Santi Delia

Legionella spp., amoebae and not-fermenting Gram negative bacteria in an Italian university hospital water system

INTRODUCTION In hospital and other health care facilities, contamination of water systems by potentially infectious microorganisms, such as bacteria, viruses and protozoa, is a source of nosocomial infections, which may originate fromcolonization of water pipes, cooling towers, spa pools, taps, showers and water supplies. Objective. The study focuses on the occurrence of Legionella spp., free-living amoebae and non-fermenting Gram-negative microorganisms in a University hospital water system located in the town of Messina (Sicily, Italy), which had never been examined previously. MATERIALS AND METHODS From January 2008 - March 2009, hot tap water samples were collected from 10 wards. Legionella spp. recovered on selective culture medium were identified by microagglutination latex test; free-living amoebae were cultured using Escherichia coli as a food source. Non-fermenting Gram negative microorganisms were identified by API 20 NE strips. RESULTS Legionella spp. were found in 33.33% of the samples. L. pneumophila serogroup 1 was recovered from the Laboratory Diagnostic and Anaesthesia-Neurology Wards, with a peak of 3.5 × 10(4) cfu/L in May 2008. L. pneumophila serogroups 2-14 were found in the Othorhinolaryngology, Pathologic Anatomy, Paediatrics and Surgery Wards, and peaked (4 × 10(4) cfu/L) in April 2008. Pseudomonadaceae and Hyphomycetes were also detected. Legionella spp. were recovered from samples positive for non-pathogenic amoebae Hartmannella spp. CONCLUSION This first study of a Messina hospital water system suggested potential health risks related to the detection of Hartmannella spp., as reservoirs for Legionella spp., and Pseudomonas aeruginosa, a Gram negative non-fermenting bacterium frequently causing nosocomial pneumonia. The urgent need for monitoring programmes and prevention measures to ensure hospital water safety is stressed.

Serological and molecular identification of Legionella spp. isolated from water and surrounding air samples in Italian healthcare facilities

BACKGROUND Legionella is an intracellular microorganism living in natural and artificial aquatic environments. Although its transmission to humans is linked to the inhalation of contaminated aerosols, there is no validated air sampling method for the control and prevention of the disease. The aim of the present study was to provide more information on the distribution of Legionella spp. in indoor environments and to determine whether the same Legionella strains are isolated from air and water samples. METHODS Ten healthcare facilities located in seven regions of Italy were enrolled. The serological typing of Legionella spp. from water samples and the surrounding air by active and passive sampling was assessed using polyvalent and monovalent antisera. Subsequently, the strains identified as Legionella pneumophila (Lpn) underwent molecular typing by sequence-based typing (SBT) using seven genes (flaA, pilE, asd, mip, mompS, proA, and neuA). The allelic profile number was assigned using the European Working Group for Legionella Infections-SBT database. RESULTS Lpn serogroup 6 was the most prevalent serogroup; it was found simultaneously in the air and water samples of three different healthcare facilities. In the remaining seven hospitals, Lpn serogroups 1, 6, 7, 9, and 12 were isolated exclusively from water samples. The molecular investigation showed that Lpn strains in the water and air samples of each positive healthcare facility had the same allelic profile. Strains, identified as sequence types (STs) 728 and ST 1638+ST 1324, were isolated in two respective healthcare facilities, and a new strain, identified as ST 1989, was obtained in one healthcare facility. CONCLUSION The application of the SBT method allowed to verify the homology among Legionella strains from water samples and the surrounding air. The results showed that the same Lpn strains were present in the air and water samples, and a new Legionella strain was identified.

Evaluation of Legionella Air Contamination in Healthcare Facilities by Different Sampling Methods: An Italian Multicenter Study

Healthcare facilities (HF) represent an at-risk environment for legionellosis transmission occurring after inhalation of contaminated aerosols. In general, the control of water is preferred to that of air because, to date, there are no standardized sampling protocols. Legionella air contamination was investigated in the bathrooms of 11 HF by active sampling (Surface Air System and Coriolis®μ) and passive sampling using settling plates. During the 8-hour sampling, hot tap water was sampled three times. All air samples were evaluated using culture-based methods, whereas liquid samples collected using the Coriolis®μ were also analyzed by real-time PCR. Legionella presence in the air and water was then compared by sequence-based typing (SBT) methods. Air contamination was found in four HF (36.4%) by at least one of the culturable methods. The culturable investigation by Coriolis®μ did not yield Legionella in any enrolled HF. However, molecular investigation using Coriolis®μ resulted in eight HF testing positive for Legionella in the air. Comparison of Legionella air and water contamination indicated that Legionella water concentration could be predictive of its presence in the air. Furthermore, a molecular study of 12 L. pneumophila strains confirmed a match between the Legionella strains from air and water samples by SBT for three out of four HF that tested positive for Legionella by at least one of the culturable methods. Overall, our study shows that Legionella air detection cannot replace water sampling because the absence of microorganisms from the air does not necessarily represent their absence from water; nevertheless, air sampling may provide useful information for risk assessment. The liquid impingement technique appears to have the greatest capacity for collecting airborne Legionella if combined with molecular investigations.

Chemistry and Hygiene of Food Additives

Chemistry and hygiene of food additives. , Chemistry and hygiene of food additives. , کتابخانه دیجیتالی دانشگاه علوم پزشکی و خدمات درمانی شهید بهشتی

Bacterial isolates from the Arctic region (Pasvik River, Norway): assessment of biofilm production and antibiotic susceptibility profiles

Bacterial biofilm production is recognized as a strategy that helps aquatic bacteria in resisting to the presence of several kinds of pollutants, including antibiotics, in the bulk environment. The Pasvik River, located between Norway, Russia and Finland, is a sub-Arctic site polluted by wastes from metallurgic and mining activities. In order to study whether and to what extent bacteria are able to produce biofilms, and to assess whether this physiological characteristic influences their resistance to antibiotics, an investigation was performed on bacteria isolated from water and sediment collected along the Pasvik River course during two surveys (May and July). Bacterial strains were screened for their biofilm production and profiles of susceptibility to antibiotics. Results showed that biofilm formation was a widespread characteristic of the isolates. Most of them were also resistant to several antibiotics, such as ampicillin (100% of the isolates) as well as cefazolin, cefoxitin, ceftriaxone, mezlocillin, nitrofurantoin and sisomicin (90% of the total strains). This study shows a significant association between biofilm formation and antibiotic resistance at inner stations both in water and in sediments in May only. This suggests that in Pasvik River colder temperature may stimulate bacterial aggregation into biofilm and simultaneously decrease bacterial susceptibility to antibiotics; since the occurrence of antibiotic resistance has frequently been linked to the presence of pollutants, this result could represent a strategy of bacterial survival under altered environmental conditions.

Use and Overuse of Food Additives in Edible Products: Health Consequences for Consumers

The aim of this chapter was to address the issue of uses and overuses of additives with consequent impacts on human health. Modern food additives have an important role in food production. At present, the number of individuals engaged in food primary production is dramatically decreasing; on the other hand, consumers seems to search for many food choices, including ready-to-eat foods, with annexed higher safety and hygiene standards (and food additives may be a concern). The most part of consumers have still confidence in the work of official commissions in defense of food safety; on the other hand, some people may find deem discrepancies between their own sense of security and the complex of laws or practices in defense of the human health. Main worries concern the enormous economic power of certain multinational groups in the field of food production; the absolute discretion of Committees to judge eligible or not eligible available researches on certain food additives; the choice of research methods and the lack of studies concerning synergist effects of different food additives.

Food Additives and Effects on the Microbial Ecology in Yoghurts

The aim of this study was to describe the current use of selected food additives in the dairy sector, particularly with relation to the production of yoghurt products. The modern production of yoghurt is performed by means of controlled processes and the careful selection of ingredients in addition to bovine milk: milk powder, sugar, fruit and bacterial starter cultures, flavourings, colour agents, emulsifiers, and stabilisers. These substances are grouped under the name of food additives. The use of certain additives, especially sweeteners, dyes and thickening agents, has been discussed here with relation to peculiar yoghurt categories which can represent the current situation of the whole market in terms of global sales and consumers’ preferences.

Classification and Technological Purposes of Food Additives: The European Point of View

The aim of this chapter was to describe the regulatory classification and the list of ‘technological purposes’ of food additives by the European viewpoint. At present, food additives are extremely useful. Significant progress has been made in the field of health and nutrition. Food additives play an important role in the complex chain of modern food productions. In general, foods are subject to many environmental variables which may alter the original composition. Moreover, the presence of additives in foods must be declared on the label as an ingredient. Also, all additives used in the food industry are included in a ‘positive list’ by health organisations. Finally, food additives are classified into functional categories, in relation to the declared action: food protection, colour or flavour enhancement, sugar substitution or structural and technological functions. This chapter provides also a description of these sub-categories with correlated examples.

The Codex Alimentarius and the European Legislation on Food Additives

The aim of this Chapter is to give an overview of International principles concerning food additives with a description of the related European legislation. Basically, the matter of food additives may be discussed on a large-scale level by means of the description of the ‘General Standards for Food Additives’ (Codex Alimentarius Commission), a harmonised, workable and indisputable international standard. On the other hand, the European viewpoint has to be considered: main Regulations concerning food additives have been discussed. The EU Legislation and Codex Alimentarius have very similar regulations about food additives, sometimes using the same definitions. This situation shows a general trend in the international harmonisation of technical legislation in many law fields. However, some difference has to be highlighted, including the legal validity. In fact, Codex Alimentarius documents have established a sort of general principle that has to be adopted by domestic laws to become effective. In contrast, European Union Regulations are legally mandatory for all Member states of the Union after their official publication and national translation.

Comparative Study of Antibacterial and Haemolytic Activities in Sea Bass,European Eel and Blackspot Seabream

Sea bass (Dicentrarchus labrax, Moronidae), European eel (Anguilla anguilla, Anguillidae) and blackspot seabream (Pagellus bogaraveo, Sparidae) were studied to check their mucus, blood sera and tissue samples for antibacterial and agglutinating activity against a variety of Gram negative and positive bacteria. Samples were also examined for their haemolytic properties against sheep red blood cells. The highest antibacterial activity was detected in the blood sera of blackspot seabream and European eel (against Vibrio alginolyticus) and in the kidneys of sea bass (against Photobacterium damselae subsp. piscicida). Haemolytic properties against sheep red blood cells were observed in the mucus of sea bass and blackspot seabream, as well as in the sera of eel and sea bass. The sera of sea bass and eel showed also agglutinating activity against Pseudomonas aeruginosa and Staphylococcus aureus; the mucus of sea bass was able to agglutinate isolates of Vibrio fluvialis, V. alginolyticus and A. hydrophila. The study suggested that the mucus secretions, biological fluids and organs of the examined fish species can be regarded as an interesting source of bioactive compounds with antibacterial and haemolytic properties.