Staph uses nitric oxide enzyme to colonize noses

November 28, 2016

Staph bacteria colonize nasal passages through a newly discovered function for a primeval biochemical mechanism.

The interior of the nose is a prime dwelling place for some forms of staph. More than one-third of the population has a chronic presence of Staphylococcus aureus in their nostrils and sinuses. From there, it can get onto the hands and other skin areas.

Like many bacteria, Staphylococcus aureus makes the enzyme nitric oxide synthase. In other living things that manufacture nitric oxide, the simple molecule controls many complex biological responses. In people, for example, it mediates blood pressure, nerve signals and sexual arousal.

"Much is known about nitric oxide in human physiology," noted Dr. Ferric Fang, professor of laboratory medicine and microbiology at the University of Washington School of Medicine. The UW Medicine researcher added, however, that the effects of nitric oxide production in bacteria have been much less clear.

Fang, along with Traci Kinkel, UW acting instructor of laboratory medicine, and a team of scientists, have been looking at this question. Their most recent findings on the essential role of the enzyme nitric oxide synthase in successful colonization by S. aureus are reported Nov. 28 in Nature Microbiology.

Kinkel explained that S. aureus typically grows into a thick group or biofilm. If the bacteria pack densely into a confined location, eventually most of the available oxygen will be consumed.

This situation can arise when staph tries to take hold and multiply inside the nose. Mucus in the nose also limits the diffusion of oxygen.

As oxygen becomes scarce, Kinkel said, the small amount of nitric oxide produced by the bacteria further restricts aerobic respiration in an effort to reduce oxygen use. This leads to the bacteria transitioning to nitrate consumption, or microaerobic respiration, to maintain energy in the low-oxygen environment.

The researchers outlined the biochemical activities stemming from nitric oxide synthase production. These regulate the transport of electrons in the pathogen's cell membrane, and thereby maintain energy from concentration gradients across the membrane.

"We believe that this elegant mechanism is likely to represent the original, primordial function of enzymatic nitric oxide production in nature," Fang said. The essential bacterial mechanism appears to be evolutionarily conserved in some types of cell receptor signaling in mammals.

Also, the researchers said, in view of the many pathogenic and environmental bacteria that produce the enzyme nitric oxide synthase, and the ubiquity of low-oxygen environments in the natural world, this mechanism is likely to be a widespread bacterial response to limited oxygen.

As a survival method, the mechanism may contribute to the virulence and staying power of the disease-inducing staphylococcus bacteria. It also appears to play a role in resistance to the antibiotic daptomycin, which targets the bacterial cell membrane.

The research results suggest novel strategies for preventing staphylococcal infection by interfering with bacterial nitric oxide synthase.

Seeking alternative staph-fighting approaches is especially important now that serious strains of the bacteria no longer respond readily to strong antibiotics.

"Staphylococcus aureus colonizes an estimated two billion persons worldwide and has become a leading cause of skin, respiratory, and blood stream infections," the researchers wrote. Deaths from methicillin-resistant S. aureus (MRSA) now exceed those caused by Human Immunodeficiency Virus (HIV) in the United States.
The research reported in Nature Microbiology under the title, "An Essential Role for Bacterial Nitric Oxide Synthase in Staphylococcus aureus Electron Transfer and Colonization," was supported by National Institute of Health grants AI44486, AI55396, and AI123124.

University of Washington Health Sciences/UW Medicine

Related Bacteria Articles from Brightsurf:

Siblings can also differ from one another in bacteria
A research team from the University of Tübingen and the German Center for Infection Research (DZIF) is investigating how pathogens influence the immune response of their host with genetic variation.

How bacteria fertilize soya
Soya and clover have their very own fertiliser factories in their roots, where bacteria manufacture ammonium, which is crucial for plant growth.

Bacteria might help other bacteria to tolerate antibiotics better
A new paper by the Dynamical Systems Biology lab at UPF shows that the response by bacteria to antibiotics may depend on other species of bacteria they live with, in such a way that some bacteria may make others more tolerant to antibiotics.

Two-faced bacteria
The gut microbiome, which is a collection of numerous beneficial bacteria species, is key to our overall well-being and good health.

Microcensus in bacteria
Bacillus subtilis can determine proportions of different groups within a mixed population.

Right beneath the skin we all have the same bacteria
In the dermis skin layer, the same bacteria are found across age and gender.

Bacteria must be 'stressed out' to divide
Bacterial cell division is controlled by both enzymatic activity and mechanical forces, which work together to control its timing and location, a new study from EPFL finds.

How bees live with bacteria
More than 90 percent of all bee species are not organized in colonies, but fight their way through life alone.

The bacteria building your baby
Australian researchers have laid to rest a longstanding controversy: is the womb sterile?

Hopping bacteria
Scientists have long known that key models of bacterial movement in real-world conditions are flawed.

Read More: Bacteria News and Bacteria Current Events is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to