Intermittent azithromycin treatment for respiratory symptoms in patients with chronic chlamydia pneumoniae infection

Chlamydia pneumoniae (Cpn) is a common respiratory pathogen with a biphasic replicative cycle and has a tendency to cause chronic infections. Azithromycin is commonly used for the treatment of Cpn infections, but little is known about the optimal dose and duration of therapy. In this prospective double-blind, randomized study the effects of azithromycin and placebo were compared regarding longstanding airway and/or pharyngeal symptoms in patients with chronic Cpn infection. Further, effects on antibody titres and lung function were assessed. 103 patients were treated with either azithromycin 500 mg daily for 5 d, repeated 3 times with a 23-d interval, or placebo. Patients were examined 4 months and 1 y after completed treatment. Evaluation of symptoms showed general improvement and less hawking in patients treated with azithromycin compared to placebo after 4 months, but there was no sustained difference 1 y after completed treatment. The antibody titres remained stable, and there was no influence on lung function. Adverse events, primarily gastrointestinal, were more frequently reported with azithromycin than placebo. In conclusion, azithromycin was effective for reduction of respiratory symptoms in patients with chronic Cpn infection, but prolonged intermittent treatment with high doses did not eradicate the chronic infection.

No prognostic significance of chronic infection with Chlamydia pneumoniae in acute coronary syndromes: insights from the Global Utilization of Strategies to Open Occluded Arteries IV Acute Coronary Syndromes trial

BACKGROUND

Although relationships between chronic Chlamydia pneumoniae (Cpn) infection and the risk of coronary events in stable coronary artery disease patients have been reported, a similar link in acute coronary syndrome (ACS) patients has not been consistently observed.

METHODS

In a nested case-control substudy of the Global Utilization of Strategies to Open Occluded Arteries IV Acute Coronary Syndromes trial, 295 cases (30-day death/myocardial infarction [MI]) were matched by age, sex, baseline creatine kinase-myocardial kinase, and smoking status with 295 control subjects. To test the hypothesis on 1-year mortality, another subset (n = 276) was drawn from the 590-patient cohort; 138 patients who died at 1 year plus the matching controls who survived at 1 year. We measured Cpn IgG and IgA antibody titers in baseline serum with microimmunofluorescence. Conditional logistic regression was used to quantify the prognostic relevance seropositivity (IgG > or = 1:32; IgA > or = 1:16) and elevated titer levels.

RESULTS

The prevalence of Cpn IgG and IgA was similar between cases and controls (30-day death/MI: IgG, 80% vs 85%, P = .126; IgA, 45% vs 37%, P = .079), and were not statistically significant predictors of 30-day death/MI after baseline adjustment. Likewise, the 1-year death cohort had comparable proportions of Cpn IgG and IgA among cases and controls (86% vs 91% [P = .265] and 49% vs 43% [P = .334], respectively), and did not add prognostic value.

CONCLUSIONS

These findings are in concert with study results suggesting that chronic Cpn infection is not associated with 30-day death/MI or 1-year mortality in non-ST elevation ACS.

Detection of Chlamydia pneumoniae on cytospin preparations from bronchoalveolar lavage in COPD patients and in lung tissue from advanced emphysema

Chronic obstructive pulmonary disease (COPD) is associated with smoking but other etiological factors contribute. Chlamydia pneumoniae is an obligate intracellular bacterium causing both acute and chronic respiratory tract infections. Studies have revealed an association between chronic C. pneumoniae infection and COPD, asthma and lung cancer but there have been difficulties detecting C. pneumoniae in the bronchial tree. Cytospin slides prepared from bronchoalveolar lavage (BAL) fluid from 14 patients with COPD, 10 healthy smokers (S) and 7 non smokers (NS) were analyzed with a fluorescein isothiocyanate labeled monoclonal antibody to C. pneumoniae. Lung tissue from 24 patients with advanced emphysema who had undergone lung volume reduction surgery (LVRS) was examined with immunohistochemistry for C. pneumoniae. Archived serum samples for detection of specific C. pneumoniae antibodies by microimmunofluorescence were available for 30 of the BAL subjects and 11 of LVRS patients. C. pneumoniae elementary body like structures were found in 29% of cytospin specimens from COPD patients, 14% of NS and 10% of HS. C. pneumoniae was detected in lung tissue in 8%. COPD patients had higher titres of IgG and IgA than NS and S. There was no association between occurrence of C. pneumoniae in BAL fluid and antibody titres. In conclusion, the assays used for detection of C. pneumoniae in lung tissue are feasible, and could be adapted in adequately powered studies to further confirm an association between C. pneumoniae infection and COPD.

Association between Chlamydia pneumoniae antibodies and wheezing in young children and the influence of sex

BACKGROUND

The proposed association between Chlamydia pneumoniae (Cpn) infection and wheezing needs further clarification.

METHODS

Serum samples obtained from 1581 children aged 4 years in a population based cohort were tested for antibodies to Cpn and IgE antibodies to common allergens. Data on environmental factors and disease were collected prospectively from birth.

RESULTS

The occurrence of IgG antibodies to Cpn at 4 years of age was associated with reported wheezing at different ages; however, these findings were most often not significant. In girls, the occurrence of anti-Cpn IgG was associated with wheezing at the ages of 1, 2, and 4 years (odds ratios (ORs) 3.41 (95% confidence interval (CI) 1.46 to 7.96), 2.13 (95% CI 1.02 to 4.44), and 2.01 (95% CI 1.14 to 3.54), respectively), and even higher ORs were observed for each age category when only high level antibody responses to Cpn were analysed. At the time of blood sampling the association between anti-Cpn IgG and wheezing was restricted to girls without atopic sensitisation (OR 2.39 (95% CI 1.25 to 4.57). No associations with wheezing were detected in boys, in whom IgE sensitisation was inversely associated with the presence of anti-Cpn IgG (OR 0.49 (95% CI 0.26 to 0.90)).

CONCLUSIONS

This study suggests an association between evidence of earlier Cpn infection and a history of wheezing in young girls. Infection with Cpn may be an important risk factor for wheezing and possibly for non-atopic asthma, predominantly in girls.

Chlamydia pneumoniae infection predicts a reduced risk for subsequent atopic disease

AIM

To investigate long-term effects on children previously infected with Chlamydia pneumoniae.

METHODS

A follow-up questionnaire was sent to all participants from a former population-based study in order to investigate health status during the 4 y that had elapsed between the two studies. In the original study, the prevalence of C. pneumoniae infection was 23% as determined by PCR analyses on throat swab specimens. These PCR results were found to have no detectable correlation for clinical disease. The main outcome measures in this follow-up study were the reported prevalence of respiratory tract infections, asthma and allergy.

RESULTS

Approximately 83% completed the follow-up questionnaire. No increase in respiratory tract infections was reported by children previously found to have C. pneumoniae infection. A diagnosis of allergy was more common in the former PCR-negative population (13.4% vs 4.7%, p<0.03). The differences were most apparent in the population with atopic heredity. In a logistic regression model with different suggested risk factors for allergy, earlier infection with C. pneumoniae reduced the risk for allergy (OR=0.13; 95% CI: 0.02-0.99). This was not found for asthma.

CONCLUSION

A positive PCR test for C. pneumoniae in young children was associated with a lower risk of developing allergic airway disease in this study population, and did not predict an increase in respiratory tract infections.

Chronic Chlamydia pneumoniae infection is a risk factor for the development of COPD

Smoking is the major risk factor for the development of Chronic Obstructive Pulmonary Disease (COPD), but epidemiological data suggest that other etiological factors may also be involved. Chlamydia pneumoniae (Cpn) is an established cause of acute and chronic upper and lower respiratory tract infections. Data obtained from in vitro and in vivo studies indicate that Cpn infection can be involved in the development of both small airways disease and emphysema, the two major components of COPD. The aim of this study was to investigate the possible association between chronic Cpn infection and COPD. The study population was comprised of 199 consecutive patients who underwent bronchoscopy due to longstanding airway symptoms and for whom spirometry and serum samples for serology were available. Acute and convalescent sera were analysed for specific IgG and IgA Cpn antibodies using microimmunofluorescence. Chronic Cpn infection, defined as persistent elevated titres of IgA > or = 1/64, was present in 85 patients. Chronic infection was associated with smoking and higher age, but no gender difference was observed. Thirty patients had COPD, defined as FEV1/FVC < 70% without any features of asthma. Patients with COPD were older than those without, and there was no association with gender in this group. A statistically significant association, remaining after correction for smoking, was observed between chronic Cpn infection and COPD, and there was a trend for decreasing lung function with increasing antibody titres. The results suggest that chronic Cpn infection may be an independent risk factor for the development of COPD.

A Randomized, Controlled Trial of Doxycycline and Rifampin for Patients with Alzheimer's Disease

OBJECTIVES

To assess whether doxycycline and rifampin have a therapeutic role in patients with Alzheimer's disease (AD).

DESIGN

Randomized, triple-blind, controlled trial.

SETTING

Three tertiary care and two community geriatric clinics in Canada.

PARTICIPANTS

One hundred one patients with probable AD and mild to moderate dementia.

INTERVENTION

Oral daily doses of doxycycline 200 mg and rifampin 300 mg for 3 months.

MEASUREMENTS

The primary outcome was a change in Standardized Alzheimer's Disease Assessment Scale cognitive subscale (SADAScog) at 6 months. Secondary outcomes were changes in the SADAScog at 12 months and tests of dysfunctional behavior, depression, and functional status.

RESULTS

There was significantly less decline in the SADAScog score at 6 months in the antibiotic group than in the placebo group, (-2.75 points, 95% confidence interval (CI)=-5.28 to -0.22, P=.034). At 12 months, the difference between groups in the SADAScog was -4.31 points (95% CI=-9.17-0.56, P=.079). The antibiotic group showed significantly less dysfunctional behavior at 3 months. There was no significant difference in adverse events between groups (P=.34). There were no differences in Chlamydia pneumoniae detection using polymerase chain reaction or antibodies (immunoglobulin (Ig)G or IgA) between groups.

CONCLUSION

Therapy with doxycycline and rifampin may have a therapeutic role in patients with mild to moderate AD. The mechanism is unlikely to be due to their effect on C. pneumoniae. More research is needed to investigate these agents.

Azithromycin therapy in patients with chronic Chlamydia pneumoniae infection and coronary heart disease: immediate and long-term effects on inflammation, coagulation, and lipid status in a double-blind, placebo-controlled study

Background: An association between Chlamydia pneumoniae (Cp) infection and coronary heart disease (CHD) has already been reported. We investigated the relationship between Cp infection and other risk factors in CHD patients, as well as the effects of azithromycin treatment. Methods: We studied 38 patients with Cp infection (Cp-pos) and 15 without (Cp-neg). Cp-pos patients had, both at inclusion and 2 years prior to inclusion, elevated Cp-specific IgA-antibodies, with or without the presence of pharyngeal Cp by polymerase chain reaction (PCR) detection. Blood was analyzed for Cp-antibodies, interleukin-6, interleukin-1 receptor antagonist (IL-1ra), CRP, orosomucoid, fibrinogen, leukocytes, PAI-1, tPA, von Willebrand factor (vWf), platelet count and aggregation, and lipids. Cp-pos patients were randomized to placebo or oral azithromycin, 500 mg on day 1 and then 250 mg/day for 4 days, with repeated therapy after 3 weeks. Blood was taken immediately, as well as 3 months and 2 years after therapy. Results: CRP and IL-1ra levels were higher in Cp-pos than in Cp-neg patients: median, interquartile range 8.5 (3.0-20) vs. 2.0 (1.0-3.8) mg/l, and 316 (165-404) vs. 178 (118-195) ng/l, p=0.0006 and p=0.002, and platelet aggregation was lower: 4.8 (2.9-6.4) vs. 8.1 (4.7-11.4) Omega, p<0.05. tPA levels increased in azithromycin-treated patients between entry and 3-month follow-up: mean+/-S.D. 3.7+/-4.2 vs. 1.0+/-2.1 microg/l, p<0.05. Other variables did not differ. Conclusions: Cp infection was associated with increased inflammatory activity and lower platelet aggregability, suggesting that inflammation may be of greater pathophysiological importance than platelet activity in these patients. Although an effect on Cp infection was not shown, azithromycin may have a positive effect on fibrinolysis, as increased levels of tPA were observed in the treatment group.

A family with abdominal aortic aneurysms

This investigation focused on 7 siblings to 2 brothers with abdominal aortic aneurysm (AAA), with respect to AAA, Chlamydia pneumoniae (CP) serology, serum cholesterol, and smoking habits. Five male and 4 female siblings were included. All siblings underwent ultrasonography, and surgical specimens from the aorta were prepared for immunohistochemical (IHC) analysis. Blood was obtained from all living siblings and serum cholesterol level was analyzed. Serologic analysis was done by microimmunofluorescence (MIF). Smoking habits were recorded. In addition to the 2 known siblings with AAA, 2 other brothers with AAA were found. Four of 8 siblings had IgG 1/512 or greater and 7 of 8 had IgA 1/64 or greater. Two of 3 were positive for CP in IHC obtained from aortic specimens. Two of 8 had hypercholesterolemia; 7 of 9 were smokers. C. pneumoniae as well as smoking seems to be important in the pathogenesis of AAA in this small cohort; however, larger patient cohorts are needed.

Multiple infections and subsequent cardiovascular events in the Heart Outcomes Prevention Evaluation (HOPE) Study

BACKGROUND

Limited prospective epidemiological data are available on the relation between exposure to Chlamydia pneumoniae, Helicobacter pylori, cytomegalovirus (CMV), and hepatitis A virus (HAV), individually or as a total pathogen score, and human cardiovascular (CV) disease.

METHODS AND RESULTS

We analyzed enrollment sera from 3168 Canadian patients in the Heart Outcomes Prevention Evaluation (HOPE) study for antibodies to C pneumoniae, H pylori, CMV, and HAV and measured the relation between serostatus and 494 adjudicated trial outcomes of myocardial infarction, stroke, or CV death over 4.5 years of follow-up. CV events were associated with CMV serostatus (covariate-adjusted hazard ratio [HR], 1.24; 95% CI, 1.01, 1.53). Neither C pneumoniae IgG (adjusted HR, 0.87; 95% CI, 0.68, 1.10), C pneumonia IgA (adjusted HR, 1.10; 95% CI, 0.90, 1.34), H pylori IgG (HR, 0.99; 95% CI, 0.82, 1.19), nor HAV IgG (HR, 1.01; 95% CI, 0.83, 1.24) predicted CV events. Total pathogen score was associated with CV events (adjusted HR for 4 versus 1 or 0=1.41; 95% CI, 1.02, 1.96).

CONCLUSIONS

Exposure to CMV but not to C pneumoniae, H pylori, or HAV was associated with a slight excess risk of subsequent myocardial infarction, stroke, or CV death in HOPE study patients, and total pathogen score based on these infections predicted a small increased hazard of CV events.

Does chronic Chlamydia pneumoniae infection increase the risk of myocardial injury? Insights from patients with non-ST-elevation acute coronary syndromes

BACKGROUND

Cumulative evidence suggests a positive association between Chlamydia pneumoniae (Cpn) infection and risk of future coronary events among patients with stable coronary artery disease. However, its prognostic role in unstable coronary syndromes is less well defined. Because Cpn immunoglobulin A (IgA) may be a more reliable indicator of chronic infection than immunoglobulin G (IgG), we speculated that in patients with non-ST-elevation acute coronary syndromes (ACS), this marker might serve as a more useful prognostic tool. Accordingly, we evaluated plasma samples acquired at presentation in 178 patients with ACS for a possible association between Cpn IgA titer and biochemical evidence of myocardial injury.

METHODS

Cpn IgG (positive if > or =1:32), and IgA titers (positive if > or =1:16) were measured by use of the microimmunofluorescence technique in 70 patients with ACS in whom myocardial injury developed associated with their presenting events (elevated CK-MB and/or troponin I); and in 108 patients with ACS without such injury. The odds ratios (ORs) for myocardial injury associated with consecutive antibody titers were determined for each of Cpn IgG and IgA. Multiple logistic regression was applied to adjust for key baseline characteristics.

RESULTS

Median age of subjects was 64 years; 63% were male and 33% were smokers. The median antibody titers among those with and without myocardial injury respectively were as follows: IgG (1:128 vs 1:128), IgA (1:32 vs <1:16, P =.2). The adjusted ORs for myocardial injury associated with consecutive IgA titers were as follows: IgA > or =1:16, adjusted OR 1.49 (P =.22); > or =1:32, OR 1.95 (P =.04); > or =1:64, OR 1.37 (P =.38); > or =1:128, OR 0.77 (P =.55). No significant trend was found for any IgG titer.

CONCLUSIONS

Among patients with non-ST-elevation ACS, a Cpn IgA > or =1:32 at presentation was associated with a significantly higher risk of myocardial injury complicating the presenting event.

Relationship of anti-60 kDa heat shock protein and anti-cholesterol antibodies to cardiovascular events

BACKGROUND

Several recent studies have indicated an association between key inflammatory mediators and atherosclerotic diseases. We evaluated whether high levels of antibodies against heat shock proteins and cholesterol (ACHA) predicted cardiovascular (CV) events.

METHODS AND RESULTS

We used blood samples from the Heart Outcomes Prevention Evaluation (HOPE) study to conduct a nested case-control study of 386 cases with CV events and 386 age- and sex-matched HOPE study controls without events. We explored the relationship between anti-hsp antibodies, ACHA, and subsequent outcomes (incident myocardial infarction, stroke, or CV death) during a mean follow-up of 4.5 years using conditional logistic regression. High levels of anti-hsp65 antibodies (> or =90th percentile) predicted CV events (OR, 2.1; 95% CI, 1.2 to 3.9, P=0.01). Anti-hsp60 antibodies did not predict any event type, whereas incident stroke developed significantly less frequently in patients with high ACHA levels. Anti-hsp antibodies and ACHA did not correlate with inflammatory (fibrinogen, C-reactive protein, interleukin-6, intracellular adhesion molecule-1) or infectious markers (C pneumoniae or cytomegalovirus antibodies). Anti-hsp65 antibodies (> or =90th percentile) and fibrinogen (highest tertile) had a strong joint effect: patients with high concentrations of both had more CV events (OR, 5.5; 95% CI, 1.8 to 17.5, P=0.004) than patients with low levels of both. A similar joint effect (OR, 2.7; 95% CI, 1.3 to 5.7, P=0.01) was found for high levels of anti-hsp65 and presence of cytomegalovirus antibodies.

CONCLUSIONS

Serum antibodies to hsp65 were associated with subsequent CV events in this study of high-risk patients, independent of conventional cardiovascular risk factors and other inflammatory markers.

Comparison of individuals with and without specific IgA antibodies to Chlamydia pneumoniae: respiratory morbidity and the metabolic syndrome

STUDY OBJECTIVES

To determine whether a correlation exists between markers for persistent Chlamydia pneumoniae infection, respiratory morbidity, and the metabolic syndrome.

DESIGN

Case-control study. A group of individuals with serologic markers (specific IgA > or = 1/128) suggestive of persistent C pneumoniae infection were compared with a group of control subjects without IgA antibodies (< 1/32).

SETTING

Apoteksgårdens Health Care Center, Kopparberg, Sweden.

PARTICIPANTS

One hundred case subjects (61 men and 39 women) and 100 control subjects matched for age and gender (mean age, 55 years).

MEASUREMENTS AND RESULTS

Individuals completed a questionnaire on respiratory symptoms and smoking habits. Body mass index (BMI) was calculated, BP, and peak expiratory flow (PEF) were determined. Blood specimens were drawn for determination of high-sensitivity C-reactive protein (hsCRP), blood glucose level, serum lipids, and Chlamydia antibodies. No significant difference was found between case subjects and control subjects regarding myocardial infarctions, stroke, diabetes type II, BP, BMI, hsCRP, blood glucose levels, and serum lipids. Symptoms of both asthma and chronic bronchitis were more common in case subjects, as were symptoms of chronic upper respiratory tract infections (p < 0.005). Case subjects with asthma or chronic bronchitis had more chronic upper respiratory tract disorders (p < 0.05). Symptoms of chronic respiratory tract diseases increased parallel to increasing specific C pneumoniae IgA antibody titers (p < 0.0005). PEF percentage of the predictive value was inversely correlated (p < 0.0005) to IgA antibody titers.

CONCLUSION

The data show that persistent increased levels of C pneumoniae IgA antibodies were associated with pronounced respiratory dysfunction. These data provide additional evidence suggesting that IgA antibodies may be a marker for persistent C pneumoniae infection.

Antibodies to Chlamydia pneumoniae in young Swedish orienteers

During 1992-93 sera from 1790 Swedish elite orienteers were tested for antibodies to Chlamydia pneumoniae. The reason for this was that a cluster of 16 cases of sudden unexpected cardiac death had occurred among Swedish orienteers and DNA from C. pneumoniae had been found in the myocarditic heart and in the lung in 1 of 2 deceased athletes in whom testing was feasible; in addition, C. pneumoniae IgG was found in all 5 cases where serum was available. Among the orienteers, the prevalence rates of IgG antibodies in males and females were 54% (n = 1194) and 50% (n = 596), respectively. The corresponding figures for 319 male and female blood donors were 60% (n = 169) and 53% (n = 150), respectively. These differences are not statistically significant. Male orienteers had a lower prevalence of IgA antibodies than male blood donors (19% and 26%, respectively; p < 0.05), while no such difference was found in females (16% and 18%). The prevalence of IgM antibodies was < 1% in all groups. Neither the performance level of the orienteers nor the place of residence affected the antibody prevalence. In conclusion, Swedish orienteers do not show a higher prevalence of antibodies to C. pneumoniae than healthy blood donors.

An association between chronic infection with Chlamydia pneumoniae and lung cancer. A prospective 2-year study

This study assesses a possible relationship between chronic Chlamydia pneumoniae (Cpn) infection and lung cancer (LC). A total of 210 consecutive patients (136 M, 74 F) were diagnosed with LC during a 2-year period. Blood was obtained from 128 M and 70 F patients for Cpn serology. Repeat blood specimens were taken after 3 months. Throat specimens for Cpn DNA analysis by PCR were taken from 110/136 M and 63/74 F Seventy-four cytobrush specimens were taken and also analyzed by polymerase chain reaction (PCR). Fifty (29 M, 21 F) bronchial biopsies and 8 (6 M, 2 F) tumors resected at surgery were analyzed for Cpn by immunohistochemistry (IHC). Males had significantly more often squamous-cell carcinoma (SCC) than females. Other types of LC were more equally distributed between males and females. The difference between males and females regarding smoking history was significant, and male LC patients had significantly higher levels of IgG and/or IgA antibodies than female LC patients. Male and female LC patients had significantly higher prevalences of high antibody titers than controls. A high prevalence of unusually high titers of specific Cpn antibodies was found in male LC patients. This could indicate that LC may be induced by chronic Cpn infection, since stable high titers of Cpn antibodies, especially IgA, are a hallmark of chronic infections.

Demonstration of Chlamydia pneumoniae in the adenoid from children with and without secretory otitis media using immunohistochemistry and PCR

Chlamydia pneumoniae has been found in patients with middle ear inflammation. The adenoid, which has a central role in the development of secretory otitis media (SOM), may act as a reservoir for bacteria causing ear infection. Adenoid tissue was examined for the presence of C. pneumoniae. Twenty children undergoing adenoidectomy because of hyperplastic adenoids, 10 with SOM and 10 without SOM, were examined with nasopharyngeal swabs for routine bacteriological culture, serology for C. pneumoniae and throat swabs for C. pneumoniae PCR. The removed tissues were analyzed for C. pneumoniae using immunohistochemical (IHC) analysis and PCR. In the group of children with SOM samples were also taken from the middle ear fluid for routine bacteriological culture and PCR for C. pneumoniae. C. pneumoniae was found in the adenoid by PCR in 3 cases from each group and from all 20 children by IHC. Four children in each group had increased levels of specific antibodies to C. pneumoniae. Two children with SOM had high antibody titers and a positive PCR from a throat swab. Two children were PCR-positive for C. pneumoniae in fluid from the middle ear. The significance of these findings is not yet clear.

Chlamydia pneumoniae in children undergoing adenoidectomy

Chlamydia pneumoniae is a common respiratory pathogen which is often found in paediatric populations. Little is known about the true colonization rate and the localization of the bacteria in the respiratory tract. In this study, immunohistochemistry was used to examine adenoids from 69 children undergoing elective adenoidectomy. Throat swabs for polymerase chain reaction (PCR) and blood samples for serology were also obtained. Chlamydia pneumoniae was demonstrated in the adenoids by immunohistochemistry in 68 of the children. Five children (7%) had a positive C. pneumoniae PCR test from throat swabs and 14 children (20%) had detectable antibodies by the microimmunofluorescence technique.

CONCLUSION

The results suggest that C. pneumoniae is a common finding in the adenoids of children undergoing adenoidectomy. Whether or not C. pneumoniae plays a pathogenic role in this patient population could not be determined from the data obtained in this investigation.

Comparison of a new commercial EIA kit and the microimmunofluorescence technique for the determination of IgG and IgA antibodies to Chlamydia pneumoniae

Chlamydia pneumoniae infection is often diagnosed by analyzing specific antibodies to C. pneumoniae in sera. The method which has been used as the reference method, or "gold standard", the microimmunofluorescence test (MIF), demands a high level of experience for proper interpretation. A number of commercial enzyme immunoassay (EIA) tests have been introduced to the market in the past few years. These provide objective reading of titers, but are genus specific and not species specific. The latest EIA introduced, LabSystems EIA for C. pneumoniae, was investigated using several groups of clinically relevant patient sera in a comparison with MIF. It was found that the LabSystems EIA did not discriminate between antibodies to C. trachomatis and C. pneumoniae when tested with sera containing high titers of C. trachomatis antibodies. The correlation between C. pneumoniae EIA and MIF IgG and IgA titers was, however, good in the patient groups not having a high background of C. trachomatis antibodies: hypertensives, n= 199 and patients with chronic C. pneumoniae infections and ischaemic heart disease, n=33. In conclusion, the LabSystems EIA is a method which can be useful for screening populations with low prevalences of C. trachomatis/C. psittaci infection for antibodies to C. pneumoniae. It cannot replace the MIF test due to the lack of discrimination between different chlamydial antibody types.

Seroprevalence of antibodies to Chlamydia pneumoniae in elderly people: a two-decade longitudinal and cohort difference study

A gerontological population of 178 men and 249 women was investigated regarding the prevalence of antibodies specific to Chlamydia pneumoniae. A longitudinal substudy was carried out on 22 men and 44 women, age range 70-90 y. Antibodies specific to C. pneumoniae were common. Men had higher prevalences and higher antibody levels than women. More than half of the individuals in the longitudinal study had significant IgG and/or IgA titre changes (> or = 4-fold) between the ages of 70 and 90 y, suggesting that C. pneumoniae infections are common in the elderly population. This is of importance for the treatment of respiratory infections in elderly people.

A new DIG-PCR-EIA method for the detection of Chlamydia pneumoniae DNA in clinical samples

Chlamydia pneumoniae, a common respiratory pathogen, may also play a role in the pathogenesis of other chronic conditions. For accurate detection of infected persons and verification of results obtained by other PCR methods, a DIG-PCR-EIA method was evaluated. In the DIG-PCR-EIA, a 437 bp DNA sequence was amplified and hybridized with a newly synthesized 229 bp biotin-labeled probe. The end product was detected by an enzyme immunoassay. The sensitivity of DIG-PCR-EIA was compared with Southern blot hybridization and one-step HR/HL PCR, which was the routine method used. DNA was detected to the level of 20 elementary bodies of DIG-EIA-PCR compared to less than 2 by Southern blot, and 200 by HR/HL PCR. Thus a 100-fold increase in sensitivity could be expected by DIG-EIA-PCR compared to the routine method. Throat swabs and adenoid tissue from 22 children with otitis and middle ear secretions from 29 children, as well as throat swabs from 179 blood donors, were analyzed with DIG-EIA-PCR, HL/HR PCR and nested touchdown PCR. 32% of the ear secretions were positive by DIG-EIA-PCR as compared to 5% by the other two methods. Three adenoid tissue samples were positive by all methods applied. Among the child and adult throat samples, 18% and 32%, respectively, were positive by DIG-EIA-PCR and 5% and 10% by HR/HLPCR. The results indicate the suitability of DIG-PCR-EIA for verification of results of HR/HL PCR. DIG-PCR-EIA has a potential for increased sensitivity and adaptation for automation. It should be further evaluated using various types of tissue specimens and DNA extraction methods.

Chlamydia pneumoniae seropositivity is associated with carotid artery intima-media thickness

BACKGROUND AND PURPOSE

Infection may both augment the atherosclerotic process and contribute to later manifestations of overt clinical disease. Chlamydia pneumoniae elementary bodies have been detected in atherosclerotic lesions. The aim of the present study was to investigate whether elevated titers of antibodies and circulating immune complexes to C pneumoniae were associated with ultrasound findings indicating presence of atherosclerosis in the carotid artery.

METHODS

Serum titers of antibodies to C pneumoniae (IgM, IgA, IgG, and circulating immune complex) were related to intima-media thickness (IMT) and plaque status measured by B-mode ultrasound in the carotid artery in 113 men with treated hypertension and at least 1 of the following risk factors: hypercholesterolemia, smoking, or diabetes.

RESULTS

Any of the titers was elevated in 56 (50%) men, and common carotid artery IMT was thicker in this group compared with the 57 men without any elevated titers (1.00 versus 0.92 mm, P<0.05). There were no accompanying differences in blood pressure, lipid levels, blood glucose, or smoking. Elevation of separate antibody types and circulation immune complex were also associated with increased IMT. In the latter group, systolic blood pressure was higher among seropositive patients compared with those who had no circulating immune complex. Seropositivity was not related to plaque status.

CONCLUSIONS

Seropositivity for C pneumoniae was associated with an increased intima-media thickness in the common carotid artery but not plaque status in hypertensive men at high risk for cardiovascular disease.

Chlamydia pneumoniae serology: interlaboratory variation in microimmunofluorescence assay results

The lack of standardization in chlamydia serology has made interpretation of published data difficult. This study was initiated to determine the extent of interlaboratory variation of microimmunofluorescence (MIF) test results for the serodiagnosis of Chlamydia pneumoniae infections. Identical panels of 22 sera were sent to 14 laboratories in eight countries for the determination of IgG and IgM antibodies by MIF. Although there was extensive variation in the numeric titer values, the overall percentage agreement with the reference standard titers from the University of Washington was 80%. For results by serodiagnostic category, the best agreement was for four-fold rise in IgG titers, while the lowest agreement was for negative or low IgG titers. Agreement for IgM titers was 50%-95%. Four laboratories failed to discern false-positive IgM titers possibly because of the presence of rheumatoid factor. Further studies are underway to determine the source of interlaboratory variation for the MIF test.

Detection of viable Chlamydia pneumoniae in abdominal aortic aneurysms

OBJECTIVES

to investigate the presence of Chlamydia pneumoniae in the wall of abdominal aortic aneurysms (AAAs) and in the aortas of patients without a history of cardiovascular disease.

DESIGN

case-control study.

MATERIALS

twenty-six consecutive patients operated for AAA were compared to 17 controls.

METHODS

aorta was obtained at surgery or autopsy (controls) and prepared for immunohistochemical (IHC) analysis and culture for C. pneumoniae. Throat swabs from 14/26 patients were analysed by PCR for C. pneumoniae. Blood was obtained from 24/26 patients and from 178 70-year-old males.

RESULTS

C. pneumoniae was detected in the aortic aneurysms of 20/26 patients by IHC. C. pneumoniae was cultured from 10 of the 20 IHC-positive patients. Only 1/17 controls was positive for C. pneumoniae by IHC (p=0.0001). PCR was positive for C. pneumoniae in 5/14 patients. Serological analysis by microimmunofluoresence (MIF) showed significantly more high titres of the specific antibodies to C. pneumoniae in patients than in age-matched male controls.

CONCLUSIONS

we conclude that C. pneumoniae is often present in AAAs in a viable form and that C. pneumoniae is linked to the pathogenesis of AAA.

Serological analysis of specific IgA to Chlamydia pneumoniae: increased sensitivity of IgA antibody detection using prolonged incubation and high antigen concentration

The microimmunofluorescence technique (MIF) is recognized as the only test hitherto allowing discrimination between different Chlamydia species and is considered to be the reference method for serology. This method was developed for the detection of IgG and IgM antibodies only. We investigated the effects of some test parameters on the ability of MIF to detect Chlamydia pneumoniae IgA. These parameters were the time needed for binding of serum IgA to C. pneumoniae antigen and the effect of antigen concentration on the outcome of IgA antibody testing. It was found that the most sensitive MIF tests for the detection of serum IgA antibodies were those in which an overnight incubation of sera with antigen slides containing high concentrations of chlamydial elementary bodies was employed. The number of patients with chronic infections found to have elevated IgA titers was increased by 25% using longer incubation times for the antibody-antigen reaction. Thirty-two sera from patients with coronary artery disease and confirmed chronic C. pneumoniae infection were used to compare antigen slides with low and high concentrations of elementary bodies with respect to IgA levels; 31/32 patients were found to have specific IgA antibodies to C. pneumoniae using the high antigen concentration, as opposed to only 22/32 patients using the low antigen concentration.

Bordetella pertussis, Bordetella parapertussis, Mycoplasma pneumoniae, Chlamydia pneumoniae and persistent cough in children

Material collected during a prospective pertussis vaccine trial in 1992-95 was examined for Bordetella pertussis (culture and serology), Bordetella parapertussis (culture), Mycoplasma pneumoniae and Chlamydia pneumoniae (PCR). From 64% (99/155) of episodes with cough for less than 100 d, 115 aetiological agents were identified in one southern and one northern subset of DT-recipients. The most common single agent was B. pertussis, representing 56%(64/115), with a median cough period of 51 d, followed by M. pneumoniae 26%(30/115), 23 d, C. pneumoniae 17% (19/115), 26 d, and B. parapertussis 2% (2/115). For co-infections, the median duration of cough was about 60 d. Spasmodic cough for 21 d or more (clinical WHO criteria for pertussis) was present in 82% (41/50) of infections with B. pertussis as single agent, 38% (17/45) with B. parapertussis, 38% (5/13) with C. pneumoniae, 26% (5/19) with M. pneumoniae and 30%(17/56) in cases where no aetiology was found. In children with cough for more than 100 d (n = 78) using all vaccine arms, B. pertussis was responsible in 83% (65/78), in 21%(16/78) together with other agents. Acellular vaccines were more efficient against serious disease than whole cell vaccine. Antibiotic treatment was more common at the southern (34%) study site than at the northern one (12%). The findings indicate that diagnosis should rely on laboratory confirmation, both for rational treatment of an individual case and for monitoring outbreaks.

Chlamydia pneumoniae may be associated with lung cancer. Preliminary report on a seroepidemiological study

Material from 117 consecutive patients with lung cancer was investigated with respect to serological markers for chronic Chlamydia pneumoniae infection. Specific C. pneumoniae IgA antibodies were found significantly more often in patients with lung cancer than in control groups with coronary heart disease and in healthy controls, even after adjustment for smoking. The results suggest that chronic C. pneumoniae infection is common in patients with lung cancer.

Evidence of 2 waves of Chlamydia pneumoniae infection in Gävle, Sweden, 1990-96

Chlamydia pneumoniae is a common respiratory tract pathogen. The majority of adults have serological evidence of previous exposure. Most infections are probably asymptomatic or subclinical. Recent studies have implicated C. pneumoniae as a risk factor for the development of cardiovascular disease. It was therefore of interest to study new blood donors collected between the years of 1990 and 1996 for the purpose of delineating the epidemiological situation in the Gävle area of Sweden. Sera from all first time blood donors over a 7 y period were tested for IgG, IgA and IgM antibodies to C. pneumoniae with a microimmunofluorescence test (MIF). Donors were subjectively healthy individuals between 18 and 65 y of age, (913 M, 752 F). Exposure to C. pneumoniae, expressed in terms of specific IgG antibodies in titres of > 1/32, increased for men in 1990-92 and for women in 1990-93. There was a decrease the following year for both sexes, followed by another increase in 1994-95. IgG antibodies in titres of > or = 512, and IgA antibodies in titres of > or = 1/64, were increased in 1990-91 for men and in 1994-96 for both sexes. The prevalence of specific antibodies increased throughout the 7 y period except for women 1995-96. Men had higher antibody titres than women throughout the entire study period. The results indicate that two waves of largely subclinical infection occurred in our area over the years 1990-96.

Chlamydia pneumoniae infection associated with multi-organ failure and fatal outcome in a previously healthy patient

Chlamydia pneumoniae has been associated with respiratory infections and with cardiovascular disease. We describe here a patient with multi-organ failure and fatal outcome in whom C. pneumoniae was implicated as a causative agent. Serological analysis for C. pneumoniae was done by immunofluorescence. Immunohistochemistry was carried out with avidin-biotin peroxidase staining. The patient had pneumonia I month prior to death. C. pneumoniae was detected in the heart and lungs by immunohistochemistry at autopsy. The patient had an antibody pattern suggestive of current or chronic C. pneumoniae infection. Serological analysis for Legionella sp., Mycoplasma pneumoniae, CMV, EBV, enteroviral agents and markers for autoimmune disease were negative. The findings suggest C. pneumoniae as the aetiological agent in this case of multi-organ failure.

Chlamydia pneumoniae but not cytomegalovirus antibodies are associated with future risk of stroke and cardiovascular disease: a prospective study in middle-aged to elderly men with treated hypertension

BACKGROUND AND PURPOSE

Several cross-sectional and prospective studies have indicated that high titers of antibodies to Chlamydia pneumoniae and cytomegalovirus (CMV) are associated with coronary heart disease. The aim of the present study was to examine whether elevated titers of antibodies to these pathogens are predictive of not only coronary but also cerebrovascular disease.

METHODS

Serum titers of antibodies to C pneumoniae (IgM, IgG, IgA, IgG immune complex) and CMV (IgG) were determined at baseline (n=130) and after 3.5 years (n=111) in a total sample of 152 men. All individuals had treated hypertension and at least 1 additional risk factor for cardiovascular disease (hypercholesterolemia, smoking, or diabetes mellitus) and constituted 93% of a randomly selected subgroup (n=164) of patients participating in a multiple risk factor intervention study.

RESULTS

Elevations of any or both of the IgA or IgG titers to C pneumoniae at entry or after 3.5 years were found in 84 cases (55%). Of those with high titers at entry, 97% remained high at the 3.5 year reexamination. After 6.5 years of follow-up, high titers to C pneumoniae at entry were associated with an increased risk for future stroke (relative risk [RR], 8.58; P=0.043; 95% CI, 1.07 to 68.82) and for any cardiovascular event (RR, 2.69; P=0.042; 95% CI, 1.04 to 6.97). A high serum titer of antibodies to CMV was found in 125 cases (85%), and this was not associated with an increased risk of future cardiovascular events.

CONCLUSIONS

Seropositivity for C pneumoniae, but not for CMV, was associated with an increased risk for future cardiovascular disease and, in particular, stroke.

Association of Chlamydia pneumoniae with otitis media in children

Chlamydia pneumoniae is a common cause of acute and persistent respiratory tract infections. The prevalence of C. pneumoniae was studied using the polymerase chain reaction (PCR) in throat swabs from 85 consecutive children with respiratory tract infections and 86 healthy children. In retrospect, it became evident that this study was conducted in the midst of a local C. pneumoniae epidemic. 38 (45%) of the sick children and 5 (5.7%) of the healthy children were positive for C. pneumoniae by PCR. 26 of the sick children (mean age 6.4 years) were found to have otitis media either at the time of examination or shortly thereafter. Six of 9 children with acute otitis media were PCR positive for C. pneumoniae and 7 of the 9 had specific antibody responses indicating active infection. 10 of 17 children diagnosed as having otitis media with effusion were found to be positive for C. pneumoniae by PCR. Seven children had or developed persistent otitis media with effusion. Chlamydia pneumoniae was demonstrated by PCR from the middle ear fluid in 1 of the children. The results obtained from this study indicate that C. pneumoniae may be involved in the aetiology of otitis media.

The prevalence of chronic Chlamydia pneumoniae infection as detected by polymerase chain reaction in pharyngeal samples from patients with ischaemic heart disease

AIMS

Cross-sectional serological studies have suggested an association between ischaemic heart disease and infections from Chlamydia pneumoniae and Helicobacter pylori. We therefore sought to find out if patients with ischaemic heart disease had an increased prevalence of C. pneumoniae in the pharynx. As the course of the C. pneumoniae infection remains unclear, both acute and follow-up samples were taken and compared with antibody levels.

METHODS AND RESULTS

We studied 282 patients with ischaemic heart disease. One hundred and two subjects without history or symptoms of ischaemic heart disease served as controls. Pharyngeal specimens for polymerase chain reaction detection of C. pneumoniae, and blood samples for C. pneumoniae and H. pylori antibody detection, were collected. In patients with positive polymerase chain reaction or C. pneumoniae IgA titres > or = 32, indicating current infection, convalescent samples were taken at least 6 weeks later. An immunofluorescent antigen detection test was used to confirm the presence of C. pneumoniae elementary bodies in specimens found to be polymerase chain reaction positive. The prevalence of positive polymerase chain reaction tests was 36% among patients and 22% among controls (P<0.05). Forty-seven percent of patients with positive polymerase chain reaction remained positive in the convalescent test. Elevated C. pneumoniae IgG titres > or = 512 were found in 39% of patients and 26% of the controls (P<0.05). IgA titres > or = 32 were found in 46% of the patients and 44% of the controls (ns). Antibody titres remained largely unchanged at convalescent testing. Two patients and none of the controls had IgM titres > 16. There was no link between positive H. pylori serology and positive C. pneumoniae polymerase chain reaction tests.

CONCLUSIONS

The high prevalence and persistence of positive pharyngeal C. pneumoniae polymerase chain reaction and elevated antibody titres in patients with ischaemic heart disease indicate a chronic infection. The pharyngeal presence of C. pneumoniae might contribute to a low grade inflammatory activation or be a source for further spread of the bacteria to atherosclerotic vessels.

Helicobacter pylori serology in elderly people: a 21-year cohort comparison in 70-year-olds and a 20-year longitudinal population study in 70-90-year-olds

AIMS

(i) to compare Helicobacter pylori serology in two 70-year-old cohorts in Gothenburg, Sweden, born 21 years apart, (ii) to study H. pylori serology in a 70-year-old cohort over 20 years.

POPULATION AND METHOD

H. pylori serology at the age of 70 was investigated in 98 men and 132 women born in 1901/02 and in 77 men and 113 women born in 1922. In 21 men and 40 women Helicobacter serology was monitored longitudinally with examinations at 70, 81, and 90 years of age. The analyses were performed on frozen samples by use of an in-house enzyme immunoassay with a sensitivity of 0.99, specificity of 1.00 and positive and negative predictive values of 0.96 and 1.00, respectively. Absorbance values <0.500 were interpreted as negative; values of > or = 0.700 were interpreted as positive, and values in between as inconclusive.

RESULTS

The 70-year-old cohort, born in 1922, showed a significantly lower proportion of subjects with positive H. pylori serology in both men (57.1% vs 80.6%) and women (48.7% vs 75.8%) compared with 70-year-olds born in 1901/02. There were no significant sex differences in either cohort. No longitudinal increase or decrease could be demonstrated in those who were examined at 70, 81 and 90 years of age.

CONCLUSIONS

The difference in H. pylori prevalence between the two cohorts may reflect a rapid change in socio-economic conditions in Sweden during this 20-year period.

Chlamydia pneumoniae in children attending day-care centers in Gävle, Sweden

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 < 0.01). No correlation was found between respiratory symptoms and carriage of C. pneumoniae. Mothers were more often positive in the PCR test as compared with fathers (relative risk, 2.59; 95% confidence interval, 1.16 to 5.78). Antibodies to C. pneumoniae were found in 27 of 97 PCR-positive children; only 2 of whom were younger than 3 years.

CONCLUSION

C. pneumoniae can be commonly found in young children attending day care. Most of the youngest children did not develop specific antibodies. Children may have subclinical infections with C. pneumoniae. The organism seems to be easily communicable among individuals living in close proximity.

Demonstration of Chlamydia pneumoniae in patients with chronic pharyngitis

12 patients with longstanding throat symptoms, who were also positive by PCR (polymerase chain reaction) for Chlamydia pneumoniae were selected for a longitudinal study to determine whether C. pneumoniae is an aetiological agent for chronic pharyngitis. Specimens for culture and PCR detection of C. pneumoniae were taken from the retropharyngeal wall and blood specimens were taken for serology. Biopsies were taken from the mucosal membrane of the retropharyngeal wall for histological and immunohistochemical studies. C. pneumoniae was cultured from 4 cases. 10 patients had specific humoral antibodies to C. pneumoniae and 9 had high and increasing specific antibody titres to C. pneumoniae suggesting ongoing infection. The organism was demonstrated in the tissue from the retropharyngeal mucosal membrane by immunohistochemistry in 9 patients. The findings suggest that C. pneumoniae may be an aetiological agent for chronic pharyngitis.

Increased fibrinogen levels are associated with persistent Chlamydia pneumoniae infection in unstable coronary artery disease

AIM

Increased levels of acute phase proteins, e.g., fibrinogen, are related to a poor outcome in unstable coronary artery disease, but the cause of inflammation is unknown. We therefore investigated the prevalence of persistent Chlamydia pneumoniae infection, and its relationship to inflammation in this condition.

METHODS AND RESULTS

In 256 patients participating in the FRISC trial, evaluating the effects of dalteparin (a low molecular weight heparin) in unstable angina or non-Q wave myocardial infarction, Chlamydia pneumoniae IgA antibody titres and levels of fibrinogen, C-reactive protein and troponin T were determined at inclusion. Increased C. pneumoniae IgA antibody titres were significantly more common in the patients (36%) than in a reference population of similar age (19%); P < 0.001. Raised titres were associated with male gender, increasing age, smoking, and elevated concentrations of fibrinogen, C-reactive protein and troponin T. The association between persistent C. pneumoniae infection and increased fibrinogen levels was independent of other risk factors evaluated in multivariate analysis (P = 0.009).

CONCLUSION

Persistent C. pneumoniae infection is common in unstable coronary artery disease. The independent association between increased C. pneumoniae IgA antibody titres and fibrinogen levels indicates that chronic infection could be of importance for disease activity.

Chlamydia pneumoniae in children with acute respiratory tract infections

Children seeking medical attention for acute respiratory tract infections were investigated for evidence of Chlamydia pneumoniae infection. Blood samples were obtained from 367 children. Nasopharyngeal or throat swabs for PCR analysis (polymerase chain reaction) were taken from 360 children. Serology was found to be useful for diagnosis of infection only in children aged > 5 y. Using PCR, a prevalence of 8 and 10% of C. pneumoniae was found in male and female children aged < 2 y; 17 and 19%, respectively, in the age group 2-4 y and 32 and 21%, respectively, in the age group 5-16 y. We conclude that Chlamydia pneumoniae is a common finding in young children with respiratory tract infections. Younger children were more often found to have a moderate disease, but may have been ill for a long period.

Prevalence of Chlamydia pneumoniae in healthy children and in children with respiratory tract infections

BACKGROUND

Chlamydia pneumoniae causes respiratory tract infections in adults, but little is known about its significance for acute or persistent respiratory tract infections in children.

METHODS

We studied the prevalence of C. pneumoniae by polymerase chain reaction in children younger than the age of 11: 85 consecutive children with respiratory tract infections; and 93 children presumed to be healthy. Throat swabs for PCR analysis were taken from all children, and serology was done for 54 of the 85 sick children and from all but one of the presumed healthy children positive for C. pneumoniae by PCR.

RESULTS

PCR was positive in 38 (45%) of the sick children and in 5 (5.7%) of the healthy children. All but 2 of 19 sick children with serologic findings suggesting recent or ongoing infection with C. pneumoniae were positive by PCR. Most children positive for C. pneumoniae by PCR had upper respiratory tract infections. Four children had recurrent respiratory tract infections and otitis media with effusion treated by tubal insertion.

CONCLUSION

The findings suggest that C. pneumoniae is common among children with respiratory tract infections.

Comparison of nasopharyngeal and throat swabs for the detection of Chlamydia pneumoniae and Mycoplasma pneumoniae by polymerase chain reaction

Nasopharyngeal and throat swabs taken from 66 patients presenting at the Department of Infectious Disease with symptoms of upper and lower respiratory tract infection were analysed by use of the polymerase chain reaction (PCR) for Chlamydia pneumoniae and Mycoplasma pneumoniae. A total of 18 patients (27%) were positive by PCR for C. pneumoniae. All 18 patients were positive from throat swabs, and three were also positive from nasopharyngeal specimens. The difference between the outcome of PCR using throat and nasopharyngeal swabs was statistically significant. A total of 7 patients (10.6%) were positive for M. pneumoniae and of these, 6 were positive from throat swabs and 2 were positive from nasopharyngeal swabs. This difference was not statistically significant, probably due to the low numbers of positive patient specimens.

Chlamydia pneumoniae and myocarditis

Sera from 20 male patients with a diagnosis suggestive of myocarditis, perimyocarditis or pericarditis were found significantly more often to have specific IgA antibodies to Chlamydia pneumoniae than sera from healthy blood donors of the same age and from the same time period. A less pronounced difference in IgG titres was found between patients and blood donors, and IgM antibodies were found only in one patient. A striking variation over time in the prevalence of specific antibodies to C. pneumoniae was seen in consecutive male blood donors over a 5-year observation period. The findings were discussed and it was concluded that C. pneumoniae may be associated with inflammatory heart disease.

In vitro activities of azithromycin and doxycycline against 15 isolates of Chlamydia pneumoniae

Fourteen isolates of Chlamydia pneumoniae, 12 from clinically ill patients and 2 from subjectively healthy individuals from an area within a 400-km proximity of Gävle, Sweden, and strain IOL-207, originally from the eye of an Iranian child, were tested for susceptibilities to the antibiotics doxycycline and azithromycin. MICs and minimum chlamydiacidal concentrations were found to correlate well with values reported earlier by other investigators. In addition to MIC and minimum chlamydiacidal concentration testing, testing for the viability of C. pneumoniae after exposure to antibiotic concentrations as high as 50 mg/liter was carried out by passaging antibiotic-treated, infected cell cultures four times in the absence of antibiotics. It was found that all Chlamydia strains were viable after four passages, regardless of antibiotic concentration in the cell culture.

An increase in sudden unexpected cardiac deaths among young Swedish orienteers during 1979-1992

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.