内蒙古呼和浩特及包头地区牛乳房内感染葡萄球菌的药敏试验

对内蒙古呼和浩特和包头地区4个奶牛场或养牛集中区20株已鉴定的奶牛乳房内感染葡萄球菌进行了药敏试验.试验菌株普遍对头孢噻吩、庆大霉素、妥布霉素、新霉素、四环素、氯霉素、洁霉素、红霉素、诺氟沙星、环丙沙星、新生霉素高度敏感.从使用青霉素类频繁的牛场分离到的菌株对青霉素G和氨苄青霉素不敏感.     

内蒙古呼和浩特及包头地区牛乳房内感染葡萄球菌的药敏试验

对内蒙古呼和浩特和包头地区4个奶牛场或养牛集中区20株已鉴定的奶牛乳房内感染葡萄球菌进行了药敏试验。试验菌株普遍对头孢噻吩、庆大霉素、妥布霉素、新霉素、四环素、氯霉素、洁霉素、红霉素、诺氟沙星、环丙沙星、新生霉素高度敏感。从使用青霉素类频繁的牛场分离到的菌株对青霉素G和氨苄青霉素不敏感。     

秃鹫黏质沙雷氏菌和大肠杆菌的分离、鉴定及药敏试验

采集死亡秃鹫的心脏、肝脏病灶进行细菌分离鉴定、生化试验,其病原菌为沙雷氏菌和大肠杆菌;经药敏试验,大肠杆菌对环丙沙星、庆大霉素、氯霉素极度敏感,对头孢哌酮、头孢他啶、头孢吡肟高度敏感,对恩诺沙星中度敏感,对新生霉素、多黏菌素B、四环素低度敏感;黏质沙雷氏菌对头孢哌酮、头孢他啶、恩诺沙星高度敏感,对头孢吡肟、环丙沙星中度敏感,对庆大霉素、氯霉素、新生霉素、多黏菌素B、四环素低度敏感。采用对黏质沙雷氏菌和大肠杆菌均属高度敏感的药物头孢哌酮治疗患病秃鹫,陆续痊愈。     

奶牛乳房炎溶血性病原菌分离培养及药敏试验

为了掌握大通县某奶牛场引起奶牛乳房炎的主要致病菌及耐菌药物,无菌采集病牛乳样,进行细菌分离培养和细菌药敏试验。结果显示,该奶牛场奶牛乳房炎的主要致病菌为2种溶血性链球菌,即ɑ-溶血性链球菌和β-溶血性链球菌。两种致病菌对不同药物的敏感性不同,α-溶血性链球菌对阿莫西林、庆大霉素、红霉素、青霉素、先锋V号具有一定的耐药性,对氯霉素、四环素敏感性较高;β-溶血性链球菌对阿莫西林、庆大霉素、青霉素、红霉素、环丙沙星、先锋V号具有一定的耐药性,对氯霉素、四环素较敏感。     

鸭大肠杆菌的分离鉴定及药敏试验

从海口某种鸭场的病死鸭中分离得到疑似大肠杆菌的菌株,并对该菌株进行分离鉴定、生化试验和药敏试验。结果表明,分离菌对复方新诺明、环丙沙星、庆大霉素、多粘菌素B高度敏感,对红霉素中度敏感,而对氨苄青霉素、先锋霉素V、先锋孟多、头孢噻肟、克林霉素、四环素、强力霉素、氯霉素、万古霉素不敏感。说明该鸭场出现了耐药性的致病性大肠杆菌。     

大鲵致病性嗜水气单胞菌的分离鉴定与耐药性分析

为了研究从发病大鲵体内分离到的致病菌的生物特性与耐药性,试验采用细菌分离培养技术分离到1株致病菌,并对其进行了细菌分离鉴定、生化鉴定、药敏试验、动物致病试验。结果表明:该分离菌为嗜水气单胞菌,分离菌对小白鼠具有致病性;对头孢噻吩、庆大霉素、美福仙、左氟沙星、恩诺沙星高度敏感,对阿莫西林、链霉素、先锋霉素Ⅳ、卡那霉素、新霉素、丁胺卡那霉素、氯霉素、阿奇霉素中度敏感,对青霉素、四环素、洁霉素、红霉素不敏感。     

猪源绿色气球菌的分离鉴定及耐药性分析

为了解河北省保定市某猪场断奶仔猪发生以腹泻和呼吸道为主要症状的病死原因,无菌采集病料进行细菌分离培养、培养特性、生化特性鉴定,初步表明分离菌株为绿色气球菌。16S rRNA基因序列同源性比对分析显示,分离菌与绿色气球菌同源性达99.4%～100%。致病性试验证实2株分离菌株有致病性。分离菌株仅对氨苄西林敏感,对红霉素、四环素中敏,对阿米卡星、头孢吡酮、头孢噻吩、诺氟沙星、克林霉素、苯唑西林、环丙沙星、万古霉素、氯霉素、头孢拉啶、呋喃妥因、黏菌素均耐药,并携带多重耐药基因。     

我国奶牛主要养殖区乳房炎病原菌区系分布及对抗生素敏感性的最新调查研究

旨在查明引起我国奶牛主要养殖区乳房炎的病原菌区系分布及流行株对抗生素的耐药情况,为提高奶牛乳房炎防控提供参考。对326份临床型乳房炎样品进行细菌的分离、鉴定,用药敏纸片法对检出率较高的5种病原菌进行抗生素敏感性检测。结果共分离出54种263株菌,奶样中细菌总检出率为84.36%,与奶牛乳房炎密切相关的病原菌19种共214株,病原菌检出率为81.37%。检出率较高的前5种病原菌分别是大肠杆菌(29.28%)、金黄色葡萄球菌(8.75%)、产色葡萄球菌(6.84%)、沙雷氏菌(4.56%)和屎肠球菌(2.66%)。药敏实验结果显示,大肠杆菌对氯霉素、氨苄西林和阿莫西林克拉维酸等耐药严重,耐药率为60%~100%;金黄色葡萄球菌对青霉素G、红霉素和环丙沙星的耐药率均为100%;沙雷氏菌和屎肠球菌的耐药谱基本一致;产色葡萄球菌对庆大霉素、红霉素、四环素和克林霉素等高度敏感,敏感率为67%~100%。说明乳房炎主要病原菌对临床上常用的抗生素均产生了不同程度的耐药性,临床给药时应交叉用药,并定期进行药物敏感性检测,减少耐药菌株的产生。     

2株猪源性绿色气球菌的分离鉴定及药敏特性研究

对2份病死猪病料,进行了猪圆环病毒qPCR检测和细菌学分离鉴定,同时对分离株细菌的耐药性和16S rRNA基因的同源性进行了分析。结果显示:2份猪病料猪圆环病毒核酸均为阳性;从2份病料中各分离出1株α溶血性的细菌,经生理生化和分子生物学方法综合鉴定为绿色气球菌;其2株分离株细菌的16S rRNA基因序列与GenBank上已登录(AccessionNo:NR104708、NR118723)的绿色气球菌的相应序列具有高度同源性≥99.0%,同JN713500、HQ646184、AY707781、EU075039的遗传关系最为亲密;2株分离株细菌对诺氟沙星、克林霉素、麦迪霉素、呋喃唑酮、多西环素、四环素、红霉素耐药;对丁胺卡那霉素、氧氟沙星、头孢他啶中度敏感;对头孢唑啉、羧苄西林、头孢氨苄、头孢哌酮、头孢拉定、多粘菌素B、万古霉素高度敏感;对青霉素、新霉素、卡那霉素、氯霉素、庆大霉素、环丙沙星的药敏性各不相同。     

云南地区副鸡嗜血杆菌的分离及药敏试验

从云南12个县(市、区)17个养鸡场疑似发生鸡传染性鼻炎的病(死)鸡鼻腔中采集病料,通过细菌分离培养、生长特性及琼脂凝胶沉淀试验,证实分离到副鸡嗜血杆菌34株,其中20株具有血凝活性,血凝价在3log2~9log2,另14株无血凝活性。药敏试验结果表明:分离株对头孢氨苄、妥布霉素、卡那霉素、庆大霉素、丁胺卡那、环丙沙星、恩诺沙星、氯霉素、利福平、痢特灵高度敏感,对青霉素、氨苄青霉素、阿莫西林、链霉素、红霉素、罗红霉素、强力霉素、四环素耐药。     

Antimicrobial susceptibility of Staphylococcus aureus and Staphylococcus pseudintermedius isolated from various animals

This study characterized the antimicrobial susceptibility of 221 Staphylococcus aureus isolated from various species, and 60 canine Staphylococcus pseudintermedius isolated from 1986 through 2000 at the Western College of Veterinary Medicine (WCVM). Resistance of S. aureus was most common to penicillin (31%) and tetracycline (14%); resistance of S. pseudintermedius to penicillin was present in 8% and to tetracycline in 34% of isolates. Resistance to trimethoprim/sulfamethoxazole was only seen among S. pseudintermedius, and there was no resistance to amoxicillin/clavulanate, ampicillin/sulbactam, cephalothin, amikacin, gentamicin, enrofloxacin, chloramphenicol, or rifampin among any isolate. Inducible clindamycin resistance was found in both S. aureus and S. pseudintermedius, highlighting the need for careful interpretation of culture and susceptibility test results. There were significant differences in the minimum inhibitory concentrations of penicillin, ciprofloxacin, enrofloxacin, clindamycin, erythromycin, chloramphenicol, and tetracycline between avian, bovine, equine, and porcine isolates.     

The susceptibility of isolates of Corynebacterium equi to antimicrobial drugs

Fifty-one isolates of Corynebacterium equi recovered from pigs and horses belonging to two capsular serotypes were tested for susceptibility to antimicrobial agents. No clear differences were detected in sensitivity between isolates of different sources or serotypes. All isolates were sensitive to <0.25 μg/ml of erythromycin and gentamicin. The following minimum inhibitory concentrations (MICs) of antimicrobial agents were determined for ≤90% of isolates: methicillin >16 μg/ml, clindamycin 1–2 μg/ml, tobramycin ≤1 μg/ml, cephalothin 8–64 μg/ml, kanamycin 2–8 μg/ml, amikacin ≤1–2 μg/ml, penicillin 2–≤4 μg/ml, ampicillin 2–8 μg/ml, trimethoprim-sulfa 4/76–32/608 μg/ml tetracycline 1–4 μg/ml and chloramphenicol 8–16 μg/ml.     

Heterogeneity of methicillin-sensitive Staphylococcus pseudintermedius strains isolated from diseased dogs

Thirty nine canine S. pseudintermedius strains were examined for antibiotic susceptibility and genetic polymorphisms. All strains were methicillin-sensitive S. pseudintermedius (MSSP). Resistance to penicillin was most prevalent (66.6%), followed by resistance to neomycin (56.4%), erythromycin (53.8%), clindamycin (48.7%), chloramphenicol (48.7%), and tetracycline (46.2%). Pulsed-field electrophoresis (PFGE) showed a high genetic polymorphism in the investigated strains.     

Obligate anaerobes in clinical veterinary medicine: susceptibility to antimicrobial agents

Ninety-nine isolates of obligate anaerobic bacteria obtained from clinical material were tested for susceptibility to ten antimicrobial agents. Regardless of the species of animal from which the isolates were obtained 90–95% were inhibited by ≤4 μg of ampicillin/ml, ≤4 μg of chloramphenicol/ml, ≤1 μg clindamycin/ml, ≤2 μg metronidazole/ml, ≤8 μg minocycline/ml, ≤16 μg penicillin Gyml, and ≤16 μg tetracycline/ml. All the aminoglycoside antibiotics tested (gentamicin, kanamycin, neomycin, and streptomycin) were shown to be relatively ineffective requiring ≥128 μg/ml for the inhibition of >50%of the isolates. The minimal inhibitory concentration of penicillin G and tetracycline tended to be higher for isolates from non-human primates (penicillin G) and ruminants (tetracycline).     

The antibiotic sensitivity patterns of Bacillus anthracis isolated from the Kruger National Park

Forty-four isolates of Bacillus anthracis made from carcasses and soil in different localities of an endemic anthrax area in the Kruger National Park, South Africa, were tested by standard disc diffusion for their susceptibility to 18 different antibiotics. These were ampicillin, penicillin G, sulphatriad, streptomycin, clindamycin, gentamicin, fusidic acid, trimethoprim, sulphamethoxazole, chloramphenicol, erythromycin, methicillin, tetracycline (2 different concentrations), novobiocin, cefotaxime, netilmicin, cefamandole and cefoxitin. All the isolates were susceptible to ampicillin, streptomycin, chloramphenicol, erythromycin, tetracycline, methicillin and netilmicin. More than 90% of the isolates were sensitive to clindamycin, gentamicin and cefoxitin, whereas only 84.1% of the isolates were sensitive to penicillin G, 86.4% to novobiocin and 68.18% to cefamandole. Complete resistance in 100% of the isolates was encountered with trimethoprim and sulphamethoxazole, with 95.45% for sulphatriad. Moderate sensitivity occurred with penicillin G (15.9% of the isolates), clindamycin (6.8%), novobiocin (13.6%), fusidic acid (84.1%), cefotaxime (100%), cefamandole (31.8%) and cefoxitin (6.8%). The relevance of the findings to the therapeutic uses of different types of antibiotic in human clinical cases referred to in the literature is discussed.     

Prevalence of and resistance to anti-microbial drugs in selected microbial species isolated from bulk milk samples

The prevalence of strains of Staphylococcus aureus, coagulase-negative (CN) staphylococci, Listeria monocytogenes, Escherichia coli, Enterococcus faecalis, E. faecium and Bacillus cereus, was investigated in 111 bulk milk samples. Staphylococcus aureus was isolated from 38 samples, CN staphylococci from 63 samples, E. coli from 49 samples, E. faecalis or E. faecium from 107 samples, and L. monocytogenes from two samples. Bacillus cereus was not found in any of the samples and three samples were free of any of the selected species. Sensitivity to the anti-microbial drugs amikacin, ampicillin, ampicillin + sulbactam, cephalothin (CLT), cephotaxime, clindamycin, chloramphenicol (CMP), co-trimoxazole, erythromycin (ERY), gentamicin, neomycin, norfloxacin, oxacillin, penicillin, streptomycin (STR), tetracycline (TTC) and vancomycin was tested using the standard dilution technique. Minimum inhibitory concentration (MIC) characteristics (MIC50, MIC90, MIC range) were determined for each microbial species. Resistance against one or more anti-microbial drugs was found in 93% of S. aureus, 40% of CN staphylococci, 73% of E. coli, 88% of E.faecalis, 55% of E.faecium, and one L. monocytogenes strain. Most of the strains, particularly enterococci, were resistant to STR, TTC, and ERY (MIC50 4 microg/ml). A high percentage of staphylococci were resistant to beta-lactam antibiotics. High resistance to CLT was found in 11 strains of E. coli (MIC 256 microg/ml) and strains resistant to CMP (MIC90 16 microg/ml) were detected. The highest numbers of resistance phenotypes were found in E. coil (16) and CN staphylococci (12). Eighteen identical resistance phenotypes were demonstrated in indicator bacteria (E. coli, E. faecalis, E. faecium) and pathogens (S. aureus, CN staphylococci) isolated from the same bulk milk sample. The obtained resistance data were matched against the herd owners' information on therapeutic use of the drugs. This confrontation could not explain the findings of strains resistant to ERY or CMP. Our findings are evidence of selection of resistant strains among not only pathogenic agents, but also among indicator bacteria which can become significant carriers of transmissible resistance genes.     

Antimicrobial susceptibility patterns of the A and T types of Pasteurella haemolytica

Minimal concentrations of penicillin, ampicillin, cephalothin, chloramphenicol, tetracycline, erythromycin, nitrofurantoin, kanamycin and gentamicin inhibitory to Pasteurella haemolytica biotypes A and T were determined. They were found to be significantly higher for T than for A type strains in the case of all the antimicrobial drugs tested except the two aminoglycosides kanamycin and gentamicin, for which no differences were observed. In the case of penicillin the differences were so marked that they may be useful as a basis for biotyping P haemolytica isolates. The emergence of antibiotic-resistant strains observed in recent years, however, may limit such application.     

上海地区奶牛的乳房炎金黄色葡萄球菌耐药性

为调查上海地区奶牛乳房炎金黄色葡萄球菌的耐药性,采集上海地区乳房炎患病乳样60 份,进行金黄色葡萄球菌的分离鉴定及药敏实验。结果表明：经分离鉴定,共检出8 株金黄色葡萄球菌,分离率为13.33%;药敏实验结果表明,分离得到的金黄色葡萄球菌对青霉素G和氨苄西林的耐药率最高,均为100.00%,对磺胺甲恶唑的耐药率次之,为50.00%,对头孢克洛、头孢唑肟、洛美沙星、诺氟沙星、四环素、庆大霉素、红霉素、克林霉素和氯霉素的耐药率均为37.50%,对环丙沙星和氧氟沙星的耐药率均为25.00%,对头孢噻肟、头孢他啶     

The effects of combinations of selected antibiotics on the growth of Corynebacterium equi

The minimal inhibitory concentrations of penicillin G, ampicillin, gentamicin, erythromycin and rifampicin were determined for nine strains of Corynebacterium equi. The effect of combinations of any two of these antibiotics on the killing of these strains was determined at antibiotic concentrations achievable in horses using recommended drug dosages (ampicillin 4.0 μg/ml, gentamicin 1.0 μg/ml and erythromycin 0.25 μg/ml). Penicillin G was used at 4.0 μg/ml and rifampicin at 0.063 μg/ml. The combinations of gentamicin with erythromycin or rifampicin gave antagonistic effects on killing compared to either drug alone. Combinations of erythromycin with rifampicin or penicillin showed synergistic effects, as did penicillin-gentamicin. All other combinations, and a triple combination of penicillin-rifampicin-erythromycin, showed additive effects only.     

Prevalence and antimicrobial resistance of Campylobacter in raw milk in the selected areas of Poland

During the recent years, an immense increase in the number of food poisoning cases in people caused by Campylobacter (C.) species has occurred. Raw milk, next to poultry meat, is considered the most frequent cause of food poisoning in people caused by the subject bacteria, although it is not always possible to isolate Campylobacter cells from the incriminated milk. Most probably this difficulty is caused by low concentration of the pathogen in milk at the level of 2/3 cells/ml although even such low concentration represents risk to human health. The present study was aimed at determining the occurence of Campylobacter bacteria in milk originating from selected regions of Poland. The isolation method applied in this work was effective in recovering as few as 0.1 cell of Campylobacter per g of food. Among 150 bulk milk samples tested, Campylobacter spp. was isolated from 7 (4.6%) ones. The biochemical identification of the isolated strains conducted by means of conventional biochemical tests as well as by applying the API - Campy tests revealed that all the isolates belonged to the C. jejuni species. Determination of resistance to antibiotics was performed by means of the diffusion disks method for the following antibiotics: gentamicin, ciprofloxacin, ampicillin, chloramphenicol, erythromycin, doxycyclin and tetracycline. Among 7 isolates tested, all were susceptible to ampicillin, chloramphenicol, erythromycin and gentamicin, 28.5% to doxycyclin and 14.2% to tetracycline and ciprofloxacin.