Article Subject: Molecular Microbiology DOI: Background and Aims: Listeria monocytogenes, a gram positive, facultative, intracellular bacterium is the causative agent of listeriosis that is transmitted to human through raw and ready-to-eat foods. The aim of the present study was to determine dominant serovars of L. monocytogenes isolated from spontaneous abortion using phenotypic and genotypic methods. Materials and Methods: In present study, 258 clinical specimens including placental secretions, vaginal swabs and blood samples from 123 patients with abortion were selected in sterile condition then bacteriological, serological and molecular tests were conducted; dominant serotypes were identified by Multiplex PCR. Results: Out of 28 (%18.8) isolates of L. monocytogenes 21 (%17.7), 5 (%5.7) and 2 (%3.37) were isolated from placental secretions, vaginal swabs and blood respectively. Maximum and minimum isolated of bacteria related to placental secretions and vaginal swabs with 21 and 2 isolates respectively, of which 14 (%50) 1/2a, 10 (%35.7) 4b and 4 (%14.6) 2c serovars were reported for the first time. All of serovars played a key role in the spontaneous abortion as dominant and common serotypes in Iran. All of the isolates 28 (%22.76) showed hlyA gene and 24 isolates (%19.57) were positive for iap gene and compaired with control group there was significant different between the two groups (P<0.0002). Conclusion: The present study showed the isolation dominant and common serotypes of L. monocytogenes from spontaneous abortion and demonstrated that the presence of hlyA and iap were effective genes in increasing aggressive and pathogenicity. Serotypes that lacked the iap gene have less pathogenicity and influenced the pathogenesis in mice. It was also concluded that in the absence of access to molecular tests, performing PI-PLC, Congored and in vivo pathogenicity can be effective in detecting pathogenic serotypes from non-pathogenic L. monocytogenes.
Background:
Lately, the employment of nano-carriers has been known as an optimistic means of drug and
vaccine delivery.
Objective:
Nano vaccines are a novel tier of vaccines that can develop humoral and cellular immune responses and can be
introduced as a practical and secure nano vaccine candidate the prevention of diseases. The purpose of this study was to
accomplish and use biodegradable nano-carriers for the synthesis of pentavalent vaccine and immunogenicity evaluation in
the animal models.
The PLGA nanoparticle was prepared and modified with chitosan nanoparticle. Nano-carrier PLGA-chitosan was loaded by
the DTP-HepB-Hib antigens and confirmed by DLS, SEM, TEM and FT-IR then the in vitro loading and release were
evaluated. The toxicity was assessed by the MTT method in the Hec293 cells. The antigenicity evaluation and
histopathological study were conducted by injection of new nano pentavalent vaccines in the BALB/c mice and the immune
response was measured in the serum samples through an indirect ELISA method.
Results:
Conclusions drawn from the current study exhibited the plausible ability of nano-carrier to deliver vaccine. A
notable increase was shown in total IgG and IgM antibodies examined on mice vaccinated with new nano vaccines. The
histopathological study in the treated mice showed no toxicity in vital organs of mice.
Conclusion:
The engineered vaccine delivery system showed the ability to induce robust immune responses and also the
suitability features of the PLGA-chitosan as a promising carrier to improve vaccine delivery.
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