Susceptibility of gram-negative aerobic bacilli from intra-abdominal pathogens to antimicrobial agents collected in the United States during 2011.

During 2011, a total of 1442 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 Klebsiella pneumoniae was performed by rep-PCR on the DiversiLab System. The majority of isolates were Escherichia coli (36%), K. 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 Klebsiella 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.

Hawser SP ，Badal RE ，Bouchillon SK ，Hoban DJ ，Hackel MA ，Biedenbach DJ ，Goff DA ... -  《-》

Antimicrobial susceptibility and extended-spectrum beta-lactamase rates in aerobic gram-negative bacteria causing intra-abdominal infections in Vietnam: report from the Study for Monitoring Antimicrobial Resistance Trends (SMART 2009-2011).

Treatment options for multidrug-resistant pathogens remain problematic in many regions and individual countries, warranting ongoing surveillance and analysis. Limited antimicrobial susceptibility information is available for pathogens from Vietnam. This study determined the bacterial susceptibility of aerobic gram-negative pathogens of intra-abdominal infections among patients in Vietnam during 2009-2011. A total of 905 isolates were collected from 4 medical centers in this investigation as part of the Study for Monitoring Antimicrobial Resistance Trends. Antimicrobial susceptibility and extended-spectrum beta-lactamase (ESBL) rates among the appropriate species were determined by a central laboratory using Clinical and Laboratory Standards Institute methods. Among the species collected, Escherichia coli (48.1% ESBL-positive) and Klebsiella pneumoniae (39.5% ESBL-positive) represented the majority (46.4%) of the isolates submitted for this study. Ertapenem MIC90 values were lowest for these 2 species at 0.12 and 0.25μg/mL and remained unchanged for ESBL-positive isolates. Imipenem MIC90 values were also the same for all isolates and ESBL-positive strains at 0.25 and 0.5μg/mL, respectively. Ertapenem MIC90 values for additional species with sufficient numbers for analysis, including Enterobacter cloacae, Proteus mirabilis, Acinetobacter baumannii, and Pseudomonas aeruginosa, were 1, 0.06, >4, and >4μg/mL, respectively. Analysis of beta-lactamases in a subset of 132 phenotypically ESBL-positive Enterobacteriaceae demonstrated that CTX-M variants, particularly CTX-M-27 and CTX-M-15, were the predominant enzymes. High resistance rates in Vietnam hospitals dictate continuous monitoring as antimicrobial inactivating enzymes continue to spread throughout Asia and globally.

Biedenbach DJ ，Bouchillon SK ，Hoban DJ ，Hackel M ，Phuong DM ，Nga TT ，Phuong NT ，Phuong TT ，Badal RE ... -  《-》

Etiology, extended-spectrum β-lactamase rates and antimicrobial susceptibility of gram-negative bacilli causing intra-abdominal infections in patients in general pediatric and pediatric intensive care units--global data from the Study for Monitoring Antim

Badal RE ，Bouchillon SK ，Lob SH ，Hackel MA ，Hawser SP ，Hoban DJ ... -  《-》

Antimicrobial susceptibility of Gram-negative bacteria causing intra-abdominal infections in China: SMART China 2011.

Zhang H ，Yang Q ，Xiao M ，Chen M ，Badal RE ，Xu Y ... -  《-》

Antimicrobial susceptibility of Gram-negative organisms from intraabdominal infections and evolution of isolates with extended spectrum β-lactamases in the SMART study in Spain (2002-2010).

Cantón R ，Loza E ，Aznar J ，Calvo J ，Cercenado E ，Cisterna R ，Romo FG ，Hontangas JL ，Calvo CR ，Barrenechea AI ，Tubau F ，Weber I ，Yuste P ，Cavanillas R ，SMART-Spain Working Group ... -  《-》