Prevalence of benzimidazole resistant nematodes in sheep flocks in Yucatan,Mexico

Thirty-eight sheep flocks, located in three municipalities in the Eastern Yucatan, Mexico, were surveyed for gastrointestinal nematodes resistant to benzimidazole (BZD) anthelmintics (AH). On each flock, 30 sheep were randomly distributed into two groups of 15 animals: albendazole group (5mg/kg BW) and untreated control group. Animals were refrained from any food (either browsing/grazing or supplement) for a period of 16 h prior to treatment. Faecal egg counts (FEC) and larval cultures were performed 10 days after anthelmintic treatment. Percentage reduction and 95% confidence intervals were determined. Anthelmintic resistance (AR) was declared when the percentage reduction in FEC was <95% and the 95% confidence interval was <90%. AR was suspected when only one of the two criteria was met. The survey indicated that AR occurred in 15.8% (n=6) (95% confidence interval=+/-11.6%) and was suspected in 23.7% of the farms (n=9) (95% confidence interval=+/-13.3%). Post-treatment larval cultures indicated that Haemonchus was the only resistant genus. The questionnaire survey showed that most farmers (92%) considered their sheep a secondary activity to cattle production. The majority of farmers (97.4%) treat their animals according to visual appreciation of weight. However, most farmers (79%) treat their flocks at very low frequencies (<3 times per year). Drug rotation was performed every 12 months or more by 84.2% of farmers. Anthelmintics used were: macrociclic lactones (47.4%), BZD (39.5%), levamisol (10.5%) and 1 farmer used closantel.     

Mechlorethamine, procarbazine and prednisone for the treatment of resistant lymphoma in dogs

Forty-one dogs with resistant lymphoma were treated with a modified MOPP (mechlorethamine, vincristine, procarbazine and prednisone) protocol (MPP [mechlorethamine, procarbazine and prednisone] administered on a 21-day cycle, shortened from the 28-day MOPP cycle). The overall response rate to MPP was 34% for a median of 56 days (95% confidence interval 30–238). Seventeen percent of dogs had a complete response for a median duration of 238 days, 17% had a partial response for a median of 56 days and 32% had stable disease for a median of 24 days. Histological grade or cell morphology on cytology was associated with response. Minimal toxicity was observed with the MPP protocol, suggesting that further dose intensification or addition of another chemotherapeutic agent would be possible.     

Glycopeptide resistant Staphylococcus

Insensitivity of Staphylococcus aureus to glycopeptides became known at the end of the 1990s. To distinguish intermediate (VISA and GISA) and full resistance (vancomycin-resistant Staphylococcus aureus, VRSA) is of both epidemiological and clinical importance. The VISA (GISA) phenotype is obviously selected by glycopeptide usage in individual patients and can be disseminated by clonal spread of particularly affected staphylococcal isolates, preferentially methicillin-resistant S. aureus (MRSA). In the meantime emergence of VISA became known worldwide. VRSA evolve by acquisition of the vanA gene from enterococci, which are of significance as reservoir of resistance genes among gram-positive bacterial pathogens. Until now three independent single cases of emergence of VRSA became known from the USA, in two of them an association with vanA containing Enterococcus spp. at the same site of the affected patients could be established. The frequency of VISA (GISA) among MRSA in Central Europe is still low (<0.1%); no VRSA have been detected until now.     

Evaluation of mechlorethamine,vinblastine, procarbazine,and prednisone for the treatment of resistant multicentric canine lymphoma

Multi-agent chemotherapy successfully induces remission in most naïve, high-grade canine lymphoma patients; however, disease recurrence is common. MOPP (mechlorethamine, vincristine, procarbazine, and prednisone) is an effective rescue protocol used to re-induce remission, but is associated with gastrointestinal toxicity and can be a less desirable option for patients that previously failed vincristine-containing protocols. Therefore, alternative members of the vinca alkaloid family, such as vinblastine, could be potentially advantageous as substitutes for vincristine to reduce gastrointestinal toxicity and chemoresistance. The objective of this study was to report the clinical outcomes and toxicity of 36 dogs with relapsed or refractory multicentric lymphoma treated with a modified MOPP protocol whereby vincristine was replaced with vinblastine (MVPP). The overall response rate to MVPP was 25% with a median progression free survival of 15 days and a median overall survival of 45 days. MVPP at the prescribed doses resulted in modest and transient clinical benefit, but was well tolerated with no treatment delays or hospitalizations secondary to side effects. Given the minimal toxicity, dose intensification could be considered to improve clinical responses.     

腹泻犊牛大肠杆菌血清型抗菌药物耐药性耐药基因鉴定及脉冲场凝胶电泳分型

本试验对2011年由哈尔滨周边地区采集的263份腹泻犊牛的肛拭子进行大肠杆菌的分离鉴定,并通过小鼠致病性试验鉴定出26株致病性大肠杆菌,用Kirby-Bauer法开展对12种药物的药敏试验,PCR检测了我国流行广泛的9种耐药基因,脉冲场凝胶电泳(PFGE)进行基因分型.检测结果,该地区主要流行的致病性血清型为O26、O78和O15,所有致病性菌株都存在多重耐药现象,其中阿莫西林-棒酸、链霉素、四环素、复方新诺明的耐药率达到了100％,共检出7种耐药基因,检出率符合我国平均分布趋势,且检出率基本上与耐药表型相一致.PFGE结果显示,该地区存在致病性菌株的克隆传播.     

肉鸡屠宰加工生产链中沙门菌耐药基因检测与耐药性分析

利用聚合酶链式反应(PCR)扩增整合酶基因intⅠ检测沙门菌中Ⅰ类整合子携带率及可变区耐药基因盒并从β-内酰胺类、磺胺类、氨基糖苷类、喹诺酮类和酰胺醇类等5类抗生素的15种耐药基因进行检测,微量肉汤稀释法(MIC法)测定菌株对8类13种抗菌药的敏感程度。结果显示:肉鸡屠宰加工生产链中分离的沙门菌共检测12种耐药基因,未检测到β-内酰胺类的blaoxA-1group、blapse-1、四环素类的tetB和tet X基因。其中,以耐药基因catⅠ的检出率最高,87%(59/68);其次是tet G,检测率是85%(58/68);blatem耐药基因69%(47/68)。69%(47/68)的沙门菌检测出第Ⅰ类整合子。PCR扩增Ⅰ类整合子耐药基因盒,检测率为73%(35/47),扩增产物大小为1 009,1 664bp,携带aadA5、dfrl7和aadA2耐药基因,可分别介导对氨基糖苷类抗生素壮观霉素、链霉素和磺胺类药物甲氧苄氨嘧啶的耐药。68株菌中对AM的耐药率最高,多重耐药(≥2)菌株高达85%。结果表明:肉鸡屠宰加工生产链中沙门菌检测到较高的耐药基因及整合子携带率,对常见抗生素具有不同程度的耐药性,且耐药基因在耐药药敏试验结果与耐药基因的检测结果具有一致性。     

Isolation of oxfendazole resistant Cooperia oncophora in cattle

A field strain of Cooperia oncophora resistant to oxfendazole was isolated from a commercial cattle rearing property in Waikato, New Zealand. Resistance to oxfendazole was assessed by means of a faecal egg count depression test and an in vitro egg hatch test. This is the first documented case of anthelmintic resistance in Cooperia spp. and the first report of anthelmintic resistance in cattle in New Zealand.     

体外诱导和临床分离多重耐药大肠杆菌acrA和acrB基因无突变

临床分离的动物源性大肠杆菌的多重耐药株不断增多,多重耐药常与大肠杆菌外输泵有关,acrAB是最主要的外输泵.     

Prevalence of anthelmintic resistant nematodes in sheep in south-east England

The prevalence of anthelmintic resistant nematodes among 52 commercial flocks in south-east England was investigated by comparing the faecal egg counts of groups of lambs before, and seven days after, treatment with thiabendazole and levamisole. Evidence of thiabendazole resistance was found on seven farms. in each case Haemonchus contortus was the only species of nematode involved. In vitro egg hatch assays carried out for isolates from these farms gave ED50 estimates of 0.065 to 0.332 micrograms thiabendazole/ml compared with estimates of 0.027 to 0.031 micrograms thiabendazole/ml for a known susceptible strain of H contortus assayed at the same time. In a series of slaughter trials, there was a 17 to 85 per cent reduction, as compared with controls, in the mean worm burdens of groups of lambs infected with these isolates and killed seven days after treatment with thiabendazole, confirming their resistance to this anthelmintic.