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- Fast and sensitive detection of enteropathogenic Yersinia by immunoassays. [JOURNAL ARTICLE]
- J Clin Microbiol 2014 Oct 29.
Yersinia enterocolitica and Yersinia pseudotuberculosis, the two enteropathogenic Yersinia species for humans are worldwide distributed and are causing frequently diarrhea to inhabitants of temperate and cold countries. Yersinia enterocolitica is a major cause of foodborne disease, by consumption of contaminated pork meat further associated substantial economic cost. However, investigating enteropathogenic Yersinia is hardly performed routinely in clinical laboratories because of their specific growth characteristics, which make difficult their isolation from stools samples. Moreover, current isolation procedures are time consuming and expensive, thus leading to underestimated incidence of enteric yersiniosis, inappropriate prescriptions of antibiotic treatments and unnecessary appendectomies. The main objective of the study was to develop fast, sensitive, specific and easy-to-use immunoassays, useful for both human and veterinary diagnosis. Monoclonal antibodies (mAbs) directed against Y. enterocolitica bioserotypes 2/O:9 and 4/O:3 and Y. pseudotuberculosis serotypes I and III were produced. Pairs of mAbs were selected by testing their specificity and affinity toward enteropathogenic Yersinia and other commonly found enterobacteria. Pairs of mAbs were selected to develop highly sensitive enzyme immunoassays (EIA) and lateral flow immunoassays (LFI or dipsticks) convenient for rapid diagnostic purpose. The limit of detection of the EIAs ranged from 3.2 x 10(3) cfu/ml to 8.8 x 10(4) cfu/ml for pathogenic serotypes I and III of Y. pseudotuberculosis and pathogenic bioserotypes 2/O:9 and 4/O:3 of Y. enterocolitica and ranged for the LFIs from 10(5) cfu/ml to 10(6) cfu/ml. A similar limit of detection was observed for artificially contaminated human feces.
- Complete genome sequence of bacteriophage vB_YenP_AP5 which infects Yersinia enterocolitica of serotype O:3. [JOURNAL ARTICLE]
- Virol J 2014 Oct 28; 11(1):188.
Bacteriophage vB_YenP_AP5 is a lytic bacteriophage capable of infecting Yersinia enterocolitica strains of serotype O:3, an epidemiologically significant serotype within this bacterial species that causes yersiniosis in humans. This work describes the complete genome sequence of this phage.The genome consists of linear double-stranded DNA of 38,646 bp, with direct terminal repeats of 235 bp in length, and a GC content of 50.7%. There are 45 open reading frames which occupy 89.9% of the genome. Most of the proteins encoded by this virus exhibit sequence similarity to Yersinia phage phiYeO3-12 and Salmonella phage phiSG-JL2 proteins.Genomic and morphological analyses place the bacteriophage vB_YenP_AP5 in the T7likevirus genus of the subfamily Autographivirinae within the family Podoviridae.
- Real-time TaqMan PCR for Yersinia enterocolitica detection based on the ail and foxA genes. [JOURNAL ARTICLE]
- J Clin Microbiol 2014 Oct 22.
Yersinia enterocolitica, a cause of emerging enteric infections, is a food-borne pathogen with various enteric and systemic syndromes e.g., diarrhea, enteritis and enterocolitis.…
- Detection of Rickettsia felis, Rickettsia typhi, Bartonella Species and Yersinia pestis in Fleas (Siphonaptera) from Africa. [Journal Article]
- PLoS Negl Trop Dis 2014 Oct; 8(10):e3152.
Little is known about the presence/absence and prevalence of Rickettsia spp, Bartonella spp. and Yersinia pestis in domestic and urban flea populations in tropical and subtropical African countries.Fleas collected in Benin, the United Republic of Tanzania and the Democratic Republic of the Congo were investigated for the presence and identity of Rickettsia spp., Bartonella spp. and Yersinia pestis using two qPCR systems or qPCR and standard PCR. In Xenopsylla cheopis fleas collected from Cotonou (Benin), Rickettsia typhi was detected in 1% (2/199), and an uncultured Bartonella sp. was detected in 34.7% (69/199). In the Lushoto district (United Republic of Tanzania), R. typhi DNA was detected in 10% (2/20) of Xenopsylla brasiliensis, and Rickettsia felis was detected in 65% (13/20) of Ctenocephalides felis strongylus, 71.4% (5/7) of Ctenocephalides canis and 25% (5/20) of Ctenophthalmus calceatus calceatus. In the Democratic Republic of the Congo, R. felis was detected in 56.5% (13/23) of Ct. f. felis from Kinshasa, in 26.3% (10/38) of Ct. f. felis and 9% (1/11) of Leptopsylla aethiopica aethiopica from Ituri district and in 19.2% (5/26) of Ct. f. strongylus and 4.7% (1/21) of Echidnophaga gallinacea. Bartonella sp. was also detected in 36.3% (4/11) of L. a. aethiopica. Finally, in Ituri, Y. pestis DNA was detected in 3.8% (1/26) of Ct. f. strongylus and 10% (3/30) of Pulex irritans from the villages of Wanyale and Zaa.Most flea-borne infections are neglected diseases which should be monitored systematically in domestic rural and urban human populations to assess their epidemiological and clinical relevance. Finally, the presence of Y. pestis DNA in fleas captured in households was unexpected and raises a series of questions regarding the role of free fleas in the transmission of plague in rural Africa, especially in remote areas where the flea density in houses is high.
- A Non-Stationary Relationship between Global Climate Phenomena and Human Plague Incidence in Madagascar. [Journal Article]
- PLoS Negl Trop Dis 2014 Oct; 8(10):e3155.
Plague, a zoonosis caused by Yersinia pestis, is found in Asia and the Americas, but predominantly in Africa, with the island of Madagascar reporting almost one third of human cases worldwide. Plague's occurrence is affected by local climate factors which in turn are influenced by large-scale climate phenomena such as the El Niño Southern Oscillation (ENSO). The effects of ENSO on regional climate are often enhanced or reduced by a second large-scale climate phenomenon, the Indian Ocean Dipole (IOD). It is known that ENSO and the IOD interact as drivers of disease. Yet the impacts of these phenomena in driving plague dynamics via their effect on regional climate, and specifically contributing to the foci of transmission on Madagascar, are unknown. Here we present the first analysis of the effects of ENSO and IOD on plague in Madagascar.We use a forty-eight year monthly time-series of reported human plague cases from 1960 to 2008. Using wavelet analysis, we show that over the last fifty years there have been complex non-stationary associations between ENSO/IOD and the dynamics of plague in Madagascar. We demonstrate that ENSO and IOD influence temperature in Madagascar and that temperature and plague cycles are associated. The effects on plague appear to be mediated more by temperature, but precipitation also undoubtedly influences plague in Madagascar. Our results confirm a relationship between plague anomalies and an increase in the intensity of ENSO events and precipitation.This work widens the understanding of how climate factors acting over different temporal scales can combine to drive local disease dynamics. Given the association of increasing ENSO strength and plague anomalies in Madagascar it may in future be possible to forecast plague outbreaks in Madagascar. The study gives insight into the complex and changing relationship between climate factors and plague in Madagascar.
- Caenorhabditis elegans Bacterial Pathogen Resistant bus-4 Mutants Produce Altered Mucins. [Journal Article]
- PLoS One 2014; 9(10):e107250.
Caenorabditis elegans bus-4 glycosyltransferase mutants are resistant to infection by Microbacterium nematophilum, Yersinia pestis and Yersinia pseudotuberculosis and have altered susceptibility to two Leucobacter species Verde1 and Verde2. Our objective in this study was to define the glycosylation changes leading to this phenotype to better understand how these changes lead to pathogen resistance. We performed MALDI-TOF MS, tandem MS and GC/MS experiments to reveal fine structural detail for the bus-4 N- and O-glycan pools. We observed dramatic changes in O-glycans and moderate ones in N-glycan pools compared to the parent strain. Ce core-I glycans, the nematode's mucin glycan equivalent, were doubled in abundance, halved in charge and bore shifts in terminal substitutions. The fucosyl O-glycans, Ce core-II and neutral fucosyl forms, were also increased in abundance as were fucosyl N-glycans. Quantitative expression analysis revealed that two mucins, let-653 and osm-8, were upregulated nearly 40 fold and also revealed was a dramatic increase in GDP-Man 4,6 dehydratease expression. We performed detailed lectin binding studies that showed changes in glycoconjugates in the surface coat, cuticle surface and intestine. The combined changes in cell surface glycoconjugate distribution, increased abundance and altered properties of mucin provide an environment where likely the above pathogens are not exposed to normal glycoconjugate dependent cues leading to barriers to these bacterial infections.
- Effect of nanovaccine chemistry on humoral immune response kinetics and maturation. [Journal Article]
- Nanoscale 2014 Oct 24; 6(22):13770-8.
Acute respiratory infections represent a significant portion of global morbidity and mortality annually. There is a critical need for efficacious vaccines against respiratory pathogens. To vaccinate against respiratory disease, pulmonary delivery is an attractive route because it mimics the route of natural infection and can confer both mucosal and systemic immunity. We have previously demonstrated that a single dose, intranasal vaccine based on polyanhydride nanoparticles elicited a protective immune response against Yersinia pestis for at least 40 weeks after immunization with F1-V. Herein, we investigate the effect of nanoparticle chemistry and its attributes on the kinetics and maturation of the antigen-specific serum antibody response. We demonstrate that manipulation of polyanhydride nanoparticle chemistry facilitated differential kinetics of development of antibody titers, avidity, and epitope specificity. The results provide new insights into the underlying role(s) of nanoparticle chemistry in providing long-lived humoral immunity and aid in the rational design of nanovaccine formulations to induce long-lasting and mature antibody responses.
- [Development and testing of an enzyme immunoassay-based monoclonal test system for the detection of the Yersinia pestis V antigen]. [English Abstract, Journal Article]
- Prikl Biokhim Mikrobiol 2014 Mar-Apr; 50(2):211-8.
An enzyme immunoassay-based test system for Y. pestis V antigen detection was developed. The specificity and sensitivity of this system met the requirements for medical immunobiological preparations for the identification of causative agents of highly fatal diseases. The sensitivity of the test system was assessed, and its high specificity was also demonstrated: the test system did not detect bacterial cells of closely related (four Y. pseudotuberculosis strains) and heterologous microorganism strains. The test system developed was able to detect the V antigen at concentrations as low as 2.0 ng/mL in cells of nine experimental Y. pestis cultures. The obtained preparation can be recommended for use in laboratory diagnostics of plaque.
- ` Candidatus Rickettsia asemboensis¿ and Wolbachia spp. in Ctenocephalides felis and Pulex irritans fleas removed from dogs in Ecuador. [JOURNAL ARTICLE]
- Parasit Vectors 2014 Sep 30; 7(1):455.
BackgroundFlea-borne infections are distributed worldwide. Up to date there are no reports about microorganisms associated to fleas in Ecuador.MethodsSeventy-one Pulex irritans and 8 Ctenocephalides felis fleas were removed from dogs in two Ecuadorian areas (Pastaza and Chimborazo Provinces) in December 2012. DNA extracts were tested by polymerase chain reaction (PCR) assays targeting universal 16S rRNA, as well as screened for the presence of Rickettsia spp. (gltA, htrA, ompB, sca4 and ompA genes) and Bartonella spp. (rpoB, gltA and ITS genes).ResultsOur results showed the presence of `Candidatus Rickettsia asemboensis¿ (highly similar to R. felis) in C. felis and Wolbachia spp. endosimbionts in P. irritans collected from animals in Ecuador. No fleas were found to be positive for any Bartonella species or Yersinia pestis.ConclusionsClinicians should be aware of the potential risk of this new Candidatus Rickettsia sp. and keep in mind other flea-borne infections since these flea species frequently bite humans.
- The multifaceted nature of NLRP12. [REVIEW]
- J Leukoc Biol 2014 Sep 23.
NLRs are a class of cytoplasmic PRRs with various functions, ranging from pathogen/damage sensing to the modulation of inflammatory signaling and transcriptional control of MHC and related genes. In addition, some NLRs have been implicated in preimplantation and prenatal development. NLRP12 (also known as RNO, PYPAF7, and Monarch-1), a member of the family containing an N-terminal PYD, a NBD, and a C-terminal LRR region, is one of the first described NLR proteins whose role remains controversial. The interest toward NLRP12 has been boosted by its recent involvement in colon cancer, as well as in the protection against some severe infections, such as that induced by Yersinia pestis, the causative agent of plague. As NLRP12 is mainly expressed by the immune cells, and its expression is down-regulated in response to pathogen products and inflammatory cytokines, it has been predicted to play a role as a negative regulator of the inflammatory response. Herein, we present an overview of the NLR family and summarize recent insights on NLRP12 addressing its contribution to inflammatory signaling, host defense, and carcinogenesis.