In vitro susceptibility of recent antibiotic-resistant urinary pathogens to ertapenem and 12 other antibiotics

Background: The treatment of complicated urinary tract infections may require the use of a parenteral antibiotic with potent activity against the most common urinary pathogens. Ertapenem is a broad-spectrum 1beta-methyl carbapenem with a long plasma half-life that allows administration of a single daily dose. METHODS: The purpose of this work was to test the in vitro susceptibility to ertapenem, ampicillin, cefazolin, cefuroxime, cefotaxime, co-amoxiclav, piperacillin/tazobactam, imipenem, gentamicin, amikacin, fosfomycin, ciprofloxacin and co-trimoxazole of 482 strains of urinary pathogens of the family Enterobacteriaceae isolated from patients in the community of Madrid (40% from males). The distribution was as follows: Escherichia coli (n = 315), Proteus mirabilis (n = 42), Klebsiella spp. (n = 14) and AmpC-producing Enterobacteriaceae (n = 111). The strains studied were selected based on their resistance to quinolones and aminoglycosides, and their production of extended-spectrum beta-lactamases (ESBLs) or AmpC-type beta-lactamases. RESULTS: All the strains were susceptible to ertapenem, imipenem and amikacin. The MIC(90) of ertapenem ranged from a minimum of 0.03 mg/L for Proteus vulgaris and a maximum of 1 mg/L for Enterobacter spp. Ertapenem was the most active of all drugs tested in all cases. On comparing antibiotic resistance among ESBL-producing strains of E. coli (n = 35) and E. coli strains not producing ESBLs (n = 280), statistically significant differences were obtained for ciprofloxacin (P = 0.002) and gentamicin (P = 0.011). Regarding ertapenem, only a slight increase in MIC(50) was seen, the value being 0.015 mg/L for strains not producing ESBLs versus 0.03 mg/L for ESBL-producing strains. CONCLUSIONS: In view of its significant antibiotic potency against antibiotic-resistant Enterobacteriaceae, ertapenem may constitute a good therapeutic alternative in urinary infections caused by these pathogens.     

Emergence of Enterobacteriaceae producing extended-spectrum beta-lactamases (ESBLs) in the community

Enterobacteriaceae, especially Klebsiella spp. producing extended-spectrum beta-lactamases (ESBLs) such as SHV and TEM types, have been established since the 1980s as a major cause of hospital-acquired infections. Appropriate infection control practices have largely prevented the dissemination of these bacteria within many hospitals, although outbreaks have been reported. However, during the late 1990s and 2000s, Enterobacteriaceae (mostly Escherichia coli) producing novel ESBLs, the CTX-M enzymes, have been identified predominantly from the community as a cause of urinary tract infections. Resistance to other classes of antibiotics, especially the fluoroquinolones, is often associated with ESBL-producing organisms. Many clinical laboratories are still not aware of the importance of screening for ESBL-producing Enterobacteriaceae originating from the community. A heightened awareness of these organisms by clinicians and enhanced testing by laboratories, including molecular surveillance studies, is required to reduce treatment failures, to limit their introduction into hospitals and to prevent the spread of these emerging pathogens within the community.     

Antimicrobial activity of tigecycline tested against nosocomial bacterial pathogens from patients hospitalized in the intensive care unit

The antimicrobial activity of tigecycline and selected antimicrobials was evaluated against bacterial pathogens isolated from patients hospitalized in intensive care units (ICUs) worldwide. A total of 9093 isolates were consecutively collected in >70 medical centers in North America (4157), South America (1830), Europe (3034), and the Asia-Australia (72) areas. The isolates were collected from the bloodstream (68.5%), respiratory tract (13.6%), skin/soft tissue (5.5%), and urinary tract (2.0%) infections in the 2000-2004 period, and susceptibility was tested by reference broth microdilution methods. The most frequently isolated pathogens were Staphylococcus aureus (32.1%), Enterococcus spp. (13.7%), coagulase-negative staphylococci (CoNS; 13.0%), Pseudomonas aeruginosa (8.4%), and Escherichia coli (7.9%). All Gram-positive pathogens (5665) were inhibited at < or =1 microg/mL of tigecycline. Resistance to oxacillin was detected in 43.5% of Staphylococcus aureus and in 85.0% of CoNS, and resistance to vancomycin was observed in 18.6% of enterococci. Tigecycline was very active against Enterobacteriaceae (1876 strains tested) with an MIC90 of < or =1 microg/mL, except for Serratia spp. (2 microg/mL). Extended-spectrum beta-lactamase (ESBL) phenotype was detected in 10% of E. coli and 31% of Klebsiella spp., whereas 28% of Enterobacter spp. were resistant to ceftazidime (AmpC enzyme production). These resistance phenotypes did not adversely affect tigecycline activity. Tigecycline and trimethoprim/sulfamethoxazole were the most active compounds against Stenotrophomonas maltophilia (MIC90, 2 and 1 microg/mL respectively). Tigecycline was also active against Acinetobacter spp. (MIC90, 1 microg/mL), but P. aeruginosa showed decreased susceptibility to tigecycline (MIC90, 16 microg/mL). In summary, isolates from ICU patients worldwide showed high rates of antimicrobial resistance. The most alarming problems detected were vancomycin resistance among enterococci, ESBL-mediated beta-lactam resistance and fluoroquinolone resistance among Enterobacteriaceae, and carbapenem resistance among P. aeruginosa and Acinetobacter spp. Tigecycline exhibited potent in vitro activity against most of clinically important pathogenic bacteria (except P. aeruginosa) isolated from ICU patients and may represent an excellent option for the treatment of infections in this clinical environment.     

肿瘤患者下呼吸道感染常见病原菌的分布与耐药性研究

目的 研究肿瘤患者下呼吸道感染常见病原菌的分布与耐药现状,为临床合理使用抗菌药物提供科学依据.方法对2 037例下呼吸道感染肿瘤患者深部咳出的痰标本,按照<全国临床检验操作规程>进行病原菌分离、鉴定,药敏试验采用纸片扩散法(K-B法),并按 CLSI/NCCLS规定的标准进行.结果 病原菌的阳性检出率为70.3%,其中G-杆菌占40.9%,G+球菌占29.5%,真菌占28.7%;大肠埃希菌、凝固酶阴性葡萄球菌(CNS)和白色假丝酵母菌分别为G-杆菌、G+球菌和真菌的首位;大肠埃希菌和肺炎克雷伯菌产超广谱β-内酰胺酶(ESBLs) 菌株分别为52.7%和30.8%,阴沟肠杆菌产AmpC酶菌株占16.9%,铜绿假单胞菌产金属β-内酰胺酶(MBL)菌株占9.8%;甲氧西林耐药株分别占金黄色葡萄球菌(SAU)和CNS的38.3%和70.5%,未发现万古霉素耐药的耐甲氧西林SAU(MRSA)和耐甲氧西林CNS(MRCNS);万古霉素、碳青霉烯类药物仍然分别是G+球菌和肠杆菌科细菌最敏感的药物.结论 本院肿瘤患者下呼吸道感染以白色假丝酵母菌位居第一,对伊曲康唑耐药性较严重;细菌耐药性以产ESBLs大肠埃希菌、肺炎克雷伯菌,产AmpC酶阴沟肠杆菌,产MBL铜绿假单胞菌,鲍曼不动杆菌,MRSA和MRCNS比较严重,其他细菌也分别存在不同程度的耐药情况.临床微生物实验室应继续加强耐药性检测,为临床合理选用抗菌药物提供科学依据.     

尿液标本中大肠埃希菌产超广谱β-内酰胺酶的检测

目的：分析尿液标本中大肠埃希菌的耐药性及其产超广谱β-内酰胺酶（ESBLs）情况，指导临床用药。方法：对124例泌尿系感染患者尿液标本中的大肠埃希菌用纸片扩散法进行抗生素敏感试验，纸片扩散法表型确证试验检测ESBLs。结果：有58株大肠埃希菌产ESBLs，占46．8％．引起泌尿系感染的大肠埃希菌对亚胺培南的耐药率〈1．7％，对呋喃妥因的耐药率〈12％．可作为治疗泌尿系感染的首选与次选药物。产ESBLs菌株对头孢西丁、头孢哌酮／舒巴坦、环丙沙星、氧氟沙星、左旋氧氟沙星和阿米卡星的耐药率比非产ESBLs菌株明显升高（P〈0．01）。男性患者产ESBLs菌株的检出率明显高于女性患者（P〈0．01）。结论：尿路感染应检测ESBLs并根据抗生素敏感试验选择敏感药物进行合理用药。     

尿路感染大肠埃希菌耐药特点与种系分型和遗传相关性分析

目的分析尿路感染大肠埃希菌的耐药特点、种系分型和遗传相关性,并对比其在医院和社区感染中的差异。方法对2010年非重复分离185株尿路感染大肠埃希菌进行敏感性测定、超广谱β-内酰胺酶（ESBLs）筛查、种系分型、同源性及统计学分析。结果细菌对多种药物的耐药率〉49．0％。185株细菌均有很大的遗传多样性,产酶率为78．4％。D型大肠埃希菌最为常见（49．7％）,其ESBLs的产生率与头孢噻肟等的耐药性相关（P〈0．05）。上述各因子在医院和社区感染菌株中差异无统计学意义（P〉0．05）。结论本研究尿路感染主要由D型大肠埃希菌引起,这些细菌呈遗传多样性,高产ESBLs,对多种抗菌药物耐药。     

Dominance of CTX-M group 1 beta-lactamase enzymes in ESBL producing E. coli from outpatient urines in neighboring regions of Austria and Italy

The importance of extended spectrum β-lactamases (ESBL) is increasing worldwide. ESBLs of the CTX-M type are on the rise in Europe, not only in the hospital environment but also in outpatients. Therefore we performed a comparative pilot study including ESBL producing Escherichia coli isolated from outpatients suffering from urinary tract infections, 28 from Innsbruck, Austria, and 34 from Bolzano, Italy. Using established PCR methods we detected in nearly 90% of ESBL producing E. coli isolates CTX-M group 1 enzymes and only a few group 2 or group 9 enzymes. bla (TEM), bla (OXA-1) and aminoacyltransferase aac(6')-lb were significantly more frequent in the Austrian region, where also bla (SHV )was found in one isolate. In 2009 the overall prevalence of ESBL in E. coli causing urinary tract infection in outpatient samples was 7.6% in a local laboratory in Innsbruck and 5% in Bolzano. Additionally, we investigated plasmid-mediated qnr genes which can contribute to quinolone resistance, qnrA was found in an AmpC producing E. coli from Innsbruck and qnrS in two ESBL producers from Bolzano. Data confirmed that ESBL-producing E. coli have emerged as important pathogens in urinary tract infections of outpatients in both regions.     

老年患者泌尿系统感染致病菌及其耐药性分析

目的调查老年患者泌尿系统感染致病菌及其耐药性，为临床合理使用抗生素提供依据。方法对428例老年患者中段尿标本进行细菌培养及耐药性监测。结果共检测出病原菌435株，其中革兰阴性杆菌占61．8％，革兰阳性球菌占25．1％，真菌占10．3％；老年女性革兰阴性杆菌的感染率显著高于男性（P〈0．01）；革兰阴性及阳性细菌中分别以大肠埃希菌（39．1％）和肠球菌属（16．3％）最多。产超广谱β-内酰胺酶（ESBLs）的大肠埃希菌对亚胺培南、哌拉西林-他唑巴坦、呋喃妥因、氨卞西林-舒巴坦、阿米卡星的耐药率低；肠球菌属细菌对万古霉素、利奈唑烷均100％敏感；葡萄球菌属细菌耐甲氧西林株达90．6％。结论老年患者泌尿系统感染以革兰阴性菌为优势菌株，细菌耐药性监测对指导临床合理用药具有重要意义。     

Activity of faropenem against cephalosporin-resistant Enterobacteriaceae

BACKGROUND: There is a need for new oral agents active against extended-spectrum beta-lactamase (ESBL) producers, as these increasingly cause community-onset infections. We therefore evaluated faropenem, a penem in Phase III development, against recently collected oxyimino-cephalosporin-resistant bacteria. METHODS: We tested 847 consecutive cephalosporin-resistant Enterobacteriaceae collected at 16 centres in South-East England in 2004, 501 of them with CTX-M enzymes; we also tested reference strains and transconjugants with acquired beta-lactamases and various modes of AmpC expression. MICs were determined by the BSAC agar dilution method. RESULTS: Modal MICs of faropenem for Escherichia coli or Klebsiella spp. with CTX-M or non-CTX-M ESBLs or high-level AmpC enzyme were 0.5-1 mg/L, with over 95% of producers susceptible to 相似文献   

尿路感染常见病原菌分析

目的了解本院尿路感染常见病原菌的分布及耐药情况,为临床合理选用抗菌药物提供依据。方法对本院2008年1～12月住院及门诊患者尿培养阳性非重复分离的164株病原菌进行回顾性分析。结果尿路感染常见病原菌以革兰阴性杆菌为主,有125株（76.2%）,其中尤以大肠埃希菌分离率最高,有104株（63.5%）;革兰阳性球菌35株（21.4%）;真菌4株（2.4%）。大肠埃希菌的产超广谱β-内酰胺酶（ESBLs）检出率为60.6%（63/104）,产ESBLs株大肠埃希菌的耐药率明显高于非产ESBLs株;革兰阳性球菌耐药情况严重。结论尿路感染常见病原菌以革兰阴性杆菌为主,临床应重视病原学检查,根据药敏试验结果合理使用抗菌药物。     

Ofloxacin, a new broad-spectrum fluoroquinolone. Results from a Multicenter, National Comparative Activity Surveillance Study. The Ofloxacin Surveillance Group.

Ofloxacin, a newer broad-spectrum fluoroquinolone, was evaluated against 6967 clinical isolates in a multicenter surveillance trial using a standardized disk diffusion method. Thirty-five geographically diverse laboratories contributed zone diameter results for two (ofloxacin and ciprofloxacin) to five (ofloxacin, ciprofloxacin, ampicillin, cefaclor, and cefixime) antimicrobial agents, depending on the site of infection. Ofloxacin was determined to have the widest spectrum of activity and potential empiric use (90.6%, range 87.1%-92.2%) for respiratory tract, urinary tract, and cutaneous infections. The spectrum was superior to ciprofloxacin (average 85.3% versus three sites), ampicillin (35.5%, respiratory tract), cefaclor (60.5%, respiratory tract), cefixime (60.9%, respiratory tract), and norfloxacin (87.3%, urinary tract). Strains resistant to ofloxacin (35 isolates, 0.5%) were confirmed by reference laboratory tests and cross resistance was observed among several current and investigational fluoroquinolone agents. The species most often found to be fluoroquinolone resistant among the Enterobacteriaceae were Klebsiella pneumoniae, Serratia marcescens, and Providencia spp. Monitoring for increasing fluoroquinolone resistance should be considered as greater use of drugs in this class develops. By these cited statistics, ofloxacin appears to have a broad and balanced spectrum of potential use, particularly against Gram-positive pathogens.     

Potency and spectrum of garenoxacin tested against an international collection of skin and soft tissue infection pathogens: report from the SENTRY antimicrobial surveillance program (1999-2004)

The spectrum and potency of garenoxacin, a novel des-F(6)-quinolone, against a large international collection (11723 strains) of Gram-positive and Gram-negative bacterial pathogens that cause skin and soft tissue infections (SSTIs) were evaluated for the years 1999 to 2004. Consecutive nonduplicate bacterial isolates were collected from patients with documented community-acquired or nosocomial SSTI in >70 medical centers participating in the SENTRY Antimicrobial Surveillance Program in North America (37.4%), Europe (26.7%), Latin America (16.7%), and the Asia-Pacific region (19.2%). All isolates were tested using the reference broth microdilution methods against garenoxacin, ciprofloxacin, levofloxacin, gatifloxacin, moxifloxacin, and representative comparator agents used for the empiric or directed therapy for SSTI. Ranking pathogens producing SSTI during these years included Staphylococcus aureus (42.8%), Pseudomonas aeruginosa (11.1%), Escherichia coli (9.0%), Enterococcus spp. (7.3%), Klebsiella spp. (4.8%), Enterobacter spp. (4.7%), beta-hemolytic streptococci (4.3%), coagulase-negative staphylococci (4.0%), Proteus mirabilis (2.5%), and Acinetobacter spp. (2.1%). Garenoxacin was the most potent agent tested against S. aureus and was at least 2-fold more active than gatifloxacin (MIC(50), 0.06 mg/L) and 8-fold more active than levofloxacin (MIC(50), 0.25 mg/L). Furthermore, garenoxacin was 2- to 8-fold more potent than the fluoroquinolones against beta-hemolytic and viridans group streptococci, as well as up to 4-fold more active against enterococci. Garenoxacin was largely comparable with the comparator fluoroquinolones against E. coli, Klebsiella spp., and Acinetobacter spp., but it is less active than these agents against P. aeruginosa. In summary, garenoxacin was documented to be the most potent quinolone when tested against key Gram-positive pathogens (S. aureus, beta-hemolytic streptococci, viridans group streptococci, and enterococci) and was similar in activity to these agents against other species (Enterobacteriaceae and Acinetobacter spp.). These in vitro data suggest that garenoxacin warrants further clinical studies in SSTI, especially against staphylococci and streptococcal pathogens.     

Prevalence and mechanisms of cephalosporin resistance in Enterobacteriaceae in London and South-East England

OBJECTIVES: To investigate the molecular epidemiology of Enterobacteriaceae producing extended-spectrum beta-lactamases (ESBLs) in London and South-East England. METHODS: A prospective study involving 16 hospital microbiology laboratories in London and South-East England was undertaken over a 12 week period. Each laboratory submitted up to 100 consecutive cephalosporin-resistant Enterobacteriaceae isolates judged clinically significant by microbiology staff. Centralized testing was undertaken to confirm organism identification and cephalosporin resistance and to analyse resistance mechanisms. RESULTS: The predominant mechanism of cephalosporin resistance in isolates from both hospital and community settings was the production of CTX-M-type ESBLs, with CTX-M-producing Escherichia coli as the most numerous resistant organism overall. Other major mechanisms of cephalosporin resistance included production of non-CTX-M ESBLs and AmpC beta-lactamases. Most ESBL (both CTX-M and non-CTX-M) producers were multiply resistant to non-beta-lactam antibiotics, including trimethoprim, ciprofloxacin and gentamicin. CONCLUSIONS: CTX-M enzymes, which were unrecorded in the UK prior to 2000, have become the major mechanism of cephalosporin resistance in Enterobacteriaceae in South-East England. E. coli has overtaken Klebsiella and Enterobacter spp. to become the major host for ESBLs. Due to the multiple antibiotic resistance exhibited by many ESBL-producers, these changes have major implications for antimicrobial therapy.     

泌尿系感染病原菌的分布及耐药性分析

目的探讨本地区引起泌尿系感染的病原菌及其耐药性,为临床治疗提供依据。方法用常规方法分离鉴定病原菌,用K-B法进行药物敏感试验。结果302株病原菌中革兰阴性杆菌252株,占83%,主要为大肠埃希菌和肺炎克雷伯菌。革兰阳性球菌38株,占13%。真菌12株,占4%。大肠埃希菌产ESBLs检出率为43.8%,肺炎克雷伯菌产ESBLs检出率为57.1%,耐甲氧西林凝固酶阴性葡萄球菌(MRCNS)的检出率为56.2%,MRSA的检出率为22.2%。结论了解引起泌尿系感染病原菌的分布及耐药性监测,合理使用抗菌药物以减少耐药菌株的产生和医院感染的爆发流行。     

In vitro susceptibilities of aerobic and facultative Gram-negative bacilli isolated from patients with intra-abdominal infections worldwide: the 2003 Study for Monitoring Antimicrobial Resistance Trends (SMART)

OBJECTIVES: The SMART (Study for Monitoring Antimicrobial Resistance Trends) surveillance programme was begun in 2002 to monitor antimicrobial resistance trends among aerobic and facultative Gram-negative bacilli (GNB) isolated from intra-abdominal infections worldwide. METHODS: In 2003, 74 medical centres from 23 countries collected isolates for testing. Antimicrobial susceptibility testing was performed using broth microdilution according to the NCCLS guidelines for MIC testing. RESULTS: A total of 5658 aerobic and facultative GNB were isolated from intra-abdominal infections. Enterobacteriaceae composed 84% of the total isolates. Among the agents tested, the carbapenems were the most consistently active against the Enterobacteriaceae. E. coli was the most common isolate (46%), and the susceptibility rate to the quinolone (70-90% susceptible), cephalosporin (80-97% susceptible), aminoglycoside (77-100% susceptible) and carbapenem (99-100% susceptible) agents tested varied among geographic regions, with isolates from the Asia/Pacific region generally being the most resistant. Extended-spectrum beta-lactamases (ESBLs) were detected phenotypically in 9% of E. coli, 14% of Klebsiella spp., and 14% of Enterobacter spp. worldwide. ESBL producers generally had a more antibiotic-resistant profile than non-ESBL producers. CONCLUSIONS: Antimicrobial resistance among GNB isolated from intra-abdominal infections is a problem worldwide, especially in the Asia/Pacific region. The carbapenems ertapenem, meropenem and imipenem are highly active in vitro against Enterobacteriaceae isolated from intra-abdominal sites, including organisms that produce ESBLs.     

广州地区下呼吸道感染常见病原菌的分布与耐药性

目的 :探讨广州地区下呼吸道感染常见病原菌分布与耐药情况。方法 :收集广州地区 13所医院下呼吸道感染患者痰标本分离的 1778株病原菌 ,按美国国家临床实验室标准委员会 (NCCLS)标准进行药敏试验。结果 :主要菌群有铜绿假单胞菌 (2 2 .7% )、克雷伯菌属 (15 .8% )、不动杆菌属 (12 .5 % )和肠杆菌属 (10 .5 % )等。甲氧西林耐药株分别占金黄色葡萄球菌和凝固酶阴性葡萄球菌的 75 .7%和 92 .9% ,未发现万古霉素耐药株。大肠埃希菌和克雷伯菌属产超广谱 β内酰胺酶 (ESBLs)的发生率是 4 6 .8%和 37.0 % ,产ESBLs菌株对各种抗菌药物的耐药率明显高于不产ESBLs菌株。铜绿假单胞菌对头孢哌酮 舒巴坦、头孢他啶、头孢吡肟和亚胺培南的敏感率较高。结论 :广州地区下呼吸道感染主要病原菌是革兰阴性杆菌 ,其对常用抗菌药物耐药性较高 ,开展细菌耐药性监测十分重要。     

Susceptibility of Recent Bacterial Isolates to Cefdinir and Selected Antibiotics among Children with Urinary Tract Infections

Background: Cefdinir, an extended‐spectrum cephalosporin administered orally, is approved by the U.S. Federal Drug Administration for treatment of skin and respiratory tract infections. During the last two years at the authors' institution, this agent has been used as an off‐label treatment for urinary tract infections in children. Objectives: To evaluate antimicrobial susceptibility testing data in children to determine whether there is support for this prescribing practice. Methods: In this retrospective study (2003–2004), the authors compared the susceptibility patterns of urinary pathogens to cefdinir and selected antibiotics in children who were evaluated for urinary tract infections in an urban tertiary academic pediatric emergency department. Pathogens (community acquired vs. opportunistic or nosocomial) were categorized as susceptible, indeterminate, or resistant on the basis of antibiotic susceptibility breakpoints. The frequency of these categorizations for individual drugs was determined. Results: Seven hundred five isolates were recovered from urine during the study period. Pathogens isolated most frequently were Escherichia coli, Klebsiella spp, and Proteus spp. Of 431 isolates retained in the data set, 412 (95.6%) were susceptible to cefdinir. This rate was comparable or superior to rates observed for other antibiotics: 49.4% for ampicillin, 84.9% for trimethoprim–sulfamethoxazole, 88.4% for cefazolin, 93.3% for nitrofurantoin, 94.2% for ticarcillin–clavulanate potassium, 97.5% for gentamicin, and 97.7% for ceftriaxone. Cefdinir, however, had lower activity (64.7%) against 17 bacterial isolates categorized as opportunistic or nosocomial pathogens. Conclusions: Cefdinir provides good coverage against common pathogens responsible for urinary tract infections in children and compares favorably with other oral and parenteral antibiotics that are used in the empiric treatment of this infection.     

Comparative activity of meropenem in US medical centers (2007): initiating the 2nd decade of MYSTIC program surveillance

Since 1997, the Meropenem Yearly Susceptibility Test Information Collection (MYSTIC) Program has monitored the antimicrobial activity of broad-spectrum agents against pathogens from hospitalized patients. In the United States, 2894 isolates were submitted in 2007 from 15 sites, including 1392 Enterobacteriaceae, 643 nonfermentative Gram-negative bacilli, and 829 Gram-positive cocci. All isolates were tested by broth microdilution methods. Meropenem (MIC(90) range, 0.12-2 microg/mL) exhibited the lowest resistance rates (1.9-2.4%) against Enterobacteriaceae, and fluoroquinolones had the highest rates of resistance (17.3-18.3%). KPC carbapenemases, usually found in Klebsiella pneumoniae, were also detected in Citrobacter freundii, Enterobacter spp., and Escherichia coli. Confirmed extended-spectrum beta-lactamase-producing isolate rates for E. coli, Klebsiella spp., and Proteus mirabilis isolates were 6.0%, 12.0%, and 0.0%, respectively. Meropenem remained active against Gram-positive pathogens such as staphylococci (methicillin-susceptible; MIC(90), 0.12-0.25 microg/mL), Streptococcus pneumoniae (MIC(90), 0.5 microg/mL), and beta-hemolytic and viridans group streptococci (MIC(90) range, 0.06-0.25 microg/mL). These US MYSTIC Program results demonstrate the continued emergence of novel beta-lactamases and multidrug-resistant bacterial phenotypes necessitating monitoring of carbapenem activities against Enterobacteriaceae species as well as nonfermentative bacilli.     

Antimicrobial resistance among uropathogens that cause community-acquired urinary tract infections in Antananarivo, Madagascar

BACKGROUND: Urinary tract pathogens obtained from patients in Madagascar are becoming increasingly resistant to commonly used antibiotics that are readily available at a low price. This poses a real problem for the treatment of community-acquired urinary tract infections (UTIs) in Madagascar. OBJECTIVES: To obtain data on the pathogens responsible for community-acquired UTIs in Antananarivo and on their susceptibility patterns to the antimicrobial agents that are currently used to treat UTIs. METHODS: We conducted a retrospective study on bacteria isolated from the urine of patients at the Institut Pasteur of Madagascar between January 2004 and April 2006. RESULTS: We isolated 903 pathogens from 673 women and 213 men. The most commonly isolated bacteria were Escherichia coli (607 strains), Klebsiella pneumoniae (87 strains), Staphylococcus aureus (35 strains) and Proteus mirabilis (32 strains). Seventy-seven per cent of Gram-negative bacilli were resistant to amoxicillin, 65.7% were resistant to trimethoprim/sulfamethoxazole and more than 15% were resistant to ciprofloxacin. Strains were rarely resistant to more expensive antibiotics (ceftriaxone 5.9%, fosfomycin 4.6%). Most bacteria showed intermediate susceptibility to nitroxolin. Resistance rates of E. coli to ceftriaxone and gentamicin increased significantly between 2005 and 2006, due to the increase in strains harbouring an extended-spectrum beta-lactamase. Gram-positive bacteria, Streptococcaceae and Staphylococcus spp. were rarely resistant, but 9.5% of streptococci were resistant to penicillin A and 8% of staphylococci were resistant to oxacillin. CONCLUSIONS: The rate of amoxicillin- and trimethoprim/sulfamethoxazole-resistant Enterobacteriaceae implies that another antibiotic should be used for empirical treatment and that there is a need for new generic drugs in developing countries, especially in Madagascar.     

Species and antimicrobial resistance of uropathogens isolated from patients with urinary catheter

A large number of hospitalized patients have an indwelling urinary tract catheter (IUC) placed at some time during their hospital stay and may suffer from catheter-associated urinary tract infections, the leading cause of nosocomial infections. Here we investigated the prevalence of uropathogens associated with catheter-associated urinary tract infections and assessed the resistances of these pathogens to commonly prescribed antibiotics. In total, 2,997 urine samples were examined at a regional hospital in Taipei, Taiwan in 2004: 1,948 (65%) samples from hospitalized patients and 1,049 (35%) samples from outpatients. Patients with IUCs accounted for 1,381 samples (46%). Stratified analyses were used to calculate the age- and gender-adjusted odds ratio (OR) of antimicrobial resistance associated with the use of IUCs. Compared to the urine specimens of the patients without IUCs, those isolated from catheterized patients had a lower prevalence rate of Escherichia (E.) coli (23.4% vs 36.8%) and higher rates of resistant strains including Pseudomonas species (16.4% vs 8.6%) and rare gram-negative bacilli (5.8% vs 4.5%). Additionally, IUCs significantly increased the antimicrobial resistance of E. coli (OR 2.41-3.07), other species of Enterobacteriaceae (OR 1.57-2.38), and rare gram-negative bacilli (OR 2.41-5.21) to nearly all antibiotics tested, such as trimethoprim/sulfamethoxazole. Thus, IUCs increased the prevalence of urinary tract infections caused by some highly resistant pathogens. Moreover, IUCs were associated with the increased risk of concurrent resistance of Enterobacteriaceae. Clinicians are advised to exercise better management of urinary catheter in order to further reduce and control catheter-associated urinary tract infections in hospitals.