Norfloxacin and Azithromycin for Treatment of Nontyphoidal Salmonella Carriers

Abstract

There has been inadequate evaluation of an antibiotic for eradication of nontyphoidal salmonellae (NTS) in asymptomatic carriers. In a randomized, placebo-controlled trial, such efficacy was evaluated using 2 five-day regimens (norfloxacin, 400 mg twice per day, and azithromycin, 500 mg once per day) compared with placebo. The study included 265 food workers in an area of Thailand where NTS are endemic who were asymptomatic NTS carriers. The presence of NTS in stool samples was assessed on days 7, 30, 60, and 90 after start of treatment. At each assessment visit, <4% of participants in each of the 3 groups carried an initial Salmonella serotype; 16%-35% had new Salmonella serotypes detected, except on day 7 in the azithromycin group, when the rate was 4%. Sanitation was good at work but not at home. Selection of multidrug-resistant Salmonella enterica serotype Schwarzengrund was demonstrated. The study regimens were not better than placebo for treatment of asymptomatic food workers who carried NTS in an area where these organisms are endemic, and use of the regimens resulted in antimicrobial resistance.

Multidrug-resistantSalmonellaTyphimurium in Four Animal Facilities

“…Fluoroquinolone antimicrobial therapy did not eliminate fecal shedding of susceptible strains of salmonellae in 3 cats and 1 person from whom follow-up cultures were obtained. This finding is similar to other results in humans, which demonstrate that fluoroquinolone treatment is associated with longer duration of carriage (28). …”

Non-typhoidal Salmonella in Children: Microbiology, Epidemiology and Treatment

“…In adults with chronic carriage, norfloxacin and azithromycin were no better than placebo in eradicating carriage and were associated with higher rates of re-infection and selection of drugresistant isolates in endemic areas [69]. However, although antibiotics have been shown to prolong NTS excretion, this paradoxical finding may only be relevant following treatment of acute NTS infection.…”

Salmonella enterica Serovar Typhimurium Skills To Succeed in the Host: Virulence and Regulation

“…These carriers are characterized by a symptom-free condition and can act as reservoirs and hence contribute to the propagation of the disease, which is particularly important in the case of food workers. Unfortunately, there is a scarcity of results concerning the immune response and the efficacy of antimicrobial treatment in these silent infections that could be used to develop suitable prophylactic and therapeutic modalities (34)(35)(36).…”