-
Frontiers in Immunology 2019In primary infection with , it has been reported-without consideration of 's functions-that humoral immunity plays no role in the clearance of bacteria. In fact,... (Review)
Review
In primary infection with , it has been reported-without consideration of 's functions-that humoral immunity plays no role in the clearance of bacteria. In fact, targets and suppresses several aspects of humoral immunity, including B cell lymphopoiesis, B cell activation, and IgG production. In particular, the suppression of IgG-secreting plasma cell maintenance allows the persistence of in tissues. Therefore, the critical role(s) of humoral immunity in the response to infection, especially at the late phase, should be re-investigated. The suppression of IgG plasma cell memory strongly hinders vaccine development against non-typhoidal (NTS) because can also reduce humoral immune memory against other bacteria and viruses, obtained from previous vaccination or infection. We propose a new vaccine against that would not impair humoral immunity, and which could also be used as a treatment for antibody-dependent autoimmune diseases to deplete pathogenic long-lived plasma cells, by utilizing the 's own suppression mechanism of humoral immunity.
Topics: Animals; B-Lymphocytes; Host-Pathogen Interactions; Humans; Immunity, Humoral; Plasma Cells; Salmonella; Salmonella Infections
PubMed: 32038650
DOI: 10.3389/fimmu.2019.03155 -
FEMS Microbiology Reviews Jun 2002Strains of Salmonella spp. with resistance to antimicrobial drugs are now widespread in both developed and developing countries. In developed countries it is now... (Review)
Review
Strains of Salmonella spp. with resistance to antimicrobial drugs are now widespread in both developed and developing countries. In developed countries it is now increasingly accepted that for the most part such strains are zoonotic in origin and acquire their resistance in the food-animal host before onward transmission to humans through the food chain. Of particular importance since the early 1990s has been a multiresistant strain of Salmonella typhimurium definitive phage type (DT) 104, displaying resistance to up to six commonly used antimicrobials, with about 15% of isolates also exhibiting decreased susceptibility to ciprofloxacin. Mutations in the gyrA gene in such isolates have been characterised by a PCR LightCycler-based gyrA mutation assay, and at least four different mutations have been identified. Multiple resistance (to four or more antimicrobials) is also common in the poultry-associated pathogens Salmonella virchow and Salmonella hadar, with an increasing number of strains of these serotypes exhibiting decreased susceptibility to ciprofloxacin. Multiple resistance is also being found in other serotypes in several other European countries, and has been associated with treatment failures. For Salmonella typhi, multiple drug resistance is now the norm in strains originating in the Indian subcontinent and south-east Asia. Such multiresistant strains have been responsible for several epidemics and some of these have been associated with contaminated water supplies. Furthermore, an increasing number of multiresistant strains of S. typhi are now exhibiting decreased susceptibility to ciprofloxacin, with concomitant treatment failures. In developed countries antimicrobial resistance in zoonotic salmonellas has been attributed to the injudicious use of antimicrobials in food-producing animals. It is hoped that the application of Codes of Practice for the use of such agents, which have been prepared by the pharmaceutical industry in response to widespread international concern about the development of drug resistance in bacterial pathogens, will now result in a widespread reduction in the incidence of drug-resistant salmonellas in food production animals and humans on an international scale.
Topics: Anti-Infective Agents; Developed Countries; Drug Resistance, Multiple, Bacterial; Fluoroquinolones; Food Microbiology; Humans; Salmonella; Salmonella Infections; Water Microbiology
PubMed: 12069879
DOI: 10.1111/j.1574-6976.2002.tb00606.x -
Frontiers in Cellular and Infection... 2020Within the species of , there is significant diversity represented among the numerous subspecies and serovars. Collectively, these account for microbes with variable... (Review)
Review
Within the species of , there is significant diversity represented among the numerous subspecies and serovars. Collectively, these account for microbes with variable host ranges, from common plant and animal colonizers to extremely pathogenic and human-specific serovars. Despite these differences, many species find commonality in the ability to form biofilms and the ability to cause acute, latent, or chronic disease. The exact outcome of infection depends on many factors such as the growth state of , the environmental conditions encountered at the time of infection, as well as the infected host and immune response elicited. Here, we review the numerous biofilm lifestyles of (on biotic and abiotic surfaces) and how the production of extracellular polymeric substances not only enhances long-term persistence outside the host but also is an essential function in chronic human infections. Furthermore, careful consideration is made for the events during initial infection that allow for gut transcytosis which, in conjunction with host immune functions, often determine the progression of disease. Both typhoidal and non-typhoidal salmonellae can cause chronic and/or secondary infections, thus the adaptive immune responses to both types of bacteria are discussed with particular attention to the differences between Typhi, Typhimurium, and invasive non-typhoidal that can result in differential immune responses. Finally, while strides have been made in our understanding of immunity to in the lymphoid organs, fewer definitive studies exist for intestinal and hepatobiliary immunity. By examining our current knowledge and what remains to be determined, we provide insight into new directions in the field of immunity, particularly as it relates to chronic infection.
Topics: Animals; Biofilms; Humans; Intestines; Salmonella enterica; Salmonella typhi; Salmonella typhimurium
PubMed: 33604308
DOI: 10.3389/fcimb.2020.624622 -
EcoSal Plus Dec 2021The species Salmonella enterica comprises over 2,600 serovars, many of which are known to be intracellular pathogens of mammals, birds, and reptiles. It is now apparent...
The species Salmonella enterica comprises over 2,600 serovars, many of which are known to be intracellular pathogens of mammals, birds, and reptiles. It is now apparent that Salmonella is a highly adapted environmental microbe and can readily persist in a number of environmental niches, including water, soil, and various plant (including produce) species. Much of what is known about the evolution and diversity of nontyphoidal Salmonella serovars (NTS) in the environment is the result of the rise of the genomics era in enteric microbiology. There are over 340,000 Salmonella genomes available in public databases. This extraordinary breadth of genomic diversity now available for the species, coupled with widespread availability and affordability of whole-genome sequencing (WGS) instrumentation, has transformed the way in which we detect, differentiate, and characterize Salmonella enterica strains in a timely way. Not only have WGS data afforded a detailed and global examination of the molecular epidemiological movement of Salmonella from diverse environmental reservoirs into human and animal hosts, but they have also allowed considerable consolidation of the diagnostic effort required to test for various phenotypes important to the characterization of Salmonella. For example, drug resistance, serovar, virulence determinants, and other genome-based attributes can all be discerned using a genome sequence. Finally, genomic analysis, in conjunction with functional and phenotypic approaches, is beginning to provide new insights into the precise adaptive changes that permit persistence of NTS in so many diverse and challenging environmental niches.
Topics: Animals; Food Safety; Genomics; Humans; Phylogeny; Public Health; Salmonella
PubMed: 34125583
DOI: 10.1128/ecosalplus.ESP-0008-2020 -
Epidemics Dec 2022This dose response assessment combines data from 6 human challenge studies and 44 outbreaks to determine infectivity and pathogenicity of several serotypes of nontyphoid...
This dose response assessment combines data from 6 human challenge studies and 44 outbreaks to determine infectivity and pathogenicity of several serotypes of nontyphoid Salmonella. Outcomes focus on the major serotypes Salmonella Enteritidis and Typhimurium, showing that Typhimurium is less infectious and has a lower probability of causing acute illness in infected subjects. The dose response relation of Salmonella Enteritidis is less steep than that of Typhimurium, indicating greater heterogeneity in infectivity and pathogenicity. This study revisits an older study with less flexible methods that could not combine the widely different outcomes of challenge studies and outbreaks, and had limited capability for dealing with missing information. Reported outcomes are in a format that allows use in calculations of uncertainty for quantitative risk assessment.
Topics: Humans; Salmonella typhimurium; Salmonella enteritidis; Serogroup; Virulence; Disease Outbreaks
PubMed: 36436317
DOI: 10.1016/j.epidem.2022.100653 -
Poultry Science Aug 2017Salmonella contamination in chicken samples can cause major health problems in humans. However, not only the effects of antibiotic treatment during growth but also the...
Salmonella contamination in chicken samples can cause major health problems in humans. However, not only the effects of antibiotic treatment during growth but also the impacts of the poultry slaughter line on the prevalence of Salmonellae in final chicken meat sold to consumers are unknown. In this study, we compared the isolation rates and antimicrobial resistance of Salmonellae among antibiotic-free, conventional, conventional Korean native retail chicken meat samples, and clonal divergence of Salmonella isolates by multilocus sequence typing. In addition, the distribution of extended-spectrum β-lactamase (ESBL) genes in ESBL-producing Salmonella isolates was analyzed. A total of 72 retail chicken meat samples (n = 24 antibiotic-free broiler [AFB] chickens, n = 24 conventional broiler [CB] chickens, and n = 24 conventional Korean native [CK] chickens) was collected from local retail markets in Seoul, South Korea. The isolation rates of Salmonellae were 66.6% in AFB chickens, 45.8% in CB chickens, and 25% in CK chickens. By analyzing the minimum inhibitory concentrations of β-lactam antibiotics with the disc-diffusion test, we found that 81.2% of Salmonella isolates from AFB chickens, 63.6% of isolates from CB chickens, and 50% of isolates from CK chickens were ESBL producers; all ESBL-positive isolates had the CTX-M-15 genotype. Interestingly, all ESBL-producing Salmonellae were revealed as ST16 by multilocus sequence typing and had the genetic platform of blaCTX-M gene (IS26-ISEcp1-blaCTX-M-15-IS903), which was first reported in Salmonellae around the world. The Salmonella ST33 strain (S. Hadar) isolated in this study has never been reported in South Korea. In conclusion, our findings showed that antibiotic-free retail chicken meat products were also largely contaminated with ESBL-producing Salmonellae and that their ESBL genes and genetic platforms were the same as those isolated from conventional retail chicken meat products.
Topics: Animal Husbandry; Animals; Anti-Bacterial Agents; Bacterial Proteins; Chickens; Drug Resistance, Bacterial; Food Microbiology; Genes, Bacterial; Meat; Microbial Sensitivity Tests; Organic Agriculture; Prevalence; Republic of Korea; Salmonella; beta-Lactamases
PubMed: 28482031
DOI: 10.3382/ps/pex055 -
FEBS Letters Aug 2020Pathogens that colonize deep tissues and spread systemically encounter the innate host resistance mechanism of complement-mediated lysis and complement opsonization... (Review)
Review
Pathogens that colonize deep tissues and spread systemically encounter the innate host resistance mechanism of complement-mediated lysis and complement opsonization leading to engulfment and degradation by phagocytic cells. Yersinia and Salmonella species have developed numerous strategies to block the antimicrobial effects of complement. These include recruitment of complement regulatory proteins factor H, C4BP, and vitronectin (Vn) as well as interference in late maturation events such as assembly of C9 into the membrane attack complex that leads to bacterial lysis. This review will discuss the contributions of various surface structures (proteins, lipopolysaccharide, and capsules) to evasion of complement-mediated immune clearance of the systemic pathogens Yersiniae and Salmonellae. Bacterial proteins required for recruitment of complement regulatory proteins will be described, including the details of their interaction with host regulatory proteins, where known. The potential role of the surface proteases Pla (Yersinia pestis) and PgtE (Salmonella species) on the activity of complement regulatory proteins will also be addressed. Finally, the implications of complement inactivation on host cell interactions and host cell targeting for type 3 secretion will be discussed.
Topics: Animals; Bacterial Proteins; Complement System Proteins; Humans; Immune Evasion; Plasminogen Activators; Salmonella; Type III Secretion Systems; Yersinia pestis
PubMed: 32170725
DOI: 10.1002/1873-3468.13771 -
Epidemiology and Infection Jun 1988Between 1969 and 1984, 6564 non-typhoid salmonella strains were isolated at the Liverpool Public Health Laboratory of which 194 (3.0%) were from extraintestinal sites....
Between 1969 and 1984, 6564 non-typhoid salmonella strains were isolated at the Liverpool Public Health Laboratory of which 194 (3.0%) were from extraintestinal sites. Blood (34%) and urine (32%) isolates accounted for two-thirds of these, with the remainder being recovered from pus and inflammatory tissue (23%), bone (5%), cerebrospinal fluid (5%) and sputum (3%). Certain serotypes tended to cause more invasive disease than others, i.e. Salmonella choleraesuis, S. dublin, S. london, S. virchow and S. panama: this association for S. london has not previously been described. The spectrum of disease caused by non-typhoid strains was broad. This survey confirms the importance of non-typhoid salmonellas as occasional causes of invasive disease and local sepsis outside the gastrointestinal tract.
Topics: Adolescent; Aged; Blood; Bone and Bones; Cerebrospinal Fluid; Feces; Female; Humans; Infant; Male; Salmonella; Salmonella Infections; Serotyping; Sputum; Suppuration; Urine
PubMed: 3378582
DOI: 10.1017/s095026880006711x -
Veterinary Medicine and Science Mar 2021This study determined the passage time and phage propagation time of salmonella specific phages, Felix O1 and S16, in 10 bearded dragons, based on re-isolation from...
Influence of Salmonella specific bacteriophages (O1; S16) on the shedding of naturally occurring Salmonella and an orally applied Salmonella Eastbourne strain in bearded dragons (Pogona vitticeps).
This study determined the passage time and phage propagation time of salmonella specific phages, Felix O1 and S16, in 10 bearded dragons, based on re-isolation from cloacal swabs and faecal samples following oral administration, as a possible tool for reducing salmonella shedding. In Study 1, Felix O1 was administered orally for 12 consecutive days. Over 60 days, swabs were taken from the oral cavity and cloaca and qualitative Salmonella detection as well as salmonella quantification from faecal samples were performed. In Study 2, a phage cocktail (Felix O1 and S16) was administered to half of the tested animals. Salmonella (S.) Eastbourne was also given orally to all animals. Oral and cloacal swabs were tested as in Study 1, and faecal samples were collected for phage quantification. Various Salmonella serovars were detectable at the beginning of the study. The numbers of serovars detected declined over the course of the study. S. Kisarawe was most commonly detected. Salmonella titres ranged from 10 to 10 cfu/g faeces. The phages (Felix O1 and S16) were detectable for up to 20 days after the last administration. The initial phage titres ranged from 10 to 10 pfu/ml. The study shows that the phages were able to replicate in the intestine, and were shed for a prolonged period and therefore could contribute to a reduction of Salmonella shedding.
Topics: Animals; Bacterial Shedding; Lizards; Salmonella; Salmonella Infections, Animal; Salmonella Phages
PubMed: 33161646
DOI: 10.1002/vms3.388 -
MSystems Jun 2022Salmonella is one of the most successful foodborne pathogens worldwide, owing in part to its ability to colonize or infect a wide range of hosts. Salmonella serovars are... (Review)
Review
Salmonella is one of the most successful foodborne pathogens worldwide, owing in part to its ability to colonize or infect a wide range of hosts. Salmonella serovars are known to encode a variety of different fimbriae (hairlike organelles that facilitate binding to surfaces); however, the distribution, number, and sequence diversity of fimbriae encoded across different lineages of Salmonella were unknown. We queried whole-genome sequence (WGS) data for 242 Salmonella enterica subsp. (subspecies ) isolates from the top 217 serovars associated with isolation from humans and agricultural animals; this effort identified 2,894 chaperone-usher (CU)-type fimbrial usher sequences, representing the most conserved component of CU fimbriae. On average, isolates encoded 12 different CU fimbrial ushers (6 to 18 per genome), although the distribution varied significantly ( = 1.328E-08) by phylogenetic clade, with isolates in section Typhi having significantly fewer fimbrial ushers than isolates in clade A2 (medians = 10 and 12 ushers, respectively). Characterization of fimbriae in additional non- subspecies genomes suggested that 8 fimbrial ushers were classified as being unique to subspecies isolates, suggesting that the majority of fimbriae were most likely acquired prior to the divergence of subspecies . Characterization of mobile elements suggested that plasmids represent an important vehicle facilitating the acquisition of a wide range of fimbrial ushers, particularly for the acquisition of fimbriae from other Gram-negative genera. Overall, our results suggest that differences in the number and type of fimbriae encoded most likely reflect differences in phylogenetic clade rather than differences in host range. Fimbriae of the CU assembly pathway represent important organelles that mediate Salmonella's interactions with host tissues and abiotic surfaces. Our analyses provide a comprehensive overview of the diversity of CU fimbriae in Salmonella spp., highlighting that the majority of CU fimbriae are distributed broadly across multiple subspecies and suggesting that acquisition most likely occurred prior to the divergence of subspecies . Our data also suggest that plasmids represent the primary vehicles facilitating the horizontal transfer of diverse CU fimbriae in Salmonella. Finally, the observed high sequence similarity between some ushers suggests that different names may have been assigned to closely related fimbrial ushers that likely should be represented by a single designation. This highlights the need to establish standard criteria for fimbria classification and nomenclature, which will also facilitate future studies seeking to associate virulence factors with adaptation to or differences in the likelihood of causing disease in a given host.
Topics: Animals; Humans; Phylogeny; Host Specificity; Fimbriae, Bacterial; Salmonella; Salmonella enterica
PubMed: 35467401
DOI: 10.1128/msystems.00115-22