Susceptibility of bacterial isolates from Turkey--a report from the Meropenem Yearly Susceptibility Test Information Collection (MYSTIC) Program

The study monitored the susceptibility of nosocomial pathogens to meropenem and comparator antimicrobial agents isolated as part of the Meropenem Yearly Susceptibility Test Information Collection (MYSTIC) Program from Turkish university hospitals. In terms of minimum inhibitory concentration 90% (MIC(90)) values, meropenem was two- and eight-fold more active than imipenem against Escherichia coli and Klebsiella pneumoniae, respectively. 40.5% of K. pneumoniae, 23.1% of Klebsiella oxytoca and 15.3% of E. coli isolates were extended-spectrum beta-lactamase (ESBL) producers. Piperacillin/tazobactam was the most active agent against isolates of Pseudomonas aeruginosa, followed by meropenem and imipenem. Against Acinetobacter baumannii isolates, meropenem and imipenem were the most active agents. Continued surveillance by the MYSTIC Program appears to be prudent to help focus on effective empiric treatment regimens.     

Comparative antimicrobial potency of meropenem tested against Gram-negative bacilli: report from the MYSTIC surveillance program in the United States (2004)

The Meropenem Yearly Susceptibility Test Information Collection (MYSTIC) Program is a longitudinal resistance surveillance network of more than 100 medical centers worldwide monitoring the susceptibility of bacterial pathogens to carbapenems and other broad-spectrum agents. In 2004 (year six), the antimicrobial activity of 12 broad-spectrum agents was assessed against 2,799 Gram-negative bacterial isolates submitted from 15 United States (USA) medical centers using Clinical and Laboratory Standards Institute (CLSI; formerly NCCLS) recommended methods. Meropenem continued to demonstrate a high potency with MIC90 values 4- to 32-fold lower than imipenem against the Enterobacteriaceae. The wide spectrum of activity for meropenem against all Gram-negative isolates was demonstrated by the overall rank order of percentage susceptibility at CLSI breakpoints: amikacin (96.5%) > meropenem (96.0%) > imipenem (95.8%) > piperacillin/tazobactam (91.5%) > tobramycin (91.4%) > cefepime (91.2%) > ceftazidime (89.0%) > gentamicin (88.0%) > aztreonam (81.5%) > levofloxacin (80.5%) > ciprofloxacin (80.2%) > ceftriaxone (69.1%). Only the aminoglycosides (84.5%) and carbapenems (76.1-83.8%) exhibited acceptable levels of susceptibility against the Acinetobacter spp. isolates as this species group became more resistant to all antimicrobial classes. A continued increase in the resistance rate for both ciprofloxacin and levofloxacin over the six years was observed, most alarming among Escherichia coli (20.2-20.7%) and indole-positive Proteus species (34.4-42.2%) isolates, some documented as clonal. Continued surveillance of these broad-spectrum antimicrobial agents appears warranted to monitor the potency and spectrum of activity against Gram-negative pathogens causing serious infections and the emergence of new or novel resistance mechanisms that could compromise carbapenem therapy.     

Susceptibility of Bacterial Isolates From Turkey - A Report From the Meropenem Yearly Susceptibility Test Information Collection (MYSTIC) Program

Abstract

The study monitored the susceptibility of nosocomial pathogens to meropenem and comparator antimicrobial agents isolated as part of the Meropenem Yearly Susceptibility Test Information Collection (MYSTIC) Program from Turkish university hospitals. In terms of minimum inhibitory concentration 90% (MIC₉₀) values, meropenem was two- and eight-fold more active than imipenem against Escherichia coli and Klebsiella pneumoniae, respectively. 40.5% of K. pneumoniae, 23.1% of Klebsiella oxytoca and 15.3% of E. coli isolates were extended-spectrum β-lactamase (ESBL) producers. Piperacillin/tazobactam was the most active agent against isolates of Pseudomonas aeruginosa, followed by meropenem and imipenem. Against Acinetobacter baumannii isolates, meropenem and imipenem were the most active agents. Continued surveillance by the MYSTIC Program appears to be prudent to help focus on effective empiric treatment regimens.     

In Vitro Activity of Meropenem against Ciprofloxacin-Resistant Enterobacteriaceae and Pseudomonas aeruginosa

Abstract

The in-vitro susceptibilities of a total of 174 ciprofloxacin-resistant Enterobacteriaceae and Pseudomonas aeruginosa were determined. According to the BSAC and NCCLS breakpoints, meropenem, aztreonam, ceftibuten, ceftazidime, imipenem and cefotaxime were the most active (>90%) antimicrobial agents tested against Enterobacteriaceae. Susceptibility of these strains to piperacillin/tazobactam, cefpodoxime and cefixime (84.96%) was higher than that to tobramycin, gentamicin and fosfomycin (50-75%). More than 90% of P. aeruginosa were susceptible to meropenem when both interpretative susceptibility breakpoint criteria were used. Piperacillin, piperacillin/tazobactam and ceftazidime were active against 50-75% of the same strains. Meropenem was the most active antimicrobial tested against all ciprofloxacin-resistant clinical isolates assayed.     

Resistance surveillance in Italy: four-year results from the MYSTIC program

The MYSTIC program is an international, multicenter surveillance study that compares the activity of meropenem, in centers that are prescribers, with that of imipenem, ceftazidime, piperacillin/tazobactam, ciprofloxacin and gentamicin. These Italian data are from 3 centers (neutropenia, cystic fibrosis and intensive care units). A total of 2,072 (238 Gram-positive and 1,834 Gram-negative) aerobic microorganisms were collected during the study. Pseudomonas aeruginosa (33.4%) was the most isolated species followed by Escherichia coli (14.4%). All except one Enterobacteriaceae strain isolated were fully susceptible to meropenem. Moreover, the activity of meropenem against Enterobacteriaceae was about eight-fold greater than that of imipenem and four- to eight-fold more active than that of ceftazidime. Meropenem was highly active against non-fermentative Gram-negative microorganisms, exceeding the activity of most of the other antimicrobial agents tested. Moreover, meropenem showed increasing activity during the 4 years of study (starting from 86.2% in 1997 to 94.0% in 2000). In conclusion, our results indicate that meropenem has excellent potency and spectrum of activity despite being prescribed for the treatment of seriously ill patients, and appears to be a reliable option for the initial empirical treatment of serious nosocomial infections.     

Antimicrobial susceptibility patterns of clinical isolates of gram-negative bacteria obtained from intensive care units in a tertiary hospital in Beijing, China

In this study we investigated the prevalence of antimicrobial resistance in clinical isolates of Gram-negative bacteria obtained from intensive care units (ICUs) in the People's Liberation Army (PLA) 309 Hospital located in beijing, China. between 2007 and 2010, a total of 1949 isolates of Gram-negative bacteria were collected and tested using an antibiotic susceptibility assay. A marked decrease was observed in the susceptibility of Acinetobacter baumannii to imipenem and amikacin as compared to that described in a previous report in China. Similar results were obtained for Pseudomonas aeruginosa. However, imipenem and amikacin showed strong activity against Escherichia coli and Klebsiella pneumoniae. Overall, the high rates of antimicrobial resistance against ICU pathogens in our hospital indicated a critical condition in Beijing, China. Development of a national control and monitoring system by the government may be an ideal method to solve the present problem of managing infections due to Gram-negative bacterial pathogens.     

Emerging antimicrobial resistances among Proteus mirabilis in Europe: report from the MYSTIC Program (1997-2001). Meropenem Yearly Susceptibility Test Information Collection

Resistance patterns that are currently problematic in Europe can vary greatly within the same species over time, among various patient populations and among geographic regions on the same continent. The results from the Meropenem Yearly Susceptibility Test Information Collection (MYSTIC) Program, which monitors carbapenem resistance rates in institutions using meropenem, were used to determine resistance differences among Proteus mirabilis. MIC results from 688 P. mirabilis strains were classified into 4 patient care groups: ICU (n=426), neutropenia patients (NP; n=145), general wards (n=97) and cystic fibrosis patients (CF; n=20). A total of 40 centers from 12 European countries have participated since 1997, divided into 3 geographic regions (East, North, South). All testing was performed by NCCLS reference methods and interpretive criteria, including screening of extended-spectrum beta-lactamase (ESBL) phenotypes. Over the monitored interval the resistance rates varied for each agent without a clear trend toward a greater rate. Rank order of susceptibility was: meropenem (99%) > piperacillin/tazobactam (TAZ; 96%) > cefepime (95%) > ceftazidime (CAZ; 94%) > imipenem (IPM; 92%). Ciprofloxacin (CIP) was the least active agent tested (MIC90 4 microg/ml; 86% susceptible). Unexpectedly, 3.6% of P. mirabilis were imipenem-resistant (MIC, > or = 16 microg/ml). Greater rates of resistance were found for strains from NP and CF patients, and from eastern or southern European sites, usually associated with epidemic clusters. Generally susceptible species such as P. mirabilis have recently emerged as therapeutic problems in European medical centers following mutations that compromise CIP, CAZ and aminoglycoside use. Imipenem also showed decreased susceptibility of greater than 7% compared to less than 1% for meropenem. Continued surveillance by the MYSTIC Program appears to be a prudent practice to focus effective empiric treatment regimens.     

Monitoring of antibiotic resistance in bacterial isolates from bacteremic patients

The aim of the study was to monitor the prevalence of pathogens and development of resistance in bacteria isolated from bacteremic patients. Five University Clinics and/or Regional Hospitals in the Slovak Republic participated in the study and a total of 421 isolates were collected in the second half of the year 2002. The most prevalent organisms were coagulase-negative staphylococci (CONS) (19%), Staphylococcus aureus (18.3%), among Gram-negative bacteria Escherichia coli (13.3%), Klebsiella pneumoniae (11.4%) and Pseudomonas aeruginosa (7.8%) followed by enterococci, Acinetobacter baumannii and Enterobacter sp. All CONS and S. aureus were susceptible to vancomycin; resistance to oxacillin was observed for 55% of the CONS and only for 4% of S. aureus isolates. A higher prevalence of resistance to erythromycin, clindamycin, gentamicin and ofloxacin was found in CONS in comparison to S. aureus. Enterococcus sp. isolates were fully susceptible to vancomycin and teicoplanin. Gentamicin, amoxicillin/clavulanate, third generation cephalosporins and ciprofloxacin showed good activity against E. coli. Although 17% of K. pneumoniae isolates were resistant to ciprofloxacin, it was the most effective drug against K. pneumoniae; the prevalence of resistance to other antibiotics was rather higher. Gentamicin and ciprofloxacin were the most active against Enterobacter sp. isolates and ceftazidime and meropenem against P. aeruginosa.     

Emerging Antimicrobial Resistances Among Proteus mirabilis in Europe: Report from the MYSTIC Program (1997-2001)

Abstract

Resistance patterns that are currently problematic in Europe can vary greatly within the same species over time, among various patient populations and among geographic regions on the same continent. The results from the Meropenem Yearly Susceptibility Test Information Collection (MYSTIC) Program, which monitors carbapenem resistance rates in institutions using meropenem, were used to determine resistance differences among Proteus mirabilis. MIC results from 688 P. mirabilis strains were classified into 4 patient care groups: ICU (n=426), neutropenia patients (NP; n=145), general wards (n=97) and cystic fibrosis patients (CF; n=20). A total of 40 centers from 12 European countries have participated since 1997, divided into 3 geographic regions (East, North, South). All testing was performed by NCCLS reference methods and interpretive criteria, including screening of extended-spectrum β-lactamase (ESBL) phenotypes. Over the monitored interval the resistance rates varied for each agent without a clear trend toward a greater rate. Rank order of susceptibility was: meropenem (99%) > piperacillin/tazobactam (TAZ; 96%) > cefepime (95%) > ceftazidime (CAZ; 94%) > imipenem (IPM; 92%). Ciprofloxacin (CIP) was the least active agent tested (MIC₉₀, 4 μg/ml; 86% susceptible). Unexpectedly, 3.6% of P. mirabilis were imipenem-resistant (MIC, >16 μg/ml). Greater rates of resistance were found for strains from NP and CF patients, and from eastern or southern European sites, usually associated with epidemic clusters. Generally susceptible species such as P. mirabilis have recently emerged as therapeutic problems in European medical centers following mutations that compromise CIP, CAZ and aminoglycoside use. Imipenem also showed decreased susceptibility of greater than 7% compared to less than 1% for meropenem. Continued surveillance by the MYSTIC Program appears to be a prudent practice to focus effective empiric treatment regimens.     

Resistance patterns of Pseudomonas aeruginosa to carbapenems and piperacillin/tazobactam.

Pseudomonas aeruginosa is a major problem as a multiresistant nosocomial pathogen, especially in burns and other immunocompromised patients in our hospital. The present prospective study, conducted between June 1996 and December 1997, was aimed at determining the extent of its resistance against highly active antipseudomonal drugs, such as carbapenems (imipenem and meropenem) and ureidopenicillin with beta-lactamase inhibitor (piperacillin/tazobactam); existence of any cross resistance or difference in susceptibility between imipenem and meropenem; and to compare the activity of piperacillin/tazobactam with the two carbapenems against P. aeruginosa. Of the 357 P. aeruginosa isolates tested from 188 patients 37 (10.4%) were resistant to imipenem, 21 (5.9%) to meropenem and 50 (14%) to piperacillin/tazobactam. Cross resistance between the two carbapenems was observed in 5.9% of the isolates. Sixteen (43%) of the imipenem-resistant isolates were susceptible to meropenem but the reverse was observed in none. Amongst the 50 piperacillin/tazobactam-resistant isolates cross resistance with the two carbapenems was observed in 18 (36%) and in 9 (18%) only with imipenem; 23 (46%) were susceptible to both. Our results indicate that P. aeruginosa is least resistant to meropenem followed by imipenem and piperacillin/tazobactam. Cross resistance between the carbapenems and between carbapenems and piperacillin/tazobactam was found. The study further suggests that burns, cardiac-neuro-pediatric surgical, cancer and transplant patients are more susceptible to acquiring infection due to multiresistant P. aeruginosa than other types of patients and common infection sites were wounds, respiratory tract, urine, blood and intravascular lines.     

食管癌术后化疗患者肺部感染的病原菌分析及耐药性分析

目的分析食管癌术后化疗患者肺部感染病原菌的特点,并探讨病原菌耐药性,指导临床选择合理抗菌药物治疗食管癌化疗后肺部感染。方法选择182例食管癌术后化疗合并肺部感染的患者,分析病原菌分布情况及耐药性。结果182例患者共分离出病原菌236株,其中革兰阴性菌151株,革兰阳性菌56株,真菌29株。革兰阳性菌中金黄色葡萄球菌占比最高,其次为表皮葡萄球菌、肺炎链球菌;革兰阴性菌中铜绿假单胞菌占比最高,其次为鲍曼不动杆菌、肺炎克雷伯菌;真菌中以白色假丝酵母菌为主。革兰阳性菌及革兰阴性菌中主要病原菌均对多种常用抗菌药物存在不同程度耐药,金黄色葡萄球菌对头孢唑林、庆大霉素、红霉素及青霉素有较严重耐药(耐药率≥70.00%),对克林霉素及万古霉素有较低耐药(耐药率<30.00%);表皮葡萄球菌对头孢唑林、头孢曲松、庆大霉素、红霉素及青霉素有较严重耐药,对万古霉素不耐药;铜绿假单胞菌对头孢唑林及复方新诺明有较严重耐药,对亚胺培南、美罗培南、头孢呲肟、哌拉西林及阿米卡星有较低耐药;鲍曼不动杆菌对头孢唑林及氨曲南有较严重耐药,对亚胺培南及美罗培南有较低耐药。结论食管癌术后化疗合并肺部感染患者的病原菌主要为革兰阴性菌、革兰阳性菌、对多种抗菌药物存在不同程度的耐药性,应针对患者病原菌类型选择具有较低耐药性的抗菌药物,以避免抗菌药物滥用,提高肺部感染治疗效果。     

Resistance Surveillance in Italy: Four-Year Results from the MYSTIC Program

Abstract

The MYSTIC program is an international, multicenter surveillance study that compares the activity of meropenem, in centers that are prescribers, with that of imipenem, ceftazidime, piperacillin/tazobactam, ciprofloxacin and gentamicin. These Italian data are from 3 centers (neutropenia, cystic fibrosis and intensive care units). A total of 2,072 (238 Gram-positive and 1,834 Gramnegative) aerobic microorganisms were collected during the study. Pseudomonas aeruginosa (33.4%) was the most isolated species followed by Escherichia coli (14.4%). All except one Enterobacteriaceae strain isolated were fully susceptible to meropenem. Moreover, the activity of meropenem against Enterobacteriaceae was about eight-fold greater than that of imipenem and four- to eight-fold more active than that of ceftazidime. Meropenem was highly active against non-fermentative Gram-negative microorganisms, exceeding the activity of most of the other antimicrobial agents tested. Moreover, meropenem showed increasing activity during the 4 years of study (starting from 86.2% in 1997 to 94.0% in 2000). In conclusion, our results indicate that meropenem has excellent potency and spectrum of activity despite being prescribed for the treatment of seriously ill patients, and appears to be a reliable option for the initial empirical treatment of serious nosocomial infections.     

In vitro evaluation of ertapenem (MK-0826), a long-acting carbapenem, tested against selected resistant strains

Ertapenem (MK-0826) is a novel, long-acting parenteral carbapenem. The purpose of this in vitro study was to test ertapenem's activity against a collection of multiply-resistant strains of gram-positive and -negative bacteria isolated from locations worldwide, and to examine its bactericidal activity and ability to act in a synergistic manner in combination with other antimicrobial agents. Ertapenem was active against a variety of gram-negative pathogens, with particular potency noted for Escherichia coli and Klebsiella pneumoniae (MIC90s < or =0.015-0.5 microg/mL) including extended spectrum beta-lactamase producing strains. Less ertapenem activity was seen against Pseudomonas aeruginosa, especially ceftazidime-resistant strains (MIC50 16 microg/mL). Except for enterococci, ertapenem was active against most gram-positive species, including beta-haemolytic streptococci (MIC90 0.03 microg/mL; 100% susceptible), viridans group streptococci (MIC90 2 microg/mL; 98.1% susceptible), and penicillin-susceptible Streptococcus pneumoniae (MIC90 < or =0.015 microg/mL; 100% susceptible). Ertapenem was also very potent against Haemophilus influenzae (MIC90 0.25 microg/mL; 100% susceptible). Bactericidal action was observed versus staphylococci, E. coli, and K. pneumoniae, and at least an additive effect was detected against the majority of the strains tested when ertapenem was combined with ciprofloxacin or gentamicin. These results from testing 902 organisms indicate that ertapenem appears to be a promising broad-spectrum carbapenem with a possible role against some emerging resistant species.     

In vitro antibiotic activity of 11 beta-lactam antibiotics in a cancer center

Two-thousand, five-hundred and twenty-four bacterial isolates were tested against 11 new beta-lactam antibiotics in a prospective study conducted in a cancer center. E. coli, P. aeruginosa, and K. pneumoniae were the most common gram-negative organisms isolated, while S. aureus and Enterococcus were the most common organisms among the gram-positive. The new cephalosporins were more active than the semisynthetic penicillins against E. coli, P. aeruginosa, and K. pneumoniae (p less than 0.001). Mezlocillin had better activity than the other semisynthetic penicillins against most of the gram-negative organisms as well as the enterococci. As a result, mezlocillin was preferred as a beta-lactam agent to be employed with an aminoglycoside as empiric antibiotics for febrile patients with neoplasia.     

Antimicrobial resistance of gram-negative isolates from intensive care units in Turkey: comparison to previous three years

Resistance rates to selected antibiotics of gram-negative bacteria isolated from intensive care units (ICU) of 16 Turkish hospitals during 1998 were evaluated and compared to data from the previous 3 years. Antibiotic susceptibilities to imipenem, ceftazidime, ceftazidime-clavulanate, cefoperazone-sulbactam, ceftriaxone, cefepime, cefodizime, cefuroxime, piperacillin-tazobactam, ticarcillin-clavulanate, gentamicin, amikacin and ciprofloxacin were determined by Etest. A total of 1,404 isolates from 1,060 patients were collected, mainly from urinary and respiratory tracts. As in the previous 3 years, Pseudomonas spp. was the most frequently isolated gram-negative species (29.7%), followed by Escherichia coli, Acinetobacter and Klebsiella spp. Imipenem was the most active in vitro agent (73.4% susceptible), followed by ciprofloxacin (60.6%), cefoperazone-sulbactam (58.7%), cefepime (56.7%), piperacillin-tazobactam (55.0%) and amikacin (54.7%). In 1996, a decline in susceptibility rates of all antibiotics was evident. With the exception of imipenem, resistance to which remained stable, rates somewhat increased in 1997. In 1998, susceptibility to imipenem and cefepime remained stable, amikacin resistance tended to increase and susceptibility rates to other antibacterials showed a favorable increase. These results may in part be due to the implementation of a surveillance program and increased understanding of the magnitude of the resistance problem.     

Susceptibility of 497 clinical isolates of gram-negative anaerobes to trovafloxacin and eight other antibiotics

Trovafloxacin is a novel investigational trifluoronaphthyridone antibiotic with broad-spectrum activity against Gram-positive and Gram-negative organisms. Its in-vitro activity and those of eight other antimicrobial agents were evaluated against 497 clinical isolates of Gram-negative anaerobic bacteria by the agar dilution method. Trovafloxacin had excellent activity, with a minimum inhibitory concentration (MIC) range of <0.03-4 microg/ml, against all species. Out of the 497 isolates tested, 496 (99.5%) were inhibited by a concentration of < or = 2.0 microg/ml of trovafloxacin; the remaining two strains were inhibited by a concentration of 4.0 microg/ml. The MIC50s and MIC90s were 0.12 microg/ml and 1.0 microg/ml, respectively. Meropenem, imipenem and piperacillin/tazobactam were also very active. Overall, at the MIC90s, trovafloxacin was as active as meropenem, slightly more active than metronidazole and imipenem, twice as active as amoxicillin-clavulanic acid, five times more active than piperacillintazobactam and 68 times more active than clindamycin. About 21% of the isolates were resistant to cefoxitin, 30% to clindamycin and 40% to piperacillin. Five species in the Bacteroides fragilis group of isolates were highly resistant to metronidazole (MIC >128 microg/ml). In general, the relatively more resistant species were the B. vulgatus, B. ovatus, B. thetaiotaomicron, and B. fragilis sensu stricto, in that order. All the isolates of the B. fragilis group and about 50% of the Prevotella spp. were beta-lactamase positive. Trovafloxacin certainly holds promise as an alternative drug for therapy of anaerobic infections.     

老年中心型肺癌并发阻塞性肺炎的病原菌分布及耐药性监测

目的:研究老年中心型肺癌并发阻塞性肺炎的病原菌分布及耐药性监测。方法:选自我院于2015年11月至2017年11月期间收治的老年中心型肺癌并发阻塞性肺炎患者122例作为观察对象。分离、培养、鉴定患者病原菌并进行药敏试验。观察病原菌分布特点、主要革兰阳性菌及革兰阴性菌对抗菌药物耐药情况。结果:122例老年中心型肺癌并发阻塞性肺炎患者共分离培养病原菌144株,其中革兰阳性菌56株、革兰阴性菌82株、真菌6株。表皮葡萄球菌对红霉素及青霉素G耐药率较高,分别为80.0%和100.0%;金黄色葡萄球菌对红霉素及青霉素G耐药率较高,分别为90.9%和100.0%。铜绿假单胞菌对美罗培南及头孢哌酮耐药率较高,分别为85.7%和92.9%;肺炎克雷伯菌对头孢曲松及左氧氟沙星耐药率较高,分别为87.5%和93.8%。结论:老年中心型肺癌并发阻塞性肺炎的病原菌分布以革兰阴性菌为主,且对部分抗菌药物耐药明显,值得临床上注意。     

Bacterial isolates from severe infections and their antibiotic susceptibility patterns in Italy: a nationwide study in the hospital setting

The most frequent agents of severe bacterial infections and their antibiotic susceptibility patterns were determined in patients admitted to 45 Italian hospitals over the years 2002-2003. The most common diagnoses were: sepsis (33.8%), pneumonia (9.4%), intravascular catheter-associated infections (9.3%) and ventilator-associated pneumonia (8.1%). Overall, 5115 bacterial isolates were identified from 4228 patients. Three bacterial species, Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli, accounted for more than 50% of the isolates. Other prevalent bacterial isolates were Staphylococcus epidermidis and Enterococcus faecalis, while Acinetobacter baumanii ranked third among all Intensive Care Unit (ICU) isolates. 7% of S. aureus had intermediate resistance to vancomycin. Although E. faecalis displayed no vancomycin resistance, 34% of vancomycin-resistant isolates were found among Enterococcus faecium, one of the highest rates found to date, emphasizing the difference between these two enterococcal species. All the Gram-positive pathogens were susceptible to linezolid, with the exception of approximately 2% of the enterococcal isolates that were intermediate with a minimum inhibitory concentration (MIC)=4 microg/ml. Almost 10% of Escherichia coli, 14% of Klebsiella pneumoniae, 22% of Serratia marcescens and 50% of Enterobacter cloacae were non-susceptible to cefotaxime. Amikacin was the most active antibiotic against P. aeruginosa that showed lack of susceptibility to ceftazidime, gentamicin, piperacillin and ciprofloxacin ranging from 20 to 35%. Finally, Acinetobacter baumanii showed a high level of resistance to all the antibiotics tested including imipenem (58%). The results obtained in this study, the first of its kind in Italy, offer indications for guiding empirical therapy and implementing specific interventions to fight antibiotic-resistant bacterial infections and their transmission in the hospital setting in Italy.     

In vitro antibacterial activity of S-4661, a new parenteral carbapenem,against urological pathogens isolated from patients with complicated urinary tract infections

The antibacterial activity of S-4661, a new parenteral carbapenem antibiotic, was assessed against the major urological pathogens isolated from patients with complicated urinary tract infections. S-4661 was slightly less active than imipenem and panipenem, but more active than meropenem and ceftazidime against Gram-positive bacteria. Against Gram-negative bacteria, S-4661 was similar to meropenem, similar to or more effective than imipenem, and more active than panipenem and ceftazidime. Thus S-4661 possesses potent and well-balanced wide-spectrum antibacterial activity against various urological pathogens.     

Trending eight years of in vitro activity of ertapenem and comparators against Escherichia coli from intra-abdominal infections in North America--SMART 2002-2009

During 2002 - 2009, 2,885 Escherichia coli intra-abdominal isolates were collected from North America in the Study for monitoring Antimicrobial Resistance trends (SmARt) surveillance program. the incidence of extendedspectrum beta-lactamase producing isolates ranged from 1.7% in 2005 to 7.2% in 2004 and 2006, and was 6.8% in 2009. Susceptibility trends showed that there were only minor fluctuations in susceptibility to ertapenem and imipenem with no significant decrease over time. By contrast, cefepime, cefotaxime, cefoxitin, ceftazidime, ceftriaxone, ciprofloxacin, and levofloxacin exhibited significantly higher minimum inhibitory concentrations against E. coli overall (p<0.05) and (except for cefoxitin) against extended-spectrum beta-lactamase producing isolates. Piperacillin-tazobactam also had significantly diminished activity against E. coli overall, but paradoxically showed significantly increased activity against extendedspectrum beta-lactamase producing isolates. Ertapenem and imipenem susceptibility of E. coli in North America remained consistently high during the period 2002 through 2009, and continuing updates from SMART will be helpful in detecting any changes that occur in the future.