PriMera Scientific Medicine and Public Health (ISSN: 2833-5627)

Review Article

Volume 7 Issue 3

Internal Transcribed Spacer Characterization and Molecular Detection of ERG2 gene Mutation in Clinical Isolates of Suspected Candida species at a Tertiary Hospital in Port Harcourt, Nigeria

Ogbonna UH, Tatfeng MY, John Elizabeth and Aaron UU*

August 31, 2025

View PDF

Abstract

Internal transcribed spacer (ITS) is a nonfunctional RNA located between structural ribosomal RNAs (rRNA) of a common precursor transcript. ITS sequence analysis provides species-level identification when routine testing is inadequate for optimal patient care. Studies in Nigeria have focused on the molecular characterization of Candida albicans and their resistance mechanisms, including ERG2 gene mutations. Clinical specimens were collected from various clinics and cultured on Sabouraud dextrose agar. After molecular characterization using PCR and sequencing, the results showed that females (91.4%) predominated among the 221 subjects analyzed, with the highest prevalence in high vaginal swabs (33.5%). Antifungal drug resistance was highest in the 21-30 years age group, with females showing greater resistance (72.1%) compared to males (8.5%). Molecular studies showed 20.7% of females harbored the ERG gene, while no males did. Molecular characterization was more significant than phenotypic, as not all phenotypically confirmed isolates were C. albicans. The study highlighted the importance of ITS testing for prompt diagnosis.

Keywords: Internal transcribed spacer (ITS); Candida albicans; ERG 2; Molecular; Port Harcourt

References

  1. Aaron UU, Abbey SD and Azuonwu O. “Antifungal Activity Assessment of Selected Locally Sold Over-The-Counter Azole against Candida albicans Isolates from Hospital and Community Settings of Rivers State, Nigeria”. Journal of Natural Sciences Research 7.9 (2017): 1102-111.
  2. Aaron UU, Abbey SD and Azuonwu O. “Comparative Analysis of Candida albicans Isolates Obtained from Hospital and Community Settings of Niger Delta, Nigeria”. EPRA International Journal of Advanced Research and Development 4.2 (2017): 24-31.
  3. Aaron UU, Abbey SD and Azuonwu O. “Antifungal Resistance Surveillance: A Tool Necessary for Monitoring Azole Resistance Potentials in Candida albicans Isolates from Niger Delta Communalities in Nigeria”. Current Studies in Comparative Education, Science and Technology 4.1 (2017): 81-93.
  4. Aboud S., et al. “Genital Tract Infections among HIV-Infected Pregnant Women in Malawi, Tanzania and Zambia”. International Journal of Sexually Transmitted Diseases and AIDS 19.12 (2008): 824-832.
  5. Akinbiyi AA, Watson R and Feyi-Waboso P. “Prevalence of Candida albicans albicans and Bacterial Vaginosis in Asymptomatic Pregnant Women in South Yorkshire. United Kingdom. Outcome of a prospective Study”. Archives of Gynecology and Obstetetrics 278.5 (2008): 463-466.
  6. Al-akeel RA., et al. “Prevalence and Comparison for Detection Methods of Candida albicans species in Vaginal Specimens from Pregnant and Non-Pregnant Saudi Women”. African Journal of Microbiology Research 7.1 (2013): 56-65.
  7. Bammert GF and Fostel JM. “Genome-Wide Expression Patterns in Saccharomyces cerevisiae: Comparison of Drug Treatments and Genetic Alterations Affecting Biosynthesis of Ergosterol”. Antimicrobial Agents and Chemotherpy 44 (2000): 1255-1265.
  8. Boehm J., et al. “Kex2-Dependent Invertase Secretion as a Tool to Study the Targeting of Transmembrane Proteins Which are Involved in ER-Golgi Transport in Yeast”. Embo Journal 13.16 (1994): 3696-3710.
  9. Chen C., et al. “An Iron Homeostasis Regulatory Circuit with Reciprocal Roles in Candida albicans albicans Commensalism and Pathogenesis”. Cell Host Microbe 10.2 (2011): 118-135.
  10. Chong PP., et al. “Genetic Relatedness of Candida albicans Strains Isolated from Women with Vaginal Candidiasis in Malaysia”. Journal of Medical Microbiology 52 (2003): 657-666.
  11. Ciardo DE., et al. “Internal Transcribed Spacer Sequencing versus Biochemical Profiling for Identification of Medically Important Yeasts”. Journal of Clinical Microbiology 44 (2006): 77-84.
  12. Daniel WW. “Biostatistics: A Foundation for Analysis in the Health Sciences”. 7 Edition (1999): 755.
  13. Erdogan A and Rao SS. “Small Intestinal Fungal Overgrowth”. Current Gastroenterology Reports 17.4 (2015): 16.
  14. Felsenstein J. “Confidence Limits on Phylogenies: An Approach using the Bootstrap”. Evolution 39 (1985): 783-791.
  15. Fernandes R, Viegas A and Cerqueira F. “Candida albicans species Distribution in Clinical Samples. Revista da Faculdade de Ciencias da Saude”. Porto: Edições Universidade Fernando Pessoa (2009): 264-271.
  16. Ga-Yeon K, Jae-Sik J and Jae KK. “Isolation Frequency Characteristics of Candida albicans species from Clinical Specimens”. Mycobiology 44.2 (2016): 99-104.
  17. Goehring RV. “Mims' Medical Microbiology”. 4th Edition (2008): 656.
  18. Gow NAR. “Microbe Profile: Candida albicans albicans: A Shape-Changing, Opportunistic Pathogenic Fungus of Humans”. Microbiology 163.8 (2017): 1145-1147.
  19. Jombo GA., et al. “Symptomatic Urogenital Candidiasis and Therapeutic Management on Women Taking Oral Contraceptive Pills”. Journal of Microbiology and Antimicrobials 2.9 (2010): 118-122.
  20. Jukes TH and Cantor CR. “Evolution of Protein Molecules”. Mammalian Protein Metabolism (1969): 21-132.
  21. Martins N., et al. “Candidiasis: Predisposing Factors, Prevention, Diagnosis and Alternative Treatment”. Mycopathologia 177.5-6 (2014): 223-240.
  22. Mohamadi J., et al. “Antifungal Drug Resistance Pattern of Candida albicans. Spp. Isolated from Vaginitis in Ilam-Iran during 2013-2014”. Bioinformation 11.4 (2015): 203-206.
  23. Mohamadi J., et al. “Antifungal Drug Resistance Pattern of Candida albicans. Spp. Isolated from Vaginitis in Ilam-Iran during 2013-2014”. Bioinformation 10 (2014): 667.
  24. Nagia MMA., et al. “Internal Transcribed Spacer for Identification of Yeast Species Isolated from Cancer Patients at the Isotope and Radiation Center, Khartoum, Sudan”. F1000Research 7.443 (2018): 1-14.
  25. Ringdahi EN. “Treatment of Recurrent Vulvovaginal Candidiasis”. Journal of American Family Physician 61 (2010): 3306-3312.
  26. Rosamond J and Allsop A. “Harnessing the Power of the Genome in the Search for New Antibiotics”. Science 287 (2000): 1973-1976.
  27. Schoch CL., et al. “Nuclear Ribosomal Internal Transcribed Spacer (ITS) Region as a Universal DNA Barcode Marker for Fungi”. Proceedings of the National Academy of Sciences of the United States of America 109.16 (2012): 6241-6246.
  28. Tavakoli M., et al. “Upregulation of the ERG11 Gene in Candida albicans krusei by Azoles”. Daru Journal Pharmaceutical Sciences 18.4 (2010): 276-280.
  29. Wang ZK., et al. “Review Article: Fungal Microbiota and Digestive Diseases”. Alimentary Pharmacology & Therapeutics 39.8 (2014): 751-766.
  30. Wang H., et al. “Rapid Detection of ERG11 Gene Mutations in Clinical Candida albicans albicans Isolates with Reduced Susceptibility to Fluconazole by Rolling Circle Amplification and DNA Sequencing”. BioMed Central Microbiology 9 (2009): 167.
  31. Wu Y., et al. “Microglia and amyloid precursor protein coordinate control of transient Candida cerebritis with memory deficits”. Nat Commun 10.1 (2019): 58.
  32. Mayer FL, Wilson D and Hube B. “Candida albicans pathogenicity mechanisms”. Virulence 4.2 (2013): 119-128.
  33. Ikenyi CL, Ekuma A and Atting I. “Antifungal susceptibility and detection of mutant EGR11 gene in vaginal Candida isolates in University of Uyo Teaching Hospital, Uyo, Nigeria”. African Journal of Clinical and Experimental Microbiology 21 (2020): 226-232.
  34. Victorio GB., et al. “Antifungal activity of caspofungin in experimental infective endocarditis caused by Candida albicans”. Mem Inst Oswaldo Cruz 112.5 (2017): 370-375.
  35. https://worldwidescience.org/topicpages/a/albicans+double+infection.html
  36. Jukes TH and Cantor CR. “Evolution of Protein Molecules”. Mammalian Protein Metabolism (1969): 21-132.
  37. Karl WH, Joseph TN and Thomas DE. “Upregulation of ERG Genes in Candida Species by Azoles and Other Sterol Biosynthesis Inhibitors”. Antimicrobial Agents Chemotherapy 44.10 (2000): 2693-2700.
  38. Shin HS, Park YB and Shin DS. “Isolation Frequency of Candida species from Clinical Specimens Kor”. Journal of Mycology 38 (2010): 146-151.