Deml, Sharon M.

ABSTRACT We describe a case of chronic tenosynovitis in the hand of a 58-year-old cattle farmer. Surgical biopsy specimens grew Mycobacterium arupense . The patient responded to surgery and antimicrobial therapy based on in vitro susceptibility testing. The antimicrobial susceptibility profiles of the isolate from this patient and 39 additional clinical isolates are presented.

ABSTRACT The Yeast Traffic Light PNA FISH kit (YTL) correctly identified Candida spp. in 207/216 (96%) positive blood cultures. Discordant results were seen with known cross-reacting species and cultures containing Candida lambica and Rhodotorula mucilaginosa . The YTL provides rapid, reliable identification of the five common Candida species found in blood cultures.

ABSTRACT Antimicrobial susceptibility testing (AST) of clinical isolates of Nocardia is recommended to detect resistance to commonly used antimicrobial agents; such testing is complicated by difficulties in inoculum preparation and test interpretation. In this study, six laboratories performed repetitive broth microdilution testing on single strains of Nocardia brasiliensis , Nocardia cyriacigeorgica , Nocardia farcinica , Nocardia nova , and Nocardia wallacei . For each isolate, a total of 30 microdilution panels from three different lots were tested at most sites. The goal of the study was to determine the inter- and intralaboratory reproducibility of susceptibility testing of this group of isolates. Acceptable agreement (>90% agreement at ±1 dilution of the MIC mode) was found for amikacin, ciprofloxacin, clarithromycin, and moxifloxacin. After eliminating MIC values from single laboratories whose results showed the greatest deviation from those of the remaining laboratories, acceptable agreement was also found for amoxicillin-clavulanic acid, linezolid, minocycline, and tobramycin. Results showed unsatisfactory reproducibility of broth microdilution testing of ceftriaxone with N. cyriacigeorgica and N. wallacei , tigecycline with N. brasiliensis and N. cyriacigeorgica , and sulfonamides with N. farcinica and N. wallacei. N. nova ATCC BAA-2227 is proposed as a quality control organism for AST of Nocardia sp., and the use of a disk diffusion test for sulfisoxazole is proposed as a check of the adequacy of the inoculum and to confirm sulfonamide MIC results.

ABSTRACT The SLOMYCO Sensititre panel and the custom JustOne strip (both from TREK Diagnostic Systems, Cleveland, OH) were evaluated for susceptibility testing of Mycobacterium avium complex isolates against clarithromycin. Seventy-one archived and prospectively collected isolates were tested using both the SLOMYCO panel and the JustOne strip, and the results were compared to those obtained using the BACTEC 460 (BD, Sparks, MD) radiometric method and a broth microdilution reference method. Results obtained by the SLOMYCO panel and the JustOne strip agreed with the BACTEC 460 method for 64/71 isolates (90%). Similarly, concordance with the broth microdilution method was 40/43 isolates (93%) for both test systems. The effect of the source medium on inoculum preparation was evaluated, and there were no differences noted in MICs, regardless of whether the inoculum was prepared from isolates grown in Middlebrook 7H9 medium, on Middlebrook 7H10 agar, or in VersaTREK broth culture bottles (Trek Diagnostics). Clarithromycin susceptibility testing of MAC using the SLOMYCO panel and the JustOne strip methods is easy to set up and simple to read and is readily incorporate into the clinical laboratory. These systems offer advantages over the BACTEC 460 system including the lack of a need for radioactive substrates, sharps, or costly instrumentation.

ABSTRACTCryptococcus neoformansandCryptococcus gattiiare closely related pathogenic fungi.Cryptococcus neoformansis ecologically widespread and affects primarily immunocompromised patients, whileC. gattiiis traditionally found in tropical climates and has been reported to cause disease in immunocompetent patients.l-Canavanine glycine bromothymol blue (CGB) agar can be used to differentiateC. neoformansandC. gattii, but there are few reports of its performance in routine clinical practice. Growth ofC. gattiion CGB agar produces a blue color, indicating the assimilation of glycine, whileC. neoformansfails to cause a color change. Using reference and clinical strains, we evaluated the ability of CGB agar and D2 large ribosomal subunit DNA sequencing (D2 LSU) to differentiateC. neoformansandC. gattii.One hundred two yeast isolates were screened for urease activity, melanin production, and glycine assimilation on CGB agar as well as by D2 sequencing. Seventeen of 17 (100%)C. gattiiisolates were CGB positive, and 54 of 54C. neoformansisolates were CGB negative. Several yeast isolates other than theC. gattiiisolates were CGB agar positive, indicating that CGB agar cannot be used alone for identification ofC. gattii.D2 correctly identified and differentiated allC. gattiiandC. neoformansisolates. This study demonstrates that the use of CGB agar, in conjunction with urea hydrolysis and Niger seed agar, or D2 LSU sequencing can be reliably used in the clinical laboratory to distinguishC. gattiifromC. neoformans. We describe how CGB agar and D2 sequencing have been incorporated into the yeast identification algorithm in our laboratory.