Multidrug-resistant typhoid fever

Clinical and antimicrobial susceptibility profile of typhoid fever in children in the era of antibiotic resistance

Enteric fever remains a significant public health problem in low- and middle-income countries with further challenges from emerging antimicrobial resistance. Our prospective study evaluated the current clinical and antimicrobial susceptibility profile of enteric fever in 88 children and compared it to previously established literature. Enteric fever usually presents with nonspecific signs and symptoms, with predominant respiratory complaints. A paradigm shift in the antimicrobial sensitivity pattern has been noted, with increasing resistance for first-line antibiotics and older antibiotics such as ampicillin, cotrimoxazole, and chloramphenicol showing good sensitivity. Thus, the introduction of the latter merits consideration.

HAV-induced acalculous cholecystitis: A case report and literature review

Hepatitis A virus (HAV) has some life-threatening extrahepatic complications, such as acute acalculous cholecystitis (AAC). We present HAV-induced AAC in a young female, based on clinical, laboratory, and imaging findings, and conduct a literature review. The patient became irritable, which progressed to lethargy, as well as a significant decline in liver function, indicating acute liver failure (ALF). She was immediately managed in the intensive care unit with close airway and hemodynamic monitoring after being diagnosed with ALF (ICU). The patient's condition was improving, despite only close monitoring and supportive treatment with ursodeoxycholic acid (UDCA) and N-acetyl cysteine (NAC).

Antimicrobial sensitivity patterns of enteric fever in Pakistan: a comparison of years 2009 and 2019

BACKGROUND

Pakistan is one of the endemic regions for typhoid fever and paratyphoid fever. This study aimed to identify the evolving antimicrobial sensitivity patterns of Salmonella species causing enteric fever and its implications on the clinical prescribing of antimicrobials.

METHODS

This was a retrospective descriptive study conducted at a university hospital. Antimicrobial resistance was defined in terms of non-resistant, multidrug resistant (MDR) and extended drug resistant (XDR) as per WHO guidance. Data were collected from the years 2009 and 2019. Chi squared was applied to test for statistical significance (p < 0.05).

RESULTS

A total of 200 patients (100 from 2009 and 100 from 2019) were included in the study. Non-resistant enteric fever cases reduced from 100% in 2009 to 44% in 2019, whereas the MDR and XDR enteric fever cases increased to 16% and 40%, respectively (p < 0.05). Cross tabulation carried out for individual drugs showed an independent rise in the sensitivities of individual first-line antimicrobials.

CONCLUSION

Antimicrobial resistant enteric fever has become a big challenge for Pakistan. The choice of antibiotic prescription has narrowed down to broader spectrum antimicrobials making it difficult to treat, leading to increased morbidity and mortality.

Occurrence of Typhoid Fever Complications and Their Relation to Duration of Illness Preceding Hospitalization: A Systematic Literature Review and Meta-analysis

BACKGROUND

Complications from typhoid fever disease have been estimated to occur in 10%-15% of hospitalized patients, with evidence of a higher risk in children and when delaying the implementation of effective antimicrobial treatment. We estimated the prevalence of complications in hospitalized patients with culture-confirmed typhoid fever and the effects of delaying the implementation of effective antimicrobial treatment and age on the prevalence and risk of complications.

METHODS

A systematic review and meta-analysis were performed using studies in the PubMed database. We rated risk of bias and conducted random-effects meta-analyses. Days of disease at hospitalization (DDA) was used as a surrogate for delaying the implementation of effective antimicrobial treatment. Analyses were stratified by DDA (DDA <10 versus ≥10 mean/median days of disease) and by age (children versus adults). Differences in risk were assessed using odds ratios (ORs) and 95% confidence intervals (CIs). Heterogeneity and publication bias were evaluated with the I2 value and funnel plot analysis, respectively.

RESULTS

The pooled prevalence of complications estimated among hospitalized typhoid fever patients was 27% (95% CI, 21%-32%; I2 = 90.9%, P < .0001). Patients with a DDA ≥ 10 days presented higher prevalence (36% [95% CI, 29%-43%]) and three times greater risk of severe disease (OR, 3.00 [95% CI, 2.14-4.17]; P < .0001) than patients arriving earlier (16% [95% CI, 13%- 18%]). Difference in prevalence and risk by age groups were not significant.

CONCLUSIONS

This meta-analysis identified a higher overall prevalence of complications than previously reported and a strong association between duration of symptoms prior to hospitalization and risk of serious complications.

Effectiveness of treatment regimens for Typhoid fever in the nalidixic acid-resistant S. typhi (NARST) era in South India

The epidemiology of typhoid fever in South Asia has changed. Multi-drug resistant (MDR) Salmonella typhi ( S. typhi) is now frequently resistant to nalidixic acid and thus labelled NARST. Treatment failure with the use of fluoroquinolones has been widely noted, forcing clinicians to adopt alternative treatment strategies. In this observational study, we looked at various treatment regimens and correlated clinical and microbiological outcomes. In 146 hospitalised adults, the median minimum inhibitory concentration (MIC) for ciprofloxacin was 0.38 µg/mL with a median fever clearance time (FCT) of eight days (range = 2-35 days). Of the regimens used, gatifloxacin and azithromycin had a shorter FCT of six days compared to ceftriaxone (ten days; P < 0.001). Though mortality and relapse in our cohort was low, NARST seemed to correlate with mortality ( P = 0.006). Gatifloxacin or azithromycin clearly emerge as the drugs of choice for treatment of typhoid in South India.

Reemergence of Chloramphenicol Sensitivity in Enteric Fever

BACKGROUND

Enteric fever is a global health problem and rapidly developing resistance to various drugs makes the situation more alarming. Drug sensitivity in Salmonella enterica serovar typhi and Salmonella enterica serovar paratyphi A isolated from 45 blood culture positive cases of enteric fever was tested to determine in-vitro susceptibility pattern of prevalent strains in northern India.

METHODS

Strains isolated from 45 blood culture positive cases of typhoid and paratyphoid fever over a period of three years were studied and their sensitivity patterns to chloramphenicol, ampicillin, ciprofloxacin, ceftriaxone, nalidixic acid, amikacin and ofloxacin were analysed.

RESULTS

Our results show a high sensitivity of both Salmonella enterica serovar typhi (96%) and Salmonella enterica serovar paratyphi A (100%) to chloramphenicol. Sensitivity to ciprofloxacin and amikacin was 88% and 84% respectively. All the isolates were sensitive to ofloxacin, nalidixic acid and ceftriaxone. Sensitivity of Salmonella enterica serovar paratyphi A was 100% to chloramphenicol, ciprofloxacin, ofloxacin, nalidixic acid and ceftriaxone, 95% to amikacin and 30% to ampicillin. Overall 44 out of 45 isolates of Salmonellae were sensitive to chloramphenicol.

CONCLUSION

These findings suggest changing pattern of antibiotic resistance in enteric fever with reemergence of chloramphenicol sensitivity in northern India.

Antimicrobial drug use in a small Indian community hospital

Antimicrobial drug use and overuse have been a topic of interest for many years, lately focusing on the growing resistance worldwide. This study was conducted in a small Indian hospital, where more than 80% of all admitted patients received antimicrobial drugs. Penicillin, gentamycin, co-trimoxazole, ciprofloxacin and metronidazole were most commonly used and all antimicrobial drugs were given empirically with no confirmation of the infective agent. Reports of increasing resistance to antimicrobial drugs in India, and elsewhere, necessitates a focus on how antimicrobials drugs are used in relation to investigations of resistance patterns among the local strains of pathogens. This study may be considered a base-line study, though of relevance for other hospitals, in particular in low-income areas, where development of resistance to standard antimicrobial drugs may have severe implications for both patients and health managers.

Multidrug resistant typhoid fever outbreak in Ercek Village-Van, Eastern Anatolia, Turkey: clinical profile, sensitivity patterns and response to antimicrobials

The present study discusses the clinical features and treatment outcomes during an outbreak caused by multidrug resistant (MDR) Salmonella typhi isolates from Van, Turkey. Of the 867 typhoid fever patients from the same village, 154 (17.8%) were hospitalised. A total of 42 (27.3%) cultures were positive. All S. typhi isolates were resistant to chloramphenicol, ampicillin and co-trimoxazole. Ceftriaxone was the most commonly used antibiotic (89%). It was found that the time-to-fever defervescence and the length of the hospital stay were greater for patients who were treated by ciprofloxacin than ceftriaxone (P < 0.001). Inappropriate antibiotic treatment should be discouraged in order to prevent the development of resistant strains of S. typhi.

Immunological responses against Salmonella enterica serovar Typhimurium Braun lipoprotein and lipid A mutant strains in Swiss-Webster mice: potential use as live-attenuated vaccines

We generated and characterized Salmonella enterica serovar Typhimurium mutants that were deleted for the genes encoding Braun lipoprotein (lpp) alone or in conjunction with the msbB gene, which codes for an enzyme required for the acylation of the lipid A moiety of lipopolysaccharide. Two copies of the lpp gene, designated as lppA and lppB, exist on the chromosome of S. Typhimurium. These mutants were highly attenuated in a mouse infection model and induced minimal histopathological changes in mouse organs compared to those seen in infection with wild-type (WT) S. Typhimurium. The lppB/msbB and the lppAB/msbB mutants were maximally attenuated, and hence further examined in this study for their ability to induce humoral and cellular immune responses. Importantly, infection of out-bred Swiss-Webster mice with the mutant S. Typhimurium generated superior T helper cell type 2 (Th2) responses compared to WT S. Typhimurium, as determined by measuring IgG subclasses and cytokines. WT S. Typhimurium induced higher levels of IgG2a in sera of infected mice, while the lppB/msbB and lppAB/msbB mutants mounted higher levels of IgG1 as determined by an enzyme-linked immunosorbent assay. Mice immunized with lppB/msbB and lppAB/msbB mutants rapidly cleared WT S. Typhimurium upon subsequent rechallenge, and naïve mice passively immunized with sera from animals infected with S. Typhimurium mutants were protected against subsequent challenge with WT S. Typhimurium. Splenic T cells produced higher levels of interferon-gamma following ex vivo exposure to WT S. Typhimurium, while splenic T cells infected with the above-mentioned two mutants evoked higher levels of interleukin-6. Further, mice infected with lppB/msbB and lppAB/msbB mutants showed much higher levels of splenic T cell activation as measured by CD44(+) expression on CD4(+) T cells by flow cytometry and by incorporation of (3)H-thymidine compared to mice that were infected with WT S. Typhimurium. We expect the lppB/msbB and lppAB/msbB mutants to be excellent live-attenuated vaccine candidates, because they induced minimal inflammatory responses and evoked stronger and specific antibody and cellular immune responses.

Epidemiology and risk factors for endemic typhoid fever in Uzbekistan

BACKGROUND

To investigate the risk factors for infection with endemic typhoid fever in the Samarkand region of Uzbekistan.

METHODS

Case-control study of culture-confirmed bloodstream infection with Salmonella Typhi. Patients were compared to age-matched community controls. Salmonella Typhi isolates were tested for antimicrobial susceptibility.

RESULTS

We enrolled 97 patients and 192 controls. The median age of patients was 19 years. In a conditional regression model, consumption of unboiled surface water outside the home [adjusted odds ratio (aOR)=3.0, 95% confidence interval (CI)=1.1-8.2], use of antimicrobials in the 2 weeks preceding onset of symptoms (aOR=12.2, 95% CI 4.0-37.0), and being a student (aOR=4.0, 95% CI 1.4-11.3) were independently associated with typhoid fever. Routinely washing vegetables (aOR 0.06, 95% CI 0.02-0.2) and dining at a tea-house (aOR 0.4, 95% CI 0.2-1.0) were associated with protection against illness. Salmonella Typhi resistant to ampicillin, chloramphenicol, and trimethoprim-sulfamethoxazole was identified in 6 (15%) of 41 isolates tested.

CONCLUSIONS

Endemic typhoid fever in Uzbekistan is transmitted by contaminated water. Recent use of antimicrobials also increased risk of infection. Targeted efforts at improving drinking water quality, especially for students and young adults, are likely to decrease transmission of typhoid fever. Measures to decrease the unnecessary use of antimicrobials would be expected to reduce the risk of typhoid fever and decrease the spread of multiple drug-resistant Salmonella Typhi.

Multidrug-resistant typhoid fever

OBJECTIVE

To study the epidemiological pattern, clinical picture, the recent trends of multidrug-resistant typhoid fever (MDRTF), and therapeutic response of ofloxacin and ceftriaxone in MDRTF.

METHODS

The present prospective randomized controlled parallel study was conducted on 93 blood culture-proven Salmonella typhi children. All MDRTF cases were randomized to treatment with ofloxacin or ceftriaxone.

RESULTS

Of 93 children, 62 (66.6%) were MDRTF. 24 cases were below 5 years, 26 between 5-10 years and 12 were above 10 years. Male to female ratio was 1.85: 1. Majority of cases came from lower middle socio-economic classes with poor personal hygiene. Fever was the main presenting symptom. Hepatomegaly and splenomegaly was present in 88% and 46% cases respectively. 19 (30.6%) cases developed complications. Mean defervescence time with ceftriaxone and ofloxacin was 4.258 and 4.968 days respectively.

CONCLUSION

MDRTF is still emerging as serious public and therapeutic challenge. Ceftriaxone is well-tolerated and effective drug but expensive whereas ofloxacin is safe, cost-effective and therapeutic alternative in treatment of MDRTF in children with comparable efficacy to ceftriaxone.

Studies on immunogenicity and protective efficacy of DnaJ of Salmonella Typhi against lethal infection by Salmonella Typhimurium in mice

In the present study DnaJ (HSP40) of Salmonella enterica serovar Typhi has been evaluated for its immunogenicity and efficacy in protecting mice against lethal challenge by S. enterica serovar Typhimurium infection. DnaJ was amplified by PCR of the genomic DNA of S. Typhi and subsequently cloned in pQE-30 expression vector. The protein was induced by IPTG and purified using Ni-NTA chromatography under denaturing conditions. After refolding in vitro the immune response was evaluated by injecting 40 microg DnaJ protein/mouse i.p. on 0th, 7th and 28th day. The results showed a significant increase in antibody titre and lymphocyte proliferation in animals immunised with DnaJ as compared to control. Further there was an appreciable increase in IL-2, IL-4, IFN-gamma production in lymphocytes isolated from immunised mice as compared to control. In this limited study, immunisation of mice with DnaJ was found to provide 70% protection against lethal challenge by S. Typhimurium indicating the possible use of DnaJ as vaccine candidate against typhoid.

Antibiogram pattern and seasonality of Salmonella serotypes in a North Indian tertiary care hospital

The antibiogram pattern and seasonal distribution of Salmonella serotypes were analysed retrospectively over a 6-year period from January 1999 to December 2004. Blood cultures received in the Bacteriology Laboratory were processed by standard procedures and the Salmonella spp. isolates were identified with specific antisera and standard biochemical tests. Antimicrobial susceptibility testing was carried out by a standard disc diffusion method and the minimum inhibitory concentration (MIC) of ciprofloxacin for 332 representative Salmonella isolates was determined by E test. Salmonella Typhi (75.7%) was the predominant serotype among 830 Salmonella spp. isolated during the study period followed by S. Paratyphi A (23.8%). The maximum number of enteric fever cases occurred during April-June (dry season) followed by July-September (monsoon season). There was a decrease in multidrug-resistant (MDR) S. Typhi, but MDR S. Paratyphi A isolates increased. There was also a dramatic increase in nalidixic acid-resistant isolates. All isolates were susceptible to third-generation cephalosporins and ciprofloxacin except one S. Typhi strain which demonstrated high-level ciprofloxacin resistance with a MIC of 16 mug/ml. A knowledge of the seasonal distribution and antibiotic resistance pattern of Salmonella in a particular geographical region is helpful in the delineation of appropriate control measures required for prevention of enteric fever.

Clinical outcomes in typhoid fever: adverse impact of infection with nalidixic acid-resistant Salmonella typhi

BACKGROUND

Widespread use of fluoroquinolones has resulted in emergence of Salmonella typhi strains with decreased susceptibility to fluoroquinolones. These strains are identifiable by their nalidixic acid-resistance. We studied the impact of infection with nalidixic acid-resistant S. typhi (NARST) on clinical outcomes in patients with bacteriologically-confirmed typhoid fever.

METHODS

Clinical and laboratory features, fever clearance time and complications were prospectively studied in patients with blood culture-proven typhoid fever, treated at a tertiary care hospital in north India, during the period from November 2001 to October 2003. Susceptibility to amoxycillin, co-trimoxazole, chloramphenicol, ciprofloxacin and ceftriaxone were tested by disc diffusion method. Minimum inhibitory concentrations (MIC) of ciprofloxacin and ceftriaxone were determined by E-test method.

RESULTS

During a two-year period, 60 patients (age [mean +/- SD]: 15 +/- 9 years; males: 40 [67%]) were studied. All isolates were sensitive to ciprofloxacin and ceftriaxone by disc diffusion and MIC breakpoints. However, 11 patients had clinical failure of fluoroquinolone therapy. Infections with NARST isolates (47 [78%]) were significantly associated with longer duration of fever at presentation (median [IQR] 10 [7-15] vs. 4 [3-6] days; P = 0.000), higher frequency of hepatomegaly (57% vs. 15%; P = 0.021), higher levels of aspartate aminotransferase (121 [66-235] vs. 73 [44-119] IU/L; P = 0.033), and increased MIC of ciprofloxacin (0.37 +/- 0.21 vs. 0.17 +/- 0.14 microg/mL; P = 0.005), as compared to infections with nalidixic acid-susceptible isolates. All 11 patients with complications were infected with NARST isolates. Total duration of illness was significantly longer in patients who developed complications than in patients who did not (22 [14.8-32] vs. 12 [9.3-20.3] days; P = 0.011). Duration of prior antibiotic intake had a strong positive correlation with the duration of fever at presentation (r = 0.61; P = 0.000) as well as the total duration of illness (r = 0.53; P = 0.000).

CONCLUSION

Typhoid fever caused by NARST infection is associated with poor clinical outcomes, probably due to delay in initiating appropriate antibiotic therapy. Fluoroquinolone breakpoints for S. typhi need to be redefined and fluoroquinolones should no longer be used as first-line therapy, if the prevalence of NARST is high.

Acute gastroenteritis in children : what role for antibacterials?

The aim of this article is to define the currently accepted role of antibacterials in the treatment of acute gastroenteritis in children. Most cases of acute gastroenteritis in children are viral, self-limited, and need only supportive treatment. Appropriate fluid and electrolyte therapy, with close attention to nutrition, remain central to therapy.Antibacterial therapy serves as an adjunct, to shorten the clinical course, eradicate causative organisms, reduce transmission, and prevent invasive complications. Selection of antibacterials to use in acute bacterial gastroenteritis is based on clinical diagnosis of the likely pathogen prior to definitive laboratory results. Antibacterial therapy should be restricted to specific bacterial pathogens and disease presentations. In general, infections with Shigella spp. and Vibrio cholera should usually be treated with antibacterials, while antibacterials are only used in severe unresponsive infections with Salmonella, Yersinia, Aeromonas, Campylobacter, Plesiomonas spp., and Clostridium difficile. Antibacterials should be avoided in enterohemorrhagic Escherichia coli infection. However, empiric therapy may be appropriate in the presence of a severe illness with bloody diarrhea and stool leucocytes, particularly in infancy and the immunocompromised. The benefits and risks of adverse drug reactions should be weighed before prescribing antibacterials. Moreover, a major concern is the emergence of antibacterial-resistant strains due to the widespread use of antibacterial agents.

Use of antibiotics in the poultry industry in Saudi Arabia: implications for public health

BACKGROUND

The use of antimicrobial agents in food-producing animals has become an important public health issue due to the spread of microbial resistance. This study was aimed at identifying the antimicrobial agents available for poultry use and highlighting their possible impact on public health.

MATERIALS AND METHODS

Twenty-three randomly selected poultry farms and all veterinary pharmacies in the Eastern Province of Saudi Arabia were surveyed for the antibiotics used or dispensed. Further, a comprehensive literature survey was performed.

RESULTS

Twenty-nine antimicrobial agents were identified as being available for poultry use, of which 22 (75.9%) were important for the treatment of human infections. Enrofloxacin, oxytetracycline, ampicillin, neomycin, sulphamethoxazole, colistin, doxycycline and erythromycin were the most frequently used drugs. Food-borne hypersensitivity reactions and the emergence of microbial resistance, as well as cross-resistance to the various groups of antibiotics in animals and its transfer to human pathogens, are well documented.

CONCLUSION

The misuse of antibiotics in the local poultry industry poses a serious health risk to the public and may complicate the treatment of human infections. The veterinary use of antimicrobial agents, especially those with dual animal and human applications, should therefore be restricted. The establishment of a government department concerned with food and drug safety is also highly recommended.