From the Guidelines
Chronic Salmonella carriers should be treated with a 4-6 week course of ciprofloxacin (500-750mg twice daily) or other fluoroquinolones, as this has shown high efficacy rates for decolonization, particularly for Salmonella serovar Typhi carriers. Asymptomatic shedding of Salmonella serovar Typhi after acute infection is quite common, and can persist beyond a year in a small percentage of patients 1. These chronic carriers can spread infection to others if proper hand hygiene practices are not followed. Key considerations for managing chronic Salmonella carriers include:
- Practicing strict hand hygiene to prevent the spread of infection
- Avoiding preparing food for others
- Not working in food service or healthcare until cleared by multiple negative stool cultures
- Regular follow-up testing with stool cultures to confirm clearance of the infection The carrier state develops because Salmonella bacteria can evade the immune system by hiding within gallbladder epithelial cells or forming biofilms on gallstones, making antibiotic penetration difficult 1. In some cases, particularly for typhoidal Salmonella carriers, alternative treatments such as high-dose amoxicillin combined with probenecid may be effective, and in difficult cases, cholecystectomy may be necessary 1. However, the use of fluoroquinolones, such as ciprofloxacin, is generally recommended due to their high efficacy rates for decolonization, as shown in one small randomized, controlled trial and one nonrandomized trial 1.
From the Research
Definition and Treatment of Chronic Salmonella Carrier
- Chronic salmonella carrier is defined as the shedding of a Salmonella species for ≥ 1 year, as documented by an initial positive culture of a stool sample obtained at least 1 month after resolution of the acute illness and repeated positive cultures for at least 1 year 2.
- The treatment of chronic salmonella carrier is challenging, and regimens commonly fail, including those that combine antibiotic administration with removal of the gallbladder 3.
Antibiotic Treatment Options
- Quinolones, such as norfloxacin and ciprofloxacin, have been shown to be effective in eradicating biliary and fecal reservoirs of infection in chronic carriers of both typhoidal and nontyphoidal Salmonella strains 3, 4.
- Azithromycin is commonly used for first-line treatment of uncomplicated enteric fever, but the response to treatment may be sub-optimal in some patient groups when compared with fluoroquinolones 5.
- Ciprofloxacin has been shown to be more effective than azithromycin in treating uncomplicated Salmonella Typhi infection, with faster fever clearance times and shorter duration of bacteraemia 5.
Treatment Duration and Outcome Assessment
- Clinical trials of investigational anti-infective drugs for the treatment of the salmonella carrier state may be conducted with a placebo control or an active concurrent control, and patients should generally receive therapy for at least 6 weeks 2.
- Outcome will be assessed only by microbiological criteria, and determination of the interval required for the suppression of salmonellae and follow-up for 6 months after completion of therapy are recommended 2.