Differential expression of virulence factors in clinical isolates of Candida parapsilosis / 中国感染控制杂志

Objective To compare the differences in virulence-related factor aspartate protease,biofilm formation,and gene expression among clinical isolates of Candida parapsilosis(C.parapsilosis).Methods Gene sequencing and microsatellite typing(MT)method were adopted to identify C.parapsilosis isolated from patients with clinical fungal infection.The production of secreted aspartate protease and biofilm formation ability of each strain were de-tected,and the expression of biofilm formation related-genes BCR1,EFG1,and HWP1,as well as aspartate prote-ase virulence genes SAPP1,SAPP2,SAPP3 were compared among the strains.Results A total of 8 clinically iso-lated C.parapsilosis strains were collected,all of which were identified as genotype Ⅰ.Based on microsatellite ty-ping results,8 clinical strains were divided into 4 microsatellite types.G1,G2,and G3 strains isolated from the urine,peripherally inserted central catheters(PICC),and blood of patient A were of different subtypes.J1,J2,J3,J4,and J5 strains were of the same type,and isolated from blood specimens of patient B at different periods.All 8 clinical strains could form biofilm,and their biofilm formation ability was higher than that of the standard strain of C.parapsilosis(ATCC 22019).G1,G3 and J5 strains had strong biofilm formation ability,J1,J2,J3,and J4 strains had moderate biofilm formation ability,and G2 strain had weak biofilm formation ability.All of the eight clinical isolates secreted aspartate protease,and their in vitro expression levels of the enzyme were higher than that of the standard strain(ATCC 22019).G3,G1,and G2 strains showed low,moderate,and high in vitro enzyme expression respectively,with statistical differences(all P＜0.05).Enzyme expressed moderately in J1 and J5 strains,and highly in J2,J3,and J4 strains.Difference between moderate and high expressions was statistically significant(P＜0.05).The expression levels of biofilm formation genes BCR1,EFG1,and HWP1 in various strains isolated from patients A and B increased.In strains isolated from patient A,the expression level of EFG1 gene in G1 strain was higher than that in G2 strain(P＜0.05).There was no statistically significant difference in BCR1,EFG1,and HWP1 gene expression levels among strains isolated from patient B.The expression levels of as-partate protein genes(SAPP1,SAPP2,and SAPP3)in various strains isolated from patients A and B increased.The expression levels of SAPP1 and SAPP2 in strain G1 were higher than those in G2 and G3(both P＜0.05).There was no statistically significant difference in the expression levels of SAPP1,SAPP2,and SAPP3 genes in strains from patient B.Conclusion Clinical isolates of C.parapsilosis have higher biofilm formation and aspartate protease production abilities than standard strain.The expression of virulence factors varies among strains isolated from different specimens,while there is no significant difference in the expression of virulence factors among strains isolated at different periods.Patients may have been infected with different MT types of C.parapsilosis in multiple sites during the same period.

Risk factors and pathogen analysis of candidemia in cancer patients / 中国肿瘤临床

Objects: To clarify the risk factors of candidemia and to assess the clinical differences that may exist between infection with Candida parapsilosis and that with other Candida species in cancer patients. To statistically analyze the clinical characteristics of Candi-da albicans candidemia and C. parapsilosis candidemia and risk factors for their infections. We aimed at a timely intervention through this type of analysis to avoid susceptible factors and improve the prognosis of patients with candidemia. Methods: We retrospectively included 323 patients with candidemia in Affiliated Cancer Hospital of Zhengzhou University between March 2012 and February 2018 and analyzed the clinical characteristics of these patients to establish the risk factors of candidemia. We performed a comparative anal-ysis of the clinical characteristics of C. parapsilosis infections and non-parapsilosis Candida spp. infections and of C. albicans infections and non-albicans Candida spp. infections. In addition, drug sensitivity tests and analyses were performed with the common antifungal drugs used in Candida infections by a micro-broth dilution method. The statistical software SPSS version 22 was used for the analyses. Results: A total of 323 patients were enrolled and analyzed in this study. Of the isolates, 34.37% were C. albicans and 65.63% were non-albicans Candida spp. Multivariate regression analysis showed that the following factors were associated with the occurrence of C. parapsilosis candidemia: parenteral nutrition (P<0.001), neutropenia (P<0.001), history of receiving chemotherapy (P=0.002), and history of previous antifungal use (P<0.001). Parenteral nutrition was found to be an independent risk factor for C. albicans candi-demia (OR=0.183; 95%CI:0.098?0.340; P<0.001). Conclusions: C. parapsilosis was found to be the primary pathogen in cancer patients with candidemia. Total parenteral nutrition in the intensive care unit at diagnosis and abdominal surgery were independent risk factors of candidemia, and parenteral nutrition was an independent risk factor of C. parapsilosis candidemia. At present, C. parapsilosis is sur-passing C. albicans as the main pathogen of candidemia in cancer patients at our hospital. This study emphasizes the need to assess the possible risk factors for candidemia in cancer patients and aims at strengthening and developing a hospital-based control strategy to prevent the spread of candidemia.

Contaminação fúngica no leite humano e em sítios anatômicos de lactantes e lactentes / Fungal contamination in human milk and in the anatomic sites of breastfeeding mothers and infants

As infecções bacterianas ou fúngicas causam quadro clínico de mastite, que motiva desmame precoce. Os micro-organismos patogênicos, como leveduras do gênero Candida, quando em número elevado no intestino, podem causar disbiose. Nesta pesquisa, foram realizadas a detecção e a identificação de microbiota fúngica nas amostras de leite humano e de sítios anatômicos de mulheres e crianças atendidas pelo Banco de Leite Humano do Instituto Fernandes Figueira. A virulência dos isolados de levedura foi determinada pelos testes de atividade proteolítica. De 64 amostras analisadas, 81% foram positivas para fungos, com maior prevalência de Candida albicans (73%), seguida do complexo C. parapsilosis (15,4%). Perfis semelhantes aos verificados no total de amostras foram encontrados nas amostras de leite, nas mamas e na cavidade oral, sugerindo-se a ocorrência de associação entre a infecção cutânea da mãe e do lactente com o leite ingerido. O perfil associado à virulência dos isolados de Candida foi determinado pelo teste de produção de proteases, e 100% das amostras mostraram resultados fortemente positivos, indicando alto grau de infecciosidade. A alta prevalência de C. albicans nas amostras coletadas de mamas, no leite e na cavidade oral, é importante fator de risco à saúde de lactentes.

Clinical and Laboratory Features of Candidemia Caused by Different Candida Species / 대한진단검사의학회지

BACKGROUND: Recently, the incidence of candidemia due to Candida species other than C. albicans have increased. In this study, we analyzed the laboratory and clinical characteristics of candidemia caused by four different Candida species (C. albicans, C. parapsilosis, C. tropicalis and C. glabrata) occurring at Chonnam National University Hospital (CNUH). METHODS: The demographic, clinical and microbiological data of 157 patients with candidemia at CNUH from 1996 to 2002 was analyzed, retrospectively. The etiologic agents for 157 cases of candidemia were C. albicans (n=48), C. parapsilosis (n=48), C. tropicalis (n=32) and C. glabrata (n= 29). The characteristics of candidemia due to each single Candida species were compared with those with all other species combined. RESULTS: Although the majority (77%) of candidemic patients were adults, candidemia due to C. albicans or C. parapsilosis occurred significantly more often in premature infants (15%, retrospectively, P=0.002), in comparison with other Candida species (0%). Candidemia due to C. glabrata was more common in patients with neutropenia (41%, P<0.001), and they also occurred frequently in the absence of central venous catheter related candidemia (86%, P<0.001). Bloodstream infections with C. parapsilosis were more frequently the cause of catheter related candidemia (56%, P=0.012), and they had a better clinical outcome (90%, P=0.004) than those with other Candida species. CONCLUSIONS: This study confirms that some characteristics of candidemia such as age, underlying conditions, relatedness of catheter, and outcome can be different according to the species of Candida.