Antimicrobial susceptibilities of Mycoplasma isolated from bovine mastitis in Japan

Mycoplasma spp. are highly contagious pathogens and intramammary Mycoplasma infection is a serious issue for the dairy industry. As there is no effective vaccine for Mycoplasma infection, control depends on good husbandry and chemo‐antibiotic therapy. In this study, antimicrobial susceptibility of Mycoplasma strains recently isolated from cases of bovine mastitis in Japan was evaluated by minimum inhibitory concentration (MIC). All Mycoplasma bovis strains were sensitive to pirlimycin, danofloxacin and enrofloxacin, but not kanamycin, oxytetracycline, tilmicosin or tylosin. M. californicum and M. bovigenitalium strains were sensitive to pirlimycin, danofloxacin, enrofloxacin, oxytetracycline, tilmicosin and tylosin, but not to kanamycin. This is the first report to describe the MIC of major antimicrobial agents for Mycoplasma species isolated from bovine mastitis in Japan.     

抗菌药物联合使用对耐达氟沙星鸡毒支原体的体外抑制作用研究

为探究抗菌药物联合使用对耐达氟沙星鸡毒支原体的体外抑制效果,选择鸡毒支原体标准株S6和对达氟沙星MIC升高程度不同的突变株M1、M2和M4,分别测定泰乐菌素、大观霉素、林可霉素、泰妙菌素、替米考星和多西环素种对4株鸡毒支原体的最低抑菌浓度,并使用达氟沙星分别联合上述6种抗菌药物进行体外抑菌试验.结果显示:除达氟沙星外,...     

A systematic review of sevoflurane and isoflurane minimum alveolar concentration in domestic cats

ObjectiveThe purpose of this systematic review is to summarize the results of studies which have determined the minimum alveolar concentration (MAC) of isoflurane and sevoflurane in domestic cats.Study DesignSystematic review.AnimalsCats.Methods usedA comprehensive search of research literature was performed without language restriction. The search utilized the Pubmed, Google Scholar, and CAB Abstracts electronic databases using a combination of free text terms ‘Minimum alveolar concentration’, ‘sevoflurane’, ‘isoflurane’, ‘anesthetic’, ‘cat’, ‘cats’ or ‘feline’. The search was conducted from November 2010 to June 2012.ResultsThe MAC for isoflurane ranged from 1.20 ± 0.13% to 2.22 ± 0.35% and the MAC for sevoflurane ranged from 2.5 ± 0.2% to 3.95 ± 0.33%. The average MAC for isoflurane was 1.71 ± 0.07% and for sevoflurane was 3.08 ± 0.4%.Conclusions &; Clinical RelevanceThe average MAC for isoflurane was 1.71 ± 0.07% and for sevoflurane was 3.08 ± 0.4%. Methodology differed among studies, and particular attention should be paid in the future to appropriate reporting of methods to allow sound conclusions to be made from the results.     

1株鸡毒支原体的分离鉴定及体外敏感中药的筛选

本研究旨在对山东泰安地区鸡毒支原体的流行菌株进行分离培养及鉴定和纯化,并针对该分离株筛选体外敏感的中药,为后续进一步研究提供材料。采用液体培养法与固体培养法从病鸡组织样品中分离、培养和纯化鸡毒支原体,并通过瑞士染色和姬姆萨染色、血清学方法及分子生物学方法对分离株进行初步鉴定,在此基础上,采用微量稀释法测定8种中药对分离菌株的最小抑菌浓度（MIC）,从而筛选到对分离菌株敏感的中药。结果显示,分离菌株在鸡毒支原体液体培养基中增殖后,培养基颜色由红变黄且呈半透明状态,在固体培养基中培养后呈典型的"煎蛋"样儿菌落,均符合鸡毒支原体培养特性;瑞士染色和姬姆萨染色结果显示,菌体形态符合鸡毒支原体的特征;血清学鉴定结果显示,分离株与鸡毒支原体阳性血清发生凝集;分子生物学鉴定结果显示,所扩增的核酸序列与鸡毒支原体匹配度高达99%;MIC测定结果显示,中药黄连和黄柏对分离的鸡毒支原体的抑菌活性较强,属敏感范畴,其MIC分别为≤0.98和0.39 mg/mL,而中药金荞麦和鱼腥草对鸡毒支原体中度敏感,MIC均≥125 mg/mL,板蓝根、白鲜皮、当归、艾叶对鸡毒支原体均不敏感。综上所述,本研究成功分离到1株鸡毒支原体,并且筛选出4种对该菌株敏感的中药,分别为黄连、黄柏、金荞麦和鱼腥草,为后期进一步研究防治鸡毒支原体病的中药组方时提供参考依据。     

三种抗菌药体外对鸡败血支原体的敏感性

本研究测定了蒽诺沙星、泰乐菌素及土霉素对鸡败血支原体（BG44T株）的体外最小抑菌浓度（MIC）及泰乐菌素与土霉素的联合药敏作用。MIC测定采用试管两倍稀释法，联合药敏采用棋盘法，重复三次试验，以平均值作为结果。蒽诺沙星、泰乐菌素及土霉素对鸡败血支原体的MIC分别为0.025μg/ml、0.00625μg/ml和0.5μg/ml。泰乐菌素与土霉素的联合药敏试验的抑菌浓度指数为0.5，合用有协同作用。     

恩诺沙星与其他抗菌药对鸡毒支原体的体外联合抑菌试验

采用2倍稀释法测定了恩诺沙星及其他8种抗菌药对鸡毒支原体BG44T株的最小抑菌浓度（MIC）,再以棋盘法测定恩诺沙星分别与其他8种抗菌药不同联合对鸡毒支原体BG44T株的敏感性。结果显示：恩诺沙星、替米考星、泰乐菌素、吉他霉素、林可霉素、沃尼妙林、泰妙菌素、氯霉素及氟苯尼考对鸡毒支原体BG44T株的MIC分别为0．063、0．004、0．016、0．063、16、〈0．004、0．008、8、8μg／mL。在8种不同联合用药对鸡毒支原体BG44T株的药敏试验中,恩诺沙星＋替米考星、恩诺沙星＋泰乐菌素、恩诺沙星＋吉他霉素、恩诺沙星＋林可霉素、恩诺沙星＋沃尼妙林、恩诺沙星＋泰妙菌素联合表现出相加作用,恩诺沙星＋氯霉素、恩诺沙星＋氟苯尼考表现出拮抗作用。     

牛支原体药物敏感性试验

为了解牛支原体的体外药敏试验,以指导临床合理使用抗生素,对临床分离鉴定的3株牛支原体,采用微量稀释法测定其对环丙沙星、恩诺沙星、红霉素和诺氟沙星的最低抑菌浓度(MIC),重复3次,取平均值。结果表明,牛支原体对环丙沙星的MIC抑菌范围为64μg/mL～128μg/mL,对恩诺沙星的MIC值为4μg/mL～8μg/mL,对红霉素的MIC值为2μg/mL～4μg/mL,对诺氟沙星的MIC值在8μg/mL～16μg/mL之间。牛支原体对红霉素的耐药性最低,其次是恩诺沙星、诺氟沙星,对环丙沙星的耐药性最高。     

Comparing the minimum inhibitory and mutant prevention concentrations of selected antibiotics against animal isolates of Pasteurella multocida and Salmonella typhimurium

Historically, the use of antibiotics was not well regulated in veterinary medicine. The emergence of antibiotic resistance (ABR) in pathogenic bacteria in human and veterinary medicine has driven the need for greater antibiotic stewardship. The preservation of certain antibiotic classes for use exclusively in humans, especially in cases of multidrug resistance, has highlighted the need for veterinarians to reduce its use and redefine dosage regimens of antibiotics to ensure efficacy and guard against the development of ABR pathogens. The minimum inhibitory concentration (MIC), the lowest concentration of an antibiotic drug that will prevent the growth of a bacterium, is recognised as a method to assist in antibiotic dosage determination. Minimum inhibitory concentrations sometimes fail to deal with first-step mutants in bacterial populations; therefore dosing regimens based solely on MIC can lead to the development of ABR. The mutant prevention concentration (MPC) is the minimum inhibitory antibiotic concentration of the most resistant first-step mutant. Mutant prevention concentration determination as a complementary and sometimes preferable alternative to MIC determination for veterinarians when managing bacterial pathogens. The results of this study focused on livestock pathogens and antibiotics used to treat them, which had a MIC value of 0.25 µg/mL for enrofloxacin against all 27 isolates of Salmonella typhimurium. The MPC values were 0.50 µg/mL, with the exception of five isolates that had MPC values of 4.00 µg/mL. The MPC test yielded 65.52% (18 isolates) Salmonella isolates with florfenicol MICs in the sensitive range, while 11 isolates were in the resistant range. Seventeen isolates (58.62%) of Pasteurella multocida had MIC values in the susceptible range and 41.38% (12 isolates) had an intermediate MIC value. Mutant prevention concentration determinations as done in this study is effective for the antibiotic treatment of bacterial infections and minimising the development of resistance. The MPC method can be used to better control to prevent the development of antibiotic drug resistance used in animals.     

新疆不同动物源大肠埃希菌耐药性比较

为了比较新疆不同动物源大肠埃希菌对临床常用抗菌药物的耐药情况,从猪场、羊场和牛场分别分离猪源大肠埃希菌454株、羊源大肠埃希菌638株和牛源大肠埃希菌89株,用微量肉汤法对上述细菌进行临床常用β-内酰胺类、氟喹诺酮类、氨基糖苷类和酰胺醇类抗菌药物最小抑菌浓度测定。结果表面,猪源大肠埃希菌对氨苄西林(67.0%)和阿莫西林/克拉维酸(63.7%)耐药率较高,其他药物耐药率在10.4%~41.2%之间;羊源大肠埃希菌对安普霉素(33.9%)和阿莫西林/克拉维酸(21.2%)耐药率较高,其他药物耐药率在3.1%~15.6%之间;牛源大肠埃希菌对氨苄西林(24.4%)和阿莫西林/克拉维酸(8.9%)耐药率较高,其他药物耐药率在1.1%~6.7%之间。多药耐药结果,猪源大肠埃希菌以2耐~5耐为主,羊源大肠埃希菌以0耐~2耐为主,牛源大肠埃希菌以0耐~1耐为主。新疆猪源大肠埃希菌对临床常用抗菌药物耐药情况最严重,羊源菌次之,牛源菌最轻;猪源大肠埃希菌多药耐药现象严重。     

宁夏地区牛支原体药物敏感性分析

[目的]提高牛支原体病治疗效果。[方法]应用微量肉汤稀释法对宁夏地区分离鉴定的74株牛支原体进行药物敏感性分析。[结果]恩诺沙星的MIC分布范围最小,MIC₅₀与MIC₉₀最小,其次是大观霉素、庆大霉素和卡那霉素;试验菌株对大观霉素的耐药率最低（12%）,其次为恩诺沙星（22%）,对庆大霉素和卡那霉素的耐药率最高且相同（36%）;肺分离株耐药性最强,关节液分离株次之,乳汁分离株最弱。[结论]恩诺沙星对牛支原体的体外抑菌效果最好,但易产生耐药性,应注意用药剂量和时长;肺分离株耐药性最强可能与呼吸道感染牛支原体的概率大且频繁使用抗生素有关。     

Effects of methadone on the minimum alveolar concentration of isoflurane in dogs

ObjectiveTo investigate the effects of methadone on the minimum alveolar concentration of isoflurane (ISO_MAC) in dogs.Study designProspective, randomized cross-over experimental study.AnimalsSix adult mongrel dogs, four males and two females, weighing 22.8 ± 6.6 kg.MethodsAnimals were anesthetized with isoflurane and mechanically ventilated on three separate days, at least 1 week apart. Core temperature was maintained between 37.5 and 38.5 °C during ISO_MAC determinations. On each study day, ISO_MAC was determined using electrical stimulation of the antebrachium (50 V, 50 Hz, 10 mseconds) at 2.5 and 5 hours after intravenous injection of physiological saline (control) or one of two doses of methadone (0.5 or 1.0 mg kg^?1).ResultsMean (±SD) ISO_MAC in the control treatment was 1.19 ± 0.15% and 1.18 ± 0.15% at 2.5 and 5 hours, respectively. The 1.0 mg kg^?1 dose of methadone reduced ISO_MAC by 48% (2.5 hours) and by 30% (5 hours), whereas the 0.5 mg kg^?1 dose caused smaller reductions in ISO_MAC (35% and 15% reductions at 2.5 and 5 hours, respectively). Both doses of methadone decreased heart rate (HR), but the 1.0 mg kg^?1 dose was associated with greater negative chronotropic actions (HR 37% lower than control) and mild metabolic acidosis at 2.5 hours. Mean arterial pressure increased in the MET1.0 treatment (13% higher than control) at 2.5 hours.Conclusions and clinical relevanceMethadone reduces ISO_MAC in a dose-related fashion and this effect is lessened over time. Although the isoflurane sparing effect of the 0.5 mg kg^?1 dose of methadone was smaller in comparison to the 1.0 mg kg^?1 dose, the lower dose is recommended for clinical use because it results in less evidence of cardiovascular impairment.     

The effect of buprenorphine on isoflurane minimum alveolar concentration in dogs

ObjectiveTo determine the effect of intravenous (IV) buprenorphine on the isoflurane (ISO) minimum alveolar concentration (ISOMAC) in dogs.Study designRandomized, crossover, design.AnimalsSix healthy, adult (2–3 years old), intact dogs (two males and four females) weighing 7.4–11.0 kg.MethodsEach dog was studied on three occasions, 1 week apart, and baseline ISOMAC (MAC_B) was determined on each occasion. ISOMAC was defined as the mean of the end-tidal ISO concentrations that prevented and allowed purposeful movement in response to a noxious stimulus. After MAC_B determination, dogs were randomly given buprenorphine (BUP) at either 0.01, 0.05 or 0.1 mg kg^?1 IV, and ISOMAC was determined at two time periods after BUP administration. The first post-treatment determination (MAC_T1) was initiated 45 minutes after BUP administration and the second determination (MAC_T2) was initiated 4 hours after BUP administration. MAC values were determined in duplicate and the mean values were used for statistical analysis.ResultsIsoflurane minimum alveolar concentration was decreased at 141 minutes (the time of MAC_T1 determination) by 25%, 35%, and 27% after administration of BUP at 0.01, 0.05, and 0.1 mg kg^?1, respectively (p ≤ 0.05). The MAC reductions were not statistically different among doses. The reductions in ISOMAC at 342 minutes (the time of MAC_T2 determination) ranged from 13 to 16%, and were not statistically different among doses.Conclusions and clinical significanceBuprenorphine at 0.01, 0.05, and 0.1 mg kg^?1 significantly decreased ISOMAC in dogs at 141 minutes but not at 342 minutes. When using BUP for MAC reduction re-dosing may be required for procedures of long duration, and there may be no advantage to using the 0.1 mg kg^?1 dose.     

Isoflurane minimum alveolar concentration sparing effects of fentanyl in the dog

Objective

To characterize the isoflurane-sparing effects of a high and a low dose of fentanyl in dogs, and its effects on mean arterial pressure (MAP) and heart rate (HR).

Microbial flora and antimicrobial susceptibility patterns from dogs with otitis media

This study evaluated the middle ear microbial flora and antimicrobial susceptibility patterns from dogs with otitis media. Antimicrobial susceptibility patterns were obtained on 164 micro-organisms from 107 ears of 82 dogs with otitis media that presented to Louisiana State University over a 12-year period. The most common micro-organisms isolated were Staphylococcus intermedius (26.8%), Pseudomonas aeruginosa (23.2%), β-haemolytic streptococcus (12.8%), Proteus spp. (11.0%) and Staphylococcus epidermidis (8.5%). Antimicrobial susceptibility testing was performed on all isolates employing the disk diffusion method (Kirby-Bauer). Minimum inhibitory concentration (MIC) testing for enrofloxacin and ciprofloxacin was performed on 10 of the 18 P. aeruginosa isolates found to be resistant to enrofloxacin on Kirby-Bauer. Of these isolates, 6 (60%) were susceptible, 1 (10%) was intermediate and 3 (30%) were resistant to enrofloxacin. Eight of these isolates (80%) were susceptible to ciprofloxacin, 1 (10%) showed intermediate susceptibility and 1 (10%) was resistant.     

Efficacy of phage therapy in pigs: systematic review and meta-analysis

Limits on the use and efficacy of various antibiotics coupled with negative consumer perception of the practice have together spurred substantial research into compounds that could reduce the use antibiotics to control bacterial diseases in pigs. Bacteriophages are often among such potential compounds, and various groups have examined the efficacy of bacteriophages or bacteriophage products in limiting transmission or colonization of targeted bacteria. The study presented here provides a systematic review of such studies followed by a meta-analysis of aggregated data produced by each study. The data set was limited to inputs (n = 19; 576 total observations) from studies where: 1) live pigs were inoculated with a known quantity of challenge bacteria; 2) challenged animals were treated with a known quantity of phages; 3) concentrations of the challenge bacteria were measured in different tissues/fluids following phage treatment; and 4) SD (or SE to allow calculation of SD) was reported. Concentrations of challenge bacteria were significantly lower in phage-treated pigs versus challenged but untreated pigs (P < 0.0001; effect size = −1.06 1log₁₀ colony-forming units [CFU]/g). The effect size of phage treatment was significantly greater (P < 0.05) in samples collected 48 to 96 h following phage treatment versus those collected ≤ 24 h following phage treatment. Likewise, effect size of phage treatment was significantly greater in piglets versus market-weight pigs. Across observations, phage treatment effect sizes were greatest (P < 0.01) in fecal samples versus ileal or cecal samples. Taken together, these data indicate that phage treatment can significantly reduce the concentrations of targeted bacteria in pigs; scenarios exist, however, where phage treatment could predictably be more or less effective.     

9种抗菌药物对大肠埃希菌最小抑菌浓度的测定

畜禽养殖中会用到一些抗菌药物,而药物选用需要进行药物敏感性试验,目前市售的药敏纸片多为人用抗菌药物,为了制备兽用抗菌药物的药敏纸片,需要对药物的最小抑菌浓度(MIC)进行测定。该研究筛选了国家兽用药物名录中规定的、兽医临床上常用6类共9种抗菌药物(头孢噻呋钠、硫酸链霉素、强力霉素、土霉素、氨苄西林、氟苯尼考、替米考星、硫酸新霉素、青霉素),以大肠埃希菌为指标菌,通过微量肉汤稀释法分别测定了9种常用抗菌药物的最小抑菌浓度(MIC)。结果表明,头孢噻呋钠、硫酸链霉素、强力霉素、土霉素、氨苄西林、氟苯尼考、替米考星、硫酸新霉素、青霉素对指标菌的MIC值分别为为2、4、4、16、8、16、64、32、250μg/mL。研究结果为这些药物的临床应用和药敏纸片的研制提供了基础资料。     

Effects of tramadol on the minimum alveolar concentration of sevoflurane in dogs

ObjectiveTo evaluate the effect of tramadol on sevoflurane minimum alveolar concentration (MAC_SEVO) in dogs. It was hypothesized that tramadol would dose-dependently decrease MAC_SEVO.Study designRandomized crossover experimental study.AnimalsSix healthy, adult female mixed-breed dogs (24.2 ± 2.6 kg).MethodsEach dog was studied on two occasions with a 7-day washout period. Anesthesia was induced using sevoflurane delivered via a mask. Baseline MAC (MAC_B) was determined starting 45 minutes after tracheal intubation. A noxious stimulus (50 V, 50 Hz, 10 ms) was applied subcutaneously over the mid-humeral area. If purposeful movement occurred, the end-tidal sevoflurane was increased by 0.1%; otherwise, it was decreased by 0.1%, and the stimulus was re-applied after a 20-minute equilibration. After MAC_B determination, dogs randomly received a tramadol loading dose of either 1.5 mg kg^?1 followed by a continuous rate infusion (CRI) of 1.3 mg kg^?1 hour^?1 (T1) or 3 mg kg^?1 followed by a 2.6 mg kg^?1 hour^?1 CRI (T2). Post-treatment MAC determination (MAC_T) began 45 minutes after starting the CRI. Data were analyzed using a mixed model anova to determine the effect of treatment on percentage change in baseline MAC_SEVO (p < 0.05).ResultsThe MAC_B values were 1.80 ± 0.3 and 1.75 ± 0.2 for T1 and T2, respectively, and did not differ significantly. MAC_T decreased by 26 ± 8% for T1 and 36 ± 12% for T2. However, there was no statistically significant difference in the decrease between the two treatments.Conclusion and clinical relevanceTramadol significantly reduced MAC_SEVO but this was not dose dependent at the doses studied.     

GABA(A) receptor antagonism increases NMDA receptor inhibition by isoflurane at a minimum alveolar concentration

ObjectiveAt the minimum alveolar concentration (MAC), isoflurane potentiates GABA_A receptor currents and inhibits NMDA receptor currents, and these actions may be important for producing anesthesia. However, isoflurane modulates GABA_A receptors more potently than NMDA receptors. The objective of this study was to test whether isoflurane would function as a more potent NMDA receptor antagonist if its efficacy at GABA_A receptors was decreased.Study designProspective experimental study.AnimalsFourteen 10-week-old male Sprague–Dawley rats weighing 269 ± 12 g.MethodsIndwelling lumbar subarachnoid catheters were surgically placed in isoflurane-anesthetized rats. Two days later, the rats were anesthetized with isoflurane, and artificial CSF containing either 0 or 1 mg kg^?1 picrotoxin, a GABA_A receptor antagonist, was infused intrathecally at 1 μL minute^?1. The baseline isoflurane MAC was then determined using a standard tail clamp technique. MK801 (dizocilpine), an NMDA receptor antagonist, was then administered intravenously at 0.5 mg kg^?1. Isoflurane MAC was re-measured.ResultsPicrotoxin increased isoflurane MAC by 16% compared to controls. MK801 significantly decreased isoflurane MAC by 0.72% of an atmosphere in controls versus 0.47% of an atmosphere in rats receiving intrathecal picrotoxin.Conclusions and clinical relevanceA smaller MK801 MAC-sparing effect in the picrotoxin group is consistent with greater NMDA antagonism by isoflurane in these animals, since it suggests that fewer NMDA receptors are available upon which MK801 could act to decrease isoflurane MAC. Decreasing isoflurane GABA_A potentiation increases isoflurane NMDA antagonism at MAC. Hence, the magnitude of an anesthetic effect on a given channel or receptor at MAC may depend upon effects at other receptors.     

Anaesthetic potency of isoflurane in cattle: determination of the minimum alveolar concentration

Objective To determine the minimum alveolar concentration (MAC) of isoflurane in cattle.
Study design Prospective study.
Animals Sixteen healthy adult female Holstein-Friesian cattle weighing 612 ± 17 kg (× ± SEM) and aged 5.7 ± 0.9 years old.
Methods The unsedated cattle were restrained in right lateral recumbency using a rope harness technique. Anaesthesia was induced with isoflurane (ISO) in oxygen via a face mask connected to a large-animal, semiclosed anaesthetic circle system. Each cow was intubated with a cuffed orotracheal tube (25 mm ID). Inspired and end-tidal ISO were monitored using a calibrated infra red analyser with a methane filter. The MAC of ISO that prevented gross purposeful movement in response to a tail and dewclaw clamp was determined. The time from the start of ISO administration to intubation, the time interval between discontinuance of ISO and the time the animal regained sternal recumbency, were recorded. Time to standing and quality of recovery were also recorded.
Results The time from the start of ISO administration to tracheal intubation was 18.68 ± 2.77 minutes. The MAC of ISO in these cattle was 1.27 ± 0.03% (1.14 ± 0.01% corrected to sea level). Time to sternal recumbency after 90 ± 16 minutes of anaesthesia from intubation was 4.60 ± 0.58 minutes and time to standing was 6.70 ± 1.02 minutes. All cattle were extubated when they regained sternal recumbency.
Conclusion The MAC of isoflurane in these cattle was 1.27 ± 0.03% (1.14 ± 0.01% corrected to sea level). ISO provided a smooth induction to, and rapid recovery from, anaesthesia.
Clinical relevance Knowledge of the MAC of ISO in cattle will facilitate its appropriate clinical use.