A prospective study of intrafamilial transmission and antimicrobial susceptibility of Moraxella catarrhalis

Abstract

Moraxella catarrhalis has been recognized as a particularly threatening respiratory tract pathogen in humans. A prospective study was performed to investigate which strains of M. catarrhalis can be transmitted within families; the study also addressed features of antimicrobial susceptibility. Seventy-five strains were isolated from six participants between July 2002 and February 2004, including 73 that were verified as beta-lactamase-producing strains. Antimicrobial susceptibility was tested for six types of antibiotics and no treatment issues were found. Pulsed-field gel electrophoresis (PFGE) was performed on all strains and 25 independent PFGE patterns were detected. The dominant pattern L (defined in the present study) was found in 21 (28%) of strains that were continuously recovered from children from the same family over an 8-month period. Strains with the patterns G, J, L, M, R, S, U, and W seemed to spread among the children, but there was no evidence of child-parent transmission. In the present study, the characteristics of M. catarrhalis within families have been documented, and PFGE profiles found to reveal alternating colonization and intrafamilial transmission.Key words antimicrobial susceptibility, intrafamilial transmission, Moraxella catarrhalis, pulsed-field gel electrophoresis.Moraxella catarrhalis is a Gram-negative, aerobic, oxidasepositive diplococcus that is frequently detected in the pharynx, especially in the young (1). M. catarrhalis causes sinusitis, bronchitis, pneumonia, and meningitis (2-4). Furthermore, 15-20% of episodes of AOM are caused by this organism, which is recognized as one of the predominant causes of AOM (5-8). M. catarrhalis has also been reported to cause exacerbation of COPD through chronic colonization of the airways (9).Previous studies have shown that M. catarrhalis colonizes the upper respiratory tract of 1-10.4% of adults and 28-100% of infants in the first year of life, (10, 11), which seems to suggest that the prevalence of coloniza- tion is dependent on age. Many studies have characterized M. catarrhalis isolated from children at daycare centers and documented a high prevalence rate and child-to-child transmission routes (12)(13)(14). M. catarrhalis has also been reported to spread among children and their parents or siblings at home (15), which indicates possible ITRs. Furthermore, multi-year longitudinal surveillance has confirmed M. catarrhalis to be a common component of flora during 235 child-months of observation (16). These studies indicate that long-term colonization among children is quite common. Since M. catarrhalis colonization is recognized to be an important risk factor in many infections, such as AOM and exacerbation of COPD, documenting

A Moraxella Virulence Factor Catalyzes an Essential Esterase Reaction of Biotin Biosynthesis

“…It is commonly found in a polymicrobial community with other pathogens such as Streptococcus pneumoniae and Haemophilus influenzae. The vast majority of clinical isolates of M. catarrhalis (>95%) are now resistant to the β-lactamase family of antibiotics that was once considered a front-line treatment for the disease (Masaki et al, 2011). Until now, an efficient vaccine against M. catarrhalis has not yet been developed.…”