Dr. Mikhail Kazachkov MD Director of Pediatric Pulmonology Hassenfeld Children’s Hospital NYU Langone Medical Center

Specific Microbial Signatures Differentiate Chronic Coughs in Children

MedicalResearch.com Interview with:

Dr. Mikhail Kazachkov MD Director of Pediatric Pulmonology Hassenfeld Children’s Hospital NYU Langone Medical Center

Dr. Kazachkov

Dr. Mikhail Kazachkov MD
Director of Pediatric Pulmonology
Hassenfeld Children’s Hospital
NYU Langone Medical Center 

MedicalResearch.com: What is the background for this study? How common is the problem of chronic cough in children?  Is it more common in children with allergies, asthma or reflux?

Response: Chronic cough is one of the leading causes of pediatric referrals to subspecialty physicians.  Its prevalence in the general pediatric population may approach 3% (Galassi et al, Epidemiol. Prev. 2005;29,Suppl.:9–13).

It is important to recognize that the main causes of chronic cough in children are completely different for those in adults.  Specifically, gastroesophageal reflux and postnasal drip are not considered to be important causes of cough in children.  Cough variant asthma, although is a common cause of cough in adults, does not seem to be frequently diagnosed and a cause of chronic cough in children.

The main cause of chronic wet cough in children is protracted bacterial bronchitis (Chang et al, Chest. 2017 Apr;151:884-890).  It is important to recognize that neurologically impaired children have completely different pathogenesis of chronic cough, which is mostly related to aspiration into the lower airway and development of aspiration-related lung disease.

MedicalResearch.com: What are the main findings?

Response: The main findings of our study are related to the diversity of aerodigestive microbiomes and their differences depending on the condition, which causes chronic cough.  We show that there are significant differences in the lower airway microbiomes in children with asthma compared with children with protracted bacterial bronchitis (chronic lower airway infection).  And the airway microbiomes of neurologically impaired children with chronic aspiration into the airway is significantly different from both asthmatics and bacterial bronchitis patients.  We found that the lower airway microbiome in children with asthma is closer in its composition to the microbiome of their upper airway (pharynx).  However, neurologically impaired children with chronic aspiration show very significant difference between their upper and lower airway microbiomes.  We show that increased lower airway secretions and inflammation “change” the lower airway microbiome and make it less similar to the pharyngeal microbiome.

Another important finding of the study is certain microbial “signatures”, which were found in airway and digestive microbiomes and were relatively specific to disease conditions.  E.g. neurologically impaired children with aspiration had high prevalence of the bacteria Veillionella in their airway and digestive microbiomes, Prevotella was found in children with bacterial bronchitis and Granulicatella in asthma.

MedicalResearch.com: What should readers take away from your report?

Response: The main “take home message” here is that DNA sequencing methods of microbiome research allow for much more complete characteristics of the aerodigestive microbial kingdom than conventional culture-based methods in children with chronic cough.

We also would like the readers to recognize the importance of our finding of specific microbial signatures related to certain disease entities.  It is particularly important in neurologically impaired children with suspected aspiration into airway due to the absence of standard methods of diagnostics of this type of aspiration.

We suggest that the finding of certain bacteria in the lower airway could be suggestive of aspiration and even may become the “golden standard of diagnostics” in the future.

MedicalResearch.com: What recommendations do you have for future research as a result of this work?

Response: Future researchers should continue attempting thorough characterization of microbiota of the lower airway in children with different respiratory disease entities.  A lot of work has to be done to link certain microbiome characteristics with the presence and type of lower airway inflammation.

Of course, the researchers have to continue their search for microbial signatures pathognomonic for certain disease processes.
No disclosures 


Pediatr Pulmonol. 2018 Jul 8. doi: 10.1002/ppul.24115. [Epub ahead of print]

Aerodigestive dysbiosis in children with chronic cough.

Kazachkov M1, Kapoor BC1, Malecha PW2, Wu BG3, Li Y3, Levine J4, Erkman J1, Fitzgerald K1, Moy L4, Segal LN3.

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Last Updated on July 29, 2018 by Marie Benz MD FAAD