Skip directly to local search Skip directly to A to Z list Skip directly to navigation Skip directly to site content Skip directly to page options
CDC Home

Volume 11, Number 1—January 2005

Letter

Multidrug-resistant Salmonella Java

Suggested citation for this article

To the Editor: Since 2000, Salmonella enterica serovar Paratyphi B variant Java (S. Java) with resistance to antimicrobial drugs has been isolated with increasing frequency from patients in Scotland, England, Wales, and the Channel Islands. For England, Wales, and the Channel Islands, drug-resistant S. Java was found in humans: 25 in 2000, 36 in 2001, 49 in 2002, and 4 in 2003 (January 1–March 31). These isolates made up 35% of 325 strains of S. Java in human infections over the study period (L.R. Ward, unpub. data). A range of drug-resistant spectrums (R-types) have been observed, e.g., ASSpSuTm, ASSpSuTmCp, ASSpSuTTm, ACSSpSuT (A, ampicillin; C, chloramphenicol; S, streptomycin; Sp, spectinomycin; Su, sulphonamides; T, tetracyclines; Tm, trimethoprim; Cp, ciprofloxacin) (1). In general, isolates of S. Java of R-types ASSpSuTm, ASSpSuTmCp, and ASSpSuTTm, appear to be associated with imported poultry. In contrast, infections with isolates of R-type ACSSpSuT have not been associated with poultry, and organisms with the ACSSpSuT resistant spectrum have not been isolated from poultry in the United Kingdom (R.H. Davies, pers. comm.).

In England, Wales, and the Channel Islands, S. Java of R-type ACSSpSuT was isolated from human patients in 64 instances from 2000 to 2003 (5 in 2000, 22 in 2001, 34 in 2002, and 3 in 2003 [to March 31]). None of these cases were related to eating contaminated foods, and the ACSSpSuT antibiogram has not been isolated from strains of this serotype from foods in the United Kingdom. This resistance pattern corresponds to that of the epidemic clone of S. Typhimurium definitive phage type (DT) 104 (DT 104 ACSSpSuT), which caused many infections in humans and food production animals throughout Europe, the United States, and Canada in the 1990s (1). In all isolates of DT104 ACSSpSuT studied, from many different countries, the resistant gene cluster has been chromosomally integrated (1). Resistances have been contained in a 13-kb cluster composed of 2 integrons coding for resistance to SSp (1.0 kb) and ASu (1.2 kb), with the genes for resistance to chloramphenicol and tetracyclines located between these integrons (2,3). To investigate the possibility of the horizontal transfer of the ACSSpSuT gene cluster within S. enterica, we have characterized the resistance genes and associated structures in strains of S. Java of R-type ACSSpSuT and compared them with those in a strain of DT104 ACSSpSuT

From 2000 to 2002, a total of 20 isolates of S. Java of R-type ACSSpSuT from patients in England and Wales (18 isolates) and Scotland (2 isolates) were characterized by phage typing, plasmid profile typing, and pulsed-field gel electrophoresis (PFGE). Pulsed-field profiles of 3 additional isolates of S. Java of R-type ACSSpSuT from Scotland were compared with those of isolates from England and Wales by the electronic exchange of tagged image format files (TIFFs) in a Bionumerics database. Resistance genes were identified by polymerase chain reaction (PCR) with primers specific for blaTEM (A), blaCARB-2 (A), cmlA (chloramphenicol/florfenicol), catI (C), catIII (C), aadA2 (SSp), sul1 (Su), and tetG (T) (5). The presence of class 1 integrons was tested with the primers L1 and R1 (2). To identify the complete ACSSpSuT resistance gene cluster, long PCR was used on the basis of amplifying a 10,041-bp fragment of the DT104 isolate H3380 (4). Results were compared with those of standard strain of DT104 ACSSpSuT-P3170700, and DT104 drug-sensitive–P3343110 (4).

Five unrelated phage types, – 1 var 3 (6 isolates), 3b var 2 (5), Dundee (2), Worksop (3), and RDNC (4), and 3 closely-related pulsed-field types, differing by only 1 to 3 of 14 bands in the Xba1 PFGE profiles, were identified in the 20 isolates studied; 2 of these pulsed-field types were observed in the electronically transmitted images of the 3 isolates from Scotland. These pulsed-field profile types have been designated SPTJXB001 through SPTJXB003. Of these, SPTJXB002 predominated, being present in 11 of the isolates studied, belonging to 3 phage types. SPTJXB001 was identified in 8 isolates of 3 phage types, and SPTJXB003 in the remaining isolate. PFGE type did not change over time. All isolates were plasmid-free, and resistances were not transferable, either directly or by mobilization after a self-conjugative plasmid was introduced into the strains. By PCR, all isolates possessed blaCARB-2, cmlA, aadA2, sul1, and tetG but were negative for blaTEM, catI, and catIII. These results corresponded to those of the control DT104 ACSSpSuT strain P3170700. When tested for class 1 integrons, all S. Java isolates of R-type ACSSpSuT produced characteristic amplicons of 1.0 and 1.2 kb, as did P3170700, but not the drug-sensitive strain P3343110. When tested by long PCR, all 20 S. Java isolates produced a 10,041-bp fragment identical to that produced by P3170700.

PCR was used to determine whether the pentaresistant phenotype was due to the presence of the Salmonella genomic island 1 (SGI1) as previously described (5). All 20 strains produced amplicons with primers U7-L12 and LJ-R1 for the left junction and primers 104-RJ and 104-D for the right junction. These results indicate that the SGI1 in the strains of S. Java was located in the same chromosomal location as previously described for DT 104 ACSSpSuT but lacks the retronphage found to date only in DT104 strains (6).

These findings demonstrated that the ACSSpSuT resistance gene cluster in S. Java isolated from patients in the United Kingdom from 2000 to March 2003 appeared to be chromosomally located and was almost indistinguishable from that found in the epidemic clone of DT104 ACSSpSuT. This resistance gene cluster has also been identified in strains of S. Agona from poultry in Belgium (6), in a strain of S. Paratyphi B from tropical fish in Singapore (7), and a variant cluster in a strain of S. Albany from fish food from Thailand (8). It also appears to be present in isolates of S. Paratyphi B of R-type ACSSpSuT from cases of human infection in France in 2003 (F. Xavier-Weill, pers. comm.). The strains of S. Paratyphi B from Singapore and France were not tested additionally to identify the Java variant.

The strains of S. Java with chromosomally integrated ACSSpSuT resistance identified in the United Kingdom are not those associated with poultry in Germany (9) or the Netherlands (10), which have also caused infections in humans in the United Kingdom (1). The latter strains have different phage types, resistant spectrums, pulsed-field profiles, and they possess plasmid-mediated drug-resistance. However, several S. Java infections in the United Kingdom have been associated with tropical fish tanks (L.R. Ward, unpub. data), although the strain has not been isolated from this medium. A substantive increase in multiresistant S. Java has also been reported in Australia (D. Lightfoot, pers. comm.). The antibiogram of these isolates are indistinguishable from the isolates of R-type ACSSpSuT made in the United Kingdom.

These results suggest either a common origin of the ACSSpSuT-resistance gene cluster in epidemic multiresistant DT104 and multiresistant S. Java or the horizontal transfer of the cluster from DT104 to other Salmonella serovars with a worldwide distribution. In either event, the increasing occurrence of the DT104 resistance gene cluster in potentially epidemic serovars other than S. Typhimurium DT104 is concerning.

John Threlfall*Comments to Author , Belkis Levent†, Katie L. Hopkins*, Elizabeth de Pinna*, Linda R. Ward*, and Derek J. Brown‡
Author affiliations: *Health Protection Agency, London, England; †Refik Saydam National Hygiene Center, Ankara, Turkey; ‡Scottish Salmonella Reference Laboratory, Glasgow, Scotland

References

  1. Threlfall EJ. Epidemic Salmonella typhimurium DT 104 — a truly international multiresistant clone. J Antimicrob Chemother. 2000;46:710. DOIPubMed
  2. Ridley A, Threlfall EJ. Molecular epidemiology of antibiotic resistance genes in multiresistant epidemic Salmonella typhimurium DT104. Microb Drug Resist. 1998;4:1138. DOIPubMed
  3. Briggs CE, Fratamico PM. Molecular characterization of an antibiotic resistance gene cluster of Salmonella typhimurium DT 104. Antimicrob Agents Chemother. 1999;43:8469.PubMed
  4. Walker RA, Lindsay E, Woodward MJ, Ward LR, Threlfall EJ. Variation in clonality and antibiotic resistance genes among multiresistant Salmonella enterica serotype Typhimurium phage type U302 (MR U302) from humans, animals and foods. Microb Drug Resist. 2001;7:1321. DOIPubMed
  5. Boyd DA, Peters GA, Ng L-K, Mulvey MR. Partial characterisation of a genomic island associated with the multidrug resistance region of Salmonella enterica Typhimurium DT104. FEMS Microbiol Lett. 2000;189:28591. DOIPubMed
  6. Boyd D, Cloeckaert A, Chaslus-Dancla E, Mulvey MR. Characterisation of variant Salmonella genomic island 1 multidrug resistance regions from serovars Typhimurium DT104 and Agona. Antimicrob Agents Chemother. 2002;46:171422. DOIPubMed
  7. Meunier D, Boyd D, Mulvey MR, Baucheron S, Mammina C, Nastasi A, Salmonella enterica serotype Typhimurium DT 104 antibiotic resistance genomic island 1 in serotype Paratyphi B. Emerg Infect Dis. 2002;8:4303.PubMed
  8. Doublet B, Lailler R, Meunier D, Brisabois A, Boyd D, Mulvey M, Variant Salmonella genomic island 1 antibiotic resistance gene cluster in Salmonella enterica serovar Albany. Emerg Infect Dis. 2003;9:58591.PubMed
  9. Miko A, Guerra B, Schroeter A, Dorn C, Helmuth R. Molecular characterization of multiresistant d-tartrate-positive Salmonella enterica serovar Paratyphi B isolates. J Clin Microbiol. 2002;40:318491. DOIPubMed
  10. Van Pelt W, van der Zee H, Wannet WB, van de Giessen AW, Mevius DJ, Bolder NM, Explosive increase of Salmonella Java in poultry in the Netherlands; consequences for public health. Eurosurveillance. 2003;8:315.PubMed

Suggested citation for this article: Threlfall EJ, Levent B, Hopkins KL, de Pinna E, Ward LR, Brown DJ. Multidrug-resistant Salmonella Java [letter]. Emerg Infect Dis [serial on the Internet]. 2005 Jan [date cited]. Available from http://wwwnc.cdc.gov/eid/article/11/1/03-1092.htm

DOI: 10.3201/eid1101.031092

Related Links

Top of Page

Table of Contents – Volume 11, Number 1—January 2005

Comments to the Authors

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

John Threlfall, Health Protection Agency, Laboratory of Enteric Pathogens, Centre for Infections, 61 Colindale Avenue, London NW9 5HT, England; fax: +44 (0)208905 9929





characters(s) remaining.

Comment submitted successfully, thank you for your feedback.

Comments to the EID Editors

Please contact the EID Editors via our Contact Form.

 

Past Issues

Select a Past Issue:

Art in Science - Selections from Emerging Infectious Diseases
Now available for order



CDC 24/7 – Saving Lives, Protecting People, Saving Money. Learn More About How CDC Works For You…

USA.gov: The U.S. Government's Official Web PortalDepartment of Health and Human Services
Centers for Disease Control and Prevention   1600 Clifton Rd. Atlanta, GA 30333, USA
800-CDC-INFO (800-232-4636) TTY: (888) 232-6348 - Contact CDC–INFO