María Mercedes Panizo

Candida spp. in vitro susceptibility profile to four antifungal agents. Resistance surveillance study in Venezuelan strains

The aim of this study was to determine in vitro susceptibility profiles of Venezuelan strains of Candida spp. to four antifungal agents. One hundred and forty five (145) isolates were recovered during a 1-year period (June 2006 to June 2007) from clinical specimens of patients with severe Candida spp. infections in 15 hospitals. In vitro susceptibilities to amphotericin B, fluconazole, itraconazole and voriconazole were determined by modified Etest. Non Candida albicans Candida spp. were the most frequently isolated yeasts (72.4%) in comparison with C. albicans (27.6%). Candida spp. strains showed MIC ranges between <0.002 and 0.5 mug/ml to amphotericin B. While none were found to be resistant to voriconazole, 5.5% and 27.6% of the test strains were resistant to fluconazole and itraconazole, respectively. C. albicans remains the most susceptible of the yeasts studied to fluconazole and itraconazole (P<0.05) when compared with non C. albicans Candida spp. C. krusei showed the greater cross-resistance to azoles, followed by C. glabrata, C. tropicalis and C. parapsilosis, while C. albicans isolates did not demonstrate this characteristic. It is very important to carry out the correct species identification of clinical yeast isolates because they show up variations in both distribution and susceptibility profiles according to the hospital, patients underlying disease, clinical specimen analyzed, and the geographical region in which the studies were conducted. The Mycology Department of the INHRR is the national reference center responsible for antifungal resistance surveillance, performing the susceptibility tests with isolates recovered from hospitalized patients in public health centres which do not have mycological diagnosis laboratories.

Pneumocystis jirovecii pneumonia in Latin America. A public health problem

Pneumocystis jirovecii pneumonia (PcP) is a well-recognized major opportunistic infection in HIV-infected patients. During the 1980s, the HIV pandemic turned PcP into a major worldwide medical and public health problem. With the introduction of Pneumocystis chemoprophylaxis and the development of highly active antiretroviral therapy (ART) for the treatment of HIV infection, there has been a decrease in PcP incidence in developed countries. However, the prevalence of AIDS-related PcP in developing countries remains high because a lot of people do not have access to ART or ignore their HIV infection status. This article discusses the information available about PcP among Latin American countries where there is a great regional heterogeneity in the prevalence of HIV infection and in ART coverage, as well as in the observed frequencies of PcP that range from 5.9 to 55% in this area.

Neumocistosis en pacientes venezolanos: diagnóstico y epidemiología (2001-2006)

The objective of this work was to investigate the epidemiology of pneumocystosis in Venezuelan patients utilizing a retrospective study during a six year period. One hundred and twenty nine clinical samples collected from patients with AIDS, cancer and non-AIDS-non-cancer low respiratory tract infection patients were processed by direct immunofluorescence technique. Pneumocystosis was diagnosed in 30 patients with a general frequency of 23.3%, which varied according to the patients group: 36.6% in AIDS patients, 38% in cancer patients, and 10.4% in non-AIDS-non-cancer low respiratory tract infection patients. This study demonstrated the existence of differences in pneumocystosis frequency related to the patients underlying disease, and that the illness is an important health problem in immunocompromised patients in Venezuela. Pneumocystosis must be suspected in non-immunocompromised patients with signs and symptoms of low respiratory tract infection, and the study of this illness must include COPD and cancer patients. Direct immunofluorescence is a useful technique for pneumocystosis diagnosis, however, it requires an optimal sample and skilled personnel in the laboratory.

Distribución y sensibilidad a los antifúngicos de aislamientos clínicos de Candida en seis centros de salud del área metropolitana de Caracas, Venezuela (años 2003-2005)

El objetivo de este estudio fue conocer la frecuencia y la sensibilidad a los antifungicos de aislamientos clinicos de Candida provenientes de pacientes con candidiasis en seis centros de salud del area metropolitana de Caracas, Venezuela. Se revisaron retrospectivamente los informes de laboratorio desde enero de 2003 hasta agosto de 2005. La identificacion de las levaduras aisladas se realizo por los metodos convencionales y se evaluo la susceptibilidad a los antifungicos por los metodos ATB-Fungus (bioMerieux, Francia) y Etest (AB Biodisk, Solna, Suecia). Se aislaron 1.977 levaduras y a 1.414 se les realizaron pruebas de sensibilidad. Candida albicans fue la levadura aislada con mas frecuencia (46.7%) y el resto de las especies de Candida representaron mas de la mitad de los aislamientos (53.4%). Todas las levaduras evaluadas presentaron valores de CMI <1 µg/ml para la anfotericina B y porcentajes de sensibilidad variable al fluconazol (91,5%), itraconazol (80%) y voriconazol (98,6%).The aim of this study was to investigate the frequency and antifungal susceptibility of Candida clinical isolations coming from patients with candidiasis in six health care centers of Caracas, Venezuela metropolitan area. The laboratory reports were retrospectively revised from January 2003 through August 2005. The isolated yeasts identification was carried out by conventional methods and antifungal susceptibility was evaluated by ATB-fungus (bioMérieux, France) and Etest (AB Biodisk, Solna, Sweden). One thousand nine hundred seventy seven (1.977) yeasts were studied and their susceptibility testing were carried out only in 1,414 of them. C. albicans was the most isolated yeast (46.7%) and none-albicans Candida-species represented more than half of the isolations (53.4%). All the isolated yeasts evaluated presented CMIs<1 microg/ml to anfotericina B and showed variable susceptibility percentages to fluconazole (91.5%), itraconazole (80%) and voriconazole (98.6%).

Identificación molecular y sensibilidad a los antifúngicos de aislamientos de sangre del complejo Candida parapsilosis en Venezuela

BACKGROUND Candida parapsilosis is a species complex consisting of Candida parapsilosis sensu stricto, Candida orthopsilosis, and Candida metapsilosis. Studies worldwide have described its epidemiology and susceptibility to antifungal agents. AIMS The aims of this study were to carry out the molecular identification of blood isolates belonging to the Candida parapsilosis species complex, and to determine their in vitro susceptibility to antifungals of systemic use. METHODS A study of 86 strains of C. parapsilosis species complex collected in 2008-2011 and obtained from the Candidaemia Surveillance Network of Mycology Department of the Rafael Rangel National Institute of Hygiene, was made. Secondary alcohol-dehydrogenase gene amplification was performed using polymerase chain reaction, and the products were analysed by restriction fragments length polymorphisms using the enzyme BanI. Susceptibility tests were performed using Etest®, following the manufacturers instructions with modifications. RESULTS Of the 86 isolates studied, 81 (94.2%) were C. parapsilosis sensu stricto, 4 (4.6%) C. orthopsilosis, and one (1.2%) C. metapsilosis. C. parapsilosis isolates were susceptible to amphotericin B and caspofungin, showing low rates of resistance to fluconazole and voriconazole. C. orthopsilosis and C. metapsilosis were susceptible to all the antifungals tested. CONCLUSIONS The results obtained in Venezuela provide for the first time important information about the distribution of C. parapsilosis species complex in cases of candidaemia, and support the need for continuing surveillance programs, including molecular discrimination of species and antifungal susceptibility tests, which may guide specific therapy.

Histoplasma capsulatum antigen detection tests as an essential diagnostic tool for patients with advanced HIV disease in low and middle income countries: A systematic review of diagnostic accuracy studies

Introduction Disseminated histoplasmosis, a disease that often resembles and is mistaken for tuberculosis, is a major cause of death in patients with advanced HIV disease. Histoplasma antigen detection tests are an important addition to the diagnostic arsenal for patients with advanced HIV disease and should be considered for inclusion on the World Health Organization Essential Diagnostics List. Objective Our objective was to systematically review the literature to evaluate the diagnostic accuracy of Histoplasma antigen tests in the context of advanced HIV disease, with a focus on low- and middle-income countries. Methods A systematic review of the published literature extracted data on comparator groups, type of histoplasmosis, HIV status, performance results, patient numbers, whether patients were consecutively enrolled or if the study used biobank samples. PubMed, Scopus, Lilacs and Scielo databases were searched for published articles between 1981 and 2018. There was no language restriction. Results Of 1327 screened abstracts we included a total of 16 studies in humans for further analysis. Most studies included used a heterogeneousgroup of patients, often without HIV or mixing HIV and non HIV patients, with disseminated or non-disseminated forms of histoplasmosis. Six studies did not systematically use mycologically confirmed cases as a gold standard but compared antigen detection tests against another antigen detection test. Patient numbers were generally small (19–65) in individual studies and, in most (7/10), no confidence intervals were given. The post test probability of a positive or negative test were good suggesting that this non invasive diagnostic tool would be very useful for HIV care givers at the level of reference hospitals or hospitals with the infrastructure to perform ELISA tests. The first results evaluating point of care antigen detection tests using a lateral flow assay were promising with high sensitivity and specificity. Conclusions Antigen detection tests are promising tools to improve detection of and ultimately reduce the burden of histoplasmosis mortality in patients with advanced HIV disease.