Evaluation of mechanisms of colistin resistance in Klebsiella pneumoniae strains isolated from patients with urinary tract infection in ICU

• Published in: Iranian journal of microbiology 2022-02, Vol.14 (1), p.31-37
• Main Authors: Niazadeh, Mojtaba, Nikkhahi, Farhad, Robatjazi, Saeedeh, Javadi, Amir, Farzam, Seyed Amir, Babaei, Samaneh, Zeynali, Parisa
• Format: Article
• Language: English
• Subjects: Colistin; Intensive care units; Klebsiella pneumoniae; Mcr gene; MgrB; Original
• ISSN: 2008-3289; 2008-4447
• DOI: 10.18502/ijm.v14i1.8798

One of the major causes of urinary tract infections is Currently, few studies investigated the mechanisms of resistance to colistin in Iran. The current study aimed to determine the prevalence of plasmid and chromosome-mediated resistance to colistin in isolates. 177 urine samples were collected from patients with urinary tract infections hospitalized in the intensive care unit (ICU) of hospitals in the city of Qazvin. isolates were identified by standard biochemical methods, resistance to colistin among isolates were tested by disk diffusion and microbroth dilution methods. The chromosomal mutation and presence of the mcr genes in colistin-resistant were evaluated by PCR. Out of 177 samples, 65 were obtained from patients in the ICU. Six colistin-resistant isolates were isolated with MIC values ≥4 μg/mL, none of them was positive for . In 4 isolates, missense mutation in gene resulted in amino acid substitutions and in one isolate of gene was found intact gene. The results suggest that mutation was the main mutation among colistin-resistant isolates and plasmid-borne colistin resistance was not expanded among strains.