Mechanisms of carbapenem resistance among a collection of Enterobacteriaceae clinical isolates in a Texas city
Fourteen Enterobacteriaceae isolates with ertapenem MIC >2 mg/mL were analyzed to identify mechanisms of resistance. All isolates produced extended-spectrum beta-lactamase or AmpC beta-lactamase with variable, but decreased, expression of outer membrane proteins. One Enterobacter cloacae produced derepressed AmpC beta-lactamase, 1 Escherichia coli expressed plasmid-mediated AmpC beta-lactamase, and 1 E. cloacae produced a carbapenemase.
Available from: David Burgess
- "A total of 30 cases received an aminoglycoside, 20% (6/30) of cases as monotherapy and 80% (24/30) as combination therapy
[8-13,16,19,22,40,42,47,48,55,64-68]. There was no significant difference in treatment failure rates between those who received aminoglycoside monotherapy compared to combination therapy (0% vs. 17%; p= 0.6). "
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ABSTRACT: The emergence of Klebsiella pneumoniae carbapenemases (KPCs) producing bacteria has become a significant global public health challenge while the optimal treatment remains undefined. We performed a systematic review of published studies and reports of treatment outcomes of KPC infections using MEDLINE (2001–2011). Articles or cases were excluded if one of the following was fulfilled: no individual patient data provided, no treatment regimen specified, no treatment outcome specified, report of colonization, or greater than three antibiotics were used to treat the KPC infection. Data extracted included patient demographics, site of infection, organism, KPC subtype, antimicrobial therapy directed at KPC-infection, and treatment outcome. Statistical analysis was performed in an exploratory manner. A total of 38 articles comprising 105 cases were included in the analysis. The majority of infections were due to K. pneumoniae (89%). The most common site of infection was blood (52%), followed by respiratory (30%), and urine (10%). Forty-nine (47%) cases received monotherapy and 56 (53%) cases received combination therapy directed at the KPC-infection. Significantly more treatment failures were seen in cases that received monotherapy compared to cases who received combination therapy (49% vs 25%; p= 0.01). Respiratory infections were associated with higher rates of treatment failure with monotherapy compared to combination therapy (67% vs 29% p= 0.03). Polymyxin monotherapy was associated with higher treatment failure rates compared to polymyxin-based combination therapy (73% vs 29%; p= 0.02); similarly, higher treatment failure rates were seen with carbapenem monotherapy compared to carbapenem-based combination therapy (60% vs 26%; p= 0.03). Overall treatment failure rates were not significantly different in the three most common antibiotic-class combinations: polymyxin plus carbapenem, polymyxin plus tigecycline, polymyxin plus aminoglycoside (30%, 29%, and 25% respectively; p=0.6). In conclusion, combination therapy is recommended for the treatment of KPC infections; however, which combination of antimicrobial agents needs to be established in future prospective clinical trials.
Annals of Clinical Microbiology and Antimicrobials 12/2012; 11(1). DOI:10.1186/1476-0711-11-32 · 2.19 Impact Factor
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ABSTRACT: Enterobacteriaceae other than Escherichia spp. and Klebsiella spp. are recognisable for their increasing resistance. Plasmid-mediated beta-lactamases, including extended-spectrum beta-lactamases (ESBLs), plasmid-mediated AmpC beta-lactamases (pAmpCs) and the newly emerged KPC, play an important role in beta-lactam resistance. In this study, we investigated the genetic characteristics of plasmid-mediated beta-lactamases amongst non-Escherichia, non-Klebsiella Enterobacteriaceae that were non-susceptible to at least a broad-spectrum cephalosporin. A total of 143 (23.9%) of 598 isolates during the 6-month study period met the screening criteria, amongst which 142 (99.3%) and 99 (69.2%) isolates carried ESBL and pAmpC genes, respectively. Resistance genotypes were described. bla(KPC) was not detected in isolates with reduced susceptibility to carbapenems. This study provides an insight into plasmid-mediated resistance determinants amongst cephalosporin-non-susceptible Enterobacteriaceae other than Escherichia spp. and Klebsiella spp.
International journal of antimicrobial agents 10/2010; 36(4):343-7. DOI:10.1016/j.ijantimicag.2010.06.029 · 4.30 Impact Factor
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