Disseminated Cryptococcosis Complicating Severe SARS-CoV-2 Infection

Round 1

Reviewer 1 Report

The authors present a case of secondary infection caused by Cryptococcus in a severe SARS-CoV-2 infected patient, which highlights the attention in the increased susceptibility of acquiring invasive fungal infections due to a disregulation of the immune system caused by the viral infection. 

Please refer to the following:

1. Please check italics in scientific names along the manuscript
2. Lane 55, please correct the sentence: 

   Unfortunately, the outcome was poor and the patient died five after blood isolation of 55 Cryptococcus neoformans

3. Figure 1 needs to be referenced in the text
4. Please mention in the case description, if cryptococcal antigen was detected on serum samples, and if so, the titers?
5. Lane 101, "GXMcan", please separate words
6. Lane 106, authors mention:

   "On day 21, we noted a peak of IL-6 at the cryptococcemia diagnosis. IL-6 may have 106 been lower the previous day because of the high dosage of steroids employed in respira-107 tory failure in SARS-CoV-2 infections"

   However, according to the information on Table 1, missing data on IL-6 values on day 14 and 21; therefore, this needs to be revised
7. As authors mention in the discussion section, capsule components may induce IL-6 to be produced; can the authors include the quantification of cryptococcal antigen, and relate theses findings to the IL-6 data reported.

Author Response

The authors present a case of secondary infection caused by Cryptococcus in a severe SARS-CoV-2 infected patient, which highlights the attention in the increased susceptibility of acquiring invasive fungal infections due to a disregulation of the immune system caused by the viral infection. 

Dear Reviewer, thanks for your comments and suggestions.

Please refer to the following:

1. Please check italics in scientific names along the manuscript

Dear reviewer thank you for this comment. We have checked italics throughout the manuscript

1. Lane 55, please correct the sentence: Unfortunately, the outcome was poor and the patient died five blood isolation of 55 Cryptococcus neoformans

Dear reviewer thank you for this comment. We have corrected the text according to your suggestions.

1. Figure 1 needs to be referenced in the text

Dear reviewer thank you for this comment. We have corrected the text according to your suggestions.

1. Please mention in the case description, if cryptococcal antigen was detected on serum samples, and if so, the titers?

The diagnosis was confirmed with a positive qualitative serum antigen on the latex agglutination system (CALAS ®- Meridian Bioscience). We have not done a quantitative test, so we do not have titres of the serum cryptococcal antigen, despite that our test defines a high positivity (3+/4+).

1. Lane 101, "GXMcan", please separate words

Dear reviewer thank you for this comment. We have corrected the text according to your suggestions

1. Lane 106, authors mention:

"On day 21, we noted a peak of IL-6 at the cryptococcemia diagnosis. IL-6 may have 106 been lower the previous day because of the high dosage of steroids employed in respira-107 tory failure in SARS-CoV-2 infections"

However, according to the information on Table 1, missing data on IL-6 values on day 14 and 21; therefore, this needs to be revised

We revised this point: the peak was on day 28, not 21, there was a mistake in the written part not in Table 1. 

1. As authors mention in the discussion section, capsule components may induce IL-6 to be produced; can the authors include the quantification of cryptococcal antigen, and relate theses findings to the IL-6 data reported.

Unfortunately, as previously said, we have not performed a quantitative cryptococcal antigen. We have only performed a qualitative test which was positive on day 28. The correlation between IL-6 and the value of serum cryptococcal antigen is sure of interest, but sadly, we lack this information. 

Reviewer 2 Report

The authors presented a case of cryptococcemia in a patient suffering a COVID-19 infection.

There are some mistakes:

1. Cryptococcus, Cryptococcus neoformans, Cryptococcus gattii should be written in italics. See the whole text
2. Both Cryptococcus neoformans and Cryptococcus gattii are species complex. (Introduction, line 28)
3. Instead of administrated it should be “administered” (case presentation, line 41)
4. Instead of has deteriorated, it should be “had deteriorated” (case presentation, line 44)
5. Line 55: it says died five after?? Do you mean five days after?
6. Reference 14: The last name is González (not Gonzaàlez)

I have some questions:

1. How did you identify Cryptococcus species? Was the isolated strain genotyped? It would be an important information taking into account that neoformans var. neoformans (VNIV) has a different geographical distribution than C. neoformans var. grubii or C. gattii complex in Europe. (See Cogliati M. et al Environmental Microbiology 2017; 19: 4318-4325)
2. Have you performed lumbar punction in order to rule out central nervous system involvement? In many cases cryptococcal meningitis is almost asymptomatic.
3. Did you perform cryptococcal antigen detection (by LFA or Latex agglutination)?
4. Have you studied a respiratory samples to detect cryptococcal respiratory compromise?

Some comments:

Other cases of COVID-19-associated cryptococcosis have been published in addition to those mentioned by the authors. (Ex. a. Ther Adv Infectious Dis 2022, Vol. 9: 1–10: Missed opportunities to identify cryptococcosis in COVID-19 patients: a case report and literature review; b. Actualizaciones en sida e infectología. Buenos Aires. marzo 2021. volumen 29. número 105: 6-16: Infecciones fúngicas en pacientes con COVID-19).

Also, there is a large literature of cryptococcosis in HIV-negative patients.

Author Response

1. How did you identify Cryptococcus species? Was the isolated strain genotyped? It would be an important information taking into account that neoformans var. neoformans (VNIV) has a different geographical distribution than C. neoformans var. grubii or C. gattii complex in Europe. (See Cogliati M. et al Environmental Microbiology 2017; 19: 4318-4325)

The characterization of cryptococcal subspecies has been made with VITEK® 2 (bioMérieux).

1. Have you performed lumbar punction in order to rule out central nervous system involvement? In many cases cryptococcal meningitis is almost asymptomatic.

No lumbar punction has been performed to rule out the CNS involvement due to the critical condition of our patient and the rapid evolution of the disease. The patient died five days after the blood isolation of Cryptococcus neoformans and there has been no time to obtain a CSF sample.

1. Did you perform cryptococcal antigen detection (by LFA or Latex agglutination)?

The diagnosis was confirmed with positive serum antigen on latex agglutination system (CALAS ®- Meridian Bioscience)

1. Have you studied a respiratory sample to detect cryptococcal respiratory compromise?

No respiratory samples have been analysed. Bronchoalveolar lavage was not performed for some reasons of the previous question.

Some comments:

Other cases of COVID-19-associated cryptococcosis have been published in addition to those mentioned by the authors. (Ex. a. Ther Adv Infectious Dis 2022, Vol. 9: 1–10: Missed opportunities to identify cryptococcosis in COVID-19 patients: a case report and literature review; b. Actualizaciones en sida e infectología. Buenos Aires. marzo 2021. volumen 29. número 105: 6-16: Infecciones fúngicas en pacientes con COVID-19).

We have added all Articles in the References: previously we have not cited the Articles which were already mentioned in Chestain et al review (the one you have suggested in the comments). We have included Messina et al article (Infecciones fúngicas en pacientes con COVID-19) in our manuscript, even if all of them were HIV-positive patients with median CD4+ of 13 cell/ul, which is a major confounding factor and SARS-CoV-2 role in the pathogenesis it’s not clear.

Also, there is a large literature of cryptococcosis in HIV-negative patients.

We added some literature on cryptococcosis in HIV-negative, immunocompetent patients.