Screening for fecal presence of colistin-resistant Escherichia coli and mcr-1 and mcr-2 genes in camel-calves in southern Tunisia

Abstract

Camels (Camelus dromedarius) are known to harbor multidrug resistant Gram-negative bacteria and to be involved in the transmission of various microorganisms to humans. Data on the occurrence of colistin resistant Escherichia coli as well as mobilized colistin resistance (mcr) genes in camels are lacking. We investigated the presence of colistin resistance and mcr (1–2) genes in E. coli from the feces of camels in Tunisia. Presumptive E. coli isolates from camel-calves in southern Tunisia were qualitatively screened for growth on Mueller–Hinton agar supplemented with 2 mg/L of colistin. The minimal inhibitory concentration of colistin was determined for isolates growing on this medium. All isolates were screened for the presence of the mcr-1 and mcr-2 genes by polymerase chain reaction without detecting any of these genes. However, one isolate was confirmed resistant to colistin and further testing of this isolate revealed it to be Enterobacter cloacae. Our study demonstrated absence of colistin resistance and of the mcr-1 and mcr-2 genes in E. coli isolated from camel feces in southern Tunisia. Thus, there is no evidence that camels represent a major source of mcr genes contamination for the local population or for tourists visiting southern Tunisia.

Antimicrobial resistant and extended-spectrum ß-lactamase (ESBL) producing Escherichia coli isolated from fecal samples of African dromedary camels

“…In our study, screening for plasmid-mediated colistin resistance genes mcr-1 through mcr-5 remained negative for all isolates (data not shown). The absence of plasmid-mediated colistin resistance confirms previous reports from Tunisia and suggests that camels do not play a major role as a reservoir for mcr harboring E. coli [38] . However, although we screened for all known variants at the time of analysis, novel mcr genes are emerging globally, and it cannot be excluded that variants including mcr-6 through mcr-8 may have been missed in this study.…”

Antimicrobial Resistance of Commensal Escherichia coli Isolated from Food Animals in Qatar

“…Moreover, a study from KSA reported that 26.9% of E. coli isolates from camel fecal samples are ESBL producer (Fadlelmula et al, 2016). In agreement with our findings, another research group from Tunisia reported the absence of colistin resistance genes mcr-1 and mcr-2 in E. coli isolated from camel fecal samples in southern Tunisia territory (Rhouma et al, 2018).…”

“…In another study from Tunisia, E. coli strains isolated from diarrheic and healthy camel fecal samples showed a high frequency of resistance to tetracycline (52.8%), and ampicillin (37.1%) (Bessalah et al, 2016). In another study from southern Tunisia demonstrated the absence of plasmid-mediated mobilized colistin resistance genes (mcr-1 and mcr-2) in E. coli isolated from camel feces (Rhouma et al, 2018). In an interesting study from coli isolated from camels with those of pathogenic E. coli isolated from human urinary tract infections (UTIs) (Fadlelmula, Al-Hamam, & Al-Dughaym, 2016).…”

Prevalence and Emergence of Extended-Spectrum Cephalosporin-, Carbapenem- and Colistin-Resistant Gram Negative Bacteria of Animal Origin in the Mediterranean Basin

“…The mcr-1 gene in these latter was associated with the IS Apl1 and was carried by IncP plasmid while the CMY-2 gene was located on an IncI1 plasmid type (Maamar et al, 2018 ). Furthermore, in this same country, a recent study revealed the absence of mcr-1 and mcr-2 positive Gram-negative bacilli in camel calves in southern Tunisia (Rhouma et al, 2018 ). Likewise, in Egypt, mcr-1 was detected in E. coli isolated from diseased chickens as well as from cows displaying subclinical mastitis (Khalifa et al, 2016 ; Lima Barbieri et al, 2017 ).…”