Incidence and molecular detection of Salmonella enterica serogroups and spvC virulence gene in raw and processed meats from selected wet markets in Metro Manila, Philippines

The present study included the detection ofsome virulence factorsof Aeromonas hydrophila under molecular level to clinical isolates were taken from patients suffering from diarrhea during the period from July (2017) to October (2017). Molecular detection of Hemolysin gene (ahh) was done for all isolates. The results showed that all isolates (100%) gave positive results for this virulence gene. the positive results were detected by the presence of (130) bp bands when compared with allelic ladder. The genomic DNA of the samples was extracted and bands were observed by performing agarose gel electrophoresis. When PCR was performed,results clearly indicate that all isolated organisms contained serine protease gene and all the amplified products produced a band at the level of (900 bp) when compared with the allelic ladder. Molecular detection of this gene was carried out by using a specific PCR primer were done by comparison with allelic ladder which gave a (309bp) It was found that (Aerolysin) gene present in (12) (75%) of the positive samples. Lip gene was also detected in A. hydrophila samples and found that all 16 samples (100%) gave positive results to this gene which gave molecular length (382) bp. Molecular study was carried out to show the sequence identity of cytotonic enterotoxins gene in Aeromonas spp. to that in A. hydrophila. Analysis of the A. hydrophila genome revealed a number of a putative virulence factors,including a gene that heat-labile cytotonic enterotoxin (alt). Our study showed that all (16) isolates (100%) gave positive results to this gene,which gave molecular length (442)bp. Molecular detection of cytotonic enterotoxins gene (ast) was done for (16) A. hydrophila isolates and the results showed that all isolates have this gene (100%). The positive results for (ast) virulence were detected by the presence of (331) bp band compared with allelic ladder.

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Diffusible Signal Factors Act through AraC-Type Transcriptional Regulators as Chemical Cues To Repress Virulence of Enteric Pathogens

Infection and Immunity ◽

10.1128/iai.00226-20 ◽

2020 ◽

Vol 88 (10) ◽

Author(s):

Erick Maosa Bosire ◽

Colleen R. Eade ◽

Carl J. Schiltz ◽

Amanda J. Reid ◽

Jerry Troutman ◽

...

Keyword(s):

Gene Expression ◽

Fatty Acids ◽

Salmonella Enterica ◽

Unsaturated Fatty Acids ◽

Virulence Gene ◽

Transcriptional Regulators ◽

Enteric Pathogens ◽

Hexadecenoic Acid ◽

Content Type ◽

Virulence Gene Expression

ABSTRACT Successful colonization by enteric pathogens is contingent upon effective interactions with the host and the resident microbiota. These pathogens thus respond to and integrate myriad signals to control virulence. Long-chain fatty acids repress the virulence of the important enteric pathogens Salmonella enterica and Vibrio cholerae by repressing AraC-type transcriptional regulators in pathogenicity islands. While several fatty acids are known to be repressive, we show here that cis-2-unsaturated fatty acids, a rare chemical class used as diffusible signal factors (DSFs), are highly potent inhibitors of virulence functions. We found that DSFs repressed virulence gene expression of enteric pathogens by interacting with transcriptional regulators of the AraC family. In Salmonella enterica serovar Typhimurium, DSFs repress the activity of HilD, an AraC-type activator essential to the induction of epithelial cell invasion, by both preventing its interaction with target DNA and inducing its rapid degradation by Lon protease. cis-2-Hexadecenoic acid (c2-HDA), a DSF produced by Xylella fastidiosa, was the most potent among those tested, repressing the HilD-dependent transcriptional regulator hilA and the type III secretion effector sopB >200- and 68-fold, respectively. Further, c2-HDA attenuated the transcription of the ToxT-dependent cholera toxin synthesis genes of V. cholerae. c2-HDA significantly repressed invasion gene expression by Salmonella in the murine colitis model, indicating that the HilD-dependent signaling pathway functions within the complex milieu of the animal intestine. These data argue that enteric pathogens respond to DSFs as interspecies signals to identify appropriate niches in the gut for virulence activation, which could be exploited to control the virulence of enteric pathogens.

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Interplay between the QseC and QseE Bacterial Adrenergic Sensor Kinases in Salmonella enterica Serovar Typhimurium Pathogenesis

Infection and Immunity ◽

10.1128/iai.00803-12 ◽

2012 ◽

Vol 80 (12) ◽

pp. 4344-4353 ◽

Cited By ~ 34

Author(s):

Cristiano G. Moreira ◽

Vanessa Sperandio

Keyword(s):

Gene Expression ◽

Epithelial Cells ◽

Salmonella Enterica ◽

Double Mutant ◽

Virulence Gene ◽

Virulence Gene Expression ◽

Regulatory Cascade ◽

Serovar Typhimurium ◽

Sensor Kinases

ABSTRACTThe bacterial adrenergic sensor kinases QseC and QseE respond to epinephrine and/or norepinephrine to initiate a complex phosphorelay regulatory cascade that modulates virulence gene expression in several pathogens. We have previously shown that QseC activates virulence gene expression inSalmonella entericaserovar Typhimurium. Here we report the role of QseE inS. Typhimurium pathogenesis as well as the interplay between these two histidine sensor kinases in gene regulation. AnS. TyphimuriumqseEmutant is hampered in the invasion of epithelial cells and intramacrophage replication. The ΔqseCstrain is highly attenuated for intramacrophage survival but has only a minor defect in invasion. However, the ΔqseECstrain has only a slight attenuation in invasion, mirroring the ΔqseCstrain, and has an intermediary intramacrophage replication defect in comparison to the ΔqseEand ΔqseCstrains. The expressions of thesipAandsopBgenes, involved in the invasion of epithelial cells, are activated by epinephrine via QseE. The expression levels of these genes are still decreased in the ΔqseECdouble mutant, albeit to a lesser extent, congruent with the invasion phenotype of this mutant. The expression level of thesifAgene, important for intramacrophage replication, is decreased in theqseEmutant and the ΔqseECdouble mutant grownin vitro. However, as previously reported by us, the epinephrine-dependent activation of this gene occurs via QseC. In the systemic model ofS. Typhimurium infection of BALB/c mice, theqseCandqseEmutants are highly attenuated, while the double mutant has an intermediary phenotype. Altogether, these data suggest that both adrenergic sensors play an important role in modulating several aspects ofS. Typhimurium pathogenesis.

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Polynucleotide Phosphorylase Negatively Controls spv Virulence Gene Expression in Salmonella enterica

Infection and Immunity ◽

10.1128/iai.74.2.1243-1254.2006 ◽

2006 ◽

Vol 74 (2) ◽

pp. 1243-1254 ◽

Cited By ~ 49

Author(s):

Sofia Eriksson Ygberg ◽

Mark O. Clements ◽

Anne Rytkönen ◽

Arthur Thompson ◽

David W. Holden ◽

...

Keyword(s):

Salmonella Enterica ◽

Cold Shock ◽

Virulence Gene ◽

Growth Conditions ◽

Polynucleotide Phosphorylase ◽

Virulence Gene Expression ◽

Cold Shock Response ◽

Serovar Typhimurium ◽

Whole Genome Microarray

ABSTRACT Mutational inactivation of the cold-shock-associated exoribonuclease polynucleotide phosphorylase (PNPase; encoded by the pnp gene) in Salmonella enterica serovar Typhimurium was previously shown to enable the bacteria to cause chronic infection and to affect the bacterial replication in BALB/c mice (M. O. Clements et al., Proc. Natl. Acad. Sci. USA 99:8784-8789, 2002). Here, we report that PNPase deficiency results in increased expression of Salmonella plasmid virulence (spv) genes under in vitro growth conditions that allow induction of spv expression. Furthermore, whole-genome microarray-based transcriptome analyses of bacteria growing inside murine macrophage-like J774.A.1 cells revealed six genes as being significantly up-regulated in the PNPase-deficient background, which included spvABC, rtcB, entC, and STM2236. Mutational inactivation of the spvR regulator diminished the increased expression of spv observed in the pnp mutant background, implying that PNPase acts upstream of or at the level of SpvR. Finally, competition experiments revealed that the growth advantage of the pnp mutant in BALB/c mice was dependent on spvR as well. Combined, our results support the idea that in S. enterica PNPase, apart from being a regulator of the cold shock response, also functions in tuning the expression of virulence genes and bacterial fitness during infection.

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Molecular Detection of Salmonella enterica subsp. arizonae by Quantitative PCR

Avian Diseases ◽

10.1637/aviandiseases-d-19-00197 ◽

2020 ◽

Vol 64 (3) ◽

Author(s):

Linnea M. Tracy ◽

Jessica A. Hicks ◽

Karen B. Grogan ◽

Jenny A. Nicholds ◽

Brenda R. Morningstar-Shaw ◽

...

Keyword(s):

Quantitative Pcr ◽

Salmonella Enterica ◽

Molecular Detection

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Multiplex PCR–Based Serogrouping and Serotyping of Salmonella enterica from Tonsil and Jejunum with Jejunal Lymph Nodes of Slaughtered Swine in Metro Manila, Philippines

Journal of Food Protection ◽

10.4315/0362-028x.jfp-14-342 ◽

2015 ◽

Vol 78 (5) ◽

pp. 873-880 ◽

Cited By ~ 1

Author(s):

KAMELA CHARMAINE S. NG ◽

WINDELL L. RIVERA

Keyword(s):

Lymph Nodes ◽

Multiplex Pcr ◽

Salmonella Enterica ◽

Food Poisoning ◽

Culture Method ◽

The Philippines ◽

Meat Inspection ◽

Pcr Products ◽

Metro Manila ◽

And Control

Food poisoning outbreaks and livestock mortalities caused by Salmonella enterica are widespread in the Philippines, with hogs being the most commonly recognized carriers of the pathogen. To prevent and control the occurrence of S. enterica infection in the country, methods were used in this study to isolate and rapidly detect, differentiate, and characterize S. enterica in tonsils and jejuna with jejunal lymph nodes of swine slaughtered in four locally registered meat establishments (LRMEs) and four meat establishments accredited by the National Meat Inspection Services in Metro Manila. A total of 480 samples were collected from 240 animals (120 pigs from each type of meat establishment). A significantly higher proportion of pigs were positive for S. enterica in LRMEs (60 of 120) compared with meat establishments accredited by the National Meat Inspection Services (38 of 120). More S. enterica–positive samples were found in tonsils compared with jejuna with jejunal lymph nodes in LRMEs, but this difference was not significant. A PCR assay targeting the invA gene had sensitivity that was statistically similar to that of the culture method, detecting 93 of 98 culture-confirmed samples. Multiplex PCR–based O-serogrouping and H/Sdf I typing revealed four S. enterica serogroups (B, C1, D, and E) and six serotypes (Agona, Choleraesuis, Enteritidis, Heidelberg, Typhimurium, and Weltevreden), respectively, which was confirmed by DNA sequencing of the PCR products. This study was the first to report detection of S. enterica serotype Agona in the country.

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Salmonellain Liquid Eggs and Other Foods in Fukuoka Prefecture, Japan

International Journal of Microbiology ◽

10.1155/2013/463095 ◽

2013 ◽

Vol 2013 ◽

pp. 1-5 ◽

Cited By ~ 7

Author(s):

Koichi Murakami ◽

Tamie Noda ◽

Daisuke Onozuka ◽

Nobuyuki Sera

Keyword(s):

Salmonella Enterica ◽

Culture Method ◽

Human Pathogen ◽

Fukuoka Prefecture ◽

Processed Meats ◽

Dried Fish

The study aimed to evaluate the prevalence ofSalmonellain retail and wholesale foods in Fukuoka Prefecture, Japan. A total of 2,021 samples collected between 1999 and 2010 were tested using a culture method. Samples consisted of liquid eggs (n=30), meat (beef and pork) (n=781), offal (n=69), processed meats (n=2), seafood (n=232), processed seafood (dried fish) (n=76), vegetables (n=481), processed vegetables (n=87), fruits (n=167), and herbs (n=96) from 574 outlets and wholesale agents in 15 areas (five samples were undocumented regarding outlets). Overall, liquid egg showed significantly (P<0.001) higher frequencies ofSalmonellacontamination (13.3%) than beef (1/423, 0.2%) and pork (3/235, 1.3%).Salmonella entericasubsp.entericaserovar Enteritidis, the most common serovar as a human pathogen, were isolated from two liquid egg samples. NoSalmonellawere isolated from seafood and vegetable-related samples including seed sprouts (n=261). In conclusion, liquid egg is a significantSalmonellavehicle, showing a need to continue the vaccination of chickens to preventS.Enteritidis contamination in Japanese eggs. Moreover, further study is needed to evaluateSalmonellacontamination in seed sprouts with more sampling from retailers there.

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Population structure of Salmonella enterica serotype Mbandaka reveals similar virulence potential irrespective of source and phylogenomic stratification

F1000Research ◽

10.12688/f1000research.25540.1 ◽

2020 ◽

Vol 9 ◽

pp. 1142

Author(s):

Linto Antony ◽

Gavin Fenske ◽

Radhey S Kaushik ◽

Tiruvoor G Nagaraja ◽

Milton Thomas ◽

...

Keyword(s):

Population Structure ◽

Multidrug Resistance ◽

Salmonella Enterica ◽

Virulence Gene ◽

Economic Stress ◽

Phylogenomic Analysis ◽

Gene Repertoire ◽

Phenotypic Analysis ◽

Virulence Potential ◽

Foodborne Outbreaks

Background: Salmonella enterica serotype Mbandaka (Salmonella ser. Mbandaka) is a multi-host adapted Non-typhoidal Salmonella (NTS) that can cause foodborne illnesses in human. Outbreaks of Salmonella ser. Mbandaka contributed to the economic stress caused by NTS due to hospitalizations. Whole genome sequencing (WGS)-based phylogenomic analysis facilitates better understanding of the genomic features that may expedite the foodborne spread of Salmonella ser. Mbandaka. Methods: In the present study, we define the population structure, antimicrobial resistance (AMR), and virulence profile of Salmonella ser. Mbandaka using WGS data of more than 400 isolates collected from different parts of the world. We validated the genotypic prediction of AMR and virulence phenotypically using an available set of representative isolates. Results: Phylogenetic analysis of Salmonella ser. Mbandaka using Bayesian approaches revealed clustering of the population into two major groups; however, clustering of these groups and their subgroups showed no pattern based on the host or geographical origin. Instead, we found a uniform virulence gene repertoire in all isolates. Phenotypic analysis on a representative set of isolates showed a similar trend in cell invasion behavior and adaptation to a low pH environment. Both genotypic and phenotypic analysis revealed the carriage of multidrug resistance (MDR) genes in Salmonella ser. Mbandaka. Conclusions: Overall, our results show that the presence of multidrug resistance along with adaptation to broad range of hosts and uniformity in the virulence potential, isolates of Salmonella ser. Mbandaka from any source could have the potential to cause foodborne outbreaks as well as AMR dissemination.

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