Antimicrobial Resistance In Enterococci Research Articles

Water supply and feed as sources of antimicrobial-resistant Enterococcus spp. in aquacultures of rainbow trout (Oncorhyncus mykiss), Portugal

The role of European fish farms in the spread of antimicrobial-resistance in the environment and food chain, as well as possible sources of their contamination by clinically relevant antimicrobial-resistance bacteria is scarcely known. This study aimed to assess the contribution of Portuguese rural trout farms on dispersion of Enterococcus with antimicrobial-resistance and putative virulence genes in the environment and food chain, as well as to identify farms contamination sources. We also assessed the presence of Enterococcus with low-levels of antimicrobial-resistance using epidemiological cut-offs (ECOFFs). Enterococcus spp. (n=391) from water/sediment recovered upstream, within and downstream trout tanks, feed, trout (2 aquacultures; no antibiotic use) and marketed trout (8 supermarkets) showed variable resistance to tetracycline, erythromycin, ciprofloxacin, chloramphenicol, quinupristin-dalfopristin, nitrofurantoin or aminoglycosides. Antimicrobial-resistance rates were similar among upstream, within and downstream trout tank samples (P>0.05), positioning water-supplying aquacultures as a source of multidrug-resistant (MDR) strains. Nevertheless, predominance of MDR E. faecium in feed, trout tanks and trout comparing to upstream samples, suggests feed as an additional aquaculture contamination source. The observation of E. faecium and E. faecalis susceptible to ampicillin and gentamicin by clinical breakpoints but with low-levels of resistance to those antimicrobials by ECOFFs breakpoints is of concern, as they might evolve throughout secondary genetic events to resistance levels with human clinical impact. Multiple MDR clones carrying copper tolerance (tcrB/cueO), putative virulence or other genes often associated with clinical strains (e.g. E. faecium with IS16/ptsD/sgrA) were observed, some in distinct samples (e.g. upstream and within trout tanks). They included major human and animal Enterococcus lineages, suggesting human and non-aquatic animal origins. The results highlight the need to define the maximum acceptance level of antimicrobial-resistance genes/bacteria to assess water quality and to monitor antimicrobial-resistance strains on feed, essential requirements to maintain a sustainable aquaculture production.

Antimicrobial resistance of Enterococcus spp. isolated from Thai fermented pork in Chiang Rai Province, Thailand.

The aim of this study was to evaluate the prevalence of antimicrobial-resistant phenotypes and genes of Enterococcus spp. in order to explore the range of resistance profiles from Thai traditional fermented pork. A total of 120 Thai fermented pork specimens were collected in Chiang Rai, Thailand. Antimicrobial resistance among isolated enterococci to 11 antimicrobial agents was determined by the agar disk diffusion method. Antibiotic resistance genes from resistant phenotypes and virulence genes were observed. A total of 119 enterococci were found contaminating the collected samples. The most prevalent species was Enterococcus faecalis (68.9%), followed by Enterococcus hirae (16.0%), Enterococcus faecium (13.4%) and Enterococcus gallinarum (1.7%). The highest percentage of resistance was to ciprofloxacin (97.5%), followed by erythromycin (78.2%) and tetracycline (67.2%), whilst high-level gentamicin- and streptomycin-resistant isolates were of lower frequency (7.6% and 22.7%, respectively). All isolates were susceptible to the clinically important agents vancomycin and teicoplanin. Overall, a relatively high frequency of multidrug-resistant (MDR) enterococci was observed (76.2%). Antimicrobial-resistant phenotypes were found to carry aacA-aphD, addE, erm(B), mefA/E, cat, tet(L) and tet(M) resistance genes. Virulence genes were also evaluated and the gelE gene was found to be the most common (37.8%). These data highlight the importance of MDR enterococci in fermented pork in Thailand. This is the first report to detect the unusual species E. hirae carrying the mefA/E macrolide resistance gene. These clinically important and unusual enterococci isolates from Thai fermented pork could be a source of transferable resistance genes to other bacteria.

Antimicrobial resistance status of Enterococcus from Australian cattle populations at slaughter.

Antimicrobial agents are used in cattle production systems for the prevention and control of bacterial associated diseases. A consequence of their use is the potential development of antimicrobial resistance (AMR). Enterococcus faecium and Enterococcus faecalis that are resistant to antimicrobials are of increased concern to public health officials throughout the world as they may compromise the ability of various treatment regimens to control disease and infection in human medicine. Australia is a major exporter of beef; however it does not have an ongoing surveillance system for AMR in cattle or foods derived from these animals. This study examined 910 beef cattle, 290 dairy cattle and 300 veal calf faecal samples collected at slaughter for the presence of enterococci. Enterococcus were isolated from 805 (88.5%) beef cattle faeces, 244 (84.1%) dairy cattle faeces and 247 (82.3%) veal calf faeces with a total of 800 enterococci subsequently selected for AMR testing. The results of AMR testing identified high levels of resistance to antimicrobials that are not critically or highly important to human medicine with resistance to flavomycin (80.2%) and lincomycin (85.4–94.2%) routinely observed. Conversely, resistance to antibiotics considered critically or highly important to human medicine such as tigecycline, daptomycin, vancomycin and linezolid was not present in this study. There is minimal evidence that Australian cattle production practices are responsible for disproportionate contributions to AMR development and in general resistance to antimicrobials of critical and high importance in human medicine was low regardless of the isolate source. The low level of antimicrobial resistance in Enterococcus from Australian cattle is likely to result from comprehensive controls around the use of antimicrobials in food-production animals in Australia. Nevertheless, continued monitoring of the effects of all antimicrobial use is required to support Australia’s reputation as a supplier of safe and healthy food.

Multiplex PCR based genotypic characterization of pathogenic vancomycin resistant Enterococcus faecalis recovered from an Indian river along a city landscape.

BackgroundEnterococci are normal commensals of human gut, but vancomycin-resistant enterococci (VRE) are a severe threat to human health. Antimicrobial-resistant enterococci have been reported previously from Indian surface waters. However, the presence of antimicrobial resistance and virulence markers in Enterococcus faecalis, the most dominant enterococci is yet to be investigated.ObjectivesThe goal of this study was to analyse concentration of enterococci and distribution of antimicrobial resistance and virulence markers in E. faecalis isolates from river waters along an important north Indian city landscape.MethodsWe enumerated enterococci in river water samples (n = 60) collected from five sites across the Lucknow city landscape using the most probable number and membrane-filtration methods. The antimicrobial sensitivity profile of E. faecalis isolate was generated with the Kirby-Bauer antimicrobial disc diffusion assay. The multiplex PCR was used for genotypic characterization of vancomycin-resistance and virulence in E. faecalis isolates.ResultsEnterococci density (p < 0.0001) increased from up-to-down-stream sites. Multiplex PCR based genotypic characterization has shown a significant distribution of virulence-markers gelE, ace or efaA in the E. faecalis isolates (p < 0.05). The range of antimicrobial-resistance varied from 5 to 12 in the landscape with the frequency of vancomycin-resistant E. faecalis (VRE) ranging from 22 to 100 %.ConclusionThe occurrence of pathogenic VRE in river Gomti surface water is an important health concern. The observed high background pool of resistance and virulence in E. faecalis in river waters has the potential to disseminate more alarming antimicrobial resistance in the environment and poses serious health risk in developing countries like India as VRE infections could lead to increased cost of healthcare.Electronic supplementary materialThe online version of this article (doi:10.1186/s40064-016-2870-5) contains supplementary material, which is available to authorized users.

Antimicrobial resistance and virulence profiles of Enterococcus spp. isolated from horses in korea.

Antimicrobial-resistant (AR) enterococci have emerged as leading nosocomial pathogens. Transmission of AR Enterococci from animals to humans has been demonstrated. However, there is limited information on the transmission of enterococci from horses to humans. To address this issue, we characterized 260 enterococci isolated from horse-associated samples in Korea in 2013 based on their AR profiles and virulence traits. AR profiling revealed an average ratio of AR enterococci of 23.8%. Seven isolates (2.7%) were multidrug-resistant Enterococcus faecalis. Most tetracycline-resistant enterococci harbored either tetM or tetL or both genes; genes conferring resistance to other antimicrobials were detected at low rates. Biofilm formation and gelatinase activity were observed in 51.1% and 47.7% of isolates, respectively; most were E. faecalis harboring the gelE gene. Evidence of transmission of AR enterococci between horses and their environments was provided by pulsed-field gel electrophoresis, and highlights the risk of AR enterococcus transmission to horse riders and handlers through close contact.

Evaluation of Antimicrobial Susceptibility Among Enterococcus Species by E-Test Method at Khatam-ol-Anbia Hospital During 2013 – 2014

Background: Over the past decade, Enterococci have been shown to be an important cause of nosocomial and community-acquired infections. Inappropriate use of antibiotics led to changes in the pattern of antibiotic resistances in Enterococcus species. Unfortunately, no study has been performed in Iran in recent years regarding the antimicrobial resistance of Enterococci using the E-test method as a base. We must gain sufficient knowledge about the regional antibiotic resistances related to Enterococcus so that we can monitor the prevalence and antimicrobial resistance of Enterococcus by administering appropriate treatments. Objectives: The objective of this study was to evaluate the antimicrobial susceptibility among Enterococcus species by the E-test method at Khatam-ol-Anbia hospital during 2013 - 2014. Patients and Methods: This descriptive cross-sectional study was carried out during 2013 - 2014. All clinical samples were collected from the intensive care unit (ICU) and general wards of Khatam-ol-Anbia hospital. All Enterococcus species were detected via biochemical testing. Antimicrobial susceptibility and minimum inhibitory concentration (MIC) were determined via disk diffusion and the E-test method. We used descriptive statistics to analyze the data. Results: A total of 53 Enterococci were isolated from clinical samples of blood, urine, wounds, sputum, and cerebrospinal fluid (CSF) over a two-year period from the ICU and general wards. The isolated Enterococcus species were 77.35% E. faecalis, 18.86% E. faecium, and 3.77% other species. Species evaluated by E-test were resistant to imipenem, ampicillin, co-trimoxazole, gentamicin, rifampicin, vancomycin, linezolid, and teicoplanin; 54%, 68%, 100%, 93.8%, 60.4%, 39.6%, 0%, and 29.2%, respectively. Among the strains of enterococci, 90.9% of E. faecium and 20% of E. faecalis species were resistant to vancomycin. Conclusions: According to these findings, antibiotic-resistance patterns have changed, and vancomycin resistance, especially among E. faecium, is rising because of nosocomial infections. Consequently, it has become a serious subject for patients admitted into a hospital.

Antimicrobial resistance in Enterococcus spp. isolated from laying hens of backyard poultry floks

Enterococci belonging to human and animal gastrointestinal flora are widely-distributed in the environment. They are opportunistic bacteria that can cause severe infections, with the ability to acquire, express and transfer antimicrobial resistance. The aim of the present study was to investigate antimicrobial resistance profiles of Enterococcus spp. strains isolated from cloacal swabs of laying hens of small backyard flocks. Susceptibility to 21 antimicrobial agents was tested by the disc diffusion method in 115 Enterococcus spp. strains. Vancomycin and ampicillin minimum inhibitory concentrations and high-level aminoglycoside resistance tests were also performed. Isolates showed resistance mainly to aminoglycosides, eritromycin, fluoroquinoles, tetracycline and nitrofurantoin. 19 (16.5%) isolates showed a high level of resistance to streptomycin, but no high level resistance to gentamycin. No significant resistance was detected for vancomycin. Several strains (45; 39.1%) showed combined resistance to macrolides, lincosamides and streptogramin B. 61 (53%) isolates were classified as multidrug-resistant (MDR) and 6 (5.2%) strains as possibly extensively drug-resistant (XDR). E. faecium was the most prevalent antimicrobial resistant species, followed by E. faecalis and E. durans. The results show that the risk of dissemination of antimicrobial resistant enterococci is related not only to the birds of large commercial flocks, but also to the birds of small backyard flocks. Thus, laying hens of hobby flocks, which share the outside environment with people, could represent a hazard for public health by providing a conduit for the entrance of resistance genes into the community.

Isolation and Biochemical Fingerprinting of Vancomycin-Resistant Enterococcus faecium From Meat, Chicken and Cheese.

Background:Vancomycin-resistant enterococci (VRE) are important nosocomial pathogens and food chain has been considered as an assumed source for dissemination of VRE to human.Objectives:The presence of VRE isolates from food samples and typing of these isolates with Phene plate, a biochemical fingerprinting method, were investigated.Materials and Methods:Thirty samples of meat, chicken and cheese were analyzed for VRE during 2010. Antibiotic susceptibility tests and minimum inhibitory concentration (MIC) were also examined. VRE isolates were typed with the Phene plate system (PhPlate), a biochemical fingerprinting method.Results:A total of 70 VRE isolates were obtained and identified as Enterococcus faecium by species-specific PCR. All the isolates carried vanA, while none of them harbored vanB. The VRE isolates included 35, 27, and 8 isolates from meat, chicken and cheese, respectively. Typing with the PhPlate revealed a diversity index of 0.78 for E. faecium, containing 10 common and four single types. The results of antibiotic susceptibility and MIC tests showed an increased resistance to ciprofloxacin, erythromycin, ampicillin and gentamicin, to which, 100%, 100%, 100%, and 95% of VRE isolates were resistant, respectively. Only 5% of the isolates were resistant to chloramphenicol and the MIC of the isolates for vancomycin and teicoplanin was ≥ 256 µg/mL and for gentamicin-resistant isolates it was 1024 µg/mL. Conventional and molecular identification tests exhibited that all the isolates were E. faecium carrying vanA. None of the isolates harbored vanB.Conclusions:The results showed that enterococci are common contaminants in food. Indeed, this study indicates a high prevalence of multidrug-resistant enterococci in food of animal origin in Iran. Isolating some persisting enterococcal isolates revealed that continuous surveillance of antimicrobial resistance in enterococci from food is essential.

Prevalence of Antimicrobial Resistance in Enterococci and Escherichia coli in Meat Chicken Flocks During a Production Cycle and Egg Layer Pullets During Rearing

Avian Pathogenic Escherichia coli (APEC) and some enterococci are important zoonotic pathogens associated with poultry and some human illnesses. This study was conducted to evaluate the phenotypic antibiotic resistance and resistance genes during the production cycle of healthy free-range meat chickens and egg layer pullets raised in two different controlled farms in South Australia, in particular to determine at which point in the production cycle birds become colonized with antibiotic resistant bacteria. Antibiotic resistance was investigated in faecal E. coli (206) and enterococcal (252) isolates by agar dilution and polymerase chain reaction. Southern hybridization was carried on plasmids from selected multi-resistant E. coli isolates to determine the location of resistance genes. Our results revealed that birds are colonized with resistant bacteria encoding various resistance genes from a very early age. Resistance to ampicillin and tetracycline (and associated resistance genes) were the most frequently detected resistances in E. coli isolates from egg layer pullets and free-range meat chickens. Phenotypically resistant enterococcal isolates from 3-5 days old chickens carried genetic determinants for resistance to tetracycline, bacitracin and tylosin. Whilst statistical analysis revealed there was no significant differences (p<0.05) with the phenotypic resistance observed in the E. coli and enterococcal isolates from meat chickens and egg layer pullets, a significant difference was observed in resistant E. coli isolates containing blaTEM and tet genes. This study demonstrates that newly hatched chicks are already colonized with resistant bacteria which persist through the production cycle and can potentially contaminate eggs and chicken carcasses. This study also confirms that poultry are a potential source of pathogenic E. coli strains.

Identification and antimicrobial resistance of Enterococcus spp. isolated from the river and coastal waters in northern Iran.

As fecal streptococci commonly inhabit the intestinal tract of humans and warm blooded animals, and daily detection of all pathogenic bacteria in coastal water is not practical, thus these bacteria are used to detect the fecal contamination of water. The present study examined the presence and the antibiotic resistance patterns of Enterococcus spp. isolated from the Babolrud River in Babol and coastal waters in Babolsar. Seventy samples of water were collected in various regions of the Babolrud and coastal waters. Isolated bacteria were identified to the species level using standard biochemical tests and PCR technique. In total, 70 Enterococcus spp. were isolated from the Babolrud River and coastal waters of Babolsar. Enterococcus faecalis (68.6%) and Enterococcus faecium (20%) were the most prevalent species. Resistance to chloramphenicol, ciprofloxacin, and tetracyclin was prevalent. The presence of resistant Enterococcus spp. in coastal waters may transmit resistant genes to other bacteria; therefore, swimming in such environments is not suitable.

Antimicrobial susceptibility of enterococcal species isolated from antibiotic-treated dogs and cats.

ABSTRACTIn this study, we examined the antimicrobial susceptibility of the enterococci isolated from dogs and cats in Japan during 2011–2012. Fecal samples were collected from 84 dogs and 16 cats that underwent antibiotic treatment. Enterococci were detected in 70 of 84 dogs (83.3%) and 7 of 16 cats (43.8%). The most prevalent Enterococcus species was Enterococcus faecalis (64.9%); Enterococccus faecium and Enterococcus durans were also isolated from 14 of 77 (18.2%) and 5 of 77 (6.5%) of these animals, respectively. The most active resistance was observed for erythromycin (44.2%) and oxytetracycline (44.2%), and there was considerable resistance to lincomycin (41.6%), gentamicin (31.2%) and kanamycin (31.2%). Compared with the results of a similar study conducted in 2006 and 2007, enterococci susceptibility to enrofloxacin and ampicillin had significantly increased. Enterococcus gallinarum harboring vanC1 and Enterococcus casseliflavus harboring vanC2/3 were isolated from 4 of 77 enterococcal isolates. However, no enterococcal isolates were resistant to vancomycin. Multidrug resistance was found for as few as two and as many as nine antimicrobials regardless of the class. These results demonstrate that dogs and cats treated with antibiotics are commonly colonized with antimicrobial-resistant enterococci.

Biocide and copper tolerance in enterococci from different sources.

Antimicrobial resistance in enterococci is a matter of concern. A collection of 272 strains (including 107 Enterococcus faecalis and 165 Enterococcus faecium strains) isolated from meat and dairy products, seafood, vegetable foods, wildflowers, animal feces (ewe, goat, horse, mule), and hospitals were tested for sensitivity to biocides of different classes (quaternary ammonium compounds, a bisphenol, and a biguanide) and copper sulfate. Most isolates were inhibited at 25 mg of benzalkonium chloride or cetrimide per liter or at 2.5 mg of hexadecylpyridinium chloride per liter. Few isolates had MICs higher than 25 mg/liter for benzalkonium chloride (2.2%), cetrimide (0.74%), or hexadecylpyridinium chloride (0.37%), although they were all inhibited at 250 mg/liter. The population response to triclosan was very homogeneous, and most isolates (98.16%) were inhibited at 250 mg of triclosan per liter. Chlorhexidine showed the greatest variability, with MICs in a range from 2.5 to 2,500 mg/liter. Remarkably, 74.57% of isolates from clinical samples required 2,500 mg of chlorhexidine per liter for inhibition, compared to much-lower concentrations required for most isolates from other sources. Enterococci were inhibited by copper sulfate in a concentration range from 4 to 16 mM, with no bimodal distribution. However, most isolates required 12 mM (41.91%) or 16 mM (47.43%) for inhibition. The highest percentages of isolates requiring 16 mM CuSO4 were from vegetable foods, seafood, and wildflowers. The results from the present study suggest intermediate levels of copper tolerance and a low incidence of biocide tolerance in the enterococci investigated, except for chlorhexidine in clinical isolates.

Molecular characterization of high-level gentamicin-resistant Enterococcus faecalis from chicken meat in Korea

Because the intrinsically antimicrobial-resistant Enterococcus has acquired high-level aminoglycoside resistance genes, treating enterococcal infections is difficult. In this study, of the 101 food-borne Enterococcus faecalis isolates collected from retail chicken meat between 2003 and 2010, 11 high-level gentamicin-resistant (HLGR) E. faecalis isolates (MICs>2,048μg/mL) were found. Molecular characterization was performed to determine the basis of this resistance. All HLGR E. faecalis isolates encoded aac(6′)-Ie–aph(2″)-Ia and harbored at least 3 virulence traits in the asa1, esp, gelE, efaA, ace, and cylA genes. Pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) were performed to characterize their molecular epidemiology. A total of 8 sequence types (STs), including 3 novel STs, were identified (ST35, ST82, ST116, ST202, ST300, ST403, ST407, and ST420). ST82, which is associated with amyloid arthropathy in poultry, was the most prevalent ST among HLGR E. faecalis isolates (4 out of 11 isolates, 36.4%); all other STs were identified in the isolates as well. The STs of food-borne HLGR E. faecalis in this study have been confirmed as corresponding to clinical isolates in the MLST database (DB), except for ST300 and the new STs. Three out of 11 isolates belonged to CC116, including ST116, ST407, and ST420. This study characterized HLGR E. faecalis isolates and provided evidence for the spread of HLGR E. faecalis with virulence factors to chicken sources in Korea. The emergence of food-borne HLGR E. faecalis suggests that chicken could be a potential source of transmission of antimicrobial resistance and virulence factors.

Antimicrobial resistance in Enterococcus spp. isolated from environmental samples in an area of intensive poultry production.

Enterococcus spp. from two poultry farms and proximate surface and ground water sites in an area of intensive poultry production were tested for resistance to 16 clinical antibiotics. Resistance patterns were compared to assess trends and possible correlations for specific antimicrobials and levels of resistance. Enterococci were detected at all 12 surface water sites and three of 28 ground water sites. Resistance to lincomycin, tetracycline, penicillin and ciprofloxacin in poultry litter isolates was high (80.3%, 65.3%, 61.1% and 49.6%, respectively). Resistance in the surface water to the same antibiotics was 87.1%, 24.1%, 7.6% and 12.9%, respectively. Overall, 86% of litter isolates, 58% of surface water isolates and 100% of ground water isolates were resistant to more than one antibiotic. Fifty-four different resistance patterns were recognised in isolates obtained from litter and environmental samples and several E. faecium and E. faecalis isolates from litter and environment samples shared the same resistance pattern. Multiple antibiotic resistant (MAR) indices calculated to assess health risks due to the presence of resistant enterococci suggested an increased presence of antibiotics in surface water, likely from poultry sources as no other wastewater contributions in the area were documented.

Virulence and antimicrobial resistance in enterococci isolated from urinary tract infections.

Urinary tract infection (UTI) is the most common nosocomial infection among hospitalized patients. Meanwhile, most frequent infections involving enterococci affect the urinary tract. The aims of this study were to investigate the susceptibility pattern of isolated enterococci from UTI and the prevalence of virulence genes. The study used enterococci isolated from urinary tract infections obtained from 3 university teaching hospitals in Northwest Iran. The antimicrobial susceptibility of the strains was determined using the disc diffusion method. Multiplex PCR was performed for the detection of genus- species specific targets, and potential virulence genes. Of 188 enterococcal isolates, 138 (73.4%) and 50 (26.6%) were Enterococcus faecalis and E. faecium, respectively. Antibiotic susceptibility testing showed high resistance to amikacin (86.2%), rifampicin (86.2%) and erythromycin (73.9%), irrespective of species. In total, 68.1% were positive for gelE, and 57.4%, 53.2%, 56.4%, and 52.1% of isolates were positive for cpd, asa1, ace, and esp, respectively. The study revealed that most of UTI isolates were multidrug resistance against the antibiotics tested and antibiotic resistance was more common among E. faecium isolates than E. faecalis. A significant correlation was found between UTI and the presence of gelE among E. faecalis strains (p < 0.001).

Prevalence and antimicrobial resistance of Enterococcus spp. isolated from meat and fishery production in Korea

From February to October 2011, 209 samples of retail raw meat and fishery products were randomly obtained from 41 grocery stores in Korea and cultured for the presence of Enterococcus spp. Ninety-six enterococcal isolates were recovered from 76 samples, with contamination rates ranging from 18.5% in fishery product samples to 43.9% in chicken samples. Antimicrobial disk susceptibility testing was conducted according to the Clinical and Laboratory Standards Institute protocol. The antibiotic resistance rates of the 96 enterococci isolates were as follows: tetracycline (TE) 77.1%; erythromycin (E) 50%; rifampin (RD) 44.8%; and vancomycin (VAN) 9.4%. Disk diffusion showed that 9 isolates were resistant to vancomycin. The minimum inhibitory concentration (MIC) was ≥32 μg/mL for all 9 isolates, and all were resistant to vancomycin. Among the 9 vancomycin-resistant enterococci (VRE) identified, the vanA gene was carried by 1 Enterococcus durans strain and the vanB gene was carried by 2 Enterococcus faecium, and 1 Enterococcus hirae strains. Further genotyping of the VRE isolates using pulsed-field gel electrophoresis (PFGE) revealed extensive heterogeneity. The VRE were recovered from various animal sources with a particularly high prevalence of E. faecium found in fishery products and chicken.

Prevalence and antimicrobial resistance of Enterococcus spp and Staphylococcus spp isolated from surfaces in a veterinary teaching hospital

To determine the prevalence and antimicrobial resistance of enterococci and staphylococci collected from environmental surfaces at a veterinary teaching hospital (VTH). Longitudinal study. Samples collected from surfaces in 5 areas (emergency and critical care, soft tissue and internal medicine, and orthopedic wards; surgery preparation and recovery rooms; and surgery office and operating rooms) of a VTH. Selected surfaces were swabbed every 3 months during the 3-year study period (2007 to 2009). Isolates of enterococci and staphylococci were identified via biochemical tests, and antimicrobial susceptibility was evaluated with a microbroth dilution technique. A subset of isolates was analyzed to assess clonality by use of pulsed-field gel electrophoresis. 430 samples were collected, and isolates of enterococci (n = 75) and staphylococci (110) were identified. Surfaces significantly associated with isolation of Enterococcus spp and Staphylococcus spp included cages and a weight scale. Fourteen Enterococcus spp isolates and 17 Staphylococcus spp isolates were resistant to ≥ 5 antimicrobials. Samples collected from the scale throughout the study suggested an overall increase in antimicrobial resistance of Enterococcus faecium over time. Clonality was detected for E faecium isolates collected from 2 different surfaces on the same day. Although not surprising, the apparent increase in antimicrobial resistance of E faecium was of concern because of the organism's ability to transmit antimicrobial resistance genes to other pathogens. Results reported here may aid in identification of critical control points to help prevent the spread of pathogens in VTHs.

Eight-year Surveillance of Antimicrobial Resistance among Enterococcus Spp. Isolated in the First Bethune Hospital

Abstract This study was to investigate the antimicrobial resistance of Enterococcus spp. isolated in 8 consecutive years in the First Bethune Hospital. Disk diffusion test was used to study the antimicrobial resistance. The data were analyzed by WHONET 5 software according to Clinical and Laboratory Standards Institute (CLSI). Most of 1446 strains of Enterococcus spp. were collected from urine 640 (44.3%), sputum 315 (21.8%), secretions and pus 265 (18.3%) during the past 8 years. The rates of high-level aminoglycoside resistance in Enterococcus faecalis and Enterococcus faecium were 57.4%∼75.9% and 69.0%∼93.8% during the past 8 years, respectively. No Enterococcus spp. was resistant to vancomycin. The antimicrobial resistance of Enterococcus spp. had increased in recent 8 years. The change of the antimicrobial resistance should be investigated in order to direct rational drug usage in the clinic and prevent bacterial strain of drug resistance from being transmitted.

Species distribution and antimicrobial susceptibility of enterococci isolated from broilers infected experimentally with Eimeria spp and fed with diets containing different supplements.

Resistant bacteria in animal can be spread to environment and to humans. Poultry feed and infections caused by Eimeria spp. are important factors in determining the intestinal microbial communities. The aim of this study was to verify the prevalence of species and antimicrobial susceptibility of Enterococcus isolated from broilers fed with different supplements and infected experimentally with Eimeria spp. Broilers were divided in eight groups, fed with diets supplemented with a combination of antimicrobial, ionophore-coccidiostatics, probiotic, essential oil. At 14 days old all birds, except the control, received a solution containing oocysts of Eimeria spp. Samples of cloacal swabs from broilers were collected. A total of 240 Enterococcus sp. strains were isolated, confirmed genus by PCR, classified as species, tested for antimicrobial susceptibility and screened by PCR for the presence of tet(L), tet(M) and erm(B) genes. The overall distribution of species isolated from fecal samples was E. faecalis (40%), followed by E. casseliflavus/E. gallinarum (10.8%), E. mundtii (10.8%), E. faecium (10.8%), E. columbae (5.8%) and E. gallinarum (4.2%). Changes in the composition or frequency of Enterococcus species were observed in all dietary supplementation. Antimicrobial susceptibility tests showed resistance phenotypes a range of antibiotics, especially used in humans such as, streptomycin, penicillin, rifampicin and vancomycin. There was no correlation between different supplementation for broilers and antimicrobial resistance and the presence of tet(M), tet(L) and erm(B) genes. Dietary supplementation had effect on the Enterococcus sp. colonization, but did not have significant effect on the phenotype and genotype of antimicrobial resistance in enterococci.

Prevalence, species distribution and antimicrobial resistance of enterococci isolated from US dairy cattle

To estimate prevalence and antimicrobial susceptibility of enterococci in faeces collected in 2007 from U.S. dairy cattle. A total of 718 faecal samples from 122 dairy cattle operations from 17 US States were collected and cultured for the presence of enterococci. One hundred and eighteen of the 122 operations (96·7%) had at least one dairy cow positive for enterococci and 88·7% (637 of 718) of the faecal samples were positive. At least ten different enterococcal species were found on the dairy operations and 90·7% (107 of 118) of the operations were positive for Enterococcus hirae followed by E. faecalis (40·7%; 48 of 118) and E. faecium (39%; 46 of 118). The highest percentage of resistant isolates were to lincomycin (92·3%; 587 of 636), flavomycin (71·9%; 457 of 636) and tetracycline (24·5%; 156 of 636). Multi-drug resistance (MDR) (resistance ≥ 2 antimicrobials) was observed to as many as seven antimicrobials regardless of class. In contrast to previous studies, faecal shedding of enterococci in dairy cattle occurred in almost 90% of cows sampled and represented a variety of enterococcal species. Although this study demonstrated a high prevalence of antimicrobial-resistant enterococci from dairy cattle faeces in the United States, the contribution of dairy cattle as a source of antimicrobial-resistant enterococci that can be transmitted to humans remains unclear.