Twenty‐six years of enteric fever in Australia: an epidemiological analysis of antibiotic resistance

• Published in: Medical journal of Australia 2012-03, Vol.196 (5), p.332-336
• Main Authors: Commons, Robert J, McBryde, Emma, Valcanis, Mary, Powling, Joan, Street, Alan, Hogg, Geoff
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Aged; Aged, 80 and over; Anti-Bacterial Agents - pharmacology; Asia, Southeastern; Australia - epidemiology; Bacterial diseases; Bacterial diseases of the digestive system and abdomen; Biological and medical sciences; Child; Child, Preschool; Drug Resistance, Bacterial; Drug Resistance, Multiple, Bacterial; Epidemiology; Female; General aspects; Human bacterial diseases; Humans; Incidence; Infant; Infant, Newborn; Infectious diseases; Logistic Models; Male; Medical sciences; Microbial Sensitivity Tests; Middle Aged; Nalidixic Acid - pharmacology; Public health. Hygiene; Public health. Hygiene-occupational medicine; Retrospective Studies; Salmonella typhi - drug effects; Salmonella typhi - isolation & purification; Statistics, epidemiology and research design; Typhoid Fever - epidemiology; Typhoid Fever - microbiology; Young Adult
• ISSN: 0025-729X; 1326-5377
• DOI: 10.5694/mja12.10082

Objectives: To determine incidence and trends in antibiotic resistance in Australian Salmonella enterica subspecies enterica serovars Typhi (S. Typhi) and Paratyphi (S. Paratyphi) isolates over the past 26 years. Design: A retrospective analysis of consecutive microbiologically confirmed enteric fever isolates. Participants and setting: All S. Typhi and S. Paratyphi isolates from patients diagnosed with enteric fever in Australia between 1985 and 2010. Main outcome measures: Incidence and variation in antibiotic resistance over time and according to country of origin. Results: We analysed 2551 isolates, which originated from 74 countries or regions, mainly India (33%) and Indonesia (22%). The incidence among Australian residents increased from four to five before 2003 to seven cases per million person‐years after 2003. Multidrug resistance (chloramphenicol, ampicillin, trimethoprim) and nalidixic acid resistance emerged rapidly from the early 1990s, with nalidixic acid resistance increasing to 70% in 2009–2010, while multidrug resistance was relatively stable at between 4% and 11%. Nalidixic acid and multidrug resistance rates are highest in isolates from the Indian subcontinent. Some countries in South‐East Asia, such as Indonesia, had very low rates of resistance; however, this varied across the region. Conclusions: Nalidixic acid resistance has become widespread in enteric fever isolates from the Indian subcontinent and some parts of South‐East Asia, justifying the use of ceftriaxone or azithromycin rather than ciprofloxacin as first‐line treatment. However, resistance in some countries remains rare, potentially allowing treatment to be adjusted according to country of origin.