Non-culturable Pathogenic Bacteria: Challenge to Lab Diagnosis

Last updated on June 21st, 2021

Culture is one of the most widely used laboratory diagnostic tools. Culture helps microbiologists in the identification and characterization of the causative agents of the disease. To perform antimicrobial susceptibility tests, microbiologists have to grow the bacteria in the laboratory media (though now antimicrobial resistance can be assessed better by molecular diagnostic tools).  

Due to the specific nutritional requirements of bacteria, a single media can not support the growth of all be bacteria so there are various bacteriologic media to help for the growth of specific bacteria. But still, there are some bacteria that can not be cultured (or grown) in the bacteriologic media available to date:  

  • T. pallidum has not yet been grown in bacteriologic media or in cell culture (but non-pathogenic treponemes can be cultured). Diagnosis is made by microscopy and serology.
Nine banded armadillo
Nine banded armadillo
  • M. leprae has not yet been grown in the laboratory either on artificial media or in cell culture. It can be grown in the mouse footpad or in the armadillo.
  • Chlamydia trachomatis can not be grown in an artificial medium but most grow in living cells. 

Bacteria that can be cultured: but rarely cultured in standard clinical laboratory

  • Coxiella burnetti (causative agent of Q Fever): Risk of Laboratory acquired infections is very high. Cultivation of Coxiella burnetti must be done in a bio-safety level 3 containment facility (facility not available in a standard clinical laboratory).
  • Rickettsia (they are the fastidious bacteria that are obligate, intracellular parasite), and causes Rickettsial pox, Rocky Mountain Spotted fever, typhus fever: They can be cultured in embryonated egg or tissue culture, the risk of laboratory-acquired infection is extremely high, so culture has rarely done.
About Acharya Tankeshwar 474 Articles
Hello, thank you for visiting my blog. I am Tankeshwar Acharya. Blogging is my passion. I am working as an Asst. Professor and Microbiologist at Department of Microbiology and Immunology, Patan Academy of Health Sciences, Nepal. If you want me to write about any posts that you found confusing/difficult, please mention in the comments below.

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