Detection of triazole resistance among Candida species by matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS).

MALDI-TOF MS can rapidly identify microorganisms to the species level and may be able to detect antimicrobial resistance. We evaluated the ability of this technology to detect triazole resistance in Candida species.35 C. albicans, 35 C. glabrata, and 37 C. tropicalis strains were exposed to fluconazole, voriconazole, or posaconazole at two different concentrations plus a drug-free control: a midrange concentration (CLSI clinical breakpoint or epidemiologic cut-off value), and a high concentration (fluconazole 64 µg/ml, voriconazole & posaconazole 16 µg/ml). The MALDI-TOF MS spectra at these concentrations were used to create the individual composite correlation index (CCI) matrices for each isolate. When the CCI of the midrange/highest concentration was lower than that of the midrange/null concentration, the strain was classified as resistant. These results were then compared to the classifications for susceptible or resistant obtained by measuring the MICs according to the CLSI M27-A3 antifungal susceptibility testing (AFST) method.The MALDI-TOF MS assay was able to classify triazole susceptibility against all strains. Overall, essential agreement between MALDI-TOF MS and AFST varied between 54% and 97%, and was highest for posaconazole against C. glabrata. The reproducibility of the MALDI-TOF MS assay varied between 54.3 and 82.9% and was best for fluconazole against C. albicans and posaconazole against C. glabrata. Reproducibility was also higher for C. glabrata isolates compared to C. albicans and C. tropicalis.These results demonstrate that MALDI-TOF MS may be used to simultaneously determine the Candida species and classification as susceptible or resistant to triazole antifungals. Further studies are needed to refine the methodology and improve the reproducibility of this assay.

Species distribution and in vitro susceptibility of Candida bloodstream isolates to six new and current antifungal agents in a Turkish tertiary care military hospital, recovered through 2001 and 2006.

OBJECTIVE: Species distribution and antifungal susceptibility of Candida bloodstream isolates. METHODS: 173 Candida species recovered from fungemic patients admitted to the largest tertiary-care military hospital between 2001 and 2006 in Ankara, Turkey evaluated retrospectively. Antifungal susceptibility of 95 isolates (45 Candida parapsilosis, 35 C. albicans, 7 C. tropicalis, 4 C. krusei, 3 C. glabrata, and 1 C. kefyr) was determined against fluconazole, itraconazole, voriconazole, posaconazole, caspofungin, and amphotericin B. RESULTS: C. albicans was the most common yeast (48.0%), followed by C. parapsilosis. Almost all strains showed low minimal inhibitory concentration (MIC) values to all six antifungals tested. Only 2 of 45 C. parapsilosis isolates were resistant to fluconazole, one was susceptible in a dose-dependent manner (SDD) to itraconazole, and 14 were nonsusceptible to caspofungin. CONCLUSIONS: Increasing prevalence of C. parapsilosis emphasizes a need for better catheter care and continuous surveillance programs.

Intranasal fungi and chronic rhinosinusitis: what is the relationship?

OBJECTIVES: The aim of this study was to investigate the effects of intranasal fungi on chronic rhinosinusitis (CRS). METHODS: Forty-one patients with CRS were included in the study. The patients were put into 2 groups, with and without intranasal fungi as detected by polymerase chain reaction, and were compared in terms of different laboratory and clinical parameters of CRS. A chi2 test was used to analyze statistical differences between the 2 groups. RESULTS: Serum eosinophilia, eosinophilia in the nasal mucus, prick and intradermal test positivity for fungi, elevated total IgE, fungal-specific IgE, prevalence of symptoms, frequency of bronchial asthma, aspirin sensitivity, and nasal polyposis did not differ significantly between the 2 groups of patients (p > .05). CONCLUSIONS: The findings of this study failed to reveal a clear correlation between the presence of fungi in the nasal passage and various factors that are assumed to be involved in the pathogenesis or clinical course of CRS. If fungi have a role in the pathogenesis of CRS, it may be via other mediators and reactions rather than IgE and type I hypersensitivity. However, the sample size was relatively small, and further studies with more cases are needed on the same topic.

Clonal spread of serogroup W135 meningococcal disease in Turkey.

Six cases of Neisseria meningitidis serogroup W135 meningococcal infection have been reported in Turkey since 2003. Seven isolates recovered from four meningococcal meningitis patients and two asymptomatic carriers produced three distinct pulsed-field gel electrophoresis (PFGE) patterns. Multilocus sequence typing and antigen gene sequencing showed that five isolates were indistinguishable from ST-11 (ET-37) serogroup W135 meningococci, which were first isolated in Saudi Arabia and were responsible for the worldwide outbreak among Hajj pilgrims and their contacts in 2000. The remaining two isolates, which had related PFGE patterns, differed from each other at only one of the genetic loci characterized but were not related to the ST-11 clonal complex. None of the six individuals recalled contact with a pilgrim or had traveled on the Hajj. These six individuals exhibited no time or place relationships to each other, except for the two asymptomatic carriers, who were soldiers and served in the same military unit. These data demonstrate that serogroup W135 meningococci with different genotypes, including the Hajj epidemic strain, are endemic in Turkey.

[Karyotypic investigation of two cases of invasive candidiasis]. / Invaziv iki kandidoz olgusunun karyotipik olarak incelenmesi.

Investigation of the genetic relationship of the three Candida albicans strains isolated from each of two patients, one with C. albicans meningitis and the other with pancreatic pseudocyst (PP), by PFGE (pulsed-field gel electrophoresis), was aimed in this study. Three strains of C. albicans isolated from bloodstream, abscess and drainage fluid of the patient with PP were found to show the same karyotype, while three strains of C. albicans from cerebrospinal fluid, nasopharyngeal swab culture and stool sample of the patient with meningitis were found closely related. As a conclusion, PFGE enables to give valuable information about the probable source of transmission on individual basis in these two invasive candida infections.

Resistance patterns of Mycobacterium tuberculosis complex isolates in the Turkish Army from 1998 to 2000.

The aim of this retrospective study was to investigate susceptibility rates of Mycobacterium tuberculosis complex (MTBC) isolates against streptomycin, rifampicin, isoniazid, and ethambutol between January 1998 and December 2000 in the Turkish Army. Specimens collected from patients were cultured both conventionally and radiometrically. Differentiation of MTBC bacteria from Mycobacteria other than tuberculosis bacilli was made by the BACTEC p-nitro-alpha-acetyl-amino-beta-hydroxypropiophenone test. Susceptibility testing of MTBC isolates was performed using the BACTEC radiometric susceptibility assay for mycobacteria. Most of the specimens originated from respiratory system. A total of 98 isolates in 1998, 123 isolates in 1999, and 84 isolates in 2000 were obtained and identified as MTBC using the radiometric BACTEC TB460 system. Initial resistance was most frequent to isoniazid followed by ethambutol, streptomycin , and rifampicin in this study period. The differences between resistance rates were not statistically significant on an annual basis. None of these isolates was resistant to all four antimycobacterial agents. Although resistance rates of our isolates were not as high as previously reported by some authors from Turkey and there was no significant difference between the annual susceptibility rates, routine screening of antituberculosis drug susceptibility should be continued to control the resistance development and its spread.