Listeria goaensis sp. nov Doijad, Swapnil P; Poharkar, Krupali V; Kale, Satyajit B ...
International journal of systematic and evolutionary microbiology
68, Številka:
10
Journal Article
Recenzirano
Odprti dostop
Two Listeria-like isolates obtained from mangrove swamps in Goa, India were characterized using polyphasic combinations of phenotypic, chemotaxonomic and whole-genome sequence (WGS)-based approaches. ...The isolates presented as short, non-spore-forming, Gram-positive rods, that were non-motile, oxidase-negative, catalase-positive and exhibited α-haemolysis on 5 % sheep- and horse-blood agar plates. The 16S rRNA gene sequences exhibited 93.7-99.7 % nucleotide identity to other Listeria species and had less than 92 % nucleotide identity to species of closely related genera, indicating that the isolates are de facto members of the genus Listeria. Their overall fatty acid composition resembled that of other Listeria species, with quantitative differences in iso C15 : 0, anteiso C15 : 0, iso C16 : 0, C16 : 0, iso C17 : 0 and anteiso C17 : 0 fatty acid profiles. Phylogeny based on 406 core coding DNA sequences grouped these two isolates in a monophyletic clade within the genus Listeria. WGS-based average nucleotide identity and in silico DNA-DNA hybridization values were lower than the recommended cut-off values of 95 and 70 %, respectively, to the other Listeria species, indicating that they are founding members of a novel Listeria species. We suggest the name Listeriagoaensis sp. nov. be created and the type strain is ILCC801
(=KCTC 33909;=DSM 29886;=MCC 3285).
A novel Com1 synthetic peptide-based latex agglutination test (LAT) was developed and evaluated against commercial ELISA kit for sero-screening of coxiellosis in cattle. The developed test is ...economical, has field applicability and can serve as an important rapid tool for sero-screening of coxiellosis in cattle.
We developed the com1 gene based loop-mediated isothermal amplification (LAMP) assay for the detection of Coxiella burnetii and validated it by screening DNA isolated from serum samples collected ...from animals and humans. The detection of Coxiella by LAMP assay was comparable with the com1 based-PCR.
•We developed the com1 gene based loop-mediated isothermal amplification (LAMP) assay for the detection of Coxiella burnetii.•The assay was validated by screening DNA from serum samples of animals and humans.•The LAMP assay was able to detect Coxiella at efficacy comparable to the com1 based-PCR.
Chlamydia psittaci is a zoonotic pathogen mainly transmitted by psittacine birds and poultry. The low shedding rate of the pathogen in the apparently healthy birds and human clinical cases may result ...in false-negative results. In the present study, a droplet digital PCR (ddPCR) assay was developed and compared with optimized quantitative PCR (qPCR) for the detection of C. psittaci from the clinical samples. The ddPCR assay was found to be comparatively more sensitive than the qPCR, wherein the limit of detection (LOD) of ddPCR was upto 2.4 copies of the DNA template, whereas, the qPCR could detect upto 38 copies of the DNA template in the reaction mixture. Overall, the developed ddPCR assay was found to be robust, specific, and could reliably quantify up to 17.8 copies of the DNA template. Finally, the applicability of the developed ddPCR assay was tested by screening the field samples (n = 124), comprising lung tissues from dead poultry and feral birds; pooled faecal samples from the free-living birds, commercial and backyard poultry farms; pharyngeal and cloacal swabs collected from the duck farms. Of these, a total of seven samples were found to be positive by the ddPCR, whereas, three samples could be detected as positive using the qPCR. The developed ddPCR could serve as a reliable screening tool, particularly in those clinical samples wherein the shedding of C. psittaci is substantially very low.
•The study describes development of the ddPCR for the detection of Chlamydia psittaci.•The ddPCR was highly sensitive, and LOD, LOQ were 2.4, 17.8 copies of DNA, respectively•The ddPCR could be a screening tool for clinical samples with low shedding of C. psitaci
ABSTRACT
High throughput in vivo laboratory models is need for screening and identification of effective therapeutic agents to overcome microbial drug-resistance. This study was undertaken to ...evaluate in vivo antimicrobial efficacy of short-chain antimicrobial peptide- Cecropin A (1–7)-Melittin (CAMA) against three multi-drug resistant enteroaggregative Escherichia coli (MDR-EAEC) field isolates in a Galleria mellonella larval model. The minimum inhibitory concentration (MIC; 2.0 mg/L) and minimum bactericidal concentration (MBC; 4.0 mg/L) of CAMA were determined by microdilution assay. CAMA was found to be stable at high temperatures, physiological concentration of cationic salts and proteases; safe with sheep erythrocytes, secondary cell lines and commensal lactobacilli at lower MICs; and exhibited membrane permeabilization. In vitro time-kill assay revealed concentration- and time-dependent clearance of MDR-EAEC in CAMA-treated groups at 30 min. CAMA- treated G. mellonella larvae exhibited an increased survival rate, reduced MDR-EAEC counts, immunomodulatory effect and proved non-toxic which concurred with histopathological findings. CAMA exhibited either an equal or better efficacy than the tested antibiotic control, meropenem. This study highlights the possibility of G. mellonella larvae as an excellent in vivo model for investigating the host-pathogen interaction, including the efficacy of antimicrobials against MDR-EAEC strains.
This study was undertaken to evaluate in vivo antimicrobial efficacy of short-chain antimicrobial hybrid peptide- Cecropin A (1-7)-Melittin against three multi-drug resistant enteroaggregative E. coli field isolates in a G. mellonella larval model.
Numerous studies have demonstrated that targeting Ag to Fc receptors (FcR) on APCs can enhance humoral and cellular immunity. However, studies are lacking that examine both the use of FcR-targeting ...in generating immune protection against infectious agents and the use of FcRs in the induction of mucosal immunity. Francisella tularensis is a category A intracellular mucosal pathogen. Thus, intense efforts are underway to develop a vaccine against this organism. We hypothesized that protection against mucosal infection with F. tularensis would be significantly enhanced by targeting inactivated F. tularensis live vaccine strain (iFt) to FcRs at mucosal sites, via intranasal immunization with mAb-iFt complexes. These studies demonstrate for the first time that: 1) FcR-targeted immunogen enhances immunogen-specific IgA production and protection against subsequent infection in an IgA-dependent manner, 2) FcgammaR and neonatal FcR are crucial to this protection, and 3) inactivated F. tularensis, when targeted to FcRs, enhances protection against the highly virulent SchuS4 strain of F. tularensis, a category A biothreat agent. In summary, these studies show for the first time the use of FcRs as a highly effective vaccination strategy against a highly virulent mucosal intracellular pathogen.
The present investigation of Coxiella burnetii infection in cattle and farm workers on an organized cattle dairy farm, which appears to be the first of its kind in India, was undertaken to assess the ...status of this largely neglected and masked zoonosis.
A total of 665 samples comprising of serum (n=224), milk (n=217) and vaginal swabs (n=224) collected from milch animals (n=224) with a history of reproductive disorders were screened. Besides these, ticks (n=114); animal feed (n=4) and environmental samples (n=13) as well as serum (n=19) of farm workers were also collected. The animal sera and milk samples as well as human sera were tested for antibodies against C. burnetii by commercial ELISA kit, whereas, all the collected samples were subjected to trans-PCR targeting the IS1111 gene of C. burnetii.
A high positivity for coxiellosis was detected in sera (29.91%) and milk (26.73%) samples of dairy cattle as well as sera from human contacts (84.21%) by ELISA. The trans-PCR detected the pathogen in 12.94% sera, 14.73% vaginal swabs and 5.53% milk samples of cattle, and in one soil sample, however, the sera of the farm workers and tick were tested negative.
The high positivity for coxiellosis among cattle and farm workers highlight the need to undertake extensive epidemiological studies to unravel the trends of C. burnetii infection in India.
Q fever caused by Coxiella burnetii is an important zoonosis and has great public health significance. A total of 905 clinical samples from 387 cattle serum (n = 387); vaginal swabs (n = 387); milk ...(n = 131) and 59 serum samples from humans were collected from gaushala (cattle shelter) and screened for anti-C. burnetii IgG antibodies in the sera using an indirect-ELISA kit. Further, the samples were tested for C. burnetii DNA employing TaqMan real-time and conventional PCR assays targeting the com1 gene. In ELISA, 9.56% and 6.78% of animal and human sera samples were positive for anti-C. burnetii antibodies, respectively. Upon pathogen detection, 3.87% sera, 1.81% vaginal swabs, and 6.87% milk samples from cattle tested positive in TaqMan real-time PCR and 1.55% sera, 0.52% vaginal swabs, and 3.05% milk samples were found positive in conventional PCR. In humans, one serum sample was positive in both the PCR assays. The PCR positive samples (n = 12) were partially sequenced and the phylogenetic tree was constructed using com1 gene sequences (n = 42) from a different host and geographical areas. The study highlights infection of cattle and their human contacts in gaushala and identifies relationships between strains identified in the gaushala and those in other parts of the globe.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, GIS, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Q fever caused by
is an important zoonosis and has great public health significance. A total of 905 clinical samples from 387 cattle serum (
= 387); vaginal swabs (
= 387); milk (
= 131) and 59 ...serum samples from humans were collected from gaushala (cattle shelter) and screened for anti-
IgG antibodies in the sera using an indirect-ELISA kit. Further, the samples were tested for
DNA employing TaqMan real-time and conventional PCR assays targeting the
1 gene. In ELISA, 9.56% and 6.78% of animal and human sera samples were positive for anti-
antibodies, respectively. Upon pathogen detection, 3.87% sera, 1.81% vaginal swabs, and 6.87% milk samples from cattle tested positive in TaqMan real-time PCR and 1.55% sera, 0.52% vaginal swabs, and 3.05% milk samples were found positive in conventional PCR. In humans, one serum sample was positive in both the PCR assays. The PCR positive samples (
= 12) were partially sequenced and the phylogenetic tree was constructed using
gene sequences (
= 42) from a different host and geographical areas. The study highlights infection of cattle and their human contacts in gaushala and identifies relationships between strains identified in the gaushala and those in other parts of the globe.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, GIS, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Listeria
contamination in foods of animal origin is one of the most concerning food safety issues. A duplex, SYBR green-based, real-time PCR assay was developed with high-resolution melting ...analysis-based differentiation of the genus
Listeria
and
Listeria monocytogenes
. The primers were designed and tested against other related foodborne pathogens. The assay was optimized for standard parameters in a non-orthogonal fashion and validated following international standards. The LOD
abs
and LOQ of the assay were calculated to be 0.78 and 1.56 ng of the target DNA. The LOD
rel
of the assay was found to be 1%
Listeria
DNA in background DNA. The assay was evaluated for applicability in artificially spiked samples, providing a 120 CFU/ml detection. The assay was validated with proficiency test samples and also with samples collected for surveillance analysis. This well-established and validated assay can be utilized as a qualitative and quantitative tool for addressing the
Listeria
contamination in the food safety contexts.
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