Infection and Drug Resistance (Aug 2020)
Prevalence and Molecular Typing of Colistin-Resistant Pseudomonas aeruginosa (CRPA) Among β-Lactamase-Producing Isolates: A Study Based on High-Resolution Melting Curve Analysis Method
Abstract
Hamed Tahmasebi,1 Sanaz Dehbashi,2 Mohammad Reza Arabestani2,3 1Microbiology Department, Faculty of Medicine, Zahedan University of Medical Sciences, Zahedan, Iran; 2Microbiology Department, Faculty of Medicine, Hamadan University of Medical Sciences, Hamadan, Iran; 3Nutrition Health Research Center, Hamadan University of Medical Sciences, Hamadan, IranCorrespondence: Mohammad Reza ArabestaniMicrobiology Department, Faculty of Medicine, Hamadan University of Medical Sciences, Pajoohesh Junction, Hamadan, IranTel +98-918-866-2009Email [email protected]: The frequency and production of β-lactamase enzymes may be different in colistin-resistant Pseudomonas aeruginosa (CRPA) strains compared to susceptible strains. The purpose of this study was to investigate the relationship between colistin resistance and β-lactamase enzymes in different Sequence Types (ST) of P. aeruginosa.Methods: A total of 101 P. aeruginosa isolates were collected from different samples. The antimicrobial susceptibilities of the bacterial isolates were examined by disk diffusion and MIC E-test methods. Also, real-time PCR and high-resolution melting curve analysis (HRMA) assay were performed to detect the resistance genes.Results: Out of the 101 P. aeruginosa isolates, four isolates (3.96%) were resistant to colistin. Also, 39 isolates (38.61%) were considered as MDR, and eight isolates (7.92%) were considered as XDR. Further, 25 (24.75%) and 26 isolates (25.74%) were produced ESBL and carbapenemase enzymes, respectively. According to HRMA results, four isolates (3.96%) were positive for pmrA, three isolates (2.97%) were positive for mcr-1, 25 isolates (24.75%) were positive for blaTEM, 24 isolates (23.76%) were positive for blaSHV, 26 isolates (25.75%) were positive for blaKPC, and 23 isolates (22.77%) were positive for blaIMP genes. Furthermore, ST108 and ST250 showed the highest distribution in P. aeruginosa isolates. Also, ST217, ST1078, and ST3340 were reported as novel types in CRPA strains.Conclusion: Concerns about the prevalence of CRPA strains should be taken seriously. Also, our results showed that the mcr-1 gene plays a vital role in the distribution of ESBL and KPC-producing P. aeruginosa strains.Keywords: Pseudomonas aeruginosa, high-resolution melting curve analysis assay, HRMA assay, β-lactamases, colistin resistance, sequence types
