Regulating Effects of Novel CpG Chitosan-nanoparticles on Immune Responses of Mice to Porcine Paratyphoid Vaccines

Objective To study the regulating effects of a novel CpG oligodeoxynuleotide and the synergistic effect of chitosan-nanoparticles （CNP） with CpG on immune responses of mice, which were used to develop a novel immunoadjuvant to boost immune response to conventional vaccines. Methods A novel CpG ODN containing 11 CpG motifs was synthesized and its bioactivities to stimulate the proliferation of lymphocytes of pig in vitro were detected. Then it was entrapped with CNP prepared in our laboratory by the method of ionic cross linkage, and immunized Kunming mice were co-inoculated with paratyphoid vaccine. The peripheral blood was collected weekly from the tail vein of inoculated mice to detect the contents of IgG, IgA, IgM, and specific antibody against salmonella as well as the levels of interleukin-2 （IL2）, IL-4, and IL-6 by SABC-ELISA assay. The numbers of leucocytes, monocytes, granuloytes, and lymphocytes were calculated separately using the routine method. The experimental mice were orally challenged with virulent salmonella 35 days after inoculation. Results This CpG ODN could remarkably provoke the proliferation of lymphocytes of pig in vitro in contrast with the control （P〈0.05）. Compared with those of the control, immunoglobulins, including IgG, IgA, IgM, and specific antibodies to paratyphoid vaccine, increased significantly in sera from the CpG or CpG-CNP-vaccinated mice （P〈0.05）. IL-2, IL-4, and IL-6 increased remarkably in sera from immunized mice （P〈0.05）. The leucocytes, monocytes, granuloytes, and lymphocytes of the mice immunized with CpG or CpG-CNP were also increased in number （P〈0.05）. After the challenge, these immunity values were elevated in the mice vaccinated with CpG or CpG-CNP. The immunized mice all survived, while the control mice fell ill with evident lesions with diffuse hemorrhage in stomach, small intestine, and peritoneum. Conclusions CpG ODN entrapped with CNP is a promising effective immunoadjuvant for vaccination, which promotes humoral and cellular immune responses, enhances immunity and resistance against salmonella by co-administration with paratyphoid vaccine. Key words：

Some pathogenic characters of paratyphoid Salmonella enterica strains isolated from poultry

Objective: To investigate some pathogenic characters of Salmonella enterica strains isolated from poultry.Methods: Twenty-three genetically distinct Salmonella enterica strains, of different serovars and pulsotype, were examined for virulence traits. Resistance to gastric acid environment was estimated by measuring the percentage of survived bacterial cells after exposure for 2 h to a synthetic gastric juice. Strains were analyzed with PCR for the presence of the following virulence genes: mgtC and rhu M located on SPI-3, sopB and pipB located on SPI-5, Salmonella virulence plasmid(spv)R(spvR), spvB and spvC located on Salmonella plasmid virulence and sodCI, sopE, and gipA located on prophage.Finally, resistance to 21 antibiotics was tested with Kirby–Bauer method.Results: A percentage of 82.60% of strains were resistant to gastric environment after induction and 60.87% of the strains exhibited constitutive resistance too. Nineteen different virulence profiles were detected. The phage related genes sodCI and sopE and the plasmid mediated operon spvR, spvB and spvC(spvRBC) were detected in 82.60%,47.82% and 52.17% of strains, respectively. Typhimurium and Enteritidis strains showed the highest number of virulence genes. Twenty-one different antibiotic resistance profiles were obtained and two isolates(Typhimurium and Enteritidis) resulted sensible to all the tested molecules. The ampicillin, streptomycin, sulfonamide and tetracycline resistance profile was detected in seven isolates(30.43%).Conclusion: Our results show that paratyphoid Salmonella strains with several characters of pathogenicity, that may be cause of severe pathology in animals and humans, are circulating among poultry.

Paratyphoid fever- Emerging problem in South India

Objective:To review the clinical profile and drug susceptibilities of Salmonella paratyphi A in a tertiary care hospital.Methods:Retrospective analyses of 113 patients with paratyphoid fever and 101 culture proven Salmonella paratyphi A infection were included in the study.The study extended over a period of 3 years(2006-2008).Diagnosis of patients were based on clinical features,serology and blood culture.The drug susceptibility testing of the isolates were performed by the disc diffusion method.Clinical presentation,laboratory parameters,susceptibility patterns of isolates,treatment and clinical response were studied.Results:Of the 113 cases,77(68.4%) were males and 36 were females(32.8%),which included 2 pediatric patients.Fever was the most common symptom(100.0%) followed by loose stools(37.2%),headache(35.4%),myalgia(31.9%), pain abdomen(29.2%),dry cough(19.5%) and vomiting(13.3%).All patients were clinically cured. Majority of the isolates(46%) were resistant to cotrimoxazole in 2006,however they became 100% sensitive in 2007 and 2008.whereas the strains became 100% sensitive to ampicillin and chloramphenicol only in 2008.In 2006 the sensitivity of organisms to ciprofloxacin was 89% but in 2007 and 2008 there has been an increasing resistance to ciprofloxacin(46% and 86%) respectively.Surprisingly 3 isolates(8.1%) were resistant to ceftriaxone in 2006,showed 100% sensitivity in 2008.Common drugs used were ceftriaxone in 100 cases(88.4%) and ciprofloxacin in 13 cases(11.6%).One patient had relapse of paratyphoid fever after treatment with ciprofloxacin which responded to ceftriaxone.Conclusions:Paratyphoid fever A is one of the emerging infections and a significant problem in India.An increasing resistance to fluoroquinolones is noted.Continuous monitoring of drug susceptibilities is mandatory in instituting appropriate therapy.

Association between the incidence of typhoid and paratyphoid fever and meteorological variables in Guizhou, China

Background Typhoid/paratyphoid fever （TPF） is endemic in Guizhou.We conducted wavelet analysis and Spearman＇s rank correlation analysis to explore the impact of meteorological variations on TPF infection in Guizhou,in an attempt to assess the risk factors associated with TPF epidemics.Methods We examined the association between TPF incidence in Guizhou and temperature,precipitation and relative humidity using 24 years of data from 1984 to 2007.Periodicities of TPF incidence and the impact of climate factors on the TPF were detected by Spearman＇s rank correlation and wavelet analysis,Results Temperature and precipitation with a 1-month lag were positively correlated with the monthly incidence of TPF.The multiyear incidence pattern of TPF in Guizhou was explicitly periodic.Moreover,the association and driving effect of precipitation on TPF were observed,and the results showed that the incidence of TPF in Guizhou had a closer correlation with precipitation than with temperature.Conclusions Safe water supply is the key issue for TPF control in Guizhou.Moreover,climate variation might impact the enteric infections,which may inform policy assessment for TPF control in Guizhou.