Molecular Detection of Colistin Resistance Genes Mcr-1, 2, 3, 4 and Mcr-5 of Pseudomonas aeruginosa Isolated from Selected Hospital in Khartoum State

Abstract

Antimicrobial resistance is a major threat to human health and Pseudomonas is one of non-fermenting Gram-negative bacilli with clinically wide range of infections with a multidrug resistance characteristic, so there was re-emergence of use of Colistin -a drug with toxicity effects- as a last drug option and now there were wild world reports of its resistance. In this investigation, 50 clinical isolates Pseudomonas aerogenosa were collected from different Hospitals in Khartoum State (Royal care, Fedial, Alzaytouna, Omer Sawi, Al-raqi, Khartoum ENT, and Khartoum South North hospital Teaching Hospital). Traditional microbiological Techniques were used to re-identify bacterial isolates. All of these isolates were tested for resistance to common using antibiotic disc using the Kirby-Bauer disk diffusion technique according to CLSI guidance and investigated for the presence of mcr-1,2,3,4 and mcr-5 as plasmid mediate resistance genes to Colistin using multiplex PCR. The present cross-sectional study was conducted from January 2022 to June 2022. Out of the 50 isolates, 18 were isolated from urine samples, 11 from wound swabs, 6 from blood, 2 from high vaginal swabs, 8 from sputum, 3 from ear swabs, and 2 from body fluids, after culturing most strains showed pigmentation 32 (74%) and 18 (36%) were non-pigmented. Demographic data show male to female ratio was 0.85:1. Ages ranged from 4 to 76 years with an average of 49. Approximately one-third of 18 (36%) isolates were resistant to Aztreonam, 10 (20%) were resistant to Ciprofloxacin and Colistin, 11 (22%) were resistant to Gentamicin, Amikacin and Piperacillin/Tazobactam combinations, only one isolate was resistant to Imipenem. From 18 urine samples, 3 (19%) isolates were resistant to Norfloxacin. Only 14 (28%) isolates were MDR, most isolates 18 (36%) were sensitive to all antibiotics used. Mcr genes were isolated from 35 of P. aeruginosa (70%), mostly 28 (56%) was mcr-3, followed by 6 (12%) positive for mcr-2 and mcr-1 was found in one isolate (2%), mcr-4 and mcr-5 were not detected. Most mcr genes were present in Non-MDR isolates 31 (62%) and there was moderate negative correlation (R= -0.52) and p-value = 0.00 between present of mcr genes and drug resistance of isolates. There were no association between present of these mcr genes, age and gender of patient (p-value = 0.74, 0.24 respectively). This study was the first nationwide surveillance report on the detection of the mcr-3 gene among P. aeruginosa isolates from clinical samples in Sudan, this result indicates the spread of mcr genes in different Sudanese hospitals. In addition, this finding is higher than previous reports of mcr genes that have been reported in Sudan.