Epidemiological, clinical, and public health response characteristics of a large outbreak of diphtheria among the Rohingya population in Cox's Bazar, Bangladesh, 2017 to 2019: A retrospective study.

BACKGROUND: Unrest in Myanmar in August 2017 resulted in the movement of over 700,000 Rohingya refugees to overcrowded camps in Cox's Bazar, Bangladesh. A large outbreak of diphtheria subsequently began in this population. METHODS AND FINDINGS: Data were collected during mass vaccination campaigns (MVCs), contact tracing activities, and from 9 Diphtheria Treatment Centers (DTCs) operated by national and international organizations. These data were used to describe the epidemiological and clinical features and the control measures to prevent transmission, during the first 2 years of the outbreak. Between November 10, 2017 and November 9, 2019, 7,064 cases were reported: 285 (4.0%) laboratory-confirmed, 3,610 (51.1%) probable, and 3,169 (44.9%) suspected cases. The crude attack rate was 51.5 cases per 10,000 person-years, and epidemic doubling time was 4.4 days (95% confidence interval [CI] 4.2-4.7) during the exponential growth phase. The median age was 10 years (range 0-85), and 3,126 (44.3%) were male. The typical symptoms were sore throat (93.5%), fever (86.0%), pseudomembrane (34.7%), and gross cervical lymphadenopathy (GCL; 30.6%). Diphtheria antitoxin (DAT) was administered to 1,062 (89.0%) out of 1,193 eligible patients, with adverse reactions following among 229 (21.6%). There were 45 deaths (case fatality ratio [CFR] 0.6%). Household contacts for 5,702 (80.7%) of 7,064 cases were successfully traced. A total of 41,452 contacts were identified, of whom 40,364 (97.4%) consented to begin chemoprophylaxis; adherence was 55.0% (N = 22,218) at 3-day follow-up. Unvaccinated household contacts were vaccinated with 3 doses (with 4-week interval), while a booster dose was administered if the primary vaccination schedule had been completed. The proportion of contacts vaccinated was 64.7% overall. Three MVC rounds were conducted, with administrative coverage varying between 88.5% and 110.4%. Pentavalent vaccine was administered to those aged 6 weeks to 6 years, while tetanus and diphtheria (Td) vaccine was administered to those aged 7 years and older. Lack of adequate diagnostic capacity to confirm cases was the main limitation, with a majority of cases unconfirmed and the proportion of true diphtheria cases unknown. CONCLUSIONS: To our knowledge, this is the largest reported diphtheria outbreak in refugee settings. We observed that high population density, poor living conditions, and fast growth rate were associated with explosive expansion of the outbreak during the initial exponential growth phase. Three rounds of mass vaccinations targeting those aged 6 weeks to 14 years were associated with only modestly reduced transmission, and additional public health measures were necessary to end the outbreak. This outbreak has a long-lasting tail, with Rt oscillating at around 1 for an extended period. An adequate global DAT stockpile needs to be maintained. All populations must have access to health services and routine vaccination, and this access must be maintained during humanitarian crises.

Microbial contamination of moose (Alces alces) and white-tailed deer (Odocoileus virginianus) carcasses harvested by hunters.

Hunting is currently a very popular activity, and interest in game meat is increasing. However, only limited research is available on the bacterial quality and safety of moose (Alces alces) and white-tailed deer (Odocoileus virginianus) harvested by hunters. Poor hunting hygiene can spread bacteria onto the carcasses, and inadequate chilling of the carcasses may increase the bacterial load on the carcass surface. We studied the bacterial contamination level on carcasses of 100 moose and 100 white-tailed deer shot in southern Finland. Hunters eviscerated carcasses in the field and skinned them in small slaughter facilities. During the sampling, same person visited 25 facilities located in 12 municipalities of four provinces. Moose carcasses had mean mesophilic aerobic bacteria (MAB), Enterobacteriaceae (EB) and Escherichia coli (EC) values of 4.2, 2.6 and 1.2 log10 cfu/cm2, respectively, while deer carcass values were 4.5, 1.5 and 0.7 log10 cfu/cm2, respectively. Moose carcasses were significantly more contaminated with EB and EC than deer carcasses. High bacterial counts (MAB>5.0 log10 cfu/cm2 and EB > 2.5 log10 cfu/cm2) on the carcasses were associated with the smallest facilities having only one room. The outdoor temperature and days between hunting and sampling affected the bacterial counts. High EB counts on the carcasses indicated a gut hit. Male gender was significantly more contaminated by EC and meat-borne pathogenic bacteria: Campylobacter spp., Salmonella spp., enteropathogenic Yersinia spp., stx-harbouring EC (STEC) and Listeria monocytogenes. STEC (28/200) and L. monocytogenes (20/200) were the most commonly detected bacteria by PCR. L. monocytogenes isolates of different sequence types (ST7, 18, 29, 37, 249, 412, 451 and 611) belonged to serotypes 1/2a (seven isolates) and 4b (three isolates). The virulence gene ail was detected in four Yersinia enterocolitica biotype 1A isolates and one Yersinia kristensenii isolate. The bacterial counts on the moose and deer carcasses varied highly, and more attention should be paid to hunting hygiene and training of hunters. Game meat may be a source of meat-borne pathogens, and close attention should therefore be paid when handling and preparing game.

[A domestic human case of hepatitis E in Finland]. / Suomalaismiehen kotoperäinen E-hepatiittitartunta.

We describe the first verified domestic HEV case in a previously healthy 53-year-old man who presented a three-day history of upper stomach pain, nausea, fever, arthralgia and fatigue. At the first phase laboratory tests revealed high levels of AST and ALT and at the second phase high levels of bilirubin. Serum was positive for anti-HEV IgM and for HEV RNA confirming the diagnosis of acute hepatitis E. The HEV was genotype 3. Jaundice resolved in three months. In nonendemic areas autochthonous hepatitis E is more common than previously recognized and is possible in patients with acute hepatitis.

Reduction in mortality from HIV-related CNS infections in routine care in Africa (DREAMM): a before-and-after, implementation study.

BACKGROUND: Four decades into the HIV epidemic, CNS infection remains a leading cause of preventable HIV-related deaths in routine care. The Driving Reduced AIDS-associated Meningo-encephalitis Mortality (DREAMM) project aimed to develop, implement, and evaluate pragmatic implementation interventions and strategies to reduce mortality from HIV-related CNS infection. METHODS: DREAMM took place in five public hospitals in Cameroon, Malawi, and Tanzania. The main intervention was a stepwise algorithm for HIV-related CNS infections including bedside rapid diagnostic testing and implementation of WHO cryptococcal meningitis guidelines. A health system strengthening approach for hospitals was adopted to deliver quality care through a co-designed education programme, optimised clinical and laboratory pathways, and communities of practice. DREAMM was led and driven by local leadership and divided into three phases: observation (including situational analyses of routine care), training, and implementation. Consecutive adults (aged ≥18 years) living with HIV presenting with a first episode of suspected CNS infection were eligible for recruitment. The primary endpoint was the comparison of 2-week all-cause mortality between observation and implementation phases. This study completed follow-up in September, 2021. The project was registered on ClinicalTrials.gov, NCT03226379. FINDINGS: From November, 2016 to April, 2019, 139 eligible participants were enrolled in the observation phase. From Jan 9, 2018, to March 25, 2021, 362 participants were enrolled into the implementation phase. 216 (76%) of 286 participants had advanced HIV disease (209 participants had missing CD4 cell count), and 340 (69%) of 494 participants had exposure to antiretroviral therapy (ART; one participant had missing ART data). In the implementation phase 269 (76%) of 356 participants had a probable CNS infection, 203 (76%) of whom received a confirmed microbiological or radiological diagnosis of CNS infection using existing diagnostic tests and medicines. 63 (49%) of 129 participants died at 2 weeks in the observation phase compared with 63 (24%) of 266 in the implementation phase; and all-cause mortality was lower in the implementation phase when adjusted for site, sex, age, ART exposure (adjusted risk difference -23%, 95% CI -33 to -13; p<0·001). At 10 weeks, 71 (55%) died in the observation phase compared with 103 (39%) in the implementation phase (-13%, -24 to -3; p=0·01). INTERPRETATION: DREAMM substantially reduced mortality from HIV-associated CNS infection in resource-limited settings in Africa. DREAMM scale-up is urgently required to reduce deaths in public hospitals and help meet Sustainable Development Goals. FUNDING: European and Developing Countries Clinical Trials Partnership, French Agency for Research on AIDS and Viral Hepatitis. TRANSLATIONS: For the French and Portuguese translations of the abstract see Supplementary Materials section.

Identification of domestic reservoirs and common exposures in an emerging lineage of Shiga toxin-producing Escherichia coli O157:H7 in England: a genomic epidemiological analysis.

BACKGROUND: The zoonotic pathogen Shiga toxin-producing Escherichia coli (STEC) O157:H7 emerged during the 1980s as a causative agent of foodborne outbreaks associated with haemorrhagic colitis and haemolytic uraemic syndrome, which can be fatal. We investigated the emerging lineage IIc that was causing outbreaks of STEC O157:H7, identified and quantified the domestic and non-domestic reservoirs, and quantified patient exposures across the population of England. METHODS: In this genomic epidemiological analysis study, all human STEC O157:H7 lineage IIc (n=925) isolates cultured from faecal specimens submitted to the UK Health Security Agency between June 1, 2015, and Dec 31, 2020, from patients in England in the community or in hospital, were whole-genome sequenced and the genomic population structure was described. Explanatory variables were obtained from microbiological surveillance data and STEC Enhanced Surveillance Questionnaire responses. Ancestral-state reconstruction using patient travel information was used to define domestic and non-domestic clades and transmission dynamics. Exposures for patients infected with isolates from domestic clades were assessed using mixed-effects multinomial univariable and multivariable regression. FINDINGS: Lineage IIc emerged 50 years ago, and subsequent clonal expansions have resolved into six major extant clades. We defined two English domestic clades that emerged during the past 30 years, and four non-domestic clades comprising isolates that infected or were transmitted to patients in England via international travel or the consumption or handling of imported food. Throughout the study period, non-domestic clades contributed approximately twice the number of infections as domestic clades did. Patients infected with domestic IIc clade strains reported more frequent exposure to fresh produce (raw vegetables p=0·012; prepackaged salad p=0·0009), contact with animals (cattle p=0·021), and visits to farms (p=0·0053) than patients infected with strains from other STEC O157:H7 lineages. A multivariable mixed-effects multinomial model confirmed that within the domestic clades, the major risk factors for infection were prepackaged salad (clade 2.3.3, relative risk ratio [RRR] 1·72, 95% CI 1·09-2·72; p=0·019) and visits to farms (clade 2.5.2, RRR 1·98, 1·12-3·52; p=0·020) as fixed effects. Local authority district as a random variable had a strong but variable effect for clades 2.3.3 and 2.5.2. INTERPRETATION: Lineage IIc has emerged as the most prevalent lineage of STEC O157:H7 in England, with a sizeable domestic reservoir. Human infection is associated with the consumption of contaminated fresh produce and contact with domestic livestock. The collection of routine, detailed exposure data on patients who are infected, integrated with high-resolution microbiological typing, enables powerful reframing of our understanding of foodborne disease risk within a One Health context. FUNDING: National Institute for Health and Care Research Health and UK Health Security Agency.

A common framework for using and reporting consumer purchase data (CPD) in foodborne outbreak investigations in Europe.

Consumer purchase data (CPD) can be a powerful tool in the investigation of foodborne outbreaks through analyses of electronic records of food that individuals buy. The objective of this study was to develop a common framework for use of CPD in foodborne outbreak investigations using the expertise of European public health professionals from 11 European countries. We also aimed to describe barriers and limitations preventing CPD utilization. CPD are mainly gathered from supermarket loyalty programmes, smaller consortia, and independent supermarkets. Privacy legislation governing CPD was perceived as the most crucial barrier for CPD usage, but still resolvable. The main practical challenges were obtaining consumer consent for CPD usage, the associated workload, data access, format, and analysis. Harmonising methods and reporting across countries, standardised consent forms and electronic consent methods were identified as solutions. This guideline was developed to support outbreak investigators in overcoming barriers in using CPD, thereby increasing public health professionals' application and value of this powerful investigation tool. In addition, we hope this framework will lead to more public health institutions, in collaboration with food safety authorities, making use of CPD in outbreak investigations in the future.

Agricultural, socioeconomic and environmental variables as risks for human verotoxigenic Escherichia coli (VTEC) infection in Finland.

BACKGROUND: Verotoxigenic E. coli (VTEC) is the cause of severe gastrointestinal infection especially among infants. Between 10 and 20 cases are reported annually to the National Infectious Disease Register (NIDR) in Finland. The aim of this study was to identify explanatory variables for VTEC infections reported to the NIDR in Finland between 1997 and 2006. We applied a hurdle model, applicable for a dataset with an excess of zeros. METHODS: We enrolled 131 domestically acquired primary cases of VTEC between 1997 and 2006 from routine surveillance data. The isolated strains were characterized by virulence type, serogroup, phage type and pulsed-field gel electrophoresis. By applying a two-part Bayesian hurdle model to infectious disease surveillance data, we were able to create a model in which the covariates were associated with the probability for occurrence of the cases in the logistic regression part and the magnitude of covariate changes in the Poisson regression part if cases do occur. The model also included spatial correlations between neighbouring municipalities. RESULTS: The average annual incidence rate was 4.8 cases per million inhabitants based on the cases as reported to the NIDR. Of the 131 cases, 74 VTEC O157 and 58 non-O157 strains were isolated (one person had dual infections). The number of bulls per human population and the proportion of the population with a higher education were associated with an increased occurrence and incidence of human VTEC infections in 70 (17%) of 416 of Finnish municipalities. In addition, the proportion of fresh water per area, the proportion of cultivated land per area and the proportion of low income households with children were associated with increased incidence of VTEC infections. CONCLUSIONS: With hurdle models we were able to distinguish between risk factors for the occurrence of the disease and the incidence of the disease for data characterised by an excess of zeros. The density of bulls and the proportion of the population with higher education were significant both for occurrence and incidence, while the proportion of fresh water, cultivated land, and the proportion of low income households with children were significant for the incidence of the disease.

Assessment of Food and Waterborne Viral Outbreaks by Using Field Epidemiologic, Modern Laboratory and Statistical Methods-Lessons Learnt from Seven Major Norovirus Outbreaks in Finland.

Seven major food- and waterborne norovirus outbreaks in Western Finland during 2014-2018 were re-analysed. The aim was to assess the effectiveness of outbreak investigation tools and evaluate the Kaplan criteria. We summarised epidemiological and microbiological findings from seven outbreaks. To evaluate the Kaplan criteria, a one-stage meta-analysis of data from seven cohort studies was performed. The case was defined as a person attending an implicated function with diarrhoea, vomiting or two other symptoms. Altogether, 22% (386/1794) of persons met the case definition. Overall adjusted, 73% of norovirus patients were vomiting, the mean incubation period was 44 h (4 h to 4 days) and the median duration of illness was 46 h. As vomiting was a more common symptom in children (96%, 143/149) and diarrhoea among the elderly (92%, 24/26), symptom and age presentation should drive hypothesis formulation. The Kaplan criteria were useful in initial outbreak assessments prior to faecal results. Rapid food control inspections enabled evidence-based, public-health-driven risk assessments. This led to probability-based vehicle identification and aided in resolving the outbreak event mechanism rather than implementing potentially ineffective, large-scale public health actions such as the withdrawal of extensive food lots. Asymptomatic food handlers should be ideally withdrawn from high-risk work for five days instead of the current two days. Food and environmental samples often remain negative with norovirus, highlighting the importance of research collaborations. Electronic questionnaire and open-source novel statistical programmes provided time and resource savings. The public health approach proved useful within the environmental health area with shoe leather field epidemiology, combined with statistical analysis and mathematical reasoning.

First respiratory transmitted food borne outbreak?

The world is faced with a remarkable coronavirus outbreak with epicentre in Wuhan, China. Altogether 40554 cases have been confirmed globally with novel coronavirus (SARS-CoV-2) until February 10, 2020. Rigorous surveillance in other countries is required to prevent further global expansion of the outbreak, but resolving the exact mechanism of the initial transmission events is crucial. Most initial cases had visited Huanan South Seafood Market in Wuhan selling also various exotic live animals. Based on the limited initial human-to-human transmission and timely clustering of cases in Huanan market among elderly men, coupled with knowledge that coronaviruses are derived from animals and relationship of SARS-CoV-2 to bat coronavirus, zoonotic transmission in the first instance is probable. To target the actions, similar epidemiological actions to human cases are needed with animal or food exposures. According to current information, an exceptionally wide contamination of seafood market might explain the initiation of the SARS-CoV-2 outbreak. Seafood tanks, air contamination by live animals or rodents are possibilities, but sold animals normally come from various sources. The mode of transmission may become clearer in future: usually in outbreak investigations, hindsight is easy, but for now information about the initial source of this outbreak is limited.

Rigorous surveillance is necessary for high confidence in end-of-outbreak declarations for Ebola and other infectious diseases.

The World Health Organization considers an Ebola outbreak to have ended once 42 days have passed since the last possible exposure to a confirmed case. Benefits of a quick end-of-outbreak declaration, such as reductions in trade/travel restrictions, must be balanced against the chance of flare-ups from undetected residual cases. We show how epidemiological modelling can be used to estimate the surveillance level required for decision-makers to be confident that an outbreak is over. Results from a simple model characterizing an Ebola outbreak suggest that a surveillance sensitivity (i.e. case reporting percentage) of 79% is necessary for 95% confidence that an outbreak is over after 42 days without symptomatic cases. With weaker surveillance, unrecognized transmission may still occur: if the surveillance sensitivity is only 40%, then 62 days must be waited for 95% certainty. By quantifying the certainty in end-of-outbreak declarations, public health decision-makers can plan and communicate more effectively. This article is part of the theme issue 'Modelling infectious disease outbreaks in humans, animals and plants: epidemic forecasting and control'. This issue is linked with the earlier theme issue 'Modelling infectious disease outbreaks in humans, animals and plants: approaches and important themes'.

Shopping Detail Information and Home Freezer Sampling Confirmed the Role of Commercial, Modified-Atmosphere Packaged Meatballs as a Vehicle for Listeriosis in Finland.

In November 2016, an elderly patient was diagnosed with Listeria monocytogenes bacteremia in Finland. Grocery store loyalty card records and microbiological investigation of foods found in the home fridge and freezer of the patient revealed commercial, modified-atmosphere packaged meatballs as the source of the infection. Investigation of the meatball production plant revealed that the floor drain samples were contaminated with the same L. monocytogenes strain as those isolated from the patient and meatballs. Ready-to-eat meatballs were likely contaminated after heat treatment from the production environment before packaging. Long-term cold storage, modified-atmosphere conditions, and the absence of competing bacteria presumably enhanced the growth of L. monocytogenes. We recommend that collection of shopping details and home fridge and freezer sampling should be part of surveillance of all cases of L. monocytogenes infections to complement information obtained from in-depth interviews.

Rapid risk assessment during the early weeks of the 2015-2016 influenza season in Ukraine.

BACKGROUND: Several eastern European countries reported a severe influenza season to the World Health Organization (WHO) during late 2015. A country-specific rapid risk assessment for Ukraine was conducted to assess the season's severity and inform public health action. METHODS: The exposure and hazard were assessed using acute respiratory infection (ARI), severe acute respiratory infection (SARI), laboratory surveillance, virological and vaccine data from weeks 40/2015 to 7/2016 with comparison to 4 previous seasons to describe the influenza season start (5-week consecutive increase in ARI or SARI), predominant virus types, geographical spread and affected age groups. RESULTS: The exposure was characterised by an earlier and steeper increase in SARI (week 1/2016) and ARI (week 2/2016) compared to the previous 4 seasons. Transmission was across Ukraine with an increase in ARI and SARI cases aged 30-64 years compared to 2014/15. Laboratory-confirmed deaths increased from 11 in 2014/2015 to 342 in 2015/2016; the majority were 30-64 years old and unvaccinated; and 63.5% had underlying conditions. Total population vaccination coverage was 0.3%. The hazard assessment found influenza virus A(H1N1)pdm09 accounted for >95% of viruses detected. Ukrainian virus strains (n = 62) were antigenically similar to vaccine strains and susceptible to neuraminidase inhibitors. CONCLUSIONS: The first weeks of the 2015/16 influenza season were more severe than previous seasons, with an earlier and steeper increase in severe cases and deaths, particularly in younger adults. Influenza A(H1N1)pdm09 was the predominant strain and was closely related to the seasonal vaccine strain with no evidence of resistance to antiviral drugs.

An outbreak investigation of paediatric severe acute respiratory infections requiring admission to intensive care units - Fiji, May 2016.

INTRODUCTION: Influenza-associated severe acute respiratory infections (SARI) are a major contributor to global morbidity and mortality. In response to a cluster of SARI cases and deaths in pregnant women, with two deceased cases testing positive for influenza A(H1N1)pdm09, an investigation was initiated to determine whether there was an increase of paediatric SARI cases admitted to divisional hospital intensive care units in Fiji in may 2016 compared to May 2013-2015. METHODS: Retrospective case finding was conducted at the paediatric intensive care units (PICUs) in Fiji's three divisional hospitals. Data were collected from 1 January 2013 to 26 May 2016. Cases were identified using a list of clinical diagnoses compatible with SARI. RESULTS: A total of 632 cases of paediatric SARI with complete details were identified. The median age of cases was 6 months (Interquartile range: 2-14 months). Children aged less than 5 years had a higher rate of paediatric SARI requiring admission to a divisional hospital PICU in May 2016 compared to May 2013-2015 (Incidence rate ratio: 1.7 [95% CI: 1.1-2.6]). This increase was not observed in children aged 5-14 years. The case-fatality ratio was not significantly different in 2016 compared to previous years. CONCLUSION: The investigation enabled targeted public health response measures, including enhanced SARI surveillance at divisional hospitals and an emergency influenza vaccination campaign in the Northern Division.

An Outbreak of Norovirus Infections Among Lunch Customers at a Restaurant, Tampere, Finland, 2015.

On January 29, 2015, the city of Tampere environmental health officers were informed of a possible foodborne outbreak among customers who had eaten lunch in restaurant X. Employees of electric companies A and B had a sudden onset of gastrointestinal symptoms. We conducted a retrospective cohort study to identify the vehicle, source, and causative agent of the outbreak. A case was defined as an employee of companies A or B with diarrhea and/or vomiting who ate lunch at Restaurant X on January 26, 2015. All employees of the companies attending the implicated lunch were invited to participate in the cohort study. Environmental investigation was conducted. Twenty-one responders were included in statistical analysis, of which 11 met with the case definition. Of the 15 food items consumed by participants, four food items were associated with gastroenteritis. Of four kitchen staff, three tested positive for norovirus GIP7, the strain was found earlier in the community. No patient samples were obtained. Level of hygiene in the kitchen was inadequate. Infected kitchen staff probably transmitted norovirus by inadequate hygiene practices. No new cases associated with Restaurant X were reported after the hygiene practices were improved.

Bacterial ghosts as carrier and targeting systems for mucosal antigen delivery.

The application of new strategies to develop effective vaccines is essential in modern medicine. The bacterial ghost system is a novel vaccine delivery system endowed with intrinsic adjuvant properties. Bacterial ghosts are nonliving gram-negative bacterial cell envelopes devoid of cytoplasmic contents while maintaining their cellular morphology and native surface antigenic structures including bioadhesive properties. They are produced by PhiX174 protein E-mediated lysis of gram-negative bacteria. The intrinsic adjuvant properties of bacterial ghost preparations enhance immune responses against envelope-bound antigens, including T-cell activation and mucosal immunity. Since native and foreign antigens can be expressed in the envelope complex of ghosts before E-mediated lysis, multiple antigens of various origin can be presented to the immune system simultaneously. In addition, the extended bacterial ghost system represents a platform technology for specific targeting of DNA-encoded antigens to primary antigen-presenting cells. The potency, safety and relatively low production cost of bacterial ghosts offer a significant technical advantage, especially when used as combination vaccines.

Construction of recombinant S-layer proteins (rSbsA) and their expression in bacterial ghosts--a delivery system for the nontypeable Haemophilus influenzae antigen Omp26.

This study has investigated the feasibility of a combination of recombinant surface layer (S-layer) proteins and empty bacterial cell envelopes (ghosts) to deliver candidate antigens for a vaccine against nontypeable Haemophilus influenzae (NTHi) infections. The S-layer gene sbsA from Bacillus stearothermophilus PV72 was used for the construction of fusion proteins. Fusion of maltose binding protein (MBP) to the N-terminus of SbsA allowed expression of the S-layer in the periplasm of Escherichia coli. The outer membrane protein (Omp) 26 of NTHi was inserted into the N-terminal and C-terminal regions of SbsA. The presence of the fused antigen Omp26 was demonstrated by Western blot experiments using anti-Omp26 antisera. Electron microscopy showed that the recombinant SbsA maintained the ability to self-assemble into sheet-like and cylindrical structures. Recombinant E. coli cell envelopes (ghosts) were produced by the expression of SbsA/Omp26 fusion proteins prior to gene E-mediated lysis. Intraperitoneal immunization with these recombinant bacterial ghosts induced an Omp26-specific antibody response in BALB/c mice. These results demonstrate that the NTHi antigen, Omp26, was expressed in the S-layer self-assembly product and this construct was immunogenic for Omp26 when administered to mice in bacterial cell envelopes.

Bacterial ghosts as vaccine candidates for veterinary applications.

The application of new strategies to develop effective vaccines is essential in modern veterinary medicine. The bacterial ghost system is a novel vaccine delivery system endowed with intrinsic adjuvant properties. Bacterial ghosts are nonliving Gram-negative bacterial cell envelopes devoid of cytoplasmic contents while maintaining their cellular morphology and native surface antigenic structures including bioadhesive properties. They are produced by PhiX174 protein E-mediated lysis of Gram-negative bacteria. The intrinsic adjuvant properties of bacterial ghost preparations enhance immune responses against envelope bound antigens, including T-cell activation and mucosal immunity. Since native and foreign antigens can be expressed in the envelope complex of ghosts before E-mediated lysis, multiple antigens of various origins can be presented to the immune system simultaneously. The advantages of bacterial ghosts include the simplicity of the production method, safety, independence from the cold chain, and versatility as a combination vaccine.

Sealed bacterial ghosts--novel targeting vehicles for advanced drug delivery of water-soluble substances.

The purpose of the present study was to develop a drug delivery model for water soluble drug substances using the bacterial ghost platform technology. Bacterial ghosts are non-denatured bacterial cell envelopes that are produced by the plasmid encoded gene E mediated lysis. We present a novel method to fill and seal bacterial ghosts for the application as a drug delivery system for fluid, non-anchored substances. E. coli ghosts were filled with the reporter substance calcein and sealed by fusion with membrane vesicles. By flow cytometry and fluorescence microscopy it was shown that bacterial ghosts can be filled with calcein, and that the bacterial ghosts can be sealed by restoring the membranes integrity. The adherence and uptake studies showed that almost all murine macrophages and a lower proportion of human colorectal adenocarcinoma cells took up fluorescence labeled bacterial ghosts. Moreover, these cells also took up effectively sealed E. coli ghosts filled with calcein, which then was released within the cells. Therefore, we propose bacterial ghosts as alternative drug delivery and release vehicles for advanced cell targeting.

Interaction between probiotic lactic acid bacteria and canine enteric pathogens: a risk factor for intestinal Enterococcus faecium colonization?

Selected probiotic lactic acid bacteria (LAB) have been shown to elicit positive health effects particularly in humans. Competitive exclusion of pathogens is one of the most important beneficial health claims of probiotic bacteria. The effect of probiotic LAB on competitive exclusion of pathogens has been demonstrated in humans, chicken and pigs. In this study we evaluated the ability of certain LAB strains (Lactobacillus rhamnosus GG, Bifidobacterium lactis Bb12, Lactobacillus pentosus UK1A, L. pentosus SK2A, Enterococcus faecium M74 and E. faecium SF273) to inhibit the adhesion of selected canine and zoonotic pathogens (Staphylococcus intermedius, Salmonella Typhimurium ATCC 14028, Clostridium perfringens and Campylobacter jejuni) to immobilised mucus isolated from canine jejunal chyme in vitro. Adhesion of C. perfringens was reduced significantly by all tested LAB strains, between 53.7 and 79.1% of the control without LAB, the LAB of canine origin yielding the best reduction. The adhesion of S. Typhimurium and S. intermedius were not significantly altered by any of the LAB included in the study. Both enterococci tested significantly enhanced the adhesion of C. jejuni, to 134.6 and 205.5% of the control without LAB. E. faecium may thus favor the adhesion and colonization of C. jejuni in the dog's intestine, making it a potential carrier and possibly a source for human infection. Enhanced C. jejuni adhesion is a new potential risk factor of enterococci. Our results further emphasize the importance of safety guidelines to be established for the probiotics intended for animal use.