Occurrence and characterization of quinolone resistant Escherichia coli from Norwegian turkey meat and complete sequence of an IncX1 plasmid encoding qnrS1

Abstract

Plasmid-mediated quinolone resistance (PMQR) is frequent among Escherichia coli from various food products and animals in several countries. The objective of this study was to characterize quinolone resistant E. coli (QREC) from Norwegian turkey meat regarding resistance profiles, genetic mechanisms for quinolone resistance, genetic relatedness, and to investigate whether PMQR genes were present. In total, 78 QREC were isolated by a selective method from 156 samples throughout 2013. Isolates were subjected to susceptibility testing, characterization of resistance mechanisms, serotyping, phylotyping and multi-locus variable-tandem repeat analysis (MLVA). All 78 isolates were resistant to ciprofloxacin, while 77 were also resistant to nalidixic acid. The nalidixic acid sensitive isolate had a resistance profile indicating the presence of a PMQR gene. Both PCR and whole genome sequencing confirmed the presence of a 47 304 kb IncX1 plasmid containing the qnrS1 gene. The mechanism conferring quinolone resistance in the remaining isolates was mediated by mutations in the quinolone resistance-determining region of the chromosomal gyrA gene and for most of the isolates also in the parC gene. Molecular typing by MLVA showed a high degree of genetic diversity, although four clusters dominated. Two clusters contained strains belonging to phylogroup D/serogroup O176, the third contained isolates of phylogroup B1/serogroup O19, whereas the fourth contained isolates of phylogroup B1/non-typeable serogroup. Isolates within the latter cluster had MLVA profiles identical to QREC isolated from day-old imported turkey parent animals investigated in a preliminary study at the Norwegian Veterinary Institute. This finding suggests that QREC obtained from turkey may have been introduced via import of breeding animals to Norway. This is the first time the qnrS1 gene is described from E. coli isolated from Norwegian turkey meat. Compared to available qnrS1 carrying plasmids in Genbank, the current IncX1 plasmid showed high degree of similarity to other IncX1 plasmids containing qnrS1 isolated from both Shigella flexneri and E. coli found in different geographical areas and sources. To conclude, this study showed that mutations in gyrA and parC are the main mechanism conferring quinolone resistance in E. coli isolated from Norwegian turkey meat, and that PMQR has not been widely dispersed throughout the E. coli population in Norwegian turkey.

Occurrence and characterization of ciprofloxacin‐resistantEscherichia colifrom bovine and ovine bulk tank milk samples in Turkey

“…Results of this study demonstrated that only minority (8.8%) of the isolates possessed PMQR genes and analysis of genes revealed that qnrS1 most frequently identified mechanism, followed by aac(6′)‐1b‐cr . The low presence of PMQR in this study is consistent with the findings from foods of animal origin in Norway (0–1.3%; Kaspersen et al, 2020; Slettemeås et al, 2019) and in Tunisia (17.6%; Kilania et al, 2020). Additionally, this is also consistent with the findings in human clinical practice in France (24/507; 4.7%; Muggeo et al, 2020), in Korea (10.7%; Kim et al, 2020), and in Taiwan (14.9%; Kao et al, 2016).…”

“…For example, a recent study by Obaidat, Bani Salman, Davis, and Roess (2018) has reported a 3.8% resistance rate for ciprofloxacin among intestinal E. coli isolates from fecal samples of healthy dairy cattles in Jordan (Obaidat et al, 2018). The results for occurrence rates cannot be directly comparable with previous studies, as the current study increased the sensitivity of test by using overnight enrichment and selective media with ciprofloxacin disk, which has been previously demonstrated to affect the outcome (Slettemeås et al, 2019). A recent Italian study involving 67 herds has found E. coli in 32.8% of BTM samples (Dell'Orco et al, 2019).…”

“…Consistent with this, similar resistance patterns have also been reported in ESBL producing E. coli strains originated from the foods of animal origin in Turkey (Kürekci et al, 2019). However, Cip R strains of E. coli isolated in 2013 from Norwegian poultry showed lower level of cross‐resistance to sulfamethoxazole (60.3%), ampicillin (57.7%), tetracycline (34.6%), and trimethoprim (34.6%; Slettemeås et al, 2019). Interestingly, the current study also revealed that the resistance pattern in Cip R E. coli isolates obtained from ovine samples did not have a similar distribution for gentamycin and chloramphenicol and amoxicillin/clavulanic acid.…”

Dissemination of Quinolone-Resistant Escherichia coli in the Norwegian Broiler and Pig Production Chains and Possible Persistence in the Broiler Production Environment

“…Resistance to these antimicrobials has previously been associated with qnrS1 (53). qnrS1 have previously been identified on large conjugative plasmids harbouring bla TEM-1B and tetA (54,55), which supports the significant positive correlations between qnrS1, bla TEM-1B and tetA. On the other hand, qnrB19 have been encoded on small, non-conjugative plasmids without any other resistance genes (56).…”

Comparative Genome Analyses of Wild Type- and Quinolone Resistant Escherichia coli Indicate Dissemination of QREC in the Norwegian Broiler Breeding Pyramid

“…Resistance can also develop from mutations of regulatory elements resulting in reduced influx or increased efflux of quinolones (Tavío del et al, 1999;Kern et al, 2000) or through acquisition of plasmid mediated quinolone resistance (PMQR) determinants, including qnr, oqxAB, qepA or aac(6 )-Ib-cr (Gosling et al, 2012;Machuca et al, 2014Machuca et al, , 2016Yamasaki et al, 2015). Additionally, PMQR determinants have been shown to coexist with resistance genes causing resistance toward other antimicrobials, which enables co-selection (Huang et al, 2012;Slettemeås et al, 2019). Quinolone resistance frequently develop in a stepwise fashion, where a single mutation in gyrA is often the initial step (Huseby et al, 2017).…”