In May 1993 a hospital in northwestern Saudi Arabia reported four children who developed dysentery followed by hemolytic uremic syndrome (HUS) after a visit to a village in southwestern Saudi Arabia (Gizan province). "Shigella dysenteriae" type 1 resistant to cotrimoxizole, chloramphenicol, tetracycline and ampicillin was isolated from the four children and eight other family members with diarrhea or dysentery. Health authorities in Gizan reported that they were aware of increasing reports of dysentery with HUS, but that no organism had been isolated.
Methodology
We reviewed medical records of all HUS cases in the only referral hospital in Gizan and all dysentery cases in the same time period in secondary care hospitals. We defined HUS as any dysentery case that developed acute renal failure and anemia with fragmented red cells. We compared HUS cases with dysentery cases hospitalized during the same period.
Results
We identified 23 cases of dysentery with HUS, all in children (median age 1 year) from 15 villages. The same multiply resistant "S. dysentariae" type 1 was isolated from four dysentery cases. Seventy-eight percent (18) developed HUS from 2 to 14 days after hospital admission for uncomplicated dysentery. Treatment of the dysentery with ampicillin preceded onset of HUS in 14 of the 18, compared with 34 of 73 hospitalized dysentery cases that did not develop HUS (risk ratio=3.14, 95% confidence interval =1.12-8.8). All five children who developed HUS either before or on the day of hospital admission had received oral ampicillin for 5 to 7 days before developing HUS, compared with two of nine community control children of the same age who had dysentery but were not hospitalized (odds ratio=infinite, P value=0.02, Fisher's exact test).
Conclusion
: "Shigella dysenteriae" type 1 produces a verotoxin that is known to cause HUS. The association of HUS with presumptive ampicillin treatment of dysentery suggests that treatment with antibiotics to which "S. dysenteriae" type 1 was resistant led to the development of HUS. Physicians should be cautious when treating dysentery with antibiotics unless the causative organism and the resistance pattern have been identified.