Antimicrobial Susceptibility of Escherichia coli Isolated from Iranian Broiler Chicken Flocks, 2005–2006

Escherichia coli is a major pathogen of worldwide importance in commercially produced poultry, contributing significantly to economic losses in chickens and turkeys. One hundred thirty-five cases in broilers were examined and cultured for isolation and antimicrobial sensitivity evaluation of E. coli between January 2005 and December 2006. In 103 cases (76.3%) E. coli were isolated and in 32 cases (23.7%) no E. coli growth was observed. Multiple resistances were seen in all isolates. All isolates were uniformly resistant to Tiamuline, Tylosin, and Bacitracin. We observed low levels of resistance to Gentamicin (12%), Kanamycin (0%), and Florfenicol (39%). Percentages of resistance to Tiamuline, Bacitracin, Tylosin, Colistin, and Erythromycin (≥99%); Tetracycline (96%); Oxytetracycline (93%); Flomequine (87%); Neomycine (87%); Lincospectin (79%); Difloxacin (78%); Enrofloxacin (76%); Cotrimoxazole (72%); Chloramphenicol (52%); and Ampicillin (49%) were determined. Our data show high levels of multiresistance among Iranian E. coli isolates. It seems that the pattern of antibiotic resistance of bacteria that are clinically important for the poultry industry should be monitored.     

浙江部分地区屠宰场待宰猪链球菌的检测及药敏试验

对浙江部分地区屠宰场中猪链球菌的分布和耐药情况进行调查.结果表明,猪链球菌的携带率为13.1%(38/290),其中2型猪链球菌为0.69%(2/290);不同地区之间待宰猪的猪链球菌携带率存在明显的差异,义乌地区的猪链球菌携带率为21.0%(22/139),而江山为0;各地区不同分离株的耐药性无明显差异,均对β-内酰胺类药物敏感,50%以上分离株对四环素、强力霉素、红霉素、麦迪霉素等几种药物表现为多重耐药.     

Antimicrobial resistance of Escherichia coli isolates from canine urinary tract infections

This study determined the antimicrobial resistance profiles of Escherichia coli isolates from dogs with a presumptive diagnosis of urinary tract infection (UTI). Urine samples from 201 dogs with UTI diagnosed through clinical examination and urinalysis were processed for isolation of Escherichia coli. Colonies from pure cultures were identified by biochemical reactions (n=114) and were tested for susceptibility to 18 antimicrobials. The two most frequent antimicrobials showing resistance in Urinary E. coli isolates were oxytetracycline and ampicillin. Among the resistant isolates, 17 resistance patterns were observed, with 12 patterns involving multidrug resistance (MDR). Of the 69 tetracycline-resistant E. coli isolates, tet(B) was the predominant resistance determinant and was detected in 50.9% of the isolates, whereas the remaining 25.5% isolates carried the tet(A) determinant. Most ampicillin and/or amoxicillin-resistant E. coli isolates carried bla_TEM-1 genes. Class 1 integrons were prevalent (28.9%) and contained previously described gene cassettes that are implicated primarily in resistance to aminoglycosides and trimethoprim (dfrA1, dfrA17-aadA5). Of the 44 quinolone-resistant E. coli isolates, 38 were resistant to nalidixic acid, and 6 were resistant to nalidixic acid, ciprofloxacin and enrofloxacin. Chromosomal point mutations were found in the GyrA (Ser83Leu) and ParC (Ser80Ile) genes. Furthermore, the aminoglycoside resistance gene aacC2, the chloramphenicol resistant gene cmlA and the florfenicol resistant gene floR were also identified. This study revealed an alarming rate of antimicrobial resistance among E. coli isolates from dogs with UTIs.     

宠物源大肠埃希菌的分离鉴定和耐药性研究

为调查长春地区宠物源大肠埃希菌耐药流行情况,从2家宠物医院采集135份宠物肛拭子样品,分离和鉴定大肠埃希菌并进行多重PCR分群。测定大肠埃希菌分离株对19种抗菌药物的耐药性,并鉴定超广谱β-内酰胺酶(ESBLs)表型。共分离鉴定获得95株宠物源大肠埃希菌,它们对氨苄西林和哌拉西林的耐药率最高(78.9%和76.8%);其次是四环素(61.6%);对头孢唑林、头孢噻肟、头孢吡肟、庆大霉素、复方新诺明、环丙沙星和左氧氟沙星的耐药率均超过了50%;所有分离株均对亚胺培南和美罗培南敏感。其中15个分离株对受试的抗菌药物全部敏感(15.8%),63株呈多重耐药表型(66.3%)。ESBLs型菌株占53.7%。本研究探明了长春地区宠物源大肠埃希菌的耐药流行情况,对宠物临床上用药具有指导价值。     

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。     

Antimicrobial Susceptibility Patterns in Urinary Tract Infections in Dogs (2010–2013)

Background

Urinary tract infections (UTIs) are common in dogs. The responsible bacterial populations have evolved with increasing resistance to many antimicrobials.

Objective

To characterize the antimicrobial susceptibility patterns of canine urinary tract isolates over a 51‐month period.

Animals

One thousand six hundred and thirty‐six bacterial isolates from 1,028 dogs.

Methods

Aerobic bacterial isolate growth and susceptibility data from urine cultures of dogs were identified, retrospectively. Medical records were reviewed to obtain signalment, comorbidities, and antimicrobial use in the previous 30 days. The UTIs were further categorized as uncomplicated, complicated, or pyelonephritis.

Results

Common bacterial isolates identified were Escherichia coli (52.5%), Staphylococcus spp. (13.6%), and Enterococcus spp. (13.3%). In vitro susceptibility among all isolates varied for commonly prescribed antimicrobials (amoxicillin [59%], amoxicillin/clavulanic acid [76%], cephalexin [66%], enrofloxacin [74%] and trimethoprim‐sulfamethoxazole [86%]). For all antimicrobials tested (except aminoglycosides), in vitro susceptibility was higher in uncomplicated versus complicated infections (P < .05). Uncomplicated infection isolate susceptibility rates remained ≤90% for PO administered antimicrobials. Administration of amoxicillin, doxycycline, and enrofloxacin, but not amoxicillin/clavulanic acid in the previous 30 days was associated with resistance to that antimicrobial. Multidrug resistant isolates of E. coli and Staphylococcus spp. were more common in dogs with complicated than uncomplicated UTIs (36% versus 21%, P < .0001).

Conclusions and Clinical Importance

In vitro susceptibility was highly variable and no PO administered antimicrobial had >90% efficacy among isolates tested. Multidrug resistance was frequent among isolates tested suggesting that routine culture and susceptibility testing is indicated. Previously prescribed antimicrobials may affect empirical choices made pending susceptibility testing.     

Correlation of minimum inhibitory concentrations between human and animal antimicrobials against Escherichia coli isolated from livestock

We analyzed the correlation between minimum inhibitory concentrations (MICs) of antimicrobials used in humans and those used in animals to enable comparison of antimicrobial susceptibility between Escherichia coli isolated from humans and those from animals. We compared the following pairs of MIC data: piperacillin (PIPC) to ampicillin (ABPC), amikacin (AMK) to kanamycin (KM), minocycline (MINO) to oxytetracycline (OTC), and levofloxacin (LVFX) to enrofloxacin (ERFX) using 103 isolates of E. coli from healthy livestock (cattle, pigs, broiler chickens, and layer chickens). Kappa analysis of the agreement for resistance and susceptibility between PIPC and ABPC, AMK and KM, MINO and OTC, and LVFX and ERFX showed almost perfect (κ = 0.81), slight (κ = 0.12), fair (κ = 0.37), and moderate (κ = 0.46) agreement, respectively. Within the antimicrobial pairs, all isolates resistant to the human antimicrobial were also resistant to the veterinary antimicrobial. However, there was less agreement within the pairs for those isolates that were sensitive to the human antimicrobial. The percentage agreement for susceptibility, defined as the percentage of isolates sensitive to both antimicrobials compared with isolates sensitive to both antimicrobials, as well as those sensitive only to the human antimicrobial, was 89.9%, 87.3%, 64.0%, and 89.9% for PIPC and ABPC, AMK and KM, MINO and OTC, and LVFX and ERFX, respectively. Our results suggest that the possibility of missing the resistance for antimicrobials used in human medicine by examining MICs for the equivalent antimicrobials used in veterinary medicine is low.     

Analysis of Ribosome Genotyping and Antimicrobial Resistance in Enterococcus faecalis Isolated from Pigs and Chickens

This study was to investigate the ribosome genotyping and antimicrobial resistance in Enterococcus faecalis strains isolated from 2 large-scale farms in Shanghai.40 isolates were evaluated for their sensitivity to 12 antimicrobial agents by broth microdilution,and the ribosome genotyping (ribotype) was characterized by the Riboprinter^® Microbial Characterization System.The resistance rates of most antimicrobial drug were relatively high and multidrug resistant strains were detected with more than 80%.4 strains of Enterococcus faecalis isolated from pigs were resistant to vancomycin,including 2 strains of vancomycin highly resistant (MIC>64 mg/L) with the same time highly resistant to gentamicin and streptomycin (MIC>2 048 mg/L).The results showed that multidrug resistance of Enterococcus faecalis was a serious issue,and the resistant phenotypes of the same type of ribotype was not entirely consistent.     

猪、鸡源分离粪肠球菌的核糖体分型及耐药性分析

对上海地区1个规模化养猪场和1个规模化养鸡场分离鉴定的40株粪肠球菌,采用微量肉汤稀释法对12种抗菌药物进行药敏试验,采用Riboprinter^®微生物基因指纹鉴定系统检测分离菌株的基因指纹图谱,分别检测分离菌株中的核糖体型和耐药性。结果表明,在40株粪肠球菌中,80%以上为多重耐药菌株,有4株猪源粪肠球菌对万古霉素耐药,其中有2株表现为对万古霉素高度耐药（MIC>64 mg/L）,且对链霉素和庆大霉素同时表现为高度耐药（MIC>2 048 mg/L）。从耐药表型和核糖体分型共同分析粪肠球菌的耐药性,发现多重耐药性严重,同一核糖体型菌株的耐药表型并非完全一致。     

65株不同圈养野生动物源性肠杆科菌的药敏分析

采用K-B法药敏试验,分析圈养野生动物肠杆科菌对青霉素类、头孢类、氨基糖甙类、喹诺酮类、磺胺类的10种临床常用抗生素的药敏情况。结果显示：最敏感的是头孢稀类的三代头孢,头孢哌酮和头孢噻肟,其敏感率均为83.1%;较敏感的为喹诺酮类和氨基糖甙类药物,敏感率大于或等于60%;敏感性较差的是一代头孢中的头孢拉定、磺胺类药中的复方新诺明、青霉素类的氨苄青霉素,其敏感性分别为58.5%、43.1%和21.5%,被研究结果为兽医临床用药提供了依据。     

Classification and Antimicrobial Susceptibilities of Enterococcus Species Isolated from Apparently Healthy Food‐Producing Animals in Japan

Summary A total of 1024 enterococci were recovered from faeces of healthy animals from 178 cattle, 178 pig and 156 broiler farms. Enterococcus faecium was the predominant species recovered (35.8%), followed by E. faecalis (31.3%) and E. hirae (25.6%). Oxytetracycline resistance was most frequently found among E. faecalis (85.9%), E. faecium (58.8%) and E. hirae (48.1%). Resistance rates to almost all antimicrobials were higher in E. faecalis than E. faecium and E. hirae. Isolates from cattle were more susceptible to the antimicrobials studied than those from pigs and broilers. VanA‐ or VanB‐type vancomycin‐resistant enterococci have not been found since the ban of avoparcin use 5 years ago.     

猪链球菌2型的分离鉴定与药敏试验

从广东省某猪场病猪脑内分离到1株细菌,经培养特性观察、镜检、生化鉴定和PCR检测,结果鉴定为链球菌2型。该菌对阿莫西林、头孢拉定、头孢喹肟、头孢曲松均敏感;对青霉素G、氨苄西林、恩诺沙星、氧氟沙星、阿奇霉素、多西霉素中度敏感;对林可霉素、壮观霉素、链霉素、土霉素、复方新诺明、阿米卡星耐药。     

北京市伴侣动物源肠球菌的抗菌药物耐受情况调查

为研究北京市伴侣动物源肠球菌对常见抗菌药物的耐受情况,于2015年5月至2016年1月以北京市某宠物医院门诊就诊犬、猫作为采样对象,采集犬、猫自然排出的粪便作为样品,共得到样本320份。采用选择性培养基进行菌株分离和VITEK-2型全自动微生物分析仪进行肠球菌的鉴定;对分离鉴定的菌株进行8类11种常见抗菌药物敏感性试验;同时进行高水平庆大霉素和高水平链霉素耐受的检测试验,对受试肠球菌的耐药性和多重耐药性进行分析。共得到菌落形态及生化特性不同的非重复的肠球菌318株,其中粪肠球菌（49.06%）和屎肠球菌（29.87%）分离率较高。受试肠球菌对高水平庆大霉素和高水平链霉素的耐药率分别为39.94%和43.40%,对四环素（78.62%）、红霉素（67.30%）和奎诺普丁-达福普汀耐药率（43.71%）较高,对替加环素全部敏感,对万古霉素和呋喃妥因非耐药率也很高（均为98.74%）。受试肠球菌对1类到7类抗菌药物有不同程度的耐药性,多重耐药现象普遍,多重耐药率高达57.23%。耐受4类抗菌药物的数量最多（n=65株）。经分析共得到44种不同的耐药谱,以耐受4类药物的红霉素-奎诺普丁-达福普汀-四环素-高水平氨基糖苷类耐药谱占比最高（45/318,14.15%）。本研究证实受试的北京市伴侣动物源肠球菌对常见抗菌药物的耐药程度较高,多重耐药情况普遍存在,应加强对其耐药性的监测工作。     

Research on Antimicrobial Resistance Characteristics of Enterococcus spp. from Companion Animals in Beijing

In order to study the tolerance of Enterococcus spp.from companion animals to common antibiotics in Beijing,320 samples were collected from dogs and cats in a pet hospital in Beijing from May 2015 to January 2016.The strains were isolated by selective culture medium and identified by VITEK-2 Compact 60.The sensitivity test of 11 kinds of common antibiotics in 8 categories was carried out for the isolated and identified strains.At the same time,the high-level gentamicin and high-level streptomycin resistance test were carried out to analyze the drug resistance and multiple drug resistance of Enterococcus.A total of 318 strains of non repetitive enterococci with different colony morphology and biochemical characteristics were obtained.The isolation rates of Enterococcus faecalis (49.06%) and Enterococcus faecium (29.87%) were higher.The resistance rates of Enterococcus to high-level gentamicin and high-level streptomycin were 39.94% and 43.40%,respectively.The resistance rates to tetracycline (78.62%),erythromycin (67.30%) and quinoproptin dapfoptin (43.71%) were very high.All of them were sensitive to tigecycline,and the non-resistant rate to vancomycin and nitrofurantoin was also high (98.74%).Enterococcus tested showed different degrees of resistance to class 1 to class 7 antibiotics,and the multidrug resistance was common,and the multidrug resistance rate was as high as 57.23%.The number of resistant antibiotics was the highest (n=65).A total of 44 different drug resistance profiles were obtained.Among them,erythromycin-quinoptin-daptoptin-tetracycline-high level aminoglycoside resistant spectrum accounted for the highest proportion (45/318,14.15%).This study confirmed that Enterococcus spp.isolated from companion animals in Beijing was highly resistant to common antibiotics,and multidrug resistance was prevalent.Therefore,it was necessary to strengthen the monitoring of drug resistance.     

奶牛临床型乳房炎的细菌分离鉴定与耐药性分析

2011年山西省多个奶牛场发生了较严重的乳房炎,对76份采集的奶样进行细菌分离鉴定并采用药敏纸片法检测主要分离菌的抗生素耐药情况。所分离细菌以革兰氏阳性菌为主,革兰氏阳性球菌和其他革兰氏阳性菌分别占60.67%和23.59%。分离出多种病原菌和机会致病菌,主要的病原菌有链球菌、金黄色葡萄球菌、大肠杆菌等,检出率为2.24%~11.24%,其中无乳链球菌的检出率最高;机会致病菌有粪链球菌、微球菌、克雷伯菌、凝固酶阴性葡萄球菌等,检出率为1.12%~11.24%,其中粪链球菌和微球菌的检出率较大,分别为11.24%和6.74%。药敏试验检测结果显示,在所选的15种药物中,主要分离菌均对丁胺卡那霉素、氟哌酸和恩诺沙星3种药物敏感;大肠杆菌、克雷伯菌、凝固酶阴性葡萄球菌对青霉素类和β-内酰胺/β-内酰胺酶抑制剂类药物产生了极强的耐药性,耐药率均为100%;乳房链球菌对该类药物也产生不同程度的耐药,耐药率为20%~100%;对链霉素产生100%耐药的细菌有大肠杆菌、克雷伯菌、无乳链球菌、乳房链球菌、停乳链球菌等细菌;部分分离菌对卡那霉素、庆大霉素、链霉素、四环素、红霉素、先锋霉素Ⅴ、复方新诺明等药物产生不同程度耐药。被检奶牛场混合感染较为严重,应进一步加强环境卫生管理,临床治疗应合理有效用药。     

猪源粪肠球菌的基因型及耐药性分析

为了解上海地区规模化猪场中粪肠球菌的耐药性和基因型,2013年3月-2014年5月从上海地区10个规模化养猪场收集到分离鉴定的粪肠球菌133株,采用微量肉汤稀释法对12种抗菌药物进行药敏试验,采用PCR技术分别检测分离株中β-内酰胺类抗生素耐药相关基因(TEM)、氨基糖苷类抗生素耐药相关基因[aac(6’)/aph(2")和aph(3’)-Ⅲ和ant(6)-Ⅰ]、四环素耐药相关基因(tetM)、红霉素耐药相关基因(ermB和mefA)和万古霉素耐药相关基因(vanA和vanB)。结果显示,在133株粪肠球菌中,耐药基因ermB、tetM、TEM、ant(6)-Ⅰ、aac(6’)/aph2"、aph(3’)-Ⅲ、vanA的检出率分别为:95.5%(127/133)、91.0%(121/133)、63.2%(84/133)、45.9%(61/133)、42.1%(56/133)、24.1%(32/133)、3.0%(4/133);未检出mefA和vanB基因的菌株。分离菌株对12种抗菌药物的耐药性较为严重,且以6~9耐为主要耐药株,占81.2%。试验表明,上海地区猪源粪肠球菌多重耐药现象严重,携带抗菌药物相关耐药基因是导致分离株耐药的主要原因。