Characterization of antimicrobial resistance patterns and class 1 integrons in Escherichia coli O26 isolated from humans and animals

Antimicrobial resistance patterns and the prevalence of antimicrobial resistance genes and class 1 integrons in 35 Escherichia coli O26 isolated from humans and food-producing animals were evaluated. All isolates were resistant to cefaclor, cefalothin and sulfonamide and were susceptible to amikacin, gentamicin, cefmetazole, cefotaxime, ceftriaxone, ciprofloxacin, norfloxacin and trimethoprim. Most isolates were resistant to aztreonam, ampicillin, tetracycline, streptomycin and kanamycin. All ampicillin- and streptomycin-resistant E. coli O26 carried ampC and strA-strB gene sequences, respectively. Florfenicol- and chloramphenicol-resistant isolates carried floR but not cmlA. Class1 integrons were identified in 14% of E. coli O26 isolates. To our knowledge, this is the first report describing the presence of multiple antimicrobial resistance genes in E. coli O26 isolated from human and animal origins.     

In vitro susceptibility to 15 antibiotics of vibrios isolated from penaeid shrimps in Northwestern Mexico

The sensitivity of 144 isolates of Vibrio spp isolated from shrimp was compared using common antibiotics and those used in the shrimp industry. The in vitro susceptibility of the isolates was studied using amikacin, ampicillin, carbenicillin, cephalothin, cefotaxime, ceftriaxone, chloramphenicol, gentamicin, netilmicin, nitrofurantoin, pefloxacin, trimethoprim-sulphamethoxazole, enrofloxacin, oxytetracycline and florfenicol. The relationship between the minimum inhibitory concentration and the disk inhibition zone was also studied for some antibiotics.     

Antibiotic resistance in Salmonella enterica subsp. enterica strains isolated in Poland from 1998 to 1999.

A total of 326 Salmonella enterica subsp. enterica strains representing 29 serotypes, isolated from human stool specimens during 1998-1999 in sanitary-epidemiological units in Poland were tested for antibiotic susceptibility by a standard disk diffusion method. The antibiotics used were ampicillin, cefotaxime, chloramphenicol, tetracycline, streptomycin, gentamicin, kanamycin, nalidixic acid, ciprofloxacin, furazolidone, cotrimoxazole, sulphonamides and trimethoprim. In addition, 201 strains belonging to the five most commonly isolated serotypes (S. Enteritidis, S. Typhimurium, S. Hadar, S. Infantis and S. Virchow) also had minimal inhibitory concentrations (MICs) determined for amoxycillin/clavulanic acid. Selected strains were screened for production of extended spectrum beta-lactamases (ESBLs). There were 49.4% of Salmonella enterica subsp. enterica strains resistant to two or more antibiotics, with the highest prevalence of multiple resistant strains among serotypes Typhimurium, Hadar and Virchow. Resistance to ampicillin, streptomycin, tetracycline, nalidixic acid, furazolidone and sulphonamides occurred most frequently. Over 93% of S. Virchow strains were resistant to furazolidone. No strains resistant to ciprofloxacin by disk-diffusion method were detected but 31.3% of isolates of the 201 strains representing the five most common serotypes had reduced ciprofloxacin susceptibility (MICs ranging 0.125-0.5 mg/l). One strain (S. Mbandaka) was resistant to cefotaxime and produced ESBL.     

Antimicrobial susceptibility of Haemophilus influenzae, Haemophilus parainfluenzae and Moraxella catarrhalis isolated from adult patients with respiratory tract infections in four southern European countries. The ARISE project

Over a 7-month period in 2000-2001, 1213 Haemophilus influenzae, 112 Haemophilus parainfluenzae and 142 Moraxella catarrhalis isolates were recovered from adult patients with respiratory tract infections. Patients were from four southern European countries (Spain, Italy, Portugal and Greece). The antimicrobial susceptibility of the isolates to 11 antibiotics was determined in a central laboratory. The most active drugs on the basis of MICs were levofloxacin, cefditoren, cefotaxime, cefpodoxime and amoxicillin/clavulanate. MICs > or = 2 mg/l for amoxicillin were found in 19.5, 28.6, and 75.4% of H. influenzae, H. parainfluenzae and M. catarrhalis isolates, respectively. Isolates of H. influenzae and H. parainfluenzae with reduced susceptibility or that were fully resistant to amoxicillin/clavulanate, cefuroxime and clarithromycin were detected (0.2-1.8%) as well as M. catarrhalis resistant to clarithromycin (0.7%). Regular surveys of resistance patterns for antimicrobial agents are necessary.     

Antibiotic resistance in a very remote Amazonas community

In a very remote human community of the Peruvian Amazonas with minimal antibiotic exposure, high levels of acquired resistance to the oldest antibiotics (ampicillin, tetracycline, trimethoprim/sulfamethoxazole, streptomycin and chloramphenicol) were detected in commensal Escherichia coli, with remarkable diversity of resistant clones and of resistance genes and plasmids. This pattern was similar overall to that previously observed in a very remote community of Bolivia. It was also similar to that observed in the nearest urban area, except for a lower dominance of resistant isolates and the absolute lack of quinolone resistance in the remote community. Present findings suggest that antibiotic resistance observed in remote communities with minimal antibiotic exposure is a general phenomenon contributed by complex mechanisms and provide new insights into the mechanisms involved in this phenomenon.     

Beta-lactamase production in Prevotella and in vitro susceptibilities to selected beta-lactam antibiotics [corrected

This study looked for beta-lactamase production in 100 Prevotella isolates. MICs were determined for amoxycillin, ticarcillin, amoxycillin+clavulanate, cephalothin, cefuroxime, cefixime, cefpodoxime and cefotaxime using the reference agar dilution method (standard M11 A4, NCCLS). Beta-lactamase activity was detected in 58 of the 100 isolates, 24 of 46 black-pigmented Provotella and 34 of 54 non-pigmented Prevotella. All beta-lactamase-negative strains were susceptible to all beta-lactam antibiotics with the exception of cefuroxime and cefixime. Overall, resistance rates of Prevotella strains were lower for ticarcillin (8%) and celefotaxime (12%) than for the other cephalosporins. All Prevotella isolates were susceptible to amoxycillin and were all inhibited by 2 mg/l or less amoxycillin [corrected].     

Antibiotic sensitivity of enteric pathogens in Vietnam

The in vitro antimicrobial susceptibilities of 675 common enteropathogenic isolates from faecal specimens of patients with diarrhea (E. coli, Shigella, Salmonella and V. cholerae), and 568 E. coli isolates from faecal flora of healthy persons, which were collected as part of a National antibiotic resistance surveillance in Vietnam, were determined. The agar dilution method was used for the following nine antibiotics: ampicillin, doxycycline, chloramphenicol, gentamicin, nalidixic acid, kanamycin, trimethoprim, trimethoprim in combination with sulfamethoxazole (1/20), and sulfisomidin. Gentamicin was the most active of the antibiotics tested against all bacterial species with MICs in the range 0.125-4 mg/l. All strains were susceptible to nalidixic acid (0.125-8 mg/l) and more than 90% were susceptible to kanamycin. Among E. coli and Shigella isolates from patients the frequencies of resistance to commonly used antibiotics were high: ampicillin 73% and 84%, doxycycline 83% and 94%, chloramphenicol 71% and 91%, sulfisomidin 82% and 92%, respectively. Resistance to trimethoprin, as well as to the combination with sulfamethoxazole was found in 21% and 23%, respectively. The frequencies of multiple resistance (resistance to three or more antibiotics) were also high (77% and 89%, respectively). Less than 10% of Salmonellae and V. cholerae isolates were resistant to ampicillin, sulfisomidin or trimethoprim. Among E. coli from healthy people the frequencies of resistance were lower than in isolates from patients: ampicillin 23%, doxycycline 40%, chloramphenicol 21% and sulfisomidin 34%. However, the same patterns of multiple resistance were found in both groups.     

老年患者下呼吸道铜绿假单胞菌感染临床分布与耐药性分析

目的:分析老年患者下呼吸道铜绿假单胞菌感染临床分布与耐药性。方法:搜集2011年6月至2013年6月我院老年下呼吸道感染住院患者,分离培养出铜绿假单胞菌菌株痰标本156份,用VITEK2-Compact全自动细菌鉴定及药敏分析系统对临床标本中分离的156株铜绿假单胞菌进行鉴定,并采用琼脂扩散法进行体外药敏试验,依据美国临床实验室标准化协会(CLSI)最新折点判读结果。结果:非多重耐药(MDR)铜绿假单胞菌临床分离株对头孢噻肟、磺胺甲噁唑/甲氧苄啶耐药性最高,耐药率达70%以上;对亚胺培南、美罗培南、氨曲南和头孢哌酮/舒巴坦、头孢他啶、哌拉西林/舒巴坦、阿米卡星的耐药率均在20%以内,其中亚胺培南、美罗培南敏感性均达到100%。而MDR菌株对哌拉西林、头孢噻肟、庆大霉素、环丙沙星、妥布霉素、磺胺甲噁唑/甲氧苄啶高度耐药,耐药率达100%,对哌拉西林/他唑巴坦、头孢吡肟、阿米卡星耐药率高达60%以上,对亚胺培南、美罗培南、氨曲南依旧敏感性较好,耐药率均低于20%。结论:亚胺培南、美罗培南对铜绿假单胞菌有较好的敏感性,可作为老年患者重症下呼吸道铜绿假单胞菌感染治疗的首选药物,如MDR铜绿假单胞菌感染,可联合用药。在联合用药的同时应当加强医院的抗生素合理使用,规范临床用药。     

Antimicrobial susceptibility of Escherichia coli from community-acquired urinary tract infections in Europe: the ECO·SENS study revisited

This study determined the antimicrobial susceptibility of Escherichia coli causing community-acquired, acute, uncomplicated, non-recurrent urinary tract infection in unselected women aged 18-65 years and compared the results with those obtained 8 years earlier in the first ECO·SENS study (1999-2000). During 2007-2008, urine samples were taken from 1697 women in Austria, Greece, Portugal, Sweden and the UK. The countries were chosen to represent areas of Europe indicated to have more (Greece and Portugal) or less (UK, Austria and Sweden) problems with resistance. Antimicrobial susceptibility testing of 903 E. coli isolates (150-200 isolates per country) to 14 antimicrobials was performed by disk diffusion using European Committee on Antimicrobial Susceptibility Testing (EUCAST) breakpoints. In E. coli, resistance to mecillinam, cefadroxil (representing oral cephalosporins), nitrofurantoin, fosfomycin trometamol, gentamicin and the third-generation cephalosporins cefotaxime and ceftazidime was <2%, with the following exceptions: gentamicin in Portugal (2.8%); fosfomycin in Greece (2.9%); and cephalosporins in Austria (2.7-4.1%). Resistance levels were higher for amoxicillin/clavulanic acid (2.0-8.9%) and ciprofloxacin (0.5-7.6%) and much higher to ampicillin (21.2-34.0%), sulfamethoxazole (21.2-31.3%), trimethoprim (14.9-19.1%) and trimethoprim/sulfamethoxazole (14.4-18.2%). Resistance to quinolones and trimethoprim increased between the ECO·SENS I (1999-2000) and ECO·SENS II (2007-2008): nalidixic acid 4.3% to 10.2%; ciprofloxacin 1.1% to 3.9%; and trimethoprim 13.3% to 16.7%. In the previous study, no isolates with extended-spectrum β-lactamase were found; however, in the present study 11 isolates were identified as having either CTX-M or AmpC.     

嗜麦芽窄食单胞菌感染125株临床和耐药性分析

目的了解嗜麦芽窄食单胞菌感染的临床特点及对抗生素的耐药性。方法回顾性分析2006～2008年我院分离的嗜麦芽窄食单胞菌的耐药性以及所致感染病例的临床特点。结果125株嗜麦芽窄食单胞菌对多种抗生素耐药率较高,仅对甲氧苄啶/磺胺甲口恶唑、环丙沙星、替卡西林/克拉维酸、多黏菌素E耐药率较低,分别为11%、29%、12%、23%。结论加强环境消毒和控制广谱抗生素应用可有效降低嗜麦芽窄食单胞菌引起的医院感染的发生,甲氧苄啶/磺胺甲口恶唑、环丙沙星、替卡西林/克拉维酸可作为抗感染治疗的一线用药。     

Evaluation of the in vitro activity of ertapenem and nine other comparator agents against 337 anaerobic bacteria

Ertapenem activity in vitro was compared with that of nine reference antibiotics against 337 anaerobes by determining minimal inhibition concentrations (MICs). Amongst 246 Gram-negative anaerobes, 4, 8, 3, 4, 7, 2 and 52 strains showed resistance to ertapenem, amoxicillin/clavulanic acid, ticarcillin/clavulanic acid, piperacillin/tazobactam, cefoxitin, imipenem and clindamycin, respectively, and all strains were inhibited by metronidazole. Ertapenem MIC(50) values were 0.5, 0.25, 0.06 and 相似文献   

院内感染下呼吸道感染病原菌分布及革兰氏阴性菌耐药性分析

目的分析医院内部感染下呼吸道感染病原菌分布以及总体的耐药性情况,为后期临床合理用药提供可行性的参考依据以及指导。方法对我院所发生的1684例下呼吸道感染患者的总体临床资料进行回顾分析,对患者的痰液标本采取分离培养检定以及药物试敏检验,对菌株的分离以及耐药性特点进行临床分析统计处理。结果 1684份痰液共检测分离出病原菌556株（33%）,在病原菌中占据前三位的依次为克雷伯菌、大肠埃希菌以及铜绿假单胞菌。从患者的药敏结果情况来看,耐药率较高的抗菌药物依次为青霉素类的阿莫西林、哌拉西林、替卡西林,头孢类的头孢噻肟、头孢呋辛。结论革兰阴性杆菌俨然成为了呼吸道感染的主要病原菌,而其耐药情况极为严重,所以强化临床合理用药尤为重要。     

Antibiotic susceptibilities of Yersinia enterocolitica recovered from children over a 12-year period

Antibiotic susceptibility testing by the microdilution technique was performed on 184 Yersinia enterocolitica isolates recovered from children with gastroenteritis in the Detroit area during a 12-year period. The majority of isolates were resistant to ampicillin, ticarcillin and cefazolin. The most active agents were cefotaxime, ceftriaxone, cefepime, gentamicin, tobramycin, sulphamethoxazole/trimethoprim, imipenem and ciprofloxacin. Cefotaxime and ceftriaxone were effective in the treatment of bacteraemia in 12 patients.     

In vitro susceptibility of antibiotics against Vibrio spp. and Aeromonas spp. isolated from Penaeus monodon hatcheries and ponds

Susceptibility patterns to 16 different antibiotics were investigated against pathogenic Vibrio spp. and Aeromonas spp. isolated from shrimp culture hatcheries and ponds in India. Thirteen species of Vibrio (N = 90) and two species of Aeromonas (N = 7) isolates were tested by agar disk diffusion. The results show that 100% of the isolates were resistant to ampicillin, and that 43.2% and 47.4% were sensitive to chlortetracycline and erythromycin, respectively. Susceptibility patterns of another 160 isolates belonging to the genera Vibrio and Aeromonas obtained from the water samples of shrimp hatcheries and ponds were tested against six commonly used antibiotics. Results indicate that isolates from the hatcheries were more resistant to antimicrobials than isolates from the ponds. The minimum inhibitory concentrations of five antibiotics against the different Vibrio spp. and Aeromonas spp. were determined. Ciprofloxacin was found to be the most effective in controlling the isolates from hatcheries and ponds compared with the other antibiotics used in the study. Our results reveal that antibiotic-resistant bacteria are widespread in the shrimp culture hatcheries and ponds in India. Potential risk to human health was not addressed in this study and remains to be elucidated.     

血培养病原菌菌群分布及耐药分析

目的了解南华大学附属第一医院1997年1月～2004年6月年血培养病原菌菌群分布及近2年常见致病菌的耐药情况。方法4686份血标本经BACTEC9050全自动血培养仪培养检测，分离出的致病菌用Sceptor半自动微生物鉴定系统进行鉴定及药敏试验。结果共分离出799株病原菌，血培养阳性率17．1％，检出病原菌分布于20个属，47个种。革兰阳性菌构成比明显高于革兰阴性菌，最常见的血培养菌属是葡萄球菌，占61．7％，其次是沙门菌、肠球菌、链球菌、埃希菌、假单胞菌及不动杆菌。各主要致病革兰阳性菌对万古霉素、呋喃妥因敏感，对环丙沙星较敏感，各主要致病革兰阴性菌对亚胺培南、头孢吡肟及阿米卡星敏感或较敏感。葡萄球菌的耐药情况严重，对青霉素耐药率高达90％以上，凝固酶阴性葡萄球菌(CNS)对多种抗生素耐药情况较金葡菌更严重。肠球菌对多数常用抗生素耐药，对红霉素耐药率高达85．9％。链球菌对青霉素和氨苄西林明显耐药。大肠埃希菌对亚胺培南、头孢替坦、阿米卡星敏感．对头孢吡肟、替卡西林／克拉维酸、阿莫西林／克拉维酸较敏感，对其他多种抗生素耐药。假单胞菌对亚胺培南、环丙沙星、阿米卡星及头孢他啶较敏感，对其他多种抗生素均耐药。不动杆菌对亚胺培南、环丙沙星、头孢吡肟、头孢噻肟、磺胺甲噁唑／甲氧苄啶及头孢他啶较敏感，对其他多种抗生素均耐药。沙门菌则对多种抗生素敏感。结论血培养病原菌以条件致病菌为主。检出菌中除沙门菌外，均存在严重耐药问题，及时监测病原菌变化及耐药趋势以指导临床用药至关重要。     

In vitro activity of ticarcillin plus clavulanic acid (BRL 28500, 'Timentin') against ticarcillin-resistant gram-negative rods

A study was carried out to investigate the in vitro susceptibility of 211 clinical isolates of ticarcillin resistant (MICs greater than 128 micrograms/ml) Gram-negative rods to a combination of ticarcillin plus clavulanic acid. The combination demonstrated superior activity; 90% of the Proteus spp. and 50% of E. coli and Klebsiella spp. isolates were inhibited at a concentration of 64 micrograms/ml. It was 2 to 8-times more active than ticarcillin alone against E. coli, Proteus and Klebsiella spp. in half to three-quarters of the strains under test. This enhanced activity was only marginal, however, against Enterobacter, Acinetobacter, Citrobacter, Serratia and Pseudomonas spp. Against 161 ticarcillin sensitive strains the combination did not have any potentiation effect.     

In vitro activity of ceftiofur tested against clinical isolates of Escherichia coli and Klebsiella pneumoniae including extended spectrum beta-lactamase producing strains

In vitro activity of ceftiofur, a cephalosporin used in veterinary practice was compared using ceftriaxone-resistant (producing extended spectrum beta-lactamase (ESBL)) and -susceptible clinical isolates of Esherichia coli and Klebsiella pneumoniae. The ceftriaxone-susceptible isolates exhibited a lower range of ceftiofur MICs (MIC50, 0.5 mg/l, MIC90 1.0 mg/l). Those isolates known to produce an ESBL were also resistant to ceftiofur (MIC50, > or = 32 mg/l). The latter isolates were also less susceptible to other comparator drugs (cefquinome, gentamicin and trimethoprim/sulphamethoxazole) in contrast to the ceftriaxone-susceptible strains. The clinical isolates showed high correlation between ceftriaxone and ceftiofur MICs (y = 2.6 + 0.89x, r = 0.95). Using the current ceftiofur susceptible breakpoint (< or = 2 mg/l) used for veterinary practice (respiratory tract pathogens), the ESBL-producing strains of E. coli and K. pneumoniae could be accurately separated from susceptible strains. This ceftiofur breakpoint MIC corresponds to the National Committee for Clinical Laboratory Standards ESBL screening concentration for ceftriaxone set at < or = 1 mg/l = negative for ESBL production. Ceftiofur was also observed to be very active in vitro against ampicillin-resistant, non-ESBL producing enteric isolates. This new cephem appears to be very potent against the tested Enterobacteriaceae and of potential wide clinical veterinary utility.     

Transferable antibiotic resistance in Escherichia coli isolated from healthy Nigerian school children

Three hundred and ninety-six E. coli isolates obtained from apparently healthy school children in Ile-Ife, Nigeria, were tested for their susceptibility to 11 different antibiotics. Of these, only gentamicin, cefotaxime and nalidixic acid were found to have significant in vitro activity against most of the isolates. The incidence of antibiotic resistances encountered varied between 24% for trimethoprim and 55.5% for the sulphonamide. It was further observed that 47.5% of the isolates were identified as being multiply resistant, since they were simultaneously resistant to at least three different antibiotics. The 86 trimethoprim-resistant isolates tested were found to be able to transfer this resistance trait together with resistance genes of to other antibiotics, into a plamidless strain of E. coli by conjugation. Seventy-seven of the trimethoprim-resistant isolates were also found to be classifiable into the types of dihydrofolate reductases responsible for the observed resistance on the basis of hybridization experiments. The results of this study indicate that there is a large reservoir of antibiotic resistances within the community, and that the resistance genes were easily transferable to other strains even without direct exposure to antibiotics.     

In vitro activity of ceftiofur tested against clinical isolates of Escherichia coli and Klebsiella pneumoniae including extended spectrum β-lactamase producing strains

In vitro activity of ceftiofur, a cephalosporin used in veterinary practice was compared using ceftriaxone-resistant (producing extended spectrum β-lactamase (ESBL)) and -susceptible clinical isolates of Esherichia coli and Klebsiella pneumoniae. The ceftriaxone-susceptible isolates exhibited a lower range of ceftiofur MICs (MIC₅₀, 0.5 mg/l, MIC₉₀ 1.0 mg/l). Those isolates known to produce an ESBL were also resistant to ceftiofur (MIC₅₀, ≥ 32 mg/l). The latter isolates were also less susceptible to other comparator drugs (cefquinome, gentamicin and trimethoprim/sulphamethoxazole) in contrast to the ceftriaxone-susceptible strains. The clinical isolates showed high correlation between ceftriaxone and ceftiofur MICs (y=2.6+0.89x, r=0.95). Using the current ceftiofur susceptible breakpoint (≤2 mg/l) used for veterinary practice (respiratory tract pathogens), the ESBL-producing strains of E. coli and K. pneumoniae could be accurately separated from susceptible strains. This ceftiofur breakpoint MIC corresponds to the National Committee for Clinical Laboratory Standards ESBL screening concentration for ceftriaxone set at ≤1 mg/l=negative for ESBL production. Ceftiofur was also observed to be very active in vitro against ampicillin-resistant, non-ESBL producing enteric isolates. This new cephem appears to be very potent against the tested Enterobacteriaceae and of potential wide clinical veterinary utility.     

Antibiotic resistance of commensal Escherichia coli of food-producing animals from three Vojvodinian farms, Serbia

Commensal bacteria of food-producing animals are considered an important reservoir of antibiotic resistance. The aim of this study was to determine the current prevalence of resistance to 18 different antibiotics in animal commensal Escherichia coli isolated from food-producing animals from three different farms with specific modes of antimicrobial use. A very high prevalence of resistance was found to tetracycline, a moderate level to streptomycin, ampicillin, cefalothin and nalidixic acid and a low of resistance to the other tested antibiotics. Resistance to two or more antibiotics was observed among all swine E. coli, 63.2% of broiler isolates and 37.5% of cattle isolates. The results show that commensals of food-producing animals from Vojvodina region are important reservoirs of resistance to older-generation antibiotics.