A prospective observational study of an epidemic of infection due to Chlamydia pneumoniae strain TWAR in Finnish military trainees provided new information on immunity following infection, the range of clinical syndromes and complications, and cell culture isolation. One-half of the trainees studied (43 of 86) had laboratory evidence of C. pneumoniae infection. The etiologic association of C. pneumoniae with disease was strengthened by the sharp increase in cases of pneumonia and in outpatient visits for acute respiratory disease along with the laboratory evidence of infection. The pattern of serological response suggested that 23 of the trainees had a primary TWAR infection and 20 had a reinfection. Evidence that prior infection modified the illness included the frequency of hospitalization (12 with primary infections vs. 1 with reinfection), the development of pneumonia (10 vs. 0), and the requirement for repeated courses of antibiotic therapy (13 courses vs. 0). Isolation was more frequent in HL cells (n = 25) than in HeLa 229 cells (n = 10).
Animal models are used extensively in the ongoing investigation of a possible causal link between Chlamydia pneumoniae infection and conditions such as asthma and cardiovascular disease. Respiratory infections have been studied in monkeys, while mouse and rabbit models have been used to study both respiratory and cardiovascular infections. The degree of disease induced in mice depends on the strain used, the virulence of the C. pneumoniae strain used, and the dose administered. A characteristic mononuclear pneumonitis occurs, although the infection is systemic and the agent is found outside the lungs, in the circulation, spleen and liver. The infective dose used in the model tends to produce persistent infection, with inflammation continuing after the agent can no longer be cultured from the lungs. In reinfected animals the titre of infective chlamydia in lungs is much diminished, but the inflammation can be quite marked. The continuous persistence of the agent can be demonstrated by polymerase chain reaction (PCR), or, in chronically infected animals, after immunosuppression with cortisone. New Zealand White (NZW) rabbits provide an experimental model, not only for lung infections, but also for C. pneumoniae-induced atherosclerosis. Three laboratories have now reported that after inoculation, plaques develop in the arterial walls of experimental animals on a normal diet. In addition, one laboratory has reported from their studies on atherosclerosis in apoE-deficient and normal mice, that the persistence of the agent in aortic walls could be seen. Further studies are needed to evaluate the effect of the strain of chlamydia and dosage used, the importance of reinfection, the effect of diet and the effect of antibiotic treatment in these models.
BACKGROUND: Sixteen cases of sudden unexpected cardiac death, 15 males and one female, are known to have occurred among young Swedish orienteers from 1979 to 1992, of which seven cases occurred between 1989 and 1992. This is considered to be indicative of an increased death rate. RESULTS: Histopathological evaluation showed myocarditis in a higher than expected proportion of cases. In one such case, which we studied before the sudden unexpected death occurred, the victim had suffered a Chlamydia pneumoniae infection verified by serology, and a nucleotide sequence was found in the heart and lung by means of the polymerase chain reaction (PCR) that hybridized with a probe specific for that organism. Male Swedish orienteers do not, however, seem to have an increased rate of exposure to this agent. No further sudden unexpected deaths among young orienteers have occurred over the past 3.5 years. At the beginning of that period, attempts were made to modify training habits and attitudes.
Comment In: Eur Heart J. 1996 Jun;17(6):810-28781814
BACKGROUND: The cause of age-related degenerative (tricuspid) aortic valve calcification is largely unknown, but one typical characteristic is an active inflammatory process. The presence of Chlamydia pneumoniae in aortic valve stenosis was recently shown. OBJECTIVE: To test the hypothesis that if persistent C. pneumoniae infection plays an active role in the development of aortic stenosis, the organism can be detected in the healthy aortic valves of young persons. DESIGN: A cadaver study. SETTING: Oulu University Hospital, Oulu, Finland. SUBJECTS: 46 consecutive cadavers undergoing autopsy. Measurements: Macroscopic and histologic pathology of aortic valves was determined. The presence of C. pneumoniae was determined by immunohistochemistry. RESULTS: 34 of 46 valves were macroscopically normal. Early lesions of aortic valve disease were found in 12 valves (no lesions in valves from persons 20 to 40 years of age [n = 15], 4 lesions in valves from persons 41 to 60 years of age [n = 16], and 8 lesions in valves from persons older than 60 years of age [n = 15]; P = 0.004). Fifteen of 34 normal valves (44%) and 10 of 12 valves with early lesions (83%) had positive results on staining for C. pneumoniae (P = 0.02). In persons older than 60 years of age, the chance of an early lesion was higher if the valve tested positive for C. pneumoniae (7 of 8 valves with C. pneumoniae infection compared with 1 of 7 valves without C. pneumoniae infection; P = 0.01). CONCLUSIONS: Chlamydia pneumoniae is frequently present in aortic valves and is associated with early lesions of aortic valve stenosis in elderly persons.
The purpose of the study was to find out the frequency of occurrence and the role of Chlamydia infection in the pathogenesis of acquired subglottic stenosis in children. Forty-nine patients of the age from 1 year 10 months to 15 years with acquired cicatricial laryngotracheal stenosis were examined. The immunofluorescent method was used to detect serum antibodies to the antigens of Chlamydia trachomatis and Chlamydia pneumoniae. Dilutions of 1:32 for C. trachomatis and 1:64 for C. pneumoniae were considered positive. The results of the study suggested both a high frequency (26.5%) of Chlamydia infection (C. pneumoniae) of the children with acquired subglottic stenosis, as well as 92% of infected children were either with tracheotomies or had been decannulated earlier. It reasonable to test children with a tracheostomy for the presence of Chlamydia infection to perform timely and specific antibiotic therapy.
To determine the extent and severity of illness and mode of transmission of Chlamydia pneumoniae infection in 3 nursing home outbreaks.
Retrospective cohort study in 3 nursing homes in Ontario from September to November 1994.
A total of 549 residents and 65 staff members.
Morbidity and mortality were determined by a review of disease surveillance forms, residents' charts, and a self-administered questionnaire to staff. Single and paired serum samples for C pneumoniae serological testing and nasopharyngeal swabs for C pneumoniae culture were collected, and direct fluorescent antibody assays were performed to confirm C pneumoniae infection.
The attack rates for confirmed and suspected cases combined were 68%, 46%, and 44% among residents in nursing homes A, B, and C, respectively, and 34% among nursing home C staff. A total of 16 cases of pneumonia confirmed by chest x-ray and 6 deaths were identified. The spectrum of illness among nursing home C residents included a new cough in 58 (100%), fever in 37 (64%), sore throat in 14 (24%), and hoarseness in 8 (14%). Staff members at nursing home C were more likely to report hoarseness (P
BACKGROUND: The epidemiology of Chlamydia pneumoniae in healthy children has not been established. METHODS: This investigation used polymerase chain reaction (PCR) to study the epidemiology of C. pneumoniae in presumed healthy children. Four hundred fifty-three children and 142 personnel at 9 day-care centers were investigated for carriage of C. pneumoniae. Children found to be positive by PCR were also investigated with serology, and their family members were tested with PCR. RESULTS: One hundred and three (22.7%) children had a positive PCR, as had 33 (23.2%) personnel. Fourteen percent of the children younger than 3 years had a positive PCR test compared with 26% of the older children (P
Chlamydia pneumoniae infection is said to be associated with obesity. We studied the association between C. pneumoniae infection and inflammation and increased BMI in 891 Finnish military recruits. IgG seropositivity in arrival and departure serum samples during 6-12 months of military service was considered as persistence of antibodies and a possible indication of chronic infection. Persistently high C-reactive protein (CRP) level (elevated on arrival and departure) (OR 2.2, 95% CI 1.3-3.9), and persistent C. pneumoniae antibodies (OR 2.1, 95% CI 1.5-2.8) were significant risk factors for overweight (BMI 25 kg/m2). In addition, those who had persistent antibodies and persistently elevated CRP levels, or those who had either of them, had a significantly higher BMI (kg/m2) compared to those who had neither of them (25.8 vs. 24.6 vs. 23.5, respectively; P
During the last 5-6 years our understanding of Chlamydia pneumoniae has changed radically. C. pneumoniae is no longer considered a dangerous, obligatory pathogen. Rather, it is a common, highly contagious intracellular opportunist, inducing poor immunity and with a tendency to repeated reinfections. At present, a possible role in the formation of atheromatous plaques is being discussed. There is a significantly higher prevalence of antibodies against C. pneumoniae in coronary heart disease patients than in controls. Another unsolved problem is that of therapy, since chronic lung infection resists long-term macrolide antibiotic treatment. Should additional treatment with cortisone be given? Here we clearly need clinical trials before we move in a totally new direction.
An outbreak of Legionnaires' disease (LD) occurred in Lidköping, Sweden, in August 2004. A cooling tower was identified as the probable source of infection. During the outbreak period an unexpected 3-6-fold increase in pneumonia patients was noted at the local hospital. During 7 weeks LD was diagnosed in 15 patients by urinary antigen and/or sputum culture. Additionally, 15 LD patients were diagnosed later by serology. Patients with LD were generally younger, more healthy, and more often smokers compared to other pneumonia patients. On admittance they had more severe symptoms with high fever and raised CRP levels, and more often hyponatraemia, gastrointestinal and CNS symptoms. A causative agent besides Legionella was found in 2 patients only. A significant titre rise for Mycoplasma and/or Chlamydophila pneumoniae was found in 13 of 29 tested patients with confirmed LD. We conclude that the clinical diagnosis of LD is difficult and that available diagnostic methods detect only a minority of patients in the acute phase. Therefore in severe pneumonia, empirically targeted therapy should be instituted on clinical grounds irrespective of the results of diagnostic tests. The observation of increased antibody levels for M. and C. pneumoniae suggests an unspecific immune reaction and merits further study.