Screening of Colistin-Resistant Bacteria in Domestic Pets from France

Abstract

Background: Pets are the closest animals to humans with a considerable risk of zoonotic transmission. This study aimed to screen colistin-resistant bacteria from stools of dogs and cats from Marseille, France. Screening of mcr genes in pets has never been reported in France. Methods: Fecal samples (n = 157) were cultivated on the selective Lucie-Bardet Jean-Marc-Rolain medium (LBJMR). Bacteria were identified using Microflex LS MALDI-TOF. The antibiotic resistance phenotype was investigated for several antibiotics (β-lactams, aminoside, cephalosporine, tetracycline, and sulfonamide). PCR techniques were performed to detect mcr genes. Results: A total of 218 bacteria were identified. For cats, intrinsically colistin-resistant bacteria were significantly higher than mcr-1 gene carriers (n = 4). Dogs had more bacteria with the mcr-1 gene (n = 10). Furthermore, cats had a high prevalence of Gram-positive bacteria (GPB), whereas dogs had GNB equal to GPB. The diversity of identified bacteria was due to the constitution of the pets’ microorganisms. Even though colistin use is monitored in France, pets harbor various colistin-resistant bacteria. Additionally, in this geographical area, bacteria bearing mcr-1 gene from dogs and cats were detected for the first time. Conclusions: The current study opens a new perspective: the spread of colistin resistance is independent of colistin use. What are the most factors related to the emergence of colistin resistance? The surveillance of pets must be considered a priority to avoid the spread of mcr genes. It is important to know the contribution that pets make to the pool of multidrug-resistant mcr-1-containing bacteria.

Occurrence of mcr-1 and mcr-2 colistin resistance genes in porcine Escherichia coli isolates (2010–2020) and genomic characterization of mcr-2-positive E. coli

“…A study from Egypt identified mcr-2 in 2.5% of 122 Gram-negative bacterial isolates from wild birds (Ahmed et al, 2019). In pet animals, the prevalence of mcr-1 ranged from 0% to 12.5%, that of mcr-2 from 0% to 0.9% (Borowiak et al, 2020;Ilbeigi et al, 2021;Wang et al, 2021;Bertelloni et al, 2022;Hamame et al, 2022). In 2018, Partridge et al (2018 proposed a nomenclature scheme for mcr genes and their variants, therefore systematizing future registration of new discoveries of genes and allele numbers (Partridge et al, 2018).…”

Mobile Colistin Resistance (mcr) Genes in Cats and Dogs and Their Zoonotic Transmission Risks

“…Lastly, Enterobacter roggenkampii positive for the mcr-10 gene on an IncFIB plasmid was isolated in Japan from a pus sample [104]. In France, although the use of colistin in dogs is highly monitored, mcr-1 genes were detected in dogs in our recent work [105].…”

“…In addition to the isolation of mcr-producers, the direct detection of mcr genes in fecal samples from dogs and cats was also reported in China in 2017 and more recently in 2022 [108,109]. Another recent study in France showed that cats host bacteria harboring the colistin resistance mcr-1 gene [105].…”

Screening of colistin-resistant bacteria in livestock animals from France

“…The transmission of colistin resistance genes between dogs and their owners, containing significant quantities of positive E. coli with the co-occurrence of bla CTX-M and mcr genes, has been detected in China [ 60 ]. It should be noted that mcr genes in dogs and cats have recently been reported in France [ 30 ]. Colistin resistance has also frequently been found in river water and vegetable samples in Switzerland [ 61 ] and other studies have found mcr genes in water in Malaysia [ 62 ].…”

“…All bacteria with colistin MIC col ≥ 2 μg/mL as well as naturally resistant bacteria were subjected to several bio-molecular tests to screen for the following mcr genes: mcr- 1, mcr- 2 , mcr- 3, mcr- 4, mcr- 5 and mcr- 8 [ 30 ]. It should be noted that naturally colistin-resistant bacteria can carry mcr genes such as Proteus mirabilis [ 31 ].…”