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Biomedical subjects

V Korten

Publications and source records attributed to V Korten.

At least 19 recordsLinked to original sources
PubMed2003

Vancomycin versus placebo for treating persistent fever in patients with neutropenic cancer receiving piperacillin-tazobactam monotherapy.

This prospective, double-blind trial assessed whether the addition of a glycopeptide would be able to reduce the time to defervescence in neutropenic patients with cancer who had persistent fever 48-60 h after the initiation of empirical piperacillin-tazobactam monotherapy. Of 763 eligible patients, 165 with persistent fever were randomized to receive piperacillin-tazobactam therapy plus either vancomycin therapy or placebo. Defervescence was observed in 82 (95%) of 86 patients in the vancomycin group and in 73 (92%) of 79 patients in the placebo group (P=.52). The distributions of the time to defervescence were not statistically significant between the 2 groups (estimated hazard ratio, 1.03; 95% confidence interval, 0.75-1.43; P=.75). The number of additional episodes of gram-positive bacteremia and the percentage of patients for whom amphotericin B was empirically added to their therapy regimen were also similar in both groups. This study failed to demonstrate that the empirical addition of vancomycin therapy to the treatment regimen is of benefit to persistently febrile neutropenic patients with cancer.

Adolescent↗
PubMed2003

An unusual native tricuspid valve endocarditis caused by Candida colliculosa.

Candida colliculosa, which grew in blood cultures of a 71-year-old retired man with fever of unknown origin that had lasted for 7 months, in conjunction with transthoracic echocardiography, demonstrating a 20-mm vegetation, superior to the tricuspid valve, herniating into the right atrial cavity. The finding led to the diagnosis of fungal endocarditis. Fluconazole, 600 mg daily, was commenced for 8 days; followed by amphotericin B, 1 mg/kg daily. On the fourth day of the amphotericin B treatment, the patient underwent replacement of the infected tricuspid valve. Even though the initial postoperative period was relatively uncomplicated, the patient died after a gross aspiration on the 67th day of his hospital stay, despite aggressive cardiovascular support and antimicrobial therapy. This is the first report of a native tricuspid valve fungal endocarditis due to C. colliculosa or Torulaspora delbrueckii, which is not known to be a human pathogen.

Aged↗
PubMed2001

Comparison of cefepime and ceftazidime in combination with amikacin in the empirical treatment of high-risk patients with febrile neutropenia: a prospective, randomized, multicenter study.

A total of 208 adult patients with cancer and febrile neutropenia from 5 medical institutions were randomized to receive either cefepime (2 g b.i.d.) or ceftazidime (2 g t.i.d.) in combination with amikacin (15 mg/kg/o.d.). Ninety-seven patients in the ceftazidime (CEZ) group and 98 in the cefepime group (CEF) were evaluable for efficacy. In 68 patients (35%), infection could be documented. The average duration of antibiotic therapy was 11 and 12 d and response rates to the empirical regimen were 36 and 30% for the CEZ and CEF groups, respectively (p > 0.05). The average time of defervescence in responders was 3 d for both groups. Modification of the initial regimen with antivirals and/or azole antifungals raised the number of responders to 44% and 35%, respectively (p > 0.05). Vancomycin was additionally given to 29 patients in the CEZ group and to 27 patients in the CEF group. Twenty-six patients in each group received empirical amphotericin B. Mild, reversible study drug-related side-effects were observed in 12 patients (12%) in the CEZ group and 13 patients (13%) in the CEF group (p > 0.05). Cefepime in combination with amikacin seems to be as effective, safe and tolerable as ceftazidime + amikacin in patients with high-risk neutropenia and fever.

Adolescent↗
PubMed1999

Multicenter evaluation of the antimicrobial activity for seven broad-spectrum beta-lactams in Turkey using the Etest method. Turkish Antimicrobial Resistance Study Group.

From March through July 1997, a nine laboratory surveillance project was initiated in Turkey to monitor the potency and spectrum of seven broad-spectrum antimicrobial agents (cefepime, ceftazidime, cefotaxime, imipenem, aztreonam, cefoperazone/sulbactam, and ticarcillin/clavulanate) tested against approximately 100 organisms (average 82; range 70 to 95 isolates) per participant center (736 strains). Eleven groups of organisms were tested by the Etest method (AB BIODISK, Solna, Sweden) with results validated by concurrent quality control strain analysis. Results from all centers were tabulated and 91.1% of quality assurance tests were within ranges recommended by the National Committee for Clinical Laboratory Standards. Among the seven beta-lactam-class drugs tested, imipenem and cefepime were the most active beta-lactams tested against all isolates. Overall, the rank order of susceptibility of the seven agents was imipenem > cefepime > cefoperazone/sulbactam > ceftazidime > cefotaxime > aztreonam > ticarcillin/clavulanate. Both cefepime and imipenem were active against ceftazidime-resistant strains of Enterobacteriaceae as well as against Streptococcus spp. and oxacillin-susceptible Staphylococcus aureus. Resistance phenotypes consistent with extended spectrum beta-lactamases were documented among Escherichia coli and Klebsiella spp., and profiles consistent with stably derepressed Bush-Jacoby-Mederios group 1 (Amp C) cephalosporinases were common among Enterobacter spp., Citrobacter spp., and Serratia spp. These data should be used to guide empiric therapy with beta-lactams in Turkey, and additionally will provide a reference statistical baseline to which future national studies of drugs in this class can be compared.

Anti-Bacterial Agents↗
PubMed1999

Comparison of meropenem with amikacin plus ceftazidime in the empirical treatment of febrile neutropenia: a prospective randomised multicentre trial in patients without previous prophylactic antibiotics. Meropenem Study Group of Turkey.

Eighty three patients with neutropenia and cancer were randomised to receive either 1 g meropenem tds or amikacin 15 mg/kg single dose daily plus ceftazidime 2 g tds. No prophylactic antibiotics were allowed before entry to the trial. Seventy seven patients were available for analysis. Infection was microbiologically or clinically documented in 53 episodes (69%). The overall success rate without adjustment was 49% in monotherapy, 37.5% in the combination group. These rates were increased to 65% and 56%, respectively when secondary infection episodes requiring a different class of chemotherapy were taken into account. Median duration for defervescence was 3 days in successfully treated patients in both groups. Only minor reversible side effects were noted in both treatment arms. Meropenem monotherapy seemed as effective and safe as amikacin plus ceftazidime for the empirical treatment of neutropenic cancer patients with fever.

Adult↗
PubMed1999

Acute purulent exacerbation of chronic obstructive pulmonary disease and Chlamydia pneumoniae infection.

In order to investigate the role of bacteria, including Mycoplasma pneumoniae and especially Chlamydia pneumoniae in acute purulent exacerbations of chronic obstructive pulmonary disease (COPD), we examined sputum specimens and acute and convalescent sera taken 26 d apart from 49 outpatients experiencing an acute purulent exacerbation of COPD. The sera were tested for antibodies to C. pneumoniae with the microimmunofluorescence test, and for antibodies to M. pneumoniae with the indirect fluorescence antibody test. Routine microbiologic culture of sputum yielded potentially pathogenic microorganisms in 12 of the 49 patients (24%). Three patients (6%) showed serologic evidence of recent M. pneumoniae infection. Seven patients showed high IgG titers of >/= 1:1,024 to C. pneumoniae, and an additional four had a fourfold increase in IgG titer, suggesting reinfection with C. pneumoniae. Sputum from two of these 11 patients also grew Streptococcus pneumoniae, and one grew Moraxella catarrhalis. Patients with and without serologic evidence of current C. pneumoniae infection showed no significant differences in clinical features or pulmonary function. The high incidence of infection with C. pneumoniae (the sole causal agent in 16% of cases, and the causal agent with other agents in 6%) provides insight into the importance of this organism among agents leading to exacerbations of COPD in Turkey.

Aged↗
PubMed1996

Clostridium difficile acquisition rate and its role in nosocomial diarrhoea at a university hospital in Turkey.

Infection with Clostridium difficile can present with various clinical pictures ranging from an asymptomatic carrier state to pseudomembranous colitis and plays an important part in the etiology of nosocomial diarrhoea. To identify risk factors for C. difficile colonization and diarrhoea in hospitalized subjects, patients admitted to a general medicine ward at Marmara University hospital during a one year period were entered into the study. Of the 202 patients, nosocomial diarrhoea developed in 45 (22.3%). Fourteen patients (6.9%) were colonized with C. difficile during their hospitalization period. Ten of the colonized patients (71.4%) developed diarrhoea and were found to be positive by toxin assay. Pseudomembranous colitis was confirmed endoscopically in 3 of the patients with diarrhoea. Administration of beta lactam agents such as ampicillin and cephalosporins; gastrointestinal manipulations and admission to the intensive care unit were found as major risk factors for C. difficile colonization.

Adult↗
PubMed1996

Bactericidal activity of the fluoroquinolone DU-6859a alone and in combination with other antimicrobial agents against multiresistant enterococci.

The in vitro activity of DU-6859a (DU) alone and in combination with various antimicrobials was evaluated against multiresistant enterococci including some isolates with defined gyrA mutations. DU produced rapid in vitro killing against most enterococci that lacked resistance to ciprofloxacin, but it was not bactericidal against strains with MICs of ciprofloxacin of > or = 8 micrograms/ml, or against one of four strains with an MIC of ciprofloxacin of 4 micrograms/ml. The combination of DU with rifampin was antagonistic against two of two isolates tested. Combinations of DU and novobiocin, gentamicin, or a beta-lactam (amoxicillin, ampicillin-sulbactam, or amoxicillin-clavulanate) were generally indifferent. When different beta-lactams were used together, with or without DU, bactericidal activity was observed against some isolates. Despite the absence of synergistic interactions with other agents, DU is a promising fluoroquinolone for use against enterococci, although prior development of resistance to currently available fluoroquinolones diminishes some of its effect.

Anti-Bacterial Agents↗
PubMed1996

Influence of oral glycopeptides on the fecal flora of human volunteers: selection of highly glycopeptide-resistant enterococci.

Changes in fecal flora were evaluated in 22 healthy volunteers administered oral vancomycin or teicoplanin in 1989-1991 in Belgium. Evaluation of 5 colonies per subject revealed no glycopeptide-resistant enterococci in the predominant flora before glycopeptide administration; however, large numbers (mostly Enterococcus faecium) emerged by the end of the study in 14 (64%) of the subjects. Pediococci and lactobacilli also increased in number. In 1992, 40 healthy volunteers and 33 cancer patients were evaluated by plating stool samples directly onto selective media containing vancomycin; low numbers of vancomycin-resistant enterococci (< 50 cfu/g) were found in 11 (28%) of the 40 and 4 (12%) of the 33 samples, respectively. DNA restriction fragment length polymorphism analysis showed that most isolates were different, but all contained vanA in Tn1546-like elements. These results indicate that vanA and Tn1546-like elements were common in Belgium as early as 1989 and that community-based individuals in that location likely form a major reservoir for glycopeptide-resistant enterococci.

Adult↗
PubMed1995

Antimicrobial prophylaxis in management of urinary tract stones by extracorporeal shock-wave lithotripsy: is it necessary?

OBJECTIVES: In a prospective randomized study, we evaluated the incidence of urinary tract infections following extracorporeal shock-wave lithotripsy (ESWL) and the necessity of prophylactic antibiotic administration in patients treated with this modality. METHODS: A total of 360 consecutive patients with renal and ureteric stones who had sterile urine before ESWL treatment and did not have any increased risk of infection received either a single dose of 400 mg of ofloxacin or no prophylaxis. Patients were followed by simple urine analysis and urine cultures together, with clinical evaluations. RESULTS: Only 3 patients (0.8%) had positive urine cultures at 1 week after ESWL. Two of these patients were in the antibiotic prophylaxis group. CONCLUSIONS: The incidence of urinary tract infections after ESWL is extremely low, provided that patients have sterile urine before ESWL, and prophylactic antibiotics are not required.

Adult↗
PubMed1994

DU-6859a, a new fluoroquinolone agent. Comparative in vitro activity against enteric pathogens and multiresistant outpatient Escherichia coli.

The activity of DU-6859a, a new fluoroquinolone antimicrobial agent, was compared with that of ciprofloxacin by agar dilution susceptibility testing against enteric pathogens and multiresistant Escherichia coli. The results indicate that DU-6859a inhibits most of these organisms at concentrations similar to those of ciprofloxacin. DU-6859a showed increased activity compared to ciprofloxacin against Campylobacter species isolates.

Anti-Infective Agents↗
PubMed1994

Comparative in vitro activity of DU-6859a, a new fluoroquinolone agent, against gram-positive cocci.

The in vitro activity of DU-6859a (DU), a new fluoroquinolone agent, was evaluated against 233 gram-positive cocci and was compared with those of ciprofloxacin, vancomycin, nafcillin, and ampicillin. The MICs of DU for 90% of the staphylococci tested were < or = 0.06 microgram/ml. All of the groups A and B and viridans group streptococci were inhibited by < or = 0.125 microgram of DU per ml, which was 32-fold more active than ciprofloxacin. On the basis of MICs for 90% of the strains tested, DU was 32- and 16-fold more active than ciprofloxacin against Enterococcus faecalis and Enterococcus faecium, respectively. The bactericidal activity of DU was demonstrated by time-kill techniques against all ciprofloxacin-susceptible enterococci. DU shows promise for the treatment of infections with gram-positive cocci and warrants further evaluation by in vitro and in vivo studies.

Anti-Bacterial Agents↗
PubMed1994

Analysis by PCR and direct DNA sequencing of gyrA mutations associated with fluoroquinolone resistance in Enterococcus faecalis.

A region of gyrA, the gene encoding subunit A of DNA gyrase, that is known to be associated with resistance was amplified and sequenced from 16 Enterococcus faecalis and Enterococcus faecium isolates. Six ciprofloxacin-resistant clinical isolates (MICs of ciprofloxacin, 32 to 64 micrograms/ml) and one multistep resistant laboratory mutant of E. faecalis (MIC of ciprofloxacin, 128 micrograms/ml) contained a change from serine to arginine or to isoleucine at codon 83 or a change from glutamic acid to lysine or to glycine at codon 87 (Escherichia coli GyrA coordinates); these changes have been associated with fluoroquinolone resistance in other species. No difference in the region studied was found in two ciprofloxacin-resistant E. faecium isolates (MICs, 32 micrograms/ml) or in four laboratory derived, spontaneous ciprofloxacin-resistant mutants of E. faecalis (MICs, 8 to 16 micrograms/ml), suggesting that other mechanisms may be responsible for fluoroquinolone resistance in some enterococci.

Amino Acid Sequence↗
PubMed1993

Treatment of intracranial abscesses: experience with sulbactam/ampicillin.

In an open prospective study, the efficacy of sulbactam/ampicillin (50 and 100 mg/kg, respectively, qid) was evaluated in 21 patients with intracranial abscess(es). Sixteen patients had cerebral, 3 epidural, and 2 cerebellar abscesses. Multiple lesions were found in 7 patients. Sixteen patients underwent surgical intervention, others were treated with antibiotic alone. The mean duration of antibiotic therapy (+/- SD) was 48 +/- 10 days (range 26-65 days). The mean duration of follow-up after completion of therapy (+/- SD) was 6 +/- 2.4 months. All patients had at least some reduction in size of abscess(es) within 3 weeks of the initiation of therapy as monitored by computerized tomography. Seventeen patients were cured, three patients died due to causes unrelated to their infection. One patient was reoperated since no clear improvement either clinically or radiologically was observed 18 days after the first operation. Side effects of sulbactam/ampicillin were minor and transient. Results obtained in this study indicate that sulbactam/ampicillin can be used in the treatment of intracranial abscesses, alone or with surgical intervention.

Adolescent↗
PubMed1993

Impact of the fluoroquinolones on gastrointestinal flora.

A number of studies have been performed to evaluate the effect of the fluoroquinolones on gastrointestinal flora. The fluoroquinolones have only slight or no effect on the oropharyngeal flora, except when Neisseria, Haemophilus or Branhamella spp. are present. Studies have consistently shown that Gram-negative facultative bacteria of the lower intestinal flora are strongly suppressed during administration of these agents. Total faecal anaerobes are generally unchanged. The effect of the fluoroquinolones on Gram-positive bacteria is more variable with mild to moderate suppression reported with some agents. In view of the high faecal concentrations of the fluoroquinolones, the general lack of effect on anaerobes is surprising; it may be attributable to the large number of microorganisms found in faeces and faecal binding of the fluoroquinolones. Several recent studies suggest that the effects of some fluoroquinolones on faecal anaerobes and Gram-positive cocci may be more profound in certain patient populations such as bone marrow transplant recipients and patients undergoing gastrointestinal surgery. Colonisation with yeasts and the emergence of resistant bacterial strains have been reported during or after fluoroquinolone administration in some studies. Future studies will need to investigate the effect of the newer agents with greater activity against anaerobes and Gram-positive cocci on the gastrointestinal flora and to continue surveillance for resistant organisms.

Anti-Infective Agents↗