Specimens and culture media for the laboratory diagnosis of typhoid fever

Wain, John; Diep, To Song; Bay, Phan Van Be; Walsh, Amanda L.; Vinh, Ha; Duong, Nguyen Minh; Hó, Vô Anh; Hien, Tran Tinh; Farrar, Jeremy; White, Nicholas J.; Parry, Christopher M.; Day, Nicholas P. J.

doi:10.3855/jidc.164

Cited by 51 publications

(54 citation statements)

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“…4 Culture of the causative organism is considered an effective diagnostic procedure in suspected typhoid fever. 5 Cultures can be obtained from various body fluids including blood, bone marrow, urine, stool, and rose spots. Blood, urine, and stool culture are the better diagnostic methods, but they are expensive techniques and some bacterial culture facilities are often unavailable and also it requires laboratory equipment and technical training.…”

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confidence: 99%

Comparative study of Widal test against stool culture for typhoid fever suspected cases in southern Ethiopia

Ameya¹,

Atalel²,

Kebede³

et al. 2017

PLMI

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Introduction:Infection caused by Salmonella enterica subsp. serotype Typhi remains an important public health problem in developing countries. Culture is an effective diagnostic method of confirming this infection. Diagnosis in developing countries is mostly done by Widal test, which is nonreliable. The aim of this study was to compare the Widal test against stool culture in typhoid-suspected cases and to evaluate the agreement between test methods. Methodology: A cross-sectional study design was conducted on typhoid-suspected cases in southern Ethiopia. Collected data were entered into Epi-Info version 3.5.1 and exported to SPSS version 20.0 for further analysis. Kappa test was used to assess the agreement between the tests. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated to compare the Widal test against stool culture. Results: A total of 95 patients participated in the study, of whom 49 (51.6%) were females and 46 (48.4%) were males. The age range of the suspected cases were between 10 and 62 years, with mean age of 27.9 years. Of the examined cases, 65 (68.4%) were positive for slide agglutination Widal test, whereas only 19 (20.0%) were positive for S. enterica serotype Typhi by stool culture. The sensitivity, specificity, PPV, and NPV of slide agglutination test against stool culture were 84.2%, 35.5%, 24.6%, and 90.0%, respectively. Slide agglutination test has a poor agreement with the stool culture (kappa = 0.103), but tube titration test has a fair agreement with the stool culture (kappa = 0.325). Conclusion: Widal test has a low specificity and PPV but has better sensitivity and NPV than a stool culture. It also has a poor agreement with the stool culture. Therefore, physicians should not be totally dependent on the Widal test in endemic areas and in areas where it is the only diagnostic method for typhoid fever.

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confidence: 99%

Comparative study of Widal test against stool culture for typhoid fever suspected cases in southern Ethiopia

Ameya¹,

Atalel²,

Kebede³

et al. 2017

PLMI

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“…Briefly, five wellisolated colonies were seeded in 200 µL of distilled water, shaken for 10 seconds, boiled for 10 minutes, and centrifuged at 11,000 rpm for 5 minutes [22]. The supernatant was stored in a fresh tube at -20°C until PCR was performed.…”

Section: Dna Extractionmentioning

confidence: 99%

“…DNA extraction from bacterial colonies was made using the boiling prep method [22]. Briefly, five wellisolated colonies were seeded in 200 µL of distilled water, shaken for 10 seconds, boiled for 10 minutes, and centrifuged at 11,000 rpm for 5 minutes [22].…”

Section: Dna Extractionmentioning

confidence: 99%

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Detection of Salmonella human carriers in Colombian outbreak areas

Carvajal-Restrepo

Sánchez-Jiménez

Diaz-Rodriguez

et al. 2017

J Infect Dev Ctries

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Introduction: Salmonellosis, a zoonotic and foodborne disease, is a public health problem in developing countries. With the aim of identifying human carriers of Salmonella, a survey was performed in five regions of Colombia with reported salmonellosis outbreaks. Methodology: The general population and cholecystectomy surgical patients were included in this study. Stool samples from 667 volunteers and gallbladder bile samples from 199 surgical patients were examined. Detection of Salmonella from cultured stool and bile samples was determined by polymerase chain reaction (PCR). Multiplex PCR and biochemical and serological tests were performed to identify the serovars of the isolates. Results: Nine (1.35%) stool samples were positive for Salmonella: two S. Newport, two S. Anatum, one S. Sinstorf, and four Salmonella spp. A total of 11 gallbladder bile samples were positive: S. Enteritidis was isolated from 3 bile cultures (1.5%), and 8 samples (4%) were positive for Salmonella spp. Conclusions: Our results show the presence of Salmonella carriers in the inhabitants of regions with reported outbreaks and suggest that these carriers are potential sources of infection in endemic and epidemic cases. Carriers also suggest Salmonella zoonotic transmission, since broiler and beef cattle are hosts to the Salmonella serotypes isolated. It is important to establish the source of infection in regions where salmonellosis is endemic in order to control transmission.

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“…This seems to be a gross underestimate, due to poor availability and performance of diagnostics in countries where typhoid is endemic (2). The available laboratory methods, i.e., bacterial culture, serological markers, antigen detection, and nucleic acid amplification, are highly unsatisfactory in the field conditions.…”

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Acid Exposure Induces Multiplication of Salmonella enterica Serovar Typhi

Ahirwar¹,

Pratap²,

Patel³

et al. 2014

J Clin Microbiol

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Salmonella enterica serovar Typhi faces several environmental stresses while going through the stomach (acidic pH) to the small intestine (basic pH) and intracellularly in macrophages (acidic pH) in humans. The acidic pH followed by alkaline pH in the small intestine might be responsible for expression of certain stress-induced genes, resulting in not only better survival but also induction of multiplication and invasion of the bacterium in the small intestine. Based on this hypothesis, we developed a process wherein we exposed the blood, urine, and stool specimens from 90 acute typhoid fever patients and 36 chronic typhoid carriers to acidic pH to see the effect on isolation rate of S. Typhi. About 5 g of freshly passed unpreserved stool, a centrifuged deposit of 15 ml of urine, and 5 ml of blood clot were subjected to 5 ml of Luria-Bertani (LB) broth (pH 3.5) for 20 min, followed by enrichment in bile broth-selenite F broth. When the combined isolation from all 3 specimens, i.e., blood, urine, and stool, after acid exposure was considered, a total of 77.7% of the acute typhoid patients were observed to be positive for the isolation of the S. Typhi serotype, compared to 8.8% by the conventional method. Similarly, 42% (15/36) of chronic carriers yielded positive for S. Typhi growth after acid exposure, compared to 5.5% (2/36) by the conventional method. It therefore can be concluded that acid shock triggers the multiplication of the bacteria, resulting in better isolation rates from blood clot, stool, and urine specimens. The estimated global incidence of typhoid fever is about 26.9 million new cases with 1% mortality annually (1). This seems to be a gross underestimate, due to poor availability and performance of diagnostics in countries where typhoid is endemic (2). The available laboratory methods, i.e., bacterial culture, serological markers, antigen detection, and nucleic acid amplification, are highly unsatisfactory in the field conditions. There is an urgent need for optimization of culture methods because of the absolute specificity of culture isolation. High density (bone marrow) or large volume (Ͼ30 ml of peripheral blood) have been reported with satisfactory levels of sensitivity for Salmonella enterica serovar Typhi/Paratyphi isolated from acute typhoid fever cases. In patients with acute typhoid fever, the bacterial density has been reported to be 10-fold higher in bone marrow than in peripheral blood (3). However, both of the above options, i.e., higher blood volume or bone marrow aspirations, are not practical, even at the tertiary level of health care settings. Interestingly, a study from Vietnam reported a median count of 0.1 to 1.0 CFU of S. Typhi/ml of blood (range, 0.3 to 387) in cases of acute typhoid fever (4). It means 5 ml of routinely collected blood should have at least 5 bacterial cells sufficient enough to grow in artificial medium that are devoid of all antibacterial factors present in vivo. In routine practice, we hardly exceed 30% of the isolation rate of S. Typhi with the above-me...

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Specimens and culture media for the laboratory diagnosis of typhoid fever

Cited by 51 publications

References 20 publications

Comparative study of Widal test against stool culture for typhoid fever suspected cases in southern Ethiopia

Comparative study of Widal test against stool culture for typhoid fever suspected cases in southern Ethiopia

Detection of Salmonella human carriers in Colombian outbreak areas

Acid Exposure Induces Multiplication of Salmonella enterica Serovar Typhi

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