Volume 15, Number 3—March 2009
Hypothetical Pneumocystis jirovecii Transmission from Immunocompetent Carriers to Infant
The recent dispatch article by Rivero et al. reports the transmission of Pneumocystis jirovecii from immunocompetent grandparents to their granddaughter (1). The authors’ conclusion was based on 2 facts: the grandparents were carriers but neither the parents nor the child’s brother was a carrier, and the P. jirovecii genotype observed in the grandparents was identical to that found in the infant. In our opinion, the data provided by the authors do not support the conclusion that transmission has occurred. First, the 2 markers used for typing show a small number of alleles and thus provide low discrimination among isolates (2). Consequently, the P. jirovecii isolates present in the grandparents and in the infant may have been epidemiologically unrelated. Second, the frequency of occurrence of the different genotypes obtained was not investigated. The presence of the same genotype in the grandparents and in the infant may result from a high frequency of this genotype in the geographic area where the family lived. In fact, the use of a validated typing method and the analysis of unlinked control patients have proven necessary in other studies to demonstrate transmission of P. jirovecii (3–7). We believe that the reported transmission event remains a hypothesis.
- Rivero L, de la Horra C, Montes-Cano MA, Rodríguez-Herrera A, Respaldiza N, Friaza V, Pneumocystis jirovecii transmission from immunocompetent carriers to infant. Emerg Infect Dis. 2008;14:1116–8.
- Beard CB, Roux P, Nevez G, Hauser PM, Kovacs JA, Unnasch TR, Strain typing methods and molecular epidemiology of Pneumocystis pneumonia. Emerg Infect Dis. 2004;10:1729–35.
- de Boer MG, Bruijnesteijn van Coppenraet LE, Gaasbeek A, Berger SP, Gelinck LB, van Houwelingen HC, An outbreak of Pneumocystis jiroveci pneumonia with 1 predominant genotype among renal transplant recipients: interhuman transmission or a common environmental source? Clin Infect Dis. 2007;44:1143–9.
- Höcker B, Wendt C, Nahimana A, Tönshoff B, Hauser PM. Molecular evidence of Pneumocystis transmission in pediatric transplant unit. Emerg Infect Dis. 2005;11:330–2.
- Rabodonirina M, Vanhems P, Couray-Targe S, Gillibert RP, Ganne C, Nizard N, Molecular evidence of interhuman transmission of Pneumocystis pneumonia among renal transplant recipients hospitalized with HIV-infected patients. Emerg Infect Dis. 2004;10:1766–73.
- Schmoldt S, Schuhegger R, Wendler T, Huber I, Söllner H, Hogardt M, Molecular evidence of nosocomial Pneumocystis jirovecii transmission among 16 patients after kidney transplantation. J Clin Microbiol. 2008;46:966–71.
- Nevez G, Chabé M, Rabodonirina M, Virmaux M, Dei-Cas E, Hauser PM, Nosocomial Pneumocystis jirovecii infections. Parasite. 2008;15:359–65.