Skip directly to search Skip directly to A to Z list Skip directly to page options Skip directly to site content

Volume 9, Number 10—October 2003


Antimicrobial Drug-resistant Salmonella Typhimurium (Reply to Helms)

Suggested citation for this article

Read original article.

Read Helms' reply.

In Reply to Helms: In the article by Helms et al., Helms concludes that infections with Salmonella Typhimurium strains resistant to ampicillin, chloramphenicol, streptomycin, sulfonamide, and tetracycline (hereafter referred to as penta-resistant) were associated with higher death rates than infections with non–penta-resistant S. Typhimurium. Helms also concluded that infections with quinolone-resistant (nalidixine-resistant) S. Typhimurium were associated with higher death rates than quinolone-susceptible S. Typhimurium (1).

Table 2 in Helms’ article provides information that enables close scrutiny of this conclusion and comparison of the excess mortality associated with penta-resistant, quinolone-susceptible S. Typhimurium with the excess mortality of non–penta-resistant S. Typhimurium (1). In this letter, the Table is based on the original table. However, two additional comparisons have been added: the p values, which are not based on the data but are approximations based on the parameters in the table.

The conclusion is that only quinolone resistance is associated with excess mortality compared with nonresistant isolates. Penta-resistant, quinolone-susceptible S. Typhimurium has a risk ratio of 2.9 (1.1 to 7.9) compared to the ratio of non–penta-resistant isolates 2.1 (1.5 to 2.9). When these figures are compared, the approximate p value is 0.55, which, of course, is far from being significant. Thus, on the basis of the article by Helms, penta resistance may not pose a greater threat to human health than non–penta resistance. However, the measured effect of penta resistance is achieved by the inclusion of quinolone-resistant S. Typhimurium in the group.

Jan Dahl*Comments to Author 

Author affiliation: *Danish Bacon and Meat Council, Copenhagen, Denmark


  1. Helms M, Vastrup P, Gerner-Smidt P, Mølbak K. Excess mortality associated with antimicrobial drug-resistant Salmonella Typhimurium. Emerg Infect Dis. 2002;8:4905.PubMed


Suggested citation for this article: Dahl J. Antimicrobial drug-resistant Salmonella Typhimurium (reply to Helms). Emerg Infect Dis [serial online] 2003 Oct [date cited]. Available from: URL:

DOI: 10.3201/eid0910.020716

Related Links

Table of Contents – Volume 9, Number 10—October 2003


Please use the form below to submit correspondence to the authors or contact them at the following address:

Jan Dahl, Danish Bacon and Meat Council, Axeltory 3, 1609 Copenhagen V, Denmark; fax: 4533145756

character(s) remaining.

Comment submitted successfully, thank you for your feedback.