Phenotypic and Genotypic Properties of Fluoroquinolone-Resistant, qnr-Carrying Escherichia coli Isolated from the German Food Chain in 2017

Abstract

Fluoroquinolones are the highest priority, critically important antimicrobial agents. Resistance development can occur via different mechanisms, with plasmid-mediated quinolone resistance (PMQR) being prevalent in the livestock and food area. Especially, qnr genes, commonly located on mobile genetic elements, are major drivers for the spread of resistance determinants against fluoroquinolones. We investigated the prevalence and characteristics of qnr-positive Escherichia (E.) coli obtained from different monitoring programs in Germany in 2017. Furthermore, we aimed to evaluate commonalities of qnr-carrying plasmids in E. coli. We found qnr to be broadly spread over different livestock and food matrices, and to be present in various sequence types. The qnr-positive isolates were predominantly detected within selectively isolated ESBL (extended spectrum beta-lactamase)-producing E. coli, leading to a frequent association with other resistance genes, especially cephalosporin determinants. Furthermore, we found that qnr correlates with the presence of genes involved in resistance development against quaternary ammonium compounds (qac). The detection of additional point mutations in many isolates within the chromosomal QRDR region led to even higher MIC values against fluoroquinolones for the investigated E. coli. All of these attributes should be carefully taken into account in the risk assessment of qnr-carrying E. coli from livestock and food.

Investigation of plasmid‐mediated quinolone resistance genes among clinical isolates of Klebsiella pneumoniae in southwest Iran

“…7,21,22 Although the main cause of quinolones resistance is a mutation in chromosomal topoisomerases, PMQR genes have been believed that play a significant role in the development of quinolone-resistant isolates due to their high horizontal transferability. 23 This study reports the high prevalence (88%) of PMQR genes in isolates, in which aac(6ʹ)-Ib-cr was detected as the most common gene. These results are in line with other studies conducted in Iraq, 7 Iran, 24 Korea, 25 and Thailand.…”

“…On a worldwide scale, the prevalence rate of quinolones resistance in K. pneumoniae isolates might be differed by geographic area; for example, resistance rates in Togo are 85.8%, 62.8% in Iraq, and 34.8% in Iran 7,21,22 . Although the main cause of quinolones resistance is a mutation in chromosomal topoisomerases, PMQR genes have been believed that play a significant role in the development of quinolone‐resistant isolates due to their high horizontal transferability 23 …”

Genomic and Transcriptomic Analysis of Bovine Pasteurella multocida Serogroup A Strain Reveals Insights Into Virulence Attenuation

“…Resistance development against fluoroquinolones can occur via various mechanisms ranging from chromosomal gene mutations to the specific transferable genes acquisition (28). The mutations in the chromosomal elements encoding the target enzyme (quinolone resistance determining region, QRDR) DNA gyrase (gyrA, gyrB) and topoisomerase IV (parC, parE) can considerably alter the susceptibility of the isolates, while the acquisition specific genes are always involved in overexpression of efflux pumps, alteration of the membrane permeability, and the expression of inactivation enzymes (28)(29)(30). Since foreign plasmids were not acquired in the genome, the acquired horizontal transfer of quinolone resistant genes was excluded.…”

Editorial for the Special Issue: “Antimicrobial Resistance and Molecular Tracing of Foodborne Pathogens”

“…In another study on commensal and ESBL-producing E. coli from the German monitoring on zoonoses from livestock and food, the occurrence of qnr genes in fluoroquinolone-/quinolone-resistant E. coli was determined. Similar to the Korean E. coli, Juraschek et al [8] also found a high number of fluoroquinolone-/quinolone-resistant isolates among ESBL-producing E. coli from livestock and food origin. So, the occurrence of E. coli co-carrying genes for both antibiotic classes seem to emerge.…”