Isolation of Mycoplasma pneumoniae from Children with Lower-Respiratory-Tract Infections

Abstract

The prevalence and clinical pictures of Mycoplasma pneumoniae infections among children were studied using culture and serological techniques. The isolation rate was 22% (195 of 885) in pneumonic patients and 11% (66 of 600) in non-pneumonic patients. In patients three years of age or less, M. pneumoniae was isolated at the same rate from febrile and afebrile cases and from wheezy and non-wheezy cases. In older patients, however, M. pneumoniae was frequently isolated from febrile but non-wheezy cases. A peak in the number of the positive isolates was found in patients who were four years old. The peak number of M. pneumoniae infections at age four was confirmed serologically. This peak was in patients who were younger than those previously reported.

Community outbreak of acute respiratory infection by Mycoplasma pneumoniae

“…Such data contrasts with results published by various authors who point out that first infection in early infancy is usually asymptomatic and that the most affected group is that between five and nine years [1,7,10,[12][13][14]. However, Nagayama et al [15], after studying the cases diagnosed in the pediatric practice of a general hospital in Japan, show that infection occurs very frequently in small children, four being the age with the greatest number of cases registered.…”

Mycoplasma pneumoniae in Korean children: The epidemiology of pneumonia over an 18-year period

“…However, the 1:640 titer, as the single highest antibody titer, is better suited for diagnostic criteria in epidemiological studies than for direct management of individual patients. 13 This study also provided information on reinfection in children after a relatively short interval from the first MP infection. It was previously known that the IgM response may persist for months or years following infection.…”

“…A 4-fold or greater rise in the antibody titers and/or a single titer >1:640 were considered diagnostic of MP infections. 12,13 Antimycoplasma antibody titer was followed up in the following two clinical settings: clinic revisit with new symptoms suggesting respiratory tract infections (20 episodes) and planned sequential follow-up of antimycoplasma antibody titers in the patients without any respiratory symptoms at the time of follow-up (69 episodes), which was part of our previous study. 12 …”

Three familial cases of drug-resistant Mycoplasma pneumoniae infection

“…Instead, it stimulates macrophages via toll-like receptors to release immunomodulatory and inflammatory cytokines and chemokines such as interleukin (IL)-18 and IL-8, which cause excessive immune responses resulting in the formation of pneumonia [13,14,25,26,29]. This immunopathogenesis of pneumonia must be age dependent because it has been reported that children younger than 3 years of age less frequently develop pneumonia than older children when infected by this organism [12,21]. This holds true in this series of patients; that is, the oldest patient had the most severe disease and the youngest patient had the mildest disease.…”