ASM logoA prior analysis suggested an association between ear infection and obesity. Most ear infections caused by more than one species of bacteria can supposedly be more chronic and antibiotic-resistant. This is because one pathogen seemingly communicates with the other, encouraging it to assist its defenses. Investigators from the Wake Forest University Baptist Medical Center have apparently revealed that interrupting or removing the communication can help cure the infection.

Otitis media (OM) is considered to be among the most common childhood infections. The ailment not only lasts for a long time, but also appears to be antibiotic resistant. The researchers explained that such prolonged and recurrent cases of OM encompass the persistence of the bacteria within a biofilm community. The latter is claimed to be a state in which they are highly resistantant to natural clearance by the immune system as well as to the antibiotic treatment.

W. Edward Swords, an associate professor of microbiology and immunology and senior author of the research remarked, “Interestingly, a recent research found M. catarrhalis to be more frequently associated with polymicrobial OM infections than from single-species OM infections. This suggests that the presence of other bacterial pathogens may impact the persistence of M. catarrhalis or the severity of disease caused by this species.”

During the research, the scientists probably aimed to highlight the communication between bacterial species known to promote bacterial persistence and resistance to antibiotics. These are assumed to be crucial considerations in the diagnosis, preventions and treatment of OM. Claimed to have scrutinized epidemiological data, the researchers affirmed that most of chronic OM infections are polymicrobial in nature. This means that they are probably caused by more than one species of bacteria. Samples of patients with chronic and recurrent OM usually seem to register Haemophilus influenzae and Moraxella catarrhalis together.

Swords commented, “We conclude that H. influenzae promotes M. catarrhalis persistence within polymicrobial infection biofilms via inter-species quorum signaling. AI-2 may therefore represent an ideal target for disruption of chronic polymicrobial infections. Moreover, these results strongly imply that successful vaccination against the unencapsulated H. influenzae strains that cause airway infections may also significantly impact chronic M. catarrhalis disease by removing a reservoir for the AI-2 signal that promotes M. catarrhalis persistence within biofilms.”

The experts ascertained to have analyzed the dynamics between these two bacteria in culture and animal models. The H. influenzae secreted autoinducer-2 (AI-2) that was then supposedly identified as a chemical involved in an interbacterial method of communication which is termed as quorum sensing. This is possibly responsible for the elevation of biofilm formation and antibiotic resistance in M. catarrhalis.

The research is published in mBio, the online open-access journal of the American Society for Microbiology.