Results of Molecular Detection ofMycoplasma pneumoniaeamong Patients with Acute Respiratory Infection and in Their Household Contacts Reveals Children as Human Reservoirs

Abstract

During a 30-month prospective study in The Netherlands, the distribution of Mycoplasma pneumoniae and respiratory viruses among 1172 patients with acute respiratory infection (ARI) who were treated in the outpatient general practitioner setting was studied. M. pneumoniae, as detected by polymerase chain reaction analysis, was present in 39 (3.3%) patients. The infection rate was similar in all age groups. Nose and throat samples collected from 79 household contacts of M. pneumoniae-positive index patients revealed M. pneumoniae in 12 (15%) cases. The frequency of M. pneumoniae among household contacts of index patients treated with appropriate antibiotics and untreated index patients was similar. Nine of the 12 M. pneumoniae-positive household contacts were <16 years old (P=.02), and 4 (44%) of them did not develop ARI. Apparently, children are a relevant reservoir for M. pneumoniae.

Mycoplasma pneumoniaeand Its Role as a Human Pathogen

“…The usual explanation for such persistence has been that the organism attaches strongly to and invades epithelial cells and that macrolide or tetracycline antibiotics commonly used for treating mycoplasmal infections are bacteriostatic and unable to kill all of the organisms. Surveillance studies using culture and/or PCR indicate that a prolonged asymptomatic carrier state may occur in some persons, providing a reservoir for spread of the organism to others (109,143,162,254). Gnarpe et al (162) demonstrated that 13.5% of 758 healthy volunteers harbored the organism.…”

“…Since the organisms tend to be associated with desquamated cells, relatively large droplets may be required for transmission, as evidenced by the close personal contact typical of outbreak settings, e.g., schools, military barracks, and institutions. M. pneumoniae infections commonly spread gradually among family members within a household (109,137,403). In view of the intimate contact needed for droplet transmission and the slow (6-h) generation time of M. pneumoniae, 1 to 3 weeks of incubation for each case is typical, and several cycles may be necessary before intrafamily transmission is complete.…”

“…Foy et al (145) reported that 39% of family contacts may eventually become infected with M. pneumoniae, many asymptomatically. DorigoZetsma et al (109) found that among 79 asymptomatic household contacts of 30 index cases with acute respiratory tract infection due to M. pneumoniae, 15% harbored the organism, with a significantly greater number being children under 15 years of age. A novel mathematical model for investigating the control and spread of disease transmission has recently been applied to assess the effects of interventions in outbreaks of M. pneumoniae in closed communities (288).…”

“…M. pneumoniae may also be present in the respiratory tract concomitantly with other pathogens (47,109,137,180,182,252,446), and there is some evidence from humans and animal models indicating that infection with M. pneumoniae may precede and somehow intensify subsequent infections with various respiratory viruses and bacteria, including S. pyogenes and Neisseria meningitidis (78). Potential explanations for such a synergistic effect include immunosuppression or alteration in respiratory tract flora due to the presence of M. pneumoniae (78,255,269,358).…”

Evaluation of 12 Commercial Tests and the Complement Fixation Test for Mycoplasma pneumoniae -Specific Immunoglobulin G (IgG) and IgM Antibodies, with PCR Used as the “Gold Standard”

“…In 5 to 10% of patients with M. pneumoniae infection, especially young adults, the infection may cause atypical pneumonia (17). Reinfections with M. pneumoniae do occur, but it is unclear whether persistent carriage of mycoplasmas in an immune subject occurs (5,8,13). As M. pneumoniae lacks a cell wall, the commonly described ␤-lactam antibiotics are not effective and adequate laboratory diagnosis is important.…”