Genotypes of clustered cases of Pneumocystis carinii pneumonia

Reports of outbreaks of Pneumocystis carinii pneumonia (PCP) among human im munodeficiency virus-negative immunocompromised patients have suggested a p erson-to-person transmission of P, carinii, In this study, 17 bronchoalveol ar lavage isolates from patients in 3 PCP outbreaks were genotyped, 2 in re nal transplant recipients and 1 outbreak among patients with haematological disorders. Genotypes in the P, carinii sp. f. hominis (P. carinii f,sp. ho minis) mt large subunit ribosomal RNA site 85 were detected by 2 methods: d irect sequencing and 3 different allele-specific polymerase chain reaction assays. Although limited data on patient contacts were available, the detec ted P, c, hominis genotypes do not support person-to-person transmission as the predominant transmission route of P, carinii in humans.