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1.
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2.
A total of 92 canine/feline Pasteurella multocida strains form respiratory tract infections or infections of skin/ear/mouth as well as 42 canine/feline Bordetella bronchiseptica strains from respiratory tract infections were investigated for their susceptibility to antimicrobial agents. While the P. multocida strains were susceptible to all antimicrobial agents tested - except sulfonamides -, a considerable number of the B. bronchiseptica strains was resistant or exhibited high MIC values against a number of antimicrobial agents including penicillin G, oxacillin, cefazolin, ceftiofur, cefquinome, sulfamethoxazole, and trimethoprim/sulfamethoxazole.  相似文献   

3.
Phenotypic resistance of veterinary pathogens to more than one antimicrobial agent (multi-resistance) may be caused by intrinsic resistance to the antimicrobial agents, acquired cross-resistance, or acquired co-resistance. Known cross-resistances allow to select so-called "representative substances" which are tested and the results of which can also be regarded as being valid for other members of the same class of antimicrobial agents. In general, a limitation in the number of antimicrobial agents to be tested in routine diagnostics is necessary because of capacity and cost efficiency. This is of particular relevance when the broth microdilution method - recommended as the method of choice - with 96-well microtiter plates is used. The knowledge about the relationship between different resistance phenotypes and the corresponding resistance mechanisms is of major value for both, the laboratory personnel and the veterinary practitioner. This review explains how "representative substances" for the most relevant classes of antimicrobial agents used in veterinary medicine are chosen on the basis of known cross-resistances.  相似文献   

4.
Bacteria with antimicrobial resistance can be transferred from animals to humans and may compromise antimicrobial treatment in case of infection. To determine the antimicrobial resistance situation in bacteria from Swiss veal calves, faecal samples from 500 randomly selected calves originating from 129 farms were collected at four big slaughterhouses. Samples were cultured for Escherichia coli, Enterococcus sp. and Campylobacter sp. and isolated strains were tested for antimicrobial susceptibility to selected antimicrobial agents by the minimal inhibitory concentration technique using the broth microdilution method. From 100 farms, data on farm management, animal husbandry and antimicrobial treatments of the calves were collected by questionnaire. Risk factors associated with antimicrobial resistance were identified by logistic regression. In total, 467 E. coli, 413 Enterococcus sp. and 202 Campylobacter sp. were isolated. Of those, 68.7%, 98.7% and 67.8%, respectively, were resistant to at least one of the tested antimicrobial agents. Resistance was mainly observed to antimicrobials frequently used in farm animals. Prevalence of resistance to antimicrobials important for human treatment was generally low. However, a rather high number of quinupristin/dalfopristin-resistant Enterococcus faecium and ciprofloxacin-resistant Campylobacter sp. were detected. External calf purchase, large finishing groups, feeding of milk by-products and administration of antimicrobials through feed upon arrival of the animals on the farm significantly increased the risk of antimicrobial resistance at farm level. Participation in a quality assurance programme and injection of a macrolide upon arrival of the animals on the farm had a protective effect. The present study showed that veal calves may serve as a reservoir for resistant bacteria. To ensure food safety, veal calves should be included in the national monitoring programme for antimicrobial resistance in farm animals. By improving farm management and calf husbandry the prevalence of resistance may be reduced.  相似文献   

5.
OBJECTIVE: To determine and compare levels and patterns of antimicrobial resistance among Escherichia coli isolated from pigs on farms that did not use antimicrobial agents versus pigs produced under conventional methods. DESIGN: Cross-sectional study. Sample Population-35 antimicrobial-free and 60 conventional swine farms. PROCEDURES: Farms were visited once, and fecal samples were collected from 15 finisher pigs if available. One E coli isolate from each sample was tested for susceptibility pattern to 14 antimicrobial agents by use of microbroth dilution. RESULTS: E coli isolates were recovered from 1,381 (97.1%) of 1,422 fecal samples. Herd size was significantly larger for conventional swine farms. Resistance to ceftriaxone, ciprofloxacin, or nalidixic acid was not observed on any of the 95 farms. Three isolates from 2 conventional farms were resistant to ceftiofur. Conventional farms had significantly higher levels of resistance to ampicillin, sulfamethoxazole, tetracycline, and chloramphenicol, compared with antimicrobial-free farms. Fourteen percent of E coli isolates were susceptible or had intermediate resistance to all the tested antimicrobial agents. The 3 most frequent patterns of multiple resistance were streptomycin-tetracycline, sulfamethoxazole-tetracycline, and kanamycin-streptomycin-sulfamethoxazole-tetracycline. CONCLUSIONS AND CLINICAL RELEVANCE: Cessation of antimicrobial use did not appear to result in an immediate reduction in antimicrobial resistance in swine farms. Prospective studies of long-term antimicrobial usage and cessation are needed to estimate the extent to which food animal production may be contributing to antimicrobial drug resistance and might provide a direct measure of the rates of reversibility of antimicrobial drug resistance that might be achieved by curtailing antimicrobial usage.  相似文献   

6.
Large amounts of antimicrobial agents are in the production of food animals used for therapy and prophylactics of bacterial infections and in feed to promote growth. The use of antimicrobial agents causes problems in the therapy of infections through the selection for resistance among bacteria pathogenic for animals or humans. Current knowledge regarding the occurrence of antimicrobial resistance in food animals, the quantitative impact of the use of different antimicrobial agents on selection for resistance and the most appropriate treatment regimes to limit the development of resistance is incomplete. Programmes monitoring the occurrence and development of resistance are essential to determine the most important areas for intervention and to monitor the effects of interventions. When designing a monitoring programme it is important to decide on the purpose of the programme. Thus, there are major differences between programmes designed to detect changes in a national population, individual herds or groups of animals. In addition, programmes have to be designed differently according to whether the aim is to determine changes in resistance for all antimicrobial agents or only the antimicrobial agents considered most important in relation to treatment of humans. In 1995 a continuous surveillance for antimicrobial resistance among bacteria isolated from food animals was established in Denmark. Three categories of bacteria, indicator bacteria, zoonotic bacteria and animal pathogens are continuously isolated from broilers, cattle and pigs and tested for susceptibility to antimicrobial agents used for therapy and growth promotion by disc diffusion or minimal inhibitory concentration determinations. This programme will only detect changes on a national level. However, isolating the bacteria and testing for several antimicrobial agents will enable us to determine the effect of linkage of resistance. Since 1995 major differences in the consumption pattern of different antimicrobial agents have occurred in Denmark. The Danish monitoring programme has enabled us to determine the effect of these changes on the occurrence of resistance. The Danish monitoring is, however, not suited to determine changes on a herd level or to detect emergence of new types of resistance only occurring at a low level.  相似文献   

7.
OBJECTIVE: To determine whether duration of hospitalization in the intensive care unit (ICU) of a veterinary teaching hospital was associated with prevalence of antimicrobial resistance among rectal Escherichia coli isolates from dogs, whether antimicrobial treatment was associated with prevalence of antimicrobial resistance, and whether there were associations among antimicrobial drugs to which isolates were resistant. DESIGN: Prospective observational study. ANIMALS: 116 dogs hospitalized in an ICU for >or= 3 days. PROCEDURES: Rectal swab specimens were obtained every 3 days and submitted for bacterial culture for E coli. Isolates were tested for susceptibility to 12 antimicrobial agents by means of disk diffusion. RESULTS: For each additional day that a dog was hospitalized in the ICU, the odds of being colonized with an E coli isolate resistant to 1 or more of the 12 antimicrobials tested increased by a factor of 1.5, independent of antimicrobial treatment. Dogs that were treated with enrofloxacin were 25.6 times as likely to be colonized by a quinolone-resistant E coli strain as were dogs that did not receive any antimicrobials. Significant correlations were found for resistance to agents in the extended-spectrum cephalosporin group and the quinolone group. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that the proportion of rectal E coli isolates obtained from dogs housed for >or= 3 days in a veterinary teaching hospital ICU that were resistant to antimicrobial agents increased as the duration of hospitalization in the ICU increased. Thus, ICU hospitalization time should be as short as possible to prevent development of antimicrobial resistance among rectal E coli isolates.  相似文献   

8.
One hundred and eighteen isolates of Pseudomonas aeruginosa obtained from clinical material were tested for susceptibility to antimicrobial agents. Regardless of species of animal from which the isolate was obtained, 75% of the isolates were inhibited by ≤ 4 μg of gentamicin/ml, 100% by ≤ 4 μg of tobramycin/ml, 97% by ≤ 128 μg of carbenicillin/ml, and 2% by ≤ 64 μg of chloramphenicol/ml.  相似文献   

9.
为了摸清上海和河北地区奶牛乳房炎的主要致病菌克雷伯菌的分离率及其耐药情况,对采集自上海和河北两地的乳房炎患病奶牛乳样进行克雷伯菌的分离培养和形态学、分子生物学鉴定,并选择临床常用的抗生素对分离得到的克雷伯菌进行药敏试验。经革兰染色、镜检以及分子生物学鉴定发现,采集自上海地区的100份乳房炎患病奶牛乳样中有18份乳样存在克雷伯菌,分离率为18%;采集自河北地区的100份乳房炎患病奶牛乳样中有14份乳样存在克雷伯菌,分离率为14%;且上海和河北地区2017年下半年乳房炎患病奶牛乳样中克雷伯菌分离率均高于上半年。药敏试验结果表明,该试验分离得到的克雷伯菌对所测试的抗生素存在不同程度的耐药性,其中,单一耐药菌株占21.88%,多重耐药菌株占53.13%,全部敏感的菌株占12.50%。由该试验结果可以得出,上海、河北地区奶牛发生的乳房炎是与克雷伯菌感染有关;且分离得到的克雷伯菌对临床常用的抗生素存在不同程度的耐药性。在动物生产和兽医临床上应及时监控克雷伯菌的流行趋势和耐药性变迁,并合理使用抗生素以减少耐药菌株的产生。  相似文献   

10.
A number of 689 Streptococcus suis isolates collected nationwide from diseased and healthy pigs from 1987 to 1996 were surveyed for antibiotic susceptibilities to 11 drugs. No isolates resistant to amoxicillin, chloramphenicol, and sulfamethoxazole/trimethoprim were found. Isolates were highly susceptible to penicillins (penicillin G, ampicillin, and amoxicillin) except cloxacillin. They were not susceptible to tetracycline, streptomycin, and kanamaycin (MIC90 50 microg/ml, > or = 100 microg/ml, and > or = 100 microg/ml, respectively). Multiple-resistant isolates (> or = 3 antimicrobial agents) were found in 20.3% of all isolates tested.  相似文献   

11.
A survey was conducted in which 15 laboratories involved in avian bacteriology tested the antimicrobial sensitivity of cultures of Staphylococcus aureus, S. epidermidis, Escherichia coli, Alcaligenes faecalis and Salmonella typhimurium, using the disc diffusion test as routinely practised in each laboratory. Up to 28 different antimicrobials or antimicrobial combinations were used. The most commonly tested agents were ampicillin, benzylpenicillin, chloramphenicol, erythromycin, furazolidone, neomycin, streptomycin, sulphonamide, tetracycline and trimethoprim/sulphonamide. Results between laboratories were compared according to the width of the zone of inhibition (annular radius) where 5 or more laboratories used the same disc content of a particular antimicrobial agent, and on whether a culture was interpreted as being sensitive or resistant to a particular agent. The variation in annular radii about the mean values were less than +/- 2 SD in 39.5% and greater than +/- 3 SD in 32.6% of 43 different antimicrobial/culture combinations involving 8 different agents. The range of annular radii measurements was greatest with trimethoprim/sulphonamide and streptomycin discs and with the S. epidermidis culture. Variation in the interpretation of test results was greatest with the Gram-negative bacteria, where for each of the more frequently tested agents at least one, commonly 2 and sometimes all 3 cultures were reported as sensitive and resistant to the same agent by different laboratories. The calibrated dichotomous sensitivity (CDS) test of Bell (1975, 1984) was evaluated as a standardised disc diffusion procedure and was found to be reproducible and accurate. Results obtained using antimicrobial agents calibrated for use in the CDS test were compared with results obtained in the survey using the same agents or agents showing identical resistance patterns.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

12.
To determine the current status of antimicrobial susceptibility of bacterial pathogens from animals in Germany, the Bff-GermVet monitoring program was initiated as a complementary program to the German national monitoring program GERM-Vet conducted by the Federal Office of Consumer Protection and Food Safety (BVL). In the Bff-GermVet program, a total of 1,626 bacterial strains, obtained during a 27-month period (01/2004-03/2006) from 31 indications, was screened for susceptibility against 22 antimicrobial agents and two combinations of antimicrobial agents. Selected bacteria were additionally tested for their susceptibility against additional three combinations of antimicrobial agents and the corresponding single substances.This paper describes the overall aims and the structure of the program with particular reference to the sampling strategy, the methodology for susceptibility testing and the interpretive criteria used for evaluation of the results.  相似文献   

13.
采集山东不同地区鸡源沙门菌,根据Kauffmann-White方法测定分离株血清型,采用肉汤微量稀释法测试分离株对16种抗菌药物的敏感性,PCR方法检测10种耐药基因,分析耐药表型和耐药基因之间的关系。结果显示：共鉴定出沙门菌80株,其中印第安纳沙门菌60株。药敏试验证实：60株印第安纳沙门菌对阿莫西林-克拉维酸、头孢唑啉、多黏菌素、氨苄西林、多西环素和甲氧苄啶等16种抗菌药物普遍耐药。88.33%菌株多重耐药分布在12~15耐,未发现3耐以下的菌株。PCR扩增出int1,blaTEM,aac（6’）-Ib-cr,floR,catA1,tetA,strA,cmlA 8种耐药基因。超过90%的菌株携带int1,blaTEM,floR和aac（6’）-Ib-cr耐药基因。上述结果表明,耐药表型及耐药基因的符合呈现相关性。  相似文献   

14.
为调查山东省禽源致病性大肠杆菌流行的血清型及耐药性,从山东部分地区的45家养禽场分离到致病性大肠杆菌96株,应用微量平板凝集试验进行了血清型鉴定,共鉴定出18种血清型,其中优势血清型6种,分别为O78、O2、O15、O18、O143、O88,占定型致病性菌株的64％。抗菌药物敏感性试验发现,96株大肠杆菌对20种药物有不同程度的耐药性。75％以上的菌株对氨苄青霉素、阿莫西林、土霉素等5种抗菌药耐药,50％以上的菌株对卡那霉素、多西环素、环丙沙星等7种抗菌药表现为耐药;所有分离株存在多重耐药现象,75％的受检菌对9种或9种以上的被测药物耐药。结果表明,O78、O2、O15、O18、O143、O886种血清型是山东省部分地区近年来禽源致病性大肠杆菌的优势血清型,且禽源致病性大肠杆菌的耐药现象严重,有必要加强耐药性检测,以指导兽医临床合理使用抗菌药物。  相似文献   

15.
One hundred and fifty-two predominantly feline isolates of Bordetella bronchiseptica were tested for their susceptibility to seven antimicrobial agents using an agar dilution method. The majority of isolates tested by the agar dilution method were resistant to trimethoprim (MIC90 500 μg/ml) and ampicillin (MIC90 > 32 μg/ml) but sensitive to tetracycline, doxycycline and enrofloxacin (MIC90 2 μg/ml for all three agents). The isolates showed a spectrum of susceptibility to sulphadiazine and clavulanate potentiated amoxycillin. The MIC's of twenty-nine of the 152 isolates were then compared for five of the antimicrobial agents using the E-test (AB Biodisk, Sweden), a recently introduced method for measuring the MIC's of antimicrobial agents based on the diffusion of a pre-defined antibiotic gradient from a plastic strip. Comparisons with the E-test demonstrated an overall agreement (±1 log2 dilution) with the agar dilution method of 79.4% and an agreement within ±2 log2 dilutions of 96.2%.  相似文献   

16.
During the BfT-GermVet monitoring program, Pseudomonas (P) aeruginosa from dogs and cats (n = 99) as well as Arcanobacterium (A.) pyogenes from cattle and swine (n = 90) were examined for their antimicrobial susceptibility. In general, P. aeruginosa is known to be resistant against many antimicrobial agents whereas A. pyogenes is thought to be susceptible to most agents in-vitro. However, representative and actual minimum inhibitory concentration (MIC) values are missing for both veterinary pathogens. In the present study, MIC values were determined and categorized according to the recommendations given in the Clinical and Laboratory Standards Institute (CLSI) documents M31-A2 and M31-S1. For susceptibility testing of A. pyogenes, the CLSI methodology was slightly modified. Specific breakpoints were not available for most of the antimicrobial agents tested. P. aeruginosa isolates from infections of the skin, ear and mouth as well as the urinary and genital tract of dogs and cats were either resistant or exhibited high MIC values to most antimicrobial agents tested. However, gentamicin resistant isolates were observed in only 27% and 11% (intermediate isolates 29% and 39%), respectively. For the same bacterium/host animal/organ system combinations, enrofloxacin resistance was detected in only 24% and 11% of the isolates (intermediate isolates 49% and 61%). For A. pyogenes, resistance was most prevalent against tetracycline (33%-56%, bovine and porcine isolates) and sulfonamides (26%-40%, bovine isolates).  相似文献   

17.
为了解不同抗菌药物对大肠杆菌体外耐药诱导株的MIC变化特点,以盐酸四环素、盐酸环丙沙星、水杨酸钠、氯霉素作为诱导剂,采用1／2×MIC诱导法,对大肠杆菌质控菌株ATCC25922进行体外诱导试验。于诱导前对试验菌株进行形态学观察和生化鉴定,并于诱导过程中对试验菌株进行形态学观察。于诱导前测定16种抗菌药物对质控菌株的MIC,并于诱导剂浓度达到128×MIC时,测定16种抗菌药物对4株诱导菌株的MIC。结果表明,试验菌株的形态特征和生化反应特性与大肠杆菌一致。诱导前,16种抗菌药物对质控菌株的MIC为0．25-64．00μg／mL;头孢噻肟、盐酸四环素、土霉素、甲砜霉素、诺氟沙星、头孢西丁等抗菌药物对盐酸四环素诱导株的MIC与质控菌株相比．提高幅度均达到或超过4倍,均具有显著性意义;头孢噻肟对盐酸环丙沙星诱导株和氯霉素诱导株的MIC与质控菌株相比．提高倍数都超过了4倍,而其余抗菌药物的MIC变化均无显著性意义。水杨酸钠诱导剂浓度大于16×MIC时,菌株不能生长。结果提示。抗菌药物对盐酸四环素诱导株的MIC变化最明显,表明大肠杆菌在四环素的选择性压力下较易产生耐药性。  相似文献   

18.
The aim of this retrospective study was to evaluate the antimicrobial resistance rates and the trend in resistance of Actinobacillus pleuropneumoniae isolated from pigs in Italy from 1994 to 2009. A total of 992 A. pleuropneumoniae isolates were tested for their susceptibility to a panel of antimicrobial agents in a disk diffusion method. Resistance to 7 drugs (amoxicillin, amoxicillin/clavulanic acid, ampicillin, cefquinome, cotrimoxazole, penicillin G and tilmicosin) showed a significant increasing trend over the time, while for 2 drugs (gentamycin and marbofloxacin) a significant decrease was observed. Resistance to the remaining 14 antimicrobial agents tested did not change significantly over the study period. Most of the isolates retained high susceptibility to antimicrobials usually effective against A. pleuropneumoniae such as amphenicols, fluoroquinolones and ceftiofur. However, high rates of resistance were observed for potentiated sulfa drugs, tetracyclines and penicillins which are currently recommended antimicrobials for pig pleuropneumonia therapy. Our results suggest the importance of continued monitoring of A. pleuropneumoniae clinical isolates in order to choose the most appropriate treatment of infections and to control the increase of resistance to currently used antimicrobials.  相似文献   

19.
The determination of minimum inhibitory concentrations by broth microdilution is recommended as method of choice for susceptibility testing of veterinary bacterial pathogens. Accordingly, broth microdilution is used in veterinary routine diagnostic laboratories at a progressive rate. To reduce the costs of susceptibility testing, it is reasonable to develop widely accepted uniform microtitre plate layouts that are produced in large quantities. Such microtitre plate layouts have already been developed and published for the susceptibility testing of pathogens from food-producing animals. However, a microtitre plate layout, especially designed for the testing of bacteria from dogs and cats, should be available, too. The choice of the antimicrobial agents or combinations of antimicrobial agents to be included in a suitable layout should be based on the following criteria: (1) the approval and availability of an antimicrobial agent or combination of agents, (2) known cross-resistances, and (3) availability of approved clinical breakpoints. The latter point is of particular importance for the choice of the numbers of concentrations per antimicrobial agent tested and the range of test concentrations. Taking into account these aspects, a science-based layout proposal for microtitre plates, which are suitable for routine testing of bacteria from dogs and cats, is presented and discussed.  相似文献   

20.
Isolates of Staphylococcus aureus (106) from bovine mastitis were tested for susceptibility to antimicrobial agents. beta-lactamase was produced by 69.8 per cent of isolates and 7.5 per cent were resistant to streptomycin (minimum inhibitory concentration more than 32 micrograms/ml). Resistance to other agents was rare. Intrinsic resistance or tolerance to beta-lactam antibiotics was not found.  相似文献   

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