Randomized comparison of aztreonam and chloramphenicol in treatment of typhoid fever

Progress in the overall understanding of typhoid fever: implications for vaccine development

INTRODUCTION

Typhoid fever continues to have a substantial impact on human health, especially in Asia and sub-Saharan Africa. Access to safe water, and adequate sanitation and hygiene remain the cornerstone of prevention, but these are not widely available in many impoverished settings. The emergence of antibiotic resistance affects typhoid treatment and adds urgency to typhoid control efforts. Vaccines provide opportunities to prevent and control typhoid fever in endemic settings.

AREAS COVERED

Literature search was performed looking for evidence concerning the global burden of typhoid and strategies for the prevention and treatment of typhoid fever. Cost of illness, available typhoid and paratyphoid vaccines and cost-effectiveness were also reviewed. The objective was to provide a critical overview of typhoid fever, in order to assess the current understanding and potential future directions for typhoid treatment and control.

EXPERT COMMENTARY

Our understanding of typhoid burden and methods of prevention has grown over recent years. However, typhoid fever still has a significant impact on health in low and middle-income countries. Introduction of typhoid conjugate vaccines to the immunization schedule is expected to make a major contribution to control of typhoid fever in endemic countries, although vaccination alone is unlikely to eliminate the disease.

Role of classic signs as diagnostic predictors for enteric fever among returned travellers: Relative bradycardia and eosinopenia

BACKGROUND

The lack of characteristic clinical findings and accurate diagnostic tools has made the diagnosis of enteric fever difficult. We evaluated the classic signs of relative bradycardia and eosinopenia as diagnostic predictors for enteric fever among travellers who had returned from the tropics or subtropics.

METHODS

This matched case-control study used data from 2006 to 2015 for culture-proven enteric fever patients as cases. Febrile patients (>38.3°C) with non-enteric fever, who had returned from the tropics or subtropics, were matched to the cases in a 1:3 ratio by age (±3 years), sex, and year of diagnosis as controls. Cunha's criteria were used for relative bradycardia. Absolute eosinopenia was defined as an eosinophilic count of 0/μL.

RESULTS

Data from 160 patients (40 cases and 120 controls) were analysed. Cases predominantly returned from South Asia (70% versus 18%, p <0.001). Relative bradycardia (88% versus 51%, p <0.001) and absolute eosinopenia (63% versus 38%, p = 0.008) were more frequent in cases than controls. In multivariate logistic regression analysis, return from South Asia (aOR: 21.6; 95% CI: 7.17-64.9) and relative bradycardia (aOR: 11.7; 95% CI: 3.21-42.5) were independent predictors for a diagnosis of enteric fever. The positive likelihood ratio was 4.00 (95% CI: 2.58-6.20) for return from South Asia, 1.72 (95% CI: 1.39-2.13) for relative bradycardia, and 1.63 (95%CI: 1.17-2.27) for absolute eosinopenia. The negative predictive values of the three variables were notably high (83-92%);. however, positive predictive values were 35-57%.

CONCLUSIONS

The classic signs of relative bradycardia and eosinopenia were not specific for enteric fever; however both met the criteria for being diagnostic predictors for enteric fever. Among febrile returned travellers, relative bradycardia and eosinopenia should be re-evaluated for predicting a diagnosis of enteric fever in non-endemic areas prior to obtaining blood cultures.

Clinical features and outcome of typhoid fever and invasive non-typhoidal salmonellosis in a tertiary hospital in Belgium: analysis and review of the literature

OBJECTIVES

Typhoid fever (TF) occurs rarely in industrialized countries because of advances in health care and improvement of drinking water. Conversely, non-typhoid salmonellosis (NTS) remains widespread, because of food contamination or asymptomatic carriage. Non-typhoid salmonellosis can be severe when becoming invasive non-typhoid salmonellosis (iNTS). Although established prognostic indicators of the two pathologies are different, direct comparisons between iNTS and TF in the literature remain scarce. The purpose of this study was to analyse and compare demographic, clinical features and outcome of hospitalized patients with TF and iNTS.

METHODS

Demographic, clinical features and outcome were retrospectively analysed in a series of patients hospitalized between 2007 and 2012.

RESULTS

A total of 33 patients were enrolled, including 13 with established TF and 20 with iNTS. No differences between TF and iNTS patients were observed in incidence of fever, abdominal cramps, diarrhoea, headache, nausea and vomiting and duration of antibiotic therapy (≤ 7 days in both groups). Although the clinical outcome of TF patients was identical to that of iNTS patients, including incidence of complications, length of hospitalization and mortality (1/13 (7.7%) vs 2/20 (10%), P = 0.43), comorbidities were less frequent in the TF group than in the iNTS group (2/13 vs 15/20, P = 0.003).

CONCLUSION

The clinical profile and outcome of TF patients are similar to those with iNTS. Although comorbidities are more often associated with iNTS, the results of our study suggest that clinical management of these two diseases should remain similar.

Efficacy and safety of chloramphenicol: joining the revival of old antibiotics? Systematic review and meta-analysis of randomized controlled trials

OBJECTIVES

Chloramphenicol is an old broad-spectrum antibiotic. We assessed its efficacy and safety.

METHODS

This was a systematic review and meta-analysis. Electronic databases were searched to identify randomized controlled trials (RCTs) that assessed patients, of any age, with systemic bacterial infections that can cause sepsis and compared chloramphenicol alone versus other antibiotics. No restrictions on the date of publication, language or publication status were applied. The primary outcome assessed was overall mortality.

RESULTS

Sixty-six RCTs fulfilled the inclusion criteria, and these included 9711 patients. We found a higher mortality with chloramphenicol for respiratory tract infections [risk ratio (RR) 1.40, 95% CI 1.00-1.97] and meningitis (RR 1.27, 95% CI 1.00-1.60), both without heterogeneity. The point estimate was similar for enteric fever, without statistical significance. No statistically significant difference was found between chloramphenicol and other antibiotics regarding treatment failure, except for enteric fever (RR 1.46, 95% CI 1.07-2.00, without heterogeneity). This difference derived mainly from studies comparing chloramphenicol with fluoroquinolones (RR 1.85, 95% CI 1.07-3.2). There were no statistically significant differences between chloramphenicol and other antibiotics in terms of adverse events, including haematological events, except for anaemia, which occurred more frequently with chloramphenicol (RR 2.80, 95% CI 1.65-4.75, I(2) =0%), and gastrointestinal side effects, which were less frequent with chloramphenicol (RR 0.67, 95% CI 0.46-0.99, I(2) =0%). Many of the studies included were sponsored by pharmaceutical companies marketing the comparator drug to chloramphenicol, and this might have influenced the results.

CONCLUSIONS

Chloramphenicol cannot be recommended as a first-line treatment for respiratory tract infections, meningitis or enteric fever as alternatives are probably more effective. Chloramphenicol is as safe as treatment alternatives for short antibiotic courses. RCTs are needed to test this treatment against MDR organisms when better alternatives do not exist.

Iatrogenic neurology

Iatrogenic disease is one of the most frequent causes of hospital admissions and constitutes a growing public health problem. The most common type of iatrogenic neurologic disease is pharmacologic, and the central and peripheral nervous systems are particularly vulnerable. Despite this, iatrogenic disease is generally overlooked as a differential diagnosis among neurologic patients. The clinical picture of pharmacologically mediated iatrogenic neurologic disease can range from mild to fatal. Common and uncommon forms of drug toxicity are comprehensively addressed in this chapter. While the majority of neurologic adverse effects are listed and referenced in the tables, the most relevant issues are further discussed in the text.

A case of multidrug-resistant Salmonella enterica serovar Typhi treated with a bench to bedside approach

We report a relapsed case of a 25 year-old man with multi-drug resistant Salmonella serovar Typhi (MDRST) bacteremia who had recently returned from travel in India. Due to unresponsiveness to ciprofloxacin and ceftriaxone, we examined the strain's resistance to quinolones and extended-spectrum beta-lactamases (ESBLs). The strain had a single gyrA mutation at codon 83 (Ser83Phe), which explains its decreased susceptibility to fluoroquinolone and resistance to nalidixic acid. In the screening tests of ESBLs, TEM-1 was positive, which is beta-lactamase but not ESBL. The patient was finally successfully treated with meropenem and aztreonam. In the presence of clinical unresponsiveness despite favorable sensitivity tests, further laboratory evaluations are needed, which should include studies of genes related to antibiotic resistance and ESBLs. In addition, further prospective trials should be done about the possible inclusion of antibiotics not yet mentioned in the current guidelines. With MDRST on the rise worldwide, the most optimal and effective line of antibiotic defense needs to be devised.

27-jähriger Reiserückkehrer mit hohem Fieber und septischem Schock im Verlauf

A 27-year-old man was admitted with high fever and shivers eleven days after returning from vacation in Indonesia. Physical examination, laboratory values, abdominal ultrasound, and chest x-ray were not conclusive. All blood cultures yielded growth of Salmonella enterica serovar Typhi, and typhoid fever was diagnosed. Subsequently, the patient developed septic shock and pulmonary edema. In this case report epidemiological, clinical, and therapeutic aspects of typhoid fever are discussed with special emphasis on criteria for severe typhoid fever, which is treated with additional glucocorticoids.

Typhoid and paratyphoid fever

Typhoid fever is estimated to have caused 21.6 million illnesses and 216,500 deaths globally in 2000, affecting all ages. There is also one case of paratyphoid fever for every four of typhoid. The global emergence of multidrug-resistant strains and of strains with reduced susceptibility to fluoroquinolones is of great concern. We discuss the occurrence of poor clinical response to fluoroquinolones despite disc sensitivity. Developments are being made in our understanding of the molecular pathogenesis, and genomic and proteomic studies reveal the possibility of new targets for diagnosis and treatment. Further, we review guidelines for use of diagnostic tests and for selection of antimicrobials in varying clinical situations. The importance of safe water, sanitation, and immunisation in the presence of increasing antibiotic resistance is paramount. Routine immunisation of school-age children with Vi or Ty21a vaccine is recommended for countries endemic for typhoid. Vi vaccine should be used for 2-5 year-old children in highly endemic settings.

The treatment of multidrug-resistant and nalidixic acid-resistant typhoid fever in Viet Nam

Multidrug-resistant (MDR) Salmonella Typhi (resistant to chloramphenicol, ampicillin, and trimethoprim-sulphamethoxazole) and isolates with reduced susceptibility to fluoroquinolones (indicated by resistance to nalidixic acid, NaR) have caused epidemics and become endemic in southern Viet Nam during the 1990s. Short courses of ofloxacin have proved acceptable for treating MDR/NaS isolates of S. Typhi (ofloxacin MIC90 = 0.06 mg/l) causing uncomplicated disease. Ofloxacin (10-15 mg/kg/d) given for 2, 3, or 5 d cured >90% of patients with an average fever clearance time (FCT) of 4 d. Less than 3% of patients relapsed or had a positive post-treatment stool culture. In contrast, the response of NaR isolates (ofloxacin MIC90 = 0.5 mg/l) to such regimens is poor. For example, ofloxacin (20 mg/kg/d) given for 7 d cured only 75% of patients, with an FCT of 7 d, and 19% of patients had positive post-treatment faecal cultures. Currently available alternatives for NaR infections include ceftriaxone, cefixime, and azithromycin. These antimicrobials are reasonably effective but expensive. New, effective, and affordable regimens are needed to treat these NaR infections. Short courses of the new generation fluoroquinolones or combinations of the available antimicrobials are possible options.

Prophylactic therapy of Salmonella typhi septicemia in mice with a traditionally prescribed crude drug formulation

A crude drug formulation comprised of eight medicinal herb extracts was studied for in vitro and in vivo effect against Salmonella typhi. The formulation displayed inhibitory action against the test organism in vitro. Subsequently mice were challenged with a virulent strain of Salmonella typhi (Ty2) and the protective effect of the formulation was evaluated with post-infective, pre-infective, single and multiple dose schedules, administered either orally or subcutaneously. A schedule that included multiple divided doses prophylactically administered had a significant therapeutic effect.