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1.
In vitro antimicrobial susceptibility tests were carried out on 48 strains of Prototheca zopfii, an achlorophyllous algae causing refractory mastitis in dairy cows; 27 antimicrobials were evaluated. All strains were susceptible to both myxin and nystatin. In addition, 22 strains were susceptible to amphotericin B, 21 to polymyxin B, and 18 to gentamicin. Only 1 strain was susceptible to kanamycin. All strains were resistant to ampicillin, bacitracin, carbenicillin, cephalothin, chloramphenicol, clotrimazole, cloxacillin, erythromycin, flucytosine, ketoconazole, lincomycin, miconazole, neomycin, nitrofurazone, novobiocin, oleandomycin, penicillin, rifampin, streptomycin, tetracycline, and vancomycin.  相似文献   

2.
Minimal concentrations of penicillin, ampicillin, cephalothin, chloramphenicol, tetracycline, erythromycin, nitrofurantoin, kanamycin and gentamicin inhibitory to Pasteurella haemolytica biotypes A and T were determined. They were found to be significantly higher for T than for A type strains in the case of all the antimicrobial drugs tested except the two aminoglycosides kanamycin and gentamicin, for which no differences were observed. In the case of penicillin the differences were so marked that they may be useful as a basis for biotyping P haemolytica isolates. The emergence of antibiotic-resistant strains observed in recent years, however, may limit such application.  相似文献   

3.
The susceptibility to antimicrobials of bacterial species most frequently isolated from companion animals in a veterinary teaching diagnostic laboratory was evaluated retrospectively. A significant decrease between 1990-1992 and 2002-2003 was noted in the susceptibility of dog isolates to the following antimicrobials: Escherichia coli to cephalothin (86% to 61%, P < 0.001); E. coli to ampicillin (85% to 67%, P < 0.001); Proteus spp. to ampicillin (92% to 71%, P < 0.01); coagulase-positive staphylococci (Staphylococcus aureus and Staphylococcus intermedius) to enrofloxacin (99% to 95%, P < 0.01). Significantly increased susceptibilities were also noted as follows: coagulase-positive staphylococci to erythromycin (78% to 90%, P < 0.001) and tetracycline (61% to 77%, P < 0.001). Despite a limited number of results available for cats, a significant increase in susceptibility was noted for Pseudomonas spp. to gentamicin (40% to 100%, P < 0.05) and for E. coli to tetracycline (59% to 80%, P < 0.05). Regular updates on the resistance to antimicrobials used in veterinary medicine are required.  相似文献   

4.
Factors associated with the carriage of antimicrobial-resistant Escherichia coli isolates were analysed among zoo animals. An association was observed between selection of amoxicillin as the first-line therapy and a significantly higher percentage of resistance to ampicillin (54.5%) from 11 animals treated with antimicrobials, compared with isolates from 32 untreated animals (9.4%). In addition, the percentage resistance to kanamycin (36.4%), gentamicin (27.3%), trimethoprim (27.3%) and tetracycline (63.6%) from 11 treated animals was significantly higher than those from 32 untreated animals (3.1%, 3.1%, 3.1% and 25%, respectively), although these antimicrobials were rarely used. All kanamycin-, gentamicin- and trimethoprim-resistant isolates and more than half of the tetracycline-resistant isolates from treated animals were also resistant to ampicillin. Co-resistance to other antimicrobials with ampicillin was suggested to contribute to an increasing of resistance towards antimicrobials that were rarely administered. The present investigation revealed an association of antimicrobial treatment with the spread of antimicrobial-resistant bacteria among zoo animals.  相似文献   

5.
The minimal inhibitory concentrations of penicillin G, ampicillin, gentamicin, erythromycin and rifampicin were determined for nine strains of Corynebacterium equi. The effect of combinations of any two of these antibiotics on the killing of these strains was determined at antibiotic concentrations achievable in horses using recommended drug dosages (ampicillin 4.0 μg/ml, gentamicin 1.0 μg/ml and erythromycin 0.25 μg/ml). Penicillin G was used at 4.0 μg/ml and rifampicin at 0.063 μg/ml. The combinations of gentamicin with erythromycin or rifampicin gave antagonistic effects on killing compared to either drug alone. Combinations of erythromycin with rifampicin or penicillin showed synergistic effects, as did penicillin-gentamicin. All other combinations, and a triple combination of penicillin-rifampicin-erythromycin, showed additive effects only.  相似文献   

6.
Forty-four isolates of Bacillus anthracis made from carcasses and soil in different localities of an endemic anthrax area in the Kruger National Park, South Africa, were tested by standard disc diffusion for their susceptibility to 18 different antibiotics. These were ampicillin, penicillin G, sulphatriad, streptomycin, clindamycin, gentamicin, fusidic acid, trimethoprim, sulphamethoxazole, chloramphenicol, erythromycin, methicillin, tetracycline (2 different concentrations), novobiocin, cefotaxime, netilmicin, cefamandole and cefoxitin. All the isolates were susceptible to ampicillin, streptomycin, chloramphenicol, erythromycin, tetracycline, methicillin and netilmicin. More than 90% of the isolates were sensitive to clindamycin, gentamicin and cefoxitin, whereas only 84.1% of the isolates were sensitive to penicillin G, 86.4% to novobiocin and 68.18% to cefamandole. Complete resistance in 100% of the isolates was encountered with trimethoprim and sulphamethoxazole, with 95.45% for sulphatriad. Moderate sensitivity occurred with penicillin G (15.9% of the isolates), clindamycin (6.8%), novobiocin (13.6%), fusidic acid (84.1%), cefotaxime (100%), cefamandole (31.8%) and cefoxitin (6.8%). The relevance of the findings to the therapeutic uses of different types of antibiotic in human clinical cases referred to in the literature is discussed.  相似文献   

7.
通过细菌形态学和细菌生化特性,分离和鉴定了新疆地区患子宫内膜炎的21头奶牛子宫分泌物中的病原菌分别为蜡样芽孢杆菌(24.5%)、非溶血性链球菌(18.4%)、大肠杆菌(14.3%)、溶血性链球菌(10.2%)、表皮葡萄球菌(10.2%)、金黄色葡萄球菌(10.2%)、胎儿弯曲菌(10.2%)和不动杆菌等.其中革兰氏阳性菌检出率较高(73.5%).子宫内膜炎病原菌以单一菌株感染为主(47.6%).采用Kirby-Barer法测定了鉴定菌株对13种抗微生物药的体外药物敏感性.链球菌、大肠杆菌和葡萄球菌对氨苄西林不敏感,而对卡那霉素和庆大霉素敏感性较高;大肠杆菌对青霉素和氨苄西林全部耐药(100%),对四环素和多西环素耐药率较高(均为83.3%);溶血性链球菌对青霉素和四环素全部耐药,对链霉素耐药率为80%;相对而言,表皮葡萄球菌和金黄色葡萄球菌的耐药率较低;氟喹诺酮类对各种分离菌株比较敏感.  相似文献   

8.
张晓梅 《饲料工业》2012,33(5):26-30
为了解鲜牛奶中细菌的分布情况及其对抗生素的敏感状况,实验对30份采自河北张家口地区某养殖场的新鲜无菌牛奶进行细菌分离鉴定,并分别用青霉素(16μg/ml)、氯霉素(32μg/ml)、克林霉素(4μg/ml)、红霉素(8μg/ml)、四环素(16μg/ml)、庆大霉素(16μg/ml)、环丙沙星(4μg/ml)、头孢噻吩(32μg/m)l进行药敏实验。结果显示30份牛奶样品中共分离得到111株菌,分别为葡萄球菌31株、沙雷氏菌14株、假单胞菌12株、芽孢杆菌11株、肠杆菌5株、不动杆菌4株、奇异变形杆菌3株、微球菌3株、巨球菌3株、肠球菌4株、其它菌21株。其中耐青霉素16μg/ml的为50株,耐氯霉素32μg/ml的为23株,耐克林霉素4μg/ml的为46株,耐红霉素8μg/ml的为37株,耐四环素16μg/ml的为38株,耐庆大霉素16μg/ml的是7株,耐环丙沙星4μg/ml的为8株,耐头孢噻吩32μg/ml的为40株。通过实验可知,细菌类型主要有葡萄球菌、沙雷氏菌、假单胞菌等;8种抗生素中,庆大霉素、环丙沙星、氯霉素的抑菌效果较好,而青霉素、克林霉素、红霉素、四环素、头孢噻吩的抑菌效果相对较差。  相似文献   

9.
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   

10.
Minimum inhibition concentrations (MICs) were determined for ampicillin, ceftiofur, cephalothin, chloramphenicol, enrofloxacin, gentamicin, lincomycin, lincospectin (lincomycin/spectinomycin), neomycin, premafloxacin, spectinomycin, sulfamethoxazole/trimethoprim, and tetracycline against a total of 180 isolates of Actinobacillus pleuropneumoniae, Escherichia coli, and Salmonella choleraesuis (60 each) clinically isolated from pigs on farms in Taiwan from 1994 to 1996. No more than 3 isolates per farm were used. Ceftiofur had the highest activity in vitro against isolates of A. pleuropneumoniae, E. coli, and S. choleraesuis, with MIC90 values of 0.03, 2, and 1 microg/ml, respectively. Premafloxacin was highly active against isolates of A. pleuropneumoniae, E. coli, and S. choleraesuis, with MIC90 values of 2, 8, and 0.5 microg/ml, respectively, which were lower than those with enrofloxacin (MIC90 8, 32, and 2 microg/ml, respectively). Neomycin was moderately active against A. pleuropneumoniae and E. coli, with MIC90 values of 8 and 64 microg/ml, respectively, but was inactive with S. choleraesuis. Gentamicin showed high activity against A. pleuropneumoniae (MIC90 of 2 microg/ml) but was only moderately active with E. coli and S. choleraesuis (MIC90 of 64 and 32 microg/ml). Cephalothin was highly active against isolates of A. pleuropneumoniae (MIC90 of 1 microg/ml) but was inactive with E. coli (MIC90 of 128 microg/ml). Lincomycin had moderate activity (MIC90 of 32 microg/ml) against A. pleuropneumoniae. Chloramphenicol, lincomycin, and tetracycline were inactive with E. coli and S. choleraesuis (MIC90 > 128 microg/ml). In conclusion, ceftiofur and premafloxacin were highly active against isolates of A. pleuropneumoniae, E. coli, and S. choleraesuis, enrofloxacin and gentamicin were highly to moderately active; cephalothin was highly active against A. pleuropneumoniae and moderately active against S. cholearesuis; chloramphenicol, lincomycin, and tetracycline were active only with A. pleuropneumoniae; neomycin was moderately active against A. pleuropneumoniae and E. coli. The other antimicrobials tested were inactive.  相似文献   

11.
This study assessed the associations between antimicrobial use and other management practices in pigs and antimicrobial resistance in generic Escherichia coli recovered from feces of weaner and finisher pigs on 39 purposefully selected farrow-to-finish farms in Ontario and 8 in British Columbia. Antimicrobials (n = 13), most frequently penicillins and tetracycline, wer dministered to different age groups of pigs on study farms through various routes of administration. Logistic regression was used to model risk factors to antimicrobial resistance in fecal E. coli of pigs for the following antimicrobials: ampicillin, apramycin, carbadox, cephalothin, chloramphenicol, kanamycin, neomycin, nitrofurantoin, spectinomycin, streptomycin, sulfamethoxazole tetracycline, and cotrimoxazole (trimethoprim and sulfamethoxazole). Use of antimicrobials in weaner pigs compared with use in finisher pigs was associated with resistance in most models. There was phenotypic evidence of different mechanisms of resistance selection, including direct selection [use of carbadox was associated with carbadox resistance (OR = 6.48)]; cross-resistance [use of spectinomycin was associated with streptomycin resistance (OR = 2.29)]; and possible co-selection [ceftiofu use was associated with tetracycline resistance (OR = 6.12)]. These results provide further evidence that use of antimicrobials in pigs selects for resistance among fecal E. coli within and between classes of antimicrobials.  相似文献   

12.
The in vitro susceptibilities of 50 field isolates of Riemerella anatipestifer from ducks to ceftiofur and 16 other commonly used antimicrobials were determined. The MIC90 values (MIC refers to minimum inhibitory concentrations) for the antimicrobials used in this study are as follows: penicillin was 16 microg/ml; ceftiofur was 32 microg/ml; cephalothin, chloramphenicol, flumequine, and kanamycin were 64 microg/ml; nalidixic acid, nitrofurantoin, and sulfamethoxazole were 128 microg/ml; amikacin, ampicillin, gentamicin, lincomycin, spectinomycin, streptomycin, tetracycline, and trimethoprim were > or = 256 microg/ml. The therapeutic efficacy of ceftiofur against a highly lethal experimental R. anatipestifer infection in ducks was also evaluated. All experimental ducks were infected through the infraorbital sinus with 1 ml of 9 x 10(9) CFU of R. anatipestifer. Ceftiofur (0, 0.25, 0.5, 1, and 2 mg/kg) was injected subcutaneously 5 hours after infection. A single dose of 2 mg/kg resulted in 73% survival as compared with 10% survival in the infected, but untreated controls.  相似文献   

13.
Pseudomonas mallei was isolated from pus samples obtained from 34 mallein-positive horses. The isolates were subjected to in vitro sensitivity test using 16 different antimicrobial discs. All isolates (34) were sensitive to sulfamethizole, gentamycin, tetracycline, sulfathiazole, kanamycin, tobramycin, streptomycin and a combination of trimethoprim and sulfamethoxazole while none of them were sensitive to cephalothin, colistin, ampicillin, penicillin and nitrofurantoin. Rifapicin, chloramphenicol and carbenicillin were effective against 32, 26 and 18 isolates respectively. The minimum inhibitory concentrations (MICs) of gentamycin, tetracycline, tobramycin, sulfamethizole, streptomycin, rifampicin and a combination of trimethoprim and sulfamethoxazole were 0.28, 0.38, 0.67, 1.40, 3.40, 5.86 and 5.30 micrograms/ml, respectively.  相似文献   

14.
猪链球菌Ⅱ型四川分离株对抗菌药的敏感性分析   总被引：6，自引：1，他引：6  
对四川省不同地区链球菌病病死猪体内分离的7株链球菌Ⅱ型进行抗菌药敏感性试验,用链球菌兰氏D群C55914作为对照,比对菌为肺炎链球菌质控菌株ATCC49619.在32种抗菌药中,选择29种药物进行纸片法药敏试验.试验结果表明:7株链球菌耐药谱非常相似,对青霉素、氨苄西林、阿莫西林、奥格门丁、卡那霉素、红霉素、壮观霉素、氯霉素、氟苯尼考、头孢氨苄、头孢拉定、头孢他定、头孢呋辛、头孢曲松、环丙沙星、氧氟沙星、二氟沙星、沙拉沙星、达氟沙星、恩诺沙星、复方新诺明、万古霉素、亚安培南均敏感;对阿米卡星、新霉素、庆大霉素3株敏感,4株中敏;对四环素和多西环素2株中敏,5株耐药;对链霉素1株中敏,6株耐药.用21种药物进行最小抑菌浓度(MIC)测定,结果7株均对青霉素、氨苄西林、卡那霉素、红霉素、头孢他定、头孢呋辛、头孢曲松、头孢噻呋、环丙沙星、达氟沙星、氧氟沙星、二氟沙星、沙拉沙星、恩诺沙星、磺胺六甲氧嘧啶敏感,1株对新霉素和阿米卡星中敏,2株耐药;所有菌株对四环素、土霉素、多西环素、链霉素均耐药.两种方法总体结果一致.  相似文献   

15.
M Y Lin 《Avian diseases》1987,31(4):705-712
Twenty-nine antibiotics or drugs were incorporated individually into mycoplasma agar to evaluate their inhibitory activity against avian mycoplasmas: 100 recent Taiwan isolates of 7 serotypes and 10 standard strains of 7 serotypes were tested. All of the standard strains were very sensitive to erythromycin, chlorotetracycline, doxycycline, minocycline, and tetracycline, but the local isolates were highly resistant to these antibiotics. The drugs or antibiotics that possessed an MIC90 of 50 micrograms/ml or less against the local isolates were tiamulin (less than 0.4 micrograms/ml), lincospectin (2.7), josamycin (2.7), lincomycin (3.0), spectinomycin (4.8), tylosin (6.0), kanamycin (6.0), chloramphenicol (6.0), gentamicin (7.5), apramycin (24.5), doxycycline (27.4), minocycline (29.0), spiramycin (30.0), colistin (44.3), leucomycin (45.0), and streptomycin (50.0). The MIC90 of the other antibiotics or drugs was greater than 50 micrograms/ml. None of the isolates or strains were sensitive to nalidixic acid, ronidazole, penicillin, ampicillin, cephalexin, carbadox, or four sulfa drugs at a concentration about 5 times the therapeutic level.  相似文献   

16.
宠物源大肠埃希菌的分离鉴定和耐药性研究   总被引：1，自引：0，他引：1  
为调查长春地区宠物源大肠埃希菌耐药流行情况,从2家宠物医院采集135份宠物肛拭子样品,分离和鉴定大肠埃希菌并进行多重PCR分群。测定大肠埃希菌分离株对19种抗菌药物的耐药性,并鉴定超广谱β-内酰胺酶(ESBLs)表型。共分离鉴定获得95株宠物源大肠埃希菌,它们对氨苄西林和哌拉西林的耐药率最高(78.9%和76.8%);其次是四环素(61.6%);对头孢唑林、头孢噻肟、头孢吡肟、庆大霉素、复方新诺明、环丙沙星和左氧氟沙星的耐药率均超过了50%;所有分离株均对亚胺培南和美罗培南敏感。其中15个分离株对受试的抗菌药物全部敏感(15.8%),63株呈多重耐药表型(66.3%)。ESBLs型菌株占53.7%。本研究探明了长春地区宠物源大肠埃希菌的耐药流行情况,对宠物临床上用药具有指导价值。  相似文献   

17.
The study objective was to describe and evaluate antimicrobial resistance profiles in Salmonella isolated from Alberta swine finishing farms. Salmonella isolates (n = 322) were obtained from 192 fecal and 84 environmental samples of the 60 Salmonella-positive swine finishing farms. Isolates were classified susceptible, intermediate or resistant based on NCCLS guidelines. More than half of the isolates (53.4%) were susceptible to all of the 18 antimicrobials in the testing panel. No resistance was observed to amikacin, amoxicillin/clavulanic acid, cefoxitin, ceftiofur, ceftriaxone, cephalothin, ciprofloxacin, imipenem or nalidixic acid. Less than 1% of isolates were resistant to apramycin, gentamicin and trimethoprim/sulfamethoxazole. Higher frequencies of resistance were observed for chloramphenicol (4.7%), ampicillin (7.8%), kanamycin (11.8%), sulfamethoxazole (21.1%), streptomycin (25.5%) and tetracycline (38.8%). Eleven Salmonella serovars had isolates with resistance to > or =3 antimicrobials. The most frequently resistant serovar was Salmonella Derby, with 27 (38.0%) isolates resistant to > or =3 antimicrobials, including resistance to five and six antimicrobials. An absence of resistance to cephalosporins and fluoroquniolones and a low proportion of isolates resistant to amikacin, amoxicillin/clavulanic acid, apramycin, gentamicin and trimethoprim/sulfamethoxazole are encouraging findings from public health and animal health perspectives. Frequent resistance observed for ampicillin, kanamycin, sulfamethoxazole, streptomycin and tetracycline, antimicrobials commonly used in veterinary medicine for decades, indicates an urgent need to utilize these antimicrobials more prudently if their benefits are to be preserved.  相似文献   

18.
One hundred Staphylococcus aureus strains from bovine mastitis were tested for susceptibility to eight antimicrobials by the paper disc diffusion method (Kirby-Bauer) and a commercially prepared dilution system. Except in the case of penicillin and possibly ampicillin, comparison of the two methods showed excellent correlation. Agreement was perfect with methicillin, chloramphenicol, gentamicin, and kanamycin.  相似文献   

19.
The in vitro activities of 15 antimicrobial agents against 195 strains of Escherichia coli isolated from dairy calves affected by neonatal diarrhoea were determined. Of these strains 137 produced one or more potential virulence factors (F5, F41, F17, cytotoxic necrotizing factor, verotoxin and the eae gene), but the remaining 58 strains did not produce any of these factors. The overall percentage of resistant strains to streptomycin, tylosin and tetracycline was very high (above 65%). A high level of resistance (from 23 to 50%) to ampicillin, neomycin, kanamycin, spectinomycin, chloramphenicol, sulphadimethoxine and trimethoprim was also detected. The E. coli strains were very susceptible (89-95%) to apramycin and gentamicin and highly susceptible (99-100%) to polymyxin B, florfenicol and nitrofurazone. Some significant differences (P < 0.05) in the frequencies of resistance to some of the antimicrobials tested and in the rates of multi-drug resistance among the strains producing potential virulence factors and non-fimbriated, non-toxigenic, eae-negative strains were found. Most of the strains showed multi-resistance: 76.9% of the isolates were resistant to at least two antibiotics, 67.7% were resistant to at least four antibiotics and 50.3% were resistant to at least six antibiotics.  相似文献   

20.
Prevalence and characterization of Staphylococcus aureus in young goats   总被引：2，自引：0，他引：2  
Thirty-six Staphylococcus aureus isolates recovered from 35 of 204 young goats at slaughter were characterized. All isolates were susceptible to cephalothin, clindamycin, chloramphenicol, gentamicin, kanamycin, and amikacin. All but 2 were susceptible to erythromycin and tetracycline, and 19 and 20 were susceptible to penicillin and ampicillin, respectively. Thirteen isolates were classified as biotype A, 9 isolates were classified as biotype B, 8 isolates were classified as biotype C, and 6 isolates were classified as intermediate between B and C or were not biotypable. Six biotype A isolates were enterotoxigenic; 4 produced enterotoxin B, 1 produced enterotoxin C, and 1 produced enterotoxin D. Two biotype B strains produced enterotoxin B, and all 8 biotype C isolates produced enterotoxin C and the toxic shock syndrome toxin-1.  相似文献   

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