2014 Volume 2 Issue 2 Pages 83-86
We studied changes in antimicrobial susceptibilities of Haemophilus influenzae isolated from the nasopharynx of pediatric patients treated at Nemuro Municipal Hospital between 2008 and 2013. A rapid increase in β-lactamase producing strains of H. influenzae, such as BLPAR and BLPACR, was observed from 0.3–2.3% between 2008 and 2011 to 30.4% in 2012 and 33.5% in 2013. A rapid decrease in BLNAR strains
was also observed from 55.3–59.8% between 2008 and 2011 to 25.4% in 2012 and 11.9% in 2013. The most important difference between BLNAR and BLPAR in the management of pediatric acute otitis media (AOM) is the susceptibility to amoxicillin/clavulanate (CVA/AMPC). CVA/AMPC is more appropriate as the first-line antibacterial agent in this environment where BLPAR is the dominant drug-resistant strain of H. influenzae.
Although it is difficult to distinguish H. influenzae from non-haemolytic H. haemolyticus by standard microbiological methods, we determined that these susceptibility changes are those of true H. influenzae, not of H. haemolyticus, since a similar susceptibility pattern was also seen in the isolates obtained from the middle ear effusions of AOM.
