Transmission of Pneumocystis carinii DNA from a patient with P. carinii pneumonia to immunocompetent contact health care workers

Abstract

The transmission of Pneumocystis carinii from person to person was studied by detecting P. carinii-specific DNA in prospectively obtained noninvasive deep-nasal-swab samples from a child with a documented P. carinii pneumonia (PCP), his mother, two contact health care workers, and 30 hospital staff members who did not enter the patient's room (controls). Nested-DNA amplification was done by using oligonucleotide primers designed for the gene encoding the mitochondrial large subunit rRNA of rat P. carinii (P. carinii f. sp. carinii) that amplifies all forms of P. carinii and internal primers specific for human P. carinii (f. sp. hominis). P. carinii f. sp. hominis DNA was detected in samples from the patient and all of his contacts versus none of the 30 hospital staff members. The results, as previously shown in murine models of P. carinii pneumonia, document that person-to-person transmission of P. carinii is possible. This observation suggests that immunocompromised patients not on PCP prophylaxis should not enter the room of a patient with PCP, and it also raises the question as to whether healthy contacts can transmit the disease to immunocompromised patients at risk.

FIG. 1

P. carinii DNA amplification with nested PCR with primers pAZ102-E and pAZ102-H designed for the P. carinii gene encoding the mitochondrial large subunit rRNA and with primers pAZ102X and pAZ102-Y, which are internal to the first set of primers and specific for P. carinii sp. f. hominis on noninvasive respiratory samples on the index patient and contacts. (A) Top, index patient on days 1 to 34 showing the amplification product of 267 bp (positive) and no amplification product (negative) on days 41 and 48; bottom, mother positive on day 5 and negative on days 8, 12, and 15. (B) Top, attending physician positive on days 8 and 12 and negative on days 34 and 41; bottom, nurse positive on day 8. (C) Thirty noncontact staff members tested on day 34 (all negative). L, Ladder (A and B, lines 1; C, lines 1 and 19); PC, positive control (A and B, lines 11, bottom; C, line 16, bottom); NC, negative control (A and B, lines 12, bottom; C, line 18, bottom).