Bacteria are everywhere. Literally… everywhere, both around us and in us. Is it bad? Not really, as there are many different types of bacteria in our body that help us with various bodily processes. Most of those around us are not harmful in any manner and even if we come across a pathogen, our immune system is capable of fighting it off. However, every once in a while, a harmless bacteria undergoes certain changes and takes us by surprise. This is exactly what happened in the case of Elizabethkingia anophelis.
Identified as a separate species in 2011, not much was known about E. anophelis. It was found in the gut of a mosquito by a Swedish researcher by the name of Ingrid Faye and was named after the mosquito itself (Anopheles gambiae). After being identified, the bacteria were identified in Bangui (Central African Republic), Singapore and Hong Kong, but it was not until 2015 that the bacteria grabbed the attention of scientists around the world. The state of Wisconsin had a sudden outbreak in November 2015, and it ended up claiming 18 lives. E. anophelis had never caused such a situation before and what shocked researchers is that this outbreak happened in winter, when there are no or very few mosquitoes in Wisconsin. So what changed in the bacteria that allowed it to affect so many people?
What is Elizabethkingia anophelis?
E. anophelis is a yellow rod-shaped bacterium. It is a major bacteria in the gut system of Anopheles gambiae. As mentioned above, it was reported as being infectious in Bangui and Singapore. In both those cases, it was said to be resistant to multiple drugs. Multi-drug resistance indicates that a number of antibiotics do not affect or treat the bacteria.
What problems can it cause?
E. anophelis is a smart pathogen and it mostly affects elderly people. The bacteria is particularly likely to attack people with underlying health issues. The targets are immune-compromised, which makes it easy for the bacteria to multiply freely in the body. The bacterium is known to cause meningitis, respiratory tract illness and septicemia. Septicemia, also known as bacteremia, is a serious bloodstream infection. The symptoms include fever, shortness of breath, chills, and cellulitis.
What changed before the Wisconsin outbreak?
Before Wisconsin, this bacteria was not known for widespread infections. The cases used to be isolated ones and had never turned into an outbreak. So what went wrong for the bacteria to act in such an unusual manner?
The isolates obtained from the Wisconsin patients were mutating and evolving at an increased rate. The probable cause for this was identified as a disruption of the mutY gene coding for adenine glycosylase. One of the strains also disrupted the mutS gene, which encodes a protein for nucleotide-binding. Both MutY and MutS genes work together to avoid mistakes in the newly synthesized DNA strand.
More mutations that are beneficial were also observed in these strains. Genes coding for polysaccharide utilization and capsule secretion were disrupted. It made them speculate that these mutations helped the bacteria reduce the binding to immune bodies and increase adhesion to other surfaces. The combination of such changes helped them to replicate and spread at a much greater rate than had previously been seen.
What is the treatment?
As the E. anophelis is resistant to multiple drugs, few options are left. Recent studies have shown that drugs like fluoroquinolones, minocycline, rifampin, and trimethoprim/sulfamethoxazole have an effect on the bacteria. Most of the time, a combined drug therapy is used for effective treatment.
The case of E. anophelis is puzzling, as it suddenly caused an outbreak and just as suddenly disappeared. The source for the particular strain was never identified leaving a big question mark on what exactly caused those mutations. Because the source’s environment would have given us clues on what might have changed the E. anophelis.
Nevertheless, it was a reminder that we still know very little about the bacteria we study and more research is required to be better prepared to act against it. It also shows the need to maintain constant surveillance of pathogens and keep our eyes open for any sign of resurgence.
- American Society for Microbiology
- MicrobeWiki – Kenyon College
- National Center for Biotechnology Information (NCBI)