Genetic identity of aminoglycoside-resistance genes in Escherichia coli isolates from human and animal sources

Abstract

A bacterial collection (n=249) obtained in Hong Kong from 2002 to 2004 was used to investigate the molecular epidemiology of aminoglycoside resistance among Escherichia coli isolates from humans and food-producing animals. Of these, 89 isolates were gentamicin-sensitive (human n=60, animal n=29) and 160 isolates were gentamicin-resistant (human n=107, animal n=53). Overall, 84.1% (90/107) and 75.5% (40/53) of the gentamicin-resistant isolates from human and animal sources, respectively, were found to possess the aacC2 gene. The aacC2 gene for 20 isolates (10 each for human and animal isolates) was sequenced. Two alleles were found that were equally distributed in human and animal isolates. PFGE showed that the gentamicin-resistant isolates exhibited diverse patterns with little clonality. In some isolates, the aacC2 gene was encoded on large transferable plasmids of multiple incompatibility groups (IncF, IncI1 and IncN). An IncFII plasmid of 140 kb in size was shared by one human and three animal isolates. In summary, this study showed that human and animal isolates share the same pool of resistance genes.

Study of Aminoglycoside Resistance Genes in Enterococcus and Salmonella Strains Isolated From Ilam and Milad Hospitals, Iran

“…The witness for this claim is the frequent studies in which the presence of resistance, high-level aminoglycoside resistance, and other antibiotic resistance genes have been indicated in human, animals and food resources (25)(26)(27)(28). Overall, there are scarce reports on aminoglycoside resistance genes in Salmonella species (13).…”

Phenotypic and genotypic characteristics of antibiotic resistance of commensal Escherichia coli isolates from healthy pigs

“…The genes corresponding to the phenotypic resistance to important classes of antibiotics were identified. Resistance to streptomycin in all isolates was common (66.8%) and in the vast majority was associated with the presence of strA/strB genes, which were described as a part of Tn5993 transposon (10,11). Some of these strains were intI-positive.…”

“…In many previous studies, it was shown that the use of antibiotics is a risk factor for the selection of multi-resistant E. coli in both humans and animals (7,10,11,17). The results of the research examining a set of isolates derived from sows in farms with different levels of antibiotics consumption indicate that the vast majority of E. coli strains are multi-resistant and have a similar or the same resistance pattern.…”

“…Pathogenic and commensal strains of E. coli have different rates of resistance to antibiotics and can carry different resistance genes (11,15). Therefore, describing the antimicrobial resistance genes in commensal E. coli isolates documents the diversity of genes that could be transferred to dissemination to other bacteria (6,10).…”

“…Additionally, as a genetically diverse species, the flora includes, apart from the prevailing number of harmless commensals, pathogenic strains causing intestinal and general diseases in humans and animals (10). Pathogenic and commensal strains of E. coli have different rates of resistance to antibiotics and can carry different resistance genes (11,15).…”