Pathogenic fungi: An unacknowledged risk at coastal resorts? New insights on microbiological sand quality in Portugal

Abstract

Whilst the potential impact on beach users from microorganisms in water has received considerable attention, there has been relatively little investigation into microbial contaminants in sand. 33 beaches across Portugal were analyzed during a five year period (2006)(2007)(2008)(2009)(2010) to determine the presence of yeasts, pathogenic fungi, dermatophytes, total coliforms, E. coli and intestinal enterococci in sand.Our results showed that 60.4% of the samples were positive for fungi and that 25.2% were positive for the bacterial parameters. The most frequent fungal species found were Candida sp.and Aspergillus sp., whereas intestinal enterococci were the most frequently isolated bacteria.Positive associations were detected among analyzed parameters and country-regions but none among those parameters and sampling period.Regarding threshold values, we propose 15 cfu/g for yeasts, 17 cfu/g for potential pathogenic fungi, 8 cfu/g for dermatophytes. 84 cfu/g for coliforms, 250 cfu/g for E. coli, and 100 cfu/g for intestinal enterococciHighlights:x 60.4% of the analyzed marine beach sand samples were positive for the studied fungi x Candida sp. and Aspergillus sp. were the most frequent fungal species found x 25.2% of the analyzed marine beach sand samples were positive to the studied bacteria

Routine screening of harmful microorganisms in beach sands: Implications to public health

“…Based on variations in the concentrations of these microorganisms from beach to beach we proposed certain threshold values for selected microbiological indicators. The results of this study provided a useful baseline for assessment of sand beach microbiological flora, and served as a reminder of the occurrence of potentially harmful fungi and bacteria in these environments (Pereira et al, 2013;Sabino et al, 2011). The conclusions of this study are that beach cleaning improves the recreational qualities of the beach in terms of organic content in the sand, but that the impact of water quality is less evident.…”

“…An effective method for measuring fungi proposed by Sabino et al (2011) divides fungi into three practical groups: yeasts, potentially pathogenic and allergenic fungi, and dermatophytes. These fungal groups include all yeasts (except the black yeasts), the filamentous fungi of species of Aspergillus, Fusarium, Scopulariopsis, Scedosporium, Chrysosporium, Scytalidium, and, finally, all of the dermatophytes (Trichophyton, Microsporum and Epidermophyton) of clinical relevance.…”

“…Fungi associated with endemic infections (e.g., cocciodiomycosis and histoplasmosis) and any other fungi found in sand samples at N500 CFU/g of sand should be reported, according to Sabino et al (2011). Detection of any of the following fungi was considered to be of special concern among the participants of the workshop: Cryptococcus gattii, Cryptococcus neoformans, Histoplasma capsulatum, and Cladophialophora bantiana.…”

“…0.2 mL of the supernatant is then spread onto media in a Petri dish, followed by incubation, growth and identification of individual colonies of fungi. For bacteria, Colilert® and Enterolert® (IDEXX Laboratories, Inc., ME, USA) have been used to detect E. coli and enterococci, as thoroughly described in Sabino et al (2011). For the detection of helminth eggs a sedimentation method may be used.…”

“…Allowable levels after the local publishing of the latest revision of this directive in May 2012 (Law-decree 113/2012) include single sample maximums 1200 and 1800 CFU/100 mL for E. coli and 350 and 600 CFU/100 mL for enterococci, for coastal and transient waters and for inland waters, respectively. Although most of the local European regulations focus on reducing the number of water indicators through improved hygiene on surrounding areas, as imposed by the current European Directive, national surveys conducted by the authors on sand have shown that regulated beaches do not necessarily comply with the maximum locally determined mean levels, especially for fungi (including blue flag awarded beaches; Brandão et al, 2002 andSabino et al, 2011 (10 CFU/g for enterococci, 25 CFU/g for E. coli, 15 CFU/g for yeasts, 17 CFU/g for potential pathogenic fungi, 8 CFU/g for dermatophytes)). In the USA, these same bacteria are used for monitoring recreational water quality (US Environmental Protection Agency, 2012) with single sample maximums of 235 CFU/100 mL for E. coli and 104 CFU/100 mL for enterococci.…”