scholarly journals Development of a Genomics-Based Approach To Identify Putative Hypervirulent Nontyphoidal Salmonella Isolates: Salmonella enterica Serovar Saintpaul as a Model

mSphere ◽  
2022 ◽  
Author(s):  
Ruixi Chen ◽  
Rachel A. Cheng ◽  
Martin Wiedmann ◽  
Renato H. Orsi
Keyword(s):  
Human Disease ◽  
Salmonella Enterica ◽  
Control Strategies ◽  
High Prevalence ◽  
Clinical Illness ◽  
Source Populations ◽  
Clinical Cases

Not all Salmonella isolates are equally likely to cause human disease, and Salmonella control strategies may unintentionally focus on serovars and subtypes with high prevalence in source populations but are rarely associated with human clinical illness. We describe a framework leveraging WGS data in the NCBI PD database to identify Salmonella subtypes over- and underrepresented among human clinical cases.

PREVALENCE OF CLASS 1 INTEGRONS IN CLINICAL ISOLATES OF NON-TYPHOIDAL $SALMONELLA~ENTERICA$ CIRCULATED IN ARMENIA

2021 ◽  
Vol 55 (1 (254)) ◽  
pp. 58-66
Author(s):  
Magdalina K. Zakharyan
Keyword(s):  
Multidrug Resistance ◽  
Antimicrobial Resistance ◽  
Clinical Significance ◽  
Antimicrobial Therapy ◽  
Salmonella Enterica ◽  
Clinical Isolates ◽  
Class 1 Integron ◽  
Class 1 Integrons ◽  
High Prevalence ◽  
Class 1

A total of 182 non-typhoid Salmonella enterica (NTS) isolates recovered from patients between 1996 and 2014 were included in the current study focused on class 1 integron detection and its association with multidrug resistance (MDR) phenotype. A high prevalence of isolates displaying MDR and penta-resistance (resistance to ampicillin, chloramphenicol, streptomycin, sulfonamide, tetracycline) phenotypes of clinical significance was revealed. Serotype-specific prevalence of antimicrobial resistance as well as class 1 integrons and inserted variable segments was detected in isolates. The results indicated the limitations of current antimicrobial therapy to control infections caused by MDR isolates of NTS, especially belonging to serotype Typhimurium.

Salmonella enterica Serovar Diversity, Distribution, and Prevalence in Public Access Waters from a Central California Coastal Leafy Green Growing Region during 2011 - 2016

2021 ◽  
Author(s):  
Lisa Gorski ◽  
Anita S. Liang ◽  
Samarpita Walker ◽  
Diana Carychao ◽  
Ashley Aviles Noriega ◽  
...  
Keyword(s):  
United States ◽  
Salmonella Enterica ◽  
The United States ◽  
Public Access ◽  
Bias Analysis ◽  
Central California ◽  
High Prevalence ◽  
Human Salmonellosis ◽  
Rain Events ◽  
Growing Region

Prevalence and serovar diversity of Salmonella enterica was measured during a five-year survey of surface waters in a 500 mi^2 agricultural region of the Central California Coast. Rivers, streams, lakes, and ponds were sampled bimonthly resulting in 2,979 samples. Overall prevalence was 56.4% with higher levels detected in Spring than in Fall. Small, but significant, differences in prevalence were detected based on sample locations. Detection of Salmonella was correlated positively with both significant rain events and, in some environments, levels of generic Escherichia coli . Analysis of 1,936 isolates revealed significant serovar diversity, with 91 different serovars detected. The most common isolated serovars were S. enterica subsp. enterica serovars I 6,8:d:- (406 isolates, 21.0%, and potentially monophasic Salmonella Muenchen), Give (334 isolates, 17.3%), Muenchen (158 isolates, 8.2%), Typhimurium (227 isolates, 11.7%), Oranienburg (106 isolates, 5.5%), and Montevideo (78 isolates, 4%). Sixteen of the 24 most common serovars detected in the region are among the serovars reported to cause the most human salmonellosis in the United States. Some of the serovars were associated with location and seasonal bias. Analysis of Xba I Pulsed Field Gel Electrophoresis (PFGE) patterns of strains of serovars Typhimurium, Oranienburg, and Montevideo showed significant intra-serovar diversity. PFGE pulsotypes were identified in the region for multiple years of the survey, indicating persistence or regular re-introduction to the region. Importance Non-typhoidal Salmonella is the among the leading causes of bacterial foodborne illness and increasing numbers of outbreaks and recalls are due to contaminated produce. High prevalence and 91 different serovars were detected in this leafy green growing region. Seventeen serovars that cause most of the human salmonellosis in the United States were detected, with 16 of those serovars detected in multiple locations and multiple years of the 5-year survey. Understanding the widespread prevalence and diversity of Salmonella in the region will assist in promoting food safety practices and intervention methods for growers and regulators.

scholarly journals In Vitro and In Vivo Assessment of Salmonella enterica Serovar Typhimurium DT104 Virulence

2001 ◽  
Vol 69 (7) ◽  
pp. 4673-4677 ◽  
Author(s):  
Chris A. Allen ◽  
Paula J. Fedorka-Cray ◽  
Andrés Vazquez-Torres ◽  
Mitsu Suyemoto ◽  
Craig Altier ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Phage Type ◽  
Multidrug Resistant ◽  
Peritoneal Macrophages ◽  
Lethal Infection ◽  
Animal Infection ◽  
Serovar Typhimurium ◽  
Clinical Illness

ABSTRACT Multidrug-resistant Salmonella enterica serovar Typhimurium phage type DT104 has become a widespread cause of human and other animal infection worldwide. The severity of clinical illness inS. enterica serovar Typhimurium DT104 outbreaks has led to the suggestion that this strain possesses enhanced virulence. In the present study, in vitro and in vivo virulence-associated phenotypes of several clinical isolates of S. enterica serovar Typhimurium DT104 were examined and compared to S. entericaserovar Typhimurium ATCC 14028s. The ability of these DT104 isolates to survive within murine peritoneal macrophages, invade cultured epithelial cells, resist antimicrobial actions of reactive oxygen and nitrogen compounds, and cause lethal infection in mice were assessed. Our results failed to demonstrate that S. enterica serovar Typhimurium DT104 isolates are more virulent than S. enterica serovar Typhimurium ATCC 14028s.

scholarly journals Municipal Wastewater Surveillance Revealed a High Community Disease Burden of a Rarely Reported and Possibly Subclinical Salmonella enterica Serovar Derby Strain

2020 ◽  
Vol 86 (17) ◽  
Author(s):  
Sabrina Diemert ◽  
Tao Yan
Keyword(s):  
Infectious Disease ◽  
Salmonella Enterica ◽  
Disease Burden ◽  
Municipal Wastewater ◽  
Enteric Pathogens ◽  
Whole Genome Sequencing Data ◽  
Subclinical Infection ◽  
Infection Rates ◽  
Sampling Campaign ◽  
Clinical Cases

ABSTRACT Clinical surveillance of enteric pathogens like Salmonella is integral to track outbreaks and endemic disease trends. However, clinic-centered disease monitoring biases toward detection of severe cases and underestimates the incidence of self-limiting gastroenteritis and asymptomatic strains. Monitoring pathogen loads and diversity in municipal wastewater (MW) can provide insight into asymptomatic or subclinical infections which are not reflected in clinical cases. Subclinical infection patterns may explain the unusual observation from a year-long sampling campaign in Hawaii: Salmonella enterica serovar Derby was the most abundant pulsotype in MW but was detected infrequently in clinics over the sampling period. Using whole-genome sequencing data of Salmonella isolates from MW and public databases, we demonstrate that the Derby serovar has lower virulence potential than other clinical serovars, particularly based on its reduced profile of genes linked with immune evasion and symptom production, suggesting its potential as a subclinical salmonellosis agent. Furthermore, MW had high abundance of a rare Derby sequence type (ST), ST-72 (rather than the more common ST-40). ST-72 isolates had higher frequencies of fimbrial adherence genes than ST-40 isolates; these are key virulence factors involved in colonization and persistence of infections. However, ST-72 isolates lack the Derby-specific Salmonella pathogenicity island 23 (SPI-23), which invokes host immune responses. In combination, ST-72’s genetic features may lead to appreciable infection rates without obvious symptom production, allowing for subclinical persistence in the community. This study demonstrated wastewater’s capability to provide community infectious disease information—such as background infection rates of subclinical enteric illness—which is otherwise inaccessible through clinical approaches. IMPORTANCE Wastewater-based epidemiology (WBE) has been conventionally used to analyze community health via the detection of chemicals, such as legal and illicit drugs; however, municipal wastewater contains microbiological determinants of health and disease as well, including enteric pathogens. Here, we demonstrate that WBE can be used to examine subclinical community salmonellosis patterns. Derby was the most abundant Salmonella serovar detected in Hawaii wastewater over a year-long sampling study, with few corresponding clinical cases. Comparative genomics analyses indicate that the normally rare strain of S. Derby found in wastewater has a unique combination of genes which allow it to persist as a subclinical infection without producing symptoms of severe gastroenteritis. This study shows that WBE can be used to explore trends in community infectious disease patterns which may not be reflected in clinical monitoring, shedding light on overall enteric disease burden and rates of asymptomatic cases.

scholarly journals Persistence of S. typhimurium in a large dairy herd

1989 ◽  
Vol 103 (2) ◽  
pp. 235-241 ◽  
Author(s):  
N. Giles ◽  
Sheilagh A. Hopper ◽  
C. Wray
Keyword(s):  
Mammary Gland ◽  
Salmonella Typhimurium ◽  
Human Disease ◽  
Dairy Herd ◽  
Milk Samples ◽  
The Times ◽  
Clinical Cases

SUMMARYSalmonella typhimurium 49a infection in a large dairy herd persisted for 3·5 years. Illness initially occurred in cows and calves but latterly although there were fewer clinical cases milk filters were culturally positive on 26 out of 73 samplings. Three associated human disease incidents occurred. Individual milk samples identified one cow as an excreter and the organism was recovered from the mammary gland of this animal at slaughter. Correlation between calving pattern, the times of calving and the occurrence of positive milk filters suggest that the cow may have been excreting the organism intermittently from the udder for 2·5 years.

Biofilm Formation and Morphotypes of Salmonella enterica subsp. arizonae Differs from Those of Other Salmonella enterica Subspecies in Isolates from Poultry Houses

2016 ◽  
Vol 79 (7) ◽  
pp. 1127-1134 ◽  
Author(s):  
A. LAMAS ◽  
I. C. FERNANDEZ-NO ◽  
J. M. MIRANDA ◽  
B. VÁZQUEZ ◽  
A. CEPEDA ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Biofilm Formation ◽  
Public Health Problem ◽  
Nutrient Concentrations ◽  
Cellulose Production ◽  
Biofilm Production ◽  
Poultry Houses ◽  
High Prevalence ◽  
Different Temperatures ◽  
Strain Dependent

ABSTRACT Salmonella serovars are responsible for foodborne diseases around the world. The ability to form biofilms allows microorganisms to survive in the environment. In this study, 73 Salmonella strains, belonging to four different subspecies, were isolated from poultry houses and foodstuffs and tested. Biofilm formation was measured at four different temperatures and two nutrient concentrations. Morphotypes and cellulose production were evaluated at three different temperatures. The presence of several genes related to biofilm production was also examined. All strains and subspecies of Salmonella had the ability to form biofilms, and 46.57% of strains produced biofilms under all conditions tested. Biofilm formation was strain dependent and varied according to the conditions. This is the first study to analyze biofilm formation in a wide number of Salmonella enterica subsp. arizonae strains, and no direct relationship between the high prevalence of Salmonella enterica subsp. arizonae strains and their ability to form biofilm was established. Morphotypes and cellulose production varied as the temperature changed, with 20°C being the optimum temperature for expression of the red, dry, and rough morphotype and cellulose. Salmonella enterica subsp. arizonae, whose morphotype is poorly studied, only showed a smooth and white morphotype and lacked the csgD and gcpA genes that are implicated in biofilm production. Thus, Salmonella biofilm formation under different environmental conditions is a public health problem because it can survive and advance through the food chain to reach the consumer.

scholarly journals The Molecular Study of Antibiotic Resistance to Quinolones in Salmonella enterica Strains Isolated in Tehran, Iran

2017 ◽  
Vol 11 (1) ◽  
pp. 189-194 ◽  
Author(s):  
Shirin Malehmir ◽  
Reza Ranjbar ◽  
Naser Harzandi
Keyword(s):  
Nalidixic Acid ◽  
Salmonella Enterica ◽  
Gastrointestinal Disease ◽  
Medical Center ◽  
Molecular Study ◽  
Quinolone Resistance ◽  
Microbiological Methods ◽  
Increased Risk ◽  
High Prevalence ◽  
S Genes

Introduction:Salmonellais known as one of the most important causes of gastrointestinal disease in the world. Quinolones and fluoroquinolones are used successfully in the treatment of salmonellosis particularly for infections that have become resistant to several antibiotics. But non-susceptible isolates to quinolones have been reported in several countries. The data are limited about the prevalence of quinolone-resistant isolates in our country. Therefore, this study investigated the plasmid-mediated quinolone resistance genes inSalmonella entericaisolated in Children's Medical Center in Tehran during 2014-2015.Methods and Materials:Salmonellaisolates were isolated and identified using standard microbiological methods. Antibiotic susceptibility testing and screening ofSalmonellastrains resistant to quinolones were performed according to the CLSI guidelines. The molecular investigation was done using specific primers for detection of qnr genes including:qnrA,qnrB andqnrS, by polymerase chain reaction.Results:Overall, 92 (66.6%) strains were resistant to nalidixic acid. None of the strains showed resistance to ciprofloxacin. Out of the 92 nalidixic acid resistant strains, 52 (56.52%) harboredqnrS genes, 15 strains (16.30%) had bothqnrA andqnrS genes. Two (1.1%) isolates were positive forqnrB gene. Twenty four (26.08%) nalidixic acid resistant isolates did not have any qnr qens.Conclusion:The results of this study show high prevalence of resistance to nalidixic and qnr genes inSalmonellaisolates. Plasmid nature of this type of resistance poses an increased risk of dissemination of quinolone resistance betweenSalmonellaand non-Salmonellaisolates circulating in hospitals environments.

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