Relationship between the Presence of the nalC Mutation and Multidrug Resistance inPseudomonas aeruginosa

Objectives. The current study was conducted to determine the relationship between the presences of significant multidrug resistance inPseudomonas aeruginosa(P. aeruginosa) having intactmexRgenes (nalC) to different antibiotics.Methods. In order to identify nalC, fifty strains ofP. aeruginosawere obtained. All isolates were found in urinary tract infections. They were evaluated against different antibiotics. The nalC mutant was identified by PCR.Results. The 50 clinical isolates ofP. aeruginosaoriginated from two hospitals in Iran, in which 32 isolates were found in Milad hospital, and 18 isolates were collected in the Ilam Hospital. The results in Milad hospital of nalC revealed that allP. aeruginosaresistant to oxacillin showed the presence of nalC. In Ilam hospital only three (16.6%) isolates were resistant to oxacilin and aztreonam, and among these three isolates only one isolate revealed resistance to ceftazidime and amikacin. The resistant isolates showed the presence of both OXA-10 and nalC.Conclusion. Our results showed that the presence of nalC was observed amongP. aeruginosaresistance to oxacilin. Thus, the finding suggested relationship between oxacilin resistance and presence of nalC and consequently overproduction of the MexABOprM efflux system.