Archived Comments for:
First observation in a non-endemic country (Togo) of Penicillium marneffei infection in a human immunodeficiency virus-infected patient: a case report
To be blunt, the central premise of this report is seriously flawed. The authors claim to have isolated P. marneffei from an AIDS patient in Togo who had never visited the established and delimited endemic region. If true, this would suggest that the fungus resides elsewhere in the world – a fact that has not been established in the nearly 55 years since this organism was discovered. Unfortunately, the authors do not unequivocally prove they have isolated P. marneffei from this patient. While I realize that resources might have been limited to these investigators, the conclusions they state rely on very dubious observations. They point to the isolation of a fungus that does have a Penicillium-like appearance and that produces a red pigment (actually pink in their photographs) after two weeks of growth. Penicillium marneffei does indeed secrete a red pigment (blood red), but does so within 48-96 hours of inoculation onto growth media. However, several species of Penicillium secrete a red/pink pigment. Thus, pigment production is not a diagnostic metric easily used with P. marneffei. The authors also cite several physical symptoms of the patient. However, these can be commonly found in infections caused by various microbes.
What is truly missing in this manuscript is “proof positive” that the isolate is P. marneffei. Several key lines of evidence were not obtained including the following: 1) histopathology showing fission yeasts in tissue [P. marneffei is a dimorphic fungus that grows as a mold at room temperature, but as a fission yeast at body temperature]; 2) simple culture experiments whereby growth of the fungus at 37C results in the formation of a fission yeast morphology; and 3) PCR-based identification. These are just a few of the methods that would be required to prove that the isolate is P. marneffei. Other methods could have been employed as well (e.g., serological tests for Mp1).
In summary, at best, the authors have shown that they have isolated a species of Penicillium associated with infection of an AIDS patient. This, in itself, is interesting since Penicillium species, with the exception of P. marneffei, rarely cause infections in AIDS populations despite the ubiquity of members of this genus in nature. To my knowledge, the published literature lists less than ten cases of serious infections by non-marneffei species of Penicillium since the advent of the HIV era.
Positive Proof of Etiological Agent is Absent
25 March 2014
To be blunt, the central premise of this report is seriously flawed. The authors claim to have isolated P. marneffei from an AIDS patient in Togo who had never visited the established and delimited endemic region. If true, this would suggest that the fungus resides elsewhere in the world – a fact that has not been established in the nearly 55 years since this organism was discovered. Unfortunately, the authors do not unequivocally prove they have isolated P. marneffei from this patient. While I realize that resources might have been limited to these investigators, the conclusions they state rely on very dubious observations. They point to the isolation of a fungus that does have a Penicillium-like appearance and that produces a red pigment (actually pink in their photographs) after two weeks of growth. Penicillium marneffei does indeed secrete a red pigment (blood red), but does so within 48-96 hours of inoculation onto growth media. However, several species of Penicillium secrete a red/pink pigment. Thus, pigment production is not a diagnostic metric easily used with P. marneffei. The authors also cite several physical symptoms of the patient. However, these can be commonly found in infections caused by various microbes.
What is truly missing in this manuscript is “proof positive” that the isolate is P. marneffei. Several key lines of evidence were not obtained including the following: 1) histopathology showing fission yeasts in tissue [P. marneffei is a dimorphic fungus that grows as a mold at room temperature, but as a fission yeast at body temperature]; 2) simple culture experiments whereby growth of the fungus at 37C results in the formation of a fission yeast morphology; and 3) PCR-based identification. These are just a few of the methods that would be required to prove that the isolate is P. marneffei. Other methods could have been employed as well (e.g., serological tests for Mp1).
In summary, at best, the authors have shown that they have isolated a species of Penicillium associated with infection of an AIDS patient. This, in itself, is interesting since Penicillium species, with the exception of P. marneffei, rarely cause infections in AIDS populations despite the ubiquity of members of this genus in nature. To my knowledge, the published literature lists less than ten cases of serious infections by non-marneffei species of Penicillium since the advent of the HIV era.
Chester R. Cooper, Jr., Ph.D.
Professor, Biological Sciences
Youngstown State University
Youngstown, Ohio USA
Competing interests
None