Common Etiologic Agents - Enteric Infections and Food Poisoning

COMMON ETIOLOGIC AGENTS

Great advances have been made in our understanding of gastrointestinal infections. Before the late 1960s, fewer than 20% of the infectious syndromes described above could belinked to a specific etiologic agent by any known diagnostic method regardless of cost.The organisms listed in Table 65 – 1 now account for 80 to 90% of cases, although diag-nostic methods for all of them are not yet practical for clinical laboratories. The primary clinical syndrome listed for each agent in Table 65 – 1 should not be regarded as absolute because there are individual variations and overlap; some pathogens cause more than onesyndrome. For example, Shigellainfections frequently go through a brief watery diarrheastage before localizing in the colon, and Campylobacter enteritis usually begins withfever, malaise, and abdominal pain, followed by dysentery. In any single case, the clinicalfindings may suggest a range of etiologic agents, but none is sufficiently specific to be di-agnostic of any single organism.