Detection of plasmid-mediated colistin resistance gene, mcr-1, in multidrug resistant E. Coli and Proteus mirabilis in water matrices in Syrian refugee camps in Lebanon

Abstract

More than 5.6 million individuals have fled from Syria after the civil war that started in 2011, and this is considered to be the greatest humanitarian emergency after World War II. Lebanon holds the largest number (∼1.5 million) of Syrian refugees per capita. Syrian refugees are distributed in random camps along the country, and the vast majority are getting exposed to unideal situations in terms of access to water, food and hygiene. Syrian refugees fall in the category of the most vulnerable population to multi-drug resistant infection due to stress and limited access to clean resources such as foods and water). Hence, the use of last-resort antibiotics such as colistin is possibly a common option that can be used to treat comex infections in this population. Although few studies assess the prevalence of multi-drug resistant bacteria, some studies reported the presence of mobile gene, mcr-1, that is responsible for colistin resistance in E. coli isolated from irrigation water and broilers in Lebanon. To assess the situation in the camps, eighteen composite samples were collected from two Syrian refugee camps in Beqaa area. Every sampling event covered three primary sources in each camp (drinking water, well water, and sewage water). All the samples were cultured on media that was previously supplemented with 4 μg-ml colistin to detect mcr-1 positive E. coli and Proteus mirabilis. Thirty-six E. coli and 8 Proteus mirabilis isolates were harvested and analyzed. All mcr-1 positive E. coli strains were multidrug-resistant and were negative for mcr 2 to 8; the minimum inhibitory concertation of colistin varied between 4-64 μg-ml. E. coli isolates (86percent, 81percent, 14percent, 6percent and 3percent) carried blaTEM, blaCTX-M, blaSHV, blaOXA48, and blaKPC respectively. Also, all the isolates carried class 1 integron gene and int1 but none was positive for class 2 integron gene, int2, blaNDM, and blaIPM. P. mirabilis strains that are intrinsically resistant to colistin were detected and carried mcr-1, blaTEM , int1, Class 1 In