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Seasonal changes in indoor airborne fungal concentration in a hematology ward
J Infect Chemother xxx (xxxx) xxx
Contents lists available at ScienceDirect
Journal of Infection and Chemotherapy journal homepage: http://www.elsevier.com/locate/jic
Original Article
Seasonal changes in indoor airborne fungal concentration in a hematology ward* Takehiko Mori a, b, *, Taku Kikuchi a, Jun Kato a, Yuya Koda a, Masatoshi Sakurai a, Osamu Kikumi c, Rika Inose d, Mitsuru Murata e, Naoki Hasegawa b, f, Hitomi Nakayama a, Rie Yamazaki a, Shinichiro Okamoto a a
Division of Hematology, Department of Medicine, Keio University School of Medicine, Tokyo, Japan Center for Infectious Disease and Infection Control, Keio University Hospital, Tokyo, Japan Research & Development Division, Midori Anzen Co. Ltd., Tokyo, Japan d Office of Clinical Laboratory Technology, Keio University Hospital, Tokyo, Japan e Department of Laboratory Medicine, Keio University School of Medicine, Tokyo, Japan f Department for Infectious Diseases, Keio University School of Medicine, Tokyo, Japan b c
a r t i c l e i n f o
a b s t r a c t
Article history: Received 5 September 2019 Received in revised form 17 October 2019 Accepted 29 October 2019 Available online xxx
Invasive fungal disease (IFD) is an important infectious complication of hematological disorders, especially in hematopoietic stem cell transplantation recipients. Evidences suggest seasonal and/or geographical variations in the airborne fungal counts and a relationship between those counts and the incidence of IFD. We evaluated the concentrations of indoor airborne fungi quantitated over the course of one year in a hematology ward in Japan. In January, April, July, and October, fixed volumes of air samples were obtained by an air sampler in a hematology ward not equipped with a high-efficiency particulate air filter and incubated in fugal cultures. Samples were also obtained from a protective environment in the same ward and were evaluated. The number of fungal colonies per 50 L of sampled air was highest in October (median 2.25 (range, 0.2e7.0)), which was significantly higher than those in the other three months (0.1 (range, 0e1.0) in January; 0 (0-0) in April; 0.55 (0e2.5) in July; P < 0.01)). Commonly identified pathogens included Penicillium and Cladosrporium species, but Aspergillus species was detected only in July and October samples. These results suggest a seasonal variation in indoor airborne fungal concentrations in Japan, which could affect the epidemiology of IFD. © 2019 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.
Keywords: Fungus Airborne fungus Hematology ward Seasonal change Invasive fungal disease
1. Introduction Patients with hematological malignancies, especially recipients of hematopoietic stem cell transplantation (HSCT), are at high risk of developing invasive fungal disease (IFD). Against Candida species (spp.), the efficacy of prophylaxes using fluconazole and other agents has been established and widely used for these high-risk patients [1,2]. In contrast, although studies have demonstrated the efficacy of anti-mold agents such as itraconazole, voriconazole,
* All authors meet the ICMJE authorship criteria. * Corresponding author. Division of Hematology, Department of Medicine, Keio University School of Medicine 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan. E-mail address: [email protected] (T. Mori).
and posaconazole in preventing aspergillosis [1,3e5], invasive aspergillosis remains a critical life-threatening complication in these high-risk patients. A protective environment equipped with a high-efficiency particulate air (HEPA) filter has been recognized as a highly useful asset for preventing exposure to Aspergillus spp. and its use is recommended especially after allogeneic HSCT [6e8]. Geoclimatic effects on environmental airborne fungi counts and their relationship to the incidence of invasive aspergillosis after HSCT were evaluated in the United States [9] In that study, seasonal variations in outdoor airborne fungal concentrations were observed, and were found to be significantly associated with the incidence of aspergillosis. With regard to the evaluation of the indoor airborne fungal load in a hospital, a limited number of studies from different countries have shown different results, which also suggested a geoclimatic effect [10e13]. In the present study, seasonal changes in the indoor airborne fungal concentration in the
https://doi.org/10.1016/j.jiac.2019.10.020 1341-321X/© 2019 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.
Please cite this article as: Mori T et al., Seasonal changes in indoor airborne fungal concentration in a hematology ward, J Infect Chemother, https://doi.org/10.1016/j.jiac.2019.10.020
2
T. Mori et al. / J Infect Chemother xxx (xxxx) xxx
environment of a hematology ward of a university hospital in Tokyo, Japan were evaluated.
samples from the protective environment showed no significant differences among the 4 months (P ¼ 0.658, Table 1).
2. Materials and methods
3.2. Airborne fungal concentrations
2.1. Air sampling
The indoor airborne fungi were quantitatively evaluated by counting the colonies in each sample. In the nonprotective environment, the concentration of airborne fungi per 50 L sample was significantly higher in October than in the other 3 months (P < 0.00001, Fig. 1). In the protective environment, there were no significant differences in the fungal concentrations among the 4 months (P ¼ 0.522, Fig. 1). The concentrations were lower in the protective environment than in the nonprotective environment at each sampling month. The differences were significant in July and October (P < 0.001 and < 0.000001, respectively) but the significance was borderline in January and April (P ¼ 0.086 and 0.094, respectively).
All air samplings were performed at the hematology ward of Keio University Hospital (Tokyo, Japan). The ward consisted of 41 beds, including 21 beds in a high-efficiency particulate air (HEPA)filtered protective environment and 20 in a nonprotective environment. In January, April, July, and October, air samples were obtained by using a commercially available air sampler (BIOSAMP MBS-1000, Midori Anzen Co., Ltd., Tokyo, Japan) at two fixed places in the non-HEPA-filtered environment (nonprotective environment) and at two fixed places in the HEPA-filtered protective environment. The volumes of obtained air for each sampling were 50, 100, and 250 L. Sampling was performed in triplicate; that is, 9 samples were obtained at each place and at each time.
3.3. Identification of fungal species
2.2. Fungal cultures
The fungal species identified are shown in Table 2. The common isolates from the nonprotective environments were Cladosporium sp. and Penicillium sp., which were followed by Rhodotorula sp. and
Samples were collected on potato dextrose agar plates and incubated at 25 C for 4e5 days followed by 2 days at room temperature. After incubation, the identified colonies were counted. Based on the air sample volume for each plate, the numbers of colonies per 50 L air volume were compared. Each colony was examined to identify the species morphologically and micromorphologically by using Miura LCA medium and/or CHROMAgar medium as appropriate.
Number of colonies/50 L of air
7
2.3. Statistical analysis Differences in the number of positive cultures and in the number of fungal colonies were compared by using Fisher's exact test and the Friedman test, respectively. Values of P < 0.05 were considered statistically significant. All statistical analyses were performed by using EZR, a graphical user interface for R [14].
6 5 *
4 3 2 1
3. Results
**
0 3.1. Airborne fungal evaluation on sample basis
Jan
Apr
Jul
Jan
Oct
Nonprotective environment
Table 1 shows the numbers of culture samples yielding any fungal colonies from the 18 samples obtained per sampling time. In the nonprotective environment, significantly more of the October samples were positive for fungal colonies compared to the other 3 months (P < 0.01). Fewer of the samples from the protective environment were positive for fungi compared with the samples from the nonprotective environment. In contrast to the samples from the nonprotective environment, the number of positive
Apr
Jul
** Oct
Protective environment
Fig. 1. Airborne fungal concentrations in nonprotective and protective environments. In the nonprotective environment, the airborne fungal concentration was significantly higher in October than in the other 3 months (*P < 0.00001). There was no significant difference among the 4 months in the protective environment (P ¼ 0.522). The concentrations were lower in the protective environment than in the nonprotective environment at each sampling month. The differences were significant in July and October (**P < 0.001 and < 0.000001, respectively) but with borderline significance in January and April (P ¼ 0.086 and 0.094, respectively).
Table 1 Number of samples positive for fungi. January
April a
Nonprotective environment Positve Negative Protective environment Positve Negative a b
July a
October a
P value a
(N ¼ 18 )
(N ¼ 18 )
(N ¼ 18 )
(N ¼ 18 )
12 6
8 10
11 7
18 0
<0.01
3b 15
3 15
1b 17
4b 14
0.658
Nine culture samples obtained from at two places were evaluated. Significantly decreased as compared with nonprotective environment (P < 0.01, <0.001, <0.00001, respectively).
Please cite this article as: Mori T et al., Seasonal changes in indoor airborne fungal concentration in a hematology ward, J Infect Chemother, https://doi.org/10.1016/j.jiac.2019.10.020
T. Mori et al. / J Infect Chemother xxx (xxxx) xxx
3
Table 2 Identified species of airborne fungus in nonprotective and protective environments. January
April
July
October
Species
No. of colonies
Species
No. of colonies
Species
No. of colonies
Species
No. of colonies
Nonprotective environment
C. cladosporioides Penicillium sp. C. sphaerospermum Cladosporium sp. Rhodotorula sp. Phoma sp.
3 2 1 1 1 1
C. cladosporioides C. albidus Penicillium sp. R. mucilaginosa Cryptocossus sp. Unidentified (yeast)
4 2 1 1 1 1
Penicillium sp. C. sphaerospermum Cryptocossus sp. Rhodotorula sp. Arthrinium sp. Trametes sp. Cladosporium sp. Monochaetia sp. Rhinocladiellas sp A. sydowii Aspergillus sp. Unidentified (mold) Unidentified (yeast)
18 4 4 2 2 2 1 1 1 1 1 6 1
Protective environment
Cryptococcus sp. R. mucilaginosa C. sphaerospermum Unidentified (mold)
5 1 1 1
C. cladosporioides C. albidus Alternaria sp.
1 1 1
Penicillium sp.
1
Penicillium sp. C. sphaerospermum C. cladosporioides Cladosporium sp. Paecilomyces sp. C. albidus Aspergillus sp. Rhodotorula sp. A. fumigatus Aspergillus niger R. mucilaginosa Wallemia sebi Unidentified (mold) Unidentified (yeast) Penicillium sp. R. mucilaginosa
61 13 8 6 5 3 3 2 1 1 1 1 11 2 2 1
The species were identified morphologically and micromorphologically. Unidentified’ does not account for single species. C. cladosporioides, Cladosporium cladosporioides; C. sphaerospermum, Cladosporium sphaerospermum; R. mucilaginosa, Rhodotorula mucilaginosa; C. albidus, Cryptocossus albidus; A. fumigatus, Aspergillus fumigatus; A. sydowii, Aspergillus sydowii.
Cryptocossus sp. During the study period, there were no cases of IFD due to commonly isolated pathogens such as Cladosporium and Penicillium spp. Aspergillus spp. were isolated only in July and October. In the protective environment, common isolates were Cryptocossus, Cladosporium, and Penicillium spp. Aspergillus sp. was not isolated from any sampling month in the protective environment. 4. Discussion In this study, the seasonal variation of indoor airborne fungal concentrations was demonstrated in a hematology ward, with the highest concentrations observed in October. Although an epidemiological evaluation was not performed, this seasonal variation could affect the environmental risk of airborne fungal infection in an in-patient setting. Aspergillus spp. were detected only in June and October. The protective environment successfully and significantly decreased the fungal concentrations throughout the year, eliminating the seasonal variability in the concentration. Airborne molds cause life-threatening IFD in immunocompromised patients, especially those with hematological malignancies and recipients of HSCT. The inhalation of airborne fungal spores is the most likely cause of pulmonary IFD. Therefore, a protective environment, which is the most effective way to remove airborne fungal spores from the environment, has been recommended and widely used for the prophylaxis of airborne IFD [6e8]. The association between seasonal changes in environmental airborne fungi and the incidence of IFD has been demonstrated [9]. In that study, conducted in Seattle in the United States, the ‘outdoor’ environmental fungal spore concentration was significantly increased in the summer, which was significantly related to the incidence of invasive aspergillosis among HSCT recipients in that city. That was the first study to show an epidemiological effect of seasonal changes in outdoor airborne fungal concentrations on the incidence of IFD. However, it is plausible that the ‘indoor’ airborne fungal concentration would have a greater effect than the outdoor concentration on the incidence of IFD in an in-patient setting, since most high-risk patients are managed as in-patients. The seasonal variations of indoor airborne fungal concentrations in hospitals have been evaluated in several countries, including France, Mexico,
Poland, and Portugal [10e13]. Except for the study conducted in Mexico [10], these studies consistently demonstrated seasonal changes in airborne fungal concentrations in hospitals. Consistent with the results of the studies, our results showed a seasonal variation in the ‘indoor’ airborne fungal concentration in a hospital in Japan. Such seasonal variation could affect the incidence of institutional and/or regional IFD, and it should be incorporated into IFD risk assessments in the management of immunocompromised patients. The relationship between indoor airborne fungal concentration and the incidence of IFD at each institute should be evaluated in future studies. Seasonal variation in airborne fungal concentrations could be attributable to various factors such as geoclimatic ones. Tokyo is located within the Temperate zone. The average temperatures in Tokyo in a recent year were 4.7 C in January, 17.0 C in April, 28.3 C in July, and 19.1 C in October. The monthly precipitation amounts were 48.5 mm in January, 109 mm in April, 107 mm in August, and 61.5 mm in October. Our results found higher airborne fungal concentrations in October than in the other months. Together with the temperature and precipitation data, it is plausible that the ‘indoor’ airborne fungal concentration could be related to both high temperature and low precipitation. The previous reports from other countries consistently revealed higher airborne fungal concentrations in summer or autumn than in winter [11e13]. In contrast, the study from Mexico did not show seasonal changes between rainy and dry seasons [10]. Therefore, geoclimatic factors and actual airborne fungal concentration data should be evaluated in each region or hospital when using these factors in risk assessments for IFD management. In the evaluation of the effect of airborne fungi on the incidence of IFD, not only the concentration but also the isolated species should be considered. In our study, the common isolated species were Cladosporium and Penicillium spp. Only a limited number of Aspergillus spp. were isolated, and notably only in July and October. In previous studies of indoor airborne fungal evaluations in hospitals, the common isolated species included Aspergillus spp. as well as Cladosporium and Penicillium spp [11e13]. In one study from Poland, the concentration of Aspergillus sp. was increased in October and November, which was in line with the increase in the concentration of total fungi [12]. These results indicated that
Please cite this article as: Mori T et al., Seasonal changes in indoor airborne fungal concentration in a hematology ward, J Infect Chemother, https://doi.org/10.1016/j.jiac.2019.10.020
4
T. Mori et al. / J Infect Chemother xxx (xxxx) xxx
seasonal variation in airborne fungal species could exist with regional differences, possibly affecting the incidence of IFD among the regions. There are several limitations in our study. One was the lack of epidemiological data on the patients who developed IFD during the study period in the hematology ward. Although not available for statistical analysis, an infection surveillance of Keio University Hospital in one year demonstrated that 60% of cases of pulmonary aspergillosis among adult patients with hematological disorders were diagnosed in peri-October period between September and early December (unpublished data). The result may have an association with the results of our present study showing the highest indoor airborne fungal concentrations in October. Another limitation was the limited number of evaluations, which were not performed every month but rather four times during the course of a year. Also, the results were all obtained in a single year rather than over multiple years. The other limitation was that not all the fungal species were identified. In conclusion, the seasonal variation of indoor airborne fungal concentration was demonstrated in a hospital in Japan. Aspergillus sp. was detected only in June and October. Future studies should elucidate the role of the seasonal variation of airborne fungal concentration in the incidence of IFD throughout a year. Declaration of Competing Interest Takehiko Mori received research funding from MSD, Novartis Pharma, LSI Medience, Medical & Biological Laboratories, and Asahi Kasei Corporation, and personal fees from Pfizer Inc., MSD, Janssen Pharma, Sumitomo Dainippon Pharma, Novartis Pharma, Kyowa Kirin, Chugai Pharmaceutical, Shionogi & Co., Japan Blood Products Organization, Takeda Pharmaceutical, Ono Pharmaceutical, Shire, Eisai, and Astellas Pharma; Taku Kikuchi received personal fees from Janssen Pharma; Jun Kato received personal fees from Pfizer Inc., Janssen Pharma, and Astellas Pharma; Naoki Hasegawa received personal fees and research funding from Pfizer Inc., MSD, Daiichi Sankyo Co., Ltd, Taisho Pharmaceutical Co., Ltd.,Eisai Co., Ltd, Sumitomo Dainippon Pharma, and Astellas Pharma, and grant from Insmed Incorporated; Shinichiro Okamoto received research funding from Sumitomo Dainippon Pharma, Pfizer, Teijin pharma, Novartis Pharma, Bristol-Myers Squibb, Mochida Pharmaceutical, JCR Pharmaceuticals, Toyama Chemical, Takeda Pharmaceutical, Daiichi Sankyo, Shionogi & Co., Sanofi, Kyowa Kirin, Ono Pharmaceutical, Otsuka Pharmaceutical, Eisai, Asahi Kasei Corporation, and Japan Blood Products Organization, and personal fees from Pfizer Inc., Janssen Pharma, and Astellas Pharma.
Acknowledgements The authors would like to thank Ms. Takako Kasai for kindly providing the surveillance data of pulmonary aspergillosis at Keio University Hospital. This work was partly supported by the research funding from Shionogi & Co., Ltd., Teijin Pharma, and Japan Blood Products Organization. References [1] Maertens JA, Girmenia C, Bruggemann RJ, Duarte RF, Kibbler CC, Ljungman P, et al. European guidelines for primary antifungal prophylaxis in adult haematology patients: summary of the updated recommendations from the European Conference on Infections in Leukaemia. J Antimicrob Chemother 2018;73:3221e30. [2] Robenshtok E, Gafter-Gvili A, Goldberg E, Weinberger M, Yeshurun M, Leibovici L, et al. Antifungal prophylaxis in cancer patients after chemotherapy or hematopoietic stem-cell transplantation: systematic review and metaanalysis. J Clin Oncol 2007;25:5471e89. [3] Glasmacher A, Prentice A, Gorschluter M, Engelhart S, Hahn C, Djulbegovic B, et al. Itraconazole prevents invasive fungal infections in neutropenic patients treated for hematologic malignancies: evidence from a meta-analysis of 3,597 patients. J Clin Oncol 2003;21:4615e26. [4] Cornely OA, Maertens J, Winston DJ, Perfect J, Ullmann AJ, Walsh TJ, et al. Posaconazole vs. fluconazole or itraconazole prophylaxis in patients with neutropenia. N Engl J Med 2007;356:348e59. [5] Wingard JR, Carter SL, Walsh TJ, Kurtzberg J, Small TN, Baden LR, et al. Randomized, double-blind trial of fluconazole versus voriconazole for prevention of invasive fungal infection after allogeneic hematopoietic cell transplantation. Blood 2010;116:5111e8. [6] Yokoe D, Casper C, Dubberke E, Lee G, Munoz P, Palmore T, et al. Infection prevention and control in health-care facilities in which hematopoietic cell transplant recipients are treated. Bone Marrow Transplant 2009;44:495e507. [7] Tomblyn M, Chiller T, Einsele H, Gress R, Sepkowitz K, Storek J, et al. Guidelines for preventing infectious complications among hematopoietic cell transplantation recipients: a global perspective. Biol Blood Marrow Transplant 2009;15:1143e238. [8] Wald A, Leisenring W, van Burik JA, Bowden RA. Epidemiology of Aspergillus infections in a large cohort of patients undergoing bone marrow transplantation. J Infect Dis 1997;175:1459e66. [9] Panackal AA, Li H, Kontoyiannis DP, Mori M, Perego CA, Boeckh M, et al. Geoclimatic influences on invasive aspergillosis after hematopoietic stem cell transplantation. Clin Infect Dis 2010;50:1588e97. [10] Martinez-Herrera EO, Frias De-Leon MG, Duarte-Escalante E, CalderonEzquerro Mdel C, Jimenez-Martinez Mdel C, Acosta-Altamirano G, et al. Fungal diversity and Aspergillus species in hospital environments. Ann Agric Environ Med 2016;23:264e9. [11] Sautour M, Sixt N, Dalle F, L'Ollivier C, Fourquenet V, Calinon C, et al. Profiles and seasonal distribution of airborne fungi in indoor and outdoor environments at a French hospital. Sci Total Environ 2009;407:3766e71. [12] Augustowska M, Dutkiewicz J. Variability of airborne microflora in a hospital ward within a period of one year. Ann Agric Environ Med 2006;13:99e106. [13] Verde SC, Almeida SM, Matos J, Guerreiro D, Meneses M, Faria T, et al. Microbiological assessment of indoor air quality at different hospital sites. Res Microbiol 2015;166:557e63. [14] Kanda Y. Investigation of the freely available easy-to-use software 'EZR' for medical statistics. Bone Marrow Transplant 2013;48:452e8.
Please cite this article as: Mori T et al., Seasonal changes in indoor airborne fungal concentration in a hematology ward, J Infect Chemother, https://doi.org/10.1016/j.jiac.2019.10.020
Contents lists available at ScienceDirect
Journal of Infection and Chemotherapy journal homepage: http://www.elsevier.com/locate/jic
Original Article
Seasonal changes in indoor airborne fungal concentration in a hematology ward* Takehiko Mori a, b, *, Taku Kikuchi a, Jun Kato a, Yuya Koda a, Masatoshi Sakurai a, Osamu Kikumi c, Rika Inose d, Mitsuru Murata e, Naoki Hasegawa b, f, Hitomi Nakayama a, Rie Yamazaki a, Shinichiro Okamoto a a
Division of Hematology, Department of Medicine, Keio University School of Medicine, Tokyo, Japan Center for Infectious Disease and Infection Control, Keio University Hospital, Tokyo, Japan Research & Development Division, Midori Anzen Co. Ltd., Tokyo, Japan d Office of Clinical Laboratory Technology, Keio University Hospital, Tokyo, Japan e Department of Laboratory Medicine, Keio University School of Medicine, Tokyo, Japan f Department for Infectious Diseases, Keio University School of Medicine, Tokyo, Japan b c
a r t i c l e i n f o
a b s t r a c t
Article history: Received 5 September 2019 Received in revised form 17 October 2019 Accepted 29 October 2019 Available online xxx
Invasive fungal disease (IFD) is an important infectious complication of hematological disorders, especially in hematopoietic stem cell transplantation recipients. Evidences suggest seasonal and/or geographical variations in the airborne fungal counts and a relationship between those counts and the incidence of IFD. We evaluated the concentrations of indoor airborne fungi quantitated over the course of one year in a hematology ward in Japan. In January, April, July, and October, fixed volumes of air samples were obtained by an air sampler in a hematology ward not equipped with a high-efficiency particulate air filter and incubated in fugal cultures. Samples were also obtained from a protective environment in the same ward and were evaluated. The number of fungal colonies per 50 L of sampled air was highest in October (median 2.25 (range, 0.2e7.0)), which was significantly higher than those in the other three months (0.1 (range, 0e1.0) in January; 0 (0-0) in April; 0.55 (0e2.5) in July; P < 0.01)). Commonly identified pathogens included Penicillium and Cladosrporium species, but Aspergillus species was detected only in July and October samples. These results suggest a seasonal variation in indoor airborne fungal concentrations in Japan, which could affect the epidemiology of IFD. © 2019 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.
Keywords: Fungus Airborne fungus Hematology ward Seasonal change Invasive fungal disease
1. Introduction Patients with hematological malignancies, especially recipients of hematopoietic stem cell transplantation (HSCT), are at high risk of developing invasive fungal disease (IFD). Against Candida species (spp.), the efficacy of prophylaxes using fluconazole and other agents has been established and widely used for these high-risk patients [1,2]. In contrast, although studies have demonstrated the efficacy of anti-mold agents such as itraconazole, voriconazole,
* All authors meet the ICMJE authorship criteria. * Corresponding author. Division of Hematology, Department of Medicine, Keio University School of Medicine 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan. E-mail address: [email protected] (T. Mori).
and posaconazole in preventing aspergillosis [1,3e5], invasive aspergillosis remains a critical life-threatening complication in these high-risk patients. A protective environment equipped with a high-efficiency particulate air (HEPA) filter has been recognized as a highly useful asset for preventing exposure to Aspergillus spp. and its use is recommended especially after allogeneic HSCT [6e8]. Geoclimatic effects on environmental airborne fungi counts and their relationship to the incidence of invasive aspergillosis after HSCT were evaluated in the United States [9] In that study, seasonal variations in outdoor airborne fungal concentrations were observed, and were found to be significantly associated with the incidence of aspergillosis. With regard to the evaluation of the indoor airborne fungal load in a hospital, a limited number of studies from different countries have shown different results, which also suggested a geoclimatic effect [10e13]. In the present study, seasonal changes in the indoor airborne fungal concentration in the
https://doi.org/10.1016/j.jiac.2019.10.020 1341-321X/© 2019 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.
Please cite this article as: Mori T et al., Seasonal changes in indoor airborne fungal concentration in a hematology ward, J Infect Chemother, https://doi.org/10.1016/j.jiac.2019.10.020
2
T. Mori et al. / J Infect Chemother xxx (xxxx) xxx
environment of a hematology ward of a university hospital in Tokyo, Japan were evaluated.
samples from the protective environment showed no significant differences among the 4 months (P ¼ 0.658, Table 1).
2. Materials and methods
3.2. Airborne fungal concentrations
2.1. Air sampling
The indoor airborne fungi were quantitatively evaluated by counting the colonies in each sample. In the nonprotective environment, the concentration of airborne fungi per 50 L sample was significantly higher in October than in the other 3 months (P < 0.00001, Fig. 1). In the protective environment, there were no significant differences in the fungal concentrations among the 4 months (P ¼ 0.522, Fig. 1). The concentrations were lower in the protective environment than in the nonprotective environment at each sampling month. The differences were significant in July and October (P < 0.001 and < 0.000001, respectively) but the significance was borderline in January and April (P ¼ 0.086 and 0.094, respectively).
All air samplings were performed at the hematology ward of Keio University Hospital (Tokyo, Japan). The ward consisted of 41 beds, including 21 beds in a high-efficiency particulate air (HEPA)filtered protective environment and 20 in a nonprotective environment. In January, April, July, and October, air samples were obtained by using a commercially available air sampler (BIOSAMP MBS-1000, Midori Anzen Co., Ltd., Tokyo, Japan) at two fixed places in the non-HEPA-filtered environment (nonprotective environment) and at two fixed places in the HEPA-filtered protective environment. The volumes of obtained air for each sampling were 50, 100, and 250 L. Sampling was performed in triplicate; that is, 9 samples were obtained at each place and at each time.
3.3. Identification of fungal species
2.2. Fungal cultures
The fungal species identified are shown in Table 2. The common isolates from the nonprotective environments were Cladosporium sp. and Penicillium sp., which were followed by Rhodotorula sp. and
Samples were collected on potato dextrose agar plates and incubated at 25 C for 4e5 days followed by 2 days at room temperature. After incubation, the identified colonies were counted. Based on the air sample volume for each plate, the numbers of colonies per 50 L air volume were compared. Each colony was examined to identify the species morphologically and micromorphologically by using Miura LCA medium and/or CHROMAgar medium as appropriate.
Number of colonies/50 L of air
7
2.3. Statistical analysis Differences in the number of positive cultures and in the number of fungal colonies were compared by using Fisher's exact test and the Friedman test, respectively. Values of P < 0.05 were considered statistically significant. All statistical analyses were performed by using EZR, a graphical user interface for R [14].
6 5 *
4 3 2 1
3. Results
**
0 3.1. Airborne fungal evaluation on sample basis
Jan
Apr
Jul
Jan
Oct
Nonprotective environment
Table 1 shows the numbers of culture samples yielding any fungal colonies from the 18 samples obtained per sampling time. In the nonprotective environment, significantly more of the October samples were positive for fungal colonies compared to the other 3 months (P < 0.01). Fewer of the samples from the protective environment were positive for fungi compared with the samples from the nonprotective environment. In contrast to the samples from the nonprotective environment, the number of positive
Apr
Jul
** Oct
Protective environment
Fig. 1. Airborne fungal concentrations in nonprotective and protective environments. In the nonprotective environment, the airborne fungal concentration was significantly higher in October than in the other 3 months (*P < 0.00001). There was no significant difference among the 4 months in the protective environment (P ¼ 0.522). The concentrations were lower in the protective environment than in the nonprotective environment at each sampling month. The differences were significant in July and October (**P < 0.001 and < 0.000001, respectively) but with borderline significance in January and April (P ¼ 0.086 and 0.094, respectively).
Table 1 Number of samples positive for fungi. January
April a
Nonprotective environment Positve Negative Protective environment Positve Negative a b
July a
October a
P value a
(N ¼ 18 )
(N ¼ 18 )
(N ¼ 18 )
(N ¼ 18 )
12 6
8 10
11 7
18 0
<0.01
3b 15
3 15
1b 17
4b 14
0.658
Nine culture samples obtained from at two places were evaluated. Significantly decreased as compared with nonprotective environment (P < 0.01, <0.001, <0.00001, respectively).
Please cite this article as: Mori T et al., Seasonal changes in indoor airborne fungal concentration in a hematology ward, J Infect Chemother, https://doi.org/10.1016/j.jiac.2019.10.020
T. Mori et al. / J Infect Chemother xxx (xxxx) xxx
3
Table 2 Identified species of airborne fungus in nonprotective and protective environments. January
April
July
October
Species
No. of colonies
Species
No. of colonies
Species
No. of colonies
Species
No. of colonies
Nonprotective environment
C. cladosporioides Penicillium sp. C. sphaerospermum Cladosporium sp. Rhodotorula sp. Phoma sp.
3 2 1 1 1 1
C. cladosporioides C. albidus Penicillium sp. R. mucilaginosa Cryptocossus sp. Unidentified (yeast)
4 2 1 1 1 1
Penicillium sp. C. sphaerospermum Cryptocossus sp. Rhodotorula sp. Arthrinium sp. Trametes sp. Cladosporium sp. Monochaetia sp. Rhinocladiellas sp A. sydowii Aspergillus sp. Unidentified (mold) Unidentified (yeast)
18 4 4 2 2 2 1 1 1 1 1 6 1
Protective environment
Cryptococcus sp. R. mucilaginosa C. sphaerospermum Unidentified (mold)
5 1 1 1
C. cladosporioides C. albidus Alternaria sp.
1 1 1
Penicillium sp.
1
Penicillium sp. C. sphaerospermum C. cladosporioides Cladosporium sp. Paecilomyces sp. C. albidus Aspergillus sp. Rhodotorula sp. A. fumigatus Aspergillus niger R. mucilaginosa Wallemia sebi Unidentified (mold) Unidentified (yeast) Penicillium sp. R. mucilaginosa
61 13 8 6 5 3 3 2 1 1 1 1 11 2 2 1
The species were identified morphologically and micromorphologically. Unidentified’ does not account for single species. C. cladosporioides, Cladosporium cladosporioides; C. sphaerospermum, Cladosporium sphaerospermum; R. mucilaginosa, Rhodotorula mucilaginosa; C. albidus, Cryptocossus albidus; A. fumigatus, Aspergillus fumigatus; A. sydowii, Aspergillus sydowii.
Cryptocossus sp. During the study period, there were no cases of IFD due to commonly isolated pathogens such as Cladosporium and Penicillium spp. Aspergillus spp. were isolated only in July and October. In the protective environment, common isolates were Cryptocossus, Cladosporium, and Penicillium spp. Aspergillus sp. was not isolated from any sampling month in the protective environment. 4. Discussion In this study, the seasonal variation of indoor airborne fungal concentrations was demonstrated in a hematology ward, with the highest concentrations observed in October. Although an epidemiological evaluation was not performed, this seasonal variation could affect the environmental risk of airborne fungal infection in an in-patient setting. Aspergillus spp. were detected only in June and October. The protective environment successfully and significantly decreased the fungal concentrations throughout the year, eliminating the seasonal variability in the concentration. Airborne molds cause life-threatening IFD in immunocompromised patients, especially those with hematological malignancies and recipients of HSCT. The inhalation of airborne fungal spores is the most likely cause of pulmonary IFD. Therefore, a protective environment, which is the most effective way to remove airborne fungal spores from the environment, has been recommended and widely used for the prophylaxis of airborne IFD [6e8]. The association between seasonal changes in environmental airborne fungi and the incidence of IFD has been demonstrated [9]. In that study, conducted in Seattle in the United States, the ‘outdoor’ environmental fungal spore concentration was significantly increased in the summer, which was significantly related to the incidence of invasive aspergillosis among HSCT recipients in that city. That was the first study to show an epidemiological effect of seasonal changes in outdoor airborne fungal concentrations on the incidence of IFD. However, it is plausible that the ‘indoor’ airborne fungal concentration would have a greater effect than the outdoor concentration on the incidence of IFD in an in-patient setting, since most high-risk patients are managed as in-patients. The seasonal variations of indoor airborne fungal concentrations in hospitals have been evaluated in several countries, including France, Mexico,
Poland, and Portugal [10e13]. Except for the study conducted in Mexico [10], these studies consistently demonstrated seasonal changes in airborne fungal concentrations in hospitals. Consistent with the results of the studies, our results showed a seasonal variation in the ‘indoor’ airborne fungal concentration in a hospital in Japan. Such seasonal variation could affect the incidence of institutional and/or regional IFD, and it should be incorporated into IFD risk assessments in the management of immunocompromised patients. The relationship between indoor airborne fungal concentration and the incidence of IFD at each institute should be evaluated in future studies. Seasonal variation in airborne fungal concentrations could be attributable to various factors such as geoclimatic ones. Tokyo is located within the Temperate zone. The average temperatures in Tokyo in a recent year were 4.7 C in January, 17.0 C in April, 28.3 C in July, and 19.1 C in October. The monthly precipitation amounts were 48.5 mm in January, 109 mm in April, 107 mm in August, and 61.5 mm in October. Our results found higher airborne fungal concentrations in October than in the other months. Together with the temperature and precipitation data, it is plausible that the ‘indoor’ airborne fungal concentration could be related to both high temperature and low precipitation. The previous reports from other countries consistently revealed higher airborne fungal concentrations in summer or autumn than in winter [11e13]. In contrast, the study from Mexico did not show seasonal changes between rainy and dry seasons [10]. Therefore, geoclimatic factors and actual airborne fungal concentration data should be evaluated in each region or hospital when using these factors in risk assessments for IFD management. In the evaluation of the effect of airborne fungi on the incidence of IFD, not only the concentration but also the isolated species should be considered. In our study, the common isolated species were Cladosporium and Penicillium spp. Only a limited number of Aspergillus spp. were isolated, and notably only in July and October. In previous studies of indoor airborne fungal evaluations in hospitals, the common isolated species included Aspergillus spp. as well as Cladosporium and Penicillium spp [11e13]. In one study from Poland, the concentration of Aspergillus sp. was increased in October and November, which was in line with the increase in the concentration of total fungi [12]. These results indicated that
Please cite this article as: Mori T et al., Seasonal changes in indoor airborne fungal concentration in a hematology ward, J Infect Chemother, https://doi.org/10.1016/j.jiac.2019.10.020
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seasonal variation in airborne fungal species could exist with regional differences, possibly affecting the incidence of IFD among the regions. There are several limitations in our study. One was the lack of epidemiological data on the patients who developed IFD during the study period in the hematology ward. Although not available for statistical analysis, an infection surveillance of Keio University Hospital in one year demonstrated that 60% of cases of pulmonary aspergillosis among adult patients with hematological disorders were diagnosed in peri-October period between September and early December (unpublished data). The result may have an association with the results of our present study showing the highest indoor airborne fungal concentrations in October. Another limitation was the limited number of evaluations, which were not performed every month but rather four times during the course of a year. Also, the results were all obtained in a single year rather than over multiple years. The other limitation was that not all the fungal species were identified. In conclusion, the seasonal variation of indoor airborne fungal concentration was demonstrated in a hospital in Japan. Aspergillus sp. was detected only in June and October. Future studies should elucidate the role of the seasonal variation of airborne fungal concentration in the incidence of IFD throughout a year. Declaration of Competing Interest Takehiko Mori received research funding from MSD, Novartis Pharma, LSI Medience, Medical & Biological Laboratories, and Asahi Kasei Corporation, and personal fees from Pfizer Inc., MSD, Janssen Pharma, Sumitomo Dainippon Pharma, Novartis Pharma, Kyowa Kirin, Chugai Pharmaceutical, Shionogi & Co., Japan Blood Products Organization, Takeda Pharmaceutical, Ono Pharmaceutical, Shire, Eisai, and Astellas Pharma; Taku Kikuchi received personal fees from Janssen Pharma; Jun Kato received personal fees from Pfizer Inc., Janssen Pharma, and Astellas Pharma; Naoki Hasegawa received personal fees and research funding from Pfizer Inc., MSD, Daiichi Sankyo Co., Ltd, Taisho Pharmaceutical Co., Ltd.,Eisai Co., Ltd, Sumitomo Dainippon Pharma, and Astellas Pharma, and grant from Insmed Incorporated; Shinichiro Okamoto received research funding from Sumitomo Dainippon Pharma, Pfizer, Teijin pharma, Novartis Pharma, Bristol-Myers Squibb, Mochida Pharmaceutical, JCR Pharmaceuticals, Toyama Chemical, Takeda Pharmaceutical, Daiichi Sankyo, Shionogi & Co., Sanofi, Kyowa Kirin, Ono Pharmaceutical, Otsuka Pharmaceutical, Eisai, Asahi Kasei Corporation, and Japan Blood Products Organization, and personal fees from Pfizer Inc., Janssen Pharma, and Astellas Pharma.
Acknowledgements The authors would like to thank Ms. Takako Kasai for kindly providing the surveillance data of pulmonary aspergillosis at Keio University Hospital. This work was partly supported by the research funding from Shionogi & Co., Ltd., Teijin Pharma, and Japan Blood Products Organization. References [1] Maertens JA, Girmenia C, Bruggemann RJ, Duarte RF, Kibbler CC, Ljungman P, et al. European guidelines for primary antifungal prophylaxis in adult haematology patients: summary of the updated recommendations from the European Conference on Infections in Leukaemia. J Antimicrob Chemother 2018;73:3221e30. [2] Robenshtok E, Gafter-Gvili A, Goldberg E, Weinberger M, Yeshurun M, Leibovici L, et al. Antifungal prophylaxis in cancer patients after chemotherapy or hematopoietic stem-cell transplantation: systematic review and metaanalysis. J Clin Oncol 2007;25:5471e89. [3] Glasmacher A, Prentice A, Gorschluter M, Engelhart S, Hahn C, Djulbegovic B, et al. Itraconazole prevents invasive fungal infections in neutropenic patients treated for hematologic malignancies: evidence from a meta-analysis of 3,597 patients. J Clin Oncol 2003;21:4615e26. [4] Cornely OA, Maertens J, Winston DJ, Perfect J, Ullmann AJ, Walsh TJ, et al. Posaconazole vs. fluconazole or itraconazole prophylaxis in patients with neutropenia. N Engl J Med 2007;356:348e59. [5] Wingard JR, Carter SL, Walsh TJ, Kurtzberg J, Small TN, Baden LR, et al. Randomized, double-blind trial of fluconazole versus voriconazole for prevention of invasive fungal infection after allogeneic hematopoietic cell transplantation. Blood 2010;116:5111e8. [6] Yokoe D, Casper C, Dubberke E, Lee G, Munoz P, Palmore T, et al. Infection prevention and control in health-care facilities in which hematopoietic cell transplant recipients are treated. Bone Marrow Transplant 2009;44:495e507. [7] Tomblyn M, Chiller T, Einsele H, Gress R, Sepkowitz K, Storek J, et al. Guidelines for preventing infectious complications among hematopoietic cell transplantation recipients: a global perspective. Biol Blood Marrow Transplant 2009;15:1143e238. [8] Wald A, Leisenring W, van Burik JA, Bowden RA. Epidemiology of Aspergillus infections in a large cohort of patients undergoing bone marrow transplantation. J Infect Dis 1997;175:1459e66. [9] Panackal AA, Li H, Kontoyiannis DP, Mori M, Perego CA, Boeckh M, et al. Geoclimatic influences on invasive aspergillosis after hematopoietic stem cell transplantation. Clin Infect Dis 2010;50:1588e97. [10] Martinez-Herrera EO, Frias De-Leon MG, Duarte-Escalante E, CalderonEzquerro Mdel C, Jimenez-Martinez Mdel C, Acosta-Altamirano G, et al. Fungal diversity and Aspergillus species in hospital environments. Ann Agric Environ Med 2016;23:264e9. [11] Sautour M, Sixt N, Dalle F, L'Ollivier C, Fourquenet V, Calinon C, et al. Profiles and seasonal distribution of airborne fungi in indoor and outdoor environments at a French hospital. Sci Total Environ 2009;407:3766e71. [12] Augustowska M, Dutkiewicz J. Variability of airborne microflora in a hospital ward within a period of one year. Ann Agric Environ Med 2006;13:99e106. [13] Verde SC, Almeida SM, Matos J, Guerreiro D, Meneses M, Faria T, et al. Microbiological assessment of indoor air quality at different hospital sites. Res Microbiol 2015;166:557e63. [14] Kanda Y. Investigation of the freely available easy-to-use software 'EZR' for medical statistics. Bone Marrow Transplant 2013;48:452e8.
Please cite this article as: Mori T et al., Seasonal changes in indoor airborne fungal concentration in a hematology ward, J Infect Chemother, https://doi.org/10.1016/j.jiac.2019.10.020