家兔呼吸道疾病病原分离鉴定与药敏试验

随着家兔养殖的集约化和规模化,兔场呼吸道疾病呈增加趋势.笔者于2009～2010年走访了成都周边地区规模化兔场,发现该病具有普遍性,患病成年兔表现为流黏液性或脓性鼻涕,打喷嚏,剖检主要见肺实变、出血性肺炎、化脓性肺炎或纤维素性胸膜肺炎,成年兔耐受力强,一般不死亡,种兔不发情;患病幼兔表现为流黏液性鼻涕和打喷嚏,急性病例常突然死亡,剖检多见出血性肺炎.     

Antimicrobial susceptibility patterns and sensitivity to tulathromycin in goat respiratory bacterial isolates

Bacterial pneumonia is a common and often life-threatening respiratory problem in both meat and dairy goats. Options for approved antibiotic therapy in goats to combat these bacterial infections are severely limited and frequently drugs must be used in an extra-label manner. Tulathromycin, a triamilide macrolide antimicrobial drug shown to be effective against swine and cattle respiratory bacterial agents, has been identified as a potentially useful drug in caprines. The present study was conducted to determine the susceptibility of recognized bacterial respiratory pathogens to commonly prescribed antimicrobials, with a particular emphasis on the efficacy of tulathromycin against these agents. Minimum inhibitory concentration (MIC) testing using microbroth dilution was performed on a collection of 45 Mannheimia haemolytica, 11 Pasteurella multocida, and 11 Bibersteinia trehalosi isolates from the lungs of goats with clinical pneumonia. To further characterize efficacy of tulathromycin against these pathogens, minimum bactericidal concentration (MBC) testing and kinetic killing assays were conducted. Most isolates were susceptible to the antimicrobials tested; however, increased resistance as demonstrated by higher MIC values was seen in all species to penicillin, in P. multocida to sulfadimethoxine, and in B. trehalosi to the tetracyclines. All isolates were susceptible to tulathromycin, which demonstrated a high killing efficiency in both bactericidal assays. Results of this study indicate that most goat pneumonic bacterial pathogens remain susceptible to commonly prescribed antibiotics, although some evidence of resistance was seen to certain drugs; and that tulathromycin is highly effective against goat respiratory pathogens which could make it a valuable medication in this species.     

Antimicrobial susceptibility of mastitis pathogens from first lactation and older cows

Increasing antimicrobial resistance has become a serious concern worldwide and antimicrobial use in animal agriculture is currently under scrutiny. Mastitis is the most common reason for antibiotic use in dairy herds and thus, antimicrobial resistance of mastitis pathogens has received recent attention. The purpose of this study was to describe and compare antimicrobial susceptibility of mastitis pathogens isolated at calving from first lactation and older cows. A total of 202 bacteria were isolated from intramammary infections (IMIs) within 3 days after calving over a 16-month study period in the Krauss Dairy Research Herd at the Ohio Agricultural Research and Development Center (OARDC) in Wooster, OH. Of these IMIs, 78% were caused by coagulase-negative staphylococci (CNS). Forty-four percent of them were resistant to at least one antibiotic. Most resistance was observed against penicillin, 39% of the isolates from older cows and 26% from first lactation cows being resistant to penicillin (P > 0.05). Also MIC90 for penicillin was higher among isolates from older cows. On the other hand, resistance to tetracycline was more common and MIC90 higher among isolates from first lactation cows than from older cows. Differences in the proportions of resistant isolates between first lactation and older cows were not statistically significant, though. The resistance patterns of the CNS isolated during the study are concordant with antimicrobial usage in the study herd. This is in agreement with the generally accepted notion that selection pressure from the use of antibiotics is a main factor in development of antibiotic resistance.     

Antimicrobial susceptibility of bifidobacteria isolated from gastrointestinal tract of calves

Fifty bifidobacterial strains isolated from different parts of gastrointestinal tract of calves during the milk-feeding period were tested for susceptibility to 28 antibiotics using disc diffusion method on TPY agar. Spectrum of antibiotics included commonly used medicaments in veterinary medicine. Seven strains from culture collection DSMZ were taken as a control. Most of the strains tested were susceptible to penicillins, cephalosporins, macrolids, chloramphenicols, bacitracin, linkomycin and resistant to aminoglycosides and aminocyclitols, quinolones, sulphonamides and colistin sulphate. All tetracyclines and enrofloxacin showed a variable effect against bifidobacterial strains. Our results suggest that strains resistant to antibiotics tested seem to be suitable for administration to young ruminants during antibiotic treatment.     

Mycoplasmas isolated from the respiratory tract of cattle and goats in Tanzania

A microbiological study of the mycoplasma flora in the respiratory tracts of cattle and goats in selected regions of Tanzania is described. In the examination of cattle, mycoplasmas were isolated from 60 (17.8%) of the 338 examined lung samples, 8 (47.1%) of the 17 lymph nodes, 4 (13.3%) of the 30 pleural fluid samples and 4 (3.9%) of the 103 nasal swabs examined. All the isolates were identified as Mycoplasma mycoides subsp. mycoides, Small Colony type except for one isolate from pleural fluid which was identified as Mycoplasma arginini. M. mycoides subsp. mycoides, Small Colony type was isolated from samples originating from Dodoma, Iringa, Mbeya, Morogoro and Shinyanga regions where outbreaks of contagious bovine pleuropneumonia had been reported. In the examination of goats, mycoplasmas were isolated from 54 (34.0%) of the 159 examined lung samples, 41 (18.1%) of the 226 nasal swabs and 4 (40.0%) of the 10 pleural fluid samples. The species demonstrated were Mycoplasma capricolum subsp. capripneumoniae, M. mycoides subsp. mycoides, Small Colony type Mycoplasma ovipneumoniae and M. Capricolum subsp. arginini. The isolation of M. capripneumoniae in the Coast and Morogoro regions confirmed the presence of contagious caprine pleuropneumonia in the regions.     

Antimicrobial susceptibility patterns of Salmonella isolates from cattle in feedlots

OBJECTIVE: To evaluate the antimicrobial susceptibility patterns of Salmonella isolates from feedlot cattle. DESIGN: Cross-sectional study. SAMPLE POPULATION: 263 Salmonella isolates. PROCEDURES: Fecal samples were collected from the floor of 2 pens in each of 100 feedlots. Two hundred eighty Salmonella isolates were recovered after bacteriologic culture from 38 pens. Of these, 263 isolates were available for antimicrobial susceptibility testing to 16 antimicrobials, using microbroth dilution breakpoint plates. RESULTS: Less than 5% of isolates were resistant to any of the antimicrobials tested, with the exception of sulfamethoxazole (15; 5.7%) and tetracycline (61; 23.2%). Most isolates (197; 74.9%) were susceptible to all antimicrobials tested, whereas 18 (6.8%) were resistant to 2 or more antimicrobials. The percentage of isolates with resistance to any antimicrobial varied by serotype. The percentage of isolates resistant to various antimicrobials was not related to concurrent use of antimicrobials in the feed. CONCLUSIONS AND CLINICAL RELEVANCE: With the exception of tetracycline and sulfamethoxazole, resistance of Salmonella isolates to any of the antimicrobials was uncommon. Most isolates were susceptible to all antimicrobials tested. Antimicrobial resistance was not related to the presence of antimicrobials in the ration being fed at the time of sample collection.     

羊副结核性腹泻病病原体分离及药敏试验

为了诊断与治疗阿拉善盟阿左旗发生的羊腹泻病,试验对从阿拉善盟阿左旗采集的病料进行病原体分离培养、抗酸染色、革兰染色、ELISA检测,并对分离到的菌株进行药敏试验。结果表明:从肠系膜淋巴结分离到抗酸染色阳性、革兰染色阳性的短粗杆状副结核杆菌,2份血清中均有与副结核杆菌抗原结合的相应抗体的存在;分离菌对环丙沙星和卡那霉素敏感,对头孢呋肟和阿奇霉素中度敏感,对其他药物均产生不同程度的耐药性。     

Antimicrobial resistance of Staphylococcus aureus and coagulase negative staphylococci isolated from mastitis milk samples from sheep and goats

Staphylococcus aureus and coagulase negative staphylococci (CNS) were isolated from ovine and caprine mastitis milk samples originating from more than 40 Swiss farms. CNS dominated as causal microorganisms of mastitis in small ruminants. By restriction fragment length polymorphism (RFLP) analysis of the groEL gene and sequencing of 16S rDNA, various CNS species were identified, albeit certain of them predominated. For susceptibility testing of mastitis pathogens to selected antibiotics, minimal inhibitory concentrations were determined. Of the 67 S. aureus and 208 CNS strains, 31.3 % and 8.2 % were resistant to penicillin, 29.9 % and 1.0 % to ampicillin, 1.5 % and 10.6 % to erythromycin, and 3.0 % and 7.7 % to tetracycline, respectively. Moreover, 10 CNS strains (4.8 %) were resistant to oxacillin and one CNS strain to sulfamethoxazole/trimethoprim. The results obtained describe for the first time the resistance situation of mastitis pathogens from sheep and goats in Switzerland. However, accompanying and preventing measures are also of importance in mastitis control of small ruminants.     

Antimicrobial susceptibility patterns of canine Staphylococcus intermedius isolates from veterinary clinical specimens

Sixty-six Staphylococcus intermedius isolates from canine clinical specimens were tested for susceptibility to various antimicrobial agents by the Bauer-Kirby disk diffusion method and a commercial microdilution system. All isolates were susceptible to cephalothin, cloxacillin, gentamicin, methicillin, and vancomycin. Resistance to ampicillin, penicillin G, and tetracycline was frequent. There was an overall 87% agreement of results from the disk diffusion and microdilution methods for 10 antimicrobial agents. There was greater than or equal to 94% agreement between the 2 methods for 7 antimicrobics; discrepancies were minor.     

Quantifying differences in total tract nutrient digestibilities between goats and sheep

Conclusions from narrative qualitative reviews on differences in total tract digestibilities between goats and sheep did not account for variability among studies. Therefore meta‐analytic techniques were used to describe the magnitude of these differences with numerical values. A unitless effect size (Hedges’ g) was applied within studies to measure differences in digestibilities of dry matter (DM; 104 comparisons), organic matter (OM; 93 comparisons), crude protein (CP; 85 comparisons), neutral detergent fibre (NDF; 74 comparisons), acid detergent fibre (ADF; 59 comparisons), cellulose (24 comparisons), hemicellulose (18 comparisons) and gross energy (GE; 29 comparisons). The absence and inability to describe independent factors which contributed to variation among studies necessitated the use of frequentist random effects and hierarchical Bayesian models in the calculation of summary statistics across studies. Digestibilities of DM, OM, CP, NDF, ADF and hemicellulose were higher (p < 0.05) in goats than sheep when all‐forage diets were fed. When concentrates were included in the diets, there were no such differences. Differences between goats and sheep in DM intake were found to be non‐significant. Differences in nutrient digestibilities of forages as sole feed implies that species‐specific values have to be used in feed formulation and feeding strategies. However, caution is needed when extrapolating results from stall‐feeding, which is how digestibility data are usually measured, to grazing conditions.     

Antimicrobial susceptibility of Actinobacillus pleuropneumoniae isolates from clinical outbreaks of porcine respiratory diseases

Limited data regarding the susceptibility of Actinobacillus pleuropneumoniae to antimicrobials has been published during recent years. Accordingly, the aim of the present study was to investigate the distribution of MICs for the isolates of A. pleuropneumoniae from diseased pigs in the Czech Republic between 2007 and 2009. A total of 242 isolates were tested for susceptibility to 16 antimicrobial agents by a broth microdilution method. A low degree of resistance was observed for florfenicol (0.8%), amoxicillin and clavulanic acid (0.8%), tilmicosin (1.2%), tiamulin (1.7%) and ampicillin (3.3%), whereas resistance to tetracycline was detected more frequently, 23.9% of isolates. Interestingly, resistance to florfenicol has not yet been reported in any study investigating antimicrobial resistance of A. pleuropneumoniae. By PCR the presence of the floR gene was confirmed in all florfenicol resistant isolates.     

Antimicrobial susceptibility patterns of Haemophilus parasuis from pigs in the United Kingdom and Spain

A total of 30 British and 30 Spanish Haemophilus parasuis isolates were tested for their susceptibility to 19 of the antimicrobials currently used in swine practice with a broth microdilution method in order to know the emergence of resistance against these compounds in this porcine pathogen. All the British isolates were susceptible to penicillin, ceftiofur, erythromycin, tilmicosin, enrofloxacin, and florfenicol, and most of them were susceptible to the remaining antimicrobials (the highest resistance rate found was of 20% to neomycin). In contrast, all the Spanish isolates were susceptible exclusively to florfenicol, and high proportions of resistance were encountered for penicillin, ampicillin, oxytetracycline, erythromycin, tilmicosin, tiamulin and trimethoprim+sulphamethoxazole; in addition, a bimodal or multimodal distribution, or tailing of Spanish isolates over the MIC range was observed for clindamycin, sulphonamides and tylosine tartrate, suggesting the development of acquired resistance. In addition, several multiresistance patterns were found among the Spanish isolates, 23.3% of them being resistant to at least eight antimicrobials, the same rate as that encountered for those being susceptible to all antimicrobials tested. This study showed that in general British H. parasuis isolates are susceptible to antimicrobial agents routinely used for treatment of porcine respiratory diseases; however, the Spanish isolates need a more continuous surveillance of their susceptibility patterns.     

Antimicrobial susceptibility patterns of thermotolerant Campylobacter strains isolated from food animals in Ethiopia

Thermotolerant Campylobacter spp. are frequent causes of diarrhoea in humans worldwide mostly originating from poultry. It has been suggested that extensive veterinary use of antibiotics is largely responsible for resistance in human isolates. During a 4-month period from January to April 2004, 192 Campylobacter spp. were isolated from fecal samples of 485 healthy food animals. The in vitro susceptibility to 12 antibiotics was determined by the agar disk diffusion method. Among the 192 Campylobacter spp. isolated, 135 (70.3%) were identified to be C. jejuni, 51 (26.6%) were C. coli and 6 (3.1%) were C. lari. C. jejuni was the most prevalent species in chickens (80.8%) versus 16.2% C. coli and 3.0% C. lari. All isolates found in pigs were C. coli. All strains were sensitive to chloramphenicol and ciprofloxacin and all were resistant to cephalothin. More than 90% of the strains were sensitive to clindamycin, erythromycin, gentamicin, nalidixic acid, norfloxacin, streptomycin and tetracycline. Resistance was found against ampicillin in 20% and trimethoprim-sulphamethoxazole in 37.5%. Resistance was not statistically different among C. jejuni, C. coli and C. lari (p>0.05). Multidrug resistance to two or more drugs was detected in 14.5% of strains. In conclusion, the study showed that antimicrobial resistance is found only at relatively low frequencies for most antimicrobial agents tested except for ampicillin and trimethoprim-sulphamethoxazole. The low percentages of resistance to most antimicrobial agents tested in this study may be the result of low/no usage of these agents as a growth promoters or treatment in the Ethiopian animal farm setting. The detection of multidrug resistant isolates may pose a threat to humans and further limits therapeutic options.     

Antibody prevalence against respiratory viruses in sheep and goats in North-Western Turkey

Respiratory viruses may infect both small and large ruminant species, and can be transmitted among those of species. Present study reports presence and serological distribution of bovine respiratory viral infections in sheep and goats in Marmara region of Turkey. Total of 388 sera, 228 from sheep and 160 from goats collected from 4 provinces were analysed. Neutralising antibodies specific to BVDV, BHV-1, BRSV, PI-3, BAV-1 and BAV-3 were investigated. Among 388 serum samples 32.1% were positive for BVDV, 23.0% for BHV-1, 72.9% for BRSV, 13.2% for PI-3, 86.0% for BAV-1 and 93.0% for BAV-3. There were significant differences observed between seroprevalence rates detected in neighbouring provinces. Prevalence of BVDV specific antibodies was extremely higher (p = 0.0009) in sheep, however, BHV-1 (p = 0.0001) and PI-3 (p = 0.0038) were more prevalent in goats. BRSV antibody prevalence was closely related to data obtained from cattle. This study demonstrates that, like in cattle herds, BRSV and adenoviruses are the possible common reason of respiratory diseases in small ruminants in the region.     

Antimicrobial susceptibility testing for bovine respiratory disease: Getting more from diagnostic results

Bovine respiratory disease (BRD) is one of the most common diseases of cattle worldwide. Given the significant bacterial component of this disease, antimicrobial agents remain one of the mainstays of therapy. However, the potential welfare and economic impact resulting from the selection of inappropriate antimicrobial therapy for BRD poses significant risks to both animal and animal owner. To determine the ‘best’ antimicrobial agent for a specific case, the decision-making process needs to incorporate all available evidence, often including the results of bacterial culture and antimicrobial susceptibility testing. While antimicrobial susceptibility testing can be a valuable diagnostic tool, integrating the test results into the clinical decision making process can be a challenging experience. This review details the process by which interpretive criteria for susceptibility tests are developed. Principles for how to best integrate antimicrobial susceptibility testing, both at the individual animal test and aggregate test levels, into the clinical decision making process are discussed. Non-traditional testing methodologies and how they may improve susceptibility testing in the future are also reviewed.     

In vitro susceptibility of porcine respiratory pathogens to tilmicosin.

Bacterial isolates obtained from swine with various clinical diseases were tested for susceptibility to tilmicosin by minimum inhibitory concentration (MIC) and Kirby-Bauer disk diffusion tests using National Committee on Clinical Laboratory Standards methodology. The tilmicosin MIC90 was < or =0.125 microg/ml for Erysiopelothrix rhusiopathiae, < or = 1 microg/ml for Haemophilus parasuis isolates, 8 microg/ml for Actinobacillus suis and Pasteurella multocida type A, 16 microg/ml for toxigenic and nontoxigenic P. multocida type D, 64 microg/ml for Bordetella bronchiseptica, and >128 microg/ml for Staphylococcus hyicus and Streptococcus suis. The results of disk diffusion testing matched well with the MIC results for each pathogen. This in vitro survey of tilmicosin activity against various swine isolates suggests that further clinical evaluation of tilmicosin in swine may be warranted for disease associated with E. rhusiopathiae, H. parasuis, and A. suis but not B. bronchiseptica, S. suis, or S. hyicus.