Identification and Susceptibility Testing on Samples of Mycobacterium spp.

Background: Tuberculosis is still a major global health problem. Human tuberculosis is caused by species of bacteria belonging to the Mycobacterium genus. In this study we determined mycobacterial species affecting patients from Botucatu, Brazil, and tested M. tuberculosis sensitivity to different drugs. Methods: Data were obtained from Clinical Laboratory Analysis records at Botucatu Medical School University Hospital, UNESP. All samples were processed according to standard isolation procedures from the 2008 Brazil Ministry of Health Mycobacteria Manual, which consist of staining smears by the Ziehl-Neelsen technique and seeding cultures in the Löwenstein-Jensen medium. Results: Samples were isolated from sputum (80.5%), bronchoalveolar lavage (13.8%), pleural fluid (4.6%), and cerebrospinal liquor (1.1%). Smears were evaluated in 87 cases and a total of 59 patients showed positive smears; 55 from 70 sputum samples and 4 from 12 bronchoalveolar lavage samples. No pleural fluid (4) or cerebrospinal liquor (1) samples showed positive smears. The most commonly identified strain was M. tuberculosis (61 cases); followed by M. avium and M. gordonae 2 cases each, and M. peregrinum and M. abscessus 1 case each. Mycobacteria were not identified in 20 patients. Only two strains of M. tuberculosis were multidrug resistant; one was resistant to isoniazid, rifampicin, and pyrazinamide. These two patients evolved to cure. Conclusion: This study highlights a small but troubling percentage of multidrug resistant samples and reveals the occurrence of nontuberculous mycobacteria, emphasizing the importance of correctly identifying species and testing sensitivity to antibacilar drugs to assure an adequate therapy.

Candida spp: manual identification (reference method) and automated identification (Vitek system platform)

Yeasts are becoming a common cause of nosocomial fungal infections that affect immunocompromised patients. Such infections can evolve into sepsis, whose mortality rate is high. This study aimed to evaluate the viability of Candida species identification by the automated system Vitek-Biomerieux (Durham, USA). Ninety-eight medical charts referencing the Candida spp. samples available for the study were retrospectively analyzed. The system Vitek-Biomerieux with Candida identification card is recommended for laboratory routine use and presents 80.6% agreement with the reference method. By separate analysis of species, 13.5% of C. parapsilosis samples differed from the reference method, while the Vitek system wrongly identified them as C. tropicalis, C. lusitaneae or as Candida albicans. C. glabrata presented a discrepancy of only one sample (25%), and was identified by Vitek as C. parapsilosis. C. guilliermondii also differed in only one sample (33.3%), being identified as Candida spp. All C. albicans, C. tropicalis and C. lusitaneae samples were identified correctly.

Candidemia in a brazilian tertiary hospital: microbiological and clinical features over a six-year period

Yeasts are becoming a common cause of nosocomial fungal infections in immunocompromised patients. Such infections often develop into sepsis with high mortality rates. The aim of this study was to evaluate some of the numerous factors associated with the development of candidemia. Medical records were retrospectively analyzed of 98 Candida spp. patients. Results showed that the most prevalent risk factors for developing candidemia were: antibiotics and antifungal agents (93.9% and 79.6%, respectively); the use of central venous catheter (93.9%); mechanical ventilation (73.5%); and parenteral nutrition (60.2%). The main species of Candida found were: C. parapsilosis (37.76%), C. albicans (33.67%); and others (28.57%). C. glabrata showed the highest mortality rate (75%), followed by C. tropicalis (57.1%) and C. albicans (54.5%). The elevated mortality rate found in this study indicates that preventive measures against candidemia must be emphasized in hospitals.(AU)