Comparison Of Microdilution And Disk Diffusion Methods For The Detection Of Fluconazole And Voriconazole Susceptibility Against Clinical Candida Glabrata Isolates And Determination Of Changing Susceptibility With New Clsi Breakpoints

Candida albicans is the most frequently isolated species as the causative agent of Candida infections. However, in recent years, the isolation rate of non-albicans Candida species have increased. In many centers, Candida glabrata is one of the commonly isolated non-albicans species of C.glabrata infections which are difficult-to-treat due to decreased susceptibility to fluconazole and cross-resistance to other azoles. The aims of this study were to determine the in vitro susceptibility profiles of clinical C.glabrata isolates against fluconazole and voriconazole by microdilution and disk diffusion methods and to evaluate the results with both the previous (CLSI) and current species-specific CLSI (Clinical and Laboratory Standards Institute) clinical breakpoints. A total of 70 C.glabrata strains isolated from clinical samples were included in the study. The identification of the isolates was performed by morphologic examination on cornmeal Tween 80 agar and assimilation profiles obtained by using ID32C (BioMerieux, France). Broth microdilution and disk diffusion methods were performed according to CLSI M27-A3 and CLSI M44-A2 documents, respectively. The results were evaluated according to CLSI M27-A3 and M44-A2 documents and new vs. species-specific CLSI breakpoints. By using both previous and new CLSI breakpoints, broth microdilution test results showed that voriconazole has greater in vitro activity than fluconazole against C.glabrata isolates. For the two drugs tested, very major error was not observed with disk diffusion method when microdilution method was considered as the reference method. Since "susceptible" category no more exists for fluconazole vs. C.glabrata, the isolates that were interpreted as susceptible by previous breakpoints were evaluated as susceptible-dose dependent by current CLSI breakpoints. Since species-specific breakpoints remain yet undetermined for voriconazole, comparative analysis was not possible for this agent. The results obtained at 24 hours by disk diffusion method were evaluated by using both previous and current CLSI breakpoints and the agreement rates for fluconazole and voriconazole were 80% and 92.8% with previous CLSI breakpoint, 87.1% and 94.2% with new breakpoints, respectively. The high agreement rates between the two methods obtained by the new breakpoints in particular suggest that disk diffusion appears as a reliable alternative method in general for in vitro susceptibility testing of fluconazole and voriconazole against C.glabrata isolates.WoSScopu

First pediatric case of osteomyelitis caused by Robinsoniella peoriensis

Robinsoniella peoriensis is a gram-positive, spore-forming, anaerobic rod. In our study, we isolated It peoriensis from an open fracture of the left distal tibia of a three-year-old male patient. Tissue anaerobic culture was positive for R. peoriensis. It was identified with both matrix-assisted laser desorption ionization time-of-flight mass spectrometry and confirmed via 16S rRNA gene sequencing. The patient responded to ampicillin-sulbactam and amikacin antibiotic therapy. Antimicrobial susceptibility testing should be performed to guide the choice of treatment. To the best of our knowledge, this is the first report of R. peoriensis osteomyelitis in a pediatric patient and first report from Turkey

Head-To-Head Comparison Of Inhibitory And Fungicidal Activities Of Fluconazole, Itraconazole, Voriconazole, Posaconazole, And Isavuconazole Against Clinical Isolates Of Trichosporon Asahii

Treatment of disseminated Trichosporon infections still remains difficult. Amphotericin B frequently displays inadequate fungicidal activity and echinocandins have no meaningful antifungal effect against this genus. Triazoles are currently the drugs of choice for the treatment of Trichosporon infections. This study evaluates the inhibitory and fungicidal activities of five triazoles against 90 clinical isolates of Trichosporon asahii. MICs (mu g/ml) were determined according to Clinical and Laboratory Standards Institute microdilution method M27-A3 at 24 and 48 h using two endpoints, MIC-2 and MIC-0 (the lowest concentrations that inhibited similar to 50 and 100% of growth, respectively). Minimum fungicidal concentrations (MFCs; mu g/ml) were determined by seeding 100 mu l of all clear MIC wells (using an inoculum of 104 CFU/ml) onto Sabouraud dextrose agar. Time-kill curves were assayed against four clinical T. asahii isolates and the T. asahii ATCC 201110 strain. The MIC-2 (similar to 50% reduction in turbidity compared to the growth control well)/MIC-0 (complete inhibition of growth)/MFC values that inhibited 90% of isolates at 48 h were, respectively, 8/32/64 mu g/ml for fluconazole, 1/2/8 mu g/ml for itraconazole, 0.12/0.5/2 mu g/ml for voriconazole, 0.5/2/4 mu g/ml for posaconazole, and 0.25/1/4 mu g/ml for isavuconazole. The MIC-0 endpoints yielded more consistent MIC results, which remained mostly unchanged when extending the incubation to 48 h (98 to 100% agreement with 24-h values) and are easier to interpret. Based on the time-kill experiments, none of the drugs reached the fungicidal endpoint (99.9% killing), killing activity being shown but at concentrations not reached in serum. Statistical analysis revealed that killing rates are dose and antifungal dependent. The lowest concentration at which killing activity begins was for voriconazole, and the highest was for fluconazole. These results suggest that azoles display fungistatic activity and lack fungicidal effect against T. asahii. By rank order, the most active triazole is voriconazole, followed by itraconazole similar to posaconazole similar to isavuconazole > fluconazole.WoSScopu

An unusual case of peritoneal dialysis-associated bacterial peritonitis caused by Weeksella virosa

Weeksella virosa is an atypical Gram-negative bacterium that does not grow on MacConkey agar. In this report, we present a 4-year-old female patient with Addison's disease and end-stage renal failure secondary to focal sclerosing glomerulosclerosis. Continuous ambulatory peritoneal dialysis had been performed, and 3 months later, the patient developed fever, diarrhea, and vomiting. Peritoneal fluid culture and dialysis fluid culture were positive for W. virosa. It was identified with Phoenix (BD, USA) and confirmed via 16S rRNA sequencing. It cannot be identified by Maldi Biotyper (Bruker). The isolate was found to be resistant to cephalosporins, ciprofloxacin, and amikacin by gradient test. Intraperitoneal cefepime was initiated but since antimicrobial susceptibility testing revealed cephalosporin resistance, therapy was changed to intraperitoneal meropenem. Following the removal of peritoneal dialysis catheter, fever, abdominal distention, and vomiting were resolved. Piperacillin, aztreonam, and carbapenems can be used for empirical therapy. Antimicrobial susceptibility testing should be performed to guide the choice of treatment. Removal of peritoneal dialysis catheter is an important step of management of this infection. To our knowledge, this is the first report of W. virosa in a pediatric patient and first report from Turkey

Aspergillus And Nocardia Coinfection In A Patient With Allogeneic Stem Cell Transplantation

In this report, we present a rare case of Aspergillus and Nocardia coinfection in a patient who underwent extensive immunosuppressive treatment due to graft versus host disease after allogeneic stem cell transplantation. We would like to emphasize the effect of targeted treatment on patient survival, and importance of collaboration between clinicians and laboratory professionals in providing early diagnosis even in rare infections.WoSScopu