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Open Access Research article

The water supply system as a potential source of fungal infection in paediatric haematopoietic stem cell units

Sabrina Mesquita-Rocha1, Patricio C Godoy-Martinez2, Sarah S Gonçalves1, Milton Daniel Urrutia3, Fabianne Carlesse4, Adriana Seber4, Maria Aparecida Aguiar Silva4, Antônio Sérgio Petrilli4 and Arnaldo L Colombo1*

Author Affiliations

1 Departamento de Medicina, Disciplina de Infectologia, Universidade Federal de São Paulo, Rua Napoleão de Barros 590, Vila Clementino, São Paulo 04024-002, Brazil

2 Instituto de Microbiología Clínica, Edificio de Ciencias Biomédicas, 2 piso, Universidad Austral de Chile, Isla Teja, Valdivia, Chile

3 Universidad de Antofagasta, Avenida Angamos 201, Antofagasta, Chile

4 Instituto de Oncologia Pediátrica, GRAACC, Universidade Federal de São Paulo, Rua Botucatu 743, Vila Clementino, São Paulo, SP 04023-062, Brazil

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BMC Infectious Diseases 2013, 13:289  doi:10.1186/1471-2334-13-289

Published: 26 June 2013

Abstract

Background

We conducted a prospective study to investigate the presence of microfungal contamination in the water supply system of the Oncology Paediatric Institute, São Paulo – Brazil after the occurrence of one invasive Fusarium solani infection in a patient after Haematopoietic Stem Cell Transplantation (HSCT). During a twelve-month period, we investigated the water supply system of the HSCT unit by monitoring a total of fourteen different collection sites.

Methods

One litre of water was collected in each location, filtered through a 0.45 μm membrane and cultured on SDA to detect the presence of filamentous fungi. Physicochemical analyses of samples were performed to evaluate the temperature, turbidity, pH, and the concentration of free residual chlorine.

Results

Over the 12 months of the study, 164 samples were collected from the water supply system of the HSCT unit, and 139 of the samples tested positive for filamentous fungi (84.8%), generating a total of 2,362 colonies. Cladosporium spp., Penicillium spp., Purpureocillium spp. and Aspergillus spp. were ranked as the most commonly found genera of mould in the collected samples. Of note, Fusarium solani complex isolates were obtained from 14 out of the 106 samples that were collected from tap water (mean of 20 CFU/L). There was a positive correlation between the total number of fungal CFU obtained in all cultures and both water turbidity and temperature parameters. Our findings emphasise the need for the establishment of strict measures to limit the exposure of high-risk patients to waterborne fungal propagules.

Conclusions

We were able to isolate a wide variety of filamentous fungi from the water of the HSCT unit where several immunocompromised patients are assisted.

Keywords:
Filamentous fungi; Nosocomial water; Aspergillosis; Fusariosis; Fungal propagules