产ESBLs肺炎克雷伯菌AmpC酶的检测及耐药性分析

目的了解深圳市人民医院产ESBLs肺炎克雷伯菌中产AmpC酶的情况及其耐药性。方法收集产ESBLs肺炎克雷伯菌临床株126株,应用Tris-EDTA纸片法检测AmpC酶。用琼脂稀释法测定菌株对11种抗生素的最低抑菌浓度（MIC）。结果126株ESBLs阳性的肺炎克雷伯菌中12株检出AmpC酶,检出率为9.5%。AmpC阳性菌株对头孢西丁、头孢他啶、氨曲南、氨苄西林/舒巴坦和阿莫西林/克拉维酸的耐药率达100%,对阿米卡星和哌拉西林/他唑巴坦的耐药率分别为83.3%和33.3%,其中头孢西丁、头孢他啶、氨曲南、阿莫西林/克拉维酸、阿米卡星和哌拉西林/他唑巴坦的耐药率显著高于AmpC阴性株（P〈0.05）。结论深圳市人民医院产ESBLs肺炎克雷伯菌中检出AmpC酶阳性株,其耐药性强于单产ESBLs菌株。     

ClinicalPseudomonas aeruginosa: Potential factors of pathogenicity and resistance to antimicrobials

Resistance to 17 antimicrobials, surface hydrophobicity, motility, biofilm, production ofN-acylhomoserine lactone signal molecules (N-butyrylhomoserine lactone andN-3-oxolauroylhomoserine lactone) and response to oxidative stress were analyzed in 47 clinicalPseudomonas aeruginosa strains. In addition to natural resistance, the strains demonstrated the greatest level of resistance to cefotaxime (91.5 %). Isolates in the range of 44.7–57.4 % were resistant to aminoglycosides and ciprofloxacin, of 25.5–36.2 % to cephalosporins. On the other hand, 97.9 % remained susceptible to meropenem, 93.6 % to piperacillin + tazobactam and 87.2% to piperacillin. The majority of the strains (72.3 %) manifested their hydrophilic character. Higher zones of motility showed 12 isolates (in average 54.8 mm) as compared to the others (30.2 mm). Approximately 1/3 of the strains (29.8 %) produced a higher amount of biofilm quantified by measuring the absorbance of solubilized crystal violet (0.20–0.46) than the rest of isolates (0–0.19). All but two strains producedN-3-oxolauroylhomoserine lactone and in 48.9 % of samplesN-butyrylhomoserine lactone were detected. Only four isolates with higher biofilm production showed both types of homoserine lactone. Majority of the strains (70.2 %) manifested higher resistance to H₂O₂ than the rest of the strains. The group of strains resistant to aminoglycosides and ciprofloxacin revealed a significantly higher number of hydrophobic strains (compared with the sensitive ones). In contrast, higher number of strains sensitive to aminoglycosides and ciprofloxacin or only to ciprofloxacin producedN-butyrylhomoserine lactone and biofilm (compared to the resistant ones). Such association was not found among the rest of the tested parameters. The results indicate that the resistance to antimicrobials inP. aeruginosa isolates was not generally associated with changes in the production of the pathogenicity factors.     

Antimicrobial resistance and species identification of staphylococci isolated from the meat of wild rabbits (<Emphasis Type="Italic">Oryctolagus cuniculus</Emphasis>) in Slovakia

In 2009, a total of 113 strains of staphylococci were isolated from the thigh muscles of ten hunted and 20 farmed wild rabbits (Oryctolagus cuniculus) in the Slovak Republic. Only two isolates (1.8%) possessed coagulase activity, the rest of 111 staphylococcal isolates were coagulase-negative. Among them, six isolates (5.4%) showed the production of DNase. In each isolate, resistance to eight antibiotics by means of agar dilution test was tested. Based on these results, 110 isolates were found to be resistant to at least one antibiotic. Only one isolate was susceptible to all eight antibiotics tested. Another two isolates were susceptible, however, they showed intermediate susceptibility to cefoxitin. Resistance to ampicillin (78.8%), erythromycin (58.4%), penicillin (51.3%) and oxacillin (46.0%) was found most frequently. Twenty-six isolates (23.0%) were resistant to novobiocin. On the other hand, resistance to cefoxitin (8.0%) and gentamicin (1.8%) were quite rare. Fifteen percent of isolates were resistant to one antibiotic, simultaneous resistance to two, three, four and five antibiotics was confirmed in 22.1%, 23.9%, 21.2% and 13.3% of isolates, respectively. Except for two coagulase-positive Staphylococcus aureus isolates (1.8%), seven species of coagulase-negative staphylococci were identified using the MALDI BioTyper (TM) sytem as follows: Staphylococcus warneri (45.1%), Staphylococcus epidermidis (21.2%), Staphylococcus pasteuri (13.3%), Staphylococcus xylosus (8.0%), Staphylococcus capitis (7.1%), Staphylococcus haemolyticus (1.8%) and Staphylococcus cohnii ssp cohnii (1.8%).     

Antimicrobial susceptibilities of Coagulase-Negative Staphylococci (CNS) and Streptococci from bovine subclinical mastitis cases

The prevalence and antimicrobial susceptibilities of Staphylococci and Streptococci were assessed from subclinical mastitis cases. One hundred Coagulase-Negative Staphylococci (CNS) and 34 Streptoccocci were identified. The most frequently isolated species were Staphylococcus haemolyticus (27%) and Staphylococcus simulans (24%). Susceptible CNS species revealed the highest resistance to penicillin G (58%), ampicillin (48%), neomycin (20%), and oleandomycin (14%). CNS methicillin resistance rates within 82 isolates were 21.95% and 1.22% by disk diffusion and PCR methods, respectively. These results suggested the disk diffusion method was more prone to yield false positives. Partial sequencing of the 16S rRNA region from the mecA carrying isolate (S. haemolyticus) was homologous with S. haemolyticus sequences/accessions obtained from GenBank. However, the mecA gene sequence from this isolate was more closely allied with the S. aureus mecA gene of human origins. Identical sequence data was acquired from the National Center for Biotechnology Information (NCBI) database, suggesting horizontal gene transfer between the two species. CNS β-lactamase activity within 81 isolates was 29.63%. The most frequently isolated Streptococcus species were S. uberis (52%) and S. agalactiae (15%). Oleandomycin was the least effective antimicrobial agent on these isolates with 59% susceptibility. Results indicated that CNS and Streptococci exhibited various antimicrobial resistance responses. Consequently, isolation and identification of udder pathogens in herds suffering from subclinical agents is essential to select the most effective antimicrobial agent. Moreover, multiple resistance features of methicillin resistant (MR) isolates should be considered during antimicrobial susceptibility tests.     

Characteristics ofPseudomonas aeruginosa strains isolated from urinary tract infections

Thirty-three uropathogenic strains ofPseudomonas aeruginosa were investigated for hemolytic activity in both bacterial broth culture filtrates and isolate lyzates, resistance to bactericidal activity of fresh human serum, resistance to six antibiotics and plasmid DNA profile. Twenty-four of the 33 (73%) bacterial filtrates showed lysis of rabbit erythrocytes, as did the three after guinea-pig erythrocyte treatment. Twelve of 33 isolate lysates showed in parallel lysis of both types of erythrocytes used. Serum resistance was found in 17 (52%) isolates, intermediate resistance in 15 (45%) isolates and only one isolate showed serum sensitivity. Resistance to antibiotics was detected as follows (in %): tetracycline 94, kanamycin 79, chloramphenicol 76, septrin 73, ampicillin 64, streptomycin 45, gentamicin 18. None of the isolates investigated showed resistance to colistine. With the exception of one isolate, plasmid DNA was detected in allP. aeruginosa strains.     

Aminoglycoside-modifying enzymes in clinical isolates ofAcinetobacter calcoaceticus

Aminoglycoside-modifying enzymes were identified in clinical strains ofAcinetobacter calcoaceticus subsp.anitratus (Herellea vaginicola) isolated between 1971 and 1979. Resistance to kanamycin, neomycin, and lividomycin was explained by an aminoglycoside-3′-phosphotransferase enzyme. The resistance of gentamicin was due to an aminoglycoside 3N-acetyltransferase type I enzyme which had not previously been described in this species. Several strains producing both enzymes showed resistance to kanamycin, gentamicin, lividomycin, neomycin, and sisomicin and susceptibility to tobramycin and amikacin.     

New insights into halophilic prokaryotes isolated from salting–ripening anchovies (Engraulis anchoita) process focused on histamine-degrading strains

Salted and ripened fish foods are susceptible to cause histamine poisoning. The present study focuses on microbial histamine degradation from high salted fermented fishery products to deepen our understanding about this new and growing field of research. As a result of this first study related to salted–ripened anchovies (Engraulis anchoita), fifty seven moderate and extreme halophilic microbial isolates from salt and salted–ripened anchovy processes were characterized in terms of their phenotype and histamine-degrading capacity. Only 7%—4 isolates—were able to degrade histamine. None of the histamine-degrading isolates presented proteolytic and/or lipolytic activity. One of them designated A18 was chemotactic toward histamine, an interesting property not previously reported for that chemoattractant. However, the S18 and A18 isolates, genotypically identified as Halobacterium sp. and Halomonas sp. respectively, produced indole and/or H₂S, both undesirable characteristics associated to off-flavors occurrence. On the other hand, A28 and S20, identified as Halovibrio sp. and Halobacterium sp. respectively, presented desirable properties, such as cytochrome oxidase and catalase activity, and non-production of H₂S and indole. These strains also showed characteristics previously reported as dominant in the ripened stage. The results are promising, and A28 and S20 may have the desirable features to improve the anchovy salting–ripening process.

     

Antimicrobial resistance among urinary tract infection (UTI) isolates in Europe: results from the SENTRY Antimicrobial Surveillance Program 1997

The SENTRY Antimicrobial Surveillance Program was established to monitor the occurrence and antimicrobial susceptibility of bacterial pathogens via an international network of sentinel hospitals. Twenty European hospitals referred a total of 887 urinary tract infection (UTI) isolates to the European SENTRY reference laboratory during the period October–December 1997. Ninety percent of the referred species were represented by Escherichia coli (52%), Enterococcus spp. (12%), Klebsiella spp. (7%), Proteus spp. (7%), Pseudomonas aeruginosa (7%), and Enterobacter spp. (5%). The susceptibility of E. coli isolates to penicillins was less than 60%, while almost all of the isolates were susceptible to piperacillin/tazobactam (98% susceptibility), cephalosporins (98%), and carbapenems (100%). Amikacin was the best aminoglycoside (99.8% susceptibility). The susceptibility to quinolones was only 88–89%, with highest levels of resistance observed for isolates from Portugal, Italy, England, The Netherlands, and some centers in France, Spain, and Poland. The susceptibility of Klebsiella spp. to the newer generations of cephalosporins was 82–95% and to the carbapenems 100%. Amikacin was again the best aminoglycoside (94% susceptibility). The susceptibility of Enterobacter spp. to any ß-lactam antibiotic was poor, except for the carbapenems (100% susceptibility) and cefepime (90% susceptibility), while the susceptibility to aminoglycosides was 80–89%. Proteus spp. showed complete susceptibility to cefepime, ceftriaxone, the carbapenems, and piperacillin/tazobactam, while the susceptibility of P. aeruginosa isolates was poor, with best results for the carbapenems (susceptibility 89%), piperacillin/tazobactam (susceptibility 84%), and amikacin and ticarcillin (susceptibility to both 80%). Enterococcus spp. showed the highest susceptibility to vancomycin (98%), teicoplanin (98%), and ampicillin (94%).     

Incidence of antimicrobial resistance among Enterobacteriaceae isolated in Riyadh

The antimicrobial resistance of 1,018 isolates of Enterobacteriaceae isolated from fecal specimens of the urban population of Riyadh, Saudi Arabia, was studied. Resistance to 1 or more of 10 antimicrobial agents was encountered in 50.2% of the isolates. Of the isolates tested,Escherichia coli (0.8%) andKlebsiella species (1.6%) were found resistant to seven antimicrobial agents simultaneously: ampicillin, chloramphenicol, kanamycin, colistin, streptomycin, tetracycline, and carbenicillin. Resistance to nalidixic acid was encountered in only 0.68% of theE. coli isolates. No isolate was found to be resistant to gentamicin. Eighty-six of the resistant strains were tested for their ability to transfer their resistance. Forty percent were able to do so withE. coli K-12.     

<Emphasis Type="Italic">In Vitro</Emphasis> susceptibility to selected antibiotics in bacteria of the <Emphasis Type="Italic">Bacteroides fragilis</Emphasis> group

Susceptibility of strains of Bacteroides fragilis group (1284 isolates from cancerous and noncancerous patients in 1994–2004) showed an increase in resistance toward some antibiotics (by 9 % toward penicillin and 8 % toward clindamycin) compared with the resistance level of 10 years ago. The increase in resistance was not detected in the case of ampicillin + sulbactam and metronidazole.     

Antibiotic susceptibility, serum response and surface properties of Klebsiella species

Altogether 130 clinical isolates of five Klebsiella species (K. pneumoniae, K. planticola, K. oxytoca, K. ornithinolytica and K. terrigena) were characterized, for their susceptibility to five antibiotics, for susceptibility to serum bactericidal activity and for their hydrophobic properties. All strains exhibited ampicillin resistance. Ampicillin/sulbactam, gentamicin and ofloxacin showed effectiveness in 63.1, 67.7 and 71.5% of the Klebsiella isolates. K. planticola manifested the highest level of resistance to these antibiotics. The majority of Klebsiella strains (93.9%) were susceptible to cefuroxime. Sixty-four strains (49.2%) were serum resistant and intermediate serum sensitivity was shown by 57 strains (43.8%). A high percentage of serum resistant strains (65%) was found in K. planticola. Moderately hydrophobic properties determined by adherence of bacteria to xylene were demonstrated in 25 strains (19.2%).     

Antibiotic resistance of Salmonella strains isolated from children living in the wastewater-spreading field of Marrakesh city (Morocco)

A total of 813 Salmonella strains isolated from raw wastewater and stool specimens of inpatient children, living in the wastewater-spreading field of Marrakesh city, were examined for their susceptibility to 15 antimicrobial agents. All the isolates were susceptible to cefotaxime, and almost of them showed susceptibility to gentamicin (99.88%), trimethoprim-sulphamethoxazole (98.04%), nalidixic acid (98.04%), kanamycin (97.30%), trimethoprim (97.18%), and chloramphenicol (96.07%). The highest levels of antibiotic resistance were obtained for cephalothin (29.27%), amoxicillin (26.44%), sulphamethoxazole (26.07%), and ampicillin (25.21%). The strains from the serogroup B showed the highest antibiotic resistance frequencies. The percentage of polyresistant strains (36.09%) was significantly higher than that of monoresistant isolates (15.49%). The incidence of drug resistance in Salmonella isolates from stools was significantly higher than in those isolated from wastewater.     

Incidence of resistance to tetracycline,chloramphenicol and ampicillin amongSalmonella species isolated in The Netherlands in 1965 and 1966

In 1965 and 1966 respectively 9628 and 10467Salmonella strains were screened for resistance to tetracycline and chloramphenicol. In 1965 the major half of the strains were also tested for ampicillin resistance and in 1966 all strains passed this test. In 1965 20.9% and in 1966 21.7% were found resistant, mainly to tetracycline. The incidence of resistance to chloramphenicol remained low (less than 1%). By far the majority of the resistant strains belonged toS. typhi murium andS. panama. The rate of resistance in the former organism remained nearly equal to that observed in 1963 – 1964, whereas inS. panama it has diminished.Ampicillin-resistant strains were found in as many as 23 different types ofSalmonella. In 8 types in which ampicillin resistance was found, only animal strains were concerned. These findings may represent cases of primary ampicillin resistance. In the human strains ofSalmonella the incidence of ampicillin resistance increased from 11.6% in 1965 to 15.3% in 1966.     

环丙沙星耐药的铜绿假单胞菌药敏情况分析

目的了解对环丙沙星耐药的铜绿假单胞菌的药敏情况。方法细菌的鉴定及药敏试验,均采用法国生物梅里埃公司的VITEK2微生物鉴定与药敏系统,选择经VITEK2测定耐环丙沙星的铜绿假单胞菌(耐药株)68株及对环丙沙星敏感的铜绿假单胞菌(敏感株)67株,统计分析两者对亚胺培南、阿米卡星、庆大霉素、头孢他啶、哌拉西林和哌拉西林他唑巴坦等几种临床上常用抗生素的药敏情况。结果耐药株对以上6种抗生素的敏感率分别为亚胺培南706%,阿米卡星206%,庆大霉素191%,头孢他啶279%,哌拉西林632%,哌拉西林他唑巴坦721%。而敏感株对6种抗生素的敏感率则分别为925%、328%、687%、657%、881%与896%,明显高于耐药株,经χ2检验,除阿米卡星005相似文献   

Drug resistance of 100 clinical strains of Enterococcus spp

The aim of this study was to evaluate the drug susceptibility of 100 Enterococcus spp. strains isolated from patients hospitalized in State Clinical Hospital No 1 in Warsaw. All strains were identified (API 20 STREP) and their susceptibility to antibiotics was tested (ATB STREP) in automatic ATB system. Additionally, PYRase activity, beta-lactamase production (in nitrocefin test), MICs for vancomycin and teicoplanin (E test), HLAR--high level aminoglycoside resistance and susceptibility to vancomycin, teicoplanin, piperacillin and piperacillin/tazobactam (disc diffusion method) were determined. E. faecalis ATCC 29212 was used as the control strain. Fifty E. faecalis, 45 E. faecium, 2 E. casseliflavus, 2 E. durans and 1 E. avium strain were cultured. All strains were PYRase-positive and beta-lactamase-negative. Ten isolates demonstrated intermediate susceptibility to vancomycin (6--E. faecalis and 4--E. faecium). One E. faecalis strain was intermediately susceptible to both glycopeptides. One E. casseliflavus strain showed low-level resistance to vancomycin, but this strain was susceptible to teicoplanin--phenotype Van C. HLAR strains were found among 31 E. faecalis and 40 E. faecium strains. 48 E. faecalis strains were susceptible to piperacillin and 49 to piperacillin/tazobactam. Whereas, 41 E. faecium were resistant to both these drugs. Thirty six per cent of isolates were resistant to penicillin and ampicillin, 73% to erythromycin, 87% to tetracycline, 89% to lincomycin and 56% to nitrofurantoin. Some discrepancies were noticed between the results of different methods applied for susceptibility testing--ATB system, E test and disc diffusion. These discrepancies concerned HLAR detection and susceptibility to glycopeptides determination. The best methods were: disc-diffusion for HLAR detection and E test for determination of resistance to vancomycin and teicoplanin. Increasing resistance to antimicrobial agents is observed in clinical Enterococcus spp. isolates cultured in our laboratory, especially in E. faecium strains. It is necessary to control the dissemination of multiresistant Enterococcus spp. strains in hospital wards.     

Characterization of novel diesel-degrading strains <Emphasis Type="Italic">Acinetobacter haemolyticus</Emphasis> MJ01 and <Emphasis Type="Italic">Acinetobacter johnsonii</Emphasis> MJ4 isolated from oil-contaminated soil

The diesel-degrading strains, designated as MJ01 and MJ4, were isolated from oil-contaminated soil in Daejeon (South Korea) and were taxonomically characterized using a polyphasic approach and their diesel oil degradation abilities were analyzed. The isolates MJ01 and MJ4 were identified as Acinetobacter haemolyticus and Acinetobacter johnsonii, respectively, based on their 16S rDNA gene sequences, DNA–DNA relatedness, fatty acid profiles and various physiological characteristics. Strains MJ01 and MJ4 were able to use diesel oil as the sole carbon and energy source. Both strains could degrade over 90% of diesel oil with an initial concentration of 20,000 mg/l after incubation for 7 days, the most significant degradation occurred during the first 3 days. To our knowledge, this is the first report on diesel oil-degrading microorganisms among bacterial strains belonging to A. haemolyticus and A. johnsonii.     

Studies of Pseudomonas aeruginosa Infections Among Hospitalized Patients

A rapid identification method of glucose nonfermentative gram-negative rods was established and 320 strains isolated were divided into five groups according to their characteristics in pigmentation, acid from glucose, cytochrome oxidase activity and motility. Further characterization of the strains in each group resulted in the identification that the strains in group I were Pseudomonas aeruginosa, strains in group II, P. aeruginosa and Pseudomonas putida. Achromogenic strains of P. aeruginosa were classified into group III, Pseudomonas maltophilia, Pseudomonas alcaligenes and Alcaligenes faecalis into group IV and Acinetobacter calcoaceticus (Acinetobacter anitratus and Achromobacter lwoffii) in group V. When fluorescent pigment production was taken as a standard, 259 out of 263 chromogenic strains were identified as P. aeruginosa and the remaining four were P. putida. Whereas forty-five achromogenic strains included twenty-four A. calcoaceticus, eight P. aeruginosa, six A. faecalis, five P. maltophilia and two P. alcaligenes. From May 1970 to June 1971, 368 strains of glucose nonfermentative rods were isolated from clinical specimens sent to the Central Laboratories of Tohoku University Hospital and three fourth (286/368) of the isolates were P. aeruginosa     

广州地区儿童血培养病原菌的分布及耐药性研究

目的探讨儿童血培养病原菌的分布特点及其耐药情况,为临床诊疗提供参考。方法对广州市儿童医院2005年至2006年临床各科室送检血液标本所分离病原菌的分布及药敏结果进行回顾性分析。结果共检出385株病原菌,其中革兰阳性菌208株,占54．0％,革兰阴性菌164株,占42．6％,真菌13株,占3．4％。分离率前6位的病原菌依次为凝固酶阴性葡萄球菌（CNS,35．8％）、肺炎克雷伯菌（8．8％）、不动杆菌（5．5％）、大肠埃希菌（4．9％）、铜绿假单胞菌（4、7％）、金黄色葡萄球菌（4．4％）。病原菌的病区分布特点：儿科重症监护病房以不动杆菌等非发酵菌为主要分离菌（占41．7％）,新生儿重症监护病房以CNS为主（40．5％）,血液病区以肠杆菌科细菌为主（35．7％）,新生儿病房及传染病房均以CNS为主要分离菌。CNS对青霉素、氨苄西林、红霉素耐药率均超过80％,但对万古霉素、替考拉宁和阿米卡星敏感,MRCNS检出率达72.5％。肠杆菌科细菌对哌拉西林、氨苄西林、头孢噻肟及头孢哌酮的耐药率为50％～100％,但对亚胺培南、阿米卡星和诺氟沙星耐药率较低。不动杆菌对广谱青霉素、第3代头孢菌素、氨曲南及庆大霉素的耐药率较高而对亚胺培南、头孢哌酮／舒巴坦较为敏感。结论凝固酶阴性葡萄球菌是广州地区儿童败血症最主要的病原菌。不同病区检出病原菌种类有较大差异。根据病原菌种类及药敏结果合理应用抗菌药是有效控制感染和减少耐药菌株产生的重要手段。     

Murein degradation inEscherichia coli infected with bacteriophage ϕX174

LY 127935 (moxalactam), a new 1-oxa cephalosporin, was evaluated in vitro in agar dilution testing against 177 different clinical isolates of cephalothin-resistant Enterobacteriaceae andPseudomonas aeruginosa in parallel with amikacin, cephalothin, cefoxitin, and cefamandole. Ninety percent of the isolates were also gentamicin-resistant by disk testing. LY 127935 showed a very high degree of activity against cephalothin-resistant organisms but amikacin was more active in vitro, particularly againstP. aeruginosa. Cefoxitin and cefamandole were consistently less active than either LY 127935 or amikacin.     

Antimicrobial resistance among Salmonella serovars isolated from different sources in Brazil during 1978–1983

A total of 748 Salmonella strains (97 serovars) isolated from human (291), animal (119), environmental (141), food (102) and animal feed (95) sources were examined for resistance to 9 antimicrobial agents. Most of the human isolates were from hospitalized patients (282). An overall resistance rate of 98.8% was determined with 100% for human and environmental isolates. Resistance to sulfadiazine (87.7%) was most common, followed by streptomycin (61.2%), ampicillin (39%) and trimethoprim-sulphamethoxazole (37.9%). Fifty one different resistance patterns were identified with Su (164 strains), Su-Sm (122) and Su-Sm-Tc-Cm-Km-Ap-Nx-Gm-Tm (95) predominating, the latter occurring only in human isolates. Multiple resistance was most frequently found among human isolates, particularly in S. derby and S. typhimurium strains. The relationship between antibiotic resistance, serovar and source of isolation of the Salmonella strains is discussed.