 41 Enterobacteriaceae, 17 Pseudomonas aeruginosa, and 12 Acinetobacter baumannii. Pseudomonas aeruginosa was the most common detected among our isolates, followed by Escherichia coli and Acinetobacter baumanniii. Carbapenem-nonsusceptible gram-negative isolates showed significant higher rates of resistance to all tested antibiotics except for aztreonam. Class 1 were found among 12 and 29 isolates, while class 2 were detected in two and 9 isolates of carbapenem-susceptible and non-susceptible isolates, respectively with significant differences between both groups. None of the isolates expressed class 3 integrons. Class 1 integrons were mostly detected among Pseudomonas aeruginosa, Acinetobacter baumanniii, and Escherichia coli in both groups. Conclusion: Integrases were common among our gram-negative isolates. Their high prevalence denotes that the hospital environment may favor the formation of resistant gene cassettes that necessitate the application of effective measures to fight them.