We developed and studied a molecular typing approach for Campylobacter spp. with restriction fragment length polymorphism (RFLP) analysis of the flagellin geneflaA in C. jejuni. Using polymerase chain reaction, we amplified theJfaA gene from strains comprising different HL:O serotypes by using a primer set directed at the conserved 5' and 3'flaA gene sequence to generate a 1.7-kb amplicon. The amplicon was further digested with the restriction enzyme DdeI, and the fragments generated were analyzed by agarose gel electrophoresis. In 43 non-outbreak strains of six common HL serotypes (HL 1, 2, 4, 5, 9, and 36) in the United States, 18 RFLP patterns were observed. In U.S. outbreak strains previously studied by 10 other typing methods, faA typing correlated with the HL serotype within each outbreak, and six additionalflaA types were identified. Our results suggest that RFLP analysis of theflaA gene from Campylobacter spp. has sufficient discrimination to be useful as a practical typing method for clinical and epidemiologic investigations.

Pittsburgh pneumonia agent (PPA) was recently cultivated from infected egg yold on charcoal yeast extract agar. PPA has now been isolated both from infected egg yolk and human lung tissue on charcoal yeast extract agar and on a new medium, buffered charcoal yeast extract agar. PPA resembles Legionella pneumophila and other Legionella-like organisms in requirements for growth and composition of fatty acids. It differs in genetic relatedness, antigenic composition, and colonial morphology and has distinctive characteristics that allow it to be identified. The name Legionella pittsburgensis species nova is proposed for this organism.

Campylobacter jejuni is the most common enteric pathogen isolated from university and college students in the United States. During the fall and winter quarters of the 1983-1984 academic year, the authors conducted a case-control study at the University of Georgia, Athens, Georgia, to identify risk factors for C. jejuni enteritis. Students with diarrhea whose cultures yielded C. jejuni were compared with controls matched by age, sex, and residence. A total of 45 case-control pairs were interviewed about exposures during the week before the case's onset of illness. The infections occurred sporadically and were caused by a wide variety of C. jejuni serotypes. Three risk factors were identified: eating fully cooked chicken, eating chicken reported to be raw or undercooked, and contact with a cat or kitten. No case reported drinking raw milk. No significant association was found between illness and the places where chicken meals were prepared or the specific manner in which chicken was cooked. Chicken may be the principal vehicle of transmission for sporadic Campylobacter enteritis among college students.