ATR-FTIR Spectroscopy Highlights the Problem of Distinguishing Between Exophiala dermatitidis and E-phaeomuriformis Using MALDI-TOF MS

WOS: 000369061400008PubMed ID: 26373644The present study compared two chemical-based methods, namely, matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF MS) and attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, to understand the misidentification of Exophiala dermatitidis and Exophiala phaeomuriformis. The study utilized 44 E. dermatitidis and 26 E. phaeomuriformis strains, which were partially treated with strong acids and bases for further evaluation. MALDI-TOF MS and ATR-FTIR spectroscopy data of the two Exophiala species were compared. Data groupings were observed for the chromic acid- and nitric acid-treated species when the black yeast sources were categorized as creosoted-oak sleepers, concrete sleepers, or dishwasher isolates. The MALDI-TOF MS data for the metalloenzyme-containing regions were consistent with the ATR-FTIR spectroscopy data. These results indicated that environmental isolates might contain metals not found in human isolates and might interfere with chemical-based identification methods. Therefore, MALDI-TOF MS reference libraries should be created for clinical strains and should exclude petroleum-associated environmental isolates

Epidemiology of pertussis in adolescents and adults in Turkey

Two hundred and fourteen patients who had a cough illness lasting at least 2 weeks were studied to investigate Bordetella pertussis as a cause of prolonged cough in adolescents and adults. Medical history and nasopharyngeal swab specimens for culture and polymerase chain reaction (PCR) were obtained at presentation. Three (1.4%) patients were B. pertussis culture-positive; 15 (7%) were B. pertussis PCR-positive (including the culture-positive patients) and 11 (5.1%) were Bordetella spp. PCR-positive. Symptom combinations were significantly high both in patients with pertussis and patients with indeterminate results (P < 0.05). We conclude that B. pertussis should be considered among differential diagnoses of prolonged cough in adolescents and adults and PCR and culture should be used to detect these cases and facilitate public health response