An international survey of the antimicrobial susceptibility of pathogens from uncomplicated urinary tract infections: the ECO.SENS Project

The ECO.SENS study is the first international survey to investigate the prevalence and susceptibility of pathogens causing community-acquired acute uncomplicated urinary tract infections (UTIs). Midstream urine samples were taken for culture and for testing for the presence of leucocytes from 4734 women not older than 65 years presenting with symptoms of acute UTI at 252 community health care centres in 17 countries. Recognized urinary tract pathogens were identified and the susceptibility to 12 antimicrobials determined. Pathogens were present in 3278 (69.2%) patients, Escherichia coli accounting for 77.0% of isolates. In E. coli, 42% of the isolates were resistant to one or more of the 12 antimicrobial drugs investigated. Resistance was most common to ampicillin (29.8%) and sulfamethoxazole (29.1%), followed by trimethoprim (14.8%), trimethoprim/sulfamethoxazole (14.1%) and nalidixic acid (5.4%). Resistance in E. coli to co-amoxiclav, mecillinam, cefadroxil, nitrofurantoin, fosfomycin, gentamicin and ciprofloxacin was <3%. However, co-amoxiclav resistance was apparent in Portugal (9.3%) as was resistance to the quinolones, nalidixic acid and ciprofloxacin, in Portugal (11.6% and 5.8%, respectively) and Spain (26.7% and 14.7%, respectively). Overall, Proteus mirabilis were less resistant to ampicillin (16.1%) and more resistant to trimethoprim (25.5%) than E. coli, whereas Klebsiella spp. were more resistant to ampicillin (83.5%) and fosfomycin (56.7%). 'Other Enterobacteriaceae' were more resistant to the broad spectrum beta-lactams (ampicillin 45.9%, co-amoxiclav 21.3% and cefadroxil 24.6%), nitrofurantoin (40.2%) and fosfomycin (15.6%). In Staphylococcus saprophyticus resistance development was rare. Overall, antimicrobial resistance was lowest in the Nordic countries and Austria and highest in Portugal and Spain.     

Urinary tract infection trends in Latin American hospitals: report from the SENTRY antimicrobial surveillance program (1997-2000)

Urinary tract infections (UTI) are one of the most common infectious diseases diagnosed in outpatients as well as in hospitalized patients. The objective of this study was to report the frequency of occurrence and antimicrobial susceptibility of uropathogens collected in Latin America between 1997 to 2000 through the SENTRY Antimicrobial Surveillance Program. Antimicrobial susceptibility testing was performed and results interpreted using reference broth microdilution methods. In the 4 year period, a total of 1961 urine isolates from hospitalized patients were included. The patients' mean age was 51.3 years and most of the infections occurred among women (65.6%). Esherichia coli was the most frequent pathogen isolated followed by Klebsiella spp., Pseudomonas aeruginosa, and Proteus mirabilis. Among the E. coli isolates, piperacillin/tazobactam, aztreonam, extended-spectrum cephalosporins, carbapenems and amikacin constitute reasonable therapeutic options for treatment of serious UTI in Latin America (91.0-100.0% susceptible). High resistance rates to fluoroquinolones (17.5-18.9%) and trimethoprim/sulfamethoxazole (>45.0%) were observed among the E. coli. In contrast, nitrofurantoin displayed susceptibility rate of > 87.0%. Against Klebsiella spp. infections, the only effective therapeutic option would be the carbapenems due to the high number of isolates (>30.0%) producing extended-spectrum beta-lactamases (ESBL). Even the new fluoroquinolones showed limited activity against Klebsiella spp. (72.1-88.6% susceptible) and the P. aeruginosa isolates showed high resistance rates to most antimicrobial agents tested. The results of this survey endorse the importance of Enterobacteriaceae as cause of UTI in Latin America. Our results also demonstrate that the uropathogens isolated in the Latin American medical centers exhibit high resistance to various classes of antimicrobial agents. Carbapenem-resistant P. aeruginosa, ciprofloxacin-resistant E. coli, ESBL-producing K. pneumoniae constitute serious problem in this geographic region.     

Antibiotic susceptibility of bacterial strains isolated from urinary tract infections in Poland

Worldwide data show that there is increasing resistance among urinary tract pathogens to conventional drugs. The aim of this study was to obtain data on susceptibility patterns of pathogens responsible for urinary tract infections (UTIs) in Poland to currently used antimicrobial agents. A multicentre study of 141 pathogens from hospital-acquired infections and 460 pathogens from community-acquired infections was carried out between July 1998 and May 1999. The most prevalent aetiological agent was Escherichia coli (73.0%), followed by Proteus spp. (8.9%) and other species of Enterobacteriaceae (9.6%). Few community infections were caused by Gram-positive bacteria (2.2%). Gram-positive cocci were isolated more frequently from a hospital setting (14.1%) and the most common were Enterococcus spp. (8.5%). Pseudomonas aeruginosa was found only among hospital isolates and was responsible for 10.7% of infections. E. coli isolates from both community and hospital infections were highly susceptible to many antimicrobial agents with the exception of those isolates producing extended-spectrum beta-lactamases (ESBLs). Of all Enterobacteriaceae tested, 38 strains (6.9%) were capable of producing ESBLs.     

Characteristics of pathogens causing urinary tract infections in hospitals in North America: results from the SENTRY Antimicrobial Surveillance Program, 1997.

Urinary tract infection (UTI) is common and involves pathogens with changing susceptibility patterns. The SENTRY Antimicrobial Surveillance Program evaluates international pathogen incidence patterns to detect and manage the emergence of resistant strains. We describe the antimicrobial resistance patterns among 1617 pathogens recovered from UTIs during the third-quarter of 1997 in North America (United States and Canada), as part of this worldwide program. The isolates were tested against more than 50 antimicrobial agents (20 reported) by reference broth microdilution methods, and selected isolates were characterized by pulsed-field gel electrophoresis (PFGE) and automated ribotyping. The five most frequently isolated species were Escherichia coli (48.6%), Enterococcus spp. (13.7%), Klebsiella spp. (12.0%), Pseudomonas aeruginosa (6.2%), and Enterobacter spp. or Proteus mirabilis (3.8% each). For each nation, imipenem and cefepime produced the widest spectrum of coverage among the beta-lactams and amikacin was best among the aminoglycosides. For Gram-negative species, high resistance among beta-lactam antimicrobial agents was noted especially for various penicillins against E. coli (37.9% to 42.8%) and for the cephalosporins tested against enterococci (99.4% and 100%). Approximately 7.0% of enterococci in the USA were vancomycin-resistant (88% with Van A). P. aeruginosa provided the most consistent levels of resistance, but the following agents were most active against these organisms: amikacin (96.6 to 97.4% susceptible), tobramycin (89.5 to 100.0%), piperacillin/tazobactam (89.5 to 100.0%), piperacillin (89.5 to 96.6%), imipenem (89.7 to 92.1%), cefepime (77.6 to 89.7%), and ceftazidime (82.9 to 86.2%). E. coli (2.2 to 2.7%), K. pneumoniae (6.2 to 6.4%), and a single Enterobacter cloacae strain produced extended-spectrum beta-lactamases; and five other Enterobacter spp. were likely to have expressed chromosomally mediated (Amp C) Stably derepressed cephalosporinases with associated resistance to ceftazidime (16.7 to 21.2% resistance). These data demonstrated that several UTI isolates in SENTRY hospitals have high levels of resistance to various classes of antimicrobial agents with little evidence of clonal dissemination.     

Epidemiology and frequency of resistance among pathogens causing urinary tract infections in 1,510 hospitalized patients: a report from the SENTRY Antimicrobial Surveillance Program (North America)

Bacterial urinary tract infections (UTIs) are an important cause of septicemia resulting in high mortality rates, prolonged hospital stays and increased healthcare costs. Periodic reviews of pathogen frequency and susceptibility patterns impact on appropriate antimicrobial usage, leading to more effective prescribing practices. As part of the SENTRY Antimicrobial Surveillance Program (SENTRY, 1998), participants collected 50 consecutive UTI pathogens from patients hospitalized in 31 medical centers (26 in the United States and five in Canada) and forwarded subcultures to the coordinating center. Thirty-four antimicrobial agents were tested including two investigational compounds (quinupristin/dalfopristin [Q/D], gatifloxacin). The rank order of the 32 species identified during the study was: Escherichia coli (46.9%) > Enterococcus spp. (12.8%) > Klebsiella spp. (11.0%) > Pseudomonas aeruginosa (7.5%) > Proteus mirabilis (5.0%) > coagulase-negative staphylococci (CoNS; 3.4%). This pathogen rank order did not change from 1997 to 1998, but resistance patterns changed. Clonal spread of confirmed extended spectrum beta-lactamase-producing strains was not observed, but co-resistance was elevated for aminoglycosides, tetracyclines, sulfonamides, and fluoroquinolones. P. aeruginosa was most susceptible to amikacin (97.3%) > piperacillin +/- tazobactam (92.0-95.6%) > cefepime = imipenem (91.2%) > ceftazidime (85.8%). Fluoroquinolone resistance was greater in P. aeruginosa (24.8-39.8%) > P. mirabilis (5.3-13.3%) > Enterobacter spp. (6.7-8.9%) > Klebsiella spp. (4.2-7.8%) > E. coli (3.0-3.8%). Only 5% of enterococci were resistant to vancomycin. These results emphasize the need for continued surveillance studies for common infections which establish baseline resistance patterns by geographic areas, and have the potential to detect epidemics or direct local epidemiologic interventions.     

Epidemiology of urinary tract infections: incidence,morbidity, and economic costs

Urinary tract infections (UTIs) are considered to be the most common bacterial infection. According to the 1997 National Ambulatory Medical Care Survey and National Hospital Ambulatory Medical Care Survey, UTI accounted for nearly 7 million office visits and 1 million emergency department visits, resulting in 100,000 hospitalizations. Nevertheless, it is difficult to accurately assess the incidence of UTIs, because they are not reportable diseases in the United States. This situation is further complicated by the fact that accurate diagnosis depends on both the presence of symptoms and a positive urine culture, although in most outpatient settings this diagnosis is made without the benefit of culture.Women are significantly more likely to experience UTI than men. Nearly 1 in 3 women will have had at least 1 episode of UTI requiring antimicrobial therapy by the age of 24 years. Almost half of all women will experience 1 UTI during their lifetime. Specific subpopulations at increased risk of UTI include infants, pregnant women, the elderly, patients with spinal cord injuries and/or catheters, patients with diabetes or multiple sclerosis, patients with acquired immunodeficiency disease syndrome/human immunodeficiency virus, and patients with underlying urologic abnormalities. Catheter-associated UTI is the most common nosocomial infection, accounting for >1 million cases in hospitals and nursing homes. The risk of UTI increases with increasing duration of catheterization. In noninstitutionalized elderly populations, UTIs are the second most common form of infection, accounting for nearly 25% of all infections.There are important medical and financial implications associated with UTIs. In the nonobstructed, nonpregnant female adult, acute uncomplicated UTI is believed to be a benign illness with no long-term medical consequences. However, UTI elevates the risk of pyelonephritis, premature delivery, and fetal mortality among pregnant women, and is associated with impaired renal function and end-stage renal disease among pediatric patients. Financially, the estimated annual cost of community-acquired UTI is significant, at approximately $1.6 billion.     

Urinary tract infections,antibiotic resistance and sales of antimicrobial drugs: An observational study of uncomplicated urinary tract infections in Icelandic women

Objectives - To analyse the antimicrobial susceptibility pattern of bacteria causing symptomatic but otherwise uncomplicated lower urinary tract infections (UTI) in primary health care and the sales of antimicrobial drugs. Setting - Primary health care in Akureyri District, Northern Iceland, with about 17,400 inhabitants. Patients - A total of 516 episodes of symptomatic but otherwise uncomplicated lower UTI in women 10 to 69 years of age. Main outcome measures - Number of verified UTI, bacterial species, antimicrobial susceptibility pattern, and total sales of antimicrobial drugs. Results - Escherichia coli was by far the most common cause of UTI (83%), followed by Staphylococcus saprophyticus (7%). Infections caused by E. coli resistant to ampicillin accounted for 36% of cases, with the corresponding figures for sulfafurazol being 37%, cephalothin 45%, trimethoprim 13% and mecillinam 14%. Only 1% of the strains were resistant to nitrofurantoin. The total use of antimicrobial drugs was 17.4 DDD/1000 inhabitants/day. Conclusions - The resistance of bacteria causing uncomplicated UTI to common antimicrobials is high and must be taken into account when selecting treatment strategies. High consumption of antibiotics in the community indicates possible association.     

Urinary tract infections, antibiotic resistance and sales of antimicrobial drugs--an observational study of uncomplicated urinary tract infections in Icelandic women

OBJECTIVES: To analyse the antimicrobial susceptibility pattern of bacteria causing symptomatic but otherwise uncomplicated lower urinary tract infections (UTI) in primary health care and the sales of antimicrobial drugs. SETTING: Primary health care in Akureyri District, Northern Iceland, with about 17400 inhabitants. PATIENTS: A total of 516 episodes of symptomatic but otherwise uncomplicated lower UTI in women 10 to 69 years of age. MAIN OUTCOME MEASURES: Number of verified UTI, bacterial species, antimicrobial susceptibility pattern, and total sales of antimicrobial drugs. RESULTS: Escherichia coli was by far the most common cause of UTI (83%), followed by Staphylococcus saprophyticus (7%). Infections caused by E. coli resistant to ampicillin accounted for 36% of cases, with the corresponding figures for sulfafurazol being 37%, cephalothin 45%, trimethoprim 13% and mecillinam 14%. Only 1% of the strains were resistant to nitrofurantoin. The total use of antimicrobial drugs was 17.4 DDD/1000 inhabitants/day. CONCLUSIONS: The resistance of bacteria causing uncomplicated UTI to common antimicrobials is high and must be taken into account when selecting treatment strategies. High consumption of antibiotics in the community indicates possible association.     

Susceptibility patterns of orally administered antimicrobials among urinary tract infection pathogens from hospitalized patients in North America: comparison report to Europe and Latin America. Results from the SENTRY Antimicrobial Surveillance Program (2000)

Urinary tract infections (UTIs) remain a worldwide nosocomial infection problem. Geographic variations in pathogen occurrence and susceptibility profiles require monitoring to provide information to guide new (garenoxacin [BMS284756]) therapeutic options. Two thousand seven hundred-eighty UTI isolates from Europe (n = 783), Latin America (531), and North America (1,466) were tested and compared against 44 agents by reference methods in the SENTRY Antimicrobial Surveillance Program. The top seven pathogens accounted for 90% of all isolates and the rank order for all regions was: Escherichia coli (1,316; 47%), Enterococcus spp. (351; 13%), Klebsiella spp. (306; 11%), Pseudomonas aeruginosa (210; 8%), Proteus mirabilis (145; 5%), Enterobacter spp. (97; 4%), and Citrobacter spp. (78; 3%). The pathogen rank order was similar among regions except for the rarer occurrence of Enterococcus spp. (Rank #6, 4%) in Latin America. E. coli ampicillin resistance was highest in Europe and Latin America (51-55%). Ampicillin (37%), ciprofloxacin or garenoxacin (4%), and trimethoprim/sulfamethoxazole (23%) resistance remained lowest in North America. Nitrofurantoin susceptibility in E. coli was still at acceptable levels and ranged from 91 to 96% across regions. The regional ciprofloxacin-resistant rank order for P. aeruginosa by region was: Latin America (55%) > Europe (41%) > North America (29%). Vancomycin-resistant enterococci (VRE) were only detected in North America (7%). Garenoxacin possessed a 34 to 44% wider spectrum compared to ciprofloxacin against enterococci UTI isolates. Extended spectrum beta-lactamase rates for E. coli and Klebsiella spp. were 4 and 19%, respectively. These results emphasized the need to assess the often striking differences in pathogen occurrence and resistance rates among the commonly encountered UTI pathogens.     

Risk factors for ciprofloxacin resistance among Escherichia coli strains isolated from community-acquired urinary tract infections in Turkey

OBJECTIVES: To determine the risk factors for community-acquired ciprofloxacin-resistant Escherichia coli urinary tract infection (UTI). METHODS: The study was performed with isolates from community-acquired UTIs collected from 15 centres representing six different geographic regions of Turkey. All microbiological procedures were carried out in a central laboratory. Multivariate analysis was performed for detection of risk factors for resistance. Use of quinolones more than once within the last year, living in a rural area, having a urinary catheter, age >50 and complicated infections were included in the model as variables and logistic regression was performed. RESULTS: A total of 611 gram-negative isolates were studied: 321 were isolated from uncomplicated UTI and 290 were isolated from complicated UTI. E. coli was the causative agent in 90% of the uncomplicated UTIs and in 78% of the complicated UTIs (P < 0.001). Seventeen percent of E. coli strains isolated from uncomplicated cases and 38% of E. coli strains isolated from complicated UTI were found to be resistant to ciprofloxacin. In multivariate analysis, age over 50 [odds ratio (OR): 1.6; confidence interval (CI): 1.08-2.47; P = 0.020], ciprofloxacin use more than once in the last year (OR: 2.8; CI: 1.38-5.47; P = 0.004) and the presence of complicated UTI (OR: 2.4; CI: 1.54-3.61; P < 0.001) were found to be associated with ciprofloxacin resistance. Detection of strains of E. coli producing extended-spectrum beta-lactamase (ESBL) enzymes was two times more common in the patients who received ciprofloxacin than those who did not (15% versus 7.4%). CONCLUSIONS: The increasing prevalence of infections caused by antibiotic-resistant bacteria makes the empirical treatment of UTIs more difficult. One of the important factors contributing to these high resistance rates might be high antibiotic use. Urine culture and antimicrobial susceptibility testing are essential in Turkey for patients with UTI who have risk factors for resistance, such as previous ciprofloxacin use. Fluoroquinolone-sparing agents such as nitrofurantoin and fosfomycin should be evaluated as alternative therapies by further clinical efficacy and safety studies.     

187例医院内尿路感染病原分布和抗生素耐药分析

目的 :了解医院内尿路感染的病原分布和对抗生素的耐药情况及其比较与院外尿路感染的差别 ,企图以此指导临床用药。方法 :收集 187例医院内尿路感染和同期住院的 14 5例院外尿路感染进行比较。结果 :医院内尿路感染的优势菌依次为 :大肠埃希菌 2 8.2 4 % ,肠球菌 2 1.37% ,念珠菌 14 .89% ,克雷伯杆菌 8.0 2 % ,假单胞菌 7.2 5 %和链球菌 4 .96 %。其中医院内念珠菌的感染率较院外显著升高 (P <0 .0 1)。有尿路操作者中大肠埃希菌 33.33% ,肠球菌 16 .92 % ,念珠菌 16 .4 1%和假单胞菌8.2 1%。其中念珠菌和假单胞菌的感染率显著高于无尿路操作者 (P <0 .0 5 ,P <0 .0 1)。在院内感染者中 ,大肠埃希菌对环丙沙星和头孢哌酮的耐药性 ,肠球菌对青霉素的耐药性药明显高于院外感染者 (P <0 .0 5 ,P <0 .0 5 ,P <0 .0 5 )。结论 :院内尿路感染中有较多尿路操作和广谱抗生素的使用史 ,念珠菌的感染率明显升高 ,细菌对抗生素耐药的情况较多 ,应注意调整治疗方案。     

Urinary tract infection: traditional pharmacologic therapies

Urinary tract infections (UTIs) are common bacterial infections, particularly in women. Antimicrobial therapy is seldom indicated for asymptomatic infection, but antimicrobial therapy is usually indicated for amelioration of symptoms. Management of acute uncomplicated UTI (cystitis) is generally straightforward, with a predictable distribution of uropathogens isolated. First-line treatment of acute uncomplicated UTI has traditionally involved a 3-day regimen of trimethoprim-sulfamethoxazole (TMP-SMX) or TMP alone for patients with sulfa allergies. Increasing resistance among community-acquired Escherichia coli to TMP-SMX worldwide has led to a reassessment of the most appropriate empiric therapy for these infections. Alternative first-line agents include the fluoroquinolones, nitrofurantoin, and fosfomycin.Factors to be considered in the selection of appropriate antimicrobial therapy include pharmacokinetics, spectrum of activity of the antimicrobial agent, resistance prevalence for the community, potential for adverse effects, and duration of therapy. Ideal antimicrobial agents for UTI management have primary excretion routes through the urinary tract to achieve high urinary drug levels. In addition, there are special considerations in the management of UTI among selected populations, including postmenopausal and pregnant women, and for women with frequent recurrent UTIs.     

儿科院内感染细菌分布及耐药性监测

目的:了解儿科院内感染常见细菌分布并监测其耐药性.方法:收集惠儿标本,进行常规细菌培养及K-B法药敏试验.结果:分离出238株痛原菌,以克雷伯菌属为最多123株(51.7%).其次为凝固酶阴性葡萄球菌(coagulase negative staphylococci,CNS)50株(21.0%);123株克雷伯菌属中产ESBLs的菌株96株(78.0%);19株大肠埃希菌中产ESBLs的菌株12株(63.2%).产ESBLs克雷伯菌属和大肠埃希菌对抗菌药物的耐药率明显高于非产ESBLs的相应细菌.检出41株(80.2%)凝固酶阴性耐甲氧西林葡萄球菌(meahicillin resistant coagulase negative staphylococci,MRCNS),未检出耐甲氧西林的金黄色葡萄球菌(meahicillin resistant staphylococcus aureus,MRSA).凝固酶阴性葡萄球菌和金黄色葡萄球菌对青霉素全部耐药.结论:儿科的院内感染革兰阴性茵以克雷伯菌属最多见,革兰阳性菌以凝固酶阴性葡萄球菌居多,两类痛原菌多重耐药现象比较严重.     

Norfloxacin in the treatment of urinary tract infections

28 patients with urinary tract infections (UTI) were treated with norfloxacin 2 X 400 mg daily for 9 days. 14 of these patients had complicated UTI (stones, obstruction). The main pathogens were E. coli and Proteus mirabilis. On the third day of treatment all bacteria were eradicated. One week after therapy all patients with uncomplicated UTI were cured and, likewise, 9 of 14 with complicated UTI. There was no laboratory evidence of adverse effects. 6 patients reported only mild side effects such as epigastric pain, dizziness and pruritus, which did not necessitate discontinuation of norfloxacin. Norfloxacin appears to be safe and effective in the treatment of UTI.     

Antimicrobial activity of tigecycline tested against organisms causing community-acquired respiratory tract infection and nosocomial pneumonia

Emerging antimicrobial resistance among respiratory tract pathogens has created a critical need for development of new antimicrobial agents that are not affected by the commonly occurring genetic resistance mechanisms. Tigecycline, a novel broad-spectrum parenteral glycylcycline, has been shown to be active against many of Gram-positive, Gram-negative, atypical, and anaerobic organisms, including strains highly resistant to commonly prescribed antimicrobials and was recently approved by the US Food and Drug Administration for treating infections of skin and skin structures, and for intra-abdominal infections. In this study, tigecycline spectrum and potency were evaluated against a global collection of pathogens (2000-2004) recovered from community-acquired respiratory infections (7580 strains) or from hospitalized patients with pneumonia (3183 strains). Among community-acquired infections, the ranking pathogens were Haemophilus influenzae (52.9%; 21% ampicillin-resistant), Streptococcus pneumoniae (39.2%; 23.7% penicillin-nonsusceptible), and Moraxella catarrhalis (7.9%). Tigecycline displayed potent activity by inhibiting 100% of the 3 species at clinically achievable concentrations (2, 1, and 0.5 microg/mL, respectively). The 10 most prevalent pathogens producing 94.3% of pneumonias in hospitalized patients were Staphylococcus aureus (48.5% of strains; 49.4% oxacillin-resistant), Pseudomonas aeruginosa (15.6%), Klebsiella spp. (5.6%), S. pneumoniae (4.6%), Acinetobacter spp. (4.5%), Enterobacter spp. (4.0%), Escherichia coli (3.8%), Serratia marcescens (2.5%), Enterococcus spp. (2.3%), Stenotrophomonas maltophilia (1.8%), and beta-hemolytic streptococci (1.1%). At a concentration of 4 microg/mL, tigecycline inhibited >96% of these pathogens (exception, P. aeruginosa). S. aureus was readily inhibited by tigecycline (MIC50 and MIC90, 0.25 and 0.5 microg/mL, respectively) with all strains inhibited at < or =1 microg/mL. Streptococci recovered from hospitalized patients (beta-hemolytic and S. pneumoniae) were also very susceptible to tigecycline with the highest MIC being 0.12 microg/mL. All E. coli (including 13.3% with an extended-spectrum beta-lactamase [ESBL] phenotype) were inhibited by < or =1 microg/mL, and all Klebsiella (25.8% ESBL phenotype) and Enterobacter spp. plus 97.0% of Serratia spp. were inhibited by < or =4 microg/mL. Tigecycline was also active against Acinetobacter spp. and S. maltophilia strains (MIC50 and MIC90, 1 and 4 microg/mL, respectively). Further clinical studies should consider the role that tigecycline may play in the therapy for severe respiratory tract infections, both of nosocomial and community origin.     

Antimicrobial activity of seven oral antibiotics against selected community- and hospital-acquired pathogens

The in vitro activity of seven oral antibiotics (ciprofloxacin, cephalexin, cefaclor, cefadroxil, cefuroxime, cefixime, and amoxicillin/clavulanate) was tested against 355 hospital-acquired pathogens and 342 community-acquired organisms. Whereas Staphylococcus aureus and Escherichia coli were the most common pathogens isolated in community-acquired infections, Enterobacter, Klebsiella, and Pseudomonas were isolated most frequently in hospital-acquired infections. All antibiotics with the exception of cefixime were active against the methicillin-susceptible staphylococci. Ciprofloxacin was the most active antibiotic against the members of the family Enterobacteriaceae and Pseudomonas. The community-acquired organisms tended to be more susceptible to antibiotics than the hospital-acquired organisms. Thus selection of oral antibiotics for the management of patients with hospital-acquired infections should be based on knowledge of the susceptibility patterns of hospital isolates.     

Occurrence and antimicrobial resistance pattern comparisons among bloodstream infection isolates from the SENTRY Antimicrobial Surveillance Program (1997-2002)

The empiric treatment of patients with bloodstream infections (BSI) has become more complicated in an era of increasing antimicrobial resistance. The SENTRY Antimicrobial Surveillance Program has monitored BSI from patients in medical centers worldwide since 1997. During 1997-2002, a total of 81,213 BSI pathogens from North America, Latin America, and Europe were tested for antimicrobial susceptibility. S. aureus, E. coli, and coagulase-negative staphylococci were the three most common BSI pathogens in all three regions each year. Prevalence variability was noted in regions for some species, including higher rates of isolation of E. coli in Europe, Enterococcus spp. in North America, and Gram-negative enteric and nonenteric species in Latin America. Patient age analysis showed the most common BSI pathogen among neonates was coagulase-negative staphylococci and among elderly patients, E. coli. Resistance among BSI pathogens was much more prevalent in nosocomial infections and in patients in intensive care units (ICUs); age differences were also noted. Geographically, oxacillin-resistant S. aureus (39.1%, 2002) and vancomycin-resistant enterococci (17.7%, 2002) were highest in North America, and extended-spectrum beta-lactamase-producing Klebsiella spp. (35.8-46.7%) and multidrug-resistant P. aeruginosa (18.7%, 2002) were highest in Latin America. Activity of commonly used antimicrobial agents remained relatively stable in North America, except in the case of vancomycin-resistant enterococci (20% decline between 1997 and 2002). An epidemiologic investigation of oxacillin-resistant S. aureus in North America identified 10 significant clones (ribotypes) and the common resistance patterns associated with them. Surveillance of BSI pathogens is needed to determine trends of resistance and provide useful information regarding patient risk factors and geographic differences.     

Potency and spectrum of tigecycline tested against an international collection of bacterial pathogens associated with skin and soft tissue infections (2000-2004)

The antimicrobial activity of tigecycline, a novel glycylcycline, was evaluated against 5289 bacterial isolates recovered from hospitalized patients with skin and soft tissue infections during 2000-2004. Strains were submitted from >70 medical centers in North America, Latin America, and Europe, and were tested centrally using reference broth microdilution methods. The top 10 ranking pathogens (95% of total) recovered included Staphylococcus aureus (55.2%), Enterococcus spp. (9.6%), Pseudomonas aeruginosa (6.4%), Escherichia coli (5.6%), beta-hemolytic streptococci (5.0%), coagulase-negative staphylococci (4.9%), Enterobacter spp. (2.8%), Klebsiella spp. (2.6%), Proteus mirabilis (1.7%), and indole-positive Proteae (1.2%). All staphylococci (S. aureus and coagulase-negative staphylococci), enterococci, beta-hemolytic streptococci, viridans group streptococci, and E. coli were inhibited by < or =2 microg/mL of tigecycline; in addition, 97% of Klebsiella spp., 95% of Enterobacter spp., and 97% of Acinetobacter spp. were inhibited at this concentration. Only P. aeruginosa and all Proteae (MIC90, 16 microg/mL) displayed elevated MIC values to tigecycline. The broad spectrum of activity exhibited by this glycylcycline included tetracycline-resistant organism subsets, as well as oxacillin-resistant S. aureus, vancomycin-resistant enterococci, and extended-spectrum beta-lactamase-producing enteric bacilli strains. Tigecycline represents a new choice among broad-spectrum parenteral agents for the common Gram-positive and -negative pathogens producing serious infections of skin and soft tissues.     

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.     

Antibiotic sensitivities of urinary pathogens, 1971-82

All urinary pathogens from general practice and from hospital have been tested for sensitivity to a range of antimicrobial drugs for the last 12 years. During that period there have been marked changes. In general practice there has been a marked increase in the proportion of staphylococcal infections, from 5.1% to 14.8%, and a noticeable decrease in the proportion caused by Proteus mirabilis, from 9.2% to 4.1%. Similar, but smaller, changes have been seen in the proportions of hospital UTI caused by those organisms, while the proportion of hospital infections due to Klebsiella-Enterobacter spp. has fallen from 16.8% to 8.3%. These, and other, changes have been reflected in changing antibiotic sensitivity patterns. In particular, sensitivity of urinary pathogens to ampicillin/amoxycillin and to cephaloridine has continued to fall both in general practice and in hospital. In general practice UTI nalidixic acid-resistance is becoming more important as the proportion of Gram-positive urinary pathogens increases. There has been little change in sensitivity to trimethoprim or co-trimoxazole over the last 12 years.