Matrix-assisted laser desorption/ionisation-time of flight mass spectrometry azole susceptibility assessment in Candida and Aspergillus species

BACKGROUND Matrix-assisted laser desorption/ionisation-time of flight mass spectrometry (MALDI-TOF MS) allows rapid pathogen identification and potentially can be used for antifungal susceptibility testing (AFST). OBJECTIVES We evaluated the performance of the MALDI-TOF MS in assessing azole susceptibility, with reduced incubation time, by comparing the results with the reference method Broth Microdilution. METHODS Resistant and susceptible strains of Candida (n = 15) were evaluated against fluconazole and Aspergillus (n = 15) against itraconazole and voriconazole. Strains were exposed to serial dilutions of the antifungals for 15 h. Microorganisms' protein spectra against all drug concentrations were acquired and used to generate a composite correlation index (CCI) matrix. The comparison of autocorrelations and cross-correlations between spectra facilitated by CCI was used as a similarity parameter between them, enabling the inference of a minimum profile change concentration breakpoint. Results obtained with the different AFST methods were then compared. FINDINGS The overall agreement between methods was 91.11%. Full agreement (100%) was reached for Aspergillus against voriconazole and Candida against fluconazole, and 73.33% of agreement was obtained for Aspergillus against itraconazole. MAIN CONCLUSIONS This study demonstrates MALDI-TOF MS' potential as a reliable and faster alternative for AFST. More studies are necessary for method optimisation and standardisation for clinical routine application.

Serum markers as an aid in the diagnosis of pulmonary fungal infections in AIDS patients

ABSTRACT Introduction: The etiology of pulmonary infections in HIV patients is determined by several variables including geographic region and availability of antiretroviral therapy. Materials and methods: A cross-sectional prospective study was conducted from 2012 to 2016 to evaluate the occurrence of pulmonary fungal infection in HIV-patients hospitalized due to pulmonary infections. Patients' serums were tested for (1-3)-β-D-Glugan, galactomannan, and lactate dehydrogenase. The association among the variables was analyzed by univariate and multivariate regression analysis. Results: 60 patients were included in the study. The patients were classified in three groups: Pneumocystis jirovecii pneumonia (19 patients), community-acquired pneumonia (18 patients), and other infections (23 patients). The overall mortality was 13.3%. The time since diagnosis of HIV infection was shorter in the pneumocystosis group (4.94 years; p = 0.001) than for the other two groups of patients. The multivariate analysis showed that higher (1-3)-β-D-Glucan level (mean: 241 pg/mL) and lactate dehydrogenase (mean: 762 U/L) were associated with the diagnosis of pneumocystosis. Pneumocystosis was the aids-defining illness in 11 out of 16 newly diagnosed HIV-infected patients. Conclusion: In the era of antiretroviral therapy, PJP was still the most prevalent pulmonary infection and (1-3)-β-D-Glucan and lactate dehydrogenase may be suitable markers to help diagnosing pneumocystosis in our HIV population.

Identificacao e antibiograma de actinomicetos aerobios isolados de amostras biologicas / Identification and antibiogram isolated aerobic actinomycete of biological specimens

Neste trabalho, a partir de amostras biologicas, foram realizados exames bacteriologicos para actinomicetos aerobios e, cepas mantidas em laboratorio, submetidas a processo de reidentificacao. Todos os microrganismos foram submetidos a antibiogramas, pela tecnica de difusao com discos. Cepas de Nocardia tambem o foram por meio da tecnica de diluicao em agar, a fim de se comprovar a existencia de correlacao entre os dois procedimentos. Dependendo da origem da amostra, o exame direto, mostrou-se importante para o diagnostico presuntivo de actinomicose. O meio de agar-sangue, em placas, permitiu o isolamento de microrganismos em estudo, mesmo de especimes extremamente contaminados. Agar Sabouraud dextrose e Lowenstein-Jensen, utilizados sob a forma inclinada, foram eficientes quando o actinomiceto era o unico agente ou ao menos, o predominante. Com base em testes bioquimicos e de suscetibilidade a antimicrobianos, foi possivel identificar 21 cepas, sendo 3 especies de Nocardia e 2 de Actinomadura, assim como foi possivel reclassificar as cepas anteriormente isoladas. Para a maioria dos microrganismos isolados, os diametros de halo de inibicao de amicacina, cefotaxima, gentamicina, sulfadiazina, sulfametoxazol-trimetoprim e tobramicina, forma maiores ou iguais 20mm; os de ampicilina, cloranfenicol e vancomicina nao se formaram ou alcancaram ate 46mm, e os de cefalotina, cefazolina, lincomicina, oxacilina e penicilina, foram iguais a zero. Para os 6 primeiros antimicrobianos, a analise estatistica demonstrou correlacao entre CIMs e diametros de halo de inibicao frente as especies estudadas, mostrando boas perspectivas para futura aplicacao da tecnica de difusao com discos em rotina laboratorial

Micose superficial da regiäo podal em indivíduos considerados imunocomprometidos / Feet superficial mycosis in cases condideredimmunocompromised

FUNDAMENTO - Micoses superficiais das regiöes podais representam as formas mais comuns de doenças fúngicas entre indivíduos sadios. Riscos de aquisiçäo de infecçöes disseminadas graves, por indivíduos imunodeprimidos, säo discutidos, carecendo, no entanto, a literatura, de relatos associados à ocorrência de micoses podais nesse grupo de pacientes. OBJETIVO - Estudo da ocorrência dessas micoses superficiais em transplantados renais, considerando grupo controle e diversos fatores predisponentes à aquisiçäo de micoses superficiais. PACIENTES E MÉTODOS - Por meio de procedimentos clássicos, foram realizados exames micológicos em 155 indivíduos sadios e 83 imunodeprimidos, a partir de amostras de pele e unha. RESULTADOS - Com base em análise estatística, verificou-se probabilidade de ocorrência de fungos em indivíduos com lesöes podais maior para os imunocomprometidos. Para eles, o hábito de uso constante de calçado fechado foi mais significativo na aquisiçäo de micose. Outros hábitos usualmente considerados fatores de risco mostraram correlaçäo para indivíduos sadios. De modo geral, Trichophyton rubrum foi o fungo isolado de maior frequência; Epidermophyton floccosum, diversas espécies de Candida e Trichosporon beigeli foram isolados sobretudo a partir dos imunocomprometidos. CONCLUSÃO - A presença de lesäo e o uso frequente de calçados fechados mostraram-se fatores importantes para aquisiçäo de micoses podais, principalmente por T. rubrum, entre os transplantados renais