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1.
The detection of gelatinase and beta-haemolysis activities was carried out in 83 faecal enterococci (43 Enterococcus faecalis, 33 E. faecium, five E. durans and two E. hirae) of poultry origin. In addition, the presence of genes of the gelE-fsrABC locus and of the cyl operon (cylL(L), cylL(S), cylA, cylB and cylM) were studied by polymerase chain reaction and correlated with gelatinase and beta-haemolysis production, respectively. Most of our E. faecalis isolates were gelatinase-positive (88%), being this activity not frequent in the other enterococcal species (2.5%). Only one of the 33 E. faecium isolates showed a positive gelatinase reaction. All enterococci that showed gelatinase activity harboured the gelE and fsrABC genes, although these genes were also detected in four E. faecalis and one E. durans gelatinase-negative isolates. Most of our non-E. faecalis gelatinase-negative isolates did not harbour gelE-fsrABC genes. A high proportion of faecal enterococci of poultry origin harboured genes of the cyl operon (71%), although only 7% contained the five cyl tested genes (all of them E. faecalis). Only one isolate of our series could express beta-haemolysis, harbouring the whole cyl operon. The cylL(S) genotype was the most prevalent in our enterococci (39%) and also the most prevalent among our E. faecalis isolates (60%). Other genotypes detected were the following ones (% of enterococci): cylA + cylB + cylM (13%), cylL(L) + cylA (4%), cylL(L) (4%), cylL(L) + cylA + cylB + cylM (2%), cylL(L) + cylA + cylM (1%) and cylA + cylM (1%). Both phenotypic and genotypic assays are important to evaluate the virulence potential of enterococci.  相似文献   

2.
Antibiotic susceptibility was tested in 140 non-selected enterococci (73 Enterococcus faecalis, 45 E. faecium and 22 of other species) recovered from faecal samples of 77 wild animals in Portugal. Susceptibility testing for 11 antibiotics (vancomycin, teicoplanin, ampicillin, streptomycin, gentamicin, kanamycin, chloramphenicol, tetracycline, erythromycin, quinupristin-dalfopristin and ciprofloxacin) was determined by disk diffusion and agar dilution methods. Forty-four isolates (31.4%) showed susceptibility to all the antibiotics tested (5.5% of E. faecalis; 62.2% of E. faecium; and 78.6% of E. hirae). Neither ampicillin-resistance nor acquired-vancomycin-resistance was detected and 1.4% of the isolates showed high-level-resistance for gentamicin or streptomycin. Tetracycline and erythromycin resistances were shown in 28.6% and 20.1% of the isolates, respectively. Antibiotic resistance genes were studied by polymerase chain reaction (PCR) and sequencing and tet(M) + tet(L), erm(B) or aac(6')-aph(2') genes were detected in most of tetracycline-, erythromycin- or gentamicin-resistant enterococci respectively. Genes encoding virulence factors were studied by PCR and a wide variety of virulence genes were detected in most of E. faecalis isolates but were rarely found in E. faecium and not detected in the other species. The prevalence of genes encoding virulence factors in E. faecalis was as follows: cpd (98.6%), gelE (75.3%), agg (30.1%), fsr (17.8%), ace (9.6%) and esp (4.1%). Low percentages of antibiotic resistance was found in the faecal enterococci of wild animals but a wide variety of virulence genes were detected among E. faecalis isolates although were rare in the other species.  相似文献   

3.
Antimicrobial activities of 139 Enterococcus isolates (48 E. faecium and 91 E. faecalis) obtained from canine feces, boiler meat samples, swine feces, wild waterfowl feces, and human feces were examined against respective bacteria, including Streptococcus pyogenes, Staphylococcus aureus, Bacillus subtilis, Listeria monocytogenes, Salmonella Enteritidis, and Escherichia coli. Bacteriocin (BAC) production assay revealed that the antimicrobial activity against at least one of 6 indicator strains (BAC+ phenotype) was found in 51 (37%) isolates (29 E. faecium and 22 E. faecalis). Twenty-four of 46 isolates positive for at least one of the enterocin structural genes (entA, entB, entL50AB, and cylL) showed a BAC+ phenotype. The existence of other enterocins or nonenterocin factors was implied because the BAC+ phenotype was detected in a total of 27 Enterococcus isolates that had none of the enterocin genes tested. The antimicrobial activity against Gram-negative strains (Salmonella Enteritidis and E. coli) was detected in the 6 Enterococcus isolates that had either the entA, entB, entL50AB or cylL genes. Moreover, the proportion of the antimicrobial activity against L. monocytogenes among the cylL-positive E. faecalis isolates showing beta-hemolysis (10/16) was significantly (p<0.01) higher than among those lacking beta-hemolysis (2/15). The results suggested that certain characteristics are likely to be associated with the antimicrobial activity against specific organisms.  相似文献   

4.
肠球菌毒力因子研究进展   总被引：1，自引：0，他引：1  
肠球菌(Enterococcus)是人和动物肠道的正常菌群,通常不引起发病,为一种重要的机会致病菌.最近几年,由于免疫制剂的广泛使用,侵入性治疗机会的增加和抗生素的过渡使用,尤其是第3代头孢菌素的广泛应用,使得肠球菌的感染不断上升,成为医院内感染的主要致病菌.肠球菌致病机制与其致病岛编码的毒力因子表面蛋白、溶血素、蛋白明胶酶等有关,肠球菌致病机理不是由单一毒力因子所决定,而是多种毒力因子共同作用的结果.文章综述了肠球菌的各种潜在毒力因子的生物特性及其与致病性的关系,为预防和控制肠球菌感染提供参考.  相似文献   

5.
The objective was to study the prevalence of antimicrobial resistance and the mechanisms implicated in faecal enterococci of wild boars in Portugal. One hundred and thirty-four enterococci (67 E. faecium, 54 E. hirae, 2 E. faecalis, 2 E. durans and 9 Enterococcus spp.) were recovered from 67 wild boars (two isolates/sample), and were further analysed. High percentages of resistance were detected for erythromycin, tetracycline, and ciprofloxacin (48.5%, 44.8%, and 17.9%, respectively), and lower values were observed for high-level-kanamycin, -streptomycin, chloramphenicol, and ampicillin resistance (9%, 6.7%, 4.5%, and 3.7%, respectively). No isolates showed vancomycin or high-level-gentamicin resistance. The erm(B), tet(M), aph(3')-IIIa, and ant(6)-I genes were demonstrated in all erythromycin-, tetracycline-, kanamycin-, and streptomycin-resistant isolates, respectively. Specific genes of Tn916/Tn1545 and Tn5397 transposons were detected in 78% and 47% of our tet(M)-positive enterococci, respectively. The tet(S) and tet(K) genes were detected in one isolate of E. faecium and E. hirae, respectively. Three E. faecium isolates showed quinupristin-dalfopristin resistance and the vat(E) gene was found in all of them showing the erm(B)-vat(E) linkage. Four E. faecium isolates showed ampicillin-resistance and all of them presented seven amino acid substitutions in PBP5 protein (461Q-->K, 470H-->Q, 485M-->A, 496N-->K, 499A-->T, 525E-->D, and 629E-->V), in relation with the reference one; a serine insertion at 466' position was found in three of the isolates. Faecal enterococci from wild boars harbour a variety of antimicrobial resistance mechanisms and could be a reservoir of antimicrobial resistance genes and resistant bacteria that could eventually be transmitted to other animals or even to humans.  相似文献   

6.
Approximately 46% (75/162) or poultry enterococci collected between 1999 and 2000 exhibited high-level resistance to gentamicin (minimum inhibitory concentration [MIC] > or = 500 microg/ml), kanamycin (MIC > or = 500 microg/ml), or streptomycin (MIC > or = 1000 microg/ml). Forty-one percent of the isolates were resistant to kanamycin (n = 67), whereas 23% and 19% were resistant to genramicin (n = 37) and streptomycin (n = 31), respectively. The predominant species identified was Enterococcus faecium (n = 105), followed by Enterococcus faecalis (n = 40) and Enterococcus durans (n = 8). Using polymerase chain reaction, the isolates were examined for the presence of 10 aminoglycoside resistance genes [ant(6)-Ia, ant(9)-Ia, ant(4')-Ia, aph(3')-IIIa, aph(2")-Ib, aph(2")-Ic, aph(2")-Id, aac(6')-Ie-aph(2")-Ia, and aac(6')-Ii]. Five aminoglycoside resistance genes were detected, most frequently aac(6')-Ii and ant(6)-Ia from E. faecium. Seven E. faecalis isolates resistant to gentamicin, kanamycin, or streptomycin were negative for all genes tested, indicating that additional resistance genes may exist. Phylogenetic analysis revealed that the isolates were genetically different with little clonality. These data indicate that enterococci from poultry are diverse and contain potentially unidentified aminoglycoside resistance genes.  相似文献   

7.
Antibiotic resistance in animal isolates of enterococci is of public health concern because of the risk of transfer of antibiotic resistance isolates or resistance determinants to consumers via the food chain. In this study, phenotypic and genotypic resistance in 192 pig isolates of enterococci to ampicillin, avilamycin, avoparcin, bacitracin, flavophospholipol, gentamicin, narasin, tetracycline, tiamulin, tylosin, vancomycin, virginiamycin, copper and zinc were investigated by susceptibility test and molecular methods. Resistance rates varied between the species but all isolates were susceptible to ampicillin, avilamycin, avoparcin, gentamicin and narasin but resistant to tetracycline and tylosin and intermediately resistant to copper. Only Enterococcus gallinarum and Enterococcus casseliflavus were resistant to vancomycin and virginiamycin resistance was present in less than half the Enterococcus faecium isolates. Zinc resistance was largely confined to Enterococcus faecalis but bacitracin resistance was uncommon in E. faecalis in comparison with the other species. Tiamulin resistance was common in all species except E. casseliflavus. Resistance to flavophospholipol was detected in most E. faecium isolates and in a high proportion of E. gallinarum, E. casseliflavus and E. hirae/durans but was only found in one isolate of E. faecalis. No tetO, rplC, rplD, vanA, vanB, vatA and vatD genes were found. The presence of ermB, tetL, tetM, tcrB, aac6-aph2, tetK, tetS, vanC1, vanC2, lsaA, lsaB and vatE varied between the species and largely corresponded to the susceptibility phenotype. The findings show that resistance to antibiotics of high clinical significance for nosocomial Enterococcus infections is absent, whereas antimicrobial resistance was detected for some other antibiotics including bacitracin, flavophospholipol, tetracycline, tiamulin, tylosin and virginiamycin.  相似文献   

8.
The aim of this study was to investigate the prevalence of acquired antimicrobial resistance in the resident intestinal microbiota of cats and to identify significant differences between various cat populations. Escherichia coli, Enterococcus faecalis, E. faecium and Streptococcus canis were isolated as faecal indicator bacteria from rectal swabs of 47 individually owned cats, 47 cattery cats and 18 hospitalised cats, and submitted through antimicrobial sensitivity tests. The results revealed that bacteria isolated from hospitalised and/or cattery cats were more frequently resistant than those from individually owned cats. E. coli isolates from hospitalised cats were particularly resistant to ampicillin, tetracycline and sulfonamide. Both enterococci and streptococci showed high resistance to tetracycline and in somewhat lesser extent to erythromycin and tylosin. Most E. faecium isolates were resistant to lincomycin and penicillin. One E. faecalis as well as one E. faecium isolate from hospitalised cats showed 'high-level resistance' (MIC > 500 microg/ml) against gentamicin, a commonly used antimicrobial agent in case of human enterococcal infections. The results of this research demonstrate that the extent of acquired antimicrobial resistance in the intestinal microbiota of cats depends on the social environment of the investigated population. It is obvious that the flora of healthy cats may act as a reservoir of resistance genes.  相似文献   

9.
The species population of enterococci isolated from four poultry houses for six grow-outs on one farm was determined. Two houses on the farm were control houses and did not use any antimicrobials, while two other houses on the farm used flavomycin, virginiamycin, and bacitracin during different poultry grow-outs. Litter, chick boxliners, feed, and poultry carcass rinses were obtained from each house and cultured for the presence of enterococci. Nine species of enterococci (Enterococcusfaecalis, E. faecium, E. avium, E. casselifiavus, E. cecorum, E. durans, E. gallinarum, E. hirae, and E. malodoratus) were identified from the study. Enterococcus faecalis was isolated more frequently from chick boxliners (n=176; 92%) and carcass rinses (n=491; 69%), whereas E. faecium was found more frequently in litter (n=361; 77%) and feed (n=67; 64%). Enterococcus faecalis (n=763; 52%) and E. faecium (n=578; 39%) were isolated most often from the farm and houses, regardless of antimicrobial treatment. Fifty-two percent of E. faecalis and 39% of E. faecium were isolated from both control (n=389 and 295, respectively) and treatment (n=374 and 283, respectively) samples. This study indicates that antimicrobial usage on this farm did not alter the resident population of enterococci.  相似文献   

10.
The prevalence of strains of Staphylococcus aureus, coagulase-negative (CN) staphylococci, Listeria monocytogenes, Escherichia coli, Enterococcus faecalis, E. faecium and Bacillus cereus, was investigated in 111 bulk milk samples. Staphylococcus aureus was isolated from 38 samples, CN staphylococci from 63 samples, E. coli from 49 samples, E. faecalis or E. faecium from 107 samples, and L. monocytogenes from two samples. Bacillus cereus was not found in any of the samples and three samples were free of any of the selected species. Sensitivity to the anti-microbial drugs amikacin, ampicillin, ampicillin + sulbactam, cephalothin (CLT), cephotaxime, clindamycin, chloramphenicol (CMP), co-trimoxazole, erythromycin (ERY), gentamicin, neomycin, norfloxacin, oxacillin, penicillin, streptomycin (STR), tetracycline (TTC) and vancomycin was tested using the standard dilution technique. Minimum inhibitory concentration (MIC) characteristics (MIC50, MIC90, MIC range) were determined for each microbial species. Resistance against one or more anti-microbial drugs was found in 93% of S. aureus, 40% of CN staphylococci, 73% of E. coli, 88% of E.faecalis, 55% of E.faecium, and one L. monocytogenes strain. Most of the strains, particularly enterococci, were resistant to STR, TTC, and ERY (MIC50 4 microg/ml). A high percentage of staphylococci were resistant to beta-lactam antibiotics. High resistance to CLT was found in 11 strains of E. coli (MIC 256 microg/ml) and strains resistant to CMP (MIC90 16 microg/ml) were detected. The highest numbers of resistance phenotypes were found in E. coil (16) and CN staphylococci (12). Eighteen identical resistance phenotypes were demonstrated in indicator bacteria (E. coli, E. faecalis, E. faecium) and pathogens (S. aureus, CN staphylococci) isolated from the same bulk milk sample. The obtained resistance data were matched against the herd owners' information on therapeutic use of the drugs. This confrontation could not explain the findings of strains resistant to ERY or CMP. Our findings are evidence of selection of resistant strains among not only pathogenic agents, but also among indicator bacteria which can become significant carriers of transmissible resistance genes.  相似文献   

11.
Enterococci are well-known producers of antimicrobial peptides--bacteriocins (enterocins) and the number of characterized enterocins has been significantly increased. Recently, enterocins are of great interest for their potential as biopreservatives in food or feed while research on enterocins as alternative antimicrobials in humans and animals is only at the beginning. The present study provides a survey about the occurrence of enterocin structural genes A, P, B, L50B in a target of 427 strains of Enterococcus faecium (368) and Enterococcus faecalis (59) species from different sources (animal isolates, food and feed) performed by PCR method. Based on our results, 234 strains possessed one or more enterocin structural gene(s). The genes of enterocin P and enterocin A were the most frequently detected structural genes among the PCR positive strains (170 and 155 strains, respectively). Different frequency of the enterocin genes occurrence was detected in strains according to their origin; the strains from horses and silage showed the highest frequency of enterocin genes presence. All possible combinations of the tested genes occurred at least twice except the combination of the gene of enterocin B and L50B which possessed neither strain. The gene of enterocin A was exclusively detected among E. faecium strains, while the gene of enterocin P, B, L50B were detected in strains of both species E. faecium and E. faecalis. In conclusion, a high-frequency and variability of enterocin structural genes exists among enterococci of different origin what offers a big possibility to find effective bacteriocin-producing strains for their application in veterinary medicine.  相似文献   

12.
为研究我国猪源肠球菌的耐药情况,本研究采集18个省市猪养殖场的粪便样品836份进行了肠球菌的分离鉴定,并通过琼脂稀释法测定11种抗菌药物的最小抑菌浓度。结果显示:从836份样品中共分离出225株肠球菌,其中屎肠球菌106株,粪肠球菌56株,小肠肠球菌34株,鹑鸡肠球菌17株,铅黄肠球菌7株,坚忍肠球菌4株,Enterococcus thailandicus 1株。所有的肠球菌对被检抗菌药物耐药程度由高到低依次是四环素(98.2%)、阿米卡星(94.7%)、多西环素(89.3%)、米诺环素(88.9%)、氟苯尼考(88.4%)、红霉素(86.2%)、环丙沙星(63.1%)、氨苄西林(33.8%)、氯霉素(29.8%),未检测到万古霉素和利奈唑胺耐药菌株。除氨苄西林、万古霉素、利奈唑胺外,粪肠球菌对其余8种被检抗菌药物耐药率均高于屎肠球菌。小肠肠球菌对阿米卡星、红霉素、四环素、多西环素、米诺环素5种抗菌药物的耐药率高于屎肠球菌。肠球菌的多重耐药情况集中在6耐、7耐和8耐,占肠球菌总数的72.9%。本研究表明我国猪源肠球菌对常见抗菌药物耐药率较高,应引起更多关注。  相似文献   

13.
We have investigated the resistance of Enterococcus isolated from poultry faeces to antibiotics commonly used as therapy of enterococcal infections. Identification was made by the method of Facklam and Collins. Minimal inhibitory concentrations of penicillin, ampicillin, vancomycin and teicoplanin were determined and high level aminoglycoside resistance was investigated. Genes codifying high level aminoglycoside resistance (HLAR) were determined by PCR. Fifty five Enterococcus strains were isolated (63.6% E. faecalis, 12.7% E. mundtii, 9.1% E. faecium, 7.3% E. casseliflavus, 3.7% E. durans and 3.6% E. hirae). None of the strains were resistant to VAN, TEC, P or AM. HLAR was found in 34.5% of strains for SM, 27.3% for KM and 7.3% for GM. The gene for the bifunctional enzyme was found only in one strain, that showed HLAR to GM and KM. Fourteen strains harboured the gene aph(3')-III, being 11 resistant to KM and STR, and three resistant to GM, KM and STR. The remaining six strains showed HLAR to STR, but were negative for the three genes tested by PCR. The gene ant(4'4") was not detected in any of the strains. No unexpected vancomycin resistance was detected. The resistance rates among poultry strains were lower than those found among human strains isolated from hospital patients in recent Canary studies.  相似文献   

14.
Enterococci are important inhabitants of animal intestine and are widely used in probiotic products. A potentially successful probiotic strain is expected to have several desirable properties in order to be able to exert its beneficial effects. Forty enterococcal isolates from dog faeces were tested for characters believed to be important for probiotic strains; bacteriocin production, resistance or tolerance to antibiotics, low pH, bile tolerance and adhesive activity. The total count of enterococci was found to be 3.3-7.3log(10)CFU/g of faeces. Most identified strains were Enterococcus faecium. All strains were sensitive to vancomycin, ampicillin, penicillin and chloramphenicol. Thirty-three percentage of strains were resistant to erythromycin and 28% to tetracycline. Among 40 isolates, 75% showed a broad inhibitory spectrum only against Gram-positive indicator bacteria. Seven strains with broad bacteriocin activity were selected for further assays. In the presence of 1% bile, the survival rate of selected strains ranged between 72 and 98%. Survival of strains at pH 3.0 was found in the range between 76 and 87% after 3h. The adhesion of the tested strains to intestinal mucus ranged from 4 to 11% for canine mucus and from 5 to 8% for human mucus. E. faecalis EE4 and E. faecium EF01 showed the best probiotic properties. It indicates that they could be used as new candidate probiotic strains after in vivo testing.  相似文献   

15.
The presence of the vanA gene was determined in enterococci from healthy poultry, originating from the Hungarian resistance monitoring system between 2001 and 2004. Enterococci (n = 562) were collected from intestinal samples of slaughtered broiler chickens. The presence of van genes was detected by polymerase chain reaction (PCR). The vancomycin-resistant enterococcus (VRE) strains carried only the vanA gene. Genus- and species-level identification of the vanA gene carrier strains was carried out by PCR using specific primers. In 2001, 25 out of the 289 isolated strains (8.6%) were vanA carriers (1 Enterococcus mundtii, 13 E. durans and 11 E.faecium). In 2002 (n = 87), 20 (23%) strains were vanA positive (11 E. durans and 9 E. faecium). In 2003 and 2004, none of the strains (n = 95 and 91, respectively) were positive for the most common van genes. In 2003, there was only one strain for which higher minimum inhibitory concentrations (MIC) of vancomycin (4 mg/L) and teicoplanin (8 mg/L) were found. In 2004 there were three strains for which the MIC of vancomycin was 8 mg/L, and 2 strains and 1 strain with teicoplanin MICs of 4 mg/L and 8 mg/L, respectively. The potential similarity of these strains was studied by pulsed-field gel electrophoresis (PFGE). The VRE strains were not closely related to one another. The annual data of vancomycin resistance indicate an association between the recovery of vancomycin-resistant enterococci and the use of avoparcin in animal feeds. This study indicates that with the reduced use of antibiotics in food animals, it is possible to decrease the rate of resistant bacteria. Although the use of avoparcin had been banned in 1998, the VRE strains disappeared only five years later.  相似文献   

16.
The prevalence of vancomycin resistant-enterococci (VRE) in faecal samples from cattle, sheep and pigs slaughtered for human consumption was evaluated. Enterococci containing the vanA gene were detected in 25.3% and 2.7% of the porcine and ovine samples, respectively, and were identified as Enterococcus faecium. No vanA-containing enterococcal strains were detected in bovine samples. Enterococcal strains with intrinsic vancomycin resistance were detected in seven (9.9%) faecal samples from pigs and in two samples from both cattle and sheep (3.7% and 2.7%, respectively). All vanA-positive isolates from pigs were resistant to tetracycline and erythromycin, and the mobile element Tn916/Tn1545-like transposon was detected in 90.5% of the tetracycline-resistant isolates that contained the tet(M) gene. Although gelatinase and haemolytic activity were not detected, the hyl and cylB virulence genes were found within the VRE strains isolated.  相似文献   

17.
肠球菌在家蚕消化道中的分布   总被引：4，自引：3，他引：1  
用ＡＰＩ２０ ＳＴＲＥＰ（Ｖ５０） 系统对从健康家蚕消化道来源的８９ 株肠球菌菌株进行数值分类学研究的结果表明：在分离菌株中分布着Ｅｎｔ．ｃａｓｓｅｌｉｆｌａｖｕｓ、Ｅｎｔ．ｆａｅｃａｌｉｓ、Ｅｎｔ．ａｖｉｕｍ 、Ｅｎｔ．ｄｕｒａｎｓ 和Ｅｎｔ．ｇａｌｌｉ ｎａｒｕｍ 等菌种，其分布频率分别为３２６ ％ 、２５９％ 、１５７ ％ 、３４ ％ 和２２ ％ 。其余１８ 个菌株未能被该系统所分类。Ｅｎｔ．ｃａｓｓｅｌｉｆｌａｖｕｓ 和Ｅｎｔ．ｆａｅｃａｌｉｓ 是家蚕消化道内的主要肠球菌菌丛。Ｅｎｔ．ｃａｓｓｅｌｉｆｌａｖｕｓ 在５ 龄初和末的分布频率较高，Ｅｎｔ．ｆａｅｃａｌｉｓ 在５ 龄第４ 和第５ 天的分布频率较高。  相似文献   

18.
The purposes of this study were to determine the phylogenetic background and the virulence gene profiles of Escherichia coli isolates from colisepticemic and feces of healthy (AFEC) broiler chickens. In this study, 253 E. coli isolates including 141 avian pathogenic E. coli (APEC) and 112 AFEC isolates were examined by PCR. In general, 253 E. coli isolates distributed among group A (51.8%), B1 (15.8%), B2 (8.7%), and D (23.7%). Ten (8.9%) AFEC isolates segregated in to B1 phylo-group and 102 (91.1%) isolates fell into six different phylogenetic subgroups. Distribution of colisepticemic and fecal isolates differed significantly in their assignments to A and B1 phylo-groups. The three most prevalent virulence genes were crl, fimH, and aer in isolates between both groups. The four genetic markers aer, papC, afa, and sfa were detected significantly more often among colisepticemic isolates than in fecal isolates from healthy broilers. The presence of stx 2 gene in fecal isolates were significantly differs among the colisepticemic isolates. F17 fimbrial family encoding gene and eae gene were detected in APEC and AFEC isolates, respectively. The colisepticemic and fecal isolates possessed the virulence genes were detected in all of the four phylogenetic groups. Several combination patterns of the virulence genes were detected in APEC and AFEC isolates. In colisepticemic isolates the combination of aer, crl, and fimH genes was the most prevalent pattern. None of the examined isolates harbored the cdt, cnf1, ipaH, and stx 1 virulence gene sequences.  相似文献   

19.
Data on the prevalence of antimicrobial resistant enterococci and staphylococci from the poultry production environment are sparse in the United States. This information is needed for science-based risk assessments of antimicrobial use in animal husbandry and potential public-health consequences. In this study, we assessed the susceptibility of staphylococci and enterococci isolated from poultry litter, recovered from 24 farms across Georgia, to several antimicrobials of veterinary and human health importance. Among the 90 Enterococcus isolates recovered, E. hirae (46%) was the most frequently encountered species, followed by E. faecium (27%), E. gallinarum (12%), and E. faecalis (10%). Antimicrobial resistance was most often observed to tetracycline (96%), followed by clindamycin (90%), quinupristin-dalfopristin (62%), penicillin (53%), erythromycin (50%), nitrofurantoin (49%), and clarithromycin (48%). Among the 110 staphylococci isolates recovered, only coagulase-negative staphylococci (CNS) were identified with the predominant Staphylococcus species being S. sciuri (38%), S. lentus (21%), S. xylosus (14%) and S. simulans (12%). Resistance was less-frequently observed among the Staphylococcus isolates for the majority of antimicrobials tested, as compared with Enterococcus isolates, and was primarily limited to clarithromycin (71%), erythromycin (71%), clindamycin (48%), and tetracycline (38%). Multidrug resistance (MDR) phenotypes were prevalent in both Enterococcus and Staphylococcus; however, Enterococcus exhibited a statistically significant difference in the median number of antimicrobials to which resistance was observed (median = 5.0) compared with Staphylococcus species (median = 3.0). Because resistance to several of these antimicrobials in gram-positive bacteria may be attributed to the shuttling of common drug-resistance genes, we also determined which common antimicrobial-resistance genes were present in both enterococci and staphylococci. The antimicrobial resistance genes vat(D) and erm(B) were present in enterococci, vgaB in staphylococci, and mobile genetic elements Tn916 and pheromone-inducible plasmids were only identified in enterococci. These data suggest that the disparity in antimicrobial-resistance phenotypes and genotypes between enterococci and staphylococci isolated from the same environment is, in part, because of barriers preventing exchange of mobile DNA elements.  相似文献   

20.
粪肠球菌和屎肠球菌是引起猪感染发病的优势肠球菌种,以肠球菌的16S rRNA基因设计属特异性引物,利用SodA基因多态性设计种特异性引物,同时优化反应条件,建立了能同时测定猪源粪肠球菌和屎肠球菌多重PCR方法。通过特异性和敏感性分析,该方法能扩增出肠球菌属特异性片段及粪肠球菌和屎肠球菌种特异性片段;对粪肠球菌敏感性为0...  相似文献   

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