With bacteria against hospital germs

Researchers are developing new bioweapon against resistant germs in clinics

17/08/2011

In the fight against resistant hospital germs, physicians may soon be able to resort to a new weapon. Researchers at the Nanyang Technological University in Singapore have designed a killer bacterium that attacks and destroys the resistant pathogens.

The scientists used an intestinal bacterium and genetically modified it into a bio-weapon against resistant hospital germs. Like Matthew Wook Chang of Nanyang Technological University in Singapore and colleagues in the journal „Molecular Systems Biology“ reported, the killer bacteria in the previous studies proved to be extremely effective in the control of antibiotic-resistant bacteria of the genus Pseudomonas aeruginosa.

Biowaffe against resistant hospital germs
The scientists around Matthew Wook Chang have converted a harmless variant of the Escherichia coli bacteria using genetic methods of so-called synthetic biology into a bioweapon, which should help in the fight against dangerous hospital germs. According to the researchers, they felt „Escherichia coli bacteria mutated and killed the solution-floating Pseudomonas bacteria.“ There is one „Reduction of viable cells by 99 percent“ Wook Chang and colleagues report. In addition, with the help of genetically modified bacteria, it is also possible to prevent the formation of so-called biofilms, which enable the survival of Pseudomonas bacteria outside the organism - for example on devices or smooth surfaces in the hospital - according to the researchers in the journal „Molecular Systems Biology“. Accordingly, the newly developed bacteria in laboratory experiments also in such biofilms of Pseudomonas aeruginosa as extremely effective weapon and reduced the biofilm formation by about 90 percent. According to the experts, the formation of biofilms is considered to be the main reason for the transmission of life-threatening hospital germs, since the protective mucus layer contributes to the survival of the Pseudomonas aeruginosa bacteria relatively long outside the organism.

Synthetic biology enables novel treatments
The scientists from Nanyang Technological University in Singapore have upgraded Escherichia coli to true killer bacteria using synthetic biology techniques. Wook Chang and colleagues used various genetic components of biological structures to combine them specifically for the fight against hospital germs. With the help of a built-in biological sensor, which registers the chemical messengers that Pseudomonas germs use for communication, the killer bacteria can locate the hospital germs. Subsequently, another artificially implemented mechanism triggers increased poison production in the modified Escherichia coli bacterium, whereupon the carrier bacterium bursts and releases a deadly poison specifically for microbes. The nearby hospital germs are killed immediately upon contact with the poison.

Further investigations required
Overall, the novel method for combating resistant hospital germs with the help of genetically modified Escherichia coli bacteria has so far been extremely efficient, but it must be reviewed in further studies, the researchers report. The approach of using engineered Escherichia coli bacteria against Pseudomonas aeruginosa, however, offers a novel, synthetic biology-based, antimicrobial strategy to eradicate infectious agents that could also be transmitted to other resistant bacteria, according to the researchers. However, as no studies have been done on the living organism yet, it is difficult to predict what effect the novel bioweapon might have on the body. According to the plans of the researchers, this will be examined in more detail in future studies with infected mice, in which the manipulated bacteria can prove their efficiency even in the living organism.

Resistant pathogens on the rise - research lags behind
Researchers in the field of multidrug-resistant pathogens such as Pseudomonas aeruginosa find that there is an urgent need to catch up with researchers led by Matthew Wook Chang. Although more and more germs have now developed resistance to antibiotics and antibiotics as the previous all-purpose weapon for the treatment of bacterial infections is visibly losing its effect, the research lags behind. In the case of the resistant hospital germs, the so-called rodent bacterium of the genus Pseudomonas aeruginosa is one of the most common causes of serious hospital infections besides the relatively widespread multidrug-resistant staphylococci (methicillin-resistant Staphylococcus aureus, MRSA). According to the researchers around Wook Chang, Pseudomonas aeruginosa preferentially colonize the respiratory tract and the gastrointestinal tract. The bacteria, which are resistant to all common antibiotics, can cause dangerous infections, which can be fatal in already weakened persons such as ICU patients, cystic fibrosis and cancer patients, the scientists report. According to the experts threaten wound infections, infections of the respiratory and urinary tract, pneumonia and possibly even blood poisoning or heart disease. Since the Pseudomonas aeruginosa are resistant to most antibiotics, the physicians often have considerable difficulty helping the affected patients, so the statement of the scientists. A new method of treating resistant hospital germs could help save many lives. (Fp)

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Picture: Gerd Altmann