Valério Rodrigues Aquino

Update on the contribution of galactomannan for the diagnosis of invasive aspergillosis.

The diagnosis of invasive fungal infections (IFI) remains a challenge, particularly for diseases caused by filamentous fungi such as Aspergillus species. Unfortunately, many patients affected by these conditions are not identified before autopsy. Therefore, there is a need for new diagnostic methods for IFI. Galactomannan is a soluble antigen released during hyphal growth in tissues. A commercially available sandwich ELISA assay that detects galactomannan has been used in Europe for many years and is now approved for use in the USA. The test has an excellent negative predictive value in the detection of invasive aspergillosis (IA) in high-risk patients. In addition, it is more sensitive than culture and allows IA to be diagnosed before clinical manifestations occur. However, false-negative and false-positive results in certain populations are the main limitations to its use. The purpose of this review is to summarize the current knowledge about galactomannan testing in patients at risk for IA.

Epidemiology and Outcome of Rhodotorula Fungemia in a Tertiary Care Hospital

We reviewed demographic data, risk factors, treatment, and outcomes associated with Rhodotorula fungemia in a tertiary care hospital during 2002-2005. Rhodotorula species caused fungemic episodes in 7 patients during the 4-year period that we studied. The most common predisposing factors were patients with hematological and solid malignancy receiving corticosteroids and cytotoxic drugs, the presence of central venous catheters, and the use of broad-spectrum antibiotics. Because of Rhodotorula speciess intrinsic resistance to triazole and echinocandin antifungal agents, patients receiving fluconazole and caspofungin might be susceptible to the development of breakthrough Rhodotorula fungemia.

Prevalence, susceptibility profile for fluconazole and risk factors for candidemia in a tertiary care hospital in southern Brazil

Bloodstream infections caused by yeast, Candida spp, are quite important clinically and epidemiologically due to a high mortality rate and an increasing number of non-albicans species with a more resistant (differentiated susceptibility) profile. We examined species prevalence and susceptibility profile for fluconazole and the risk for nosocomial infections by Candida spp at the Hospital de Clínicas de Porto Alegre, a general tertiary care hospital in southern Brazilian, through a retrospective study, beginning with positive cultures of hospitalized patients. The distribution by species in 131 documented episodes was as follows: Candida albicans (45%), C. parapsilosis (24.4%), C. tropicalis (15.3%), C. glabrata (6.9%), C. krusei (4.6%) and 3.8% other species (C. pelicullosa, C. guilliermondii, C. lusitaniae and C. kefyr). The vast majority of samples (121- 92.4%) were susceptible to fluconazole; the resistant or dose-dependent sensitive samples included only C. krusei and C. glabrata. Blood diseases (leukemia, lymphoma), or neoplasias (solid tumors), were found in 35.0% of the candidemia episodes. We noted the previous use of antibiotics in 128 (97.7%) patients, with 79.7% using three or more antibiotics before the candidemia episode. Other risk factors included a central venous catheter in 94 (71.8%) and abdominal surgery in 32 (24.4%) patients. The overall mortality rate was 51.9%, which varied according to the underlying disease. We found that C. albicans was the most prevalent species, although the non-albicans species predominated. However, in vitro resistance to fluconazole was detected only among the species (C. glabrata and C. krusei) that tend to be resistant to the azolic compounds. Previous use of antibiotic and the use of a central venous catheter were the main risk factors among patients with candidemia.

Cryptic and Rare Aspergillus Species in Brazil: Prevalence in Clinical Samples and In Vitro Susceptibility to Triazoles

ABSTRACT Aspergillus spp. are among the most common causes of opportunistic invasive fungal infections in tertiary care hospitals. Little is known about the prevalence and in vitro susceptibility of Aspergillus species in Latin America, because there are few medical centers able to perform accurate identification at the species level. The purpose of this study was to analyze the distribution of cryptic and rare Aspergillus species among clinical samples from 133 patients with suspected aspergillosis admitted in 12 medical centers in Brazil and to analyze the in vitro activity of different antifungal drugs. The identification of Aspergillus species was performed based on a polyphasic approach, as well as sequencing analysis of the internal transcribed spacer (ITS) region, calmodulin, and β-tubulin genes and phylogenetic analysis when necessary. The in vitro susceptibility tests with voriconazole, posaconazole, and itraconazole were performed according to the CLSI M38-A2 document (2008). We demonstrated a high prevalence of cryptic species causing human infection. Only three isolates, representing the species Aspergillus thermomutatus, A. ochraceus, and A. calidoustus, showed less in vitro susceptibility to at least one of the triazoles tested. Accurate identifications of Aspergillus at the species level and with in vitro susceptibility tests are important because some species may present unique resistance patterns against specific antifungal drugs.

Cutaneous Cryptococccosis Due to Cryptococcus gattii in Immunocompetent Hosts: Case Report and Review

Cutaneous cryptococcosis caused by C. gattii, in immunocompent patients is a rare manifestation of disease, and may be one of the first manifestations of disseminated cryptococcosis. We report a case of disseminated cryptococcosis caused by Cryptococcus gattii presenting as cutaneous lesions in an immunocompetent patient. Previously to our report, only five cases of cutaneous involvement by Cryptococcus gattii in immunocompetent patients have been reported in the literature. Risk factors for C. gattii infection included exposure to the eucalypt reservoirs in tropical and subtropical areas. Skin involvement corresponded to the disseminated form of cryptococcosis in the majority of patients, and commonly affected the face and neck with different morphologies including papules, pustules, plaques, ulcers, subcutaneous masses, cellulitis or acneiform lesions. Due to the severity of this infection and the life threatening condition that it represents, clinicians must be aware that cutaneous involvement may be one of the first manifestations of disseminated cryptococcosis caused by C. gattii especially in patients living and coming from endemic areas.

The performance of real-time PCR, galactomannan, and fungal culture in the diagnosis of invasive aspergillosis in ventilated patients with chronic obstructive pulmonary disease (COPD).

Emerging reports have associated chronic pulmonary obstructive disease (COPD) with invasive aspergillosis (IA), particularly in patients treated with mechanical ventilation and/or corticosteroids. This is a multicentre study in which COPD patients demonstrating a new lung infiltrate while being mechanically ventilated were prospectively evaluated for the presence of IA. From the 47 patients studied, Aspergillus fumigatus was recovered in culture in two patients (4.2%). While serum galactomannan (GM) was negative for 94% of patients, GM levels in respiratory samples were >0.5, >1.0 and >1.5 for 74.5, 40.5, and 21.3% of patients, respectively. PCR was positive for 10 patients in the study but did not differentiate Aspergillus colonization from infection. The combination of PCR and GM in respiratory samples may be an interesting alternative to diagnose IA in COPD patients.

Galactomannan detection from piperacillin-tazobactam brands available in the Brazilian market

Piperacillin-tazobactam is a broad spectrum antimicrobial agent that can cause false-positive results in the commercial Platelia Aspergillus EIA test. So far, no study has been performed in Latin America to evaluate the clinical implication of this finding. Here we studied the potential for galactomannan detection in piperacillin-tazobactam batches commercialized in the Brazilian market. Five batches from distinct laboratories were tested in duplicate in the Platelia Aspergillus EIA according to the manufacturers instructions. Only one drug showed crossreaction at a cut-off of 0.5. Human serum was spiked with this particular drug aiming to mimic achievable piperacillin-tazobactam concentrations in the serum. Results were all negative for galactomannan detection, even at high drug concentrations. Results from this pilot study suggest that piperacillin-tazobactam might not be a clinically significant cause of false-positive results in the Platelia Aspergillus EIA test in Brazil.

Paecilomyces variotii as an Emergent Pathogenic Agent of Pneumonia

Paecilomyces variotii is a commonly occurring species in air and food, and it is also associated with many types of human infections. Pneumonia due to Paecilomyces variotii has been rarely reported in the medical literature. The authors report a 48-year-old patient with refractory lymphoma who underwent allogenic hematopoietic cell transplantation and developed pneumonia due to Paecilomyces variotii. They also review the published case reports of pneumonia caused by this fungus.

The indoor air as a potential determinant of the frequency of invasive aspergillosis in the intensive care.

Invasive aspergillosis (IA) seems to be an emerging condition in intensive care units (ICUs). However, little attention has been given to the role of environmental factors that could increase the risk for IA in the ICU. The objective of this study was to determine the concentration of airborne fungi in three Brazilian ICUs, in an attempt to correlate fungal burden with the frequency of Aspergillus spp isolation from clinical samples of patients hospitalised in these units. During a 1‐year period we quantitatively evaluated the presence of fungi in the air of three ICUs in Porto Alegre, Brazil. The quantity of fungi was correlated with environmental factors. Only one of the ICUs studied showed equal concentrations of Aspergillus conidia in the indoor air, in comparison with the outdoor environment. All cases of Aspergillus colonisation and IA cases observed during the study occurred in that particular ICU. Environmental factors have a direct influence on fungal spore concentration in the air in ICUs, as well as air filtration systems in air conditioners. Fungal contamination of the indoor air may influence the frequency of AI in ICU patients.

Variability in Galactomannan detection by Platelia Aspergillus EIA™ according to the Aspergillus species.

Here we investigate the extent to which different Aspergillus species release galactomannan (GM) in vitro. Marked variability was observed in GM reactivity between and within Aspergillus species, with A. terreus strains showing the highest GM indexes. The in vivo significance of these findings remains to be determined.