Shigellosis Case Study

2.2.6 Antibiotic resistance

Wide spread resistance to first line of antimicrobials has complicated the selection of drugs for the treatment of shigellosis. Sulphonamides were first introduced in the early 1940s and all Shigella strains were sensitive to this drug. In 1940s, tetracycline followed by chloramphenicol, were recommended for the treatment of shigellosis because sulphonamides became ineffective. Soon, resistance to these two drugs was observed and ampicillin and co-trimoxazole came to the rescue and were found to be clinically highly effective (Ross et al., 1972; Nelson et al., 1976). However, during the epidemic in 1980s in Eastern India, S. dysenteriae type 1 strains isolated were reported to be resistant to most of the antibiotics

Hand washing with plenty of water and soap is the most important single effective preventive strategy against shigellosis. It is emphasized that hands should be washed before eating, before feeding children, after defecation and after disposal of children’s excreta. Severe dehydration is uncommon in shigellosis; the first consideration in treating any diarrheal disease is correction of abnormalities that result from isotonic dehydration, metabolic acidosis and significant potassium loss. The oral rehydration treatment developed by the World Health Organization has proven effective and safe in the treatment of acute diarrhea, provided that the patient is not vomiting or in shock from severe dehydration. In the latter case, intravenous fluid replacement is required until initial fluid and electrolyte losses are corrected. With proper hydration, shigellosis is generally a self-limiting disease, and the decision to prescribe antibiotics is predicated on the severity of disease, the age of the patient, and the likelihood of further transmission of the infection. Effective antibiotic treatment reduces the average duration of illness from approximately 5-7 days to approximately 3 days and also reduce the period of Shigella excretion after symptoms subside. Shigellosis can usually be treated with antibiotics. The antibiotics commonly used are ampicillin, trimethoprim/sulfamethoxazole (Bactrim or Spectra), nalidixic acid, ciprofloxacin and the fluroquinolone. Appropriate treatment kills the bacteria present in the gastrointestinal tract and shortens the course of the illness (Lectures in Microbiology by Kenneth Todar). Quinolones were highly effective drug for the treatment of shigellosis. WHO