Evaluation of a new chromogenic medium, chromID OXA-48, for recovery of carbapenemase-producing Enterobacteriaceae from patients at a university hospital in Turkey

The purpose of this study was to evaluate a new chromogenic medium, chromID OXA-48, for the isolation of carbapenemase-producing Enterobacteriaceae (CPE) directly from rectal swabs. chromID CARBA and chromID OXA-48 are two chromogenic media that have been commercialized for the isolation of CPE directly from clinical samples. Both media were evaluated alongside a broth enrichment method recommended by the CDC for isolation of CPE, with rectal swabs from 302 unique hospitalized patients at the Hacettepe University Hospital, Ankara, Turkey. A total of 33 patients (11 %) were found to be colonized with CPE using a combination of all methods, and all CPE produced OXA-48 carbapenemase. Klebsiella pneumoniae was by far the most dominant species of CPE and was isolated from 31 patients. Culture on chromID OXA-48 offered the highest sensitivity (75.8 %) for detection of CPE compared with the other two methods (sensitivity for both other methods was 57.6 %) and also offered the highest specificity (99.3 %). However, a combination of methods (either chromID OXA-48 plus CDC method or chromID OXA-48 plus chromID CARBA) was necessary to achieve an acceptable sensitivity (90.9 %). For isolation of CPE, in a setting where OXA-48 carbapenemase is the dominant type of carbapenemase, chromID OXA-48 is a highly useful medium but using a combination of methods is optimal for adequate detection. The combined use of two chromogenic media offered acceptable sensitivity (90.9 %) and the highest specificity (98.5 %) and also allowed for isolation of CPE within 18-20 h.

Diarrhea in neutropenic patients: a prospective cohort study with emphasis on neutropenic enterocolitis

BACKGROUND

Although diarrhea is a frequent complication in neutropenic patients, its true incidence, risk factors and clinical course have not been investigated prospectively.

PATIENTS AND METHODS

The study was carried out at Hacettepe University Hospital for Adults and involved patients over 16 years of age. Patients with malignant diseases who were neutropenic on admission or who became neutropenic during their stay in the wards between January 2001 and February 2003 were included. They were monitored daily until discharge, exitus, or recovery from neutropenia-whichever occurred earlier-to monitor the presence of diarrhea and other infections.

RESULTS

A total of 317 neutropenic episodes in 215 patients were followed. Diarrhea was observed in 18.6% episodes, and the incidence of NEC was 3.5%. The etiology in 27% episodes of diarrhea could not be identified. The use of anthracyclines and mitoxantrone increased the incidence of diarrhea. Prior use of penicillin derivatives plus beta-lactam inhibitors and N-imidazoline derivatives was associated with decreased incidence of diarrhea.

CONCLUSIONS

Diarrhea is a common complication in neutropenic patients. Not only specific conditions like NEC, but also nonspecific diseases like parasitosis may be the cause of diarrhea in this patient population.

Rapid detection of antibacterial resistance in emerging Gram-positive cocci

Effective infection control efforts obviously depend on the performance of the laboratory to detect emerging resistant pathogens accurately and confirm resistance patterns by additional methods to conventional or automated systems. Conventional methods still remain the predominant approaches for detection and identification of bacteria and resistance patterns. However, the estimated time for conventional tests to detect resistance is at least 24-48 h for methicillin-resistant Staphylococcus aureus, vancomycin-resistant enterococci and other epidemiologically important pathogens. Most of the tests used for rapid detection require bacterial growth in culture. There is an important clinical need for rapid detection of bacteria directly from patient samples. Rapid methods based on immunological or molecular technologies have contributed significantly. Molecular assays for several resistance markers are reliable, such as for mecA in staphylococci and vanA in enterococci. However, for other resistance markers, there is a lack of field testing. Cost-effectiveness of rapid detection of antibacterial resistance is another concern. Molecular assays would be useful for tertiary hospitals considering the investment costs and requirement of expert laboratory staff. For smaller centres, rapid tests based on immunological techniques may be a better choice.

Pregnancy complicated by Evan's syndrome

Evan's syndrome was initially diagnosed in a 26-year-old pregnant patient. Following the introduction of high dose steroid therapy, the patient developed possible disseminated gonococcal infection which was followed by preterm labor and abruptio placentae. A cesarean delivery was performed at the 34th week of pregnancy following platelet infusion. While the infant survived, the mother had delayed postpartum hemorrhage.

[The effect of the inoculum concentration on the in vitro sensitivity of Pseudomonas aeruginosa]

Using a broth microtiter dilution method, the minimum inhibitory concentrations of antipseudomonal antibiotics were determined against 19 P. aeruginosa isolates. Two different concentration of inoculum, 10(5) and 10(8), were used to show the inoculum concentration effect of in vitro antibiotic susceptibility tests. On the basis of the MIC values and using Howard B.J. (1) breakpoints, the effect of inoculum density was most prominent for amikacin and aztreonam, intermediate for mezlocillin, ticarcillin, piperacillin, cefotaxime, cefoperazone, netilmicin, tobramycin, gentamicin, and least apparent for ciprofloxacin and carbenicillin respectively.