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Dladla M, Gyzenhout M, Marias G, Ghosh S. Azole resistance in Aspergillus fumigatus- comprehensive review. Arch Microbiol 2024; 206:305. [PMID: 38878211 DOI: 10.1007/s00203-024-04026-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2024] [Revised: 05/28/2024] [Accepted: 05/31/2024] [Indexed: 06/23/2024]
Abstract
Aspergillus fumigatus is a ubiquitous filamentous fungus commonly found in the environment. It is also an opportunistic human pathogen known to cause a range of respiratory infections, such as invasive aspergillosis, particularly in immunocompromised individuals. Azole antifungal agents are widely used for the treatment and prophylaxis of Aspergillus infections due to their efficacy and tolerability. However, the emergence of azole resistance in A. fumigatus has become a major concern in recent years due to their association with increased treatment failures and mortality rates. The development of azole resistance in A. fumigatus can occur through both acquired and intrinsic mechanisms. Acquired resistance typically arises from mutations in the target enzyme, lanosterol 14-α-demethylase (Cyp51A), reduces the affinity of azole antifungal agents for the enzyme, rendering them less effective, while intrinsic resistance refers to a natural resistance of certain A. fumigatus isolates to azole antifungals due to inherent genetic characteristics. The current review aims to provide a comprehensive overview of azole antifungal resistance in A. fumigatus, discusses underlying resistance mechanisms, including alterations in the target enzyme, Cyp51A, and the involvement of efflux pumps in drug efflux. Impact of azole fungicide uses in the environment and the spread of resistant strains is also explored.
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Affiliation(s)
- Mthokozisi Dladla
- Department of Genetics, Faculty of Natural and Agricultural Sciences, University of the Free State, Bloemfontein, 9301, South Africa
| | - Marieka Gyzenhout
- Department of Genetics, Faculty of Natural and Agricultural Sciences, University of the Free State, Bloemfontein, 9301, South Africa.
| | - Gert Marias
- Department of Plant Sciences, Division of Plant Pathology, Faculty of Natural and Agricultural Sciences, University of the Free State, Bloemfontein, South Africa
| | - Soumya Ghosh
- Department of Genetics, Faculty of Natural and Agricultural Sciences, University of the Free State, Bloemfontein, 9301, South Africa.
- Natural and Medical Sciences Research Center, University of Nizwa, Nizwa 616, Birkat Al Mawz, Oman.
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2
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Zhu G, Chen S, Zhang Y, Lu L. Mitochondrial Membrane-Associated Protein Mba1 Confers Antifungal Resistance by Affecting the Production of Reactive Oxygen Species in Aspergillus fumigatus. Antimicrob Agents Chemother 2023; 67:e0022523. [PMID: 37428039 PMCID: PMC10433838 DOI: 10.1128/aac.00225-23] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2023] [Accepted: 06/08/2023] [Indexed: 07/11/2023] Open
Abstract
Azole resistance in the human fungal pathogen Aspergillus fumigatus is becoming a major threat to global health. To date, mutations in the azole target-encoding cyp51A gene have been implicated in conferring azole resistance, but a steady increase in the number of A. fumigatus isolates with azole resistance resulting from non-cyp51A mutations has been recognized. Previous studies have revealed that some isolates with non-cyp51A mutation-induced azole resistance are related to mitochondrial dysfunction. However, knowledge of the molecular mechanism underlying the involvement of non-cyp51A mutations is limited. In this study, using next-generation sequencing, we found that nine independent azole-resistant isolates without cyp51A mutations had normal mitochondrial membrane potential. Among these isolates, a mutation in a mitochondrial ribosome-binding protein, Mba1, conferred multidrug resistance to azoles, terbinafine, and amphotericin B but not caspofungin. Molecular characterization verified that the TIM44 domain of Mba1 was crucial for drug resistance and that the N terminus of Mba1 played a major role in growth. Deletion of mba1 had no effect on Cyp51A expression but decreased the fungal cellular reactive oxygen species (ROS) content, which contributed to mba1-mediated drug resistance. The findings in this study suggest that some non-cyp51A proteins drive drug resistance mechanisms that result from reduced ROS production induced by antifungals.
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Affiliation(s)
- Guoxing Zhu
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology, College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Shu Chen
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology, College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Yuanwei Zhang
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology, College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Ling Lu
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology, College of Life Sciences, Nanjing Normal University, Nanjing, China
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3
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Shangali A, Kamori D, Massawe W, Masoud S, Kibwana U, Mwingwa AG, Manisha A, Mwandigha AM, Mirambo MM, Mshana SE, Manyahi J, Majigo M. Aetiology of ear infection and antimicrobial susceptibility pattern among patients attending otorhinolaryngology clinic at a tertiary hospital in Dar es Salaam, Tanzania: a hospital-based cross-sectional study. BMJ Open 2023; 13:e068359. [PMID: 37012005 PMCID: PMC10083798 DOI: 10.1136/bmjopen-2022-068359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 04/04/2023] Open
Abstract
OBJECTIVES To determine the aetiological pathogens causing ear infections and their antimicrobial susceptibility patterns among patients with ear complaints at a tertiary hospital in Dar es Salaam. DESIGN Hospital-based cross-sectional study. SETTINGS Otorhinolaryngology clinic at Muhimbili National Hospital, Dar es Salaam, Tanzania. PARTICIPANTS Patients presenting with signs and symptoms of ear infection. MAIN OUTCOME MEASURE Bacteria and fungi isolated from ear swab specimens of patients presenting with signs and symptoms of ear infection; and antimicrobial susceptibility patterns of isolated bacteria. RESULTS Two hundred and fifty-five participants were enrolled, with a median age of 31 years and an IQR of 15-49. Otitis externa was the predominant type of ear infection, accounting for 45.1%. We observed positive bacteria culture in 53.3% of study participants, in which 41% of isolates were obtained from patients with chronic suppurative otitis media. Moreover, Staphylococcus aureus (27.3%) and Pseudomonas aeruginosa (24.2%) were the most frequently isolated bacteria, while Candida spp, 12 (63.8%) and Aspergillus spp, 9 (36.2%) were the only isolated fungi. Furthermore, we report that 93% of isolated Enterobacterales were resistant to amoxicillin/clavulanic acid, and 73% were resistant to ceftazidime. In addition, we detected 34.4% extended-spectrum beta-lactamase-producing Enterobacterales (ESBL-PE) and 44.4% methicillin-resistance S. aureus (MRSA). We also found that 22% of the bacteria isolates were resistant to ciprofloxacin, a primary topical antibiotic used in managing ear infections. CONCLUSIONS The findings from this study reveal that the leading aetiological agent of ear infection is bacteria. Furthermore, our findings show a significant proportion of ESBL-PE and MRSA-causing ear infections. Hence, detecting multidrug-resistant bacteria is crucial to improving ear infection management.
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Affiliation(s)
- Aminiel Shangali
- Department of Microbiology and Immunology, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania, United Republic of
- Department of Microbiology and Immunology, Mwanza University, Mwanza, Tanzania, United Republic of
| | - Doreen Kamori
- Department of Microbiology and Immunology, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania, United Republic of
| | - Willybroad Massawe
- Department of Otorhinolaryngology, Muhimbili National Hospital, Dar es Salaam, Tanzania, United Republic of
| | - Salim Masoud
- Department of Microbiology and Immunology, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania, United Republic of
| | - Upendo Kibwana
- Department of Microbiology and Immunology, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania, United Republic of
| | - Anthony G Mwingwa
- Department of Microbiology and Immunology, Kilimanjaro Christian Medical Centre, Moshi, Tanzania, United Republic of
| | - Anselmo Manisha
- Department of Microbiology and Immunology, Mwanza University, Mwanza, Tanzania, United Republic of
| | - Ambele M Mwandigha
- Department of Microbiology and Immunology, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania, United Republic of
| | - Mariam M Mirambo
- Department of Microbiology and Immunology, Catholic University of Health and Allied Sciences, Mwanza, Tanzania, United Republic of
| | - Stephen E Mshana
- Department of Microbiology and Immunology, Catholic University of Health and Allied Sciences, Mwanza, Tanzania, United Republic of
| | - Joel Manyahi
- Department of Microbiology and Immunology, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania, United Republic of
| | - Mtebe Majigo
- Department of Microbiology and Immunology, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania, United Republic of
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Amona MF, Oladele RO, Resendiz-Sharpe A, Denning DW, Kosmidis C, Lagrou K, Zhong H, Han L. Triazole resistance in Aspergillus fumigatus isolates in Africa: a systematic review. Med Mycol 2022; 60:6652216. [PMID: 35906879 DOI: 10.1093/mmy/myac059] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Revised: 07/18/2022] [Accepted: 07/27/2022] [Indexed: 11/13/2022] Open
Abstract
Emergence of triazole resistance has been observed in Aspergillus fumigatus over the past decade including in Africa. This review summarizes the current published data on the epidemiology and reported mechanisms of triazole-resistant Aspergillus fumigatus (TRAF) in both environmental and clinical isolates from Africa. Searches on databases Medline, PubMed, HINARI, Science Direct, Scopus and Google Scholar on triazole resistance published between 2000 and 2021 from Africa were performed. Isolate source, antifungal susceptibility using internationally recognized methods, cyp51A mechanism of resistance and genotype were collected. Eleven published African studies were found that fitted the search criteria; these were subsequently analyzed. In total this constituted of 1686 environmental and 46 clinical samples. A TRAF prevalence of 17.1% (66/387) and 1,3% (5/387) was found in respectively environmental and clinical settings in African studies. Resistant to itraconazole, voriconazole, and posaconazole was documented. Most of the triazole-resistant isolates (30/71, 42.25%) were found to possess the TR34/L98H mutation in the cyp51A-gene; fewer with TR46/Y121F/T289A (n = 8), F46Y/M172V/E427K (n = 1), G54E (n = 13), and M172V (n = 1) mutations. African isolates with the TR34/L98H, TR46/Y121F/T289A and the G54E mutations were closely related and could be grouped in one of two clusters (cluster-B), whereas the cyp51A-M172V mutation clustered with most cyp51A- WT strains (cluster-A). A single case from Kenya shows that TR34/L98H from environmental and clinical isolates are closely related. Our findings highlight that triazole resistance in environmental and clinical A. fumigatus is a cause for concern in a number of African countries. There is need for epidemiological surveillance to determine the true burden of the problem in Africa.
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Affiliation(s)
- Modeste Fructueux Amona
- Faculty of Health Sciences, Marien Ngouabi University, Brazzaville, Republic of Congo.,Research Center and Study of Infectious and Tropical Pathologies, Oyo, Republic of Congo
| | - Rita Okeoghene Oladele
- Department of Medical Microbiology and Parasitology, College of Medicine, University of Lagos, Lagos, Nigeria.,Department of Medical Microbiology and Parasitology, Lagos University Teaching Hospital, Idi-Araba, Lagos, Nigeria
| | - Agustin Resendiz-Sharpe
- Department of Microbiology, Laboratory of Clinical Bacteriology and Mycology, Immunology and Transplantation, KU Leuven, Leuven, Belgium.,Department of Imaging and Pathology, Biomedical MRI, KU Leuven, Leuven, Belgium
| | - David W Denning
- Manchester Fungal Infection Group, the University of Manchester and Manchester Academic Health Science Centre, Manchester, United Kingdom
| | - Chris Kosmidis
- National Aspergillosis Centre, Manchester University Foundation Trust, UK, and Manchester Academic Health Science Centre, the University of Manchester, Manchester, UK
| | - Katrien Lagrou
- Department of Microbiology, Laboratory of Clinical Bacteriology and Mycology, Immunology and Transplantation, KU Leuven, Leuven, Belgium.,Department of Laboratory Medicine and National Reference Center for Mycosis, University Hospitals Leuven, Leuven, Belgium
| | - Hanying Zhong
- Department for Disinfection and Infection Control, Chinese PLA Center for Disease Control and Prevention, Beijing, China
| | - Li Han
- Department for Disinfection and Infection Control, Chinese PLA Center for Disease Control and Prevention, Beijing, China
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5
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Bader O. Phylogenetic Distribution of csp1 Types in Aspergillus fumigatus and Their Correlates to Azole Antifungal Drug Resistance. Microbiol Spectr 2021; 9:e0121421. [PMID: 34787484 PMCID: PMC8597649 DOI: 10.1128/spectrum.01214-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Accepted: 09/22/2021] [Indexed: 11/20/2022] Open
Abstract
In Aspergillus fumigatus, the repetitive region of the csp1 gene is one of the most frequently used loci for intraspecies typing of this human pathogenic mold. Using PCR amplification and Sanger sequencing of only a single marker, csp1 typing is readily available to most laboratories and highly reproducible. Here, I evaluate the usefulness of the csp1 marker for resistance detection and epidemiologic stratification among A. fumigatus isolates. After resolving nomenclature conflicts from published studies and adding novel csp1 types, the number of known types now adds up to 38. Their distribution mostly correlates with A. fumigatus population structure, and they are also meaningful for narrowly defined cases of azole resistance phenotypes. Isolates carrying the pandemic resistance allele TR34/L98H show signs of interclade crossing of strains with t02 or t04A, into the t11 clade. Furthermore, absolute differences in voriconazole MIC values between t02/t04B versus t11 TR34/L98H isolates indicate that the genetic background of resistance mutations may have a pivotal role in cross-resistance phenotypes and, thus, clinical outcome and environmental selection. Despite the general genetic similarity of isolates with identical csp1 types, outcrossing into other clades is also observed. The csp1 type alone, therefore, does not sufficiently discriminate genetic clades to be used as the sole marker in epidemiologic studies. IMPORTANCE Aspergillus fumigatus is a ubiquitously distributed saprophytic mold and a leading cause of invasive aspergillosis in human hosts. Pandemic azole-resistant strains have emerged on a global scale, which are thought to be propagated through use of azole-based fungicides in agriculture. To perform epidemiologic studies, genetic typing of large cohorts is key. Here, I evaluate the usefulness of the frequently used csp1 marker for resistance detection and epidemiologic stratification among A. fumigatus isolates. The phylogenetic distribution of csp1 types mostly correlates with A. fumigatus population structure and is also meaningful for narrowly defined cases of azole resistance phenotypes. Nevertheless, outcrossing of csp1 into other clades is also observed. The csp1 type alone, therefore, does not sufficiently discriminate genetic clades and should not be used as the sole marker in epidemiologic studies.
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Affiliation(s)
- Oliver Bader
- Institute for Medical Microbiology and Virology, University Medical Center Göttingen, Göttingen, Germany
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6
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Otu A, Osaigbovo I, Orefuwa E, Ebenso B, Ojumu T. Collaborative One Health approaches can mitigate increasing azole-resistant Aspergillus fumigatus in Africa. THE LANCET MICROBE 2021; 2:e490-e491. [DOI: 10.1016/s2666-5247(21)00218-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2021] [Accepted: 08/02/2021] [Indexed: 11/24/2022] Open
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7
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Arastehfar A, Carvalho A, Houbraken J, Lombardi L, Garcia-Rubio R, Jenks J, Rivero-Menendez O, Aljohani R, Jacobsen I, Berman J, Osherov N, Hedayati M, Ilkit M, Armstrong-James D, Gabaldón T, Meletiadis J, Kostrzewa M, Pan W, Lass-Flörl C, Perlin D, Hoenigl M. Aspergillus fumigatus and aspergillosis: From basics to clinics. Stud Mycol 2021; 100:100115. [PMID: 34035866 PMCID: PMC8131930 DOI: 10.1016/j.simyco.2021.100115] [Citation(s) in RCA: 114] [Impact Index Per Article: 38.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The airborne fungus Aspergillus fumigatus poses a serious health threat to humans by causing numerous invasive infections and a notable mortality in humans, especially in immunocompromised patients. Mould-active azoles are the frontline therapeutics employed to treat aspergillosis. The global emergence of azole-resistant A. fumigatus isolates in clinic and environment, however, notoriously limits the therapeutic options of mould-active antifungals and potentially can be attributed to a mortality rate reaching up to 100 %. Although specific mutations in CYP 51A are the main cause of azole resistance, there is a new wave of azole-resistant isolates with wild-type CYP 51A genotype challenging the efficacy of the current diagnostic tools. Therefore, applications of whole-genome sequencing are increasingly gaining popularity to overcome such challenges. Prominent echinocandin tolerance, as well as liver and kidney toxicity posed by amphotericin B, necessitate a continuous quest for novel antifungal drugs to combat emerging azole-resistant A. fumigatus isolates. Animal models and the tools used for genetic engineering require further refinement to facilitate a better understanding about the resistance mechanisms, virulence, and immune reactions orchestrated against A. fumigatus. This review paper comprehensively discusses the current clinical challenges caused by A. fumigatus and provides insights on how to address them.
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Affiliation(s)
- A. Arastehfar
- Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, NJ, 07110, USA
| | - A. Carvalho
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal
- ICVS/3B's - PT Government Associate Laboratory, Guimarães/Braga, Portugal
| | - J. Houbraken
- Westerdijk Fungal Biodiversity Institute, Utrecht, the Netherlands
| | - L. Lombardi
- UCD Conway Institute and School of Medicine, University College Dublin, Dublin 4, Ireland
| | - R. Garcia-Rubio
- Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, NJ, 07110, USA
| | - J.D. Jenks
- Department of Medicine, University of California San Diego, San Diego, CA, 92103, USA
- Clinical and Translational Fungal-Working Group, University of California San Diego, La Jolla, CA, 92093, USA
| | - O. Rivero-Menendez
- Medical Mycology Reference Laboratory, National Center for Microbiology, Instituto de Salud Carlos III, Madrid, 28222, Spain
| | - R. Aljohani
- Department of Infectious Diseases, Imperial College London, London, UK
| | - I.D. Jacobsen
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology—Hans Knöll Institute, Jena, Germany
- Institute for Microbiology, Friedrich Schiller University, Jena, Germany
| | - J. Berman
- Research Group Microbial Immunology, Leibniz Institute for Natural Product Research and Infection Biology—Hans Knöll Institute, Jena, Germany
| | - N. Osherov
- Department of Clinical Microbiology and Immunology, Sackler School of Medicine Ramat-Aviv, Tel-Aviv, 69978, Israel
| | - M.T. Hedayati
- Invasive Fungi Research Center/Department of Medical Mycology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran
| | - M. Ilkit
- Division of Mycology, Department of Microbiology, Faculty of Medicine, Çukurova University, 01330, Adana, Turkey
| | | | - T. Gabaldón
- Life Sciences Programme, Supercomputing Center (BSC-CNS), Jordi Girona, Barcelona, 08034, Spain
- Mechanisms of Disease Programme, Institute for Research in Biomedicine (IRB), Barcelona, Spain
- ICREA, Pg. Lluís Companys 23, Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA), Pg. Lluís Companys 23, 08010, Barcelona, Spain
| | - J. Meletiadis
- Clinical Microbiology Laboratory, Attikon University Hospital, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | | | - W. Pan
- Medical Mycology, Shanghai Changzheng Hospital, Second Military Medical University, Shanghai, 200003, China
| | - C. Lass-Flörl
- Institute of Hygiene and Medical Microbiology, Medical University of Innsbruck, Innsbruck, Austria
| | - D.S. Perlin
- Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, NJ, 07110, USA
| | - M. Hoenigl
- Department of Medicine, University of California San Diego, San Diego, CA, 92103, USA
- Section of Infectious Diseases and Tropical Medicine, Department of Internal Medicine, Medical University of Graz, 8036, Graz, Austria
- Division of Infectious Diseases and Global Public Health, Department of Medicine, University of California San Diego, San Diego, CA 92093, USA
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8
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Mshana SE, Sindato C, Matee MI, Mboera LEG. Antimicrobial Use and Resistance in Agriculture and Food Production Systems in Africa: A Systematic Review. Antibiotics (Basel) 2021; 10:976. [PMID: 34439026 PMCID: PMC8389036 DOI: 10.3390/antibiotics10080976] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 08/07/2021] [Accepted: 08/08/2021] [Indexed: 01/10/2023] Open
Abstract
In Africa, there is dearth of information on antimicrobial use (AMU) in agriculture and food production systems and its consequential resistance in pathogens that affect animal, human and environmental health. Data published between 1980 and 2021 on the magnitude of AMU and AMR in agriculture and food productions systems in Africa were reviewed. Data from 13-27 countries in Africa indicate that 3558-4279 tonnes of antimicrobials were used in animals from 2015 to 2019. Tetracyclines and polypeptides contributed the largest proportion of antimicrobials used. Cattle and poultry production account for the largest consumption of antimicrobials in Africa. Although limited studies have reported AMR in crops, fish and beekeeping, AMR from a variety of farm animals has been substantially documented in Africa. Some countries in Africa have developed policies/plans to address AMU and AMR in agriculture and food production systems; however, their enforcement is challenged by weak regulations. In conclusion, although there is limited information on the quantities of antimicrobials used in agriculture and food production system, the levels of AMR are high. There is a need to strengthen regulatory authorities with a capacity to monitor AMU in agriculture and food production systems in Africa.
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Affiliation(s)
- Stephen E. Mshana
- SACIDS Foundation for One Health, Sokoine University of Agriculture, Morogoro 65125, Tanzania; (S.E.M.); (C.S.); (M.I.M.)
- Catholic University of Health and Allied Sciences, P.O. Box 1424, Mwanza 33109, Tanzania
| | - Calvin Sindato
- SACIDS Foundation for One Health, Sokoine University of Agriculture, Morogoro 65125, Tanzania; (S.E.M.); (C.S.); (M.I.M.)
- National Institute for Medical Research, P.O. Box 482, Tabora 45026, Tanzania
| | - Mecky I. Matee
- SACIDS Foundation for One Health, Sokoine University of Agriculture, Morogoro 65125, Tanzania; (S.E.M.); (C.S.); (M.I.M.)
- Muhimbili University of Health and Allied Sciences, P.O. Box 65001, Dar es Salaam 11103, Tanzania
| | - Leonard E. G. Mboera
- SACIDS Foundation for One Health, Sokoine University of Agriculture, Morogoro 65125, Tanzania; (S.E.M.); (C.S.); (M.I.M.)
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9
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Kiakojuri K, Mahdavi Omran S, Roodgari S, Taghizadeh Armaki M, Hedayati MT, Shokohi T, Haghani I, Javidnia J, Kermani F, Badali H, Abastabar M. Molecular Identification and Antifungal Susceptibility of Yeasts and Molds Isolated from Patients with Otomycosis. Mycopathologia 2021; 186:245-257. [PMID: 33718990 DOI: 10.1007/s11046-021-00537-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2020] [Accepted: 02/17/2021] [Indexed: 11/29/2022]
Abstract
Fungal otitis externa, an infection of the external auditory canal caused by molds and yeasts, accounts for approximately 10-20% of ear canal infections accompanying high recurrence. The purpose of the current study was to assess the pattern of etiological agents of otomycosis and resistance profile as well as the rate of tympanic membrane perforation. A total of 1040 patients with symptoms of fungal otitis externa, in a period of two years, were investigated. The mycological tests revealed the presence of different fungi in 237 ears (22.8%). Fungal otitis was more related to filamentous fungi of the species Aspergillus flavus (54.43%), A. tubingensis (10.97%), and A. niger (8.86%), followed by yeasts, Candida orthopsilosis (7.59%), C. albicans (6.75%), and C. parapsilosis (5.06%). Tympanic membrane perforation rate was found to be 6.75% and was more common with otomycosis caused by A. flavus, A. tubingensis and C. albicans. In antifungal susceptibility tests, all tested drugs showed generally good activity against most isolates of molds and yeasts, while tolnaftate, clotrimazole, nystatin, and terbinafine had lowest effects. We found that among Aspergillus isolates, one A. niger isolate was resistant to voriconazole, and one A. flavus isolate was resistant to amphotericin B. Furthermore, among Candida species, three isolates of C. orthopsilosis showed high MIC values to fluconazole, two C. albicans isolates were considered fluconazole resistant and one isolate of C. parapsilosis was resistant to caspofungin and 3 isolates were resistant to fluconazole. Regarding the existence of the cases with perforated tympanic membrane and emerging species causing fungal otitis in the current report, the importance of the early physical examination, precise molecular identification, and the antifungal susceptibility evaluation is highlighted.
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Affiliation(s)
- Keyvan Kiakojuri
- Department of Ear, Nose, and Throat, Faculty of Medicine, Roohani Hospital, Babol University of Medical Sciences, Babol, Iran
| | - Saeid Mahdavi Omran
- Department of Medical Mycology, School of Medicine, Babol University of Medical Sciences, 47745-47176, Babol, Iran.
| | - Somayeh Roodgari
- Invasive Fungi Research Center, Communicable Diseases Institute, Mazandaran University of Medical Sciences, Sari, Iran.,Department of Medical Mycology, School of Medicine, Mazandaran University of Medical Sciences, 48175-1665, Sari, Iran.,Student Research Committee, Mazandaran University of Medical Sciences, Sari, Iran
| | - Mojtaba Taghizadeh Armaki
- Department of Medical Mycology, School of Medicine, Babol University of Medical Sciences, 47745-47176, Babol, Iran
| | - Mohammad Taghi Hedayati
- Invasive Fungi Research Center, Communicable Diseases Institute, Mazandaran University of Medical Sciences, Sari, Iran.,Department of Medical Mycology, School of Medicine, Mazandaran University of Medical Sciences, 48175-1665, Sari, Iran
| | - Tahereh Shokohi
- Invasive Fungi Research Center, Communicable Diseases Institute, Mazandaran University of Medical Sciences, Sari, Iran.,Department of Medical Mycology, School of Medicine, Mazandaran University of Medical Sciences, 48175-1665, Sari, Iran
| | - Iman Haghani
- Invasive Fungi Research Center, Communicable Diseases Institute, Mazandaran University of Medical Sciences, Sari, Iran.,Department of Medical Mycology, School of Medicine, Mazandaran University of Medical Sciences, 48175-1665, Sari, Iran
| | - Javad Javidnia
- Invasive Fungi Research Center, Communicable Diseases Institute, Mazandaran University of Medical Sciences, Sari, Iran.,Department of Medical Mycology, School of Medicine, Mazandaran University of Medical Sciences, 48175-1665, Sari, Iran.,Student Research Committee, Mazandaran University of Medical Sciences, Sari, Iran
| | - Firoozeh Kermani
- Invasive Fungi Research Center, Communicable Diseases Institute, Mazandaran University of Medical Sciences, Sari, Iran.,Department of Medical Mycology, School of Medicine, Mazandaran University of Medical Sciences, 48175-1665, Sari, Iran.,Student Research Committee, Mazandaran University of Medical Sciences, Sari, Iran
| | - Hamid Badali
- Invasive Fungi Research Center, Communicable Diseases Institute, Mazandaran University of Medical Sciences, Sari, Iran.,Department of Medical Mycology, School of Medicine, Mazandaran University of Medical Sciences, 48175-1665, Sari, Iran
| | - Mahdi Abastabar
- Invasive Fungi Research Center, Communicable Diseases Institute, Mazandaran University of Medical Sciences, Sari, Iran. .,Department of Medical Mycology, School of Medicine, Mazandaran University of Medical Sciences, 48175-1665, Sari, Iran.
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First Investigative Study of Azole-Resistant Aspergillus fumigatus in the Environment in Burkina Faso. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph18052250. [PMID: 33668719 PMCID: PMC7956412 DOI: 10.3390/ijerph18052250] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 02/17/2021] [Accepted: 02/18/2021] [Indexed: 01/10/2023]
Abstract
Azole-resistant Aspergillus fumigatus (ARAF) strains have been reported on all continents, however, limited data exist on these strains in Africa, while several factors, mainly environmental ones, suggest their presence on this continent. This study aimed to assess the environmental prevalence of ARAF strains in Burkina Faso, a country situated in the West African region where data on ARAF is non-existent. In total, 120 environmental samples (soil) were collected and analyzed. Samples were screened for resistance using three azole-containing agar plates; one without azole antifungal (growth control) and two supplemented with either itraconazole (4 mg/L) or voriconazole (2 mg/L). The EUCAST susceptibility testing method was used to confirm the azole-resistant phenotype of A. fumigatus sensu-stricto isolates. Mutations in the cyp51A gene were determined by sequencing. Of the 120 samples, 51 positive samples showed growth of A. fumigatus isolates on control medium. One ARAF (2%; 1/51) isolate was found amongst A. fumigatus positive samples and harbored the F46Y/M172V/E427K cyp51A mutations. No TR34/L98H or TR46/Y121F/T289A mutations were observed. Our study described the first A. fumigatus isolate resistant to an azole antifungal in Burkina Faso.
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Campbell CA, Osaigbovo II, Oladele RO. Triazole susceptibility of Aspergillus species: environmental survey in Lagos, Nigeria and review of the rest of Africa. Ther Adv Infect Dis 2021; 8:20499361211044330. [PMID: 34532039 PMCID: PMC8438939 DOI: 10.1177/20499361211044330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 08/18/2021] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND Triazole resistance is an emerging problem in the management of human aspergillosis globally and can arise in Aspergillus species which have been exposed to azole fungicides in the environment. We surveyed local government and council development areas in Lagos, Nigeria, to determine the distribution of Aspergillus species in the environment and their susceptibility to locally available triazole antifungal agents. We also reviewed the literature on the subject from the rest of Africa. METHODS A total of 168 soil samples from six locations in Lagos, Nigeria were processed and cultured on Saboraud dextrose agar impregnated with chloramphenicol to isolate Aspergillus species. Isolates were tested for susceptibility to itraconazole and voriconazole by microbroth dilution according to the European Committee on Antimicrobial Susceptibility Testing reference method. Relevant databases were searched to identify published work pertaining to triazole susceptibility of Aspergillus species in Africa. RESULTS A total of 117 Aspergillus species were isolated. Aspergillus niger was the most frequently isolated species (42.7%). Other species isolated were Aspergillus flavus, 37 (31.6%), Aspergillus terreus, 20 (17.1%), Aspergillus fumigatus, 5 (4.3%) and Aspergillus nidulans, 5 (4.3%). All isolates were susceptible to itraconazole and voriconazole. The literature review showed documented evidence of triazole-resistant Aspergillus species from East and West Africa. CONCLUSIONS We found no triazole resistance in environmental isolates of Aspergillus in Lagos, Nigeria. Nevertheless, regular surveillance in clinical and environmental isolates is necessary in the light of findings from other African studies.
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Affiliation(s)
- Cynthia Abosede Campbell
- Department of Medical Microbiology and Parasitology, College of Medicine, University of Lagos, Lagos, Nigeria
| | - Iriagbonse Iyabo Osaigbovo
- Department of Medical Microbiology, School of Medicine, College of Medical Sciences, University of Benin, Benin City, Nigeria
- Department of Medical Microbiology, University of Benin Teaching Hospital, Benin City, Nigeria
| | - Rita Okeoghene Oladele
- Department of Medical Microbiology and Parasitology, College of Medicine, University of Lagos, Lagos, Nigeria
- Department of Medical Microbiology and Parasitology, Lagos University Teaching Hospital, Idi-Araba, Lagos, Nigeria
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12
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Leach AJ, Homøe P, Chidziva C, Gunasekera H, Kong K, Bhutta MF, Jensen R, Tamir SO, Das SK, Morris P. Panel 6: Otitis media and associated hearing loss among disadvantaged populations and low to middle-income countries. Int J Pediatr Otorhinolaryngol 2020; 130 Suppl 1:109857. [PMID: 32057518 PMCID: PMC7259423 DOI: 10.1016/j.ijporl.2019.109857] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
OBJECTIVE: Summarise the published evidence on otitis media and associated hearing loss in low to middle-income countries (LMIC) and disadvantaged populations. DATA SOURCES: PubMed and other databases. REVIEW METHODS: Firstly, sensitive search strategy using ‘otitis media’, combined with specific key words for each topic of the review, from January 2015 to June 2019. Then, restriction to LMIC and disadvantaged populations. Topics covered included prevention, epidemiology, risk factors, microbiology, prognosis, diagnosis, and treatment. CONCLUSIONS: There was a high degree of methodological heterogeneity and high risk of bias. The majority of studies were school-based. In Africa, Asia and Oceania (e.g., Australian Aboriginal populations) the prevalence of OM was respectively 8% (range 3–16%), 14% (range 7–22%) and 50% (4–95%). Prevalence of any hearing loss in these regions was 12% (range 8–17%), 12% (range 3–24%), and 26% (range 25–28%) respectively. Risk factors in LMIC and disadvantaged populations included age, gender, exposure to smoke and pollution. Microbiology was reported for otitis media with effusion at time of surgery or ear discharge (acute otitis media with perforation or chronic suppurative otitis media). Specimen handling and processing in hospital laboratories was associated with low detection of S. pneumoniae and H. influenzae. Case series described complicated cases of OM due to M. tuberculosis, multidrug resistance and HIV. QOL studies identified discrimination of persons with OM and hearing loss. Diagnostic methods varied greatly, from naked eye to tympanometry. Treatment interventions were reported from four RCTs. Non-RCTs included evaluations of guidelines, surgery outcomes, access to ENTs. IMPLICATIONS FOR CLINICAL PRACTICE: Chronic suppurative otitis media, otitis media with effusion and conductive hearing loss are common in LMIC and disadvantaged populations. Paucity of research, poor regional representation, non-standardised methods and low-quality reporting preclude accurate assessment of disease burden in LMIC and disadvantaged populations. Awareness and adherence to reporting Guidelines should be promoted.
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Affiliation(s)
- Amanda Jane Leach
- Menzies School of Health Research, John Mathews Building 58, Royal Darwin Hospital Campus, Rocklands Dr, Tiwi, NT, 0810, Australia.
| | - Preben Homøe
- Køge University Hospital, Copenhagen, Lykkebækvej 1, 4600, Køge, Denmark.
| | - Clemence Chidziva
- University of Zimbabwe, Department of Surgery, 630 Churchill Avenue, Harare, Zimbabwe.
| | - Hasantha Gunasekera
- University of Sydney, Australia; The Children's Hospital at Westmead, Cnr Hawkesbury Rd &, Hainsworth St, Westmead, NSW, 2145, Australia.
| | - Kelvin Kong
- John Hunter Children's Hospital, Newcastle, Australia; Hunter ENT, Kookaburra Cct, New Lambton Heights, NSW, 2305, Australia.
| | - Mahmood F Bhutta
- Royal Sussex County Hospital, Eastern Road, Brighton BN2 5BE, UK.
| | - Ramon Jensen
- Dept of Oto-rhino-laryngology and Audiology, F 2071 Rigshospitalet, Blegdamsvej 9, DK, 2100, Denmark; Department of Clinical Medicine, Blegdamsvej 3, 2200, København, Denmark.
| | - Sharon Ovnat Tamir
- Dept of OTO-HNS, Samson Assuta Ashdod University Hospital, Ashdod, Israel; Department of Otolaryngology-Head and Neck Surgery, Assuta University Hospital, Israel; Faculty of Health Sciences, Ben Gurion University of the Negev, Ashdod, Israel.
| | - Sumon Kumar Das
- Menzies School of Health Research, John Mathews Building 58, Royal Darwin Hospital Campus, Rocklands Dr, Tiwi, NT, 0810, Australia.
| | - Peter Morris
- Menzies School of Health Research, John Mathews Building 58, Royal Darwin Hospital Campus, Rocklands Dr, Tiwi, NT, 0810, Australia; Royal Darwin Hospital, Rocklands Dr, Tiwi, NT, 0810, Australia.
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13
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Alternative therapy to manage otitis media caused by multidrug-resistant fungi. Arch Microbiol 2020; 202:1231-1240. [PMID: 32108246 DOI: 10.1007/s00203-020-01832-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2020] [Revised: 01/29/2020] [Accepted: 02/07/2020] [Indexed: 10/24/2022]
Abstract
During the last few decades, the increase in the incidence of multidrug-resistant (MDR) fungal infections has become an emerging threat to public health. Therefore, it is important to illuminate the usage of alternative therapy to treat MDR fungal infection. This study was carried out to elucidate the usage of plant extract and essential oil, either alone or with other antifungal drugs to treat otitis media caused by MDR fungi. Medicinal plant is a safe and cheap source when compared with chemical antifungal drugs. Twenty-one fungal isolates out of 104 ear swabs from patients suffering from otitis media were characterized using both phenotypic and genotypic methods. The antibiogram typing was used to determine the MDR isolates. The sensitivity of MDR fungal isolates was tested against several plant extracts and essential oils, either alone or with other antifungal drugs. Thyme oil and clove extracts proved to have synergistic effects suggesting their use in the treatment of fungal infections, especially otitis media caused by MDR fungi. The ultrastructure of MDR fungal isolates exhibited a complete destruction post exposure to the used materials when observed under the transmission microscope (TEM). Thyme oil and clove extract were found to be the most effective agents against MDR fungal isolates and they constitute a promising tool for the management of fungal infection causing the otitis media.
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14
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Emerging Fungal Infections: New Patients, New Patterns, and New Pathogens. J Fungi (Basel) 2019; 5:jof5030067. [PMID: 31330862 PMCID: PMC6787706 DOI: 10.3390/jof5030067] [Citation(s) in RCA: 181] [Impact Index Per Article: 36.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 07/18/2019] [Accepted: 07/19/2019] [Indexed: 01/13/2023] Open
Abstract
The landscape of clinical mycology is constantly changing. New therapies for malignant and autoimmune diseases have led to new risk factors for unusual mycoses. Invasive candidiasis is increasingly caused by non-albicans Candida spp., including C. auris, a multidrug-resistant yeast with the potential for nosocomial transmission that has rapidly spread globally. The use of mould-active antifungal prophylaxis in patients with cancer or transplantation has decreased the incidence of invasive fungal disease, but shifted the balance of mould disease in these patients to those from non-fumigatus Aspergillus species, Mucorales, and Scedosporium/Lomentospora spp. The agricultural application of triazole pesticides has driven an emergence of azole-resistant A. fumigatus in environmental and clinical isolates. The widespread use of topical antifungals with corticosteroids in India has resulted in Trichophyton mentagrophytes causing recalcitrant dermatophytosis. New dimorphic fungal pathogens have emerged, including Emergomyces, which cause disseminated mycoses globally, primarily in HIV infected patients, and Blastomyceshelicus and B. percursus, causes of atypical blastomycosis in western parts of North America and in Africa, respectively. In North America, regions of geographic risk for coccidioidomycosis, histoplasmosis, and blastomycosis have expanded, possibly related to climate change. In Brazil, zoonotic sporotrichosis caused by Sporothrix brasiliensis has emerged as an important disease of felines and people.
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15
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Triazole resistance in Aspergillus fumigatus: recent insights and challenges for patient management. Clin Microbiol Infect 2019; 25:799-806. [DOI: 10.1016/j.cmi.2018.11.027] [Citation(s) in RCA: 96] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Revised: 11/07/2018] [Accepted: 11/30/2018] [Indexed: 01/18/2023]
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17
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Molecular Tools for the Detection and Deduction of Azole Antifungal Drug Resistance Phenotypes in Aspergillus Species. Clin Microbiol Rev 2017; 30:1065-1091. [PMID: 28903985 DOI: 10.1128/cmr.00095-16] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The incidence of azole resistance in Aspergillus species has increased over the past years, most importantly for Aspergillus fumigatus. This is partially attributable to the global spread of only a few resistance alleles through the environment. Secondary resistance is a significant clinical concern, as invasive aspergillosis with drug-susceptible strains is already difficult to treat, and exclusion of azole-based antifungals from prophylaxis or first-line treatment of invasive aspergillosis in high-risk patients would dramatically limit drug choices, thus increasing mortality rates for immunocompromised patients. Management options for invasive aspergillosis caused by azole-resistant A. fumigatus strains were recently reevaluated by an international expert panel, which concluded that drug resistance testing of cultured isolates is highly indicated when antifungal therapy is intended. In geographical regions with a high environmental prevalence of azole-resistant strains, initial therapy should be guided by such analyses. More environmental and clinical screening studies are therefore needed to generate the local epidemiologic data if such measures are to be implemented on a sound basis. Here we propose a first workflow for evaluating isolates from screening studies, and we compile the MIC values correlating with individual amino acid substitutions in the products of cyp51 genes for interpretation of DNA sequencing data, especially in the absence of cultured isolates.
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Chowdhary A, Sharma C, Meis JF. Azole-Resistant Aspergillosis: Epidemiology, Molecular Mechanisms, and Treatment. J Infect Dis 2017; 216:S436-S444. [PMID: 28911045 DOI: 10.1093/infdis/jix210] [Citation(s) in RCA: 191] [Impact Index Per Article: 27.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Aspergillus fumigatus remains the most common species in all pulmonary syndromes, followed by Aspergillus flavus which is a common cause of allergic rhinosinusitis, postoperative aspergillosis and fungal keratitis. The manifestations of Aspergillus infections include invasive aspergillosis, chronic pulmonary aspergillosis and bronchitis. Allergic manifestations of inhaled Aspergillus include allergic bronchopulmonary aspergillosis and severe asthma with fungal sensitization. Triazoles are the mainstay of therapy against Aspergillus infections for treatment and prophylaxis. Lately, increased azole resistance in A. fumigatus has become a significant challenge in effective management of aspergillosis. Earlier studies have brought to light the contribution of non-cyp51 mutations along with alterations in cyp51A gene resulting in azole-resistant phenotypes of A. fumigatus. This review highlights the magnitude of azole-resistant aspergillosis and resistance mechanisms implicated in the development of azole-resistant A. fumigatus and address the therapeutic options available.
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Affiliation(s)
- Anuradha Chowdhary
- Department of Medical Mycology, Vallabhbhai Patel Chest Institute, University of Delhi, India
| | - Cheshta Sharma
- Department of Medical Mycology, Vallabhbhai Patel Chest Institute, University of Delhi, India
| | - Jacques F Meis
- Department of Medical Microbiology and Infectious Diseases, Canisius Wilhelmina Hospital.,Centre of Expertise in Mycology Radboudumc/Canisius Wilhelmina Hospital, Nijmegen, The Netherlands
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Ashu EE, Korfanty GA, Xu J. Evidence of unique genetic diversity in Aspergillus fumigatus isolates from Cameroon. Mycoses 2017; 60:739-748. [PMID: 28730597 DOI: 10.1111/myc.12655] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Revised: 03/19/2017] [Accepted: 06/20/2017] [Indexed: 11/27/2022]
Abstract
Aspergillus fumigatus is a saprophytic fungus that can cause lethal invasive aspergillosis in immunocompromised patients. Recent studies have shown that Eurasian and North American populations of A. fumigatus often consist of genetically diverse strains. However, very little is known about African populations of A. fumigatus. Here, we characterise the genetic diversity and triazole susceptibility of A. fumigatus in Cameroon, West Africa. A total of 495 soil samples were obtained from nine collection sites in three Cameroonian regions. Nine microsatellite markers were used to genotype all 51 identified A. fumigatus isolates. In vitro susceptibility to itraconazole and voriconazole was tested using micro broth dilution. The 51 Cameroonian A. fumigatus isolates belonged to 45 genotypes. Consistent with recombination, 32 of 36 possible pairwise loci combinations are phylogenetically incompatible. Interestingly, evidence for geographic sub-structuring was found within Cameroon and the sub-population with the most evidence of recombination was also the least susceptible sub-population to the triazole antifungals tested. Furthermore, the Cameroonian sample was significantly differentiated from those in Eurasia and North America. Overall, our results indicate the genetic uniqueness of Cameroonian A. fumigatus populations and that additional novel genetic diversity likely exist in other parts of Africa.
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Affiliation(s)
- Eta E Ashu
- Department of Biology, McMaster University, Hamilton, ON, Canada
| | | | - Jianping Xu
- Department of Biology, McMaster University, Hamilton, ON, Canada
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