Iranian Journal of Medical Sciences

Document Type : Original Article(s)

Authors

1 Department of Pathobiology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran

2 Department of Research and Development, Production and Research Complex, Pasteur Institute of Iran, Tehran, Iran

3 Department of Microbiology and Immunology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran

4 Department of Microbiology, Islamic Azad University Medical Branch of Tehran, Tehran, Iran

10.30476/ijms.2025.106890.4138

Abstract

Background: In general, human immunodeficiency virus (HIV) weakens the immune system, making patients prone to oral infections such as gum and dental diseases. Filamentous bacteria (actinomycetes) can multiply in these patients, leading to treatment-resistant infections. Routine antimicrobial drugs such as penicillin G, amoxicillin, and tetracycline are widely used for treatment. However, antibiotic resistance is rapidly increasing worldwide. Therefore, the major target of the present study was to assess the prevalence and antibiotic susceptibility of filamentous bacteria in the oral cavity of HIV-positive patients in Tehran, Iran.
Methods: In this cross-sectional study, oral swabs were collected from 205 HIV-positive patients in an academic behavioral disease clinic, Tehran, Iran, and immediately transported to the laboratory under cold chain conditions. Bacterial cultures were prepared on differentiate media, and primary identification was carried out using biochemical and microscopic assays. Furthermore, deoxyribonucleic acid (DNA) extraction was carried out for molecular identification of the bacterial isolates using 16S rRNA (ribosomal ribonucleic acid) sequencing and polymerase chain reaction (PCR). Antimicrobial susceptibility of the isolates was assessed using the disk diffusion method for selected antimicrobials.
Results: In general, filamentous bacteria were identified in 5.3% of HIV-positive patients, including Nocardia (2.9%) and Streptomyces (2.4%) species. Molecular identification and biochemical assessments verified these findings. The highest prevalence rate of the bacteria was observed in males (74.1%) and individuals aged 41–60 years. Phylogenetic analysis revealed significant genetic similarities in the identified strains. These bacteria were susceptible to trimethoprim-sulfamethoxazole but resistant to other antimicrobials.
Conclusion: In conclusion, filamentous bacteria such as Nocardia and Streptomyces species show high prevalence rates in HIV-positive patients. Accurate identification using molecular techniques and antimicrobial susceptibility assessments can improve infection management, thereby bringing patients’ relief. This study highlights the importance of early detection and suggests further studies on the prevalence and resistance patterns of filamentous bacteria in HIV-positive patients.

Highlights

Omid Narimani (Google Scholar)
Golshid Javdani Shahedin (Google Scholar)
Ramin Mazaheri Nezhad Fard (Google Scholar)

Keywords

  1. Gandhi RT, Landovitz RJ, Sax PE, Smith DM, Springer SA, Gunthard HF, et al. Antiretroviral Drugs for Treatment and Prevention of HIV in Adults: 2024 Recommendations of the International Antiviral Society-USA Panel. JAMA. 2025;333:609-28. doi: 10.1001/jama.2024.24543. PubMed PMID: 39616604.
  2. Djawe K, Buchacz K, Hsu L, Chen MJ, Selik RM, Rose C, et al. Mortality Risk After AIDS-Defining Opportunistic Illness Among HIV-Infected Persons--San Francisco, 1981-2012. J Infect Dis. 2015;212:1366-75. doi: 10.1093/infdis/jiv235. PubMed PMID: 26044289; PubMed Central PMCID: PMC11323282.
  3. Coker MO, Cairo C, Garzino-Demo A. HIV-Associated Interactions Between Oral Microbiota and Mucosal Immune Cells: Knowledge Gaps and Future Directions. Front Immunol. 2021;12:676669. doi: 10.3389/fimmu.2021.676669. PubMed PMID: 34616391; PubMed Central PMCID: PMC8488204.
  4. Marsh PD. In Sickness and in Health-What Does the Oral Microbiome Mean to Us? An Ecological Perspective. Adv Dent Res. 2018;29:60-5. doi: 10.1177/0022034517735295. PubMed PMID: 29355410.
  5. Zhang Y, Wang X, Li H, Ni C, Du Z, Yan F. Human oral microbiota and its modulation for oral health. Biomed Pharmacother. 2018;99:883-93. doi: 10.1016/j.biopha.2018.01.146. PubMed PMID: 29710488.
  6. Samaranayake L, Matsubara VH. Normal Oral Flora and the Oral Ecosystem. Dent Clin North Am. 2017;61:199-215. doi: 10.1016/j.cden.2016.11.002. PubMed PMID: 28317562.
  7. Belstrom D. The salivary microbiota in health and disease. J Oral Microbiol. 2020;12:1723975. doi: 10.1080/20002297.2020.1723975. PubMed PMID: 32128039; PubMed Central PMCID: PMC7034443.
  8. Heron SE, Elahi S. HIV Infection and Compromised Mucosal Immunity: Oral Manifestations and Systemic Inflammation. Front Immunol. 2017;8:241. doi: 10.3389/fimmu.2017.00241. PubMed PMID: 28326084; PubMed Central PMCID: PMC5339276.
  9. Zapun A, Vernet T, Pinho MG. The different shapes of cocci. FEMS Microbiol Rev. 2008;32:345-60. doi: 10.1111/j.1574-6976.2007.00098.x. PubMed PMID: 18266741.
  10. Valour F, Senechal A, Dupieux C, Karsenty J, Lustig S, Breton P, et al. Actinomycosis: etiology, clinical features, diagnosis, treatment, and management. Infect Drug Resist. 2014;7:183-97. doi: 10.2147/IDR.S39601. PubMed PMID: 25045274; PubMed Central PMCID: PMC4094581.
  11. Mabeza GF, Macfarlane J. Pulmonary actinomycosis. Eur Respir J. 2003;21:545-51. doi: 10.1183/09031936.03.00089103. PubMed PMID: 12662015.
  12. Nikolaidis M, Hesketh A, Frangou N, Mossialos D, Van de Peer Y, Oliver SG, et al. A panoramic view of the genomic landscape of the genus Streptomyces. Microb Genom. 2023;9. doi: 10.1099/mgen.0.001028. PubMed PMID: 37266990; PubMed Central PMCID: PMC10327506.
  13. Chater KF. Morphological and physiological differentiation in Streptomyces. Microbial development. 1984:89-116.
  14. Mehta HH, Shamoo Y. Pathogenic Nocardia: A diverse genus of emerging pathogens or just poorly recognized? PLoS Pathog. 2020;16:e1008280. doi: 10.1371/journal.ppat.1008280. PubMed PMID: 32134995; PubMed Central PMCID: PMC7058287.
  15. Das AK, Nandy S, Dudeja M, Tiwari R, Alam S. The incidence of nocardiosis at pulmonary and extra - pulmonary sites. J Clin Diagn Res. 2013;7:1427-9. doi: 10.7860/JCDR/2013/5177.3152. PubMed PMID: 23998082; PubMed Central PMCID: PMC3749652.
  16. Silva CL, Tincani I, Brandao Filho SL, Faccioli LH. Mouse cachexia induced by trehalose dimycolate from Nocardia asteroides. J Gen Microbiol. 1988;134:1629-33. doi: 10.1099/00221287-134-6-1629. PubMed PMID: 3065451.
  17. Frieri M, Kumar K, Boutin A. Antibiotic resistance. J Infect Public Health. 2017;10:369-78. doi: 10.1016/j.jiph.2016.08.007. PubMed PMID: 27616769.
  18. Woods GL, Brown-Elliott BA, Conville PS, Desmond EP, Hall GS, Lin G, et al. Susceptibility Testing of Mycobacteria, Nocardiae, and Other Aerobic Actinomycetes. CLSI Standards: Guidelines for Health Care Excellence. 2nd ed. New Jersey: Wayne; 2011. doi: 10.1128/9781555816728.ch73. PubMed PMID: 31339680.
  19. Khan Z, Al-Sayer H, Chugh TD, Chandy R, Provost F, Boiron P. Antimicrobial susceptibility profile of soil isolates of Nocardia asteroides from Kuwait. Clin Microbiol Infect. 2000;6:94-8. doi: 10.1046/j.1469-0691.2000.00026.x. PubMed PMID: 11168079.
  20. Kotrbova L, Lara AC, Corretto E, Scharfen J, Ulmann V, Petrickova K, et al. Evaluation and comparison of antibiotic susceptibility profiles of Streptomyces spp. from clinical specimens revealed common and region-dependent resistance patterns. Sci Rep. 2022;12:9353. doi: 10.1038/s41598-022-13094-4. PubMed PMID: 35672429; PubMed Central PMCID: PMC9174267.
  21. Ambaye A, Kohner PC, Wollan PC, Roberts KL, Roberts GD, Cockerill FR, 3rd. Comparison of agar dilution, broth microdilution, disk diffusion, E-test, and BACTEC radiometric methods for antimicrobial susceptibility testing of clinical isolates of the Nocardia asteroides complex. J Clin Microbiol. 1997;35:847-52. doi: 10.1128/jcm.35.4.847-852.1997. PubMed PMID: 9157140; PubMed Central PMCID: PMC229688.
  22. World Health Organization. Global antimicrobial resistance and use surveillance system (GLASS) report 2022. Geneva: WHO; 2022.
  23. Steinbrink J, Leavens J, Kauffman CA, Miceli MH. Manifestations and outcomes of nocardia infections: Comparison of immunocompromised and nonimmunocompromised adult patients. Medicine (Baltimore). 2018;97:e12436. doi: 10.1097/MD.0000000000012436. PubMed PMID: 30290600; PubMed Central PMCID: PMC6200467.
  24. Abbasian L, Dehghan Manshadi S, Hassan Nezhad M, Masoumzadeh N, Ghaderkhani S, Keyvanfar A. A Case Report of Disseminated Nocardiosis in a Patient with HIV Infection: Concurrent Liver, Pulmonary, and Brain Involvements. Arch Clin Infect Dis. 2024;19:e140527. doi: 10.5812/archcid-140527.
  25. Kulis E, Cvitkovic I, Pavlovic N, Kumric M, Rusic D, Bozic J. A Comprehensive Review of Antibiotic Resistance in the Oral Microbiota: Mechanisms, Drivers, and Emerging Therapeutic Strategies. Antibiotics (Basel). 2025;14. doi: 10.3390/antibiotics14080828. PubMed PMID: 40868022; PubMed Central PMCID: PMC12382797.
  26. Tsuzukibashi O, Fukatsu A, Fuchigami M, Uchibori S, Komine C, Umezawa K, et al. Isolation and identification methods for Actinomyces israelii involved in actinomycosis. Open J Stomatol. 2022;12:108-18. doi: 10.4236/ojst.2022.124011.
  27. Salehipour M, Zaker Bostanabad S, Rezaee S, Hashemi-Shahraki A. Antimicrobial susceptibility of clinical isolates of Nocardia in Iran. New Cell Mol Biotechnol J. 2016;6:99-106.