Scope ambiguities

1 _{Escola Superior de Tecnologia da Saúde de Lisboa, Portugal | [email protected]}

2 _{Laboratório de Micologia do Instituto Nacional de Saúde Dr. Ricardo Jorge, Portugal | [email protected]}

A

Introduction Hospital-wide surveillance studies have shown the presence of various potentially pathogenic

fungal species in health care settings. Fungal load characterization can be used to determine the degree of cleanliness and also to assess risk sources for airborne nosocomial infections. Objectives To monitor air fungal contamination in ten hospitals food units from Lisbon. Material and methods Fifty air samples of 250 litres were collected through impaction method. Air samples were collected in food storage facilities, kitchen, food plating, canteen and also, outside premises, since this was the place regarded as reference.

Results Thirty two species of fungi in indoor air were identified. Despite the two most commonly isolated

were Penicillium sp. (43, 6%) and Cladosporium sp. (23, 2%), were found seven Aspergillus species (4,9%). The most commonly isolated species were Aspergillus versicolor (32,4%) and Aspergillus niger (29,4%). A. niger was isolated only in food storage facilities while A. versicolor was isolated in kitchens, food plating and canteens. Other isolated species were A. flavus, A. ochraceus, A. candidus, A. fumigatus and A. niveus.

Discussion Taking into account what is mentioned in Portuguese Technician Norm NT-SCE-02, presence of

both opportunistic fungi most isolated in air, namely Aspergillus versicolor and Aspergillus niger, shows a lack of air quality in indoor space. Conclusions It was possible to characterize fungal burden concerning Aspergillus species in air of several food units. It was also possible to observe that food units be a possible source of fungal contamination within hospital wards.

Keywords: air, fungal contamination, Aspergillus, food units, hospitals.

1. I

Is well documented that hospital environment is a source of acquired infections (Gammage and Kaye, 1985). For this reason, knowledge of the incidence of microflora in hospitals is important for the understanding of the possible types of infections and allergies that may emanate from them. Furthermore, microbiologic control of hospital environments may play a role in the prevention of cross infection (Ekhaise, Ighosewe and Ajakpovi, 2008).

It is also important to mention the environmental variables that influence air fungal contamination in hospital wards. Previous studies showed that the microbial flora of the indoor air depends on several factors including the number and hygienic standard of people present (Dugid, 1946) the quality of the hospital system (Fink et al., 1971; Fraser et al., 1977; Pickering et al., 1976; Dutkiewicz and Augustowska, 2006), and also food brought to hospital wards (Sarfati, Jensen and Latgé, 1996).

Fungal exposure in hospitals is of particular interest due to the possible patient’s susceptibility. Effects due to fungal exposure are dependent on the species present, the metabolic products, the concentration and exposure duration, and also individual susceptibility (Goyer et al., 2001). Despite the possibility of adverse health effects due to exposure to fungal products, no health-based exposure limits have yet been proposed. In part this is due to the difficulty of accurately characterizing cumulative fungal spore concentrations (Bartlett et al., 2004) and also because, until now epidemiological studies have failed to establish a causal relationship of the extent of fungal presence, exposure time and specific effects on health or frequency and severity of symptoms reported. Studies tend to show only existence of a link between exposure to fungi and development of symptoms, especially respiratory symptoms (Goyer et al., 2001). Attempts have been made only to identify fungi responsible for specific symptoms, such as allergenic (Cruz et al., 1997), inflammatory (Rylander et al., 1992) or mycotoxic (Hodgson et al., 1998) attributed to mold exposures.

However, is well known that invasive aspergillosis is usually acquired by inhalation of conidia, and prevention consists mainly of the use of laminar-airflow rooms for patients at high risk (Arnow et al., 1991; London et al., 1996; Sherertz et al., 1987). Nevertheless, Aspergillus species are frequently present on food and thus can be an indirect source of airway or digestive tract colonization (Sarfati, Jensen and Latgé, 1996), and because of that, their presence in hospital air needs attention (Lugauskas, 2004).

Therefore, it is important to contribute to the increase of knowledge referring air fungal contamination in hospitals indoor spaces, such as food units, in order to identify most effective preventive measures to avoid such contamination. This investigation was designed to describe environmental air fungal contamination by Aspergillus species in ten hospitals food units from Lisbon.

2. M

M

A descriptive study was developed to monitor air fungal contamination in ten hospitals food units from Lisbon. Fifty air samples of 250 litres were collected through impaction method using malt extract agar with chloramphenicol as a bacteria growth inhibitor (MEA). Air samples were collected at 140 L/minute and at one meter tall, in food storage facilities, kitchen, food plating, canteen and also, outside premises, since this was the place regarded as reference. Subsequently, samples were incubated at 27 ºC for 5 to 7 days. After laboratory processing and incubation of the collected samples, quantitative (CFU/m3_{) and qualitative}

results were obtained, with identification of isolated fungal species. Whenever possible, filamentous fungi were identified to the species level, since adverse health effects vary according to fungal species (Rao, Burge and Chang, 1996; Hoog et al., 2000). Identification of filamentous fungi was carried out on material mounted in lactophenol blue and achieved through morphological characteristics listed in illustrated literature (Hoog et al., 2000). Yeasts were identified through biochemical API test (Ghannoum et al., 2000). With the obtained data, tables with frequency distribution of isolated Aspergillus species were made.

3. R

D

Thirty two species of fungi were identified in air. Aspergillus species (4,9%) were not the most frequent, being the two most commonly isolated Penicillium sp. (43, 6%) and Cladosporium sp. (23, 2%). Regarding yeasts, only Rhodotorula sp. (84,2%) and Trichosporon sp. (15,8%) were isolated. There was coincidence between prevailing genera in interior and outside premises, however all ten food units presented fungal species different from the ones isolated outside. Besides that, nine food units presented more CFU/m3 _in

indoor than outdoor premises. Nine of the ten food units presented Aspergillus species and the two most commonly species isolated were Aspergillus versicolor (32,4%) and Aspergillus niger (29,4%) (Table I).

Table 1: Most frequent Aspergillus species identified

Aspergillus species Frequency (%)

Aspergillus versicolor 32,4 Aspergillus niger 29,4 Aspergillus flavus 11,8 Aspergillus ochraceus 8,8 Aspergillus candidus 8,8 Aspergillus fumigatus 5,9 Aspergillus niveus 2,9

A. niger was isolated only in food storage facilities, while A. versicolor was isolated in kitchens, food plating and canteens.

3.1. Discussion

Hospital-wide surveillance studies have shown the presence of various potentially pathogenic fungal species in health care settings (Sarica et al., 2002), and the analyzed hospitals food units were not exception.

It is suggested that fungal levels found indoors should be compared, quantitatively and qualitatively, with those found outdoors, because the first are dependent on the last (Goyer et al., 2001). Nevertheless, when it comes to fungal levels, it should be taken into account that indoor and outdoor environments are quite different which, by itself, justifies diversity of species between different spaces. However, the fact that there is no stipulated limit, with regard to fungal contamination, makes it essential to compare fungal levels indoors and outdoors. Thus, indoor air quality that is significantly different from that outside could mean that there are infiltration problems and the potential risk for health effects exists. It is worth mentioning that as outdoor air is a major source of the fungi found indoors, it is no coincidence that, in this case, the prevailing genera, Penicillium sp. and Cladosporium sp., are the same in both these environments (Nevalainen, 2007). Nonetheless, all ten food units monitored had one or more spaces with fungal species that differed from the ones isolated outside, and also nine of them presented more CFU/m3_{in indoor than}

outdoor air, suggesting, both situations, fungal contamination from within.

Despite in our study Penicillium and Cladosporium genus were the most isolated, Aspergillus was the most common fungi isolated in other international studies concerning hospital wards (Ekhaise, Ighosewe and Ajakpovi, 2008; Jaffal et al., 1997). In the study of Sudharsanam et al., (2008) the commonest fungi isolated from the wards of the three sampled hospitals were Aspergillus niger and Aspergillus flavus and thought these fungi were seen in few numbers, like in our study, their mere existence in the hospital air is of concern, because Aspergillus sp. are known to cause children allergic reactions as well as opportunistic infections, especially in immunocompromised patients (Lugauskas, 2004).

Concerning to the qualitative assessment of fungal contamination, it is suggested that, among other species, Aspergillus fumigatus and Aspergillus versicolor, both of them isolated in the present study, should be regarded as indicators of humidity problems and/or a potential risk to health (Goyer et al., 2001).

Moreover, according to the American Industrial Hygiene Association (AIHA), in 1996, regarding the determination of biological contamination in environmental samples, the confirmed presence of the species A. versicolor, A. flavus and A. fumigatus requires implementation of corrective measures (AIHA, 1996). Confirmed presence of these species occurs when several colonies in different samples, several colonies in a single sample or even a single colony in a single sample, showing the growth of these species in construction materials, are verified. In the present study, the three Aspergillus species mentioned above were identified in the analyzed food units.

Taking into account what is mentioned in Portuguese Technician Norm NT-SCE-02, presence of both opportunistic fungi most isolated in air, namely Aspergillus versicolor and Aspergillus niger, shows a lack of air quality in indoor space. Aspergillus versicolor was isolated in kitchens, food plating and canteens, whereas Aspergillus niger was isolated only in food storage facilities. These can be explain by the effect of environmental variables influencing fungal spreading, namely occupants number (Scheff et al., 2000), environmental variables such as relative humidity (Arundel et al., 1986) and temperature (Kakde, Kakde and Saoji, 2001), as well the developed activities that may also affect fungal concentration (Buttner and Stetzenbach, 1993).

Concerning data obtained from the study, we conclude that surveillance strategies allows the knowledge of environmental air fungal contamination, control of maintenance and cleaning procedures, leading to the education of healthcare workers regarding infection control protocols, and the definition of acceptable levels of contamination in hospitals wards in order to introduce immediate corrective measures (Lebeau et al., 1998; Brocard-Lemort, 2000).

4. C

It was possible to characterize fungal burden, especially concerning Aspergillus species in air of several food units. It was also possible to observe that food units can be a possible source of fungal contamination within hospital wards.

5. R

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