Outbreak of acute gastroenteritis in an air force base in Western Greece

BACKGROUND: On the 20(th )September 2005, soldiers and staff at the Air Force base in Western Greece experienced an outbreak of acute gastroenteritis. The purpose of this study was to identify the agent and the source of the outbreak in order to develop control measures and to avoid similar outbreaks in the future. METHODS: A case-control analytical approach was employed with 100 randomly selected cases and 66 controls. Patients completed standardized questionnaires, odds ratios were calculated and statistical significance was determined using χ(2 )test. In addition, to identify the source of the infection, we performed bacteriological examination of food samples (included raw beef, cooked minced meat, grated cheese and grated cheese in sealed package) collected from the cuisine of the military unit. RESULTS: More than 600 out of the 1,050 individuals who ate lunch that day, became ill. The overall attack rate, as the military doctor of the unit estimated it, was at least 60%. The overall odds ratio of gastroenteritis among those who had lunch was 370 (95% CI: 48–7700) as compared to those who didn't eat lunch. Among the symptoms the most prominent were watery diarrhoea (96%) and abdominal pain (73%). The mean incubation period was 9 h and the median duration of the symptoms was 21 h. In the bacteriological examination, Staphylococcus aureus was detected in a sample of raw beef (2,000 cfu per g) and in two samples of grated cheese; leftover cheese from lunch (7,800 cfu per g) and an unopened package purchased from the market (3,000 cfu per g). CONCLUSION: The findings of this study suggest that the aetiological agent of this outbreak was S. aureus. The food vehicle was the grated cheese, which was mixed with the beef and served for lunch in the military unit. This outbreak highlights the capacity of enterotoxin-producing bacteria to cause short term, moderately-severe illness in a young and healthy population. It underscores the need for proper food handling practices and reinforces the public health importance of timely notification of such outbreaks

Synthesis and Characterization of Cerium Oxide Nanoparticles: Effect of Cerium Precursor to Gelatin Ratio

Hemocompatible nanoparticles with reactive oxygen species (ROS) scavenging properties for titanium implant surface coatings may eliminate implant failure related to inflammation and bacterial invasion. Cerium (Ce) is a rare earth element, that belongs to the lanthanide group. It exists in two oxidation states, Ce+3 and Ce+4, which contribute to antioxidant, catalytic, antibacterial, and ROS-scavenging properties. The purpose of the present study was to synthesize ceria nanoparticles and to evaluate their hemocompatibility and ROS scavenging properties. The synthesis of Ce-NPs was performed via the sol-gel method, and five different ratios of cerium precursors to gelatin were evaluated. Their characterization was achieved through FTIR, XRD, SEM, and TEM. Hemocompatibility and ROS analysis were evaluated at different concentrations with human erythrocytes. The morphology and size distribution were certified by TEM and the cubic CeO2 fluorite structure was identified by selected area electron diffraction and high-resolution TEM. The particle size of the lowest Ce concentration presented a mean diameter of 10 nm. At concentrations of 2 NPs unique candidates as nanofillers or nanocoatings with antibacterial properties

Differentiation of faecal Escherichia coli from humans and animals by multiple antibiotic resistance analysis

Summarization: Aims:  Multiple antibiotic resistance (MAR) was performed on 128 Escherichia coli isolates, recovered from faecal samples of humans and animals (cattle, goat, sheep) to determine and compare their antibiotic resistance patterns and to evaluate them statistically in order to specify the source of the faecal material. Methods and Results:  Disk diffusion method was applied with a selection of antibiotics. Statistical approach was performed with hierarchical cluster analysis (CA), discriminant analysis (DA) and principal component analysis. Comparing human and animal isolates there was significant difference in levels of resistance to all antibiotics tested (P < 0·05) with 46 and 24 distinct resistance patterns for human and animal isolates respectively. CA and DA separated human and animal isolates with a high average rate of correct classification (99·2%), when all animal isolates were pooled together. Conclusions:  MAR analysis compared with appropriate statistical evaluation may provide a useful tool for differentiating the human or animal origin of E. coli isolates derived from environmental samples. Subsequently, determination of the source of faecal pollution becomes possible. Significance and Impact of the Study:  Determining the source of faecal pollution enables the prediction of possible risk for public health and the application of appropriate management plans for prevention of further contamination.Presented on: Letters in Applied Microbiolog

Development of a multiplex PCR detection of Salmonella spp. and Shigella spp. in mussels

Summarization: Multiplex PCR amplification of invA and virA genes was developed enabling simultaneous detection in mussels of Salmonella spp. and Shigella spp., respectively. Simultaneous amplification of products of 215 and 275 bp was obtained either by using mixtures of individual strains of Sh. dysenteriae and Salm. typhimurium or spiked contaminated mussels with both bacteria. In the case of the mussels, 10-100 cells of Salmonella spp. and Shigella per millilitre of homogenate were detected by the multiplex PCR following a pre-enrichment step to increase sensitivity and to ensure that detection was based on the presence of cultivable bacteria. Also, the sensitivity and specificity of this method was evaluated. Multiplex PCR amplification was shown to be an effective, sensitive and rapid method for the simultaneous detection of pathogens in mussels.Παρουσιάστηκε στο: Letters in Applied Microbiolog

Microbiological evaluation of bottled non-carbonated ("still") water from domestic brands in Greece

Summarization: The microbiological quality of 1527 samples of bottled noncarbonated (‘still’) mineral water, purchased from retail outlets and derived from 10 manufacturing companies in Greece, was investigated during the period 1995–2003. Applying the membrane filter technique, the aliquots of water samples (250 ml) were analyzed for the presence and enumeration of total coliforms, Escherichia coli, Enterococcus spp. and Pseudomonas aeruginosa. Also, aerobic bacteria were counted as Heterotrophic Plate Count (HPC) ml− 1 at 22 and 37 °C. Positive samples for the parameters tested varied significantly among brands with an overall percentage of 13.95% bottled water samples noncompliant with the Greek water regulation. Microorganisms isolated from the samples tested were identified as species of Pseudomonas, Aeromonas, Pasteurella, Citrobacter, Flavobacterium, Providencia and Enterococcus. The most frequent isolated microorganism during the period of the study was P. aeruginosa. Generally, bacterial load of the samples tested ranged in low levels. The purpose of the current study was to evaluate the microbiological quality of the bottled water provided by domestic brands in the Greek market during the period 1995–2003.Presented on: International Journal of Food Microbiolog

Hybridisation of F+ RNA coliphages detected in shellfish samples with oligonucleotide probes to assess the origin of microbiological pollution of shellfish

Summarization: Current measures for controlling the public health risks associated with bivalve molluscan shellfish consumption rely on the use of Escherichia coli to indicate the sanitary quality of shellfish harvesting areas. However, it has been demonstrated that E. coli is an inadequate indicator of the viral risk associated with shellfish. An alternative indicator, male-specific B+ coliphages, have been investigated as viral indicators of faecal contamination that may provide source-specific information for impacted environmental waters. This study compared the distribution of E. coli and F+ RNA bacteriophages in shellfish grown in harvesting areas of Greece and also examined the presence and proportions of the different subgroups of F+ RNA coliphages in shellfish. F+ RNA bacteriophages were present in shellfish at higher concentrations than E. coli. Elevated numbers of F+ RNA bacteriophages observed in the winter concur with the known increased viral risk associated with shellfish harvested at that time of year in Greece. The majority of F+ RNA coliphages detected in shellfish samples belonged to group IV which indicated the possible presence of animal faecal material in sample harvesting areas. Phages of groups II and III (human waste and human faecal material, respectively) were present at low levels. Finally, 8% of the phages hybridised were found to belong to group I. The presence of group IV showed seasonal distribution (more in winter, less in summer) whereas the other groups did not show any difference. Monitoring of F+ coliphage subgroups may indicate the presence and major sources of microbial inputs to surface waters; however, environmental effects on the relative occurrence of different groups need to be considered.Presented on: Water Science and Technolog