Treatment of Japanese patients with enteric fever using azithromycin and MIC levels for causative organisms.

In Japan azithromycin (AZM) has been used to treat enteric fever caused by bacteria with resistance to fluoroquinolones; however, the dose, length of treatment and effectiveness of AZM among Japanese patients with enteric fever is unclear. We studied 5 Japanese adults and 1 Japanese child with enteric fever (4 had typhoid fever and 2 had paratyphoid fever) who were treated with oral AZM. The treatment regimens were: 1,000 mg as a single or in 2 divided doses on the 1st day, followed by 500 mg as a single dose daily for 5-6 additional days, or 500 mg as a single dose daily for 10 days. The minimum inhibitory concentrations (MICs) for AZM against 5 causative organisms were investigated with an E-test. Good clinical results were observed in the 5 adult patients but treatment failure was seen in the 1 child patient with typhoid fever; no adverse reactions were found. MICs of AZM were 4 microg/ml against S. Typhi in 2 patients, 8 microg/ml against S. Typhi in 2 patients, and 32 microg/ml against S. Paratyphi A in 1 patient. Our findings indicate AZM may be a reasonable choice for treatment of Japanese adult patients with enteric fever.