What are Fastidious Bacteria?
Fastidious bacteria are organisms that have complex or specific dietary needs. In other words, a simple creature will only survive if certain specific nutrients are present in its environment. In microbiology, the more restrictive term fastidious microbe is used to describe such bacteria that will only grow if those specific nutrients are present in their culture medium. Neisseria gonorrhoeae is one of the most common examples of fastidious bacteria that require blood or haemoglobin and many amino acids and vitamins to grow.
Fastidious organisms are not intrinsically "weak"-they may grow and thrive in their specific biological niche, with their specific nutrients, temperature, and lack of competition. They can be extremely difficult to eradicate. They are, however, difficult to cultivate since it is impossible to precisely recreate their natural environment in a cultural media. Treponema pallidum, for example, is difficult to cultivate yet persistent in its preferred habitat, making it difficult to remove from all tissues of a syphilis patient. Other examples are Campylobacter spp. and Helicobacter spp., both of which are capnophilic (need high levels of CO2) and have other needs.
Significance of Fastidious bacteria
One of the practical applications of fastidious bacteria is that sometimes a false negative result might come from a negative culture. This shows that the test's sensitivity is less than ideal. It means that just because the culturing could not prove the presence of an organism or identify the organism of interest does not imply that the organism is not present in the culturing sample.
Therefore, a clinician cannot state the presence of any fastidious bacteria like pneumonia or sepsis just by analyzing its presence through culturing in the patient's sample. This does not mean culturing is inefficient and should not be employed. Instead, it means that culturing alone is not sufficient to prove bacteria's presence, and hence, the antibiotic to be given to the patient cannot be determined.
To identify the presence of bacteria or fungus in the patient's sample, scientists and clinicians use several other techniques and cultures. These techniques are:
The Immunological test is more promising along with culturing than the nucleic acid test because the presence of DNA and RNA of microbes is already prevalent in the atmosphere and can result in wrong interpretations.
As a result, a positive result on such tests might occasionally be a false positive due to the critical contrast between infection and colonization or ungerminated spores. (The same issue creates perplexing mistakes in DNA testing in forensics; minute bits of one's DNA can get up practically everywhere, such as via fomites transfer. Since contemporary techniques can recover such little amounts, it requires caution to interpret their existence). This is why competence is required to determine which test to apply in a specific scenario and interpret the findings.
Types of Fastidiousness
The requirements of some microbial species are not limited to just specific nutrients but also numerous chemical signals, some of which are dependent, both directly and indirectly, on the presence of other species. Thus, nutritional needs and other chemical requirements might prevent species from being cultured in isolation.
Fastidiousness and the difficulty of growing isolates were placed into logical context by Lewis Thomas in his 1974 book Lives of a Cell: Formalized paraphrase "It is believed that we only know about a small percentage of the earth's bacteria since most of them cannot be cultured on their own. They live in dense, interconnected groups, feeding and sustaining on one another while controlling population balance between various species via a sophisticated system of chemical signals".
One logical corollary of this statement is that many species' inseparability from their original ecological settings is normal and reflects just the prevalence of interdependencies in ecological systems. It does not reflect any species' fragility, frailty, stubbornness, or rarity.
Another set of data is pertinent to Lewis' statement regarding the limits of humans' ability to acquire a deeper understanding of microbes-from individual species and strains to entire microbial ecosystems.
With the advancement of technology, especially in data science, there is an extensive development in omics. Different omics include; microbiomics, metabolomics, and metagenomics, which can be used to determine the relationship of the microbial world with the environment. This is quite successful because of the increasing advancement of high throughput sequencing technology. Sequencing has made it possible to analyze the microbial population to the next level through digital analysis. It has expanded humans' ability to understand the microbial world, their biochemical behaviour, and their footprints. Using these techniques and primary techniques (culturing and assays) will give more insight into the life of these fastidious bacteria.