Prevalence and Antimicrobial Resistance of Enterococci Isolated from Retail Meats in the United States, 2002 to 2014

Abstract

Bacteria of the genus are important human pathogens that are frequently resistant to a number of clinically important antibiotics. They are also used as markers of animal fecal contamination of human foods and are employed as sentinel organisms for tracking trends in resistance to antimicrobials with Gram-positive activity. As part of the National Antimicrobial Resistance Monitoring System (NARMS), we evaluated several retail meat commodities for the presence of enterococci from 2002 to 2014, and we found 92.0% to be contaminated. The majority of isolates were either (64.0%) or (28.6%), and the antimicrobial resistance of each isolate was assessed by broth microdilution. The resistance prevalences for several drugs, including erythromycin and gentamicin, were significantly higher among poultry isolates, compared to retail beef or pork isolates. None of the isolates was resistant to the clinically important human drug vancomycin, only 1 isolate was resistant to linezolid, and resistance to tigecycline was below 1%. In contrast, a majority of both (67.5%) and (53.7%) isolates were resistant to tetracycline. Overall, the robust NARMS testing system employed consistent sampling practices and methods throughout the testing period, with the only significant trend in resistance prevalence being decreased resistance to penicillin. These data provide excellent baseline levels of resistance that can be used to measure future changes in resistance prevalence that may result from alterations in the use of antimicrobials in food animal production. Enterococci, including and, are present in the guts of food-producing animals and are used as a measure of fecal contamination of meat. We used the large consistent sampling methods of NARMS to assess the prevalence of strains isolated from retail meats, and we found over 90% of meats to be contaminated with enterococci. We also assessed the resistance of the strains, commonly used as a measure of resistance to agents with Gram-positive activity, in foods. Resistance prevalence was over 25% for some antimicrobials and sample sources but was less than 1% for several of the most important therapeutic agents used in human medicine.

Antibiotic resistance profiles of vancomycin resistant enterococci in chicken meat samples

“…Lower prevalences have been reported from Tunisia (19) and Greece (12) In our study, the most prevalent species were determined as E. faecalis, followed by E. faecium, E. durans, E. gallinarum and E. casseliflavus. Similar preponderances from chicken meat samples have been reported previously from Tunisia (19), Brazil (8), USA (25), in contrast, some other studies from Scandinavia, Spain and Italy (6), Greece (12), E. faecium was stated as of the preponderant species. Varieties of preponderances can be linked with geographical diversities or typing techniques (14,21).…”

“…In our study 90% (18/20) of the VRE isolates were intermediate or resistant to linezolid and it also provides an alarming warning about treatment of VRE infections. As part of the NARMS (National Antimicrobial Resistance Monitoring System), Tyson et al (25) evaluated several retail meat commodities from 2002 to 2014, and found 92% of enterococci contamination. According to their study, none of the isolates was resistant to vancomycin, but only one isolate was resistant to linezolid, and resistance to tigecycline was below 1%.…”

Genotypes and Phenotypes of Enterococci Isolated From Broiler Chickens

“…Members of the genus Enterococcus, which includes presently about 40 recognized species, were initially classified as group D streptococci sharing several phenotypic and biochemical similarities, making their identification difficult (Yost et al, 2011). Enterococci have been proposed as fecal indicator bacteria for microbial source tracking (Byappanahalli et al, 2012;Boehm and Sassoubre, 2014) and are often used in tracking trends in resistance to antimicrobials for various resistance surveillance systems (Tyson et al, 2018a).…”

Study of VanA, B, C, D, E Genes in Vancomycin Resistant Enterococci Isolated from Retailed Dried Vegetables in Tehran, Iran

“…27 Tyson et al in a study on antimicrobial resistance of enterococci isolated from meats in the United States, 2002-2014, reported a multiple drug resistance pattern of the isolates to antibiotics such as erythromycin, gentamicin and tetracycline. 28 Furlaneto-Maia et al reported a high rate of enterococcal resistance to erythromycin (86.7%), vancomycin (80.0%), tetracycline (43.35) and gentamicin (33.3%) in Brazil. 29 Bacterial antibiotic resistance has become an urgent health problem worldwide.…”