Josef Kleer

Arcobacter butzleri Induces Barrier Dysfunction in Intestinal HT-29/B6 Cells

BACKGROUND Arcobacter butzleri causes watery diarrhea and bacteremia. Although, recently, more cases of diarrhea have been caused by Arcobacter species, very little is known about its pathogenesis, the identification of which is the aim of this study. METHODS Human HT-29/B6 colonic epithelial monolayers were apically inoculated with A. butzleri. Transepithelial resistance and macromolecule fluxes were measured in Ussing chambers. Tight junction protein expression was analyzed by Western blotting, and subcellular distribution was analyzed by confocal laser-scanning microscopy. RESULTS Infection of HT-29/B6 caused a decrease in transepithelial resistance to 30% and an increase in paracellular permeability to fluorescein (10.8+/-3.5 10(-6) cm/s vs. 1.8+/-0.6 10(-6) cm/s in control; P<.05) and dextran-4 kDa (0.036+/-0.005 10(-6) cm/s vs. 0.015+/-0.002 10(-6) cm/s in control; P<.01). This effect was time and dose dependent and was also caused by bacterial lysates showing heat and proteinase-K sensitivity. As structural correlate, expression of the tight junctional proteins claudin-1, -5, and -8 was reduced, and claudin-1 and -8 were redistributed off the tight junctional strands forming intracellular aggregates. Furthermore, A. butzleri induced epithelial apoptosis (3-fold). CONCLUSIONS A. butzleri induces epithelial barrier dysfunction by changes in tight junction proteins and induction of epithelial apoptosis, which are mechanisms that are consistent with a leak flux type of diarrhea in A. butzleri infection.

Prevalence and antimicrobial susceptibility of Listeria monocytogenes on chicken carcasses in Bandung, Indonesia.

This study was conducted to determine the prevalence and quantify the number of Listeria monocytogenes in fresh chicken carcasses sold in traditional markets and supermarkets in Bandung, West Java, Indonesia, and to determine the antimicrobial resistance patterns of the isolated L. monocytogenes strains. The overall prevalence of L. monocytogenes in chicken carcasses was 15.8% (29/184). When comparing samples from traditional markets and supermarkets, no significant difference in the L. monocytogenes prevalence was detectable (15.2 versus 16.3%). Of the samples, 97.3% had L. monocytogenes counts <100 CFU/g, 2.2% had L. monocytogenes counts between 101 and 1,000 CFU/g, and 0.5% had L. monocytogenes counts of 1,001 to 10,000 CFU/g. Of the isolates, 27.6% were resistant to at least one of the 10 antimicrobials tested, with the major resistant phenotypes to penicillin (17.2%), ampicillin (6.9%), and erythromycin (6.9%). All 29 isolates recovered in this study were grouped into the molecular serogroup IIb, comprising the serovars 1/2b, 3b, and 7.

Microbiological and chemical investigation of caviar at retail

Within the last decade caviar has become a food with a growing customer range, mainly due to raised production of salmon and trout caviar. Another reason might be the raised stability because of preservatives and pasteurization which enables transportation over long distances. Since microbiological criteria are lacking, the estimation of eligibility of caviar is not easily achieved. The aim of the recent study was to analyze nonsturgeon caviar according to microbiological and organoleptic levels. Thus, 50 caviar samples from retail were tested. Organoleptic deviations were found in many samples (64 %), even though adequate microbiological quality was ensured. In 46 % of samples investigated, elevated bacterial loads of mesophilic aerobic counts over 2 log CfU/g were found. However, only single samples contained high microbial loads[6 log CfU/g. Moreover, the presence of potentially pathogenic bacteria, Mycobacterium spp., was detected.

Uptake and Localization of Vibrio cholerae, Vibrio parahaemolyticus, and Vibrio vulnificus in Blue Mussels (Mytilus edulis) of the Baltic Sea

ABSTRACT Species of Vibrio can persist in blue mussels, especially when they are present in high numbers as a result of a large uptake from the aquatic environment. This study investigated the uptake, localization, and persistence of three Vibrio species relevant to human health in blue mussels (Mytilus edulis) after artificial contamination. Mussels M. edulis were kept in tanks of artificial seawater spiked with Vibrio spp. to monitor bioaccumulation of these bacteria in corresponding bivalves. Bacteria accumulated rapidly in the bivalves, reaching high concentrations after 1.5 h. The highest Vibrio sp. counts were detected in the digestive glands, with 6.9 × 108 cfu/g for Vibrio parahaemolyticus, 1.5 × 107 cfu/g for Vibrio cholerae, and 2.2 × 107 cfu/g for Vibrio vulnificus. Among bivalve compartments, the digestive glands showed the fastest enrichment of Vibrio and maintained the highest Vibrio numbers throughout the examination period. After transfer to a tank containing filtered, sterile seawater, the Vibrio load in bivalves showed a continuous reduction. However, even after 7 days of depuration, an average concentration of approximately 103 cfu/g remained in the digestive glands of M. edulis. In clearance assays, a general clearance rate of 0.02 log cfu/g/h was calculated for all three strains. For the first time, in vivo accumulation counts and clearance kinetics of Vibrio within mussel compartments are shown, highlighting a strong concentration of Vibrio in the digestive glands whereas other tissues continued to accumulate significantly less Vibrio.