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Experimental Animals Jan 2008To investigate the pathogenicities of P. pneumotropica (Pp) and V-factor dependent Pasteurellaceae (VFDP) in immunodeficient rats, experimental infections of F344-rnu...
To investigate the pathogenicities of P. pneumotropica (Pp) and V-factor dependent Pasteurellaceae (VFDP) in immunodeficient rats, experimental infections of F344-rnu rats were performed using 3 strains (ATCC 35149, CNP 160 and RPZ) of Pp and 4 strains (V6, V7, V8 and V9) of VFDP. Four animals per experimental group were inoculated twice on day 0 and post-inoculation day (PID) 14 with bacterial suspension intranasally. Two animals from each group were sacrificed on PID 60 and 120, and examined. In the animals inoculated with strains of Pp, sneezing was observed in some animals inoculated with strains ATCC 35149 and CNP 160 until PID 31. No clinical signs were observed in other animals. The strains were mainly isolated from the nasal cavity and trachea on PID 60, and the nasal cavity, trachea and lung on PID 120. Inflammation and necrosis of nasal cavity mucosa were observed in all animals inoculated with strains ATCC 35149 and CNP 160 in a histopathologic examination. No histopathological changes were observed in any other animal. In the animals inoculated with strains of VFDP, neither clinical disorder nor histopathological change was observed. The strains were mainly isolated from the trachea on PID 60, and from the trachea and lungs on PID 120. From these results, the pathogenicity of Pp in immunodeficient rats appears to differ by strain, and VFDP appears to be non-pathogenic in immunodeficient rats.
Topics: Animals; Female; Immunologic Deficiency Syndromes; Pasteurella pneumotropica; Pasteurellaceae; Pasteurellaceae Infections; Rats; Rats, Inbred F344; Rats, Mutant Strains; Rodent Diseases
PubMed: 18256519
DOI: 10.1538/expanim.57.57 -
Infection and Immunity Jan 2021-Ribosylhomocysteinase (LuxS) is required for the synthesis of the autoinducer-2 (AI-2) quorum-sensing signaling molecule in many Gram-negative bacteria. The bovine (and... (Comparative Study)
Comparative Study
-Ribosylhomocysteinase (LuxS) is required for the synthesis of the autoinducer-2 (AI-2) quorum-sensing signaling molecule in many Gram-negative bacteria. The bovine (and ovine) opportunistic pathogen contains and forms a biofilm containing an exopolysaccharide (EPS) in the matrix. Since biofilm formation is regulated by quorum sensing in many bacteria, the roles of in virulence and biofilm formation were investigated. Although culture supernatants from were ineffective at inducing bioluminescence in the reporter strain BB170, complemented the biosynthesis of AI-2 in the -deficient strain DH5α. strain 2336 was inactivated by transposon mutagenesis. RNA expression profiles revealed that many genes were significantly differentially expressed in the mutant compared to that in the wild-type, whether the bacteria were grown planktonically or in a biofilm. Furthermore, the mutant had a truncated and asialylated lipooligosaccharide (LOS) and was substantially more serum sensitive than the wild-type. Not surprisingly, the mutant was attenuated in a mouse model for virulence, and some of the altered phenotypes were partially restored after the mutation was complemented with a functional However, no major differences were observed between the wild-type and the mutant in regard to outer membrane protein profiles, biofilm formation, EPS production, or intracellular survival. These results indicate that plays a role in virulence in the context of LOS biosynthesis but not biofilm formation or other phenotypic properties examined.
Topics: Animals; Bacterial Proteins; Biofilms; Carbon-Sulfur Lyases; Cattle; Disease Models, Animal; Genetic Variation; Genotype; Humans; Lipopolysaccharides; Mice; Pasteurellaceae; Pasteurellaceae Infections; Quorum Sensing; Sheep; Virulence
PubMed: 33139386
DOI: 10.1128/IAI.00567-20 -
Comparative Medicine Dec 2020The internal transcribed spacer (ITS) regions of , , , , and and of a related β-hemolytic taxon isolated from laboratory rodents were studied for their feasibility...
The internal transcribed spacer (ITS) regions of , , , , and and of a related β-hemolytic taxon isolated from laboratory rodents were studied for their feasibility to discriminate among these species. The 6 species analyzed showed species-specific ITS patterns that were shared by the type strains and clinical isolates and that allowed their identification. Nevertheless, differentiating between the ITS band patterns of and is visually challenging. In all species tested, sequence analysis of the ITS fragments revealed a larger ITS, which contained the genes for tRNA and tRNA , and a smaller ITS with the tRNA gene. The ITS sequences varied among the 6 species evaluated, displaying identity levels ranging from 62% to 86% for ITS and 68% to 90% for ITS. Overall, ITS amplification proved to be a reliable method to differentiate among these important species of laboratory rodents. Moreover, the ITS sequence variations recorded here might facilitate the design of probes for specific identification of these species. The ability to diagnose these organisms to the species level could increase our understanding of their clinical significance.
Topics: Animals; DNA, Bacterial; Pasteurella pneumotropica; Pasteurellaceae; RNA, Ribosomal, 16S; RNA, Ribosomal, 23S; Rodentia; Sequence Analysis, DNA
PubMed: 33121574
DOI: 10.30802/AALAS-CM-99-990085 -
Identification of a large repetitive RTX immunogen in a highly virulent Rodentibacter heylii strain.Microbes and Infection 2021Rodentibacter (R.) heylii is frequently detected in laboratory rodents. Repeats in toxin (RTX) toxins are considered important virulence factors of this major murine...
Rodentibacter (R.) heylii is frequently detected in laboratory rodents. Repeats in toxin (RTX) toxins are considered important virulence factors of this major murine pathogen. We evaluated the virulence of a R.heylii strain negative for all known RTX toxin genes and Muribacter (M.) muris, a commensal in mice, in experimental infections of C57BL/6 and BALB/c mice. Experimental intranasal infection with 10 CFU of the pnxI-, pnxII- and pnxIII- R. heylii strain resulted in 75% and 100% mortality in C57BL/6 and BALB/c mice, respectively. In early losses, multiple internal organs were infected and purulent bronchopneumonia was the main pathology. Intranasal application of M. muris did not result in mortality or severe weight loss. Immunoproteomics led to the identification of a surface-associated and specific immunogen, which was designated as R. heylii immunogen A (RhiA) and which was exclusively recognised by sera obtained from mice infected with this R. heylii pathotype. RhiA is a 262.6 kDa large protein containing long imperfect tandem repeats and C-terminal RTX consensus sequences. Immunohistochemical analysis confirmed that this R.heylii pathotype expresses RhiA in the lower respiratory tract. In summary, this study describes a specific immunogen in a virulent R. heylii, strain which is an excellent antigen for pathotype-specific serological screenings and which might carry out RTX-related functions.
Topics: Animals; Bacterial Proteins; Bacterial Toxins; Consensus Sequence; Male; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Pasteurellaceae; Pasteurellaceae Infections; Protein Domains; Tandem Repeat Sequences; Virulence; Virulence Factors
PubMed: 33164813
DOI: 10.1016/j.micinf.2020.10.007 -
The Lancet. Microbe Aug 2022
Topics: Humans; Pasteurella; Pasteurella Infections; Pasteurella multocida; Public Health
PubMed: 35636437
DOI: 10.1016/S2666-5247(22)00152-5 -
BMC Genomics Nov 2011Pneumonia and myocarditis are the most commonly reported diseases due to Histophilus somni, an opportunistic pathogen of the reproductive and respiratory tracts of...
BACKGROUND
Pneumonia and myocarditis are the most commonly reported diseases due to Histophilus somni, an opportunistic pathogen of the reproductive and respiratory tracts of cattle. Thus far only a few genes involved in metabolic and virulence functions have been identified and characterized in H. somni using traditional methods. Analyses of the genome sequences of several Pasteurellaceae species have provided insights into their biology and evolution. In view of the economic and ecological importance of H. somni, the genome sequence of pneumonia strain 2336 has been determined and compared to that of commensal strain 129Pt and other members of the Pasteurellaceae.
RESULTS
The chromosome of strain 2336 (2,263,857 bp) contained 1,980 protein coding genes, whereas the chromosome of strain 129Pt (2,007,700 bp) contained only 1,792 protein coding genes. Although the chromosomes of the two strains differ in size, their average GC content, gene density (total number of genes predicted on the chromosome), and percentage of sequence (number of genes) that encodes proteins were similar. The chromosomes of these strains also contained a number of discrete prophage regions and genomic islands. One of the genomic islands in strain 2336 contained genes putatively involved in copper, zinc, and tetracycline resistance. Using the genome sequence data and comparative analyses with other members of the Pasteurellaceae, several H. somni genes that may encode proteins involved in virulence (e.g., filamentous haemaggutinins, adhesins, and polysaccharide biosynthesis/modification enzymes) were identified. The two strains contained a total of 17 ORFs that encode putative glycosyltransferases and some of these ORFs had characteristic simple sequence repeats within them. Most of the genes/loci common to both the strains were located in different regions of the two chromosomes and occurred in opposite orientations, indicating genome rearrangement since their divergence from a common ancestor.
CONCLUSIONS
Since the genome of strain 129Pt was ~256,000 bp smaller than that of strain 2336, these genomes provide yet another paradigm for studying evolutionary gene loss and/or gain in regard to virulence repertoire and pathogenic ability. Analyses of the complete genome sequences revealed that bacteriophage- and transposon-mediated horizontal gene transfer had occurred at several loci in the chromosomes of strains 2336 and 129Pt. It appears that these mobile genetic elements have played a major role in creating genomic diversity and phenotypic variability among the two H. somni strains.
Topics: Chromosomes, Bacterial; Comparative Genomic Hybridization; DNA, Bacterial; Evolution, Molecular; Gene Transfer, Horizontal; Genes, Bacterial; Pasteurellaceae
PubMed: 22111657
DOI: 10.1186/1471-2164-12-570 -
Biomedical and Environmental Sciences :... Jun 2012To establish multiplex PCR-based assays for detecting H.influenzae and H.parainfluenzae. And the PCR-based assays were applied to detect the carriage rates of...
OBJECTIVE
To establish multiplex PCR-based assays for detecting H.influenzae and H.parainfluenzae. And the PCR-based assays were applied to detect the carriage rates of H.influenzae and H.parainfluenzae in nasopharyngeal swab specimens which were collected from healthy children.
METHODS
Multiplex primers for species-specific PCR were designed by using DNAstar soft based on the sequences of 16S rRNA genes from genus Haemophilus to detect H.influenzae and H.parainfluenzae.
RESULTS
The sensitivity of the 16S rRNA PCR assay for detecting H.influenzae and H.parainfluenzae was 97.53% and 100% respectively, and the specificity was 95.89% and 96.63% respectively. Youden's Index on the ability to detect H.influenzae and H.parainfluenzae was 0.9342 and 0.9663 respectively. 666 nasopharyngeal swab specimens were collected from healthy children. The detection rates of H.influenzae and H.parainfluenzae were 14.11% and 16.07% respectively by using isolation and culture methods. The detection rates of H.influenzae and H.parainfluenzae were 43.54% and 57.96% respectively by 16S rRNA PCR assays. The carriage rates of serotypes a, b, c, d, e, f and non-typeable isolates were 0% (0/666), 0.15% (1/666), 1.20% (8/666), 0.15% (1/666), 1.20% (8/666), 1.80% (12/666), 95.50% (636/666) respectively.
CONCLUSION
The multiplex PCR assays were very rapid, reliable and feasible methods for detection of H.influenzae and H.parainfluenzae in pharyngeal swab specimens which were compared to conventional isolation and culture methods. 95.5% of H.influenzae strains in healthy children were nontypeable. The encapsulated or typable strains were mainly three serotypes which was c, e, and f serotype.
Topics: Haemophilus influenzae; Haemophilus parainfluenzae; Humans; Multiplex Polymerase Chain Reaction; Nasopharynx; RNA, Bacterial; RNA, Ribosomal, 16S; Sensitivity and Specificity
PubMed: 22840589
DOI: 10.3967/0895-3988.2012.03.016 -
Journal of the American Association For... Sep 2023Soiled bedding sentinel programs have long been the cornerstone of rodent health monitoring surveillance. Many recent studies have evaluated methods to replace live...
Soiled bedding sentinel programs have long been the cornerstone of rodent health monitoring surveillance. Many recent studies have evaluated methods to replace live animals in these programs; however, the type of ventilated rack being used greatly influences the detection rate of adventitious pathogens. This study evaluated 4 alternative sampling techniques across 5 distinct vivaria and assessed their accuracy in detecting 5 pathogens. Testing was done in an operational (real-world) setting using IVC racks that vent air at the cage level. The 5 agents surveyed were mouse norovirus, spp., spp. , and . Samples were collected for subsequent PCR assays as follows: 1) cages with live sentinels exposed to soiled bedding; 2) filter paper placed on the lid of an unoccupied cage containing soiled bedding; 3) filter paper placed in the bedding of an unoccupied cage that contained soiled bedding; 4) swabs from an unoccupied sentinel cage that contained soiled bedding; and 5) pooled swabs from colony cages admixed with swabs from soiled bedding sentinel mice. Cumulative accuracy for all pathogens of interest was highest with the existing soiled bedding sentinel program, followed by pooled swabs of colony cages mixed with swabs from occupied soiled bedding sentinel cages. Soiled bedding sentinel cages detected mouse norovirus, spp., and S. with the highest accuracy; the pooled swabs were best in detecting Rodentibacter spp. and E. . The findings suggest that with the type of rack and caging used in our facilities, the soiled bedding sentinel method has highest concurrence with the expected health status of an animal room, and the results from this method can be enhanced with the addition of pooled swabs of colony animals.
Topics: Animals; Mice; Housing, Animal; Filtration; Polymerase Chain Reaction; Helicobacter; Pasteurellaceae; Norovirus; Bedding and Linens; Rodent Diseases
PubMed: 37758466
DOI: 10.30802/AALAS-JAALAS-23-000030 -
Medical Microbiology and Immunology Nov 2018Phosphorylcholine (ChoP) is covalently incorporated into bacterial surface structures, contributing to host mimicry and promoting adhesion to surfaces. Our aims were to...
Phosphorylcholine (ChoP) is covalently incorporated into bacterial surface structures, contributing to host mimicry and promoting adhesion to surfaces. Our aims were to determine the frequency of ChoP display among Aggregatibacter actinomycetemcomitans strains, to clarify which surface structures bear ChoP, and whether ChoP-positivity relates to serum killing. The tested oral (N = 67) and blood isolates (N = 27) represented 6 serotypes. Mab TEPC-15 was used for immunoblotting of cell lysates and fractions and for immunofluorescence microscopy of cell surface-bound ChoP. The lysates were denatured with urea for hidden ChoP or treated with proteinase K to test whether it binds to a protein. Three ChoP-positive and two ChoP-negative strains were subjected to serum killing in the presence/absence of CRP and using Ig-depleted serum as complement source. Cell lysates and the first soluble cellular fraction revealed a < 10 kDa band in immunoblots. Among 94 strains, 27 were ChoP positive. No difference was found in the prevalence of ChoP-positive oral (21/67) and blood (6/27) strains. Immunofluorescence microscopy corresponded to the immunoblot results. Proteinase K abolished ChoP reactivity, whereas urea did not change the negative result. The TEPC-15-reactive protein was undetectable in Δflp1 mutant strain. The survival rate of serotype-b strains in serum was 100% irrespective of ChoP, but that of serotype-a was higher in ChoP-positive (85%) than ChoP-negative (71%) strains. The results suggest that a third of rough-colony strains harbor ChoP and that ChoP is attached to fimbrial subunit protein Flp1. It further seems that ChoP-positivity does not enhance but may reduce A. actinomycetemcomitans susceptibility to serum killing.
Topics: Aggregatibacter actinomycetemcomitans; Bacterial Proteins; Blood; Blood Bactericidal Activity; Gene Deletion; Humans; Immunoblotting; Microbial Viability; Microscopy, Fluorescence; Mouth; Pasteurellaceae Infections; Phosphorylcholine; Serogroup
PubMed: 30056510
DOI: 10.1007/s00430-018-0554-1 -
DNA Research : An International Journal... Apr 2018Aggregatibacter actinomycetemcomitans is a major periodontal pathogen that has several virulence factors such as leukotoxin and cytolethal distending toxin. Although the...
Aggregatibacter actinomycetemcomitans is a major periodontal pathogen that has several virulence factors such as leukotoxin and cytolethal distending toxin. Although the genes responsible for virulence have been identified, little is known about their regulatory mechanisms. Small RNA (sRNA) has been recognized as an important factor for gene regulation. To identify new regulatory mechanisms via sRNA in A. actinomycetemcomitans HK1651, we performed a systematic search for sRNAs by RNA-seq and identified 90 intergenic region sRNAs and 30 antisense sRNAs. Of the 85 analysable sRNAs, we successfully detected and quantified 70 sRNAs by developing an RT-PCR system, and we identified 17 sRNAs that were differentially expressed during different growth phases. In addition, we found notable intraspecies variation in the sRNA repertoire of A. actinomycetemcomitans, thus suggesting that frequent acquisition or deletion of sRNAs occurred during the evolution of this species. The predicted target genes of the intergenic region sRNAs indicated the possibility of sRNA interaction with several virulence genes including leukotoxin and cytolethal distending toxin. Our results should serve as an important genomic and genetic basis for future studies to fully understand the regulatory network in A. actinomycetemcomitans and provide new insights into the intraspecies variation of the bacterial sRNA repertoire in bacteria.
Topics: Aggregatibacter actinomycetemcomitans; Gene Expression Regulation, Bacterial; RNA, Bacterial; RNA, Small Untranslated; Sequence Analysis, RNA; Virulence
PubMed: 29211829
DOI: 10.1093/dnares/dsx050