Prevalence and genetic analysis of phenotypically Vi- negative Salmonella typhi isolates in children from Kathmandu, Nepal

The Vi capsular polysaccharide (ViPS) protects Salmonella enterica subspecies enterica serotype Typhi (S.Typhi) in vivo by multiple mechanisms. Recent microbiological reports from typhoid endemic countries suggest that acapsulate S.Typhi may occur in nature and contribute to clinical typhoid fever that is indistinguishable from disease caused by capsulate strains. The prevalence and genetic basis of ViPS-negative S.Typhi isolates in children from Kathmandu, Nepal, were tested in 68 isolates. Although 5.9% of isolates tested negative for capsular expression by slide agglutination tests, a novel multiplex PCR assay and individual PCR analyses demonstrated the presence of all 14 genes responsible for the synthesis, transportation and regulation of the ViPS. These data suggest that phenotypically acapsulate S.Typhi may not have a genetic basis for the same.

A Rapid, Multiplexed, High-Throughput Flow-Through Membrane Immunoassay: A Convenient Alternative to ELISA

This paper describes a rapid, high-throughput flow-through membrane immunoassay (FMIA) platform. A nitrocellulose membrane was spotted in an array format with multiple capture and control reagents for each sample detection area, and assay steps were carried out by sequential aspiration of sample and reagents through each detection area using a 96-well vacuum manifold. The FMIA provides an alternate assay format with several advantages over ELISA. The high surface area of the membrane permits high label concentration using gold labels, and the small pores and vacuum control provide rapid diffusion to reduce total assay time to ~30 min. All reagents used in the FMIA are compatible with dry storage without refrigeration. The results appear as colored spots on the membrane that can be quantified using a flatbed scanner. We demonstrate the platform for detection of IgM specific to lipopolysaccharides (LPS) derived from Salmonella Typhi. The FMIA format provides analytical results comparable to ELISA in less time, provides integrated assay controls, and allows compensation for specimen-to-specimen variability in background, which is a particular challenge for IgM assays.

Antimicrobial susceptibility of Salmonella enterica serovars in a tertiary care hospital in southern India

BACKGROUND & OBJECTIVES

Salmonella enterica serovars Typhi and Paratyphi are predominantly known to cause enteric fever. Multidrug resistance in S. Tphi and S. Paratyphi has emerged as a cause of concern. This study was done to evaluate status in antimicrobial susceptibility patterns of Salmonella enterica serovar Typhi (S. Typhi) and S. Paratyphi obtained from blood culture in a tertiary care hospital in south India.

METHODS

Blood isolates of Salmonella species over a two year period between May 2009 and June 2011 were studied. A total of 322 isolates of Salmonella species were tested for antimicrobial susceptibility by Kirby-Bauer disc diffusion method. The MIC of ciprofloxacin was obtained by E-test, and azithromycin MIC was confirmed by agar dilution method for a limited number of isolates.

RESULTS

Of the total of 322 isolates studied, 186 (57.8%) were S. Typhi, 134 (41.6%) were S. Paratyphi A, and two were S. Paratyphi B. Of these, 44(13.66%) were resistant to ciprofloxacin (MIC <0.50 μg/ml) and 296 (91.9%) were nalidixic acid resistant. Of these 296 nalidixic acid resistant isolates, 278 (94%) were susceptible to ciprofloxacin by MIC criteria (<0.5 μg/ml). Of the 262 isolates tested for azithromycin sensitivity, only 120 (46%) were susceptible, whereas 81 (31%) were resistant and 55 (21%) showed intermediate susceptibility. Of the isolates, 322 (90%) were susceptible to ampicillin and (95%) were susceptible to co-trimoxazole. However, all the isolates were susceptible to chloramphenicol and ceftriaxone.

INTERPRETATION & CONCLUSIONS

Nalidixic acid resistance screening is not a reliable surrogate indicator of ciprofloxacin resistance. Ciprofloxacin MIC should to be routinely done. Azithromycin resistance appears to be emerging. However, isolates showed a high degree of susceptibility to ampicillin, co-trimoxazole and chloramphenicol. Thus, antibiotics like ampicillin and co-trimoxazole may once again be useful for the management of enteric fever in southern India.

Multifocal choroiditis following simultaneous hepatitis A, typhoid, and yellow fever vaccination

The paper describes the first reported case of multifocal choroiditis following simultaneous hepatitis-A, typhoid, and yellow fever vaccinations. A 33-year-old male developed sudden onset of flashing lights and floaters in his right eye 3 weeks following hepatitis A, typhoid, and yellow fever vaccinations. Fundus examination and angiography confirmed the presence of multiple peripheral chorioretinal lesions. These lesions demonstrated characteristic morphologic changes over a period of 8 weeks which were consistent with a diagnosis of self-resolving multifocal choroiditis. Vaccine-induced intraocular inflammation has been described infrequently. We demonstrate the first case of self-resolving multifocal choroiditis following simultaneous administration of hepatitis A, yellow fever, and typhoid immunizations.

A plausible explanation for male dominance in typhoid ileal perforation

The phenomenon of consistent male dominance in typhoid ileal perforation (TIP) is not well understood. It cannot be explained on the basis of microbial virulence, Peyer’s patch anatomy, ileal wall thickness, gastric acidity, host genetic factors, or sex-linked bias in hospital attendance. The cytokine response to an intestinal infection in males is predominantly proinflammatory as compared with that in females, presumably due to differences in the sex hormonal milieu. Sex hormone receptors have been detected on lymphocytes and macrophages, including on Peyer’s patches, inflammation of which (probably similar to the Shwartzman reaction/Koch phenomenon) is the forerunner of TIP, and is not excluded from the regulatory effects of sex hormones. Hormonal control of host-pathogen interaction may override genetic control. Environmental exposure to Salmonella typhi may be more frequent in males, presumably due to sex-linked differences in hygiene practices and dining-out behavior. A plausible explanation of male dominance in TIP could include sex-linked differences in the degree of natural exposure of Peyer’s patches to S. typhi. An alternative explanation may include sexual dimorphism in host inflammatory response patterns in Peyer’s patches that have been induced by S. typhi. Both hypotheses are testable.

Evaluation of the current trend of nalidixic acid susceptibility in typhoidal Salmonellae; a marker of therapeutic failure for the fluoroquinolones

BACKGROUND AND OBJECTIVES

Typhoid is a major health problem faced by the developing countries like Pakistan. More than 20 million cases are reported annually worldwide. Currently fluoroquinolones are the drugs of choice to treat typhoid fever. In vivo resistance to fluoroquinolones leading to therapeutic failure is developing rapidly and is becoming a major concern for the clinicians. The objective of this study was to determine the sensitivity pattern of Nalidixic acid over the last four years

MATERIAL AND METHODS

A descriptive cross sectional study was carried out at the Microbiology Department of the Army Medical College, National University of Sciences and Technology, Rawalpindi from January 2006 to December 2009. All the isolates were dealt with standard microbiological procedures. The antimicrobial sensitivity of Nalidixic acid and Ciprofloxacin was determined using Kirby-Bauer disc diffusion method as per the guidelines of Clinical and Laboratory Standard Institute (CLSI).

RESULTS

Out of 240 isolates, 111 were Salmonella typhi and 129 were Salmonella paratyphi A. The resistance of the typhoidal Salmonella to Nalidixic acid has reached significant levels and it seems only a matter of time when hundred percent resistance will be encountered. All isolates were sensitive to Ciprofloxacin on disc diffusion method.

CONCLUSION

Resistance to Nalidixic acid predicting therapeutic failure with fluoroquinolones is on a steady rise.

Incidence of typhoid bacteremia in infants and young children in southern coastal Pakistan

INTRODUCTION

The burden of typhoid fever in preschool children is not well recognized. The purpose of this study was to estimate the incidence of typhoid bacteremia in Pakistani children <5 years of age, with a focus on children younger than 2 years of age. This will help to inform prevention policies in highly endemic countries.

METHODS

Household surveillance from February 1, 2007 to May 12, 2008, was carried out by community health workers in 2 low-income, coastal communities of Karachi. Workers referred each sick child <5 years old to the local clinic. Blood for culture was obtained from those who gave consent, and inoculated in BACTEC Peds Plus bottles (Becton Dickinson, Sparks, MD) and processed per manufacturer's guidelines.

RESULTS

Overall, 5570 children contributed 3949 observation years. Blood culture was obtained from 1165 cases, yielding 36 pathogens. Salmonella Typhi was isolated in 16 cases, Salmonella Paratyphi A in 2 cases, and Salmonella Paratyphi B in 1 case. The incidence of typhoid bacteremia in children <2 years of age was 443.1 (95% confidence interval, 193.8-876.5) per 100,000 child years. The overall incidence rate of typhoid for children <5 years was 405.1 (95% confidence interval, 239.8-643.9) per 100,000 child years.

CONCLUSION

Typhoid is a common and significant cause of morbidity among young children in Pakistan, including children less than 2 years of age. Vaccines that provide protection to preschool children should be included in typhoid control efforts.

Salmonella Typhi and Plasmodium falciparum co-infection in a 12-year old girl with haemoglobin E trait from a non-malarious area in Bangladesh

A 12-year old girl from Uttar Badda, Dhaka, Bangladesh, was admitted to the Dhaka Hospital of ICDDR,B, with a 23-day history of fever and diarrhoea. After admission, she was treated for culture-proven Salmonella Typhi-associated infection and was discovered to be heterozygous for haemoglobin E. Despite treatment with appropriate antibiotics, the patient's condition did not improve, prompting further investigation, which revealed malaria due to Plasmodium falciparum. Dhaka is considered a malaria-free zone, and the patient denied recent travel outside Dhaka. Subsequently, the patient recovered fully on antimalarial therapy.

Financial barrier against access to diagnostic procedures among enteric fever suspects in highly-endemic areas of China

There is currently no public financial system that fully covers enteric fever suspects in China. This study aimed at documenting the level of access to definitive diagnostic procedures, especially haemoculture, for these patients and examining the effect of health insurance on access to such care. A hospital-based cross-sectional study was conducted in six counties of Yunnan province, using a structured questionnaire and data extraction from medical records. In total, 714 subjects were recruited. Chi-square test and logistic regression were employed for analysis of data. The majority of the subjects were young adults (52%) and farmers (55%) from low-income families (49%). Only 407 (57%) could afford haemoculture routinely advised by their doctors. Of these, 123 (30%) had haemoculture positive for Salmonella Typhi. After adjustment for income, not getting haemoculture was marginally associated with percentage of reimbursement from the insurance (p value for trend=0.047). Illiteracy was also an independent risk factor for this outcome. The poor coverage of haemoculture for patients suspected of having enteric fever in this endemic area was due to financial barrier. The current health-insurance system inadequately relieved the problem. Further financial reform to help patients suspected with enteric fever is required.

Evaluating investments in typhoid vaccines in two slums in Kolkata, India

New-generation vaccines against typhoid fever have the potential to reduce the burden of disease in areas where the disease is endemic. The case for public expenditure on typhoid Vi polysaccharide vaccines for two low-income, high-incidence slums (Narkeldanga and Tiljala) in Kolkata, India, was examined. Three measures of the economic benefits of the vaccines were used: private and public cost-of-illness (COI) avoided; avoided COI plus mortality risk-reduction benefits; and willingness-to-pay (WTP) derived from stated preference (contingent valuation) studies conducted in Tiljala in 2004. Benefits and costs were examined from a social perspective. The study represents a unique opportunity to evaluate typhoid-vaccine programmes using a wealth of new site-specific epidemiological and economic data. Three typhoid-vaccination strategies (targeting only enrolled school children, targeting all children, and targeting adults and children) would most likely pass a social cost-benefit test, unless benefits are restricted to include only avoided COI. All three strategies would be considered 'very cost-effective' using the standard comparisons of cost per disability-adjusted life-year avoided with per-capita gross domestic product. However, at an average total cost per immunized person of approximately US$ 1.1, a typhoid-vaccination programme would absorb a sixth of existing public-sector spending on health (on a per-capita basis) in India. Because there appears to be significant private economic demand for typhoid vaccines, the Government could design a financially-sustainable programme with user-fees. The results show that a programme where adults pay a higher fee to subsidize vaccines for children (who have higher incidence) would avoid more cases than a uniform user-fee and still achieve revenue-neutrality.

Typhus fever: an overlooked diagnosis

A case of typhus fever is presented. On admission, the clinical diagnosis was typhoid fever. Forty-eight hours after admission, the presence of subconjunctival haemorrhage, malena, and jaundice raised the possibility of a different aetiology, the two most likely differentials being dengue and typhus. Finally, a co-infection of typhoid and typhus was discovered. This uncommon clinical scenario should be taken into account in the management of patients with high fever on admission being treated as a case of typhoid fever.

Geographic variation of gallbladder cancer mortality and risk factors in Chile: a population-based ecologic study

Chile's gallbladder cancer rates are among the highest in the world, being the leading cause of cancer deaths among Chilean women. To provide insights into the etiology of gallbladder cancer, we conducted an ecologic study examining the geographical variation of gallbladder cancer and several putative risk factors. The relative risk of dying from gallbladder cancer between 1985 and 2003 was estimated for each of the 333 Chilean counties, using a hierarchical Poisson regression model, adjusting for age, sex and geographical location. The risk of gallbladder cancer mortality was analyzed in relation to region, poverty, Amerindian (Mapuche) population, typhoid fever and access to cholecystectomy, using logistic regression analysis. There were 27,183 gallbladder cancer deaths, with age and sex-adjusted county mortality rates ranging from 8.2 to 12.4 per 100,000 inhabitants. Rates were highest in inland and southern regions. Compared to the northern-coast, the northern-inland region had a 10-fold risk (95% of confidence interval (95% CI): 2.4-42.2) and the southern-inland region had a 26-fold risk (95% CI: 6.0-114.2). Independent of region, other risk factors for gallbladder cancer included a high Mapuche population (Odds ratio (OR):3.9, 95% CI 1.8-8.7), high typhoid fever incidence (OR:2.9, 95% CI 1.2-6.9), high poverty (OR:5.1, 95% CI 1.6-15.9), low access to cholecystectomy (OR:3.9, 95% CI 1.5-10.1), low access to hospital care (OR:14.2, 95% CI 4.2-48.7) and high urbanization (OR:8.0, 95% CI 3.4-18.7). Our results suggest that gallbladder cancer in Chile may be related to both genetic factors and poor living conditions. Future analytic studies are needed to further clarify the role of these factors in gallbladder cancer etiology.

Non-traumatic perforation of the small bowel

BACKGROUND

Non-traumatic perforation of the small bowel is an uncommon serious complication associated with high morbidity and mortality. Diseases that cause small bowel perforation vary in different areas of the world.

OBJECTIVE

To highlight difficulties in the diagnosis and management of non-traumatic perforation of small bowel.

MATERIAL AND METHODS

The medical records of four patients who have presented with non-traumatic perforation of the small bowel and were treated at Al-Ain Hospital during the last 5 years were studied retrospectively.

RESULTS

The presenting symptoms of all patients were similar. Erect chest X-ray has shown free air under diaphragm in 3 patients. Leukocytosis was present in only one patient. HIV was confirmed in one patient. Patients were diagnosed to have typhoid, HIV, hook worms and tuberculosis. Only the HIV patient died while the others were discharged home in a good condition.

CONCLUSION

Clinical findings of small bowel perforation are usually non specific and diagnosis is usually reached after surgery. The Histopathological examination of the small bowel ulcer were non conclusive in three patients. We have made our management plan according to the clinical findings. Non traumatic perforation in developing countries can be due to typhoid, HIV, tuberculosis and possibly hook worms.

Childhood Infectious Diseases: Overview

Of the annual burden of 10 million deaths among children under 5 years, a large proportion is associated with infectious diseases. These include 36% of the 4 million newborn deaths due to sepsis, pneumonia, diarrhea, and tetanus. Among the postneonatal deaths due to infections, estimates and uncertainty bounds include: 22% of deaths attributed to diarrhea (14–30%), 21% to pneumonia (14–24%), 9% to malaria (6–13%), and 1% to measles (1–9%). Some 42 countries alone account for almost 90% of the global burden of child mortality.

There is now sufficient evidence available on evidence-based interventions that can make a difference. It is estimated that almost two-thirds of these deaths are potentially preventable if interventions can be delivered at scale. Newborn infections and related mortality can be reduced by maternal tetanus toxoid vaccination, clean delivery, cord hygiene, exclusive and early breast-feeding, and prompt diagnosis and therapy. Diarrheal deaths can be prevented by adequate attention to breast-feeding, hand-washing and sanitation strategies, rota virus vaccine, adequate treatment including oral rehydration, appropriate dietary therapy, and oral zinc administration. Similarly, the global burden of pneumonia deaths can be reduced by vaccination strategies for measles, Hib, and pneumococcal disease, timely case detection, and treatment with appropriate antibiotics.

Ability of SPI2 mutant of S. typhi to effectively induce antibody responses to the mucosal antigen enterotoxigenic E. coli heat labile toxin B subunit after oral delivery to humans

We have evaluated an oral vaccine based on an Salmonella enteric serovar typhi (S. typhi) Ty2 derivative TSB7 harboring deletion mutations in ssaV (SPI-2) and aroC together with a chromosomally integrated copy of eltB encoding the B subunit of enterotoxigenic Escherichia coli heat labile toxin (LT-B) in volunteers. Two oral doses of 10(8) or 10(9)CFU were administered to two groups of volunteers and both doses were well tolerated, with no vaccinemia, and only transient stool shedding. Immune responses to LT-B and S. typhi lipopolysaccharide were demonstrated in 67 and 97% of subjects, respectively, without evidence of anti-carrier immunity preventing boosting of LT-B responses in many cases. Further development of this salmonella-based (spi-VEC) system for oral delivery of heterologous antigens appears warranted.

Antimicrobial susceptibility patterns of Salmonella enterica serotype typhi in eastern Nepal

The aim of the present study was to evaluate antimicrobial susceptibility patterns with special reference to multidrug resistance, susceptibility to ciprofloxacin, and bacteriophage typing of Salmonella enterica serotype Typhi isolated from blood sent for culture in a tertiary-care teaching hospital in eastern Nepal during January 2000-December 2004. In total, 132 strains of S. enterica Typhi, isolated from 2,568 blood culture samples collected from cases of suspected enteric fever, were tested for susceptibility to commonly-used antimicrobials by the disc-diffusion method. There were 35 multidrug-resistant strains. None of the isolates were resistant to ciprofloxacin. Of 52 isolates tested for minimum inhibitory concentration (MIC) of ciprofloxacin, 36 (69.23%) showed reduced susceptibility (MIC >0.25 mg/L). Of 112 strains tested for nalidixic acid susceptibility, 86 (76%) were resistant. Strains with reduced susceptibility to ciprofloxacin and resistance to nalidixic acid could be correlated. The commonest phage type was El. Nalidixic acid susceptibility could be a useful screening test for the detection of decreased susceptibility of S. Typhi to ciprofloxacin, a drug which is commonly used even for minor ailments in this area.

Typhoid and malaria co-infection - an interesting finding in the investigation of a tropical Fever

Malaysia is endemic for both these diseases and one should not be too surprised when faced with a diagnosis of co-infection of typhoid and malaria, as have been described in India and Canada. Here we describe one such case of Salmonella typhi and Plasmodium vivax infection.

Typhoid and malaria co-infection - an interesting finding in the investigation of a tropical Fever

In the investigation of fever in the tropics, two important diagnoses to be ruled out are typhoid and malaria. Both cause significant morbidity, mortality and economic loss. An estimated 17 million cases of typhoid are reported worldwide each year, resulting in 0.6 million deaths. Seventy five to eighty percent of these cases occur in Asia alone. Malaria affects 1 billion people each year; out of which 1-3 million die. Although caused by very different organisms - one a Gram negative bacilli, the other a protozoa, and transmitted via different mechanisms - ingestion of contaminated food and water and via the bite of an insect vector respectively, both typhoid and malaria share rather similar symptomatology and epidemiology. Malaysia is endemic for both these diseases and one should not be too surprised when faced with a diagnosis of co-infection of typhoid and malaria, as have been described in India and Canada. Here we describe one such case of Salmonella typhi and Plasmodium vivax infection.

Masculinity, Work, and the Fountain of Youth: Irving Fisher and the Life Extension Institute, 1914-31

In 1914, Progressive Era reformer Irving Fisher and wealthy contractor Harold Ley founded the Life Extension Institute (LEI), a business venture organized to address the problems of American health. For approximately two decades, from 1914 until the death of its medical director in 1931, the Life Extension Institute widely promoted its health maintenance program of annual physical examinations and health literature. The advertised goal of the LEI was to extend life without old age, as well as improve masculinity and good business practices through adherence to health principles. The first two decades of activities of the Life Extension Institute offer a window for examining early twentiethcentury ideas about the relationships between health, old age, and masculinity. The LEI literature constructed a picture of healthy, vigorous, and efficient American working men that helped to cement ideals of masculinity to ideals of health.