Occurrence of Vibrio cholerae serogroups other than O1 and O139 in Austria

From 2000 to 2005, 13 infections due to non- O1/non-O139 Vibrio cholerae were documented in Austria. Twelve patients (8 years to 65 years old; 7 male) had symptomatic infections: diarrhea x 5, otitis x 6, septicemia once. All 5 patients who acquired their infections abroad, suffered from diarrhea. The 8 persons without travel history outside of Austria had otitis media (n = 4) or otitis externa (n = 2); the lethal case of septicemia affected a fisherman with underlying malignancy. One isolate was from an asymptomatic child. Detailed data on travel history inside Austria was available for 5 of these 8 patients: all 5 had visited or lived near Austria's largest lake. The concentration of salt in this westernmost steppe lake in Europe is approximately one- twentieth of that of sea water. Why otitis and not diarrhea is the dominating manifestation of non- O1/non-O139 infection acquired in Austria remains to be elucidated. We hypothesize that diarrhea due to Vibrio cholerae serogroups other than O1 and O139 acquired in Austria may simply be unrecognized by the standard operating procedures employed in clinical microbiology laboratories. Testing for Vibrio cholerae is not considered necessary for domestically acquired diarrhea. Only in patients who acquired diarrhea abroad, do physicians sometimes consider cholera as a differential diagnosis, thereby prompting the laboratory to use thiosulfate citrate bile salt sucrose (TCBS) agar plates.