Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0004610 (bacteremia)
 13,199 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A multiple trauma patient failed treatment with ceftazidime and amikacin for bacteremia and meningitis due to a Klebsiella pneumoniae strain that produced a novel, plasmid-mediated beta-lactamase. Both pre- and posttreatment isolates were resistant to ceftazidime (MIC, greater than or equal to 64 micrograms/ml) and various penicillins but not to other expanded-spectrum cephalosporins. The beta-lactamase had a pI of 5.25 and was encoded on a conjugal plasmid of approximately 150 kilobases. DNA hybridization studies indicated that the enzyme was a TEM derivative.
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PMID:Failure of ceftazidime-amikacin therapy for bacteremia and meningitis due to Klebsiella pneumoniae producing an extended-spectrum beta-lactamase. 220 6

A mouse model of bacteremia was used to compare the efficacies of 1.5- and 3.0-g intravenous doses of ampicillin-sulbactam. Seven strains of Escherichia coli producing various levels of TEM-1 beta-lactamase were used as the challenge isolates. These strains included six clinical isolates (MICs from 2/1 micrograms/ml [with 2 and 1 microgram/ml being the respective concentrations of ampicillin and sulbactam] to 32/16 micrograms/ml) with similar degrees of virulence in mice and a laboratory genetic transformant (E. coli AFE) which hyperproduces TEM-1 (MIC = 128/64 micrograms/ml). Human pharmacokinetics were simulated by injecting mice subcutaneously twice (1 h apart) with ampicillin-sulbactam at concentrations of 40 mg/kg of body weight (1.5 g) and 80 mg/kg (3.0 g). Against two clinical isolates for which ampicillin-sulbactam MICs were < or = 8/4 micrograms/ml, no difference was observed in either the rate or level of killing between the two doses, and both doses were 100% protective against lethal infection. Against the four clinical isolates for which ampicillin-sulbactam MICs were between 16/8 and 32/16 micrograms/ml, a slight delay in killing was noted with three of the strains. This delay was followed by a rapid 2- to 3-log drop in the level of bacteremia, and both doses of ampicillin-sulbactam were 100% protective against lethal septicemia. With strain AFE, no killing was observed with the 40-mg/kg dose compared with a 2-log killing with the 80-mg/kg dose. This difference in killing correlated with a decreased protective efficacy of the 40-mg/kg dose. These data suggest that the 1.5-g preparation of ampicillin-sulbactam is as effective as the 3.0-g dose in the treatment of experimentally induced E. coli bacteremia, as long as ampicillin-sulbactam MICs are 32/16 micrograms/ml or less.
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PMID:Comparison of ampicillin-sulbactam regimens simulating 1.5- and 3.0-gram doses to humans in treatment of Escherichia coli bacteremia in mice. 778 98

In a molecular, microbiologic, and case-control study to describe the epidemiology of ceftazidime-resistant Klebsiella pneumoniae and Escherichia coli bloodstream infection, 32 unique isolates were recovered over 31 months from the blood of patients hospitalized in a 900-bed hospital in Chicago. Multivariate analysis revealed cases occurred more frequently in debilitated nursing home patients with central venous catheters than in younger, healthier patients. Mortality rates were similar for cases and controls. Case-patients were less likely to die if they received appropriate antibiotic treatment within 3 days of bacteremia onset (P = .02). Pulsed-field gel electrophoresis analysis indicated a polyclonal outbreak, with strain-specific temporal and geographic clustering. Isoelectric focusing results suggested that a predominant enzyme, TEM-10, was responsible for the ceftazidime resistance. The resistance gene was usually carried on a large conjugative plasmid. The polyclonality of the resistant strains suggests that ceftazidime resistance due to TEM-10 is now endemic in Chicago.
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PMID:Ceftazidime-resistant Klebsiella pneumoniae and Escherichia coli bloodstream infection: a case-control and molecular epidemiologic investigation. 876 10

An in vitro pharmacokinetic model (IVPM) and a mouse model of lethal bacteremia were used to compare the pharmacodynamics of ampicillin-sulbactam when the two components were dosed simultaneously and in sequence against TEM-1-producing Escherichia coli. The challenge isolates included three strains of E. coli producing various levels of beta-lactamase. Human pharmacokinetics of ampicillin-sulbactam (1.5- and 3.0-g intravenous doses) were simulated in each model, and pharmacodynamic interactions were evaluated over one 6-h dosing interval. Against all three strains, the sequential dosing of sulbactam prior to ampicillin did not alter the pharmacodynamics of these combinations from comparison with results obtained with the simultaneous administration of the two components. Similar pharmacodynamics were observed for the two dosing regimens regardless of the ampicillin-sulbactam dose used or whether the bacteria were treated in an immunocompetent mouse or in the absence of immune defenses in the IVPM. When antibacterial activity was lost and regrowth of the inoculum was observed, viable bacterial counts increased in both the simultaneous and sequential regimens at a point when sulbactam levels fell below a critical concentration. These data suggest that the efficacy of ampicillin-sulbactam is not dependent upon the maintenance of a constant 2:1 ratio for the two components. Rather, the efficacy of ampicillin-sulbactam appears to be dependent upon the maintenance of one or both components above a critical concentration. Furthermore, the pharmacokinetics of sulbactam, specifically, how long sulbactam levels remain above a minimum critical concentration, appears to dictate how long antibacterial activity is maintained with the combination.
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PMID:Efficacy of ampicillin-sulbactam is not dependent upon maintenance of a critical ratio between components: sulbactam pharmacokinetics in pharmacodynamic interactions. 891 48

Thirteen patients who had 16 episodes of bacteremia were observed between 1993 and 1997 in a pediatric oncology ward with a high background isolation rate of cefotaxime- or aztreonam-resistant gram-negative bacteria. Four blood isolates were Escherichia coli and 12 were Klebsiella pneumoniae, and these isolates harbored extended-spectrum beta-lactamases (ESBLs). All episodes of bacteremia were nosocomial, all except one of the episodes occurred in neutropenic patients, and all patients were treated with piperacillin or ceftazidime with amikacin and cefazolin prior to the onset of bacteremia. Nine of 13 patients were receiving extended-spectrum beta-lactam treatment when the bacteremias caused by ESBL producers occurred. Molecular studies revealed that four K. pneumoniae SHV-2-producing isolates from 1994 were of the same clone. Other ESBL producers, including six that carried both TEM-1 and SHV-5, five that carried SHV-5, and one that carried SHV-2 alone, were unrelated. In conclusion, SHV-5 was present in 11 of the 16 isolates and coexisted with TEM-1 in 6 isolates. Acquisition of resistance genes probably occurred under antibiotic selection pressure. This study highlights the importance of routine checks for and detection of ESBL producers. Effective therapy against ESBL producers should be considered early for children who have malignancies and neutropenia and who are septic, despite treatment with a regimen that includes an extended-spectrum beta-lactam, in a clinical setting of an increased incidence of ESBL-producing bacteria.
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PMID:Bacteremia due to extended-spectrum beta-lactamase-producing Escherichia coli and Klebsiella pneumoniae in a pediatric oncology ward: clinical features and identification of different plasmids carrying both SHV-5 and TEM-1 genes. 1056 24

To determine the epidemiologic features and clinical outcomes of bloodstream infections caused by extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli and Klebsiella pneumoniae isolates, cases of bacteremia caused by these organisms in children were analyzed retrospectively. Among the 157 blood isolates recovered from 1993 to 1998 at the Seoul National University Children's Hospital, the prevalence of ESBL production was 17.9% among the E. coli isolates and 52.9% among the K. pneumoniae isolates. The commonest ESBLs were SHV-2a and TEM-52. A novel ESBL, TEM-88, was identified. Pulsed-field gel electrophoresis analysis of the ESBL-producing organisms showed extensive diversity in clonality. The medical records of 142 episodes were reviewed. The risk factors for bloodstream infection with ESBL-producing organisms were prior hospitalization, prior use of oxyimino-cephalosporins, and admission to an intensive care unit within the previous month. There was no difference in clinical severity between patients infected with ESBL-producing strains (the ESBL group) and those infected with ESBL-nonproducing strains (the non-ESBL group) at the time of presentation. However, the overall fatality rate for the ESBL group was significantly higher than that for the non-ESBL group: 12 of 45 (26.7%) versus 5 of 87 (5.7%) (P = 0.001). In a subset analysis of patients treated with extended-spectrum cephalosporins with or without an aminoglycoside, favorable response rates were significantly higher in the non-ESBL group at the 3rd day (6 of 17 versus 33 of 51; P = 0.035), the 5th day (6 of 17 versus 36 of 50; P < 0.05), and the end of therapy (9 of 17 versus 47 of 50; P < 0.001). In conclusion, the ESBL production of the infecting organisms has a significant impact on the clinical course and survival of pediatric patients with bacteremia caused by E. coli and K. pneumoniae.
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PMID:Bloodstream infections by extended-spectrum beta-lactamase-producing Escherichia coli and Klebsiella pneumoniae in children: epidemiology and clinical outcome. 1195 86

The treatment outcome of 35 cases of bacteremia due to Klebsiella pneumoniae isolates producing TEM-52 extended-spectrum beta-lactamase was studied. Twenty-eight cases, classified as "nonfatal disease" using the McCabe and Jackson classification, were investigated with regard to ciprofloxacin and imipenem response. Because ciprofloxacin was active in vitro against 21 of 28 isolates, only the treatment outcome of the ciprofloxacin-susceptible subgroup was evaluated. Eight of 10 cases occurred in patients who experienced a complete response to imipenem; 2 of 10 failed to respond. In contrast, only 2 of 7 cases had a partial response to ciprofloxacin, and, in 5 of 7 cases, the treatment failed. Statistical analysis revealed a significant difference in the treatment outcome of the 2 groups (P=.03). Because the isolates had minimum inhibitory concentrations of ciprofloxacin close to the susceptibility breakpoint, treatment failure could be ascribed to the inability of the drug to reach therapeutic concentrations at infected sites.
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PMID:Bacteremia due to Klebsiella pneumoniae isolates producing the TEM-52 extended-spectrum beta-lactamase: treatment outcome of patients receiving imipenem or ciprofloxacin. 1469 57

Cases of bacteremia caused by AmpC-type-beta-lactamase-producing Klebsiella pneumoniae isolates were retrospectively studied to determine the epidemiologic features and clinical outcomes of bloodstream infections. Among 389 blood isolates recovered from 1998 to 2002, 65 isolates (16.7%) were found to be extended-spectrum beta-lactamase (ESBL) or AmpC beta-lactamase producers. The beta-lactamases from 61 of the 65 isolates were characterized; 28 of 61 isolates produced AmpC-type enzymes (14 isolates each produced DHA-1 and CMY-1-like enzymes), 32 isolates produced TEM or SHV-related ESBLs, and 1 isolate produced a CTX-M-14-like enzyme. To compare the clinical features and outcomes of bloodstream infections caused by AmpC producers with those caused by TEM- or SHV-related ESBL producers, 27 patients infected with isolates producing AmpC-type enzymes (AmpC group) and 25 patients infected with isolates producing TEM- or SHV-related enzymes (ESBL group) were analyzed. There was no significant difference between the AmpC and the ESBL groups in terms of risk factors. When the initial response was assessed at 72 h after antimicrobial therapy, the treatment failure rate for the AmpC group was 51.9% (14 of 27 patients) and the 7- and 30-day mortality rates were 14.8 and 29.6%, respectively, which were similar to those for the ESBL group. When the mortality rate for the patients who received extended-spectrum cephalosporins as definitive treatment was assessed, all four patients in the DHA-1 group and one of three patients in the CMY-1-like group died. In summary, the prevalence of AmpC enzyme-producing K. pneumoniae was high at the Seoul National University Hospital, and the clinical features and outcomes for the patients infected with AmpC-producing organisms were similar to those for the patients infected with TEM- or SHV-related ESBL producers.
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PMID:Epidemiology and clinical features of bloodstream infections caused by AmpC-type-beta-lactamase-producing Klebsiella pneumoniae. 1538 26

Enterobacter cloacae has been associated with several outbreaks, usually involving strains that overproduce chromosomal beta-lactamase or, uncommonly, strains expressing extended-spectrum beta-lactamases (ESBL). Only sporadic cases of ESBL-producing E. cloacae have been identified in our hospital in recent years. We describe the epidemiology and clinical and microbiological characteristics of an outbreak caused by ESBL-producing E. cloacae in a cardiothoracic intensive care unit (CT-ICU). Prospective surveillance of patients with infection or colonization by ESBL-producing E. cloacae among patients admitted to the CT-ICU was performed during the outbreak. Production of ESBL was determined by decreased susceptibility to expanded-spectrum cephalosporins and a positive double-disk test result. Clone relatedness was determined by pulsed-field gel electrophoresis (PFGE). From July to September 2005, seven patients in the CT-ICU with ESBL-producing E. cloacae were identified (four males; median age, 73 years; range, 45 to 76 years); six patients had cardiac surgery. Four patients developed infections; three had primary bacteremia, one had ventilator-associated pneumonia, and one had tracheobronchitis. ESBL-producing E. cloacae showed resistance to quinolones and aminoglycosides. PFGE revealed two patterns. Five isolates belonged to clone A; two carried a single ESBL (pI 8.2 and a positive PCR result for the SHV type), and three carried two ESBLs (pIs 8.1 and 8.2 and positive PCR results for the SHV and CTX-M-9 types). Isolates belonging to clone B carried a single ESBL (pI 5.4 and a positive PCR result for the TEM type). Review of antibiotic consumption showed increased use of cefepime and quinolones during June and July 2005. The outbreak was stopped by the implementation of barrier measures and cephalosporin restriction. ESBL production could be increasingly common in nosocomial pathogens other than Escherichia coli or Klebsiella pneumoniae.
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PMID:Nosocomial outbreak due to extended-spectrum-beta-lactamase- producing Enterobacter cloacae in a cardiothoracic intensive care unit. 1758 32

We report a relapsed case of a 25 year-old man with multi-drug resistant Salmonella serovar Typhi (MDRST) bacteremia who had recently returned from travel in India. Due to unresponsiveness to ciprofloxacin and ceftriaxone, we examined the strain's resistance to quinolones and extended-spectrum beta-lactamases (ESBLs). The strain had a single gyrA mutation at codon 83 (Ser83Phe), which explains its decreased susceptibility to fluoroquinolone and resistance to nalidixic acid. In the screening tests of ESBLs, TEM-1 was positive, which is beta-lactamase but not ESBL. The patient was finally successfully treated with meropenem and aztreonam. In the presence of clinical unresponsiveness despite favorable sensitivity tests, further laboratory evaluations are needed, which should include studies of genes related to antibiotic resistance and ESBLs. In addition, further prospective trials should be done about the possible inclusion of antibiotics not yet mentioned in the current guidelines. With MDRST on the rise worldwide, the most optimal and effective line of antibiotic defense needs to be devised.
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PMID:A case of multidrug-resistant Salmonella enterica serovar Typhi treated with a bench to bedside approach. 1925 62


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