Antimicrobial resistance in typhoidal and nontyphoidal salmonellae.
OBJECTIVE
Increasing occurrence of antimicrobial resistance in both typhoidal and nontyphoidal salmonellae is a major public health problem. Recent studies documenting the occurrence and types of resistance, with particular reference to quinolones and extended spectrum cephalosporins, and new approaches to treatment are reviewed.


RESULTS
Community and hospital-based studies in different Asian and African countries show widely variable rates of resistance in Salmonella enterica serovars Typhi and Paratyphi A. Occurrence of multidrug resistance has declined in some areas, but the incidence of decreased ciprofloxacin susceptibility has reached high levels, particularly in the Indian subcontinent, and isolates with full resistance to this antimicrobial are increasingly reported. Similar variability in resistance rates occurs among nontyphoidal salmonellae, with variation between serovars and by region. There are reports of plasmid-mediated qnr genes and a variety of extended spectrum cephalosporin resistance genes in nontyphoidal serovars. Two randomized controlled trials report gatifloxacin as a potential treatment option in enteric fever caused by multidrug-resistant isolates with decreased ciprofloxacin susceptibility.


CONCLUSIONS
Patterns of resistance in Salmonella are constantly changing. Continual surveillance of resistance levels is critical for clinicians to keep abreast of treatment options, but it is often lacking in resource-poor regions of the world with the highest disease burden.
Parry
Christopher M
CM
Division of Medical Microbiology and Genitourinary Medicine and The National Centre for Zoonosis Research, Faculty of Medicine, University of Liverpool, Liverpool, UK. cmparry@liverpool.ac.uk
Threlfall
E J
EJ
D000890:Anti-Infective Agents / Q000627:therapeutic use*; D004352:Drug Resistance, Microbial; D006801:Humans; D012480:Salmonella Infections / Q000188:drug therapy* / Q000382:microbiology*; D019779:Salmonella enterica / Q000187:drug effects / Q000235:genetics; D012485:Salmonella typhi / Q000187:drug effects / Q000302:isolation & purification; D014435:Typhoid Fever / Q000188:drug therapy* / Q000382:microbiology
D000890:Anti-Infective Agents