Evaluation ofAlkaline Phosphatase-Labelled ipaHProbefor Diagnosis ofShigella Infections

setting through aprospective clinical trial. Inagroup of219Peruvian adults andchildren withacute gastroenteritis, theipaHprobedetected 85%ofcases of shigeliosis anddemonstrated aspecificity of95%whencompared withsimultaneous detection byseveral stool culture techniques. Additionally, three cases ofEIECinfection whichcould notbediagnosed byculture methods alone weredetected withtheipaHprobe andwereconfirmed byplasmid analysis andSereny testing. Thesepreliminary results suggest that, withfurther research, theipaHprobe should prove tobeauseful and rapid adjunct inthediagnosis ofacute gastroenteritis indeveloping countries. Diagnostic tools fordetermining theetiology ofacute dysentery indeveloping countries provide useful information forepidemiologists andpublic health officials interested inthelocal prevalence ofpathogens aswellasforclinicians managing individual cases. Thestandard procedure foridentification ofbacterial enteropathogens hasbeenthestool culture, aprocedure withseveral practical limitations. Selection ofpathogenic bacterial colonies fromnormal colonic flora onselective culture mediacanbedifficult ifthepathogenic colonies arefeworiftheobserver isunskilled, andthe protocols forenteropathogen identification usually require 48to72h orlonger fortheir completion. Inaddition, Escherichia coli strains which causediarrhea bytheproduction ofenterotoxins (enterotoxigenic E.coli [ETEC]) orby epithelial cell invasion inamannersimilar tothat bywhich Shigella spp.causediarrhea (enteroinvasive E.coli [EIEC]) cannotbeselectively identified byroutine microbiologic methods, andspecial assays arerequired forthedetection of virulence factors bythese strains. Thedifficulty inherent in theidentification ofEIECstrains haslimited their detection inepidemiologic surveillance andindividual patient evaluations (3). DNA probes havebeenusedasanalternative diagnostic method because oftheir potential forrapid, specific diagnosis. Theycanalsobeusedtodetect thepresence ofgenetic material encoding virulence factors, allowing fortheidentification ofdiarrhea-producing E.coli orotherenteropathogensnotreadily detectable onstool culture. Recent interest