MATERIALS AND METHODS: Febrile neutropenic patients treated between January 1996 and December 1997 at the pediatric oncology unit of University Hospital, Kuala Lumpur, were prospectively studied. Empirical antibiotic therapy consisted of ceftazidime and amikacin. Those who developed K. pneumoniae bacteremia were identified, and clinical features analyzed. Ceftazidime-resistance was documented via disk-diffusion testing. Production of extended-spectrum beta-lactamase (ESBL) was inferred on the basis of synergy between ceftazidime and amoxicillin-clavulanic acid. The different features between the two groups and variables associated with the development of CRKP bacteremia were analyzed using chi-square and t-tests and calculation of odds ratios. A multivariate analysis was used to identify independent factors for CRKP development.
RESULTS: Ceftazidime-resistance was seen in 51.6% of all K. pneumoniae isolates, and all these isolates were inferred to be ESBL producers. All isolates were sensitive to imipenem. Susceptibility to gentamicin was 90.5%. The mean continuous hospital stay prior to the detection of bacteremia was 13.7 days overall, but significantly longer in the CRKP group (21.9 d) compared to the CSKP group (4.3 d) (P = 0.003). Children with CRKP were more likely to have received antibiotics in the 2 weeks prior to detection of bacteremia (87.5% of cases) than the CSKP group (20.0% of cases) (P = 0.0008). Sepsis-related mortality was higher in those with CRKP (50.0%) than in the CSKP group (13.3%) (P = 0.02). Patients who did not receive CRKP-directed antibiotics within 48 hours of admission were more likely to have a fatal outcome than those who did (P = 0.009). Logistic regression analysis identified use of third-generation cephalosporins 2 weeks prior to presentation and a hospital stay of 2 weeks or more as independent risk factors for development of CRKP.
CONCLUSIONS: More than half of total K. pneumoniae isolated from blood cultures in the unit were ceftazidime-resistant. Children with febrile neutropenia with prolonged hospital stay and recent prior antibiotic exposure are at high risk of developing CRKP bacteremia. Mortality was significantly higher in this group. Early commencement of appropriate antibiotics (e.g., imipenem with or without gentamicin), according to susceptibility study results, may be beneficial in such circumstances.
METHODOLOGY: One hundred and ninety-one episodes of fever and neutropenia in 128 patients from October 1997 to December 1998 were included in a prospective, open-label, single-centre study. Patients were randomly assigned to either treatment group and evaluated as successes or failures according to defined criteria. Daily assessments were made on all patients and all adverse events recorded. Univariate and multivariate analysis of outcomes and a cost analysis were carried out.
RESULTS: There were 176 evaluable patient-episodes with 51.1% in the single-daily ceftriaxone-amikacin group and 48.9% in the ceftazidime-amikacin group. There were 50 positive blood cultures: 12 Gram-positive bacteria, 33 Gram-negative bacteria and five fungi. Pseudomonas aeruginosa (P. aeruginosa) accounted for 14% of total isolates. The overall success rate was 55.5% in the ceftriaxone group compared to 51.2% in the ceftazidime group (P = 0.56). Mean time to defervescence was 4.2 days in the single-daily group and 4.3 days in the thrice-daily group. There were nine infection-related deaths; five in the single-daily ceftriaxone group. The daily cost of the once-daily regime was 42 Malaysian Ringgit less than the thrice-daily regime. There was a low incidence of adverse effects in both groups, although ototoxicity was not evaluable.
CONCLUSIONS: The once-daily regime of ceftriaxone plus amikacin was as effective as the 'standard' combination of thrice-daily ceftazidime and amikacin with no significant adverse effects in either group. The convenience and substantial cost benefit of the once-daily regime will be particularly useful in developing countries with limited health resources and in centres with a low prevalence of P. aeruginosa.