KUALA LUMPUR: Bacteria that cause diseases like diphtheria are constantly evolving to survive, and doing so will increase their virulence, says a medical expert.
It was reported that Health Minister Datuk Seri Dr S. Subramaniam had tasked the Institute for Medical Research (IMR) with finding out why those who have been vaccinated were contracting diphtheria.
Health deputy director-general (Medical) Datuk Dr S. Jeyaindran was reported as saying that before this, if one was vaccinated as a child, he would be safe from the bacteria as an adult.
“But now, even vaccinated adults have caught the bacteria,” he said. With the death of a 11-month-old boy from diphtheria in Kedah yesterday, the search for answers is becoming more urgent.
IMR has taken samples from diphtheria patients to study if there was a new strain of the bacteria causing the disease.
IMR director Datuk Dr Fadzilah Kamaludin said diphtheria was caused by bacteria, and they could boost their defences by, among others, changing their cell-wall components, produce toxins or produce destructive enzymes. “All these can occur by mutations in the chromosome of the bacteria.
The bacteria can also acquire genetic materials that carry virulent genes from other bacteria.
“This genetic material will integrate into the bacterial chromosomes,” she told the New Straits Times.
Dr Fadzilah said the main purpose of a bacterium’s existence was to survive, and changing their genetic material was one way to boost their virulent factors.
“The virulent factors will help the bacteria to invade the host, cause diseases and evade the host’s defences.”
Examples of virulent factors are the bacterium’s ability to adhere to the mucosal surface; the ability to invade host cells; and defend themselves against cells that protect the host body from harmful foreign particles.
Virulent factors also include endotoxins — toxins in the cell walls of some bacteria that can cause fever, changes in blood pressure, inflammation and shock.
There are also exotoxins — toxic enzymes produced or secreted from the bacteria. “Bacteria have existed earlier than humans, and evolving is a process that ensures their survival.
“Therefore, we cannot tell for sure how many bacteria have mutated,” Dr Fadzilah said.-nst
