Preliminary study on the use of ceftazidime, a broad spectrum cephalosporin antibiotic, in snakes

Ceftazidime, a broad spectrum cephalosporin antibiotic with an enhanced anti-pseudomonal activity, was tested in vitro against a variety of reptilian bacterial isolates. Blood concentrations of this antibiotic were determined in clinically ill snakes following an intramuscular injection at a dose rate of 20 mg kg-1. Peak plasma levels of up to 70.5 micrograms ml-1 were reached one to eight hours after the injection and therapeutic plasma levels were maintained for at least 96 hours. A series of snakes treated with ceftazidime at a dose rate of 20 mg kg-1 every 72 hours showed a rapid and obvious clinical response to treatment. The snakes were maintained at 30 degrees C during treatment and the effect of environmental temperature on antibiotic half-life is discussed. Ceftazidime proved to be a highly active antibiotic against the bacteria known to cause disease in reptiles, with no obvious adverse effects having been so far described.     

抗生素替代物的现状和远景(3)

6用饲料添加剂替代抗生素 6．1抗生素改变肠道微生物区系 抗生素用做家禽、猪及其他家畜的生长促进剂已有多年。抗生素的好处包括在特定条件下降低下痢发病频率，改善体重和饲料转化率，提高存活率，以及在许多场合可改进加工性状，如由于良好的肠道健康及消化导致的胴体或胸肉产出量的增加。肠道细菌种群的改变和细菌与宿主之间的相互作用可解释抗生素的上述作用。     

抗生素替代物的现状和远景(4)

6.2.5植物精油和香料提取物在欧洲,这些产品已应用了约10年之久,目前已为其他国家采用。下列的产品可作为这种类型制品的例子,这类产品的实例有:包括CRINAPOULTRY复合物(瑞士Gland的CRINA S.A.公司),Orego-Stim(英国Cranfield的Meriden AnimalHealth公司),AEN(法国Saint-Bonnet     

抗生素替代物的现状和远景(2)

3 特殊的营养添加剂 当抗生素从饲料撤除时．有许多拥有非凡益处的营养添加剂可以使用。这些添加其中的一部分包括：甜菜碱、铜源、带残液的干烧酒糟、发酵副产品、25-羟基-胆钙化醇（25-羟基-维生素D3，）、无氯化钠和钾（碳酸氢钠，碳酸钾）的添加剂、整粒小麦和氧化锌（猪）。     

The multiple antibiotic resistance (mar) locus and its significance

Chromosomally encoded systems involved in low level resistance of bacteria to different classes of antibiotics (mainly beta-lactams, chloramphenicol, quinolones and tetracycline), disinfectants and in resistance to organic solvents have been the focus of considerable interest in recent years. The multiple antibiotic resistance (mar) locus of Escherichia coli and Salmonella is perhaps the best described system involved in this type of resistance which is induced by MarA, the activator protein encoded by the marRAB locus. The mar -locus is reported to mediate resistance primarily by up-regulating efflux of some antibiotics, disinfectants and organic solvents via the AcrAB-TolC efflux pump and down regulating influx through Outer Membrane Protein F (OmpF). Whilst the level of antibiotic resistance conferred by marRAB is only low level, there are increasing data to suggest that marRAB and related systems are important in clinical antibiotic resistance, possibly as a 'stepping stone' to higher levels of resistance. Other related systems include up-regulation of RobA, SoxS and AcrAB which give rise to a similar resistance phenotype to that conferred by up-regulation of MarA. The aim of this paper is to review the function and significance of the mar -locus and related systems with a particular focus on its implications in veterinary medicine.     

抗生素替代物的现状和远景(1)

1抗生素的谨慎利用如今,出口家禽产品所需要的饲料和管理标准,不是由家禽或禽蛋的生产国、而是由出口目标国或行销国来决定。例如,如果巴西的鸡向日本或欧洲出口,就必须用日本和欧洲的规格,而不是巴西的要求。在巴西,生产用于当地消费的鸡时,主要使用廉价的抗生素,而用于出口的     

Epidemiology of extended spectrum beta-lactamase E. coli (CTX-M-15) on a commercial dairy farm

The epidemiology of an extended spectrum beta-lactamase Escherichia coli (CTX-M-15) was observed and described on a commercial dairy farm located in the United Kingdom. During 2008 longitudinal sampling of faecal pat samples from different cattle groups comprising milking and non-milking cows, calving cows, calves, and the environment was carried out. The proportion of CTX-M-15 E. coli positive samples was significantly (p<0.0.01) higher in milking cows (30.3%, CI(95%) 26.8; 33.8) than in the herd as a whole (17.0%, CI(95%) 14.9; 19.0). In 2008 95.6% of sampled calves tested positive for CTX-M-15 E. coli at two days of age. A more detailed investigation in 2009 revealed that cows and heifers were approximately eight times more likely to test positive in the 10 days after calving than the 9 days before (OR 7.6, CI(95%) 2.32; 24.9). The CTX-M15 E. coli was also readily isolated from the immediate calving pen environment, including the water troughs. A cyclic pattern was apparent where cows immediately after calving and as high yielders were highly positive, but where the prevalence decreased during the dry period. The increased prevalence of the CTX-M-15 E. coli in certain cattle groups and farm environments including calving pens suggested that husbandry, antimicrobial usage and hygiene may play a significant role on a farm with regards to the epidemiology of CTX-M-15. This may offer a practical opportunity to reduce further dissemination through good practice and hygiene around calving.     

Epizootic rabbit enteropathy inoculum (TEC4): antibiograms and antibiotic fractionation

Epizootic rabbit enteropathy (ERE) emerged and spread in Europe within the last 13 years causing major economical loss. The aims of the study was to evaluate antibiograms of TEC4, an inoculum composed of an extract of intestinal content of affected rabbits, and to test the potential of different antibiotic-based TEC4 fractions to reproduce the disease. Twenty nine different antibiotic discs were incubated for determining bacteria resistance. In a complementary study, nine tubes of liquid medium were inoculated with TEC4, incubated and added individually with amoxicillin/clavulanic acid, bacitracin, ceftiofur, doxycycline, novobiocin, streptomycyin, tylosin, vancomycin and 0.9% saline solution as control. The content of each tube was washed by centrifugation and suspended in saline. The three most effective antibiotics are florfenicol, amoxycillin/clavulanic acid and tylosin. A high concentration of Clostridium sordelli and Bacillus firmus were isolated in all fractions. Species never cultured from TEC4 were identified as Fusobacterium necrogenes (in vancomycin fraction), Cellulomonas sp (in novobiocin fraction) and Bacteroides distasonis (in doxycycline fraction). The ERE was reproduced when bacitracin, doxycycline and 0.9% fractions were inoculated. Rabbits showed ERE clinical signs with the specific drop in daily weight gain.     

The resistance spectrum shown by a fenvalerate-resistant strain of blue tick (Boophilus decoloratus) to a range of ixodicides

A strain of Boophilus decoloratus, resistant to fenvalerate, was subjected to larval immersion, adult immersion and stall tests using the following classes of ixodicides: organochlorines, organophosphates, a diamidide and pyrethroids. A susceptible reference strain of B. decoloratus was used for comparative purposes. The results indicated a high level of resistance to DDT and camphechlor, slight tolerance to dioxathion, chlorfenvinphos and pirimiphos ethyl, full susceptibility to bromophos ethyl and amitraz, but marked resistance to cyhalothrin, cypemethrin, deltamethrin and flumethrin. This marked resistance in the strain therefore appears to be widespread within the pyrethroid group of chemicals and may have developed as a result of organochlorine cross-resistance.     

甘露寡糖-抗生素生长促进剂的天然替代品

1抗生素生长促进剂发展现状抗生素长期以来被用于治疗人类和养殖场动物的疾病。大约50年前,美国食品和药物管理局(FDA)批准在饲料中添加亚治疗剂量或低剂量的抗生素来帮助动物生长得更快,产出更多的肉和预防疾病。随着抗生素在动物和人类中使用的日益增多,细菌对一些在人类和动     

Effect of a new macrolide antibiotic (tilmicosin) on pneumonia experimentally induced in calves by Mycoplasma bovis and Pasteurella haemolytica

Two gnotobiotic calves were treated once with tilmicosin (20 mg kg-1) six hours before they were infected by the intratracheal route with Mycoplasma bovis and Pasteurella haemolytica serotype 1. This treatment prevented colonisation of the lungs by P haemolytica and considerably reduced colonisation by M bovis, and the clinical scores and the extent of pneumonic consolidation, compared with two untreated gnotobiotic calves, both of which had to be killed in extremis for humanitarian reasons within 24 hours of infection. In a second experiment, 10 conventionally reared calves were similarly exposed to infection and, at the onset of clinical disease, five were treated once with tilmicosin (20 mg kg-1). Colonisation by P haemolytica and M bovis, the clinical scores and extent of pneumonic consolidation were suppressed or greatly reduced in the treated compared with the untreated calves, one of which had to be killed in extremis two days after infection. It was concluded that tilmicosin had a beneficial effect.     

兽医临床超广谱β-内酰胺酶的表型检测方法

β-内酰胺环类抗生素自上世纪60年代研制以来，一直广泛应用，目前占全球抗生素消量的50％，但近年来耐药菌株的出现使它们的使用受到严重威胁。研究显示，细菌对第三代头孢菌素的耐药主要是因为产生了能水解该类扰生素的超广谱β-内酰胺酶（Extend spectrum β-lactamses，ESBLs）。ESBLs大多是质粒介导的β-内酰胺酶，主要由大肠埃希氏菌与肺炎克雷伯菌产生，由于其能降低新的广谱头孢菌素的功效，造成体外药敏试验敏感而体内用药无效，严重影响β-内酰胺环类抗生素的疗效。     

Use of antibiotic impregnated polymethylmethacrylate beads for the treatment of chronic mandibular osteomyelitis in a Bennett's wallaby (Macropus rufogriseus rufogriseus)

Antibiotic impregnated polymethylmethacrylate beads were surgically implanted into the mandible of an adult Bennett's wallaby (Macropus rufogriseus rufogriseus) suffering from chronic mandibular osteomyelitis that had proven refractory to systemic antibiotic treatment. Although a discrete inflammatory mass remained, clinical signs of inappetance and a discharging sinus were alleviated following implantation of the beads. This procedure resulted in a more satisfactory outcome than other methods of treatment used previously for this condition and avoided the problems associated with regular handling and prolonged medication.     

Broad spectrum antimicrobial activity of leukocyte extracts from the American alligator (Alligator mississippiensis)

Leukocytes were isolated from whole blood of wild alligators by differential sedimentation. The leukocytes were disrupted in 5% AcOH and the crude extracts processed by ultrafiltration. The extracts were subjected to solvent exchange (0.1% AcOH) and the fraction that contained macromolecules between 1 and 10 kDa were subjected to further analyses. The acid extracts of the alligator leukocytes exhibited substantial antimycotic activities against six of eight species of Candida yeast tested. In addition, the alligator leukocyte extracts were effective as antimicrobial agents against 10 of 12 bacterial species, and displayed moderate activity against two enveloped viruses (human immunodeficiency virus-1 and herpes simplex virus-1_HF). Kinetic analyses revealed that the antimycotic effects of the leukocyte extract occurred rapidly, with 64% fungal growth inhibition within 3 min of exposure. The molecule(s) responsible for the antimicrobial activities were sensitive to proteases, heat-stable, acid soluble, and in the 1–10 kDa range. These data suggest that alligator leukocytes express cationic peptides that are responsible for their antimicrobial properties.     

Changes in antibiotic resistance in equine bacterial ulcerative keratitis (1991-2000): 65 horses

Objective To document changes in antibiotic resistance of organisms in cases of equine bacterial ulcerative keratitis over a 10‐year time period. Design A retrospective study. Participants Medical records of equine patients with bacterial ulcerative keratitis seen at the University of Florida's VMTH for the years 1991–2000 were reviewed. Materials and methods All cases of equine bacterial ulcerative keratitis for the above mentioned years were examined. Bacterial isolates were identified and subjected to Kirby‐Bauer disc diffusion method sensitivity tests. Antibiotics used in the sensitivity tests included bacitracin, ampicillin, gentamicin, chloramphenicol, polymyxin B, trimethoprim‐sulfa, neomycin, kanamycin, carbenicillin, tobramycin and enrofloxacin. Results A total of 65 bacterial isolates were subjected to sensitivity testing. Of these isolates, Pseudomonas aeruginosa accounted for 14 of the bacterial isolates (22%), Streptococcus equi subspecies zooepidemicus accounted for 13 of the bacterial isolates (20%), and Staphylococcus aureus accounted for four of the isolates (6%). A statistically significant increase in resistance of Pseudomonas aeruginosa isolates to the antibiotics gentamicin and tobramycin was found between the isolates from 1992 to 1998 and those from 1999 to 2000. An increase in resistance of Streptococcus equi subspecies zooepidemicus to gentamicin was found between the isolates from 1993 to 1997 and those from 1998 to 2000. Conclusions Streptococcus equi subspecies zooepidemicus and Pseudomonas aeruginosa were the most common organisms isolated from cases of equine bacterial keratitis referred to the University of Florida's VMTH for the years 1991–2000. There appears to be an increase in resistance of Streptococcus equi subspecies zooepidemicus to gentamicin over the past 10 years. In addition, there is a significant increase in resistance of Pseudomonas aeruginosa to both gentamicin and tobramycin over the same time period.     

In vitro evaluation of antibiotic elution from polymethylmethacrylate (PMMA) and mechanical assessment of antibiotic-PMMA composites

OBJECTIVE: To determine whether different methods of sterilization of antibiotic vials or the heat of polymerization altered the antimicrobial activity or mechanical properties of antibiotic/polymethylmethacrylate (PMMA) composites when compared to antibiotic-free PMMA. STUDY DESIGN: In vitro study. METHODS: Steam-sterilized, gas-sterilized, and non-sterilized 1 gram vials of cefazolin and injectable gentamicin sulfate (high and low doses) were mixed with PMMA to prepare composites for antibiotic elution evaluation, compression, and elongation testing. Blocks of PMMA that contained antibiotic were assayed for antibacterial activity using an agar gel diffusion method or were placed in phosphate buffered saline (PBS) to assess elution of antibiotic. Phosphate buffered saline samples from steam-sterilized cefazolin and high-dose gentamicin groups were assayed on days 1, 2, 5, and 9 for cefazolin or gentamicin concentration by high-pressure liquid chromatography or fluorescent polarization immunoassay, respectively. RESULTS: PMMA blocks containing antibiotic inhibited bacterial growth of Staphylococcus aureus 25923 for an average of 9 days. Cefazolin and gentamicin concentration in PBS decreased dramatically after the first 24 hours, but remained above minimum inhibitory concentration (MIC) throughout the experiment for all groups except low-dose gentamicin. Compressive strength of plugs made from plain cement and plugs made from PMMA mixed with untreated and steam-sterilized cefazolin was similar, but was significantly different from the other groups. There appeared to be an inverse relationship between compressive strength and elongation. CONCLUSION: PMMA/antibiotic composites inhibited bacterial growth for 7 to 10 days. Compressive strength was affected by different additions of antibiotic. CLINICAL RELEVANCE: Bacteria introduced during a surgical procedure may be inhibited by elution of antibiotic from PMMA at the time of contamination.     

新一代驱虫抗生素--莫西菌素

本文综述了莫西菌素的理化特性、作用机制、药效学、药动学、制剂、毒性、残留及耐药性等，并与伊维菌素进行了对比。