Bacteriology of histopathologically defined appendicitis in children

Background. Acute appendicitis is the most common surgical emergency in chi ldhood. However, the pathogenesis and detailed microbiology are obscure. Objective. To determine in detail the bacterial etiology of appendicitis in children in relation to the histologic tissue pathology. Study design. Tissue samples obtained at surgery from 41 children with susp ected acute appendicitis were examined histologically and by culture for ae robic and anaerobic bacteria. The patients were analyzed according to histo pathologic and clinical findings. Results. Aerobic and anaerobic species were isolated from 40 of 41 (98%) sa mples; on average, 14.1 isolates per specimen (10.4 anaerobes and 3.7 aerob es). Specimens from patients with gangrenous appendices yielded significant ly higher numbers of anaerobic isolates per specimen than did specimens fro m patients with healthy appendices (11.7 us. 7.7; P < 0.01). Bacteria belon ging to the Bacteroides fragilis group were the most frequently isolated an aerobic microorganisms (95%). Other organisms frequently isolated in all hi stology groups were Peptostreptococcus micros (66%), Bilophila wadsworthia (63%), Fusobacterium nucleatum (44%), Eggerthella lenta (44%) and a hithert o undescribed bile-resistant, pigment-producing Gram-negative rod (41%). Of the aerobes Escherichia coli (88%) and Streptococcus anginosus group (form er Streptococcus "milleri " group) organisms (61%) were the most frequent f indings. Conclusions. The shift from histologically normal toward gangrenous appendi ces was clearly associated with markedly elevated anaerobic bacterial count s in terms of species. The unusually high frequencies of B. wadsworthia (75 %) and the hitherto undescribed bile-resistant, pigment-producing Gram-nega tive rod (56%) in gangrenous appendices represent unique and different find ings from those reported in adults.