Candida species contamination in drinking groundwater from residence wells in three municipalities of midwestern Brazil and the potential human health risks.

Groundwater represents one of the largest safe drinking water sources worldwide; however, it has been threatened by increased human activities in recent years. Candida species express virulence factors that contribute to the establishment and worsening of infections, although little is known about the virulence profiles of these species in potable groundwater. The aim of this study was to detect the presence of yeasts in groundwater from residential wells and to evaluate the antifungal susceptibility profile, hydrolytic enzyme production, adhesion capacity, and biofilm formation of Candida spp. Fifty yeasts representing nine genera were isolated: Candida (48%), Meyerozyma (20%), Pichia (8%), Exophiala (8%), Clavispora (4%), Kodamaea (4%), Rhodotorula (4%), Hanseniaspora (2%), and Kazachstania (2%). Candida parapsilosis was the most commonly isolated species, and approximately 29% of the Candida isolates were resistant to at least one azole. All Candida isolates were able to produce hydrolytic enzymes and adhere to polystyrene, and most were classified as hydrophobic. Candida spp. can establish and form biofilms when cultivated in different media such as Sabouraud broth, water, and calcium hypochlorite. The use of contaminated groundwater for human consumption represents a possible route for the transmission of clinically relevant yeasts that can cause fungal infections, especially in immunocompromised individuals. Therefore, it is important to evaluate and establish effective measures for groundwater treatment to ensure the quality and safety for consumption.

Modulation of ERG Genes Expression in Clinical Isolates of Candida tropicalis Susceptible and Resistant to Fluconazole and Itraconazole.

Candida tropicalis is a non-albicans Candida specie that causes candidosis in several countries, including Brazil. However, little is known about the mechanisms of drug resistance in C. tropicalis infections. In this study, we used clinical isolates of C. tropicalis susceptible as well as resistant to either Fluconazole or Itraconazole to assess the relationship between drug resistance and the expression of ERG and efflux pump genes. Our results showed that the main mechanism of resistance against both Fluconazole and Itraconazole in this specie is through the up-regulation of ERG rather than that of the efflux pump genes. We demonstrated that, although pre-treatment with azole drugs increases the expression of both ERG6 and ERG11 genes, the resistant or susceptible dose-dependent (SDD) samples are able to maintain high expression levels of these genes for longer periods of time than the susceptible samples.

KPC: an important mechanism of resistance in K. pneumoniae isolates from intensive care units in the Midwest region of Brazil.

INTRODUCTION: Infections caused by multidrug-resistant Klebsiella pneumoniae are difficult to treat and pose a serious threat to public health worldwide. Here, we describe the presence of carbapenemase-producing K. pneumoniae in intensive care units (ICU) of three major Mato Grosso do Sul hospitals located in the Midwest region of Brazil. METHODOLOGY: A total of 165 K. pneumoniae isolates with reduced susceptibility to carbapenems as identified by the VITEK-2 compact system were studied. Antimicrobial susceptibility testing was performed using the disk diffusion method, as recommended by the Clinical and Laboratory Standards Institute, and the E-test method. The detection of carbapenemase was performed using the modified Hodge test and polymerase chain reaction. RESULTS: The blaKPC gene was identified in 88.1% (n=89) of the selected K. pneumoniae isolates from Beneficent Association of Campo Grande, 94.9% (n=34) of the isolates from the Regional Hospital of Mato Grosso do Sul and 95.2% (n=26) of the isolates from Maria Aparecida Pedrossian University Hospital. Resistance greater than 80% was observed against cephalosporins, aztreonam, ciprofloxacin and piperacillin/tazobactam. Carbapenemase-producing K. pneumoniae (Kp-KPC) isolates were considered important causative agents of urinary tract infections, pneumonia and bloodstream infections in ICU patients. While rarely reported in the literature, we documented three cases of meningoencephalitis caused by Kp-KPC. CONCLUSIONS: Our study documents the presence of Kp-KPC in three major Mato Grosso do Sul state hospitals, providing key national epidemiology data. This is an important mechanism of resistance in K. pneumoniae isolates from ICU patients and is associated with resistance to multiple classes of antimicrobial drugs.