Bacterial ghosts (BG) are empty cell envelopes derived from Gram-negative bacteria. They contain many innate immunostimulatory agonists, and are potent activators of a broad range of cell types involved in innate and adaptive immunity. Several considerable studies have demonstrated the effectiveness of BG as adjuvants as well as their ability to induce proinflammatory cytokine production by a range of immune and non-immune cell types. These proinflammatory cytokines trigger a generalized recruitment of T and B lymphocytes to lymph nodes that maximize the chances of encounter with their cognate antigen, and subsequent elicitation of potent immune responses. The plasticity of BG has allowed for the generation of envelope-bound foreign antigens in immunologically active forms that have proven to be effective vaccines in animal models. Besides their adjuvant property, BG also effectively deliver DNA-encoded antigens to dendritic cells, thereby leading to high transfection efficiencies, which subsequently result in higher gene expressions and improved immunogenicity of DNA-based vaccines. In this review, we summarize our understanding of BG interactions with the host immune system, their exploitation as an adjuvant and a delivery system, and address important areas of future research interest.

There is limited information available on the association between Enterocytozoon bieneusi and diseases in animals or on the characteristics of the strains involved. This study examined the occurrence of E. bieneusi in piglets with and without diarrhea to determine its involvement. Among 472 fecal samples from 472 piglets (237 with diarrhea and 235 without) up to 7 weeks of age, 67 (approximately 14%) were polymerase chain reaction (PCR) positive for E. bieneusi. Of the 237 piglets with diarrhea, 38 (approximately 16%) tested positive for E. bieneusi. Of the 235 healthy piglets, 29 (approximately 12%) tested positive for E. bieneusi. This species was detected only in the younger group of piglets with diarrhea, particularly those aged less than 1 week and between 1 and 2 weeks. This suggests that E. bieneusi is a possible cause of diarrhea in piglets. This organism, however, produced asymptomatic infections in the older piglets, as there was no significant difference in the rates of occurrence between the diarrheic and nondiarrheic older piglets (aged older than 4 weeks). The internal transcribed spacer (ITS) region of the ribosomal ribonucleic acid gene of the ten E. bieneusi-positive samples was amplified using nested PCR and subsequently sequenced. Genetic polymorphisms, which were represented by five distinct genotypes (PEbA-PEbE), were found among the E. bieneusi isolates. The five genotypes identified in this study differed from each other by two to six single-nucleotide polymorphisms. Nine isolates from four genotypes (PEbA-PEbD) were homologous to previously known types that had originally been isolated from pigs. However, one isolate from the PEbE genotype was identical to type CAF1, which was originally isolated from humans. In addition, the phylogenetic relationships determined by the neighbor-joining analysis of the ITS sequences indicated this genotype to be more distant from the other pig-specific genotypes. Thus, this isolate from pigs may be distantly related to the pig-specific genotypes and may be capable of infecting humans.

Bacterial ghosts (BGs) are empty cell envelopes derived from Gram-negative bacteria by bacteriophage ɸX174 gene E mediated lysis. They represent a novel inactivated vaccine platform; however, the practical application of BGs for human vaccines seems to be limited due to the safety concerns on the presence of viable cells in BGs. Therefore, to improve the lysis efficiency of the gene E, we exploited the peptidoglycan hydrolyzing ability of the λ phage holin-endolysins to expedite the process of current BG production system. In this report, we constructed a novel ghost plasmid encoding protein E and holin-endolysins in tandem. We observed that sequential expressions of the gene E and the holin-endolysins elicited rapid and highly efficient Salmonella lysis compared to the lysis mediated by gene E only. These lysed BGs displayed improved immunogenicity in mice compared to the gene E mediated BGs. Consequently, seventy percent of the mice immunized with these novel ghosts survived against a lethal challenge while all the mice vaccinated with gene E mediated ghosts died by day 9 post-infection. We conclude that this novel strategy has the potential to generate highly efficient inactivated candidate vaccines that could replace the currently available bacterial vaccines.

In agricultural intensive areas, drinking contaminated water from private wells is considered an important cause of acute gastroenteric illnesses (AGI), particularly among high-risk populations. In the summer of 2009, the microbial water quality of 180 randomly selected private wells in two northeastern Ohio counties, a region with a high concentration of dairy farms, was assessed. Forty-five percent (82/180) of water samples were contaminated with total coliforms. Generic Escherichia coli were present in 9% (16/180) of samples. Using real-time polymerase chain reaction, E. coli O157:H7 was identified in 4% (7/180) of specimens. Campylobacter spp. DNA could not be amplified from 70 of the samples tested for this organism. The frequency of generic E. coli contamination varied among townships (P < 0.001). Well structure (i.e. age and depth) or other common measures of pollution potential (depth of water, hydrology, topography, net recharge soil media) was not correlated with coliforms and E. coli contamination. Importantly, the presence of the pathogen E. coli O157:H7 was not associated with the presence of fecal indicators in the water samples: Only one of the seven E. coli O157-positive samples was also positive for generic E. coli. Appropriate risk management and communication processes are needed to reduce the potential waterborne disease outbreaks in agricultural intensive areas.

The colibacillosis caused by avian pathogenic (APEC) is responsible for a significant loss of productivity and mortality in the poultry industry. The pathogenicity of these bacteria is based on the presence and expression of various virulence factors. In this study, the presence of the virulence-associated genes in APEC was determined using PCR. Among the isolates from the chickens with colibacillosis, all contained at least one of the genes as approximately of the isolates contained Interestingly, the gene, which has not been detected in APEC previously, was detected in half of the isolates. The ColV plasmid-associated genes such as genes were also detected in. ,. ,. ,. ,. and. of isolates, respectively. With regard to the fimbrial genes, the (.), papC (.) and genes (.) were identified at relatively low rates, none of the isolates harbored or and only of the isolates (.) contained In this study, isolates harbored two or more of the genes, and there were di erent patterns of gene combination in the isolates. The most common pattern, which was found in. (isolates), was Overall, these results suggest that APEC strains in this area commonly contain multiple virulence factors and approximately half of the APEC strains contained the ColV plasmid-associated genes. Especially, and were detected more than half of the isoaltes. : APEC, broilers, molecular detection, virulence genes tsh fyu irp