Medication Summary
Trimethoprim/sulfamethoxazole (TMP-SMZ) is the drug of choice for treating cyclosporiasis. A standard dose of TMP 160 mg plus SMX 800 mg (one double-strength tablet), orally, twice daily should be used. Immunocompetent patients become symptom-free within a median of 3 days. In a study of patients with AIDS in Haiti, individuals cleared the organism on average 2.5 days into treatment during a 10-day regimen. In patients with immunosuppression, a higher dose of TMP-SMZ as well as extending treatment duration to about 14 days may be necessary. [7]
Nitazoxanide, a 5-nitrothiazole derivative with broad-spectrum activity against helminths and protozoans, has been shown to be effective against C cayetanensis, with an efficacy 87% by the third dose (first, 71%; second 75%). Three percent of patients had minor side effects. Thus, nitazoxanide could be a useful alternative to patients allergic to TMP-SMZ. [17]
One small study of 20 patients with HIV compared TMP-SMZ (n = 9) with ciprofloxacin (n = 11) in the treatment of C cayetanensis infection. [38] With TMP-SMZ by day 7, diarrhea had ceased in 9 of 9 patients, and stools were negative for oocysts in all 9 patients. With ciprofloxacin by day 7, diarrhea ceased in 10 of 11 patients, and stools were negative for oocysts in 7 of 11 patients (64%). The conclusion was that, although ciprofloxacin is not as effective as TMP-SMZ, it is an acceptable alternative for patients unable to tolerate TMP-SMZ. However, this study has not been replicated, and other studies have commented that ciprofloxacin treatment did not produce a good response. The consensus among many practitioners is that ciprofloxacin may not be a satisfactory treatment for cyclosporiasis.
Results from small studies have not demonstrated norfloxacin, metronidazole, tinidazole, quinacrine, and azithromycin to be effective.
Antibiotics
Class Summary
Therapy must be comprehensive, covering all likely pathogens in the context of this clinical setting.
Trimethoprim-sulfamethoxazole (Bactrim, Bactrim DS, Septra, Septra DS)
Combination antibiotic inhibits 2 sequential steps in bacterial folate synthesis. It has a wide spectrum of activity and reduced resistance because of the combined action of 2 drugs. Most gram-positive and gram-negative organisms are sensitive. Typically resistant organisms include Pseudomonas aeruginosa, Bacteroides fragilis, and enterococci. After oral administration, TMP peaks by 2 h and SMZ by 4 h. Respective half-lives are 11 h and 10 h.
Ciprofloxacin (Cipro)
Fluorinated 4-quinolone. Broad-spectrum antimicrobial inhibits gyrase-mediated DNA supercoiling in bacteria, leading to disruption of bacterial DNA replication. Effective against many gram-positive and gram-negative organisms. Inhibits several intracellular bacteria (ie, Chlamydia, Mycoplasma, Legionella, Brucella, Mycobacterium). In one study, 1 of 7 patients administered 500 mg 3 times qwk had a recurrence after 4 wk of therapy (no recurrences with TMP-SMZ). Well-absorbed after PO administration, peaks within 1-3 h, and serum elimination half-life is 5-6 h.
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Photomicrograph of a fresh stool sample prepared with a 10% formalin solution and stained with modified acid-fast stain. This image shows four Cyclospora cayetanensis oocysts with variable staining among the four oocysts. Courtesy of CDC/DPDx - Melanie Moser [https://phil.cdc.gov/Details.aspx?pid=7827].
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Photomicrograph of a fresh stool sample prepared using a 10% formalin solution and stained with safranin. Three homogenously stained Cyclospora cayetanensis oocysts can be seen. Courtesy of CDC/DPDx - Melanie Moser [https://phil.cdc.gov/Details.aspx?pid=7828].
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Life cycle of Cyclospora cayetanensis in pictorial form. Courtesy of CDC/DPDx [https://www.cdc.gov/parasites/cyclosporiasis/biology.html].
Tables
Pattern of Spread |
Countries |
Comments |
Endemic |
Bangladesh, Brazil, Chile, China, Cuba, Dominican Republic, Egypt, Guatemala, Haiti, India, Indonesia, Jordan, Mexico, Morocco, Nepal, Nigeria, Pakistan, Peru, Puerto Rico, Romania, Saudi Arabia, Tanzania, Thailand, Turkey, Venezuela, Viet Nam, Zimbabwe |
Prevalence (1-15%†) varies significantly with the season and from year to year; children (≤ 9 y, most studies) account for 70-80% cases, which are typically asymptomatic (72-94%); asymptomatic disease is higher in older children (10-18 y) and adults (>18 y); infection rate in those with HIV is significantly higher than overall prevalence |
International travel-related |
Australia, Belgium, Czech Republic, Germany, Greece, Ireland, Italy, Japan, The Netherlands, Spain, Switzerland, United Kingdom, United States |
≤4% returning travelers with diarrhea |
Foodborne outbreaks |
Canada, United States, Germany, Mexico |
Canada/United States: raspberries, blackberries, mesclun, basil‡; Germany: lettuce imported from Southern France/Southern Italy; Mexico: watercress |
Waterborne outbreaks |
United States (Chicago), Nepal |
14 cases of cyclosporiasis; tap water in medical dormitory, suspected source was contaminated water storage tank; 12 of 14 developed cyclosporiasis |
* Community-based studies † Highest in spring and early summer ‡ Fresh produce. Raspberries, peas, or blackberries from Guatemala; mesclun (young salad greens, eg, spring mix, field greens, baby greens, gourmet salad mix) or lettuce from Peru or United States; basil from Mexico or United States. |
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