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1.
Vaccine ; 2024 Jul 10.
Article in English | MEDLINE | ID: mdl-38991917

ABSTRACT

BACKGROUND: In 2019, following a large outbreak of typhoid fever, the Zimbabwe Ministry of Health and Child Care conducted a typhoid conjugate vaccine (TCV) vaccination campaign in nine high-risk suburbs of Harare. We aimed to evaluate TCV vaccination coverage, vaccine perceptions, and adverse events reported after vaccination. METHODS: We conducted a two-stage cluster survey to estimate vaccination coverage in the campaign target areas among children aged 6 months-15 years and to classify coverage as either adequate (≥75 % coverage) or inadequate (<75 % coverage) among adults aged 16-45 years in one suburb. Questionnaires assessed socio-demographic factors, TCV vaccination history, reasons for receiving or not receiving TCV, adverse events following immunization, and knowledge and attitudes regarding typhoid and TCV. RESULTS: A total of 1,917 children from 951 households and 298 adults from 135 households enrolled in the survey. Weighted TCV coverage among all children aged 6 months-15 years was 85.3 % (95 % CI: 82.1 %-88.0 %); coverage was 74.8 % (95 % CI: 69.4 %-79.5 %) among children aged 6 months-4 years and 89.3 % (95 % CI: 86.2 %-91.7 %) among children aged 5-15 years. Among adults, TCV coverage was classified as inadequate with a 95 % confidence interval of 55.0 %-73.1 %. Among vaccinated persons, the most reported reason for receiving TCV (96 % across all age groups) was protection from typhoid fever; the most common reasons for non-vaccination were not being in Harare during the vaccination campaign and not being aware of the campaign. Adverse events were infrequently reported in all age groups (10 %) and no serious events were reported. CONCLUSIONS: The 2019 TCV campaign achieved high coverage among school-aged children (5-15 years). Strategies to increase vaccination coverage should be explored for younger children as part of Zimbabwe's integration of TCV into the routine immunization program, and for adults during future post-outbreak campaigns.

2.
Pak J Med Sci ; 40(6): 1219-1224, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38952494

ABSTRACT

Objectives: This study aimed to determine the epidemiology, clinical features, and complications of extensively drug-resistant Salmonella typhi (XDR S. typhi) infection in adults. Method: This cross-sectional study enrolled adults with culture-proven XDR S. typhi admitted to Hayatabad Medical Complex, Peshawar from 1st March to 10th September 2022. Their demographic characteristics, clinical features, treatment, and complications were recorded. Results: Out of 84 patients, 68 (80.9%) were male. The mean age of enrolled patients was 25.2 ± 11.3 years. The mean duration of fever at the time of admission was 13.6 ± 8.2 days, respectively. The most common symptom was loose stools (n=25, 29.8%). Most of the patients (n=69, 82.1%) had received empirical treatment before hospitalization. The majority of the patients (n=42, 50%) received meropenem and a combination of meropenem and azithromycin (n=35, 41.7%) during the study. The time to defervescence for both regimens was similar. Five patients (6%) developed complications of enteric fever. There was no mortality among the participants. Conclusions: Diarrhea was the most common associated clinical feature in XDR typhoid fever. Most of the patients received meropenem alone or in combination with azithromycin with a comparable time to defervescence. The majority of the patients recovered uneventfully and there was no mortality among the study participants.

3.
Infect Genet Evol ; 123: 105632, 2024 Jul 02.
Article in English | MEDLINE | ID: mdl-38964564

ABSTRACT

OBJECTIVES: The aim of this study was to understand the status of extensively drug-resistance (XDR) genotype in Salmonella enterica serotype Typhi (S. Typhi) recovered during the pre to post COVID-19 pandemic period using Multiplex PCR. METHODS: A longitudinal descriptive study was carried out during five years. Antibiotic susceptibility testing was performed according to the Clinical Laboratory Standards Institute antimicrobial susceptibility testing guidelines. The identification of S. Typhi, the detection of their high-risk lineages and XDR genotype was done using single nucleotide polymorphism-based multiplex PCR. RESULTS: A total of four hundred nine (n = 409) S. Typhi isolates were recovered during pre to post COVID-19 pandemic period. Among them, 30.81% belonged to the pre COVID-19 period while 69.19% to the post COVID-19 period. Different trends in antibiotic resistance in S. Typhi isolates with high prevalence of XDR-S. Typhi were observed. However, there was comparatively different frequency of their occurrence among the S. Typhi isolates recovered during pre to post COVID-19 pandemic period. Multiplex PCR showed that the majority of S. Typhi isolates were the H58 haplotype or genotype 4.3.1 which contained XDR genotype. CONCLUSIONS: The increasing episodes of XDR-S. Typhi causing typhoid fever in endemic areas is alarming. The antibiotic resistance in food and water borne pathogens greatly contribute to the dissemination of the antimicrobial resistance in pathogenic bacteria, which has now been considered as a global concern.

4.
IJID Reg ; 11: 100368, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38742235

ABSTRACT

Background: Resistant Salmonella infections are a major global public health challenge particularly for multidrug-resistant (MDR) isolates manifesting as bloodstream infections (BSIs). Objectives: To evaluate clinical, phenotypic, and genotypic characteristics of extended-spectrum beta-lactamase (ESBL) producing Salmonella enterica BSIs from Qatar. Methods: Phenotypic ESBL Salmonella enterica from adult patients presenting with positive BSIs were collected between January 2019 to May 2020. Microbiological identification and characterization were performed using standard methods while genetic characteristics were examined through whole genome sequencing studies. Results: Of 151 episodes of Salmonella enterica BSI, 15 (10%) phenotypic ESBL isolates were collected. Recent travel was recorded in most cases (80%) with recent exposure to antimicrobials (27%). High-level resistance to quinolines, aminoglycosides, and cephalosporins was recorded (80-100%) while meropenem, tigecycline and colistin demonstrated universal susceptibility. Genomic evaluation demonstrated dominance of serotype Salmonella Typhi sequence type 1 (93%) while antimicrobial resistance genes revealed dominance of aminoglycoside resistance (100%), qnrS1 quinolones resistance (80%), blaCTX-M-15 ESBLs (86.7%), and paucity of AmpC resistance genes (6.7%). Conclusions: Invasive MDR Salmonella enterica is mainly imported, connected to patients from high prevalent regions with recent travel and antimicrobial use caused by specific resistant clones. In suspected cases of multidrug resistance, carbapenem therapy is recommended.

5.
Cureus ; 16(4): e58240, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38745803

ABSTRACT

BACKGROUND: The surge in antibiotic-resistant Salmonella enterica serotype Typhi strains has led to heightened morbidity, mortality, and treatment expenses. This study aims to assess the resistance patterns of Salmonella Typhi to diverse antibiotics among patients seeking care at a tertiary hospital in Pakistan. METHODS: A database from a tertiary care hospital in Pakistan was reviewed, and data on blood cultures that isolated Salmonella enterica serotype Typhi were collected. Data were collected and analyzed using Microsoft Excel (Microsoft Corporation, USA) and IBM SPSS software (IBM Corp., Armonk, NY). RESULTS: Demographic information of the selected data was retrieved from the hospital database, and the results showed that 63.7% were male, 36.1% were female, and 0.2% were categorized as neutered. Regarding antibiotic resistance, ampicillin exhibited the highest resistance rate (91.50%), while meropenem demonstrated the lowest (3.00%). Antibiotic sensitivity patterns also varied across different age groups, although statistical analysis indicated no significant differences. Significant associations were found between antibiotic resistance and comorbidities, as well as previous antibiotic use. CONCLUSION:  Salmonella enterica serotype Typhi showed a high resistance to ampicillin and fluoroquinolones, such as ciprofloxacin. The emergence of resistance and decreased sensitivity to current first-line antibiotics necessitates a shift towards alternative options, such as third-generation cephalosporins, azithromycin, and newer antibiotics like meropenem.

6.
Front Microbiol ; 15: 1385834, 2024.
Article in English | MEDLINE | ID: mdl-38646637

ABSTRACT

Background: The Vi-diphtheria toxoid typhoid conjugate vaccine (Vi-DT) has shown promising results in preventing typhoid fever in children under 2 years of age. However, a thorough assessment of its safety and immunogenicity is required to inform vaccination strategies. This systematic review and meta-analysis aimed to determine the safety and immunogenicity of Vi-DT in children below 2 years. Methods: We systematically searched multiple databases, including PubMed, Web of Science, and Scopus, for relevant studies published up to September 2023. We included studies reporting on the safety and immunogenicity outcomes of Vi-DT compared to the control or Vi-tetanus toxoid conjugated vaccine (Vi-TT) in children below 2 years. We applied a random-effects model for meta-analysis using RevMan 5.4. We expressed the results as risk ratio (RR) with a 95% confidence interval (95%CI). Results: In this analysis, five studies were selected, encompassing 1,292 children under 2 years who received the Vi-DT vaccine. No significant difference in immediate reactions was observed within 30 min post-vaccination between Vi-DT and control groups (RR: 0.99 [95% CI: 0.19, 5.26]), nor between Vi-DT and Vi-TT groups. For solicited adverse events within 4 weeks, the VI-DT group showed no significant increase in adverse events compared to control (RR: 0.93 [95% CI: 0.78, 1.12]) or Vi-TT (RR: 0.86 [95% CI: 0.69, 1.07]). Similarly, within 7 days post-vaccination, risk ratios indicated no significant differences in adverse events between the groups. The 4-week seroconversion rate was significantly higher in the Vi-DT group compared to the control (RR: 1.99 [95% CI: 1.07, 3.69]), but no difference was found between Vi-DT and Vi-TT. Adverse events associated with typhoid conjugate vaccines were predominantly non-serious, including fever and injection site reactions. Serious adverse events were rare but included conditions like pneumonia and gastroenteritis. Conclusion: This meta-analysis highlights Vi-DT safety and immunogenicity in six to 24-month-old children. The findings support the use of this Vi-DT to expand typhoid vaccination in endemic regions, in line with WHO's strategy.

7.
IDCases ; 36: e01944, 2024.
Article in English | MEDLINE | ID: mdl-38681077

ABSTRACT

Nalidixic acid-resistant Salmonella enterica serotype Typhi is a well-known cause of enteric fever, and its prevalence is increasing worldwide. However, the incidence of enteric fever complicated by non-immune hemolytic anemia without co-existing thalassemia or glucose-6-phosphate dehydrogenase deficiency is rare. In this case report, we present a case of acute non-immune hemolytic anemia in enteric fever caused by nalidixic acid-resistant Salmonella enterica serotype Typhi.

8.
Infect Dis Now ; 54(4): 104919, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38643864

ABSTRACT

OBJECTIVES: Enteric fever carries appreciable morbidity in non-endemic settings, particularly in returned travelers. This study aimed to characterize the healthcare burden of enteric fever in a low-incidence setting and to identify risk factors and opportunities for preventative interventions. METHODS: Analysis of a retrospective case series from a tertiary pediatric center (2015-2019), augmented by public health notification and microbiological laboratory data (2018-2019), from Western Sydney, Australia, a region with frequent travel links to South Asia. RESULTS: Eighty-nine (89) patients were diagnosed with enteric fever, including 43 children with complete demographic and travel data. Enteric fever cases increased over time (by 4.9 % per year) and incidence was three times higher in the pediatric population (<15 years old) compared to adults. Travel to India and visiting friends and relatives (VFR) travel were risk factors. Few children received enteric fever vaccination prior to travel, as pre-travel advice most commonly was not sought. CONCLUSIONS: Children visiting relatives in high-incidence countries are increasingly at risk for enteric fever, particularly when travelling to South Asia. Targeted health advice to travelers visiting friends and relatives is warranted to mitigate the healthcare burden of enteric fever in low-incidence settings.


Subject(s)
Travel , Typhoid Fever , Humans , Incidence , Typhoid Fever/epidemiology , Male , Retrospective Studies , Female , Child , Adolescent , Child, Preschool , Risk Factors , Australia/epidemiology , Adult , Infant , Vaccination , India/epidemiology , Cost of Illness , Young Adult
9.
mBio ; 15(4): e0340323, 2024 Apr 10.
Article in English | MEDLINE | ID: mdl-38501873

ABSTRACT

AB5-type toxins are a diverse family of protein toxins composed of an enzymatic active (A) subunit and a pentameric delivery (B) subunit. Salmonella enterica serovar Typhi's typhoid toxin features two A subunits, CdtB and PltA, in complex with the B subunit PltB. Recently, it was shown that S. Typhi encodes a horizontally acquired B subunit, PltC, that also assembles with PltA/CdtB to produce a second form of typhoid toxin. S. Typhi therefore produces two AB5 toxins with the same A subunits but distinct B subunits, an evolutionary twist that is unique to typhoid toxin. Here, we show that, remarkably, the Salmonella bongori species independently evolved an analogous capacity to produce two typhoid toxins with distinct B subunits. S. bongori's alternate B subunit, PltD, is evolutionarily distant from both PltB and PltC and outcompetes PltB to form the predominant toxin. We show that, surprisingly, S. bongori elicits similar levels of CdtB-mediated intoxication as S. Typhi during infection of cultured human epithelial cells. This toxicity is exclusively due to the PltB toxin, and strains lacking pltD produce increased amounts of PltB toxin and exhibit increased toxicity compared to the wild type, suggesting that the acquisition of the PltD subunit potentially made S. bongori less virulent toward humans. Collectively, this study unveils a striking example of convergent evolution that highlights the importance of the poorly understood "two-toxin" paradigm for typhoid toxin biology and, more broadly, illustrates how the flexibility of A-B interactions has fueled the evolutionary diversification and expansion of AB5-type toxins. IMPORTANCE: Typhoid toxin is an important Salmonella Typhi virulence factor and an attractive target for therapeutic interventions to combat typhoid fever. The recent discovery of a second version of this toxin has substantial implications for understanding S. Typhi pathogenesis and combating typhoid fever. In this study, we discover that a remarkably similar two-toxin paradigm evolved independently in Salmonella bongori, which strongly suggests that this is a critical aspect of typhoid toxin biology. We observe significant parallels between how the two toxins assemble and their capacity to intoxicate host cells during infection in S. Typhi and S. bongori, which provides clues to the biological significance of this unusual toxin arrangement. More broadly, AB5 toxins with diverse activities and mechanisms are essential virulence factors for numerous important bacterial pathogens. This study illustrates the capacity for novel A-B interactions to evolve and thus provides insight into how such a diverse arsenal of toxins might have emerged.


Subject(s)
Bacterial Toxins , Typhoid Fever , Humans , Typhoid Fever/microbiology , Bacterial Toxins/genetics , Bacterial Toxins/metabolism , Salmonella/metabolism , Salmonella typhi/genetics , Virulence Factors/genetics , Virulence Factors/metabolism
10.
Trop Doct ; 54(2): 189-190, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38321775

ABSTRACT

Typhoid fever, also known as enteric fever, is a multisystemic infection primarily caused by Salmonella enterica serotype Typhi, and less commonly by Salmonella enterica serotypes Paratyphi A, B, and C. The classic presentation includes fever, malaise, diffuse abdominal pain, and constipation. If left untreated, typhoid fever can progress to delirium, obtundation, intestinal haemorrhage, bowel perforation, and death within a month of onset. However, the clinical course can deviate from the classic stepladder fever pattern, which now occurs in as few as 12% of cases.1 In this report, we describe an atypical presentation as sensorineural hearing loss in an otherwise healthy young male.


Subject(s)
Hearing Loss, Sensorineural , Intestinal Perforation , Typhoid Fever , Humans , Male , Hearing Loss, Sensorineural/diagnosis , Hearing Loss, Sensorineural/etiology , Salmonella paratyphi A , Salmonella typhi , Typhoid Fever/complications , Typhoid Fever/diagnosis , Typhoid Fever/drug therapy , Young Adult
11.
Euro Surveill ; 29(5)2024 Feb.
Article in English | MEDLINE | ID: mdl-38304948

ABSTRACT

On 6 April 2022, the Public Health Service of Kennemerland, the Netherlands, was notified about an outbreak of fever and abdominal complaints on a retired river cruise ship, used as shelter for asylum seekers. The diagnosis typhoid fever was confirmed on 7 April. An extensive outbreak investigation was performed. Within 47 days, 72 typhoid fever cases were identified among asylum seekers (n = 52) and staff (n = 20), of which 25 were hospitalised. All recovered after treatment. Consumption of food and tap water on the ship was associated with developing typhoid fever. The freshwater and wastewater tanks shared a common wall with severe corrosion and perforations, enabling wastewater to leak into the freshwater tank at high filling levels. Salmonella Typhi was cultured from the wastewater tank, matching the patient isolates. In the freshwater tank, Salmonella species DNA was detected by PCR, suggesting the presence of the bacterium and supporting the conclusion of contaminated freshwater as the probable source of the outbreak. Outbreaks of uncommon infections may occur if persons from endemic countries are accommodated in crowded conditions. Especially when accommodating migrants on ships, strict supervision on water quality and technical installations are indispensable to guarantee the health and safety of the residents.


Subject(s)
Refugees , Typhoid Fever , Humans , Typhoid Fever/diagnosis , Typhoid Fever/epidemiology , Typhoid Fever/microbiology , Ships , Rivers , Netherlands/epidemiology , Wastewater , Salmonella typhi/genetics , Disease Outbreaks
12.
West Afr J Med ; 41(1): 92-96, 2024 Jan 31.
Article in English | MEDLINE | ID: mdl-38412528

ABSTRACT

Typhoid fever is caused by Salmonella typhi and Salmonella paratyphi. It is a disease of developing countries and is seen among people of low socio-economic status. Patients can develop complications like typhoid intestinal perforation which is associated with higher mortality. A 15-year-old female presented to the emergency pediatric unit with fever, abdominal pain and abdominal distension. She was septic, in respiratory distress, and had marked generalized abdominal tenderness with guarding. An assessment of generalized peritonitis secondary to typhoid intestinal perforation was made. She had exploratory laparotomy with intra-operative findings of ileal perforation and gastric perforation. She had repair of the intestinal and gastric perforations. Our patient presented late with concurrent use of NSAIDs and overwhelming sepsis which likely contributed to the gastric perforation as this is not a usual finding in patients with typhoid intestinal perforation. Gastric perforation is an unusual finding in patients with typhoid intestinal perforation. Typhoid fever and its complications can be easily prevented by the provision of safe water, proper facilities for sanitation, and practicing good hygiene.


La fièvre typhoïde est causée par Salmonella typhi et Salmonella paratyphi. C'est une maladie des pays en développement et elle est observée chez les personnes de bas niveau socio-économique. Les patients peuvent développer des complications telles que la perforation intestinale typhoïdique, associée à une mortalité plus élevée. Une adolescente de 15 ans s'est présentée à l'unité de pédiatrie d'urgence avec de la fièvre, des douleurs abdominales et une distension abdominale. Elle était septique, en détresse respiratoire, et présentait une sensibilité abdominale généralisée marquée avec une défense. Une évaluation d'une péritonite généralisée secondaire à une perforation intestinale typhoïdique a été réalisée. Elle a subi une laparotomie exploratrice révélant une perforation iléale et une perforation gastrique. Des réparations ont été effectuées sur les perforations intestinales et gastriques. Notre patiente s'est présentée tardivement avec une utilisation concomitante d'AINS et une septicémie sévère, ce qui a probablement contribué à la perforation gastrique, car cela n'est pas une découverte habituelle chez les patients atteints de perforation intestinale typhoïdique. La perforation gastrique est une découverte inhabituelle chez les patients atteints de perforation intestinale typhoïdique. La fièvre typhoïde et ses complications peuvent être facilement prévenues par la fourniture d'eau potable, d'installations sanitaires adéquates et en pratiquant une bonne hygiène MOTS-CLÉS: fièvre typhoïde, perforation intestinale, perforation gastrique.


Subject(s)
Intestinal Perforation , Typhoid Fever , Female , Humans , Child , Adolescent , Typhoid Fever/complications , Typhoid Fever/diagnosis , Intestinal Perforation/etiology , Intestinal Perforation/surgery , Abdominal Pain/etiology , Fever , Laparotomy/adverse effects
13.
Radiol Case Rep ; 19(4): 1646-1649, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38327558

ABSTRACT

Typhoid fever, caused by Salmonella Typhi, is a severe bacterial infection prevalent in developing countries, and can result in life-threatening complications if untreated. Nutcracker Syndrome is a rare vascular disorder involving compression of the left renal vein between the aorta and the superior mesenteric artery. It can lead to various symptoms and poses diagnostic and management challenges. We present a case study of a patient diagnosed with typhoid fever in a Unit of Critical Emergency Care. Coincidentally, the evaluation through CT-scan revealed the presence of Nutcracker Syndrome. This report underscores the incidental discovery of Nutcracker Syndrome during the assessment of a patient with typhoid fever in a critical emergency care setting.

14.
Article in English | MEDLINE | ID: mdl-38265374

ABSTRACT

BACKGROUND: Typhoid fever poses a significant health challenge in low- and middleincome countries (LMiCs), impacting millions of individuals across various age groups. Its prevalence is particularly pronounced in South Asia. Factors contributing to its transmission in South Asia include rapid unplanned urbanization, urban-rural disparities, provision of poor water and sanitation facilities, and open defecation. The mortality rate of typhoid fever is up to 1%, and those who survive have a protracted period of poor health and carry an enormous financial burden. The treatment is further complicated by the emerging antibiotic resistance leaving few treatment options in hands. This issue has become more urgent due to the further emergence of extended drug-resistant (XDR) and multidrugresistant (MDR) typhoid strains, as well as their subsequent global spread. Fluoroquinoloneresistant Salmonella spp. is currently classified by the World Health Organization (WHO) as a high (Priority 2) pathogen. As a result, establishing minimum inhibitory concentrations (MIC) according to the latest guidelines may prove effective in treating typhoid fever and minimizing the rising threat of drug resistance.

15.
Trop Dis Travel Med Vaccines ; 10(1): 3, 2024 Feb 01.
Article in English | MEDLINE | ID: mdl-38297337

ABSTRACT

BACKGROUND: Typhoid fever is commonly found until today, especially in developing countries. It has fatal complications and measures must be taken to reduce the incidence of typhoid. Vaccinations are a key factor in prevention. This is a phase II randomized observer-blind clinical trial on a novel Vi-DT conjugate vaccine on 200 subjects 12 to 40 years of age. METHODS: Subjects were screened for eligibility after which a blood sample was taken and one dose of vaccine was administered. Investigational vaccine used was Vi-DT and control was Vi-PS. Twenty-eight days after vaccination, subjects visited for providing blood sample to assess immunogenicity and were asked about local and systemic adverse reactions that occurred in the first 28 days. RESULTS: Subjects had minor adverse reactions. Pain was the most common local reaction. Muscle pain was the most common systemic reaction. There were no serious adverse events up to 28 days post vaccination. Seroconversion rates were 100% in the Vi-DT group and 95.96% in the Vi-PS group. Post vaccination GMTs were increased in both groups but it was significantly higher in the Vi-DT group (p < 0.001). CONCLUSIONS: Vi-DT typhoid conjugate vaccine is safe and immunogenic in healthy Indonesian subjects 12 to 40 years. TRIAL REGISTRATION: Approved by ClinicalTrials.gov. CLINICAL TRIAL REGISTRATION NUMBER: NCT03460405. Registered on 09/03/2018. URL: https://clinicaltrials.gov/ct2/show/NCT03460405 .

16.
J Infect Dis ; 229(4): 979-987, 2024 Apr 12.
Article in English | MEDLINE | ID: mdl-37775091

ABSTRACT

BACKGROUND: Environmental surveillance (ES) for Salmonella Typhi potentially offers a low-cost tool to identify communities with a high burden of typhoid fever. METHODS: We developed standardized protocols for typhoid ES, including sampling site selection, validation, characterization; grab or trap sample collection, concentration; and quantitative PCR targeting Salmonella genes (ttr, staG, and tviB) and a marker of human fecal contamination (HF183). ES was implemented over 12 months in a historically high typhoid fever incidence setting (Vellore, India) and a lower incidence setting (Blantyre, Malawi) during 2021-2022. RESULTS: S. Typhi prevalence in ES samples was higher in Vellore compared with Blantyre; 39/520 (7.5%; 95% confidence interval [CI], 4.4%-12.4%) vs 11/533 (2.1%; 95% CI, 1.1%-4.0%) in grab and 79/517 (15.3%; 95% CI, 9.8%-23.0%) vs 23/594 (3.9%; 95% CI, 1.9%-7.9%) in trap samples. Detection was clustered by ES site and correlated with site catchment population in Vellore but not Blantyre. Incidence of culture-confirmed typhoid in local hospitals was low during the study and zero some months in Vellore despite S. Typhi detection in ES. CONCLUSIONS: ES describes the prevalence and distribution of S. Typhi even in the absence of typhoid cases and could inform vaccine introduction. Expanded implementation and comparison with clinical and serological surveillance will further establish its public health utility.


Subject(s)
Typhoid Fever , Typhoid-Paratyphoid Vaccines , Humans , Typhoid Fever/epidemiology , Typhoid Fever/prevention & control , Salmonella typhi/genetics , Malawi/epidemiology , Incidence , India/epidemiology
17.
J Infect Dis ; 2023 Dec 20.
Article in English | MEDLINE | ID: mdl-38123455

ABSTRACT

OBJECTIVES: In Santiago, Chile, where typhoid had been hyperendemic (1977-1991), we investigated whether residual chronic carriers could be detected among household contacts of non-travel-related typhoid cases occurring 2017-2019. METHODS: Culture-confirmed cases were classified as "autochthonous" (domestically-acquired) versus "travel/immigration-related". Household contacts of cases had stool cultures and serum Vi antibody measurements to detect chronic Salmonella Typhi carriers. Whole genome sequences of acute cases and their epidemiologically-linked chronic carrier isolates were compared. RESULTS: Five of 16 autochthonous typhoid cases (31.3%) were linked to four chronic carriers in case households; two cases (onsets 23 months apart) were linked to the same carrier. Carriers were women aged 69-79 years with gallbladder dysfunction and Typhi fecal excretion; three had highly elevated serum anti-Vi titers. Genomic analyses revealed close identity (≤11 core genome SNP [Single Nucleotide Polymorphism] differences) between case and epidemiologically-linked carrier isolates; all were genotypes prevalent in 1980s Santiago. A cluster of four additional autochthonous cases un-linked to a carrier was identified based on genomic identity (0-1 SNPs). Travel/immigration isolate genotypes were typical for the countries of travel/immigration. CONCLUSIONS: Although autochthonous typhoid cases in Santiago are currently rare, 5/16 such cases (31.3%) were linked to elderly chronic carriers identified among household contacts of cases.

18.
Curr Genomics ; 24(2): 100-109, 2023 Oct 27.
Article in English | MEDLINE | ID: mdl-37994324

ABSTRACT

Background: Salmonella typhi biofilm confers a serious public health issue for lengthy periods and the rise in antibiotic resistance and death rate. Biofilm generation has rendered even the most potent antibiotics ineffective in controlling the illness, and the S. typhi outbreak has turned into a fatal disease typhoid. S. typhi infection has also been connected to other deadly illnesses, such as a gall bladder cancer. The virulence of this disease is due to the interaction of numerous genes and proteins of S. typhi. Objective: The study aimed to identify a cascade of target proteins in S. typhi biofilm condition with the help of genomic data mining and protein-protein interaction analysis. Methods: The goal of this study was to notice some important pharmacological targets in S. typhi. using genomic data mining, and protein-protein interaction approaches were used so that new drugs could be developed to combat the disease. Results: In this study, we identified 15 potential target proteins that are critical for S. typhi biofilm growth and maturation. Three proteins, CsgD, AdrA, and BcsA, were deciphered with their significant role in the synthesis of cellulose, a critical component of biofilm's extracellular matrix. The CsgD protein was also shown to have high interconnectedness and strong interactions with other important target proteins of S. typhi. As a result, it has been concluded that CsgD is involved in a range of activities, including cellulose synthesis, bacterial pathogenicity, quorum sensing, and bacterial virulence. Conclusion: All identified targets in this study possess hydrophobic properties, and their cellular localization offered proof of a potent therapeutic target. Overall results of this study, drug target shortage in S. typhi is also spotlighted, and we believe that obtained result could be useful for the design and development of some potent anti-salmonella agents for typhoid fever in the future.

19.
J Pak Med Assoc ; 73(11): 2219-2225, 2023 Nov.
Article in English | MEDLINE | ID: mdl-38013532

ABSTRACT

Numerous infectious diseases, including enteric fever, malaria, dengue fever, and, most recently, coronavirus disease-2019, are prevalent in Pakistan. All these diseases have overlapping clinical symptoms and can present a diagnostic challenge for the general practitioner. Since definitive testing for these disorders is time-consuming and expensive, basic clinical testing, such as a complete blood count, should be utilised to supplement clinical diagnosis, when possible. The current narrative review was planned to present specific alterations in haematological parameters for each of these disorders. The review was intended as a guide for practising physicians in their decision-making.


Subject(s)
Dengue , Malaria , Typhoid Fever , Humans , Pakistan/epidemiology , Endemic Diseases , Dengue/diagnosis , Dengue/epidemiology , Blood Cell Count , Malaria/diagnosis , Malaria/epidemiology , Typhoid Fever/diagnosis , Typhoid Fever/epidemiology
20.
JMIR Public Health Surveill ; 9: e41207, 2023 Nov 20.
Article in English | MEDLINE | ID: mdl-37983081

ABSTRACT

BACKGROUND: Typhoid fever, or enteric fever, is a highly fatal infectious disease that affects over 9 million people worldwide each year, resulting in more than 110,000 deaths. Reduction in the burden of typhoid in low-income countries is crucial for public health and requires the implementation of feasible water, sanitation, and hygiene (WASH) interventions, especially in densely populated urban slums. OBJECTIVE: In this study, conducted in Mirpur, Bangladesh, we aimed to assess the association between household WASH status and typhoid risk in a training subpopulation of a large prospective cohort (n=98,087), and to evaluate the performance of a machine learning algorithm in creating a composite WASH variable. Further, we investigated the protection associated with living in households with improved WASH facilities and in clusters with increasing prevalence of such facilities during a 2-year follow-up period. METHODS: We used a machine learning algorithm to create a dichotomous composite variable ("Better" and "Not Better") based on 3 WASH variables: private toilet facility, safe drinking water source, and presence of water filter. The algorithm was trained using data from the training subpopulation and then validated in a distinct subpopulation (n=65,286) to assess its sensitivity and specificity. Cox regression models were used to evaluate the protective effect of living in "Better" WASH households and in clusters with increasing levels of "Better" WASH prevalence. RESULTS: We found that residence in households with improved WASH facilities was associated with a 38% reduction in typhoid risk (adjusted hazard ratio=0.62, 95% CI 0.49-0.78; P<.001). This reduction was particularly pronounced in individuals younger than 10 years at the first census participation, with an adjusted hazard ratio of 0.49 (95% CI 0.36-0.66; P<.001). Furthermore, we observed an inverse relationship between the prevalence of "Better" WASH facilities in clusters and the incidence of typhoid, although this association was not statistically significant in the multivariable model. Specifically, the adjusted hazard of typhoid decreased by 0.996 (95% CI 0.986-1.006) for each percent increase in the prevalence of "Better" WASH in the cluster (P=.39). CONCLUSIONS: Our findings demonstrate that existing variations in household WASH are associated with differences in the risk of typhoid in densely populated urban slums. This suggests that attainable improvements in WASH facilities can contribute to enhanced typhoid control, especially in settings where major infrastructural improvements are challenging. These findings underscore the importance of implementing and promoting comprehensive WASH interventions in low-income countries as a means to reduce the burden of typhoid and improve public health outcomes in vulnerable populations.


Subject(s)
Typhoid Fever , Water , Humans , Sanitation , Typhoid Fever/epidemiology , Typhoid Fever/prevention & control , Bangladesh/epidemiology , Prospective Studies , Poverty Areas , Hygiene
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