Evaluation of toxin-antitoxin genes, antibiotic resistance, and virulence genes in Pseudomonas aeruginosa isolates

Abstract

OBJECTIVE: Toxin-antitoxin genes RelBE and HigBA are known to be involved in the formation of biofilm, which is an important virulence factor for Pseudomonas aeruginosa. The purpose of this study was to determine the presence of toxin-antitoxin genes and exoenzyme S and exotoxin A virulence genes in P. aeruginosa isolates and whether there is a relationship between toxin-antitoxin genes and virulence genes as well as antibiotic resistance. METHODS: Identification of the isolates and antibiotic susceptibilities was determined by a VITEK 2 (bioMérieux, France) automated system. The presence of toxin-antitoxin genes, virulence genes, and transcription levels were detected by real-time polymerase chain reaction. RESULTS: RelBE and HigBA genes were detected in 94.3% (82/87) of P. aeruginosa isolates, and exoenzyme S and exotoxin A genes were detected in all of the isolates (n=87). All of the isolates that harbor the toxin-antitoxin and virulence genes were transcribed. There was a significant increase in the RelBE gene transcription level in imipenem-and meropenem-sensitive isolates and in the HigBA gene transcription level in amikacin-sensitive isolates (p<0.05). There was a significant correlation between RelBE and exoenzyme S (p=0.001). CONCLUSION: The findings suggest that antibiotic resistance may be linked to toxin-antitoxin genes. Furthermore, the relationship between RelBE and exoenzyme S indicates that toxin-antitoxin genes in P. aeruginosa isolates are not only related to antibiotic resistance but also play an influential role in bacterial virulence. Larger collections of comprehensive studies on this subject are required. These studies should contribute significantly to the solution of the antibiotic resistance problem.

Evaluating the antibacterial effect of meropenem-loaded chitosan/sodium tripolyphosphate (TPP) nanoparticles on Acinetobacter baumannii isolated from hospitalized patients

“…For instance, Coskun and colleagues reported that Pseudomonas aeruginosa and Staphylococcus isolates sensitive to gentamicin, ciprofloxacin, levofloxacin, clindamycin, phosphomycine, nitrofurantoin, fusidic acid, cefoxitin expressed relatively higher levels of the mazEF gene compared with those of the resistant isolates [ 11 ]. Based on the findings of a more recent report by Coşkun and colleagues, P. aeruginosa isolates sensitive to imipenem and meropenem expressed significantly higher levels of the relBE gene while isolates sensitive to amikacin significantly expressed higher levels of the higBA gene [ 13 ]. Regarding A. baumannii , Ghafourian and colleagues reported that the mazEF gene was expressed by 85 clinical isolates and that this TA system-related expression should be further investigated as an antibacterial therapeutic strategy [ 7 ].…”

“…These systems belong to the type II TA systems. Among the TA systems found in A. baumannii, three genes, namely mazEF, relBE, and higBA, are the most investigated and important ones that belong to the type II TA system [5,7,[11][12][13][14]. Previous investigations have studied the relationship between these genes and antibiotic resistance and have asserted that further investigations are necessary.…”