Clindamycin plus gentamicin as expectant therapy for presumed mixed infections.
(1/1262)
The prevalence of obligate anaerobes was studied prospectively in 60 patients with severe sepsis of intra-abdominal, soft tissue, female genital or oropulmonary origin. In addition, the efficacy of clindamycin (for anaerobes) plus gentamicin (for aerobic bacteria, especially coliforms) as initial empiric therapy in these patients was evaluated. Among 54 patients with cultural proof of infection, anaerobic pathogens were recovered from 52%. Nineteen patients had bacteremia; Bacteroides fragilis and Klebsiella pneumoniae were the most prevalent pathogens, being isolated in five patients each. Infection was eradicated in 56 of the 60 patients (93%). Mortality related to sepsis was 7% in the entire group, 16% in patients with bacteremia and 2% in patients without bacteremia. Eighty-five percent of aerobic isolates tested were susceptible in vitro to either gentamicin or clindamycin; 97% of anaerobic isolates were inhibited by 5 mug/ml of clindamycin. (+info)
In-vitro selection of porin-deficient mutants of two strains of Klebsiella pneumoniae with reduced susceptibilities to meropenem, but not to imipenem.
(2/1262)
We have evaluated the ability of imipenem and meropenem to select, in vitro, resistant mutants of two clinical isolates of Klebsiella pneumoniae producing both SHV and TEM beta-lactamases. Only meropenem selected mutants of both isolates for which the MICs of meropenem, but not imipenem, were markedly higher than those for the parent strains; the MICs of several other beta-lactam antibiotics, including beta-lactam/beta-lactamase inhibitor combinations, for these mutants were also higher than those for the parent strains. In contrast, the MICs for the imipenem-selected mutants were the same as, or similar to, those for the parent strains. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis analysis revealed that an outer membrane protein in both parent strains was absent in the meropenem-selected mutants, but not in the imipenem-selected mutants. This protein is likely to be a porin, the absence of which is presumably associated with impaired beta-lactam permeability and, therefore, the reduced susceptibilities to these antibiotics exhibited by the mutant strains. We believe that this is the first report of the in-vitro selection of porin-deficient mutants of K. pneumoniae following exposure to meropenem. (+info)
Apolipoprotein E knock-out mice are highly susceptible to endotoxemia and Klebsiella pneumoniae infection.
(3/1262)
Lipoproteins are able to neutralize bacterial lipopolysaccharide (LPS) and thereby inhibit the proinflammatory cytokine response. In a previous study, we demonstrated that hypercholesterolemic low density lipoprotein receptor knock-out (LDLr-/-) mice are protected against lethal endotoxemia and gram-negative infection. In the present study we investigated the susceptibility of apolipoprotein E knock-out mice (apoE-/-) to LPS and to Klebsiella pneumoniae. These mice have increased plasma lipoprotein concentrations in the very low density lipoprotein (VLDL)-sized fraction. Despite 8 -fold higher plasma cholesterol levels compared to controls, and in contrast to LDLr-/- mice, apoE-/- mice were significantly more susceptible to endotoxemia and to K. pneumoniae infection. Circulating TNFalpha concentrations after intravenously injected LPS were 4 - to 5-fold higher in apoE-/- mice, whereas IL-1alpha, IL-1beta, and IL-6 did not differ. This TNF response was not due to an increased cytokine production capacity of cells from apoE-/- mice, as ex vivo cytokine production in response to LPS did not differ between apoE-/- and control mice. The LPS-neutralizing capacity of apoE-/- plasma was significantly less than that of controls. Most likely, the absence of apoE itself in the knock-out mice explains the failure to neutralize LPS, despite the very high cholesterol concentrations. (+info)
Short-course ceftriaxone therapy in spontaneous bacterial peritonitis.
(4/1262)
Forty patients with spontaneous bacterial peritonitis, three of whom had complicating acute hepatitis syndrome, eight late-onset hepatic failure, and 29 with cirrhosis, were treated with ceftriaxone 2 g intravenously once daily for 5 days. Ascitic fluid culture was positive in 28 patients, with Escherichia coli and Klebsiella as common isolates. All the bacteria isolated were sensitive to ceftriaxone except Enterococcus faecalis, which was isolated in a cirrhotic patient. All culture-positive patients sensitive to ceftriaxone showed bacteriological cure and 26 (65%) patients showed cytological cure after 48 hours of treatment. A total of 95% were cured of their infection after 5 days of treatment. Twelve (30%) patients died during hospitalisation after documented cure of their spontaneous bacterial peritonitis (renal failure, gastrointestinal bleed and cerebral oedema were the primary causes of death). Infection-related mortality due to Pseudomonas septicaemia was seen in one cirrhotic patient. (+info)
Porin expression in clinical isolates of Klebsiella pneumoniae.
(5/1262)
Two porins, OmpK36 and OmpK35, have been described previously in Klebsiella pneumoniae, and they are homologous to the Escherichia coli porins OmpC and OmpF, respectively, at both the DNA and amino acid levels. Optimal resolution of the two K. pneumoniae porins by electrophoresis on polyacrylamide gels is not achieved using gel systems already described for E. coli and requires modifications of the bisacrylamide content of the resolving gels. Once resolved, identification of porins OmpK36 and OmpK35 cannot be based solely on their apparent molecular masses since in some strains the OmpK36 porin migrates faster than the OmpK35 porin, whilst in other strains OmpK35 is the faster-migrating porin. Expression of OmpK35 porin is increased in low-osmolarity medium and, combined with Western blot analysis, this allows for the identification of both porins. Application of this identification system showed that most isolates lacking expression of extended-spectrum beta-lactamases express the two porins, whereas most isolates producing these beta-lactamases express only porin OmpK36, and the OmpK35 porin is either very low or not expressed. (+info)
Genetic characterization of resistance to extended-spectrum beta-lactams in Klebsiella oxytoca isolates recovered from patients with septicemia at hospitals in the Stockholm area.
(6/1262)
Two beta-lactamase gene regions were characterized by DNA sequencing in eight clinical isolates of Klebsiella oxytoca. The blaOXY-2a region encoded a beta-lactamase nearly identical to OXY-2 (one amino acid residue substituted) and conferred aztreonam and cefuroxime resistance on the K. oxytoca isolates. Overproduction of OXY-2a was caused by a G-to-A substitution of the fifth nucleotide in the -10 consensus sequence of blaOXY-2a. The blaOXY-1a was identified in a susceptible strain, and the OXY-1a enzyme differed from OXY-1 by two amino acid residues. (+info)
Survey of extended-spectrum beta-lactamases in clinical isolates of Escherichia coli and Klebsiella pneumoniae: prevalence of TEM-52 in Korea.
(7/1262)
Two hundred ninety isolates of Escherichia coli were investigated for the production of extended-spectrum beta-lactamases (ESBLs). Fourteen (4.8%) of the 290 strains were found to produce ESBLs. Each of the 14 strains produced one or two ESBLs, as follows: 10 strains produced TEM-52, 1 strain produced SHV-2a, 1 strain produced SHV-12, 1 strain produced a CMY-1-like enzyme, and 1 strain expressed SHV-2a and a CMY-1-like enzyme. Another two strains for which the MICs of ceftazidime and cefoxitin were high, were probable AmpC enzyme hyperproducers. Because of the high prevalence of TEM-52 in E. coli isolates, we further investigated the TEM-type ESBLs produced by Klebsiella pneumoniae in order to observe the distribution of TEM-52 enzymes among Enterobacteriaceae in Korea. All TEM enzymes produced by 12 strains of K. pneumoniae were identified as TEM-52. To evaluate the genetic relatedness among the organisms, ribotyping of TEM-52-producing E. coli and K. pneumoniae was performed. The ribotyping profiles of the organisms showed similar but clearly different patterns. In conclusion, TEM-52 is the most prevalent TEM-type ESBL in Korea. (+info)
Outbreak of extended spectrum beta lactamase producing Klebsiella pneumoniae in a neonatal unit.
(8/1262)
An outbreak of extended spectrum beta lactamase producing Klebsiella pneumoniae (ESBLKp) in a neonatal unit was controlled using simple measures. Normally, the control of such infections can be time consuming and expensive. Seven cases of septicaemia resulted in two deaths. ESBLKp isolates were subtyped by pulsed field gel electrophoresis, and four of the five isolates typed were identical. Control of the outbreak was achieved by altered empiric antibiotic treatment for late onset sepsis and prevention of cross infection by strict attention to hand washing. Widespread colonisation of babies in the unit was presumed, so initial surveillance cultures were not performed. No further episodes of sepsis occurred. (+info)