Quinupristin-Dalfopristin Resistance inEnterococcus faeciumIsolates from Humans, Farm Animals, and Grocery Store Meat in the United States

Abstract

Three hundred sixty-one quinupristin-dalfopristin (Q-D)-resistant Enterococcus faecium (QDREF) isolateswere isolated from humans, turkeys, chickens, swine, dairy and beef cattle from farms, chicken carcasses, and ground pork from grocery stores in the United States from 1995 to 2003. These isolates were evaluated by pulsed-field gel electrophoresis (PFGE) to determine possible commonality between QDREF isolates from human and animal sources. PCR was performed to detect the streptogramin resistance genes vatD, vatE, and vgbA and the macrolide resistance gene ermB to determine the genetic mechanism of resistance in these isolates. QDREF from humans did not have PFGE patterns similar to those from animal sources. vatE was found in 35%, 26%, and 2% of QDREF isolates from turkeys, chickens, and humans, respectively, and was not found in QDREF isolates from other sources. ermB was commonly found in QDREF isolates from all sources. Known streptogramin resistance genes were absent in the majority of isolates, suggesting the presence of other, as-yet-undetermined, mechanisms of Q-D resistance.

Industrial Food Animal Production, Antimicrobial Resistance, and Human Health

“…Similar findings were reported by the FDA for nonpoultry meat products as well (25). Correlations among quinupristin-dalfopristin resistance in E. faecium isolates have been drawn between humans, farm animals, and grocery store meats in the United States (13).…”

Reduced susceptibility to quinupristin/dalfopristin in Enterococcus faecium in Greece without prior exposure to the agent

“…No transfer to E. faecium HM1070 was detected, whilst the spread of resistance appeared to be multiclonal. These results differ from the findings of other studies, where the Q/D resistance in E. faecium has been mainly attributed to vatE or vatD genes, which inactivate dalfopristin, resulting in high-level Q/D resistance (MIC > 16 mg/L) [10][11][12]. However, Q/D-resistant E. faecium isolates that are negative for previously described resistance genes were reported, although the genetic determinant remained unknown [10].…”

Quinupristin‐Dalfopristin Resistance in Gram‐Positive Bacteria: Mechanism of Resistance and Epidemiology

“…vatE is more commonly found in E. faecium and was originally found in an isolate from sewage in Germany [25]. Unlike vatD, vatE has also been found in E. faecium isolates from the United States; these have mainly been recovered from chicken and turkey farms and from retail poultry, but an isolate was also recovered from a human [26][27][28]. vatE has also been identified in quinupristin-dalfopristinresistant E. faecium isolated from retail meat, animals and humans in the community, and hospitalized patients in Europe [17,21,22].…”