This Article
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Mehta, G.
Right arrow Articles by Arya, S. C.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Mehta, G.
Right arrow Articles by Arya, S. C.

 Previous Article

Journal of Clinical Microbiology, March 2002, p. 1127-1128, Vol. 40, No. 3
0095-1137/02/$04.00+0     DOI: 10.1128/JCM.40.2.1127-1128.2002
Copyright © 2002, American Society for Microbiology. All Rights Reserved.

LETTER TO THE EDITOR

Capsular Vi Polysaccharide Antigen in Salmonella enterica Serovar Typhi Isolates


arrow
LETTER
 
Characterization of Salmonella enterica Serovar Typhi isolates for their Vi capsular polysaccharide antigen-related genetic sequences is desirable to define the role of isolates lacking such sequences in differential replication at unusual sites, including those coinfected with human immunodeficiency virus (HIV). Infection with Vi-negative strains might produce typhoid fever among those immunized with various Vi vaccines.

S. enterica serovar Typhi isolates lacking Vi capsular polysaccharide antigen, evident during slide agglutination with Vi typing antisera, have been known for several decades. High molarity turns off expression of Vi antigen with a false label of Vi-negative S. enterica serovar Typhi. Genotypic sequences linked with an expression of S. enterica serovar Typhi Vi capsular polysaccharide antigen are located at three widely separated chromosomal loci, viaA, viaB, and ompB. The ViaB locus, an operon that contains two genes that encode enzymes for the biogenesis and translocation of Vi, is present in all Vi-positive strains. Enzymes encoded by genes tviB, tviC, tviD, and tviE catalyze intracellular Vi synthesis. The translocation and anchoring of Vi to bacterial surface is through export genes, vexA, vexB, vexC, vexD, and vexE. Two other chromosomal regions, the ompB operon and viaA, which is allelic to resB-resC, have a role in expression of Vi capsular polysaccharide antigen in high molarity and other environmental signals (9). Recently, even S. enterica serovar Typhi isolates that lacked ViaB sequences were responsible for an epidemic of multidrug-resistant typhoid fever in Calcutta, India (10).

S. enterica serovar Typhi strains devoid of capsular Vi antigen are frequently found at the National Salmonella Phage Typing Centre in the Department of Microbiology at the Lady Hardinge Medical College, New Delhi, India. During the year 2000, the facility received 1,289 isolates of Salmonella enterica serovar Typhi from different collaborating centers in India and Nepal. Upon receipt, each individual isolate was cultured in nutrient broth for a subculture on MacConkey agar. Biochemical, serological, and antibiotic sensitivity profiles were worked out. The presence or otherwise of Vi antigen was confirmed at room temperature by slide agglutination employing Vi typing antiserum (Murex Biotech Ltd., Dartford, England). The antibiotic sensitivity was carried out by disk diffusion method.

There were 113 Vi-negative Salmonella enterica serovar Typhi isolates drawn, including 88 isolates from blood, 3 isolates from bone marrow, and 1 isolate from a stool specimen. Such Vi-negative Salmonella enterica serovar Typhi were drawn from the patients presenting at the collaborating centers located in the northern, central, eastern, and southern parts of India and Nepal. Among the 113 isolates, 34 were resistant to ampicillin, tetracycline, chloramphenicol, and cotrimoxazole. None of the Salmonella enterica serovar Typhi isolates was resistant to ciprofloxacin or cephalexin. There was no information regarding the HIV serological status of any of the patients.

Vi-negative Salmonella enterica serovar Typhi isolates, though less infective than Vi-positive isolates, can cause a disease indistinguishable from the one caused by Vi-positive isolates (3). They could replicate selectively at abnormal sites in immunocompromised individuals. S. enterica serovar Typhi and HIV coinfection is frequent (8). Vi-negative isolates are frequently associated with glomerulonephritis, hepatic dysfunction (5), common iliac artery occlusion, and perforation of terminal ileum and appendix (1). Salmonella enterica serovar Typhi even caused thyroiditis in a 62-year-old woman (4), multiple brain abscesses in a 2-month-old girl (2), and gluteal hematoma (7).

Vi-negative S. enterica serovar Typhi, on its entry to an intracellular niche, is protected from Vi antibody (3). Any prophylactic vaccine that does not elicit cellular immunity would be unlikely to confer protection against an intracellular replication of Vi-negative S. enterica serovar Typhi. That might have occurred during the trial with conjugated polysaccharide S. enterica serovar Typhi vaccine bound to nontoxic recombinant Pseudomonas aeruginosa endotoxin A (rEPA) in the Dong Thap Province in Vietnam. There were four isolations of S. enterica serovar Typhi from vaccinated children (6). Vi characterization, both phenotypic and genotypic, of S. enterica serovar Typhi isolates in prospective trials with any typhoid vaccine should be mandatory. That would reveal the role of Vi-negative S. enterica serovar Typhi in rare and unexpected failures with the vaccines presently in use, typhoid prophylactic vaccines.

The pathogenicity of typhoid fever is being evaluated intensively in Vietnam by Wain et al. (11). Among the 120 Vietnamese patients with enteric fever, there was a 30-fold higher concentration of S. enterica serovar Typhi in bone marrow. Furthermore, bacterial counts were elevated further with an increasing duration of illness. There were no details about a presence or absence of Vi antigen in the Vietnamese S. enterica serovar Typhi isolates. Such an investigation, retrospective and prospective, on S. enterica serovar Typhi isolates in Vietnam and elsewhere would be essential to evaluate any intracellular accumulation and dissemination of Vi-negative S. enterica serovar Typhi isolates. A deficient cellular immunity in the host could encourage even prolonged persistence of S. enterica serovar Typhi at aberrant locations.

To conclude, fiscal input for a microbiological surveillance for genotypic characterization of S. enterica serovar Typhi would be cost-effective. Apart from gaining fundamental information regarding pathogenesis of typhoid fever, with such support it would be possible to assay the efficacy of the newer conjugated typhoid vaccines. Moreover, Vi genotypic characterization of S. enterica serovar Typhi would be an asset to reference centers associated with any in-depth investigations performed with Salmonella enterica serovar Typhi.


arrow
REFERENCES
 
    1
  1. Golkai, V. K. and R. Makunike. 1997. Perforation of terminal ileum and appendix in typhoid enteritis: report of two cases. East Af. Med. J. 74:796-799.
    2. 2
  2. Hanel, R. A., J. C. Araujo, A. Antoniuk, L. F. da Silva Ditzel, L. T. Flenik Martines, and M. N. Linhares. 2000. Neurological dysfunction in a 2-month-old girl. Surg. Neurol. 53:86-90.[CrossRef][Medline]
    3. 3
  3. Homick, R. B., S. E. Gresiman, T. E. Woodward, H. L. DuPont, A. T. Dawkins, and M. J. Snyder. 1970. Typhoid fever: pathogenesis and immunological control (second of two parts). N. Engl. J. Med. 283:686-691.
    4. 4
  4. Jasma, A. Y., Rohizak, F. A. Meah, and B. T. Sulaiman. 1998. Typhoid thyroiditis. Med. J. Malaysia 53:109-111.[Medline]
    5. 5
  5. Khan, M., Y. Coovadia, and A. W. Sturm. 1997. Typhoid fever and asymptomatic human immunodeficiency virus infection: a report of 10 cases. J. Clin. Gastroenterol. 25:507-512.[CrossRef][Medline]
    6. 6
  6. Lin, F. Y., V. A. Hao, H. B. Khein, et al. The efficacy of a Salmonella typhi Vi conjugated vaccine in two- to-five year old children. N. Engl. J. Med. 344:1263-1269.
    7. 7
  7. Lindeberg, J. A., and E. A. Mouritsen. 1997. Gluteal hematoma infected with multiresistant Salmonella typhi. Ugeskar Laeger 160:54-55.
    8. 8
  8. Manfield, D., R. C. Donzelli, S. Talo, S. M. Guzman, and F. Chiodo. 1998-1999. Typhoid fever and HIV infection: a rare disease association in industrialized countries. Int. J. Infect. Dis 3:105-108.
    9. 9
  9. Pickard, D., J. Li, M. Roberts, D. Maskell, D. Hiorne, M. M. Levine, G. Dougan, and S. Chatfield. 1994. Characterization of a defined ompR mutant of Salmonella typhi:ompR is involved in the regulation of Vi polysaccharide expression. Infect. Immun. 62:3984-3993.[Abstract/Free Full Text]
    10. 10
  10. Saha, M. R., T. Ramamurthy, P. Dutta, and V. Mitra. 2000. Emergence of Salmonella typhi Vi-negative strains in an epidemic of multi-drug resistant typhoid fever in Calcutta, India. Nat. Med. J. India 13:164.
    11. 11
  11. Wain, J. P., V. B. Bay, H. Ninh, N. M. Doung, T. S. Diep, A. L. Walsh, C. M. Parry, R. P. Hasserjian, V. A. Ho, T. T. Hien, J. Farrar, N. J. White, and N. P. J. Day. 2001. Quantitation of bacteria in bone marrow from patients with typhoid fever: relationship between counts and clinical features. J. Clin. Microbiol. 39:1571-1576.[Abstract/Free Full Text]
Geeta Mehta
Lady Hardinge Medical College
New Delhi 110001, India

Subhash C. Arya*
Centre for Logistical Research and Innovation
M-122, Greater Kailash Part 2
New Delhi 110048, India

* E-mail: SUBHASJ{at}hotmail.com

Journal of Clinical Microbiology, March 2002, p. 1127-1128, Vol. 40, No. 3
0095-1137/02/$04.00+0     DOI: 10.1128/JCM.40.2.1127-1128.2002
Copyright © 2002, American Society for Microbiology. All Rights Reserved.



This article has been cited by other articles:

  • Raffatellu, M., Chessa, D., Wilson, R. P., Tukel, C., Akcelik, M., Baumler, A. J. (2006). Capsule-Mediated Immune Evasion: a New Hypothesis Explaining Aspects of Typhoid Fever Pathogenesis. Infect. Immun. 74: 19-27 [Full Text]  
  • Baker, S., Sarwar, Y., Aziz, H., Haque, A., Ali, A., Dougan, G., Wain, J., Haque, A. (2005). Detection of Vi-Negative Salmonella enterica Serovar Typhi in the Peripheral Blood of Patients with Typhoid Fever in the Faisalabad Region of Pakistan. J. Clin. Microbiol. 43: 4418-4425 [Abstract] [Full Text]  
  • Wain, J., House, D., Zafar, A., Baker, S., Nair, S., Kidgell, C., Bhutta, Z., Dougan, G., Hasan, R. (2005). Vi Antigen Expression in Salmonella enterica Serovar Typhi Clinical Isolates from Pakistan. J. Clin. Microbiol. 43: 1158-1165 [Abstract] [Full Text]  
  • Porwollik, S., Boyd, E. F., Choy, C., Cheng, P., Florea, L., Proctor, E., McClelland, M. (2004). Characterization of Salmonella enterica Subspecies I Genovars by Use of Microarrays. J. Bacteriol. 186: 5883-5898 [Abstract] [Full Text]  
  • Bueno, S. M., Santiviago, C. A., Murillo, A. A., Fuentes, J. A., Trombert, A. N., Rodas, P. I., Youderian, P., Mora, G. C. (2004). Precise Excision of the Large Pathogenicity Island, SPI7, in Salmonella enterica Serovar Typhi. J. Bacteriol. 186: 3202-3213 [Abstract] [Full Text]  
  • Nair, S., Alokam, S., Kothapalli, S., Porwollik, S., Proctor, E., Choy, C., McClelland, M., Liu, S.-L., Sanderson, K. E. (2004). Salmonella enterica Serovar Typhi Strains from Which SPI7, a 134-Kilobase Island with Genes for Vi Exopolysaccharide and Other Functions, Has Been Deleted. J. Bacteriol. 186: 3214-3223 [Abstract] [Full Text]  

This Article
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Mehta, G.
Right arrow Articles by Arya, S. C.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Mehta, G.
Right arrow Articles by Arya, S. C.

Copyright © 2009 by the American Society for Microbiology.   For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»