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1.
Riemerella anatipestifer, a gram-negative bacillus, is the causative agent of duck septicemia, a disease which could incur much economic loss in the duck industry. An indirect enzyme-linked immunosorbent assay (ELISA) has been developed to facilitate early detection of R. anatipestifer infection in ducks. The antigen used was a recombinant 41 kDa N-terminal fragment (rP45N') of a newly characterized R. anatipestifer potential surface protein, P45, which was expressed in Escherichia coli as an N-terminal GST fusion protein. The rP45N'-based ELISA successfully detected P45 antibodies in the sera of 20 ducks immunized with bacterin preparations of R. anatipestifer serotypes 1, 10 15, 19 and the ATCC11845 strain. Antibodies to P45 were also detected in the sera of 25% (75/296) of White Pekin ducks which were imported into Singapore from three different farms. Successful discrimination was obtained between sera from infected ducks and that of specific-pathogen free ducks (p<0.01). The rP45N'-GST antigen did not cross-react with antibodies in sera from guinea pigs which were infected with other gram-negative and gram-positive bacterial pathogens, including Aeromonas hydrophila, Citrobacter freundii, E. coli, Klebsiella pneumoniae, Pastuerella multocida, Proteus mirabilis, Salmonella spp., Serratia maccescens, Shigella sonnei and Yersinia enterocolitica. In addition, the DNA sequence encoding P45 was detected in R. anatipestifer serotypes 1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 14, 15, 16, 17, 18, 19 and the ATCC11845 strain, suggesting that P45 is probably also universally expressed in these R. anatipestifer serotypes. Thus, the ELISA described is applicable to the detection of R. anatipestifer infection in ducks.  相似文献   

2.
Riemerella anatipestifer is a gram-negative bacteria that can cause disease in a wide variety of wild and domesticated birds, especially waterfowl. The infection can be peracute, acute, or chronic. Although various routes of transmission have been proposed, to date, there is little information on the effects of route of transmission and challenge dosage on R. anatipestifer infection. Hence, the objective of this study was to determine the effect of route of inoculation and challenge dosage on R. anatipestifer infection and pathology. To achieve this objective, one hundred forty-seven 14-day-old white Pekin ducks (Anas platyrhynchos) were equally divided into 13 experimental groups (12 challenge and 1 control group). Each challenge group had 11 ducks. The control group had 15 ducks. Four routes of inoculation were evaluated (intranasal, oral, subcutaneous, and intravenous). Three dosage levels were evaluated for each inoculation route (10(2), 10(4), and 106 colony forming units [CFU]/ml). At the 106 CFU/ml dosage level, mortality was most associated with the subcutaneous (91%) and intravenous (82%) routes, followed by the nasal (18%) and oral (9%) routes. A unique pathologic lesion was found in the bursa of Fabricius and spleen of affected birds. Within the spleen and bursa of Fabricius, there were varying degrees of lymphoid depletion and necrosis within the cortical and medullary regions. These pathologic lesions have not been previously reported in ducks with R. anatipestifer infection.  相似文献   

3.
The objective of this study was to determine the pharmacokinetics of a long-acting formulation of ceftiofur crystalline-free acid (CCFA) following intramuscular injection in ball pythons (Python regius). Six adult ball pythons received an injection of CCFA (15 mg/kg) in the epaxial muscles. Blood samples were collected by cardiocentesis immediately prior to and at 0.5, 1, 2, 4, 8, 12, 18, 24, 48, 72, 96, 144, 192, 240, 288, 384, 480, 576, 720, and 864 hr after CCFA administration. Plasma ceftiofur concentrations were determined by high-performance liquid chromatography. A noncompartmental pharmacokinetic analysis was applied to the data. Maximum plasma concentration (Cmax) was 7.096 +/- 1.95 microg/ml and occurred at (Tmax) 2.17 +/- 0.98 hr. The area under the curve (0 to infinity) for ceftiofur was 74.59 +/- 13.05 microg x h/ml and the elimination half-life associated with the terminal slope of the concentration-time curve was 64.31 +/- 14.2 hr. Mean residence time (0 to infinity) was 46.85 +/- 13.53 hr. CCFA at 15 mg/kg was well tolerated in all the pythons. Minimum inhibitory concentration (MIC) data for bacterial isolates from snakes are not well established. For MIC values of < or =0.1 microg/ml, a single dose of CCFA (15 mg/kg) provides adequate plasma concentrations for at least 5 days in the ball python. For MICs > or =0.5 microg/ml, more frequent dosing or a higher dosage may be required.  相似文献   

4.
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   

5.
A study was performed to determine the residues in blood and edible tissues of healthy ducks (25 days old, mean body weight 1.0+/-0.13 kg) after subcutaneous administration of ceftiofur sodium at a dose rate of 2 mg/kg body weight (Group I) and 4 mg/kg body weight (Group II). Blood, muscle, liver, kidney, and fat samples were collected from all of ducks on the 1st, 2nd, 3rd, 4th, and 5th day after treatment of drug, and ceftiofur was analyzed with a high-performance liquid chromatography (HPLC) assay with results reported as ceftiofur-free acid equivalent (CFAE). To study the spiked recovery, blank plasma and tissues were spiked with two different concentrations of ceftiofur sodium (0.1, 0.5 microg/g). Average recovery values for all samples ranged from 70.3 to 87.3%. In the group I, desfuroylceftiofur acetamide (DCA) was not detected in all of plasma, muscle, liver, and fat tissues on the 1st day after treatment. But, kidney samples on the 1st day were detected DCA (0.059+/-0.01 microg CFAE/g tissue). On the 2nd day of post-treatment, the concentrations of DCA in all tissues were lower than the detection limit, 0.05 microg CFAE /g tissue. In the group II on the 1st day after treatment, the concentration of DCA was 0.124+/-0.06 microg CFAE/g tissue, 0.103+/-0.03 microg CFAE/g tissue, and 0.071+/-0.010 microg CFAE/g tissue in plasma, kidney, and muscle samples, respectively. On the 2nd day after treatment of ceftiofur, the concentrations of DCA in all tissues were lower than 0.05 microg CFAE/g tissue. According to our results, the concentrations of DCA on the 1st day after treatment with 2 mg/kg body weight were below 0.05 microg CFAE/g tissue equivalent in all tissues except for kidney. On the 2nd day after administration at the dose of 4 mg/kg body weight, no DCA was also detected in all of the tissues although DCA was detected in all samples on the 1st day.  相似文献   

6.
Ceftiofur concentrations in an infected and uninfected environment were compared and the efficacy of locally administered ceftiofur was evaluated in an experimental infection with Staphylococcus aureus in tissue cages. Eight ponies had tissue cages (TCs) implanted s.c. on each side of the neck. Into one of the cages 150 mg of ceftiofur was administered and fluid samples were taken to determine ceftiofur concentrations. After 1 week the other TC was infected with S. aureus and subsequently treated with 150 mg ceftiofur administered locally into the TC once daily for 21 days. Samples of fluid were taken to determine ceftiofur concentrations and for bacterial counts. Ceftiofur concentrations did not differ significantly in the infected and uninfected environments after single dose of 150 mg of ceftiofur. Concentrations were considerably in excess of the minimum inhibitory concentration (MIC) of the S. aureus strain used. A marked decrease of viable bacteria in tissue cage fluid (TCF) occurred. In five of seven ponies; however, the infection was not eliminated and abscess formation occurred. Therefore, local application of ceftiofur alone is not advisable for infections with S. aureus in secluded sites in horses, but should be used only with adjunctive therapy.  相似文献   

7.
The minimum inhibitory concentrations (MICs) of oxytetracycline, cephapirin, cephapirin/mecillinam, cefquinome, ceftiofur and enrofloxacin, candidate antibiotics for the principal bacteria associated with uterine infections: Escherichia coli, Arcanobacterium pyogenes and the anaerobic bacteria Fusobacterium necrophorum and Prevotella melaninogenicus, were determined by the agar dilution method. The bacteria were isolated from animals with clinical metritis and/or endometritis. For E coli, cefquinome and enrofloxacin had the lowest MIC90 and MIC50 values (< 0.06 microg/ml), and oxytetracycline and cephapirin had the highest values. For A pyogenes, oxytetracycline had the highest MIC50 value (16 microg/ml), but all the cephalosporins had values below 0.06 microg/ml. For the anaerobic bacteria, enrofloxacin and oxytetracycline had the highest MIC50 values but all the cephalosporins had values of 0.06 microg/ml or below.  相似文献   

8.
The generation of protective immunity against Riemerella anatipestifer infection in ducks were investigated by immunizations with recombinant glutathione sulfatransferase (GST) fusion's proteins of OmpA, a 42kDa major outer membrane protein, and P45N', a 41kDa N-terminal fragment of a newly identified 45kDa potential surface protein from R. anatipestifer. The DNA encoding OmpA and P45N' were isolated from R. anatipestifer serotype 15 (field strain 110/89) and serotype 19 (reference strain 30/90), respectively. Immunoblotting and ELISA results showed that the purified recombinant proteins induced the production of antibodies in immunized ducks. However, neither was protective against subsequent challenge with the virulent serotype 15 strain, 34/90. All the five ducks immunized with formalinized R. anatipestifer strain 34/90 survived the challenge with the homologous strain whereas six out of seven ducks in the non-immunized control group died within a week following the challenge.  相似文献   

9.
A broth microdilution technique was used to determine the antimicrobial susceptibility of 15 field isolates of Mycoplasma hyorhinis to 10 antimicrobial agents, representative of different classes, and contrasting newer agents to existing ones. For the macrolides, the MIC(90) for tylosin and tilmicosin was 1 and 4 microg/ml, respectively, but was > or = 16 microg/ml for erythromycin. Tetracycline, lincomycin and enrofloxacin each had an MIC(90) of 2 microg/ml. The mycoplasma had similar levels of susceptibility to the aminoglycoside and aminocyclictol classes exhibiting an MIC(90) of 4 microg/ml for gentamicin and 2 microg/ml for spectinomycin. The isolates exhibited high MICs to trimethoprim/sulfamethoxazole with an MIC(90) > or = 16/304 microg/ml. In summary, M. hyorhinis isolates from the US had low MICs against a variety of antimicrobials tested, with the exception of erythromycin and trimethoprim/sulfamethoxazole.  相似文献   

10.
北京地区鸭传染性浆膜炎的流行病学调查   总被引：35，自引：1，他引：34  
１９９７ 年１０ 月～１９９８ 年１２ 月, 从北京地区３０ 个商品鸭场随机收集自然死亡鸭５６１ 只, 经过病理剖检和细菌分离鉴定, 确定２９ 个鸭场存在鸭传染性浆膜炎, ６１ ％ 的病例患有本病, 其日龄范围为７ ～４２ 日。结果说明,一年四季中, 鸭传染性浆膜炎均是引起北京地区肉鸭死亡的主要疾病, 广泛分布于该地区各养鸭场; 肉鸭日龄越小, 对本病越易感, 随着肉鸭日龄的增加, 尤其在５ ～６ 周龄后, 肉鸭对本病的抵抗力增加。从死亡鸭的脑、心血、肝脏、脾脏和胆囊均易分离到鸭疫里氏杆菌, 但从脑组织最易分离到该菌; 共分离到鸭疫里氏杆菌４２１ 株, 分别属于１ 、２ 、６ 、１０ 、１３ 、１４ 型, 其中１ 、２ 、６ 、１０ 型占总分离株的９６ ％ , 是目前主要流行的血清型。给健康鸭注射各血清型分离株的液体培养物均可复制出鸭传染性浆膜炎的临床症状和病理变化, 并引起鸭死亡。１０９ 株受试菌对红霉素、青霉素 Ｇ、新生霉素、痢特灵、氯霉素高度敏感。  相似文献   

11.
以1型鸭疫里氏杆菌(RA)全基因组保守区域ompA基因的重组表达产物为包被抗原,建立了检测RA血清抗体的间接ELISA方法。原核表达的重组ompA蛋白经纯化后作为包被物,以方阵滴定法确定抗原最佳包被浓度为1.5μg/mL,待检血清最佳稀释度为1∶100。与普通的微量凝集试验相比较,该方法灵敏度高于凝集试验约16倍～128倍。与鸭源大肠埃希菌、鸭源多杀性巴氏杆菌、鸭链球菌、鸭源呼肠病毒、鸭肝炎病毒和鸭瘟病毒感染鸭血清均无交叉反应,表明该方法特异性好。利用该方法检测了雏鸭免疫RA灭活油乳剂疫苗之后血清抗体水平。  相似文献   

12.
In order to understand the prevalence of the duck infectious serositis in different regions,and further to determine the sensitivity of the commonly used drugs for the Riemerella anatipestifer in these area.Bacteria were isolated from suspected infected ducks in Yunfu, and Kaiping in Guangdong province and Changshan in Zhejiang province.The isolated bacteria were identified by differential culture, microscopic examination and biochemical test. Micro dilution method was carried out in drug sensitivity test, and the MIC values of the isolated strains to the commonly used drugs were determined.As a result, a total of 16 strains of Riemerella anatipestifer were isolated and identified from three areas. Data of the MIC showed that all isolates were highly sensitive to cephalosporins and florfenicol;Doxycycline andspectinomycin were sensitive too,but enrofloxacin, neomycin and other tested drugs showed different degrees of resistance.The present study provided a systematic method for the isolation and identification of the Riemerella anatipestifer and for the drug sensitivity test.At the same time, it also provided theoretical guidance for the rational drug control of the duck infectious serositis.  相似文献   

13.
Minimum inhibitory concentrations (MICs) were determined for 1570 bacteria from eight geographic locations (1204 Escherichia coli, 231 other enteric gram-negative bacilli [including Citrobacter spp., Enterobacter spp., Klebsiella spp., Proteus spp., and Salmonella spp.], 31 Pseudomonas spp., 18 coagulase-positive staphylococci, 26 coagulase-negative staphylococci, and 55 streptococci and enterococci) by the National Committee for Clinical Laboratory Standards broth microdilution procedure. Antimicrobial agents tested included ampicillin, ceftiofur, enrofloxacin, erythromycin, florfenicol, gentamicin, neomycin, spectinomycin, sulfamethazine, tetracycline, and trimethoprim/sulfadiazine. Against the E. coli strains tested, ceftiofur, enrofloxacin, gentamicin, and trimethoprim/sulfadiazine were the most active compounds with MIC at which 50% of the strains are at or below (MIC50) = 0.5, < or = 0.03, 0.5, and 0.13 microg/ml, respectively, and MIC at which 90% of the strains are at or below (MIC90) = 1.0, 0.13, 32.0, and 2.0 microg/ml, respectively. Ampicillin, florfenicol, neomycin, and spectinomycin were the next most active compounds against the E. coli strains, with MIC50 = 4.0, 4.0, 16.0, and 16.0 microg/ml, respectively. MIC90 values for these compounds against E. coli strains were > 32.0, 8.0, 512.0, and > 128.0 microg/ml, respectively. The remaining compounds exhibited limited, strain-dependent activity against the E. coli strains tested. As with the E. coli, enrofloxacin, ceftiofur, and trimethoprim/sulfadiazine were also the most active compounds against the 231 other enteric organisms tested, with MIC50 < or = 1.0 microg/ml for all of these genera. The remaining compounds exhibited limited activity against these genera. Against the gram-positive cocci tested, ampicillin, enrofloxacin, ceftiofur, and trimethoprim/sulfadiazine were most active, whereas the remaining compounds exhibited strain-dependent activity. When MIC data for E. coli were summarized separately, differences were observed between the geographic locations for the various antimicrobial agents. In conclusion, ceftiofur, enrofloxacin, and trimethoprim/sulfadiazine were the most active of the compounds tested against all of the bacterial strains.  相似文献   

14.
为了解不同地区鸭疫里氏杆菌病的流行情况,并进一步测定这些地区鸭疫里氏杆菌对常用抗菌药物的敏感性。本试验从广东云浮、广东开平、浙江常山3个地区疑似传染性浆膜炎病鸭中进行了细菌分离,通过鉴别培养、染色镜检、生化试验等对分离菌进行鉴定。采用微量稀释法测定了分离菌株对常用药物的最小抑菌浓度。结果从3个地区共分离鉴定出16株鸭疫里氏杆菌。药敏试验结果表明,3个地区鸭疫里氏杆菌均对头孢类和氟苯尼考高度敏感,对多西环素、大观霉素比较敏感;对恩诺沙星,新霉素等其他受试药物呈不同程度的耐药。本研究为鸭疫里氏杆菌的分离鉴定与药物敏感性测定提供了系统方法,为临床选择合理药物防制鸭传染性浆膜炎提供了理论指导。  相似文献   

15.
Ceftiofur sodium, a broad-spectrum cephalosporin, is active against gram-positive and gram-negative pathogens of veterinary importance. Two studies were designed to compare the intramuscular bioavailability of the current sodium salt and the new hydrochloride salt in pigs at doses of either 3 mg or 5 mg ceftiofur equivalents (CE)/kg body weight. Twenty-six healthy young pigs were selected for these two-period, two-treatment crossover studies, 12 for the 3 mg/kg study and 14 for the 5 mg/kg study. Each animal received one intramuscular (i.m.) injection of ceftiofur sodium and one i.m. injection of ceftiofur hydrochloride with a 14-day washout period between the two treatments. Blood samples were collected serially for up to 96 h postinjection. Plasma samples were then analysed using a validated assay that measures ceftiofur and all desfuroylceftiofur-related metabolites by high-performance liquid chromatography. In the 3 mg/kg dosage study, average maximum plasma concentration (C(max)) after administration of ceftiofur sodium was 15.8+/-3.40 microg/mL at 0.4-4 h after injection. After administration of ceftiofur hydrochloride, the C(max) was 11.8+/-1.67 microg/mL at 1-4 h after injection. Concentrations of ceftiofur and metabolites 72 h after the injection were 0.392+/-0.162 microg/mL for ceftiofur hydrochloride and 0.270+/-0.118 microg/mL for ceftiofur sodium. The mean area under the curve (AUC), from time 0 to the limit of quantitation (AUC(O-LOQ)) after ceftiofur hydrochloride administration, was 216+/-28.0 microg x h/mL, compared to 169+/-45.4 microg x h/mL after ceftiofur sodium administration. The calculated time during which plasma concentrations remained above 0.02 microg/mL (t(>0.2)) was 85.3+/-10.6 h for ceftiofur sodium and 77.2+/-10.7 h for ceftiofur hydrochloride. In the 5 mg/kg dosage study, C(max) after administration of ceftiofur sodium was 28.3+/-4.45 microg/mL at 0.33-2 h after injection. After administration of ceftiofur hydrochloride, the C(max) was 29.7+/-6.72 microg/mL at 0.66-2 h after injection. Concentrations of ceftiofur and metabolites 96 h after the injection were 0.274+/-0.0550 microg/mL for ceftiofur hydrochloride and 0.224+/-0.0350 microg/mL for ceftiofur sodium. The mean AUC(O-LOQ) after ceftiofur hydrochloride administration was 382+/-89.8 microg x h/mL compared to 302+/-54.4 microg x h/mL after ceftiofur sodium administration. The t(>0.2) was 78.9+/-9.65 h for ceftiofur sodium and 94.2+/-8.64 h for ceftiofur hydrochloride. Based on the similarity of the pharmacokinetic parameters of the sodium and hydrochloride formulations of ceftiofur, similar therapeutic efficacy can be inferred for the two products.  相似文献   

16.
OmpA is a virulence factor of Riemerella anatipestifer   总被引：1，自引：0，他引：1  
Hu Q  Han X  Zhou X  Ding C  Zhu Y  Yu S 《Veterinary microbiology》2011,150(3-4):278-283
Riemerella anatipestifer infection is probably the most economically important disease of farm ducks worldwide. The pathogen R. anatipestifer causes septicemia anserum exsudativa in ducks, but little is known about the molecular basis of its pathogenesis and the virulence factors involved. In this study, by deleting ompA gene from R. anatipestifer serotype 2 strain Th4, we constructed a mutant strain Th4ΔompA to investigate whether R. anatipestifer OmpA is an important virulence factor. Results showed that although the growth curve, bacterial and colony morphology of Th4ΔompA in tryptic soybean broth (TSB) or on TSB agar were similar to its parent strain Th4, the adhesion and invasion capacities of mutant strain to Vero cells were decreased significantly. Furthermore, the median lethal dose (LD(50)) of both strains was determined to measure the virulence with 10-day-old Cherry Valley ducklings. The results showed that LD(50) of Th4ΔompA mutant was >10(10) colony forming units (CFU), it was attenuated significantly in comparison with that of Th4 which LD(50) was 4.41 × 10(8) CFU. Additional analysis indicated that blood bacterial loading of ducklings infected with the Th4ΔompA mutant were much lower than those of Th4-infected ducklings. The results demonstrate that OmpA is a virulence factor of R. anatipestifer, and that it may act as an adhesin.  相似文献   

17.
Minimum inhibitory concentrations (MICs) of 10 antimicrobial agents were determined for Pasteurella multocida from cattle and pigs (72 and 68 isolates, respectively). Higher MICs were observed with oxytetracycline, doxycycline, tilmicosin and thiamphenicol for porcine isolates than for bovine isolates. Enrofloxacin was the most active, with an MIC for 90% of the isolates (MIC90) of 0.05 microg/ml for both bovine and porcine isolates. Aspoxicillin exhibited the same excellent activity against penicillin-susceptible isolates as ceftiofur, with MICs ranging from < or = 0.025 to 0.1 microg/ml. Aminoglycosides were less active, with an MIC90 of > 100 microg/ml for both bovine and porcine isolates.  相似文献   

18.
Staphylococcus aureus is an important opportunist that can cause superficial to life-threatening illnesses in a variety of animal species. In poultry, this organism has been implicated in osteomyelitis, synovitis, and cellulitis. Whereas most infections can be treated with antibiotics, because of the organism's propensity to acquire antimicrobial resistance, it is important to continually monitor antibiotic susceptibilities of clinical isolates. We surveyed 77 clinical poultry S. aureus isolates, collected from 1998 to 2000, for susceptibilities to a panel of 18 antimicrobial agents. Thirty-six percent of isolates were susceptible to all antibiotics. Forty-three and 16% of avian S. aureus were resistant to one and two antibiotics respectively. Staphylococcus aureus isolates were commonly resistant to tetracycline (40%; minimal inhibitory concentration [MIC]90 > 32 microg/ml), lincomycin (19%; MIC90 > 32 microg/ml), erythromycin (12%; MIC90 > 8 microg/ml), and kanamycin (8%; MIC90 < 128 microg/ml). All S. aureus isolates were susceptible to chloramphenicol, gentamicin, streptomycin, nitrofurantion, linezolid, quinupristin/dalfopristin, vancomycin, and the production antimicrobials virginiamycin, salinomycin, and flavomycin. A periodic assessment of antimicrobial susceptibilities of important avian pathogens like S. aureus will be important in helping the clinician's choice of antibiotic to control infection.  相似文献   

19.
OBJECTIVE: To determine the pharmacokinetics of ceftazidime following subcutaneous administration and continuous IV infusion to healthy dogs and to determine the minimum inhibitory concentration (MIC) of ceftazidime for clinical isolates of Pseudomonas aeruginosa. ANIMALS: 10 healthy adult dogs. PROCEDURE: MIC of ceftazidime for 101 clinical isolates of P aeruginosa was determined in vitro. Serum concentrations of ceftazidime were determined following subcutaneous administration of ceftazidime (30 mg/kg of body weight) to 5 dogs and continuous IV infusion of ceftazidime (loading dose, 4.4 mg/kg; infusion rate, 4.1 mg/kg/h) for 36 hours to 5 dogs. RESULTS: The MIC of ceftazidime for P aeruginosa was < or = 8 microg/ml; all isolates were considered susceptible. Following SC administration of ceftazidime, mean beta disappearance half-life was 0.8 hours, and mean serum ceftazidime concentration exceeded the MIC for P aeruginosa for only 4.3 hours. Two dogs had gastrointestinal tract effects. Mean serum ceftazidime concentration exceeded 16 microg/ml during continuous IV infusion. None of the dogs developed adverse effects. CONCLUSIONS AND CLINICAL RELEVANCE: Administration of ceftazidime subcutaneously (30 mg/kg, q 4 h) or as a constant IV infusion (loading dose, 4.4 mg/kg; rate, 4.1 mg/kg/h) would maintain serum ceftazidime concentrations above the MIC determined for 101 clinical isolates of P aeruginosa. Use of these dosages may be appropriate for treatment of dogs with infections caused by P aeruginosa.  相似文献   

20.
The minimum inhibitory concentrations (MICs) of tetracycline, enrofloxacin, tylosin, spiramycin and a lincomycin:spectinomycin 1:2 combination, against 24 Sicilian isolates of Mycoplasma agalactiae, the causative organism of contagious agalactia were determined in vitro by a broth dilution method. Enrofloxacin was the most effective antimicrobial in vitro with a range of MIC values from 0.125 to 0.500 microg/ml and an MIC(50) of 0.203 and MIC(90) of 0.365 microg/ml. Using the MIC(50) and MIC(90) values the remaining four antimicrobials are ranked in order of in vitro effectiveness as follows: tylosin (MIC(50)0.292; MIC(90)0.525 microg/ml) was slightly more effective than tetracycline (MIC(50)0.296; MIC(90)0.533 microg/ml), followed by lincomycin:spectinomycin (MIC(50)0.521; MIC(90)0.938 microg/ml) and spiramycin (MIC(50)1.583; MIC(90)2.850 microg/ml). MIC values above 1.000 microg/ml were obtained using tetracycline, tylosin and spiramycin for some M. agalactiae isolates.  相似文献   

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