R. Badal

Kaohsiung Medical University, Kao-hsiung-shih, Kaohsiung, Taiwan

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Publications (75)101.09 Total impact

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    ABSTRACT: The study for monitoring antimicrobial resistance trends (SMART) surveillance program monitors the epidemiology and trends in antibiotic resistance of intra-abdominal pathogens to currently used therapies. The current report describes such trends during 2010-2011. A total of 25 746 Gram-negative clinical isolates from intra-abdominal infections were collected and classified as hospital-associated (HA) if the hospital length of stay (LOS) at the time of specimen collection was ≧48 hours, community-associated (CA) if LOS at the time of specimen collection was <48 hours, or unknown (no designation given by participating centre). A total of 92 different species were collected of which the most common was Escherichia coli: 39% of all isolates in North America to 55% in Africa. Klebsiella pneumoniae was the second most common pathogen: 11% of all isolates from Europe to 19% of all isolates from Asia. Isolates were from multiple intra-abdominal sources of which 32% were peritoneal fluid, 20% were intra-abdominal abscesses, and 16·5% were gall bladder infections. Isolates were further classified as HA (55% of all isolates), CA (39% of all isolates), or unknown (6% of all isolates). The most active antibiotics tested were imipenem, ertapenem, amikacin, and piperacillin-tazobactam. Resistance rates to all other antibiotics tested were high. Considering the current data set and high-level resistance of intra-abdominal pathogens to various antibiotics, further monitoring of the epidemiology of intra-abdominal infections and their susceptibility to antibiotics through SMART is warranted.
    Journal of chemotherapy (Florence, Italy) 02/2014; · 0.83 Impact Factor
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    ABSTRACT: A sub-set of Escherichia coli, Klebsiella oxytoca, Klebsiella pneumoniae and Proteus mirabilis collected for the Study for Monitoring Antimicrobial Resistance Trends (SMART) that were positive for the CLSI extended-spectrum beta-lactamase (ESBL) phenotypic confirmatory test (N=3,245) or had an ertapenem MIC of ≥0.5μg/ml (N=293) or both (N=467) were analyzed for ESBL genes. Most ESBL phenotype E. coli or K. pneumoniae possessed an ESBL gene (95.8% & 88.4%, respectively) or 93.1% if carbapenem non-susceptible K. pneumoniae were removed. This rate was lower for P. mirabilis (73.4%) and K. oxytoca (62.5%). Virtually all ESBL-positive isolates (99.5%) were cefotaxime non-susceptible (CLSI or EUCAST breakpoints). Fewer (82%) were ceftazidime non-susceptible (CLSI breakpoints). Also 21.1% of E. coli, 25% of K. oxytoca and 78.7% of P. mirabilis were ceftazidime-susceptible but ESBL-positive. This suggests CLSI breakpoints for ceftazidime are too high to detect ESBLs. The lower EUCAST breakpoints detected ESBLs in E. coli and K. oxytoca better, but 59.6% of ESBL-positive isolates of P. mirabilis were ceftazidime-susceptible. For isolates with ertapenem MIC ≥ 0.5μg/ml, more accurate ESBL phenotype analysis was observed for E. coli and K. pneumoniae (sensitivity >95% for both, specificity 94.4% and 54.1%, respectively). If carbapenemase-positive K. pneumoniae were excluded specificity increased to 78%. The positive predictive values for the ESBL phenotypic test with E. coli and K. pneumoniae were 97.6% and 81.8%, respectively and negative predictive values were 75.9% and 95.2%, respectively. We therefore suggest it would be prudent to confirm phenotypic ESBL-positive P. mirabilis, K. pneumoniae and K. oxytoca with molecular analysis.
    Journal of Medical Microbiology 01/2014; · 2.30 Impact Factor
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    ABSTRACT: The Study for Monitoring Antimicrobial Resistance Trends (SMART) has been monitoring the activity of antimicrobials indicated for the treatment of Intra-abdominal infections since 2004. This report documents the in vitro activity of several recommended antimicrobials against 3449 gram-negative bacilli isolated from the 30 and 25 participating sites in North America in 2010-2011 respectively and characterizes the extended-spectrum beta-lactamases identified in ESBL positive and ertapenem non-susceptible isolates of Enterobacteriaceae. Escherichia coli, Klebsiella pneumonie, Enterobacter cloacae, Proteus mirabilis, Klebsiella oxytoca, Citrobacter freundii, Enterobacter aerogenes, Serratia marcescens and Morganella morgannii were the most common species isolated. The incidence of beta-lactamase production was 8.8% and 8.9% for E. coli and K. pneumoniae respectively. Overall the most active antimicrobials were amikacin, piperacillin-tazobactam, imipenem and ertapenem although beta-lactamase production reduced the activity of most agents. Characterization of beta-lactamase genes determined that blaSHV, blaCTX-M, blaAmpC and blaKPC were commonly found in most beta-lactamase positive isolates.
    Diagnostic Microbiology and Infectious Disease. 01/2014;
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    ABSTRACT: During 2011, a total of 1,442 gram-negative pathogens from intra-abdominal infections were collected as part of the Study for Monitoring Antimicrobial Resistance Trends (SMART) from 19 hospital sites within the United States. Susceptibility to ertapenem and comparators and molecular analysis of ertapenem resistant isolates was performed. Extended-spectrum beta-lactamase ESBL (ESBL) isolates were determined using the Clinical and Laboratory Standards Institute's recommended phenotypic test. Isolates were identified to the species level, and tested for antimicrobial susceptibility using custom MicroScan dehydrated broth microdilution panels ESBLs and carbapenemases were characterized using the Check-Points microarray. Strain typing of K. pneumoniae was performed by rep-PCR on the DiversiLab System. The majority of isolates were Escherichia coli (36%), Klebsiella pneumoniae (18.6%), Pseudomonas aeruginosa (12.1%) and Enterobacter cloacae (8.4%). Incidence of ESBL-positive isolates was 12.7%, 9.7%, 3.6% and 3.1% for K. pneumoniae, E. coli, Proteus mirabilis and K. oxytoca, respectively. Against the majority of isolates and species tested, the most active antibiotics were amikacin, ertapenem, and imipenem, with the carbapenems being the most active in vitro, including against ESBL-positive isolates of E. coli. All other antibiotics exhibited diminished activity. Against K. pneumoniae, the carbapenems were notably less active against ESBL-positive isolates though their activity against this sub-population was still the highest of all antibiotics tested; however, 41.1% (14 of 34) of the phenotypically ESBL-positive K. pneumoniae co-produced a carbapenemase (KPC2 or KPC3), and >90% of the isolates producing only an ESBL remained susceptible to ertapenem. Further monitoring of susceptibility of intra-abdominal isolates is warranted due to limited therapeutic options available to physicians.
    The Journal of infection 09/2013; · 4.13 Impact Factor
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    ABSTRACT: E-1174 Comparative in vitro Activity of Ceftaroline and Comparators against Skin and Soft Tissue Infections (SSTI) Pathogens in Asia-Pacific -AWARE Surveillance Program 2012 I. Morrissey1, D. Hoban2, R. Badal2, M. Hackel2, S. Bouchillon2, D. Biedenbach2, J. Ambler3; 1IHMA Europe Sàrl, Epalinges, SWITZERLAND, 2IHMA, Inc., Schaumburg, IL, 3AstraZeneca Pharmaceuticals, Waltham, MA. Background: Ceftaroline (CPT) is a new cephalosporin with in vitro activity against Gram-positive organisms (including methicillin-resistant Staphylococcus aureus [MRSA]) and common Enterobacteriaceae (excluding strains producing a broad range of beta-lactamases [BLs]). The activity of CPT and comparators against SSTI pathogens isolated in 2012 from Asia-Pacific (A-P) region is summarized. Methods: 1,301 SSTI pathogens were collected from China (9 sites), Japan (3), Philippines (3), South Korea (2), Taiwan (3), Thailand (3), and Australia (3). MICs were determined and the results interpreted by CLSI broth microdilution performance standards. Extended-spectrum BLs (ESBLs) were confirmed phenotypically according to CLSI methodology. Results: Percentage susceptibility to CPT and selected comparators is shown below. Values ≥90% are shaded, na=no breakpoints, and dash indicates not tested. Conclusions: CPT demonstrated in vitro activity against Gram-positive bacteria, but had variable activity against Gram-negative Enterobacteriaceae from SSTI in A-P.
    53rd Interscience Conference on Antimicrobial Agents and Chemotherapy, Denver, Co; 09/2013
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    ABSTRACT: The objective of this study was to investigate the susceptibility of hospital- and community-associated Escherichia coli and Klebsiella pneumoniae isolated from patients with intra-abdominal infections in China. From 2002 to 2011, the minimum inhibitory concentrations (MICs) of 12 antibiotics against 3,074 E. coli and 1,025 K. pneumoniae from 23 centers located in 16 cities were determined by the broth microdilution method. During the ten-year study period, ertapenem, imipenem, amikacin and piperacillin-tazobactam retained high and stable activity against E .coli and K. pneumoniae isolates regardless of their source (hospital-associated [HA] or community-associated [CA]) and extended-spectrum beta-lactamase (ESBL) production. However, the susceptibility of E. coli to cephalosporins and ampicillin-sulbactam decreased dramatically during the ten years, especially for the CA isolates. Fluoroquinolones showed low activity against E. coli. During the whole study period, the ESBL rates for E. coli isolates from IAIs increased from 36.1% in 2002-2003 to 68.1% in 2010-2011 (P<0.001). Correspondingly, the ESBL rates in HA isolates increased from 52.2% in 2002-2003 to70.0% in 2010-2011 (P=0.001), and in CA isolates from 19.1% in 2002-2003 to 61.6% in 2010-2011 (P<0.001). The ESBL-positive rate in K. pneumoniae remained between 30.1-39.3% of the total isolates with no significant change during the ten years. In conclusion, carbapenems retained the highest susceptibility rates against HA and CA E. coli and K. pneumoniae. High prevalence of ESBL in HA E. coli and fast-growing resistance in CA E. coli severely limit the empirical use of the third- and fourth-generation cephalosporins in the therapy of intra-abdominal infections.
    Journal of Medical Microbiology 06/2013; · 2.30 Impact Factor
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    ABSTRACT: Antimicrobial resistance has been increasing for several years and is often higher in intensive care units (ICUs) than in other facilities. The spread of extended-spectrum β-lactamases (ESBLs) in particular has profoundly impacted antimicrobial efficacy and usage. The Study for Monitoring Antimicrobial Resistance Trends has monitored the in vitro activity of ertapenem and several comparators against aerobic gram-negative bacteria from intra-abdominal infections (IAIs) for many years. This report summarizes susceptibility levels and epidemiology for key IAI pathogens cultured from general pediatric medical wards and pediatric ICUs globally. 1248 gram-negative bacteria were collected from pediatric IAIs by 113 labs in 40 countries from 2008 to 2010. Susceptibility was determined by Clinical and Laboratory Standards Institute broth microdilution. Susceptibility rates (%S) were determined for species with ≥10 isolates. Sixty-two percent of isolates came from general pediatric wards and 38% from pediatric ICUs. The overall ESBL-positive rate was 11.0% for Escherichia coli and 38.9% for Klebsiella pneumoniae; the ESBL-positive rate for E. coli was twice as high in ICU as non-ICU. Most study drugs inhibited >90% of ESBL-negative isolates, but only the carbapenems inhibited >90% of ESBL-positive E. coli and only imipenem inhibited >90% of ESBL-positive K. pneumoniae. Amikacin, imipenem and ertapenem were the most active against gram-negative bacteria from pediatric IAIs, followed closely by the fluoroquinolones and cefepime. Other cephalosporins were often <90% active. ESBL rates were 38.9% for K. pneumoniae and 11.0% for E. coli. Therapy for pediatric IAIs should take into consideration local ESBL rates because only carbapenems inhibited most of these pathogens.
    The Pediatric Infectious Disease Journal 06/2013; 32(6):636-40. · 3.57 Impact Factor
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    ABSTRACT: BACKGROUND: The Study for Monitoring Antimicrobial Resistance Trends is an ongoing global surveillance program that has monitored the susceptibilities of Gram-negative bacilli from inpatient urinary tract infections (UTIs) since late 2009. OBJECTIVE: This analysis reports on the in vitro susceptibility of 2,135 isolates collected by 24 US sites from hospitalized patients with UTIs between 2009 and 2011. METHODS: Minimum inhibitory concentrations and susceptibility were determined according to the guidelines of the Clinical and Laboratory Standards Institute. RESULTS: Of the isolates collected, 88.6% (1,892) were Enterobacteriaceae, which included 48.9% (n = 1,045) Escherichia coli, 14.5% (n = 310) Klebsiella pneumoniae, 6.4% (n = 136) Proteus mirabilis, 2.5% (n = 54) Klebsiella oxytoca, and 16.3% (n = 347) other Enterobacteriaceae species. Overall, 6.8% of E coli, 10.3% of K pneumoniae, 3.7% of P mirabilis, and 11.1% of K oxytoca isolates were extended-spectrum β-lactamase-producing strains. Of the Enterobacteriaceae isolates, 67.5% were community associated and 26.9% were hospital associated (5.7% had no demographics). Highest overall rates of activity for the study period were seen with amikacin, ertapenem, and imipenem. The least active antimicrobials tested were ampicillin-sulbactam, ciprofloxacin, and levofloxacin. CONCLUSIONS: Ertapenem, imipenem, and amikacin were the most active study drugs against extended-spectrum β-lactamase-producing strains, although the activity against extended-spectrum β-lactamase-producing K pneumoniae did not exceed 69% throughout the study period. The results of the Study for Monitoring Antimicrobial Resistance Trends surveillance study document the rates of antimicrobial resistance in UTI pathogens in the United States, which can assist health care practitioners in selecting the appropriate treatment for UTIs.
    Clinical Therapeutics 04/2013; · 2.23 Impact Factor
  • Wang-Huei Sheng, Robert E Badal, Po-Ren Hseuh
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    ABSTRACT: The increasing trend of β-lactam resistance among Enterobacteriaceae is a worldwide threat. Enterobacteriaceae isolates causing intra-abdominal infections (IAI) from the Study for Monitoring Antimicrobial Resistance Trends (SMART) collected in 2008 and 2009 from the Asia-Pacific region were investigated. Detection of extended-spectrum β-lactamases (ESBLs), AmpC β-lactamases, and carbapenemases was performed by multiplex PCR. A total of 699 Enterobacteriaceae isolates with positive genotypic results, included Escherichia coli (n=443), Klebsiella pneumoniae (n=187), Enterobacter cloacae (n=45), K. oxytoca (n=9), Citrobacter freundii (n=5), Proteus mirabilis (n=3), E. aerogenes (n=2), Morganella morganii (n=2), and one each of E. asburiae, P. vulgaris and Providencia rettgeri were analyzed. Nearly 20% of these β-lactamase producing Enterobacteriaceae isolates were from community-associated IAI. CTX-M (588 isolates, including 428 [72.8%] with CTX-M-15) was the most common ESBL, followed by SHV (n=59) and TEM (n=4). CMY (n=110, including 102 [92.7%] with CMY-2) was the most common AmpC β-lactamase, followed by DHA (n=46) and ACT/MIR (n=40). NDM (n=65, including 62 [95.4%] with NDM-1) was the most common carbapenemase, followed by IMP (n=7) and OXA (n=7). Isolates from hospital-associated IAI had more complicated β-lactamase combinations than isolates from the community. Carbapenemases were all exclusively detected in Enterobacteriaceae isolates from India, except IMP β-lactamases were also detected in the Philippines and Australia. CTX-M β-lactamases were the predominant ESBLs produced by Enterobacteriaceae causing IAI in Asia-Pacific. Emergence of CTX-M-15, CMY-2 and NDM-1 producing Enterobacteriaceae isolates is of major concern and highlights the need for further surveillance in this area.
    Antimicrobial Agents and Chemotherapy 04/2013; · 4.57 Impact Factor
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    ABSTRACT: Abstract Background: The Study for Monitoring Antimicrobial Resistance Trends (SMART) has tracked the in vitro activity of ertapenem and comparators against aerobic gram-negative bacteria from intra-abdominal infections since 2002. This report describes the epidemiology and susceptibility for clinical isolates associated with appendicitis, collected from 2008 to 2010. Methods: A total of 1,720 gram-negative bacilli were collected from patients with appendicitis in 122 hospitals in 39 countries worldwide; of these, 23% of isolates were from pediatric patients (≤17 years old). Minimum inhibitory concentrations (MICs) and extended-spectrum β-lactamase (ESBL) phenotypes were determined by broth microdilution and interpreted using Clinical and Laboratory Standards Institute guidelines. Results: The global ESBL-positive rate was 16.3%, ranging from 2.2% for Proteus mirabilis to 16.6% for Escherichia coli and 20.1% for Klebsiella pneumoniae. The ESBL-positive rates differed by age group (17.7% in adults vs. 11.4% in children) and by geographic region, with significantly higher rates in Asia/Pacific (28.0%) and significantly lower rates in North America (9.1%), Africa/Middle East (4.8%), and Europe (4.4%). Amikacin, imipenem-cilastatin, piperacillin-tazobactam, and ertapenem were the most active of the tested agents against aerobic gram-negative appendicitis pathogens across pediatric and adult age groups and across geographic regions, including ESBL-positive isolates. Cefepime and ceftazidime were active against ≥90% of global pediatric isolates. E. coli, by far the most frequently isolated species (68% in adults and 75% in pediatric patients), was significantly less susceptible in adults than in pediatric patients (p<0.05; Fisher exact test) to all tested agents except amikacin, ertapenem, imipenem-cilastatin, piperacillin-tazobactam, and ampicillin-sulbactam (with the latter showing low activity in both age groups). Conclusions: These in vitro data suggest that amikacin, imipenem-cilastatin, piperacillin-tazobactam, and ertapenem would perform well against aerobic gram-negative bacilli associated with appendicitis in both adults and children, especially in regions with high rates of ESBL-positive E. coli.
    Surgical Infections 03/2013; · 1.87 Impact Factor
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    ABSTRACT: This report summarizes data from the Study for Monitoring Antimicrobial Resistance Trends 2005-2010 to identify trends in susceptibility from intra-abdominal infections in North America. Escherichia coli and Klebsiella pneumoniae were the most frequently isolated pathogens. Extended-spectrum beta-lactamase rates (%) in 2005/2010 for E. coli and K. pneumoniae were 1.7/7.3 and 3.2/13.1, respectively. Ertapenem, imipenem, amikacin, and cefoxitin showed stable susceptibility.
    Diagnostic microbiology and infectious disease 03/2013; · 2.45 Impact Factor
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    ABSTRACT: During 2002-2010, a total of 30840 Escherichia coli clinical isolates from intra-abdominal infections were collected globally in the Study for Monitoring Antimicrobial Resistance Trends (SMART) surveillance programme. The incidence of extended-spectrum β-lactamase (ESBL)-producing isolates ranged from 9.2% in 2002 to 21.2% in 2010. The highest rates were observed in Asia (38.3%) and Latin America (22.9%) and the lowest rates in Africa (6.3%), North America (6%) and South Pacific (5.8%). Global susceptibility trends showed that there were only minor fluctuations in susceptibility to ertapenem and imipenem, with no significant decrease over time. Against ESBL-positive isolates, ertapenem susceptibility significantly increased during 2002-2010 globally. Moreover, susceptibility to ertapenem in the different geographical regions studied was also high, with only minor fluctuations generally observed. Notably, in Asia where the highest ESBL-positives rates (38.3%) were observed, susceptibility to ertapenem had actually significantly increased in this population during the 9-year study period. By contrast, susceptibility to amikacin, cephalosporins, fluoroquinolones and β-lactam/β-lactamase inhibitor combinations generally decreased over time. Further monitoring of the susceptibility to ertapenem and other antibiotics through SMART is warranted.
    International journal of antimicrobial agents 01/2013; · 3.03 Impact Factor
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    ABSTRACT: Surveillance of antimicrobial agent resistance provides important information to guide microbiologists and infectious disease specialists understanding of the control and the spread of resistance mechanisms within the local environment. Continued monitoring of antimicrobial resistance patterns in the community and in local hospital environments is essential to guide effective empiric therapy. The Study for Monitoring Antimicrobial Resistance Trends (SMART) has monitored the in vitro susceptibility patterns of clinical Gram-negative bacilli to antimicrobial agents collected worldwide from intra-abdominal infections since 2002 and urinary tract infections since 2009. Resistance trends, with a particular focus on carbapenem resistance and the rate of extended-spectrum β-lactamases (ESBLs), were analyzed. Isolates from intra-abdominal infections (n = 92,086) and urinary-tract infections (n = 24,705) were collected and tested using Clinical and Laboratory Standards Institute methods. This review presents carbapenem susceptibility and ESBL rates over ten years of SMART study analysis, including key publications during this period. The SMART study has proved to be a valuable resource in determining pathogen prevalence and antibiotic susceptibility over the last ten years and continues to provide evidence for regulatory susceptibility breakpoints and clinical decision making.
    Pharmaceuticals 01/2013; 6(11):1335-1346.
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    ABSTRACT: In 2009-2010, 3646 urinary tract isolates of Enterobacteriaceae spp. were isolated from hospitalized patients in North America and Europe. Extended-spectrum beta-lactamase (ESBL) production was detected in 8.5% and 8.8% of Escherichia coli and Klebsiella pneumoniae, respectively, in North America and in 17.6% and 38.9% for Europe, respectively. The carbapenems (ertapenem and imipenem) were the most active agents in vitro, with ampicillin-sulbactam the least active. Molecular characterization of about 50% of ESBL-positive isolates identified the presence of bla(CTX-M) genes in over 90% of Escherichia coli from both continents. bla(KPC) was more common in North American isolates of K. pneumoniae than in European isolates (21.4% versus 6.9%). bla(TEM) and AmpC genes were infrequent. Enterobacteriaceae spp. isolated from hospitalized patients with urinary tract infections in both North America and Europe are often resistant to commonly used antimicrobials with bla(CTX-M) genes common in both Escherichia coli and K. pneumoniae.
    Diagnostic microbiology and infectious disease 07/2012; 74(1):62-7. · 2.45 Impact Factor
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    ABSTRACT: The worldwide dissemination of extended-spectrum-β-lactamase (ESBL)- and carbapenemase-producing Enterobacteriaceae is a major concern in both hospital and community settings. Rapid identification of these resistant pathogens and the genetic determinants they possess is needed to assist in clinical practice and epidemiological studies. A collection of Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca, and Proteus mirabilis isolates, including phenotypically ESBL-positive (n = 1,093) and ESBL-negative isolates (n = 59), obtained in 2008-2009 from a longitudinal surveillance study (SMART) was examined using an in vitro nucleic acid-based microarray. This approach was used to detect and identify bla(ESBL) (bla(SHV), bla(TEM), and bla(CTX-M) genes of groups 1, 2, 9, and 8/25) and bla(KPC) genes and was combined with selective PCR amplification and DNA sequencing for complete characterization of the bla(ESBL) and bla(KPC) genes. Of the 1,093 phenotypically ESBL-positive isolates, 1,041 were identified as possessing at least one bla(ESBL) gene (95.2% concordance), and 59 phenotypically ESBL-negative isolates, used as negative controls, were negative. Several ESBL variants of bla(TEM) (n = 5), bla(SHV) (n = 11), bla(CTX-M) (n = 19), and bla(KPC) (n = 3) were detected. A new bla(SHV) variant, bla(SHV-129), and a new bla(KPC) variant, bla(KPC-11), were also identified. The most common bla genes found in this study were bla(CTX-M-15), bla(CTX-M-14), and bla(SHV-12). Using nucleic acid microarrays, we obtained a "molecular snapshot" of bla(ESBL) genes in a current global population; we report that CTX-M-15 is still the dominant ESBL and provide the first report of the new β-lactamase variants bla(SHV-129) and bla(KPC-11).
    Journal of clinical microbiology 02/2012; 50(5):1632-9. · 4.16 Impact Factor
  • The Journal of infection 02/2012; 64(6):620-2. · 4.13 Impact Factor
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    ABSTRACT: The Study for Monitoring Antimicrobial Resistance Trends (SMART) follows trends in resistance among aerobic and facultative anaerobic gram-negative bacilli (GNB) isolated from complicated intra-abdominal infections (cIAIs) in patients around the world. During 2004-2009, three centralized clinical microbiology laboratories serving 59 private hospitals in three large South African cities collected 1,218 GNB from complicated intra-abdominal infections (cIAIs) and tested them for susceptibility to 12 antibiotics according to the 2011 Clinical Laboratory Standards Institute (CLSI) guidelines. Enterobacteriaceae comprised 83.7% of the isolates. Escherichia coli was the species isolated most commonly (46.4%), and 7.6% of these were extended-spectrum β-lactamase (ESBL)-positive. The highest ESBL rate was documented for Klebsiella pneumoniae (41.2%). Overall, ertapenem was the antibiotic most active against susceptible species for which it has breakpoints (94.6%) followed by amikacin (91.9%), piperacillin-tazobactam (89.3%), and imipenem-cilastatin (87.1%), whereas rates of resistance to ceftriaxone, cefotaxime, ciprofloxacin, and levofloxacin were documented to be 29.7%, 28.7%, 22.5%, and 21.1%, respectively. Multi-drug resistance (MDR), defined as resistance to three or more antibiotic classes, was significantly more common in K. pneumoniae (27.9%) than in E. coli (4.9%; p<0.0001) or Proteus mirabilis (4.1%; p<0.05). Applying the new CLSI breakpoints for carbapenems, susceptibility to ertapenem was reduced significantly in ESBL-positive E. coli compared with ESBL-negative isolates (91% vs. 98%; p<0.05), but this did not apply to imipenem-cilastatin (95% vs. 99%; p=0.0928). A large disparity between imipenem-cilastatin and ertapenem susceptibility in P. mirabilis and Morganella morganii was documented (24% vs. 96% and 15% vs. 92%, respectively), as most isolates of these two species had imipenem-cilastatin minimum inhibitory concentrations in the 2-4 mcg/mL range, which is no longer regarded as susceptible. This study documented substantial resistance to standard antimicrobial therapy among GNB commonly isolated from cIAIs in South Africa. With the application of the new CLSI carbapenem breakpoints, discrepancies were noted between ertapenem and imipenem-cilastatin with regard to the changes in their individual susceptibilities. Longitudinal surveillance of susceptibility patterns is useful to guide recommendations for empiric antibiotic use in cIAIs.
    Surgical Infections 02/2012; 13(1):43-9. · 1.87 Impact Factor
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    ABSTRACT: The Study for Monitoring Antimicrobial Resistance Trends is an ongoing multi-year surveillance study that tracks worldwide antimicrobial resistance trends among aerobic and facultatively anaerobic Gram-negative bacilli isolated from intra-abdominal infections. During 2008-2009, 1366 isolates of Escherichia coli were collected from 19 investigator sites in 11 Latin American countries. Of the 1366 isolates, 323 (23.6%) were extended spectrum beta-lactamase (ESBL)-positive. Overall, the most effective agents tested were imipenem, ertapenem, and amikacin with susceptibilities of ≥96%. Against ESBL-positive isolates, only imipenem and ertapenem exhibited susceptibility ≥90%. Based on the use of the new Clinical and Laboratory Standards Institute clinical breakpoints for ertapenem (resistance ≥1 μg/ml), resistance to ertapenem among all E. coli isolates was only 0.3% (4/1366) throughout the region, ranging from 0% in several countries up to 1.2% in Ecuador. Against ESBL-positive isolates only, resistance to ertapenem in Latin America overall was 0.9% (3/323), with a maximum of 9.1% (1/11) observed in Argentina.
    Journal of chemotherapy (Florence, Italy) 01/2012; 24(1):6-11. · 0.83 Impact Factor
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    ABSTRACT: 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.
    Journal of chemotherapy (Florence, Italy) 10/2011; 23(5):266-72. · 0.83 Impact Factor
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    ABSTRACT: Escherichia coli is the most important uropathogen. The Study for Monitoring Antimicrobial Resistance Trends program collected 1643 E. coli isolates in 2009-2010 from urinary tract infection (UTI) specimens of hospitalized patients in countries worldwide. Ertapenem and imipenem were the most active agents tested, inhibiting >98% of all E. coli phenotypes. Overall, 17.9% of isolates were extended-spectrum beta-lactamase (ESBL) producers. The highest ESBL rate was from the Asia/Pacific region (27.7%). Amikacin and piperacillin-tazobactam achieved 90% inhibition levels only for ESBL-negative isolates. Ciprofloxacin and levofloxacin were not effective for ESBL-positive isolates, with only 14.6% and 15.9% susceptible, respectively. These observations highlight the need for continued monitoring of susceptibility of E. coli isolated from hospitalized patients with UTIs.
    Diagnostic microbiology and infectious disease 08/2011; 70(4):507-11. · 2.45 Impact Factor