ESBL-Producing Salmonella enterica Serovar Typhi in Traveler Returning from Guatemala to Spain

PubMed Central

Piedra-Carrasco, Nuria; Salvador, Fernando; Rodríguez, Virginia; Sánchez-Montalvá, Adrián; Planes, Anna M.; Molina, Israel; Larrosa, M. Nieves

2014-01-01

We report a case of typhoid fever in a traveler returning to Spain from Guatemala that was caused by Salmonella enterica serovar Typhi which produced an extended-spectrum β-lactamase (ESBL). This finding demonstrates the presence of ESBL-producing S. enterica ser. Typhi strains in the Americas. Enhanced surveillance is necessary to prevent further spread. PMID:25340972

Prevalence of current patterns and predictive trends of multidrug-resistant Salmonella Typhi in Sudan.

PubMed

Elshayeb, Ayman A; Ahmed, Abdelazim A; El Siddig, Marmar A; El Hussien, Adil A

2017-11-14

Enteric fever has persistence of great impact in Sudanese public health especially during rainy season when the causative agent Salmonella enterica serovar Typhi possesses pan endemic patterns in most regions of Sudan - Khartoum. The present study aims to assess the recent state of antibiotics susceptibility of Salmonella Typhi with special concern to multidrug resistance strains and predict the emergence of new resistant patterns and outbreaks. Salmonella Typhi strains were isolated and identified according to the guidelines of the International Standardization Organization and the World Health Organization. The antibiotics susceptibilities were tested using the recommendations of the Clinical Laboratories Standards Institute. Predictions of emerging resistant bacteria patterns and outbreaks in Sudan were done using logistic regression, forecasting linear equations and in silico simulations models. A total of 124 antibiotics resistant Salmonella Typhi strains categorized in 12 average groups were isolated, different patterns of resistance statistically calculated by (y = ax - b). Minimum bactericidal concentration's predication of resistance was given the exponential trend (y = n e x ) and the predictive coefficient R 2  > 0 < 1 are approximately alike. It was assumed that resistant bacteria occurred with a constant rate of antibiotic doses during the whole experimental period. Thus, the number of sensitive bacteria decreases at the same rate as resistant occur following term to the modified predictive model which solved computationally. This study assesses the prediction of multi-drug resistance among S. Typhi isolates by applying low cost materials and simple statistical methods suitable for the most frequently used antibiotics as typhoid empirical therapy. Therefore, bacterial surveillance systems should be implemented to present data on the aetiology and current antimicrobial drug resistance patterns of community-acquired agents causing outbreaks.

Salmonella Typhi sense host neuroendocrine stress hormones and release the toxin haemolysin E

PubMed Central

Karavolos, Michail H; Bulmer, David M; Spencer, Hannah; Rampioni, Giordano; Schmalen, Ira; Baker, Stephen; Pickard, Derek; Gray, Joe; Fookes, Maria; Winzer, Klaus; Ivens, Alasdair; Dougan, Gordon; Williams, Paul; Khan, C M Anjam

2011-01-01

Salmonella enterica serovar Typhi (S. typhi) causes typhoid fever. We show that exposure of S. typhi to neuroendocrine stress hormones results in haemolysis, which is associated with the release of haemolysin E in membrane vesicles. This effect is attributed to increased expression of the small RNA micA and RNA chaperone Hfq, with concomitant downregulation of outer membrane protein A. Deletion of micA or the two-component signal-transduction system, CpxAR, abolishes the phenotype. The hormone response is inhibited by the β-blocker propranolol. We provide mechanistic insights into the basis of neuroendocrine hormone-mediated haemolysis by S. typhi, increasing our understanding of inter-kingdom signalling. PMID:21331094

Role of Environmental Factors in Shaping Spatial Distribution of Salmonella enterica Serovar Typhi, Fiji.

PubMed

de Alwis, Ruklanthi; Watson, Conall; Nikolay, Birgit; Lowry, John H; Thieu, Nga Tran Vu; Van, Tan Trinh; Ngoc, Dung Tran Thi; Rawalai, Kitione; Taufa, Mere; Coriakula, Jerimaia; Lau, Colleen L; Nilles, Eric J; Edmunds, W John; Kama, Mike; Baker, Stephen; Cano, Jorge

2018-02-01

Fiji recently experienced a sharp increase in reported typhoid fever cases. To investigate geographic distribution and environmental risk factors associated with Salmonella enterica serovar Typhi infection, we conducted a cross-sectional cluster survey with associated serologic testing for Vi capsular antigen-specific antibodies (a marker for exposure to Salmonella Typhi in Fiji in 2013. Hotspots with high seroprevalence of Vi-specific antibodies were identified in northeastern mainland Fiji. Risk for Vi seropositivity increased with increased annual rainfall (odds ratio [OR] 1.26/quintile increase, 95% CI 1.12-1.42), and decreased with increased distance from major rivers and creeks (OR 0.89/km increase, 95% CI 0.80-0.99) and distance to modeled flood-risk areas (OR 0.80/quintile increase, 95% CI 0.69-0.92) after being adjusted for age, typhoid fever vaccination, and home toilet type. Risk for exposure to Salmonella Typhi and its spatial distribution in Fiji are driven by environmental factors. Our findings can directly affect typhoid fever control efforts in Fiji.

Role of Environmental Factors in Shaping Spatial Distribution of Salmonella enterica Serovar Typhi, Fiji

PubMed Central

Watson, Conall; Nikolay, Birgit; Lowry, John H.; Thieu, Nga Tran Vu; Van, Tan Trinh; Ngoc, Dung Tran Thi; Rawalai, Kitione; Taufa, Mere; Coriakula, Jerimaia; Lau, Colleen L.; Nilles, Eric J.; Edmunds, W. John; Kama, Mike; Baker, Stephen; Cano, Jorge

2018-01-01

Fiji recently experienced a sharp increase in reported typhoid fever cases. To investigate geographic distribution and environmental risk factors associated with Salmonella enterica serovar Typhi infection, we conducted a cross-sectional cluster survey with associated serologic testing for Vi capsular antigen–specific antibodies (a marker for exposure to Salmonella Typhi in Fiji in 2013. Hotspots with high seroprevalence of Vi-specific antibodies were identified in northeastern mainland Fiji. Risk for Vi seropositivity increased with increased annual rainfall (odds ratio [OR] 1.26/quintile increase, 95% CI 1.12–1.42), and decreased with increased distance from major rivers and creeks (OR 0.89/km increase, 95% CI 0.80–0.99) and distance to modeled flood-risk areas (OR 0.80/quintile increase, 95% CI 0.69–0.92) after being adjusted for age, typhoid fever vaccination, and home toilet type. Risk for exposure to Salmonella Typhi and its spatial distribution in Fiji are driven by environmental factors. Our findings can directly affect typhoid fever control efforts in Fiji. PMID:29350150

Activity of Kaempferia pandurata (Roxb.) rhizome ethanol extract against MRSA, MRCNS, MSSA, Bacillus subtilis and Salmonella typhi.

PubMed

Sukandar, Elin Yulinah; Sunderam, Nethiyakalyani; Fidrianny, Irda

2014-01-01

Temu kunci (Kaempferia pandurata (Roxb.)) has a number of benefits and one of these is antibacterial. The rhizome is said to have antibacterial activity against Streptococcus mutans, Lactocillus sp. and Candida albicans. The aim of the study is to test the antibacterial activity of Kaempferia pandurata (Roxb.) rhizome ethanol extract on methicillin-resistant Staphylococcus aureus (MRSA), methicillin-resistant coagulase negative Staphylococci (MRCNS), methicillin-sensitive Staphylococcus aureus (MSSA), Bacillus subtilis and Salmonella typhi. Antimicrobial activity of the extract was assayed by the microdilution method using Mueller Hinton Broth with sterilized 96 round-bottomed microwells to determine the Minimum Inhibitory Concentration (MIC) as well as to determine the time-kill activity. The MIC of the extract was 16 ppm for both Bacillus subtilis and MRSA; 8 ppm for both MSSA and Salmonella typhi and 4 ppm for MRCNS. Ethanol extract of Kaempferia pandurata (Roxb.) showed antibacterial activity against all the tested bacteria and was the most potent against MRCNS, with MIC 4 ppm. The killing profile test of the extract displayed bactericidal activity at 8-16 ppm against MRSA, MSSA, Bacillus subtilis and Salmonella typhi and bacteriostatic activity at 4 ppm towards MRCNS.

A multiplex single nucleotide polymorphism typing assay for detecting mutations that result in decreased fluoroquinolone susceptibility in Salmonella enterica serovars Typhi and Paratyphi A

PubMed Central

Song, Yajun; Roumagnac, Philippe; Weill, François-Xavier; Wain, John; Dolecek, Christiane; Mazzoni, Camila J.; Holt, Kathryn E.; Achtman, Mark

2010-01-01

Objectives Decreased susceptibility to fluoroquinolones has become a major problem for the successful therapy of human infections caused by Salmonella enterica, especially the life-threatening typhoid and paratyphoid fevers. Methods By using Luminex xTAG beads, we developed a rapid, reliable and cost-effective multiplexed genotyping assay for simultaneously detecting 11 mutations in gyrA, gyrB and parE of S. enterica serovars Typhi and Paratyphi A that result in nalidixic acid resistance (NalR) and/or decreased susceptibility to fluoroquinolones. Results This assay yielded unambiguous single nucleotide polymorphism calls on extracted DNA from 292 isolates of Salmonella Typhi (NalR = 223 and NalS = 69) and 106 isolates of Salmonella Paratyphi A (NalR = 24 and NalS = 82). All of the 247 NalR Salmonella Typhi and Salmonella Paratyphi A isolates were found to harbour at least one of the target mutations, with GyrA Phe-83 as the most common one (143/223 for Salmonella Typhi and 18/24 for Salmonella Paratyphi A). We also identified three GyrB mutations in eight NalS Salmonella Typhi isolates (six for GyrB Phe-464, one for GyrB Leu-465 and one for GyrB Asp-466), and mutations GyrB Phe-464 and GyrB Asp-466 seem to be related to the decreased ciprofloxacin susceptibility phenotype in Salmonella Typhi. This assay can also be used directly on boiled single colonies. Conclusions The assay presented here would be useful for clinical and reference laboratories to rapidly screen quinolone-resistant isolates of Salmonella Typhi and Salmonella Paratyphi A, and decipher the underlying genetic changes for epidemiological purposes. PMID:20511368

Biofilm Producing Salmonella Typhi: Chronic Colonization and Development of Gallbladder Cancer

PubMed Central

Cavallo, Ilaria; Pontone, Martina; Toma, Luigi; Ensoli, Fabrizio

2017-01-01

Salmonella enterica subspecies enterica serovar Typhi is the aetiological agent of typhoid or enteric fever. In a subset of individuals, S. Typhi colonizes the gallbladder causing an asymptomatic chronic infection. Nonetheless, these asymptomatic carriers provide a reservoir for further spreading of the disease. Epidemiological studies performed in regions where S. Typhi is endemic, revealed that the majority of chronically infected carriers also harbour gallstones, which in turn, have been indicated as a primary predisposing factor for the onset of gallbladder cancer (GC). It is now well recognised, that S. Typhi produces a typhoid toxin with a carcinogenic potential, that induces DNA damage and cell cycle alterations in intoxicated cells. In addition, biofilm production by S. Typhi may represent a key factor for the promotion of a persistent infection in the gallbladder, thus sustaining a chronic local inflammatory response and exposing the epithelium to repeated damage caused by carcinogenic toxins. This review aims to highlight the putative connection between the chronic colonization by highly pathogenic strains of S. Typhi capable of combining biofilm and toxin production and the onset of GC. Considering the high risk of GC associated with the asymptomatic carrier status, the rapid identification and profiling of biofilm production by S. Typhi strains would be key for effective therapeutic management and cancer prevention. PMID:28858232

Multiplex quantification of Escherichia coli, Salmonella typhi and Vibrio cholera with three DNA targets in single reaction assay.

PubMed

Jangampalli Adi, Pradeepkiran; Naidu, Jagadish R; Matcha, Bhaskar

2017-09-01

Escherichia coli (E. coli), Salmonella typhi and Vibrio cholera harmful pathogens, which causes various diseases in humans. Rapid diagnosis of bacterial infection is an important for patient management and appropriate therapy during the early phase of the bacterial infected diseases. Among the existing techniques for identifying pathogens were less sensitive and time-consuming processes. In the present study total, 48 clinical 31 blood and 17 urine samples of patients suspected with the infections were collected from SVRR Hospital and used to detect the pathogens. Multiplex polymerase chain reaction (PCR) assay was set to design for the identification of Escherichia coli, Salmonella typhi and Vibrio cholera from the different clinical samples. Rapid diagnosis of Escherichia coli (E. coli), Salmonella and Vibrio cholera pathogens can be done with simultaneously in a single multiplex PCR assay by using specific primers with adjusted PCR conditions. Through this approach, the results represented with out of 31 blood samples 1-15 shows the positive with E. coli and remaining 14 only 11 were correlated with multiplex results of Vibrio cholera, remaining the urine samples all are positive with 17 samples correlate with the Salmonella typhi. Through the high specificity benefits of excellent sensitivity, with high resolution and reproducibility. This method of results proved and illustrates the best potential system for diagnosing the infectious disease with modern trendy. Copyright © 2017 Elsevier Ltd. All rights reserved.

Ciprofloxacin-resistant Salmonella enterica Serotype Typhi, United States, 1999-2008.

PubMed

Medalla, Felicita; Sjölund-Karlsson, Maria; Shin, Sanghyuk; Harvey, Emily; Joyce, Kevin; Theobald, Lisa; Nygren, Benjamin N; Pecic, Gary; Gay, Kathryn; Austin, Jana; Stuart, Andrew; Blanton, Elizabeth; Mintz, Eric D; Whichard, Jean M; Barzilay, Esra J

2011-06-01

We report 9 ciprofloxacin-resistant Salmonella enterica serotype Typhi isolates submitted to the US National Antimicrobial Resistance Monitoring System during 1999-2008. The first 2 had indistinguishable pulsed-field gel electrophoresis patterns and identical gyrA and parC mutations. Eight of the 9 patients had traveled to India within 30 days before illness onset.

Laboratory-acquired infections of Salmonella enterica serotype Typhi in South Africa: phenotypic and genotypic analysis of isolates.

PubMed

Smith, Anthony Marius; Smouse, Shannon Lucrecia; Tau, Nomsa Pauline; Bamford, Colleen; Moodley, Vineshree Mischka; Jacobs, Charlene; McCarthy, Kerrigan Mary; Lourens, Adré; Keddy, Karen Helena

2017-09-29

Workers in clinical microbiology laboratories are exposed to a variety of pathogenic microorganisms. Salmonella species is among the most commonly reported bacterial causes of laboratory-acquired infections. We report on three cases of laboratory-acquired Salmonella enterica serotype Typhi (Salmonella Typhi) infection which occurred over the period 2012 to 2016 in South Africa. Laboratory investigation included phenotypic and genotypic characterization of isolates. Phenotypic analysis included standard microbiological identification techniques, serotyping and antimicrobial susceptibility testing. Genotypic analysis included the molecular subtyping methodologies of pulsed-field gel electrophoresis analysis, multilocus sequence typing and whole-genome sequencing (WGS); with WGS data analysis including phylogenetic analysis based upon comparison of single nucleotide polymorphism profiles of isolates. All cases of laboratory-acquired infection were most likely the result of lapses in good laboratory practice and laboratory safety. The following critical issues were highlighted. There was misdiagnosis and misreporting of Salmonella Typhi as nontyphoidal Salmonella by a diagnostic laboratory, with associated public health implications. We highlight issues concerning the importance of accurate fluoroquinolone susceptibility testing and interpretation of results according to updated guidelines. We describe potential shortcomings of a single disk susceptibility screening test for fluoroquinolone susceptibility and suggest that confirmatory minimum inhibitory concentration testing should always be performed in cases of invasive Salmonella infections. These antimicrobial susceptibility testing issues resulted in inappropriate ciprofloxacin therapy which may have been responsible for failure in clearance of pathogen from patients. Salmonella Typhi capsular polysaccharide vaccine was not protective in one case, possibly secondarily to a faulty vaccine. Molecular subtyping of

Response of Salmonella Typhi to bile-generated oxidative stress: implication of quorum sensing and persister cell populations.

PubMed

Walawalkar, Yogesh D; Vaidya, Yatindra; Nayak, Vijayashree

2016-11-01

Salmonella Typhi can chronically persist within the gallbladder of patients suffering from gallbladder diseases. This study, intended to improve our understanding of bacterial mechanisms underlying bile adaptation, revealed that bile, which is a bactericidal agent, led to the generation of reactive oxygen species in S Typhi. Salmonella Typhi in response showed a significant increase in the production of anti-oxidative enzymes, namely superoxide dismutase and catalase. The work reports that the quorum-sensing (QS) system of S Typhi regulates the level of these enzymes during oxidative stress. In support of these observations, the quorum-sensing mutant of S Typhi was found to be sensitive to bile with significantly lower levels of anti-oxidant enzymes compared to other clinical isolates. Furthermore the addition of exogenous cell-free extracts (CFEs) of S Typhi containing the quorum-sensing signalling molecule significantly increased the levels of these enzymes within the mutant. Interestingly the CFE addition did not significantly restore the biofilm-forming ability of the mutant strain when compared with the wild-type. In the presence of ciprofloxacin and ampicillin, S Typhi formed persister cells which increased >3-fold in the presence of bile. Thus the QS-system of S Typhi aids in oxidative stress management, and enhanced persister cell populations could assist chronic bacterial persistence within the gallbladder. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Fitness benefits in fluoroquinolone-resistant Salmonella Typhi in the absence of antimicrobial pressure

PubMed Central

Baker, Stephen; Duy, Pham Thanh; Nga, Tran Vu Thieu; Dung, Tran Thi Ngoc; Phat, Voong Vinh; Chau, Tran Thuy; Turner, A Keith; Farrar, Jeremy; Boni, Maciej F

2013-01-01

Fluoroquinolones (FQ) are the recommended antimicrobial treatment for typhoid, a severe systemic infection caused by the bacterium Salmonella enterica serovar Typhi. FQ-resistance mutations in S. Typhi have become common, hindering treatment and control efforts. Using in vitro competition experiments, we assayed the fitness of eleven isogenic S. Typhi strains with resistance mutations in the FQ target genes, gyrA and parC. In the absence of antimicrobial pressure, 6 out of 11 mutants carried a selective advantage over the antimicrobial-sensitive parent strain, indicating that FQ resistance in S. Typhi is not typically associated with fitness costs. Double-mutants exhibited higher than expected fitness as a result of synergistic epistasis, signifying that epistasis may be a critical factor in the evolution and molecular epidemiology of S. Typhi. Our findings have important implications for the management of drug-resistant S. Typhi, suggesting that FQ-resistant strains would be naturally maintained even if fluoroquinolone use were reduced. DOI: http://dx.doi.org/10.7554/eLife.01229.001 PMID:24327559

Differential roles for pathogenicity islands SPI-13 and SPI-8 in the interaction of Salmonella Enteritidis and Salmonella Typhi with murine and human macrophages.

PubMed

Espinoza, Rodrigo A; Silva-Valenzuela, Cecilia A; Amaya, Fernando A; Urrutia, Ítalo M; Contreras, Inés; Santiviago, Carlos A

2017-02-15

Salmonella pathogenicity island (SPI)-13 is conserved in many serovars of S. enterica, including S. Enteritidis, S. Typhimurium and S. Gallinarum. However, it is absent in typhoid serovars such as S. Typhi and Paratyphi A, which carry SPI-8 at the same genomic location. Because the interaction with macrophages is a critical step in Salmonella pathogenicity, in this study we investigated the role played by SPI-13 and SPI-8 in the interaction of S. Enteritidis and S. Typhi with cultured murine (RAW264.7) and human (THP-1) macrophages. Our results showed that SPI-13 was required for internalization of S. Enteritidis in murine but not human macrophages. On the other hand, SPI-8 was not required for the interaction of S. Typhi with human or murine macrophages. Of note, the presence of an intact copy of SPI-13 in a S. Typhi mutant carrying a deletion of SPI-8 did not improve its ability to be internalized by, or survive in human or murine macrophages. Altogether, our results point out to different roles for SPI-13 and SPI-8 during Salmonella infection. While SPI-13 contributes to the interaction of S. Enteritidis with murine macrophages, SPI-8 is not required in the interaction of S. Typhi with murine or human macrophages. We hypothesized that typhoid serovars have lost SPI-13 and maintained SPI-8 to improve their fitness during another phase of human infection.

Host adaptation of a bacterial toxin from the human pathogen Salmonella Typhi

PubMed Central

Deng, Lingquan; Song, Jeongmin; Gao, Xiang; Wang, Jiawei; Yu, Hai; Chen, Xi; Varki, Nissi; Naito-Matsui, Yuko; Galán, Jorge E.; Varki, Ajit

2014-01-01

Salmonella Typhi is an exclusive human pathogen that causes typhoid fever. Typhoid toxin is a S. Typhi virulence factor that can reproduce most of the typhoid fever symptoms in experimental animals. Toxicity depends on toxin binding to terminally sialylated glycans on surface glycoproteins. Human glycans are unusual because of the lack of CMAH, which in other mammals converts N-acetylneuraminic acid (Neu5Ac) to N-glycolylneuraminic acid (Neu5Gc). Here we report that typhoid toxin binds to and is toxic towards cells expressing glycans terminated in Neu5Ac (expressed by humans) over glycans terminated in Neu5Gc (expressed by other mammals). Mice constitutively expressing CMAH thus displaying Neu5Gc in all tissues are resistant to typhoid toxin. The atomic structure of typhoid toxin bound to Neu5Ac reveals the structural bases for its binding specificity. These findings provide insight into the molecular bases for Salmonella Typhi’s host specificity and may help the development of therapies for typhoid fever. PMID:25480294

Ciprofloxacin-Resistant Salmonella enterica Serotype Typhi, United States, 1999–2008

PubMed Central

Sjölund-Karlsson, Maria; Shin, Sanghyuk; Harvey, Emily; Joyce, Kevin; Theobald, Lisa; Nygren, Benjamin L.; Pecic, Gary; Gay, Kathryn; Austin, Jana; Stuart, Andrew; Blanton, Elizabeth; Mintz, Eric D.; Whichard, Jean M.; Barzilay, Ezra J.

2011-01-01

We report 9 ciprofloxacin-resistant Salmonella enterica serotype Typhi isolates submitted to the US National Antimicrobial Resistance Monitoring System during 1999–2008. The first 2 had indistinguishable pulsed-field gel electrophoresis patterns and identical gyrA and parC mutations. Eight of the 9 patients had traveled to India within 30 days before illness onset. PMID:21749779

An extended genotyping framework for Salmonella enterica serovar Typhi, the cause of human typhoid

PubMed Central

Wong, Vanessa K.; Baker, Stephen; Connor, Thomas R.; Pickard, Derek; Page, Andrew J.; Dave, Jayshree; Murphy, Niamh; Holliman, Richard; Sefton, Armine; Millar, Michael; Dyson, Zoe A.; Dougan, Gordon; Holt, Kathryn E.; Parkhill, Julian; Feasey, Nicholas A.; Kingsley, Robert A.; Thomson, Nicholas R.; Keane, Jacqueline A.; Weill, François- Xavier; Le Hello, Simon; Hawkey, Jane; Edwards, David J.; Harris, Simon R.; Cain, Amy K.; Hadfield, James; Hart, Peter J.; Thieu, Nga Tran Vu; Klemm, Elizabeth J.; Breiman, Robert F.; Watson, Conall H.; Edmunds, W. John; Kariuki, Samuel; Gordon, Melita A.; Heyderman, Robert S.; Okoro, Chinyere; Jacobs, Jan; Lunguya, Octavie; Msefula, Chisomo; Chabalgoity, Jose A.; Kama, Mike; Jenkins, Kylie; Dutta, Shanta; Marks, Florian; Campos, Josefina; Thompson, Corinne; Obaro, Stephen; MacLennan, Calman A.; Dolecek, Christiane; Keddy, Karen H.; Smith, Anthony M.; Parry, Christopher M.; Karkey, Abhilasha; Dongol, Sabina; Basnyat, Buddha; Arjyal, Amit; Mulholland, E. Kim; Campbell, James I.; Dufour, Muriel; Bandaranayake, Don; Toleafoa, Take N.; Singh, Shalini Pravin; Hatta, Mochammad; Newton, Paul N.; Dance, David; Davong, Viengmon; Onsare, Robert S.; Isaia, Lupeoletalalelei; Thwaites, Guy; Wijedoru, Lalith; Crump, John A.; De Pinna, Elizabeth; Nair, Satheesh; Nilles, Eric J.; Thanh, Duy Pham; Turner, Paul; Soeng, Sona; Valcanis, Mary; Powling, Joan; Dimovski, Karolina; Hogg, Geoff; Farrar, Jeremy; Mather, Alison E.; Amos, Ben

2016-01-01

The population of Salmonella enterica serovar Typhi (S. Typhi), the causative agent of typhoid fever, exhibits limited DNA sequence variation, which complicates efforts to rationally discriminate individual isolates. Here we utilize data from whole-genome sequences (WGS) of nearly 2,000 isolates sourced from over 60 countries to generate a robust genotyping scheme that is phylogenetically informative and compatible with a range of assays. These data show that, with the exception of the rapidly disseminating H58 subclade (now designated genotype 4.3.1), the global S. Typhi population is highly structured and includes dozens of subclades that display geographical restriction. The genotyping approach presented here can be used to interrogate local S. Typhi populations and help identify recent introductions of S. Typhi into new or previously endemic locations, providing information on their likely geographical source. This approach can be used to classify clinical isolates and provides a universal framework for further experimental investigations. PMID:27703135

The Vi Capsular Polysaccharide Enables Salmonella enterica Serovar Typhi to Evade Microbe-Guided Neutrophil Chemotaxis

PubMed Central

Wangdi, Tamding; Lee, Cheng-Yuk; Spees, Alanna M.; Yu, Chenzhou; Kingsbury, Dawn D.; Winter, Sebastian E.; Hastey, Christine J.; Wilson, R. Paul

2014-01-01

Salmonella enterica serovar Typhi (S. Typhi) causes typhoid fever, a disseminated infection, while the closely related pathogen S. enterica serovar Typhimurium (S. Typhimurium) is associated with a localized gastroenteritis in humans. Here we investigated whether both pathogens differ in the chemotactic response they induce in neutrophils using a single-cell experimental approach. Surprisingly, neutrophils extended chemotactic pseudopodia toward Escherichia coli and S. Typhimurium, but not toward S. Typhi. Bacterial-guided chemotaxis was dependent on the presence of complement component 5a (C5a) and C5a receptor (C5aR). Deletion of S. Typhi capsule biosynthesis genes markedly enhanced the chemotactic response of neutrophils in vitro. Furthermore, deletion of capsule biosynthesis genes heightened the association of S. Typhi with neutrophils in vivo through a C5aR-dependent mechanism. Collectively, these data suggest that expression of the virulence-associated (Vi) capsular polysaccharide of S. Typhi obstructs bacterial-guided neutrophil chemotaxis. PMID:25101794

Epidemiology, clinical presentation, and patterns of drug resistance of Salmonella Typhi in Karachi, Pakistan.

PubMed

Khan, M Imran; Soofi, Sajid Bashir; Ochiai, R Leon; Khan, Mohammad Jawed; Sahito, Shah Muhammad; Habib, Mohammad Atif; Puri, Mahesh K; Von Seidlein, Lorenz; Park, Jin Kyung; You, Young Ae; Ali, Mohammad; Nizami, S Qamarudding; Acosta, Camilo J; Sack, R Bradley; Clemens, John D; Bhutta, Zulfiqar A

2012-10-19

Enteric fever remains a major public health problem in Asia. Planning appropriate preventive measures such as immunization requires a clear understanding of disease burden. We conducted a community-based surveillance for Salmonella Typhi infection in children in Karachi, Pakistan. A de jure household census was conducted at baseline in the study setting to enumerate all individuals. A health-care facility-based passive surveillance system was used to capture episodes of fever lasting three or more 3 days in children 2 to 16 years old. A total of 7,401 blood samples were collected for microbiological confirmation, out of which 189 S. Typhi and 32 S. Paratyphi A isolates were identified with estimated annual incidences of 451/100,000 (95% CI: 446 - 457) and 76/100,000 (95% CI: 74 - 78) respectively. At the time of presentation, after adjusting for age, there was an association between the duration of fever and temperature at presentation, and being infected with multidrug-resistant S. Typhi. Of 189 isolates 83 were found to be resistant to first-line antimicrobial therapy. There was no statistically significant difference in clinical presentation of blood culture sensitive and resistant S. Typhi isolates. Incidence of S. Typhi in children is high in urban squatter settlements of Karachi, Pakistan. Findings from this study identified duration of fever and temperature at the time of presentation as important symptoms associated with blood culture-confirmed typhoid fever. Preventive strategies such as immunization and improvements in water and sanitation conditions should be the focus of typhoid control in urban settlements of Pakistan.

The prevalence and clinical features of multi-drug resistant Salmonella typhi infections in Baluchistan, Pakistan.

PubMed

Mirza, S H; Beeching, N J; Hart, C A

1995-10-01

Between January and July 1994, a prospective study of bacteraemia in 692 patients with fever without localizing signs was undertaken at the Quetta Military Hospital in Baluchistan, Pakistan. Salmonella spp. were isolated from 76 (11%) of the patients; 62 had S. typhi and 14 had S. paratyphi A. Significantly more isolations of S. typhi were made in the hot dry months of May and June than in the earlier months. Although multi-drug resistance (to chloramphenicol ampicillin and cotrimoxazole) was detected in 43 (69%) of the S. typhi isolates, it was not found in any of the S. paratyphi A. Defervescence of patients with chloramphenicol-sensitive S. typhi took 7-10 days of chloramphenicol therapy. In contrast, most (91%) of the patients infected with multi-drug resistant S. typhi who were treated with fluoroquinolones achieved defervescence in 1-3 days; the remainder took 4-6 days.

Vaccination of active component US military personnel against Salmonella Typhi.

PubMed

Porter, Chad K; Sorrell, Tia; Mitra, Indrani; Riddle, Mark S

2017-03-27

Vaccination against Salmonella Typhi is one of the leading public health interventions reducing the risk of typhoid fever. There are two available licensed vaccines, Vivotif, oral live-attenuated, and Typhim Vi, intramuscular Vi capsular polysaccharide. The US military is a high risk travel population commonly vaccinated for S. Typhi. We describe the use of S. Typhi vaccination in this population and the acute reactogenicity profile of these vaccines. Data were obtained from the Defense Medical Surveillance System and vaccination identified between 1998 and 2011 from vaccination codes. Clinical outcomes were assessed for four weeks post vaccination. Adverse event rates and odds ratios were estimated across the two vaccine types. A total of 1.9million predominately male military personnel received 3.6 million S. Typhi vaccinations with 94.3% of vaccinees receiving the Vi capsule vaccine though variability in the vaccine administered was observed. Receipt of other vaccinations in the 6months surrounding the S. Typhi vaccine was common. Rates of nausea (195 per 100,000 vaccinations), headache (13 per 100,000 vaccinations) and fever (40 per 100,000 vaccinations) were significantly higher following Vi capsule vaccination compared to receipt of Vivotif (130, 2, 10 per 100,000 vaccinations, respectively). In contrast the rates of rash and non-infectious diarrhea (186 and 426 per 100,000 vaccinations, respectively) were increased in those receiving Vivotif compared to the Vi capsule vaccine. The US military is a major consumer of S. Typhi vaccines. The parenterally administered vaccine appears to be more amenable, though we were limited in our ability to assess the reasons for its higher usage. While we observed a higher rate of several adverse events in subjects receiving the intramuscular vaccination, the overall rate of these events was low. Future studies assessing more long-term health outcomes are warranted. Published by Elsevier Ltd.

Formation and resuscitation of viable but nonculturable Salmonella typhi.

PubMed

Zeng, Bin; Zhao, Guozhong; Cao, Xiaohong; Yang, Zhen; Wang, Chunling; Hou, Lihua

2013-01-01

Salmonella typhi is a pathogen that causes the human disease of typhoid fever. The aim of this study was to investigate the viable but nonculturable (VBNC) state of S. typhi. Some samples were stimulated at 4°C or -20°C, while others were induced by different concentrations of CuSO4. Total cell counts remained constant throughout several days by acridine orange direct counting; however, plate counts declined to undetectable levels within 48 hours by plate counting at -20°C. The direct viable counts remained fairly constant at this level by direct viable counting. Carbon and nitrogen materials slowly decreased which indicated that a large population of cells existed in the VBNC state and entered the VBNC state in response to exposure to 0.01 or 0.015 mmol/L CuSO4 for more than 14 or 12 days, respectively. Adding 3% Tween 20 or 1% catalase enabled cells to become culturable again, with resuscitation times of 48 h and 24 h, respectively. The atomic force microscope results showed that cells gradually changed in shape from short rods to coccoids, and decreased in size when they entered the VBNC state. Further animal experiments suggested that resuscitated cells might regain pathogenicity.

Dynamic Modularity of Host Protein Interaction Networks in Salmonella Typhi Infection

PubMed Central

Dhal, Paltu Kumar; Barman, Ranjan Kumar; Saha, Sudipto; Das, Santasabuj

2014-01-01

Background Salmonella Typhi is a human-restricted pathogen, which causes typhoid fever and remains a global health problem in the developing countries. Although previously reported host expression datasets had identified putative biomarkers and therapeutic targets of typhoid fever, the underlying molecular mechanism of pathogenesis remains incompletely understood. Methods We used five gene expression datasets of human peripheral blood from patients suffering from S. Typhi or other bacteremic infections or non-infectious disease like leukemia. The expression datasets were merged into human protein interaction network (PIN) and the expression correlation between the hubs and their interacting proteins was measured by calculating Pearson Correlation Coefficient (PCC) values. The differences in the average PCC for each hub between the disease states and their respective controls were calculated for studied datasets. The individual hubs and their interactors with expression, PCC and average PCC values were treated as dynamic subnetworks. The hubs that showed unique trends of alterations specific to S. Typhi infection were identified. Results We identified S. Typhi infection-specific dynamic subnetworks of the host, which involve 81 hubs and 1343 interactions. The major enriched GO biological process terms in the identified subnetworks were regulation of apoptosis and biological adhesions, while the enriched pathways include cytokine signalling in the immune system and downstream TCR signalling. The dynamic nature of the hubs CCR1, IRS2 and PRKCA with their interactors was studied in detail. The difference in the dynamics of the subnetworks specific to S. Typhi infection suggests a potential molecular model of typhoid fever. Conclusions Hubs and their interactors of the S. Typhi infection-specific dynamic subnetworks carrying distinct PCC values compared with the non-typhoid and other disease conditions reveal new insight into the pathogenesis of S. Typhi. PMID:25144185

Molecular diagnosis of Salmonella typhi and its virulence in suspected typhoid blood samples through nested multiplex PCR.

PubMed

Prabagaran, Solai Ramatchandirane; Kalaiselvi, Vellingiri; Chandramouleeswaran, Naganathan; Deepthi, Krishnan Nair Geetha; Brahmadathan, Kootallur Narayanan; Mani, Mariappa

2017-08-01

A nested multiplex polymerase chain reaction (PCR) based diagnosis was developed for the detection of virulent Salmonella typhi in the blood specimens from patients suspected for typhoid fever. After the Widal test, two pairs of primers were used for the detection of flagellin gene (fliC) of S. typhi. Among them, those positive for fliC alone were subjected to identification of genes in Via B operon of Salmonella Pathogenesity Island (SPI-7) where four primer pairs were used to detect tviA and tviB genes. Among 250 blood samples tested, 115 were positive by fliC PCR; 22 of these were negative for tviA and tviB. Hence, the method described here can be used to diagnose the incidence of Vi-negative serovar typhi especially in endemic regions where the Vi vaccine is administered. Copyright © 2017 Elsevier B.V. All rights reserved.

Genetic Fine Structure of a Salmonella enterica Serovar Typhi Strain Associated with the 2005 Outbreak of Typhoid Fever in Kelantan, Malaysia

PubMed Central

Baddam, Ramani; Kumar, Narender; Thong, Kwai-Lin; Ngoi, Soo-Tein; Teh, Cindy Shuan Ju; Yap, Kien-Pong; Chai, Lay-Ching; Avasthi, Tiruvayipati Suma

2012-01-01

Among enteric pathogens, Salmonella enterica serovar Typhi is responsible for the largest number of food-borne outbreaks and fatalities. The ability of the pathogen to cause systemic infection for extended durations leads to a high cost of disease control. Chronic carriers play important roles in the evolution of Salmonella Typhi; therefore, identification and in-depth characterization of isolates from clinical cases and carriers, especially those from zones of endemicity where the pathogen has not been extensively studied, are necessary. Here, we describe the genome sequence of the highly virulent Salmonella Typhi strain BL196/05 isolated during the outbreak of typhoid in Kelantan, Malaysia, in 2005. The whole-genome sequence and comparative genomics of this strain should enable us to understand the virulence mechanisms and evolutionary dynamics of this pathogen in Malaysia and elsewhere. PMID:22689247

A study of Salmonella typhi isolated in Suez Canal area. Biotyping, phage typing and colicinogenic property.

PubMed

Shoeb, S; Khalifa, I; el Daly, O; Heiba, A; Farmer, J; Brenner, F; el Batawi, Y

1989-01-01

In this work a total of 82 strains of Salmonella typhi were isolated from Egyptian patients diagnosed as quiry enteric fever. These cases were from Ismalia, Suez and port Said Areas. The strains fell in 16 phage types. Phage types N, 40, E1, and degraded Vi were the commonest phage type in Ismailia, while phage types degraded Vi and C1 were the commonest in Port Said. Phage types Di-N, degraded Vi, A and C1 were the commonest in Suez. Chemotyping of Salmonella typhi showed that the majority of the strains belonged to chemotype I (82%), and the rest belonged to chemotype II (18%). Colicin production was negative and all the strains were susceptible to the currently used antibiotics.

Identification of Five Novel Salmonella Typhi-Specific Genes as Markers for Diagnosis of Typhoid Fever Using Single-Gene Target PCR Assays.

PubMed

Goay, Yuan Xin; Chin, Kai Ling; Tan, Clarissa Ling Ling; Yeoh, Chiann Ying; Ja'afar, Ja'afar Nuhu; Zaidah, Abdul Rahman; Chinni, Suresh Venkata; Phua, Kia Kien

2016-01-01

Salmonella Typhi ( S . Typhi) causes typhoid fever which is a disease characterised by high mortality and morbidity worldwide. In order to curtail the transmission of this highly infectious disease, identification of new markers that can detect the pathogen is needed for development of sensitive and specific diagnostic tests. In this study, genomic comparison of S . Typhi with other enteric pathogens was performed, and 6 S . Typhi genes, that is, STY0201, STY0307, STY0322, STY0326, STY2020, and STY2021, were found to be specific in silico . Six PCR assays each targeting a unique gene were developed to test the specificity of these genes in vitro . The diagnostic sensitivities and specificities of each assay were determined using 39 S . Typhi, 62 non-Typhi Salmonella , and 10 non- Salmonella clinical isolates. The results showed that 5 of these genes, that is, STY0307, STY0322, STY0326, STY2020, and STY2021, demonstrated 100% sensitivity (39/39) and 100% specificity (0/72). The detection limit of the 5 PCR assays was 32 pg for STY0322, 6.4 pg for STY0326, STY2020, and STY2021, and 1.28 pg for STY0307. In conclusion, 5 PCR assays using STY0307, STY0322, STY0326, STY2020, and STY2021 were developed and found to be highly specific at single-gene target resolution for diagnosis of typhoid fever.

Characterization of Anti-Salmonella enterica Serotype Typhi Antibody Responses in Bacteremic Bangladeshi Patients Using Immuno-affinity Proteomic-based Technology (IPT)

USDA-ARS?s Scientific Manuscript database

Salmonella enterica serotype Typhi (S. Typhi) is the cause of typhoid fever and a human-restricted pathogen. Currently available typhoid vaccines provide only 50-75% protection for 2-5 years, and available diagnostic assays to identify individuals with typhoid fever lack both sensitivity and specifi...

Oral Challenge with Wild-Type Salmonella Typhi Induces Distinct Changes in B Cell Subsets in Individuals Who Develop Typhoid Disease.

PubMed

Toapanta, Franklin R; Bernal, Paula J; Fresnay, Stephanie; Magder, Laurence S; Darton, Thomas C; Jones, Claire; Waddington, Claire S; Blohmke, Christoph J; Angus, Brian; Levine, Myron M; Pollard, Andrew J; Sztein, Marcelo B

2016-06-01

A novel human oral challenge model with wild-type Salmonella Typhi (S. Typhi) was recently established by the Oxford Vaccine Group. In this model, 104 CFU of Salmonella resulted in 65% of participants developing typhoid fever (referred here as typhoid diagnosis -TD-) 6-9 days post-challenge. TD was diagnosed in participants meeting clinical (oral temperature ≥38°C for ≥12h) and/or microbiological (S. Typhi bacteremia) endpoints. Changes in B cell subpopulations following S. Typhi challenge remain undefined. To address this issue, a subset of volunteers (6 TD and 4 who did not develop TD -NoTD-) was evaluated. Notable changes included reduction in the frequency of B cells (cells/ml) of TD volunteers during disease days and increase in plasmablasts (PB) during the recovery phase (>day 14). Additionally, a portion of PB of TD volunteers showed a significant increase in activation (CD40, CD21) and gut homing (integrin α4β7) molecules. Furthermore, all BM subsets of TD volunteers showed changes induced by S. Typhi infections such as a decrease in CD21 in switched memory (Sm) CD27+ and Sm CD27- cells as well as upregulation of CD40 in unswitched memory (Um) and Naïve cells. Furthermore, changes in the signaling profile of some BM subsets were identified after S. Typhi-LPS stimulation around time of disease. Notably, naïve cells of TD (compared to NoTD) volunteers showed a higher percentage of cells phosphorylating Akt suggesting enhanced survival of these cells. Interestingly, most these changes were temporally associated with disease onset. This is the first study to describe differences in B cell subsets directly related to clinical outcome following oral challenge with wild-type S. Typhi in humans.

Multidrug-Resistant Salmonella enterica Serotype Typhi, Gulf of Guinea Region, Africa

PubMed Central

Baltazar, Murielle; Ngandjio, Antoinette; Holt, Kathryn Elizabeth; Lepillet, Elodie; Pardos de la Gandara, Maria; Collard, Jean-Marc; Bercion, Raymond; Nzouankeu, Ariane; Le Hello, Simon; Dougan, Gordon; Fonkoua, Marie-Christine

2015-01-01

We identified 3 lineages among multidrug-resistant (MDR) Salmonella enterica serotype Typhi isolates in the Gulf of Guinea region in Africa during the 2000s. However, the MDR H58 haplotype, which predominates in southern Asia and Kenya, was not identified. MDR quinolone-susceptible isolates contained a 190-kb incHI1 pST2 plasmid or a 50-kb incN pST3 plasmid. PMID:25811307

An Outbreak of Food-Borne Typhoid Fever Due to Salmonella enterica Serotype Typhi in Japan Reported for the First Time in 16 Years

PubMed Central

Kobayashi, Tetsuro; Kutsuna, Satoshi; Hayakawa, Kayoko; Kato, Yasuyuki; Ohmagari, Norio; Uryu, Hideko; Yamada, Ritsuko; Kashiwa, Naoyuki; Nei, Takahito; Ehara, Akihito; Takei, Reiko; Mori, Nobuaki; Yamada, Yasuhiro; Hayasaka, Tomomi; Kagawa, Narito; Sugawara, Momoko; Suzaki, Ai; Takahashi, Yuno; Nishiyama, Hiroyuki; Morita, Masatomo; Izumiya, Hidemasa; Ohnishi, Makoto

2016-01-01

For the first time in 16 years, a food-borne outbreak of typhoid fever due to Salmonella enterica serotype Typhi was reported in Japan. Seven patients consumed food in an Indian buffet at a restaurant in the center of Tokyo, while one was a Nepali chef in the restaurant, an asymptomatic carrier and the implicated source of this outbreak. The multiple-locus variable-number tandem repeat analysis showed 100% consistency in the genomic sequence for five of the eight cases. PMID:26621565

An Inducible and Secreted Eukaryote-Like Serine/Threonine Kinase of Salmonella enterica Serovar Typhi Promotes Intracellular Survival and Pathogenesis

PubMed Central

Theeya, Nagaraja; Ta, Atri; Das, Sayan; Mandal, Rahul S.; Chakrabarti, Oishee; Chakrabarti, Saikat; Ghosh, Amar N.

2014-01-01

Eukaryote-like serine/threonine kinases (eSTKs) constitute an important family of bacterial virulence factors. Genome analysis had predicted putative eSTKs in Salmonella enterica serovar Typhi, although their functional characterization and the elucidation of their role in pathogenesis are still awaited. We show here that the primary sequence and secondary structure of the t4519 locus of Salmonella Typhi Ty2 have all the signatures of eukaryotic superfamily kinases. t4519 encodes a ∼39-kDa protein (T4519), which shows serine/threonine kinase activities in vitro. Recombinant T4519 (rT4519) is autophosphorylated and phosphorylates the universal substrate myelin basic protein. Infection of macrophages results in decreased viability of the mutant (Ty2Δt4519) strain, which is reversed by gene complementation. Moreover, reactive oxygen species produced by the macrophages signal to the bacteria to induce T4519, which is translocated to the host cell cytoplasm. That T4519 may target a host substrate(s) is further supported by the activation of host cellular signaling pathways and the induction of cytokines/chemokines. Finally, the role of T4519 in the pathogenesis of Salmonella Typhi is underscored by the significantly decreased mortality of mice infected with the Ty2Δt4519 strain and the fact that the competitive index of this strain for causing systemic infection is 0.25% that of the wild-type strain. This study characterizes the first eSTK of Salmonella Typhi and demonstrates its role in promoting phagosomal survival of the bacteria within macrophages, which is a key determinant of pathogenesis. This, to the best of our knowledge, is the first study to describe the essential role of eSTKs in the in vivo pathogenesis of Salmonella spp. PMID:25404028

Lack of efflux mediated quinolone resistance in Salmonella enterica serovars Typhi and Paratyphi A

PubMed Central

Baucheron, Sylvie; Monchaux, Isabelle; Le Hello, Simon; Weill, François-Xavier; Cloeckaert, Axel

2014-01-01

Salmonella enterica serovars Typhi and Paratyphi A isolates from human patients in France displaying different levels of resistance to quinolones or fluoroquinolones were studied for resistance mechanisms to these antimicrobial agents. All resistant isolates carried either single or multiple target gene mutations (i.e., in gyrA, gyrB, or parC) correlating with the resistance levels observed. Active efflux, through upregulation of multipartite efflux systems, has also been previously reported as contributing mechanism for other serovars. Therefore, we investigated also the occurrence of non-target gene mutations in regulatory regions affecting efflux pump expression. However, no mutation was detected in these regions in both Typhi and Paratyphi isolates of this study. Besides, no overexpression of the major efflux systems was observed for these isolates. Nevertheless, a large deletion of 2334 bp was identified in the acrS-acrE region of all S. Typhi strains but which did not affect the resistance phenotype. As being specific to S. Typhi, this deletion could be used for specific molecular detection purposes. In conclusion, the different levels of quinolone or FQ resistance in both S. Typhi and S. Paratyphi A seem to rely only on target modifications. PMID:24478769

Epidemic Typhoid in Vietnam: Molecular Typing of Multiple-Antibiotic-Resistant Salmonella enterica Serotype Typhi from Four Outbreaks

PubMed Central

Connerton, Phillippa; Wain, John; Hien, Tran T.; Ali, Tahir; Parry, Christopher; Chinh, Nguyen T.; Vinh, Ha; Ho, Vo A.; Diep, To S.; Day, Nicholas P. J.; White, Nicholas J.; Dougan, Gordon; Farrar, Jeremy J.

2000-01-01

Multidrug-resistant Salmonella enterica serotype Typhi isolates from four outbreaks of typhoid fever in southern Vietnam between 1993 and 1997 were compared. Pulsed-field gel electrophoresis, bacteriophage and plasmid typing, and antibiotic susceptibilities showed that independent outbreaks of multidrug-resistant typhoid fever in southern Vietnam are caused by single bacterial strains. However, different outbreaks do not derive from the clonal expansion of a single multidrug-resistant serotype Typhi strain. PMID:10655411

[Severe cases of Salmonella non typhi infections on sickle cell patients in Réunion Island].

PubMed

Vandroux, D; Jabot, J; Angue, M; Belcour, D; Galliot, R; Allyn, J; Gaüzère, B-A

2014-12-01

We report two cases of septic shocks due to Salmonella non typhi infection on sickle cell patients admitted to an intensive care unit. Such patients should enforce food hygiene measures, especially under tropical settings, to avoid potentially deadly severe infections.

Mix-infection of S. Typhi and ParaTyphi A in Typhoid Fever and Chronic Typhoid Carriers: A Nested PCR Based Study in North India

PubMed Central

Pratap, Chandra Bhan; Kumar, Gopal; Patel, Saurabh Kumar; Shukla, Vijay K; Kumar, Kailash; Singh, Tej Bali

2014-01-01

Introduction: Enteric fever is a systemic disease caused by Salmonella organism such as serotypes Typhi and ParaTyphi A, B, C. Salmonella ParaTyphi A contributes more than 50% of all the enteric fever cases and it has recently been projected as an emerging pathogen. Materials and Methods: The present study was aimed to detect Salmonella Typhi and ParaTyphi A in urine, blood and stool specimens collected from cases of enteric fever (110), chronic typhoid carriers (46) and healthy controls (75) to explore the possibility of mixed infection by nested PCR. A new nested PCR primer was designed targeting putative fimbrial protein (stkG) gene which is one of the fimbrial gene families to Salmonella ParaTyphi A and for S. Typhi already reported primers targeting flagellin (fliC) gene. Results: Large volume of urine specimens (15 ml) was found to be the best for detection of Salmonella serotypes. The urine sample was found to have mixed-infection by both the serotypes in 40.9% of the cases but lower in blood (27.3%) and stool (13.6%). Conclusion: The present study concludes that occurrence of mixed infection may be quite frequent in typhoid and chronic typhoid carriers’ individuals, although the reported recent rise in ParaTyphi A incidence may not be real. PMID:25584217

Inhibition of Salmonella typhi growth using extremely low frequency electromagnetic (ELF-EM) waves at resonance frequency.

PubMed

Fadel, M A; Mohamed, S A; Abdelbacki, A M; El-Sharkawy, A H

2014-08-01

Typhoid is a serious disease difficult to be treated with conventional drugs. The aim of this study was to demonstrate a new method for the control of Salmonella typhi growth, through the interference with the bioelectric signals generated from the microbe during cell division by extremely low frequency electromagnetic waves (ELF-EMW-ELF-EM) at resonance frequency. Isolated Salmonella typhi was subjected to square amplitude modulated waves (QAMW) with different modulation frequencies from two generators with constant carrier frequency of 10 MHz, amplitude of 10 Vpp, modulating depth ± 2 Vpp and constant field strength of 200 V m(-1) at 37°C. Both the control and exposed samples were incubated at the same conditions during the experiment. The results showed that there was highly significant inhibition effect for Salm. typhi exposed to 0·8 Hz QAMW for a single exposure for 75 min. Dielectric relaxation, TEM and DNA results indicated highly significant changes in the molecular structure of the DNA and cellular membrane resulting from the exposure to the inhibiting EM waves. It was concluded that finding out the inhibiting resonance frequency of ELF-EM waves that deteriorates Salm. typhi growth will be promising method for the treatment of Salm. typhi infection either in vivo or in vitro. This new non-invasive technique for treatment of bacterial infections is of considerable interest for the use in medical and biotechnological applications. © 2014 The Society for Applied Microbiology.

Comparison of genome degradation in Paratyphi A and Typhi, human-restricted serovars of Salmonella enterica that cause typhoid.

PubMed

McClelland, Michael; Sanderson, Kenneth E; Clifton, Sandra W; Latreille, Phil; Porwollik, Steffen; Sabo, Aniko; Meyer, Rekha; Bieri, Tamberlyn; Ozersky, Phil; McLellan, Michael; Harkins, C Richard; Wang, Chunyan; Nguyen, Christine; Berghoff, Amy; Elliott, Glendoria; Kohlberg, Sara; Strong, Cindy; Du, Feiyu; Carter, Jason; Kremizki, Colin; Layman, Dan; Leonard, Shawn; Sun, Hui; Fulton, Lucinda; Nash, William; Miner, Tracie; Minx, Patrick; Delehaunty, Kim; Fronick, Catrina; Magrini, Vincent; Nhan, Michael; Warren, Wesley; Florea, Liliana; Spieth, John; Wilson, Richard K

2004-12-01

Salmonella enterica serovars often have a broad host range, and some cause both gastrointestinal and systemic disease. But the serovars Paratyphi A and Typhi are restricted to humans and cause only systemic disease. It has been estimated that Typhi arose in the last few thousand years. The sequence and microarray analysis of the Paratyphi A genome indicates that it is similar to the Typhi genome but suggests that it has a more recent evolutionary origin. Both genomes have independently accumulated many pseudogenes among their approximately 4,400 protein coding sequences: 173 in Paratyphi A and approximately 210 in Typhi. The recent convergence of these two similar genomes on a similar phenotype is subtly reflected in their genotypes: only 30 genes are degraded in both serovars. Nevertheless, these 30 genes include three known to be important in gastroenteritis, which does not occur in these serovars, and four for Salmonella-translocated effectors, which are normally secreted into host cells to subvert host functions. Loss of function also occurs by mutation in different genes in the same pathway (e.g., in chemotaxis and in the production of fimbriae).

Characterization of Anti-Salmonella enterica Serotype Typhi Antibody Responses in Bacteremic Bangladeshi Patients by an Immuno-affinity Proteomic-based Technology (IPT)

USDA-ARS?s Scientific Manuscript database

Salmonella enterica serotype Typhi (S. Typhi) is the cause of typhoid fever and a human-restricted pathogen. Currently available typhoid vaccines provide only 50-75% protection for 2-5 years, and available diagnostic assays to identify individuals with typhoid fever lack both sensitivity and specif...

In vivo expression of Salmonella enterica serotype Typhi genes in the blood of patients with typhoid fever in Bangladesh.

PubMed

Sheikh, Alaullah; Charles, Richelle C; Sharmeen, Nusrat; Rollins, Sean M; Harris, Jason B; Bhuiyan, Md Saruar; Arifuzzaman, Mohammad; Khanam, Farhana; Bukka, Archana; Kalsy, Anuj; Porwollik, Steffen; Leung, Daniel T; Brooks, W Abdullah; LaRocque, Regina C; Hohmann, Elizabeth L; Cravioto, Alejandro; Logvinenko, Tanya; Calderwood, Stephen B; McClelland, Michael; Graham, James E; Qadri, Firdausi; Ryan, Edward T

2011-12-01

Salmonella enterica serotype Typhi is the cause of typhoid fever. It is a human-restricted pathogen, and few data exist on S. Typhi gene expression in humans. We applied an RNA capture and amplification technique, Selective Capture of Transcribed Sequences (SCOTS), and microarray hybridization to identify S. Typhi transcripts expressed in the blood of five humans infected with S. Typhi in Bangladesh. In total, we detected the expression of mRNAs for 2,046 S. Typhi genes (44% of the S. Typhi genome) in human blood; expression of 912 genes was detected in all 5 patients, and expression of 1,100 genes was detected in 4 or more patients. Identified transcripts were associated with the virulence-associated PhoP regulon, Salmonella pathogenicity islands, the use of alternative carbon and energy sources, synthesis and transport of iron, thiamine, and biotin, and resistance to antimicrobial peptides and oxidative stress. The most highly represented group were genes currently annotated as encoding proteins designated as hypothetical, unknown, or unclassified. Of the 2,046 detected transcripts, 1,320 (29% of the S. Typhi genome) had significantly different levels of detection in human blood compared to in vitro cultures; detection of 141 transcripts was significantly different in all 5 patients, and detection of 331 transcripts varied in at least 4 patients. These mRNAs encode proteins of unknown function, those involved in energy metabolism, transport and binding, cell envelope, cellular processes, and pathogenesis. We confirmed increased expression of a subset of identified mRNAs by quantitative-PCR. We report the first characterization of bacterial transcriptional profiles in the blood of patients with typhoid fever. S. Typhi is an important global pathogen whose restricted host range has greatly inhibited laboratory studies. Our results suggest that S. Typhi uses a largely uncharacterized genetic repertoire to survive within cells and utilize alternate energy sources

PCR Method To Identify Salmonella enterica Serovars Typhi, Paratyphi A, and Paratyphi B among Salmonella Isolates from the Blood of Patients with Clinical Enteric Fever▿

PubMed Central

Levy, Haim; Diallo, Souleymane; Tennant, Sharon M.; Livio, Sofie; Sow, Samba O.; Tapia, Milagritos; Fields, Patricia I.; Mikoleit, Matthew; Tamboura, Boubou; Kotloff, Karen L.; Lagos, Rosanna; Nataro, James P.; Galen, James E.; Levine, Myron M.

2008-01-01

PCR methodology was developed to identify Salmonella enterica serovars Typhi, Paratyphi A, and Paratyphi B. One multiplex PCR identifies serogroup D, A, and B and Vi-positive strains; another confirms flagellar antigen “d,” “a,” or “b.” Blinded testing of 664 Malian and Chilean Salmonella blood isolates demonstrated 100% sensitivity and specificity. PMID:18367574

Vi Capsular Polysaccharide Produced by Recombinant Salmonella enterica Serovar Paratyphi A Confers Immunoprotection against Infection by Salmonella enterica Serovar Typhi

PubMed Central

Xiong, Kun; Zhu, Chunyue; Chen, Zhijin; Zheng, Chunping; Tan, Yong; Rao, Xiancai; Cong, Yanguang

2017-01-01

Enteric fever is predominantly caused by Salmonella enterica serovar Typhi and Salmonella enterica serovar Paratyphi A, and accounts for an annual global incidence of 26.9 millions. In recent years, the rate of S. Paratyphi A infection has progressively increased. Currently licensed vaccines for typhoid fever, live Ty21a vaccine, Vi subunit vaccine, and Vi-conjugate vaccine, confer inadequate cross immunoprotection against enteric fever caused by S. Paratyphi A. Therefore, development of bivalent vaccines against enteric fever is urgently required. The immunogenic Vi capsular polysaccharide is characteristically produced in S. Typhi, but it is absent in S. Paratyphi A. We propose that engineering synthesis of Vi in S. Paratyphi A live-attenuated vaccine may expand its protection range to cover S. Typhi. In this study, we cloned the viaB locus, which contains 10 genes responsible for Vi biosynthesis, and integrated into the chromosome of S. Paratyphi A CMCC 50093. Two virulence loci, htrA and phoPQ, were subsequently deleted to achieve a Vi-producing attenuated vaccine candidate. Our data showed that, despite more than 200 passages, the viaB locus was stably maintained in the chromosome of S. Paratyphi A and produced the Vi polysaccharide. Nasal immunization of the vaccine candidate stimulated high levels of Vi-specific and S. Paratyphi A-specific antibodies in mice sera as well as total sIgA in intestinal contents, and showed significant protection against wild-type challenge of S. Paratyphi A or S. Typhi. Our study show that the Vi-producing attenuated S. Paratyphi A is a promising bivalent vaccine candidate for the prevention of enteric fever. PMID:28484685

CTX-M-producing non-Typhi Salmonella spp. isolated from humans, United States.

PubMed

Sjölund-Karlsson, Maria; Howie, Rebecca; Krueger, Amy; Rickert, Regan; Pecic, Gary; Lupoli, Kathryn; Folster, Jason P; Whichard, Jean M

2011-01-01

CTX-M-type beta-lactamases are increasing among US Enterobacteriaceae isolates. Of 2,165 non-Typhi Salmonella isolates submitted in 2007 to the National Antimicrobial Resistance Monitoring System, 100 (4.6%) displayed elevated MICs (≥2 mg/L) of ceftriaxone or ceftiofur. Three isolates (serotypes Typhimurium, Concord, and I 4,5,12:i:-) contained bla(CTX-M-5), bla(CTX-M-15), and bla(CTX-M-55/57), respectively.

CTX-M–producing Non-Typhi Salmonella spp. Isolated from Humans, United States

PubMed Central

Howie, Rebecca; Krueger, Amy; Rickert, Regan; Pecic, Gary; Lupoli, Kathryn; Folster, Jason P.; Whichard, Jean M.

2011-01-01

CTX-M–type β-lactamases are increasing among US Enterobacteriaceae isolates. Of 2,165 non-Typhi Salmonella isolates submitted in 2007 to the National Antimicrobial Resistance Monitoring System, 100 (4.6%) displayed elevated MICs (>2 mg/L) of ceftriaxone or ceftiofur. Three isolates (serotypes Typhimurium, Concord, and I 4,5,12:i:–) contained blaCTX-M-5, blaCTX-M-15, and blaCTX-M-55/57, respectively. PMID:21192864

Chromosomal Rearrangements in Salmonella enterica Serotype Typhi Affecting Molecular Typing in Outbreak Investigations

PubMed Central

Echeita, M. A.; Usera, M. A.

1998-01-01

Salmonella enterica serotype Typhi strains belonging to eight different outbreaks of typhoid fever that occurred in Spain between 1989 and 1994 were analyzed by ribotyping and pulsed-field gel electrophoresis. For three outbreaks, two different patterns were detected for each outbreak. The partial digestion analysis by the intron-encoded endonuclease I-CeuI of the two different strains from each outbreak provided an excellent tool for examining the organization of the genomes of epidemiologically related strains. S. enterica serotype Typhi seems to be more susceptible than other serotypes to genetic rearrangements produced by homologous recombinations between rrn operons; these rearrangements do not substantially alter the stability or survival of the bacterium. We conclude that genetic rearrangements can occur during the emergence of an outbreak. PMID:9650981

Functional Analysis of the Chaperone-Usher Fimbrial Gene Clusters of Salmonella enterica serovar Typhi.

PubMed

Dufresne, Karine; Saulnier-Bellemare, Julie; Daigle, France

2018-01-01

The human-specific pathogen Salmonella enterica serovar Typhi causes typhoid, a major public health issue in developing countries. Several aspects of its pathogenesis are still poorly understood. S . Typhi possesses 14 fimbrial gene clusters including 12 chaperone-usher fimbriae ( stg, sth, bcf , fim, saf , sef , sta, stb, stc, std, ste , and tcf ). These fimbriae are weakly expressed in laboratory conditions and only a few are actually characterized. In this study, expression of all S . Typhi chaperone-usher fimbriae and their potential roles in pathogenesis such as interaction with host cells, motility, or biofilm formation were assessed. All S . Typhi fimbriae were better expressed in minimal broth. Each system was overexpressed and only the fimbrial gene clusters without pseudogenes demonstrated a putative major subunits of about 17 kDa on SDS-PAGE. Six of these (Fim, Saf, Sta, Stb, Std, and Tcf) also show extracellular structure by electron microscopy. The impact of fimbrial deletion in a wild-type strain or addition of each individual fimbrial system to an S . Typhi afimbrial strain were tested for interactions with host cells, biofilm formation and motility. Several fimbriae modified bacterial interactions with human cells (THP-1 and INT-407) and biofilm formation. However, only Fim fimbriae had a deleterious effect on motility when overexpressed. Overall, chaperone-usher fimbriae seem to be an important part of the balance between the different steps (motility, adhesion, host invasion and persistence) of S . Typhi pathogenesis.

Intermediate Susceptibility to Ciprofloxacin among Salmonella enterica Serovar Typhi Isolates in Lima, Peru

PubMed Central

Lejon, Veerle; Horna, Gertrudis; Astocondor, Lizeth; Vanhoof, Raymond; Bertrand, Sophie; Jacobs, Jan

2014-01-01

Thirty-three Salmonella enterica serovar Typhi blood isolates from Lima, Peru (2008 to 2012), were fully susceptible to trimethoprim-sulfamethoxazole, chloramphenicol, ceftriaxone, and tetracycline; 8/33 (24.2%) showed intermediate susceptibility to ciprofloxacin carrying mutations in the quinolone resistance-determining region of the gyrA gene (Ser83-Phe and Asp87-Asn) and in the gyrB gene (Ser464-Phe). PMID:24371234

Vi-CRM 197 as a new conjugate vaccine against Salmonella Typhi.

PubMed

Micoli, F; Rondini, S; Pisoni, I; Proietti, D; Berti, F; Costantino, P; Rappuoli, R; Szu, S; Saul, A; Martin, L B

2011-01-17

An efficacious, low cost vaccine against typhoid fever, especially for young children, would make a major impact on disease burden in developing countries. The virulence capsular polysaccharide of Salmonella Typhi (Vi) coupled to recombinant mutant Pseudomonas aeruginosa exoprotein A (Vi-rEPA) has been shown to be highly efficacious. We investigated the use of carrier proteins included in infant vaccines, standardized the conjugation process and developed key assays required for routine lot release at production scale. Vi from a BSL1 organism, Citrobacter freundii, strain WR7011, was used as an alternative to Vi from S. Typhi. We showed that Vi conjugated to CRM(197), a non-toxic mutant of diphtheria toxin, widely used in commercial vaccines, was produced at high yield. Vi-CRM(197) proved immunogenic in animal studies, even without adjuvant. Thus, Vi-CRM(197) appears to be a suitable candidate for the development of a commercially viable, effective typhoid vaccine for developing countries. Copyright © 2010 Elsevier Ltd. All rights reserved.

Development of a one-step immunochromatographic strip test using gold nanoparticles for the rapid detection of Salmonella typhi in human serum.

PubMed

Preechakasedkit, Pattarachaya; Pinwattana, Kulwadee; Dungchai, Wijitar; Siangproh, Weena; Chaicumpa, Wanpen; Tongtawe, Pongsri; Chailapakul, Orawon

2012-01-15

An immunochromatographic strip test using gold nanoparticles was developed for the rapid detection of Salmonella typhi (S. typhi) in human serum. The strip test based on the principle of sandwich immunoassay by the specific binding of antigens from S. typhi O901 and antibody of S. typhi O901 on a nitrocellulose membrane. Antibody-gold nanoparticle conjugate was used as the label and was coated onto a glass fiber membrane, which was used as a conjugate pad. To create a test and control zone, antibody of S. typhi O901 and an anti-IgG were dotted on the nitrocellulose membrane, respectively. Positive samples were displayed as red dots at the test and control zones of the nitrocellulose membrane, while negative samples resulted in a red dot only in the control zone. The limit of detection (LOD) was found to be 1.14×10(5) cfu mL(-1), which could be visually detected by the naked eye within 15 min. This strip test provided a lower detection limit and analysis time than a dot blot immunoassay (8.88×10(6) cfu mL(-1) for LOD and 110 min for reaction time). In addition, our immunochromatographic strip test was employed to detect S. typhi in human serum effectively, with high accuracy. This strip test offers great promise for a rapid, simple and low-cost analysis of S. typhi. Copyright © 2011 Elsevier B.V. All rights reserved.

Vaccines against invasive Salmonella disease

PubMed Central

MacLennan, Calman A; Martin, Laura B; Micoli, Francesca

2014-01-01

Though primarily enteric pathogens, Salmonellae are responsible for a considerable yet under-appreciated global burden of invasive disease. In South and South-East Asia, this manifests as enteric fever caused by serovars Typhi and Paratyphi A. In sub-Saharan Africa, a similar disease burden results from invasive nontyphoidal Salmonellae, principally serovars Typhimurium and Enteritidis. The existing Ty21a live-attenuated and Vi capsular polysaccharide vaccines target S. Typhi and are not effective in young children where the burden of invasive Salmonella disease is highest. After years of lack of investment in new Salmonella vaccines, recent times have seen increased interest in the area led by emerging-market manufacturers, global health vaccine institutes and academic partners. New glycoconjugate vaccines against S. Typhi are becoming available with similar vaccines against other invasive serovars in development. With other new vaccines under investigation, including live-attenuated, protein-based and GMMA vaccines, now is an exciting time for the Salmonella vaccine field. PMID:24804797

Nalidixic Acid-Resistant Salmonella enterica Serotype Typhi Presenting as a Primary Psoas Abscess: Case Report and Review of the Literature

PubMed Central

Shakespeare, William A.; Davie, Daniel; Tonnerre, Claude; Rubin, Michael A.; Strong, Michael; Petti, Cathy A.

2005-01-01

We report an unusual case of Salmonella enterica serotype Typhi presenting as a primary psoas abscess. The isolate tested susceptible to ciprofloxacin but resistant to nalidixic acid in vitro, a pattern associated with fluoroquinolone therapeutic failures. We review the literature for serovar Typhi psoas abscess in the absence of bacteremia and discuss the importance of identifying isolates with reduced susceptibility to fluoroquinolones. PMID:15695728

Molecular typing of Salmonella enterica serovar typhi isolates from various countries in Asia by a multiplex PCR assay on variable-number tandem repeats.

PubMed

Liu, Yichun; Lee, May-Ann; Ooi, Eng-Eong; Mavis, Yeo; Tan, Ai-Ling; Quek, Hung-Hiang

2003-09-01

A multiplex PCR method incorporating primers flanking three variable-number tandem repeat (VNTR) loci (arbitrarily labeled TR1, TR2, and TR3) in the CT18 strain of Salmonella enterica serovar Typhi has been developed for molecular typing of S. enterica serovar Typhi clinical isolates from several Asian countries, including Singapore, Indonesia, India, Bangladesh, Malaysia, and Nepal. We have demonstrated that the multiplex PCR could be performed on crude cell lysates and that the VNTR banding profiles produced could be easily analyzed by visual inspection after conventional agarose gel electrophoresis. The assay was highly discriminative in identifying 49 distinct VNTR profiles among 59 individual isolates. A high level of VNTR profile heterogeneity was observed in isolates from within the same country and among countries. These VNTR profiles remained stable after the strains were passaged extensively under routine laboratory culture conditions. In contrast to the S. enterica serovar Typhi isolates, an absence of TR3 amplicons and a lack of length polymorphisms in TR1 and TR2 amplicons were observed for other S. enterica serovars, such as Salmonella enterica serovar Typhimurium, Salmonella enterica serovar Enteritidis, and Salmonella enterica serovar Paratyphi A, B, and C. DNA sequencing of the amplified VNTR regions substantiated these results, suggesting the high stability of the multiplex PCR assay. The multiplex-PCR-based VNTR profiling developed in this study provides a simple, rapid, reproducible, and high-resolution molecular tool for the epidemiological analysis of S. enterica serovar Typhi strains.

Salmonella serotypeTyphi, Shigella, and intestinal parasites among food handlers at Bahir Dar University, Ethiopia.

PubMed

Abera, Bayeh; Yitayew, Gashaw; Amare, Hiwot

2016-02-28

Food handlers play a major role in the transmission of Salmonella serotype Typhi (S. Typhi), Shigella, and intestinal parasites. This study was conducted to determine the prevalence of S. Typhi, Shigella, and intestinal parasites among food handlers at Bahir Dar University, Ethiopia. A cross-sectional study was conducted in June 2014. Stool samples from 410 food handlers were examined for bacterial pathogens and parasites. Pearson's Chi-square test, Fisher's exact test, and bivariate and multivariate logistic regression analyses were used where appropriate. The prevalence of S. Typhi, Shigella, and intestinal parasites among food handlers was 11 (2.7%), 5 (1.2%), and 53 (12.9%), respectively. Among eight intestinal parasites identified, the two most prevalent intestinal parasites were hookworm 26 (6.3%) and G. lamblia 13 (3.1%). Male food handlers were more likely to be positive than were female food handlers for S. Typhi and intestinal parasites. Furthermore, food handlers who had a history of regular medical checkups were less infected with intestinal parasites. Being male (AOR: 2.1, 95% CI: 1.2, 4.4) and not attending medical checkups (AOR: 2.9, 95% CI: 1.4, 6.1) were independent predictors of intestinal parasitic infection in food handlers. Male food handlers were reluctant to have regular parasitological examinations. There was a high proportion of food handlers with S. Typhi, Shigella, and intestinal parasites in their faces. Special emphasis should be placed on S. Typhicarriers and male food handlers. Education and periodical medical checkups for intestinal parasites and S. Typhi should be considered as intervention measures.

Non-crosslinking gold nanoprobe-LAMP for simple, colorimetric, and specific detection of Salmonella typhi

NASA Astrophysics Data System (ADS)

Bozorgmehr, Ali; Yazdanparast, Razieh; Mollasalehi, Hamidreza

2016-12-01

In this study, we developed a non-crosslinking gold nanoprobe loop-mediated isothermal amplification (LAMP) method for nanodiagnosis of bacterial typhoid fever source, Salmonella typhi. Therefore, a unique region in the S. typhi genomic DNA was targeted for LAMP amplification using a specific set of four precisely designed primers. Also, for specific colorimetric visualization of the amplicons, a thiolated oligonucleotide probe, complementary to the single-stranded loop region of the amplicons between F2 and F1C segments, was designed. The probe was bound to the surface of gold nanoparticles via covalent bonds. Increasing the salt concentration in the detection reaction medium led to aggregation of nanoprobes in the blank and the negative vessels in a time-dependent form. That was followed by a change in the surface plasmon resonance (SPR) leading to blue/black color that was observable by the naked eyes after about 5 min. Meanwhile, the original pink/red color was retained in the positive sample due to the large interparticle spaces and the stability against the ionic strength elevation which persisted for about 30 min. The whole process of DNA extraction, amplification, and detection took less than 2 h with a sensitivity of 20 CFU/ml. The developed gold nanoprobe-LAMP could serve as a simple, rapid, and cost-effective method for nanodiagnosis of S. typhi in point-of-need applications.

Endemic, Epidemic Clone of Salmonella enterica Serovar Typhi Harboring a Single Multidrug-Resistant Plasmid in Vietnam between 1995 and 2002

PubMed Central

Le, Thi Anh Hong; Lejay-Collin, Monique; Grimont, Patrick A. D.; Hoang, Thuy Long; Nguyen, Thi Vinh; Grimont, Francine; Scavizzi, Maurice R.

2004-01-01

Salmonella enterica serovar Typhi strains resistant to ampicillin, chloramphenicol, tetracyclines, streptomycin, and cotrimoxazole, isolated from sporadic cases and minor outbreaks in Vietnam between 1995 and 2002, were typed and compared. Plasmid fingerprinting, Vi bacteriophage typing, XbaI pulsed-field gel electrophoresis, and PstI ribotyping showed that endemic, epidemic multidrug-resistant typhoid fever was due, for at least 74.1% of the isolates, to one or two clones of serovar Typhi harboring a single resistance plasmid. PstI ribotyping was used as a basic technique to ensure that a serovar Typhi expansion was clonal. PMID:15243066

High-Resolution Genotyping of the Endemic Salmonella Typhi Population during a Vi (Typhoid) Vaccination Trial in Kolkata

PubMed Central

Manna, Byomkesh; Bhattacharya, Sujit K.; Bhaduri, Barnali; Pickard, Derek J.; Ochiai, R. Leon; Ali, Mohammad; Clemens, John D.; Dougan, Gordon

2012-01-01

Background Typhoid fever, caused by Salmonella enterica serovar Typhi (S. Typhi), is a major health problem especially in developing countries. Vaccines against typhoid are commonly used by travelers but less so by residents of endemic areas. Methodology We used single nucleotide polymorphism (SNP) typing to investigate the population structure of 372 S. Typhi isolated during a typhoid disease burden study and Vi vaccine trial in Kolkata, India. Approximately sixty thousand people were enrolled for fever surveillance for 19 months prior to, and 24 months following, Vi vaccination of one third of the study population (May 2003–December 2006, vaccinations given December 2004). Principal Findings A diverse S. Typhi population was detected, including 21 haplotypes. The most common were of the H58 haplogroup (69%), which included all multidrug resistant isolates (defined as resistance to chloramphenicol, ampicillin and co-trimoxazole). Quinolone resistance was particularly high among H58-G isolates (97% Nalidixic acid resistant, 30% with reduced susceptibility to ciprofloxacin). Multiple typhoid fever episodes were detected in 22 households, however household clustering was not associated with specific S. Typhi haplotypes. Conclusions Typhoid fever in Kolkata is caused by a diverse population of S. Typhi, however H58 haplotypes dominate and are associated with multidrug and quinolone resistance. Vi vaccination did not obviously impact on the haplotype population structure of the S. Typhi circulating during the study period. PMID:22303491

Development of an acid-resistant Salmonella Typhi Ty21a attenuated vector for improved oral vaccine delivery

USDA-ARS?s Scientific Manuscript database

The licensed oral, live-attenuated bacterial vaccine for typhoid fever, Salmonella Typhi strain Ty21a, has also been utilized as a vaccine delivery platform for expression of diverse foreign antigens that stimulate protection against shigellosis, anthrax, plague, or human papilloma virus. However, T...

Immunity to Salmonella typhi: considerations relevant to measurement of cellular immunity in typhoid-endemic regions.

PubMed Central

Murphy, J R; Wasserman, S S; Baqar, S; Schlesinger, L; Ferreccio, C; Lindberg, A A; Levine, M M

1989-01-01

Experiments were performed in Baltimore, Maryland and in Santiago, Chile, to determine the level of Salmonella typhi antigen-driven in vitro lymphocyte replication response which signifies specific acquired immunity to this bacterium and to determine the best method of data analysis and form of data presentation. Lymphocyte replication was measured as incorporation of 3H-thymidine into desoxyribonucleic acid. Data (ct/min/culture) were analyzed in raw form and following log transformation, by non-parametric and parametric statistical procedures. A preference was developed for log-transformed data and discriminant analysis. Discriminant analysis of log-transformed data revealed 3H-thymidine incorporation rates greater than 3,433 for particulate S. typhi, Ty2 antigen stimulated cultures signified acquired immunity at a sensitivity and specificity of 82.7; for soluble S. typhi O polysaccharide antigen-stimulated cultures, ct/min/culture values of greater than 1,237 signified immunity (sensitivity and specificity 70.5%). PMID:2702777

Amplification of ST50 gene using dry-reagent-based polymerase chain reaction for the detection of Salmonella typhi.

PubMed

Aziah, Ismail; Ravichandran, Manickam; Ismail, Asma

2007-12-01

Conventional polymerase chain reaction (PCR) testing requires many pipetting steps and has to be transported and stored in cold chain. To overcome these limitations, we designed a ready-to-use PCR test for Salmonella typhi using PCR reagents, primers against the ST50 gene of S. typhi, a built-in internal amplification control (IAC), and gel loading dye mixed and freeze-dried in a single tube. The 2-step dry-reagent-based assay was used to amplify a 1238-bp target gene and an 810-bp IAC gene from 73 BACTEC blood culture broths (33 true positives for S. typhi and 40 true negatives for non-S. typhi). The sensitivity, specificity, positive predictive value, and negative predictive value of the PCR assay were 87.9%, 100%, 100%, and 90.9%, respectively. We suggest that this rapid 2-step PCR test could be used for the rapid diagnosis of typhoid fever.

Clinically and Microbiologically Derived Azithromycin Susceptibility Breakpoints for Salmonella enterica Serovars Typhi and Paratyphi A

PubMed Central

Thieu, Nga Tran Vu; Dolecek, Christiane; Karkey, Abhilasha; Gupta, Ruchi; Turner, Paul; Dance, David; Maude, Rapeephan R.; Ha, Vinh; Tran, Chinh Nguyen; Thi, Phuong Le; Be, Bay Pham Van; Phi, La Tran Thi; Ngoc, Rang Nguyen; Ghose, Aniruddha; Dongol, Sabina; Campbell, James I.; Thanh, Duy Pham; Thanh, Tuyen Ha; Moore, Catrin E.; Sona, Soeng; Gaind, Rajni; Deb, Monorama; Anh, Ho Van; Van, Sach Nguyen; Tinh, Hien Tran; Day, Nicholas P. J.; Dondorp, Arjen; Thwaites, Guy; Faiz, Mohamed Abul; Phetsouvanh, Rattanaphone; Newton, Paul; Basnyat, Buddha; Farrar, Jeremy J.; Baker, Stephen

2015-01-01

Azithromycin is an effective treatment for uncomplicated infections with Salmonella enterica serovar Typhi and serovar Paratyphi A (enteric fever), but there are no clinically validated MIC and disk zone size interpretative guidelines. We studied individual patient data from three randomized controlled trials (RCTs) of antimicrobial treatment in enteric fever in Vietnam, with azithromycin used in one treatment arm, to determine the relationship between azithromycin treatment response and the azithromycin MIC of the infecting isolate. We additionally compared the azithromycin MIC and the disk susceptibility zone sizes of 1,640 S. Typhi and S. Paratyphi A clinical isolates collected from seven Asian countries. In the RCTs, 214 patients who were treated with azithromycin at a dose of 10 to 20 mg/ml for 5 to 7 days were analyzed. Treatment was successful in 195 of 214 (91%) patients, with no significant difference in response (cure rate, fever clearance time) with MICs ranging from 4 to 16 μg/ml. The proportion of Asian enteric fever isolates with an MIC of ≤16 μg/ml was 1,452/1,460 (99.5%; 95% confidence interval [CI], 98.9 to 99.7) for S. Typhi and 207/240 (86.3%; 95% CI, 81.2 to 90.3) (P < 0.001) for S. Paratyphi A. A zone size of ≥13 mm to a 5-μg azithromycin disk identified S. Typhi isolates with an MIC of ≤16 μg/ml with a sensitivity of 99.7%. An azithromycin MIC of ≤16 μg/ml or disk inhibition zone size of ≥13 mm enabled the detection of susceptible S. Typhi isolates that respond to azithromycin treatment. Further work is needed to define the response to treatment in S. Typhi isolates with an azithromycin MIC of >16 μg/ml and to determine MIC and disk breakpoints for S. Paratyphi A. PMID:25733500

Identification and Characterization of a Cis Antisense RNA of the rpoH Gene of Salmonella enterica Serovar Typhi.

PubMed

Xiong, Changyan; Li, Xuejiao; Liu, Juanli; Zhao, Xin; Xu, Shungao; Huang, Xinxiang

2018-01-01

Antisense RNAs from complementary strands of protein coding genes regulate the expression of genes involved in many cellular processes. Using deep sequencing analysis of the Salmonella enterica serovar Typhi ( S. Typhi) transcriptome, a novel antisense RNA encoded on the strand complementary to the rpoH gene was revealed. In this study, the molecular features of this antisense RNA were assessed using northern blotting and rapid amplification of cDNA ends. The 3,508 nt sequence of RNA was identified as the antisense RNA of the rpoH gene and was named ArpH. ArpH was found to attenuate the invasion of HeLa cells by S. Typhi by regulating the expression of SPI-1 genes. In an rpoH mutant strain, the invasive capacity of S. Typhi was increased, whereas overexpression of ArpH positively regulates rpoH mRNA levels. Results of this study suggest that the cis -encoded antisense RNA ArpH is likely to affect the invasive capacity of S. Typhi by regulating the expression of rpoH .

Antibacterial effect of mango (Mangifera indica Linn.) leaf extract against antibiotic sensitive and multi-drug resistant Salmonella typhi.

PubMed

Hannan, Abdul; Asghar, Samra; Naeem, Tahir; Ikram Ullah, Muhammad; Ahmed, Ijaz; Aneela, Syeda; Hussain, Shabbir

2013-07-01

Alternative herbal medicine has been used to treat various infections from centuries. Natural plants contain phytoconstituents having similar chemical properties as of synthetic antibiotics. Typhoid fever is a serious infection and failure of its treatment emerged multi-drug resistant (MDR) bugs of Salmonella typhi. Due to multiple and repeated issues with antibiotics efficacy, it became essential to evaluate biological properties of plants from different geographical origins. Mango leaves have been Reported for various medicinal effects like antioxidant, antimicrobial, antihelminthic, antidiabetic and antiallergic etc. Objective of present study was to investigate anti-typhoid properties of acetone mango leaf extract (AMLE) against antibiotic sensitive and MDR S. typhi isolates. A total of 50 isolates of S. typhi including MDR (n=30) and antibiotic sensitive (n=20) were investigated. Staphylococcus aureus (ATCC 25923) and Salmonella typhimurium (ATCC14028) were used as quality control strains. AMLE was prepared and its antibacterial activity was evaluated by agar well diffusion screening method and minimum inhibitory concentration (MIC), by agar dilution technique. Zone of inhibition (mm) of AMLE against MDR and antibiotic sensitive isolates was 18±1.5mm (Mean±S.D). Zone of S. aureus (ATCC 25923) and S. typhimurium (ATCC14028) was 20±1.5mm (Mean±S.D). MIC of AMLE was Reported in range from 10-50 mg/ml. The present study described the inhibitory effects of mango leaves against S. typhi.

R Factors in Strains of Salmonella typhi and Shigella dysenteriae 1 Isolated During Epidemics in Mexico: Classification by Compatibility

PubMed Central

Datta, Naomi; Olarte, J.

1974-01-01

All 17 Salmonella typhi strains tested from the epidemic in Mexico carried R factors of compatibility group H, conferring resistance to chloramphenicol, streptomycin, tetracycline, and sulfonamides. Some S. typhi strains carried, in addition, non-conjugative, ampicillin resistance plasmids and R factors of the I or A–C complex. All 20 Shigella dysenteriae 1 strains tested of epidemic origin carried O-group R factors. Ampicillin resistance in S. dysenteriae 1 was not proved to be plasmid borne. R factors of group H were not identified in any of the tested Mexican isolates other than S. typhi, but R factors of group O were identified in Escherichia coli, Shigella flexneri, and one strain of S. typhi, as well as in the epidemic S. dysenteriae. An R factor was identified which seemed to have two compatibility specificities, groups Iω and O. PMID:4599123

Temporal Fluctuation of Multidrug Resistant Salmonella Typhi Haplotypes in the Mekong River Delta Region of Vietnam

PubMed Central

Chau, Tran Thuy; Duy, Pham Thanh; La, Tran Thi Phi; Hoang, Nguyen Van Minh; Nga, Tran Vu Thieu; Campbell, James I.; Manh, Bui Huu; Vinh Chau, Nguyen Van; Hien, Tran Tinh; Farrar, Jeremy; Dougan, Gordon; Baker, Stephen

2011-01-01

Background Typhoid fever remains a public health problem in Vietnam, with a significant burden in the Mekong River delta region. Typhoid fever is caused by the bacterial pathogen Salmonella enterica serovar Typhi (S. Typhi), which is frequently multidrug resistant with reduced susceptibility to fluoroquinolone-based drugs, the first choice for the treatment of typhoid fever. We used a GoldenGate (Illumina) assay to type 1,500 single nucleotide polymorphisms (SNPs) and analyse the genetic variation of S. Typhi isolated from 267 typhoid fever patients in the Mekong delta region participating in a randomized trial conducted between 2004 and 2005. Principal Findings The population of S. Typhi circulating during the study was highly clonal, with 91% of isolates belonging to a single clonal complex of the S. Typhi H58 haplogroup. The patterns of disease were consistent with the presence of an endemic haplotype H58-C and a localised outbreak of S. Typhi haplotype H58-E2 in 2004. H58-E2-associated typhoid fever cases exhibited evidence of significant geo-spatial clustering along the Sông H u branch of the Mekong River. Multidrug resistance was common in the established clone H58-C but not in the outbreak clone H58-E2, however all H58 S. Typhi were nalidixic acid resistant and carried a Ser83Phe amino acid substitution in the gyrA gene. Significance The H58 haplogroup dominates S. Typhi populations in other endemic areas, but the population described here was more homogeneous than previously examined populations, and the dominant clonal complex (H58-C, -E1, -E2) observed in this study has not been detected outside Vietnam. IncHI1 plasmid-bearing S. Typhi H58-C was endemic during the study period whilst H58-E2, which rarely carried the plasmid, was only transient, suggesting a selective advantage for the plasmid. These data add insight into the outbreak dynamics and local molecular epidemiology of S. Typhi in southern Vietnam. PMID:21245916

Occurrence of ß-lactamase genes among non-Typhi Salmonella enterica isolated from humans, food animals, and retail meats in the United States and Canada

USDA-ARS?s Scientific Manuscript database

Non-Typhi Salmonella cause over 1.7 million cases of gastroenteritis in North America each year, and food-animal products are commonly implicated in human infections. For invasive infections, antimicrobial therapy is implicated. In North America, the antimicrobial susceptibility of Salmonella is m...

Oral Wild-Type Salmonella Typhi Challenge Induces Activation of Circulating Monocytes and Dendritic Cells in Individuals Who Develop Typhoid Disease.

PubMed

Toapanta, Franklin R; Bernal, Paula J; Fresnay, Stephanie; Darton, Thomas C; Jones, Claire; Waddington, Claire S; Blohmke, Christoph J; Dougan, Gordon; Angus, Brian; Levine, Myron M; Pollard, Andrew J; Sztein, Marcelo B

2015-06-01

A new human oral challenge model with wild-type Salmonella Typhi (S. Typhi) was recently developed. In this model, ingestion of 104 CFU of Salmonella resulted in 65% of subjects developing typhoid fever (referred here as typhoid diagnosis -TD-) 5-10 days post-challenge. TD criteria included meeting clinical (oral temperature ≥38°C for ≥12 h) and/or microbiological (S. Typhi bacteremia) endpoints. One of the first lines of defense against pathogens are the cells of the innate immune system (e.g., monocytes, dendritic cells -DCs-). Various changes in circulating monocytes and DCs have been described in the murine S. Typhimurium model; however, whether similar changes are present in humans remains to be explored. To address these questions, a subset of volunteers (5 TD and 3 who did not develop typhoid despite oral challenge -NoTD-) were evaluated for changes in circulating monocytes and DCs. Expression of CD38 and CD40 were upregulated in monocytes and DCs in TD volunteers during the disease days (TD-0h to TD-96h). Moreover, integrin α4β7, a gut homing molecule, was upregulated on monocytes but not DCs. CD21 upregulation was only identified in DCs. These changes were not observed among NoTD volunteers despite the same oral challenge. Moreover, monocytes and DCs from NoTD volunteers showed increased binding to S. Typhi one day after challenge. These monocytes showed phosphorylation of p38MAPK, NFkB and Erk1/2 upon stimulation with S. Typhi-LPS-QDot micelles. In contrast, monocytes from TD volunteers showed only a moderate increase in S. Typhi binding 48 h and 96 h post-TD, and only Erk1/2 phosphorylation. This is the first study to describe different activation and migration profiles, as well as differential signaling patterns, in monocytes and DCs which relate directly to the clinical outcome following oral challenge with wild type S. Typhi.

Towards a human oral vaccine for anthrax: the utility of a Salmonella Typhi Ty21a-based prime-boost immunization strategy.

PubMed

Baillie, Leslie W J; Rodriguez, Ana L; Moore, Stephen; Atkins, Helen S; Feng, Chiguang; Nataro, James P; Pasetti, Marcela F

2008-11-11

We previously demonstrated the ability of an orally administered attenuated Salmonella enterica serovar Typhimurium strain expressing the protective antigen (PA) of Bacillus anthracis to confer protection against lethal anthrax aerosol spore challenge [Stokes MG, Titball RW, Neeson BN, et al. Oral administration of a Salmonella enterica-based vaccine expressing Bacillus anthracis protective antigen confers protection against aerosolized B. anthracis. Infect Immun 2007;75(April (4)):1827-34]. To extend the utility of this approach to humans we constructed variants of S. enterica serovar Typhi Ty21a, an attenuated typhoid vaccine strain licensed for human use, which expressed and exported PA via two distinct plasmid-based transport systems: the Escherichia coli HlyA haemolysin and the S. Typhi ClyA export apparatus. Murine immunogenicity studies confirmed the ability of these constructs, especially Ty21a expressing the ClyA-PA fusion protein, to stimulate strong PA-specific immune responses following intranasal immunization. These responses were further enhanced by a subsequent boost with either parenterally delivered recombinant PA or the licensed US human alum-adsorbed anthrax vaccine (AVA). Anthrax toxin neutralizing antibody responses using this prime-boost regimen were rapid, vigorous and broad in nature. The results of this study demonstrate the feasibility of employing a mucosal prime with a licensed Salmonella Typhi vaccine strain followed by a parenteral protein boost to stimulate rapid protective immunity against anthrax.

CRISPR Is an Optimal Target for the Design of Specific PCR Assays for Salmonella enterica Serotypes Typhi and Paratyphi A

PubMed Central

Fabre, Laetitia; Le Hello, Simon; Roux, Chrystelle; Issenhuth-Jeanjean, Sylvie; Weill, François-Xavier

2014-01-01

Background Serotype-specific PCR assays targeting Salmonella enterica serotypes Typhi and Paratyphi A, the causal agents of typhoid and paratyphoid fevers, are required to accelerate formal diagnosis and to overcome the lack of typing sera and, in some situations, the need for culture. However, the sensitivity and specificity of such assays must be demonstrated on large collections of strains representative of the targeted serotypes and all other bacterial populations producing similar clinical symptoms. Methodology Using a new family of repeated DNA sequences, CRISPR (clustered regularly interspaced short palindromic repeats), as a serotype-specific target, we developed a conventional multiplex PCR assay for the detection and differentiation of serotypes Typhi and Paratyphi A from cultured isolates. We also developed EvaGreen-based real-time singleplex PCR assays with the same two sets of primers. Principal findings We achieved 100% sensitivity and specificity for each protocol after validation of the assays on 188 serotype Typhi and 74 serotype Paratyphi A strains from diverse genetic groups, geographic origins and time periods and on 70 strains of bacteria frequently encountered in bloodstream infections, including 29 other Salmonella serotypes and 42 strains from 38 other bacterial species. Conclusions The performance and convenience of our serotype-specific PCR assays should facilitate the rapid and accurate identification of these two major serotypes in a large range of clinical and public health laboratories with access to PCR technology. These assays were developed for use with DNA from cultured isolates, but with modifications to the assay, the CRISPR targets could be used in the development of assays for use with clinical and other samples. PMID:24498453

Genotyping of Salmonella enterica serovar Typhi strains isolated from 1959 to 2006 in China and analysis of genetic diversity by genomic microarray.

PubMed

Zhang, Haifang; Zhang, Xiaolei; Yan, Meiying; Pang, Bo; Kan, Biao; Xu, Huaxi; Huang, Xinxiang

2011-12-15

To determine the genotype of Salmonella enterica serovar Typhi (S. Typhi) strains in China and analyze their genetic diversity. We collected S. Typhi strains from 1959 to 2006 in five highly endemic Chinese provinces and chose 40 representative strains. Multilocus sequence typing was used to determine the genotypes or sequence types (ST) and microarray-based comparative genomic hybridization (M-CGH) to investigate the differences in gene content among these strains. Forty representative S. Typhi strains belonged to 4 sequence types (ST1, ST2, ST890, and ST892). The predominant S. Typhi genotype (31/40) was ST2 and it had a diverse geographic distribution. We discovered two novel STs - ST890 and ST892. M-CGH showed that 69 genes in these two novel STs were divergent from S. Typhi Ty2, which belongs to ST1. In addition, 5 representative Typhi strains of ST2 isolated from Guizhou province showed differences in divergent genes. We determined two novel sequence types, ST890 and ST892, and found that ST2 was the most prevalent genotype of S. Typhi in China. Genetic diversity was present even within a highly clonal bacterial population.

Epidemiology, clinical manifestations, and molecular typing of salmonella typhi isolated from patients with typhoid fever in Lebanon.

PubMed

Kanj, Souha S; Kanafani, Zeina A; Shehab, Marwa; Sidani, Nisreen; Baban, Tania; Baltajian, Kedak; Dakdouki, Ghenwa K; Zaatari, Mohamad; Araj, George F; Wakim, Rima Hanna; Dbaibo, Ghassan; Matar, Ghassan M

2015-06-01

The objective of this study was to examine the epidemiology and the clinical manifestations of typhoid fever as well as the susceptibility and strain relatedness of Salmonella typhi isolates in Lebanon from 2006 to 2007. A total of 120 patients with typhoid fever were initially identified from various areas of the country based on positive culture results for S. typhi from blood, urine, stools, bone marrow and/or positive serology. Clinical, microbiological and molecular analysis was performed on cases with complete data available. These results indicated that drinking water was an unlikely mode of transmission of the infection. Despite increasing reports of antimicrobial resistance among S. typhi isolates, the vast majority of these isolates were susceptible to various antibiotic agents, including ampicillin, cephalosporins, quinolones, and trimethoprim/sulfamethoxazole. Molecular analysis of the isolates revealed a predominance of one single genotype with no variation in distribution across the geographical regions. Copyright © 2014 Ministry of Health, Saudi Arabia. Published by Elsevier Ltd. All rights reserved.

Antimicrobial Drug Resistance of Salmonella enterica Serovar Typhi in Asia and Molecular Mechanism of Reduced Susceptibility to the Fluoroquinolones▿

PubMed Central

Chau, Tran Thuy; Campbell, James Ian; Galindo, Claudia M.; Van Minh Hoang, Nguyen; Diep, To Song; Nga, Tran Thu Thi; Van Vinh Chau, Nguyen; Tuan, Phung Quoc; Page, Anne Laure; Ochiai, R. Leon; Schultsz, Constance; Wain, John; Bhutta, Zulfiqar A.; Parry, Christopher M.; Bhattacharya, Sujit K.; Dutta, Shanta; Agtini, Magdarina; Dong, Baiqing; Honghui, Yang; Anh, Dang Duc; Canh, Do Gia; Naheed, Aliya; Albert, M. John; Phetsouvanh, Rattanaphone; Newton, Paul N.; Basnyat, Buddha; Arjyal, Amit; La, Tran Thi Phi; Rang, Nguyen Ngoc; Phuong, Le Thi; Van Be Bay, Phan; von Seidlein, Lorenz; Dougan, Gordon; Clemens, John D.; Vinh, Ha; Hien, Tran Tinh; Chinh, Nguyen Tran; Acosta, Camilo J.; Farrar, Jeremy; Dolecek, Christiane

2007-01-01

This study describes the pattern and extent of drug resistance in 1,774 strains of Salmonella enterica serovar Typhi isolated across Asia between 1993 and 2005 and characterizes the molecular mechanisms underlying the reduced susceptibilities to fluoroquinolones of these strains. For 1,393 serovar Typhi strains collected in southern Vietnam, the proportion of multidrug resistance has remained high since 1993 (50% in 2004) and there was a dramatic increase in nalidixic acid resistance between 1993 (4%) and 2005 (97%). In a cross-sectional sample of 381 serovar Typhi strains from 8 Asian countries, Bangladesh, China, India, Indonesia, Laos, Nepal, Pakistan, and central Vietnam, collected in 2002 to 2004, various rates of multidrug resistance (16 to 37%) and nalidixic acid resistance (5 to 51%) were found. The eight Asian countries involved in this study are home to approximately 80% of the world's typhoid fever cases. These results document the scale of drug resistance across Asia. The Ser83→Phe substitution in GyrA was the predominant alteration in serovar Typhi strains from Vietnam (117/127 isolates; 92.1%). No mutations in gyrB, parC, or parE were detected in 55 of these strains. In vitro time-kill experiments showed a reduction in the efficacy of ofloxacin against strains harboring a single-amino-acid substitution at codon 83 or 87 of GyrA; this effect was more marked against a strain with a double substitution. The 8-methoxy fluoroquinolone gatifloxacin showed rapid killing of serovar Typhi harboring both the single- and double-amino-acid substitutions. PMID:17908946

Lactose-fermenting, multiple drug-resistant Salmonella typhi strains isolated from a patient with postoperative typhoid fever.

PubMed Central

Kohbata, S; Takahashi, M; Yabuuchi, E

1983-01-01

Two lactose-fermenting Salmonella typhi strains were isolated from bile and blood specimens of a typhoid fever patient who underwent a cholecystectomy due to cholelithiasis. One lactose-fermenting S. typhi strain was also isolated from a pus specimen which was obtained at the tip of the T-shaped tube withdrawn from the operative wound of the common bile duct of the patient. These three lactose-fermenting isolates: GIFU 11924 from bile, GIFU 11926 from pus, and GIFU 11927 from blood, were phenotypically identical to the type strain (GIFU 11801 = ATCC 19430 = NCTC 8385) of S. typhi, except that the three strains fermented lactose and failed to blacken the butt of Kligler iron agar or triple sugar iron agar medium. All three lactose-fermenting strains were resistant to chloramphenicol, ampicillin, sulfomethoxazole, trimethoprim, gentamicin, cephaloridine, and four other antimicrobial agents. The type strain was uniformly susceptible to these 10 drugs. The strain GIFU 11925, a lactose-negative dissociant from strain GIFU 11926, was also susceptible to these drugs, with the sole exception of chloramphenicol (minimal inhibitory concentration, 100 micrograms/ml). PMID:6630471

Anti-biofilm efficacy of 100 MeV gold ion irradiated polycarbonate against Salmonella typhi

NASA Astrophysics Data System (ADS)

Joshi, R. P.; Hareesh, K.; Bankar, A.; Sanjeev, G.; Asokan, K.; Kanjilal, D.; Dahiwale, S. S.; Bhoraskar, V. N.; Dhole, S. D.

2017-12-01

Polycarbonate (PC) films were irradiated by 100 MeV gold (Au7+) ions and characterized to study changes in its optical, chemical, surface morphology and thermal properties. UV-Visible spectroscopic results revealed the decrease in the optical band gap of PC after ion irradiation due to chain scission mainly at the carbonyl group which is corroborated by Fourier Transform Infrared spectroscopic results. X-ray diffractogram study showed decrease in crystallinity of PC film after irradiation. Scanning electron microscopic results showed the micropores formation in PC which results in surface roughening. Differential scanning calorimetric results revealed decrease in glass transition temperature indicating the decrease in molecular weight of PC corroborated by rheometric studies. PC films irradiated by 100 MeV Au7+ ions showed increased anti-biofilm activity against the human pathogen, Salmonella typhi (S. typhi). Morphology of S. typhi was changed due to stress of Au7+ irradiated PC. Cells length was increased with increasing fluences. The average cell length, cell volume and surface area was increased significantly (P<0.05) with increasing ion fluences. Biofilm formation was inhibited ≈ 20% at lower fluence and 96% at higher fluence, which observed to be enhanced anti-biofilm activity in Au7+ irradiated PC.

Towards a human oral vaccine for anthrax: the utility of a Salmonella Typhi Ty21a-based prime boost immunization strategy

PubMed Central

Baillie, Leslie W.J.; Rodriguez, Ana L.; Moore, Stephen; Atkins, Helen S.; Feng, Chiguang; Nataro, James P.; Pasetti, Marcela F.

2008-01-01

We previously demonstrated the ability of an orally administered attenuated Salmonella enterica serovar Typhimurium strain expressing the protective antigen (PA) of Bacillus anthracis to confer protection against lethal anthrax aerosol spore challenge [1]. To extend the utility of this approach to humans we constructed variants of S. enterica serovar Typhi Ty21a, an attenuated typhoid vaccine strain licensed for human use, which expressed and exported PA via two distinct plasmid-based transport systems: the Escherichia coli HlyA haemolysin and the S. Typhi ClyA export apparatus. Murine immunogenicity studies confirmed the ability of these constructs, especially Ty21a expressing the ClyA-PA fusion protein, to stimulate strong PA-specific immune responses following intranasal immunization. These responses were further enhanced by a subsequent boost with either parenterally delivered recombinant PA or the licensed US human alum-adsorbed anthrax vaccine (AVA). Anthrax toxin neutralizing antibody responses using this prime-boost regimen were rapid, vigorous and broad in nature. The results of this study demonstrate the feasibility of employing a mucosal prime with a licensed Salmonella Typhi vaccine strain followed by a parenteral protein boost to stimulate rapid protective immunity against anthrax. PMID:18805452

Salmonella Typhi-specific multifunctional CD8+ T cells play a dominant role in protection from typhoid fever in humans.

PubMed

Fresnay, Stephanie; McArthur, Monica A; Magder, Laurence; Darton, Thomas C; Jones, Claire; Waddington, Claire S; Blohmke, Christoph J; Angus, Brian; Levine, Myron M; Pollard, Andrew J; Sztein, Marcelo B

2016-03-01

Typhoid fever, caused by the human-restricted organism Salmonella Typhi (S. Typhi), is a major public health problem worldwide. Development of novel vaccines remains imperative, but is hampered by an incomplete understanding of the immune responses that correlate with protection. Recently, a controlled human infection model was re-established in which volunteers received ~10(3) cfu wild-type S. Typhi (Quailes strain) orally. Twenty-one volunteers were evaluated for their cell-mediated immune (CMI) responses. Ex vivo PBMC isolated before and up to 1 year after challenge were exposed to three S. Typhi-infected targets, i.e., autologous B lymphoblastoid cell-lines (B-LCL), autologous blasts and HLA-E restricted AEH B-LCL cells. CMI responses were evaluated using 14-color multiparametric flow cytometry to detect simultaneously five intracellular cytokines/chemokines (i.e., IL-17A, IL-2, IFN-g, TNF-a and MIP-1b) and a marker of degranulation/cytotoxic activity (CD107a). Herein we provide the first evidence that S. Typhi-specific CD8+ responses correlate with clinical outcome in humans challenged with wild-type S. Typhi. Higher multifunctional S. Typhi-specific CD8+ baseline responses were associated with protection against typhoid and delayed disease onset. Moreover, following challenge, development of typhoid fever was accompanied by decreases in circulating S. Typhi-specific CD8+ T effector/memory (TEM) with gut homing potential, suggesting migration to the site(s) of infection. In contrast, protection against disease was associated with low or no changes in circulating S. Typhi-specific TEM. These studies provide novel insights into the protective immune responses against typhoid disease that will aid in selection and development of new vaccine candidates.

Selection of Salmonella enterica Serovar Typhi Genes Involved during Interaction with Human Macrophages by Screening of a Transposon Mutant Library

PubMed Central

Sabbagh, Sébastien C.; Lepage, Christine; McClelland, Michael; Daigle, France

2012-01-01

The human-adapted Salmonella enterica serovar Typhi (S. Typhi) causes a systemic infection known as typhoid fever. This disease relies on the ability of the bacterium to survive within macrophages. In order to identify genes involved during interaction with macrophages, a pool of approximately 105 transposon mutants of S. Typhi was subjected to three serial passages of 24 hours through human macrophages. Mutants recovered from infected macrophages (output) were compared to the initial pool (input) and those significantly underrepresented resulted in the identification of 130 genes encoding for cell membrane components, fimbriae, flagella, regulatory processes, pathogenesis, and many genes of unknown function. Defined deletions in 28 genes or gene clusters were created and mutants were evaluated in competitive and individual infection assays for uptake and intracellular survival during interaction with human macrophages. Overall, 26 mutants had defects in the competitive assay and 14 mutants had defects in the individual assay. Twelve mutants had defects in both assays, including acrA, exbDB, flhCD, fliC, gppA, mlc, pgtE, typA, waaQGP, SPI-4, STY1867-68, and STY2346. The complementation of several mutants by expression of plasmid-borne wild-type genes or gene clusters reversed defects, confirming that the phenotypic impairments within macrophages were gene-specific. In this study, 35 novel phenotypes of either uptake or intracellular survival in macrophages were associated with Salmonella genes. Moreover, these results reveal several genes encoding molecular mechanisms not previously known to be involved in systemic infection by human-adapted typhoidal Salmonella that will need to be elucidated. PMID:22574205

The influence of MAP condition and active compounds on the radiosensitization of Escherichia coli and Salmonella typhi present in chicken breast

NASA Astrophysics Data System (ADS)

Lacroix, M.; Chiasson, F.

2004-09-01

The efficiency of carvacrol, thymol, trans-cinnamaldehyde (Tc) and tetrasodium pyrophosphate (Tp) on the radiosensitization of Escherichia coli and Salmonella typhi in chicken breast was determined. Chicken breast were dipped in a bath of working cultures of E. coli or S. typhi (5×10 7 CFU/ml). Active compounds were added at the concentration corresponding to {1}/{30} of the minimal inhibitory concentration. Samples were packed under air and gamma irradiation was done at doses from 0.1 to 0.7 kGy. The efficiencies of the active compounds against E. coli were 32%, 10%, 3% and 0% for thymol, Tp and carvacrol, respectively. For S. typhi, the efficiencies in the chicken breast were 47%, 19%, 17% and 11% for Tc, Tp, carvacrol and thymol, respectively. Without active compounds, D10 values were 0.145 kGy for E. coli and 0.64 kGy for S. typhi as compared to 0.098 kGy for E. coli and 0.341 kGy for S. typhi in presence of Tc. Under modified atmospheric packaging condition and in presence of Tc, D10 values were reduced to 0.046 for E. coli and to 0.110 for S. typhi.

Characterization of antimicrobial resistance, molecular and phage types of Salmonella enterica serovar Typhi isolations.

PubMed

Demczuk, W H B; Finley, R; Nadon, C; Spencer, A; Gilmour, M; Ng, L-K

2010-10-01

Isolation rates in Canada of Salmonella enterica serovar Typhi increased from 0.29 to 0.55 isolations/100,000 population during 2000-2006. Although no ciprofloxacin resistance was detected, nalidixic acid resistance increased from 41% to 80%. Multidrug-resistant S. Typhi represented 18% of the strains tested. Pulsed-field gel electrophoresis (PFGE) analysis of 222 isolates resulted in 91 distinct patterns clustering into four major genetic similarity groups. The five most frequently occurring PFGE patterns accounted for 46% of the isolates. Drug-resistant isolates predominantly occurred in one PFGE similarity group. There were 39 phage types identified in 826 isolates analysed with 60% described by five phage types; 134 were untypable. The phage types associated with multidrug resistance were phage types 53, B1, D1, E1, E9, G3 and M1. Improved integration of epidemiological and laboratory case data will facilitate the protection of public health in Canada during an era of increasing travel and globalization.

Functional selection of a type IV pili-binding peptide that specifically inhibits Salmonella Typhi adhesion to/invasion of human monocytic cells.

PubMed

Wu, Hong-Yan; Zhang, Xiao-Lian; Pan, Qin; Wu, Jianguo

2005-11-01

Salmonella enterica serovar Typhi (S. Typhi) is an important pathogen which infects humans exclusively and causes typhoid or enteric fever. Recently it has been discovered that type IVB pili, encoded by the S. Typhi pil operon located in the major pathogenicity island, may be important in the pathogenesis of epidemic enteric fever. To further investigate the roles of type IVB pili of S. Typhi, a 12-mer peptide (RQERSSLSKPVV), binding to the structural protein PilS of the type IVB pili of S. Typhi, was isolated with a ribosome display system. This peptide was designated as peptide R. We found that peptide R inhibited adhesion to/invasion of human monocytic THP-1 cells by piliated S. Typhi bacteria, but had no effects on nonpiliated S. Typhi bacteria. A random 12-mer peptide, of size and solubility equal to peptide R, served as a control on the specificity of peptide R. The specific interaction and binding equilibrium between the 12-mer peptide R and PilS protein was determined by isothermal titration calorimetry (ITC) and a binding constant Ka determined to be between 0.4 x 10(5) and 2.2 x 10(5)L mol(-1). Our findings suggest that the type IV pili-binding peptide R holds potential as an antibacterial peptide effective against S. Typhi infections, both in terms of prevention and therapeutic treatment. The data further provide insights into the understanding of the pathogenic roles of the type IVB pili of S. Typhi.

Salmonella enterica Serovar Typhi Lipopolysaccharide O-Antigen Modification Impact on Serum Resistance and Antibody Recognition

DOE PAGES

Kintz, Erica; Heiss, Christian; Black, Ian; ...

2017-02-06

Salmonella enterica serovar Typhi is a human-restricted Gram-negative bacterial pathogen responsible for causing an estimated 27 million cases of typhoid fever annually, leading to 217,000 deaths, and current vaccines do not offer full protection. The O-antigen side chain of the lipopolysaccharide is an immunodominant antigen, can define host-pathogen interactions, and is under consideration as a vaccine target for some Gram-negative species. The composition of the O-antigen can be modified by the activity of glycosyltransferase (gtr) operons acquired by horizontal gene transfer. Here we investigate the role of two gtr operons that we identified in the S. Typhi genome. Strains weremore » engineered to express specific gtr operons. Full chemical analysis of the O-antigens of these strains identified gtr-dependent glucosylation and acetylation. The glucosylated form of the O-antigen mediated enhanced survival in human serum and decreased complement binding. A single nucleotide deviation from an epigenetic phase variation signature sequence rendered the expression of this glucosylating gtr operon uniform in the population. In contrast, the expression of the acetylating gtrC gene is controlled by epigenetic phase variation. Acetylation did not affect serum survival, but phase variation can be an immune evasion mechanism, and thus, this modification may contribute to persistence in a host. In murine immunization studies, both O-antigen modifications were generally immunodominant. Our results emphasize that natural O-antigen modifications should be taken into consideration when assessing responses to vaccines, especially O-antigen-based vaccines, and that the Salmonella gtr repertoire may confound the protective efficacy of broad-ranging Salmonella lipopolysaccharide conjugate vaccines.« less

Salmonella enterica Serovar Typhi Lipopolysaccharide O-Antigen Modification Impact on Serum Resistance and Antibody Recognition

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kintz, Erica; Heiss, Christian; Black, Ian

Salmonella enterica serovar Typhi is a human-restricted Gram-negative bacterial pathogen responsible for causing an estimated 27 million cases of typhoid fever annually, leading to 217,000 deaths, and current vaccines do not offer full protection. The O-antigen side chain of the lipopolysaccharide is an immunodominant antigen, can define host-pathogen interactions, and is under consideration as a vaccine target for some Gram-negative species. The composition of the O-antigen can be modified by the activity of glycosyltransferase (gtr) operons acquired by horizontal gene transfer. Here we investigate the role of two gtr operons that we identified in the S. Typhi genome. Strains weremore » engineered to express specific gtr operons. Full chemical analysis of the O-antigens of these strains identified gtr-dependent glucosylation and acetylation. The glucosylated form of the O-antigen mediated enhanced survival in human serum and decreased complement binding. A single nucleotide deviation from an epigenetic phase variation signature sequence rendered the expression of this glucosylating gtr operon uniform in the population. In contrast, the expression of the acetylating gtrC gene is controlled by epigenetic phase variation. Acetylation did not affect serum survival, but phase variation can be an immune evasion mechanism, and thus, this modification may contribute to persistence in a host. In murine immunization studies, both O-antigen modifications were generally immunodominant. Our results emphasize that natural O-antigen modifications should be taken into consideration when assessing responses to vaccines, especially O-antigen-based vaccines, and that the Salmonella gtr repertoire may confound the protective efficacy of broad-ranging Salmonella lipopolysaccharide conjugate vaccines.« less

Differential Epidemiology of Salmonella Typhi and Paratyphi A in Kathmandu, Nepal: A Matched Case Control Investigation in a Highly Endemic Enteric Fever Setting

PubMed Central

Tran Vu Thieu, Nga; Dongol, Sabina; Le Thi Phuong, Tu; Voong Vinh, Phat; Arjyal, Amit; Martin, Laura B.; Rondini, Simona; Farrar, Jeremy J.; Dolecek, Christiane; Basnyat, Buddha; Baker, Stephen

2013-01-01

Background Enteric fever, a systemic infection caused by the bacteria Salmonella Typhi and Salmonella Paratyphi A, is endemic in Kathmandu, Nepal. Previous work identified proximity to poor quality water sources as a community-level risk for infection. Here, we sought to examine individual-level risk factors related to hygiene and sanitation to improve our understanding of the epidemiology of enteric fever in this setting. Methodology and principal findings A matched case-control analysis was performed through enrollment of 103 blood culture positive enteric fever patients and 294 afebrile community-based age and gender-matched controls. A detailed questionnaire was administered to both cases and controls and the association between enteric fever infection and potential exposures were examined through conditional logistic regression. Several behavioral practices were identified as protective against infection with enteric fever, including water storage and hygienic habits. Additionally, we found that exposures related to poor water and socioeconomic status are more influential in the risk of infection with S. Typhi, whereas food consumption habits and migration play more of a role in risk of S. Paratyphi A infection. Conclusions and significance Our work suggests that S. Typhi and S. Paratyphi A follow different routes of infection in this highly endemic setting and that sustained exposure to both serovars probably leads to the development of passive immunity. In the absence of a polyvalent vaccine against S. Typhi and S. Paratyphi A, we advocate better systems for water treatment and storage, improvements in the quality of street food, and vaccination with currently available S. Typhi vaccines. PMID:23991240

First characterization of immunogenic conjugates of Vi negative Salmonella Typhi O-specific polysaccharides with rEPA protein for vaccine development.

PubMed

Salman, M; St Michael, F; Ali, A; Jabbar, A; Cairns, C; Hayes, A C; Rahman, M; Iqbal, M; Haque, A; Cox, A D

2017-11-01

Efficacious typhoid vaccines for young children will significantly reduce the disease burden in developing world. The Vi polysaccharide based conjugate vaccines (Vi-rEPA) against Salmonella Typhi Vi positive strains has shown high efficacy but may be ineffective against Vi negative S. Typhi. In this study, for the first time, we report the synthesis and evaluation of polysaccharide-protein conjugates of Vi negative S. Typhi as potential vaccine candidates. Four different conjugates were synthesized using recombinant exoprotein A of Pseudomonas aeruginosa (rEPA) and human serum albumin (HSA) as the carrier proteins, using either direct reductive amination or an intermediate linker molecule, adipic acid dihydrazide (ADH). Upon injection into mice, a significantly higher antibody titer was observed in mice administrated with conjugate-1 (OSP-HSA) (P=0.0001) and conjugate 2 (OSP-rEPA) (P≤0.0001) as compared to OSP alone. In contrast, the antibody titer elicited by conjugate 3 (OSP ADH -HSA) and conjugate 4 (OSP ADH -rEPA) were insignificant (P=0.1684 and P=0.3794, respectively). We conclude that reductive amination is the superior method to prepare the S. Typhi OSP glycoconjugate. Moreover, rEPA was a better carrier protein than HSA. Thus OSP-rEPA conjugate seems to be efficacious typhoid vaccines candidate, it may be evaluated further and recommended for the clinical trials. Crown Copyright © 2017. Published by Elsevier B.V. All rights reserved.

An evaluation of purified Salmonella Typhi protein antigens for the serological diagnosis of acute typhoid fever.

PubMed

Tran Vu Thieu, Nga; Trinh Van, Tan; Tran Tuan, Anh; Klemm, Elizabeth J; Nguyen Ngoc Minh, Chau; Voong Vinh, Phat; Pham Thanh, Duy; Ho Ngoc Dan, Thanh; Pham Duc, Trung; Langat, Pinky; Martin, Laura B; Galan, Jorge; Liang, Li; Felgner, Philip L; Davies, D Huw; de Jong, Hanna K; Maude, Rapeephan R; Fukushima, Masako; Wijedoru, Lalith; Ghose, Aniruddha; Samad, Rasheda; Dondorp, Arjen M; Faiz, Abul; Darton, Thomas C; Pollard, Andrew J; Thwaites, Guy E; Dougan, Gordon; Parry, Christopher M; Baker, Stephen

2017-08-01

The diagnosis of typhoid fever is a challenge. Aiming to develop a typhoid diagnostic we measured antibody responses against Salmonella Typhi (S. Typhi) protein antigens and the Vi polysaccharide in a cohort of Bangladeshi febrile patients. IgM against 12 purified antigens and the Vi polysaccharide was measured by ELISA in plasma from patients with confirmed typhoid fever (n = 32), other confirmed infections (n = 17), and healthy controls (n = 40). ELISAs with the most specific antigens were performed on plasma from 243 patients with undiagnosed febrile disease. IgM against the S. Typhi protein antigens correlated with each other (rho > 0.8), but not against Vi (rho < 0.6). Typhoid patients exhibited higher IgM against 11/12 protein antigens and Vi than healthy controls and those with other infections. Vi, PilL, and CdtB exhibited the greatest sensitivity and specificity. Specificity and sensitivity was improved when Vi was combined with a protein antigen, generating sensitivities and specificities of 0.80 and >0.85, respectively. Applying a dynamic cut-off to patients with undiagnosed febrile disease suggested that 34-58% had an IgM response indicative of typhoid. We evaluated the diagnostic potential of several S. Typhi antigens; our assays give good sensitivity and specificity, but require further assessment in differing patient populations. Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.

Simultaneous and Rapid Detection of Salmonella typhi, Bacillus anthracis, and Yersinia pestis by Using Multiplex Polymerase Chain Reaction (PCR)

PubMed Central

Safari Foroshani, Nargess; Karami, Ali; Pourali, Fatemeh

2013-01-01

Background Salmonella typhi, Bacillus anthracis, and Yersinia pestis are some serious human pathogens, which their early diagnosis is of great importance. Salmonella typhi, Bacillus anthracis, and Yersinia pestis cause typhoid fever, anthrax, and plague respectively. These bacteria can be used to make biologic weapons. Objectives In this study, we designed a new and rapid diagnostic method based on Uniplex and Multiplex PCR method. Materials and Methods Uniplex and multiplex Polymerase Chain Reaction (PCR) were conducted on virulent genes of hp and invA of Salmonella typhimurium, Pa and chr of Bacillus anthracis, and pla of Yersinia pestis. A genome from other bacteria was used to study the specificity of the primer and the PCR test. Results Standard strains used in this study showed that primers were specific. As for sensitivity, it was shown that this method can diagnose 1-10 copies of the genome, or 1-10 Colony Forming Units (CFU) for each of the bacteria. All pieces except anthrax were sequenced in PCR to validate the product. DNA fragment resulted from Bacillus anthracis was confirmed by restriction enzyme digestions. Conclusion The designed methods are accurate, rapid, and inexpensive to find and differentiate these bacteria from similar bacteria. They can be applied for rapid diagnosis of these agents in different specimens, and bioterrorism cases. PMID:24719692

Emergence of an Extensively Drug-Resistant Salmonella enterica Serovar Typhi Clone Harboring a Promiscuous Plasmid Encoding Resistance to Fluoroquinolones and Third-Generation Cephalosporins.

PubMed

Klemm, Elizabeth J; Shakoor, Sadia; Page, Andrew J; Qamar, Farah Naz; Judge, Kim; Saeed, Dania K; Wong, Vanessa K; Dallman, Timothy J; Nair, Satheesh; Baker, Stephen; Shaheen, Ghazala; Qureshi, Shahida; Yousafzai, Mohammad Tahir; Saleem, Muhammad Khalid; Hasan, Zahra; Dougan, Gordon; Hasan, Rumina

2018-02-20

Antibiotic resistance is a major problem in Salmonella enterica serovar Typhi, the causative agent of typhoid. Multidrug-resistant (MDR) isolates are prevalent in parts of Asia and Africa and are often associated with the dominant H58 haplotype. Reduced susceptibility to fluoroquinolones is also widespread, and sporadic cases of resistance to third-generation cephalosporins or azithromycin have also been reported. Here, we report the first large-scale emergence and spread of a novel S  Typhi clone harboring resistance to three first-line drugs (chloramphenicol, ampicillin, and trimethoprim-sulfamethoxazole) as well as fluoroquinolones and third-generation cephalosporins in Sindh, Pakistan, which we classify as extensively drug resistant (XDR). Over 300 XDR typhoid cases have emerged in Sindh, Pakistan, since November 2016. Additionally, a single case of travel-associated XDR typhoid has recently been identified in the United Kingdom. Whole-genome sequencing of over 80 of the XDR isolates revealed remarkable genetic clonality and sequence conservation, identified a large number of resistance determinants, and showed that these isolates were of haplotype H58. The XDR S  Typhi clone encodes a chromosomally located resistance region and harbors a plasmid encoding additional resistance elements, including the bla CTX-M-15 extended-spectrum β-lactamase, and carrying the qnrS fluoroquinolone resistance gene. This antibiotic resistance-associated IncY plasmid exhibited high sequence identity to plasmids found in other enteric bacteria isolated from widely distributed geographic locations. This study highlights three concerning problems: the receding antibiotic arsenal for typhoid treatment, the ability of S  Typhi to transform from MDR to XDR in a single step by acquisition of a plasmid, and the ability of XDR clones to spread globally. IMPORTANCE Typhoid fever is a severe disease caused by the Gram-negative bacterium Salmonella enterica serovar Typhi. Antibiotic

Use of a novel antigen expressing system to study the Salmonella enterica serovar Typhi protein recognition by T cells

PubMed Central

Lou, David; Steiner, Stephanie; Rezwanul, Tasmia; Guo, Qin; Picking, William D.; Nene, Vishvanath; Sztein, Marcelo B.

2017-01-01

Salmonella enterica serovar Typhi (S. Typhi), the causative agent of the typhoid fever, is a pathogen of great public health importance. Typhoid vaccines have the potential to be cost-effective measures towards combating this disease, yet the antigens triggering host protective immune responses are largely unknown. Given the key role of cellular-mediated immunity in S. Typhi protection, it is crucial to identify S. Typhi proteins involved in T-cell responses. Here, cells from individuals immunized with Ty21a typhoid vaccine were collected before and after immunization and used as effectors. We also used an innovative antigen expressing system based on the infection of B-cells with recombinant Escherichia coli (E. coli) expressing one of four S. Typhi gene products (i.e., SifA, OmpC, FliC, GroEL) as targets. Using flow cytometry, we found that the pattern of response to specific S. Typhi proteins was variable. Some individuals responded to all four proteins while others responded to only one or two proteins. We next evaluated whether T-cells responding to recombinant E. coli also possess the ability to respond to purified proteins. We observed that CD4+ cell responses, but not CD8+ cell responses, to recombinant E. coli were significantly associated with the responses to purified proteins. Thus, our results demonstrate the feasibility of using an E. coli expressing system to uncover the antigen specificity of T-cells and highlight its applicability to vaccine studies. These results also emphasize the importance of selecting the stimuli appropriately when evaluating CD4+ and CD8+ cell responses. PMID:28873442

Synergistic antimicrobial effect of nisin and p-cymene on Salmonella enterica serovar Typhi in vitro and on ready-to-eat food.

PubMed

Rattanachaikunsopon, Pongsak; Phumkhachorn, Parichat

2010-01-01

Foods contaminated with Salmonella enterica serovar Typhi are a major cause of typhoid fever, leading to public health problems and economic losses worldwide. Nisin and rho-cymene were tested in this study for their antimicrobial activity against S. Typhi at 4 degrees C and 37 degrees C. Nisin and rho-cymene, when used separately, did not inhibit the bacterium at either temperature. A synergistic antimicrobial effect between both compounds was observed when they were used simultaneously. This synergism was greater at 37 degrees C than at 4 degrees C. The lowest concentrations of nisin and rho-cymene required for complete inhibition of S. Typhi at 37 degrees C were 0.3 ppm and 1.5 ppm, respectively, and 0.3 ppm and 2.5 ppm at 4 degrees C. The potential of nisin and rho-cymene to control an S. Typhi population on ready-to-eat Thai-style pork sausage was also examined. The compounds were able to eliminate the contaminating bacterium with concentrations depending on the bacterial cell number on the food.

Cell-free culture supernatant of Bifidobacterium breve CNCM I-4035 decreases pro-inflammatory cytokines in human dendritic cells challenged with Salmonella typhi through TLR activation.

PubMed

Bermudez-Brito, Miriam; Muñoz-Quezada, Sergio; Gomez-Llorente, Carolina; Matencio, Esther; Bernal, Maria J; Romero, Fernando; Gil, Angel

2013-01-01

Dendritic cells (DCs) constitute the first point of contact between gut commensals and our immune system. Despite growing evidence of the immunomodulatory effects of probiotics, the interactions between the cells of the intestinal immune system and bacteria remain largely unknown. Indeed,, the aim of this work was to determine whether the probiotic Bifidobacterium breve CNCM I-4035 and its cell-free culture supernatant (CFS) have immunomodulatory effects in human intestinal-like dendritic cells (DCs) and how they respond to the pathogenic bacterium Salmonella enterica serovar Typhi, and also to elucidate the molecular mechanisms involved in these interactions. Human DCs were directly challenged with B. breve/CFS, S. typhi or a combination of these stimuli for 4 h. The expression pattern of genes involved in Toll-like receptor (TLR) signaling pathway and cytokine secretion was analyzed. CFS decreased pro-inflammatory cytokines and chemokines in human intestinal DCs challenged with S. typhi. In contrast, the B. breve CNCM I-4035 probiotic strain was a potent inducer of the pro-inflammatory cytokines and chemokines tested, i.e., TNF-α, IL-8 and RANTES, as well as anti-inflammatory cytokines including IL-10. CFS restored TGF-β levels in the presence of Salmonella. Live B.breve and its supernatant enhanced innate immune responses by the activation of TLR signaling pathway. These treatments upregulated TLR9 gene transcription. In addition, CFS was a more potent inducer of TLR9 expression than the probiotic bacteria in the presence of S. typhi. Expression levels of CASP8 and IRAK4 were also increased by CFS, and both treatments induced TOLLIP gene expression. Our results indicate that the probiotic strain B. breve CNCM I-4035 affects the intestinal immune response, whereas its supernatant exerts anti-inflammatory effects mediated by DCs. This supernatant may protect immune system from highly infectious agents such as Salmonella typhi and can down-regulate pro

Cell-Free Culture Supernatant of Bifidobacterium breve CNCM I-4035 Decreases Pro-Inflammatory Cytokines in Human Dendritic Cells Challenged with Salmonella typhi through TLR Activation

PubMed Central

Bermudez-Brito, Miriam; Muñoz-Quezada, Sergio; Gomez-Llorente, Carolina; Matencio, Esther; Bernal, Maria J.; Romero, Fernando; Gil, Angel

2013-01-01

Dendritic cells (DCs) constitute the first point of contact between gut commensals and our immune system. Despite growing evidence of the immunomodulatory effects of probiotics, the interactions between the cells of the intestinal immune system and bacteria remain largely unknown. Indeed,, the aim of this work was to determine whether the probiotic Bifidobacterium breve CNCM I-4035 and its cell-free culture supernatant (CFS) have immunomodulatory effects in human intestinal-like dendritic cells (DCs) and how they respond to the pathogenic bacterium Salmonella enterica serovar Typhi, and also to elucidate the molecular mechanisms involved in these interactions. Human DCs were directly challenged with B. breve/CFS, S. typhi or a combination of these stimuli for 4 h. The expression pattern of genes involved in Toll-like receptor (TLR) signaling pathway and cytokine secretion was analyzed. CFS decreased pro-inflammatory cytokines and chemokines in human intestinal DCs challenged with S. typhi. In contrast, the B. breve CNCM I-4035 probiotic strain was a potent inducer of the pro-inflammatory cytokines and chemokines tested, i.e., TNF-α, IL-8 and RANTES, as well as anti-inflammatory cytokines including IL-10. CFS restored TGF-β levels in the presence of Salmonella. Live B.breve and its supernatant enhanced innate immune responses by the activation of TLR signaling pathway. These treatments upregulated TLR9 gene transcription. In addition, CFS was a more potent inducer of TLR9 expression than the probiotic bacteria in the presence of S. typhi. Expression levels of CASP8 and IRAK4 were also increased by CFS, and both treatments induced TOLLIP gene expression. Our results indicate that the probiotic strain B. breve CNCM I-4035 affects the intestinal immune response, whereas its supernatant exerts anti-inflammatory effects mediated by DCs. This supernatant may protect immune system from highly infectious agents such as Salmonella typhi and can down-regulate pro

A 3' UTR-derived non-coding RNA RibS increases expression of cfa and promotes biofilm formation of Salmonella enterica serovar Typhi.

PubMed

Zhao, Xin; Liu, Rui; Tang, Hao; Osei-Adjei, George; Xu, Shungao; Zhang, Ying; Huang, Xinxiang

2018-05-08

Bacterial non-coding RNAs (ncRNAs) are widely studied and found to play important roles in regulating various cellular processes. Recently, many ncRNAs have been discovered to be transcribed or processed from 3' untranslated regions (3' UTRs). Here we reported a novel 3' UTR-derived ncRNA, RibS, which could influence biofilm formation of Salmonella enterica serovar Typhi (S. Typhi). RibS was confirmed to be a ∼700 nt processed product produced by RNase III-catalyzed cleavage from the 3' UTR of riboflavin synthase subunit alpha mRNA, RibE. Overexpression of RibS increased the expression of the cyclopropane fatty acid synthase gene, cfa, which was located at the antisense strand. Biofilm formation of S. Typhi was enhanced by overexpressing RibS both in the wild type strain and cfa deletion mutant. Deletion of cfa attenuated biofilm formation of S. Typhi, while complementation of cfa partly restored the phenotype. Moreover, overexpressing cfa enhanced the biofilm formation of S. Typhi. In summary, RibS has been identified as a novel ncRNA derived from the 3' UTR of RibE that promotes biofilm formation of S. Typhi, and it appears to do so, at least in part, by increasing the expression of cfa. Copyright © 2018 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

Immunoblot detection of class-specific humoral immune response to outer membrane proteins isolated from Salmonella typhi in humans with typhoid fever.

PubMed Central

Ortiz, V; Isibasi, A; García-Ortigoza, E; Kumate, J

1989-01-01

The studies reported here were undertaken to assess the ability of the outer membrane proteins (OMPs) of Salmonella typhi to induce a humoral immune response in humans with typhoid fever. OMPs were isolated with the nonionic detergent Triton X-100 and were found to be contaminated with approximately 4% lipopolysaccharide. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis patterns showed protein bands with molecular size ranges from 17 to 70 kilodaltons; the major groups of proteins were those that correspond to the porins and OmpA of gram-negative bacteria. Rabbit antiserum to OMPs or to S. typhi recognized OMPs after absorption with lipopolysaccharide. Sera from patients with typhoid fever contained immunoglobulin M antibodies which reacted with a protein of 28 kilodaltons and immunoglobulin G antibodies which reacted mainly with the porins, as determined by immunoblotting. These results indicate that the porins are the major immunogenic OMPs from S. typhi and that the immune response induced in the infection could be related to the protective status. Images PMID:2768450

Isolation of Salmonella Virchow from a fruit bat (Pteropus giganteus).

PubMed

Islam, Ausraful; Mikolon, Andrea; Mikoleit, Matthew; Ahmed, Dilruba; Khan, Salah Udddin; Sharker, M A Yushuf; Hossain, M Jahangir; Islam, Ariful; Epstein, Jonathan H; Zeidner, Nord; Luby, Stephen P

2013-12-01

Detection of zoonotic pathogens carried by bats is important both for understanding disease ecology and for developing preventive measures. Pteropus fruit bats have been identified as potential carriers of Salmonella enterica serotype Typhi. A cross-sectional study was conducted to determine the prevalence of Salmonella Typhi and other Salmonella serotypes in Pteropus giganteus fruit bats in Bangladesh. Rectal swabs were collected from 302 bats and cultured for Salmonella species. The bats were trapped in three districts (Faridpur, Rajbari, and Cox's Bazar). Salmonella Typhi was not found but one juvenile female bat from Faridpur district was positive for Salmonella Virchow. Close associations between frugivorous bats, humans, and livestock in rural Bangladesh make it likely that the bat was infected by consuming contaminated water.

Salmonella Infections (For Parents)

MedlinePlus

... iguanas). Another, rarer form — called Salmonella typhi — causes typhoid fever . What Is Salmonella Infection? Salmonella infection, or salmonellosis , ... More on this topic for: Parents Kids Teens Typhoid Fever E. Coli Stool Test: Bacteria Culture Food Safety ...

Functional assay of Salmonella typhi OmpC using reconstituted large unilamellar vesicles: a general method for characterization of outer membrane proteins.

PubMed

Sundara Baalaji, N; Mathew, M K; Krishnaswamy, S

2006-10-01

The immunodominant trimeric beta-barrel outer membrane protein OmpC from Salmonella typhi, the causative agent of typhoid, has been functionally characterized here. The activity in the vesicle environment was studied in vitro using OmpC reconstituted into proteoliposomes. Passage of polysaccharides and polyethyleneglycols through OmpC has been examined to determine the permeability properties. The relative rate of neutral solute flux yields a radius of 1.1 nm for the S. typhi OmpC pore. This is almost double the pore size of Escherichia coli. This provides an example of large pore size present in the porins that form trimers as in the general bacterial porin family. The method used in this study provides a good membrane model for functional studies of porins.

Whole Genome Sequence Analysis of Salmonella Typhi Isolated in Thailand before and after the Introduction of a National Immunization Program

PubMed Central

Thanh, Duy Pham; Bodhidatta, Ladaporn; Mason, Carl Jeffries; Srijan, Apichai; Rabaa, Maia A.; Vinh, Phat Voong; Thanh, Tuyen Ha; Thwaites, Guy E.; Baker, Stephen; Holt, Kathryn E.

2017-01-01

Vaccines against Salmonella Typhi, the causative agent of typhoid fever, are commonly used by travellers, however, there are few examples of national immunization programs in endemic areas. There is therefore a paucity of data on the impact of typhoid immunization programs on localised populations of S. Typhi. Here we have used whole genome sequencing (WGS) to characterise 44 historical bacterial isolates collected before and after a national typhoid immunization program that was implemented in Thailand in 1977 in response to a large outbreak; the program was highly effective in reducing typhoid case numbers. Thai isolates were highly diverse, including 10 distinct phylogenetic lineages or genotypes. Novel prophage and plasmids were also detected, including examples that were previously only reported in Shigella sonnei and Escherichia coli. The majority of S. Typhi genotypes observed prior to the immunization program were not observed following it. Post-vaccine era isolates were more closely related to S. Typhi isolated from neighbouring countries than to earlier Thai isolates, providing no evidence for the local persistence of endemic S. Typhi following the national immunization program. Rather, later cases of typhoid appeared to be caused by the occasional importation of common genotypes from neighbouring Vietnam, Laos, and Cambodia. These data show the value of WGS in understanding the impacts of vaccination on pathogen populations and provide support for the proposal that large-scale typhoid immunization programs in endemic areas could result in lasting local disease elimination, although larger prospective studies are needed to test this directly. PMID:28060810

Molecular typing and resistance analysis of travel-associated Salmonella enterica serotype Typhi.

PubMed

Tatavarthy, A; Sanderson, R; Peak, K; Scilabro, G; Davenhill, P; Cannons, A; Amuso, P

2012-08-01

Salmonella enterica serotype Typhi is a human pathogen causing 12 to 30% mortality and requiring antibiotic therapy to control the severity of the infection. Typhoid fever in United States is often associated with foreign travel to areas of endemicity. Increasing resistance to multiple drugs, including quinolones, is associated with decreased susceptibility to ciprofloxacin (DCS). We investigated 31 clinical strains isolated in Florida from 2007 to 2010, associated with travel to six countries, to examine the clonal distribution of the organism and apparent nalidixic acid (NAL) resistance. The strains were isolated from blood or stool of patients aged 2 to 68 years. The isolates were subtyped by ribotyping and pulsed-field gel electrophoresis. Susceptibilities to 15 antimicrobials were determined, and the isolates were screened for integrons and gyrase A gene mutations. Both typing techniques effectively segregated the strains. Identical clones were associated with different countries, while diverse types coexisted in the same geographic location. Fifty-one percent of the strains were resistant to at least one antimicrobial, and five were resistant to three or more drugs (multidrug resistant [MDR]). All 12 isolates from the Indian subcontinent were resistant to at least one drug, and 83% of those were resistant to NAL. Three of the MDR strains harbored a 750-bp integron containing the dfr7 gene. Ninety-three percent of the resistant strains showed a DCS profile. All the NAL-resistant strains contained point mutations in the quinolone resistance-determining region of gyrA. This study affirms the global clonal distribution, concomitant genetic heterogeneity, and increased NAL resistance of S. enterica serovar Typhi.

Laboratory-based Salmonella surveillance in Fiji, 2004-2005.

PubMed

Dunn, John; Pryor, Jan; Saketa, Salanieta; Delai, Wasale; Buadromo, Eka; Kishore, Kamal; Naidu, Shakila; Greene, Sharon; Varma, Jay; Chiller, Tom

2005-09-01

Although foodborne diseases are an important public health problem worldwide, the burden of foodborne illness is not well described in most Pacific Island Countries and Territories. Laboratory-based surveillance programs can detect trends and outbreaks, estimate burden of illness, and allow subtyping of enteric pathogens (e.g. Salmonella serotyping), which is critical for linking illness to food vehicles and animal reservoirs. To enhance public health capacity in Fiji for foodborne disease surveillance, we developed the Salmonella Surveillance Project (SSP), a collaboration to pilot laboratory-based surveillance for Salmonella. A network of national and international partners was formed including epidemiologists, microbiologists, and environmental health personnel. Ministry of Health personnel were trained in foodborne disease surveillance and outbreak investigation. Three clinical microbiology laboratories from different parts of the country functioned as sentinel sites, reporting all laboratory-confirmed Salmonella infections using a standardized case report form. Non-Typhi Salmonella isolates were collected for serotyping. In 2004-2005, 86 non-Typhi Salmonella and 275 S. Typhi laboratory-confirmed infections were reported. Salmonella enterica serotype I 3,10: r:- and Salmonella enterica serotype Weltevreden were the most commonly isolated non-Typhi serotypes. In Fiji, the SSP utilized international partnerships to facilitate training, and to enhance laboratory capacity and surveillance for salmonellosis. Incorporating laboratory-based foodborne disease reporting into national disease surveillance will enable public health officials to describe the burden of foodborne illness, identify outbreaks, conduct analytic epidemiology studies, and improve food safety.

Occurrence of small Hsd plasmids in Salmonella typhi, Shigella boydii, and Escherichia coli.

PubMed Central

Yoshida, Y; Mise, K

1986-01-01

The natural occurrence of small Hsd (host specificity for DNA) plasmids was demonstrated in restriction endonuclease-producing strains of Salmonella typhi, Shigella boydii, and Escherichia coli. The five Hsd plasmids isolated were between 5.0 and 12.2 kilobases long. The copy number of all the Hsd plasmids was high (more than 10 copies per cell). Introduction of these small plasmids into E. coli strain 0 drastically lowered the efficiency of plating of the lambda.0 phages (the efficiency of plating was less than 5 X 10(-5) PFU-1). High restriction endonuclease activities were detected in the Hsd plasmid-positive strains because of the elevated copy numbers of the hsdR+ gene. The advantages of using E. coli strains containing the small Hsd plasmids for purification of type II restriction endonucleases are discussed. Images PMID:3003023

Early diagnosis of typhoid fever by nested PCR for flagellin gene of Salmonella enterica serotype Typhi.

PubMed

Khan, S; Harish, B N; Menezes, G A; Acharya, N S; Parija, S C

2012-11-01

Typhoid fever caused by Salmonella Typhi continues to be a major health problem in spite of the use of antibiotics and the development of newer antibacterial drugs. Inability to make an early laboratory diagnosis and resort to empirical therapy, often lead to increased morbidity and mortality in cases of typhoid fever. This study was aimed to optimize a nested PCR for early diagnosis of typhoid fever and using it as a diagnostic tool in culture negative cases of suspected typhoid fever. Eighty patients with clinical diagnosis of typhoid fever and 40 controls were included in the study. The blood samples collected were subjected to culture, Widal and nested PCR targeting the flagellin gene of S. Typhi. The sensitivity of PCR on blood was found to be 100 per cent whereas the specificity was 76.9 per cent. The positive predictive value (PPV) of PCR was calculated to be 76.9 per cent with an accuracy of 86 per cent. None of the 40 control samples gave a positive PCR. Due to its high sensitivity and specificity nested PCR can be used as a useful tool to diagnose clinically suspected, culture negative cases of typhoid fever.

An Outpatient, Ambulant-Design, Controlled Human Infection Model Using Escalating Doses of Salmonella Typhi Challenge Delivered in Sodium Bicarbonate Solution

PubMed Central

Waddington, Claire S.; Darton, Thomas C.; Jones, Claire; Haworth, Kathryn; Peters, Anna; John, Tessa; Thompson, Ben A. V.; Kerridge, Simon A.; Kingsley, Robert A.; Zhou, Liqing; Holt, Kathryn E.; Yu, Ly-Mee; Lockhart, Stephen; Farrar, Jeremy J.; Sztein, Marcelo B.; Dougan, Gordon; Angus, Brian; Levine, Myron M.; Pollard, Andrew J.

2014-01-01

Background. Typhoid fever is a major global health problem, the control of which is hindered by lack of a suitable animal model in which to study Salmonella Typhi infection. Until 1974, a human challenge model advanced understanding of typhoid and was used in vaccine development. We set out to establish a new human challenge model and ascertain the S. Typhi (Quailes strain) inoculum required for an attack rate of 60%–75% in typhoid-naive volunteers when ingested with sodium bicarbonate solution. Methods. Groups of healthy consenting adults ingested escalating dose levels of S. Typhi and were closely monitored in an outpatient setting for 2 weeks. Antibiotic treatment was initiated if typhoid diagnosis occurred (temperature ≥38°C sustained ≥12 hours or bacteremia) or at day 14 in those remaining untreated. Results. Two dose levels (103 or 104 colony-forming units) were required to achieve the primary objective, resulting in attack rates of 55% (11/20) or 65% (13/20), respectively. Challenge was well tolerated; 4 of 40 participants fulfilled prespecified criteria for severe infection. Most diagnoses (87.5%) were confirmed by blood culture, and asymptomatic bacteremia and stool shedding of S. Typhi was also observed. Participants who developed typhoid infection demonstrated serological responses to flagellin and lipopolysaccharide antigens by day 14; however, no anti-Vi antibody responses were detected. Conclusions. Human challenge with a small inoculum of virulent S. Typhi administered in bicarbonate solution can be performed safely using an ambulant-model design to advance understanding of host–pathogen interactions and immunity. This model should expedite development of diagnostics, vaccines, and therapeutics for typhoid control. PMID:24519873

Global MLST of Salmonella Typhi Revisited in Post-genomic Era: Genetic Conservation, Population Structure, and Comparative Genomics of Rare Sequence Types.

PubMed

Yap, Kien-Pong; Ho, Wing S; Gan, Han M; Chai, Lay C; Thong, Kwai L

2016-01-01

Typhoid fever, caused by Salmonella enterica serovar Typhi, remains an important public health burden in Southeast Asia and other endemic countries. Various genotyping methods have been applied to study the genetic variations of this human-restricted pathogen. Multilocus sequence typing (MLST) is one of the widely accepted methods, and recently, there is a growing interest in the re-application of MLST in the post-genomic era. In this study, we provide the global MLST distribution of S. Typhi utilizing both publicly available 1,826 S. Typhi genome sequences in addition to performing conventional MLST on S. Typhi strains isolated from various endemic regions spanning over a century. Our global MLST analysis confirms the predominance of two sequence types (ST1 and ST2) co-existing in the endemic regions. Interestingly, S. Typhi strains with ST8 are currently confined within the African continent. Comparative genomic analyses of ST8 and other rare STs with genomes of ST1/ST2 revealed unique mutations in important virulence genes such as flhB, sipC, and tviD that may explain the variations that differentiate between seemingly successful (widespread) and unsuccessful (poor dissemination) S. Typhi populations. Large scale whole-genome phylogeny demonstrated evidence of phylogeographical structuring and showed that ST8 may have diverged from the earlier ancestral population of ST1 and ST2, which later lost some of its fitness advantages, leading to poor worldwide dissemination. In response to the unprecedented increase in genomic data, this study demonstrates and highlights the utility of large-scale genome-based MLST as a quick and effective approach to narrow the scope of in-depth comparative genomic analysis and consequently provide new insights into the fine scale of pathogen evolution and population structure.

A Salmonella Typhimurium-Typhi Genomic Chimera: A Model to Study Vi Polysaccharide Capsule Function In Vivo

PubMed Central

Clare, Simon; Goulding, David; Holt, Kathryn E.; Grant, Andrew J.; Mastroeni, Piero; Dougan, Gordon; Kingsley, Robert A.

2011-01-01

The Vi capsular polysaccharide is a virulence-associated factor expressed by Salmonella enterica serotype Typhi but absent from virtually all other Salmonella serotypes. In order to study this determinant in vivo, we characterised a Vi-positive S. Typhimurium (C5.507 Vi+), harbouring the Salmonella pathogenicity island (SPI)-7, which encodes the Vi locus. S. Typhimurium C5.507 Vi+ colonised and persisted in mice at similar levels compared to the parent strain, S. Typhimurium C5. However, the innate immune response to infection with C5.507 Vi+ and SGB1, an isogenic derivative not expressing Vi, differed markedly. Infection with C5.507 Vi+ resulted in a significant reduction in cellular trafficking of innate immune cells, including PMN and NK cells, compared to SGB1 Vi− infected animals. C5.507 Vi+ infection stimulated reduced numbers of TNF-α, MIP-2 and perforin producing cells compared to SGB1 Vi−. The modulating effect associated with Vi was not observed in MyD88−/− and was reduced in TLR4−/− mice. The presence of the Vi capsule also correlated with induction of the anti-inflammatory cytokine IL-10 in vivo, a factor that impacted on chemotaxis and the activation of immune cells in vitro. PMID:21829346

Phylogeographical analysis of the dominant multidrug-resistant H58 clade of Salmonella Typhi identifies inter- and intracontinental transmission events.

PubMed

Wong, Vanessa K; Baker, Stephen; Pickard, Derek J; Parkhill, Julian; Page, Andrew J; Feasey, Nicholas A; Kingsley, Robert A; Thomson, Nicholas R; Keane, Jacqueline A; Weill, François-Xavier; Edwards, David J; Hawkey, Jane; Harris, Simon R; Mather, Alison E; Cain, Amy K; Hadfield, James; Hart, Peter J; Thieu, Nga Tran Vu; Klemm, Elizabeth J; Glinos, Dafni A; Breiman, Robert F; Watson, Conall H; Kariuki, Samuel; Gordon, Melita A; Heyderman, Robert S; Okoro, Chinyere; Jacobs, Jan; Lunguya, Octavie; Edmunds, W John; Msefula, Chisomo; Chabalgoity, Jose A; Kama, Mike; Jenkins, Kylie; Dutta, Shanta; Marks, Florian; Campos, Josefina; Thompson, Corinne; Obaro, Stephen; MacLennan, Calman A; Dolecek, Christiane; Keddy, Karen H; Smith, Anthony M; Parry, Christopher M; Karkey, Abhilasha; Mulholland, E Kim; Campbell, James I; Dongol, Sabina; Basnyat, Buddha; Dufour, Muriel; Bandaranayake, Don; Naseri, Take Toleafoa; Singh, Shalini Pravin; Hatta, Mochammad; Newton, Paul; Onsare, Robert S; Isaia, Lupeoletalalei; Dance, David; Davong, Viengmon; Thwaites, Guy; Wijedoru, Lalith; Crump, John A; De Pinna, Elizabeth; Nair, Satheesh; Nilles, Eric J; Thanh, Duy Pham; Turner, Paul; Soeng, Sona; Valcanis, Mary; Powling, Joan; Dimovski, Karolina; Hogg, Geoff; Farrar, Jeremy; Holt, Kathryn E; Dougan, Gordon

2015-06-01

The emergence of multidrug-resistant (MDR) typhoid is a major global health threat affecting many countries where the disease is endemic. Here whole-genome sequence analysis of 1,832 Salmonella enterica serovar Typhi (S. Typhi) identifies a single dominant MDR lineage, H58, that has emerged and spread throughout Asia and Africa over the last 30 years. Our analysis identifies numerous transmissions of H58, including multiple transfers from Asia to Africa and an ongoing, unrecognized MDR epidemic within Africa itself. Notably, our analysis indicates that H58 lineages are displacing antibiotic-sensitive isolates, transforming the global population structure of this pathogen. H58 isolates can harbor a complex MDR element residing either on transmissible IncHI1 plasmids or within multiple chromosomal integration sites. We also identify new mutations that define the H58 lineage. This phylogeographical analysis provides a framework to facilitate global management of MDR typhoid and is applicable to similar MDR lineages emerging in other bacterial species.

Phylogeographical analysis of the dominant multidrug-resistant H58 clade of Salmonella Typhi identifies inter- and intracontinental transmission events

PubMed Central

Wong, Vanessa K; Baker, Stephen; Pickard, Derek J; Parkhill, Julian; Page, Andrew J; Feasey, Nicholas A; Kingsley, Robert A; Thomson, Nicholas R; Keane, Jacqueline A; Weill, François-Xavier; Edwards, David J; Hawkey, Jane; Harris, Simon R; Mather, Alison E; Cain, Amy K; Hadfield, James; Hart, Peter J; Thieu, Nga Tran Vu; Klemm, Elizabeth J; Glinos, Dafni A; Breiman, Robert F; Watson, Conall H; Kariuki, Samuel; Gordon, Melita A; Heyderman, Robert S; Okoro, Chinyere; Jacobs, Jan; Lunguya, Octavie; Edmunds, W John; Msefula, Chisomo; Chabalgoity, Jose A; Kama, Mike; Jenkins, Kylie; Dutta, Shanta; Marks, Florian; Campos, Josefina; Thompson, Corinne; Obaro, Stephen; MacLennan, Calman A; Dolecek, Christiane; Keddy, Karen H; Smith, Anthony M; Parry, Christopher M; Karkey, Abhilasha; Mulholland, E Kim; Campbell, James I; Dongol, Sabina; Basnyat, Buddha; Dufour, Muriel; Bandaranayake, Don; Naseri, Take Toleafoa; Singh, Shalini Pravin; Hatta, Mochammad; Newton, Paul; Onsare, Robert S; Isaia, Lupeoletalalei; Dance, David; Davong, Viengmon; Thwaites, Guy; Wijedoru, Lalith; Crump, John A; De Pinna, Elizabeth; Nair, Satheesh; Nilles, Eric J; Thanh, Duy Pham; Turner, Paul; Soeng, Sona; Valcanis, Mary; Powling, Joan; Dimovski, Karolina; Hogg, Geoff; Farrar, Jeremy; Holt, Kathryn E; Dougan, Gordon

2016-01-01

The emergence of multidrug-resistant (MDR) typhoid is a major global health threat affecting many countries where the disease is endemic. Here whole-genome sequence analysis of 1,832 Salmonella enterica serovar Typhi (S. Typhi) identifies a single dominant MDR lineage, H58, that has emerged and spread throughout Asia and Africa over the last 30 years. Our analysis identifies numerous transmissions of H58, including multiple transfers from Asia to Africa and an ongoing, unrecognized MDR epidemic within Africa itself. Notably, our analysis indicates that H58 lineages are displacing antibiotic-sensitive isolates, transforming the global population structure of this pathogen. H58 isolates can harbor a complex MDR element residing either on transmissible IncHI1 plasmids or within multiple chromosomal integration sites. We also identify new mutations that define the H58 lineage. This phylogeographical analysis provides a framework to facilitate global management of MDR typhoid and is applicable to similar MDR lineages emerging in other bacterial species. PMID:25961941

Epidemic typhoid in Chile: analysis by molecular and conventional methods of Salmonella typhi strain diversity in epidemic (1977 and 1981) and nonepidemic (1990) years.

PubMed

Fica, A E; Prat-Miranda, S; Fernandez-Ricci, A; D'Ottone, K; Cabello, F C

1996-07-01

From 1977 to 1986, Chile experienced an important typhoid fever epidemic, despite statistics that indicated apparently improving levels of sanitation of drinking water and sewage disposal. The lack of antibiotic resistance among the Salmonella typhi strains isolated during this period, the mild clinical presentation of the disease, and the initially low level of efficacy of the S. typhi Ty21a vaccine in the population exposed to the epidemic suggested that this epidemic might have resulted from the dissemination of S. typhi strains with unique characteristics. To investigate this hypothesis, we used conventional methods (bacteriophage typing and biotyping) and molecular methods (restriction fragment length polymorphism analysis, ribotyping, IS200 typing, and PCR amplification of the fliC-d gene) to study a population of 149 S. typhi isolates during 1977, 1981, and 1990, the years that included periods with low (when the disease was endemic) and high (when the disease was epidemic) morbidities. Our results indicate that these S. typhi isolates in Chile represent a number of highly diverse variants of the clone of S. typhi with a worldwide distribution described by Selander et al. (R. K. Selander, P. Beltran, N.H. Smith, R. Helmuth, F.A. Rubin, D.J. Kopecko, K. Ferris, B.D. Tall, A. Cravioto, and J.M. Musser, Infect. Immun. 58:2262-2275, 1990). For example, we detected 26 PstI and 10 ClaI ribotypes among 47 and 16 S. typhi strains belonging to this clone, respectively. These results suggest that the Chilean epidemic was probably produced by multiple sources of infection because of deficient sanitary conditions. These findings illustrate the usefulness of molecular methods for characterizing the potential causes of the typhoid epidemics and the possible routes of transmission of S. typhi strains in typhoid epidemics.

Epidemic typhoid in Chile: analysis by molecular and conventional methods of Salmonella typhi strain diversity in epidemic (1977 and 1981) and nonepidemic (1990) years.

PubMed Central

Fica, A E; Prat-Miranda, S; Fernandez-Ricci, A; D'Ottone, K; Cabello, F C

1996-01-01

From 1977 to 1986, Chile experienced an important typhoid fever epidemic, despite statistics that indicated apparently improving levels of sanitation of drinking water and sewage disposal. The lack of antibiotic resistance among the Salmonella typhi strains isolated during this period, the mild clinical presentation of the disease, and the initially low level of efficacy of the S. typhi Ty21a vaccine in the population exposed to the epidemic suggested that this epidemic might have resulted from the dissemination of S. typhi strains with unique characteristics. To investigate this hypothesis, we used conventional methods (bacteriophage typing and biotyping) and molecular methods (restriction fragment length polymorphism analysis, ribotyping, IS200 typing, and PCR amplification of the fliC-d gene) to study a population of 149 S. typhi isolates during 1977, 1981, and 1990, the years that included periods with low (when the disease was endemic) and high (when the disease was epidemic) morbidities. Our results indicate that these S. typhi isolates in Chile represent a number of highly diverse variants of the clone of S. typhi with a worldwide distribution described by Selander et al. (R. K. Selander, P. Beltran, N.H. Smith, R. Helmuth, F.A. Rubin, D.J. Kopecko, K. Ferris, B.D. Tall, A. Cravioto, and J.M. Musser, Infect. Immun. 58:2262-2275, 1990). For example, we detected 26 PstI and 10 ClaI ribotypes among 47 and 16 S. typhi strains belonging to this clone, respectively. These results suggest that the Chilean epidemic was probably produced by multiple sources of infection because of deficient sanitary conditions. These findings illustrate the usefulness of molecular methods for characterizing the potential causes of the typhoid epidemics and the possible routes of transmission of S. typhi strains in typhoid epidemics. PMID:8784573

Further consideration of the clonal nature of Salmonella typhi: evaluation of molecular and clinical characteristics of strains from Indonesia and Peru.

PubMed Central

Franco, A; Gonzalez, C; Levine, O S; Lagos, R; Hall, R H; Hoffman, S L; Moechtar, M A; Gotuzzo, E; Levine, M M; Hone, D M

1992-01-01

We examined envelope protein profiles, chromosomal restriction endonuclease digest patterns, and immune responses to envelope proteins for collections of Salmonella typhi strains isolated in Peru and Indonesia. Only minor differences in envelope protein patterns were apparent among strains. Strains from 7 of 20 Indonesian patients had a distinct chromosomal digest pattern compared with patterns of Peruvian and other Indonesian strains. Strains with this pattern carried the gene for the j flagellar antigen (H1-j); differences in response to envelope proteins of j and d strains were noted on immunoblot analysis. Our data suggest that there are genotypic and phenotypic differences among S. typhi strains. The clinical importance of these differences remains to be fully evaluated; however, in this study it was not possible to show a clear correlation between strain characteristics and disease severity. Images PMID:1500532

Structural Basis of Typhoid: Salmonella typhi Type IVb pilin (PilS) and Cystic Fibrosis Transmembrane Conductance Regulatory Interaction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Balakrishna, A.; Saxena, A; Mok, H

2009-01-01

The type IVb pilus of the enteropathogenic bacteria Salmonella typhi is a major adhesion factor during the entry of this pathogen into gastrointestinal epithelial cells. Its target of adhesion is a stretch of 10 residues from the first extracellular domain of cystic fibrosis transmembrane conductance regulator (CFTR). The crystal structure of the N-terminal 25 amino acid deleted S. typhi native PilS protein (PilS), which makes the pilus, was determined at 1.9 A resolution by the multiwavelength anomalous dispersion method. Also, the structure of the complex of PilS and a target CFTR peptide, determined at 1.8 A, confirms that residues 113-117more » (NKEER) of CFTR are involved in binding with the pilin protein and gives us insight on the amino acids that are essential for binding. Furthermore, we have also explored the role of a conserved disulfide bridge in pilus formation. The subunit structure and assembly architecture are crucial for understanding pilus functions and designing suitable therapeutics against typhoid.« less

Structural basis of typhod: Salmonella typhi type IVb pilin (PilS) and cystic fibrosis transmembrane conductance regulator interaction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Balakrishna, A.; Saxena, A; Mok, H

2009-01-01

The type IVb pilus of the enteropathogenic bacteria Salmonella typhi is a major adhesion factor during the entry of this pathogen into gastrointestinal epithelial cells. Its target of adhesion is a stretch of 10 residues from the first extracellular domain of cystic fibrosis transmembrane conductance regulator (CFTR). The crystal structure of the N-terminal 25 amino acid deleted S. typhi native PilS protein (PilS), which makes the pilus, was determined at 1.9 A resolution by the multiwavelength anomalous dispersion method. Also, the structure of the complex of PilS and a target CFTR peptide, determined at 1.8 A, confirms that residues 113-117more » (NKEER) of CFTR are involved in binding with the pilin protein and gives us insight on the amino acids that are essential for binding. Furthermore, we have also explored the role of a conserved disulfide bridge in pilus formation. The subunit structure and assembly architecture are crucial for understanding pilus functions and designing suitable therapeutics against typhoid.« less

Comparative genomics of closely related Salmonella enterica serovar Typhi strains reveals genome dynamics and the acquisition of novel pathogenic elements.

PubMed

Yap, Kien-Pong; Gan, Han Ming; Teh, Cindy Shuan Ju; Chai, Lay Ching; Thong, Kwai Lin

2014-11-20

Typhoid fever is an infectious disease of global importance that is caused by Salmonella enterica subsp. enterica serovar Typhi (S. Typhi). This disease causes an estimated 200,000 deaths per year and remains a serious global health threat. S. Typhi is strictly a human pathogen, and some recovered individuals become long-term carriers who continue to shed the bacteria in their faeces, thus becoming main reservoirs of infection. A comparative genomics analysis combined with a phylogenomic analysis revealed that the strains from the outbreak and carrier were closely related with microvariations and possibly derived from a common ancestor. Additionally, the comparative genomics analysis with all of the other completely sequenced S. Typhi genomes revealed that strains BL196 and CR0044 exhibit unusual genomic variations despite S. Typhi being generally regarded as highly clonal. The two genomes shared distinct chromosomal architectures and uncommon genome features; notably, the presence of a ~10 kb novel genomic island containing uncharacterised virulence-related genes, and zot in particular. Variations were also detected in the T6SS system and genes that were related to SPI-10, insertion sequences, CRISPRs and nsSNPs among the studied genomes. Interestingly, the carrier strain CR0044 harboured far more genetic polymorphisms (83% mutant nsSNPs) compared with the closely related BL196 outbreak strain. Notably, the two highly related virulence-determinant genes, rpoS and tviE, were mutated in strains BL196 and CR0044, respectively, which revealed that the mutation in rpoS is stabilising, while that in tviE is destabilising. These microvariations provide novel insight into the optimisation of genes by the pathogens. However, the sporadic strain was found to be far more conserved compared with the others. The uncommon genomic variations in the two closely related BL196 and CR0044 strains suggests that S. Typhi is more diverse than previously thought. Our study has

Revised Ciprofloxacin Breakpoints for Salmonella: Is it Time to Write an Obituary?

PubMed

Girish, Revathy; Kumar, Anil; Khan, Sadia; Dinesh, Kavitha R; Karim, Shamsul

2013-11-01

To determine the minimum inhibitory concentration of ciprofloxacin among 50 blood stream isolates of Salmonella enterica. A total of 50 consecutive isolates of Salmonella enterica were tested for susceptibility to antimicrobials using the Kirby Bauer disk diffusion method. Minimum inhibitory concentrations were determined using Hi-Comb strips. All results were interpreted according to the CLSI guidelines. Of the 50 isolates 70%were Salmonella Typhi, 4% Salmonella paratyphi A, 2% Salmonella paratyphi B and the remaining 10% were identified only as Salmonella species. Using the CLSI 2011 breakpoints for disc diffusion, 86% (43/50) were resistant to nalidixic acid(NA), 22% (11/50) to ciprofloxacin, 12% to azithromycin, 6% to cotrimoxazole, 4% to ampicillin and 1% to chloramphenicol. The MIC50 and MIC90 of ciprofloxacin for S.Typhi were 0.181 μg/mL and 5.06 μg/mL respectively. While the same for S. paratyphi A was 0.212μg/mL and 0.228μg/mL respectively. None of the isolates were multi drug resistant and all were susceptible to ceftriaxone. Using the CLSI 2012 revised ciprofloxacin breakpoints for disc diffusion (>31mm) & MIC (<0.06 μg/mL), 90% (45/50) of these isolates were found to be resistant. MIC's of ciprofloxacin should be reported for all salmonella isolates and should be used to guide treatment. Blindly following western guidelines for a disease which is highly endemic in the subcontinent will spell the death knell of a cheap and effective drug in our armamentarium. Therefore it will be too premature to declare that "the concept of using ciprofloxacin in typhoid fever is dead!"

Compositional and Functional Differences in the Human Gut Microbiome Correlate with Clinical Outcome following Infection with Wild-Type Salmonella enterica Serovar Typhi

PubMed Central

Zhang, Yan; Brady, Arthur; Jones, Cheron; Song, Yang; Darton, Thomas C.; Jones, Claire; Blohmke, Christoph J.; Pollard, Andrew J.; Magder, Laurence S.; Fasano, Alessio; Sztein, Marcelo B.

2018-01-01

ABSTRACT Insights into disease susceptibility as well as the efficacy of vaccines against typhoid and other enteric pathogens may be informed by better understanding the relationship between the effector immune response and the gut microbiota. In the present study, we characterized the composition (16S rRNA gene profiling) and function (RNA sequencing [RNA-seq]) of the gut microbiota following immunization and subsequent exposure to wild-type Salmonella enterica serovar Typhi in a human challenge model to further investigate the central hypothesis that clinical outcomes may be linked to the gut microbiota. Metatranscriptome analysis of longitudinal stool samples collected from study subjects revealed two stable patterns of gene expression for the human gut microbiota, dominated by transcripts from either Methanobrevibacter or a diverse representation of genera in the Firmicutes phylum. Immunization with one of two live oral attenuated vaccines against S. Typhi had minimal effects on the composition or function of the gut microbiota. It was observed that subjects harboring the methanogen-dominated transcriptome community at baseline displayed a lower risk of developing symptoms of typhoid following challenge with wild-type S. Typhi. Furthermore, genes encoding antioxidant proteins, metal homeostasis and transport proteins, and heat shock proteins were expressed at a higher level at baseline or after challenge with S. Typhi in subjects who did not develop symptoms of typhoid. These data suggest that functional differences relating to redox potential and ion homeostasis in the gut microbiota may impact clinical outcomes following exposure to wild-type S. Typhi. PMID:29739901

An Unmutated IgM Response to the Vi Polysaccharide of Salmonella Typhi Contributes to Protective Immunity in a Murine Model of Typhoid.

PubMed

Pandya, Kalgi D; Palomo-Caturla, Isabel; Walker, Justin A; K Sandilya, Vijay; Zhong, Zhijiu; Alugupalli, Kishore R

2018-06-15

T cell-dependent B cell responses typically develop in germinal centers. Abs generated during such responses are isotype switched and have a high affinity to the Ag because of somatic hypermutation of Ab genes. B cell responses to purified polysaccharides are T cell independent and do not result in the formation of bona fide germinal centers, and the dominant Ab isotype produced during such responses is IgM with very few or no somatic mutations. Activation-induced cytidine deaminase (AID) is required for both somatic hypermutation and Ig isotype switching in humans and mice. To test the extent to which unmutated polysaccharide-specific IgM confers protective immunity, we immunized wildtype and AID -/- mice with either heat-killed Salmonella enterica serovar Typhi ( S. Typhi) or purified Vi polysaccharide (ViPS). We found that wildtype and AID -/- mice immunized with heat-killed S. Typhi generated similar anti-ViPS IgM responses. As expected, wildtype, but not AID -/- mice generated ViPS-specific IgG. However, the differences in the Ab-dependent killing of S. Typhi mediated by the classical pathway of complement activation were not statistically significant. In ViPS-immunized wildtype and AID -/- mice, the ViPS-specific IgM levels and S. Typhi bactericidal Ab titers at 7 but not at 28 d postimmunization were also comparable. To test the protective immunity conferred by these immunizations, mice were challenged with a chimeric S. Typhimurium strain expressing ViPS. Compared with their naive counterparts, immunized wildtype and AID -/- mice exhibited significantly reduced bacterial burden regardless of the route of infection. These data indicate that an unmutated IgM response to ViPS contributes to protective immunity to S. Typhi. Copyright © 2018 by The American Association of Immunologists, Inc.

Antimicrobial susceptibility of travel-related Salmonella enterica serovar Typhi isolates detected in Switzerland (2002-2013) and molecular characterization of quinolone resistant isolates.

PubMed

Nüesch-Inderbinen, Magdalena; Abgottspon, Helga; Sägesser, Grethe; Cernela, Nicole; Stephan, Roger

2015-05-12

Typhoid fever is an acute, invasive, and potentially fatal systemic infection caused by Salmonella enterica subspecies enterica serotype Typhi (S. Typhi). Drug resistance to antimicrobials such as ciprofloxacin is emerging in developing countries, threatening the efficacy of treatment of patients in endemic regions as well as of travellers returning from these countries. We compared the antimicrobial resistance profiles of 192 S. Typhi isolated from patients over a time span of twelve years. Susceptibility testing was done by the disk diffusion method. A representative selection of isolates (n = 41) was screened by PCR for mutations in the quinolone resistance-determining regions (QRDRs) of the gyrA and parC genes and all 192 isolates were screened for plasmid-mediated quinolone resistance (PMQR) genes. Multilocus sequence typing (MLST) was used to investigate the sequence type of isolates from patients with a known history of international travel. Resistance rates for nalidixic acid increased from 20 % to 66.7 % between 2002 and 2013. Resistance to ciprofloxacin was detected in 55.6 % of the isolates by 2013. Ciprofloxacin resistance was predominantly associated with the triple substitutions Ser83 → Phe and Asp87 → Asn in GyrA and Ser80 → Ile in ParC. The plasmid-mediated resistance gene qnrS1 was detected in two isolates. Sequence type ST1 was associated with the Indian subcontinent, while ST2 was distributed internationally. Multidrug resistance was noted for 11.5 % of the isolates. Fluoroquinolone resistant S. Typhi constitute a serious public health concern in endemic areas as well as in industrialized countries. Increased surveillance of global patterns of antimicrobial resistance is necessary and the control of resistant strains is of the utmost importance to maintain treatment options.

The Influence of Reduced Susceptibility to Fluoroquinolones in Salmonella enterica Serovar Typhi on the Clinical Response to Ofloxacin Therapy

PubMed Central

Parry, Christopher M.; Vinh, Ha; Chinh, Nguyen Tran; Wain, John; Campbell, James I.; Hien, Tran Tinh; Farrar, Jeremy J.; Baker, Stephen

2011-01-01

Background Infection with Salmonella enterica serovar Typhi (S. Typhi) with reduced susceptibility to fluoroquinolones has been associated with fluoroquinolone treatment failure. We studied the relationship between ofloxacin treatment response and the ofloxacin minimum inhibitory concentration (MIC) of the infecting isolate. Individual patient data from seven randomised controlled trials of antimicrobial treatment in enteric fever conducted in Vietnam in which ofloxacin was used in at least one of the treatment arms was studied. Data from 540 patients randomised to ofloxacin treatment was analysed to identify an MIC of the infecting organism associated with treatment failure. Principal Findings The proportion of patients failing ofloxacin treatment was significantly higher in patients infected with S. Typhi isolates with an MIC≥0.25 µg/mL compared with those infections with an MIC of ≤0.125 µg/mL (p<0.001). Treatment success was 96% when the ofloxacin MIC was ≤0.125 µg/mL, 73% when the MIC was between 0.25 and 0.50 µg/mL and 53% when the MIC was 1.00 µg/mL. This was despite a longer duration of treatment at a higher dosage in patients infected with isolates with an MIC≥0.25 µg/mL compared with those infections with an MIC of ≤0.125 µg/mL. Significance There is a clear relationship between ofloxacin susceptibility and clinical outcome in ofloxacin treated patients with enteric fever. An ofloxacin MIC of ≥0.25 µg/mL, or the presence of nalidixic acid resistance, can be used to define S. Typhi infections in which the response to ofloxacin may be impaired. PMID:21713025

Serological response following re-vaccination with Salmonella typhi Vi-capsular polysaccharide vaccines in healthy adult travellers.

PubMed

Roggelin, Louise; Vinnemeier, Christof D; Fischer-Herr, Johanna; Johnson-Weaver, Brandi T; Rolling, Thierry; Burchard, Gerd D; Staats, Herman F; Cramer, Jakob P

2015-08-07

An injectable Vi-capsular polysaccharide vaccine against typhoid fever is available but vaccine-induced immunity tends to wane over time. The phenomenon of immunotolerance or hyporesponsiveness has earlier been described for polysaccharide vaccines such as pneumococcal capsular polysaccharide vaccine and some publications also suggest a possible immunotolerance after revaccination with Vi-capsular polysaccharide vaccines. In this study, post-immunisation antibody concentrations in adult travellers first vaccinated with a Salmonella typhi Vi-capsular polysaccharide vaccine (primary vaccination group) were compared with those having received one or more vaccinations previously (multiple vaccinations group). Vaccines administered were Typherix(®) (GlaxoSmithKline), Typhim Vi(®) (Sanofi Pasteur MSD) or Hepatyrix(®) (GlaxoSmithKline). Blood samples were obtained prior to vaccination (day 0) and on day 28 (-1/+14) after vaccination. Serum Vi-Antigen IgG concentrations were measured by ELISA. Of the 85 subjects included in the per protocol data set, 45 (53%) belonged to the multiple vaccinations group. In both groups, geometric mean antibody concentrations (GMCs) were significantly higher after vaccination than before vaccination. Pre-vaccination GMCs were lower in the primary vaccination group than in the multiple vaccinations group (3.40 μg/ml versus 6.13 μg/ml, P=0.005), while there was no significant difference in the post vaccination GMCs between groups (11.34 μg/ml versus 14.58 μg/ml, P=0.4). In the multiple vaccinations group, vaccination was performed 18 to 57 months after the last vaccination (median 38 months) and there was a negative correlation between time since last vaccination and antibody concentration on day 0. In conclusion, we were not able to demonstrate a relevant immunotolerance after multiple versus primary vaccination with S. typhi Vi-capsular polysaccharide vaccines. Copyright © 2015 Elsevier Ltd. All rights reserved.

An electrochemical genosensor for Salmonella typhi on gold nanoparticles-mercaptosilane modified screen printed electrode.

PubMed

Das, Ritu; Sharma, Mukesh K; Rao, Vepa K; Bhattacharya, B K; Garg, Iti; Venkatesh, V; Upadhyay, Sanjay

2014-10-20

In this work, we fabricated a system of integrated self-assembled layer of organosilane 3-mercaptopropyltrimethoxy silane (MPTS) on the screen printed electrode (SPE) and electrochemically deposited gold nanoparticle for Salmonella typhi detection employing Vi gene as a molecular marker. Thiolated DNA probe was immobilized on a gold nanoparticle (AuNP) modified SPE for DNA hybridization assay using methylene blue as redox (electroactive) hybridization indicator, and signal was monitored by differential pulse voltammetry (DPV) method. The modified SPE was characterized by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and atomic force microscopy (AFM) method. The DNA biosensor showed excellent performances with high sensitivity and good selectivity. The current response was linear with the target sequence concentrations ranging from 1.0 × 10(-11) to 0.5 × 10(-8)M and the detection limit was found to be 50 (± 2.1)pM. The DNA biosensor showed good discrimination ability to the one-base, two-base and three-base mismatched sequences. The fabricated genosensor could also be regenerated easily and reused for three to four times for further hybridization studies. Copyright © 2014 Elsevier B.V. All rights reserved.

[About problems of carriers of Salmonella typhi and paratyphi B under hygienic, epidemiologic and sociologic view (authors transl)].

PubMed

Brossmann, D

1977-01-01

The carriers of salmonella typhi and paratyphi B are the central figures of the epidemiology of typhoid illnesses. The files available at the medical authorities' office of the Hansestadt Lübeck, with regards to all 543 carriers registered up to 1972, have been analysed, and 102 of 108 carriers who were inhabitants of Lübeck on 31.10.72, have been interviewed in their lodgings.--Following results are mentionable: 1. 55 carriers have been traced during a hospital stay, 22 of them were under hospital treatment because of cholecystectomy. 2. The circle of persons to be obligated for medical examination as per $ 17 of the Federal Republic of Germany's law of epidemics has proved as too small. For instance two female carriers--known since years--did their job without any hindering as plates washer or waitress in restaurants. 3. 21 persons=4% of the patients excreted salmonellae in urine only. 4. 10% of the carriers of salmonella typhi and 16% of the carriers of salmonella paratypi B had in their faeces as least 5-years intervals of non-excretion. 5. The precentage of carriers with at least 5-years intervals of non-excretion in urine was significantly larger than the corresponding percentage in faeces. 6. Falling ill of 280 persons out of the environs of the carriers have been lead back to the latters. 73% of these infections were placed by the carriers before their detection through the medical authorities' office. 7. For 10 patients whose health was recreated excretion did not cease promptly after the cholecystecystectomy. Salmonellae had been found in the faeces for several months more, at two persons even two years after the operation. 8. For 8 carriers a final decision with regards to the success of cholecystectomy is impossible because they denied a duodenal soundation. 9. 123 persons of 23% of total 543 carriers had--before their ascertation--professions not allowed for those persons. Efforts for a successful job arrangement, possibly combined with a change in

Multi-drug resistance and reduced susceptibility to ciprofloxacin among Salmonella enterica serovar Typhi isolates from the Middle East and Central Asia.

PubMed

Rahman, B A; Wasfy, M O; Maksoud, M A; Hanna, N; Dueger, E; House, B

2014-07-01

Typhoid fever is common in developing countries, with an estimated 120 million infections and 700 000 annual deaths, worldwide. Fluoroquinolones have been the treatment of choice for infection with multidrug-resistant (MDR) Salmonella enterica serovar Typhi (S. Typhi). However, alarming reports of fluoroquinolone-resistance and failure of typhoid fever treatment have recently been published. To determine the proportion of S. Typhi isolates with reduced susceptibility to ciprofloxacin (RSC) from six countries in the Middle East and Central Asia, 968 S. Typhi isolates collected between 2002 and 2007 from Egypt, Uzbekistan, Pakistan, Qatar, Jordan and Iraq were tested for antibiotic susceptibility to five antibiotics using the disc-diffusion method. MDR was defined as resistance to amicillin, chloramphenicol and trimethoprim-sulfamethoxazole. The E-test was employed to determine the MIC of ciprofloxacin only. Nalidixic acid resistance was evaluated as a marker for RSC. Interpretations were made according to CLSI guidelines. MDR strains were considerably more prevalent in Iraq (83%) and Pakistan (52%) compared with the other countries studied (13-52%). Nearly all isolates were susceptible (99.7%) to ceftriaxone. RSC was detected in a total of 218 isolates (22%), mostly from Iraq (54/59, 92%), Uzbekistan (98/123, 80%), Qatar (23/43, 54%) and Pakistan (31/65, 47%). Many of these (21%) were also MDR. Use of nalidixic acid resistance as an indicator for RSC was 99% sensitive and 98% specific. This study reinforces the need for routine antimicrobial susceptibility surveillance of enteric fever isolates and close review of current therapeutic policies in the region.

Antimicrobial Susceptibility to Azithromycin among Salmonella enterica Isolates from the United States▿

PubMed Central

Sjölund-Karlsson, Maria; Joyce, Kevin; Blickenstaff, Karen; Ball, Takiyah; Haro, Jovita; Medalla, Felicita M.; Fedorka-Cray, Paula; Zhao, Shaohua; Crump, John A.; Whichard, Jean M.

2011-01-01

Due to emerging resistance to traditional antimicrobial agents, such as ampicillin, trimethoprim-sulfamethoxazole, and chloramphenicol, azithromycin is increasingly used for the treatment of invasive Salmonella infections. In the present study, 696 isolates of non-Typhi Salmonella collected from humans, food animals, and retail meats in the United States were investigated for antimicrobial susceptibility to azithromycin. Seventy-two Salmonella enterica serotype Typhi isolates from humans were also tested. For each isolate, MICs of azithromycin and 15 other antimicrobial agents were determined by broth microdilution. Among the non-Typhi Salmonella isolates, azithromycin MICs among human isolates ranged from 1 to 32 μg/ml, whereas the MICs among the animal and retail meat isolates ranged from 2 to 16 μg/ml and 4 to 16 μg/ml, respectively. Among Salmonella serotype Typhi isolates, the azithromycin MICs ranged from 4 to 16 μg/ml. The highest MIC observed in the present study was 32 μg/ml, and it was detected in three human isolates belonging to serotypes Kentucky, Montevideo, and Paratyphi A. Based on our findings, we propose an epidemiological cutoff value (ECOFF) for wild-type Salmonella of ≤16 μg/ml of azithromycin. The susceptibility data provided could be used in combination with clinical outcome data to determine tentative clinical breakpoints for azithromycin and Salmonella enterica. PMID:21690279

Salmonella Infections in Childhood.

PubMed

Bula-Rudas, Fernando J; Rathore, Mobeen H; Maraqa, Nizar F

2015-08-01

Salmonella are gram-negative bacilli within the family Enterobacteriaceae. They are the cause of significant morbidity and mortality worldwide. Animals (pets) are an important reservoir for nontyphoidal Salmonella, whereas humans are the only natural host and reservoir for Salmonella Typhi. Salmonella infections are a major cause of gastroenteritis worldwide. They account for an estimated 2.8 billion cases of diarrheal disease each year. The transmission of Salmonella is frequently associated with the consumption of contaminated water and food of animal origin, and it is facilitated by conditions of poor hygiene. Nontyphoidal Salmonella infections have a worldwide distribution, whereas most typhoidal Salmonella infections in the United States are acquired abroad. In the United States, Salmonella is a common agent for food-borne–associated infections. Several outbreaks have been identified and are most commonly associated with agricultural products. Nontyphoidal Salmonella infection is usually characterized by a self-limited gastroenteritis in immunocompetent hosts in industrialized countries, but it may also cause invasive disease in vulnerable individuals (eg, children less than 1 year of age, immunocompromised). Antibiotic treatment is not recommended for treatment of mild to moderate gastroenteritis by nontyphoidal Salmonella in immunocompetent adults or children more than 1 year of age. Antibiotic treatment is recommended for nontyphoidal Salmonella infections in infants less than 3 months of age, because they are at higher risk for bacteremia and extraintestinal complications. Typhoid (enteric) fever and its potential complications have a significant impact on children, especially those who live in developing countries. Antibiotic treatment of typhoid fever has become challenging because of the emergence of Salmonella Typhi strains that are resistant to classically used first-line agents: ampicillin, trimethoprim-sulfamethoxazole, and chloramphenicol. The

Investigating the decay rates of Escherichia coli relative to Vibrio parahemolyticus and Salmonella Typhi in tropical coastal waters.

PubMed

Lee, Choon Weng; Ng, Angie Yee Fang; Bong, Chui Wei; Narayanan, Kumaran; Sim, Edmund Ui Hang; Ng, Ching Ching

2011-02-01

Using the size fractionation method, we measured the decay rates of Escherichia coli, Salmonella Typhi and Vibrio parahaemolyticus in the coastal waters of Peninsular Malaysia. The size fractions were total or unfiltered, <250 μm, <20 μm, <2 μm, <0.7 μm, <0.2 μm and <0.02 μm. We also carried out abiotic (inorganic nutrients) and biotic (bacterial abundance, production and protistan bacterivory) measurements at Port Dickson, Klang and Kuantan. Klang had highest nutrient concentrations whereas both bacterial production and protistan bacterivory rates were highest at Kuantan. We observed signs of protist-bacteria coupling via the following correlations: Protistan bacterivory-Bacterial Production: r = 0.773, df = 11, p < 0.01; Protist-Bacteria: r = 0.586, df = 12, p < 0.05. However none of the bacterial decay rates were correlated with the biotic variables measured. E. coli and Salmonella decay rates were generally higher in the larger fraction (>0.7 μm) than in the smaller fraction (<0.7 μm) suggesting the more important role played by protists. E. coli and Salmonella also decreased in the <0.02 μm fraction and suggested that these non-halophilic bacteria did not survive well in seawater. In contrast, Vibrio grew well in seawater. There was usually an increase in Vibrio after one day incubation. Our results confirmed that decay or loss rates of E. coli did not match that of Vibrio, and also did not correlate with Salmonella decay rates. However E. coli showed persistence where its decay rates were generally lower than Salmonella. © 2010 Elsevier Ltd. All rights reserved.

DNA biosensor for detection of Salmonella typhi from blood sample of typhoid fever patient using gold electrode modified by self-assembled monolayers of thiols

NASA Astrophysics Data System (ADS)

Suryapratiwi, Windha Novita; Paat, Vlagia Indira; Gaffar, Shabarni; Hartati, Yeni Wahyuni

2017-05-01

Electrochemical biosensors are currently being developed in order to handle various clinical problems in diagnosing infectious diseases caused by pathogenic bacteria, or viruses. On this research, voltammetric DNA biosensor using gold electrode modified by thiols with self-assembled monolayers had been developed to detect a certain sequence of Salmonella typhi DNA from blood sample of typhoid fever patient. Thiol groups of cysteamines (Cys) and aldehyde groups from glutaraldehydes (Glu) were used as a link to increase the performance of gold electrode in detecting guanine oxidation signal of hybridized S. typhi DNA and ssDNA probe. Standard calibration method was used to determine analytical parameters from the measurements. The result shown that, the detection of S. typhi DNA from blood sample of typhoid fever patient can be carried out by voltammetry using gold electrode modified by self-assembled monolayers of thiols. A characteristic oxidation potential of guanine using Au/Cys/Gluwas obtained at +0.17 until +0.20 V. Limit of detection and limit of quantification from this measurements were 1.91μg mL-1 and 6.35 μg mL-1. The concentration of complement DNA from sample was 6.96 μg mL-1.

Restaurant-associated outbreak of Salmonella typhi in Nauru: an epidemiological and cost analysis.

PubMed Central

Olsen, S. J.; Kafoa, B.; Win, N. S.; Jose, M.; Bibb, W.; Luby, S.; Waidubu, G.; O'Leary, M.; Mintz, E.

2001-01-01

Typhoid fever is endemic in the South Pacific. We investigated an outbreak in Nauru. Through interviews and medical records, we identified 50 persons with onset between 1 October 1998 and 10 May 1999, of fever lasting > or = 3 days and one other symptom. Salmonella Typhi was isolated from 19 (38%) cases. Thirty-two (64%) patients were school-aged children, and 17 (34%) were in four households. Case-control studies of (a) culture-confirmed cases and age- and neighbourhood-matched controls; and (b) household index cases and randomly selected age-matched controls implicated two restaurants: Restaurant M (matched OR [MOR] = 11, 95% confidence interval [CI] = 1.3-96) and Restaurant I (MOR = 5.8, 95% CI = 1.2-29). Food-handlers at both restaurants had elevated anti-Vi antibody titres indicative of carrier state. The annual incidence was 5.0/1000 persons. Outbreak-associated costs were $46,000. Routine or emergency immunization campaigns targeting school-aged children may help prevent or control outbreaks of typhoid fever in endemic disease areas. PMID:11811872

Antibacterial activities of Origanum vulgare alone and in combination with different antimicrobials against clinical isolates of Salmonella typhi

PubMed Central

Bharti, Veni; Vasudeva, Neeru; Sharma, Sunil; Duhan, Joginder Singh

2013-01-01

Background: Typhoid fever continues to remain a major public health problem especially in the areas where there is problem of sanitation and hygiene. The emergence of multidrug resistance of Salmonella typhi, the bacteria responsible for Typhoid to ampicillin, chloramphenicol, and cotrimoxazole has further complicated the treatment and management of enteric fever. One strategy for the treatment of the multidrug resistant bacteria is to use herbs in combination with conventional drugs. The present study was done to find out the interaction effect of phenolic, nonphenolic fractions, and volatile oil of Origanum vulgare with ciprofloxacin. Materials and Methods: The minimum inhibitory concentration (MIC) by microdilution method for individual phytoconstituents and in combination with ciprofloxacin was compared for clinically isolated bacteria from patients infected with S. typhi. Fractional inhibitory concentration (FIC) and Fractional inhibitory concentration index (FICI) were also calculated. Results: The MIC declined to a significant level indicating synergistic relationship between ciprofloxacin and phenolic, nonphenolic fractions and volatile oil in vitro. The FICI exhibits synergistic effect for all the three samples while indifferent and antagonistic for samples and for phenolic and nonphenolic fractions. Conclusions: Present study shows that not only the formulation using O. vulgare and ciprofloxacin can overcome multidrug resistance but also will reduce the toxic effects of ciprofloxacin. PMID:24991069

Compositional and Functional Differences in the Human Gut Microbiome Correlate with Clinical Outcome following Infection with Wild-Type Salmonella enterica Serovar Typhi.

PubMed

Zhang, Yan; Brady, Arthur; Jones, Cheron; Song, Yang; Darton, Thomas C; Jones, Claire; Blohmke, Christoph J; Pollard, Andrew J; Magder, Laurence S; Fasano, Alessio; Sztein, Marcelo B; Fraser, Claire M

2018-05-08

Insights into disease susceptibility as well as the efficacy of vaccines against typhoid and other enteric pathogens may be informed by better understanding the relationship between the effector immune response and the gut microbiota. In the present study, we characterized the composition (16S rRNA gene profiling) and function (RNA sequencing [RNA-seq]) of the gut microbiota following immunization and subsequent exposure to wild-type Salmonella enterica serovar Typhi in a human challenge model to further investigate the central hypothesis that clinical outcomes may be linked to the gut microbiota. Metatranscriptome analysis of longitudinal stool samples collected from study subjects revealed two stable patterns of gene expression for the human gut microbiota, dominated by transcripts from either Methanobrevibacter or a diverse representation of genera in the Firmicutes phylum. Immunization with one of two live oral attenuated vaccines against S.  Typhi had minimal effects on the composition or function of the gut microbiota. It was observed that subjects harboring the methanogen-dominated transcriptome community at baseline displayed a lower risk of developing symptoms of typhoid following challenge with wild-type S.  Typhi. Furthermore, genes encoding antioxidant proteins, metal homeostasis and transport proteins, and heat shock proteins were expressed at a higher level at baseline or after challenge with S.  Typhi in subjects who did not develop symptoms of typhoid. These data suggest that functional differences relating to redox potential and ion homeostasis in the gut microbiota may impact clinical outcomes following exposure to wild-type S.  Typhi. IMPORTANCE S.  Typhi is a significant cause of systemic febrile morbidity in settings with poor sanitation and limited access to clean water. It has been demonstrated that the human gut microbiota can influence mucosal immune responses, but there is little information available on the impact of the human gut

Room Temperature Stabilization of Oral, Live Attenuated Salmonella enterica serovar Typhi-Vectored Vaccines

PubMed Central

Ohtake, Satoshi; Martin, Russell; Saxena, Atul; Pham, Binh; Chiueh, Gary; Osorio, Manuel; Kopecko, Dennis; Xu, DeQi; Lechuga-Ballesteros, David; Truong-Le, Vu

2011-01-01

Foam drying, a modified freeze drying process, was utilized to produce a heat-stable, live attenuated Salmonella Typhi ‘Ty21a’ bacterial vaccine. Ty21a vaccine was formulated with pharmaceutically approved stabilizers, including sugars, plasticizers, amino acids, and proteins. Growth media and harvesting conditions of the bacteria were also studied to enhance resistance to desiccation stress encountered during processing as well as subsequent storage at elevated temperatures. The optimized Ty21a vaccine, formulated with trehalose, methionine, and gelatin, demonstrated stability for approximately 12 weeks at 37°C (i.e., time required for the vaccine to decrease in potency by 1log10 CFU) and no loss in titer at 4 and 25°C following storage for the same duration. Furthermore, the foam dried Ty21a elicited a similar immunogenic response in mice as well as protection in challenge studies compared to Vivotif™, the commercial Ty21a vaccine. The enhanced heat stability of the Ty21a oral vaccine, or Ty21a derivatives expressing foreign antigens (e.g. anthrax), could mitigate risks of vaccine potency loss during long term storage, shipping, delivery to geographical areas with warmer climates or during emergency distribution following a bioterrorist attack. Because the foam drying process is conducted using conventional freeze dryers and can be readily implemented at any freeze drying manufacturing facility, this technology appears ready and appropriate for large scale processing of foam dried vaccines. PMID:21300096

Salmonella typhi infection in a tertiary institution in Nasarawa State, Nigeria.

PubMed

Ishaleku, D; Sar, T T; Houmsou, R S

2011-02-01

To evaluate the prevalence of Sabmonella typhi (S.typhi) among subjects attending College of Education Health Clinic, Akwanga, Nasarawa state from the year. 2005 to 2007 and to recommend some preventive measures to the populace. Blood samples were tested for infection using the widal test. Out of the 793 patients examined, 579(73.0%) were positive with 174 (30.05%), 254(43.86%) and 151(26.07%) for the years 2005, 2006 and 2007 respectively. The age range with the highest prevalence of infection for the period was 21-30 with 207(35.75%) followed by 31-40 year group with 133 (22.97%). Chi-square analysis showed no significant difference in infection between males and females (P>0.05). The results of this study provide a useful guide in the formulation of S. typhi control measures in tertiary institutions in the State and also help to check the spread of the pathogen in the general population. Copyright © 2011 Hainan Medical College. Published by Elsevier B.V. All rights reserved.

Molecular characterization of the Salmonella typhi StpA protein that is related to both Yersinia YopE cytotoxin and YopH tyrosine phosphatase.

PubMed

Arricau, N; Hermant, D; Waxin, H; Popoff, M Y

1997-01-01

Analysis of the nucleotide sequence of a 4-kb DNA fragment located between the sip and iag loci on Salmonella typhi chromosome revealed three open reading frames, termed sipF, ctpA and stpA. The 82-amino-acid (aa) sipF product showed extensive similarity to the lacP protein from S. typhimurium. The StpA protein (535 aa) exhibited significant similarity to both Yersinia enterocolitica YopE cytotoxin and YopH tyrosine phosphatase. The CtpA polypeptide (130 aa) might be the molecular chaperone of the StpA protein.

Occurrence of β-lactamase genes among non-Typhi Salmonella enterica isolated from humans, food animals, and retail meats in the United States and Canada.

PubMed

Sjölund-Karlsson, Maria; Howie, Rebecca L; Blickenstaff, Karen; Boerlin, Patrick; Ball, Takiyah; Chalmers, Gabhan; Duval, Brea; Haro, Jovita; Rickert, Regan; Zhao, Shaohua; Fedorka-Cray, Paula J; Whichard, Jean M

2013-06-01

Non-Typhi Salmonella cause over 1.7 million cases of gastroenteritis in North America each year, and food-animal products are commonly implicated in human infections. For invasive infections, antimicrobial therapy is indicated. In North America, the antimicrobial susceptibility of Salmonella is monitored by the U.S. National Antimicrobial Resistance Monitoring System (NARMS) and The Canadian Integrated Program for Antimicrobial Resistance Surveillance (CIPARS). In this study, we determined the susceptibility to cephalosporins by broth microdilution among 5,041 non-Typhi Salmonella enterica isolated from food animals, retail meats, and humans. In the United States, 109 (4.6%) of isolates collected from humans, 77 (15.7%) from retail meat, and 140 (10.6%) from food animals displayed decreased susceptibility to cephalosporins (DSC). Among the Canadian retail meat and food animal isolates, 52 (13.0%) and 42 (9.4%) displayed DSC. All isolates displaying DSC were screened for β-lactamase genes (bla(TEM), bla(SHV), bla(CMY), bla(CTX-M), and bla(OXA-1)) by polymerase chain reaction. At least one β-lactamase gene was detected in 74/109 (67.9%) isolates collected from humans, and the bla(CMY) genes were most prevalent (69/109; 63.3%). Similarly, the bla(CMY) genes predominated among the β-lactamase-producing isolates collected from retail meats and food animals. Three isolates from humans harbored a bla(CTX-M-15) gene. No animal or retail meat isolates harbored a bla(CTX-M) or bla(OXA-1) gene. A bla(TEM) gene was found in 5 human, 9 retail meat, and 17 animal isolates. Although serotype distributions varied among human, retail meat, and animal sources, overlap in bla(CMY)-positive serotypes across sample sources supports meat and food-animal sources as reservoirs for human infection.

The CRISPR/Cas Immune System Is an Operon Regulated by LeuO, H-NS, and Leucine-Responsive Regulatory Protein in Salmonella enterica Serovar Typhi ▿ †

PubMed Central

Medina-Aparicio, L.; Rebollar-Flores, J. E.; Gallego-Hernández, A. L.; Vázquez, A.; Olvera, L.; Gutiérrez-Ríos, R. M.; Calva, E.; Hernández-Lucas, I.

2011-01-01

Prokaryotes have developed multiple strategies to survive phage attack and invasive DNA. Recently, a novel genetic program denominated the CRISPR/Cas system was demonstrated to have a role in these biological processes providing genetic immunity. This defense mechanism is widespread in the Archaea and Bacteria, suggesting an ancient origin. In the last few years, progress has been made regarding the functionality of the CRISPR/Cas system; however, many basic aspects of the system remain unknown. For instance, there are few studies about the conditions and regulators involved in its transcriptional control. In this work, we analyzed the transcriptional organization of the CRISPR/Cas system as well as the positive and negative regulators involved in its genetic expression in Salmonella enterica serovar Typhi. The results obtained show that in S. Typhi the CRISPR/Cas system is a LeuO-dependent operon silenced by the global regulator LRP, in addition to the previously known nucleoid-associated protein H-NS; both LRP and H-NS bind upstream and downstream of the transcriptional start site of casA. In this study, relevant nucleotides of the casA regulatory region that mediate its LeuO transcriptional activation were identified. Interestingly, specific growth conditions (N-minimal medium) were found for the LeuO-independent expression of the CRISPR/Cas system in S. Typhi. Thus, our work provides evidence that there are multiple modulators involved in the genetic expression of this immune system in S. Typhi IMSS-1. PMID:21398529

Salmonella Typhi and Plasmodium falciparum co-infection in a 12-year old girl with haemoglobin E trait from a non-malarious area in Bangladesh.

PubMed

Chowdhury, Fahmida; Chisti, Mohammod J; Khan, Ahmadul H; Chowdhury, Mohammad A; Pietroni, Mark A C

2010-10-01

A 12-year old girl from Uttar Badda, Dhaka, Bangladesh, was admitted to the Dhaka Hospital of ICDDR,B, with a 23-day history of fever and diarrhoea. After admission, she was treated for culture-proven Salmonella Typhi-associated infection and was discovered to be heterozygous for haemoglobin E. Despite treatment with appropriate antibiotics, the patient's condition did not improve, prompting further investigation, which revealed malaria due to Plasmodium falciparum. Dhaka is considered a malaria-free zone, and the patient denied recent travel outside Dhaka. Subsequently, the patient recovered fully on antimalarial therapy.

Biofilm Formation Protects Salmonella from the Antibiotic Ciprofloxacin In Vitro and In Vivo in the Mouse Model of chronic Carriage.

PubMed

González, Juan F; Alberts, Halley; Lee, Joel; Doolittle, Lauren; Gunn, John S

2018-01-09

Typhoid fever is caused by the human-restricted pathogen Salmonella enterica sv. Typhi. Approximately 5% of people that resolve the disease become chronic carriers, with the gallbladder as the main reservoir of the bacteria. Of these, about 90% present with gallstones, on which Salmonella form biofilms. Because S. Typhi is a human-restricted pathogen, these carriers are the main source of dissemination of the disease; unfortunately, antibiotic treatment has shown to be an ineffective therapy. This is believed to be caused by the inherent antibiotic resistance conferred by Salmonella biofilms growing on gallstones. The gallstone mouse model with S. Typhimurium has proven to be an excellent surrogate for S. Typhi chronic infection. In this study, we test the hypothesis that the biofilm state confers Salmonella with the increased resistance to antibiotics observed in cases of chronic carriage. We found that, in the biofilm state, Salmonella is significantly more resistant to ciprofloxacin, a common antibiotic used for the treatment of Salmonella, both in vitro (p < 0.001 for both S. Typhi and S. Typhimurium with respect to planktonic cells) and in vivo (p = 0.0035 with respect to control mice).

Septic arthritis of the hip in a Cambodian child caused by multidrug-resistant Salmonella enterica serovar Typhi with intermediate susceptibility to ciprofloxacin treated with ceftriaxone and azithromycin.

PubMed

Pocock, J M; Khun, P A; Moore, C E; Vuthy, S; Stoesser, N; Parry, C M

2014-08-01

Septic arthritis is a rare complication of typhoid fever. A 12-year-old boy without pre-existing disease attended a paediatric hospital in Cambodia with fever and left hip pain. A hip synovial fluid aspirate grew multidrug-resistant Salmonella enterica ser. Typhi with intermediate susceptibility to ciprofloxacin. Arthrotomy, 2 weeks of intravenous ceftriaxone and 4 weeks of oral azithromycin led to resolution of symptoms. The optimum management of septic arthritis in drug-resistant typhoid is undefined.

[Formation and persistence of L-variants of Salmonella typhi in experimental typhoid and in carriers].

PubMed

Levina, G A; Prozorovskiĭ, S V; Iagud, S L; Grumman, M I; Gorelov, A L

1981-07-01

The possibility of the induction and persistence of S. typhi L-forms in the process of experimental typhoid infection and carriership has been studied in rabbits. This study has revealed that the process of L-transformation leading to the appearance of the imbalanced growth forms and unstable L-forms of S. typhi in the organism of the animals infected with S. typhi culture may occur under the conditions of carriership. Such changed forms can be detected in the organism of the animals 18 months after the primary infection.

First report on antimicrobial resistance and molecular characterization of Salmonella enterica serotype Typhi isolated from human specimens in Luanda, Angola.

PubMed

Francisco, Moisés; Costa, Sofia Santos; Belas, Adriana; Ramos, Jorge; Couto, Isabel; Pomba, Constança; Viveiros, Miguel

2018-02-09

Typhoid fever is a common infection in Africa and in spite of scarce surveillance reports, its incidence is commonly considered high by the Angolan Health system. Drug-resistant Salmonella enterica serotype Typhi has emerged, turning antimicrobial susceptibility testing essential to provide clinical guidance. This is the first report analyzing antimicrobial resistance patterns and population structure of the few S. enterica ser. Typhi isolated from patients with Typhoid fever in Luanda, Angola. Isolates were collected by the National Institute of Public Health of Angola, between September 2013 and May 2014. A total of 10 isolates were identified by API20E system and serotyping, and the genus confirmed by PCR. All isolates were tested for antibiotic susceptibility and the presence of resistance genes (blaCTX-M, blaSHV, blaTEM, blaOXA-1, several plasmid-borne genes encoding AmpC β-lactamases, sul and qnr genes, dfrIa, dfrA12, aac(6')- Ib, cmlA and floR) screened by PCR. Isolates were typed by PFGE and MLST. Several isolates were identified with resistance to trimethoprim-sulfamethoxazole (n=6), beta-lactams (n=5), chloramphenicol (n=1) and reduced susceptibility to ciprofloxacin (n=2). PFGE revealed eight closely related restriction patterns and MLST grouped these in three sequence types: ST1, ST2 and ST8, with ST2 being predominant. This first epidemiological report provides a preliminary portray of the S. enterica ser. Typhi strains that circulate in Luanda, Angola and emphasizes the demand for a continuous monitoring of this pathogen to provide information to implement better epidemiological strategies for the control of Typhoid fever in Angola. Copyright © 2018 International Society for Chemotherapy of Infection and Cancer. Published by Elsevier Ltd. All rights reserved.

Ten years experience of Salmonella infections in Cambridge, UK.

PubMed

Matheson, Nicholas; Kingsley, Robert A; Sturgess, Katherine; Aliyu, Sani H; Wain, John; Dougan, Gordon; Cooke, Fiona J

2010-01-01

Review of all Salmonella infections diagnosed in the Cambridge area over 10 years. All Salmonella enterica isolated in the Clinical Microbiology Laboratory, Addenbrooke's Hospital between 1.1.1999 and 31.12.2008 were included. Patient demographics, serotype and additional relevant details (travel history, resistance-type, phage-type) were recorded. 1003 episodes of Salmonella gastroenteritis were confirmed by stool culture, representing 88 serotypes. Serotypes Enteritidis (59%), Typhimurium (4.7%), Virchow (2.6%), Newport (1.8%) and Braenderup (1.7%) were the 5 most common isolates. There were an additional 37 invasive Salmonella infections (32 blood cultures, 4 tissue samples, 1 CSF). 13/15 patients with Salmonella Typhi or Salmonella Paratyphi isolated from blood or faeces with an available travel history had returned from the Indian subcontinent. 8/10 S. Typhi or Paratyphi isolates tested had reduced susceptibility to fluoroquinolones (MIC > or = 0.125 mg/L). 7/21 patients with non-typhoidal Salmonella bacteraemia were known to be immunosuppressed. This study describes Salmonella serotypes circulating within a defined geographical area over a decade. Prospective molecular analysis of isolates of S. enterica by multi-locus sequence typing (MLST) and single nucleotide polymorphism (SNP) detection will determine the geo-phylogenetic relationship of isolates within our region. 2009 The British Infection Society. Published by Elsevier Ltd. All rights reserved.

Evaluation of microplate immunocapture method for detection of Vibrio cholerae, Salmonella Typhi and Shigella flexneri from food.

PubMed

Fakruddin, Md; Hossain, Md Nur; Ahmed, Monzur Morshed

2017-08-29

Improved methods with better separation and concentration ability for detection of foodborne pathogens are in constant need. The aim of this study was to evaluate microplate immunocapture (IC) method for detection of Salmonella Typhi, Shigella flexneri and Vibrio cholerae from food samples to provide a better alternative to conventional culture based methods. The IC method was optimized for incubation time, bacterial concentration, and capture efficiency. 6 h incubation and log 6 CFU/ml cell concentration provided optimal results. The method was shown to be highly specific for the pathogens concerned. Capture efficiency (CE) was around 100% of the target pathogens, whereas CE was either zero or very low for non-target pathogens. The IC method also showed better pathogen detection ability at different concentrations of cells from artificially contaminated food samples in comparison with culture based methods. Performance parameter of the method was also comparable (Detection limit- 25 CFU/25 g; sensitivity 100%; specificity-96.8%; Accuracy-96.7%), even better than culture based methods (Detection limit- 125 CFU/25 g; sensitivity 95.9%; specificity-97%; Accuracy-96.2%). The IC method poses to be the potential to be used as a method of choice for detection of foodborne pathogens in routine laboratory practice after proper validation.

Characterization of the RpoS Status of Clinical Isolates of Salmonella enterica

PubMed Central

Robbe-Saule, Véronique; Algorta, Gabriela; Rouilhac, Isabelle; Norel, Françoise

2003-01-01

The stationary-phase-inducible sigma factor, σS (RpoS), is the master regulator of the general stress response in Salmonella and is required for virulence in mice. rpoS mutants can frequently be isolated from highly passaged laboratory strains of Salmonella. We examined the rpoS status of 116 human clinical isolates of Salmonella, including 41 Salmonella enterica serotype Typhi strains isolated from blood, 38 S. enterica serotype Typhimurium strains isolated from blood, and 37 Salmonella serotype Typhimurium strains isolated from feces. We examined the abilities of these strains to produce the σS protein, to express RpoS-dependent catalase activity, and to resist to oxidative stress in the stationary phase of growth. We also carried out complementation experiments with a cloned wild-type rpoS gene. Our results showed that 15 of the 41 Salmonella serotype Typhi isolates were defective in RpoS. We sequenced the rpoS allele of 12 strains. This led to identification of small insertions, deletions, and point mutations resulting in premature stop codons or affecting regions 1 and 2 of σS, showing that the rpoS mutations are not clonal. Thus, mutant rpoS alleles can be found in freshly isolated clinical strains of Salmonella serotype Typhi, and they may affect virulence properties. Interestingly however, no rpoS mutants were found among the 75 Salmonella serotype Typhimurium isolates. Strains that differed in catalase activity and resistance to hydrogen peroxide were found, but the differences were not linked to the rpoS status. This suggests that Salmonella serotype Typhimurium rpoS mutants are counterselected because rpoS plays a role in the pathogenesis of Salmonella serotype Typhimurium in humans or in the transmission cycle of the disease. PMID:12902215

Evaluation of Salmonella enterica serovar Typhi (Ty2 aroC-ssaV-) M01ZH09, with a defined mutation in the Salmonella pathogenicity island 2, as a live, oral typhoid vaccine in human volunteers.

PubMed

Kirkpatrick, B D; McKenzie, Robin; O'Neill, J Patrick; Larsson, Catherine J; Bourgeois, A Louis; Shimko, Janet; Bentley, Matthew; Makin, Jill; Chatfield, Steve; Hindle, Zoë; Fidler, Christine; Robinson, Brad E; Ventrone, Cassandra H; Bansal, Nivedita; Carpenter, Colleen M; Kutzko, Deborah; Hamlet, Sandra; LaPointe, Casey; Taylor, David N

2006-01-12

Salmonella enterica serovar Typhi strains with mutations in the Salmonella pathogenicity island-2 (SPI-2) may represent an effective strategy for human vaccine development, and a vectoring system for heterologous antigens. S. Typhi (Ty2 aroC-ssaV-) M01ZH09 is an attenuated, live, oral typhoid vaccine harboring defined deletion mutations in ssaV, which encodes an integral component in the SPI-2 type III secretion system (TTSS), as well as a mutation in an aromatic biosynthetic pathway needed for bacterial growth in vivo (aroC). SPI-2 mutant vaccines have yet to be evaluated in a large, randomized human trial. A simplified or single-oral dose oral typhoid vaccine using the SPI-2 strategy would offer significant advantages over the currently licensed typhoid vaccines. We performed a double-blinded, placebo-controlled, dose-escalating clinical trial in 60 healthy adult volunteers to determine the tolerability and immunogenicity of a single dose of M01ZH09. Three groups of 20 healthy adult volunteers were enrolled; 16 in each group received a single oral dose of the freeze-dried vaccine at 5 x 10(7), 5 x 10(8) or 5 x 10(9)CFU in a bicarbonate buffer. Four volunteers in each cohort received placebo in the same buffer. Adverse events were infrequent and not statistically different between vaccine and placebo recipients, although two subjects in the mid-range dose and three subjects in the highest dose had temperature measurements >37.5 degrees C. No blood or urine cultures were positive for M01ZH09, and fecal shedding was brief. The immune response was dose-related; the highest vaccine dose (5 x 10(9)CFU) was the most immunogenic. All tested subjects receiving the highest dose had a significant ASC response (mean 118 spots/10(6) cells). A >or=4-fold increase in antibody titer for S. Typhi LPS or flagellin was detected in 75% of volunteers in the highest-dose cohort by day 28. The SPI-2 mutant vaccine, M01ZH09, is a promising typhoid vaccine candidate and deserves further

Epidemiological studies on Salmonella in a certain area ("Walcheren project"). I. The presence of Salmonella in man, pigs, insects, seagulls and in foods and effluents.

PubMed

Edel, W; van Schothorst, M; Kampelmacher, E H

1976-08-01

During a certain period various materials (pigs, foods, insects, seagull droppings, chopping-block scrapings from butcher's shops, effluents of sewage treatment plants and stools of patients) were examined for the presence of Salmonella at the same time in a relatively small area (Walcheren). Certain types of Salmonella (S. typhi murium type II 505, S. panama, S. infantis and S. brandenburg) were frequently isolated from almost all materials examined. This may indicate the existence of Salmonella contamination cycles: one may think of the cycle: slaughter animal (infected from the environment and/or by meal) - meat - consumer - patient or healthy carrier - effluent and surface water - insects, birds and rodents - slaughter animal or meat and possibly other foods - consumer.

Clonal Expansion and Microevolution of Quinolone-Resistant Salmonella enterica Serotype Typhi in Vietnam from 1996 to 2004▿

PubMed Central

Le, Thi Anh Hong; Fabre, Laëtitia; Roumagnac, Philippe; Grimont, Patrick A. D.; Scavizzi, Maurice R.; Weill, François-Xavier

2007-01-01

Salmonella enterica serotype Typhi clinical isolates (n = 91) resistant to nalidixic acid (Nalr) were collected from sporadic cases and minor outbreaks throughout Vietnam between 1996 and 2004. These isolates were typed and compared by four methods: Vi phage typing, PstI ribotyping, XbaI and SpeI pulsed-field gel electrophoresis (PFGE), and single-nucleotide polymorphism (SNP) analysis. The results indicated that 65% of the isolates were not typeable by Vi phage typing. In contrast, the ribotyping and, with more accuracy, the SNP analysis methods indicated that all Nalr isolates belonged to a single clone (ribotype 3a, haplotype H58) that was found previously and that largely consisted of plasmid-encoded multidrug-resistant serotype Typhi isolates. PFGE demonstrated the occurrence of microevolution within this clone. We identified two major combined PFGE profiles: X1-S1 and X3-S6. X3-S6 predominated between 1996 and 2002 but was replaced by X1-S1 after 2002. Nevertheless, PFGE, with a Simpson's index of 0.78, was not considered an optimal discriminatory method for investigating typhoid fever outbreaks in Vietnam. The rate of quinolone resistance increased and the rate of multidrug resistance decreased during the study period. From 2002 to 2004, 80.6% of the isolates from South Vietnam were resistant only to Nal. The mechanism of Nal resistance in most of the isolates (94%) was a mutation in the quinolone resistance-determining chromosomal region of gyrA that led to the amino acid substitution Ser83Phe. No plasmid-located qnrA, qnrB, or qnrS was detected. PMID:17728470

[Epidemiological characteristics of typhoid fever and antibiotic susceptibility testing of Salmonella Typhi isolates in Guangxi, 1994-2013].

PubMed

Wang, Mingliu; Kan, Biao; Yang, Jin; Lin, Mei; Yan, Meiying; Zeng, Jun; Quan, Yi; Liao, Hezhuang; Zhou, Lingyun; Jiang, Zhenling; Huang, Dehui

2014-08-01

Through analyzing the typhoid epidemics and to determine and monitor regional resistance characteristics of the shift of drug resistant profile on Salmonella (S.) Typhi, to understand the related epidemiological characteristics of typhoid fever and to provide evidence for the development of strategies, in Guangxi. Data of typhoid fever from surveillance and reporting system between 1994 to 2013 was collected and statistically analyzed epidemiologically. The susceptibility of 475 S. Typhi isolates from patients on ten antibiotics was tested by broth micro-dilution method and minimum inhibition concentration was obtained and interpreted based on the CLSI standard. From 1994 to 2013, a total of 57 928 cases of typhoid fever were reported in Guangxi province with an annual incidence of 6.29/100 000 and mortality as 0.03%. The higher incidence was observed in the population under 20 years of age. There was no significant difference on incidence between male and female, but farmers and students were among the hardest hit groups. More cases were seen from the northern part of the province. Cases appeared all year round with the peak from May to October. A total of 13 major outbreaks during 2001 to 2013 were reported and the main transmission route was water-borne. All the strains were sensitive to third generation cephalosporins cefotaxime and fluoroquinolones norfloxacin. The susceptibility rates to tetracycline, chloramphenicol, ampicillin and gentamicin was around 98% but relative lower susceptible rate to ciprofloxacin was seen as 89.89% . The lowest susceptibility was found for streptomycin and sulfamethoxazole agents, with the rates as 67.73% and 65.89% , respectively. One strain was found to have been resistant to ciprofloxacin and another 47 isolates with reduced susceptibility to ciprofloxacin. Twenty eight isolates were found to be resistant to multiple antibiotics and one displayed ampicillin, chloramphenicol, streptomycin, sulfamethoxazole tetracycline and

Human genetic variation in VAC14 regulates Salmonella invasion and typhoid fever through modulation of cholesterol.

PubMed

Alvarez, Monica I; Glover, Luke C; Luo, Peter; Wang, Liuyang; Theusch, Elizabeth; Oehlers, Stefan H; Walton, Eric M; Tram, Trinh Thi Bich; Kuang, Yu-Lin; Rotter, Jerome I; McClean, Colleen M; Chinh, Nguyen Tran; Medina, Marisa W; Tobin, David M; Dunstan, Sarah J; Ko, Dennis C

2017-09-12

Risk, severity, and outcome of infection depend on the interplay of pathogen virulence and host susceptibility. Systematic identification of genetic susceptibility to infection is being undertaken through genome-wide association studies, but how to expeditiously move from genetic differences to functional mechanisms is unclear. Here, we use genetic association of molecular, cellular, and human disease traits and experimental validation to demonstrate that genetic variation affects expression of VAC14, a phosphoinositide-regulating protein, to influence susceptibility to Salmonella enterica serovar Typhi ( S Typhi) infection. Decreased VAC14 expression increased plasma membrane cholesterol, facilitating Salmonella docking and invasion. This increased susceptibility at the cellular level manifests as increased susceptibility to typhoid fever in a Vietnamese population. Furthermore, treating zebrafish with a cholesterol-lowering agent, ezetimibe, reduced susceptibility to S Typhi. Thus, coupling multiple genetic association studies with mechanistic dissection revealed how VAC14 regulates Salmonella invasion and typhoid fever susceptibility and may open doors to new prophylactic/therapeutic approaches.

Human genetic variation in VAC14 regulates Salmonella invasion and typhoid fever through modulation of cholesterol

PubMed Central

Alvarez, Monica I.; Glover, Luke C.; Luo, Peter; Wang, Liuyang; Theusch, Elizabeth; Oehlers, Stefan H.; Walton, Eric M.; Tram, Trinh Thi Bich; Kuang, Yu-Lin; Rotter, Jerome I.; McClean, Colleen M.; Chinh, Nguyen Tran; Medina, Marisa W.; Dunstan, Sarah J.

2017-01-01

Risk, severity, and outcome of infection depend on the interplay of pathogen virulence and host susceptibility. Systematic identification of genetic susceptibility to infection is being undertaken through genome-wide association studies, but how to expeditiously move from genetic differences to functional mechanisms is unclear. Here, we use genetic association of molecular, cellular, and human disease traits and experimental validation to demonstrate that genetic variation affects expression of VAC14, a phosphoinositide-regulating protein, to influence susceptibility to Salmonella enterica serovar Typhi (S. Typhi) infection. Decreased VAC14 expression increased plasma membrane cholesterol, facilitating Salmonella docking and invasion. This increased susceptibility at the cellular level manifests as increased susceptibility to typhoid fever in a Vietnamese population. Furthermore, treating zebrafish with a cholesterol-lowering agent, ezetimibe, reduced susceptibility to S. Typhi. Thus, coupling multiple genetic association studies with mechanistic dissection revealed how VAC14 regulates Salmonella invasion and typhoid fever susceptibility and may open doors to new prophylactic/therapeutic approaches. PMID:28827342

What proportion of Salmonella Typhi cases are detected by blood culture? A systematic literature review.

PubMed

Mogasale, Vittal; Ramani, Enusa; Mogasale, Vijayalaxmi V; Park, JuYeon

2016-05-17

Blood culture is often used in definitive diagnosis of typhoid fever while, bone marrow culture has a greater sensitivity and considered reference standard. The sensitivity of blood culture measured against bone marrow culture results in measurement bias because both tests are not fully sensitive. Here we propose a combination of the two cultures as a reference to define true positive S. Typhi cases. Based on a systematic literature review, we identified ten papers that had performed blood and bone marrow culture for S. Typhi in same subjects. We estimated the weighted mean of proportion of cases detected by culture measured against true S. Typhi positive cases using a random effects model. Of 529 true positive S. Typhi cases, 61 % (95 % CI 52-70 %) and 96 % (95 % CI 93-99 %) were detected by blood and bone marrow cultures respectively. Blood culture sensitivity was 66 % (95 % CI 56-75 %) when compared with bone marrow culture results. The use of blood culture sensitivity as a proxy measure to estimate the proportion of typhoid fever cases detected by blood culture is likely to be an underestimate. As blood culture sensitivity is used as a correction factor in estimating typhoid disease burden, epidemiologists and policy makers should account for the underestimation.

Genomic Signature of Multidrug-Resistant Salmonella enterica Serovar Typhi Isolates Related to a Massive Outbreak in Zambia between 2010 and 2012

PubMed Central

Leekitcharoenphon, Pimlapas; Lukjancenko, Oksana; Lukwesa-Musyani, Chileshe; Tambatamba, Bushimbwa; Mwaba, John; Kalonda, Annie; Nakazwe, Ruth; Kwenda, Geoffrey; Jensen, Jacob Dyring; Svendsen, Christina A.; Dittmann, Karen K.; Kaas, Rolf S.; Cavaco, Lina M.; Aarestrup, Frank M.; Hasman, Henrik; Mwansa, James C. L.

2014-01-01

Retrospectively, we investigated the epidemiology of a massive Salmonella enterica serovar Typhi outbreak in Zambia during 2010 to 2012. Ninety-four isolates were susceptibility tested by MIC determinations. Whole-genome sequence typing (WGST) of 33 isolates and bioinformatic analysis identified the multilocus sequence type (MLST), haplotype, plasmid replicon, antimicrobial resistance genes, and genetic relatedness by single nucleotide polymorphism (SNP) analysis and genomic deletions. The outbreak affected 2,040 patients, with a fatality rate of 0.5%. Most (83.0%) isolates were multidrug resistant (MDR). The isolates belonged to MLST ST1 and a new variant of the haplotype, H58B. Most isolates contained a chromosomally translocated region containing seven antimicrobial resistance genes, catA1, blaTEM-1, dfrA7, sul1, sul2, strA, and strB, and fragments of the incompatibility group Q1 (IncQ1) plasmid replicon, the class 1 integron, and the mer operon. The genomic analysis revealed 415 SNP differences overall and 35 deletions among 33 of the isolates subjected to whole-genome sequencing. In comparison with other genomes of H58, the Zambian isolates separated from genomes from Central Africa and India by 34 and 52 SNPs, respectively. The phylogenetic analysis indicates that 32 of the 33 isolates sequenced belonged to a tight clonal group distinct from other H58 genomes included in the study. The small numbers of SNPs identified within this group are consistent with the short-term transmission that can be expected over a period of 2 years. The phylogenetic analysis and deletions suggest that a single MDR clone was responsible for the outbreak, during which occasional other S. Typhi lineages, including sensitive ones, continued to cocirculate. The common view is that the emerging global S. Typhi haplotype, H58B, containing the MDR IncHI1 plasmid is responsible for the majority of typhoid infections in Asia and sub-Saharan Africa; we found that a new variant of the

Overexpression of Salmonella enterica serovar Typhi recA gene confers fluoroquinolone resistance in Escherichia coli DH5α.

PubMed

Yassien, M A M; Elfaky, M A

2015-11-01

A spontaneous fluoroquinolone-resistant mutant (STM1) was isolated from its parent Salmonella enterica serovar Typhi (S. Typhi) clinical isolate. Unlike its parent isolate, this mutant has selective resistance to fluoroquinolones without any change in its sensitivity to various other antibiotics. DNA gyrase assays revealed that the fluoroquinolone resistance phenotype of the STM1 mutant did not result from alteration of the fluoroquinolone sensitivity of the DNA gyrase isolated from it. To study the mechanism of fluoroquinolone resistance, a genomic library from the STM1 mutant was constructed in Escherichia coli DH5α and two recombinant plasmids were obtained. Only one of these plasmids (STM1-A) conferred the selective fluoroquinolone resistance phenotype to E. coli DH5α. The chromosomal insert from STM1-A, digested with EcoRI and HindIII restriction endonucleases, produced two DNA fragments and these were cloned separately into pUC19 thereby generating two new plasmids, STM1-A1 and STM1-A2. Only STM1-A1 conferred the selective fluoroquinolone resistance phenotype to E. coli DH5α. Sequence and subcloning analyses of STM1-A1 showed the presence of an intact RecA open reading frame. Unlike that of the wild-type E. coli DH5α, protein analysis of a crude STM1-A1 extract showed overexpression of a 40 kDa protein. Western blotting confirmed the 40 kDa protein band to be RecA. When a RecA PCR product was cloned into pGEM-T and introduced into E. coli DH5α, the STM1-A11 subclone retained fluoroquinolone resistance. These results suggest that overexpression of RecA causes selective fluoroquinolone resistance in E. coli DH5α.

Identification and Characterization of a Gene stp17 Located on the Linear Plasmid pBSSB1 as an Enhanced Gene of Growth and Motility in Salmonella enterica Serovar Typhi

PubMed Central

Zhang, Haifang; Zhu, Yunxia; Xie, Xiaofang; Wang, Min; Du, Hong; Xu, Shungao; Zhang, Ying; Gong, Mingyu; Ni, Bin; Xu, Huaxi; Huang, Xinxiang

2016-01-01

The linear plasmid pBSSB1 mediates the flagellar phase variation in H:z66 positive Salmonella enterica serovar Typhi (S. Typhi). The gene named stp17 (S. Typhi plasmid number 17 gene) is located on pBSSB1 and encodes the protein STP17. The expression pattern at the protein-level and function of STP17 remains unknown. In this study, the recombinant protein STP17His6 was expressed, purified and used to prepare the polyclonal anti-STP17 antibody. We detected protein-level expression of stp17 in S. Typhi and further investigated the protein expression characteristics of stp17 in different growth phases by western blot analysis. The effects of STP17 on bacterial growth and motility were analyzed. In addition, the structure of STP17 was predicted and the active site of STP17 was identified by site-directed mutagenesis. The results showed that STP17 was expressed stably in the wild type strain of S. Typhi. STP17 expression at the protein level peaks when cultures reach an OD600 value of 1.2. The growth rate and motility of the Δstp17 strain were significantly decreased compared with the wild type strain (P < 0.05) and this phenotype was restored in the stp17 complementary strain. Moreover, the growth rate and motility of the stp17 over-expression strain was greater than the wild type strain. STP17 contains nine Helix segments, six Stand segments and some Coil segments in the secondary structural level. The top-ranked 3-D structure of STP17 predicted by I-TASSER contains a putative ATPase domain and the amino acid residues of GLY16, GLY19, LYS20, ASN133, LYS157, and LYS158 may be the active site residues of STP17. Finally, STP17 was able to catalyze the ATP to ADP reaction, suggesting that STP17 may be an ATPase. To our knowledge, this is the first report describing the protein expression characteristics of STP17 in S. Typhi, showing that STP17 promotes bacterial growth and motility, which may be associated with its potential ATPase activity. PMID:27761429

Evaluation of the antibacterial activity of selected Pakistani honeys against multi-drug resistant Salmonella typhi.

PubMed

Hussain, Muhammad Barkaat; Hannan, Abdul; Akhtar, Naeem; Fayyaz, Ghulam Qadir; Imran, Muhammad; Saleem, Sidrah; Qureshi, Imtiaz Ahmed

2015-02-26

The development of resistance to conventional anti-typhoid drugs and the recent emergence of fluoroquinolone resistance have made it very difficult and expensive to treat typhoid fever. As the therapeutic strategies become even more limited, it is imperative to investigate non-conventional modalities. In this context, honey is a potential candidate for combating antimicrobial resistance because it contains a broad repertoire of antibacterial compounds which act synergistically at multiple sites, thus making it less likely that the bacteria will become resistant. The in vitro antibacterial activity of 100 unifloral honey samples against a blood culture isolate of multi-drug resistant (MDR) Salmonella typhi were investigated. All honey samples were evaluated for both total (acidity, osmolarity, hydrogen peroxide and non-peroxide activity) and plant derived non-peroxide antibacterial activity by agar well diffusion assay at 50% and 25% dilution in sterile distilled water and 25% in catalase solution. Manuka (Unique Manuka Factor-21) honey was used for comparison. The phenol equivalence of each honey sample from 2% to 7% (w/v) phenol was obtained from regression analysis. The antibacterial potential of each honey sample was expressed as its equivalent phenol concentration. The honey samples which showed antibacterial activity equivalent to or greater than manuka honey were considered therapeutically active honeys. Nineteen honey samples (19%) displayed higher hydrogen peroxide related antibacterial activity (16-20% phenol), which is more than that of manuka honey (21-UMF). A total of 30% of the honey samples demonstrated antibacterial activity between 11 and 15% phenol similar to that of manuka honey while 51% of the honey samples did not exhibit any zone of inhibition against MDR-S. typhi at 50% (w/v) dilution. None of the indigenous honey samples displayed non-peroxide antibacterial activity. Only manuka honey showed non-peroxide antibacterial activity at 25

EFFECT OF THE ANTIMUTAGENS VANILLIN AND CINNAMALDEHYDE ON THE SPONTANEOUS MUTATION SPECTRA OF SALMONELLA TA104

EPA Science Inventory

Effect of the Antimutagens Vanillin and Cinnamaldehyde on the / Spontaneous Mutation Spectra of Salmonella TAlO4

Vanillin (VAN) and cinnamaldehyde (CIN) are dietary antimutagens that, when added to assay plates, reduced the spontaneous mutant frequency in Salmonella typhi...

Salmonella enterica Serotype Napoli is the First Cause of Invasive Nontyphoidal Salmonellosis in Lombardy, Italy (2010-2014), and Belongs to Typhi Subclade.

PubMed

Huedo, Pol; Gori, Maria; Zolin, Anna; Amato, Ettore; Ciceri, Giulia; Bossi, Anna; Pontello, Mirella

2017-03-01

Salmonella enterica serotype Napoli (S. Napoli) is currently emerging in Europe and particularly in Italy, where in 2014 it caused a large outbreak associated with elevated rates of bacteremia. However, no study has yet investigated its invasive ability and phylogenetic classification. Here, we show that between 2010 and 2014, S. Napoli was the first cause of invasive salmonellosis affecting 40 cases out of 687 (invasive index: 5.8%), which is significantly higher than the invasive index of all the other nontyphoidal serotypes (2.0%, p < 0.05). Genomic and phylogenetic analyses of an invasive isolate revealed that S. Napoli belongs to Typhi subclade in clade A, Paratyphi A being the most related serotype and carrying almost identical pattern of typhoid-associated genes. This work presents evidence of invasive capacity of S. Napoli and argues for reconsideration of its nontyphoidal category.

Measurement of Typhi Vi antibodies can be used to assess adaptive immunity in patients with immunodeficiency.

PubMed

Evans, C; Bateman, E; Steven, R; Ponsford, M; Cullinane, A; Shenton, C; Duthie, G; Conlon, C; Jolles, S; Huissoon, A P; Longhurst, H J; Rahman, T; Scott, C; Wallis, G; Harding, S; Parker, A R; Ferry, B L

2018-01-29

Vaccine-specific antibody responses are essential in the diagnosis of antibody deficiencies. Responses to Pneumovax II are used to assess the response to polysaccharide antigens, but interpretation may be complicated. Typhim Vi ® , a polysaccharide vaccine for Salmonella typhoid fever, may be an additional option for assessing humoral responses in patients suspected of having an immunodeficiency. Here we report a UK multi-centre study describing the analytical and clinical performance of a Typhi Vi immunoglobulin (Ig)G enzyme-linked immunosorbent assay (ELISA) calibrated to an affinity-purified Typhi Vi IgG preparation. Intra- and interassay imprecision was low and the assay was linear, between 7·4 and 574 U/ml (slope = 0·99-1·00; R 2  > 0·99); 71% of blood donors had undetectable Typhi Vi IgG antibody concentrations. Of those with antibody concentrations  > 7·4 U/ml, the concentration range was 7·7-167 U/ml. In antibody-deficient patients receiving antibody replacement therapy the median Typhi Vi IgG antibody concentrations were  < 25 U/ml. In vaccinated normal healthy volunteers, the median concentration post-vaccination was 107 U/ml (range 31-542 U/ml). Eight of eight patients (100%) had post-vaccination concentration increases of at least threefold and six of eight (75%) of at least 10-fold. In an antibody-deficient population (n = 23), only 30% had post-vaccination concentration increases of at least threefold and 10% of at least 10-fold. The antibody responses to Pneumovax II and Typhim Vi ® correlated. We conclude that IgG responses to Typhim Vi ® vaccination can be measured using the VaccZyme Salmonella typhi Vi IgG ELISA, and that measurement of these antibodies maybe a useful additional test to accompany Pneumovax II responses for the assessment of antibody deficiencies. © 2018 The Authors. Clinical & Experimental Immunology published by John Wiley & Sons Ltd on behalf of British Society for Immunology.

Non-protein coding RNA genes as the novel diagnostic markers for the discrimination of Salmonella species using PCR.

PubMed

Nithya, Ravichantar; Ahmed, Siti Aminah; Hoe, Chee-Hock; Gopinath, Subash C B; Citartan, Marimuthu; Chinni, Suresh V; Lee, Li Pin; Rozhdestvensky, Timofey S; Tang, Thean-Hock

2015-01-01

Salmonellosis, a communicable disease caused by members of the Salmonella species, transmitted to humans through contaminated food or water. It is of paramount importance, to generate accurate detection methods for discriminating the various Salmonella species that cause severe infection in humans, including S. Typhi and S. Paratyphi A. Here, we formulated a strategy of detection and differentiation of salmonellosis by a multiplex polymerase chain reaction assay using S. Typhi non-protein coding RNA (sRNA) genes. With the designed sequences that specifically detect sRNA genes from S. Typhi and S. Paratyphi A, a detection limit of up to 10 pg was achieved. Moreover, in a stool-seeding experiment with S. Typhi and S. Paratyphi A, we have attained a respective detection limit of 15 and 1.5 CFU/mL. The designed strategy using sRNA genes shown here is comparatively sensitive and specific, suitable for clinical diagnosis and disease surveillance, and sRNAs represent an excellent molecular target for infectious disease.

CRISPRs: Molecular Markers for Tracking Antibiotic Resistant Strains of Salmonella Enterica

DTIC Science & Technology

2014-01-01

S.Paratyphi A, B and C) are confined to human hosts and cause typhoid and paratyphoid (enteric) fevers . These are spread from human to human—often shed by...poisoning) with symptoms of diarrhea, fever , and abdominal cramps that run 5-7 days. In contrast, non- typhoidal salmonellosis in sub-Saharan Africa... typhoid fever , due to Salmonella Typhi, is an important cause of illness and death. Most serotype Typhi infections in the United States are acquired

Identification and Characterization of a Cis-Encoded Antisense RNA Associated with the Replication Process of Salmonella enterica Serovar Typhi

PubMed Central

Dadzie, Isaac; Xu, Shungao; Ni, Bin; Zhang, Xiaolei; Zhang, Haifang; Sheng, Xiumei; Xu, Huaxi; Huang, Xinxiang

2013-01-01

Antisense RNAs that originate from the complementary strand of protein coding genes are involved in the regulation of gene expression in all domains of life. In bacteria, some of these antisense RNAs are transcriptional noise whiles others play a vital role to adapt the cell to changing environmental conditions. By deep sequencing analysis of transcriptome of Salmonella enterica serovar Typhi, a partial RNA sequence encoded in-cis to the dnaA gene was revealed. Northern blot and RACE analysis confirmed the transcription of this antisense RNA which was expressed mostly in the stationary phase of the bacterial growth and also under iron limitation and osmotic stress. Pulse expression analysis showed that overexpression of the antisense RNA resulted in a significant increase in the mRNA levels of dnaA, which will ultimately enhance their translation. Our findings have revealed that antisense RNA of dnaA is indeed transcribed not merely as a by-product of the cell's transcription machinery but plays a vital role as far as stability of dnaA mRNA is concerned. PMID:23637809

Salmonella L-forms: formation in human bile in vitro and isolation culture from patients' gallbladder samples by a non-high osmotic isolation technique.

PubMed

Wang, D N; Wu, W J; Wang, T; Pan, Y Z; Tang, K L; She, X L; Ding, W J; Wang, H

2015-05-01

Bacterial L-forms have always been considered as osmotic-pressure-sensitive cell-wall-deficient bacteria and isolation culture of L-forms must use media with high osmotic pressure. However, isolation culture of stable L-forms formed in humans and animals is very difficult because they have adapted to the physiological osmotic pressure condition of the host. We use a non-high osmotic isolation technique to isolate stable L-forms of Salmonella Typhi and Salmonella Paratyphi A from bile-inducer cultures in vitro and from patients' gallbladder specimens. Multiplex PCR assay for Salmonella-specific genes and nucleotide sequencing are used to identify the Salmonella L-forms in stable L-form isolates. Using this method, we confirmed that Salmonella Paratyphi A and Salmonella Typhi cannot be isolated from bile-inducer cultures cultured for 6 h or 48 h, but the L-forms can be isolated from 1 h to 45 days. In the 524 gallbladder samples, the positive rate for bacterial forms was 19.7% and the positive rate for Salmonella spp. was 0.6% by routine bacteriological methods. The positive rate for bacterial L-forms was 75.4% using non-high osmotic isolation culture. In the L-form isolates, the positive rate of Salmonella invA gene was 3.1%. In these invA-positive L-form isolates, four were positive for the invA and flic-d genes of Salmonella Typhi, and ten were positive for the invA and flic-a genes of Salmonella Paratyphi A. Copyright © 2014 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

Characterization of Salmonella enterica Derivatives Harboring Defined aroC and Salmonella Pathogenicity Island 2 Type III Secretion System (ssaV) Mutations by Immunization of Healthy Volunteers

PubMed Central

Hindle, Zoë; Chatfield, Steven N.; Phillimore, Jo; Bentley, Matthew; Johnson, Julie; Cosgrove, Catherine A.; Ghaem-Maghami, Marjan; Sexton, Amy; Khan, Mohammad; Brennan, Frank R.; Everest, Paul; Wu, Tao; Pickard, Derek; Holden, David W.; Dougan, Gordon; Griffin, George E.; House, Deborah; Santangelo, Joseph D.; Khan, Shahid A.; Shea, Jaqueline E.; Feldman, Robert G.; Lewis, David J. M.

2002-01-01

The attenuation and immunogenicity of two novel Salmonella vaccine strains, Salmonella enterica serovar Typhi (Ty2 ΔaroC ΔssaV, designated ZH9) and S. enterica serovar Typhimurium (TML ΔaroC ΔssaV, designated WT05), were evaluated after their oral administration to volunteers as single escalating doses of 107, 108, or 109 CFU. ZH9 was well tolerated, not detected in blood, nor persistently excreted in stool. Six of nine volunteers elicited anti-serovar Typhi lipopolysaccharide (LPS) immunoglobulin A (IgA) antibody-secreting cell (ASC) responses, with three of three vaccinees receiving 108 and two of three receiving 109 CFU which elicited high-titer LPS-specific serum IgG. WT05 was also well tolerated with no diarrhea, although the administration of 108 and 109 CFU resulted in shedding in stools for up to 23 days. Only volunteers immunized with 109 CFU of WT05 mounted detectable serovar Typhimurium LPS-specific ASC responses and serum antibody responses were variable. These data indicate that mutations in type III secretion systems may provide a route to the development of live vaccines in humans and highlight significant differences in the potential use of serovars Typhimurium and Typhi. PMID:12065485

Diversity of Salmonella enterica serovar Typhi strains collected from india using variable number tandem repeat (VNTR)-PCR analysis.

PubMed

Sankar, Sathish; Kuppanan, Suresh; Nandagopal, Balaji; Sridharan, Gopalan

2013-08-01

Typhoid fever is endemic in India, and a seasonal increase of cases is observed annually. In spite of effective therapies and the availability of vaccines, morbidity is widespread owing to the circulation of multiple genetic variants, frequent migration of asymptomatic carriers, unhygienic food practices and the emergence of multidrug resistance and thus continues to be a major public health problem in developing countries, particularly in India. Classical methods of strain typing such as pulsed-field gel electrophoresis, ribotyping, random amplification of polymorphic DNA and amplified fragment length polymorphism are either laborious and technically complicated or less discriminatory. We investigated the molecular diversity of Indian strains of Salmonella enterica serovar Typhi (S. Typhi) isolated from humans from different parts of India to establish the molecular epidemiology of the organism using the variable number tandem repeat (VNTR)-PCR analysis. The electrophoretic band pattern was analysed using the GelCompar II software program. Of the 94 strains tested for three VNTRs loci, 75 VNTR genotypes were obtained. Of the three VNTRs tested in this study, VNTR1 was amplified in all the strains except one and found to be predominant. VNTR2 was amplified only in 57 strains with a Simpson diversity index of 0.93 indicating the high variability of this region within the strains. VNTR3 was amplified in 90 strains. The discriminatory power of this typing tool has been greatly enhanced by this VNTR2 region as the other two regions could not discriminate strains significantly. In our study, about 55 % of the strains amplified all three VNTR regions and 39 % of the strains lacked the VNTR2 region. Among the three VNTR regions tested, the majority of the strains produced similar banding pattern for any two regions grouped into a cluster. The strains grouped as a genotype were from the same geographical location. Strains collected from each geographical region were also

Variable Number of Tandem Repeats in Salmonella enterica subsp. enterica for Typing Purposes

PubMed Central

Ramisse, Vincent; Houssu, Perrine; Hernandez, Eric; Denoeud, France; Hilaire, Valérie; Lisanti, Olivier; Ramisse, Françoise; Cavallo, Jean-Didier; Vergnaud, Gilles

2004-01-01

The genomic sequences of Salmonella enterica subsp. enterica strains CT18, Ty2 (serovar Typhi), and LT2 (serovar Typhimurium) were analyzed for potential variable number tandem repeats (VNTRs). A multiple-locus VNTR analysis (MLVA) of 99 strains of S. enterica supsp. enterica based on 10 VNTRs distinguished 52 genotypes and placed them into four groups. All strains tested were independent human isolates from France and did not reflect isolates from outbreak episodes. Of these 10 VNTRs, 7 showed variability within serovar Typhi, whereas 1 showed variability within serovar Typhimurium. Four VNTRs showed high Nei's diversity indices (DIs) of 0.81 to 0.87 within serovar Typhi (n = 27). Additionally, three of these more variable VNTRs showed DIs of 0.18 to 0.58 within serovar Paratyphi A (n = 10). The VNTR polymorphic site within multidrug-resistant (MDR) serovar Typhimurium isolates (n = 39; resistance to ampicillin, chloramphenicol, spectinomycin, sulfonamides, and tetracycline) showed a DI of 0.81. Cluster analysis not only identified three genetically distinct groups consistent with the present serovar classification of salmonellae (serovars Typhi, Paratyphi A, and Typhimurium) but also discriminated 25 subtypes (93%) within serovar Typhi isolates. The analysis discriminated only eight subtypes within serovar Typhimurium isolates resistant to ampicillin, chloramphenicol, spectinomycin, sulfonamides, and tetracycline, possibly reflecting the emergence in the mid-1990s of the DT104 phage type, which often displays such an MDR spectrum. Coupled with the ongoing improvements in automated procedures offered by capillary electrophoresis, use of these markers is proposed in further investigations of the potential of MLVA in outbreaks of salmonellosis, especially outbreaks of typhoid fever. PMID:15583305

Invasive Salmonella Infections in Areas of High and Low Malaria Transmission Intensity in Tanzania

PubMed Central

Biggs, Holly M.; Lester, Rebecca; Nadjm, Behzad; Mtove, George; Todd, Jim E.; Kinabo, Grace D.; Philemon, Rune; Amos, Ben; Morrissey, Anne B.; Reyburn, Hugh; Crump, John A.

2014-01-01

Background. The epidemiology of Salmonella Typhi and invasive nontyphoidal Salmonella (NTS) differs, and prevalence of these pathogens among children in sub-Saharan Africa may vary in relation to malaria transmission intensity. Methods. We compared the prevalence of bacteremia among febrile pediatric inpatients aged 2 months to 13 years recruited at sites of high and low malaria endemicity in Tanzania. Enrollment at Teule Hospital, the high malaria transmission site, was from June 2006 through May 2007, and at Kilimanjaro Christian Medical Centre (KCMC), the low malaria transmission site, from September 2007 through August 2008. Automated blood culture, malaria microscopy with Giemsa-stained blood films, and human immunodeficiency virus testing were performed. Results. At Teule, 3639 children were enrolled compared to 467 at KCMC. Smear-positive malaria was detected in 2195 of 3639 (60.3%) children at Teule and 11 of 460 (2.4%) at KCMC (P < .001). Bacteremia was present in 336 of 3639 (9.2%) children at Teule and 20 of 463 (4.3%) at KCMC (P < .001). NTS was isolated in 162 of 3639 (4.5%) children at Teule and 1 of 463 (0.2%) at KCMC (P < .001). Salmonella Typhi was isolated from 11 (0.3%) children at Teule and 6 (1.3%) at KCMC (P = .008). With NTS excluded, the prevalence of bacteremia at Teule was 5.0% and at KCMC 4.1% (P = .391). Conclusions. Where malaria transmission was intense, invasive NTS was common and Salmonella Typhi was uncommon, whereas the inverse was observed at a low malaria transmission site. The relationship between these pathogens, the environment, and the host is a compelling area for further research. PMID:24336909

Comparative evaluation of two Rickettsia typhi-specific quantitative real-time PCRs for research and diagnostic purposes.

PubMed

Papp, Stefanie; Rauch, Jessica; Kuehl, Svenja; Richardt, Ulricke; Keller, Christian; Osterloh, Anke

2017-02-01

Rickettsioses are caused by intracellular bacteria of the family of Rickettsiaceae. Rickettsia (R.) typhi is the causative agent of endemic typhus. The disease occurs worldwide and is one of the most prevalent rickettsioses. Rickettsial diseases, however, are generally underdiagnosed which is mainly due to the lack of sensitive and specific methods. In addition, methods for quantitative detection of the bacteria for research purposes are rare. We established two qPCRs for the detection of R. typhi by amplification of the outer membrane protein B (ompB) and parvulin-type PPIase (prsA) genes. Both qPCRs are specific and exclusively recognize R. typhi but no other rickettsiae including the closest relative, R. prowazekii. The prsA-based qPCR revealed to be much more sensitive than the amplification of ompB and provided highly reproducible results in the detection of R. typhi in organs of infected mice. Furthermore, as a nested PCR the prsA qPCR was applicable for the detection of R. typhi in human blood samples. Collectively, the prsA-based qPCR represents a reliable method for the quantitative detection of R. typhi for research purposes and is a promising candidate for differential diagnosis.

Immunization with the conjugate vaccine Vi-CRM₁₉₇ against Salmonella typhi induces Vi-specific mucosal and systemic immune responses in mice.

PubMed

Fiorino, Fabio; Ciabattini, Annalisa; Rondini, Simona; Pozzi, Gianni; Martin, Laura B; Medaglini, Donata

2012-09-21

Typhoid fever is a public health problem, especially among young children in developing countries. To address this need, a glycoconjugate vaccine Vi-CRM₁₉₇, composed of the polysaccharide antigen Vi covalently conjugated to the non-toxic mutant of diphtheria toxin CRM₁₉₇, is under development. Here, we assessed the antibody and cellular responses, both local and systemic, following subcutaneous injection of Vi-CRM₁₉₇. The glycoconjugate elicited Vi-specific serum IgG titers significantly higher than unconjugated Vi, with prevalence of IgG1 that persisted for at least 60 days after immunization. Vi-specific IgG, but not IgA, were present in intestinal washes. Lymphocytes proliferation after restimulation with Vi-CRM₁₉₇ was observed in spleen and mesenteric lymph nodes. These data confirm the immunogenicity of Vi-CRM₁₉₇ and demonstrate that the vaccine-specific antibody and cellular immune responses are present also in the intestinal tract, thus strengthening the suitability of Vi-CRM₁₉₇ as a promising candidate vaccine against Salmonella Typhi. Copyright © 2012 Elsevier Ltd. All rights reserved.

Clinical and serological responses following primary and booster immunization with Salmonella typhi Vi capsular polysaccharide vaccines.

PubMed

Keitel, W A; Bond, N L; Zahradnik, J M; Cramton, T A; Robbins, J B

1994-01-01

Clinical and serum antibody responses following intramuscular injection of two formulations of Salmonella typhi Vi capsular polysaccharide (Vi) were assessed in a double-blind evaluation. Healthy adults were randomly assigned to receive a 25 micrograms dose of liquid (Vi-Liq; n = 182) or freeze-dried Vi vaccine (Vi-Lyoph; n = 55), or placebo (n = 86). Erythema and/or induration > or = 1 cm in diameter at the injection site developed in 13/182 (7%) of Vi-Liq and 3/55 (5%) of Vi-Lyoph recipients (not significant, n.s.). Fever (oral temperature > or = 100 degrees F (37.8 degrees C)) occurred in < 2% of vaccinees. The frequencies of rises of fourfold or greater and of maximal Vi antibody levels were similar in the two vaccine groups. Fourfold or greater rises in serum Vi antibody levels (RIA) developed in 53% of Vi-Lyoph and 60% of Vi-Liq recipients by 1 week (n.s.), and 98 and 93%, respectively, by 1 month (n.s.). The frequencies of adverse reactions and mean Vi antibody levels following booster immunization with Vi-Liq 27 to 34 months after primary immunization (n = 55) were similar to those observed following primary immunization, although subjects given a booster dose were more likely to develop local reactions > or = 1 cm in diameter than those given a first dose (10/55 versus 13/182, p = 0.013 by the chi 2 test). Primary and booster immunizations with the Vi vaccines are well tolerated in healthy adults; mean Vi antibody levels remain significantly elevated for up to 34 months after primary immunization.

The influence of conjugation variables on the design and immunogenicity of a glycoconjugate vaccine against Salmonella Typhi

PubMed Central

Arcuri, M.; Di Benedetto, R.; Cunningham, A. F.; Saul, A.; MacLennan, C. A.

2017-01-01

In recent years there have been major efforts to develop glycoconjugate vaccines based on the Vi polysaccharide that will protect against Salmonella enterica Typhi infections, particularly typhoid fever, which remains a major public health concern in low-income countries. The design of glycoconjugate vaccines influences the immune responses they elicit. Here we systematically test the response in mice to Vi glycoconjugates that differ in Vi chain length (full-length and fragmented), carrier protein, conjugation chemistry, saccharide to protein ratio and size. We show that the length of Vi chains, but not the ultimate size of the conjugate, has an impact on the anti-Vi IgG immune response induced. Full-length Vi conjugates, independent of the carrier protein, induce peak IgG responses rapidly after just one immunization, and secondary immunization does not enhance the magnitude of these responses. Fragmented Vi linked to CRM197 and diphtheria toxoid, but not to tetanus toxoid, gives lower anti-Vi antibody responses after the first immunization than full-length Vi conjugates, but antibody titres are similar to those induced by full-length Vi conjugates following a second dose. The chemistry to conjugate Vi to the carrier protein, the linker used, and the saccharide to protein ratio do not significantly alter the response. We conclude that Vi length and carrier protein are the variables that influence the anti-Vi IgG response to immunization the most, while other parameters are of lesser importance. PMID:29287062

Cross-protection against Salmonella enteritidis infection in mice. III. Delayed hypersensitivity reaction and clearance of the challenge organism.

PubMed

Padmanaban, V D; Mittal, K R

1979-01-01

Mice were immunized with live vaccines and with live vaccines with complete adjuvant incorporating Salmonella enteritidis, Salmonella typhi-murium, Salmonella gallinarum or Salmonella pullorum. On the 21st day after vacination, the hypersensitivity reactions elicited by the mice to extracts of the challenge organism (S. enteritidis 5694 SMR) were assessed. The degree of delayed hypersensitivity reaction was compared with the level of protection induced by the vaccine. The role in protection of delayed hypersensitivity is discussed. Clearance of the challenge organism from the liver of previously vaccinated and unvaccinated mice was assessed quantitatively.

Shell-vial culture and real-time PCR applied to Rickettsia typhi and Rickettsia felis detection.

PubMed

Segura, Ferran; Pons, Immaculada; Pla, Júlia; Nogueras, María-Mercedes

2015-11-01

Murine typhus is a zoonosis transmitted by fleas, whose etiological agent is Rickettsia typhi. Rickettsia felis infection can produces similar symptoms. Both are intracellular microorganisms. Therefore, their diagnosis is difficult and their infections can be misdiagnosed. Early diagnosis prevents severity and inappropriate treatment regimens. Serology can't be applied during the early stages of infection because it requires seroconversion. Shell-vial (SV) culture assay is a powerful tool to detect Rickettsia. The aim of the study was to optimize SV using a real-time PCR as monitoring method. Moreover, the study analyzes which antibiotics are useful to isolate these microorganisms from fleas avoiding contamination by other bacteria. For the first purpose, SVs were inoculated with each microorganism. They were incubated at different temperatures and monitored by real-time PCR and classical methods (Gimenez staining and indirect immunofluorescence assay). R. typhi grew at all temperatures. R. felis grew at 28 and 32 °C. Real-time PCR was more sensitive than classical methods and it detected microorganisms much earlier. Besides, the assay sensitivity was improved by increasing the number of SV. For the second purpose, microorganisms and fleas were incubated and monitored in different concentrations of antibiotics. Gentamicin, sufamethoxazole, trimethoprim were useful for R. typhi isolation. Gentamicin, streptomycin, penicillin, and amphotericin B were useful for R. felis isolation. Finally, the optimized conditions were used to isolate R. felis from fleas collected at a veterinary clinic. R. felis was isolated at 28 and 32 °C. However, successful establishment of cultures were not possible probably due to sub-optimal conditions of samples.

SEROTYPING AND ANTIMICROBIAL DRUG RESISTANCE OF SALMONELLA ISOLATED FROM LETTUCE AND HUMAN DIARRHEA SAMPLES IN BURKINA FASO.

PubMed Central

Siourimè, Somda Namwin; Isidore, Bonkoungou Ouindgueta Juste; Oumar, Traoré; Nestor, Bassolé Ismael Henri; Yves, Traoré; Nicolas, Barro; Aly, Savadogo

2017-01-01

Background: In Burkina Faso dirty water in particular those of the stoppings and the gutter ones are used for vegetables irrigation in the gardens. The aim of this study was to determine the prevalence and antibiotic susceptibility of Salmonella serotypes from humans and lettuce samples inBurkina Faso. Materials and Methods:Salmonella strains isolated from patients in 2009 to 2015 and lettuce samples in 2014 in Burkina Faso were serotyped using specific antisera. All strains were subjected to a set of 14 antibiotics to study their antibiogram by using Baeur–Kirby disk diffusion method. Results: Out of 154 Salmonella isolated, 60 were from human and 94 from lettuce samples. Serotyping revealed four different serotypes and 39% (60) untypeable strains from human and lettuce (14 and 46 strains). Salmonella serotypes from human and lettuce samples were: Paratyphi A (10% and 22%), Paratyphi B (34% and 8%), Paratyphi C (14% and 18%) and Typhi (21% and 1%). A high resistance of Salmonella Paratyphi B and Salmonella spp to tetracycline were 70% from human and 35 % from lettuce samples. Multiresistance was observed to tetracycline, chloramphenicol and amoxicillin/clavulanic-acid or ampicillin with Salmonella ParatyphiB 35% and Salmonella Typhi 33% from human samples and Salmonella spp 4% from lettuce samples. Conclusion: This study showed the diversity of Salmonella serotypes from both clinical and environmental samples and emergence of multiresistant Salmonella to antibiotics in Burkina Faso. A lettuce is a potential source of transmission of Salmonella causing diarrhea among human in Burkina Faso. List of non-standard Abbreviations : HDB: Hôpital du District de Bogodogo, LNSP: Laboratoire National de Santé Publique, DSG : District Sanitaire de Gourcy, DSB : District Sanitaire de Boromo PMID:28670637

Molecular epidemiology of fluoroquinolone resistant Salmonella in Africa: A systematic review and meta-analysis

PubMed Central

Tessema, Tesfaye S.; Beyene, Getenet; Aseffa, Abraham

2018-01-01

Background Wide-ranging evidence on the occurrence of fluoroquinolone (FQ) resistance genetic determinants in African Salmonella strains is not available. The main objectives of this study were to assess the heterogeneity, estimate pooled proportions and describe the preponderance of FQ-resistance determinants in typhoidal and non-typhoidal Salmonella (NTS) isolates of Africa. Methods Genetic and phenotypic data on 6103 Salmonella isolates were considered. Meta- and frequency analyses were performed depending on the number of studies by category, number of isolates and risks of bias. A random effects model was used to assess heterogeneity and estimate pooled proportions. Relative and cumulative frequencies were calculated to describe the overall preponderance of FQ-resistance determinants in quinolone resistant isolates. Results The pooled proportion of gyrA mutants (Salmonella enterica serovar Typhi, Salmonella enterica serovar Typhimurium, and Salmonella enterica serovar Enteritidis) was estimated at 5.7% (95% Confidence interval (CI) = 2.6, 9.8; Tau squared (T2) = 0.1105), and was higher in S. Typhi than in S. Typhimurium (odds ratio (OR) = 3.3, 95%CI = 2, 5.7). The proportions of each of gyrB and parC mutants, and strains with Plasmid Mediated Quinolone Resistance genes (qnrA, qnrB and qnrS) were low (≤ 0.3%). Overall, 23 mutant serotypes were identified, and most strains had mutations at codons encoding Ser83 and Asp87 of gyrA (82%, 95%CI = 78, 86). Conclusions Mutations at gyrA appear to account for ciprofloxacin non-susceptibility in most clinical Salmonella strains in Africa. The estimates could be harnessed to develop a mismatch-amplification mutation-assay for the detection of FQ-resistant strains in Africa. PMID:29432492

Molecular epidemiology of fluoroquinolone resistant Salmonella in Africa: A systematic review and meta-analysis.

PubMed

Tadesse, Getachew; Tessema, Tesfaye S; Beyene, Getenet; Aseffa, Abraham

2018-01-01

Wide-ranging evidence on the occurrence of fluoroquinolone (FQ) resistance genetic determinants in African Salmonella strains is not available. The main objectives of this study were to assess the heterogeneity, estimate pooled proportions and describe the preponderance of FQ-resistance determinants in typhoidal and non-typhoidal Salmonella (NTS) isolates of Africa. Genetic and phenotypic data on 6103 Salmonella isolates were considered. Meta- and frequency analyses were performed depending on the number of studies by category, number of isolates and risks of bias. A random effects model was used to assess heterogeneity and estimate pooled proportions. Relative and cumulative frequencies were calculated to describe the overall preponderance of FQ-resistance determinants in quinolone resistant isolates. The pooled proportion of gyrA mutants (Salmonella enterica serovar Typhi, Salmonella enterica serovar Typhimurium, and Salmonella enterica serovar Enteritidis) was estimated at 5.7% (95% Confidence interval (CI) = 2.6, 9.8; Tau squared (T2) = 0.1105), and was higher in S. Typhi than in S. Typhimurium (odds ratio (OR) = 3.3, 95%CI = 2, 5.7). The proportions of each of gyrB and parC mutants, and strains with Plasmid Mediated Quinolone Resistance genes (qnrA, qnrB and qnrS) were low (≤ 0.3%). Overall, 23 mutant serotypes were identified, and most strains had mutations at codons encoding Ser83 and Asp87 of gyrA (82%, 95%CI = 78, 86). Mutations at gyrA appear to account for ciprofloxacin non-susceptibility in most clinical Salmonella strains in Africa. The estimates could be harnessed to develop a mismatch-amplification mutation-assay for the detection of FQ-resistant strains in Africa.

The Ecological Dynamics of Fecal Contamination and Salmonella Typhi and Salmonella Paratyphi A in Municipal Kathmandu Drinking Water

PubMed Central

Walker, Alan W.; Thompson, Corinne N.; Torres, Andres; Dongol, Sabina; Tran Vu Thieu, Nga; Pham Thanh, Duy; Tran Thi Ngoc, Dung; Voong Vinh, Phat; Singer, Andrew C.; Parkhill, Julian; Thwaites, Guy; Basnyat, Buddha; Ferguson, Neil; Baker, Stephen

2016-01-01

One of the UN sustainable development goals is to achieve universal access to safe and affordable drinking water by 2030. It is locations like Kathmandu, Nepal, a densely populated city in South Asia with endemic typhoid fever, where this goal is most pertinent. Aiming to understand the public health implications of water quality in Kathmandu we subjected weekly water samples from 10 sources for one year to a range of chemical and bacteriological analyses. We additionally aimed to detect the etiological agents of typhoid fever and longitudinally assess microbial diversity by 16S rRNA gene surveying. We found that the majority of water sources exhibited chemical and bacterial contamination exceeding WHO guidelines. Further analysis of the chemical and bacterial data indicated site-specific pollution, symptomatic of highly localized fecal contamination. Rainfall was found to be a key driver of this fecal contamination, correlating with nitrates and evidence of S. Typhi and S. Paratyphi A, for which DNA was detectable in 333 (77%) and 303 (70%) of 432 water samples, respectively. 16S rRNA gene surveying outlined a spectrum of fecal bacteria in the contaminated water, forming complex communities again displaying location-specific temporal signatures. Our data signify that the municipal water in Kathmandu is a predominant vehicle for the transmission of S. Typhi and S. Paratyphi A. This study represents the first extensive spatiotemporal investigation of water pollution in an endemic typhoid fever setting and implicates highly localized human waste as the major contributor to poor water quality in the Kathmandu Valley. PMID:26735696

The Ecological Dynamics of Fecal Contamination and Salmonella Typhi and Salmonella Paratyphi A in Municipal Kathmandu Drinking Water.

PubMed

Karkey, Abhilasha; Jombart, Thibaut; Walker, Alan W; Thompson, Corinne N; Torres, Andres; Dongol, Sabina; Tran Vu Thieu, Nga; Pham Thanh, Duy; Tran Thi Ngoc, Dung; Voong Vinh, Phat; Singer, Andrew C; Parkhill, Julian; Thwaites, Guy; Basnyat, Buddha; Ferguson, Neil; Baker, Stephen

2016-01-01

One of the UN sustainable development goals is to achieve universal access to safe and affordable drinking water by 2030. It is locations like Kathmandu, Nepal, a densely populated city in South Asia with endemic typhoid fever, where this goal is most pertinent. Aiming to understand the public health implications of water quality in Kathmandu we subjected weekly water samples from 10 sources for one year to a range of chemical and bacteriological analyses. We additionally aimed to detect the etiological agents of typhoid fever and longitudinally assess microbial diversity by 16S rRNA gene surveying. We found that the majority of water sources exhibited chemical and bacterial contamination exceeding WHO guidelines. Further analysis of the chemical and bacterial data indicated site-specific pollution, symptomatic of highly localized fecal contamination. Rainfall was found to be a key driver of this fecal contamination, correlating with nitrates and evidence of S. Typhi and S. Paratyphi A, for which DNA was detectable in 333 (77%) and 303 (70%) of 432 water samples, respectively. 16S rRNA gene surveying outlined a spectrum of fecal bacteria in the contaminated water, forming complex communities again displaying location-specific temporal signatures. Our data signify that the municipal water in Kathmandu is a predominant vehicle for the transmission of S. Typhi and S. Paratyphi A. This study represents the first extensive spatiotemporal investigation of water pollution in an endemic typhoid fever setting and implicates highly localized human waste as the major contributor to poor water quality in the Kathmandu Valley.

Case report: failure under azithromycin treatment in a case of bacteremia due to Salmonella enterica Paratyphi A.

PubMed

Kobayashi, Tetsuro; Hayakawa, Kayoko; Mawatari, Momoko; Mezaki, Kazuhisa; Takeshita, Nozomi; Kutsuna, Satoshi; Fujiya, Yoshihiro; Kanagawa, Shuzo; Ohmagari, Norio; Kato, Yasuyuki; Morita, Masatomo

2014-07-20

Limited information is available regarding the clinical efficacy of azithromycin for the treatment of enteric fever due to fluoroquinolone-resistant Salmonella Typhi and Salmonella Paratyphi among travelers returning to their home countries. We report a case of a 52-year-old Japanese man who returned from India, who developed a fever of 39°C with no accompanying symptoms 10 days after returning to Japan from a 1-month business trip to Delhi, India. His blood culture results were positive for Salmonella Paratyphi A. He was treated with 14 days of ceftriaxone, after which he remained afebrile for 18 days before his body temperature again rose to 39°C with no apparent symptoms. He was then empirically given 500 mg of azithromycin, but experienced clinical and microbiological failure of azithromycin treatment for enteric fever due to Salmonella Paratyphi A. However, the minimum inhibitory concentration (MIC) of azithromycin was not elevated (8 mg/L). He was again given ceftriaxone for 14 days with no signs of recurrence during the follow-up. There are limited data available for the treatment of enteric fever using azithromycin in travelers from developed countries who are not immune to the disease, and thus, careful follow-up is necessary. In our case, the low azithromycin dose might have contributed the treatment failure. Additional clinical data are needed to determine the rate of success, MIC, and contributing factors for success and/or failure of azithromycin treatment for both Salmonella Typhi and Salmonella Paratyphi infections.

Baseline Antibody Titre against Salmonella enterica in Healthy Population of Mumbai, Maharashtra, India.

PubMed

Patki, Rucha; Lilani, Sunil; Lanjewar, Dhaneshwar

2017-01-01

The aim of this study was to establish a baseline titre for the population of Mumbai, Maharashtra, India. Four hundred healthy blood donors, attending blood donation camps, were screened using a survey questionnaire. Widal tube agglutination test was performed on the diluted sera (with 0.9% normal saline) of blood donors, with final dilution ranging from 1 : 40 to 1 : 320. Out of 400 individuals providing samples, 78 (19.5%) individuals showed antibody titres ≥ 1 : 40 for at least one antigen and 322 (80.5%) showed no agglutination. The baseline antibody titres against O antigen and H antigen of Salmonella enterica serotype Typhi were found to be 1 : 40 and 1 : 80, respectively. Similarly, the baseline antibody titres for the H antigen of Salmonella enterica serotypes Paratyphi A and Paratyphi B were found to be 1 : 40 and 1 : 80, respectively. Thus, it was noted that the diagnostically significant cutoff of antibody titre from acute phase sample was ≥ 1 : 80 for S. Typhi O antigen and titre of ≥ 1 : 160 for both S. Typhi H antigen and S. Paratyphi BH antigen. Antibody titre of ≥ 1 : 80 can be considered significant for S. Paratyphi AH antigen.

Baseline Antibody Titre against Salmonella enterica in Healthy Population of Mumbai, Maharashtra, India

PubMed Central

Lilani, Sunil; Lanjewar, Dhaneshwar

2017-01-01

Objective The aim of this study was to establish a baseline titre for the population of Mumbai, Maharashtra, India. Method Four hundred healthy blood donors, attending blood donation camps, were screened using a survey questionnaire. Widal tube agglutination test was performed on the diluted sera (with 0.9% normal saline) of blood donors, with final dilution ranging from 1 : 40 to 1 : 320. Results Out of 400 individuals providing samples, 78 (19.5%) individuals showed antibody titres ≥ 1 : 40 for at least one antigen and 322 (80.5%) showed no agglutination. The baseline antibody titres against O antigen and H antigen of Salmonella enterica serotype Typhi were found to be 1 : 40 and 1 : 80, respectively. Similarly, the baseline antibody titres for the H antigen of Salmonella enterica serotypes Paratyphi A and Paratyphi B were found to be 1 : 40 and 1 : 80, respectively. Conclusion Thus, it was noted that the diagnostically significant cutoff of antibody titre from acute phase sample was ≥ 1 : 80 for S. Typhi O antigen and titre of ≥ 1 : 160 for both S. Typhi H antigen and S. Paratyphi BH antigen. Antibody titre of ≥ 1 : 80 can be considered significant for S. Paratyphi AH antigen. PMID:29081804

Crystal structure of an antigenic outer-membrane protein from Salmonella Typhi suggests a potential antigenic loop and an efflux mechanism.

PubMed

Guan, Hong-Hsiang; Yoshimura, Masato; Chuankhayan, Phimonphan; Lin, Chien-Chih; Chen, Nai-Chi; Yang, Ming-Chi; Ismail, Asma; Fun, Hoong-Kun; Chen, Chun-Jung

2015-11-13

ST50, an outer-membrane component of the multi-drug efflux system from Salmonella enterica serovar Typhi, is an obligatory diagnostic antigen for typhoid fever. ST50 is an excellent and unique diagnostic antigen with 95% specificity and 90% sensitivity and is used in the commercial diagnosis test kit (TYPHIDOT(TM)). The crystal structure of ST50 at a resolution of 2.98 Å reveals a trimer that forms an α-helical tunnel and a β-barrel transmembrane channel traversing the periplasmic space and outer membrane. Structural investigations suggest significant conformational variations in the extracellular loop regions, especially extracellular loop 2. This is the location of the most plausible antibody-binding domain that could be used to target the design of new antigenic epitopes for the development of better diagnostics or drugs for the treatment of typhoid fever. A molecule of the detergent n-octyl-β-D-glucoside is observed in the D-cage, which comprises three sets of Asp361 and Asp371 residues at the periplasmic entrance. These structural insights suggest a possible substrate transport mechanism in which the substrate first binds at the periplasmic entrance of ST50 and subsequently, via iris-like structural movements to open the periplasmic end, penetrates the periplasmic domain for efflux pumping of molecules, including poisonous metabolites or xenobiotics, for excretion outside the pathogen.

Structural and functional studies of a 50 kDa antigenic protein from Salmonella enterica serovar Typhi.

PubMed

Choong, Yee Siew; Lim, Theam Soon; Chew, Ai Lan; Aziah, Ismail; Ismail, Asma

2011-04-01

The high typhoid incidence rate in developing and under-developed countries emphasizes the need for a rapid, affordable and accessible diagnostic test for effective therapy and disease management. TYPHIDOT®, a rapid dot enzyme immunoassay test for typhoid, was developed from the discovery of a ∼50 kDa protein specific for Salmonella enterica serovar Typhi. However, the structure of this antigen remains unknown till today. Studies on the structure of this antigen are important to elucidate its function, which will in turn increase the efficiency of the development and improvement of the typhoid detection test. This paper described the predictive structure and function of the antigenically specific protein. The homology modeling approach was employed to construct the three-dimensional structure of the antigen. The built structure possesses the features of TolC-like outer membrane protein. Molecular docking simulation was also performed to further probe the functionality of the antigen. Docking results showed that hexamminecobalt, Co(NH(3))(6)(3+), as an inhibitor of TolC protein, formed favorable hydrogen bonds with D368 and D371 of the antigen. The single point (D368A, D371A) and double point (D368A and D371A) mutations of the antigen showed a decrease (single point mutation) and loss (double point mutations) of binding affinity towards hexamminecobalt. The architecture features of the built model and the docking simulation reinforced and supported that this antigen is indeed the variant of outer membrane protein, TolC. As channel proteins are important for the virulence and survival of bacteria, therefore this ∼50 kDa channel protein is a good specific target for typhoid detection test. Copyright © 2011 Elsevier Inc. All rights reserved.

Salmonella Bacteremia Among Children in Central and Northwest Nigeria, 2008–2015

PubMed Central

Obaro, Stephen K.; Hassan-Hanga, Fatimah; Olateju, Eyinade K.; Umoru, Dominic; Lawson, Lovett; Olanipekun, Grace; Ibrahim, Sadeeq; Munir, Huda; Ihesiolor, Gabriel; Maduekwe, Augustine; Ohiaeri, Chinatu; Adetola, Anthony; Shetima, Denis; Jibir, Binta W.; Nakaura, Hafsat; Kocmich, Nicholas; Ajose, Therasa; Idiong, David; Masokano, Kabir; Ifabiyi, Adeyemi; Ihebuzor, Nnenna; Chen, Baojiang; Meza, Jane; Akindele, Adebayo; Rezac-Elgohary, Amy; Olaosebikan, Rasaq; Suwaid, Salman; Gambo, Mahmoud; Alter, Roxanne; Davies, Herbert D.; Fey, Paul D.

2015-01-01

Background. Etiologic agents of childhood bacteremia remain poorly defined in Nigeria. The absence of such data promotes indiscriminate use of antibiotics and delays implementation of appropriate preventive strategies. Methods. We established diagnostic laboratories for bacteremia surveillance at regional sites in central and northwest Nigeria. Acutely ill children aged <5 years with clinically suspected bacteremia were evaluated at rural and urban clinical facilities in the Federal Capital Territory, central region and in Kano, northwest Nigeria. Blood was cultured using the automated Bactec incubator system. Results. Between September 2008 and April 2015, we screened 10 133 children. Clinically significant bacteremia was detected in 609 of 4051 (15%) in the northwest and 457 of 6082 (7.5%) in the central region. Across both regions, Salmonella species account for 24%–59.8% of bacteremias and are the commonest cause of childhood bacteremia, with a predominance of Salmonella enterica serovar Typhi. The prevalence of resistance to ampicillin, chloramphenicol, and cotrimoxazole was 38.11%, with regional differences in susceptibility to different antibiotics but high prevalence of resistance to readily available oral antibiotics. Conclusions. Salmonella Typhi is the leading cause of childhood bacteremia in central Nigeria. Expanded surveillance is planned to define the dynamics of transmission. The high prevalence of multidrug-resistant strains calls for improvement in environmental sanitation in the long term and vaccination in the short term. PMID:26449948

Expression and function of S100A8/A9 (calprotectin) in human typhoid fever and the murine Salmonella model.

PubMed

De Jong, Hanna K; Achouiti, Ahmed; Koh, Gavin C K W; Parry, Christopher M; Baker, Stephen; Faiz, Mohammed Abul; van Dissel, Jaap T; Vollaard, Albert M; van Leeuwen, Ester M M; Roelofs, Joris J T H; de Vos, Alex F; Roth, Johannes; van der Poll, Tom; Vogl, Thomas; Wiersinga, Willem Joost

2015-04-01

Typhoid fever, caused by the Gram-negative bacterium Salmonella enterica serovar Typhi, is a major cause of community-acquired bacteremia and death worldwide. S100A8 (MRP8) and S100A9 (MRP14) form bioactive antimicrobial heterodimers (calprotectin) that can activate Toll-like receptor 4, promoting lethal, endotoxin-induced shock and multi-organ failure. We aimed to characterize the expression and function of S100A8/A9 in patients with typhoid fever and in a murine invasive Salmonella model. S100A8/A9 protein levels were determined in acute phase plasma or feces from 28 Bangladeshi patients, and convalescent phase plasma from 60 Indonesian patients with blood culture or PCR-confirmed typhoid fever, and compared to 98 healthy control subjects. To functionally characterize the role of S100A8/A9, we challenged wildtype (WT) and S100A9-/- mice with S. Typhimurium and determined bacterial loads and inflammation 2- and 5- days post infection. We further assessed the antimicrobial function of recombinant S100A8/A9 on S. Typhimurium and S. Typhi replication in vitro. Typhoid fever patients demonstrated a marked increase of S100A8/A9 in acute phase plasma and feces and this increases correlated with duration of fever prior to admission. S100A8/A9 directly inhibited the growth of S. Typhimurium and S. Typhi in vitro in a dose and time dependent fashion. WT mice inoculated with S. Typhimurium showed increased levels of S100A8/A9 in both the liver and the systemic compartment but S100A9-/- mice were indistinguishable from WT mice with respect to bacterial growth, survival, and inflammatory responses, as determined by cytokine release, histopathology and organ injury. S100A8/A9 is markedly elevated in human typhoid, correlates with duration of fever prior to admission and directly inhibits the growth of S. Typhimurium and S. Typhi in vitro. Despite elevated levels in the murine invasive Salmonella model, S100A8/A9 does not contribute to an effective host response against S

Expression and Function of S100A8/A9 (Calprotectin) in Human Typhoid Fever and the Murine Salmonella Model

PubMed Central

De Jong, Hanna K.; Achouiti, Ahmed; Koh, Gavin C. K. W.; Parry, Christopher M.; Baker, Stephen; Faiz, Mohammed Abul; van Dissel, Jaap T.; Vollaard, Albert M.; van Leeuwen, Ester M. M.; Roelofs, Joris J. T. H.; de Vos, Alex F.; Roth, Johannes; van der Poll, Tom; Vogl, Thomas; Wiersinga, Willem Joost

2015-01-01

Background Typhoid fever, caused by the Gram-negative bacterium Salmonella enterica serovar Typhi, is a major cause of community-acquired bacteremia and death worldwide. S100A8 (MRP8) and S100A9 (MRP14) form bioactive antimicrobial heterodimers (calprotectin) that can activate Toll-like receptor 4, promoting lethal, endotoxin-induced shock and multi-organ failure. We aimed to characterize the expression and function of S100A8/A9 in patients with typhoid fever and in a murine invasive Salmonella model. Methods and principal findings S100A8/A9 protein levels were determined in acute phase plasma or feces from 28 Bangladeshi patients, and convalescent phase plasma from 60 Indonesian patients with blood culture or PCR-confirmed typhoid fever, and compared to 98 healthy control subjects. To functionally characterize the role of S100A8/A9, we challenged wildtype (WT) and S100A9-/- mice with S. Typhimurium and determined bacterial loads and inflammation 2- and 5- days post infection. We further assessed the antimicrobial function of recombinant S100A8/A9 on S. Typhimurium and S. Typhi replication in vitro. Typhoid fever patients demonstrated a marked increase of S100A8/A9 in acute phase plasma and feces and this increases correlated with duration of fever prior to admission. S100A8/A9 directly inhibited the growth of S. Typhimurium and S. Typhi in vitro in a dose and time dependent fashion. WT mice inoculated with S. Typhimurium showed increased levels of S100A8/A9 in both the liver and the systemic compartment but S100A9-/- mice were indistinguishable from WT mice with respect to bacterial growth, survival, and inflammatory responses, as determined by cytokine release, histopathology and organ injury. Conclusion S100A8/A9 is markedly elevated in human typhoid, correlates with duration of fever prior to admission and directly inhibits the growth of S. Typhimurium and S. Typhi in vitro. Despite elevated levels in the murine invasive Salmonella model, S100A8/A9 does not

Decreased ciprofloxacin susceptibility in Salmonella Typhi and Paratyphi infections in ill-returned travellers: the impact on clinical outcome and future treatment options.

PubMed

Hassing, R-J; Goessens, W H F; Mevius, D J; van Pelt, W; Mouton, J W; Verbon, A; van Genderen, P J

2013-10-01

The emergence of decreased ciprofloxacin susceptibility (DCS) in Salmonella enterica serovar Typhi and serovar Paratyphi A, B or C limits treatment options. We studied the impact of DCS isolates on the fate of travellers returning with enteric fever and possible alternative treatment options. We evaluated the clinical features, susceptibility data and efficacy of empirical treatment in patients with positive blood cultures of a DCS isolate compared to patients infected with a ciprofloxacin-susceptible (CS) isolate in the period from January 2002 to August 2008. In addition, the pharmacokinetic and pharmacodynamic parameters of ciprofloxacin, levofloxacin and gatifloxacin were determined to assess if increasing the dose would result in adequate unbound fraction of the drug 24-h area under the concentration-time curve/minimum inhibitory concentration (ƒAUC(0-24)/MIC) ratio. Patients with DCS more often returned from the Indian subcontinent and had a longer fever clearance time and length of hospital stay compared to patients in whom the initial empirical therapy was adequate. The mean ƒAUC(0-24)/MIC was 41.3 ± 18.8 in the patients with DCS and 585.4 ± 219 in patients with a CS isolate. For DCS isolates, the mean ƒAUC0-24/MIC for levofloxacin was 60.5 ± 28.7 and for gatifloxacin, it was 97.9 ± 28.0. Increasing the dose to an adequate ƒAUC(0-24)/MIC ratio will lead to conceivably toxic drug levels in 50% of the patients treated with ciprofloxacin. Emerging DCS isolates has led to the failure of empirical treatment in ill-returned travellers. We demonstrated that, in some cases, an adequate ƒAUC(0-24)/MIC ratio could be achieved by increasing the dose of ciprofloxacin or by the use of alternative fluoroquinolones.

Adaptation of red blood cell lysis represents a fundamental breakthrough that improves the sensitivity of Salmonella detection in blood

PubMed Central

Boyd, MA; Tennant, SM; Melendez, JH; Toema, D; Galen, JE; Geddes, CD; Levine, MM

2015-01-01

Aims Isolation of Salmonella Typhi from blood culture is the standard diagnostic for confirming typhoid fever but it is unavailable in many developing countries. We previously described a Microwave Accelerated Metal Enhanced Fluorescence (MAMEF)-based assay to detect Salmonella in medium. Attempts to detect Salmonella in blood were unsuccessful, presumably due to the interference of erythrocytes. The objective of this study was to evaluate various blood treatment methods that could be used prior to PCR, real-time PCR or MAMEF to increase sensitivity of detection of Salmonella. Methods and Results We tested ammonium chloride and erythrocyte lysis buffer, water, Lymphocyte Separation Medium, BD Vacutainer® CPT™ Tubes and dextran. Erythrocyte lysis buffer was the best isolation method as it is fast, inexpensive and works with either fresh or stored blood. The sensitivity of PCR- and real-time PCR detection of Salmonella in spiked blood was improved when whole blood was first lysed using erythrocyte lysis buffer prior to DNA extraction. Removal of erythrocytes and clotting factors also enabled reproducible lysis of Salmonella and fragmentation of DNA, which are necessary for MAMEF sensing. Conclusions Use of the erythrocyte lysis procedure prior to DNA extraction has enabled improved sensitivity of Salmonella detection by PCR and real-time PCR and has allowed lysis and fragmentation of Salmonella using microwave radiation (for future detection by MAMEF). Significance and Impact of the Study Adaptation of the blood lysis method represents a fundamental breakthrough that improves the sensitivity of DNA-based detection of Salmonella in blood. PMID:25630831

Comparative evaluation of two rapid Salmonella-IgM tests and blood culture in the diagnosis of enteric fever.

PubMed

Prasad, K J; Oberoi, J K; Goel, N; Wattal, C

2015-01-01

Enteric fever is a major public health problem in developing countries like India. An early and accurate diagnosis is necessary for a prompt and effective treatment. We have evaluated the diagnostic accuracy of two Rapid Salmonella-IgM tests (Typhidot-IgM and Enteroscreen-IgM) as compared to blood culture in rapid and early diagnosis of enteric fever. A total of 2,699 patients' serum samples were tested by Rapid Salmonella-IgM tests and blood culture. Patients were divided into two groups. Test group - patients with enteric fever and blood culture positives for Salmonella Typhi; and three types of Controls, i.e. patients with non-enteric fever illnesses, normal healthy controls and patients positive for S. Paratyphi- A. In addition to this we have also evaluated the significance of positive Salmonella-IgM tests among blood culture-negative cases. The overall sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of the Typhidot-IgM test and Enteroscreen-IgM test considering blood culture as gold standard were 97.29% and 88.13%, 97.40% and 87.83%, 98.18% and 92.03%, 96.15% and 82.27%, respectively. Typhidot-IgM test was found to be significantly more sensitive and specific as compared to Enteroscreen-IgM. Among blood culture-negative patients, Rapid Salmonella-IgM tests detected 72.25% additional cases of enteric fever. Although the Rapid Salmonella-IgM tests are meant to diagnose S. Typhi only, but these tests detect S. Paratyphi- A also. Thirty-eight patients who were blood culture-positive for S. Paratyphi- A were also positive by Rapid Salmonella-IgM tests. Rapid Salmonella-IgM tests offer an advantage of increased sensitivity, rapidity, early diagnosis and simplicity over blood culture.

The clinical and microbiological characteristics of enteric fever in Cambodia, 2008-2015

PubMed Central

Phe, Thong; Veng, Chhun H.; Lim, Kruy; Ieng, Sovann; Kham, Chun; Fawal, Nizar; Fabre, Laetitia; Le Hello, Simon; Vlieghe, Erika; Weill, François-Xavier; Jacobs, Jan; Peetermans, Willy E.

2017-01-01

Background Enteric fever remains a major public health problem in low resource settings and antibiotic resistance is increasing. In Asia, an increasing proportion of infections is caused by Salmonella enterica serovar Paratyphi A, which for a long time was assumed to cause a milder clinical syndrome compared to Salmonella enterica serovar Typhi. Methodology A retrospective chart review study was conducted of 254 unique cases of blood culture confirmed enteric fever who presented at a referral adult hospital in Phnom Penh, Cambodia between 2008 and 2015. Demographic, clinical and laboratory data were collected from clinical charts and antibiotic susceptibility testing was performed. Whole genome sequence analysis was performed on a subset of 121 isolates. Results One-hundred-and-ninety unique patients were diagnosed with Salmonella Paratyphi A and 64 with Salmonella Typhi. In the period 2008–2012, Salmonella Paratyphi A comprised 25.5% of 47 enteric fever cases compared to 86.0% of 207 cases during 2013–2015. Presenting symptoms were identical for both serovars but higher median leukocyte counts (6.8 x 109/L vs. 6.3 x 109/L; p = 0.035) and C-reactive protein (CRP) values (47.0 mg/L vs. 36 mg/L; p = 0.034) were observed for Salmonella Typhi infections. All but one of the Salmonella Typhi isolates belonged to haplotype H58 associated with multidrug resistance (MDR) (i.e. resistance to ampicillin, chloramphenicol and co-trimoxazole).;42.9% actually displayed MDR compared to none of the Salmonella Paratyphi A isolates. Decreased ciprofloxacin susceptibility (DCS) was observed in 96.9% (62/64) of Salmonella Typhi isolates versus 11.5% (21/183) of Salmonella Paratyphi A isolates (all but one from 2015). All isolates were susceptible to azithromycin and ceftriaxone. Conclusions In Phnom Penh, Cambodia, Salmonella Paratyphi A now causes the majority of enteric fever cases and decreased susceptibility against ciprofloxacin is increasing. Overall, Salmonella Typhi was

Integration of molecular dynamics simulation and hotspot residues grafting for de novo scFv design against Salmonella Typhi TolC protein.

PubMed

Leong, Siew Wen; Lim, Theam Soon; Ismail, Asma; Choong, Yee Siew

2018-05-01

With the development of de novo binders for protein targets from non-related scaffolds, many possibilities for therapeutics and diagnostics have been created. In this study, we described the use of de novo design approach to create single-chain fragment variable (scFv) for Salmonella enterica subspecies enterica serovar Typhi TolC protein. Typhoid fever is a global health concern in developing and underdeveloped countries. Rapid typhoid diagnostics will improve disease management and therapy. In this work, molecular dynamics simulation was first performed on a homology model of TolC protein in POPE membrane bilayer to obtain the central structure that was subsequently used as the target for scFv design. Potential hotspot residues capable of anchoring the binders to the target were identified by docking "disembodied" amino acid residues against TolC surface. Next, scFv scaffolds were selected from Protein Data Bank to harbor the computed hotspot residues. The hotspot residues were then incorporated into the scFv scaffold complementarity determining regions. The designs recapitulated binding energy, shape complementarity, and interface surface area of natural protein-antibody interfaces. This approach has yielded 5 designs with high binding affinity against TolC that may be beneficial for the future development of antigen-based detection agents for typhoid diagnostics. Copyright © 2017 John Wiley & Sons, Ltd.

O-Serotype Conversion in Salmonella Typhimurium Induces Protective Immune Responses against Invasive Non-Typhoidal Salmonella Infections.

PubMed

Li, Pei; Liu, Qing; Luo, Hongyan; Liang, Kang; Yi, Jie; Luo, Ying; Hu, Yunlong; Han, Yue; Kong, Qingke

2017-01-01

Salmonella infections remain a big problem worldwide, causing enteric fever by Salmonella Typhi (or Paratyphi) or self-limiting gastroenteritis by non-typhoidal Salmonella (NTS) in healthy individuals. NTS may become invasive and cause septicemia in elderly or immuno-compromised individuals, leading to high mortality and morbidity. No vaccines are currently available for preventing NTS infection in human. As these invasive NTS are restricted to several O-antigen serogroups including B1, D1, C1, and C2, O-antigen polysaccharide is believed to be a good target for vaccine development. In this study, a strategy of O-serotype conversion was investigated to develop live attenuated S . Typhimurium vaccines against the major serovars of NTS infections. The immunodominant O4 serotype of S . Typhimurium was converted into O9, O7, and O8 serotypes through unmarked chromosomal deletion-insertion mutations. O-serotype conversion was confirmed by LPS silver staining and western blotting. All O-serotype conversion mutations were successfully introduced into the live attenuated S . Typhimurium vaccine S738 (Δ crp Δ cya ) to evaluate their immunogenicity in mice model. The vaccine candidates induced high amounts of heterologous O-polysaccharide-specific functional IgG responses. Vaccinated mice survived a challenge of 100 times the 50% lethality dose (LD 50 ) of wild-type S . Typhimurium. Protective efficacy against heterologous virulent Salmonella challenges was highly O-serotype related. Furthermore, broad-spectrum protection against S . Typhimurium, S . Enteritidis, and S . Choleraesuis was observed by co-vaccination of O9 and O7 O-serotype-converted vaccine candidates. This study highlights the strategy of expressing heterologous O-polysaccharides via genetic engineering in developing live attenuated S . Typhimurium vaccines against NTS infections.

Attenuated Salmonella enterica serovar Typhi and Shigella flexneri 2a strains mucosally deliver DNA vaccines encoding measles virus hemagglutinin, inducing specific immune responses and protection in cotton rats.

PubMed

Pasetti, Marcela F; Barry, Eileen M; Losonsky, Genevieve; Singh, Mahender; Medina-Moreno, Sandra M; Polo, John M; Ulmer, Jeffrey; Robinson, Harriet; Sztein, Marcelo B; Levine, Myron M

2003-05-01

Measles remains a leading cause of child mortality in developing countries. Residual maternal measles antibodies and immunologic immaturity dampen immunogenicity of the current vaccine in young infants. Because cotton rat respiratory tract is susceptible to measles virus (MV) replication after intranasal (i.n.) challenge, this model can be used to assess the efficacy of MV vaccines. Pursuing a new measles vaccine strategy that might be effective in young infants, we used attenuated Salmonella enterica serovar Typhi CVD 908-htrA and Shigella flexneri 2a CVD 1208 vaccines to deliver mucosally to cotton rats eukaryotic expression plasmid pGA3-mH and Sindbis virus-based DNA replicon pMSIN-H encoding MV hemagglutinin (H). The initial i.n. dose-response with bacterial vectors alone identified a well-tolerated dosage (1 x 10(9) to 7 x 10(9) CFU) and a volume (20 micro l) that elicited strong antivector immune responses. Animals immunized i.n. on days 0, 28, and 76 with bacterial vectors carrying DNA plasmids encoding MV H or immunized parenterally with these naked DNA vaccine plasmids developed MV plaque reduction neutralizing antibodies and proliferative responses against MV antigens. In a subsequent experiment of identical design, cotton rats were challenged with wild-type MV 1 month after the third dose of vaccine or placebo. MV titers were significantly reduced in lung tissue of animals immunized with MV DNA vaccines delivered either via bacterial live vectors or parenterally. Since attenuated serovar Typhi and S. flexneri can deliver measles DNA vaccines mucosally in cotton rats, inducing measles immune responses (including neutralizing antibodies) and protection, boosting strategies can now be evaluated in animals primed with MV DNA vaccines.

Development of an Acid-Resistant Salmonella Typhi Ty21a Attenuated Vector For Improved Oral Vaccine Delivery.

PubMed

Dharmasena, Madushini N; Feuille, Catherine M; Starke, Carly Elizabeth C; Bhagwat, Arvind A; Stibitz, Scott; Kopecko, Dennis J

The licensed oral, live-attenuated bacterial vaccine for typhoid fever, Salmonella enterica serovar Typhi strain Ty21a, has also been utilized as a vaccine delivery platform for expression of diverse foreign antigens that stimulate protection against shigellosis, anthrax, plague, or human papilloma virus. However, Ty21a is acid-labile and, for effective oral immunization, stomach acidity has to be either neutralized with buffer or by-passed with Ty21a in an enteric-coated capsule (ECC). Several studies have shown that efficacy is reduced when Ty21a is administered in an ECC versus as a buffered liquid formulation, the former limiting exposure to GI tract lymphoid tissues. However, the ECC was selected as a more practical delivery format for both packaging/shipping and vaccine administration ease. We have sought to increase Ty21a acid-resistance to allow for removal from the ECC and immune enhancement. To improve Ty21a acid-resistance, glutamate-dependent acid resistance genes (GAD; responsible for Shigella spp. survival at very low pH) were cloned on a multi-copy plasmid (pGad) under a controllable arabinose-inducible promoter. pGad enhanced acid survival of Ty21a by 5 logs after 3 hours at pH 2.5, when cells were pre-grown in arabinose and under conditions that promote an acid-tolerance response (ATR). For genetically 100% stable expression, we inserted the gad genes into the Ty21a chromosome, using a method that allowed for subsequent removal of a selectable antibiotic resistance marker. Further, both bacterial growth curves and survival assays in cultured human monocytes/macrophages suggest that neither the genetic methods employed nor the resulting acid-resistance conferred by expression of the Gad proteins in Ty21a had any effect on the existing attenuation of this vaccine strain.

Polyamines are essential for virulence in Salmonella enterica serovar Gallinarum despite evolutionary decay of polyamine biosynthesis genes.

PubMed

Schroll, Casper; Christensen, Jens P; Christensen, Henrik; Pors, Susanne E; Thorndahl, Lotte; Jensen, Peter R; Olsen, John E; Jelsbak, Lotte

2014-05-14

Serovars of Salmonella enterica exhibit different host-specificities where some have broad host-ranges and others, like S. Gallinarum and S. Typhi, are host-specific for poultry and humans, respectively. With the recent availability of whole genome sequences it has been reported that host-specificity coincides with accumulation of pseudogenes, indicating adaptation of host-restricted serovars to their narrow niches. Polyamines are small cationic amines and in Salmonella they can be synthesized through two alternative pathways directly from l-ornithine to putrescine and from l-arginine via agmatine to putrescine. The first pathway is not active in S. Gallinarum and S. Typhi, and this prompted us to investigate the importance of polyamines for virulence in S. Gallinarum. Bioinformatic analysis of all sequenced genomes of Salmonella revealed that pseudogene formation of the speC gene was exclusive for S. Typhi and S. Gallinarum and happened through independent events. The remaining polyamine biosynthesis pathway was found to be essential for oral infection with S. Gallinarum since single and double mutants in speB and speE, encoding the pathways from agmatine to putrescine and from putrescine to spermidine, were attenuated. In contrast, speB was dispensable after intraperitoneal challenge, suggesting that putrescine was less important for the systemic phase of the disease. In support of this hypothesis, a ΔspeE;ΔpotCD mutant, unable to synthesize and import spermidine, but with retained ability to import and synthesize putrescine, was attenuated after intraperitoneal infection. We therefore conclude that polyamines are essential for virulence of S. Gallinarum. Furthermore, our results point to distinct roles for putrescine and spermidine during systemic infection. Copyright © 2014 Elsevier B.V. All rights reserved.

Salmonella myocarditis in a young adult patient presenting with acute pulmonary edema, rhabdomyolysis, and multi-organ failure.

PubMed

Al-aqeedi, Rafid Fayadh; Kamha, Ahmed; Al-aani, Fuad K; Al-ani, Ahmed A

2009-12-01

The mortality and morbidity of salmonella infections is seriously underestimated. Salmonella myocarditis is an unusual complication of salmonella sepsis in adults. Cases that do occur may be associated with high morbidity and mortality. We present a rare case of salmonella myocarditis with multi-organ failure in a previously healthy young adult man who was brought to the emergency room with fever, diarrhea, shortness of breath, and altered sensorium, discovered to have acute pulmonary edema and respiratory compromise for which he was assisted with mechanical ventilation for 8 days. Blood culture grew Salmonella typhi. Biochemically he exhibited myocardial, hepatic, and muscular enzymatic surge with renal failure, features of rhabdomyolysis, and disseminated intravascular coagulation. The patient showed a progressive improvement on treatment with ceftriaxone for 2 weeks in addition to decongestive therapy. He was discharged in good condition afterward.

Incidence of invasive salmonella disease in sub-Saharan Africa: a multicentre population-based surveillance study.

PubMed

Marks, Florian; von Kalckreuth, Vera; Aaby, Peter; Adu-Sarkodie, Yaw; El Tayeb, Muna Ahmed; Ali, Mohammad; Aseffa, Abraham; Baker, Stephen; Biggs, Holly M; Bjerregaard-Andersen, Morten; Breiman, Robert F; Campbell, James I; Cosmas, Leonard; Crump, John A; Espinoza, Ligia Maria Cruz; Deerin, Jessica Fung; Dekker, Denise Myriam; Fields, Barry S; Gasmelseed, Nagla; Hertz, Julian T; Van Minh Hoang, Nguyen; Im, Justin; Jaeger, Anna; Jeon, Hyon Jin; Kabore, Leon Parfait; Keddy, Karen H; Konings, Frank; Krumkamp, Ralf; Ley, Benedikt; Løfberg, Sandra Valborg; May, Jürgen; Meyer, Christian G; Mintz, Eric D; Montgomery, Joel M; Niang, Aissatou Ahmet; Nichols, Chelsea; Olack, Beatrice; Pak, Gi Deok; Panzner, Ursula; Park, Jin Kyung; Park, Se Eun; Rabezanahary, Henintsoa; Rakotozandrindrainy, Raphaël; Raminosoa, Tiana Mirana; Razafindrabe, Tsiriniaina Jean Luco; Sampo, Emmanuel; Schütt-Gerowitt, Heidi; Sow, Amy Gassama; Sarpong, Nimako; Seo, Hye Jin; Sooka, Arvinda; Soura, Abdramane Bassiahi; Tall, Adama; Teferi, Mekonnen; Thriemer, Kamala; Warren, Michelle R; Yeshitela, Biruk; Clemens, John D; Wierzba, Thomas F

2017-03-01

Available incidence data for invasive salmonella disease in sub-Saharan Africa are scarce. Standardised, multicountry data are required to better understand the nature and burden of disease in Africa. We aimed to measure the adjusted incidence estimates of typhoid fever and invasive non-typhoidal salmonella (iNTS) disease in sub-Saharan Africa, and the antimicrobial susceptibility profiles of the causative agents. We established a systematic, standardised surveillance of blood culture-based febrile illness in 13 African sentinel sites with previous reports of typhoid fever: Burkina Faso (two sites), Ethiopia, Ghana, Guinea-Bissau, Kenya, Madagascar (two sites), Senegal, South Africa, Sudan, and Tanzania (two sites). We used census data and health-care records to define study catchment areas and populations. Eligible participants were either inpatients or outpatients who resided within the catchment area and presented with tympanic (≥38·0°C) or axillary temperature (≥37·5°C). Inpatients with a reported history of fever for 72 h or longer were excluded. We also implemented a health-care utilisation survey in a sample of households randomly selected from each study area to investigate health-seeking behaviour in cases of self-reported fever lasting less than 3 days. Typhoid fever and iNTS disease incidences were corrected for health-care-seeking behaviour and recruitment. Between March 1, 2010, and Jan 31, 2014, 135 Salmonella enterica serotype Typhi (S Typhi) and 94 iNTS isolates were cultured from the blood of 13 431 febrile patients. Salmonella spp accounted for 33% or more of all bacterial pathogens at nine sites. The adjusted incidence rate (AIR) of S Typhi per 100 000 person-years of observation ranged from 0 (95% CI 0-0) in Sudan to 383 (274-535) at one site in Burkina Faso; the AIR of iNTS ranged from 0 in Sudan, Ethiopia, Madagascar (Isotry site), and South Africa to 237 (178-316) at the second site in Burkina Faso. The AIR of iNTS and typhoid

The relationship between infecting dose and severity of disease in reported outbreaks of Salmonella infections.

PubMed Central

Glynn, J. R.; Bradley, D. J.

1992-01-01

The relationship between size of the infecting dose and severity of the resulting disease has been investigated for salmonella infections by reanalysis of data within epidemics for 32 outbreaks, and comparing data between outbreaks for 68 typhoid epidemics and 49 food-poisoning outbreaks due to salmonellas. Attack rate, incubation period, amount of infected food consumed and type of vehicle are used as proxy measures of infecting dose, while case fatality rates for typhoid and case hospitalization rates for food poisoning salmonellas were used to assess severity. Limitations of the data are discussed. Both unweighted and logit analysis models are used. There is no evidence for a dose-severity relationship for Salmonella typhi, but evidence of a correlation between dose and severity is available from within-epidemic or between-epidemic analysis, or both, for Salmonella typhimurium, S. enteritidis, S. infantis, S. newport, and S. thompson. The presence of such a relationship affects the way in which control interventions should be assessed. PMID:1468522

Knowledge, attitude and practice of hygiene and sanitation in a Burundian refugee camp: implications for control of a Salmonella typhi outbreak.

PubMed

Nahimana, Marie-Rosette; Ngoc, Candide Tran; Olu, Olushayo; Nyamusore, Jose; Isiaka, Ayodeji; Ndahindwa, Vedaste; Dassanayake, Lakruwan; Rusanganwa, André

2017-01-01

A Salmonella typhi outbreak was reported in a Burundian refugee camp in Rwanda in October 2015. Transmission persisted despite increased hygiene promotion activities and hand-washing facilities instituted to prevent and control the outbreak. A knowledge, attitude and practice (KAP) study was carried out to assess the effectiveness of ongoing typhoid fever preventive interventions. A cross-sectional survey was conducted in Mahama Refugee Camp of Kirehe District, Rwanda from January to February 2016. Data were obtained through administration of a structured KAP questionnaire. Descriptive, bivariate and multivariate analysis was performed using STATA software. A total of 671 respondents comprising 264 (39.3%) males and 407 (60.7%) females were enrolled in the study. A comparison of hand washing practices before and after institution of prevention and control measures showed a 37% increase in the proportion of respondents who washed their hands before eating and after using the toilet (p < 0.001). About 52.8% of participants reported having heard about typhoid fever, however 25.9% had received health education. Only 34.6% and 38.6% of the respondents respectively knew how typhoid fever spreads and is prevented. Most respondents (98.2%) used pit latrines for disposal of feces. Long duration of stay in the camp, age over 35 years and being unemployed were statistically associated with poor hand washing practices. The findings of this study underline the need for bolstering up health education and hygiene promotion activities in Mahama and other refugee camp settings.

Salmonella enterica serovar-specific transcriptional reprogramming of infected cells.

PubMed

Hannemann, Sebastian; Galán, Jorge E

2017-07-01

Despite their high degree of genomic similarity, different Salmonella enterica serovars are often associated with very different clinical presentations. In humans, for example, the typhoidal S. enterica serovar Typhi causes typhoid fever, a life-threatening systemic disease. In contrast, the non-typhoidal S. enterica serovar Typhimurium causes self-limiting gastroenteritis. The molecular bases for these different clinical presentations are incompletely understood. The ability to re-program gene expression in host cells is an essential virulence factor for typhoidal and non-typhoidal S. enterica serovars. Here, we have compared the transcriptional profile of cultured epithelial cells infected with S. Typhimurium or S. Typhi. We found that both serovars stimulated distinct transcriptional responses in infected cells that are associated with the stimulation of specific signal transduction pathways. These specific responses were associated with the presence of a distinct repertoire of type III secretion effector proteins. These observations provide major insight into the molecular bases for potential differences in the pathogenic mechanisms of typhoidal and non-typhoidal S. enterica serovars.

Report of data on children with non-typhi Salmonella gastroenteritis in a three-year period.

PubMed

Küçük, Öznur; Biçer, Suat; Ugraş, Meltem; Çöl, Defne; Giray, Tuba; Çiler Erdag, Gülay; Gürol, Yeşim; Yilmaz, Gülden; Yalvaç, Zerrin; Vitrinel, Ayça; Kaspar, Çigdem

2016-09-01

The purpose of this study was to evaluate the clinical and laboratory data of children with acute gastroenteritis caused by non-typhoid Salmonella spp. infections. Clinical (demographic data, symptoms and findings) and laboratory data (stool microscopy, rapid antigen tests, culture, multiplex polymerase chain reaction and blood test results) of children with acute gastroenteritis caused by non-typhoid Salmonella spp. between January 2010 and October 2012 were evaluated. Differences between the groups for categorical variables were estimated with a chi-square or Fisher exact test; for continuous variables with two independent samples a t test was used. P values < 0.05 were considered statistically significant. Sixty-seven children, 39 (58.2%) males and 28 (41.8%) females aged between 1 - 16 years (mean ± SD: 4.64 ± 2.91), were diagnosed with acute bacterial gastroenteritis caused by non-typhoid Salmonella spp. The main serotypes are Salmonella enteritidis (85%) and Salmonella typhimurium (7.5%). The presenting symptoms were diarrhoea (95.5%), fever (61.1%), vomiting (34.3%), abdominal pain (32.8%), loss of appetite (7.4%) and malaise (7.4%). Fever and dehydration (moderate and/or severe) were detected in 11 (16.4%) patients. The mean leukocyte count was 10.930/μL [95% confidence interval (CI), SD: ± 5.710/μL], neutrophil count was 7.880/μL (95% CI, SD: ± 4.960/μL), CRP was 64.16 mg/L (95% CI, SD: ± 76.24 mg/L), and erythrocyte sedimentation rate was 34.72 mm/hour (95% CI, SD: ± 13.64 mm/h). Stool microscopy was positive for leukocytes in 18 patients (26.8%). The definitive diagnosis was made with positive stool culture (n = 65) and/or PCR test (n = 4). Viral antigen positivity was detected in 10 patients (14.9%), evaluated as viral co-infection and false positive results. Antibiotic therapy and hospitalization were required in 26 (38.8%) and 23 (34.3%) patients, respectively. Salmonella carriage was detected in one patient (1.5%). Bloody diarrhoea

Prevalence of antimicrobial resistance in Salmonella serotype Hadar isolated from humans, retail meat, and food animals at slaughter, United States, NARMS 1996-2008

USDA-ARS?s Scientific Manuscript database

Background Non-Typhi Salmonella (NTS) is a leading cause of bacterial gastroenteritis in the United States. Although most infections are self-limited, antibiotic treatment is essential for severe illness. Use of antimicrobial agents in food animals contributes to resistance in NTS. Multidrug resis...

Magnetophoretic separation ICP-MS immunoassay using Cs-doped multicore magnetic nanoparticles for the determination of salmonella typhimurium.

PubMed

Jeong, Arong; Lim, H B

2018-02-01

In this work, a magnetophoretic separation ICP-MS immunoassay using newly synthesized multicore magnetic nanoparticles (MMNPs) was developed for the determination of salmonella typhimurium (typhi). The uniqueness of this method was the use of MMNPs doped with Cs for both separation and detection, which enable us to achieve fast analysis, high sensitivity, and good reliability. For demonstration, heat-killed typhi in a phosphate buffer solution was determined by ICP-MS after the MMNP-typhi reaction product was separated from unreacted MMNPs in a micropipette tip filled with 25% polyethylene glycol through magnetophoretic separation. The calibration curve obtained by plotting 133 Cs intensity vs. the number of synthetic standard, showed a coefficient of determination (R 2 ) of 0.94 with a limit of detection (LOD) of 102 cells/mL without cell culturing. Excellent recoveries, between 98-100%, were obtained from four replicates and compared with a sandwich-type ICP-MS immunoassay for further confirmation. Copyright © 2017 Elsevier B.V. All rights reserved.

Evaluation of an Electricity-free, Culture-based Approach for Detecting Typhoidal Salmonella Bacteremia during Enteric Fever in a High Burden, Resource-limited Setting

PubMed Central

Andrews, Jason R.; Prajapati, Krishna G.; Eypper, Elizabeth; Shrestha, Poojan; Shakya, Mila; Pathak, Kamal R.; Joshi, Niva; Tiwari, Priyanka; Risal, Manisha; Koirala, Samir; Karkey, Abhilasha; Dongol, Sabina; Wen, Shawn; Smith, Amy B.; Maru, Duncan; Basnyat, Buddha; Baker, Stephen; Farrar, Jeremy; Ryan, Edward T.; Hohmann, Elizabeth; Arjyal, Amit

2013-01-01

Background In many rural areas at risk for enteric fever, there are few data on Salmonella enterica serotypes Typhi (S. Typhi) and Paratyphi (S. Paratyphi) incidence, due to limited laboratory capacity for microbiologic culture. Here, we describe an approach that permits recovery of the causative agents of enteric fever in such settings. This approach involves the use of an electricity-free incubator based upon use of phase-change materials. We compared this against conventional blood culture for detection of typhoidal Salmonella. Methodology/Principal Findings Three hundred and four patients with undifferentiated fever attending the outpatient and emergency departments of a public hospital in the Kathmandu Valley of Nepal were recruited. Conventional blood culture was compared against an electricity-free culture approach. Blood from 66 (21.7%) patients tested positive for a Gram-negative bacterium by at least one of the two methods. Sixty-five (21.4%) patients tested blood culture positive for S. Typhi (30; 9.9%) or S. Paratyphi A (35; 11.5%). From the 65 individuals with culture-confirmed enteric fever, 55 (84.6%) were identified by the conventional blood culture and 60 (92.3%) were identified by the experimental method. Median time-to-positivity was 2 days for both procedures. The experimental approach was falsely positive due to probable skin contaminants in 2 of 239 individuals (0.8%). The percentages of positive and negative agreement for diagnosis of enteric fever were 90.9% (95% CI: 80.0%–97.0%) and 96.0% (92.7%–98.1%), respectively. After initial incubation, Salmonella isolates could be readily recovered from blood culture bottles maintained at room temperature for six months. Conclusions/Significance A simple culture approach based upon a phase-change incubator can be used to isolate agents of enteric fever. This approach could be used as a surveillance tool to assess incidence and drug resistance of the etiologic agents of enteric fever in settings

Evaluation of an electricity-free, culture-based approach for detecting typhoidal Salmonella bacteremia during enteric fever in a high burden, resource-limited setting.

PubMed

Andrews, Jason R; Prajapati, Krishna G; Eypper, Elizabeth; Shrestha, Poojan; Shakya, Mila; Pathak, Kamal R; Joshi, Niva; Tiwari, Priyanka; Risal, Manisha; Koirala, Samir; Karkey, Abhilasha; Dongol, Sabina; Wen, Shawn; Smith, Amy B; Maru, Duncan; Basnyat, Buddha; Baker, Stephen; Farrar, Jeremy; Ryan, Edward T; Hohmann, Elizabeth; Arjyal, Amit

2013-01-01

In many rural areas at risk for enteric fever, there are few data on Salmonella enterica serotypes Typhi (S. Typhi) and Paratyphi (S. Paratyphi) incidence, due to limited laboratory capacity for microbiologic culture. Here, we describe an approach that permits recovery of the causative agents of enteric fever in such settings. This approach involves the use of an electricity-free incubator based upon use of phase-change materials. We compared this against conventional blood culture for detection of typhoidal Salmonella. Three hundred and four patients with undifferentiated fever attending the outpatient and emergency departments of a public hospital in the Kathmandu Valley of Nepal were recruited. Conventional blood culture was compared against an electricity-free culture approach. Blood from 66 (21.7%) patients tested positive for a Gram-negative bacterium by at least one of the two methods. Sixty-five (21.4%) patients tested blood culture positive for S. Typhi (30; 9.9%) or S. Paratyphi A (35; 11.5%). From the 65 individuals with culture-confirmed enteric fever, 55 (84.6%) were identified by the conventional blood culture and 60 (92.3%) were identified by the experimental method. Median time-to-positivity was 2 days for both procedures. The experimental approach was falsely positive due to probable skin contaminants in 2 of 239 individuals (0.8%). The percentages of positive and negative agreement for diagnosis of enteric fever were 90.9% (95% CI: 80.0%-97.0%) and 96.0% (92.7%-98.1%), respectively. After initial incubation, Salmonella isolates could be readily recovered from blood culture bottles maintained at room temperature for six months. A simple culture approach based upon a phase-change incubator can be used to isolate agents of enteric fever. This approach could be used as a surveillance tool to assess incidence and drug resistance of the etiologic agents of enteric fever in settings without reliable local access to electricity or local diagnostic

Differing Burden and Epidemiology of Non-Typhi Salmonella Bacteremia in Rural and Urban Kenya, 2006–2009

PubMed Central

Tabu, Collins; Breiman, Robert F.; Ochieng, Benjamin; Aura, Barrack; Cosmas, Leonard; Audi, Allan; Olack, Beatrice; Bigogo, Godfrey; Ongus, Juliette R.; Fields, Patricia; Mintz, Eric; Burton, Deron; Oundo, Joe; Feikin, Daniel R.

2012-01-01

Background The epidemiology of non-Typhi Salmonella (NTS) bacteremia in Africa will likely evolve as potential co-factors, such as HIV, malaria, and urbanization, also change. Methods As part of population-based surveillance among 55,000 persons in malaria-endemic, rural and malaria-nonendemic, urban Kenya from 2006–2009, blood cultures were obtained from patients presenting to referral clinics with fever ≥38.0°C or severe acute respiratory infection. Incidence rates were adjusted based on persons with compatible illnesses, but whose blood was not cultured. Results NTS accounted for 60/155 (39%) of blood culture isolates in the rural and 7/230 (3%) in the urban sites. The adjusted incidence in the rural site was 568/100,000 person-years, and the urban site was 51/100,000 person-years. In both sites, the incidence was highest in children <5 years old. The NTS-to-typhoid bacteremia ratio in the rural site was 4.6 and in the urban site was 0.05. S. Typhimurium represented >85% of blood NTS isolates in both sites, but only 21% (urban) and 64% (rural) of stool NTS isolates. Overall, 76% of S. Typhimurium blood isolates were multi-drug resistant, most of which had an identical profile in Pulse Field Gel Electrophoresis. In the rural site, the incidence of NTS bacteremia increased during the study period, concomitant with rising malaria prevalence (monthly correlation of malaria positive blood smears and NTS bacteremia cases, Spearman's correlation, p = 0.018 for children, p = 0.16 adults). In the rural site, 80% of adults with NTS bacteremia were HIV-infected. Six of 7 deaths within 90 days of NTS bacteremia had HIV/AIDS as the primary cause of death assigned on verbal autopsy. Conclusions NTS caused the majority of bacteremias in rural Kenya, but typhoid predominated in urban Kenya, which most likely reflects differences in malaria endemicity. Control measures for malaria, as well as HIV, will likely decrease the burden of NTS bacteremia in Africa. PMID

Oral administration of a Salmonella enterica-based vaccine expressing Bacillus anthracis protective antigen confers protection against aerosolized B. anthracis.

PubMed

Stokes, Margaret G M; Titball, Richard W; Neeson, Brendan N; Galen, James E; Walker, Nicola J; Stagg, Anthony J; Jenner, Dominic C; Thwaite, Joanne E; Nataro, James P; Baillie, Leslie W J; Atkins, Helen S

2007-04-01

Bacillus anthracis is the causative agent of anthrax, a disease that affects wildlife, livestock, and humans. Protection against anthrax is primarily afforded by immunity to the B. anthracis protective antigen (PA), particularly PA domains 4 and 1. To further the development of an orally delivered human vaccine for mass vaccination against anthrax, we produced Salmonella enterica serovar Typhimurium expressing full-length PA, PA domains 1 and 4, or PA domain 4 using codon-optimized PA DNA fused to the S. enterica serovar Typhi ClyA and under the control of the ompC promoter. Oral immunization of A/J mice with Salmonella expressing full-length PA protected five of six mice against a challenge with 10(5) CFU of aerosolized B. anthracis STI spores, whereas Salmonella expressing PA domains 1 and 4 provided only 25% protection (two of eight mice), and Salmonella expressing PA domain 4 or a Salmonella-only control afforded no measurable protection. However, a purified recombinant fusion protein of domains 1 and 4 provided 100% protection, and purified recombinant 4 provided protection in three of eight immunized mice. Thus, we demonstrate for the first time the efficacy of an oral S. enterica-based vaccine against aerosolized B. anthracis spores.

Knowledge, attitude and practice of hygiene and sanitation in a Burundian refugee camp: implications for control of a Salmonella typhi outbreak

PubMed Central

Nahimana, Marie-Rosette; Ngoc, Candide Tran; Olu, Olushayo; Nyamusore, Jose; Isiaka, Ayodeji; Ndahindwa, Vedaste; Dassanayake, Lakruwan; Rusanganwa, André

2017-01-01

Introduction A Salmonella typhi outbreak was reported in a Burundian refugee camp in Rwanda in October 2015. Transmission persisted despite increased hygiene promotion activities and hand-washing facilities instituted to prevent and control the outbreak. A knowledge, attitude and practice (KAP) study was carried out to assess the effectiveness of ongoing typhoid fever preventive interventions. Methods A cross-sectional survey was conducted in Mahama Refugee Camp of Kirehe District, Rwanda from January to February 2016. Data were obtained through administration of a structured KAP questionnaire. Descriptive, bivariate and multivariate analysis was performed using STATA software. Results A total of 671 respondents comprising 264 (39.3%) males and 407 (60.7%) females were enrolled in the study. A comparison of hand washing practices before and after institution of prevention and control measures showed a 37% increase in the proportion of respondents who washed their hands before eating and after using the toilet (p < 0.001). About 52.8% of participants reported having heard about typhoid fever, however 25.9% had received health education. Only 34.6% and 38.6% of the respondents respectively knew how typhoid fever spreads and is prevented. Most respondents (98.2%) used pit latrines for disposal of feces. Long duration of stay in the camp, age over 35 years and being unemployed were statistically associated with poor hand washing practices. Conclusion The findings of this study underline the need for bolstering up health education and hygiene promotion activities in Mahama and other refugee camp settings. PMID:29184606

Biggest Threats

MedlinePlus

... Resistant Salmonella Serotype Typhi Salmonella serotype Typhi causes typhoid fever, a potentially life-threatening disease. People with typhoid fever usually have a high fever, abdominal pain, and ...

Development of Recombinase Polymerase Amplification Assays for Detection of Orientia tsutsugamushi or Rickettsia typhi.

PubMed

Chao, Chien-Chung; Belinskaya, Tatyana; Zhang, Zhiwen; Ching, Wei-Mei

2015-01-01

Sensitive, specific and rapid diagnostic tests for the detection of Orientia tsutsugamushi (O. tsutsugamushi) and Rickettsia typhi (R. typhi), the causative agents of scrub typhus and murine typhus, respectively, are necessary to accurately and promptly diagnose patients and ensure that they receive proper treatment. Recombinase polymerase amplification (RPA) assays using a lateral flow test (RPA-nfo) and real-time fluorescent detection (RPA-exo) were developed targeting the 47-kDa gene of O. tsutsugamushi or 17 kDa gene of R. typhi. The RPA assay was capable of detecting O. tsutsugamushi or R. typhi at levels comparable to that of the quantitative PCR method. Both the RPA-nfo and RPA-exo methods performed similarly with regards to sensitivity when detecting the 17 kDa gene of R. typhi. On the contrary, RPA-exo performed better than RPA-nfo in detecting the 47 kDa gene of O. tsutsugamushi. The clinical performance of the O. tsutsugamushi RPA assay was evaluated using either human patient samples or infected mouse samples. Eight out of ten PCR confirmed positives were determined positive by RPA, and all PCR confirmed negative samples were negative by RPA. Similar results were obtained for R. typhi spiked patient sera. The assays were able to differentiate O. tsutsugamushi and R. typhi from other phylogenetically related bacteria as well as mouse and human DNA. Furthermore, the RPA-nfo reaction was completed in 20 minutes at 37°C followed by a 10 minute incubation at room temperature for development of an immunochromatographic strip. The RPA-exo reaction was completed in 20 minutes at 39°C. The implementation of a cross contamination proof cassette to detect the RPA-nfo fluorescent amplicons provided an alternative to regular lateral flow detection strips, which are more prone to cross contamination. The RPA assays provide a highly time-efficient, sensitive and specific alternative to other methods for diagnosing scrub typhus or murine typhus.

Development of Recombinase Polymerase Amplification Assays for Detection of Orientia tsutsugamushi or Rickettsia typhi

PubMed Central

Chao, Chien-Chung; Belinskaya, Tatyana; Zhang, Zhiwen; Ching, Wei-Mei

2015-01-01

Sensitive, specific and rapid diagnostic tests for the detection of Orientia tsutsugamushi (O. tsutsugamushi) and Rickettsia typhi (R. typhi), the causative agents of scrub typhus and murine typhus, respectively, are necessary to accurately and promptly diagnose patients and ensure that they receive proper treatment. Recombinase polymerase amplification (RPA) assays using a lateral flow test (RPA-nfo) and real-time fluorescent detection (RPA-exo) were developed targeting the 47-kDa gene of O. tsutsugamushi or 17 kDa gene of R. typhi. The RPA assay was capable of detecting O. tsutsugamushi or R. typhi at levels comparable to that of the quantitative PCR method. Both the RPA-nfo and RPA-exo methods performed similarly with regards to sensitivity when detecting the 17 kDa gene of R. typhi. On the contrary, RPA-exo performed better than RPA-nfo in detecting the 47 kDa gene of O. tsutsugamushi. The clinical performance of the O. tsutsugamushi RPA assay was evaluated using either human patient samples or infected mouse samples. Eight out of ten PCR confirmed positives were determined positive by RPA, and all PCR confirmed negative samples were negative by RPA. Similar results were obtained for R. typhi spiked patient sera. The assays were able to differentiate O. tsutsugamushi and R. typhi from other phylogenetically related bacteria as well as mouse and human DNA. Furthermore, the RPA-nfo reaction was completed in 20 minutes at 37oC followed by a 10 minute incubation at room temperature for development of an immunochromatographic strip. The RPA-exo reaction was completed in 20 minutes at 39oC. The implementation of a cross contamination proof cassette to detect the RPA-nfo fluorescent amplicons provided an alternative to regular lateral flow detection strips, which are more prone to cross contamination. The RPA assays provide a highly time-efficient, sensitive and specific alternative to other methods for diagnosing scrub typhus or murine typhus. PMID:26161793

[Experimental study of the inoculative transmission of Rickettsia typhi by gamasid mites (Gamasidae) Ornithonyssus bacoti].

PubMed

Grabarev, P A; Suroviatkin, A V; Tikhonova, Iu Iu; Mishchenko, O A; Potapenko, O V

2009-01-01

The authors' studies have established that the concentration of Rickettsia typhi may increase about 100-fold in the infected Ornithonyssus bacoti mites. At the time, when on feeding 20 to 200 adult mites on guinea-pigs and albino rats 4 to 36 days after inoculation, they did not transmit Rickettsia typhi on blood sucking.

Isolation, characterization, and application of bacteriophages for Salmonella spp. biocontrol in pigs.

PubMed

Albino, Luiz A A; Rostagno, Marcos H; Húngaro, Humberto M; Mendonça, Regina C S

2014-08-01

Foodborne illness due to Salmonella-contaminated pork products is an important public health problem, causing significant economic losses worldwide. The use of bacteriophages is a potential intervention tool that has attracted interest for the control of foodborne pathogens. The objective of this study was to detect the presence of Salmonella in commercial pig farms and to isolate specific autochthonous bacteriophages against Salmonella Typhimurium, to characterize them and to evaluate their lytic capacity against Salmonella Typhimurium in vivo and in vitro. Salmonella was isolated on 50% (4/8) of the farms, with serotype Typhimurium being the most prevalent, detected in 48.2% of samples (13/27). The isolated Salmonella Typhimurium bacteriophages belong to the Podoviridae family, were active against serotypes Abony, Enteritidis, Typhi, and Typhimurium, but not against serotypes Arizonae, Cholerasuis, Gallinarum, and Pullorum. In in vitro tests, bacteriophage at 10(7) PFU/mL and 10(9) PFU/mL significantly reduced (p<0.05) Salmonella Typhimurium counts in 1.6 and 2.5 log10 colony-forming units (CFU)/mL, respectively, after 24 h. Before the in vivo treatment with bacteriophages, Salmonella was identified in 93.3% (28/30) of the fecal samples from the pigs inoculated with 10(6) CFU/mL, and only in 56.6% (17/30) after the treatment consisting of oral administration of the pool of the bacteriophages after the fasting period, simulating a common preslaughter practice. These results indicate that the pool of bacteriophages administered was capable of reducing the colonization of Salmonella in pigs.

Antimicrobial sensitivity pattern of Salmonella: comparison of isolates from HIV-infected and HIV-uninfected patients.

PubMed

Wolday, D; Erge, W

1998-07-01

A retrospective analysis of all cases of Salmonella infections occurring between 1991 and 1995 was undertaken in order to evaluate the antimicrobial sensitivity pattern of the isolates from both human immunodeficiency virus (HIV) infected and uninfected Ethiopian patients. During the 5-year study period, we identified 147 cases of Salmonella infections. Only in 49 cases was the HIV serostatus known; 22 (44.9%) of the infections were in HIV seronegative patients while 27 (55.9%) were in HIV seropositive patients. The strains were isolated from blood (71.4%), urine (18.4%) and stool (8.2%). Salmonella infection was found to be more frequent (55.15% versus 44.9%) among HIV positive than HIV-negative patients. Moreover, Salmonella isolates recovered from HIV-seropositive patients were significantly resistant to many of the antibiotics tested when compared to the isolates from HIV-seronegative patients. The only chloramphenicol resistant Salmonella typhi occurred in a patient who was seropositive for HIV. According to these results, Ethiopian patients infected with HIV may be at risk of acquiring infections, especially non-typhoidal salmonellas, that are multi-drug resistant (MDR) strains than HIV-uninfected subjects. The emergence of MDR Salmonella infection among HIV-positive patients requires reassessment of chemotherapeutic approaches in this patient population, and warrants continued laboratory surveillance.

Expression, Extracellular Secretion, and Immunogenicity of the Plasmodium falciparum Sporozoite Surface Protein 2 in Salmonella Vaccine Strains

PubMed Central

Gómez-Duarte, Oscar G.; Pasetti, Marcela F.; Santiago, Araceli; Sztein, Marcelo B.; Hoffman, Stephen L.; Levine, Myron M.

2001-01-01

Deleting transmembrane α-helix motifs from Plasmodium falciparum sporozoite surface protein (SSP-2) allowed its secretion from Salmonella enterica serovar Typhimurium SL3261 and S. enterica serovar Typhi CVD 908-htrA by the Hly type I secretion system. In mice immunized intranasally, serovar Typhimurium constructs secreting SSP-2 stimulated greater gamma interferon splenocyte responses than did nonsecreting constructs (P = 0.04). PMID:11160021

Epidemiology, Clinical Presentation, Laboratory Diagnosis, Antimicrobial Resistance, and Antimicrobial Management of Invasive Salmonella Infections

PubMed Central

Sjölund-Karlsson, Maria; Gordon, Melita A.; Parry, Christopher M.

2015-01-01

SUMMARY Salmonella enterica infections are common causes of bloodstream infection in low-resource areas, where they may be difficult to distinguish from other febrile illnesses and may be associated with a high case fatality ratio. Microbiologic culture of blood or bone marrow remains the mainstay of laboratory diagnosis. Antimicrobial resistance has emerged in Salmonella enterica, initially to the traditional first-line drugs chloramphenicol, ampicillin, and trimethoprim-sulfamethoxazole. Decreased fluoroquinolone susceptibility and then fluoroquinolone resistance have developed in association with chromosomal mutations in the quinolone resistance-determining region of genes encoding DNA gyrase and topoisomerase IV and also by plasmid-mediated resistance mechanisms. Resistance to extended-spectrum cephalosporins has occurred more often in nontyphoidal than in typhoidal Salmonella strains. Azithromycin is effective for the management of uncomplicated typhoid fever and may serve as an alternative oral drug in areas where fluoroquinolone resistance is common. In 2013, CLSI lowered the ciprofloxacin susceptibility breakpoints to account for accumulating clinical, microbiologic, and pharmacokinetic-pharmacodynamic data suggesting that revision was needed for contemporary invasive Salmonella infections. Newly established CLSI guidelines for azithromycin and Salmonella enterica serovar Typhi were published in CLSI document M100 in 2015. PMID:26180063

Antimicrobial resistance and typing of Salmonella isolated from street vended foods and associated environment.

PubMed

Anukampa; Shagufta, Bi; Sivakumar, M; Kumar, Surender; Agarwal, Rajesh Kumar; Bhilegaonkar, Kiran Narayan; Kumar, Ashok; Dubal, Zunjar Baburao

2017-07-01

The present study was carried out to find out the occurrence and types of Salmonella present in street vended foods and associated environment, and their resistance pattern against various antibiotics. About 1075 street vended food and associated environment samples were processed for isolation and confirmation of different Salmonella spp. by targeting gene specific inv A gene and serotype specific Sdf I, Via B and Spy genes by PCR. Selected Salmonella isolates were screened for antibiotic resistance by using Baeur-Kirby disk diffusion test. Out of 1075 samples, only 31 (2.88%) isolates could be amplified the inv A gene of which 19 could be recovered from meat vendors; 8 from egg vendors while remaining 4 from milk vendors. Though, majority of Salmonella recovered from raw foods the ready-to-eat food like chicken gravy and rasmalai also showed its presence which pose a serious public health threat. Overall, 19, 6 and 1 isolates of S. Typhimurium, S. Enteritidis and S. Typhi could be detected by PCR while remaining 5 isolates could not be amplified suggesting other type of Salmonella. Selected Salmonella isolates were completely resistance to Oxacillin (100%) followed by Cefoxitin (30.43%) and Ampicillin (26.10%). Thus, it is observed that the street vended foods of animal origin and associated environment play an important role in transmission of food borne pathogens including Salmonella .

An experimental model of human body louse infection with Rickettsia typhi.

PubMed

Houhamdi, Linda; Fournier, Pierre-Edouard; Fang, Rong; Raoult, Didier

2003-06-01

Murine (endemic) typhus caused by Rickettsia typhi, one of the most widely distributed arthropod-borne diseases, is transmitted to humans mainly by the oriental rat flea. The human body louse, Pediculus humanus corporis, has been suspected to have a role in the transmission of R. typhi to humans. To evaluate the potential role of Pediculus humanus corporis as a vector of murine typhus, we used R. typhi in an experimental model of human body louse infection previously used with R. prowazekii. A rabbit was made bacteremic by inoculating it with 2 x 10(6) plaque-forming units of R. typhi; it remained bacteremic for at least 59 hours. Two hundred body lice infected by feeding on the bacteremic rabbit were compared to 200 uninfected control lice. Each louse population was fed once a day on the abdomen of a seronegative rabbit. On day 8 post-infection, as a result of disruption of the gut cells and leakage of the blood meal into the hemolymph, four infected lice became bright red and died within four hours. The life span of infected lice was 20 days less than that of the controls. Infected lice did not transmit R. typhi to their progeny (eggs and larvae) as demonstrated by PCR amplification and cell culture. With an immunofluorescence assay, R. typhi was detected in feces from day 7 post-infection, and the organism remained viable in feces for up to 80 days as demonstrated by cell culture. From the 21st day post-infection, the rabbit used to feed the R. typhi-infected lice developed an immunoglobulin response with a titer of 1:50 increasing to 1:200 at the 42nd day post-infection. It showed no clinical signs of infection. The rabbit that was used to feed uninfected lice remained seronegative. Although body lice are not clearly identified vectors of R. typhi, it seems that under certain circumstances they could transmit R. typhi.

Efficacy and immunogenicity of a Vi-tetanus toxoid conjugate vaccine in the prevention of typhoid fever using a controlled human infection model of Salmonella Typhi: a randomised controlled, phase 2b trial.

PubMed

Jin, Celina; Gibani, Malick M; Moore, Maria; Juel, Helene B; Jones, Elizabeth; Meiring, James; Harris, Victoria; Gardner, Jonathan; Nebykova, Anna; Kerridge, Simon A; Hill, Jennifer; Thomaides-Brears, Helena; Blohmke, Christoph J; Yu, Ly-Mee; Angus, Brian; Pollard, Andrew J

2017-12-02

Salmonella enterica serovar Typhi (S Typhi) is responsible for an estimated 20 million infections and 200 000 deaths each year in resource poor regions of the world. Capsular Vi-polysaccharide-protein conjugate vaccines (Vi-conjugate vaccines) are immunogenic and can be used from infancy but there are no efficacy data for the leading candidate vaccine being considered for widespread use. To address this knowledge gap, we assessed the efficacy of a Vi-tetanus toxoid conjugate vaccine using an established human infection model of S Typhi. In this single-centre, randomised controlled, phase 2b study, using an established outpatient-based human typhoid infection model, we recruited healthy adult volunteers aged between 18 and 60 years, with no previous history of typhoid vaccination, infection, or prolonged residency in a typhoid-endemic region. Participants were randomly assigned (1:1:1) to receive a single dose of Vi-conjugate (Vi-TT), Vi-polysaccharide (Vi-PS), or control meningococcal vaccine with a computer-generated randomisation schedule (block size 6). Investigators and participants were masked to treatment allocation, and an unmasked team of nurses administered the vaccines. Following oral ingestion of S Typhi, participants were assessed with daily blood culture over a 2-week period and diagnosed with typhoid infection when meeting pre-defined criteria. The primary endpoint was the proportion of participants diagnosed with typhoid infection (ie, attack rate), defined as persistent fever of 38°C or higher for 12 h or longer or S Typhi bacteraemia, following oral challenge administered 1 month after Vi-vaccination (Vi-TT or Vi-PS) compared with control vaccination. Analysis was per protocol. This trial is registered with ClinicalTrials.gov, number NCT02324751, and is ongoing. Between Aug 18, 2015, and Nov 4, 2016, 112 participants were enrolled and randomly assigned; 34 to the control group, 37 to the Vi-PS group, and 41 to the Vi-TT group. 103 participants

[Serotype and phage type distribution of human Salmonella strains isolated in Spain, 1997-2001].

PubMed

Echeita, María Aurora; Aladueña, Ana María; Díez, Rosa; Arroyo, Margarita; Cerdán, Francisca; Gutiérrez, Rafaela; de la Fuente, Manuela; González-Sanz, Rubén; Herrera-León, Silvia; Usera, Miguel Angel

2005-03-01

Salmonellosis is one of the most frequent causes of gastroenteritis in Spain. Serotyping is the gold standard epidemiological marker for subdividing Salmonella spp. strains. A small number of serotypes are very frequently isolated, reducing the discriminatory power of serotyping. Thus, to increase our knowledge of Salmonella spp. epidemiology, additional epidemiological markers, such as phage typing, should be used for this purpose. Salmonella spp. strains of human origin sent to the Laboratorio Nacional de Referencia de Salmonella y Shigella (LNRSSE, Spanish Reference Laboratory for Salmonella and Shigella) between 1997 and 2001 were serotyped using conventional agglutination methods, and Enteritidis, Typhimurium, Hadar, Virchow and Typhi serotypes were additionally phage typed according to internationally-developed schemes. A total of 30,856 Salmonella spp. strains, isolated in the majority of Spanish Autonomous Communities, were analyzed. Enteritidis (51%) and Typhimurium (24%) were the most frequently isolated serotypes. The following were the most frequent serotype/phage type combinations: Enteritidis/PT1 (18%), Enteritidis/PT4 (15%), Enteritidis/PT6a (5%), Typhimurium/DT104 (5%) and Enteritidis/PT6 (3%). The serotype Enteritidis/PT1 showed the greatest increase over the period studied, from 11.61% in 1997 to 24.74% in 2001. A hierarchical typing approach for Salmonella spp., using serotyping coupled with phage typing allowed a higher level of discrimination among Salmonella serotypes. Application of this approach in epidemiological studies could be highly useful for early characterization of related strains.

A Novel Chromogenic Ester Agar Medium for Detection of Salmonellae

PubMed Central

Cooke, Venitia M.; Miles, R. J.; Price, R. G.; Richardson, A. C.

1999-01-01

A novel agar medium, chromogenic Salmonella esterase (CSE) agar, for the differentiation of salmonellae is described. The agar contains peptones and nutrient extracts together with the following (grams per liter unless otherwise specified): 4-[2-(4-octanoyloxy-3,5-dimethoxyphenyl)-vinyl]-quinolinium-1-(propan-3-yl carboxylic acid) bromide (SLPA-octanoate; bromide form), 0.3223; lactose, 14.65; trisodium citrate dihydrate, 0.5; Tween 20, 3.0; ethyl 4-dimethylaminobenzoate, 0.035% (wt/vol), novobiocin, 70 mg liter−1. The key component of the medium is SLPA-octanoate, a newly synthesized ester formed from a C8 fatty acid and a phenolic chromophore. In CSE agar, the ester is hydrolyzed by Salmonella spp. to yield a brightly colored phenol which remains tightly bound within colonies. After 24 h of incubation at 37 or 42°C, colonies of typical Salmonella spp. were burgundy colored on a transparent yellow background, whereas non-Salmonella spp. were white, cream, yellow or transparent. CSE agar was evaluated by using a panel of strains including a high proportion of Salmonella and non-Salmonella strains giving atypical reactions on other differential agars. The sensitivity (93.1%) of CSE agar for non-typhi salmonellae compared favorably with those of Rambach (82.8%), xylose-lysine-deoxycholate (XLD; 91.4%), Hektoen-enteric (89.7%), and SM ID (91.4%) agars. The specificity (93.9%) was also comparable to those of other Salmonella media (SM ID agar, 95.9%; Rambach agar, 91.8%; XLD agar, 91.8%; Hektoen-enteric agar, 87.8%). Strains of Citrobacter freundii and Proteus spp. giving false-positive reactions with other media gave a negative color reaction on CSE agar. CSE agar enabled the detection of >30 Salmonella serotypes, including agona, anatum, enteritidis, hadar, heidelberg, infantis, montevideo, thompson, typhimurium, and virchow, which accounted for 91.8% of the salmonella isolates recorded by the Public Health Laboratory Service (Colindale, London, England) for 1997

Characterization of Salmonella enterica isolates causing bacteremia in Lima, Peru, using multiple typing methods

PubMed Central

Betancor, Laura; García, Coralith; Astocondor, Lizeth; Hinostroza, Noemí; Bisio, Julieta; Rivera, Javier; Perezgasga, Lucía; Pérez Escanda, Victoria; Yim, Lucía; Jacobs, Jan; García-del Portillo, Francisco; Chabalgoity, José A.; Puente, José L.

2017-01-01

In this study, different molecular typing tools were applied to characterize 95 Salmonella enterica blood isolates collected between 2008 and 2013 from patients at nine public hospitals in Lima, Peru. Combined results of multiplex PCR serotyping, two- and seven-loci multilocus sequence typing (MLST) schemes, serotyping, IS200 amplification and RAPD fingerprints, showed that these infections were caused by eight different serovars: Enteritidis, Typhimurium, Typhi, Choleraesuis, Dublin, Paratyphi A, Paratyphi B and Infantis. Among these, Enteritidis, Typhimurium and Typhi were the most prevalent, representing 45, 36 and 11% of the isolates, respectively. Most isolates (74%) were not resistant to ten primarily used antimicrobial drugs; however, 37% of the strains showed intermediate susceptibility to ciprofloxacin (ISC). Antimicrobial resistance integrons were carried by one Dublin (dfra1 and aadA1) and two Infantis (aadA1) isolates. The two Infantis isolates were multidrug resistant and harbored a large megaplasmid. Amplification of spvC and spvRA regions showed that all Enteritidis (n = 42), Typhimurium (n = 34), Choleraesuis (n = 3) and Dublin (n = 1) isolates carried the Salmonella virulence plasmid (pSV). We conclude that the classic serotyping method can be substituted by the multiplex PCR and, when necessary, sequencing of only one or two loci of the MLST scheme is a valuable tool to confirm the results. The effectiveness and feasibility of different typing tools is discussed. PMID:29267322

Antimicrobial resistance and management of invasive Salmonella disease.

PubMed

Kariuki, Samuel; Gordon, Melita A; Feasey, Nicholas; Parry, Christopher M

2015-06-19

Invasive Salmonella infections (typhoidal and non-typhoidal) cause a huge burden of illness estimated at nearly 3.4 million cases and over 600,000 deaths annually especially in resource-limited settings. Invasive non-typhoidal Salmonella (iNTS) infections are particularly important in immunosuppressed populations especially in sub-Saharan Africa, causing a mortality of 20-30% in vulnerable children below 5 years of age. In these settings, where routine surveillance for antimicrobial resistance is rare or non-existent, reports of 50-75% multidrug resistance (MDR) in NTS are common, including strains of NTS also resistant to flouroquinolones and 3rd generation cephalosporins. Typhoid (enteric) fever caused by Salmonella Typhi and Salmonella Paratyphi A remains a major public health problem in many parts of Asia and Africa. Currently over a third of isolates in many endemic areas are MDR, and diminished susceptibility or resistance to fluoroquinolones, the drugs of choice for MDR cases over the last decade is an increasing problem. The situation is particularly worrying in resource-limited settings where the few remaining effective antimicrobials are either unavailable or altogether too expensive to be afforded by either the general public or by public health services. Although the prudent use of effective antimicrobials, improved hygiene and sanitation and the discovery of new antimicrobial agents may offer hope for the management of invasive salmonella infections, it is essential to consider other interventions including the wider use of WHO recommended typhoid vaccines and the acceleration of trials for novel iNTS vaccines. The main objective of this review is to describe existing data on the prevalence and epidemiology of antimicrobial resistant invasive Salmonella infections and how this affects the management of these infections, especially in endemic developing countries. Copyright © 2015. Published by Elsevier Ltd.

Antimicrobial resistance and management of invasive Salmonella disease

PubMed Central

Kariuki, Samuel; Gordon, Melita A.; Feasey, Nicholas; Parry, Christopher M

2015-01-01

Invasive Salmonella infections (typhoidal and non-typhoidal) cause a huge burden of illness estimated at nearly 3.4 million cases and over 600,000 deaths annually especially in resource-limited settings. Invasive non-typhoidal Salmonella (iNTS) infections are particularly important in immunosuppressed populations especially in sub-Saharan Africa, causing a mortality of 20–30% in vulnerable children below 5 years of age. In these settings, where routine surveillance for antimicrobial resistance is rare or non-existent, reports of 50–75% multidrug resistance (MDR) in NTS are common, including strains of NTS also resistant to flouroquinolones and 3rd generation cephalosporins. Typhoid (enteric) fever caused by Salmonella Typhi and Salmonella Paratyphi A remains a major public health problem in many parts of Asia and Africa. Currently over a third of isolates in many endemic areas are MDR, and diminished susceptibility or resistance to fluoroquinolones, the drugs of choice for MDR cases over the last decade is an increasing problem. The situation is particularly worrying in resource-limited settings where the few remaining effective antimicrobials are either unavailable or altogether too expensive to be afforded by either the general public or by public health services. Although the prudent use of effective antimicrobials, improved hygiene and sanitation and the discovery of new antimicrobial agents may offer hope for the management of invasive salmonella infections, it is essential to consider other interventions including the wider use of WHO recommended typhoid vaccines and the acceleration of trials for novel iNTS vaccines. The main objective of this review is to describe existing data on the prevalence and epidemiology of antimicrobial resistant invasive Salmonella infections and how this affects the management of these infections, especially in endemic developing countries. PMID:25912288

Real-Time PCR Method for Detection of Salmonella spp. in Environmental Samples.

PubMed

Kasturi, Kuppuswamy N; Drgon, Tomas

2017-07-15

The methods currently used for detecting Salmonella in environmental samples require 2 days to produce results and have limited sensitivity. Here, we describe the development and validation of a real-time PCR Salmonella screening method that produces results in 18 to 24 h. Primers and probes specific to the gene invA , group D, and Salmonella enterica serovar Enteritidis organisms were designed and evaluated for inclusivity and exclusivity using a panel of 329 Salmonella isolates representing 126 serovars and 22 non- Salmonella organisms. The invA - and group D-specific sets identified all the isolates accurately. The PCR method had 100% inclusivity and detected 1 to 2 copies of Salmonella DNA per reaction. Primers specific for Salmonella -differentiating fragment 1 (Sdf-1) in conjunction with the group D set had 100% inclusivity for 32 S Enteritidis isolates and 100% exclusivity for the 297 non-Enteritidis Salmonella isolates. Single-laboratory validation performed on 1,741 environmental samples demonstrated that the PCR method detected 55% more positives than the V itek i mmuno d iagnostic a ssay s ystem (VIDAS) method. The PCR results correlated well with the culture results, and the method did not report any false-negative results. The receiver operating characteristic (ROC) analysis documented excellent agreement between the results from the culture and PCR methods (area under the curve, 0.90; 95% confidence interval of 0.76 to 1.0) confirming the validity of the PCR method. IMPORTANCE This validated PCR method detects 55% more positives for Salmonella in half the time required for the reference method, VIDAS. The validated PCR method will help to strengthen public health efforts through rapid screening of Salmonella spp. in environmental samples.

Real-Time PCR Method for Detection of Salmonella spp. in Environmental Samples

PubMed Central

Drgon, Tomas

2017-01-01

ABSTRACT The methods currently used for detecting Salmonella in environmental samples require 2 days to produce results and have limited sensitivity. Here, we describe the development and validation of a real-time PCR Salmonella screening method that produces results in 18 to 24 h. Primers and probes specific to the gene invA, group D, and Salmonella enterica serovar Enteritidis organisms were designed and evaluated for inclusivity and exclusivity using a panel of 329 Salmonella isolates representing 126 serovars and 22 non-Salmonella organisms. The invA- and group D-specific sets identified all the isolates accurately. The PCR method had 100% inclusivity and detected 1 to 2 copies of Salmonella DNA per reaction. Primers specific for Salmonella-differentiating fragment 1 (Sdf-1) in conjunction with the group D set had 100% inclusivity for 32 S. Enteritidis isolates and 100% exclusivity for the 297 non-Enteritidis Salmonella isolates. Single-laboratory validation performed on 1,741 environmental samples demonstrated that the PCR method detected 55% more positives than the Vitek immunodiagnostic assay system (VIDAS) method. The PCR results correlated well with the culture results, and the method did not report any false-negative results. The receiver operating characteristic (ROC) analysis documented excellent agreement between the results from the culture and PCR methods (area under the curve, 0.90; 95% confidence interval of 0.76 to 1.0) confirming the validity of the PCR method. IMPORTANCE This validated PCR method detects 55% more positives for Salmonella in half the time required for the reference method, VIDAS. The validated PCR method will help to strengthen public health efforts through rapid screening of Salmonella spp. in environmental samples. PMID:28500041

Salmonella infections associated with international travel: a Foodborne Diseases Active Surveillance Network (FoodNet) study.

PubMed

Johnson, Laura R; Gould, L Hannah; Dunn, John R; Berkelman, Ruth; Mahon, Barbara E

2011-09-01

Salmonella species cause an estimated 1.2 million infections per year in the United States, making it one of the most commonly reported enteric pathogens. In addition, Salmonella is an important cause of travel-associated diarrhea and enteric fever, a systemic illness commonly associated with Salmonella serotypes Typhi and Paratyphi A. We reviewed cases of Salmonella infection reported to the Centers for Disease Control and Prevention's (CDC) Foodborne Diseases Active Surveillance Network (FoodNet), a sentinel surveillance network, from 2004 to 2008. We compared travelers with Salmonella infection to nontravelers with Salmonella infection with respect to demographics, clinical characteristics, and serotypes. Among 23,712 case-patients with known travel status, 11% had traveled internationally in the 7 days before illness. Travelers with Salmonella infection tended to be older (median age, 30 years) than nontravelers (median age, 24 years; p<0.0001), but were similar with respect to gender. The most common destinations reported were Mexico (38% of travel-associated infections), India (9%), Jamaica (7%), the Dominican Republic (4%), China (3%), and the Bahamas (2%). The proportions of travelers with Salmonella infection hospitalized and with invasive disease were inversely related to the income level of the destination (p<0.0001). The most commonly reported serotypes, regardless of travel status, were Enteritidis (19% of cases), Typhimurium (14%), Newport (9%), and Javiana (5%). Among infections caused by these four serotypes, 22%, 6%, 5%, and 4%, respectively, were associated with travel. A high index of clinical suspicion for Salmonella infection is appropriate when evaluating recent travelers, especially those who visited Africa, Asia, or Latin America.

Ultra-Fast and Sensitive Detection of Non-Typhoidal Salmonella Using Microwave-Accelerated Metal-Enhanced Fluorescence (“MAMEF”)

PubMed Central

Galen, James E.; Geddes, Chris D.; Levine, Myron M.

2011-01-01

Certain serovars of Salmonella enterica subsp. enterica cause invasive disease (e.g., enteric fever, bacteremia, septicemia, meningitis, etc.) in humans and constitute a global public health problem. A rapid, sensitive diagnostic test is needed to allow prompt initiation of therapy in individual patients and for measuring disease burden at the population level. An innovative and promising new rapid diagnostic technique is microwave-accelerated metal-enhanced fluorescence (MAMEF). We have adapted this assay platform to detect the chromosomal oriC locus common to all Salmonella enterica subsp. enterica serovars. We have shown efficient lysis of biologically relevant concentrations of Salmonella spp. suspended in bacteriological media using microwave-induced lysis. Following lysis and DNA release, as little as 1 CFU of Salmonella in 1 ml of medium can be detected in <30 seconds. Furthermore the assay is sensitive and specific: it can detect oriC from Salmonella serovars Typhi, Paratyphi A, Paratyphi B, Paratyphi C, Typhimurium, Enteritidis and Choleraesuis but does not detect Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Streptococcus pneumoniae, Haemophilus influenzae or Acinetobacter baumanii. We have also performed preliminary experiments using a synthetic Salmonella oriC oligonucleotide suspended in whole human blood and observed rapid detection when the sample was diluted 1∶1 with PBS. These pre-clinical data encourage progress to the next step to detect Salmonella in blood (and other ordinarily sterile, clinically relevant body fluids). PMID:21494634

Repression of Salmonella enterica phoP Expression by Small Molecules from Physiological Bile

PubMed Central

Antunes, L. Caetano M.; Wang, Melody; Andersen, Sarah K.; Ferreira, Rosana B. R.; Kappelhoff, Reinhild; Han, Jun; Borchers, Christoph H.

2012-01-01

Infection with Salmonella enterica serovar Typhi in humans causes the life-threatening disease typhoid fever. In the laboratory, typhoid fever can be modeled through the inoculation of susceptible mice with Salmonella enterica serovar Typhimurium. Using this murine model, we previously characterized the interactions between Salmonella Typhimurium and host cells in the gallbladder and showed that this pathogen can successfully invade gallbladder epithelial cells and proliferate. Additionally, we showed that Salmonella Typhimurium can use bile phospholipids to grow at high rates. These abilities are likely important for quick colonization of the gallbladder during typhoid fever and further pathogen dissemination through fecal shedding. To further characterize the interactions between Salmonella and the gallbladder environment, we compared the transcriptomes of Salmonella cultures grown in LB broth or physiological murine bile. Our data showed that many genes involved in bacterial central metabolism are affected by bile, with the citric acid cycle being repressed and alternative respiratory systems being activated. Additionally, our study revealed a new aspect of Salmonella interactions with bile through the identification of the global regulator phoP as a bile-responsive gene. Repression of phoP expression could also be achieved using physiological, but not commercial, bovine bile. The biological activity does not involve PhoPQ sensing of a bile component and is not caused by bile acids, the most abundant organic components of bile. Bioactivity-guided purification allowed the identification of a subset of small molecules from bile that can elicit full activity; however, a single compound with phoP inhibitory activity could not be isolated, suggesting that multiple molecules may act in synergy to achieve this effect. Due to the critical role of phoP in Salmonella virulence, further studies in this area will likely reveal aspects of the interaction between Salmonella

Salmonella Extracellular Matrix Components Influence Biofilm Formation and Gallbladder Colonization.

PubMed

Adcox, Haley E; Vasicek, Erin M; Dwivedi, Varun; Hoang, Ky V; Turner, Joanne; Gunn, John S

2016-11-01

Salmonella enterica serovar Typhi, the causative agent of typhoid fever in humans, forms biofilms encapsulated by an extracellular matrix (ECM). Biofilms facilitate colonization and persistent infection in gallbladders of humans and mouse models of chronic carriage. Individual roles of matrix components have not been completely elucidated in vitro or in vivo To examine individual functions, strains of Salmonella enterica serovar Typhimurium, the murine model of S Typhi, in which various ECM genes were deleted or added, were created to examine biofilm formation, colonization, and persistence in the gallbladder. Studies show that curli contributes most significantly to biofilm formation. Expression of Vi antigen decreased biofilm formation in vitro and virulence and bacterial survival in vivo without altering the examined gallbladder pro- or anti-inflammatory cytokines. Oppositely, loss of all ECM components (ΔwcaM ΔcsgA ΔyihO ΔbcsE) increased virulence and bacterial survival in vivo and reduced gallbladder interleukin-10 (IL-10) levels. Colanic acid and curli mutants had the largest defects in biofilm-forming ability and contributed most significantly to the virulence increase of the ΔwcaM ΔcsgA ΔyihO ΔbcsE mutant strain. While the ΔwcaM ΔcsgA ΔyihO ΔbcsE mutant was not altered in resistance to complement or growth in macrophages, it attached and invaded macrophages better than the wild-type (WT) strain. These data suggest that ECM components have various levels of importance in biofilm formation and gallbladder colonization and that the ECM diminishes disseminated disease in our model, perhaps by reducing cell attachment/invasion and dampening inflammation by maintaining/inducing IL-10 production. Understanding how ECM components aid acute disease and persistence could lead to improvements in therapeutic treatment of typhoid fever patients. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Functional Activity of Antibodies Directed towards Flagellin Proteins of Non-Typhoidal Salmonella

PubMed Central

Boyd, Mary A.; Wang, Jin Y.; Tulapurkar, Mohan E.; Pasetti, Marcela F.; Levine, Myron M.; Simon, Raphael

2016-01-01

Non-typhoidal Salmonella (NTS) serovars Typhimurium and Enteritidis are major causes of invasive bacterial infections in children under 5 years old in sub-Saharan Africa, with case fatality rates of ~20%. There are no licensed NTS vaccines for humans. Vaccines that induce antibodies against a Salmonella Typhi surface antigen, Vi polysaccharide, significantly protect humans against typhoid fever, establishing that immune responses to Salmonella surface antigens can be protective. Flagella proteins, abundant surface antigens in Salmonella serovars that cause human disease, are also powerful immunogens, but the functional capacity of elicited anti-flagellar antibodies and their role in facilitating bacterial clearance has been unclear. We examined the ability of anti-flagellar antibodies to mediate microbial killing by immune system components in-vitro and assessed their role in protecting mice against invasive Salmonella infection. Polyclonal (hyperimmune sera) and monoclonal antibodies raised against phase 1 flagellin proteins of S. Enteritidis and S. Typhimurium facilitated bacterial uptake and killing of the homologous serovar pathogen by phagocytes. Polyclonal anti-flagellar antibodies accompanied by complement also achieved direct bacterial killing. Serum bactericidal activity was restricted to Salmonella serovars expressing the same flagellin used as immunogen. Notably, individual anti-flagellin monoclonal antibodies with complement were not bactericidal, but this biological activity was restored when different monoclonal anti-flagellin antibodies were combined. Passive transfer immunization with a monoclonal IgG antibody specific for phase 1 flagellin from S. Typhimurium protected mice against lethal challenge with a representative African invasive S. Typhimurium strain. These findings have relevance for the use of flagellin proteins in NTS vaccines, and confirm the role of anti-flagellin antibodies as mediators of protective immunity. PMID:26998925

[Enzyme-linked immunosorbent assay (ELISA) for detection of antibodies to Salmonella Typhi lipopolysaccharide O and capsular polysaccharide Vi antigens in persons from outbreak of typhoid fever].

PubMed

Rastawicki, Waldemar; Kałużewski, Stanisław

2015-01-01

The laboratory diagnosis of typhoid fever is dependent upon either isolation of S. Typhi from a clinical sample or the detection of raised titers of serum antibodies in the Widal test or the passive hemagglutination assay (PHA). In this study we evaluated the usefulness of ELISA for detection of antibodies to S. Typhi lipopolysaccharide O and capsular polysaccharide Vi antigens in the sera of persons from outbreak of typhoid fever. Fifteen serum samples from patients with laboratory confirmed typhoid fever and 140 sera from persons suspected for contact with typhoid fever patients from outbreak in 1974/75 in Poland were tested by ELISA. Additionally, as the control group, we tested 115 sera from blood donors for the presence of S. Typhi anti-LPS and anti-Vi antibodies. Anti-LPS and anti-Vi antibodies were detected in 80% and 53.3% of sera obtained from patients with laboratory confirmed typhoid fever, respectively. The high percentages of positive results in ELISA were also noted in the group of persons suspected for contact with typhoid fever patients (51.4% and 45%) but not in the group of blood donors (7.8% and 6.1%, respectively). The ELISA could be a useful tool for the serological diagnosis of typhoid fever in patients who have clinical symptoms but are culture negative, especially during massive outbreaks of typhoid fever.

Antimicrobial activity of the bioactive components of essential oils from Pakistani spices against Salmonella and other multi-drug resistant bacteria

PubMed Central

2013-01-01

Background The main objective of this study was the phytochemical characterization of four indigenous essential oils obtained from spices and their antibacterial activities against the multidrug resistant clinical and soil isolates prevalent in Pakistan, and ATCC reference strains. Methods Chemical composition of essential oils from four Pakistani spices cumin (Cuminum cyminum), cinnamon (Cinnamomum verum), cardamom (Amomum subulatum) and clove (Syzygium aromaticum) were analyzed on GC/MS. Their antibacterial activities were investigated by minimum inhibitory concentration (MIC) and Thin-Layer Chromatography-Bioautographic (TLC-Bioautographic) assays against pathogenic strains Salmonella typhi (D1 Vi-positive), Salmonella typhi (G7 Vi-negative), Salmonella paratyphi A, Escherichia coli (SS1), Staphylococcus aureus, Pseudomonas fluorescens and Bacillus licheniformis (ATCC 14580). The data were statistically analyzed by using Analysis of Variance (ANOVA) and Least Significant Difference (LSD) method to find out significant relationship of essential oils biological activities at p <0.05. Results Among all the tested essential oils, oil from the bark of C. verum showed best antibacterial activities against all selected bacterial strains in the MIC assay, especially with 2.9 mg/ml concentration against S. typhi G7 Vi-negative and P. fluorescens strains. TLC-bioautography confirmed the presence of biologically active anti-microbial components in all tested essential oils. P. fluorescens was found susceptible to C. verum essential oil while E. coli SS1 and S. aureus were resistant to C. verum and A. subulatum essential oils, respectively, as determined in bioautography assay. The GC/MS analysis revealed that essential oils of C. cyminum, C. verum, A. subulatum, and S. aromaticum contain 17.2% cuminaldehyde, 4.3% t-cinnamaldehyde, 5.2% eucalyptol and 0.73% eugenol, respectively. Conclusions Most of the essential oils included in this study possessed good antibacterial

Applications of immunomagnetic capture and time-resolved fluorescence detection for Salmonella enteriditis in liquid eggs

NASA Astrophysics Data System (ADS)

Tu, Shu-I.; Gehring, Andrew; Paoli, George

2008-04-01

An immuno sandwich method was evaluated for the detection of Salmonella in liquid eggs. Liquid eggs spiked with different out-break strains of Salmonella were mixed with proper enrichment media and incubated at 37 C for 4 to 20 h. After enrichment, immunomagnetic beads (IMB) coated with anti Salmonella antibodies were used to capture the bacteria. Samarium (Sm) labeled anti Salmonella antibodies were then used to form sandwiched complexes with IMB captured bacteria. Sandwiched Salmonella were then treated with Sm-chelator to allow the measurement of the released Sm by time-resolved fluorescence (TRF). The processes ranging from IMB capture to Sm chelation were performed using an automated KingFisher apparatus. With this approach, the presence of ~ 1 CFU of outbreak strains of Salmonella Enteritidis per egg (~50 g of liquid eggs) could be detected after enrichment for 20 h at 37 C. For higher levels of Salmonella Enteritidis contamination, e.g., 10 CFU per 50 g of liquid eggs, the enrichment time could be reduced to 5 h at 37 C. The results demonstrated that a combination of IMB capture and TRF measurement could be a rapid and sensitive method for Salmonella Enteritidis detection in liquid eggs.

Use of enrichment real-time PCR to enumerate salmonella on chicken parts.

PubMed

Oscar, T P

2014-07-01

Salmonella bacteria that survive cooking or that cross-contaminate other food during meal preparation and serving represent primary routes of consumer exposure to this pathogen from chicken. In the present study, enrichment real-time PCR (qPCR) was used to enumerate Salmonella bacteria that contaminate raw chicken parts at retail or that cross-contaminate cooked chicken during simulated meal preparation and serving. Whole raw chickens obtained at retail were partitioned into wings, breasts, thighs, and drumsticks using a sterilized knife and cutting board, which were then used to partition a cooked chicken breast to assess cross-contamination. After enrichment in buffered peptone water (400 ml, 8 h, 40°C, 80 rpm), subsamples were used for qPCR and cultural isolation of Salmonella. In some experiments, chicken parts were spiked with 0 to 3.6 log of Salmonella Typhimurium var. 5- to generate a standard curve for enumeration by qPCR. Of 10 raw chickens examined, 7 (70%) had one or more parts contaminated with Salmonella. Of 80 raw parts examined, 15 (19%) were contaminated with Salmonella. Of 20 cooked chicken parts examined, 2 (10%) were cross-contaminated with Salmonella. Predominant serotypes identified were Typhimurium (71%) and its variants (var. 5-, monophasic, and nonmotile) and Kentucky (18%). The number of Salmonella bacteria on contaminated parts ranged from one to two per part. Results of this study indicated that retail chicken parts examined were contaminated with low levels of Salmonella, which resulted in low levels of cross-contamination during simulated meal preparation and serving. Thus, if consumers properly handle and prepare the chicken, it should pose no or very low risk of consumer exposure to Salmonella.

Crl binds to domain 2 of σ(S) and confers a competitive advantage on a natural rpoS mutant of Salmonella enterica serovar Typhi.

PubMed

Monteil, Véronique; Kolb, Annie; Mayer, Claudine; Hoos, Sylviane; England, Patrick; Norel, Françoise

2010-12-01

The RpoS sigma factor (σ(S)) is the master regulator of the bacterial response to a variety of stresses. Mutants in rpoS arise in bacterial populations in the absence of stress, probably as a consequence of a subtle balance between self-preservation and nutritional competence. We characterized here one natural rpoS mutant of Salmonella enterica serovar Typhi (Ty19). We show that the rpoS allele of Ty19 (rpoS(Ty19)) led to the synthesis of a σ(S)(Ty19) protein carrying a single glycine-to-valine substitution at position 282 in σ(S) domain 4, which was much more dependent than the wild-type σ(S) protein on activation by Crl, a chaperone-like protein that increases the affinity of σ(S) for the RNA polymerase core enzyme (E). We used the bacterial adenylate cyclase two-hybrid system to demonstrate that Crl bound to residues 72 to 167 of σ(S) domain 2 and that G282V substitution did not directly affect Crl binding. However, this substitution drastically reduced the ability of σ(S)(Ty19) to bind E in a surface plasmon resonance assay, a defect partially rescued by Crl. The modeled structure of the Eσ(S) holoenzyme suggested that substitution G282V could directly disrupt a favorable interaction between σ(S) and E. The rpoS(Ty19) allele conferred a competitive fitness when the bacterial population was wild type for crl but was outcompeted in Δcrl populations. Thus, these results indicate that the competitive advantage of the rpoS(Ty19) mutant is dependent on Crl and suggest that crl plays a role in the appearance of rpoS mutants in bacterial populations.

Evolution of Salmonella enterica Virulence via Point Mutations in the Fimbrial Adhesin

PubMed Central

Kisiela, Dagmara I.; Chattopadhyay, Sujay; Libby, Stephen J.; Karlinsey, Joyce E.; Fang, Ferric C.; Tchesnokova, Veronika; Kramer, Jeremy J.; Beskhlebnaya, Viktoriya; Samadpour, Mansour; Grzymajlo, Krzysztof; Ugorski, Maciej; Lankau, Emily W.; Mackie, Roderick I.; Clegg, Steven; Sokurenko, Evgeni V.

2012-01-01

Whereas the majority of pathogenic Salmonella serovars are capable of infecting many different animal species, typically producing a self-limited gastroenteritis, serovars with narrow host-specificity exhibit increased virulence and their infections frequently result in fatal systemic diseases. In our study, a genetic and functional analysis of the mannose-specific type 1 fimbrial adhesin FimH from a variety of serovars of Salmonella enterica revealed that specific mutant variants of FimH are common in host-adapted (systemically invasive) serovars. We have found that while the low-binding shear-dependent phenotype of the adhesin is preserved in broad host-range (usually systemically non-invasive) Salmonella, the majority of host-adapted serovars express FimH variants with one of two alternative phenotypes: a significantly increased binding to mannose (as in S. Typhi, S. Paratyphi C, S. Dublin and some isolates of S. Choleraesuis), or complete loss of the mannose-binding activity (as in S. Paratyphi B, S. Choleraesuis and S. Gallinarum). The functional diversification of FimH in host-adapted Salmonella results from recently acquired structural mutations. Many of the mutations are of a convergent nature indicative of strong positive selection. The high-binding phenotype of FimH that leads to increased bacterial adhesiveness to and invasiveness of epithelial cells and macrophages usually precedes acquisition of the non-binding phenotype. Collectively these observations suggest that activation or inactivation of mannose-specific adhesive properties in different systemically invasive serovars of Salmonella reflects their dynamic trajectories of adaptation to a life style in specific hosts. In conclusion, our study demonstrates that point mutations are the target of positive selection and, in addition to horizontal gene transfer and genome degradation events, can contribute to the differential pathoadaptive evolution of Salmonella. PMID:22685400

Blood invasiveness of Salmonella enterica as a function of age and serotype.

PubMed Central

Weinberger, M.; Andorn, N.; Agmon, V.; Cohen, D.; Shohat, T.; Pitlik, S. D.

2004-01-01

We explored the dual influence of the patient's age and the infecting serotype on the blood invasiveness patterns of non-Typhi Salmonella enterica (NTS). Blood invasiveness ratio (BIR) was calculated as the ratio between the number of blood and blood + stool isolates. Analysis of 14,951 NTS isolates showed that the BIR increased drastically above the age of 60 years, reaching levels 3.5-7 times higher compared to age group < 2 years. Different patterns of age-related invasiveness were observed for the five most common NTS serotypes (Enteritidis, Typhimurium, Virchow, Hadar, Infantis). Among children < 2 years, the BIR was highest for serotype Virchow and lowest for serotype Hadar, while in persons > or = 60 years it was highest for serotypes Enteritidis and lowest for serotype Infantis. The tendency of NTS serotypes to invade the bloodstream was significantly influenced by the patient's age, however the impact of age differed for various NTS serotypes. PMID:15635958

Feverlike Temperature is a Virulence Regulatory Cue Controlling the Motility and Host Cell Entry of Typhoidal Salmonella.

PubMed

Elhadad, Dana; McClelland, Michael; Rahav, Galia; Gal-Mor, Ohad

2015-07-01

Human infection with typhoidal Salmonella serovars causes a febrile systemic disease, termed enteric fever. Here we establish that in response to a temperature equivalent to fever (39 °C-42 °C) Salmonella enterica serovars Typhi, Paratyphi A, and Sendai significantly attenuate their motility, epithelial cell invasion, and uptake by macrophages. Under these feverlike conditions, the residual epithelial cell invasion of S. Paratyphi A occurs in a type III secretion system (T3SS) 1-independent manner and results in restrained disruption of epithelium integrity. The impaired motility and invasion are associated with down-regulation of T3SS-1 genes and class II and III (but not I) of the flagella-chemotaxis regulon. In contrast, we demonstrate up-regulation of particular Salmonella pathogenicity island 2 genes (especially spiC) and increased intraepithelial growth in a T3SS-2-dependent manner. These results indicate that elevated physiological temperature is a novel cue controlling virulence phenotypes in typhoidal serovars, which is likely to play a role in the distinct clinical manifestations elicited by typhoidal and nontyphoidal salmonellae. © The Author 2014. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Antibacterial effect of roselle extracts (Hibiscus sabadariffa), sodium hypochlorite and acetic acid against multidrug-resistant Salmonella strains isolated from tomatoes.

PubMed

Gutiérrez-Alcántara, E J; Rangel-Vargas, E; Gómez-Aldapa, C A; Falfan-Cortes, R N; Rodríguez-Marín, M L; Godínez-Oviedo, A; Cortes-López, H; Castro-Rosas, J

2016-02-01

Antibiotic-resistant Salmonella strains were isolated from saladette and red round type tomatoes, and an analysis done of the antibacterial activity of roselle calyx extracts against any of the identified strains. One hundred saladette tomato samples and 100 red round tomato samples were collected from public markets. Each sample consisted of four whole tomatoes. Salmonella was isolated from the samples by conventional culture procedure. Susceptibility to 16 antibiotics was tested for the isolated Salmonella strains by standard test. The antibacterial effect of four roselle calyx extracts (water, methanol, acetone and ethyl acetate), sodium hypochlorite and acetic acid against antibiotic-resistant Salmonella isolates was evaluated on contaminated tomatoes. Twenty-four Salmonella strains were isolated from 12% of each tomato type. Identified Salmonella serotypes were Typhimurium and Typhi. All isolated strains exhibited resistance to at least three antibiotics and some to as many as 12. Over contaminated tomatoes, the roselle calyx extracts produced a greater reduction (2-2·6 log) in antibiotic-resistant Salmonella strain concentration than sodium hypochlorite and acetic acid. The presence of multidrug-resistant Salmonella in vegetables is a significant public health concern. Multidrug-resistant Salmonella strains were isolated from raw tomatoes purchased in public markets in Mexico and challenged with roselle Hibiscus sabdariffa calyx extracts, sodium hypochlorite and acetic acid. On tomatoes, the extracts caused a greater reduction in the concentration of antibiotic-resistant Salmonella strains than sodium hypochlorite and acetic acid. Roselle calyx extracts are a potentially useful addition to disinfection procedures of raw tomatoes in the field, processing plants, restaurants and homes. © 2015 The Society for Applied Microbiology.

Structure, diversity, and mobility of the Salmonella pathogenicity island 7 family of integrative and conjugative elements within Enterobacteriaceae.

PubMed

Seth-Smith, Helena M B; Fookes, Maria C; Okoro, Chinyere K; Baker, Stephen; Harris, Simon R; Scott, Paul; Pickard, Derek; Quail, Michael A; Churcher, Carol; Sanders, Mandy; Harmse, Johan; Dougan, Gordon; Parkhill, Julian; Thomson, Nicholas R

2012-03-01

Integrative and conjugative elements (ICEs) are self-mobile genetic elements found in the genomes of some bacteria. These elements may confer a fitness advantage upon their host bacteria through the cargo genes that they carry. Salmonella pathogenicity island 7 (SPI-7), found within some pathogenic strains of Salmonella enterica, possesses features indicative of an ICE and carries genes implicated in virulence. We aimed to identify and fully analyze ICEs related to SPI-7 within the genus Salmonella and other Enterobacteriaceae. We report the sequence of two novel SPI-7-like elements, found within strains of Salmonella bongori, which share 97% nucleotide identity over conserved regions with SPI-7 and with each other. Although SPI-7 within Salmonella enterica serovar Typhi appears to be fixed within the chromosome, we present evidence that these novel elements are capable of excision and self-mobility. Phylogenetic analyses show that these Salmonella mobile elements share an ancestor which existed approximately 3.6 to 15.8 million years ago. Additionally, we identified more distantly related ICEs, with distinct cargo regions, within other strains of Salmonella as well as within Citrobacter, Erwinia, Escherichia, Photorhabdus, and Yersinia species. In total, we report on a collection of 17 SPI-7 related ICEs within enterobacterial species, of which six are novel. Using comparative and mutational studies, we have defined a core of 27 genes essential for conjugation. We present a growing family of SPI-7-related ICEs whose mobility, abundance, and cargo variability indicate that these elements may have had a large impact on the evolution of the Enterobacteriaceae.

A case of Salmonella enterica serotype typhi in a patient without a history of international travel.

PubMed

Byers, David K; Petersen, Kyle

2009-01-01

Typhoid fever, endemic in the developing world, is associated with international travel in developed nations. We present a case of Salmonella enterica infection in a patient without a history of international travel acquired from his traveling ex-wife. History of overseas travel in family members should be investigated when evaluating suspected cases.

Overview of the development of quinolone resistance in Salmonella species in China, 2005–2016

PubMed Central

Song, Qifa; Xu, Zhaojun; Gao, Hong; Zhang, Danyang

2018-01-01

Purpose Several factors contribute to the complexity of quinolone resistance in Salmonella, including >2000 different Salmonella serotypes, a variety of hosts for Salmonella, and wide use of quinolones in human beings and animals. We thus aimed to obtain an overview of the development of quinolone resistance and relevant molecular mechanisms of such a resistance in Salmonella species. Materials and methods A total of 1,776 Salmonella isolates were collected in Ningbo, China, between 2005 and 2016. Antimicrobial susceptibility to quinolone and relevant genetic mechanisms in these isolates were retrospectively analyzed. Results The ratio for ciprofloxacin (CIP) resistant:reduced CIP susceptible:CIP susceptible was 26:522:1,228. CIP resistance was found in nine of 51 serotypes: Derby, London, Kentucky, Indiana, Corvallis, Rissen, Hadar, Typhimurium, and Agona. Of 26 CIP-resistant isolates, all were concurrently resistant to ampicillin and 21 were also concurrently resistant to cefotaxime and produced extended-spectrum β-lactamase (ESBL). The minimal inhibitory concentration values were at three levels: 2–4 μg/mL (serotypes except for Kentucky and Indiana), 16 μg/mL (one Kentucky isolate), and >32 μg/mL (Indiana isolates). As with the three most common serotypes, Salmonella Typhi showed quickly increased prevalence of reduced CIP susceptibility in recent years, Salmonella Enteritidis remained at a high prevalence of reduced CIP susceptibility throughout the study period, and several isolates of Salmonella Typhimurium were resistant to CIP. Transferable plasmid-mediated quinolone resistance gene qnrB was only found in all CIP-resistant isolates. In contrast, gyrA mutations were often found in reduced CIP-susceptible isolates and were not necessarily found in all CIP-resistant isolates. Conclusion We conclude that in Salmonella, there exists a high prevalence of reduced CIP susceptibility and a low prevalence of CIP resistance, which focuses on several serotypes

Predictive Modeling for the Growth of Salmonella Enteritidis in Chicken Juice by Real-Time Polymerase Chain Reaction.

PubMed

Noviyanti, Fia; Hosotani, Yukie; Koseki, Shigenobu; Inatsu, Yasuhiro; Kawasaki, Susumu

2018-04-02

The goals of this study were to monitor the growth kinetics of Salmonella Enteritidis in chicken juice using real-time polymerase chain reaction (PCR) and to evaluate its efficacy by comparing the results with an experimental database. Salmonella Enteritidis was inoculated in chicken juice samples at an initial inoculum of 10 4 CFU/mL with inoculated samples incubated at six different temperatures (10, 15, 20, 25, 30, and 35°C). Sampling was carried out for 36 h to observe the growth of Salmonella Enteritidis. The total DNA was extracted from the samples, and the copy number of the Salmonella invasion gene (invA) was quantified by real-time PCR and converted to Salmonella Enteritidis cell concentration. Growth kinetics data were analyzed by the Baranyi and Roberts model to obtain growth parameters, whereas the Ratkowsky's square-root model was used to describe the effect of the interactions between growth parameters and temperature on the growth of Salmonella Enteritidis. The growth parameters of Salmonella Enteritidis obtained from an experiment conducted at a constant temperature were validated with growth data from chicken juice samples that were incubated under fluctuating temperature conditions between 5°C and 30°C for 30-min periods. A high correlation was observed between maximum growth rate (μ max ) and storage temperature, indicating that the real-time PCR-monitoring method provides a precise estimation of Salmonella Enteritidis growth in food material with a microbial flora. Moreover, the μ max data reflected data from microbial responses viewer database and ComBase. The results of this study suggested that real-time PCR monitoring provides a precise estimation of Salmonella Enteritidis growth in food materials with a background microbial flora.

Development of a multiplex qPCR in real time for quantification and differential diagnosis of Salmonella Gallinarum and Salmonella Pullorum.

PubMed

Rubio, Marcela da Silva; Penha Filho, Rafael Antonio Casarin; Almeida, Adriana Maria de; Berchieri, Angelo

2017-12-01

Currently there are 2659 Salmonella serovars. The host-specific biovars Salmonella Pullorum and Salmonella Gallinarum cause systemic infections in food-producing and wild birds. Fast diagnosis is crucial to control the dissemination in avian environments. The present work describes the development of a multiplex qPCR in real time using a low-cost DNA dye (SYBr Green) to identify and quantify these biovars. Primers were chosen based on genomic regions of difference (RoD) and optimized to control dimers. Primers pSGP detect both host-specific biovars but not other serovars and pSG and pSP differentiate biovars. Three amplicons showed different melting temperatures (Tm), allowing differentiation. The pSGP amplicon (97 bp) showed Tm of 78°C for both biovars. The pSG amplicon (273 bp) showed a Tm of 86.2°C for S. Gallinarum and pSP amplicon (260 bp) dissociated at 84.8°C for S. Pullorum identification. The multiplex qPCR in real time showed high sensitivity and was capable of quantifying 10 8 -10 1 CFU of these biovars.

Salmonella detection in poultry samples. Comparison of two commercial real-time PCR systems with culture methods for the detection of Salmonella spp. in environmental and fecal samples of poultry.

PubMed

Sommer, D; Enderlein, D; Antakli, A; Schönenbrücher, H; Slaghuis, J; Redmann, T; Lierz, M

2012-01-01

The efficiency of two commercial PCR methods based on real-time technology, the foodproof® Salmonella detection system and the BAX® PCR Assay Salmonella system was compared to standardized culture methods (EN ISO 6579:2002 - Annex D) for the detection of Salmonella spp. in poultry samples. Four sample matrices (feed, dust, boot swabs, feces) obtained directly from poultry flocks, as well as artificially spiked samples of the same matrices, were used. All samples were tested for Salmonella spp. using culture methods first as the gold standard. In addition samples spiked with Salmonella Enteridis were tested to evaluate the sensitivity of both PCR methods. Furthermore all methods were evaluated in an annual ring-trial of the National Salmonella Reference Laboratory of Germany. Salmonella detection in the matrices feed, dust and boot swabs were comparable in both PCR systems whereas the results from feces differed markedly. The quality, especially the freshness, of the fecal samples had an influence on the sensitivity of the real-time PCR and the results of the culture methods. In fresh fecal samples an initial spiking level of 100cfu/25g Salmonella Enteritidis was detected. Two-days-dried fecal samples allowed the detection of 14cfu/25g. Both real- time PCR protocols appear to be suitable for the detection of Salmonella spp. in all four matrices. The foodproof® system detected eight samples more to be positive compared to the BAX® system, but had a potential false positive result in one case. In 7-days-dried samples none of the methods was able to detect Salmonella likely through letal cell damage. In general the advantage of PCR analyses over the culture method is the reduction of working time from 4-5 days to only 2 days. However, especially for the analysis of fecal samples official validation should be conducted according to the requirement of EN ISO6579:2002 - Annex D.

Detection of viable Salmonella in ice cream by TaqMan real-time polymerase chain reaction assay combining propidium monoazide.

PubMed

Wang, Yuexia; Yang, Ming; Liu, Shuchun; Chen, Wanyi; Suo, Biao

2015-09-01

Real-time polymerase chain reaction (PCR) allows rapid detection of Salmonella in frozen dairy products, but it might cause a false positive detection result because it might amplify DNA from dead target cells as well. In this study, Salmonella-free frozen ice cream was initially inoculated with heat-killed Salmonella Typhimurium cells and stored at -18°C. Bacterial DNA extracted from the sample was amplified using TaqMan probe-based real-time PCR targeting the invA gene. Our results indicated that DNA from the dead cells remained stable in frozen ice cream for at least 20 days, and could produce fluorescence signal for real-time PCR as well. To overcome this limitation, propidium monoazide (PMA) was combined with real-time PCR. PMA treatment can effectively prevent PCR amplification from heat-killed Salmonella cells in frozen ice cream. The PMA real-time PCR assay can selectively detect viable Salmonella at as low as 10 3  CFU/mL. Combining 18 hours of pre-enrichment with the assay allows for the detection of viable Salmonella at 10 0  CFU/mL and avoiding the false-positive result of dead cells. The PMA real-time PCR assay provides an alternative specifically for detection of viable Salmonella in ice cream. However, when the PMA real-time PCR assay was evaluated in ice cream subjected to frozen storage, it obviously underestimated the contamination situation of viable Salmonella, which might lead to a false negative result. According to this result, the use of enrichment prior to PMA real-time PCR analysis remains as the more appropriate approach. Copyright © 2015. Published by Elsevier B.V.

What is the best immunization strategy for protecting African children against invasive Salmonella disease?

PubMed

Jeon, Hyon Jin; Pak, Gi Deok; Im, Justin; Owusu-Dabo, Ellis; Adu-Sarkodie, Yaw; Gassama Sow, Amy; Bassiahi, Abdramane Soura; Gasmelseed, Nagla; Keddy, Karen H; Bjerregaard-Andersen, Morten; Konings, Frank; Aseffa, Abraham; Crump, John A; Chon, Yun; Breiman, Robert F; Park, Se Eun; Cruz Espinoza, Ligia Maria; Seo, Hye Jin; May, Jürgen; Meyer, Christian G; Andrews, Jason R; Panzner, Ursula; von Kalckreuth, Vera; Wierzba, Thomas F; Rakotozandrindrainy, Raphaël; Dougan, Gordon; Levine, Myron M; Hombach, Joachim; Kim, Jerome H; Clemens, John D; Baker, Stephen; Marks, Florian

2018-05-09

The WHO recently prequalified a typhoid conjugate vaccine (TCV), recommending its use in persons aged ≥6 months to 45 years residing in typhoid fever (TF)-endemic areas. We now need to consider how TCVs can have the greatest impact in the most vulnerable populations in Africa. The Typhoid Fever Surveillance in Africa Program (TSAP) in 10 sub-Saharan African countries included blood culture-based surveillance in febrile people presenting at healthcare-facilities originating from defined catchment areas. The TF/invasive non-typhoidal Salmonella (iNTS) disease incidences were estimated for 0-10 year-old children in yearly increments. Salmonella Typhi and iNTS were the most frequently isolated pathogens, 135 and 94 cases were identified, respectively. Isolates (12 and 4, respectively) from Ethiopia, Senegal and South Africa were excluded due to person-years of observation (PYO) data absence. 37/123 (30.1%) TF and 71/90 (78.9%) iNTS disease cases occurred among individuals aged <5 years. No TF and 8/90 (8.9%) iNTS-infections were observed in children aged <9 months. The TF incidences (/100,000 PYO) for children aged <1 year and 1-<2 years were 5 and 39, respectively; the highest incidence was 304/100,000 PYO in 4-<5 year-old children. The iNTS incidence in the defined age groups ranged between 81 and 233/100,000 PYO, with the highest incidence in 1-<2 year-old children. Higher TF/iNTS disease incidences were observed in West Africa. The high TF burden observed in TSAP merits TCV introductions. Considering the additional iNTS disease burden, a trivalent vaccine targeting S. Typhi, S. Typhimurium, and S. Enteritidis may be a future solution.

False positive malaria rapid diagnostic test in returning traveler with typhoid fever.

PubMed

Meatherall, Bonnie; Preston, Keith; Pillai, Dylan R

2014-07-09

Rapid diagnostic tests play a pivotal role in the early diagnosis of malaria where microscopy or polymerase chain reaction are not immediately available. We report the case of a 39 year old traveler to Canada who presented with fever, headache, and abdominal pain after visiting friends and relatives in India. While in India, the individual was not ill and had no signs or symptoms of malaria. Laboratory testing upon his return to Canada identified a false positive malaria rapid diagnostic (BinaxNOW® malaria) result for P. falciparum with coincident Salmonella Typhi bacteraemia without rheumatoid or autoimmune factors. Rapid diagnostic test false positivity for malaria coincided with the presence or absence of Salmonella Typhi in the blood. Clinicians should be aware that Salmonella Typhi infection may result in a false positive malaria rapid diagnostic test. The mechanism of this cross-reactivity is not clear.

Effect of ionizing radiation on the quantitative detection of Salmonella using real-time PCR

NASA Astrophysics Data System (ADS)

Lim, Sangyong; Jung, Jinwoo; Kim, Minjeong; Ryu, Sangryeol; Kim, Dongho

2008-09-01

Food irradiation is an economically viable technology for inactivating foodborne pathogens, but irradiation can mask pathogens in unhygienically prepared food. The aim of this study was to investigate the effect of irradiation treatment on the detection of Salmonella using real-time PCR. Three commercially available kits were tested, of which the InstaGene Matrix procedure was most effective in preparing template DNA from Salmonella exposed to radiation in broth culture. The minimum level of detection by real-time PCR combined with InstaGene Matrix was 3 log units of Salmonella per milliliter. However, when pure cultures of Salmonella were irradiated at 3 and 5 kGy, the cycle threshold ( CT) increased 1-1.5-fold compared to irradiation at 0 and 1 kGy. This indicated that irradiation treatment may result in an underestimation of bacterial counts due to radiation-induced DNA lesions. We also compared CT values in inoculated chicken homogenates before and after irradiation, which in this model caused a 1.3-3.3-fold underestimation of bacterial counts with respect to irradiation dose.

Effects of Chicken Litter Storage Time and Ammonia Content on Thermal Resistance of Desiccation-Adapted Salmonella spp.

PubMed

Chen, Zhao; Wang, Hongye; Ionita, Claudia; Luo, Feng; Jiang, Xiuping

2015-10-01

Broiler chicken litter was kept as a stacked heap on a poultry farm, and samples were collected up to 9 months of storage. Chicken litter inoculated with desiccation-adapted Salmonella cells was heat-treated at 75, 80, 85, and 150°C. Salmonella populations decreased in all these samples during heat treatment, and the inactivation rates became lower in chicken litter when storage time was extended from 0 to 6 months. There was no significant difference (P > 0.05) in thermal resistance of Salmonella in 6- and 9-month litter samples, indicating that a threshold for thermal resistance was reached after 6 months. Overall, the thermal resistance of Salmonella in chicken litter was affected by the storage time of the litter. The changes in some chemical, physical, and microbiological properties during storage could possibly contribute to this difference. Moisture and ammonia could be two of the most significant factors influencing the thermal resistance of Salmonella cells in chicken litter. Our results emphasize the importance of adjusting time and temperature conditions for heat processing chicken litter when it is removed from the chicken house at different time intervals. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Effects of Chicken Litter Storage Time and Ammonia Content on Thermal Resistance of Desiccation-Adapted Salmonella spp.

PubMed Central

Chen, Zhao; Wang, Hongye; Ionita, Claudia; Luo, Feng

2015-01-01

Broiler chicken litter was kept as a stacked heap on a poultry farm, and samples were collected up to 9 months of storage. Chicken litter inoculated with desiccation-adapted Salmonella cells was heat-treated at 75, 80, 85, and 150°C. Salmonella populations decreased in all these samples during heat treatment, and the inactivation rates became lower in chicken litter when storage time was extended from 0 to 6 months. There was no significant difference (P > 0.05) in thermal resistance of Salmonella in 6- and 9-month litter samples, indicating that a threshold for thermal resistance was reached after 6 months. Overall, the thermal resistance of Salmonella in chicken litter was affected by the storage time of the litter. The changes in some chemical, physical, and microbiological properties during storage could possibly contribute to this difference. Moisture and ammonia could be two of the most significant factors influencing the thermal resistance of Salmonella cells in chicken litter. Our results emphasize the importance of adjusting time and temperature conditions for heat processing chicken litter when it is removed from the chicken house at different time intervals. PMID:26209673

Diagnostics for invasive Salmonella infections: current challenges and future directions

PubMed Central

Andrews, Jason R.; Ryan, Edward T.

2015-01-01

Invasive Salmonellosis caused by Salmonella enterica serotype Typhi or Paratyphi A, B, C, or invasive non-typhoidal Salmonella serotypes, is an immensely important disease cluster for which reliable, rapid diagnostic tests are not available. Blood culture remains the gold standard but is insensitive, slow, and resource-intensive. Existing molecular diagnostics have poor sensitivity due to the low organism burden in bodily fluids. Commercially available serologic tests for typhoidal Salmonella have had limited sensitivity and specificity. In high burden, resource-limited settings, reliance on clinical diagnosis or inaccurate tests often results in frequent, unnecessary treatment, which contributes selective pressure for the emergence of antimicrobial resistance. This practice also results in inadequate therapy for other etiologies of acute febrile illnesses, including leptospirosis and rickettsial infections. A number of novel serologic, molecular, transcriptomic and metabolomic approaches to diagnostics are under development. Target product profiles that outline specific needs may focus development and investment, and establish benchmarks for accuracy, cost, speed, and portability of new diagnostics. Of note, a critical barrier to diagnostic assay rollout will be the low cost and low perceived harm of empiric therapy on behalf of providers and patients, which leaves few perceived incentives to utilize diagnostics. Approaches that align incentives with societal goals of limiting inappropriate antimicrobial use, such as subsidizing diagnostics, may be essential for stimulating development and uptake of such assays in resource-limited settings. New diagnostics for invasive Salmonellosis should be developed and deployed alongside diagnostics for alternative etiologies of acute febrile illnesses to improve targeted use of antibiotics. PMID:25937611

Diagnostics for invasive Salmonella infections: Current challenges and future directions.

PubMed

Andrews, Jason R; Ryan, Edward T

2015-06-19

Invasive Salmonellosis caused by Salmonella enterica serotype Typhi or Paratyphi A, B, C, or invasive non-typhoidal Salmonella serotypes, is an immensely important disease cluster for which reliable, rapid diagnostic tests are not available. Blood culture remains the gold standard but is insensitive, slow, and resource-intensive. Existing molecular diagnostics have poor sensitivity due to the low organism burden in bodily fluids. Commercially available serologic tests for typhoidal Salmonella have had limited sensitivity and specificity. In high burden, resource-limited settings, reliance on clinical diagnosis or inaccurate tests often results in frequent, unnecessary treatment, which contributes selective pressure for the emergence of antimicrobial resistance. This practice also results in inadequate therapy for other etiologies of acute febrile illnesses, including leptospirosis and rickettsial infections. A number of novel serologic, molecular, transcriptomic and metabolomic approaches to diagnostics are under development. Target product profiles that outline specific needs may focus development and investment, and establish benchmarks for accuracy, cost, speed, and portability of new diagnostics. Of note, a critical barrier to diagnostic assay rollout will be the low cost and low perceived harm of empiric therapy on behalf of providers and patients, which leaves few perceived incentives to utilize diagnostics. Approaches that align incentives with societal goals of limiting inappropriate antimicrobial use, such as subsidizing diagnostics, may be essential for stimulating development and uptake of such assays in resource-limited settings. New diagnostics for invasive Salmonellosis should be developed and deployed alongside diagnostics for alternative etiologies of acute febrile illnesses to improve targeted use of antibiotics. Copyright © 2015. Published by Elsevier Ltd.

Rapid real-time PCR methods to distinguish Salmonella Enteritidis wildtype field isolates from vaccine strains Salmovac SE/Gallivac SE and AviPro SALMONELLA VAC E.

PubMed

Maurischat, Sven; Szabo, Istvan; Baumann, Beatrice; Malorny, Burkhard

2015-05-01

Salmonella enterica serovar Enteritidis is a major non-typhoid Salmonella serovar causing human salmonellosis mainly associated with the consumption of poultry and products thereof. To reduce infections in poultry, S. Enteritidis live vaccine strains AviPro SALMONELLA VAC E and Salmovac SE/Gallivac SE have been licensed and used in several countries worldwide. To definitively diagnose a S. Enteritidis contamination in vaccinated herds a reliable and fast method for the differentiation between vaccine and wildtype field isolates is required. In this study, we developed and validated real-time PCR (qPCR) assays to distinguish those variants genetically. Suitable target sequences were identified by whole genome sequencing (WGS) using the Illumina MiSeq system. SNP regions in kdpA and nhaA proved to be most useful for differentiation of AviPro SALMONELLA VAC E and Salmovac SE/Gallivac SE, respectively, from wildtype strains. For each vaccine strain one TaqMan-qPCR assay and one alternative approach using High Resolution Melting (HRM) analysis was designed. All 30 Salmovac SE and 7 AviPro SALMONELLA VAC E vaccine strain reisolates tested were correctly identified by both approaches (100% inclusivity). Furthermore, all 137 (TaqMan) and 97 (HRM) Salmonella non-vaccine and related Enterobacteriaceae strains tested were excluded (100% exclusivity). The analytical detection limits were determined to be approx. 10(2) genome copies/reaction for the TaqMan and 10(4) genome copies/reaction for the HRM approach. The real-time PCR assays proved to be a reliable and fast alternative to the cultural vaccine strain identification tests helping decision makers in control measurements to take action within a shorter period of time. Copyright © 2015 Elsevier B.V. All rights reserved.

Direct evidence of Rickettsia typhi infection in Rhipicephalus sanguineus ticks and their canine hosts.

PubMed

Dzul-Rosado, Karla; Lugo-Caballero, Cesar; Tello-Martin, Raul; López-Avila, Karina; Zavala-Castro, Jorge

2017-01-01

Murine typhus is a rickettsiosis caused by Rickettsia typhi , whose transmission is carried out by rat fleas in urban settlements as classically known, but it also has been related to cat fleas in a sub-urban alternative cycle that has been suggested by recent reports. These studies remarks that in addition to rats, other animals like cats, opossums and dogs could be implied in the transmission of Rickettsia typhi as infected fleas obtained from serologically positive animals have been detected in samples from endemic areas. In Mexico, the higher number of murine typhus cases have been detected in the Yucatan peninsula, which includes a great southeastern region of Mexico that shows ecologic characteristics similar to the sub-urban alternative cycle recently described in Texas and California at the United States. To find out which are the particular ecologic characteristics of murine typhus transmission in this region, we analyzed blood and Rhipicephalus sanguineus ticks obtained from domestic dogs by molecular approaches, demonstrating that both samples were infected by Rickettsia typhi . Following this, we obtained isolates that were analyzed by genetic sequencing to corroborate this infection in 100% of the analyzed samples. This evidence suggests for the first time that ticks and dogs could be actively participating in the transmission of murine typhus, in a role that requires further studies for its precise description.

The inhibitory effect of natural bioactives on the growth of pathogenic bacteria

PubMed Central

Kim, Ji-Sun

2007-01-01

The objective of this study was to evaluate the inhibitory activity of natural products, against growth of Escherichia coli (ATCC 25922) and Salmonella typhimurium (KCCM 11862). Chitosan, epigallocatechin gallate (EGCG), and garlic were used as natural bioactives for antibacterial activity. The testing method was carried out according to the disk diffusion method. All of chitosan, EGCG, and garlic showed inhibitory effect against the growth of E. coli and Salmonella typhi. To evaluate the antibacterial activity of natural products during storage, chicken skins were inoculated with 106 of E. coli or Salmonella typhi. The inoculated chicken skins, treated with 0.5, 1, or 2% natural bioactives, were stored during 8 day at 4℃. The numbers of microorganisms were measured at 8 day. Both chitosan and EGCG showed significant decrease in the number of E. coli and Salmonella typhi in dose dependent manner (P < 0.05). These results suggest that natural bioactives such as chitosan, EGCG may be possible to be used as antimicrobial agents for the improvement of food safety. PMID:20368950

Molecular evidence of Rickettsia typhi infection in dogs from a rural community in Yucatán, México.

PubMed

Martínez-Ortiz, Daly; Torres-Castro, Marco; Koyoc-Cardeña, Edgar; López, Karina; Panti-May, Alonso; Rodríguez-Vivas, Iván; Puc, Adriano; Dzul, Karla; Zavala-Castro, Jorge; Medina-Barreiro, Anuar; Chablé-Santos, Juan; Manrique-Saide, Pablo

2016-02-23

Rickettsia typhi causes murine or endemic typhus, which is transmitted to humans primarily through flea bites contaminated with feces. Synanthropic and domestic animals also contribute to the infection cycle of R. typhi. Cases of murine typhus in humans were reported in the rural community of Bolmay, Yucatán, México, between 2007 and 2010.  To identify the presence of R. typhi and estimate the frequency of infection in dogs from Bolmay, México, a locality with previous reports of murine typhus in humans.  Whole blood samples were taken from 128 dogs. Total DNA was extracted for use in the polymerase chain reaction (PCR) to amplify fragments of the 17 kDa and omp B genes and confirms the presence of Rickettsia spp. The reaction products were sequenced, and alignment analysis was performed using the BLAST tool.  The frequency of R. typhi infection in dogs was 5.5 % (7/128). The alignment identified 99% and 100% homology to the R. typhi 17 kDa and omp B genes, respectively.  We confirmed the presence of R. typhi in dogs in the studied community but at a low frequency. However, there is potential risk of transmission to humans.

Influence of On-farm pig Salmonella status on Salmonella Shedding at Slaughter.

PubMed

Casanova-Higes, A; Andrés-Barranco, S; Mainar-Jaime, R C

2017-08-01

The risk of Salmonella shedding among pigs at slaughter with regard to their previous on-farm Salmonella status was assessed in a group of pigs from a farm from NE of Spain. A total of 202 pigs that had been serologically monitored monthly during the fattening period and from which mesenteric lymph nodes (MLN) and faecal (SFEC) samples were collected at slaughter for Salmonella isolation were included. A repeated-measures anova was used to assess the relationship between mean OD% values during the fattening period and sampling time and bacteriology on MLN and SFEC. Pigs were also grouped into four groups, that is pigs seronegative during the fattening period and Salmonella negative in MLN (group A; n = 69); pigs seronegative during the fattening period but Salmonella positive in MLN (B; n = 36); pigs seropositive at least once and Salmonella positive in MLN (C; n = 50); and pigs seropositive at least once but Salmonella negative in (D; n = 47). Pigs shedding at slaughter seroconverted much earlier and showed much higher mean OD% values than non-shedders pigs. The proportion of Salmonella shedders in groups A and D was high and similar (26.1% and 29.8%, respectively), but significantly lower than that for groups B and C. The odds of shedding Salmonella for groups B and C were 4.8 (95% CI = 1.5-15.5) and 20.9 (3.7-118) times higher, respectively, when compared to A. It was concluded that a large proportion of Salmonella seronegative pigs may shed Salmonella at slaughter, which would be likely associated to previous exposure with contaminated environments (i.e. transport and lairage). For pigs already infected at farm, the likelihood of shedding Salmonella was much higher and may depend on whether the bacterium has colonized the MLN or not. The odds of shedding Salmonella spp. were always much higher for pigs in which Salmonella was isolated from MLN. © 2016 Blackwell Verlag GmbH.

Changing trends of culture-positive typhoid fever and antimicrobial susceptibility in a tertiary care North Indian Hospital over the last decade.

PubMed

Sharma, Priyanka; Dahiya, Sushila; Manral, Neelam; Kumari, Bhavana; Kumar, Sambuddha; Pandey, Sangeeta; Sood, Seema; Das, Bimal Kumar; Kapil, Arti

2018-01-01

The present study was undertaken to analyse the trend in prevalence of culture-positive typhoid fever during the last decade and to determine antimicrobial susceptibility profile of Salmonella Typhi and Salmonella Paratyphi A isolated from patients of enteric fever presenting to our hospital. All the culture-positive enteric fever cases during 2005-2016 presenting to our Hospital were included in the study. Antimicrobial susceptibility was done against chloramphenicol, amoxicillin, co-trimoxazole, ciprofloxacin, ofloxacin, levofloxacin, pefloxacin, ceftriaxone and azithromycin as per corresponding CLSI guidelines for each year. We also analysed the proportion of culture positivity during 1993-2016 in light of the antibiotic consumption data from published literature. A total of 1066 strains-S. Typhi (772) and S. Paratyphi A (294) were isolated from the blood cultures during the study. A maximum number of cases were found in July-September. Antimicrobial susceptibility for chloramphenicol, amoxicillin and co-trimoxazole was found to be 87.9%, 75.5%, 87.3% for S. Typhi and 94.2%, 90.1% and 94.2% for S. Paratyphi A, respectively. Ciprofloxacin, ofloxacin and levofloxacin susceptibility were 71.3%, 70.8% and 70.9% for S. Typhi and 58.1%, 57.4% and 57.1% for S. Paratyphi A, respectively. Azithromycin susceptibility was 98.9% in S. Typhi. Although susceptibility to ceftriaxone and cefixime was 100% in our isolates, there is a continuous increase in ceftriaxone minimum inhibitory concentration (MIC) 50 and MIC 90 values over the time. The proportion of blood culture-positive cases during 1993-2016 ranged from a minimum of 0.0006 in 2014 to a maximum of 0.0087 in 1999. We found that the most common etiological agent of enteric fever is S. Typhi causing the majority of cases from July to October in our region. MIC to ceftriaxone in typhoidal salmonellae is creeping towards resistance and more data are needed to understand the azithromycin susceptibility.

Utilization of plant-derived recombinant human β-defensins (hBD-1 and hBD-2) for averting salmonellosis.

PubMed

Patro, Sunita; Maiti, Soumitra; Panda, Santosh Kumar; Dey, Nrisingha

2015-04-01

We describe the use of plant-made β-defensins as effective antimicrobial substances for controlling salmonellosis, a deadly infection caused by Salmonella typhimurium (referred to further as S. typhi). Human β-defensin-1 (hBD-1) and -2 (hBD-2) were expressed under the control of strong constitutive promoters in tobacco plants, and bio-active β-defensins were successfully extracted. In the in vitro studies, enriched recombinant plant-derived human β-defensin-1 (phBD-1) and -2 (phBD-2) obtained from both T1 and T2 transgenic plants showed significant antimicrobial activity against Escherichia coli and S. typhi when used individually and in various combinations. The 2:1 peptide combination of phBD-1:phBD-2 with peptides isolated from T1-and T2-generation plants reduced the growth of S. typhi by 96 and 85 %, respectively. In vivo studies employing the mouse model (Balb/c) of Salmonella infection clearly demonstrated that the administration of plant-derived defensins individually and in different combinations enhanced the mean survival time of Salmonella-infected animals. When treatment consisted of the 2:1 phBD-1:phBD-2 combination, approximately 50 % of the infected mice were still alive at 206 h post-inoculation; the lowest number of viable S. typhi was observed in the liver and spleen of infected animals. We conclude that plant-made recombinant β-defensins (phBD-1 and phBD-2) are promising antimicrobial substances and have the potential to become additional tools against salmonellosis, particularly when used in combination.

Enteritis

MedlinePlus

... enteritis E coli enteritis Food poisoning Radiation enteritis Salmonella enteritis Shigella enteritis Staph aureus food poisoning Symptoms ... store food that needs to stay chilled. Images Salmonella typhi organism Yersinia enterocolitica organism Campylobacter jejuni organism ...

The emergence and outbreak of multidrug-resistant typhoid fever in China.

PubMed

Yan, Meiying; Li, Xinlan; Liao, Qiaohong; Li, Fang; Zhang, Jing; Kan, Biao

2016-06-22

Typhoid fever remains a severe public health problem in developing countries. The emergence of resistant typhoid, particularly multidrug-resistant typhoid infections, highlights the necessity of monitoring the resistance characteristics of this invasive pathogen. In this study, we report a typhoid fever outbreak caused by multidrug-resistant Salmonella enterica serovar Typhi strains with an ACSSxtT pattern. Resistance genes conferring these phenotypes were harbored by a large conjugative plasmid, which increases the threat of Salmonella Typhi and thus requires close surveillance for dissemination of strains containing such genes.

Proteomics Analysis of the Causative Agent of Typhoid Fever

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ansong, Charles; Yoon, Hyunjin; Norbeck, Angela D.

2008-02-01

Typhoid fever is a potentially fatal disease caused by the bacterial pathogen Salmonella enterica serovar Typhi (S. typhi). S. typhi infection is a complex process that involves numerous bacterially-encoded virulence determinants, and these are thought to confer both stringent human host specificity and a high mortality rate. In the present study we used a liquid chromatography-mass spectrometry (LC-MS) based proteomics strategy to investigate the proteome of logarithmic, stationary phase, and low pH/low magnesium (MgM) S. typhi cultures. This represents the first large scale comprehensive characterization of the S. typhi proteome. Our analysis identified a total of 2066 S. typhi proteins.more » In an effort to identify putative S. typhi-specific virulence factors, we then compared our S. typhi results to those obtained in a previously published study of the S. typhimurium proteome under similar conditions (Adkins J.N. et al (2006) Mol Cell Prot). Comparative proteomic analysis of S. typhi (strain Ty2) and S. typhimurium (strains LT2 and 14028) revealed a subset of highly expressed proteins unique to S. typhi that were exclusively detected under conditions that mimic the infective state in macrophage cells. These proteins included CdtB, HlyE, and a conserved protein encoded by t1476. The differential expression of selected proteins was confirmed by Western blot analysis. Taken together with the current literature, our observations suggest that this subset of proteins may play a role in S. typhi pathogenesis and human host specificity. In addition, we observed products of the biotin (bio) operon displayed a higher abundance in the more virulent strains S. typhi-Ty2 and S. typhimurium-14028 compared to the virulence attenuated S. typhimurium strain LT2, suggesting bio proteins may contribute to Salmonella pathogenesis.« less

Examining the Link between Biofilm Formation and the Ability of Pathogenic Salmonella Strains to Colonize Multiple Host Species

PubMed Central

MacKenzie, Keith D.; Palmer, Melissa B.; Köster, Wolfgang L.; White, Aaron P.

2017-01-01

Salmonella are important pathogens worldwide and a predominant number of human infections are zoonotic in nature. The ability of strains to form biofilms, which is a multicellular behavior characterized by the aggregation of cells, is predicted to be a conserved strategy for increased persistence and survival. It may also contribute to the increasing number of infections caused by ingestion of contaminated fruits and vegetables. There is a correlation between biofilm formation and the ability of strains to colonize and replicate within the intestines of multiple host species. These strains predominantly cause localized gastroenteritis infections in humans. In contrast, there are salmonellae that cause systemic, disseminated infections in a select few host species; these “invasive” strains have a narrowed host range, and most are unable to form biofilms. This includes host-restricted Salmonella serovar Typhi, which are only able to infect humans, and atypical gastroenteritis strains associated with the opportunistic infection of immunocompromised patients. From the perspective of transmission, biofilm formation is advantageous for ensuring pathogen survival in the environment. However, from an infection point of view, biofilm formation may be an anti-virulence trait. We do not know if the capacity to form biofilms prevents a strain from accessing the systemic compartments within the host or if loss of the biofilm phenotype reflects a change in a strain’s interaction with the host. In this review, we examine the connections between biofilm formation, Salmonella disease states, degrees of host adaptation, and how this might relate to different transmission patterns. A better understanding of the dynamic lifecycle of Salmonella will allow us to reduce the burden of livestock and human infections caused by these important pathogens. PMID:29159172

Liver Necrosis and Lethal Systemic Inflammation in a Murine Model of Rickettsia typhi Infection: Role of Neutrophils, Macrophages and NK Cells.

PubMed

Papp, Stefanie; Moderzynski, Kristin; Rauch, Jessica; Heine, Liza; Kuehl, Svenja; Richardt, Ulricke; Mueller, Heidelinde; Fleischer, Bernhard; Osterloh, Anke

2016-08-01

Rickettsia (R.) typhi is the causative agent of endemic typhus, an emerging febrile disease that is associated with complications such as pneumonia, encephalitis and liver dysfunction. To elucidate how innate immune mechanisms contribute to defense and pathology we here analyzed R. typhi infection of CB17 SCID mice that are congenic to BALB/c mice but lack adaptive immunity. CB17 SCID mice succumbed to R. typhi infection within 21 days and showed high bacterial load in spleen, brain, lung, and liver. Most evident pathological changes in R. typhi-infected CB17 SCID mice were massive liver necrosis and splenomegaly due to the disproportionate accumulation of neutrophils and macrophages (MΦ). Both neutrophils and MΦ infiltrated the liver and harbored R. typhi. Both cell populations expressed iNOS and produced reactive oxygen species (ROS) and, thus, exhibited an inflammatory and bactericidal phenotype. Surprisingly, depletion of neutrophils completely prevented liver necrosis but neither altered bacterial load nor protected CB17 SCID mice from death. Furthermore, the absence of neutrophils had no impact on the overwhelming systemic inflammatory response in these mice. This response was predominantly driven by activated MΦ and NK cells both of which expressed IFNγ and is considered as the reason of death. Finally, we observed that iNOS expression by MΦ and neutrophils did not correlate with R. typhi uptake in vivo. Moreover, we demonstrate that MΦ hardly respond to R. typhi in vitro. These findings indicate that R. typhi enters MΦ and also neutrophils unrecognized and that activation of these cells is mediated by other mechanisms in the context of tissue damage in vivo.

The emergence and outbreak of multidrug-resistant typhoid fever in China

PubMed Central

Yan, Meiying; Li, Xinlan; Liao, Qiaohong; Li, Fang; Zhang, Jing; Kan, Biao

2016-01-01

Typhoid fever remains a severe public health problem in developing countries. The emergence of resistant typhoid, particularly multidrug-resistant typhoid infections, highlights the necessity of monitoring the resistance characteristics of this invasive pathogen. In this study, we report a typhoid fever outbreak caused by multidrug-resistant Salmonella enterica serovar Typhi strains with an ACSSxtT pattern. Resistance genes conferring these phenotypes were harbored by a large conjugative plasmid, which increases the threat of Salmonella Typhi and thus requires close surveillance for dissemination of strains containing such genes. PMID:27329848

Comparison of CHROMagar Salmonella Medium and Xylose-Lysine-Desoxycholate and Salmonella-Shigella Agars for Isolation of Salmonella Strains from Stool Samples

PubMed Central

Maddocks, Susan; Olma, Tom; Chen, Sharon

2002-01-01

The growth and appearance of 115 stock Salmonella isolates on a new formulation of CHROMagar Salmonella (CAS) medium were compared to those on xylose-lysine-desoxycholate agar (XLD), Salmonella-Shigella agar (SS), and Hektoen enteric agar (HEA) media. CAS medium was then compared prospectively to XLD and SS for the detection and presumptive identification of Salmonella strains in 500 consecutive clinical stool samples. All stock Salmonella isolates produced typical mauve colonies on CAS medium. Nine Salmonella strains were isolated from clinical specimens. The sensitivities for the detection of salmonellae after primary plating on CAS medium and the combination of XLD and SS after enrichment were 100%. The specificity for the detection of salmonellae after primary plating on CAS medium (83%) was significantly (P < 0.0001) higher than that after primary plating on the combination of SS and XLD media (55%) (a 28% difference in rates; 95% confidence interval, 23.0 to 34%). Twenty-nine non-Salmonella organisms produced mauve colonies on CAS medium, including 17 Candida spp. (59%) and 8 Pseudomonas spp. (28%). These were easily excluded as salmonellae by colony morphology, microscopic examination of a wet preparation, or oxidase testing. One biochemically inert Escherichia coli isolate required further identification to differentiate it from Salmonella spp. The use of plating on CAS medium demonstrated high levels of sensitivity and specificity and reduced the time to final identification of Salmonella spp., resulting in substantial cost savings. It can be recommended for use for the primary isolation of Salmonella spp. from stool specimens. Other media (e.g., XLD) are required to detect Shigella spp. concurrently. PMID:12149365

Isolation and characterization of polyvalent bacteriophages infecting multi drug resistant Salmonella serovars isolated from broilers in Egypt.

PubMed

Mahmoud, Mayada; Askora, Ahmed; Barakat, Ahmed Barakat; Rabie, Omar El-Farouk; Hassan, Sayed Emam

2018-02-02

In this study, we isolated and characterized three phages named as Salmacey1, Salmacey2 and Salmacey3, infecting multi drug resistant Salmonella serovars isolated from broilers in Egypt. The most prevalent Salmonella serovars were S. typhimurium, S. enteritidis, and S. kentucky. All these Salmonella serovars were found to be resistant to more than two of the ten antimicrobial agents tested. Only S. kentucky was found to be resistant to seven antimicrobial agents. Examination of these phage particles by transmission electron microscopy (TEM), demonstrated that two phages (Salmacey1, Salmacey2) were found to belong to family Siphoviridae, and Salmacey3 was assigned to the family Myoviridae. The results of host range assay revealed that these bacteriophages were polyvalent and thus capable of infecting four strains of Salmonella serovars and Citrobacter freundii. Moreover, the two phages (Salmacey1, Salmacey2) had a lytic effect on Enterobacter cloacae and Salmacey3 was able to infect E. coli. All phages could not infect S. para Typhi, Staphylococus aureus and Bacillus cereus. One-step growth curves of bacteriophages revealed that siphovirus phages (Salmacey1, Salmacey2) have burst size (80 and 90pfu per infected cell with latent period 35min and 40min respectively), and for the myovirus Salmacey3 had a burst size 110pfu per infected cell with latent period 60min. Molecular analyses indicated that these phages contained double-stranded DNA genomes. The lytic activity of the phages against the most multidrug resistant serovars S. kentucky as host strain was evaluated. The result showed that these bacteriophages were able to completely stop the growth of S. kentucky in vitro. These results suggest that phages have a high potential for phage application to control Salmonella serovars isolated from broilers in Egypt. Copyright © 2017. Published by Elsevier B.V.

Inactivation of Salmonella Senftenberg, Salmonella Typhimurium and Salmonella Tennessee in peanut butter by 915 MHz microwave heating.

PubMed

Song, Won-Jae; Kang, Dong-Hyun

2016-02-01

This study evaluated the efficacy of a 915 MHz microwave with 3 different levels to inactivate 3 serovars of Salmonella in peanut butter. Peanut butter inoculated with Salmonella enterica serovar Senftenberg, S. enterica serovar Typhimurium and S. enterica serovar Tennessee were treated with a 915 MHz microwave with 2, 4 and 6 kW and acid and peroxide values and color changes were determined after 5 min of microwave heating. Salmonella populations were reduced with increasing treatment time and treatment power. Six kW 915 MHz microwave treatment for 5 min reduced these three Salmonella serovars by 3.24-4.26 log CFU/g. Four and two kW 915 MHz microwave processing for 5 min reduced these Salmonella serovars by 1.14-1.48 and 0.15-0.42 log CFU/g, respectively. Microwave treatment did not affect acid, peroxide, or color values of peanut butter. These results demonstrate that 915 MHz microwave processing can be used as a control method for reducing Salmonella in peanut butter without producing quality deterioration. Copyright © 2015 Elsevier Ltd. All rights reserved.

Typhoid fever.

PubMed

Wain, John; Hendriksen, Rene S; Mikoleit, Matthew L; Keddy, Karen H; Ochiai, R Leon

2015-03-21

Control of typhoid fever relies on clinical information, diagnosis, and an understanding for the epidemiology of the disease. Despite the breadth of work done so far, much is not known about the biology of this human-adapted bacterial pathogen and the complexity of the disease in endemic areas, especially those in Africa. The main barriers to control are vaccines that are not immunogenic in very young children and the development of multidrug resistance, which threatens efficacy of antimicrobial chemotherapy. Clinicians, microbiologists, and epidemiologists worldwide need to be familiar with shifting trends in enteric fever. This knowledge is crucial, both to control the disease and to manage cases. Additionally, salmonella serovars that cause human infection can change over time and location. In areas of Asia, multidrug-resistant Salmonella enterica serovar Typhi (S Typhi) has been the main cause of enteric fever, but now S Typhi is being displaced by infections with drug-resistant S enterica serovar Paratyphi A. New conjugate vaccines are imminent and new treatments have been promised, but the engagement of local medical and public health institutions in endemic areas is needed to allow surveillance and to implement control measures. Copyright © 2015 Elsevier Ltd. All rights reserved.

Lest We Forget: A Critical Analysis of Bioterrorist Incidents, National Exercises, and U.S. Prevention, Response and Recovery Strategies

DTIC Science & Technology

2011-04-01

American Type Culture Collection (ATCC), including Salmonella typhi (causes typhoid fever), Fancisella tularensis (causes tularemia ), Salmonella...incident, the Rajneesh cult obtained the agents on which it experimented, and Iraq obtained some of its lethal strains of anthrax, tularemia and

Inclusivity, exclusivity and limit of detection of commercially available real-time PCR assays for the detection of Salmonella.

PubMed

Margot, H; Stephan, R; Guarino, S; Jagadeesan, B; Chilton, D; O'Mahony, E; Iversen, C

2013-08-01

The traditional cultural detection of Salmonella spp. is both time- and labour-intensive. Salmonella is often a release criterion for the food industry and time to result is therefore an important factor. Storage of finished products and raw materials can be costly and may adversely impact available shelf-life. The application of real-time PCR for the detection of Salmonella spp. in food samples enables a potential time-saving of up to four days. The advancement of real-time PCR coupled with the development of commercially available systems in different formats has made this technology accessible for laboratories in an industrial environment. Ideally these systems are reliable and rapid as well as easy to use. The current study represents a comparative evaluation of seven commercial real-time PCR systems for the detection of Salmonella. Forty-nine target and twenty-nine non-target strains were included in the study to assess inclusivity and exclusivity. The limit of detection for each of the method was determined in four different food products. All systems evaluated were able to correctly identify the 49 Salmonella strains. Nevertheless, false positive results (Citrobacter spp.) were obtained with four of the seven systems. In milk powder and bouillon powder, the limit of detection was similar for all systems, suggesting a minimal matrix effect with these samples. Conversely, for black tea and cocoa powder some systems were prone to inhibition from matrix components. Up to 100% of the samples were inhibited using the proprietary extracts but inhibition could be reduced considerably by application of a DNA clean-up kit. Copyright © 2013 Elsevier B.V. All rights reserved.

Rectal swab sampling followed by an enrichment culture-based real-time PCR assay to detect Salmonella enterocolitis in children.

PubMed

Lin, L-H; Tsai, C-Y; Hung, M-H; Fang, Y-T; Ling, Q-D

2011-09-01

Although routine bacterial culture is the traditional reference standard method for the detection of Salmonella infection in children with diarrhoea, it is a time-consuming procedure that usually only gives results after 3-4 days. Some molecular detection methods can improve the turn-around time to within 24 h, but these methods are not applied directly from stool or rectal swab specimens as routine diagnostic methods for the detection of gastrointestinal pathogens. In this study, we tested the feasibility of a bacterial enrichment culture-based real-time PCR assay method for detecting and screening for diarrhoea in children caused by Salmonella. Our results showed that the minimum real-time PCR assay time required to detect enriched bacterial culture from a swab was 3 h. In all children with suspected Salmonella diarrhoea, the enrichment culture-based real-time PCR achieved 85.4% sensitivity and 98.1% specificity, as compared with the 53.7% sensitivity and 100% specificity of detection with the routine bacterial culture method. We suggest that rectal swab sampling followed by enrichment culture-based real-time PCR is suitable as a rapid method for detecting and screening for Salmonella in paediatric patients. © 2011 The Authors. Clinical Microbiology and Infection © 2011 European Society of Clinical Microbiology and Infectious Diseases.

Rapid detection of Salmonella in pet food: design and evaluation of integrated methods based on real-time PCR detection.

PubMed

Balachandran, Priya; Friberg, Maria; Vanlandingham, V; Kozak, K; Manolis, Amanda; Brevnov, Maxim; Crowley, Erin; Bird, Patrick; Goins, David; Furtado, Manohar R; Petrauskene, Olga V; Tebbs, Robert S; Charbonneau, Duane

2012-02-01

Reducing the risk of Salmonella contamination in pet food is critical for both companion animals and humans, and its importance is reflected by the substantial increase in the demand for pathogen testing. Accurate and rapid detection of foodborne pathogens improves food safety, protects the public health, and benefits food producers by assuring product quality while facilitating product release in a timely manner. Traditional culture-based methods for Salmonella screening are laborious and can take 5 to 7 days to obtain definitive results. In this study, we developed two methods for the detection of low levels of Salmonella in pet food using real-time PCR: (i) detection of Salmonella in 25 g of dried pet food in less than 14 h with an automated magnetic bead-based nucleic acid extraction method and (ii) detection of Salmonella in 375 g of composite dry pet food matrix in less than 24 h with a manual centrifugation-based nucleic acid preparation method. Both methods included a preclarification step using a novel protocol that removes food matrix-associated debris and PCR inhibitors and improves the sensitivity of detection. Validation studies revealed no significant differences between the two real-time PCR methods and the standard U.S. Food and Drug Administration Bacteriological Analytical Manual (chapter 5) culture confirmation method.

Prevalence of Salmonella in Australian reptiles.

PubMed

Scheelings, T Franciscus; Lightfoot, Dianne; Holz, Peter

2011-01-01

From January 2007 until June 2008, 504 reptiles of four families and 57 species were examined for Salmonella by using cloacal or intestinal swabs. Salmonella was identified in 139 (28%) of the 504 animals tested. Of the 504 reptiles examined, 210 were captive and 294 were wild. Ninety-eight (47%) of the captive reptiles were shedding Salmonella at the time of sampling. In contrast, only 41 (14%) of the wild reptiles were shedding Salmonella. The higher prevalence of Salmonella in captive reptiles was statistically significant (P<0.0001). No Salmonella was found in 60 wild, freshwater chelonians or 48 wild southern water skinks (Eulamprus heatwolei). Our results suggest that some species of wild reptiles in Australia are not natural carriers of Salmonella and that diet and captivity may influence Salmonella excretion in other species.

Detection of Salmonella spp. in veterinary samples by combining selective enrichment and real-time PCR.

PubMed

Goodman, Laura B; McDonough, Patrick L; Anderson, Renee R; Franklin-Guild, Rebecca J; Ryan, James R; Perkins, Gillian A; Thachil, Anil J; Glaser, Amy L; Thompson, Belinda S

2017-11-01

Rapid screening for enteric bacterial pathogens in clinical environments is essential for biosecurity. Salmonella found in veterinary hospitals, particularly Salmonella enterica serovar Dublin, can pose unique challenges for culture and testing because of its poor growth. Multiple Salmonella serovars including Dublin are emerging threats to public health given increasing prevalence and antimicrobial resistance. We adapted an automated food testing method to veterinary samples and evaluated the performance of the method in a variety of matrices including environmental samples ( n = 81), tissues ( n = 52), feces ( n = 148), and feed ( n = 29). A commercial kit was chosen as the basis for this approach in view of extensive performance characterizations published by multiple independent organizations. A workflow was established for efficiently and accurately testing veterinary matrices and environmental samples by use of real-time PCR after selective enrichment in Rappaport-Vassiliadis soya (RVS) medium. Using this method, the detection limit for S. Dublin improved by 100-fold over subculture on selective agars (eosin-methylene blue, brilliant green, and xylose-lysine-deoxycholate). Overall, the procedure was effective in detecting Salmonella spp. and provided next-day results.

Three-dimensional organotypic co-culture model of intestinal epithelial cells and macrophages to study Salmonella enterica colonization patterns.

PubMed

Barrila, Jennifer; Yang, Jiseon; Crabbé, Aurélie; Sarker, Shameema F; Liu, Yulong; Ott, C Mark; Nelman-Gonzalez, Mayra A; Clemett, Simon J; Nydam, Seth D; Forsyth, Rebecca J; Davis, Richard R; Crucian, Brian E; Quiriarte, Heather; Roland, Kenneth L; Brenneman, Karen; Sams, Clarence; Loscher, Christine; Nickerson, Cheryl A

2017-01-01

Three-dimensional models of human intestinal epithelium mimic the differentiated form and function of parental tissues often not exhibited by two-dimensional monolayers and respond to Salmonella in key ways that reflect in vivo infections. To further enhance the physiological relevance of three-dimensional models to more closely approximate in vivo intestinal microenvironments encountered by Salmonella , we developed and validated a novel three-dimensional co-culture infection model of colonic epithelial cells and macrophages using the NASA Rotating Wall Vessel bioreactor. First, U937 cells were activated upon collagen-coated scaffolds. HT-29 epithelial cells were then added and the three-dimensional model was cultured in the bioreactor until optimal differentiation was reached, as assessed by immunohistochemical profiling and bead uptake assays. The new co-culture model exhibited in vivo-like structural and phenotypic characteristics, including three-dimensional architecture, apical-basolateral polarity, well-formed tight/adherens junctions, mucin, multiple epithelial cell types, and functional macrophages. Phagocytic activity of macrophages was confirmed by uptake of inert, bacteria-sized beads. Contribution of macrophages to infection was assessed by colonization studies of Salmonella pathovars with different host adaptations and disease phenotypes (Typhimurium ST19 strain SL1344 and ST313 strain D23580; Typhi Ty2). In addition, Salmonella were cultured aerobically or microaerobically, recapitulating environments encountered prior to and during intestinal infection, respectively. All Salmonella strains exhibited decreased colonization in co-culture (HT-29-U937) relative to epithelial (HT-29) models, indicating antimicrobial function of macrophages. Interestingly, D23580 exhibited enhanced replication/survival in both models following invasion. Pathovar-specific differences in colonization and intracellular co-localization patterns were observed

A large outbreak of typhoid fever associated with a high rate of intestinal perforation in Kasese District, Uganda, 2008-2009.

PubMed

Neil, Karen P; Sodha, Samir V; Lukwago, Luswa; O-Tipo, Shikanga; Mikoleit, Matthew; Simington, Sherricka D; Mukobi, Peter; Balinandi, Stephen; Majalija, Samuel; Ayers, Joseph; Kagirita, Atek; Wefula, Edward; Asiimwe, Frank; Kweyamba, Vianney; Talkington, Deborah; Shieh, Wun-Ju; Adem, Patricia; Batten, Brigid C; Zaki, Sherif R; Mintz, Eric

2012-04-01

Salmonella enterica serovar Typhi (Salmonella Typhi) causes an estimated 22 million typhoid fever cases and 216 000 deaths annually worldwide. In Africa, the lack of laboratory diagnostic capacity limits the ability to recognize endemic typhoid fever and to detect outbreaks. We report a large laboratory-confirmed outbreak of typhoid fever in Uganda with a high proportion of intestinal perforations (IPs). A suspected case of typhoid fever was defined as fever and abdominal pain in a person with either vomiting, diarrhea, constipation, headache, weakness, arthralgia, poor response to antimalarial medications, or IP. From March 4, 2009 to April 17, 2009, specimens for blood and stool cultures and serology were collected from suspected cases. Antimicrobial susceptibility testing and pulsed-field gel electrophoresis (PFGE) were performed on Salmonella Typhi isolates. Surgical specimens from patients with IP were examined. A community survey was conducted to characterize the extent of the outbreak. From December 27, 2007 to July 30, 2009, 577 cases, 289 hospitalizations, 249 IPs, and 47 deaths from typhoid fever occurred; Salmonella Typhi was isolated from 27 (33%) of 81 patients. Isolates demonstrated multiple PFGE patterns and uniform susceptibility to ciprofloxacin. Surgical specimens from 30 patients were consistent with typhoid fever. Estimated typhoid fever incidence in the community survey was 8092 cases per 100 000 persons. This typhoid fever outbreak was detected because of an elevated number of IPs. Underreporting of milder illnesses and delayed and inadequate antimicrobial treatment contributed to the high perforation rate. Enhancing laboratory capacity for detection is critical to improving typhoid fever control.

Epidemiology and risk factors for endemic typhoid fever in Uzbekistan.

PubMed

Srikantiah, Padmini; Vafokulov, Sagdullo; Luby, Stephen P; Ishmail, Tharwat; Earhart, Kenneth; Khodjaev, Ne'mat; Jennings, Gregory; Crump, John A; Mahoney, Frank J

2007-07-01

To investigate the risk factors for infection with endemic typhoid fever in the Samarkand region of Uzbekistan. Case-control study of culture-confirmed bloodstream infection with Salmonella Typhi. Patients were compared to age-matched community controls. Salmonella Typhi isolates were tested for antimicrobial susceptibility. We enrolled 97 patients and 192 controls. The median age of patients was 19 years. In a conditional regression model, consumption of unboiled surface water outside the home [adjusted odds ratio (aOR)=3.0, 95% confidence interval (CI)=1.1-8.2], use of antimicrobials in the 2 weeks preceding onset of symptoms (aOR=12.2, 95% CI 4.0-37.0), and being a student (aOR=4.0, 95% CI 1.4-11.3) were independently associated with typhoid fever. Routinely washing vegetables (aOR 0.06, 95% CI 0.02-0.2) and dining at a tea-house (aOR 0.4, 95% CI 0.2-1.0) were associated with protection against illness. Salmonella Typhi resistant to ampicillin, chloramphenicol, and trimethoprim-sulfamethoxazole was identified in 6 (15%) of 41 isolates tested. Endemic typhoid fever in Uzbekistan is transmitted by contaminated water. Recent use of antimicrobials also increased risk of infection. Targeted efforts at improving drinking water quality, especially for students and young adults, are likely to decrease transmission of typhoid fever. Measures to decrease the unnecessary use of antimicrobials would be expected to reduce the risk of typhoid fever and decrease the spread of multiple drug-resistant Salmonella Typhi.

IroN, a Novel Outer Membrane Siderophore Receptor Characteristic of Salmonella enterica

PubMed Central

Bäumler, Andreas J.; Norris, Tracy L.; Lasco, Todd; Voigt, Wolfgang; Reissbrodt, Rolf; Rabsch, Wolfgang; Heffron, Fred

1998-01-01

Speciation in enterobacteria involved horizontal gene transfer. Therefore, analysis of genes acquired by horizontal transfer that are present in one species but not its close relatives is expected to give insights into how new bacterial species were formed. In this study we characterize iroN, a gene located downstream of the iroBC operon in the iroA locus of Salmonella enterica serotype Typhi. Like iroBC, the iroN gene is present in all phylogenetic lineages of S. enterica but is absent from closely related species such as Salmonella bongori or Escherichia coli. Comparison of the deduced amino acid sequence of iroN with other proteins suggested that this gene encodes an outer membrane siderophore receptor protein. Mutational analysis in S. enterica and expression in E. coli identified a 78-kDa outer membrane protein as the iroN gene product. When introduced into an E. coli fepA cir fiu aroB mutant on a cosmid, iroN mediated utilization of structurally related catecholate siderophores, including N-(2,3-dihydroxybenzoyl)-l-serine, myxochelin A, benzaldehyde-2,3-dihydroxybenzhydrazone, 2-N,6-N-bis(2,3-dihydroxybenzoyl)-l-lysine, 2-N,6-N-bis(2,3-dihydroxybenzoyl)-l-lysine amide, and enterochelin. These results suggest that the iroA locus functions in iron acquisition in S. enterica. PMID:9515912

Longevity of duodenal and peripheral T-cell and humoral responses to live-attenuated Salmonella Typhi strain Ty21a.

PubMed

Pennington, Shaun H; Ferreira, Daniela M; Reiné, Jesús; Nyirenda, Tonney S; Thompson, Ameeka L; Hancock, Carole A; Wright, Angela D; Gordon, Stephen B; Gordon, Melita A

2018-06-26

We have previously demonstrated that polyfunctional Ty21a-responsive CD4 + and CD8 + T cells are generated at the duodenal mucosa 18 days following vaccination with live-attenuated S. Typhi (Ty21a). The longevity of cellular responses has been assessed in peripheral blood, but persistence of duodenal responses is unknown. We vaccinated eight healthy adults with Ty21a. Peripheral blood and duodenal samples were acquired after a median of 1.5 years (ranging from 1.1 to 3.7 years) following vaccination. Cellular responses were assessed in peripheral blood and at the duodenal mucosa by flow cytometry. Levels of IgG and IgA were also assessed in peripheral blood by enzyme-linked immunosorbent assay. No T-cell responses were observed at the duodenal mucosa, but CD4 + T-cell responses to Ty21a and FliC were observed in peripheral blood. Peripheral anti-lipopolysaccharide IgG and IgA responses were also observed. Early immunoglobulin responses were not associated with the persistence of long-term cellular immune responses. Early T-cell responses which we have previously observed at the duodenal mucosa 18 days following oral vaccination with Ty21a could not be detected at a median of 1.5 years. Peripheral responses were observed at this time. Immunoglobulin responses observed shortly after vaccination were not associated with cellular immune responses at 1.5 years, suggesting that the persistence of cellular immunity is not associated with the strength of the initial humoral response to vaccination. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

HOLDING TIME STUDY FOR FECALS/SALMONELLA & CONNECTING LANGUAGE FOR 503 REGULATIONS

EPA Science Inventory

Current federal regulations required monitoring for fecal coliforms or Salmonella in biosolids destined for land application. Methods used for analysis of fecal coliforms and Salmonella have been developed and are currently in use for quantification of these organisms. Recently c...

O:2-CRM(197) conjugates against Salmonella Paratyphi A.

PubMed

Micoli, Francesca; Rondini, Simona; Gavini, Massimiliano; Lanzilao, Luisa; Medaglini, Donata; Saul, Allan; Martin, Laura B

2012-01-01

Enteric fevers remain a common and serious disease, affecting mainly children and adolescents in developing countries. Salmonella enterica serovar Typhi was believed to cause most enteric fever episodes, but several recent reports have shown an increasing incidence of S. Paratyphi A, encouraging the development of a bivalent vaccine to protect against both serovars, especially considering that at present there is no vaccine against S. Paratyphi A. The O-specific polysaccharide (O:2) of S. Paratyphi A is a protective antigen and clinical data have previously demonstrated the potential of using O:2 conjugate vaccines. Here we describe a new conjugation chemistry to link O:2 and the carrier protein CRM(197), using the terminus 3-deoxy-D-manno-octulosonic acid (KDO), thus leaving the O:2 chain unmodified. The new conjugates were tested in mice and compared with other O:2-antigen conjugates, synthesized adopting previously described methods that use CRM(197) as carrier protein. The newly developed conjugation chemistry yielded immunogenic conjugates with strong serum bactericidal activity against S. Paratyphi A.

Real-time PCR method combined with immunomagnetic separation for detecting healthy and heat-injured Salmonella Typhimurium on raw duck wings.

PubMed

Zheng, Qianwang; Mikš-Krajnik, Marta; Yang, Yishan; Xu, Wang; Yuk, Hyun-Gyun

2014-09-01

Conventional culture detection methods are time consuming and labor-intensive. For this reason, an alternative rapid method combining real-time PCR and immunomagnetic separation (IMS) was investigated in this study to detect both healthy and heat-injured Salmonella Typhimurium on raw duck wings. Firstly, the IMS method was optimized by determining the capture efficiency of Dynabeads(®) on Salmonella cells on raw duck wings with different bead incubation (10, 30 and 60 min) and magnetic separation (3, 10 and 30 min) times. Secondly, three Taqman primer sets, Sal, invA and ttr, were evaluated to optimize the real-time PCR protocol by comparing five parameters: inclusivity, exclusivity, PCR efficiency, detection probability and limit of detection (LOD). Thirdly, the optimized real-time PCR, in combination with IMS (PCR-IMS) assay, was compared with a standard ISO and a real-time PCR (PCR) method by analyzing artificially inoculated raw duck wings with healthy and heat-injured Salmonella cells at 10(1) and 10(0) CFU/25 g. Finally, the optimized PCR-IMS assay was validated for Salmonella detection in naturally contaminated raw duck wing samples. Under optimal IMS conditions (30 min bead incubation and 3 min magnetic separation times), approximately 85 and 64% of S. Typhimurium cells were captured by Dynabeads® from pure culture and inoculated raw duck wings, respectively. Although Sal and ttr primers exhibited 100% inclusivity and exclusivity for 16 Salmonella spp. and 36 non-Salmonella strains, the Sal primer showed lower LOD (10(3) CFU/ml) and higher PCR efficiency (94.1%) than the invA and ttr primers. Moreover, for Sal and invA primers, 100% detection probability on raw duck wings suspension was observed at 10(3) and 10(4) CFU/ml with and without IMS, respectively. Thus, the Sal primer was chosen for further experiments. The optimized PCR-IMS method was significantly (P=0.0011) better at detecting healthy Salmonella cells after 7-h enrichment than traditional PCR

Meta-analysis of chicken--salmonella infection experiments.

PubMed

Te Pas, Marinus F W; Hulsegge, Ina; Schokker, Dirkjan; Smits, Mari A; Fife, Mark; Zoorob, Rima; Endale, Marie-Laure; Rebel, Johanna M J

2012-04-24

Chicken meat and eggs can be a source of human zoonotic pathogens, especially Salmonella species. These food items contain a potential hazard for humans. Chickens lines differ in susceptibility for Salmonella and can harbor Salmonella pathogens without showing clinical signs of illness. Many investigations including genomic studies have examined the mechanisms how chickens react to infection. Apart from the innate immune response, many physiological mechanisms and pathways are reported to be involved in the chicken host response to Salmonella infection. The objective of this study was to perform a meta-analysis of diverse experiments to identify general and host specific mechanisms to the Salmonella challenge. Diverse chicken lines differing in susceptibility to Salmonella infection were challenged with different Salmonella serovars at several time points. Various tissues were sampled at different time points post-infection, and resulting host transcriptional differences investigated using different microarray platforms. The meta-analysis was performed with the R-package metaMA to create lists of differentially regulated genes. These gene lists showed many similarities for different chicken breeds and tissues, and also for different Salmonella serovars measured at different times post infection. Functional biological analysis of these differentially expressed gene lists revealed several common mechanisms for the chicken host response to Salmonella infection. The meta-analysis-specific genes (i.e. genes found differentially expressed only in the meta-analysis) confirmed and expanded the biological functional mechanisms. The meta-analysis combination of heterogeneous expression profiling data provided useful insights into the common metabolic pathways and functions of different chicken lines infected with different Salmonella serovars.

Survival of Salmonella Newport in oysters.

PubMed

Morrison, Christopher M; Armstrong, Alexandra E; Evans, Sanford; Mild, Rita M; Langdon, Christopher J; Joens, Lynn A

2011-08-02

Salmonella enterica is the leading cause of laboratory-confirmed foodborne illness in the United States and raw shellfish consumption is a commonly implicated source of gastrointestinal pathogens. A 2005 epidemiological study done in our laboratory by Brands et al., showed that oysters in the United States are contaminated with Salmonella, and in particular, a specific strain of the Newport serovar. This work sought to further investigate the host-microbe interactions between Salmonella Newport and oysters. A procedure was developed to reliably and repeatedly expose oysters to enteric bacteria and quantify the subsequent levels of bacterial survival. The results show that 10 days after an exposure to Salmonella Newport, an average concentration of 3.7 × 10(3)CFU/g remains within the oyster meat, and even after 60 days there still can be more than 10(2)CFU/g remaining. However, the strain of Newport that predominated in the market survey done by Brands et al. does not survive within oysters or the estuarine environment better than any other strains of Salmonella we tested. Using this same methodology, we compared Salmonella Newport's ability to survive within oysters to a non-pathogenic strain of E. coli and found that after 10 days the concentration of Salmonella was 200-times greater than that of E. coli. We also compared those same strains of Salmonella and E. coli in a depuration process to determine if a constant 120 L/h flux of clean seawater could significantly reduce the concentration of bacteria within oysters and found that after 3 days the oysters retained over 10(4)CFU/g of Salmonella while the oysters exposed to the non-pathogenic strain of E. coli contained 100-times less bacteria. Overall, the results of this study demonstrate that any of the clinically relevant serovars of Salmonella can survive within oysters for significant periods of time after just one exposure event. Based on the drastic differences in survivability between Salmonella and a non

Visualization of extracellular matrix components within sectioned Salmonella biofilms on the surface of human gallstones.

PubMed

Marshall, Joanna M; Flechtner, Alan D; La Perle, Krista M; Gunn, John S

2014-01-01

Chronic carriage of Salmonella Typhi is mediated primarily through the formation of bacterial biofilms on the surface of cholesterol gallstones. Biofilms, by definition, involve the formation of a bacterial community encased within a protective macromolecular matrix. Previous work has demonstrated the composition of the biofilm matrix to be complex and highly variable in response to altered environmental conditions. Although known to play an important role in bacterial persistence in a variety of contexts, the Salmonella biofilm matrix remains largely uncharacterized under physiological conditions. Initial attempts to study matrix components and architecture of the biofilm matrix on gallstone surfaces were hindered by the auto-fluorescence of cholesterol. In this work we describe a method for sectioning and direct visualization of extracellular matrix components of the Salmonella biofilm on the surface of human cholesterol gallstones and provide a description of the major matrix components observed therein. Confocal micrographs revealed robust biofilm formation, characterized by abundant but highly heterogeneous expression of polysaccharides such as LPS, Vi and O-antigen capsule. CsgA was not observed in the biofilm matrix and flagellar expression was tightly restricted to the biofilm-cholesterol interface. Images also revealed the presence of preexisting Enterobacteriaceae encased within the structure of the gallstone. These results demonstrate the use and feasibility of this method while highlighting the importance of studying the native architecture of the gallstone biofilm. A better understanding of the contribution of individual matrix components to the overall biofilm structure will facilitate the development of more effective and specific methods to disrupt these bacterial communities.

Risk reduction assessment of waterborne Salmonella and Vibrio by a chlorine contact disinfectant point-of-use device.

PubMed

Coulliette, Angela D; Enger, Kyle S; Weir, Mark H; Rose, Joan B

2013-06-01

Unsafe drinking water continues to burden developing countries despite improvements in clean water delivery and sanitation, in response to Millennium Development Goal 7. Salmonella serotype Typhi and Vibrio cholerae bacteria can contaminate drinking water, causing waterborne typhoid fever and cholera, respectively. Household water treatment (HWT) systems are widely promoted to consumers in developing countries but it is difficult to establish their benefits to the population for specific disease reduction. This research uses a laboratory assessment of halogenated chlorine beads treating contaminated water to inform a quantitative microbial risk assessment (QMRA) of S. Typhi and V. cholerae disease in a developing country community of 1000 people. Laboratory challenges using seeded well water resulted in log10 reductions of 5.44 (± 0.98 standard error (SE)) and 6.07 (± 0.09 SE) for Salmonella serotype Typhimurium and V. cholerae, respectively. In well water with 10% sewage and seeded bacteria, the log10 reductions were 6.06 (± 0.62 SE) and 7.78 (± 0.11 SE) for S. Typhimurium and V. cholerae, respectively. When one infected individual was contributing to the water contamination through fecal material leaking into the water source, the risk of disease associated with drinking untreated water was high according to a Monte Carlo analysis: a median of 0.20 (interquartile range [IQR] 0.017-0.54) for typhoid fever and a median of 0.11 (IQR 0.039-0.20) for cholera. If water was treated, risk greatly decreased, to a median of 4.1 × 10(-7) (IQR 1.6 × 10(-8) to 1.1 × 10(-5)) for typhoid fever and a median of 3.5 × 10(-9) (IQR 8.0 × 10(-10) to 1.3 × 10(-8)) for cholera. Insights on risk management policies and strategies for public health workers were gained using a simple QMRA scenario informed by laboratory assessment of HWT. Copyright © 2012 Elsevier GmbH. All rights reserved.

[Comparative studies of methods of salmonella enrichment (author's transl)].

PubMed

Pietzsch, O; Kretschmer, F J; Bulling, E

1975-07-01

Eight different methods of salmonella enrichment were compared in two series of experiments involving 100 samples of whole-egg powder and 80 samples of frozen whole liquid egg, respectively. 66 out of a total of 100 samples of whole-egg powder had been artificially infected with varying numbers of S. typhi-murium; 60 out of 80 samples of frozen whole liquid egg were found to be naturally infected with various salmonella species. 3 of the 8 methods (Table 1) were compared within an international collaborative study with 14 laboratories in 11 countries participating. A reduction of the pre-enrichment period from 18 to 6 hours and of volumes used in pre-enrichment and selective enrichment from 10 and 100 ml, respectively to 1 and 10 ml, respectively were found to have adverse influence upon the result of isolations, in particular in the case of weakly infected samples. In contrast, extended incubation over 48 hours as well as preparation of two sub-cultures on solid selective media following incubation of enrichment cultures over 18-24 hours and 42-48 hours, respectively always resulted in a certain increase of salmonella yield which, however, exhibited gradual differences for the individual methods examined. Preparation of a 2nd sub-culture meant, in particular, a decisive improvement of the result of isolations from artificially infected samples if selenite-cystine enrichment volumes were 10 and 100 ml, respectively. The best results could be obtained by means of the following methods of enrichment: Pre-enrichment of material in buffered peptone water at 37 degrees C over 18 hours; pipetting of 10 ml inoculated and incubated pre-enriched material into 100 ml selenite-cystine or tetrathionate enrichment medium according to MULLER-KAUFFMANN; onward incubation of the enrichment culture at 43 degrees C over 48 hours; and preparation of sub-cultures on solid selective media after 24 and 48 hours. The method using tetrathionate enrichment medium was found to be most

Comparison of Real-Time PCR, Reverse Transcriptase Real-Time PCR, Loop-Mediated Isothermal Amplification, and the FDA Conventional Microbiological Method for the Detection of Salmonella spp. in Produce ▿ †

PubMed Central

Zhang, Guodong; Brown, Eric W.; González-Escalona, Narjol

2011-01-01

Contamination of foods, especially produce, with Salmonella spp. is a major concern for public health. Several methods are available for the detection of Salmonella in produce, but their relative efficiency for detecting Salmonella in commonly consumed vegetables, often associated with outbreaks of food poisoning, needs to be confirmed. In this study, the effectiveness of three molecular methods for detection of Salmonella in six produce matrices was evaluated and compared to the FDA microbiological detection method. Samples of cilantro (coriander leaves), lettuce, parsley, spinach, tomato, and jalapeno pepper were inoculated with Salmonella serovars at two different levels (105 and <101 CFU/25 g of produce). The inoculated produce was assayed by the FDA Salmonella culture method (Bacteriological Analytical Manual) and by three molecular methods: quantitative real-time PCR (qPCR), quantitative reverse transcriptase real-time PCR (RT-qPCR), and loop-mediated isothermal amplification (LAMP). Comparable results were obtained by these four methods, which all detected as little as 2 CFU of Salmonella cells/25 g of produce. All control samples (not inoculated) were negative by the four methods. RT-qPCR detects only live Salmonella cells, obviating the danger of false-positive results from nonviable cells. False negatives (inhibition of either qPCR or RT-qPCR) were avoided by the use of either a DNA or an RNA amplification internal control (IAC). Compared to the conventional culture method, the qPCR, RT-qPCR, and LAMP assays allowed faster and equally accurate detection of Salmonella spp. in six high-risk produce commodities. PMID:21803916

Rapid detection of Salmonella in food and feed by coupling loop-mediated isothermal amplification with bioluminescent assay in real-time.

PubMed

Yang, Qianru; Domesle, Kelly J; Wang, Fei; Ge, Beilei

2016-06-17

Salmonella is among the most significant pathogens causing food and feed safety concerns. This study examined the rapid detection of Salmonella in various types of food and feed samples by coupling loop-mediated isothermal amplification (LAMP) with a novel reporter, bioluminescent assay in real-time (BART). Performance of the LAMP-BART assay was compared to a conventional LAMP and the commercially available 3M Molecular Detection Assay (MDA) Salmonella. The LAMP-BART assay was 100 % specific among 178 strains (151 Salmonella and 27 non-Salmonella) tested. The detection limits were 36 cells per reaction in pure culture and 10(4) to 10(6) CFU per 25 g in spiked food and feed samples without enrichment, which were comparable to those of the conventional LAMP and 3M MDA Salmonella but 5-10 min faster. Ground turkey showed a strong inhibition on 3M MDA Salmonella, requiring at least 10(8) CFU per 25 g for detection. The correlation between Salmonella cell numbers and LAMP-BART signals was high (R (2) = 0.941-0.962), suggesting good quantification capability. After 24 h enrichment, all three assays accurately detected 1 to 3 CFU per 25 g of Salmonella among five types of food (cantaloupe, ground beef, ground turkey, shell eggs, and tomato) and three types of feed (cattle feed, chicken feed, and dry dog food) examined. However, 10(1) CFU per 25 g was required for cattle feed when tested by 3M MDA Salmonella. The Salmonella LAMP-BART assay was rapid, specific, sensitive, quantitative, and robust. Upon further validation, it may become a valuable tool for routine screening of Salmonella in various types of food and feed samples.

Rapid and Sensitive Detection of Shigella spp. and Salmonella spp. by Multiple Endonuclease Restriction Real-Time Loop-Mediated Isothermal Amplification Technique

PubMed Central

Wang, Yi; Wang, Yan; Luo, Lijuan; Liu, Dongxin; Luo, Xia; Xu, Yanmei; Hu, Shoukui; Niu, Lina; Xu, Jianguo; Ye, Changyun

2015-01-01

Shigella and Salmonella are frequently isolated from various food samples and can cause human gastroenteritis. Here, a novel multiple endonuclease restriction real-time loop-mediated isothermal amplification technology (MERT-LAMP) were successfully established and validated for simultaneous detection of Shigella strains and Salmonella strains in only a single reaction. Two sets of MERT-LAMP primers for 2 kinds of pathogens were designed from ipaH gene of Shigella spp. and invA gene of Salmonella spp., respectively. Under the constant condition at 63°C, the positive results were yielded in as short as 12 min with the genomic DNA extracted from the 19 Shigella strains and 14 Salmonella strains, and the target pathogens present in a sample could be simultaneously identified based on distinct fluorescence curves in real-time format. Accordingly, the multiplex detection assay significantly reduced effort, materials and reagents used, and amplification and differentiation were conducted at the same time, obviating the use of postdetection procedures. The analytical sensitivity of MERT-LAMP was found to be 62.5 and 125 fg DNA/reaction with genomic templates of Shigella strains and Salmonella strains, which was consist with normal LAMP assay, and at least 10- and 100-fold more sensitive than that of qPCR and conventional PCR approaches. The limit of detection of MERT-LAMP for Shigella strains and Salmonella strains detection in artificially contaminated milk samples was 5.8 and 6.4 CFU per vessel. In conclusion, the MERT-LAMP methodology described here demonstrated a potential and valuable means for simultaneous screening of Shigella and Salmonella in a wide variety of samples. PMID:26697000

Phenotypical resistance correlation networks for 10 non-typhoidal Salmonella subpopulations in an active antimicrobial surveillance programme.

PubMed

Love, W J; Zawack, K A; Booth, J G; Gröhn, Y T; Lanzas, C

2018-06-01

Antimicrobials play a critical role in treating cases of invasive non-typhoidal salmonellosis (iNTS) and other diseases, but efficacy is hindered by resistant pathogens. Selection for phenotypical resistance may occur via several mechanisms. The current study aims to identify correlations that would allow indirect selection of increased resistance to ceftriaxone, ciprofloxacin and azithromycin to improve antimicrobial stewardship. These are medically important antibiotics for treating iNTS, but these resistances persist in non-Typhi Salmonella serotypes even though they are not licensed for use in US food animals. A set of 2875 Salmonella enterica isolates collected from animal sources by the National Antimicrobial Resistance Monitoring System were stratified in to 10 subpopulations based on serotype and host species. Collateral resistances in each subpopulation were estimated as network models of minimum inhibitory concentration partial correlations. Ceftriaxone sensitivity was correlated with other β-lactam resistances, and less commonly resistances to tetracycline, trimethoprim-sulfamethoxazole or kanamycin. Azithromycin resistance was frequently correlated with chloramphenicol resistance. Indirect selection for ciprofloxacin resistance via collateral selection appears unlikely. Density of the ACSSuT subgraph resistance aligned well with the phenotypical frequency. The current study identifies several important resistances in iNTS serotypes and further research is needed to identify the causative genetic correlations.

Bilateral breast abscess: a rare complication of enteric fever.

PubMed

Singh, S; Pandya, Y; Rathod, J; Trivedi, S

2009-01-01

Breast abscess is usually caused by Staphylococcus aureus in pregnant or lactating females. Salmonella spp. is occasionally associated with abscess formation in various organs, but breast abscess is a very rare complication. In enteric fever dissemination to multiple organ systems following bacteraemia can lead to localized abscess. We report a case of bilateral breast abscess due to Salmonella Typhi in an unmarried 35-year-old female without any predisposing conditions. She presented with fever and painful swelling of both the breasts. S. typhi was isolated from both breasts. Such rare cause must be suspected in females without any evident predisposing factors for effective management.

Meta-analysis of Chicken – Salmonella infection experiments

PubMed Central

2012-01-01

Background Chicken meat and eggs can be a source of human zoonotic pathogens, especially Salmonella species. These food items contain a potential hazard for humans. Chickens lines differ in susceptibility for Salmonella and can harbor Salmonella pathogens without showing clinical signs of illness. Many investigations including genomic studies have examined the mechanisms how chickens react to infection. Apart from the innate immune response, many physiological mechanisms and pathways are reported to be involved in the chicken host response to Salmonella infection. The objective of this study was to perform a meta-analysis of diverse experiments to identify general and host specific mechanisms to the Salmonella challenge. Results Diverse chicken lines differing in susceptibility to Salmonella infection were challenged with different Salmonella serovars at several time points. Various tissues were sampled at different time points post-infection, and resulting host transcriptional differences investigated using different microarray platforms. The meta-analysis was performed with the R-package metaMA to create lists of differentially regulated genes. These gene lists showed many similarities for different chicken breeds and tissues, and also for different Salmonella serovars measured at different times post infection. Functional biological analysis of these differentially expressed gene lists revealed several common mechanisms for the chicken host response to Salmonella infection. The meta-analysis-specific genes (i.e. genes found differentially expressed only in the meta-analysis) confirmed and expanded the biological functional mechanisms. Conclusions The meta-analysis combination of heterogeneous expression profiling data provided useful insights into the common metabolic pathways and functions of different chicken lines infected with different Salmonella serovars. PMID:22531008

Rapid and specific detection of Salmonella in water samples using real-time PCR and High Resolution Melt (HRM) curve analysis.

PubMed

van Blerk, G N; Leibach, L; Mabunda, A; Chapman, A; Louw, D

2011-01-01

A real-time PCR assay combined with a pre-enrichment step for the specific and rapid detection of Salmonella in water samples is described. Following amplification of the invA gene target, High Resolution Melt (HRM) curve analysis was used to discriminate between products formed and to positively identify invA amplification. The real-time PCR assay was evaluated for specificity and sensitivity. The assay displayed 100% specificity for Salmonella and combined with a 16-18 h non-selective pre-enrichment step, the assay proved to be highly sensitive with a detection limit of 1.0 CFU/ml for surface water samples. The detection assay also demonstrated a high intra-run and inter-run repeatability with very little variation in invA amplicon melting temperature. When applied to water samples received routinely by the laboratory, the assay showed the presence of Salmonella in particularly surface water and treated effluent samples. Using the HRM based assay, the time required for Salmonella detection was drastically shortened to less than 24 h compared to several days when using standard culturing methods. This assay provides a useful tool for routine water quality monitoring as well as for quick screening during disease outbreaks.

Typhoid fever & vaccine development: a partially answered question.

PubMed

Marathe, Sandhya A; Lahiri, Amit; Negi, Vidya Devi; Chakravortty, Dipshikha

2012-01-01

Typhoid fever is a systemic disease caused by the human specific Gram-negative pathogen Salmonella enterica serovar Typhi (S. Typhi). The extra-intestinal infections caused by Salmonella are very fatal. The incidence of typhoid fever remains very high in impoverished areas and the emergence of multidrug resistance has made the situation worse. To combat and to reduce the morbidity and mortality caused by typhoid fever, many preventive measures and strategies have been employed, the most important being vaccination. In recent years, many Salmonella vaccines have been developed including live attenuated as well as DNA vaccines and their clinical trials have shown encouraging results. But with the increasing antibiotic resistance, the development of potent vaccine candidate for typhoid fever is a need of the hour. This review discusses the latest trends in the typhoid vaccine development and the clinical trials which are underway.

Salmonella Pathogenicity and Host Adaptation in Chicken-Associated Serovars

PubMed Central

Johnson, Timothy J.; Ricke, Steven C.; Nayak, Rajesh; Danzeisen, Jessica

2013-01-01

SUMMARY Enteric pathogens such as Salmonella enterica cause significant morbidity and mortality. S. enterica serovars are a diverse group of pathogens that have evolved to survive in a wide range of environments and across multiple hosts. S. enterica serovars such as S. Typhi, S. Dublin, and S. Gallinarum have a restricted host range, in which they are typically associated with one or a few host species, while S. Enteritidis and S. Typhimurium have broad host ranges. This review examines how S. enterica has evolved through adaptation to different host environments, especially as related to the chicken host, and continues to be an important human pathogen. Several factors impact host range, and these include the acquisition of genes via horizontal gene transfer with plasmids, transposons, and phages, which can potentially expand host range, and the loss of genes or their function, which would reduce the range of hosts that the organism can infect. S. Gallinarum, with a limited host range, has a large number of pseudogenes in its genome compared to broader-host-range serovars. S. enterica serovars such as S. Kentucky and S. Heidelberg also often have plasmids that may help them colonize poultry more efficiently. The ability to colonize different hosts also involves interactions with the host's immune system and commensal organisms that are present. Thus, the factors that impact the ability of Salmonella to colonize a particular host species, such as chickens, are complex and multifactorial, involving the host, the pathogen, and extrinsic pressures. It is the interplay of these factors which leads to the differences in host ranges that we observe today. PMID:24296573

Enhanced detection rate of typhoid fever among clinically suspected patients in a tertiary referral hospital in Dhaka, Bangladesh using nested polymerase chain reaction technology.

PubMed

Khan, S; Miah, M R; Khatun, S

2015-12-01

A nested polymerase chain reaction (PCR) specific for Salmonella enterica subspecies enteric serovar Typhi was used for the detection of the pathogen, in blood. This study was done during the period of March 2013 to February 2014. A total of 80 clinically suspected cases of typhoid fever were included in the study. Blood was collected from all participating individuals. Nested PCR targeting the flagellin gene (fliC) of Salmonella Typhi & blood culture were done for each of the cases. The positivity rate of PCR & blood culture was 70%& 20% respectively. The positivity rate of PCR was significantly higher than blood culture (P< 0.05). With the nested PCR, S. Typhi DNAs were detected from blood specimens of 67.2% (43/64) patients among the suspected typhoid fever cases on the basis of clinical features but with negative cultures. We conclude that the PCR technique could be used as a novel diagnostic method of typhoid fever, particularly in culture-negative cases in an endemic country like Bangladesh.

Bacteria and cancer: cause, coincidence or cure? A review

PubMed Central

Mager, DL

2006-01-01

Research has found that certain bacteria are associated with human cancers. Their role, however, is still unclear. Convincing evidence links some species to carcinogenesis while others appear promising in the diagnosis, prevention or treatment of cancers. The complex relationship between bacteria and humans is demonstrated by Helicobacter pylori and Salmonella typhi infections. Research has shown that H. pylori can cause gastric cancer or MALT lymphoma in some individuals. In contrast, exposure to H. pylori appears to reduce the risk of esophageal cancer in others. Salmonella typhi infection has been associated with the development of gallbladder cancer; however S. typhi is a promising carrier of therapeutic agents for melanoma, colon and bladder cancers. Thus bacterial species and their roles in particular cancers appear to differ among different individuals. Many species, however, share an important characteristic: highly site-specific colonization. This critical factor may lead to the development of non-invasive diagnostic tests, innovative treatments and cancer vaccines. PMID:16566840

Loop-Mediated Isothermal Amplification of the sefA Gene for Rapid Detection of Salmonella Enteritidis and Salmonella Gallinarum in Chickens.

PubMed

Gong, Jiansen; Zhuang, Linlin; Zhu, Chunhong; Shi, Shourong; Zhang, Di; Zhang, Linji; Yu, Yan; Dou, Xinhong; Xu, Bu; Wang, Chengming

2016-04-01

Salmonella spp. pose a threat to both human and animal health, with more than 2600 serovars having been reported to date. Salmonella serovars are usually identified by slide agglutination tests, which are labor intensive and time consuming. In an attempt to develop a more rapid screening method for the major poultry Salmonella serovars, we developed a loop-mediated isothermal amplification (LAMP) assay, which directly detected the sefA gene, a fimbrial operon gene existing in several specific serovars of Salmonella enterica including the major poultry serovars, namely Salmonella enterica serovar Enteritidis (Salmonella Enteritidis) and Salmonella enterica serovar Gallinarum (Salmonella Gallinarum). With the 177 bacterial strains we tested, positive reactions were only observed with 85 strains of serovar Salmonella Enteritidis and Salmonella Gallinarum. The detection limit of the LAMP assay was 4 CFU/reaction with genomic DNAs of Salmonella Enteritidis (ATCC 13076) from pure culture and 400 CFU/ reaction with DNA extracted from spiked chicken feces. The LAMP assay was more sensitive than conventional culture, especially without enrichment, in detecting Salmonella Enteritidis (CMCC 50041) in the spiked fecal samples. The results show the sefA LAMP method is a rapid, sensitive, specific, and practical method for directly detection of Salmonella Enteritidis and Salmonella Gallinarum in chickens. The sefA LAMP assay can potentially serve as new on-site diagnostics in the poultry industry.

Typhoid Fever in South Africa in an Endemic HIV Setting.

PubMed

Keddy, Karen H; Sooka, Arvinda; Smith, Anthony M; Musekiwa, Alfred; Tau, Nomsa P; Klugman, Keith P; Angulo, Frederick J

2016-01-01

Typhoid fever remains an important disease in Africa, associated with outbreaks and the emerging multidrug resistant Salmonella enterica serotype Typhi (Salmonella Typhi) haplotype, H58. This study describes the incidence of, and factors associated with mortality due to, typhoid fever in South Africa, where HIV prevalence is high. Nationwide active laboratory-based surveillance for culture-confirmed typhoid fever was undertaken from 2003-2013. At selected institutions, additional clinical data from patients were collected including age, sex, HIV status, disease severity and outcome. HIV prevalence among typhoid fever patients was compared to national HIV seroprevalence estimates. The national reference laboratory tested Salmonella Typhi isolates for antimicrobial susceptibility and haplotype. Unadjusted and adjusted logistic regression analyses were conducted determining factors associated with typhoid fever mortality. We identified 855 typhoid fever cases: annual incidence ranged from 0.11 to 0.39 per 100,000 population. Additional clinical data were available for 369 (46.8%) cases presenting to the selected sites. Among typhoid fever patients with known HIV status, 19.3% (29/150) were HIV-infected. In adult females, HIV prevalence in typhoid fever patients was 43.2% (19/44) versus 15.7% national HIV seroprevalence (P < .001); in adult males, 16.3% (7/43) versus 12.3% national HIV seroprevalence (P = .2). H58 represented 11.9% (22/185) of Salmonella Typhi isolates tested. Increased mortality was associated with HIV infection (AOR 10.7; 95% CI 2.3-50.3) and disease severity (AOR 9.8; 95% CI 1.6-60.0) on multivariate analysis. Typhoid fever incidence in South Africa was largely unchanged from 2003-2013. Typhoid fever mortality was associated disease severity. HIV infection may be a contributing factor. Interventions mandate improved health care access, including to HIV management programmes as well as patient education. Further studies are necessary to clarify

Evolutionary genetic relationships of clones of Salmonella serovars that cause human typhoid and other enteric fevers.

PubMed Central

Selander, R K; Beltran, P; Smith, N H; Helmuth, R; Rubin, F A; Kopecko, D J; Ferris, K; Tall, B D; Cravioto, A; Musser, J M

1990-01-01

Multilocus enzyme electrophoresis was employed to measure chromosomal genotypic diversity and evolutionary relationships among 761 isolates of the serovars Salmonella typhi, S. paratyphi A, S. paratyphi B, S. paratyphi C, and S. sendai, which are human-adapted agents of enteric fever, and S. miami and S. java, which are serotypically similar to S. sendai and S. paratyphi B, respectively, but cause gastroenteritis in both humans and animals. To determine the phylogenetic positions of the clones of these forms within the context of the salmonellae of subspecies I, comparative data for 22 other common serovars were utilized. Except for S. paratyphi A and S. sendai, the analysis revealed no close phylogenetic relationships among clones of different human-adapted serovars, which implies convergence in host adaptation and virulence factors. Clones of S. miami are not allied with those of S. sendai or S. paratyphi A, being, instead, closely related to strains of S. panama. Clones of S. paratyphi B and S. java belong to a large phylogenetic complex that includes clones of S. typhimurium, S. heidelberg, S. saintpaul, and S. muenchen. Most strains of S. paratyphi B belong to a globally distributed clone that is highly polymorphic in biotype, bacteriophage type, and several other characters, whereas strains of S. java represent seven diverse lineages. The flagellar monophasic forms of S. java are genotypically more similar to clones of S. typhimurium than to other clones of S. java or S. paratyphi B. Clones of S. paratyphi C are related to those of S. choleraesuis. DNA probing with a segment of the viaB region specific for the Vi capsular antigen genes indicated that the frequent failure of isolates of S. paratyphi C to express Vi antigen is almost entirely attributable to regulatory processes rather than to an absence of the structural determinant genes themselves. Two clones of S. typhisuis are related to those of S. choleraesuis and S. paratyphi C, but a third clone is not

Assessment of Salmonella survival in dry-cured Italian salami.

PubMed

Bonardi, S; Bruini, I; Bolzoni, L; Cozzolino, P; Pierantoni, M; Brindani, F; Bellotti, P; Renzi, M; Pongolini, S

2017-12-04

The inactivation of Salmonella during curing of Italian traditional pork salami was investigated. A total of 150 batches of ground raw meat (GRM) used for salami manufacturing by four producers were tested for Salmonella by real-time PCR followed by ISO 6579 cultural confirmation and MPN enumeration. Salami produced with Salmonella positive GRMs were re-tested at the end of their curing period. Aw, pH and NaCl content were also measured. Detection of Salmonella was performed testing both 25 and 50g of the samples. By Real-Time PCR 37% of the GRMs resulted positive, but cultural detection of Salmonella was obtained in 14% of the samples only. Salmonella enumeration ranged from 31 MPN/g to <1.3 MPN/g. The difference between testing 50g and 25g of the samples was statistically significant (p value≤0.01). In particular, ISO-50g detected Salmonella in 100% of all positive samples, vs. 62% of ISO-25g. Salami made of the contaminated GRMs were 29% Salmonella-positive, as most batches of salami produced with Salmonella-positive GRMs resulted negative after regular curing (20-48days). Overall, 13% of salami produced with Salmonella-contaminated GRMs were positive. They belonged to six batches, which turned out negative after prolonged curing ranging between 49 and 86days. Salmonella enumeration in salami ranged from 8.7 MPN/g to <1.3 MPN/g. Unlike GRMs, no significant difference was observed between the ISO-50g and the ISO-25g in detecting Salmonella in cured salami (p value: >0.05). The most common Salmonella serovars in GRMs were Derby (52%), Typhimurium monophasic variant 4, (Barbuti et al., 1993), 12:i:- (19%) and Stanley (10%). Salmonella Derby (56%), London, Branderup, Panama (13%, respectively) and Goldcoast (6%) were most frequent in cured salami. The study showed negative correlation between real-time CT values and cultural confirmation of Salmonella, as well as the importance of sample size for Salmonella detection. Among considered factors with possible effect

A sulfhydryl-rich IgM protein with multiple serological specificities.

PubMed Central

Merlini, G; Zettervall, O; Forsgren, A; Galliano, M; Lindberg, A A; Svenson, S B; Pavesi, F; Turesson, I

1987-01-01

A monoclonal IgM lambda protein from a patient (E.T.) suffering from a lymphocytic lymphoma agglutinated Salmonella typhi bacteria and uncoated acryl particles. The antigenic determinant on Salmonella typhi bacteria was found to be 0-12 (alpha-D-Galp-(1-2)-alpha-D-Manp) while the structure on acryl particles recognized by IgM ET has not been defined. Both binding sites for bacteria and acryl particle determinants are localized on the same IgM molecule. The uncommon affinity of this IgM protein for some divalent heavy metal ions led to the finding of an unusually high content of sulfhydryl groups in the Fab portion of the molecule. PMID:2443287

Autophagy Facilitates Salmonella Replication in HeLa Cells

PubMed Central

Yu, Hong B.; Croxen, Matthew A.; Marchiando, Amanda M.; Ferreira, Rosana B. R.; Cadwell, Ken; Foster, Leonard J.; Finlay, B. Brett

2014-01-01

ABSTRACT Autophagy is a process whereby a double-membrane structure (autophagosome) engulfs unnecessary cytosolic proteins, organelles, and invading pathogens and delivers them to the lysosome for degradation. We examined the fate of cytosolic Salmonella targeted by autophagy and found that autophagy-targeted Salmonella present in the cytosol of HeLa cells correlates with intracellular bacterial replication. Real-time analyses revealed that a subset of cytosolic Salmonella extensively associates with autophagy components p62 and/or LC3 and replicates quickly, whereas intravacuolar Salmonella shows no or very limited association with p62 or LC3 and replicates much more slowly. Replication of cytosolic Salmonella in HeLa cells is significantly decreased when autophagy components are depleted. Eventually, hyperreplication of cytosolic Salmonella potentiates cell detachment, facilitating the dissemination of Salmonella to neighboring cells. We propose that Salmonella benefits from autophagy for its cytosolic replication in HeLa cells. PMID:24618251

Serum bactericidal assay for the evaluation of typhoid vaccine using a semi-automated colony-counting method.

PubMed

Jang, Mi Seon; Sahastrabuddhe, Sushant; Yun, Cheol-Heui; Han, Seung Hyun; Yang, Jae Seung

2016-08-01

Typhoid fever, mainly caused by Salmonella enterica serovar Typhi (S. Typhi), is a life-threatening disease, mostly in developing countries. Enzyme-linked immunosorbent assay (ELISA) is widely used to quantify antibodies against S. Typhi in serum but does not provide information about functional antibody titers. Although the serum bactericidal assay (SBA) using an agar plate is often used to measure functional antibody titers against various bacterial pathogens in clinical specimens, it has rarely been used for typhoid vaccines because it is time-consuming and labor-intensive. In the present study, we established an improved SBA against S. Typhi using a semi-automated colony-counting system with a square agar plate harboring 24 samples. The semi-automated SBA efficiently measured bactericidal titers of sera from individuals immunized with S. Typhi Vi polysaccharide vaccines. The assay specifically responded to S. Typhi Ty2 but not to other irrelevant enteric bacteria including Vibrio cholerae and Shigella flexneri. Baby rabbit complement was more appropriate source for the SBA against S. Typhi than complements from adult rabbit, guinea pig, and human. We also examined the correlation between SBA and ELISA for measuring antibody responses against S. Typhi using pre- and post-vaccination sera from 18 human volunteers. The SBA titer showed a good correlation with anti-Vi IgG quantity in the serum as determined by Spearman correlation coefficient of 0.737 (P < 0.001). Taken together, the semi-automated SBA might be efficient, accurate, sensitive, and specific enough to measure functional antibody titers against S. Typhi in sera from human subjects immunized with typhoid vaccines. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Stable Chromosomal Expression of Shigella flexneri 2a and 3a O-Antigens in the Live Salmonella Oral Vaccine Vector Ty21a

PubMed Central

Osorio, Manuel; Takeda, Kazuyo; Stibitz, Scott; Kopecko, Dennis J.

2017-01-01

ABSTRACT We have been exploring the use of the live attenuated Salmonella enterica serovar Typhi Ty21a vaccine strain as a versatile oral vaccine vector for the expression and delivery of multiple foreign antigens, including Shigella O-antigens. In this study, we separately cloned genes necessary for the biosynthesis of the Shigella flexneri serotype 2a and 3a O-antigens, which have been shown to provide broad cross-protection to multiple disease-predominant S. flexneri serotypes. The cloned S. flexneri 2a rfb operon, along with bgt and gtrII, contained on the SfII bacteriophage, was sufficient in Ty21a to express the heterologous S. flexneri 2a O-antigen containing the 3,4 antigenic determinants. Further, this rfb operon, along with gtrA, gtrB, and gtrX contained on the Sfx bacteriophage and oac contained on the Sf6 bacteriophage, was sufficient to express S. flexneri 3a O-antigen containing the 6, 7, and 8 antigenic determinants. Ty21a, with these plasmid-carried or chromosomally inserted genes, demonstrated simultaneous and stable expression of homologous S. Typhi O-antigen plus the heterologous S. flexneri O-antigen. Candidate Ty21a vaccine strains expressing heterologous S. flexneri 2a or 3a lipopolysaccharide (LPS) elicited significant serum antibody responses against both homologous S. Typhi and heterologous Shigella LPS and protected mice against virulent S. flexneri 2a or 3a challenges. These new S. flexneri 2a and 3a O-antigen-expressing Ty21a vaccine strains, together with our previously constructed Ty21a strains expressing Shigella sonnei or Shigella dysenteriae 1 O-antigens, have the potential to be used together for simultaneous protection against the predominant causes of shigellosis worldwide as well as against typhoid fever. PMID:29046309

PREVALENCE AND CHARACTERISTICS OF ESCHERICHIA COLI AND SALMONELLA SPP. IN THE FECES OF WILD URBAN NORWAY AND BLACK RATS (RATTUS NORVEGICUS AND RATTUS RATTUS) FROM AN INNER-CITY NEIGHBORHOOD OF VANCOUVER, CANADA.

PubMed

Himsworth, Chelsea G; Zabek, Erin; Desruisseau, Andrea; Parmley, E Jane; Reid-Smith, Richard; Jardine, Claire M; Tang, Patrick; Patrick, David M

2015-07-01

Although rat feces are widely suspected to be a source of pathogenic bacteria, few investigators have studied fecal pathogens in rats. We investigated the prevalence and characteristics of Escherichia coli and Salmonella spp. in Norway and black rats (Rattus norvegicus and Rattus rattus, respectively) from an urban neighborhood of Vancouver, Canada, collected September 2011-August 2012. Colon content was cultured for E. coli and Salmonella spp. and screened for the seven most-common enteropathogenic Shiga toxin-producing E. coli (STEC) serotypes by PCR. Isolates were tested for antimicrobial resistance and Salmonella isolates were serotyped. We detected E. coli in 397/633 (62.7%) urban rats. Forty-one of 397 (6.5%) E. coli isolates were resistant to ≥ 1 antimicrobial while 17 (4.3%) were multidrug resistant (including two isolates demonstrating extended-spectrum β-lactamase resistance). Ten of 633 (1.6%) urban rats were carrying STEC serotypes including O145, O103, O26, and O45. Norway rats were more likely to be carrying E. coli compared to black rats, and there was geographic clustering of specific resistance patterns and STEC serotypes. Salmonella spp. were detected in 3/633 (0.5%) rats including serotypes Derby, Indiana, and Enteritidis. In contrast to zoonotic pathogens for which rats are the natural reservoir (e.g., Leptospira interrogans, Rickettsia typhi, Seoul virus), rats likely acquired E. coli and Salmonella spp. from their environment. The ability of rats to be a 'sponge' for environmental pathogens has received little consideration, and the ecology and public health significance of these organisms in rats requires further investigation.

A novel strategy to obtain quantitative data for modelling: combined enrichment and real-time PCR for enumeration of salmonellae from pig carcasses.

PubMed

Krämer, Nadine; Löfström, Charlotta; Vigre, Håkan; Hoorfar, Jeffrey; Bunge, Cornelia; Malorny, Burkhard

2011-03-01

Salmonella is a major zoonotic pathogen which causes outbreaks and sporadic cases of gastroenteritis in humans worldwide. The primary sources for Salmonella are food-producing animals such as pigs and poultry. For risk assessment and hazard analysis and critical control point (HACCP) concepts, it is essential to produce large amounts of quantitative data, which is currently not achievable with the standard cultural based methods for enumeration of Salmonella. This study presents the development of a novel strategy to enumerate low numbers of Salmonella in cork borer samples taken from pig carcasses as a first concept and proof of principle for a new sensitive and rapid quantification method based on combined enrichment and real-time PCR. The novelty of the approach is in the short pre-enrichment step, where for most bacteria, growth is in the log phase. The method consists of an 8h pre-enrichment of the cork borer sample diluted 1:10 in non-selective buffered peptone water, followed by DNA extraction, and Salmonella detection and quantification by real-time PCR. The limit of quantification was 1.4 colony forming units (CFU)/20 cm(2) (approximately 10 g) of artificially contaminated sample with 95% confidence interval of ± 0.7 log CFU/sample. The precision was similar to the standard reference most probable number (MPN) method. A screening of 200 potentially naturally contaminated cork borer samples obtained over seven weeks in a slaughterhouse resulted in 25 Salmonella-positive samples. The analysis of salmonellae within these samples showed that the PCR method had a higher sensitivity for samples with a low contamination level (<6.7 CFU/sample), where 15 of the samples negative with the MPN method was detected with the PCR method and 5 were found to be negative by both methods. For the samples with a higher contamination level (6.7-310 CFU/sample) a good agreement between the results obtained with the PCR and MPN methods was obtained. The quantitative real-time

Salmonella induces prominent gene expression in the rat colon

PubMed Central

Rodenburg, Wendy; Keijer, Jaap; Kramer, Evelien; Roosing, Susanne; Vink, Carolien; Katan, Martijn B; van der Meer, Roelof; Bovee-Oudenhoven, Ingeborg MJ

2007-01-01

Background Salmonella enteritidis is suggested to translocate in the small intestine. In vivo it induces gene expression changes in the ileal mucosa and Peyer's patches. Stimulation of Salmonella translocation by dietary prebiotics fermented in colon suggests involvement of the colon as well. However, effects of Salmonella on colonic gene expression in vivo are largely unknown. We aimed to characterize time dependent Salmonella-induced changes of colonic mucosal gene expression in rats using whole genome microarrays. For this, rats were orally infected with Salmonella enteritidis to mimic a foodborne infection and colonic gene expression was determined at days 1, 3 and 6 post-infection (n = 8 rats per time-point). As fructo-oligosaccharides (FOS) affect colonic physiology, we analyzed colonic mucosal gene expression of FOS-fed versus cellulose-fed rats infected with Salmonella in a separate experiment. Colonic mucosal samples were isolated at day 2 post-infection. Results Salmonella affected transport (e.g. Chloride channel calcium activated 6, H+/K+ transporting Atp-ase), antimicrobial defense (e.g. Lipopolysaccharide binding protein, Defensin 5 and phospholipase A2), inflammation (e.g. calprotectin), oxidative stress related genes (e.g. Dual oxidase 2 and Glutathione peroxidase 2) and Proteolysis (e.g. Ubiquitin D and Proteosome subunit beta type 9). Furthermore, Salmonella translocation increased serum IFNγ and many interferon-related genes in colonic mucosa. The gene most strongly induced by Salmonella infection was Pancreatitis Associated Protein (Pap), showing >100-fold induction at day 6 after oral infection. Results were confirmed by Q-PCR in individual rats. Stimulation of Salmonella translocation by dietary FOS was accompanied by enhancement of the Salmonella-induced mucosal processes, not by induction of other processes. Conclusion We conclude that the colon is a target tissue for Salmonella, considering the abundant changes in mucosal gene expression

Salmonella induces prominent gene expression in the rat colon.

PubMed

Rodenburg, Wendy; Keijer, Jaap; Kramer, Evelien; Roosing, Susanne; Vink, Carolien; Katan, Martijn B; van der Meer, Roelof; Bovee-Oudenhoven, Ingeborg M J

2007-09-12

Salmonella enteritidis is suggested to translocate in the small intestine. In vivo it induces gene expression changes in the ileal mucosa and Peyer's patches. Stimulation of Salmonella translocation by dietary prebiotics fermented in colon suggests involvement of the colon as well. However, effects of Salmonella on colonic gene expression in vivo are largely unknown. We aimed to characterize time dependent Salmonella-induced changes of colonic mucosal gene expression in rats using whole genome microarrays. For this, rats were orally infected with Salmonella enteritidis to mimic a foodborne infection and colonic gene expression was determined at days 1, 3 and 6 post-infection (n = 8 rats per time-point). As fructo-oligosaccharides (FOS) affect colonic physiology, we analyzed colonic mucosal gene expression of FOS-fed versus cellulose-fed rats infected with Salmonella in a separate experiment. Colonic mucosal samples were isolated at day 2 post-infection. Salmonella affected transport (e.g. Chloride channel calcium activated 6, H+/K+ transporting Atp-ase), antimicrobial defense (e.g. Lipopolysaccharide binding protein, Defensin 5 and phospholipase A2), inflammation (e.g. calprotectin), oxidative stress related genes (e.g. Dual oxidase 2 and Glutathione peroxidase 2) and Proteolysis (e.g. Ubiquitin D and Proteosome subunit beta type 9). Furthermore, Salmonella translocation increased serum IFN gamma and many interferon-related genes in colonic mucosa. The gene most strongly induced by Salmonella infection was Pancreatitis Associated Protein (Pap), showing >100-fold induction at day 6 after oral infection. Results were confirmed by Q-PCR in individual rats. Stimulation of Salmonella translocation by dietary FOS was accompanied by enhancement of the Salmonella-induced mucosal processes, not by induction of other processes. We conclude that the colon is a target tissue for Salmonella, considering the abundant changes in mucosal gene expression.

Novel genomic tools for specific and real-time detection of biothreat and frequently encountered foodborne pathogens.

PubMed

Woubit, Abdela; Yehualaeshet, Teshome; Habtemariam, Tsegaye; Samuel, Temesgen

2012-04-01

The bacterial genera Escherichia, Salmonella, Shigella, Vibrio, Yersinia, and Francisella include important food safety and biothreat agents. By extensive mining of the whole genome and protein databases of diverse, closely and distantly related bacterial species and strains, we have identified novel genome regions, which we utilized to develop a rapid detection platform for these pathogens. The specific genomic targets we have identified to design the primers in Francisella tularensis subsp. tularensis, F. tularensis subsp. novicida, Shigella dysenteriae, Salmonella enterica serovar Typhimurium, Vibrio cholerae, Yersinia pestis, and Yersinia pseudotuberculosis contained either known genes or putative proteins. Primer sets were designed from the target regions for use in real-time PCR assays to detect specific biothreat pathogens at species or strain levels. The primer sets were first tested by in silico PCR against whole-genome sequences of different species, subspecies, or strains and then by in vitro PCR against genomic DNA preparations from 23 strains representing six biothreat agents (Escherichia coli O157:H7 strain EDL 933, Shigella dysenteriae, S. enterica serovar Typhi, F. tularensis subsp. tularensis, V. cholerae, and Y. pestis) and six foodborne pathogens (Salmonella Typhimurium, Salmonella Saintpaul, Shigella sonnei, F. tularensis subsp. novicida, Vibrio parahaemolyticus, and Y. pseudotuberculosis). Each pathogen was specifically identifiable at the genus and species levels. Sensitivity assays performed with purified DNA showed the lowest detection limit of 128 fg of DNA/μl for F. tularensis subsp. tularensis. A preliminary test to detect Shigella organisms in a milk matrix also enabled the detection of 6 to 60 CFU/ml. These new tools could ultimately be used to develop platforms to simultaneously detect these pathogens.

What Have We Learned From the Typhoid Fever Surveillance in Africa Program?

PubMed

Baker, Stephen; Hombach, Joachim; Marks, Florian

2016-03-15

The Typhoid Fever Surveillance in Africa Program (TSAP) was established in 2009 to fill the data void concerning invasive Salmonella disease in sub-Saharan Africa, and to specifically estimate the burden of bloodstream infections caused by the key pathogen, Salmonella enterica serovar Typhi. TSAP has achieved this ambitious target, finding high incidences of typhoid fever in both rural and urban populations in several countries in sub-Saharan Africa. The results of TSAP will undoubtedly dictate the direction of future typhoid fever research in Africa, and at last provides a key piece of the disease burden jigsaw puzzle. With the dawn of new Vi conjugate vaccines against Salmonella Typhi, the next priority for the typhoid community must be providing the required data on these vaccines so they can be licensed and provided to those in high-risk groups and locations across sub-Saharan Africa. © The Author 2016. Published by Oxford University Press for the Infectious Diseases Society of America.

[Salmonella].

PubMed

Amo, Kiyoko

2012-08-01

Nontyphoidal salmonella causes infectious gastroenteritis, and sometimes causes bacteremia and meningitis. Gastroenteritis associated with nontyphoidal salmonella, in which fever, diarrhea, vomiting and abdominal cramps, is a common disease. The major way of transmittion is food of animal origin, for example egg. That is the reason why precausion is so important such as wash hands before cooking, avoid eating raw egg and wash the cooking utensils after contact raw foods. In this report, I presented the rare severe case of encephalitis caused by salmonella infection.

β-Lactam Resistance and Enterobacteriaceae, United States

PubMed Central

Joyce, Kevin; Fey, Paul D.; Nelson, Jennifer M.; Angulo, Frederick J.; Barrett, Timothy J.

2005-01-01

Extended-spectrum cephalosporins (ESC) are an important drug class for treating severe Salmonella infections. We screened the human collection from the National Antimicrobial Resistance Monitoring System 2000 for ESC resistance mechanisms. Of non-Typhi Salmonella tested, 3.2% (44/1,378) contained blaCMY genes. Novel findings included blaCMY-positive Escherichia coli O157:H7 and a blaSHV-positive Salmonella isolate. CMY-positive isolates showed a ceftriaxone MIC >2 µg/mL. PMID:16229784

Beta-lactam resistance and Enterobacteriaceae, United States.

PubMed

Whichard, Jean M; Joyce, Kevin; Fey, Paul D; Nelson, Jennifer M; Angulo, Frederick J; Barrett, Timothy J

2005-09-01

Extended-spectrum cephalosporins (ESC) are an important drug class for treating severe Salmonella infections. We screened the human collection from the National Antimicrobial Resistance Monitoring System 2000 for ESC resistance mechanisms. Of non-Typhi Salmonella tested, 3.2% (44/1,378) contained blaCMY genes. Novel findings included blaCMY-positive Escherichia coli O157:H7 and a blaSHV-positive Salmonella isolate. CMY-positive isolates showed a ceftriaxone MIC > or =2 microg/mL.

Effects of Climate Change on Salmonella Infections

PubMed Central

Akil, Luma; Reddy, Remata S.

2014-01-01

Abstract Background: Climate change and global warming have been reported to increase spread of foodborne pathogens. To understand these effects on Salmonella infections, modeling approaches such as regression analysis and neural network (NN) were used. Methods: Monthly data for Salmonella outbreaks in Mississippi (MS), Tennessee (TN), and Alabama (AL) were analyzed from 2002 to 2011 using analysis of variance and time series analysis. Meteorological data were collected and the correlation with salmonellosis was examined using regression analysis and NN. Results: A seasonal trend in Salmonella infections was observed (p<0.001). Strong positive correlation was found between high temperature and Salmonella infections in MS and for the combined states (MS, TN, AL) models (R2=0.554; R2=0.415, respectively). NN models showed a strong effect of rise in temperature on the Salmonella outbreaks. In this study, an increase of 1°F was shown to result in four cases increase of Salmonella in MS. However, no correlation between monthly average precipitation rate and Salmonella infections was observed. Conclusion: There is consistent evidence that gastrointestinal infection with bacterial pathogens is positively correlated with ambient temperature, as warmer temperatures enable more rapid replication. Warming trends in the United States and specifically in the southern states may increase rates of Salmonella infections. PMID:25496072

Effects of climate change on Salmonella infections.

PubMed

Akil, Luma; Ahmad, H Anwar; Reddy, Remata S

2014-12-01

Climate change and global warming have been reported to increase spread of foodborne pathogens. To understand these effects on Salmonella infections, modeling approaches such as regression analysis and neural network (NN) were used. Monthly data for Salmonella outbreaks in Mississippi (MS), Tennessee (TN), and Alabama (AL) were analyzed from 2002 to 2011 using analysis of variance and time series analysis. Meteorological data were collected and the correlation with salmonellosis was examined using regression analysis and NN. A seasonal trend in Salmonella infections was observed (p<0.001). Strong positive correlation was found between high temperature and Salmonella infections in MS and for the combined states (MS, TN, AL) models (R(2)=0.554; R(2)=0.415, respectively). NN models showed a strong effect of rise in temperature on the Salmonella outbreaks. In this study, an increase of 1°F was shown to result in four cases increase of Salmonella in MS. However, no correlation between monthly average precipitation rate and Salmonella infections was observed. There is consistent evidence that gastrointestinal infection with bacterial pathogens is positively correlated with ambient temperature, as warmer temperatures enable more rapid replication. Warming trends in the United States and specifically in the southern states may increase rates of Salmonella infections.

The Gathering Storm: Is Untreatable Typhoid Fever on the Way?

PubMed Central

Simon, Raphael

2018-01-01

ABSTRACT Klemm et al. (mBio 9:e00105-18, 2018, https://doi.org/10.1128/mBio.00105-18) present comprehensive antibiotic sensitivity patterns and genomic sequence data on Salmonella enterica serovar Typhi blood culture isolates from typhoid fever cases during an epidemic in Pakistan. Microbiologic and genomic data pinpoint the identities and locations of the antimicrobial resistance genes and the outbreak strain’s lineage. They propose that Salmonella enterica serovar Typhi be added to the list of bacterial pathogens of public health importance that have become extensively drug resistant (XDR). This paper portends possible dire scenarios for typhoid fever control if XDR strains disseminate globally. Since the outbreak strain is of the H58 haplotype, known for its ability to spread worldwide and displace endemic S. Typhi, this concern is well-founded. The report of Klemm et al. forewarns the global community to address control of typhoid fever more aggressively through prevention, should therapeutic options disappear. This Commentary frames the Klemm et al. findings within a historic perspective. PMID:29559573

Reduction of Salmonella in ground chicken using a bacteriophage.

PubMed

Grant, Ar'Quette; Parveen, Salina; Schwarz, Jurgen; Hashem, Fawzy; Vimini, Bob

2017-08-01

This study's goal was to ascertain the effectiveness of a commercially available Salmonella bacteriophage during ground chicken production focusing on: water source, different Salmonella serovars, and time. Salmonella-free boneless, skinless chicken meat was inoculated with 4.0 Log CFU/cm2 of either a cocktail of 3 Salmonella isolates derived from ground chicken (GC) or a cocktail of 3 Salmonella strains not isolated from ground chicken (non-GC). Bacteriophages were spread onto the chicken using sterile tap or filtered water for 30 min or 8 h. Salmonella was recovered using standard plating method. Greater Salmonella reduction was observed when the bacteriophage was diluted in sterile tap water than in sterile filtered water: 0.39 Log CFU/cm2 and 0.23 Log CFU/cm2 reduction after 30 min, respectively (P < 0.05). The non-GC isolates showed reductions of 0.71 Log CFU/cm2 and 0.90 Log CFU/cm2 after 30 min and 8 h, respectively (P < 0.05). The GC isolates were less sensitive to the bacteriophage: 0.39 Log CFU/cm2 and 0.67 Log CFU/cm2 reductions after 30 min and 8 h, respectively (P < 0.05). In conclusion, bacteriophage reduction was dependent on water used to dilute the bacteriophage, Salmonella's susceptibility to the bacteriophage, and treatment time. © 2017 Poultry Science Association Inc.

MicroSEQ® Salmonella spp. Detection Kit Using the Pathatrix® 10-Pooling Salmonella spp. Kit Linked Protocol Method Modification.

PubMed

Wall, Jason; Conrad, Rick; Latham, Kathy; Liu, Eric

2014-03-01

Real-time PCR methods for detecting foodborne pathogens offer the advantages of simplicity and quick time to results compared to traditional culture methods. The addition of a recirculating pooled immunomagnetic separation method prior to real-time PCR analysis increases processing output while reducing both cost and labor. This AOAC Research Institute method modification study validates the MicroSEQ® Salmonella spp. Detection Kit [AOAC Performance Tested Method (PTM) 031001] linked with the Pathatrix® 10-Pooling Salmonella spp. Kit (AOAC PTM 090203C) in diced tomatoes, chocolate, and deli ham. The Pathatrix 10-Pooling protocol represents a method modification of the enrichment portion of the MicroSEQ Salmonella spp. The results of the method modification were compared to standard cultural reference methods for diced tomatoes, chocolate, and deli ham. All three matrixes were analyzed in a paired study design. An additional set of chocolate test portions was analyzed using an alternative enrichment medium in an unpaired study design. For all matrixes tested, there were no statistically significant differences in the number of positive test portions detected by the modified candidate method compared to the appropriate reference method. The MicroSEQ Salmonella spp. protocol linked with the Pathatrix individual or 10-Pooling procedure demonstrated reliability as a rapid, simplified, method for the preparation of samples and subsequent detection of Salmonella in diced tomatoes, chocolate, and deli ham.

Prevalence of Salmonella spp. in pet turtles and their environment

PubMed Central

Back, Du-San; Shin, Gee-Wook; Wendt, Mitchell

2016-01-01

Pet turtles are known as a source of Salmonella infection to humans when handled in captivity. Thirty four turtles purchased from pet shops and online markets in Korea were examined to determine whether the turtles and their environment were contaminated with Salmonella spp. Salmonella spp. were isolated from fecal samples of 17 turtles. These isolates were identified as S. enterica through 16S rRNA gene sequencing. The isolation rate of Salmonella spp. from the soil and water samples increased over time. We concluded that a high percentage of turtles being sold in pet shops were infected with Salmonella spp., and their environments tend to become contaminated over time unless they are maintained properly. These results indicate that pet turtles could be a potential risk of salmonellosis in Korea. PMID:27729933

Difference in cellular damage and cell death in thermal death time disks and high hydrostatic pressure treated Salmonella Enteritidis (ATCC13076) in liquid whole egg

USDA-ARS?s Scientific Manuscript database

Differences in membrane damage including leakage of intracellular UV-materials and loss of viability of Salmonella Enteritidis (ATCC13076) in liquid whole egg (LWE) following thermal-death-time (TDT) disk and high hydrostatic pressure treatments were examined. Salmonella enteritidis was inoculated ...

Low-oxygen tensions found in Salmonella-infected gut tissue boost Salmonella replication in macrophages by impairing antimicrobial activity and augmenting Salmonella virulence.

PubMed

Jennewein, Jonas; Matuszak, Jasmin; Walter, Steffi; Felmy, Boas; Gendera, Kathrin; Schatz, Valentin; Nowottny, Monika; Liebsch, Gregor; Hensel, Michael; Hardt, Wolf-Dietrich; Gerlach, Roman G; Jantsch, Jonathan

2015-12-01

In Salmonella infection, the Salmonella pathogenicity island-2 (SPI-2)-encoded type three secretion system (T3SS2) is of key importance for systemic disease and survival in host cells. For instance, in the streptomycin-pretreated mouse model SPI-2-dependent Salmonella replication in lamina propria CD11c(-)CXCR1(-) monocytic phagocytes/macrophages (MΦ) is required for the development of colitis. In addition, containment of intracellular Salmonella in the gut critically depends on the antimicrobial effects of the phagocyte NADPH oxidase (PHOX), and possibly type 2 nitric oxide synthase (NOS2). For both antimicrobial enzyme complexes, oxygen is an essential substrate. However, the amount of available oxygen upon enteroinvasive Salmonella infection in the gut tissue and its impact on Salmonella-MΦ interactions was unknown. Therefore, we measured the gut tissue oxygen levels in a model of Salmonella enterocolitis using luminescence two-dimensional in vivo oxygen imaging. We found that gut tissue oxygen levels dropped from ∼78 Torr (∼11% O2) to values of ∼16 Torr (∼2% O2) during infection. Because in vivo virulence of Salmonella depends on the Salmonella survival in MΦ, Salmonella-MΦ interaction was analysed under such low oxygen values. These experiments revealed an increased intracellular replication and survival of wild-type and t3ss2 non-expressing Salmonella. These findings were paralleled by blunted nitric oxide and reactive oxygen species (ROS) production and reduced Salmonella ROS perception. In addition, hypoxia enhanced SPI-2 transcription and translocation of SPI-2-encoded virulence protein. Neither pharmacological blockade of PHOX and NOS2 nor impairment of T3SS2 virulence function alone mimicked the effect of hypoxia on Salmonella replication under normoxic conditions. However, if t3ss2 non-expressing Salmonella were used, hypoxia did not further enhance Salmonella recovery in a PHOX and NOS2-deficient situation. Hence, these data suggest that

Chemical closet treatment of typhoid carrier faeces.

PubMed

Harvey, R W; Price, T H

1972-09-01

An investigation to test the efficiency of chemical closets in treating excreta from typhoid carriers is described. The use of these closets kept a stream, which had in the past frequently contained Salmonella typhi, typhoid free for 24 months. Selenite broth as made in this laboratory, containing a final concentration of 0.8% sodium hydrogen selenite when inoculated with the water sample, was significantly better than commercial selenite brilliant green enrichment broth for the recovery of S. typhi.

Typhoid Fever in South Africa in an Endemic HIV Setting

PubMed Central

Keddy, Karen H.; Sooka, Arvinda; Smith, Anthony M.; Musekiwa, Alfred; Tau, Nomsa P.; Klugman, Keith P.; Angulo, Frederick J.

2016-01-01

Background Typhoid fever remains an important disease in Africa, associated with outbreaks and the emerging multidrug resistant Salmonella enterica serotype Typhi (Salmonella Typhi) haplotype, H58. This study describes the incidence of, and factors associated with mortality due to, typhoid fever in South Africa, where HIV prevalence is high. Methods and Findings Nationwide active laboratory-based surveillance for culture-confirmed typhoid fever was undertaken from 2003–2013. At selected institutions, additional clinical data from patients were collected including age, sex, HIV status, disease severity and outcome. HIV prevalence among typhoid fever patients was compared to national HIV seroprevalence estimates. The national reference laboratory tested Salmonella Typhi isolates for antimicrobial susceptibility and haplotype. Unadjusted and adjusted logistic regression analyses were conducted determining factors associated with typhoid fever mortality. We identified 855 typhoid fever cases: annual incidence ranged from 0.11 to 0.39 per 100,000 population. Additional clinical data were available for 369 (46.8%) cases presenting to the selected sites. Among typhoid fever patients with known HIV status, 19.3% (29/150) were HIV-infected. In adult females, HIV prevalence in typhoid fever patients was 43.2% (19/44) versus 15.7% national HIV seroprevalence (P < .001); in adult males, 16.3% (7/43) versus 12.3% national HIV seroprevalence (P = .2). H58 represented 11.9% (22/185) of Salmonella Typhi isolates tested. Increased mortality was associated with HIV infection (AOR 10.7; 95% CI 2.3–50.3) and disease severity (AOR 9.8; 95% CI 1.6–60.0) on multivariate analysis. Conclusions Typhoid fever incidence in South Africa was largely unchanged from 2003–2013. Typhoid fever mortality was associated disease severity. HIV infection may be a contributing factor. Interventions mandate improved health care access, including to HIV management programmes as well as patient

Cellular damage of Escherichia coli 0157:H7 and Salmonella spp. in apple juice treated with high hydrostatic pressure and thermal death time disks

USDA-ARS?s Scientific Manuscript database

Differences in membrane damage including leakage of intracellular UV-materials and loss of viability of Salmonella spp. and Escherichia coli O157:H7 bacteria in apple juice, pH 3.1 following thermal-death-time (TDT) disk and high hydrostatic pressure (HHP) treatments were investigated. Salmonella an...

Effects of postharvest handling conditions on internalization and growth of Salmonella enterica in tomatoes.

PubMed

Zhou, Bin; Luo, Yaguang; Nou, Xiangwu; Yang, Yang; Wu, Yunpeng; Wang, Qin

2014-03-01

Salmonella internalization in tomatoes during postharvest handling is a major food safety concern. This study was conducted to determine the effect of immersion time, immersion depth, and temperature differential between bacterial suspension and tomato pulp on the internalization of Salmonella enterica in tomato fruits. The effect of storage temperature and duration on the survival and growth of internalized Salmonella cells was also evaluated. Overall, immersion time significantly affected the incidence and extent of S. enterica internalization (P < 0.0001), with a linear correlation between immersion time and Salmonella internalization. The depth of Salmonella internalization in tomato tissues also increased with increasing immersion time. Immersion time also significantly influenced the degree to which the temperature differential affected Salmonella internalization. With an immersion time of 2 min, the temperature differential had no significant effect on Salmonella internalization (P = 0.2536). However, with an immersion time of 15 min, a significantly larger Salmonella population became internalized in tomatoes immersed in solutions with a -30°F (-16.7°C) temperature differential. Internalized S. enterica cells persisted in the core tissues during 14 days of storage. Strain type and storage duration significantly affected (P < 0.05) both the frequency detected and the population of internalized Salmonella recovered, but storage temperatures of 55 to 70°F (12.8 to 21.1°C) did not (P > 0.05). These findings indicate the importance of preventing pathogen internalization during postharvest handling.

A magneto-DNA nanoparticle system for the rapid and sensitive diagnosis of enteric fever

PubMed Central

Park, Ki Soo; Chung, Hyun Jung; Khanam, Farhana; Lee, Hakho; Rashu, Rasheduzzaman; Bhuiyan, Md. Taufiqur; Berger, Amanda; Harris, Jason B.; Calderwood, Stephen B.; Ryan, Edward T.; Qadri, Firdausi; Weissleder, Ralph; Charles, Richelle C.

2016-01-01

There is currently no widely available optimal assay for diagnosing patients with enteric fever. Here we present a novel assay designed to detect amplified Salmonella nucleic acid (mRNA) using magneto-DNA probes and a miniaturized nuclear magnetic resonance device. We designed primers for genes specific to S. Typhi, S. Paratyphi A, and genes conserved among Salmonella enterica spp. and utilized strongly magnetized nanoparticles to enhance the detection signal. Blood samples spiked with in vitro grown S. Typhi, S. Paratyphi A, S. Typhimurium, and E. coli were used to confirm the specificity of each probe-set, and serial 10-fold dilutions were used to determine the limit of the detection of the assay, 0.01–1.0 CFU/ml. For proof of principle, we applied our assay to 0.5 mL blood samples from 5 patients with culture-confirmed enteric fever from Bangladesh in comparison to 3 healthy controls. We were able to detect amplified target cDNA in all 5 cases of enteric fever; no detectable signal was seen in the healthy controls. Our results suggest that a magneto-DNA nanoparticle system, with an assay time from blood collection of 3.5 hours, may be a promising platform for the rapid and culture-free diagnosis of enteric fever and non-typhoidal Salmonella bacteremia. PMID:27605393

Applications of immunomagnetic capture and time-resolved fluorescence to detect outbreak Escherichia coli O157 and Salmonella in alfalfa sprouts

NASA Astrophysics Data System (ADS)

Tu, Shu-I.; Gordon, Marsha; Fett, William F.; Gehring, Andrew G.; Irwin, Peter L.

2004-03-01

Commercially available alfalfa seeds were inoculated with low levels (~ 4 CFU/g) of pathogenic bacteria. The inoculated seeds were then allowed to sprout in sterile tap water at 22°C. After 48 hours, the irrigation water and sprouts were separately transferred to bovine heart infusion (BHI) media. The microbes in the BHI samples were allowed to grow for 4 hours at 37°C and 160 rpm. Specific immunomagnetic beads (IMB) were then applied to capture the E.coli O157 and/or Salmonella in the growth media. Separation and concentration of IMB-captured pathogens were achieved using magnetic separators. The captured E. coli O157:H7 and Salmonella spp were further tagged with europium (Eu) labeled anti-E. coli O157 antibodies and samarium (Sm) labeled anti-Salmonella antibodies, respectively. After washing, the lanthanide labels were extracted out from the complexes by specific chelators to form strongly fluorescent chelates. The specific time-resolved fluorescence (TRF) associated with Eu or Sm was measured to estimate the extent of capture of the E. coli O157 and Salmonella, respectively. The results indicated that the approach could detect E. coli O157 and Salmonella enterica from the seeds inoculated with ~ 4 CFU/g of the pathogens. Non-targeted bacteria, e.g., Aeromonas and Citrobacter exhibited essentially no cross reactivity. Since the pathogen detection from the sprouts was achieved within 6 hours, the developed methodology could be use as a rapid, sensitive and specific screening process for E. coli O157 and Salmonella enterica in this popular salad food.

Salmonella species isolated from animal feed in Iraq.

PubMed Central

Al-Hindawi, N; Taha, R R

1979-01-01

Of 700 animal feed samples, 32 (4.5%) harbored Salmonella. The highest percentage of contamination was found in sheep feed and local protein. A total of 17 Salmonella serotypes were identified. The most frequent serotypes were Salmonella meleagridis. S. bornum, S. montevideo, and S. drypool. S. bornum was isolated for the first time in Iraq and from both local feed and its ingredients. The common somatic group found was that of Salmonella group C; then came groups E, G, B, and D. Three serotypes (S. enteritidis, S. california, and S. muenchen) seemed to form a link of infection among feed, food, patients, and carriers. PMID:453836

Human Salmonella and Concurrent Decreased Susceptibility to Quinolones and Extended-Spectrum Cephalosporins

PubMed Central

Gay, Kathryn; Stevenson, Jennifer E.; Joyce, Kevin J.; Cooper, Kara L.; Omondi, Michael; Medalla, Felicita; Jacoby, George A.; Barrett, Timothy J.

2007-01-01

The National Antimicrobial Resistance Monitoring System monitors susceptibility among Enterobacteriaceae in humans in the United States. We studied isolates exhibiting decreased susceptibility to quinolones (nalidixic acid MIC >32 µg/mL or ciprofloxacin MIC >0.12 µg/mL) and extended-spectrum cephalosporins (ceftiofur or ceftriaxone MIC >2 µg/mL) during 1996–2004. Of non-Typhi Salmonella, 0.19% (27/14,043) met these criteria: 11 Senftenberg; 6 Typhimurium; 3 Newport; 2 Enteridis; and 1 each Agona, Haifa, Mbandaka, Saintpaul, and Uganda. Twenty-six isolates had gyrA mutations (11 at codon 83 only, 3 at codon 87 only, 12 at both). All Senftenberg isolates had parC mutations (S80I and T57S); 6 others had the T57S mutation. The Mbandaka isolate contained qnrB2. Eight isolates contained blaCMY-2; 1 Senftenberg contained blaCMY-23. One Senftenberg and 1Typhimurium isolate contained blaSHV-12; the Mbandaka isolate contained blaSHV-30. Nine Senftenberg isolates contained blaOXA-1; 1 contained blaOXA-9. Further studies should address patient outcomes, risk factors, and resistance dissemination prevention strategies. PMID:18217551

Human Salmonella and concurrent decreased susceptibility to quinolones and extended-spectrum cephalosporins.

PubMed

Whichard, Jean M; Gay, Kathryn; Stevenson, Jennifer E; Joyce, Kevin J; Cooper, Kara L; Omondi, Michael; Medalla, Felicita; Jacoby, George A; Barrett, Timothy J

2007-11-01

The National Antimicrobial Resistance Monitoring System monitors susceptibility among Enterobacteriaceae in humans in the United States. We studied isolates exhibiting decreased susceptibility to quinolones (nalidixic acid MIC >32 microg/mL or ciprofloxacin MIC > or =0.12 microg/mL) and extended-spectrum cephalosporins (ceftiofur or ceftriaxone MIC > or =2 microg/mL) during 1996-2004. Of non-Typhi Salmonella, 0.19% (27/14,043) met these criteria: 11 Senftenberg; 6 Typhimurium; 3 Newport; 2 Enteridis; and 1 each Agona, Haifa, Mbandaka, Saintpaul, and Uganda. Twenty-six isolates had gyrA mutations (11 at codon 83 only, 3 at codon 87 only, 12 at both). All Senftenberg isolates had parC mutations (S801 and T57S); 6 others had the T57S mutation. The Mbandaka isolate contained qnrB2. Eight isolates contained bla(CMY-2); 1 Senftenberg contained bla(CMY-23). One Senftenberg and 1 Typhimurium isolate contained bla(SHV-12); the Mbandaka isolate contained bla(SHV-30). Nine Senftenberg isolates contained bla(OXA-1) contained bla(OXA-9). Further studies should address patient outcomes, risk factors, and resistance dissemination prevention strategies.

Molecular and cellular characterization of a Salmonella enterica serovar Paratyphi a outbreak strain and the human immune response to infection.

PubMed

Gal-Mor, Ohad; Suez, Jotham; Elhadad, Dana; Porwollik, Steffen; Leshem, Eyal; Valinsky, Lea; McClelland, Michael; Schwartz, Eliezer; Rahav, Galia

2012-02-01

Enteric fever is an invasive life-threatening systemic disease caused by the Salmonella enterica human-adapted serovars Typhi and Paratyphi. Increasing incidence of infections with Salmonella enterica serovar Paratyphi A and the spreading of its antibiotic-resistant derivates pose a significant health concern in some areas of the world. Herein, we describe a molecular and phenotypic characterization of an S. Paratyphi A strain accounted for a recent paratyphoid outbreak in Nepal that affected at least 37 travelers. Pulsed-field gel electrophoresis analysis of the outbreak isolates revealed one genetic clone (pulsotype), confirming a single infecting source. Genetic profiling of the outbreak strain demonstrated the contribution of specific bacteriophages as a prime source of genetic diversity among clinical isolates of S. Paratyphi A. Phenotypic characterization in comparison with the S. Paratyphi A ATCC 9150 reference sequenced strain showed differences in flagellar morphology and increased abilities of the outbreak strain with respect to its motility, invasion into nonphagocytic cells, intracellular multiplication, survival within macrophages, and higher induction of interleukin-8 (IL-8) secreted by host cells. Collectively, these differences suggest an enhanced virulence potential of this strain and demonstrate an interesting phenotypic variation among S. Paratyphi A isolates. In vivo profiling of 16 inflammatory cytokines in patients infected with the outbreak strain revealed a common profile of a remarkable gamma interferon (IFN-γ) induction together with elevated concentrations of tumor necrosis factor alpha (TNF-α), IL-6, IL-8, IL-10, and IL-15, but not IL-12, which was previously demonstrated as elevated in nontyphoidal Salmonella infections. This apparent profile implies a distinct immune response to paratyphoid infections.

A multiplex real-time PCR assay, based on invA and pagC genes, for the detection and quantification of Salmonella enterica from cattle lymph nodes.

PubMed

Bai, Jianfa; Trinetta, Valentina; Shi, Xiaorong; Noll, Lance W; Magossi, Gabriela; Zheng, Wanglong; Porter, Elizabeth P; Cernicchiaro, Natalia; Renter, David G; Nagaraja, Tiruvoor G

2018-05-01

Cattle lymph nodes can harbor Salmonella and potentially contaminate beef products. We have developed and validated a new real-time PCR (qPCR) assay for the detection and quantification of Salmonella enterica in cattle lymph nodes. The assay targets both the invA and pagC genes, the most conserved molecular targets in Salmonella enterica. An 18S rRNA gene assay that amplifies from cattle and other animal species was also included as an internal control. Available DNA sequences for invA, pagC and 18S rRNA genes were used for primer and probe selections. Three Salmonella serotypes, S. Typhimurium, S. Anatum, and S. Montevideo, were used to assess the assay's analytical sensitivity. Correlation coefficients of standard curves generated for each target and for all three serotypes were >99% and qPCR amplification efficiencies were between 93% and 110%. Assay sensitivity was also determined using standard curve data generated from Salmonella-negative cattle lymph nodes spiked with 10-fold dilutions of the three Salmonella serotypes. Assay specificity was determined using Salmonella culture method, and qPCR testing on 36 Salmonella strains representing 33 serotypes, 38 Salmonella strains of unknown serotypes, 252 E. coli strains representing 40 serogroups, and 31 other bacterial strains representing 18 different species. A collection of 647 cattle lymph node samples from steers procured from the Midwest region of the US were tested by the qPCR, and compared to culture-method of detection. Salmonella prevalence by qPCR for pre-enriched and enriched lymph nodes was 19.8% (128/647) and 94.9% (614/647), respectively. A majority of qPCR positive pre-enriched samples (105/128) were at concentrations between 10 4 and 10 5  CFU/mL. Culture method detected Salmonella in 7.7% (50/647) and 80.7% (522/647) of pre- and post-enriched samples, respectively; 96.0% (48/50) of pre-enriched and 99.4% (519/522) of post-enriched culture-positive samples were also positive by qPCR. More

Effect of Exposure Time and Organic Matter on Efficacy of Antimicrobial Compounds against Shiga Toxin-Producing Escherichia coli and Salmonella.

PubMed

Kalchayanand, Norasak; Koohmaraie, Mohammad; Wheeler, Tommy L

2016-04-01

Several antimicrobial compounds are in commercial meat processing plants for pathogen control on beef carcasses. However, the efficacy of the method used is influenced by a number of factors, such as spray pressure, temperature, type of chemical and concentration, exposure time, method of application, equipment design, and the stage in the process that the method is applied. The objective of this study was to evaluate effectiveness of time of exposure of various antimicrobial compounds against nine strains of Shiga toxin-producing Escherichia coli (STEC) and four strains of Salmonella in aqueous antimicrobial solutions with and without organic matter. Non-O157 STEC, STEC O157:H7, and Salmonella were exposed to the following aqueous antimicrobial solutions with or without beef purge for 15, 30, 60, 120, 300, 600, and 1,800 s: (i) 2.5% lactic acid, (ii) 4.0% lactic acid, (iii) 2.5% Beefxide, (iv) 1% Aftec 3000, (v) 200 ppm of peracetic acid, (vi) 300 ppm of hypobromous acid, and (vii) water as a control. In general, increasing exposure time to antimicrobial compounds significantly (P ≤ 0.05) increased the effectiveness against pathogens tested. In aqueous antimicrobial solutions without organic matter, both peracetic acid and hypobromous acid were the most effective in inactivating populations of STEC and Salmonella, providing at least 5.0-log reductions with exposure for 15 s. However, in antimicrobials containing organic matter, 4.0% lactic acid was the most effective compound in reducing levels of STEC and Salmonella, providing 2- to 3-log reductions with exposure for 15 s. The results of this study indicated that organic matter and exposure time influenced the efficacy of antimicrobial compounds against pathogens, especially with oxidizer compounds. These factors should be considered when choosing an antimicrobial compound for an intervention.

Novel Structure and Function of Typhoid Toxin

MedlinePlus

... the reasons why Salmonella typhi , the cause of typhoid fever, is so dangerous. The findings could help guide ... A few people, known as carriers, recover from typhoid fever but continue to carry the bacteria. Perhaps the ...

Microbiological Detection Systems for Molecular Analysis of Environmental Water and Soil Samples

EPA Science Inventory

Multiple detection systems are being targeted to track various species and genotypes of pathogens found in environmental samples with the overreaching goal of developing analytical separation and detection techniques for Salmonella enterica Serovars Typhi, Cryptosporidium parvum,...

Salmonella Levels Associated with Skin of Turkey Parts.

PubMed

Peng, Ye; Deng, Xiang Y; Harrison, Mark A; Alali, Walid Q

2016-05-01

Turkey skin is used as a source of fat in finished ground turkey products. Salmonella-contaminated skin may potentially disseminate this pathogen to ground turkey. The objective of this study was to determine and compare Salmonella levels (presence and numbers) associated with the skin of turkey parts (i.e., drumstick, thigh, and wing). Over a 10-month period, 20 turkey flocks expected to be highly contaminated with Salmonella based on boot-sock testing data of turkey houses were sampled. A total of 300 samples per type of turkey part were collected postchill and were tested for Salmonella using the most-probable-number (MPN) and enrichment methods. Overall, Salmonella was detected in 13.7, 19.7, and 25.0% of drumstick skin, thigh skin, and wing skin samples, respectively. Salmonella prevalence from wing skin was significantly higher (P < 0.05) than in drumstick skin, but the difference was not significant (P > 0.05) when compared with thigh skin. Salmonella was 2.4 times more likely to be present from thigh skin (odds ratio = 2.4; P < 0.05) when the pathogen was found from wing skin. Salmonella mean numbers from drumstick, thigh, and wing were 1.18, 1.29, and 1.45 log MPN per sample, respectively; these values were not significantly different (P > 0.05). Based on our findings, the high prevalence of Salmonella associated with the skin of turkey parts could be a potential source for ground turkey contamination.

MALDI-TOF mass spectrometry provides high accuracy in identification of Salmonella at species level but is limited to type or subtype Salmonella serovars.

PubMed

Kang, Lin; Li, Nan; Li, Ping; Zhou, Yang; Gao, Shan; Gao, Hongwei; Xin, Wenwen; Wang, Jinglin

2017-04-01

Salmonella can cause global foodborne illnesses in humans and many animals. The current diagnostic gold standard used for detecting Salmonella infection is microbiological culture followed by serological confirmation tests. However, these methods are complicated and time-consuming. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) analysis offers some advantages in rapid identification, for example, simple and fast sample preparation, fast and automated measurement, and robust and reliable identification up to genus and species levels, possibly even to the strain level. In this study, we established a reference database for species identification using whole-cell MALDI-TOF MS; the database consisted of 12 obtained main spectra of the Salmonella culture collection strains belonged to seven serotypes. Eighty-two clinical isolates of Salmonella were identified using established database, and partial 16S rDNA gene sequencing and serological method were used as comparison. We found that MALDI-TOF mass spectrometry provided high accuracy in identification of Salmonella at species level but was limited to type or subtype Salmonella serovars. We also tried to find serovar-specific biomarkers and failed. Our study demonstrated that (a) MALDI-TOF MS was suitable for identification of Salmonella at species level with high accuracy and (b) that MALDI-TOF MS method presented in this study was not useful for serovar assignment of Salmonella currently, because of its low matching with serological method and (c) MALDI-TOF MS method presented in this study was not suitable to subtype S. typhimurium because of its low discriminatory ability.

The enhanced immune responses induced by Salmonella enteritidis ghosts loaded with Neisseria gonorrhoeae porB against Salmonella in mice.

PubMed

Jiao, Hongmei; Yang, Hui; Zhao, Dan; He, Li; Chen, Jin; Li, Guocai

2016-11-01

Human health has been seriously endangered by highly prevalent salmonellosis and multidrug-resistant Salmonella strains. Current vaccines suffer from variable immune-protective effects, so more effective ones are needed to control Salmonella infection : Bacterial ghosts have been produced by the expression of lysis gene E from bacteriophage PhiX174 and can be filled with considerable exogenous substances such as DNA or drugs as a novel platform. In this study, Salmonella enteritidis (SE) ghosts were developed and loaded with Neisseria gonorrhoeae porin B (porB) to construct a novel inactive vaccine. Our new studies show that SE ghosts loaded with porB displayed increased production of pro-inflammatory cytokines (IL-1β, IL-6, IL-10 and IL-12p70) in bone marrow-derived dendritic cells (BMDCs), and elicited significantly higher specific systemic and mucosal immune responses to Salmonella than SE ghosts alone. In addition, the novel porB-loaded ghosts conferred higher protective effects on virulent Salmonella challenge. For the first time, we demonstrate that N. gonorrhoeae porB, as a novel adjuvant, can increase the immunogenicity of SE ghosts. Our studies suggested that Salmonella enteritidis ghosts loaded with Neisseria gonorrhoeae porin B might be a useful mucosal Salmonella vaccine candidate for practical use in the future. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Characterization of the Salmonella enterica Serotype Isangi Isolated from Patients for the First Time in China.

PubMed

Li, Xin-Peng; Gao, Ri-Hong; Hou, Pei-Bin; Ren, Yan-Yan; Zhang, Hua-Ning; Jiang, Kui-Ying; Chen, Yu-Zhen; Qi, Zi-Gang; Xu, Min; Bi, Zhen-Wang

2017-08-01

No studies have reported the isolation of serotype Salmonella Isangi from cases of salmonellosis in mainland China. We investigated an outbreak of foodborne disease with salmonella and collected the samples from the patients and surplus foods. Salmonella strains were isolated and the serotype was identified according to the Kauffmann-White scheme. The relatedness of the isolates was determined using pulsed-field gel electrophoresis (PFGE) and whole genome sequencing (WGS). Antimicrobial susceptibility was conducted by the broth microdilution method. There were 74 diners in the case, 33 of which got ill, with an attack rate of 44.6% (33/74). A total of 24 samples were collected from the outbreak cases, six Salmonella Isangi strains were isolated and susceptible to all tested drugs. PFGE and WGS analysis suggested that the pathogen dissemination through a single or limited vector(s), the steamed fish and mixed food (fry spicy chicken, braised pork ribs, and goose leg), may be the source of infection or be cross-contaminated. We first report the characteristics of an outbreak and molecular strain relatedness of Salmonella Isangi in mainland China.

Real-time optotracing of curli and cellulose in live Salmonella biofilms using luminescent oligothiophenes.

PubMed

Choong, Ferdinand X; Bäck, Marcus; Fahlén, Sara; Johansson, Leif Bg; Melican, Keira; Rhen, Mikael; Nilsson, K Peter R; Richter-Dahlfors, Agneta

2016-01-01

Extracellular matrix (ECM) is the protein- and polysaccharide-rich backbone of bacterial biofilms that provides a defensive barrier in clinical, environmental and industrial settings. Understanding the dynamics of biofilm formation in native environments has been hindered by a lack of research tools. Here we report a method for simultaneous, real-time, in situ detection and differentiation of the Salmonella ECM components curli and cellulose, using non-toxic, luminescent conjugated oligothiophenes (LCOs). These flexible conjugated polymers emit a conformation-dependent fluorescence spectrum, which we use to kinetically define extracellular appearance of curli fibres and cellulose polysaccharides during bacterial growth. The scope of this technique is demonstrated by defining biofilm morphotypes of Salmonella enterica serovars Enteritidis and Typhimurium, and their isogenic mutants in liquid culture and on solid media, and by visualising the ECM components in native biofilms. Our reported use of LCOs across a number of platforms, including intracellular cellulose production in eukaryotic cells and in infected tissues, demonstrates the versatility of this optotracing technology, and its ability to redefine biofilm research.

Real-time optotracing of curli and cellulose in live Salmonella biofilms using luminescent oligothiophenes

PubMed Central

Choong, Ferdinand X; Bäck, Marcus; Fahlén, Sara; Johansson, Leif BG; Melican, Keira; Rhen, Mikael; Nilsson, K Peter R; Richter-Dahlfors, Agneta

2016-01-01

Extracellular matrix (ECM) is the protein- and polysaccharide-rich backbone of bacterial biofilms that provides a defensive barrier in clinical, environmental and industrial settings. Understanding the dynamics of biofilm formation in native environments has been hindered by a lack of research tools. Here we report a method for simultaneous, real-time, in situ detection and differentiation of the Salmonella ECM components curli and cellulose, using non-toxic, luminescent conjugated oligothiophenes (LCOs). These flexible conjugated polymers emit a conformation-dependent fluorescence spectrum, which we use to kinetically define extracellular appearance of curli fibres and cellulose polysaccharides during bacterial growth. The scope of this technique is demonstrated by defining biofilm morphotypes of Salmonella enterica serovars Enteritidis and Typhimurium, and their isogenic mutants in liquid culture and on solid media, and by visualising the ECM components in native biofilms. Our reported use of LCOs across a number of platforms, including intracellular cellulose production in eukaryotic cells and in infected tissues, demonstrates the versatility of this optotracing technology, and its ability to redefine biofilm research. PMID:28721253

Small-Scale Terrorist Attacks Using Chemical and Biological Agents: An Assessment Framework and Preliminary Comparisons

DTIC Science & Technology

2004-06-23

Vibrio cholerae ) + — — — + Unknown Salmonella Typhimurium + — + — — Unknown Typhoid fever (Salmonella Typhi) + O — — — Unknown Source: This...disseminated by contamination of food or drink. Cholera bb ( Vibrio cholerae ) Cholera occurs in many of the developing countries of Africa and Asia...diseaseinfo/cholera_g.htm]; the Health Canada Material Safety Data Sheet - Infectious Substances for Vibrio cholerae , found online at [http://www.hc-sc.gc.ca

Immunisation of chickens with live Salmonella vaccines - Role of booster vaccination.

PubMed

Methner, U

2018-05-17

It is accepted that booster vaccinations of chickens with live Salmonella vaccines are essential part of vaccinations schemes to induce an effective adaptive immune response. As manufacturer of registered live Salmonella vaccines recommend different times of booster the question raises whether the duration between the first and second immunisation might influence the protective effect against Salmonella exposure. Chickens were immunised with a live Salmonella Enteritidis vaccine on day 1 of age followed by a booster vaccination at different intervals (day 28, 35 or 42 of age) to study the effects on the colonisation and invasion of the Salmonella vaccine strain, the humoral immune response and the efficacy against infection with Salmonella Enteritidis on day 56 of age. Immunisation of all groups resulted in a very effective adaptive immune response and a high degree of protection against severe Salmonella exposure, however, the time of booster had only an unverifiable influence on either the colonisation of the vaccine strain, the development of the humoral immune response or the colonisation of the Salmonella challenge strain. Therefore, the first oral immunisation of the chicks on day 1 of age seems to be of special importance and prerequisite for the development of the effective immune response. A booster immunisation should be carried out, however, the time of booster may vary between week 3 and week 7 of age of the chickens without adversely impact on the efficacy of the adaptive immune response or the protective effects. Copyright © 2018 Elsevier Ltd. All rights reserved.

The relationship between the numbers of Salmonella Enteritidis, Salmonella Heidelberg, or Salmonella Hadar colonizing reproductive tissues of experimentally infected laying hens and deposition inside eggs.

PubMed

Gast, Richard K; Guraya, Rupa; Guard, Jean; Holt, Peter S

2011-06-01

Contamination of eggs by Salmonella Enteritidis has been a prominent cause of human illness for several decades and is the focus of a recently implemented national regulatory plan for egg-producing flocks in the United States. Salmonella Heidelberg has also been identified as an egg-transmitted pathogen. The deposition of Salmonella strains inside eggs is a consequence of reproductive tract colonization in infected laying hens, but prior research has not determined the relationship between the numbers of Salmonella that colonize reproductive organs and the associated frequency of egg contamination. In the present study, groups of laying hens in two trials were experimentally infected with large oral doses of strains of Salmonella Enteritidis (phage type 13a), Salmonella Heidelberg, or Salmonella Hadar. Reproductive tissues of selected hens were cultured to detect and enumerate Salmonella at 5 days postinoculation, and the interior contents of eggs laid between 6 and 25 days postinoculation were tested for contamination. Significantly more internally contaminated eggs were laid by hens infected with Salmonella Enteritidis (3.58%) than with strains of either Salmonella Heidelberg (0.47%) or Salmonella Hadar (0%). However, no significant differences were observed between Salmonella strains in either isolation frequency or the number of colony-forming units (CFU) isolated from ovaries or oviducts. Salmonella isolation frequencies ranged from 20.8% to 41.7% for ovaries and from 8.3% to 33.3% for oviducts. Mean Salmonella colonization levels ranged from 0.10 to 0.51 log CFU/g for ovaries and from 0.25 to 0.46 log CFU/g for oviducts. Although parallel rank-orders were observed for Salmonella enumeration (in both ovaries and oviducts) and egg contamination frequency, a statistically significant relationship could not be established between these two parameters of infection.

Impact of litter Salmonella status during feed withdrawal on Salmonella recovery from the broiler crop and ceca.

PubMed

Buhr, R J; Bourassa, D V; Hinton, A; Fairchild, B D; Ritz, C W

2017-12-01

Research was conducted to evaluate the impact of litter Salmonella status during feed withdrawal on Salmonella recovery from the crop and ceca following feed withdrawal. In 4 experiments, pens of broilers in separate rooms were challenged with marker strains of either Salmonella Montevideo or Salmonella Heidelberg. Three d post challenge, a 12-hour feed withdrawal was initiated, and one pen of broilers was switched between rooms for each Salmonella serotype. In experiments 3 and 4, non-challenged broilers also were added to the Salmonella challenge pens. The litter of each pen was sampled before and after the feed withdrawal period, the broilers euthanized, and the crop and ceca aseptically removed for Salmonella isolation. Results showed that only the challenge Salmonella serotype was recovered from the litter in challenge pens where broilers were not moved, while both Salmonella serotypes were recovered from the litter of the switched pens. Salmonella was recovered from 56/80 crops and from 66/80 ceca of challenged broilers that remained in the challenge pens. The challenge Salmonella serotype was recovered from 50/80 crops and from 60/80 ceca, and the switched pens' litter Salmonella serotype was recovered from 19/80 crops but not from the ceca in broilers challenged with Salmonella and then switched between pens. For experiments 3 and 4, Salmonella was recovered from 19/40 crops and from only 2/40 ceca from the non-challenged broilers placed into the Salmonella challenge pens. The results from broilers that were switched between Salmonella challenge pens indicate that the recovery of Salmonella from the crop of broilers following feed withdrawal (on Salmonella-contaminated litter) appears to depend mainly on the initial challenge Salmonella (62%) and less on the litter Salmonella (24%) status during the feed withdrawal period. In contrast, only the initial challenge Salmonella was recovered from the ceca (79%) from broilers that remained in challenge pens or

Typhoid outbreak in Songkhla, Thailand 2009-2011: clinical outcomes, susceptibility patterns, and reliability of serology tests.

PubMed

Limpitikul, Wannee; Henpraserttae, Narong; Saksawad, Rachanee; Laoprasopwattana, Kamolwish

2014-01-01

To determine the clinical manifestations and outcomes, the reliability of Salmonella enterica serotype Typhi (S ser. Typhi) IgM and IgG rapid tests, and the susceptibility patterns and the response to treatment during the 2009-2011 typhoid outbreak in Songkhla province in Thailand. The medical records of children aged <15 years with S ser. Typhi bacteremia were analysed. The efficacy of the typhoid IgM and IgG rapid tests and susceptibility of the S ser. Typhi to the current main antibiotics used for typhoid (amoxicillin, ampicillin, cefotaxime, ceftriaxone, co-trimoxazole, and ciprofloxacin), were evaluated. S ser. Typhi bacteremia was found in 368 patients, and all isolated strains were susceptible to all 6 antimicrobials tested. Most of the patients were treated with ciprofloxacin for 7-14 days. The median time (IQR) of fever before treatment and duration of fever after treatment were 5 (4, 7) days and 4 (3, 5) days, respectively. Complications of ascites, lower respiratory symptoms, anemia (Hct <30%), and ileal perforation were found in 7, 7, 22, and 1 patients, respectively. None of the patients had recurrent infection or died. The sensitivities of the typhoid IgM and IgG tests were 58.3% and 25.6% respectively, and specificities were 74.1% and 50.5%, respectively. Most of the patients were diagnosed at an early stage and treated with a good outcome. All S ser. Typhi strains were susceptible to standard first line antibiotic typhoid treatment. The typhoid IgM and IgG rapid tests had low sensitivity and moderate specificity.

Structural analysis of the O-acetylated O-polysaccharide isolated from Salmonella paratyphi A and used for vaccine preparation.

PubMed

Ravenscroft, N; Cescutti, P; Gavini, M; Stefanetti, G; MacLennan, C A; Martin, L B; Micoli, F

2015-03-02

Salmonella paratyphi A is increasingly recognized as a common cause of enteric fever cases and there are no licensed vaccines against this infection. Antibodies directed against the O-polysaccharide of the lipopolysaccharide of Salmonella are protective and conjugation of the O-polysaccharide to a carrier protein represents a promising strategy for vaccine development. O-Acetylation of S. paratyphi A O-polysaccharide is considered important for the immunogenicity of S. paratyphi A conjugate vaccines. Here, as part of a programme to produce a bivalent conjugate vaccine against both S. typhi and S. paratyphi A diseases, we have fully elucidated the O-polysaccharide structure of S. paratyphi A by use of HPLC-SEC, HPAEC-PAD/CD, GLC, GLC-MS, 1D and 2D-NMR spectroscopy. In particular, chemical and NMR studies identified the presence of O-acetyl groups on C-2 and C-3 of rhamnose in the lipopolysaccharide repeating unit, at variance with previous reports of O-acetylation at a single position. Moreover HR-MAS NMR analysis performed directly on bacterial pellets from several strains of S. paratyphi A also showed O-acetylation on C-2 and C-3 of rhamnose, thus this pattern is common and not an artefact from O-polysaccharide purification. Conjugation of the O-polysaccharide to the carrier protein had little impact on O-acetylation and therefore should not adversely affect the immunogenicity of the vaccine. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

Report: Studies on antibacterial activity of some traditional medicinal plants used in folk medicine.

PubMed

Israr, Fozia; Hassan, Fouzia; Naqvi, Baqir Shyum; Azhar, Iqbal; Jabeen, Sabahat; Hasan, S M Farid

2012-07-01

Ethanolic extracts of eight medicinal plants commonly used in folk medicine were tested for their antibacterial activity against four Gram positive strains (Bacillus subtilis, Staphylococcus aureus, Staphylococcus epidermidis and, Streptococcus pneumoniae) and six Gram negative strains (Escherichia coli, Proteus vulgaris, Proteus mirabilis. Salmonella typhi para A, Salmonella typhi para B and Shigella dysenteriae) that were obtained from different pathological laboratories located in Karachi, Pakistan. Disc diffusion method was used to analyze antibacterial activity. Out of eight, five medicinal plants showed antibacterial activity against two or more than two microbial species. The most effective antimicrobial plant found to be Punica granatum followed by Curcuma zedoaria Rosc, Grewia asiatica L and Carissa carandas L, Curcuma caesia Roxb respectively. From these results, it is evident that medicinal plants could be used as a potential source of new antibacterial agents.

Influence of modified atmosphere and varying time in storage on the irradiation sensitivity of Salmonella on sliced roma tomatoes

NASA Astrophysics Data System (ADS)

Niemira, Brendan A.; Boyd, Glenn

2013-09-01

Salmonella contamination of tomatoes is a recurrent food safety concern. Irradiation inactivates pathogens on fresh and fresh cut produce. However, the interaction of time in refrigerated storage and modified atmosphere packaging (MAP) may influence the response of pathogens to irradiation. Roma tomatoes were sliced and inoculated with a cocktail of outbreak strains of Salmonella. The inoculated tomatoes were packaged under one of four atmospheres: air, 10/90 O2/N2, 5/95 O2/N2 or 100% N2. The packages were kept in refrigerated storage (10 °C) for various times after inoculation, to simulate the potential time delay between packaging and irradiation treatment. Tomatoes were irradiated immediately (0 h), or after 24 or 48 h in storage. The surviving populations were recovered and enumerated. Irradiation effectively reduced Salmonella at all times. Estimated D10 value (the dose necessary for 1 log reduction) varied significantly among the combinations of time and MAP, ranging from 0.165-0.335 kGy. Tomatoes packaged in air, irradiated at 0 h, had a D10 of 0.165 kGy; all other combinations showed significantly higher D10. Reduced oxygen generally resulted in higher D10 values, with the highest D10 of 0.335 kGy obtained for 100% N2, 0 h. Time in storage pre-irradiation tended to increase D10 for air and 5/95 O2/N2, but not for 10/90 O2/N2 or 100% N2. These results suggest that time required for refrigerated holding of processed Roma tomatoes or shipment to an off-site irradiation service provider may alter the efficacy of irradiation if reduced oxygen MAP is used.

From Exit to Entry: Long-term Survival and Transmission of Salmonella

PubMed Central

Waldner, Landon L.; MacKenzie, Keith D.; Köster,, Wolfgang; White, Aaron P.

2012-01-01

Salmonella spp. are a leading cause of human infectious disease worldwide and pose a serious health concern. While we have an improving understanding of pathogenesis and the host-pathogen interactions underlying the infection process, comparatively little is known about the survival of pathogenic Salmonella outside their hosts. This review focuses on three areas: (1) in vitro evidence that Salmonella spp. can survive for long periods of time under harsh conditions; (2) observations and conclusions about Salmonella persistence obtained from human outbreaks; and (3) new information revealed by genomic- and population-based studies of Salmonella and related enteric pathogens. We highlight the mechanisms of Salmonella persistence and transmission as an essential part of their lifecycle and a prerequisite for their evolutionary success as human pathogens. PMID:25436767

A rabbit model of non-typhoidal Salmonella bacteremia.

PubMed

Panda, Aruna; Tatarov, Ivan; Masek, Billie Jo; Hardick, Justin; Crusan, Annabelle; Wakefield, Teresa; Carroll, Karen; Yang, Samuel; Hsieh, Yu-Hsiang; Lipsky, Michael M; McLeod, Charles G; Levine, Myron M; Rothman, Richard E; Gaydos, Charlotte A; DeTolla, Louis J

2014-09-01

Bacteremia is an important cause of morbidity and mortality in humans. In this study, we focused on the development of an animal model of bacteremia induced by non-typhoidal Salmonella. New Zealand White rabbits were inoculated with a human isolate of non-typhoidal Salmonella strain CVD J73 via the intra-peritoneal route. Blood samples were collected at specific time points and at euthanasia from infected rabbits. Additionally, tissue samples from the heart, lungs, spleen, gastrointestinal tract, liver and kidneys were obtained at euthanasia. All experimentally infected rabbits displayed clinical signs of disease (fever, dehydration, weight loss and lethargy). Tissues collected at necropsy from the animals exhibited histopathological changes indicative of bacteremia. Non-typhoidal Salmonella bacteria were detected in the blood and tissue samples of infected rabbits by microbiological culture and real-time PCR assays. The development of this animal model of bacteremia could prove to be a useful tool for studying how non-typhoidal Salmonella infections disseminate and spread in humans. Copyright © 2014 Elsevier Ltd. All rights reserved.

Samsung Salmonella Detection Kit. AOAC Performance Tested Method(SM) 021203.

PubMed

Li, Jun; Cheung, Win Den; Opdyke, Jason; Harvey, John; Chong, Songchun; Moon, Cheol Gon

2012-01-01

Salmonella, one of the most common causes of foodborne illness, is a significant public health concern worldwide. There is a need in the food industry for methods that are simple, rapid, and sensitive for the detection of foodborne pathogens. In this study, the Samsung Salmonella Detection Kit, a real-time PCR assay for the detection of Salmonella, was evaluated according to the current AOAC guidelines. The validation consisted of lot-to-lot consistency, stability, robustness, and inclusivity/exclusivity studies, as well as a method comparison of 10 different food matrixes. In the validation, the Samsung Salmonella Detection Kit was used in conjunction with the Applied Biosystems StepOnePlus PCR system and the Samsung Food Testing Software for the detection of Salmonella species. The performance of the assays was compared to the U.S. Department of Agriculture/Food Safety and Inspection Service-Microbiology Laboratory Guidebook (USDA/FSIS-MLG) 4.05: Isolation and Identification of Salmonella from Meat, Poultry, Pasteurized Egg, and Catfish and the and U.S. Food and Drug Administration/Bacteriological Analytical Manual (FDA/BAM) Chapter 5 Salmonella reference methods. The validation was conducted using an unpaired study design for detection of Salmonella spp. in raw ground beef, raw pork, raw ground pork, raw chicken wings, raw salmon, alfalfa sprouts, pasteurized orange juice, peanut butter, pasteurized whole milk, and shell eggs. The Samsung Salmonella Detection Kit demonstrated lot-to-lot consistency among three independent lots as well as ruggedness with minor modifications to changes in enrichment incubation time, enrichment incubation temperature, and DNA sample volume for PCR reaction. Stability was observed for 13 months at -20 degrees C and 3 months at 5 degrees C. For the inclusivity/exclusivity study, the Samsung Salmonella Detection Kit correctly identified 147 Salmonella species isolates out of 147 isolates tested from each of three different enrichment

Atmospheric pressure plasma jet treatment of Salmonella Enteritidis inoculated eggshells.

PubMed

Moritz, Maike; Wiacek, Claudia; Koethe, Martin; Braun, Peggy G

2017-03-20

Contamination of eggshells with Salmonella Enteritidis remains a food safety concern. In many cases human salmonellosis within the EU can be traced back to raw or undercooked eggs and egg products. Atmospheric pressure plasma is a novel decontamination method that can reduce a wide range of pathogens. The aim of this work was to evaluate the possibility of using an effective short time cold plasma treatment to inactivate Salmonella Enteritidis on the eggshell. Therefore, artificially contaminated eggshells were treated with an atmospheric pressure plasma jet under different experimental settings with various exposure times (15-300s), distances from the plasma jet nozzle to the eggshell surface (5, 8 or 12mm), feed gas compositions (Ar, Ar with 0.2, 0.5 or 1.0% O 2 ), gas flow rates (5 and 7slm) and different inoculations of Salmonella Enteritidis (10 1 -10 6 CFU/cm 2 ). Atmospheric pressure plasma could reduce Salmonella Enteritidis on eggshells significantly. Reduction factors ranged between 0.22 and 2.27 log CFU (colony-forming units). Exposure time and, particularly at 10 4 CFU/cm 2 inoculation, feed gas had a major impact on Salmonella reduction. Precisely, longer exposure times led to higher reductions and Ar as feed gas was more effective than ArO 2 mixtures. Copyright © 2017 Elsevier B.V. All rights reserved.

Thermal inactivation of Salmonella spp. in pork burger patties.

PubMed

Gurman, P M; Ross, T; Holds, G L; Jarrett, R G; Kiermeier, A

2016-02-16

Predictive models, to estimate the reduction in Escherichia coli O157:H7 concentration in beef burgers, have been developed to inform risk management decisions; no analogous model exists for Salmonella spp. in pork burgers. In this study, "Extra Lean" and "Regular" fat pork minces were inoculated with Salmonella spp. (Salmonella 4,[5],12,i:-, Salmonella Senftenberg and Salmonella Typhimurium) and formed into pork burger patties. Patties were cooked on an electric skillet (to imitate home cooking) to one of seven internal temperatures (46, 49, 52, 55, 58, 61, 64 °C) and Salmonella enumerated. A generalised linear logistic regression model was used to develop a predictive model for the Salmonella concentration based on the internal endpoint temperature. It was estimated that in pork mince with a fat content of 6.1%, Salmonella survival will be decreased by -0.2407log10 CFU/g for a 1 °C increase in internal endpoint temperature, with a 5-log10 reduction in Salmonella concentration estimated to occur when the geometric centre temperature reaches 63 °C. The fat content influenced the rate of Salmonella inactivation (P=0.043), with Salmonella survival increasing as fat content increased, though this effect became negligible as the temperature approached 62 °C. Fat content increased the time required for patties to achieve a specified internal temperature (P=0.0106 and 0.0309 for linear and quadratic terms respectively), indicating that reduced fat pork mince may reduce the risk of salmonellosis from consumption of pork burgers. Salmonella serovar did not significantly affect the model intercepts (P=0.86) or slopes (P=0.10) of the fitted logistic curve. This predictive model can be applied to estimate the reduction in Salmonella in pork burgers after cooking to a specific endpoint temperature and hence to assess food safety risk. Crown Copyright © 2015. Published by Elsevier B.V. All rights reserved.

Improvement of sampling plans for Salmonella detection in pooled table eggs by use of real-time PCR.

PubMed

Pasquali, Frédérique; De Cesare, Alessandra; Valero, Antonio; Olsen, John Emerdhal; Manfreda, Gerardo

2014-08-01

Eggs and egg products have been described as the most critical food vehicles of salmonellosis. The prevalence and level of contamination of Salmonella on table eggs are low, which severely affects the sensitivity of sampling plans applied voluntarily in some European countries, where one to five pools of 10 eggs are tested by the culture based reference method ISO 6579:2004. In the current study we have compared the testing-sensitivity of the reference culture method ISO 6579:2004 and an alternative real-time PCR method on Salmonella contaminated egg-pool of different sizes (4-9 uninfected eggs mixed with one contaminated egg) and contamination levels (10°-10(1), 10(1)-10(2), 10(2)-10(3)CFU/eggshell). Two hundred and seventy samples corresponding to 15 replicates per pool size and inoculum level were tested. At the lowest contamination level real-time PCR detected Salmonella in 40% of contaminated pools vs 12% using ISO 6579. The results were used to estimate the lowest number of sample units needed to be tested in order to have a 95% certainty not falsely to accept a contaminated lot by Monte Carlo simulation. According to this simulation, at least 16 pools of 10 eggs each are needed to be tested by ISO 6579 in order to obtain this confidence level, while the minimum number of pools to be tested was reduced to 8 pools of 9 eggs each, when real-time PCR was applied as analytical method. This result underlines the importance of including analytical methods with higher sensitivity in order to improve the efficiency of sampling and reduce the number of samples to be tested. Copyright © 2013 Elsevier B.V. All rights reserved.

Salmonella risk to consumers via pork is related to the Salmonella prevalence in pig feed.

PubMed

Rönnqvist, M; Välttilä, V; Ranta, J; Tuominen, P

2018-05-01

Pigs are an important source of human infections with Salmonella, one of the most common causes of sporadic gastrointestinal infections and foodborne outbreaks in the European region. Feed has been estimated to be a significant source of Salmonella in piggeries in countries of a low Salmonella prevalence. To estimate Salmonella risk to consumers via the pork production chain, including feed production, a quantitative risk assessment model was constructed. The Salmonella prevalence in feeds and in animals was estimated to be generally low in Finland, but the relative importance of feed as a source of Salmonella in pigs was estimated as potentially high. Discontinuation of the present strict Salmonella control could increase the risk of Salmonella in slaughter pigs and consequent infections in consumers. The increased use of low risk and controlled feed ingredients could result in a consistently lower residual contamination in pigs and help the tracing and control of the sources of infections. Copyright © 2017 Elsevier Ltd. All rights reserved.

Small-Scale Terrorist Attacks Using Chemical and Biological Agents: An Assessment Framework and Preliminary Comparisons

DTIC Science & Technology

2004-05-20

Unknown Cholera ( Vibrio cholerae ) + — — — + Unknown Salmonella Typhimurium + — + — — Unknown Typhoid fever (Salmonella Typhi) + O — — — Unknown... Cholera bb ( Vibrio cholerae ) Cholera occurs in many of the developing countries of Africa and Asia, especially where sanitary conditions are not optimal...Safety Data Sheet - Infectious Substances for Vibrio cholerae , found online at [http://www.hc-sc.gc.ca/pphb-dgspsp/msds-ftss/msds164e.html]; D. Hank

[Susceptibility to azithromycin and other antibiotics in recent isolates of Salmonella, Shigella and Yersinia].

PubMed

Martín-Pozo, Angeles; Arana, David M; Fuentes, Miriam; Alós, Juan-Ignacio

2014-01-01

Azithromycin represents an alternative option to treat bacterial diarrhea when the antibiotic therapy is indicated. Little is known regarding the susceptibility to azithromycin in enteropathogens in Spain. The MICs of azithromycin were determined by E-test against Salmonella non-typhi (SNT), Shigella and Yersinia isolates collected over the last three years (2010-2012). In addition, the susceptibility to other antibiotics usually used to treat gastrointestinal diseases was determined in these isolates by using a microdilution method. A total of 139 strains of SNT, Shigella and Yersinia were studied. All of them, except one strain, had a MIC≤16mg/L of azithromycin. In the adult population, 14.7% and 40.6% of SNT and Shigella isolates, respectively, were resistant to at least 2 of following antibiotics: amoxicillin, trimethoprim-sulfamethoxazole and ciprofloxacin. In the pediatric population, 10% of SNT clinical isolates and 28.6% (2/7) of Shigella isolates were resistant to amoxicillin and trimethoprim-sulfamethoxazole. In our experience, azithromycin would be a useful antibiotic alternative to treat bacterial diarrhea. Copyright © 2013 Elsevier España, S.L. y Sociedad Española de Enfermedades Infecciosas y Microbiología Clínica. All rights reserved.

A longitudinal study of Salmonella from snakes used in a public outreach program.

PubMed

Goupil, Brad A; Trent, Ava M; Bender, Jeff; Olsen, Karen E; Morningstar, Brenda R; Wünschmann, Arno

2012-12-01

Snakes are considered to be a source of Salmonella infection for humans, but little is known about the actual serotype prevalence in healthy snakes over time. Twelve snakes involved in a public outreach program, representing seven different species, were tested weekly for shedding of Salmonella sp. over a period of 10 consecutive weeks. The snakes were housed in close proximity but in separate exhibits. Fresh fecal samples (when available) or cloacal swabs were cultured for Salmonella sp., and subsequent Salmonella isolates were serotyped. As representatives of the feed source, the feces of two mice and the intestines of one rat were cultured weekly. Fecal samples from 11 of the 12 snakes were positive for Salmonella at least once. Seven (58%) of 12 snakes were culture positive five times or more. The weekly prevalence of Salmonella shedding varied between 25% and 66%. Two or more different serotypes were isolated from nine snakes over time; however, a predominant serotype was generally isolated from each of these snakes. Altogether 15 different serotypes were identified. Serotypes of public health concern included Newport, Oranienburg, and Muenchen. Two samples from feeder rodents were positive for Salmonella. The results are consistent with previous studies showing high intestinal colonization rates with Salmonella sp. in snakes. Frequent and intermittent shedding of multiple serotypes was evident. Feeder rodents might serve as a source for intestinal colonization. Appropriate handling protocols should be implemented for all reptiles associated with public outreach programs to minimize risk of Salmonella transmission to the public.

Control of Salmonella enterica serovar Enteritidis in laying hens by inactivated Salmonella Enteritidis vaccines

PubMed Central

de Freitas Neto, Oliveiro Caetano; Mesquita, Aline Lopes; de Paiva, Jaqueline Boldrin; Zotesso, Fábio; Berchieri Júnior, Angelo

2008-01-01

Salmonella Enteritidis is one of the agents that is responsible for outbreaks of human foodborne salmonellosis caused by Salmonella Enteritidis and is generally associated with the consumption of poultry products. Inactivated Salmonella Enteritidis cell vaccine is one of the available methods to control Salmonella Enteritidis in breeders and laying hens, however results in terms of efficacy vary. This vaccine has never been tested in Brazil, therefore, the present work was carried out to assess three commercial inactivated Salmonella Enteritidis vaccines allowed in Brazil. Four hundred white light variety commercial laying hens were obtained at one-day-of age. At eight weeks old, the birds were divided into four groups with one hundred animals each. Birds from three groups (V1, V2 and V3) received different intramuscular vaccines, followed by a booster dose at 16 weeks of age. Birds from another group (CG) were not vaccinated. When the laying hens were 20, 25 and 31 weeks old, 13 from each group were transferred to another room and were challenged by inoculating 2 mL neat culture of Salmonella Enteritidis. On the second day after each challenge, the caecal contents, spleen, liver and ovary of three birds from each group were analyzed for the presence of Salmonella Enteritidis. Twice a week a cloacal swab of each bird was taken and all eggs laid were examined for the presence of Salmonella Enteritidis. After four consecutive negative cloacal swabs in all the groups, the birds were sacrificed so as to examine the liver, caecal contents and ovaries. Overall, the inactivated vaccine used in group V3 reduced Salmonella Enteritidis in the feces and eggs. A very small amount of Salmonella was found in the spleen, liver, ovary and caeca of the birds in the four groups during the whole experiment. In general, inactivated Salmonella Enteritidis vaccines was able to decrease the presence of Salmonella Enteritidis in the birds and in the eggs as well. Nevertheless, they must

Use of Attenuated but Metabolically Competent Salmonella as a Probiotic To Prevent or Treat Salmonella Infection

PubMed Central

Sabag-Daigle, Anice; Blunk, Henry M.; Gonzalez, Juan F.; Steidley, Brandi L.; Boyaka, Prosper N.

2016-01-01

Salmonella enterica is among the most burdensome of foodborne disease agents. There are over 2,600 serovars that cause a range of disease manifestations ranging from enterocolitis to typhoid fever. While there are two vaccines in use in humans to protect against typhoid fever, there are none that prevent enterocolitis. If vaccines preventing enterocolitis were to be developed, they would likely protect against only one or a few serovars. In this report, we tested the hypothesis that probiotic organisms could compete for the preferred nutrient sources of Salmonella and thus prevent or treat infection. To this end, we added the fra locus, which encodes a utilization pathway for the Salmonella-specific nutrient source fructose-asparagine (F-Asn), to the probiotic bacterium Escherichia coli Nissle 1917 (Nissle) to increase its ability to compete with Salmonella in mouse models. We also tested a metabolically competent, but avirulent, Salmonella enterica serovar Typhimurium mutant for its ability to compete with wild-type Salmonella. The modified Nissle strain became more virulent and less able to protect against Salmonella in some instances. On the other hand, the modified Salmonella strain was safe and effective in preventing infection with wild-type Salmonella. While we tested for efficacy only against Salmonella Typhimurium, the modified Salmonella strain may be able to compete metabolically with most, if not all, Salmonella serovars, representing a novel approach to control of this pathogen. PMID:27185789

Nano-materials for use in sensing of salmonella infections: Recent advances.

PubMed

Pashazadeh, Paria; Mokhtarzadeh, Ahad; Hasanzadeh, Mohammad; Hejazi, Maryam; Hashemi, Maryam; de la Guardia, Miguel

2017-01-15

Salmonella infectious diseases spreading every day through food have become a life-threatening problem for millions of people and growing menace to society. Health expert's estimate that the yearly cost of all the food borne diseases is approximately $5-6 billion. Traditional methodologies for salmonella analysis provide high reliability and very low limits of detection. Among them immunoassays and Nucleic acid-based assays provide results within 24h, but they are expensive, tedious and time consuming. So, there is an urgent need for development of rapid, robust and cost-effective alternative technologies for real-time monitoring of salmonella. Several biosensors have been designed and commercialized for detection of this pathogen in food and water. In this overview, we have updated the literature concerning novel biosensing methods such as various optical and electrochemical biosensors and newly developed nano- and micro-scaled and aptamers based biosensors for detection of salmonella pathogen. Furthermore, attention has been focused on the principal concepts, applications, and examples that have been achieved up to diagnose salmonella. In addition, commercial biosensors and foreseeable future trends for onsite detecting salmonella have been summarized. Copyright © 2016 Elsevier B.V. All rights reserved.

Two Novel Salmonella Bivalent Vaccines Confer Dual Protection against Two Salmonella Serovars in Mice

PubMed Central

Zhao, Xinxin; Dai, Qinlong; Jia, Renyong; Zhu, Dekang; Liu, Mafeng; Wang, Mingshu; Chen, Shun; Sun, Kunfeng; Yang, Qiao; Wu, Ying; Cheng, Anchun

2017-01-01

Non-typhoidal Salmonella includes thousands of serovars that are leading causes of foodborne diarrheal illness worldwide. In this study, we constructed three bivalent vaccines for preventing both Salmonella Typhimurium and Salmonella Newport infections by using the aspartate semialdehyde dehydrogenase (Asd)-based balanced-lethal vector-host system. The constructed Asd+ plasmid pCZ11 carrying a subset of the Salmonella Newport O-antigen gene cluster including the wzx-wbaR-wbaL-wbaQ-wzy-wbaW-wbaZ genes was introduced into three Salmonella Typhimurium mutants: SLT19 (Δasd) with a smooth LPS phenotype, SLT20 (Δasd ΔrfbN) with a rough LPS phenotype, and SLT22 (Δasd ΔrfbN ΔpagL::T araC PBAD rfbN) with a smooth LPS phenotype when grown with arabinose. Immunoblotting demonstrated that SLT19 harboring pCZ11 [termed SLT19 (pCZ11)] co-expressed the homologous and heterologous O-antigens; SLT20 (pCZ11) exclusively expressed the heterologous O-antigen; and when arabinose was available, SLT22 (pCZ11) expressed both types of O-antigens, while in the absence of arabinose, SLT22 (pCZ11) expressed only the heterologous O-antigen. Exclusive expression of the heterologous O-antigen in Salmonella Typhimurium decreased the swimming ability of the bacterium and its susceptibility to polymyxin B. Next, the crp gene was deleted from the three recombinant strains for attenuation purposes, generating the three bivalent vaccine strains SLT25 (pCZ11), SLT26 (pCZ11), and SLT27 (pCZ11), respectively. Groups of BALB/c mice (12 mice/group) were orally immunized with 109 CFU of each vaccine strain twice at an interval of 4 weeks. Compared with a mock immunization, immunization with all three vaccine strains induced significant serum IgG responses against both Salmonella Typhimurium and Salmonella Newport LPS. The bacterial loads in the mouse tissues were significantly lower in the three vaccine-strain-immunized groups than in the mock group after either Salmonella Typhimurium or Salmonella

Antimicrobial resistance in zoonotic nontyphoidal Salmonella: an alarming trend?

PubMed

Michael, G B; Schwarz, S

2016-12-01

Zoonotic bacteria of the genus Salmonella have acquired various antimicrobial resistance properties over the years. The corresponding resistance genes are commonly located on plasmids, transposons, gene cassettes, or variants of the Salmonella Genomic Islands SGI1 and SGI2. Human infections by nontyphoidal Salmonella isolates mainly result from ingestion of contaminated food. The two predominantly found Salmonella enterica subsp. enterica serovars in the USA and in Europe are S. Enteritidis and S. Typhimurium. Many other nontyphoidal Salmonella serovars have been implicated in foodborne Salmonella outbreaks. Summary reports of the antimicrobial susceptibility patterns of nontyphoidal Salmonella isolates over time suggest a moderate to low level of antimicrobial resistance and multidrug-resistance. However, serovar-specific analyses showed in part a steady state, a continuous decline, or a recent increase in resistance to certain antimicrobial agents. Resistance to critically important antimicrobial agents, e.g. third-generation cephalosporins and (fluoro)quinolones is part of many monitoring programmes and the corresponding results confirm that extended-spectrum β-lactamases are still rarely found in nontyphoidal Salmonella serovars, whereas resistance to (fluoro)quinolones is prevalent at variable frequencies among different serovars from humans and animals in different countries. Although it is likely that nontyphoidal Salmonella isolates from animals represent a reservoir for resistance determinants, it is mostly unknown where and when Salmonella isolates acquired resistance properties and which exchange processes have happened since then. Copyright © 2016 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

[Use of bacteriphages against Salmonella Enteritidis: a prevention tool].

PubMed

García, Cristina; Marín, Clara; Catalá-Gregori, Pablo; Soriano, Jose Miguel

2015-06-01

Salmonellosis is a highly prevalent disease still searching for preventive tools to avoid contamination level priority public health. The in vitro effect of bacteriophages against Salmonella enteritidis was evaluated as a prevention tool. Two tests with three concentrations of bacteriophages were conducted against two strains of Salmonella Enteritidis inoculated in fresh faeces of laying hens. Each test had a positive control. Thus, four groups in each test were evaluated. Each experimental group included two replicates, and three plates were incubated per replicate. The concentrations tested were three: commercial solution (5 × 10(7) pfu/mL), and two dilutions (1/10 and 1/30). One of the strains tested was CECT 4300, a certified strain of Colección Española de Cultivo Tipo and the other a field isolated strain in a sacrificed hen farm. Both strains were inoculated at 1.3 × 10(5) cfu/g of faeces in each of the four groups. Isolation and identification of bacteria by ISO6579 was done at various times after inoculation: 1 minute, 24 hours and 7 days. In the first test, with certified strain, Salmonella was isolated in all groups at time 1 minute. After 24 hours, Salmonella was isolated in all groups except in one of the replicas treated with 1/10 dilution of bacteriophages, one of the other replica plate treated with 1/10 dilution, and two plates of the two replicas treated with the commercial solution. After 7 days, the bacteria were not isolated from any of the experimental groups. In the second test, with the field strain, Salmonella was isolated in all groups at time 1 minute. After 24 hours, Salmonella was isolated in all groups except in one of the replicas treated with 1/10 dilution of bacteriophages and the two replicas treated with the commercial solution. Salmonella was not isolated in any of the experimental groups at 7 days. The use of bacteriophages reduced Salmonella enteritidis isolates in faeces at 24 hours after the application, so it could be

Prevalence and Characterization of Salmonella enterica and Salmonella Bacteriophages Recovered from Beef Cattle Feedlots in South Texas.

PubMed

Xie, Yicheng; Savell, Jeffrey W; Arnold, Ashley N; Gehring, Kerri B; Gill, Jason J; Taylor, T Matthew

2016-08-01

Asymptomatic Salmonella carriage in beef cattle is a food safety concern, and the beef feedlot environment may function as a reservoir of this pathogen. The goal of this study was to identify and isolate Salmonella and Salmonella bacteriophages from beef cattle feedlot environments in order to better understand the microbial ecology of Salmonella and identify phages that might be useful as anti-Salmonella beef safety interventions. Three feedlots in south Texas were visited, and 27 distinct samples from each source were collected from dropped feces, feed from feed bunks, drinking water from troughs, and soil in cattle pens (n = 108 samples). Preenrichment, selective enrichment, and selective/differential isolation of Salmonella were performed on each sample. A representative subset of presumptive Salmonella isolates was prepared for biochemical identification and serotyping. Samples were pooled by feedlot and sample type to create 36 samples and enriched to recover phages. Recovered phages were tested for host range against two panels of Salmonella hosts. Salmonella bacteria were identified in 20 (18.5%) of 108 samples by biochemical and/or serological testing. The serovars recovered included Salmonella enterica serovars Anatum, Muenchen, Altona, Kralingen, Kentucky, and Montevideo; Salmonella Anatum was the most frequently recovered serotype. Phage-positive samples were distributed evenly over the three feedlots, suggesting that phage prevalence is not strongly correlated with the presence of culturable Salmonella. Phages were found more frequently in soil and feces than in feed and water samples. The recovery of bacteriophages in the Salmonella-free feedlot suggests that phages might play a role in suppressing the Salmonella population in a feedlot environment.

Salmonellae Associated with Further-processed Turkey Products1

PubMed Central

Bryan, Frank L.; Ayres, John C.; Kraft, Allen A.

1968-01-01

“Further-processed” turkey products, prepared from chilled, eviscerated, and thawed carcasses at two commercial turkey-processing plants, were evaluated, for the presence of salmonellae. These organisms were isolated from swab samples from 12% of chilled, eviscerated turkey carcasses, 27% of finished products, and 24% of processing equipment. The same serotypes as those found throughout a plant on any one visit were recovered from 31% of rinse-samples taken from hands and gloves of processing personnel. Salmonellae were found in samples taken on 37 of 48 visits; a greater number of recoveries were made on days when freshly killed turkeys were processed (87%) than when frozen-defrosted carcasses were processed (59%). The predominant serotype isolated from meat and environment usually changed from visit to visit. Salmonella sandiego and Salmonella anatum were the most frequent among 23 serotypes recovered. Most of the isolated serotypes are commonly associated with turkeys and have been incriminated as causative agents of human salmonellosis. The implication is that further-processed turkey products, if inadequately cooked by the consumer and if improperly refrigerated between the time of manufacture and consumption, could directly transmit salmonellae. These same products might also contaminate other foods by introducing salmonellae into food-preparation areas. PMID:5688832

Comparing validation of four ELISA-systems for detection of Salmonella derby- and Salmonella infantis-infected pigs.

PubMed

Roesler, Uwe; Szabo, Istvan; Matthies, Claudia; Albrecht, Kerstin; Leffler, Martin; Scherer, Kathrin; Nöckler, Karsten; Lehmann, Jörg; Methner, Ulrich; Hensel, Andreas; Truyen, Uwe

2011-01-01

The objective of this study was the comparative evaluation of four indirect Salmonella ELISA tests at study time approved in Germany to detect Salmonella infection in pigs.Three tests are based on a LPS-antigen mix and directed against specific IgG antibodies. The fourth test is based on a purified S. Typhimurium whole-cell lysate antigen and discriminates between Salmonella-specific IgM-, IgA-, and IgG- antibodies. In a longitudinal study, two groups of six weeks old hybrid piglets were orally infected with a porcine S. Infantis or S. Derby strain. Clinical and bacteriological parameters were monitored weekly during an observation period of 130 days after infection and serum samples were investigated in parallel with the respective ELISAs. Apparently, the LPS-based ELISA systems used in this study failed to recognize S. Infantis-infected pigs although those animals shed the pathogen in high amounts throughout the study until day 81 post infection (p. i.). In contrast, the isotype-specific Salmonella Typhimurium whole-cell-lysate based ELISA was capable of detecting Salmonella-infected pigs from day ten p. i. at all tested serotypes and revealed the highest sensitivity in detection of S. Infantis-infected pigs. Furthermore, it became apparent that the often used surveillance cut-off value of 40 OD% is not appropriate for intra-vitam detection of S. Infantis- and S. Derby-infected pigs. In contrast, the cut-off values of the ELISAs given by the suppliers result in considerable higher detection rates.

Screening for Salmonella in backyard chickens.

PubMed

Manning, Johanna; Gole, Vaibhav; Chousalkar, Kapil

2015-06-15

Salmonellosis is a significant zoonotic disease which has a considerable economic impact on the egg layer industry. There is limited information about the prevalence of Salmonella spp. in backyard chickens. The current study was conducted to determine the prevalence of Salmonella in backyard chickens, and the associated virulence of any serovars identified. Hundred and fifteen pooled samples from 30 backyard flocks in South Australia were screened. Four flocks tested positive for Salmonella spp. The overall Salmonella isolation rate in the current study was 10.4%. The estimated prevalence at individual bird level was 0.02% (95% CI 0.025-0.975). The serovars isolated were Salmonella Agona, Salmonella subsp 2 ser 21:z10:z6 (Wandsbek) and Salmonella Bovismorbificans. All Salmonella isolates tested positive for the prgH, orfL and spiC genes. The Salmonella subsp 2 ser 21:z10:z6 (Wandsbek) had the most antibiotic resistance, being resistant to ampicillin and cephalothin and having intermediate resistance to florphenicol. All of the Salmonella Agona had intermediate resistance to the ampicillin, while the Salmonella Bovismorbificans were susceptible to all antibiotics tested. With the increased interest of keeping backyard chickens, the current study highlights the zoonotic risk from Salmonella spp. associated with home flocks. Crown Copyright © 2015. Published by Elsevier B.V. All rights reserved.

A simplified experimental model for clearance of some pathogenic bacteria using common bacterivorous ciliated spp. in Tigris river

NASA Astrophysics Data System (ADS)

Ali, Talib Hassan; Saleh, Dhuha Saad

2014-03-01

Bacteria-specific uptake rates of three different protozoan taxa on a pure and mixed bacterial community was studied by means of a simplified and functionally reproducible experimental model. The bacterial species Shigella flexneri, Escherichia coli and Salmonella typhi were isolated and classified from stool samples of patients suffering from diarrhea. Paramecium caudatum, Tetrahymena pyriformis and Halteria grandinella, free living ciliate Protozoans, were isolated and identified from Tigris river water. Pure and mixed ( E. coli + S. typhi), ( E. coli + Sh. flexneri) bacterial cultures were used with each ciliate genera to evaluate the following: predator duplication rate, prey reduction rate, clearance rate and net grazing rate. We used selective lactose fermentation phenomena of enteric bacteria on MacConkey medium for the quantification of bacteria cultural characteristics. The final bacteria concentration was reduced by growing protozoa of 98-99.9 % compared to protozoa-free controls. It showed that Tetrahymena pyriformis had the highest duplication rate (4.13 time/day) in both types of cultures (pure and mixed), followed by Paramecium caudatum and Halteria grandinella, respectively. Paramecium caudatum had the highest rate of ingestion in both types of cultures (26 × 103 bacteria/organism/hr) and yielded the longest time required for 90 % bacterial reduction in a pure suspension of S. typhi (166 h). Clearance rates of pathogenic bacteria by ciliates ranged between 106 nanoliter/organism/h by P. caudatum to S. typhi and 1.92 nanoliter/organism/h seen in T. pyriformis in ( E. coli + S. typhi) mixed culture. We used aquatic experimental microcosms under controlled conditions to explore bacteria-dependent ciliate growth and examined whether these ciliates could discriminate between equally sized bacterial preys in a mixture.

Development and Evaluation of a Multiplex Real-Time Polymerase Chain Reaction Procedure to Clinically Type Prevalent Salmonella enterica Serovars

PubMed Central

Muñoz, Nélida; Diaz-Osorio, Miguel; Moreno, Jaime; Sánchez-Jiménez, Miryan; Cardona-Castro, Nora

2010-01-01

A multiplex real-time polymerase chain reaction procedure was developed to identify the most prevalent clinical isolates of Salmonella enterica subsp. enterica. Genes from the rfb, fliC, fljB, and viaB groups that encode the O, H, and Vi antigens were used to design 15 primer pairs and TaqMan probes specific for the genes rfbJ, wzx, fliC, fljB, wcdB, the sdf-l sequence, and invA, which was used as an internal amplification control. The primers and probes were variously combined into six sets. The first round of reactions used two of these sets to detect Salmonella O:4, O:9, O:7, O:8, and O:3,10 serogroups. Once the serogroups were identified, the results of a second round of reactions that used primers and probes for the flagellar antigen l genes, 1,2; e,h; g,m; d; e,n,x; and z10, and the Vi gene were used to identify individual serovars. The procedure was standardized using 18 Salmonella reference strains and other enterobacteria. The procedure's reliability and sensitivity was evaluated using 267 randomly chosen serotyped Salmonella clinical isolates. The procedure had a sensitivity of 95.5% and was 100% specific. Thus, our technique is a quick, sensitive, reliable, and specific means of identifying S. enterica serovars and can be used in conjunction with traditional serotyping. Other primer and probe combinations could be used to increase the number of identifiable serovars. PMID:20110454

Growth of Salmonella on chilled meat.

PubMed Central

Mackey, B. M.; Roberts, T. A.; Mansfield, J.; Farkas, G.

1980-01-01

Growth rates of a mixture of Salmonella serotypes inoculated on beef from a commercial abattoir were measured at chill temperatures. The minimum recorded mean generation times were 8.1 h at 10 degrees C; 5.2 h at 12.5 degrees C and 2.9 h at 15 degrees C. Growth did not occur at 7-8 degrees C. From these data the maximum extent of growth of Salmonella during storage of meat for different times at chill temperatures was calculated. Criteria for deciding safe handling temperatures for meat are discussed. Maintaining an internal temperature below 10 degrees C during the boning operation would be sufficient to safeguard public health requirements. PMID:7052227

Seroepidemiologic survey of Orientia tsutsugamushi, Rickettsia typhi, and TT118 spotted fever group rickettsiae in rubber estate workers in Malaysia.

PubMed

Tee, T S; Kamalanathan, M; Suan, K A; Chun, S S; Ming, H T; Yasin, R M; Devi, S

1999-07-01

The seroprevalence of Orientia tsutsugamushi, Rickettsia typhi, and TT118 spotted fever group (SFG) rickettsiae in 300 rubber estate workers in Slim River, Malaysia was determined in December 1996 and March 1997. In December, which was the wet season, 23.3%, 3.0%, and 57.3% of the population had antibodies detected against the three rickettsiae, respectively. The highest seropositive rate of 40% was detected for single infection with SFG rickettsiae, followed by a rate of 15.3% for both O. tsutsugamushi and SFG rickettsiae among the rubber estate workers. Subjects less than 21 years old had a lower seroprevalence of SFG rickettsiae compared with the other age groups. Indians had a higher seroprevalence of O. tsutsugamushi compared with other ethnic groups. Rubber tappers had a higher seroprevalence of SFG rickettsiae compared with other occupational groups. During the dry season in March 1997, there was a significant increase in the seroprevalence of R. typhi. The seroconversion rates for IgM against O. tsutsugamushi, R. typhi, and SFG rickettsiae were 5.7%, 12.3%, and 15.1%, respectively, during the four-month period. Significant variations of antibody titers towards the three rickettsiae was noted among subjects who were bled twice. This suggests a significant and continual exposure of rubber estate workers to the three rickettsiae.

Simultaneous, specific and real-time detection of biothreat and frequently encountered food-borne pathogens

PubMed Central

Woubit, Abdela Salah; Yehualaeshet, Teshome; Habtemariam, Tsegaye; Samuel, Temesgen

2012-01-01

The bacterial genera Escherichia, Salmonella, Shigella, Vibrio, Yersinia and Francisella include important food safety and biothreat agents causing food-related and other human illnesses worldwide. We aimed to develop rapid methods with the capability to simultaneously and differentially detect all six pathogens in one run. Our initial experiments to use previously reported sets of primers revealed non-specificity of some of the sequences when tested against a broader array of pathogens, or proved not optimal for simultaneous detection parameters. By extensive mining of the whole genome and protein databases of diverse closely and distantly related bacterial species and strains, we have identified unique genome regions, which we utilized to develop a detection platform. Twelve of the specific genomic targets we have identified to design the primers in F. tularensis ssp. tularensis, F. tularensis ssp. novicida, S. dysentriae, S. typhimurium, V. cholera, Y. pestis, and Y. pseudotuberculosis contained either hypothetical or putative proteins, the functions of which have not been clearly defined. Corresponding primer sets were designed from the target regions for use in real-time PCR assays to detect specific biothreat pathogens at species or strain levels. The primer sets were first tested by in-silico PCR against whole genome sequences of different species, sub-species, or strains and then by in vitro PCR against genomic DNA preparations from 23 strains representing six biothreat agents (E.coli O157:H7 strain EDL 933, Shigella dysentriae, Salmonella typhi, Francisella tularensis ssp. tularensis, Vibrio cholera, and Yersinia pestis) and six foodborne pathogens (Salmonella typhimurium, Salmonella saintpaul, Shigella sonnei, Francisella novicida, Vibrio parahemolytica and Yersinia pseudotuberculosis). Each pathogen was specifically identifiable at the genus and species levels. Sensitivity assays performed using purified DNA showed the lowest detection limit of 640 fg

Development of a novel hexa-plex PCR method for identification and serotyping of Salmonella species.

PubMed

Li, Ruichao; Wang, Yang; Shen, Jianzhong; Wu, Congming

2014-01-01

Salmonella is one of the most important foodborne pathogens, which causes a huge economic burden worldwide. To detect Salmonella rapidly is very meaningful in preventing salmonellosis and decreasing economic losses. Currently, isolation of Salmonella is confirmed by biochemical and serobased serotyping methods, which are time consuming, labor intensive, and complicated. To solve this problem, a hexa-plex polymerase chain reaction (PCR) method was developed using comparative genomics analysis and multiplex PCR technology to detect Salmonella and Salmonella Typhimurium, Salmonella Enteritidis, Salmonella Agona, Salmonella Choleraesuis, and Salmonella Pullorum simultaneously. The accuracy of this method was tested by a collection of 142 Salmonella. Furthermore, the strategy described in this article to mine serovar-specific fragments for Salmonella could be used to find specific fragments for other Salmonella serotypes and bacteria. The combination of this strategy and multiplex PCR is promising in the rapid identification of foodborne pathogens.

Oral immunisation of laying hens with the live vaccine strains of TAD Salmonella vac E and TAD Salmonella vac T reduces internal egg contamination with Salmonella Enteritidis.

PubMed

Gantois, Inne; Ducatelle, Richard; Timbermont, Leen; Boyen, Filip; Bohez, Lotte; Haesebrouck, Freddy; Pasmans, Frank; van Immerseel, Filip

2006-09-11

Eggs are a major source of human infections with Salmonella. Therefore controlling egg contamination in laying hen flocks is one of the main targets for control programmes. A study was carried out to assess the effect of oral vaccination with TAD Salmonella vac E, TAD Salmonella vac T and with both vaccines TAD Salmonella vac E and TAD Salmonella vac T, on colonization of the reproductive tract and internal egg contamination of laying hens with Salmonella Enteritidis. Three groups of 30 laying hens were vaccinated at 1 day, 6 weeks and 16 weeks of age with either one of the vaccine strains, or a combination of both vaccine strains, while a fourth group was left unvaccinated. At 24 weeks of age, the birds were intravenously challenged with 0.5 ml containing 5 x 10(7)cfu Salmonella Enteritidis PT4 S1400/94. The number of oviducts from which Salmonella was isolated, was significantly lower in the vaccinated than in the non-vaccinated hens at 3 weeks post-challenge. Significantly less egg contents were Salmonella positive in the birds vaccinated with TAD Salmonella vac E or TAD Salmonella vac T (12/105 batches of eggs in both groups) than in the unvaccinated birds (28/105 batches of eggs). Internal egg contamination in the hens vaccinated with both TAD Salmonella vac E and TAD Salmonella vac T was even more reduced, as over the whole experiment, only one batch of eggs was positive. In conclusion, these data indicate that vaccination of laying hens with these live vaccines could be considered as a valuable tool in controlling internal egg contamination.

Proteomic Investigation of the Time Course Responses of RAW 264.7 Macrophages to Infection with Salmonella enterica

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shi, Liang; Chowdhury, Saiful M.; Smallwood, Heather S.

2009-08-01

Macrophages plan important roles in controlling Salmonella-mediated systemic infection. To investigate the responses of macrophages to Salmonella infection, we infected RAW 264.7 macrophages with Salmonella enterica serovar Typhimurium (STM) and then performed a comparative liquid chromatography-tandem mass spectrometry [LC-MS(/MS)]-based proteomics analysis of the infected macrophages. A total of 1006 macrophage and 115 STM proteins were indentified from this study. Most of STM proteins were found at late stage of the time course of infection, consistent with the fact that STM proliferates inside RAW 264.7 macrophages. Majority of the identified macrophage proteins were house keeping-related, including cytoplasmic superoxide dismutase 1 (SOD1),more » whose peptide abundances were relatively constant during the time course of infection. Compared to those in no infection control, the peptide abundances of 244 macrophage proteins (or 24% of total indentified macrophage proteins) changed considerably after STM infection. The functions of these STM infection-affected macrophage proteins were diverse and ranged from production of antibacterial nitric oxide (i.e., inducible nitric oxide synthase or iNOS) or production of prostaglandin H2 (i.e., prostaglandin-endoperoxide synthase 2, also know as cyclooxygenase-2 or COX-2) to regulation of intracellular traffic (e.g., sorting nexin or SNX 5, 6 and 9), demonstrating a global impact of STM infection on macrophage proteome. Western-blot analysis not only confirmed the LC-MS(/MS) results of SOD1, COX-2 and iNOS, but also revealed that the protein abundances of mitochondrial SOD2 increased after STM infection, indicating an infection-induced oxidative stress in mitochondria.« less

Immune Reaction and Survivability of Salmonella Typhimurium and Salmonella Infantis after Infection of Primary Avian Macrophages

PubMed Central

Braukmann, Maria; Methner, Ulrich; Berndt, Angela

2015-01-01

Salmonella serovars are differentially able to infect chickens. The underlying causes are not yet fully understood. Aim of the present study was to elucidate the importance of Salmonella Pathogenicity Island 1 and 2 (SPI-1 and -2) for the virulence of two non-host-specific, but in-vivo differently invasive, Salmonella serovars in conjunction with the immune reaction of the host. Primary avian splenic macrophages were inoculated with Salmonella enterica sub-species enterica serovar (S.) Typhimurium and S. Infantis. The number and viability of intracellular bacteria and transcription of SPI-1 and -2 genes by the pathogens, as well as transcription of immune-related proteins, surface antigen expression and nitric oxide production by the macrophages, were compared at different times post inoculation. After infection, both of the Salmonella serovars were found inside the primary macrophages. Invasion-associated SPI-1 genes were significantly higher transcribed in S. Infantis- than S. Typhimurium-infected macrophages. The macrophages counteracted the S. Infantis and S. Typhimurium infection with elevated mRNA expression of inducible nitric oxide synthase (iNOS), interleukin (IL)-12, IL-18 and lipopolysaccharide-induced tumor necrosis factor alpha factor (LITAF) as well as with an increased synthesis of nitric oxide. Despite these host cell attacks, S. Typhimurium was better able than S. Infantis to survive within the macrophages and transcribed higher rates of the SPI-2 genes spiC, ssaV, sifA, and sseA. The results showed similar immune reactions of primary macrophages after infection with both of the Salmonella strains. The more rapid and stronger transcription of SPI-2-related genes by intracellular S. Typhimurium compared to S. Infantis might be responsible for its better survival in avian primary macrophages. PMID:25811871

Enteric Fever in a Tertiary Paediatric Hospital: A Retrospective Six-Year Review.

PubMed

Ahmad Hatib, Nur Adila; Chong, Chia Yin; Thoon, Koh Cheng; Tee, Nancy Ws; Krishnamoorthy, Subramania S; Tan, Natalie Wh

2016-07-01

Enteric fever is a multisystemic infection which largely affects children. This study aimed to analyse the epidemiology, clinical presentation, treatment and outcome of paediatric enteric fever in Singapore. A retrospective review of children diagnosed with enteric fever in a tertiary paediatric hospital in Singapore was conducted from January 2006 to January 2012. Patients with positive blood cultures for Salmonella typhi or paratyphi were identified from the microbiology laboratory information system. Data was extracted from their case records. Of 50 enteric fever cases, 86% were due to Salmonella typhi, with 16.3% being multidrug resistant (MDR) strains. Sixty-two percent of S. typhi isolates were of decreased ciprofloxacin susceptibility (DCS). Five cases were both MDR and DCS. The remaining 14% were Salmonella paratyphi A. There were only 3 indigenous cases. Ninety-four percent had travelled to typhoid-endemic countries, 70.2% to the Indian subcontinent and the rest to Indonesia and Malaysia. All patients infected with MDR strains had travelled to the Indian subcontinent. Anaemia was a significant finding in children with typhoid, as compared to paratyphoid fever (P = 0.04). Although all children were previously well, 14% suffered severe complications including shock, pericardial effusion and enterocolitis. None had typhoid vaccination prior to their travel to developing countries. Enteric fever is largely an imported disease in Singapore and has contributed to significant morbidity in children. The use of typhoid vaccine, as well as education on food and water hygiene to children travelling to developing countries, needs to be emphasised.

Development of a quantitative fluorescence single primer isothermal amplification-based method for the detection of Salmonella.

PubMed

Wang, Jianchang; Li, Rui; Hu, Lianxia; Sun, Xiaoxia; Wang, Jinfeng; Li, Jing

2016-02-16

Food-borne disease caused by Salmonella has long been, and continues to be, an important global public health problem, necessitating rapid and accurate detection of Salmonella in food. Real time PCR is the most recently developed approach for Salmonella detection. Single primer isothermal amplification (SPIA), a novel gene amplification technique, has emerged as an attractive microbiological testing method. SPIA is performed under a constant temperature, eliminating the need for an expensive thermo-cycler. In addition, SPIA reactions can be accomplished in 30 min, faster than real time PCR that usually takes over 2h. We developed a quantitative fluorescence SPIA-based method for the detection of Salmonella. Using Salmonella Typhimurium genomic DNA as template and a primer targeting Salmonella invA gene, we showed the detection limit of SPIA was 2.0 × 10(1)fg DNA. Its successful amplification of different serotypic Salmonella genomic DNA but not non-Salmonella bacterial DNA demonstrated the specificity of SPIA. Furthermore, this method was validated with artificially contaminated beef. In conclusion, we showed high sensitivity and specificity of SPIA in the detection of Salmonella, comparable to real time PCR. In addition, SPIA is faster and more cost-effective (non-use of expensive cyclers), making it a potential alternative for field detection of Salmonella in resource-limited settings that are commonly encountered in developing countries. Copyright © 2015 Elsevier B.V. All rights reserved.

Recombinant plasmid-based quantitative Real-Time PCR analysis of Salmonella enterica serotypes and its application to milk samples.

PubMed

Gokduman, Kurtulus; Avsaroglu, M Dilek; Cakiris, Aris; Ustek, Duran; Gurakan, G Candan

2016-03-01

The aim of the current study was to develop, a new, rapid, sensitive and quantitative Salmonella detection method using a Real-Time PCR technique based on an inexpensive, easy to produce, convenient and standardized recombinant plasmid positive control. To achieve this, two recombinant plasmids were constructed as reference molecules by cloning the two most commonly used Salmonella-specific target gene regions, invA and ttrRSBC. The more rapid detection enabled by the developed method (21 h) compared to the traditional culture method (90 h) allows the quantitative evaluation of Salmonella (quantification limits of 10(1)CFU/ml and 10(0)CFU/ml for the invA target and the ttrRSBC target, respectively), as illustrated using milk samples. Three advantages illustrated by the current study demonstrate the potential of the newly developed method to be used in routine analyses in the medical, veterinary, food and water/environmental sectors: I--The method provides fast analyses including the simultaneous detection and determination of correct pathogen counts; II--The method is applicable to challenging samples, such as milk; III--The method's positive controls (recombinant plasmids) are reproducible in large quantities without the need to construct new calibration curves. Copyright © 2016 Elsevier B.V. All rights reserved.

Design of a Comprehensive Biochemistry and Molecular Biology Experiment: Phase Variation Caused by Recombinational Regulation of Bacterial Gene Expression

ERIC Educational Resources Information Center

Sheng, Xiumei; Xu, Shungao; Lu, Renyun; Isaac, Dadzie; Zhang, Xueyi; Zhang, Haifang; Wang, Huifang; Qiao, Zheng; Huang, Xinxiang

2014-01-01

Scientific experiments are indispensable parts of Biochemistry and Molecular Biology. In this study, a comprehensive Biochemistry and Molecular Biology experiment about "Salmonella enterica" serovar Typhi Flagellar phase variation has been designed. It consisted of three parts, namely, inducement of bacterial Flagellar phase variation,…

78 FR 9399 - Government-Owned Inventions; Availability for Licensing

Federal Register 2010, 2011, 2012, 2013, 2014

2013-02-08

... introduced into the licensed typhoid vaccine strain, Salmonella enterica serovar Typhi strain Ty21a, and was... combination typhoid-shigellosis oral vaccine. For collaboration opportunities, please contact Dr. Dennis J... gene region into a bacterial chromosome. Bacillary dysentery and enteric fevers continue to be...

Survival of Salmonella Copenhagen in food bowls following contamination with experimentally inoculated raw meat: Effects of time, cleaning, and disinfection

PubMed Central

Weese, J Scott; Rousseau, J.

2006-01-01

There are concerns regarding the safety of feeding raw meat to household pets. This study demonstrated that Salmonella persists in food bowls that are inoculated with Salmonella-containing raw meat. Standard methods of cleaning and disinfection were minimally effective at eliminating Salmonella contamination. PMID:17017654

Heatwaves differentially affect risk of Salmonella serotypes.

PubMed

Milazzo, Adriana; Giles, Lynne C; Zhang, Ying; Koehler, Ann P; Hiller, Janet E; Bi, Peng

2016-09-01

Given increasing frequency of heatwaves and growing public health concerns associated with foodborne disease, we examined the relationship between heatwaves and salmonellosis in Adelaide, Australia. Poisson regression analysis with Generalised Estimating Equations was used to estimate the effect of heatwaves and the impact of intensity, duration and timing on salmonellosis and specific serotypes notified from 1990 to 2012. Distributed lag non-linear models were applied to assess the non-linear and delayed effects of temperature during heatwaves on Salmonella cases. Salmonella typhimurium PT135 notifications were sensitive to the effects of heatwaves with a twofold (IRR 2.08, 95% CI 1.14-3.79) increase in cases relative to non-heatwave days. Heatwave intensity had a significant effect on daily counts of overall salmonellosis with a 34% increase in risk of infection (IRR 1.34, 95% CI 1.01-1.78) at >41 °C. The effects of temperature during heatwaves on Salmonella cases and serotypes were found at lags of up to 14 days. This study confirms heatwaves have a significant effect on Salmonella cases, and for the first time, identifies its impact on specific serotypes and phage types. These findings will contribute to the understanding of the impact of heatwaves on salmonellosis and provide insights that could mitigate their impact. Copyright © 2016 The British Infection Association. Published by Elsevier Ltd. All rights reserved.

Salmonella epidemiology: A whirlwind of change.

PubMed

Besser, John M

2018-05-01

The field of infectious disease epidemiology for Salmonella and other enteric pathogens is undergoing some of the most profound changes since the time of Kauffman and White. Rapid advances in "big data" technologies such as genomics and metagenomics are making it possible to monitor and control salmonellosis in new and exciting ways. Epidemiological methods are becoming increasingly robust through the routine use of standardized hypothesis-generating questionnaires, iterative open-ended interviewing, informational trace-backs and new modeling techniques for describing the attribution of disease to food sources. In addition, Salmonella epidemiology is facing important challenges and new opportunities due to the rapid adoption of culture independent diagnostic test panels by clinical laboratories. Where is this unprecedented wave of change taking us? This chapter will examine emerging trends in Salmonella epidemiology, and take a peek into the not-so-distant future. Published by Elsevier Ltd.

Preexisting Salmonella-specific immunity interferes with the subsequent development of immune responses against the Salmonella strains delivering H9N2 hemagglutinin.

PubMed

Hajam, Irshad Ahmed; Lee, John Hwa

2017-06-01

Recombinant Salmonella strains expressing foreign heterologous antigens have been extensively studied as promising live vaccine delivery vehicles. In this study, we constructed attenuated smooth (S-HA) and rough (R-HA) Salmonella strains expressing hemagglutinin (HA) of H9N2, a low pathogenic avian influenza A virus. We then investigated the HA-specific immune responses following oral immunization with either S-HA or R-HA strain in chicken model. We further examined the effects of the preexisting anti-Salmonella immunity on the subsequent elicitation of the HA and the Salmonella ompA specific immune responses. Our results showed that primary immunization with either the S-HA or the R-HA strain elicited comparable HA-specific immune responses and the responses were significantly (p<0.05) higher compared to the Salmonella vector control. When chickens were pre-immunized with the smooth Salmonella carrier alone and then vaccinated with either S-HA or R-HA strain 3, 6 and 9 weeks later, respectively, significant reductions were seen for HA-specific immune responses at week 6, a point which corresponded to the peak of the primary Salmonella-specific antibody responses. No reductions were seen at week 3 and 9, albeit, the HA-specific immune responses were boosted at week 9, a point which corresponded to the lowest primary Salmonella-specific antibody responses. The ompA recall responses remain refractory at week 3 and 6 following deliberate immunization with the carrier strain, but were significantly (p<0.05) increased at week 9 post-primary immunization. We conclude that preexisting anti-Salmonella immunity inhibits antigen-specific immune responses and this effect could be avoided by carefully selecting the time point when carrier-specific immune responses are relatively low. Copyright © 2017 Elsevier B.V. All rights reserved.

Pathogenesis of Salmonellosis: Salmonella Exotoxins

DTIC Science & Technology

1982-03-08

Newport; Sal. 9633 - serotype Newport; and Sal. 9186 - serotype Newport. Salmonella enteritidis serotype typhimurium strain 2000 was obtained from...7054 Table 1I CULTURE MEDIA SURVEY Salmonella enteritidis Salmonella typhimurium serotype Javiana #10016 SRlI Culture Media C H 0 Cell Factor C H 0 Cell...C r AD REPORT NUMBER 2 0 Pathogenesis of Salmonellosis: Salmonella Exotoxins Annual Progress Report (9/1/78-9/1/79) Johnny W. Peterson, Ph.D. March 8

A multiplex real-time PCR assay for the identification and differentiation of Salmonella enterica serovar Typhimurium and monophasic serovar 4,[5],12:i:-.

PubMed

Prendergast, Deirdre M; Hand, Darren; Nί Ghallchóir, Eadaoin; McCabe, Evonne; Fanning, Seamus; Griffin, Margaret; Egan, John; Gutierrez, Montserrat

2013-08-16

Salmonella enterica subsp. enterica serovar 4,[5],12:i:- is considered to be a monophasic variant of Salmonella Typhimurium and is increasingly associated with human infections. The use of PCR for the unequivocal identification of strains identified by conventional serotyping as 4,[5],12:i:- has been recommended by the European Food Safety Authority (EFSA), in particular the conventional multiplex PCR developed by Tennant et al. (2010). An alternative protocol for the identification and differentiation of S. Typhimurium and S. Typhimurium-like strains, including its monophasic variants, based on a multiplex real-time PCR assay was developed in our laboratory. A panel of 206 Salmonella strains was used to validate our multiplex real-time PCR against the conventional multiplex PCR recommended by EFSA, i.e. 43 Salmonella strains of serovars other than Typhimurium and 163 routine isolates determined by slide agglutination serotyping to have an incomplete antigenic formula compatible with the S. Typhimurium formula 4,[5],12:i:1,2. Both methods correctly identified the 43 Salmonella strains as non S. Typhimurium. Among the 163 isolates of undetermined serovar by conventional serotyping, both PCR protocols identified 54 isolates as S. Typhimurium, 101 as monophasic S. Typhimurium and 8 as non-S. Typhimurium. Twenty isolates phenotypically lacking the phase-2 H antigen were positive for the fljB.1,2 gene. These strains have been recently described in the literature by other workers and have been referred to as "inconsistent" variants of S. Typhimurium. Antimicrobial resistance and phage typing were also performed on the S. Typhimurium isolates, including monophasic variants, and approximately half of the isolates identified as monophasic S. Typhimurium by our multiplex real-time PCR protocol were DT193 with the resistance pattern ASSuT. There was 100% concordance between the conventional PCR and the multiplex real-time PCR method developed in this study which proved that

Validation of time and temperature values as critical limits for Salmonella and background flora growth during the production of fresh ground and boneless pork products.

PubMed

Mann, J E; Smith, L; Brashears, M M

2004-07-01

To provide pork processors with valuable data to validate the critical limits set for temperature during pork fabrication and grinding, a study was conducted to determine the growth of Salmonella serotypes and background flora at various temperatures. Growth of Salmonella Typhimurium and Salmonella Enteritidis and of background flora was monitored in ground pork and boneless pork chops held at various temperatures to determine growth patterns. Case-ready modified atmosphere packaged ground pork and fresh whole pork loins were obtained locally. Boneless chops and ground pork were inoculated with a cocktail mixture of streptomycin-resistant Salmonella to facilitate recovery in the presence of background flora. Samples were held at 4.4, 7.2C, and 10 degrees C and at room temperature (22.2 to 23.3 degrees C) to mimic typical processing and holding temperatures observed in pork processing environments. Salmonella counts were determined at regular intervals over 12 and 72 h for both room and refrigeration temperatures. No significant growth of Salmonella (P < 0.05) was observed in boneless pork chops held at refrigeration temperatures. However, Salmonella in boneless pork chops held at room temperature had grown significantly by 8 h. Salmonella grew at faster rates in ground pork. Significant growth was observed at 6, 24. and 72 h when samples were held at room temperature, 10 degrees C, and 7.2 degrees C, respectively. No significant growth was observed at 4.4 degrees C. Background flora in ground pork samples increased significantly after 10 h at room temperature and after 12 h for samples held at 10 and 7.2 degrees C. Background flora in samples held at refrigeration temperatures did not increase until 72 h. Background flora in the boneless chops increased significantly after 6 h at room temperature and after 24 h when held at 10 and 4.4 degrees C. These results illustrate that meat processors can utilize a variety of time and temperature combinations as critical

Salmonella, including antibiotic-resistant Salmonella, from flies captured from cattle farms in Georgia, U.S.A.

PubMed

Xu, Yumin; Tao, Sha; Hinkle, Nancy; Harrison, Mark; Chen, Jinru

2018-03-01

Flies can be transmission vehicles of Salmonella from cattle to humans. This study determined the prevalence of Salmonella in/on flies captured from 33 cattle farms, including 5 beef and 28 dairy farms, in Georgia, USA, and characterized antibiotic resistance profiles of the isolated Salmonella. Twenty-six out of the 33 cattle farms (79%) and 185 out of the 1650 flies (11%) tested positive for Salmonella in the study. The incidence of Salmonella-positive flies varied from farm to farm, ranging from 0 to 78%. Among the 185 Salmonella isolated from flies, 29% were resistant to ampicillin, 28% to tetracycline, 21% to amoxicillin/clavulanic acid, 20% to cefoxitin, and 12% to streptomycin. Incidences of resistance against other tested antibiotics were low, ranging from 0 to 3%. Furthermore, 28% of the Salmonella isolates were multidrug resistant, demonstrating resistance to 3 or more antibiotics. The minimal inhibitory concentrations of ampicillin, cefoxitin, streptomycin, and tetracycline against the Salmonella isolates ranged from 32 to >2048, 64 to 2048, 128 to 1024, and 32 to 1024μg/mL, respectively. These data suggest that flies could be effective vehicles of transmitting antibiotic resistant Salmonella and disseminating antibiotic resistance genes on cattle farms, posing risks to human and animal health. Copyright © 2017 Elsevier B.V. All rights reserved.

Effect of farm type on within-herd Salmonella prevalence, serovar distribution, and antimicrobial resistance.

PubMed

Rasschaert, G; Michiels, J; Arijs, D; Wildemauwe, C; De Smet, S; Heyndrickx, M

2012-05-01

Salmonella represents a major challenge to the pig industry, as pork presents a risk for human salmonellosis. In this study, we have examined the effect of farm type on the prevalence of fattening pigs shedding Salmonella on 12 farms at risk for harboring Salmonella. On six open (grow-to-finish) and six closed (farrow-to-finish) farms, the prevalence of pigs shedding Salmonella was determined on two occasions approximately 2 months apart. The serovar, phage type, and antimicrobial resistance of the obtained Salmonella isolates were determined. On all farms, pigs shedding Salmonella were detected on at least one of the two sampling days. The mean within-herd prevalence was 7.8%. Closed farms were two times less likely to have pigs shedding Salmonella than open farms. On open farms, the odds of finding Salmonella shedding in pigs were 1.9 times higher when sampling was performed at slaughter age than when samples were taken halfway through the fattening period. Salmonella enterica serovar Typhimurium was the most predominant serotype, with a prevalence of 62 to 63% on both farm types. Of all the Salmonella Typhimurium isolates, 65% had the tetraresistant profile ASSuT (ampicillin, streptomycin, sulfonamide, and tetracycline) with or without additional resistance to trimethoprim-sulfonamide. Phage type DT120 seemed to be especially associated with this antimicrobial-resistant profile. The prevalence of Salmonella Typhimurium isolates showing resistance to ampicillin, streptomycin, tetracycline, sulfonamide, trimethoprim-sulfonamide, and lincomycin hydrochloride and spectinomycin sulfate tetrahydrate was significantly higher on open farms than on closed farms.

Dynamics of Salmonella Shedding and Welfare of Hens in Free-Range Egg Production Systems

PubMed Central

Gole, Vaibhav C.; Woodhouse, Rebecca; Caraguel, Charles; Moyle, Talia; Rault, Jean-Loup; Sexton, Margaret

2016-01-01

ABSTRACT The current study investigated the effect of environmental stressors (i.e., weather changes) on Salmonella shedding in free-range production systems and the correlations with behavioral and physiological measures (i.e., fecal glucocorticoid metabolites). This involved longitudinal and point-in-time surveys of Salmonella shedding and environmental contamination on four commercial free-range layer farms. The shedding of Salmonella was variable across free-range farms and in different seasons. There was no significant effect of season on the Salmonella prevalence during this investigation. In this study, the combined Salmonella most probable number (MPN) counts in environmental (including feces, egg belt, dust, nest box, and ramp) samples were highest in samples collected during the summer season (4th sampling, performed in February). The predominant serovars isolated during this study were Salmonella enterica serovar Mbandaka and Salmonella enterica serovar Typhimurium phage types 135 and 135a. These two phage types were involved in several egg product-related Salmonella outbreaks in humans. Multilocus variable-number tandem-repeat analysis (MLVA) results indicated that MLVA types detected from human food poisoning cases exhibited MLVA patterns similar to the strains isolated during this study. All Salmonella isolates (n = 209) were tested for 15 different genes involved in adhesion, invasion, and survival of Salmonella spp. We also observed variations for sopA, ironA, and misL. There were no positive correlations between fecal corticosterone metabolite (FCM) and Salmonella prevalence and/or shedding in feces. Also, there were no positive correlations between Salmonella prevalence and Salmonella count (log MPN) and any of the other welfare parameters. IMPORTANCE In this study, the welfare of laying hens and Salmonella shedding were compared over a prolonged period of time in field conditions. This study investigated the long-term shedding of Salmonella

Dynamics of Salmonella Shedding and Welfare of Hens in Free-Range Egg Production Systems.

PubMed

Gole, Vaibhav C; Woodhouse, Rebecca; Caraguel, Charles; Moyle, Talia; Rault, Jean-Loup; Sexton, Margaret; Chousalkar, Kapil

2017-03-01

The current study investigated the effect of environmental stressors (i.e., weather changes) on Salmonella shedding in free-range production systems and the correlations with behavioral and physiological measures (i.e., fecal glucocorticoid metabolites). This involved longitudinal and point-in-time surveys of Salmonella shedding and environmental contamination on four commercial free-range layer farms. The shedding of Salmonella was variable across free-range farms and in different seasons. There was no significant effect of season on the Salmonella prevalence during this investigation. In this study, the combined Salmonella most probable number (MPN) counts in environmental (including feces, egg belt, dust, nest box, and ramp) samples were highest in samples collected during the summer season (4th sampling, performed in February). The predominant serovars isolated during this study were Salmonella enterica serovar Mbandaka and Salmonella enterica serovar Typhimurium phage types 135 and 135a. These two phage types were involved in several egg product-related Salmonella outbreaks in humans. Multilocus variable-number tandem-repeat analysis (MLVA) results indicated that MLVA types detected from human food poisoning cases exhibited MLVA patterns similar to the strains isolated during this study. All Salmonella isolates ( n = 209) were tested for 15 different genes involved in adhesion, invasion, and survival of Salmonella spp. We also observed variations for sopA , ironA , and misL There were no positive correlations between fecal corticosterone metabolite (FCM) and Salmonella prevalence and/or shedding in feces. Also, there were no positive correlations between Salmonella prevalence and Salmonella count (log MPN) and any of the other welfare parameters. IMPORTANCE In this study, the welfare of laying hens and Salmonella shedding were compared over a prolonged period of time in field conditions. This study investigated the long-term shedding of Salmonella serovars in

Surveillance of Salmonella prevalence in animal feeds and characterization of the Salmonella isolates by serotyping and antimicrobial susceptibility.

PubMed

Li, X; Bethune, L A; Jia, Y; Lovell, R A; Proescholdt, T A; Benz, S A; Schell, T C; Kaplan, G; McChesney, D G

2012-08-01

This article presents the surveillance data from the Feed Contaminants Program (2002-2009) and Salmonella Assignment (2007-2009) of the U.S. Food and Drug Administration (FDA), which monitor the trend of Salmonella contamination in animal feeds. A total of 2,058 samples were collected from complete animal feeds, feed ingredients, pet foods, pet treats, and supplements for pets in 2002-2009. These samples were tested for the presence of Salmonella. Those that were positive for Salmonella underwent serotyping and testing for antimicrobial susceptibility. Of the 2,058 samples, 257 were positive for Salmonella (12.5%). The results indicate a significant overall Salmonella reduction (p≤0.05) in animal feeds from 18.2% (187 samples tested) in 2002 to 8.0% (584 samples tested) in 2009. Among these samples, feed ingredients and pet foods/treats had the most significant reduction (p≤0.05). Of the 45 Salmonella serotypes identified, Salmonella Senftenberg and Salmonella Montevideo were the top two common serotypes (8.9%). Of the 257 Salmonella isolates obtained, 54 isolates (21%) were resistant to at least one antimicrobial. The findings provide the animal feed industries with Salmonella prevalence information that can be used to address Salmonella contamination problems. Our findings can also be used to educate pet owners when handling pet foods and treats at home to prevent salmonellosis.

Market setting and time of purchase influences on salmonella and listeria prevalence in beef and pork in Vietnam

USDA-ARS?s Scientific Manuscript database

This objective of this study was to determine the influence of market type and sampling time on Salmonella and Listeria prevalence of 360 beef (n = 180) and pork (n = 180) samples collected in 6 supermarkets (SM), 6 indoor markets (IM), and 6 open markets (OM) at the opening (T0) and 4 h after the o...