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Journal of Microbiology (Seoul, Korea) Apr 2005Shigellosis is a global human health problem. Four species of Shigella i.e. S. dysenteriae, S. flexneri, S. boydii and S. sonnei are able to cause the disease. These... (Review)
Review
Shigellosis is a global human health problem. Four species of Shigella i.e. S. dysenteriae, S. flexneri, S. boydii and S. sonnei are able to cause the disease. These species are subdivided into serotypes on the basis of O-specific polysaccharide of the LPS. Shigella dysenteriae type 1 produces severe disease and may be associated with life-threatening complications. The symptoms of shigellosis include diarrhoea and/or dysentery with frequent mucoid bloody stools, abdominal cramps and tenesmus. Shigella spp. cause dysentery by invading the colonic mucosa. Shigella bacteria multiply within colonic epithelial cells, cause cell death and spread laterally to infect and kill adjacent epithelial cells, causing mucosal ulceration, inflammation and bleeding. Transmission usually occurs via contaminated food and water or through person-to-person contact. Laboratory diagnosis is made by culturing the stool samples using selective/differential agar media. Shigella spp. are highly fragile organism and considerable care must be exercised in collecting faecal specimens, transporting them to the laboratories and in using appropriate media for isolation. Antimicrobial agents are the mainstay of therapy of all cases of shigellosis. Due to the global emergence of drug resistance, the choice of antimicrobial agents for treating shigellosis is limited. Although single dose of norfloxacin and ciprofloxacin has been shown to be effective, they are currently less effective against S. dysenteriae type 1 infection. Newer quinolones, cephalosporin derivatives, and azithromycin are the drug of choice. However, fluoroquinolone-resistant S. dysenteriae type 1 infection have been reported. Currently, no vaccines against Shigella infection exist. Both live and subunit parenteral vaccine candidates are under development. Because immunity to Shigella is serotype-specific, the priority is to develop vaccine against S. dysenteriae type 1 and S. flexneri type 2a. Shigella species are important pathogens responsible for diarrhoeal diseases and dysentery occurring all over the world. The morbidity and mortality due to shigellosis are especially high among children in developing countries. A recent review of literature (Kotloff et al.,1999) concluded that, of the estimated 165 million cases of Shigella diarrhoea that occur annually, 99% occur in developing countries, and in developing countries 69% of episodes occur in children under five years of age. Moreover, of the ca.1.1 million deaths attributed to Shigella infections in developing countries, 60% of deaths occur in the under-five age group. Travellers from developed to developing regions and soldiers serving under field conditions are also at an increased risk to develop shigellosis.
Topics: Drug Resistance, Bacterial; Dysentery, Bacillary; Humans; Shigella; Shigella Vaccines; Virulence Factors
PubMed: 15880088
DOI: No ID Found -
Brazilian Journal of Microbiology :... 2014Shigellosis produces inflammatory reactions and ulceration on the intestinal epithelium followed by bloody or mucoid diarrhea. It is caused by enteroinvasive E. coli... (Review)
Review
Shigellosis produces inflammatory reactions and ulceration on the intestinal epithelium followed by bloody or mucoid diarrhea. It is caused by enteroinvasive E. coli (EIEC) as well as any species of the genus Shigella, namely, S. dysenteriae, S. flexneri, S. boydii, and S. sonnei. This current species designation of Shigella does not specify genetic similarity. Shigella spp. could be easily differentiated from E. coli, but difficulties observed for the EIEC-Shigella differentiation as both show similar biochemical traits and can cause dysentery using the same mode of invasion. Sequencing of multiple housekeeping genes indicates that Shigella has derived on several different occasions via acquisition of the transferable forms of ancestral virulence plasmids within commensal E. coli and form a Shigella-EIEC pathovar. EIEC showed lower expression of virulence genes compared to Shigella, hence EIEC produce less severe disease than Shigella spp. Conventional microbiological techniques often lead to confusing results concerning the discrimination between EIEC and Shigella spp. The lactose permease gene (lacY) is present in all E. coli strains but absent in Shigella spp., whereas β-glucuronidase gene (uidA) is present in both E. coli and Shigella spp. Thus uidA gene and lacY gene based duplex real-time PCR assay could be used for easy identification and differentiation of Shigella spp. from E. coli and in particular EIEC.
Topics: Bacteriological Techniques; Diagnosis, Differential; Dysentery, Bacillary; Escherichia coli; Genes, Bacterial; Genotype; Molecular Diagnostic Techniques; Multiplex Polymerase Chain Reaction; Real-Time Polymerase Chain Reaction; Shigella; Virulence Factors
PubMed: 25763015
DOI: 10.1590/s1517-83822014000400002 -
Frontiers in Cellular and Infection... 2016Shigella is a pathovar of Escherichia coli comprising four groups, Shigella flexneri, Shigella sonnei, Shigella dysenteriae, and Shigella boydii, each of them, with the... (Review)
Review
Shigella is a pathovar of Escherichia coli comprising four groups, Shigella flexneri, Shigella sonnei, Shigella dysenteriae, and Shigella boydii, each of them, with the exception of S.sonnei, comprising several serotypes. Shigella accounts for the majority of dysentery causing infections occurring world-wide each year. Recent advancements in the Shigella field have led to a better understanding of the molecular mechanisms underlying host epithelial cell invasion and immune cell function manipulation, mainly using S. flexneri as a model. Host-cell invasion is the final step of the infection process, as Shigella's virulence strategy relies also on its ability to survive hostile conditions during its journey through the gastro-intestinal tract, to compete with the host microbiota and to cross the intestinal mucus layer. Hence, the diversity of the virulence strategies among the different Shigella species has not yet been deeply investigated, which might be an important step to understand the epidemiological spreading of Shigella species worldwide and a key aspect for the validation of novel vaccine candidates. The recent development of high-throughput screening and sequencing methods will facilitate these complex comparison studies. In this review we discuss several of the major avenues that the Shigella research field has taken over the past few years and hopefully gain some insights into the questions that remain surrounding this important human pathogen.
Topics: Dysentery, Bacillary; Epithelial Cells; Geography; Host-Pathogen Interactions; Humans; Shigella boydii; Shigella dysenteriae; Shigella flexneri; Shigella sonnei
PubMed: 27148494
DOI: 10.3389/fcimb.2016.00045 -
Frontiers in Cellular and Infection... 2017is the major cause of bacillary dysentery world-wide. It is divided into four species, named , and , which are distinct genomically and in their ability to cause... (Review)
Review
is the major cause of bacillary dysentery world-wide. It is divided into four species, named , and , which are distinct genomically and in their ability to cause disease. Shigellosis, the clinical presentation of infection, is characterized by watery diarrhea, abdominal cramps, and fever. 's ability to cause disease has been attributed to virulence factors, which are encoded on chromosomal pathogenicity islands and the virulence plasmid. However, information on these virulence factors is not often brought together to create a detailed picture of infection, and how this translates into shigellosis symptoms. Firstly, secretes virulence factors that induce severe inflammation and mediate enterotoxic effects on the colon, producing the classic watery diarrhea seen early in infection. Secondly, injects virulence effectors into epithelial cells via its Type III Secretion System to subvert the host cell structure and function. This allows invasion of epithelial cells, establishing a replicative niche, and causes erratic destruction of the colonic epithelium. Thirdly, produces effectors to down-regulate inflammation and the innate immune response. This promotes infection and limits the adaptive immune response, causing the host to remain partially susceptible to re-infection. Combinations of these virulence factors may contribute to the different symptoms and infection capabilities of the diverse species, in addition to distinct transmission patterns. Further investigation of the dominant species causing disease, using whole-genome sequencing and genotyping, will allow comparison and identification of crucial virulence factors and may contribute to the production of a pan- vaccine.
Topics: Adaptive Immunity; Animals; Bacterial Adhesion; Dysentery, Bacillary; Epithelium; Host-Pathogen Interactions; Humans; Immunity, Innate; Immunomodulation; Intestinal Mucosa; Plasmids; Shigella; Type III Secretion Systems; Virulence; Virulence Factors
PubMed: 28393050
DOI: 10.3389/fcimb.2017.00064 -
Travel Medicine and Infectious Disease 2023Southeast Asia is attractive for tourism. Unfortunately, travelers to this region are at risk of becoming infected with Shigella. We conducted a meta-analysis to provide... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Southeast Asia is attractive for tourism. Unfortunately, travelers to this region are at risk of becoming infected with Shigella. We conducted a meta-analysis to provide updates on Shigella prevalence in Southeast Asia, along with their serogroups and serotypes.
METHODS
We conducted a systematic search using PubMed, EMBASE, and Web of Science for peer-reviewed studies from 2000 to November 2022. We selected studies that detected Shigella in stools by culture or polymerase chain reaction (PCR). Two reviewers extracted the data using a standardized form and performed quality assessments using the Joanna Briggs Institute checklist. The random effects model was used to estimate the pooled prevalence of Shigella.
RESULTS
During our search, we identified 4376 studies. 29 studies (from six Southeast Asian countries) were included in the systematic review, 21 each in the meta-analysis of the prevalence of Shigella (Sample size: 109545) and the prevalence of Shigella serogroups. The pooled prevalence of Shigella was 4% (95% CI: 4-5%) among diarrhea cases. Shigella sonnei was the most abundant serogroup in Thailand (74%) and Vietnam (57%), whereas Shigella flexneri was dominant in Indonesia (72%) and Cambodia (71%). Shigella dysenteriae and Shigella boydii were uncommon (pooled prevalence of 1% each). The pooled prevalence of Shigella was 5% (95% CI: 4-6%) in children aged <5 years. The pooled prevalence showed a decreasing trend comparing data collected between 2000-2013 (5%; 95% CI: 4-6%) and between 2014-2022 (3%; 95% CI: 2-4%). Shigella prevalence was 6% in studies that included participants with mixed pathogens versus 3% in those without. Shigella flexneri serotype 2a was the most frequently isolated (33%), followed by 3a (21%), 1b (10%), 2b (3%), and 6 (3%).
CONCLUSIONS
This study provides compelling evidence for the development of effective Shigella vaccines for residents of endemic regions and travellers to these areas.
Topics: Child; Humans; Dysentery, Bacillary; Shigella; Shigella dysenteriae; Shigella flexneri; Indonesia
PubMed: 36792021
DOI: 10.1016/j.tmaid.2023.102554 -
Antibiotics (Basel, Switzerland) Nov 2022Shigellosis remains one of the leading causes of morbidity and mortality worldwide and is the second leading cause of diarrheal mortality among all age groups. However,... (Review)
Review
Shigellosis remains one of the leading causes of morbidity and mortality worldwide and is the second leading cause of diarrheal mortality among all age groups. However, the global emergence of antimicrobial-resistant strains, limiting the choice of effective drugs for shigellosis, has become the major challenge in the treatment of infections. The aim of this systematic review and meta-analysis was to provide an updated picture of the prevalence of antimicrobial-resistant species in Asia. A comprehensive and systematic search was performed on three electronic databases (PubMed, ScienceDirect and Scopus), in which 63 eligible studies published between 2010 and 2022 were identified. From our meta-analysis of proportions using a random-effects model, the overall prevalence of spp. in Asian patients was estimated to be 8.0% (95% CI: 5.5-10.5). The pooled prevalence rates of multidrug-resistant (MDR) and extended-spectrum beta-lactamase (ESBL)-producing strains were 68.7% (95% CI: 59.9-77.5) and 23.9% (95% CI: 12.9-34.8), respectively. Concerning recommended antimicrobial drugs for , the prevalence of resistance was highest for ciprofloxacin (29.8%) and azithromycin (29.2%), followed by ceftriaxone (23.8%), in spite of their importance as first- and second-line treatments for shigellosis. In contrast, resistance to carbapenems, such as ertapenem (0.0%), imipenem (0.1%) and meropenem (0.0%), was almost non-existent among the 49 tested antibiotics. The significantly high prevalence estimation suggests that the multidrug-resistant is a pressing threat to public health worthy of careful and justified interventions. Effective antibiotic treatment strategies, which may lead to better outcomes for the control and treatment of shigellosis in Asia, are essential.
PubMed: 36421297
DOI: 10.3390/antibiotics11111653 -
Virulence Dec 2022Although four species (. , , and ) have been reported, . sp. PAMC 28760, an Antarctica isolate, is the only one with a complete genome deposited in NCBI database as an...
Although four species (. , , and ) have been reported, . sp. PAMC 28760, an Antarctica isolate, is the only one with a complete genome deposited in NCBI database as an uncharacterized isolate. Because it is the world's driest, windiest, and coldest continent, Antarctica provides an unfavourable environment for microorganisms. Computational analysis of genomic sequences of four species and our uncategorized Antarctica isolates sp. PAMC28760 was performed using MP3 (offline version) program to predict trehalase encoding genes as a pathogenic or non-pathogenic form. Additionally, we employed RAST and Prokka (offline version) annotation programs to determine locations of periplasmic () and cytoplasmic () trehalase genes in studied genomes. Our results showed that only 56 out of 134 strains had two different trehalase genes ( and ). It was revealed that the gene tends to be prevalent in species. In addition, both and genes were present in our strain . sp. PAMC28760. The main objective of this study was to predict the prevalence of two different trehalase genes ( and ) in the complete genome of sp. PAMC28760 and other complete genomes of species. Till date, it is the first study to show that two types of trehalase genes are involved in species, which could offer insight on how the bacteria use accessible carbohydrate like glucose produced from the trehalose degradation pathway, and importance of periplasmic trehalase involvement in bacterial virulence.
Topics: Antarctic Regions; Genomics; Shigella; Trehalase
PubMed: 36040103
DOI: 10.1080/21505594.2022.2117679 -
BMC Pediatrics Feb 2020Diarrhea, particularly of enteric bacterial pathogen, remains a major cause of morbidity and mortality in Ethiopia. Despite the high prevalence of diarrheal disease...
BACKGROUND
Diarrhea, particularly of enteric bacterial pathogen, remains a major cause of morbidity and mortality in Ethiopia. Despite the high prevalence of diarrheal disease among under-five children, antibiotic resistance of bacterial pathogens test is not part of routine childcare in the study area. This study aimed to investigate the prevalence and antimicrobial susceptibility status of Salmonella and Shigella species among diarrheic children attending public health institutions in Ambo town, west Showa, Ethiopia.
METHODS
Institutional based, cross-sectional study was carried out from January to July 2014 among 239 diarrheic children below five years of age in Ambo town, Ethiopia. Information about patient demographics, signs, and symptoms was obtained from the parents/guardians of each child using a questionnaire. Stool samples from diarrheic children were collected and processed for isolation of Salmonella and Shigella using conventional microbiology procedures. Suspected Salmonella isolates were confirmed by genus-specific PCR and serotyped using a slide agglutination test. Susceptibility to 10 commonly used antimicrobials was assessed using the Kirby Bauer disc diffusion method.
RESULTS
From the 239 children screened, only nine (3.8%) of them were positive for either Salmonella (n = 3) or Shigella (n = 6) and 19 (7.9%) positive for the intestinal parasite. Three species of Shigella were identified: Shigella flexinari (n = 3), Shigella boydii (n = 2), and Shigella sonnei (n = 1). The three Salmonella isolates were S. chicago, S. caracas, and S. saintpaul. Salmonella and Shigella isolates were resistant to ampicillin (88.9%), followed by tetracycline (66.7%), cotrimoxazole (55.6%), chloramphenicol (44.4%), amoxicillin (33.3%), nalidixic acid (11.1%) and cefotaxime (11.1%). All isolates were sensitive to amikacin, ciprofloxacin, and gentamycin.
CONCLUSION
In this study, either Salmonella or Shigella species were detected only in 3.8% of diarrheic children in Ambo town, suggesting the dominance of other causes of diarrhea in the study area. A further study targeting other causes of diarrhea should be conducted to establish the major causes of childhood diarrhea in the study area.
Topics: Animals; Anti-Bacterial Agents; Anti-Infective Agents; Child; Cross-Sectional Studies; Diarrhea; Ethiopia; Feces; Female; Humans; Male; Microbial Sensitivity Tests; Prevalence; Salmonella; Shigella
PubMed: 32103729
DOI: 10.1186/s12887-020-1970-0 -
The Pan African Medical Journal 2022Salmonella and Shigella infections are waterborne associated infections globally known to cause serious illnesses in all age groups, but can be more devastating in...
INTRODUCTION
Salmonella and Shigella infections are waterborne associated infections globally known to cause serious illnesses in all age groups, but can be more devastating in children below five years. Antimicrobial resistance has been known to worsen the existing challenge in the management of Salmonella and Shigella infections. The aim is to isolate and identify Salmonella and Shigella among children less than five years with diarrhea and to determine resistance to commonly prescribed drugs at the Lodwar County and Referral Hospital in Northern Kenya.
METHODS
using a cross-sectional study design, a descriptive experimental study was conducted on 196 children with diarrhea using rectal swabs. A structured questionnaire was used to collect sociodemographic information. Samples were then received in the microbiology laboratory, and macroscopic and microscopic examinations were done before culture on specific selective media. Thereafter, biochemical confirmation of the growths done then confirmed results tabulated before analysis.
RESULTS
from the total samples collected (196) Shigella dysenteriae cases were 4 (5%), while Shigella Flexneri were 7 (9%), Shigella sonnei were 3 (4%), Shigella boydii were 4 (5%) and Salmonella typhimurium were 2 (2.4%). From these, about 70% of the isolated Salmonella and Shigella demonstrated high antibiotic resistance to Amoxilliclav and Ampicillin, both with high minimum inhibitory concentrations (MICs) values of about 8ug/ml. While over 80% drug susceptibility was noted in Amikacin (1ug/ml), Ciprofloxacin (2ug/ml), Ceftriaxone (4ug/ml) and Ceftazidime (4ug/ml).
CONCLUSION
Salmonella and Shigella are among the common contributors of diarrhea among children less than five years. Drug resistance among the commonly used antibiotics is a serious indicator that possible misuse of antibiotics especially the beta lactam penicillin's.
Topics: Anti-Bacterial Agents; Child; Child, Preschool; Cross-Sectional Studies; Diarrhea; Drug Resistance, Bacterial; Dysentery, Bacillary; Feces; Humans; Kenya; Microbial Sensitivity Tests; Prevalence; Salmonella; Shigella
PubMed: 35812262
DOI: 10.11604/pamj.2022.42.13.32025 -
Frontiers in Microbiology 2023and enterotoxigenic (ETEC) are major bacterial pathogens of diarrheal disease that is the second leading cause of childhood mortality globally. Currently, it is well...
and enterotoxigenic (ETEC) are major bacterial pathogens of diarrheal disease that is the second leading cause of childhood mortality globally. Currently, it is well known that spp., and . are very closely related with many common characteristics. Evolutionarily speaking, spp., are positioned within the phylogenetic tree of . . Therefore, discrimination of spp., from . is very difficult. Many methods have been developed with the aim of differentiating the two species, which include but not limited to biochemical tests, nucleic acids amplification, and mass spectrometry, etc. However, these methods suffer from high false positive rates and complicated operation procedures, which requires the development of novel methods for accurate and rapid identification of spp., and . . As a low-cost and non-invasive method, surface enhanced Raman spectroscopy (SERS) is currently under intensive study for its diagnostic potential in bacterial pathogens, which is worthy of further investigation for its application in bacterial discrimination. In this study, we focused on clinically isolated . strains and species (spp.), that is, . , . , . , and . , based on which SERS spectra were generated and characteristic peaks for spp., and . were identified, revealing unique molecular components in the two bacterial groups. Further comparative analysis of machine learning algorithms showed that, the Convolutional Neural Network (CNN) achieved the best performance and robustness in bacterial discrimination capacity when compared with Random Forest (RF) and Support Vector Machine (SVM) algorithms. Taken together, this study confirmed that SERS paired with machine learning could achieve high accuracy in discriminating spp., from . , which facilitated its application potential for diarrheal prevention and control in clinical settings. Graphical abstract.
PubMed: 36970678
DOI: 10.3389/fmicb.2023.1101357