Fastidious bacteria are those that live on complex nutrition and need a special requirement for their growth.
Nutrient agar is the simple media in which all the bacteria can grow easily, but fastidious bacteria require complex nutrition. They have many other factors to grow properly. They can’t grow in the absence of that factor. These bacteria are difficult to isolate and grow. These factors vary from bacteria to bacteria. This factor depends on the physiology of bacteria.
Campylobacter jejuni needs 5% O2 instead of 20% oxygen to grow. It is micro-aerophillic bacteria and used to grow at 5% oxygen level. If there is more than 5% of O2 level, these bacteria stop its growth.
Hemophillus influenza is also a fastidious bacterium that needs factor X (heme) and factor Y (NAD) for its growth. These bacteria grow in chocolate agar because at 80ºC blood components break. When blood components break, heme and NAD become free for utilization. Hemophillus influenza used that factors and start growing.
Neisseria gonorrhea doesn’t grow on blood agar because blood has fatty acids and minerals that inhibit the growth of this bacterium. When blood agar is changed into chocolate agar, fatty acids and mineral of blood agar break and allows bacteria to grow.
Legionella pneumophilla is a fastidious bacterium because it needs iron and cysteine for its growth
How to grow these bacteria?
It is necessary to know the requirement of the bacteria. Rather than this, selective media is also available that have its entire requirement for the growth of bacteria.
Demerits of fastidious bacteria:
Many of the fastidious bacteria are opportunistic pathogen. They produce many diseases e.g.
Campylobacter jejuni cause enteritis, bacteremia.
Hemophillus influenza causes meningitis, conjunctivitis, otitis media, sinusitis, pneumonia.
Neisseria gonorrhea causes meningitis, meningococcemia
Legionella pneumophilla causes pneumonia.
They cause severe disease in humans and also in animals. It is very difficult to grow and identified them as they are slow growing bacteria. That’s why it’s a big issue to deal with their sample.
Nowadays, scientist have designed the rapid test for their diagnosis that must contain
- Rapid agglutination test