Reduction of mortality in chloramphenicol-treated severe typhoid fever by high-dose dexamethasone

Asymptomatic Salmonella Myocarditis: A Case Report of a Rare Entity

Enteric fever typically displays symptoms like high fever, abdominal pain, constipation, and headaches, primarily affecting the digestive system. While it is commonly seen as a gastrointestinal infection, it can also lead to rare but significant cardiovascular issues. There have been only a few reported cases of enteric fever causing heart manifestations. We present a case of a young male with enteric fever-induced myocarditis, which, due to its rarity, can be challenging to diagnose and is essentially a diagnosis of exclusion. Cardiac MRI (CMR) is crucial for diagnosis, supported by ECG, echocardiograms, and troponin levels. The treatment involves standard approaches for cardiomyopathy, including angiotensin-converting enzyme (ACE) inhibitors, beta-blockers, and diuretics. However, our patient presented as a case of asymptomatic myocarditis and fully recovered with treatment without any long-lasting heart problems. Our study aims to contribute to the limited body of knowledge on heart-related complications of enteric fever, raising awareness among clinicians of such presentations in enteric fever cases.

Typhoid fever

Typhoid fever is an invasive bacterial disease associated with bloodstream infection that causes a high burden of disease in Africa and Asia. Typhoid primarily affects individuals ranging from infants through to young adults. The causative organism, Salmonella enterica subsp. enterica serovar Typhi is transmitted via the faecal-oral route, crossing the intestinal epithelium and disseminating to systemic and intracellular sites, causing an undifferentiated febrile illness. Blood culture remains the practical reference standard for diagnosis of typhoid fever, where culture testing is available, but novel diagnostic modalities are an important priority under investigation. Since 2017, remarkable progress has been made in defining the global burden of both typhoid fever and antimicrobial resistance; in understanding disease pathogenesis and immunological protection through the use of controlled human infection; and in advancing effective vaccination programmes through strategic multipartner collaboration and targeted clinical trials in multiple high-incidence priority settings. This Primer thus offers a timely update of progress and perspective on future priorities for the global scientific community.

Milan's forgotten epidemic of summer 1629, a few months before the last great plague: An investigation into the possible cause

An epidemic not attributable to plague caused thousands of deaths in Milan in the summer of 1629, a time of war and famine that immediately preceded the even more fatal Great Plague of 1630 that killed an estimated ten of thousands of people. The 5,993 deaths of 1629 recorded in the Liber Mortuorum of Milan (a city with an estimated population of 130,000 inhabitants at the time) were 45.7% more than the average number recorded between 1601 and 1628. Registered deaths peaked in July, and 3,363 of the deaths (56,1%) were attributed to a febrile illness which, in most cases (2,964, 88%), was not associated with a rash or organ involvement. These deaths involved 1,627 males and 1,334 females and occurred at a median age of 40 years (range 0-95). In this paper, we discuss the possible cause of the epidemic, which may have been an outbreak of typhoid fever.

Triple immune modulator therapy for aberrant hyperinflammatory responses in severe COVID-19

A dysregulated hyperinflammatory response is a key pathogenesis of severe COVID-19, but optimal immune modulator treatment has not been established. To evaluate the clinical effectiveness of double (glucocorticoids and tocilizumab) and triple (plus baricitinib) immune modulator therapy for severe COVID-19, a retrospective cohort study was conducted. For the immunologic investigation, a single-cell RNA sequencing analysis was performed in serially collected PBMCs and neutrophil specimens. Triple immune modulator therapy was a significant factor in a multivariable analysis for 30-day recovery. In the scRNA-seq analysis, type I and II IFN response-related pathways were suppressed by GC, and the IL-6-associated signature was additionally downregulated by TOC. Adding BAR to GC and TOC distinctly downregulated the ISGF3 cluster. Adding BAR also regulated the pathologically activated monocyte and neutrophil subpopulation induced by aberrant IFN signals. Triple immune modulator therapy in severe COVID-19 improved 30-day recovery through additional regulation of the aberrant hyperinflammatory immune response.

British Infection Association Guidelines for the Diagnosis and Management of Enteric Fever in England

Enteric fever (EF) is an infection caused by the bacteria called Salmonella Typhi or Paratyphi. Infection is acquired through swallowing contaminated food or water. Most EF in England occurs in people returning from South Asia and other places where EF is common; catching EF in England is rare. The main symptom is fever, but stomach pain, diarrhoea, muscle aches, rash and other symptoms may occur. EF is diagnosed by culturing the bacteria from blood and/or stool in a microbiology laboratory. EF usually responds well to antibiotic treatment. Depending on how unwell the individual is, antibiotics may be administered by mouth or by injection. Over the past several years, there has been an overall increase in resistance to antibiotics used to treat enteric fever, in all endemic areas. Additionally, since 2016, there has been an ongoing outbreak of drug-resistant EF in Pakistan. This infection is called extensively drug-resistant, or XDR, EF and only responds to a limited number of antibiotics. Occasionally individuals develop complications of EF including confusion, bleeding, a hole in the gut or an infection of the bones or elsewhere. Some people may continue to carry the bacteria in their stool for a longtime following treatment for the initial illness. These people may need treatment with a longer course of antibiotics to eradicate infection. Travellers can reduce their risk of acquiring EF by following safe food and water practices and by receiving the vaccine at least a few weeks before travel. These guidelines aim to help doctors do the correct tests and treat patients for enteric fever in England but may also be useful to doctors and public health professionals in other similar countries.

Acute sensorineural hearing loss as atypical presentation of typhoid fever in adult patient

Salmonella Typhi is the main cause of an acute febrile, sometimes fatal, multisystemic illness called typhoid fever. The diverse presentations of this disease make it a diagnostic challenge in some patients. Involvement of the neurological system, including cochleovestibular system, is very rare with less than a handful of reported cases. This case report describes the condition of a previously healthy 23-year-old Pakistani man with acute onset of hearing loss associated with fever, headache, and disorientation. The most likely differential diagnoses were bacterial or viral meningoencephalitis, and other bacterial infections, such as Rickettsial and spirochetal diseases. Salmonella Typhi grew on blood culture; thus, treatment with intravenous antibiotics and systemic steroids was provided with excellent response. Hearing loss gradually improved and almost completely resolved within 3 to 4 weeks.

Selenium Deficiency Is Associated with Mortality Risk from COVID-19

SARS-CoV-2 infections underlie the current coronavirus disease (COVID-19) pandemic and are causative for a high death toll particularly among elderly subjects and those with comorbidities. Selenium (Se) is an essential trace element of high importance for human health and particularly for a well-balanced immune response. The mortality risk from a severe disease like sepsis or polytrauma is inversely related to Se status. We hypothesized that this relation also applies to COVID-19. Serum samples (n = 166) from COVID-19 patients (n = 33) were collected consecutively and analyzed for total Se by X-ray fluorescence and selenoprotein P (SELENOP) by a validated ELISA. Both biomarkers showed the expected strong correlation (r = 0.7758, p < 0.001), pointing to an insufficient Se availability for optimal selenoprotein expression. In comparison with reference data from a European cross-sectional analysis (EPIC, n = 1915), the patients showed a pronounced deficit in total serum Se (mean ± SD, 50.8 ± 15.7 vs. 84.4 ± 23.4 µg/L) and SELENOP (3.0 ± 1.4 vs. 4.3 ± 1.0 mg/L) concentrations. A Se status below the 2.5th percentile of the reference population, i.e., [Se] < 45.7 µg/L and [SELENOP] < 2.56 mg/L, was present in 43.4% and 39.2% of COVID samples, respectively. The Se status was significantly higher in samples from surviving COVID patients as compared with non-survivors (Se; 53.3 ± 16.2 vs. 40.8 ± 8.1 µg/L, SELENOP; 3.3 ± 1.3 vs. 2.1 ± 0.9 mg/L), recovering with time in survivors while remaining low or even declining in non-survivors. We conclude that Se status analysis in COVID patients provides diagnostic information. However, causality remains unknown due to the observational nature of this study. Nevertheless, the findings strengthen the notion of a relevant role of Se for COVID convalescence and support the discussion on adjuvant Se supplementation in severely diseased and Se-deficient patients.

Selenium Deficiency Is Associated with Mortality Risk from COVID-19

SARS-CoV-2 infections underlie the current coronavirus disease (COVID-19) pandemic and are causative for a high death toll particularly among elderly subjects and those with comorbidities. Selenium (Se) is an essential trace element of high importance for human health and particularly for a well-balanced immune response. The mortality risk from a severe disease like sepsis or polytrauma is inversely related to Se status. We hypothesized that this relation also applies to COVID-19. Serum samples (n = 166) from COVID-19 patients (n = 33) were collected consecutively and analyzed for total Se by X-ray fluorescence and selenoprotein P (SELENOP) by a validated ELISA. Both biomarkers showed the expected strong correlation (r = 0.7758, p < 0.001), pointing to an insufficient Se availability for optimal selenoprotein expression. In comparison with reference data from a European cross-sectional analysis (EPIC, n = 1915), the patients showed a pronounced deficit in total serum Se (mean ± SD, 50.8 ± 15.7 vs. 84.4 ± 23.4 µg/L) and SELENOP (3.0 ± 1.4 vs. 4.3 ± 1.0 mg/L) concentrations. A Se status below the 2.5th percentile of the reference population, i.e., [Se] < 45.7 µg/L and [SELENOP] < 2.56 mg/L, was present in 43.4% and 39.2% of COVID samples, respectively. The Se status was significantly higher in samples from surviving COVID patients as compared with non-survivors (Se; 53.3 ± 16.2 vs. 40.8 ± 8.1 µg/L, SELENOP; 3.3 ± 1.3 vs. 2.1 ± 0.9 mg/L), recovering with time in survivors while remaining low or even declining in non-survivors. We conclude that Se status analysis in COVID patients provides diagnostic information. However, causality remains unknown due to the observational nature of this study. Nevertheless, the findings strengthen the notion of a relevant role of Se for COVID convalescence and support the discussion on adjuvant Se supplementation in severely diseased and Se-deficient patients.

Management of Travel-Related Infectious Diseases in the Emergency Department

Purpose of Review

Emergency physicians generally have limited exposure to internationally acquired illnesses. However, travelers can present quite ill, and delays in recognition and treatment can lead to increased morbidity and mortality. This paper aims to summarize typical presentations of common international diseases and provide the emergency physician with a practical approach based on current guidelines.

Recent Findings

In the treatment of traveler’s diarrhea, azithromycin has become the treatment of choice due to the growing antibiotic resistance. Intravenous artesunate was approved in 2019 under investigational new drug protocol for the treatment of severe malaria, and artemisinin-based combination therapies (ACTs) have become the first-line treatment for most cases of uncomplicated malaria. Since the 2015 outbreak, Zika has become a concern to many travelers, but the current treatment is supportive.

Summary

Clinicians should be aware of a few noteworthy updates in the treatment of internationally acquired illnesses, but more importantly, they must recognize warning signs of severe illness and treat promptly. Future research on workup and disposition could help emergency physicians identify which patients need admission in well-appearing febrile travelers.

High-dose Dexamethasone in a Child With Enteric Encephalopathy Caused by Salmonella enterica serovar Typhi

Increased antimicrobial resistance to Salmonella species threatens successful treatment of typhoid and other infectious diseases. Consequently, rare complications arising from incompletely treated typhoid could increase in frequency. We describe a case of enteric encephalopathy caused by Salmonella enterica serovar Typhi and the utility of adjunct treatment with corticosteroids.

The first imported case of extensively drug-resistant Salmonella enterica serotype Typhi infection in Taiwan and the antimicrobial therapy

The first imported case of XDR typhoid fever in Taiwan contracted with a bacterial strain, which was most closely related to the bla_CTX-M-15-carrying strains linked to Pakistan. Meropenem, in combination with an antimicrobial with intracellular activity against Salmonella, should be used for the treatment of XDR typhoid fever.

Antimicrobial Therapy in the Context of the Damage-Response Framework: the Prospect of Optimizing Therapy by Reducing Host Damage

By design, antimicrobial agents act directly on microbial targets. These drugs aim to eliminate microbes and are remarkably effective against susceptible organisms. Nonetheless, some patients succumb to infectious diseases despite appropriate antimicrobial therapy. Today, with very few exceptions, physicians select antimicrobial therapy based on its activity against the targeted organism without consideration of how the regimen affects patients' immune responses. An important concept to emerge in the past few decades is that immune responses to microbes can be detrimental by enhancing host damage, which can translate into clinical disease. A central tenet of the damage-response framework (DRF) of microbial pathogenesis is that the relevant outcome of host-microbe interaction is the damage that occurs in the host, which can be due to microbial factors, host factors, or both. Given that host damage can make patients sick, reducing it should be a goal of treating infectious diseases. Inflammation and damage that stem from the host response to an infectious disease can increase during therapy with some antimicrobial agents and decrease during therapy with others. When a patient cannot eliminate a microbe with their own immune response, antimicrobial therapy is essential for microbial elimination, and yet it can affect the inflammatory response. In this essay, we discuss antimicrobial therapy in the context of the DRF and propose that consideration of the DRF may help tailor therapy to a patient's need to augment or reduce inflammation.

From Gut to Heart: Havoc in a Young Patient with Typhoid-associated Cardiomyopathy

Typhoid is an endemic hassle, especially in third-world countries like Pakistan. It is an enteric fever characterized by systemic manifestations that include high temperature and abdominal pain. If not properly treated, at times, it can transgress into complications predominantly involving the gut, where the site of pathology lies. Sometimes, however, it can involve other organ systems and pose diagnostic challenges owing to unfamiliar modes of presentation. Here in, we present a case of a 14-year-old male, previously afflicted and treated for typhoid who presented to the medical consult service with abdominal pain, high-grade fever, and mild chest discomfort. His hemodynamic parameters deteriorated within weeks as he developed pulmonary edema and hypoxemia. He was later diagnosed with echocardiography which earlier on, showed signs of acute myocarditis and eventually dilated cardiomyopathy. The patient was treated with antibiotics coupled with supportive and intensive care which yielded relief in his symptoms. He was later followed up with serial echocardiograms and showed improvement in the cardiac parameters.

Hydrocortisone in Vasodilatory Shock

Vasodilatory shock is the most common type of circulatory shock in critically ill patients; sepsis the predominant cause. Steroid use in septic shock gained favor in the 1970s; however, studies of high-dose steroids demonstrated excess morbidity and mortality. Lower dosage steroid use was driven by trials demonstrating improved hemodynamic status and the possibility of relative adrenal insufficiency; however, divergent results led to uncertainty about hydrocortisone treatment. Two recent trials are likely to reinforce the role of steroids in septic shock and change the recommendation in future clinical practice guidelines. Future work could include elucidating mechanisms of shock reversal, interaction of hydrocortisone with other agents, identifying steroid responsiveness using biochemical or gene signatures, and clarifying the role of fludrocortisone.

Steroids and Survival in Critically Ill Adult Patients: A Meta-analysis of 135 Randomized Trials

OBJECTIVE

Corticosteroids have important effects on intermediate outcomes in critically ill patients, but their effect on survival is unknown. The objective of this meta-analysis was to analyze the effect on mortality of corticosteroids in critical and perioperative settings.

DESIGN

A meta-analysis of randomized trials.

SETTING

PubMed, Embase, BioMed Central, Google Scholar, and the Cochrane Central Register of Controlled Trials were searched to February 1, 2018, for randomized trials comparing corticosteroids with placebo or standard care.

PARTICIPANTS

Critically ill or surgical adult patients.

INTERVENTIONS

Corticosteroids compared with placebo or standard care.

MEASUREMENTS AND MAIN RESULTS

A total of 44,553 patients from 135 studies were included. Overall, mortality in the corticosteroid group and in the control group were similar (16% v 16%; p = 0.9). Subanalyses identified a beneficial effect of corticosteroids on survival in patients with respiratory system diseases (9% v 13%; p < 0.001) and bacterial meningitis (28% v 32%; p= 0.04), and a detrimental effect on survival in patients with traumatic brain injury (22% v 19%; p < 0.001). No differences in mortality were found in patients with cardiac diseases (7% v 6%; p = 0.7), in patients undergoing cardiac surgery (2.8% v 3.2% p = 0.14), and when treatment duration or patient age were considered.

CONCLUSIONS

This meta-analysis documents the safety of corticosteroids in the overall critically ill population with the notable exception of brain injury patients, a setting where the authors confirmed their detrimental effect on survival. A possible beneficial effect of corticosteroids on survival was found among patients with respiratory diseases and in patients with bacterial meningitis.

Clinical profile, antibiotic susceptibility pattern of bacterial isolates and factors associated with complications in culture-proven typhoid patients admitted to an urban hospital in Bangladesh

OBJECTIVES

Typhoid fever is one of the major causes of morbidity and mortality in typhoid endemic countries like Bangladesh. However, data on the clinical and microbiological profile as well as factors associated with complications of typhoid in Bangladesh are scarce. We intended to characterise the clinical and microbiological profile of culture-proven typhoid fever and to identify factors associated with complications.

METHODOLOGY

Retrospective analysis of clinical data from 431 patients with culture-confirmed typhoid fever admitted to Dhaka hospital of International Centre for Diarrhoeal Disease Research, Bangladesh, between January 2010 and December 2014. Clinical and microbiological profiles of the patients including age, sex, and duration of illness prior to hospital admission, haematological parameters and the antimicrobial resistance profile of the infecting isolate, duration of hospital stay and defervescence time were examined by logistic regression to identify the factors associated with complications.

RESULT

About one of three patients were children under 5 years, and 21.5% of them were severely malnourished. During hospitalisation, 17.4% patients developed complications; mainly encephalopathy (6.7%), ileus (6.5%) and pneumonia (3.5%). Among culture-positive cases, 28.3% isolates showed multidrug resistant (MDR) and more than 90% of isolates were resistant to nalidixic acid and had intermediate sensitivity to ciprofloxacin. Five isolates were resistant to azithromycin; all isolates were sensitive to cefixime and ceftriaxone. Complication was independently associated with duration of fever before admission (adjusted odds ratio: 0.85; 95% CI: 0.074-0.97; P < 0.05), thrombocytopenia on admission (AOR: 2.84; 95% CI: 01.06-7.57; P < 0.05), duration of hospital stay (AOR: 1.34; 95% CI: 1.15-1.57; P < 0.01) and defervescence time (AOR: 0.83; 95% CI: 0.70-0.99; P < 0.05).

CONCLUSION

The high prevalence of typhoid fever among under-five children and complications among hospitalised patients are matters of concern. Sensitivity of Salmonella Typhi to ceftriaxone and cefixime was better than to other conventional antibiotics. Shorter duration of fever and thrombocytopenia on admission can be considered as early signs of complications.

Other Potentially Life-Threatening Conditions with Mucocutaneous Findings (Leptospirosis, Typhoid Fever, Dengue, Diphtheria, Murine Typhus)

There are several conditions with mucocutaneous findings that are potentially life-threatening, particularly in certain vulnerable populations. In this chapter, leptospirosis, typhoid fever, dengue, diphtheria, and murine typhus are reviewed. The disease time course of classic and atypical presentations is detailed to assist making the diagnosis in subtle cases. Associated symptoms are discussed as well as a comparison with disease mimics and differential diagnoses. Key diagnostic features are emphasized, and evidence-based management of each condition is detailed in this chapter.

Encephalitis in a traveller with typhoid fever: efficacy of corticosteroids

Typhoid fever is a bacterial infection caused by Salmonella typhi or S. paratyphi, recognized as a classical cause of fever in returning travellers. However, neuropsychiatric presentations are rarely reported in travellers diagnosed in western countries, whereas they are more commonly described in patients treated in endemic areas. We describe such a case and discuss the pathophysiologic mechanisms of this complication.

Salmonella Typhi-Induced Septic Shock and Acute Respiratory Distress Syndrome in a Previously Healthy Teenage Patient Treated With High-Dose Dexamethasone

Typhoid fever is commonly characterized by fever and abdominal pain. Rare complications include intestinal hemorrhage, bowel perforation, delirium, obtundation, and septic shock. Herein we describe the case of a previously healthy 16-year-old male without history of travel, diagnosed with typhoid fever complicated by septic shock and acute respiratory distress syndrome treated with high-dose dexamethasone. This case details severe complications of typhoid fever that are uncommonly seen in developed countries, and the successful response to high-dose dexamethasone as adjunct therapy. High-dose dexamethasone treatment has reportedly decreased Salmonella Typhi mortality, but controlled studies specifically performed in children are lacking, and most reports of its use are over 30 years old and all have originated in developing countries. Providers should include Salmonella Typhi in the differential diagnosis of the pediatric patient with fever, severe abdominal pain, and enteritis, and be aware of its potentially severe complications and the limited data on safety and efficacy of adjunctive therapies that can be considered in addition to antibiotics.

Rationale for Prolonged Glucocorticoid Use in Pediatric ARDS: What the Adults Can Teach Us

Based on molecular mechanisms and physiologic data, a strong association has been established between dysregulated systemic inflammation and progression of acute respiratory distress syndrome (ARDS). In ARDS patients, glucocorticoid receptor-mediated downregulation of systemic inflammation is essential to restore homeostasis, decrease morbidity and improve survival and can be significantly enhanced with prolonged low-to-moderate dose glucocorticoid treatment. A large body of evidence supports a strong association between prolonged glucocorticoid treatment-induced downregulation of the inflammatory response and improvement in pulmonary and extrapulmonary physiology. The balance of the available data from eight controlled trials (n = 622) provides consistent strong level of evidence for improving patient-centered outcomes and hospital survival. The sizable increase in mechanical ventilation-free days (weighted mean difference, 6.48 days; CI 95% 2.57-10.38, p < 0.0001) and intensive care unit-free days (weighted mean difference, 7.7 days; 95% CI, 3.13-12.20, p < 0.0001) by day 28 is superior to any investigated intervention in ARDS. For treatment initiated before day 14 of ARDS, the increased in hospital survival (70 vs. 52%, OR 2.41, CI 95% 1.50-3.87, p = 0.0003) translates into a number needed to treat to save one life of 5.5. Importantly, prolonged glucocorticoid treatment is not associated with increased risk for nosocomial infections (22 vs. 27%, OR 0.61, CI 95% 0.35-1.04, p = 0.07). Treatment decisions involve a tradeoff between benefits and risks, as well as costs. This low-cost, highly effective therapy is familiar to every physician and has a low risk profile when secondary prevention measures are implemented.

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

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.

Salmonella Infections in Childhood

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 choice of antibiotics for the management of typhoid fever should be guided by the local resistance pattern. Recommendations include using an extended spectrum cephalosporin, azithromycin, or a fluoroquinolone. Fecal carriage of Salmonella is an important factor in the spread of the organism to healthy individuals. The most important measures to prevent the spread and outbreaks of Salmonella infections and typhoid fever are adequate sanitation protocols for food processing and handling as well as hand hygiene. In the United States, 2 vaccines are commercially available against Salmonella Typhi. The WHO recommends the use of these vaccines in endemic areas and for outbreak control.

Risk factors for the development of severe typhoid fever in Vietnam

BACKGROUND

Typhoid fever is a systemic infection caused by the bacterium Salmonella enterica serovar Typhi. Age, sex, prolonged duration of illness, and infection with an antimicrobial resistant organism have been proposed risk factors for the development of severe disease or fatality in typhoid fever.

METHODS

We analysed clinical data from 581 patients consecutively admitted with culture confirmed typhoid fever to two hospitals in Vietnam during two periods in 1993-1995 and 1997-1999. These periods spanned a change in the antimicrobial resistance phenotypes of the infecting organisms i.e. fully susceptible to standard antimicrobials, resistance to chloramphenicol, ampicillin and trimethoprim-sulphamethoxazole (multidrug resistant, MDR), and intermediate susceptibility to ciprofloxacin (nalidixic acid resistant). Age, sex, duration of illness prior to admission, hospital location and the presence of MDR or intermediate ciprofloxacin susceptibility in the infecting organism were examined by logistic regression analysis to identify factors independently associated with severe typhoid at the time of hospital admission.

RESULTS

The prevalence of severe typhoid was 15.5% (90/581) and included: gastrointestinal bleeding (43; 7.4%); hepatitis (29; 5.0%); encephalopathy (16; 2.8%); myocarditis (12; 2.1%); intestinal perforation (6; 1.0%); haemodynamic shock (5; 0.9%), and death (3; 0.5%). Severe disease was more common with increasing age, in those with a longer duration of illness and in patients infected with an organism exhibiting intermediate susceptibility to ciprofloxacin. Notably an MDR phenotype was not associated with severe disease. Severe disease was independently associated with infection with an organism with an intermediate susceptibility to ciprofloxacin (AOR 1.90; 95% CI 1.18-3.07; p = 0.009) and male sex (AOR 1.61 (1.00-2.57; p = 0.035).

CONCLUSIONS

In this group of patients hospitalised with typhoid fever infection with an organism with intermediate susceptibility to ciprofloxacin was independently associated with disease severity. During this period many patients were being treated with fluoroquinolones prior to hospital admission. Ciprofloxacin and ofloxacin should be used with caution in patients infected with S. Typhi that have intermediate susceptibility to ciprofloxacin.

Evaluation of a typhoid/paratyphoid diagnostic assay (TPTest) detecting anti-Salmonella IgA in secretions of peripheral blood lymphocytes in patients in Dhaka, Bangladesh

BACKGROUND

Rapid and reliable diagnostic assays for enteric (typhoid and paratyphoid) fever are urgently needed. We report the characterization of novel approach utilizing lymphocyte secretions, for diagnosing patients with enteric fever by the TPTest procedure.

METHODOLOGY

TPTest detects Salmonella-specific IgA responses in lymphocyte culture supernatant. We utilized TPTest in patients with suspected enteric fever, patients with other illnesses, and healthy controls. We also evaluated simplified modifications of TPTest for adaptation in laboratories with limited facilities and equipment.

PRINCIPAL FINDINGS

TPTest was positive in 39 (27 typhoid and 12 paratyphoid A) patients confirmed by blood culture and was negative in 74 healthy individuals. Among 32 individuals with other illnesses, 29 were negative by TPTest. Of 204 individuals with suspected enteric fever who were negative by blood culture, 44 were positive by TPTest and the patients were clinically indistinguishable from patients with confirmed bacteremia, except they were more likely to be under 5 years of age. We evaluated simplifications in TPTest, including showing that lymphocytes could be recovered using lysis buffer or buffy coat method as opposed to centrifugation, that incubation of cells at 37°C did not require supplemental CO2, and that results were available for majority of samples within 24 hours. Positive results by TPTest are transient and revert to negative during convalescence, supporting use of the test in endemic areas. The results can also be read using immunodot blot approach as opposed to ELISA. Since no true gold standard currently exists, we used a number of definitions of true positives and negatives. TPTest had sensitivity of 100% compared to blood culture, and specificity that ranged from 78-97% (73-100, 95% CI), depending on definition of true negative.

CONCLUSION

The TPTest is useful for identification of patients with enteric fever in an endemic area, and additional development of simplified TPTest is warranted.

Host-pathogen interaction in invasive Salmonellosis

Salmonella enterica infections result in diverse clinical manifestations. Typhoid fever, caused by S. enterica serovar Typhi (S. Typhi) and S. Paratyphi A, is a bacteremic illness but whose clinical features differ from other Gram-negative bacteremias. Non-typhoidal Salmonella (NTS) serovars cause self-limiting diarrhea with occasional secondary bacteremia. Primary NTS bacteremia can occur in the immunocompromised host and infants in sub-Saharan Africa. Recent studies on host-pathogen interactions in Salmonellosis using genome sequencing, murine models, and patient studies have provided new insights. The full genome sequences of numerous S. enterica serovars have been determined. The S. Typhi genome, compared to that of S. Typhimurium, harbors many inactivated or disrupted genes. This can partly explain the different immune responses both serovars induce upon entering their host. Similar genome degradation is also observed in the ST313 S. Typhimurium strain implicated in invasive infection in sub-Saharan Africa. Virulence factors, most notably, type III secretion systems, Vi antigen, lipopolysaccharide and other surface polysaccharides, flagella, and various factors essential for the intracellular life cycle of S. enterica have been characterized. Genes for these factors are commonly carried on Salmonella Pathogenicity Islands (SPIs). Plasmids also carry putative virulence-associated genes as well as those responsible for antimicrobial resistance. The interaction of Salmonella pathogen-associated molecular patterns (PAMPs) with Toll-like receptors (TLRs) and NOD-like receptors (NLRs) leads to inflammasome formation, activation, and recruitment of neutrophils and macrophages and the production of pro-inflammatory cytokines, most notably interleukin (IL)-6, IL-1β, tumor necrosis factor (TNF)-α, and interferon-gamma (IFN)-γ. The gut microbiome may be an important modulator of this immune response. S. Typhimurium usually causes a local intestinal immune response, whereas S. Typhi, by preventing neutrophil attraction resulting from activation of TLRs, evades the local response and causes systemic infection. Potential new therapeutic strategies may lead from an increased understanding of infection pathogenesis.

Factors associated with encephalopathy in patients with Salmonella enterica serotype Typhi bacteremia presenting to a diarrheal hospital in Dhaka, Bangladesh

To characterize clinical correlates of typhoid fever-associated encephalopathy, we performed a retrospective chart review of patients with Salmonella enterica serotype Typhi bacteremia who were hospitalized at the International Centre for Diarrhoeal Disease Research, Bangladesh, from February of 2009 to June of 2011. Of 207 patients bacteremic with Salmonella Typhi who were ≥ 5 years of age, we identified 43 (21%) patients with encephalopathy. Univariate analysis revealed that patients with encephalopathy more often presented at ages of 10-24 years and had severe dehydration, low oxygen saturation, high respiratory rate, low leukocyte count, low platelet count, and Widal flagellar H agglutinin (TH) titer ≥ 1:640 compared with typhoid patients without encephalopathy. Multivariate analysis using logistic regression showed that age, dehydration, leukocyte count, and Widal TH titer were independently associated with encephalopathy. Our findings suggest that age, severity of disease, and immune responses are associated with encephalopathy during Salmonella Typhi bacteremia, perhaps reflecting the impact of prominent inflammatory responses.

Etiology of acute, non-malaria, febrile illnesses in Jayapura, northeastern Papua, Indonesia

We conducted a prospective, inpatient fever study in malaria-endemic Papua, Indonesia to determine non-malaria fever etiologies. Investigations included malaria blood films, blood culture, paired serologic samples analysis for dengue, Japanese encephalitis, leptospirosis, scrub typhus, murine typhus, and spotted fever group rickettsia. During 1997–2000, 226 patients (127 males and 99 females) 1–80 years of age (median age = 25 years) were enrolled. Positive blood cultures (n = 34, 15%) were obtained for Salmonella Typhi (n = 13), Escherichia coli (n = 8), Streptococcus pneumoniae (n = 6), Staphylococcus aureus (n = 5), Streptococcus pyogenes (n = 1), and Klebsiella pneumoniae (n = 1). Twenty (8.8%) patients were positive for leptospirosis by polymerase chain reaction. Eighty (35.4%) of 226 patients had ≥ 1 positive serology, diagnostic for 15 rickettsial and 9 dengue cases. Acid-fast bacilli–positive sputum was obtained from three patients. Most common confirmed (81 of 226, 35.8%)/suspected diagnoses were typhoid fever (n = 41), pneumonia (n = 29), leptospirosis (n = 28), urinary tract infections (n = 20), rickettsioses (n = 19), dengue (n = 17), and meningitis/encephalitis (n = 15). There were 17 deaths, 7 (46.7%) were caused by meningitis/encephalitis. Multiple positive serologic results and few confirmed diagnoses indicate the need for improved diagnostics.

Claims for improved survival from systemic corticosteroids in diverse conditions: an umbrella review

BACKGROUND

Systemic corticosteroids have been proposed for numerous indications and there are many claims that corticosteroids can reduce mortality in diverse conditions.

METHODS

We performed an umbrella, agenda-wide review of the evidence on systemic corticosteroids and mortality, focusing primarily on large trials (defined as those with > 100 deaths) and meta-analyses. Searches were performed in PubMed and Cochrane Central Register of Controlled Trials (last update February 2011). We also examined whether spurious subset analyses may be responsible for claims of survival benefits in indications where only small trials had been available.

RESULTS

Among 257 identified randomized trials with mortality data in their abstract, we found 14 large trials pertaining to 10 different indications. Although 10 of these 14 trials have reported statistically significant survival differences in subset analyses, none shows a nominally statistically significant (P < 0·05) decrease in death risk for any of the tested conditions when all deaths on all randomized patients are analysed. Meta-analyses for these conditions show statistically significant reductions in mortality only with antenatal corticosteroids for preterm labour (relative risk 0·77, 95% CI, 0·67-0·89) and in tuberculous meningitis (relative risk 0·78, 95% CI, 0·67-0·91). For conditions without any large trials, statistically significant reductions in mortality in meta-analyses were noted for Pneumocystis pneumonia (relative risk 0·54, 95% CI, 0·38-0·79) and alcoholic hepatitis (relative risk 0·63, 95% CI, 0·50-0·80). Many small trials that claim significant benefits, even those for classic indications such as typhoid fever and tetanus, have shown these benefits only in subset analyses.

CONCLUSIONS

Corticosteroids have been documented to decrease mortality in some indications, in particular, antenatal use for preterm labour, tuberculous meningitis, Pneumocystis pneumonia, and alcoholic hepatitis. Many postulated benefits of corticosteroids on mortality may reflect 'vibration of treatment effects' leading to false-positive claims from spurious subset analyses and even for standard indications, such biases may have inflated the treatment effect estimates. More large trials are needed for serious, common conditions where use of corticosteroids is proposed.

Effect of rickettsial toxin VapC on its eukaryotic host

Rickettsia are intracellular bacteria typically associated with arthropods that can be transmitted to humans by infected vectors. Rickettsia spp. can cause mild to severe human disease with a possible protection effect of corticosteroids when antibiotic treatments are initiated. We identified laterally transferred toxin-antitoxin (TA) genetic elements, including vapB/C, in several Rickettsia genomes and showed that they are functional in bacteria and eukaryotic cells. We also generated a plaque assay to monitor the formation of lytic plaques over time and demonstrated that chloramphenicol accelerates host cell lysis of vapB/C-containing Rickettsia. Whole-genome expression, TUNEL and FISH assays on the infected cells following exposure to the antibiotic revealed early apoptosis of host cells, which was linked to over-transcription of bacterial vapB/C operons and subsequent cytoplasmic VapC toxin release. VapC that is expressed in Escherichia coli and Saccharomyces cerevisiae or microinjected into mammalian cells is toxic through RNase activity and is prevented by dexamethasone. This study provides the first biological evidence that toxin-antitoxin elements act as pathogenic factors in bacterial host cells, confirming comparative genomic evidence of their role in bacterial pathogenicity. Our results suggest that early mortality following antibiotic treatment of some bacterial infections can be prevented by administration of dexamethasone.

Impact of salmonella infection on host hormone metabolism revealed by metabolomics

The interplay between pathogens and their hosts has been studied for decades using targeted approaches, such as the analysis of mutants and host immunological responses. Although much has been learned from such studies, they focus on individual pathways and fail to reveal the global effects of infection on the host. To alleviate this issue, high-throughput methods, such as transcriptomics and proteomics, have been used to study host-pathogen interactions. Recently, metabolomics was established as a new method to study changes in the biochemical composition of host tissues. We report a metabolomic study of Salmonella enterica serovar Typhimurium infection. Our results revealed that dozens of host metabolic pathways are affected by Salmonella in a murine infection model. In particular, multiple host hormone pathways are disrupted. Our results identify unappreciated effects of infection on host metabolism and shed light on mechanisms used by Salmonella to cause disease and by the host to counter infection.

Profile of Culture Positive Enteric Fever from Bangalore

BACKGROUND

Enteric fever is endemic in India. The aim of this study was to analyse the clinical, laboratory, antibiotic sensitivity profile and response to antibiotics of culture positive enteric fever patients from Bangalore.

METHODS

In this retrospective study only culture positive enteric fever patients were taken and their clinical, laboratory, antibiotic sensitivity profile and the clinical response to antibiotics studied.

RESULT

Eighty one culture positive enteric fever patients were taken into the study. Presenting symptoms included fever, pain abdomen (18.5%), loose stools (25%), vomiting (33%) and headache (30%). Absolute bradycardia at admission was not found in any of our patients. Normal or low total leucocyte count was seen in 97.5%. Typhoid hepatitis was seen in 8.5%. Salmonella enterica subspecies enterica serovar typhi (S typhi) were isolated in 80% of cases; 83% of all cases showed nalidixic acid resistance. All isolates were sensitive to chloramphenicol and third generation cephalosporins. Ciprofloxacin resistance was found in 19% cases. The time to defervescence in patients treated with ceftriaxone was 4.3 days. There was no statistical difference in time to defervescence in nalidixic acid resistant and sensitive strains. Complications included gastro intestinal bleed and encephalopathy.

CONCLUSION

Prevalence of nalidixic acid resistance is high, while clinical resistance to quinolones may be higher than that found in the laboratory which requires detailed study. Chloramphenicol sensitivity has returned and nalidixic acid resistant and sensitive isolates are uniformly sensitive to third generation cephalosporins with no difference in time to defervescence.