Antimicrobial Resistance In Enterococci Research Articles

Occurrence of Antimicrobial-Resistant Enterococcus spp. in Healthy Chickens Never Exposed to Antimicrobial Agents in Central Italy.

Enterococci are part of the natural flora of the gastrointestinal tract of mammals, including humans, birds and invertebrates. They can cause infection, mainly among hospitalized patients, as well as acquire and transfer antimicrobial resistance genes. The present study allowed the isolation of 98 Enterococcus (73.47% E. faecium, 23.47% E. faecalis, 3.06% E. avium) strains from 120-day-old healthy chickens that had never been treated with antimicrobials. Their antimicrobial resistance was evaluated by the agar disk diffusion method; high-level aminoglycoside (streptomycin and gentamicin) and vancomycin resistance were established using the microbroth dilution method. The highest percentages of resistant isolates were detected with quinupristin-dalfopristin (88.78%), rifampicin (64.29%), tetracyclines (45.92%), and enrofloxacin (41.84%). High percentages of susceptible strains were found with teicoplanin (100%), amoxicillin-clavulanic acid (97.96%), nitrofurantoin (94.90%), ampicillin (92.86%), chloramphenicol (90.82%), and linezolid (88.78%). About 60% of the strains were classified as MDR (multidrug-resistant). Moreover, PCR was carried out to investigate genes encoding for tetracyclines resistance determinants: tet(M), tet(L), tet(O), tet(K), and Int-Tn. Genes were detected in 68 (69.38%) strains: 36 were shown to be resistant with the agar disk diffusion method, while 28 were intermediate, and 2 were susceptible. The present study showed that chickens never treated with antimicrobials potentially harbor enterococci having phenotypic and genotypic characters of antimicrobial resistance.

Dissemination, virulence characteristic, antibiotic resistance determinants of emerging linezolid and vancomycin-resistant Enterococcus spp. in fish and crustacean

Enterococci are emerging nosocomial pathogens. Their widespread distribution causes them to be food contaminants. Furthermore, Enterococci can colonize various ecological niches and diffuse into the food chain via contaminated animals and foods because of their remarkable tolerance to unfavorable environmental circumstances. Due to their potential dissemination to humans, antimicrobial-resistant Enterococci in fish are a worldwide health issue. This study characterized AMR, ARGs, VAGs, gelatinase activity, and biofilm formation in Enterococcus spp. recovered from fish and seafood and evaluated potential correlations. 54 Enterococcus spp. strains(32.73 %)were isolated from 165 samples (75 Oreochromis niloticus, 30 Argyrosomus regius, and 60 Shrimp), comprising 30 Enterococcus faecalis (55.6 %) and 24 Enterococcus faecium (44.4 %) with total 32.73 % (54/165), The maximum prevalence rate of Enterococcus spp. was observed in Nile tilapia (34/54; 63 %), followed by shrimp (14/54; 25.9 %) and Argyrosomus regius (6/54; 11.1 %). The maximum prevalence rate of E. faecalis was observed in Nile tilapia (22/30; 73.3 %), followed by shrimp (8/30; 26.7 %) with significant differences. The prevalence rate of E. faecium was observed in Nile tilapia (12/24; 50 %), followed by shrimp (6/24,25 %). E. faecium is only isolated from Argyrosomus regius (6/24,25 %). Isolates exhibited high resistance against both tetracycline (90.7 %) and erythromycin(88.9 %), followed by gentamycin (77.8 %), ciprofloxacin (74.1 %), levofloxacin (72.2 %), penicillin (44.4 %), vancomycin (37 %), and linezolid (20.4 %). 50 strains (92.6 %) exhibited resistance to more than two antibiotics, 5 strains (10 %) were XDR, and the remaining 45 strains (90 %) were classified as MDR. 92.6 % of the isolates had MARindices >0.2, indicating they originated in settings with a high risk of contamination. Additionally, ten ARGs were identified, with tet(M) 92.6 %, followed by erm(B) (88.9 %), aac(6′)-Ie-aph(2″)-Ia(77.8 %), tet(K) (75.9 %), gyrA (74.1 %), blaZ (48.1 %), vanA (37 %), vanB (31.5 %), optrA (20.4 %), and catA(3.7 %). Biofilm formation and gelatinase activity were observed in 85.2 %, and 61.1 % of the isolates, respectively. A total of 11 VAGs were detected, with gelE as the most prevalent (83.3 %) followed by agg(79.6 %), pil (74.1 %), both sprE and asa1 (72.2 %), hyl (70.4 %), eps(68.5 %), EF3314 (57.4 %), ace (50 %), and cylA (35.2 %) with no detection of cylB. In conclusion, the emergence of linezolid-resistant -vancomycin-resistant enterococci recovered from Egyptian fish and shrimp, suggests that fish and seafood might participate a fundamental part in the emergence of antimicrobial resistance among humans.

Assessing the Risk of Antimicrobial Resistant Enterococcal Infections in Humans Due to Bacitracin Usage in Poultry

Bacitracin is an antimicrobial used in the feed or water of poultry in the U.S. for the prevention, treatment, and control of clostridial diseases such as necrotic enteritis. Concern has been raised that bacitracin can select for antimicrobial-resistant bacteria that can be transmitted to humans and subsequently cause disease that is more difficult to treat because of the resistance. The objective of the present study was to perform a quantitative risk assessment (QRA) to estimate the potential risk in the U.S. of human infection with antimicrobial-resistant Enterococcus faecalis and E. faecium derived from chicken and turkey products as a result of bacitracin usage in U.S. poultry. The modeling approach estimated the annual number of healthcare-associated enterococcal infections in the U.S. that would be resistant to antimicrobial therapy and that would be derived from poultry sources because of bacitracin use in poultry. Parameter estimates were developed to be “maximum risk” to overestimate the risk to humans. While approximately 60% of E. faecalis and E. faecium derived from poultry were predicted to possess bacitracin resistance based on the presence of the bcrABDR gene locus, very few human-derived isolates possessed this trait. Furthermore, no vancomycin or linezolid-resistant strains of E. faecalis or E. faecium were detected in poultry sources between the years 2002 and 2019. The model estimated the number of antimicrobial-resistant E. faecalis and E. faecium cases per year that might resist therapy due to bacitracin use in poultry as 0.86 and 0.14, respectively, which translates to an annual risk estimate for E. faecalis of less than 1 in 350 million and for E. faecium of less than 1 in 2 billion for members of the U.S. population. Even with the use of risk-maximizing assumptions, the results indicate that there is a high probability that the use of bacitracin according to label instructions in U.S. poultry presents a negligible risk to human health.

Prevalence and antimicrobial resistance of Enterococcus spp. isolated from animal feed in Japan.

The rising prevalence of antimicrobial resistance (AMR) of bacteria is a global health problem at the human, animal, and environmental interfaces, which necessitates the "One Health" approach. AMR of bacteria in animal feed are a potential cause of the prevalence in livestock; however, the role remains unclear. To date, there is limited research on AMR of bacteria in animal feed in Japan. In this study, a total of 57 complete feed samples and 275 feed ingredient samples were collected between 2018 and 2020. Enterococcus spp. were present in 82.5% of complete feed (47/57 samples), 76.5% of soybean meal (62/81), 49.6% of fish meal (55/111), 33.3% of poultry meal (22/66), and 47.1% of meat and bone meal (8/17) samples. Of 295 isolates, E. faecium (33.2% of total isolates) was the dominant Enterococcus spp., followed by E. faecalis (14.2%), E. hirae (6.4%), E. durans (2.7%), E. casseliflavus (2.4%), and E. gallinarum (1.0%). Of 134 isolates which were tested for antimicrobial susceptibility, resistance to kanamycin was the highest (26.1%), followed by erythromycin (24.6%), tetracycline (6.0%), lincomycin (2.2%), tylosin (1.5%), gentamicin (0.8%), and ciprofloxacin (0.8%). All Enterococcus spp. exhibited susceptibility to ampicillin, vancomycin, and chloramphenicol. Of 33 erythromycin-resistant isolates, only two showed a high minimum inhibitory concentration value (>128 μg/mL) and possessed ermB. These results revealed that overall resistance to antimicrobials is relatively low; however, animal feed is a source of Enterococcus spp. It is essential to elucidate the causative factors related to the prevalence of AMR in animal feed.

Antimicrobial resistance in Enterococcus isolated from western Canadian cow-calf herds

BackgroundData on antimicrobial resistance (AMR) in cow-calf herds is limited and there have been no Canadian studies examining AMR in Enterococcus in cow-calf herds. Enterococcus is a ubiquitous Gram-positive indicator of AMR for enteric organisms that is also important in human health. The objective of this study was to describe AMR in specific Enterococcus species of interest from cow-calf herds; highlighting differences in AMR among isolates from cows and calves and samples collected in the spring and fall. Isolates (n = 1505) were examined from 349 calves and 385 cows from 39 herds in the spring of 2021 and 413 calves from 39 herds and 358 cows from 36 herds in the fall of 2021. Enterococcus species were identified using Matrix-Assisted Laser Desorption Ionization Time-Of-Flight mass spectrometry (MALDI-TOF MS) and antimicrobial susceptibility testing was completed based on a prioritization scheme for importance to human health and using the National Antimicrobial Resistance Monitoring System (NARMS) Gram positive Sensititre broth microdilution panel.ResultsResistance was observed to at least one antimicrobial in 86% (630/734) of isolates from the spring and 84% (644/771) of isolates from the fall. The most common types of resistance across all species were: lincomycin, quinupristin/dalfopristin, daptomycin, ciprofloxacin, and tetracycline. However, the proportion of isolates with AMR varied substantially based on species. Multiclass resistance, defined as resistance to ≥3 antimicrobial classes after excluding intrinsic resistance, was highest in isolates from calves in the spring (6.9%) (24/349) and cows in the fall (6.7%) (24/357). Differences in resistance were seen between cows and calves in the spring and fall as well as across seasons, with no differences seen between cows and calves in the fall.ConclusionsWhile most Enterococcus isolates were resistant to at least one antimicrobial, questions remain regarding species differences in intrinsic resistance and the accuracy of certain antimicrobial breakpoints for specific Enterococcus spp. As a result, some species-specific AMR profiles should be interpreted with caution. Despite these constraints, Enterococcus species are important indicator organisms for AMR and resulting data can be used to inform stewardship initiatives.

Enterococcus species: insights into antimicrobial resistance and whole-genome features of isolates recovered from livestock and raw meat in Ghana.

Enterococcus spp. have gradually evolved from commensals to causing life-threatening hospital-acquired infections globally due to their inherent antimicrobial resistance ability and virulence potential. Enterococcus spp. recovered from livestock and raw meat samples were characterized using antimicrobial susceptibility testing and whole-genome sequencing. Isolates were confirmed using the MALDI-ToF mass spectrometer, and antimicrobial susceptibility was determined using the Kirby-Bauer disk diffusion method. Whole genome sequencing was performed on isolates resistant to two or more antibiotics. Bioinformatics analysis was performed to determine sequence types, resistance and virulence gene content and evolutionary relationships between isolates from meat and livestock samples, and other enterococci genomes curated by PATRIC. eBURST analysis was used to assign genomes to clonal complexes. Enterococcus spp. were predominantly E. faecalis (96/236; 41%) and E. faecium (89/236; 38%). Overall, isolates showed resistance to erythromycin (78/236; 33%), tetracycline (71/236; 30%), ciprofloxacin (20/236; 8%), chloramphenicol (12/236; 5%), linezolid (7/236; 3%), ampicillin (4/236; 2%) and vancomycin (1/236, 0.4%). Resistance to two or more antimicrobial agents was detected among 17% (n = 40) Enterococcus spp. Resistance genes for streptogramins [lsa(A), lsa(E), msr(C)], aminoglycosides [aac(6')-Ii, aph(3')-III, ant(6)-Ia, aac(6')-aph(2″), str], amphenicol [cat], macrolides [erm(B), erm(T), msr(C)], tetracyclines [tet(M), tet(L), tet(S)] and lincosamides [lsa(A), lsa(E), lnu(B)] were detected among the isolates. Genes for biofilm formation, adhesins, sex pheromones, cytolysins, hyaluronidase, oxidative stress resistance, quorum-sensing and anti-phagocytic activity were also identified. Potential plasmids with replicon sequences (rep1, rep2, repUS43, repUS47, rep9a, rep9b) and other mobile genetic elements (Tn917, cn_5536_ISEnfa1, Tn6009, ISEnfa1, ISEfa10) were detected. Clinically relevant E. faecium ST32 and ST416 clones were identified in meat samples. The occurrence of antimicrobial-resistant Enterococcus spp. in livestock and raw meat samples, carrying multiple resistance and virulence genes, including known clones associated with hospital-acquired infections, underscores the critical need for employing robust tools like whole genome sequencing. Such tools provide detailed data essential for ongoing surveillance efforts aimed at addressing the challenge of antimicrobial resistance with a focus on one health.

Early-life antibiotic usage and impact on the gut microbiota, including emergence of antimicrobial resistant Enterococcus

The early-life microbiota is an ‘immature’ and highly dynamic microbial ecosystem, which is central to infant health. Both perinatal and postnatal factors can impact the gut microbiota, with antibiotics proposed to cause short and longer-term disturbances. Antibiotics not only impact microbial community composition but also contribute to the overall antibiotic resistance profile, i.e. the ‘resistome’, and they may also enhance carriage of multi-drug-resistant bacteria. Given high antibiotic prescription practices in pregnant women and newborns this also contributes to the global threat of antimicrobial resistance. This review summarises the current literature on antibiotic usage and how this may impact the developing gut microbiota during early-life, including the influence of horizontal gene transfer on contributions to pathogenicity and resistance of gut bacteria. We also focus on Enterococcus spp. given their high levels in infants and their link with opportunistic infections that are a significant cause of morbidity and mortality during early-life. Finally, a perspective on the importance to antibiotic stewardship, and harnessing the microbiota itself for anti-infection therapies for reducing antibiotic usage are also covered.

The Emergence of Antimicrobial Resistance and Virulence Characteristics in Enterococcus Species Isolated from Bovine Milk.

Enterococcus spp., including E. faecalis and E. faecium, pose risks to dairy farms as opportunistic pathogens. The study evaluates antimicrobial resistance (AMR) and virulence characteristics of Enterococcus spp. isolated from bovine milk. Bile esculin agar was used to assess 1471 milk samples, followed by colony identification, gram staining, catalase tests, and 45 °C incubation. PCR analysis targeted E. faecalis and E. faecium in characteristic Enterococcus spp. colonies, with MALDI-TOF used for negative samples. Multiple tests, including disk diffusion, chromogenic VRE agar for vancomycin resistance, Vancomycin Etest® for MIC determination, and PCR for virulence factors (cylA, esp, efaA, ace, asa1, gelE, and hyl genes), were performed. Out of 100 identified strains, E. durans (30.66%), E. faecium (26.28%), and E. faecalis (18.25%) were predominant. AMR in Enterococcus spp. varied, with the highest rates against rifampicin (27%), tetracycline (20%), and erythromycin (18%). Linezolid (5%), vancomycin, ciprofloxacin, and teicoplanin (3% each) had lower prevalence. E. faecium and E. faecalis showed high AMR to rifampicin, erythromycin, and tetracycline. Thirty-two strains (18.98%) grew on VRE Chromoselect agar, while 4 (2 E. faecalis and 2 E. faecium) showed vancomycin resistance by MIC values. E. faecalis carried gelE (45.5%) and asa1 (36%), and E. gallinarum had 9.1% with the asa1 gene. Detecting resistant Enterococcus in bovine milk supports control strategies for enterococci on dairy farms, highlighting AMR concerns in the food chain.

Enterococcus spp. resistant to antimicrobials and biofilm formers in coalho cheese

The objective of this study was to accomplish a literature review on antimicrobial-resistant Enterococcus spp. and biofilm formers strains in coalho cheese originating from the Brazilian Northeast. The impact of the presence of enterococcal bacteria forming biofilm on coalho cheese and its impacts on public health for consumers of this type of food were observed. However, more microbiological studies on coalho cheese should be conducted due to its importance for the economy and public health.

Epidemiological characterization of the antimicrobial resistant Enterococcus isolates from four major rivers in South Korea

Epidemiological characterization of the antimicrobial resistant Enterococcus isolates from four major rivers in South Korea

Antimicrobial resistance characteristics and phylogenetic relationships of pleuromutilin-resistant Enterococcus isolates from different environmental samples along a laying hen production chain

Antimicrobial resistance in the laying hen production industry has become a serious public health problem. The antimicrobial resistance and phylogenetic relationships of the common conditional pathogen Enterococcus along the laying hen production chain have not been systematically clarified. 105 Enterococcus isolates were obtained from 115 environmental samples (air, dust, feces, flies, sewage, and soil) collected along the laying hen production chain (breeding chicken, chick, young chicken, and commercial laying hen). These Enterococcus isolates exhibited resistance to some clinically relevant antibiotics, such as tetracycline (92.4%), streptomycin (92.4%), and erythromycin (91.4%), and all strains had multidrug resistance phenotypes. Whole genome sequencing characterized 29 acquired antibiotic resistance genes (ARGs) that conferred resistance to 11 classes of antibiotics in 51 pleuromutilin-resistant Enterococcus isolates, and lsa(E), which mediates resistance to pleuromutilins, always co-occurred with lnu(B). Alignments with the Mobile Genetic Elements database identified four transposons (Tn554, Tn558, Tn6261, and Tn6674) with several ARGs (erm(A), ant(9)-la, fex(A), and optrA) that mediated resistance to many clinically important antibiotics. Moreover, we identified two new transposons that carried ARGs in the Tn554 family designated as Tn7508 and Tn7492. A complementary approach based on conventional multi-locus sequence typing and whole genome single nucleotide polymorphism analysis showed that phylogenetically related pleuromutilin-resistant Enterococcus isolates were widely distributed in various environments on different production farms. Our results indicate that environmental contamination by antimicrobial-resistant Enterococcus requires greater attention, and they highlight the risk of pleuromutilin-resistant Enterococcus and ARGs disseminating along the laying hen production chain, thereby warranting effective disinfection.

A Retrospective Analysis of Culture-Confirmed Enterococci Bloodstream Infections in South Africa, 2016-2020: A Cross-Sectional Study.

(1) Background: The emergence of multidrug resistance enterococci is a major public health concern. This study aimed to determine the prevalence and antimicrobial resistance of enterococci isolated from blood cultures over a five-year period (2016−2020) at public hospitals in South Africa. (2): Methods: A retrospective analysis of clinical enterococci isolated from bloodstream infection samples at the South African public hospitals was conducted. The ESKAPE dataset from January 2016 to December 2020 was obtained from the central data warehouse (CDW) at the National Health Laboratory Service (NHLS). (3): Results: Following de-duplication, a total of 130,352/306,592 organisms isolated from blood cultures were identified as ESKAPE pathogens. In this study, K. pneumoniae (25%; 33,082/130,352), was the most frequently isolated pathogen from blood cultures, followed by S. aureus (23%; 29,922/130,352) and enterococci (16%; 21,339/130,352). Of the enterococci cases, about 43% (9132/21,339) of cases were from the infants aged (<1-year old) and 32% (6745/21,339) from the adult patients. No changes observed in vancomycin, teicoplanin, and linezolid susceptibility; however, E. faecium and E. faecalis blood culture isolates remained highly susceptible (>97%) to these antibiotics. (4): Conclusions: The current study revealed a significant increase of E. faecalis and E. faecium blood culture isolates as compared to the previous national ESKAPE data. Low vancomycin resistance was observed. Continuous monitoring of antimicrobial resistant Enterococcus species is warranted in South Africa.

Effects of age and pasture type on the concentration and prevalence of tetracycline and macrolide resistant Enterococcus species in beef cow-calf production system

Enterococci are a normal flora of the gastrointestinal tracts of humans and animals. Enterococci can also cause life-threatening nosocomial infections. Antimicrobial-resistant Enterococcus species have been reported in the feedlot and dairy cattle productions and in meat and milk products, suggesting their foodborne importance. Cow-calf operations represent a significant segment in the beef production system by producing weaned calves. Weaned calves are brought into the feedlot to be finished for meat, and culled cows are also slaughtered for beef, primarily for ground beef products. Infection dynamics in the cow-calf operation can contribute to meat contamination. This study evaluated the effects of age and wheat grazing on the concentration and prevalence of a macrolide antibiotic erythromycin (ERYr) and tetracycline (TETr) resistant enterococci, associated resistance genes and species distribution in a cow-calf production system. In 2017 and 2018, 32 Angus breed cow-calf pairs were randomly assigned to feed on tall fescue or wheat pasture in two independent field experiments. During the grazing experiments of 2-3 weeks, fecal samples were collected weekly and cultured to enumerate, isolate and identify ERYr, TETr, and generic enterococci, using media supplemented with erythromycin, tetracycline or non-supplemented media, respectively. The two main species frequently associated with human illnesses, Enterococcus faecium and E. faecalis, were widely distributed in the cow-calf groups. Generic and TETr- enterococci were prevalent (96-100% prevalence) and abundant (3.2-4.9 log10 CFU/g) in the cow-calf population; however, ERYr enterococci were enumerable by direct plating only from a single cow despite being detected in at least 40% of the fecal samples after enrichment, showing their low abundance. TET- and ERY-resistance were mainly conferred by tet(M) and erm(B), respectively. Wheat grazing reduced the concentration of TETr enterococci and modified enterococcal species and resistance gene distributions. Hence, it is necessary to further investigate wheat grazing in cow-calf production as a potential strategy to mitigate antimicrobial resistance.

Isolation, Identification, Speciation, and Antibiogram of Enterococcus species by conventional methods and Assessment of the Prevalence of vana genotype among VRE

Enterococci are Gram-positive, ovoid cocci that can be found as diplococci or in short chains. These species are found in the typical microbiota of the intestine, oral cavity, vagina, and other areas. Despite being commensals with moderate virulence, these species have lately emerged as important nosocomial infections with increasing drug resistance particularly to vancomycin. This has resulted in their changing patterns of infection that are resistant to conventional antimicrobial therapy. The main objective of this study was to assess the frequency of the VanA genotype among Vancomycin Resistant Enterococci, as well as the isolation, identification, speciation, and antibiotic sensitivity pattern of Enterococci from various clinical specimens. In this six-month study, 500 different clinical specimens such as urine, blood, and pus were collected aseptically from patients suffering from urinary tract infection (UTI), septicemia, and pyogenic illnesses, and a total of 94 Enterococci strains were identified. These isolates were identified and speciated using traditional tests and biochemical processes. Following culture, the disc diffusion technique was used to determine their antibiotic susceptibility pattern, as suggested for common antibiotics. RCR was also used to evaluate the prevalence of the vanA gene among VRE isolates. 88.29% were E. faecalis, 7.88% were E. faecium, 2.12% were E. durans, 1.06 % was E. casseliflavus, and 1.06 % was E. gallinarum, out of a total of 94 isolates. Urine (70.21 %) yielded the most isolates, followed by blood (17.02 %) and pus (17.02 %). Female patients had a higher isolation rate of 73.40 % (69/94) than male patients, who had a rate of 26.59 % (25/94), and the majority of the Enterococcal isolates were from inpatients (62.77 %) rather than outpatients (37.23 %). 30 % of the isolates were hemolytic, whereas 70% were non-hemolytic. The isolates sensitivity patterns revealed that they were resistant to antibiotics such as ampicillin, ciprofloxacin, and gentamicin. The susceptibility test also included 30g discs of vancomycin. Vancomycin resistance is greatest in E. faecium (28 %) 6/83, followed by E. faecalis (8 %) 2\7. All other isolates were vancomycin-susceptible. Vancomycin-resistant isolates made up 8.51 % of the total. Barely urine isolates were tested for nitrofurantoin resistance, which was found to be only 5%. Linezolid sensitivity was found in all of the Enterococci. According to the PCR test for the vanA gene, among total VRE isolates 5 E. faecalis and 1 E. faecium isolates had vanA genotypes with bands of 473bp. A number of studies have revealed an increment in the infection rate and antimicrobial resistance of Enterococci. Elevated isolation rate of VRE has posed threat to therapeutic strategies as now only few antibiotics are susceptible to such isolates. It is thus imperative to execute measures that could stable the VRE augmentation lest a normal commensal would get the status of SARS-CoV-2

Antimicrobial-Resistant Enterococcus spp. in Wild Avifauna from Central Italy.

Bacteria of the genus Enterococcus are opportunistic pathogens, part of the normal intestinal microflora of animals, able to acquire and transfer antimicrobial resistance genes. The aim of this study was to evaluate the possible role of wild avifauna as a source of antimicrobial-resistant enterococci. To assess this purpose, 103 Enterococcus spp. strains were isolated from the feces of wild birds of different species; they were tested for antimicrobial resistance against 21 molecules, vancomycin resistance, and high-level aminoglycosides resistance (HLAR). Furthermore, genes responsible for vancomycin, tetracycline, and HLAR were searched. E. faecium was the most frequently detected species (60.20% of isolates), followed by E. faecalis (34.95% of isolates). Overall, 99.02% of the isolated enterococci were classified as multidrug-resistant, with 19.41% extensively drug-resistant, and 2.91% possible pan drug-resistant strains. Most of the isolates were susceptible to amoxicillin/clavulanic acid (77.67%) and ampicillin (75.73%), with only 5.83% of isolates showing an ampicillin MIC ≥ 64 mg/L. HLAR was detected in 35.92% of isolates, mainly associated with the genes ant(6)-Ia and aac(6′)-Ie-aph(2″)-Ia. Few strains (4.85%) were resistant to vancomycin, and the genes vanA and vanB were not detected. A percentage of 54.37% of isolates showed resistance to tetracycline; tet(M) was the most frequently detected gene in these strains. Wild birds may contribute to the spreading of antimicrobial-resistant enterococci, which can affect other animals and humans. Constant monitoring is essential to face up to the evolving antimicrobial resistance issue, and monitoring programs should include wild avifauna, too.

Species distribution and genes encoding antimicrobial resistance in enterococcus spp. isolates from rabbits residing in diverse ecosystems: A new reservoir of linezolid and vancomycin resistance.

Worldwide, studies regarding antimicrobial resistance in rabbits are scarce. In addition, it seems that rearing conditions have important impact on emergence and spread of antimicrobial-resistant bacteria. Thus, the authors sought to (1) assess the role of rabbits residing across diverse ecosystems as potential reservoirs of antimicrobial-resistant enterococci and (2) investigate the genetic background of detected resistances. Faecal samples from 60 healthy farmed rabbits (one farm), 35 laboratory rabbits and 31 wild rabbits were analysed. Overall, 97 enterococci isolates were accumulated, as follows: 44 E. faecium, 37 E. faecalis, 7 E. gallinarum, 5 E. durans and 4 E. avium. E. faecalis isolates were statistically associated with farm rabbits and wild rabbits (p<0.05). High rates of resistance were observed for tetracycline (60.8%; tetM [n=48; 81.3%], tetO [n=7; 11.8%] and tetL [n=1; 1.7%]), erythromycin (43.3%; msr(A) [n=14; 33.3%] and ermB [n=13; 31%]), ampicillin (29.9%), streptomycin (26.8%; ant(6)-Ia [n=3, 11.5%]) and vancomycin (21.6%; vanA [one E. faecium+one E. faecalis; 9.5%]). Low frequencies of resistance were observed for teicoplanin (9.2%), linezolid (8.2%), ciprofloxacin (7.2%) and gentamicin (1%; aac(6')-Ie-aph(2″)-Ia). Resistance to ampicillin and vancomycin was associated with laboratory rabbits (p<0.05). Int-Tn (Tn916/1545) was detected in 27 (27.8%) isolates, of which 10 isolates co-harboured tetM and ermB genes, while 16 comprised tetM. Findings indicate that clinically relevant enterococci species isolated from rabbits are frequently resistant to antimicrobials and harbour a range of genes associated with the Tn916/1545 family. This study highlights the high rates of antimicrobial-resistant enterococci from rabbits and the occurrence of both vancomycin- and linezolid-resistant isolates, potentially representing a very serious threat to human and animal health.

High prevalence of vancomycin non-susceptible and multi-drug resistant enterococci in farmed animals and fresh retail meats in Bangladesh.

The emergence of antimicrobial resistant Enterococcus spp., a main cause of untreatable nosocomial infection, in food animals and dissemination to humans is a public health risk. The study was performed to determine the prevalence and antimicrobial resistance, and virulence characteristics of Enterococcus faecalis and Enterococcus faecium in food animals and meats in Bangladesh. Enterococcus spp., were confirmed using sodA gene specific PCR, and antimicrobial resistance and virulence properties were characterized by PCR. Enterococcus spp. were recovered from 57% of the collected samples (n = 201/352). Farm samples yielded significantly higher (p ≤ 0.05) prevalence (62%) than that of retail meat samples (41%). E. faecalis (52%) is most frequently isolated species. Greater proportions of isolates exhibited resistance to tetracycline (74%), erythromycin (65%) and ciprofloxacin (34%). Fifty-one isolates are vancomycin non-susceptible enterococci (VNSE), of which forty-seven are MDR and twenty are linezolid resistant, a last line drug for VNSE. Virulence factors such as gelatinase (gelE), aggregation factor (asa1) and sex pheromone (cpd) are detected along with vancomycin resistance gene (vanA, vanB and vanC2/C3) in VNSE isolates. The high prevalence of MDR enterococci in food animals and retail meats may cause consumers infections with concomitant reduction of available therapeutic options.

Molecular characterization of antimicrobial resistance and virulence factors of Enterococcus faecalis from ducks at slaughterhouses

This study investigated the prevalence of antimicrobial resistant Enterococcus faecalis (E. faecalis) from ducks at slaughterhouses, analyzed antimicrobial resistance genes and virulence-associated genes of the isolates. Multilocus sequence typing (MLST) was performed to characterize their molecular characteristics. A total of 227 E. faecalis isolates (67.8%) were obtained from cecum (n = 114), cloaca (n = 50), skin (n = 59), and rinsed water (n = 4). These E. faecalis exhibited high level of resistance against tetracycline (95.6%), doxycycline (94.3%), linezolid (75.8%), erythromycin (72.2%), followed by norfloxacin (56.8%), vancomycin (38.3%), penicillin (36.1%), teicoplanin (30.8%). Lower level of resistance was found to high-level streptomycin (19.8%), imipenem (15.9%) and high-level gentamicin (5.7%). The vast majority of isolates (90.3%) were multidrug resistant (MDR). Moreover, the commonly observed resistance genes were optrA (90.7%) and ermB (90.3%), followed by aph(3’)-Ⅲ (86.8%), tetM (84.6%), acc(6’)-aph(2) (77.5%), blaZ (76.7%) and aac(6’)-Ie-aph(2”)-Ia (75.8%). The less frequently observed genes were vanC (19.8%), blaTEM (4.8%), vanM (2.6%), and vanA (0.4%). None of the strains carried aph(2”)-Ic and vanB genes. Furthermore, a high prevalence of ten virulence determinants was identified, and efaA (99.1%) was predominant, followed by eep (97.4%), srtA (96.9%), asa1 (95.6%), fsrB (92.1%), sprE (89.9%), aggA (63.9%), gelE (56.4%), esp (33.9%), and cylL (15.4%). Eleven isolates (4.9%) co-carried all of the tested virulence-associated genes. MLST analysis demonstrated that, E. faecalis isolates consisted of 12 known STs and 5 new STs, among which 6 of the identified STs were associated with nosocomial infection. Our data indicated that retail ducks serve as an important source of MDR E. faecalis with high pathogenicity potential, and suggested that transmission to humans could not be excluded.

Antimicrobial Resistance and Virulence Factor Gene Profiles of Enterococcus spp. Isolated from Giant Panda Oral Cavities.

IntroductionThe objective of this study was to determine the prevalence and characteristics of antimicrobial-resistant Enterococcus faecalis and E. faecium isolated from the oral cavities of captive giant pandas in China.Material and MethodsThe virulence-associated determinant and antimicrobial resistance genes were detected and antimicrobial susceptibility tests were performed on 54 strains of each bacterium.ResultsAll isolates showed 100% multidrug resistance. E. faecalis isolates showed a higher percentage of strains resistant to gentamicin (48.1%), vancomycin (55.6%), linezolid (100%), and streptomycin (33.3%) than E. faecium isolates. The resistance genes of Enterococcus spp. were present to highly varying extents according to antibiotic type, their presence breaking down for E. faecalis and E. faecium respectively as aac(6')/aph(2″) 5.56% and 5.56%; aph(3')-Ⅲ 0% and 14.81%; ant(6)-I 0% and 3.7%; ant(4')-Ia 0% and 64.81%; tetL 20.37% and 100%; vanA 92.59% and 46.3%; vanB 0% and 0%; cfr 0% and 90.74%; optrA 96.3% and 3.7%; blaZ 0% and 1.85%; blaTEM 0% and 0%; tetA 20.37% and 0%; tetC 24.07% and 100%; tetM 0% and 0%; ermA 12.96% and 100%; ermB 5.56% and 3.7%; and ermC 0% and 1.85%.Virulence-associated determinants were detected in this research, which typically include efaA, gelE, asa1, ace, cylA, esp and hyl; however, the latter three were not detected. High proportions of the isolates carried the efaA, gelE, asa1, and ace genes. Respectively for E. faecalis and E. faecium their detection was efaA 98.1% and 85.2%; gelE 98.1% and 87%; asa1 92.6% and 87%; and ace 87% and 85.2%.ConclusionThis is the first study on the potential disease risk and antimicrobial-resistant characteristics of E. faecalis and E. faecium isolates in giant panda oral cavities. The results of this study show that the antimicrobial resistance rate of Enterococcus spp. isolated from the oral cavity of captive pandas is very high, and thus needs to be monitored.

Nationwide Surveillance on Antimicrobial Resistance Profiles of Enterococcus faecium and Enterococcus faecalis Isolated from Healthy Food Animals in South Korea, 2010 to 2019

Intestinal commensal bacteria are considered good indicators for monitoring antimicrobial resistance. We investigated the antimicrobial resistance profiles and resistance trends of Enterococcus faecium and Enterococcus faecalis isolated from food animals in Korea between 2010 and 2019. E. faecium and E. faecalis, isolated from chickens and pigs, respectively, presented a relatively high resistance rate to most of the tested antimicrobials. We observed high ciprofloxacin (67.9%), tetracycline (61.7%), erythromycin (59.5%), and tylosin (53.0%) resistance in E. faecium isolated from chickens. Similarly, more than half of the E. faecalis isolates from pigs and chickens were resistant to erythromycin, tetracycline and tylosin. Notably, we observed ampicillin, daptomycin, tigecycline and linezolid resistance in a relatively small proportion of enterococcal isolates. Additionally, the enterococcal strains exhibited an increasing but fluctuating resistance trend (p < 0.05) to some of the tested antimicrobials including daptomycin and/or linezolid. E. faecalis showed higher Multidrug resistance (MDR) rates than E. faecium in cattle (19.7% vs. 8.6%, respectively) and pigs (63.6% vs. 15.6%, respectively), whereas a comparable MDR rate (≈60.0%) was noted in E. faecium and E. faecalis isolated from chickens. Collectively, the presence of antimicrobial-resistant Enterococcus in food animals poses a potential risk to public health.