Acta Scientific Microbiology (ISSN: 2581-3226)

Research Article Volume 5 Issue 10

Aerobic Microbiota of Neem (Azadirachta indica) Leaves: Possible Risks of Chewing Raw Neem Leaves

Bhoj R Singh*, Akanksha Yadav, Sinha DK, Vinodh Kumar OR and Karthikeyan R

Division of Epidemiology, ICAR-Indian Veterinary Research Institute, Izatnagar, India

*Corresponding Author: Bhoj R Singh, Principal Scientist, Division of Epidemiology, Modular Laboratory Building, ICAR-Indian Veterinary Research Institute, Izatnagar, India.

Received: August 19, 2022; Published:September 30, 2022


Raw Neem (Azadirachta indica) leaves’ chewing is an often-recommended healthy practice in India, but little is understood about the microbial quality of leaves chewed. This study conducted to analyse the presence of potential microbiological hazards associated with Neem leaves. It was assessed through detection and antimicrobial resistance (A.M.R.) profiling of different aerobically growing bacteria using standard bacteriological methods. A total of 110 samples of Neem leaves collected from four localities (IVRI = 62, CARI = 10, Mahanagar = 18, and Suncity = 20) analysed yielded 357 bacterial isolates belonging to more than 63 species of 24 genera. Isolation of Gram-negative bacteria from samples of IVRI and CARI was significantly more frequent (p, < 0.05) than those from Mahanagar and Suncity, while the picture was in reverse for Gram-positive bacteria isolates. The most prevalent potentially pathogenic bacteria included Enterobacter (Pantoea) agglomerans detected in 37 samples, followed by Hafnia alvei (20), Escherichia coli (11), Serratia marcescens (8), Bacillus cereus (7), Raoultella terrigena (7), Serratia odorifera (7), Aeromonas bestiarum (4), Enterococcus faecium (2), Klebsiella oxytoca (2), K. pneumoniae (1), Pseudomonas aeruginosa (2), Acinetobacter ewofflii (1), Aeromonas caviae (1), Proteus mirabilis (1), Stenotrophomonas multophila (1), and Pseudomonas pseudoalcaligenes (1). In 26 samples, carbapenem-resistant (CR) and 72 samples, extended-spectrum β-lactamase (ESBL) producing bacteria were detected. Herbal antimicrobial drug resistance was also seen in a large number of bacterial isolates. The study indicated that A. indica leaves may be harbouring potentially pathogenic multiple drug-resistant bacteria, which may harm the health of leaves' consumers. Therefore, it may be suggested that a fresh A. indica leaves should only be consumed after proper cleansing and decontamination.

Keywords: Aerobic Microbiome; Microbiota of Neem Leaves; Escherichia coli; Carbapenem Resistance; ESBL; M.D.R; Klebsiella; Aeromonas; Enterococcus faecium


  1. Singh AK., et al. “Isolation, morphological identification and in vitro antibacterial activity of endophytic bacteria isolated from Azadirachta indica (Neem) leaves”. Veterinary World 10 (2017): 510-516.
  2. Strobel G and Daisy B. “Bioprospecting for microbial endophytes and their natural products”. Microbiology and Molecular Biology Reviews 67 (2003): 491-502.
  3. Upma A., et al. “The nature’s gift to mankind: Neem”. International Research Journal of Pharmacy 2 (2011): 13-15.
  4. Elavarasu S., et al. “Evaluation of anti-plaque microbial activity of Azadirachta indica (Neem oil) in vitro: A pilot study”. Journal of Pharmacy and Bioallied Sciences 4 (2012): S394.
  5. Xu J., et al. “Antiviral activity and mode of action of extracts from Neem seed kernel against duck plague virus in vitro”. Poultry Science 91 (2012): 2802-2807.
  6. Alam A., et al. “Novel anti-inflammatory activity of epoxyazadiradione against macrophage migration inhibitory factor: inhibition of tautomerase and proinflammatory activities of macrophage migration inhibitory factor”. The Journal of Biological Chemistry 287 (2012): 24844-24861.
  7. Abdel-Ghaffar F., et al. “Efficacy of a single treatment of head lice with a Neem seed extract: an in vivo and in vitro study on nits and motile stages”. Parasitology Research 110 (2012: 277-280.
  8. Aravindan S., et al. “Molecular basis of ‘hypoxic’ breast cancer cell radio-sensitization: phytochemicals converge on radiation induced Rel signaling”. Radiation Oncology 8 (2013): 1-12.
  9. Ebrahimi A., et al. “Antimicrobial activities of isolated endophytes from some Iranian native medicinal plants”. Iranian Journal of Pharmaceutical Science 6 (2010): 217-222.
  10. Jalgaonwala RE., et al. “Evaluation of endophytes for their antimicrobial activity from indigenous medicinal plants belonging to North Maharashtra region India”. International Journal of Pharmacy and Biomedical Research 1 (2010): 136-141.
  11. Pal A., et al. “Diversity and antimicrobial spectrum of endophytic bacteria isolated from Paederia foetida L”. International Journal of Current Pharmaceutical Research 4 (2012): 123-127.
  12. Roy S and Banerjee D. “Isolation of antimicrobial compound by endophytic bacteria from Vinca rosea”. International Journal of Curreent Research 5 (2010): 47-51.
  13. Verma VC., et al. “Endophytic actinomycetes from Azadirachta indica Juss.: isolation, diversity, and anti-microbial activity”. Microbial Ecology 57 (2009): 749-756.
  14. Chaurasia SC and Jain PC. “Antibacterial activity of essential oils of four medicinal plants”. Indian Journal of Hospital Pharmacy 15 (1978): 166-168.
  15. Rao DVK. “In vitro antibacterial activity of Neem oil”. Indian Journal of Medical Research 84 (1986): 314-316.
  16. Jahan T., et al. “Effect of Neem oil on some pathogenic bacteria”. Bangladesh Journal of Pharmacology 2 (2007): 71-72.
  17. Khan SA and Aslam J. “Study on the effect of Neem (Azadirachta indica) leaves smoke in controlling airborne bacteria in residential premises”. Current Research in Bacteriology 1 (2010): 64-66.
  18. Srivastava SK. “Symptoms of a bacterial disease of Neem”. PANS Pest Articles and News Summaries 16 (1970): 518-521.
  19. Baby AR., et al. “Azadirachta indica (Neem) as a potential natural active for dermocosmetic and topical products: A narrative review”. Cosmetics 9 (2022): 58.
  20. Sengupta S. “Amazing benefits of chewing Neem regularly”. NDTV Food (2021).
  21. Murthy GS., et al. “Effect of chewing Azadirachta indica (Neem) and Ocimum sanctum (tulsi) leaves on salivary acidogenicity: A comparative study”. Journal of Oral Maxillofacial Pathology 24 (2020): 479-483.
  22. Purohit H. “Amazing benefits of eating neem leaves on empty stomach”. Sehat (2019).
  23. Carter GR. “Diagnostic Procedures in Veterinary Microbiology”. 2nd edn, Charles C Thomas Publishers: Springfield (1975).
  24. Bergey D., et al. “Bergey's manual of determinative bacteriology”. William and Wilkins, Baltimore, MD. Bergey's manual of determinative bacteriology. 9th Williams and Wilkins, Baltimore, MA. (1994).
  25. Singh BR. “Labtop for Microbiology Laboratory”. Lamber t Academic Publishing, AG and Co. KG, Berlin, Germany (2009).
  26. Clinical and Laboratory Standards Institute. “Performance standards for antimicrobial disk susceptibility tests”. Clinical and Laboratory Standards Institute, Wayne, USA (2014).
  27. Clinical and Laboratory Standards Institute. “Methods for Antimicrobial Dilution and Disk Susceptibility Testing of Infrequently Isolated or Fastidious Bacteria”. M45, 3rd Clinical and Laboratory Standards Institute, Wayne, USA (2015).
  28. Singh BR., et al. “Antimicrobial activity of lemongrass (Cymbopogon citratus) oil against microbes of environmental, clinical and food origin”. International Research Journal of Pharmacy and Pharmacology 1 (2011): 228-236.
  29. Govindasamy V., et al. “Bacillus and Paenibacillus : potential PGPR for sustainable agriculture, plant growth and health promoting bacteria”. Microbiology Monographs. Springer (2010): 333-364.
  30. Zulkhairi A., et al. “Probiotic properties of Bacillus strains isolated from stingless bee (Heterotrigona itama) honey collected across Malaysia”. International Journal of Environmental Research (Public Health) 17 (2020): 278.
  31. “Technical brief on water, sanitation, hygiene (WASH) and wastewater management to prevent infections and reduce the spread of antimicrobial resistance (AMR)”. In: World Health Organization, F.A.O., World Organization for Animal Health (Ed.), Global Coordination and Partnership, Surveillance, Prevention and Control, Water, Sanitation, Hygiene and Health. World Health Organization (2020).
  32. Singh BR., et al. “A bakery product associated Bacillus cereus food poisoning outbreak”. Indian Journal of Comparative Microbiology Immunology and Infectious Disease 16 (1996): 151-152.
  33. Wenzler E., et al. “Severe sepsis secondary to persistent Lysinibacillus sphaericus, Lysinibacillus fusiformis and Paenibacillus amylolyticus bacteremia”. International Journal of Infectious Diseases 35 (2015): 93-95.
  34. Singh BR. “ESKAPE pathogens in animals and their antimicrobial drug resistance pattern”. Journal Dairy, Veterinary and Animals 7 (2018): 1-10.
  35. Rungsirivanich P., et al. “Culturable bacterial community on leaves of assam tea (Camellia sinensis assamica) in Thailand and human probiotic potential of isolated Bacillus spp”. Microorganisms 8 (2020): 1585.
  36. Starr MP and Chatterjee AK. “The genus Erwinia: Enterobacteria pathogenic to plants and animals”. Annual Review of Microbiology 26 (1972): 389-426.
  37. Clifton IJ and Peckham DG. “Defining routes of airborne transmission of Pseudomonas aeruginosa in people with cystic fibrosis”. Expert Review of Respiratory Medicine 4 (2010): 519-529.
  38. Singh BR., et al. “An orange juice-borne diarrhoeal outbreak due to enterotoxigenic Escherichia coli”. Journal of Food Science and Technology 32 (1995): 504-506.
  39. Nirupama KR., et al. “Molecular characterisation of blaOXA-48 carbapenemase-, extended-spectrum beta-lactamase- and Shiga toxin-producing Escherichia coli isolated from farm piglets in India”. Journal of Global Antimicrobial Resistance 13 (2018): 201-205.
  40. Singh BR and Singh SV. “Metallo-β-lactamase and extended-spectrum-β-lactamase production by Serratia strains”. Infection and Drug Resistance 13 (2020): 1295-1297.
  41. Singh BR., et al. “Potential of herbal antibacterials as an alternative to antibiotics for multiple drug resistant bacteria: An analysis”. Research Journal of Veterinary Science 13 (2020): 1-8.
  42. Kumar S and Singh BR. “An overview of mechanisms and emergence of antimicrobials drug resistance”. Advances in Animal and Veterinary Sciences2S (2013): 7-14.


Citation: Bhoj R Singh., et al. “Aerobic Microbiota of Neem (Azadirachta indica) Leaves: Possible Risks of Chewing Raw Neem Leaves". Acta Scientific Microbiology 5.10 (2022): 68-86.


Copyright: © 2022 Bhoj R Singh., et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.


Acceptance rate30%
Acceptance to publication20-30 days

Indexed In

News and Events

  • Certification for Review
    Acta Scientific certifies the Editors/reviewers for their review done towards the assigned articles of the respective journals.
  • Submission Timeline for Upcoming Issue
    The last date for submission of articles for regular Issues is July 30, 2024.
  • Publication Certificate
    Authors will be issued a "Publication Certificate" as a mark of appreciation for publishing their work.
  • Best Article of the Issue
    The Editors will elect one Best Article after each issue release. The authors of this article will be provided with a certificate of "Best Article of the Issue"
  • Welcoming Article Submission
    Acta Scientific delightfully welcomes active researchers for submission of articles towards the upcoming issue of respective journals.

Contact US