Ciprofloxacin Susceptibility in Salmonella enterica | CDC EID

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Volume 17, Number 1–January 2011
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Foreign Travel and Decreased Ciprofloxacin Susceptibility in Salmonella enterica Infections

Manar Al-Mashhadani, Robert Hewson, Roberto Vivancos, Alex Keenan, Nick J. Beeching, John Wain, and Christopher M. Parry Comments to Author

Author affiliations: University of Liverpool, Liverpool, UK (M. Al-Mashhadani, R. Hewson, C.M. Parry); Health Protection Agency Moorgate Point, Liverpool (R. Vivancos, A. Keenan); University of Manchester, Manchester, UK (R. Vivancos); Liverpool School of Tropical Medicine, Liverpool (N.J. Beeching); and Health Protection Agency Colindale, London, UK (J. Wain)

Suggested citation for this article

Abstract
To determine antimicrobial drug resistance patterns, we characterized nontyphoidal Salmonella enterica strains isolated in Liverpool, UK, January 2003 through December 2009. Decreased susceptibility to ciprofloxacin was found in 103 (20.9%) of 492 isolates. The lower susceptibility was associated with ciprofloxacin treatment failures and with particular serovars and phage types often acquired during foreign travel.

Nontyphoidal Salmonella enterica (NTS) isolates produce a common food-related infection that causes mild and self-limiting diarrhea and, occasionally, a potentially fatal invasive disease with bacteremia and endovascular infection (1). Antimicrobial drug therapy, often with the fluoroquinolone ciprofloxacin, is required for treating invasive NTS infections and severe diarrhea in immunocompromised patients. Full resistance to fluoroquinolones is relatively uncommon for NTS infections, but decreased susceptibility to ciprofloxacin (DCS), defined as MIC 0.1–1.0 μg/mL, has become common (2). Resistance to nalidixic acid is often used as a marker for DCS, although the validity of this assumption has been debated (3), and some have suggested that the ciprofloxacin disk susceptibility zone size breakpoints should be changed to detect such strains (2).

DCS is associated with ciprofloxacin treatment failures in patients with typhoid fever (4) and probably with invasive NTS infection, although the clinical significance of DCS in NTS has not been widely explored (5–7). Clinical clues to the presence of DCS in S. enterica infections could guide early empirical prescription of antimicrobial drug therapy. Links between DCS and foreign travel have been suggested in reports from Denmark (8) and Finland (9,10). In this study, we characterized the resistance patterns of NTS strains isolated in Liverpool and explored the value of nalidixic acid–resistance testing, the clinical significance of DCS, and possible links between DCS and foreign travel.

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Ciprofloxacin Susceptibility in Salmonella enterica | CDC EID


Suggested Citation for this Article

Al-Mashhadan M, Hewson R, Vivancos R, Keenan A, Beeching NJ, Wain J, et al. Foreign travel and decreased ciprofloxacin susceptibility in Salmonella enterica infections. Emerg Infect Dis [serial on the Internet]. 2011 Jan [date cited]. http://www.cdc.gov/EID/content/17/1/123.htm

DOI: 10.3201/eid1701.100999

Comments to the Authors

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

Christopher M. Parry, Department of Medical Microbiology and Genitourinary Medicine, School of Infection and Host Defence, Duncan Bldg, University of Liverpool, Daulby St, Liverpool L69 3GA, UK; email: cmparry@liverpool.ac.uk