DNA-SEQUENCES IDENTICAL TO PNEUMOCYSTIS-CARINII F-SP CARINII AND PNEUMOCYSTIS-CARINII F-SP HOMINIS IN SAMPLES OF AIR SPORA

Samples of ambient air collected with three different types of spore t raps in a rural location were examined for the presence of Pneumocysti s carinii by screening for P, carinii-specific DNA sequences by DNA am plification. Eleven spore trap samples were analyzed by nested PCR, us ing oligonucleotide primers designed for the gene encoding the mitocho ndrial large subunit rRNA of P. carinii f. sp. carinii and P, carinii f. sp. hominis. The samples were collected over a 3-year period during the months of May to September, with a range of sampling times from 9 to 240 h, One air sample from an animal facility housing P, carinii-i nfected rats was also examined. P, carinii-specific amplification prod ucts were obtained from samples from each of the spore traps, The ampl ification products from eight air samples were cloned and sequenced, T he majority of the recombinants from each of these samples had sequenc es identical to those of P, carinii f. sp. carinii and P, carinii f. s p. hominis, and a number of clones had single-base differences. These data suggest that sequences identical to those of P, carinii f. sp, ca rinii and P, carinii f. sp. hominis can be detected in samples of air collected in a rural location and that P; carinii may be a component o f the air spora of rural Oxfordshire.