Chlamydia pneumoniae, strain TWAR

Evidence for the existence of two new members of the family Chlamydiaceae and proposal of Chlamydia avium sp. nov. and Chlamydia gallinacea sp. nov

The family Chlamydiaceae with the recombined single genus Chlamydia currently comprises nine species, all of which are obligate intracellular organisms distinguished by a unique biphasic developmental cycle. Anecdotal evidence from epidemiological surveys in flocks of poultry, pigeons and psittacine birds have indicated the presence of non-classified chlamydial strains, some of which may act as pathogens. In the present study, phylogenetic analysis of ribosomal RNA and ompA genes, as well as multi-locus sequence analysis of 11 field isolates were conducted. All independent analyses assigned the strains into two different clades of monophyletic origin corresponding to pigeon and psittacine strains or poultry isolates, respectively. Comparative genome analysis involving the type strains of currently accepted Chlamydiaceae species and the designated type strains representing the two new clades confirmed that the latter could be classified into two different species as their average nucleotide identity (ANI) values were always below 94%, both with the closest relative species and between themselves. In view of the evidence obtained from the analyses, we propose the addition of two new species to the current classification: Chlamydia avium sp. nov. comprising strains from pigeons and psittacine birds (type strain 10DC88(T); DSMZ: DSM27005(T), CSUR: P3508(T)) and Chlamydia gallinacea sp. nov. comprising strains from poultry (type strain 08-1274/3(T); DSMZ: DSM27451(T), CSUR: P3509(T)).

Chlamydophila pneumoniae attachment and infection in low proteoglycan expressing human lymphoid Jurkat cells

This study investigated the proteoglycan (PG)-dependent mechanism of Chlamydophila pneumoniae attachment to lymphocytic cells. Lymphoid Jurkat cells and epithelial HEp-2 cells were statically infected with C. pneumoniae (TW183). Transmission electron microscopy and assessment of inclusion-forming units indicated that the bacteria grew normally in Jurkat cells and were capable of producing secondary infection; however, they grew at a slower rate than in HEp-2 cells. RT-PCR analysis indicated that HEp-2 cells strongly expressed PG-core protein encoding genes, thereby sustaining glycosaminoglycans (GAGs), such as heparin, on the cellular surface. Similar gene expression levels were not observed in Jurkat cells, with the exception of glypican-1. Immunofluorescence analysis also supported strong heparin expression in HEp-2 cells and minimal expression in Jurkat cells, although heparan sulfate pretreatment significantly inhibited bacterial attachment to both cell types. Immunofluorescent co-staining with antibodies against chlamydial LPS and heparin did not identify bacterial and heparin co-localization on Jurkat cells. We also confirmed that when C. pneumoniae was statically infected to human CD4(+) peripheral blood lymphocytes known not expressing detectable level of heparin, the bacteria attached to and formed inclusion bodies in the cells. Thus, the attachment mechanism of C. pneumoniae to Jurkat cells with low PG expression is unique when compared with HEp-2 cells and potentially independent of GAGs such as heparin.

Detection of Mycoplasma pneumoniae, Chlamydia pneumoniae, and Legionella spp. in clinical specimens using a single-tube multiplex real-time PCR assay

A multiplex real-time PCR assay for the detection of Mycoplasma pneumoniae (MP181), Chlamydia (Chlamydophila) pneumoniae (CP-Arg), Legionella spp. (Pan-Leg), and the human RNase P (RNase P) gene was developed for rapid testing of atypical bacterial respiratory pathogens in clinical specimens. This method uses 4 distinct hydrolysis probes to detect 3 leading causes of community-acquired pneumonia. The assay was evaluated for specificity and sensitivity by testing against 35 related organisms, a dilution series of each specific target and 197 clinical specimens. Specificity testing demonstrated no cross-reactivity. A comparison to previously validated singleplex real-time PCR assays for each agent was also performed. The analytical sensitivity for specific pathogen targets in both the singleplex and multiplex was identical (50 fg), while efficiencies ranged from 82% to 97% for the singleplex assays and from 90% to 100% for the multiplex assay. The clinical sensitivity of the multiplex assay was improved for the Pan-Leg and CP-Arg targets when compared to the singleplex. The MP181 assay displayed equivalent performance. This multiplex assay provides an overall improvement in the diagnostic capability for these agents by demonstrating a sensitive, high-throughput and rapid method. This procedure may allow for a practical and efficient means to test respiratory clinical specimens for atypical pneumonia agents in health care settings and facilitate an appropriate public health response to outbreaks.

Endosymbiotic bacterium Protochlamydia can survive in acanthamoebae following encystation

Obligate intracellular bacteria are commonly seen as endosymbionts of acanthamoebae. However, whether endosymbionts can survive amoebal encystations remains a significant challenge in cellular biology. The survival of the endosymbiotic bacteria Protochlamydia belonging to environmental chlamydiae found in an amoebal isolate that we have previously reported (Environmental Microbiology Reports, DOI: 10.1111/j.1758-2229.2009.00094.x, 2009) following encystation was therefore assessed. The bacteria were observed in cysts and trophozoites reverted from cysts by analysis with transmission electron microscope, and the bacterial 16S rRNA transcripts were detected in amoeba cultures following encystations by reverse transcription polymerase chain reaction method. Furthermore, the bacterial growth was also confirmed, by fluorescent in situ hybridization analysis and the AIU assay that we have previously established (Applied Environmental Microbiology, 74: 6397-6404, 2008), in trophozoites reverted from cysts stored at 4°C for up to a month after encystation. Thus, these results demonstrated that Protochlamydia could survive in acanthamoebae following encystation. Our findings suggest that amoeba cysts might be further studied in order to understand their role in the environmental survival of endosymbionts.

Stability of Chlamydophila pneumoniae in a harsh environment without a requirement for acanthamoebae

The effect of actual interactions between Chlamydophila pneumoniae and amoebae (Acanthamoeba) on the survival of C. pneumoniae was investigated. C. pneumoniae and amoebae were detected in 75 soil samples by IFU assay and PCR. Although C. pneumoniae could not be cultured, the DNA prevalence of C. pneumoniae and amoebae in natural soil was 20% and 92% (no correlation between the prevalence of DNA was observed). The viability of C. pneumoniae spiked in autoclaved soil was assessed by IFU assay and RT-PCR. Although the number of infective progeny decreased for three days, transcripts of C. pneumoniae were detected for up to 98 days independently of amoebae. The stability of C. pneumoniae in liquid medium was also assessed by IFU assay and transmission electron microscopy. The bacteria could survive at 15 degrees C for 14 days independently of amoebae. Bacteria cultured without amoebae were confirmed to have normal structures. Thus, the presence of amoebae has no effect on C. pneumoniae survival, and the bacteria can survive in the absence of host cells for an extended period of time.

Inhibition of lymphocyte CD3 expression by Chlamydophila pneumoniae infection

Since lymphocytes are a major immune cell besides macrophages in the development of atherosclerosis, interaction between lymphocytes and Chlamydophila pneumoniae may contribute to the pathogenesis of chronic inflammatory diseases associated with C. pneumoniae. In this regard, we examined a possible alteration of CD3 expression of human lymphocyte Molt-4 cells by C. pneumoniae infection. The expression levels of CD3 molecules of lymphocyte Molt-4 cells were significantly decreased by C. pneumoniae infection. In contrast, heat-killed C. pneumoniae as well as mock (cell lysates) did not cause any alteration of CD3 expression of the cells. Treatment of the infected cells with NS-398 (cyclo-oxyganase-2 inhibitor) or AH-23848 (EP(4) prostanoid receptor antagonist) abolished the inhibition of CD3 expression. The enhanced prostaglandin E(2) (PGE(2)) productions in the culture supernatants of infected cells were confirmed by competitive enzyme-immunosorbent assay (ELISA). C. pneumoniae infection of enriched lymphocytes from human peripheral blood mononuclear cells also induced a decrease of CD3 expression. Thus, C. pneumoniae infection of lymphocytes induces a decrease of CD3 expression mediated by possibly PGE(2) production.

Chlamydia pneumoniae GroEL1 protein is cell surface associated and required for infection of HEp-2 cells

Chlamydia pneumoniae is an important obligate intracellular pathogen that replicates within an inclusion in the eukaryotic cell. The initial event of a chlamydial infection is the adherence to and subsequent uptake of the infectious elementary bodies (EBs) by the human cell. These processes require yet-unidentified bacterial and eukaryotic surface proteins. The GroEL1 protein, which exhibits a very strong antigenicity and in vitro can activate various eukaryotic cells, is a potential pathogenicity factor. We localized the protein during the infection process and found it in the inclusion but outside the chlamydial particles. GroEL1 was also localized on the surface of EBs, and the protein could be washed off the EBs. Latex beads coated with recombinantly produced GroEL1 (rGroEL1) bound in a dose-dependent manner to HEp-2 cells. Likewise, GroEL1, when expressed and displayed on the yeast cell surface, mediated adhesion to HEp-2 cells. Interestingly, the homologous GroEL2 and GroEL3 proteins showed no adhesive properties. Incubation of primary umbilical vein endothelial cells with soluble GroEL1 and GroEL1-coated latex beads activated the translocation of the general transcription factor NF-kappaB into the nucleus. Finally, preincubation of HEp-2 cells with rGroEL1 significantly reduced subsequent infection with C. pneumoniae, although adhesion of infectious bacteria to eukaryotic cells was not affected. Taken together, these data support a role for extracellular GroEL1 in the establishment of the chlamydial infection.

Acute exacerbation of idiopathic pulmonary fibrosis: role of Chlamydophila pneumoniae infection

BACKGROUND AND OBJECTIVES

Patients with idiopathic pulmonary fibrosis (IPF) may experience acute exacerbations of their illness. The actual trigger(s) of such exacerbations is unknown. Chlamydophila pneumoniae infection can cause exacerbation of asthma and COPD. A prospective study was conducted to investigate the possible role of C. pneumoniae infection in triggering acute exacerbations of IPF.

METHODS

A prospective observational study over 5 years of consecutive IPF patients who fulfilled the criteria for acute exacerbation. Sputum, blood cultures and acute and convalescent serology for C. pneumoniae IgG and IgA (ELISA) were performed.

RESULTS

Previous infection with C. pneumoniae is common. Of the 27 study patients, 15 had a C. pneumoniae IgG index of 1.10-2.99 (positive) and 3 had a C. pneumoniae IgG index of >2.99 (strongly positive) at the time of presentation with an acute exacerbation. In addition, 15 subjects had a C. pneumoniae IgA index of 1.10-2.99 (positive) and 6 subjects had a C. pneumoniae IgA index of >2.99 (strongly positive). However, only two of the 15 subjects (13%) for whom paired sera were tested exhibited a significant rise in antibody response (change in index of 1.90 for C. pneumoniae IgG and 1.54 for IgA, respectively) indicating either acute or reactivated infection with C. pneumoniae. There were 15 deaths (56%) despite supportive care that included high-dose corticosteroid therapy and oxygen supplementation.

CONCLUSIONS

Mortality is high with acute exacerbation of IPF. Acute infection with C. pneumoniae is uncommon at the time of presentation with acute exacerbation of IPF.

Successful removal of Chlamydia pneumoniae from plateletpheresis products collected using automated leukoreduction hemapheresis techniques

Chlamydia pneumoniae (Cp) is an obligate intracellular pathogen associated with a variety of maladies. Best known for its involvement in community-acquired pneumonia outbreaks; the potential role of Cp in diverse illnesses is a topic of increasing interest and investigation. Previous studies suggested that white blood cells from normal blood donors harboring this agent may be eliminated through leukoreduction by filtration. Here we examine the ability and efficacy of apheresis-related leukoreduction for its effect on the carriage and potential infectivity of these organisms in the preparation of platelet products. Matched pre-apheresis peripheral blood (PB) samples and product samples obtained from healthy plateletpheresis donors were analyzed for the presence and potential infectivity of Cp organisms by direct smear inspection and tissue culture techniques. Antibody seroreactivity directed towards the organism was assessed using a solid phase immunoassay. Forty-eight percent of the donor blood samples exhibited elevated anti-Cp antibody titers (> or =200). Specimens from 31 (27%) and 34 (30%) of 115 plateletpheresis donors were positive for the presence of Cp organisms in their pre-apheresis PB samples when analyzed by direct smear examination and culture, respectively. Examination of the 115 post-leukodepleted plateletpheresis product samples revealed only two (1.7%) and one (0.009%) product(s) to be smear-positive and culture-positive, respectively. Certain plateletpheresis donors may harbor infectious Cp organisms in circulating WBC. Collections from such donors of apheresis platelet products using standard apheresis leukoreduction strategies appear successful in markedly decreasing or eliminating the organisms found in the final products.

Chlamydophila pneumoniae and Mycoplasma pneumoniae: a role in asthma pathogenesis?

The potential role of atypical bacterial infection in the pathogenesis of asthma is a subject of continuing debate. There is an increasing body of literature concerning the association between the atypical bacteria Chlamydophila pneumoniae and Mycoplasma pneumoniae and asthma pathogenesis; however, many studies investigating such a link have been uncontrolled and have provided conflicting evidence, in part due to the difficulty in accurately diagnosing infection with these atypical pathogens. This article reviews the evidence for an association between atypical bacterial respiratory pathogens and the pathogenesis of asthma, and discusses the biological mechanisms that could account for such a link. The possible role of antibacterial therapy in the management of asthma and the need for well-designed studies to investigate this is also discussed.

Evaluation of lung function in pigs either experimentally or naturally infected with Chlamydiaceae

This study evaluated the influence of chlamydial infections on lung function in conventionally raised pigs. Eight pigs aged 39-44 days were included in an aerogeneous challenge model (4 were exposed to Chlamydia suis; 4 served as controls). Nineteen pigs aged 5-27 weeks without clinical symptoms (but partly PCR-positive for chlamydial species) were examined over 6 months. For lung function testing, impulse oscillometry was used. In total, all 27 pigs underwent 465 lung function tests. Variables of ventilation (respiratory rate, tidal volume, minute volume), respiratory impedance (expressed as resistance and reactance within the frequency range 3-15 Hz), and model derived resistance of proximal and distal airways were measured. Experimental exposure to C. suis significantly affected lung function. Early distal airway obstruction (3-5 days after infection) was followed by an obstruction of proximal airways (7 days after infection). The breathing pattern was significantly changed (decreased tidal volume; increased respiratory rate). In symptom-free pigs having a naturally acquired presence of different chlamydial species in the respiratory system, no deterioration in lung function could be determined up to the age of 6 months. In conclusion, the consequences of respiratory chlamydial infections appear to vary from clinical inapparence to severe respiratory distress.

Seroprevalence of Mycoplasma pneumoniae and Chlamydia pneumoniae in stable asthma and chronic obstructive pulmonary disease

Mycoplasma pneumoniae and Chlamydia pneumoniae have been suggested to take part in the acute exacerbation of bronchial asthma and chronic obstructive pulmonary disease (COPD). Several studies have questioned whether they may play pathogenic roles in connection with bronchial asthma and COPD. This study was designed to evaluate the seroprevalences of M. pneumoniae and C. pneumoniae in stable asthma and COPD patients, and to compare with control patients. The medical records of one hundred forty patients who underwent M. pneumoniae and C. pneumoniae serology were retrospectively reviewed. Seroprevalences of M. pneumoniae and C. pneumoniae in the asthma group (11.1% and 8.3%, respectively) were higher than in the control group (4.4% and 2.2%, respectively) without statistical significance. The seroprevalence of M. pneumoniae in the COPD group (16.9%) was significantly higher than in the control group, and the seroprevalence of C. pneumoniae in the COPD group (3.4%) was higher than in the control group without statistical significance. This study raises important questions about the relation of M. pneumoniae and C. pneumoniae infection with stable asthma or COPD.

Cytokine response of lymphocytes persistently infected with Chlamydia pneumoniae

Chlamydia pneumoniae infection of lymphocytes in blood has been documented, and it is apparent that control of this pathogen in lymphocytes as well as immune functions of the infected lymphocytes may be critical in the development of chronic inflammatory diseases associated with infection by this bacterium. Since immune function of lymphocytes infected with C. pneumoniae has not been well studied, the cytokine response of lymphocytes infected with this pathogen was analyzed using an in vitro infection model of the Molt-4 human lymphoid cell line. C. pneumoniae infection of the cells showed a persistent infection without any vigorous growth of the bacteria. Analysis of the cytokine response of the cells persistently infected with C. pneumoniae showed minimum induction of inflammatory cytokine TNF-alpha message, determined by real-time reverse transcription (RT)-PCR in the lymphocytes, even though the infection of THP-1 monocytic cells showed a marked induction of this cytokine messages. BIC (a lymphocyte activation marker gene) as well as IFN-gamma messages were also minimally induced by the infection in Molt-4 lymphocytes. In contrast, constitutive expression of interleukin 8 (IL-8) messages of Molt-4 cells was suppressed by the infection. Thus, these results suggest that lymphocytes persistently infected with C. pneumoniae may have attenuated cytokine responses.

Association of Peripheral Mononuclear Cells Containing Chlamydia Pneumoniae DNA with Acute Coronary Syndrome and Stable Coronary Artery Disease in Japanese Subjects

To clarify the association of Chlamydia pneumoniae DNA in peripheral blood mononuclear cells (PBMCs) with acute coronary syndrome (ACS) and stable coronary artery disease (CAD) in Japanese adults, touchdown-nested polymerase chain reaction was used to detect the presence of C. pneumoniae DNA. The prevalence of C. pneumoniae DNA in PBMCs was similar in a comparison of 88 patients (52.3%) with ACS, 164 patients (50.0%) with stable CAD, and 88 control subjects (50.0%). Temporal changes in the prevalence of C. pneumoniae DNA in PBMCs were also assessed every 3 months during a 1-year period (n=59). The prevalence was significantly higher in the first 3-month period (January through March) than in any of the other 3-month periods. In conclusion, the prevalence of C. pneumoniae DNA in PBMCs in patients with ACS or stable CAD was comparable to that in control populations. Furthermore, the presence of circulating C. pneumoniae was strongly associated with seasonal variability.

Changes in antibody titers against Chlamydia pneumoniae after coronary angioplasty

OBJECTIVES

The potential role of common infectious agents in the pathogenesis and progression of atherosclerosis has been studied increasingly over the last decade. The evidence for Chlamydia pneumoniae as a potential causative agent is strong and is based on the findings of numerous sero-epidemiological studies, examination of atheromatous plaque specimens, in vitro animal models. We performed a prospective study in percutaneous transluminal coronary angioplasty (PTCA) patients to investigate whether the angioplasty procedure influenced the specific humoral immune response reaction against C. pneumoniae antigens.

METHODS

We studied 76 patients who successfully underwent PTCA for de novo lesions. Blood samples were drawn immediately before PTCA and 1 month after PTCA. IgG and IgA antibodies against C. pneumoniae (strain CDC/CWL-029) were determined by an in-house developed enzyme immunoassay.

RESULTS

At the time of angioplasty 75% and 34% of the patients had seropositive antibodies to elementary bodies (EBs) of classes IgG and IgA, respectively. Mean titers of IgG antibodies before and 1 month after PTCA were 46+/-31 and 50+/-28 relative units (RU/ml) (P>0.05). One month after PTCA, 97% and 34% of the patients had seropositive antibodies to EBs of classes IgG and IgA, respectively. We divided our patients into two groups on the basis of IgG seropositivity (group I: Chlamydia antibody IgG seronegative patients, group II: Chlamydia antibody IgG seropositive) before PTCA. Significant increase in the antibody titers of IgG (12+/-5 vs. 40+/-18, P<0.001) and IgA (0.6+/-0.33 vs. 1.15+/-0.83, P=0.007) was observed in group I patients 1 month after PTCA and 88% of them gained IgG seropositivity. There were no significant changes in IgG and IgA antibody levels in group II after PTCA.

CONCLUSION

We have demonstrated a statistically significant rise in C. pneumoniae antibodies (especially IgG) induced by PTCA in patients previously seronegative.

DETECTION OF CHLAMYDIA PNEUMONIAE IN LIVER TRANSPLANT PATIENTS WITH CHRONIC ALLOGRAFT REJECTION

BACKGROUND

Chlamydia pneumoniae is one of the possible pathogenetic factors of atherosclerotic processes. Foam cell arteriopathy is a generally accepted pathologic feature of chronic liver allograft rejection and has several similarities to the early lesions of atherosclerosis. The aim of the authors' study was to show any existing correlation between the occurrence of Chlamydia pneumoniae and the presence of foam cell arteriopathy in transplanted livers with chronic rejection.

METHODS

Ten liver samples from patients with chronic liver rejection including foam cell arteriopathy and 10 liver samples from healthy individuals were analyzed for the presence of Chlamydia pneumoniae by specific immunohistochemistry and polymerase chain reaction (PCR). Liver samples from two transplant patients with chronic liver rejection without any evidence of foam cell arteriopathy and nine patients with acute liver allograft rejection were also investigated by PCR.

RESULTS

In all 10 rejected liver samples, Chlamydia pneumoniae was detected by PCR, whereas only one of the healthy control samples and one of the samples with acute rejection were found to be positive. Immunohistochemistry showed similar results. The positive signals of Chlamydia pneumoniae were localized mainly in the hepatocytes, sinusoidal and perisinusoidal cells, and the cells of portal tracts, whereas most of the altered hepatic arteries showed no or very weak positivity.

CONCLUSIONS

The results strongly suggest an association between the occurrence of Chlamydia pneumoniae and the presence of foam cell arteriopathy in transplanted livers.

Chronic Chlamydophila pneumoniae infection in lung cancer, a risk factor: a case-control study

The relationship between chronic Chlamydophila (formerly Chlamydia) pneumoniae infection and lung carcinoma was investigated. A total of 123 patients who were smokers and diagnosed with lung carcinoma based on clinical and laboratory (radiological, cytological) findings were examined. Of these patients, 70 had small-cell, 28 squamous-cell and seven large-cell carcinomas, while 18 had adenocarcinoma. A total of 123 healthy persons matching patients in age, sex, duration of smoking and locality were chosen as controls. Blood samples (5 ml) were withdrawn at the time of diagnosis and 1 month later. The values between IgG >/= 512 and IgA >/= 40 were set as the criteria for chronic Chlamydophila pneumoniae infections. In male patients with lung carcinoma, Chlamydophila pneumoniae IgG antibody titres of >/= 512 and IgA antibody titres of >/= 40 were found at a higher rate than in the control group. This ratio was not significant for the female patients. In chronic Chlamydophila pneumoniae infections, Chlamydophila pneumoniae antibody titres with values IgG >/= 512 and IgA >/= 40 were found in a total of 62 (50.4 %) cases. Chronic Chlamydophila pneumoniae infections were seen statistically more often in male patients with carcinoma who were aged 55 years or younger. This study supports the idea that chronic Chlamydophila pneumoniae infection increases the risk of lung carcinoma.

Chlamydia pneumoniae and acute chest syndrome in patients with sickle cell disease

PURPOSE Few studies address the association of Chlamydia pneumoniae infection with pulmonary disease and outcome in patients with underlying pathology such as sickle cell disease (SCD). SCD patients are susceptible to the pulmonary disorder known as acute chest syndrome (ACS), where the etiology remains ill defined. The purpose of this study was to analyze the clinical course and outcome of C. pneumoniae-associated ACS among SCD patients as part of the National Acute Chest Syndrome Study.

PATIENTS AND METHODS

This was a longitudinal study of SCD patients presenting with ACS to multiple U.S. medical centers. Two hundred ninety-six SCD patients who developed ACS were tested by PCR for C. pneumoniae and by standard techniques for other respiratory pathogens. These infections were evaluated for association with ACS, clinical course, and complications.

RESULTS

Forty-one (14%) patients with first episodes of ACS were PCR positive for C. pneumoniae. Compared with other infections, C. pneumoniae-infected patients were older, were more likely to present with chest pain, and had higher hemoglobin levels at diagnosis. Both groups had similar rates of respiratory failure and prolonged hospitalization. Of the 89 patients with single-pathogen infections, 27 (30%) were due to C. pneumoniae, 21% to Mycoplasma pneumoniae, 10% to RSV, 4% to Staphylococcus aureus, and 3% to Streptococcus pneumoniae.

CONCLUSIONS

C. pneumoniae was the most prevalent pathogen in this study of ACS and was responsible for significant morbidity. Additional research is required to develop effective treatment guidelines for ACS.

Seroprevalence of chronic Chlamydia pneumoniae infection in patients affected by chronic stable asthma

OBJECTIVE

To evaluate the seroprevalence of Chlamydia pneumoniae and age, gender and smoking habits in stable asthmatic patients.

METHODS

Over a period of 3 months, 197 adult patients affected by intermittent-to-severe chronic asthma were enrolled from 16 respiratory disease units in the south of Italy. As a control group, we tested 185 healthy, non-asthmatic subjects matched for age and gender, recruited among hospital staff. All patients were submitted to clinical examination, spirometry and blood collection for C. pneumoniae serology. The presence of infection was investigated by microimmunofluorescence (Micro-IF Test) for C. pneumoniae-specific IgG, IgM and IgA antibodies.

RESULTS

C. pneumoniae IgG titers > or =1 : 64 were detected in 30.4% of asthmatics and in 30.8% of controls. Correlation of age, gender and smoking habit with C. pneumoniae seropositivity was evaluated by linear regression analysis. Age was significantly associated with C. pneumoniae IgG titer > or =1 : 64 when seropositive asthmatics were tested. Moreover, C. pneumoniae seroprevalence was higher among smokers with a diagnosis of chronic asthma.

CONCLUSIONS

The seroprevalence of C. pneumoniae in stable asthmatics was comparable with the controls; therefore, the study does not support the association between C. pneumoniae antibody titers and stable asthma. However, the analysis for likely confounders such as age, gender and smoking status suggests a possible association of enhanced susceptibility to C. pneumoniae infection with age and smoking habitus.

Chlamydia pneumoniae seropositivity and the risk of nonarteritic ischemic optic neuropathy

OBJECTIVE

To determine whether IgG antibodies to Chlamydia pneumoniae are associated with nonarteritic ischemic optic neuropathy (NAION).

DESIGN

Retrospective case-control study.

PARTICIPANTS

The study cohort consisted of 71 consecutive patients with NAION and 71 controls matched for age and gender.

MAIN OUTCOME MEASURES

Serum immunoglobulin G (IgG) antibody titers to Chlamydia pneumoniae.

RESULTS

Patients with NAION had significantly higher IgG antibody titers to C. pneumoniae compared with control subjects (IgG titer > or =1:128: 29 patients versus 15 controls, P = 0.017). The odds ratio for patients with an IgG titer > or =1:128 was 2.56 (95% confidence interval [CI], 1.2-5.5). Adjustment for arterial hypertension, diabetes mellitus, and myocardial infarction resulted in an odds ratio of 3.48 (95% CI, 1.3-9.6).

CONCLUSIONS

Our results suggest that elevated titers of IgG antibodies to C. pneumoniae are associated with NAION.

Analysis of Chlamydia pneumoniae growth in cells by reverse transcription-PCR targeted to bacterial gene transcripts

Chlamydia pneumoniae is an obligate intracellular bacterium and has a unique development cycle consisting of an elementary body (EB) and reticular body (RB). EBs survive in extracellular environments as well as infect susceptible host cells. However, EBs display no measurable metabolic activity. In contrast, RBs are metabolically active and can replicate in a host cell but are noninfectious. Therefore, analysis of C. pneumoniae growth in infected cells by conventional bacterial culture may not permit sufficient information about growth of the bacteria in cells. In this study, therefore, we examined the usefulness of the reverse transcription (RT)-PCR method for analysis of bacterial transcripts to evaluate C. pneumoniae growth in HEp-2 cells because the levels of bacterial gene transcripts are known to show the metabolic activity of bacteria. The transcripts for the C. pneumoniae hsp60 gene and 16S rRNA in the cells were easily detected just after infection, followed by a marked increase. In contrast, pyk and omcB transcripts slowly increased after a latent period. The hydrocortisone treatment of C. pneumoniae-infected cells induced an increase of all bacterial transcripts tested compared with the control group. The treatment of the infected cells with the antibiotic minocycline showed a selective inhibition of bacterial gene transcripts, even though the complete inhibition of EB production determined by the bacterial culture assay was evident. These results indicate that the determination of bacterial gene transcripts by RT-PCR might be a powerful method to analyze in detail growth of C. pneumoniae in host cells, particularly altered bacterial growth caused by agents such as antimicrobials.

Detection of Chlamydia pneumoniae antigenin PBMNCs of healthy blood donors

BACKGROUND

Because it has been increasingly recognized that Chlamydia pneumoniae may be linked to some chronic inflammatory diseases, including atherosclerosis, detection of this pathogen in blood from patients may be valuable in the diagnosis of such diseases. However, the prevalence of chlamydia in the blood of healthy donors has not yet been extensively studied.

STUDY DESIGN AND METHODS

The presence of C. pneumoniae in PBMNCs obtained from healthy persons who donated blood for blood transfusion was assessed by a PCR that was specific for the C. pneumoniae 16S rRNA gene and by the use of staining with FITC-conjugated chlamydia MoAb.

RESULTS

Twenty-one (8.9%) of 237 blood samples tested showed the presence of C. pneumoniae DNA and antigen in the PBMNCs. There was no significant difference in the presence of chlamydia in blood according to sex or to age between 20 and 59 years of age. However, a possible seasonal variation in the presence of chlamydia in blood from healthy donors was suggested by the results obtained.

CONCLUSION

A significant percentage of healthy donors carry C. pneumoniae, which may be a risk factor for some chronic diseases.

Chlamydia pneumoniae facilitates monocyte adhesion to endothelial and smooth muscle cells

Chlamydia pneumoniae has been linked to atherosclerotic heart disease. However, there is a limited knowledge by which C. pneumoniae gain access to atheromatous lesions. The adhesion of C. pneumoniae -infected circulatory component(s) to endothelium and smooth muscle cells represents the first step in an inflammatory response. We examined the ability of viable as well as heat inactivated C. pneumoniae to infect human monocytes and subsequently the ability of infected monocytes to adhere to human coronary artery endothelial cells (HCAEC) and human coronary smooth muscle cells (HCSMC). Our results demonstrate susceptibility of monocytes to in vitro chlamydial infection. Inclusions of varying sizes and intensities were observed 3-5 days after inoculation with viable C. pneumoniae. Monocytes infected with heat inactivated organisms revealed no inclusions, in keeping with the observations of uninfected monocytes. Moreover, monocytes infected with viable C. pneumoniae adhered preferentially to HCAEC and HCSMC, as compared to uninfected monocytes or monocytes harbouring heat inactivated Chlamydia.

Detection of Chlamydia pneumoniae DNA in CD3+ lymphocytes from healthy blood donors and patients with coronary artery disease

BACKGROUND

Chlamydia pneumoniae is an intracellular bacterium responsible for respiratory tract infections. Recent studies have implicated this organism in the pathogenesis of atherosclerosis.

METHODS AND RESULTS

To address how the organism is transported from lungs to cardiac vessels, we characterized the cell population within peripheral blood mononuclear cells (PBMCs) that harbor C pneumoniae DNA. Adherent and nonadherent PBMCs from 28 patients with coronary artery disease (CAD) and 19 healthy blood donors were evaluated for the presence of C pneumoniae DNA by touchdown nested polymerase chain reaction (nPCR). Of the 28 patients, 10 (36%) had detectable PCR product in their nonadherent and 3 (10%) in their adherent PBMC population. C pneumoniae-specific PCR results were positive for 5 of 19 (26%) healthy blood donors. PCR positivity was detected only in the nonadherent cell population among this group of individuals. Fractionation of nonadherent PBMCs identified C pneumoniae-specific PCR signal among the CD3+ T-cell population exclusively. Of the 18 PCR-positive subjects (13 patients and 5 healthy control subjects), 67% (8 patients and 4 healthy blood donors) tested positive for C pneumoniae-specific IgG serology. Interestingly, 2 patients became PCR negative on a repeated blood draw 5 months after initial detection of C pneumoniae DNA despite retaining C pneumoniae-specific antibodies.

CONCLUSIONS

Our results demonstrate marginally significant prevalence of C pneumoniae DNA in patients with CAD compared with healthy subjects (P=0.082). In contrast, the prevalence of IgG seropositivity among the 2 groups did not reach statistical significance (P=0.306). We also provide unequivocal evidence for the presence of C pneumoniae DNA predominantly among the circulating CD3+ T-cell population.

Impact of chronic infection with chlamydia pneumoniae on incidence of cardiac allograft vasculopathy

Chronic infection with Chlamydia pneumoniae (CP) is associated with development of coronary disease. However, little information exists concerning CP infection and impact on posttransplant cardiac allograft vasculopathy (CAV). A total of 202 patients were investigated 5.5+/-3.1 years after cardiac transplantation (46.5+/-11.0 years; 169 male, 33 female). Assessment of CAV was performed by annual coronary angiograms. Chlamydia serology (IgG/IgA) was performed using micro-immunofluorescence. Statistics comprised analysis of variance and Kaplan-Meier analysis. A total of 152 patients were CAV positive. Elevated titers were present in 45% (IgG) and 72.8% (IgA) of patients. Generally, serostatus was not associated with development of CAV when evaluated over the total postoperative interval. However, after month 14 there was a significant trend toward lower actuarial freedom from CAV in patients with elevated IgA titers. CP seems not to play a significant role in the development of CAV early after heart transplantation but might be a predicting risk factor after the first postoperative year.

Serologic markers for Chlamydia pneumoniae in asthma

BACKGROUND

Chlamydia pneumoniae infection has been reported as a possible etiologic agent in asthma, which in primary care settings often appears to be initiated by acute respiratory infections.

OBJECTIVE

To determine if serologic markers for C. pneumoniae are associated with adult asthma that first became symptomatic after an acute respiratory illness (asthma associated with infection: AAWI).

METHODS

Serum samples from 164 primary care outpatients, mean age 44 years, (68 with AAWI; 36 with atopic, occupational or exercise-induced asthma (non-AAWI); 16 nonasthmatic patients with acute bronchitis; and 44 asymptomatic nonasthmatic controls) were tested for the presence of C. pneumoniae-specific IgG and IgA antibodies. Levels of chlamydial heat shock protein 60 (CHSP60) antibody were also measured. Those positive for CHSP60 were tested for C. pneumoniae-specific IgE antibodies by immunoblotting.

RESULTS

Statistically significant differences in IgG and IgA seroreactivity were noted between groups: acute bronchitis and AAWI had the highest levels (93% to 94% IgG seroreactivity, 69% to 75% IgA seroreactivity) whereas non-AAWI and asymptomatic controls had the lowest levels (61% to 84% IgG seroreactivity, 31% to 43% IgA seroreactivity, P < .02 after adjustment for age, sex and smoking). CHSP60 antibodies were significantly more prevalent in AAWI than in non-AAWI (19% versus 3%, P = .02). IgE antibodies against C. pneumoniae 60, 62, and/or 70 kD antigens were detected in 5 of 13 CHSP60 positive AAWI patients. Persistent IgG, IgA, and CHSP60 seroreactivities were noted in all seropositive asthma patients with serial serum samples.

CONCLUSIONS

Serologic markers of C. pneumoniae infection were associated with acute bronchitis and with asthma that first became symptomatic following respiratory illness. Serologic responses to C. pneumoniae may be useful in the classification and diagnosis of asthma.

Pneumonia adquirida na comunidade em pacientes tratados ambulatorialmente: aspectos epidemiológicos, clínicos e radiológicos das pneumonias atípicas e não atípicas

Objetivo: Avaliar o percentual etiológico das pneumonias atípicas tratadas ambulatorialmente. Identificar os fatores epidemiológicos, clínicos e radiológicos que permitam diferenciar pneumonia atípica de não atípica. Métodos: Os pacientes foram submetidos a avaliação clínica, radiológica, coleta de escarro para estudo pelo método de Gram e sangue para testes sorológicos, incluindo Legionella pneumophila, Chlamydia sp, Mycoplasma pneumoniae, vírus Influenza A e Influenza B, no primeiro dia e 21 dias após inclusão. As radiografias de tórax foram revistas por três observadores independentes que desconheciam o quadro clínico. Resultados: Avaliados inicialmente 129 pacientes durante 22 meses. A amostra final para estudo comparativo entre os grupos consistiu de 69 pacientes que tinham em média 37 anos, sendo 46 (67%) homens e 23 (33%) mulheres. O diagnóstico etiológico foi definido em 34 (50%) dos pacientes. Chlamydia sp foi o agente atípico mais freqüente, com 11 (16%) casos, seguido por M. pneumoniae com 7 (10%). Influenza A respondeu por 4 (6%) dos casos e Legionella em 4 (6%) pacientes. Infecções mistas foram evidenciadas, com associação de Chlamydia sp e M. pneumoniae em 5 (7%) casos, Chlamydia sp e Influenza B em um caso e M. pneumoniae e Influenza A em outro. A presença de sintomas respiratórios e achados gerais sugestivos de pneumonia atípica foram comparados entre os grupos e não foram observadas diferenças significantes. A avaliação radiológica realizada por três observadores independentes mostrou discordância entre eles para os tipos de pneumonia. O diagnóstico radiográfico de cada observador comparado com o diagnóstico clínico não mostrou associação significante. Conclusões: A pneumonia causada por agente atípico ocorre em 50% dos pacientes com pneumonia adquirida na comunidade em tratamento ambulatorial. Não é possível distinguir pacientes com pneumonia atípica de pneumonia não atípica. A apresentação clínica e a radiológica são similares nos dois grupos.

Chlamydia trachomatis (mouse pneumonitis strain) induces cardiovascular pathology following respiratory tract infection

Chlamydia, especially Chlamydia pneumoniae, infection is closely associated with human cardiovascular diseases. Thus far, however, few experimental studies have been carried out to investigate whether natural C. trachomatis infection can induce cardiovascular pathological changes. In this article, we report that pulmonary infection with C. trachomatis mouse pneumonitis strain (MoPn) can induce myocardial and perivascular inflammation and fibrosis in C57BL/6 mice. The pulmonary MoPn infection appeared to be disseminated systemically, because chlamydial antigens were readily detectable in multiple organs including the cardiovascular tissues. In addition, gamma interferon gene knockout mice with a C57BL/6 genetic background showed significant endocarditis and pancarditis characterized by vegetation in aortic valves, interstitial and pericardial inflammatory cellular infiltration, and growth of the organisms in the heart following respiratory tract MoPn infection. The results indicate that C. trachomatis can induce cardiovascular diseases following respiratory tract infection and suggest that murine MoPn respiratory tract infection may be a useful experimental model for investigating cardiovascular diseases caused by chlamydial infection.

Chlamydia pneumoniae, asthma, and COPD: what is the evidence?

LEARNING OBJECTIVES

Reading this article will familiarize the reader with (1) the unique chlamydial intracellular life cycle and the propensity for human chlamydial infections to become persistent and to result in immunopathologic (inflammatory) damage in target organs and (2) current evidence linking Chlamydia pneumoniae (Cpn) infection to obstructive lung diseases (asthma and chronic obstructive pulmonary disease, COPD). Potential therapeutic implications of the Cpn-asthma association are also discussed.

DATA SOURCES

All Medline articles (January 1985 to March 1999) that cross-referenced the exploded MESH headings "lung diseases, obstructive" and "Chlamydia pneumoniae" (N = 76). Additional referenced articles, published abstracts, book chapters, and conference proceedings were also utilized.

STUDY SELECTION

(1) Case reports and case series that identified Cpn infection in asthma and/or COPD and (2) epidemiologic studies of markers for Cpn infection in asthma and/or COPD that included one or more control groups.

RESULTS

Of 18 controlled epidemiologic studies (over 4000 cases/controls), 15 found significant associations between Cpn infection and asthma using organism detection (polymerase chain reaction (PCR) testing (n = 2 studies) or fluorescent antigen testing (n = 1)), Cpn-specific secretory IgA (sIgA) antibody testing (n = 1), and/or specific serum IgE (n = 2), IgA (n = 4), IgG (n = 3) or other antibody criteria (n = 7). Eight case reports and 13 case series of Cpn infection in asthma (over 100 patients) also include descriptions of improvement or complete disappearance of asthma symptoms after prolonged antibiotic therapy directed against Cpn. Significant associations with COPD (over 1000 cases/controls) were reported in 5 of 6 studies. Results of treating chronic chlamydial infections in COPD patients have not been reported.

CONCLUSIONS

Although the full clinical significance of these Cpn-obstructive lung disease associations remains to be established, reports of asthma improvement after treatment of Cpn infection deserve further investigation. Clinicians who manage asthma should be aware of this information since it may help to manage difficult cases. The hypothesis that Cpn infection in COPD can amplify smoking-associated inflammation and worsen fixed obstruction also deserves further study.

Chlamydia pneumoniae and atherosclerosis

OBJECTIVE

To review the literature for evidence that chronic infection with Chlamydia pneumoniae is associated with atherosclerosis and acute coronary syndromes.

DATA SOURCES

MEDLINE and Institute of Science and Information bibliographic databases were searched at the end of September 1998. Indexing terms used were chlamydi*, heart, coronary, and atherosclerosis. Serological and pathological studies published as papers in any language since 1988 or abstracts since 1997 were selected.

DATA EXTRACTION

It was assumed that chronic C pneumoniae infection is characterised by the presence of both specific IgG and IgA, and serological studies were examined for associations that fulfilled these criteria. Pathological studies were also reviewed for evidence that the presence of C pneumoniae in diseased vessels is associated with the severity and extent of atherosclerosis.

DATA SYNTHESIS

The majority of serological studies have shown an association between C pneumoniae and atherosclerosis. However, the number of cases in studies that have reported a positive association when using strict criteria for chronic infection is similar to the number of cases in studies which found no association. Nevertheless, the organism is widely found in atherosclerotic vessels, although it may not be at all diseased sites and is not confined to the most severe lesions. Rabbit models and preliminary antibiotic trials suggest that the organism might exacerbate atherosclerosis.

CONCLUSION

More evidence is required before C pneumoniae can be accepted as playing a role in atherosclerosis. Although use of antibiotics in routine practice is not justified, large scale trials in progress will help to elucidate the role of C pneumoniae.

Prevalence of specific antibodies to Chlamydia pneumoniae in Korea

To clarify the endemic status of Chlamydia pneumoniae in Korea, the incidence of antibodies in 564 serum samples from healthy individuals, patients with respiratory infection, and cord blood specimens was evaluated. We conclude that C. pneumoniae infection is highly endemic in Korea and that this infection is associated with acute respiratory diseases.

Chlamydia pneumoniae infection in patients with diffuse panbronchiolitis and COPD

STUDY OBJECTIVES

To determine the possible association of Chlamydia pneumoniae infection with diffuse panbronchiolitis (DPB) and with COPD.

DESIGN

Prospective case-control study.

SETTING

Division of Respiratory Diseases, Kawasaki Medical School Hospital.

PARTICIPANTS

Fifteen DPB and 77 COPD patients who had acute exacerbations of respiratory conditions and 35 and 120 control subjects, respectively, matched for age, sex, and smoking status.

MEASUREMENTS AND RESULTS

Nasopharyngeal swabs and paired serum samples were obtained from all patients and control subjects for isolation and antibody testing of C pneumoniae. C pneumoniae was isolated from one DPB patient and from no COPD patients or control subjects. Serologic evidence of acute C pneumoniae infection was observed in one DPB patient (6.7%) and six COPD patients (7.8%). The prevalence and mean titer of C pneumoniae IgG and IgA antibodies were significantly higher in COPD patients than in control subjects (p<0.001). However, no such differences were observed between DPB patients and control subjects.

CONCLUSIONS

This study showed that C pneumoniae infection may be associated with acute exacerbations of COPD and that chronic C pneumoniae infection is common in COPD but not in DPB.

Prevalence of Chlamydia pneumoniae specific antibodies in different clinical situations and healthy subjects in Izmir, Turkey

Serological markers for Chlamydia pneumoniae were investigated by using the microimmunofluorescence (MIF) test in various age and patient groups in a specific area in Turkey. IgG seropositivity to C. pneumoniae was 64.3% and 18.7% in healthy adults and children, respectively. The highest positivity rate (77%) was in the 15-19 age group. Among the groups investigated, serological findings revealed a possible etiological association between C. pneumoniae and the clinical condition in the groups with acute myocardial infarction, atypical pneumoniae and chronic obstructive pulmonary disease.

Chlamydia pneumoniae and exacerbations of asthma in adults

BACKGROUND

Chlamydia pneumoniae is a frequent causative agent of acute respiratory disease and has been recently reported as a possible cause of asthma.

OBJECTIVE

We assessed the prevalence of C. pneumoniae infections in adult patients with acute exacerbations of asthma.

METHODS

One hundred sixty-eight adult patients with acute exacerbations of asthma and 108 control subjects matched for age, sex, and smoking status were studied. Nasopharyngeal swab specimens were obtained from all subjects and analyzed by isolation in cell culture and polymerase chain reaction (PCR) test for C. pneumoniae. Serum samples were also obtained and tested for C. pneumoniae-specific antibodies by the microimmunofluorescence test.

RESULTS

C. pneumoniae was isolated from two (1.2%) asthma patients and none from controls and detected by PCR from nine (5.4%) cases and one (0.9%) control. Both culture positive specimens were also positive in PCR. Further, serologic evidence of acute C. pneumoniae infection was present in 15 (8.9%) of asthma patients and in three (2.8%) of controls (P = .048). The prevalence of C. pneumoniae-specific IgG and IgA was significantly higher in asthma cases than in controls (IgG > or = 1:16: 85.1% versus 67.6%, P = .001; IgA > or = 1:16: 47.6% versus 16.7%, P < .001). Mean titer of IgG and IgA was also significantly greater in asthma cases than in controls (IgG: 38.8 versus 18.1, P = .0001; IgA: 17.2 versus 6.1, P = .0001).

CONCLUSIONS

Our data suggest that C. pneumoniae infection may trigger acute exacerbations of adult asthma.

Chlamydia pneumoniae and its role in chronic obstructive pulmonary disease

The diverging of T-helper (Th) cells into predominantly Th1 and Th2 subsets on the basis of their cytokine profiles has decisively improved our understanding of the pathogenesis of many chronic infectious diseases. Recent data suggest that the presence of interferon-gamma and the subsequent suppression of interleukin-4 production leads to a Th1-type response that is required for the resolution of infections caused by intracellular pathogens. The ability of the macrophages to respond aggressively during early antigen contact seems to be one crucial factor in the development of an appropriate Th-cell response. Several host-related factors can affect macrophage function and the polarization of T-cell responses, ie the shift from a Th1 response to a Th2 one, and thus dramatically deteriorate the resolution of infections caused by intracellular agents such as Chlamydia pneumoniae. Chronic C. pneumoniae infection has been associated with several common chronic diseases, quite recently with chronic obstructive pulmonary disease. Chronic C. pneumoniae infection may amplify smoking-associated inflammation in the bronchi and may be a contributory factor in the development of irreversible pathological changes.

Evidence for Chlamydia pneumoniae infection in steroid-dependent asthma

BACKGROUND

Chlamydia pneumoniae is an obligate intracellular respiratory pathogen capable of persistent infection. Seroepidemiologic studies and the results of open-label antimicrobial treatment of patients with non-steroid-dependent asthma have suggested a potential role for C. pneumoniae in asthma.

OBJECTIVE

To evaluate the results of antimicrobial treatment in patients with uncontrolled steroid-dependent asthma and serologic evidence suggesting C. pneumoniae infection.

METHODS

Three nonsmoking asthmatic patients (aged 13 to 65 years) whose symptoms remained poorly controlled despite daily administration of inhaled and oral steroid (10 to 40 mg/d). All met serologic criteria for current or recent C. pneumoniae infection.

RESULTS

After prolonged treatment (6 to 16 weeks) with clarithromycin or azithromycin all three patients were able to discontinue oral steroids. All three patients have remained well controlled with inhaled antiasthma therapy only during 3 to 24 months of postantibiotic therapy observation.

CONCLUSIONS

In adolescent and adult asthmatic patients, Chlamydia pneumoniae infection may contribute to symptoms of asthma that are poorly controlled by steroids. Serologic evidence for C. pneumoniae infection should be sought in such patients. A trial of appropriate antibiotic therapy may be helpful in those patients with high titers of anti-C. pneumoniae IgG antibodies.

Mediastinal lymphadenitis associated with Chlamydia pneumoniae infection

A young woman presented with mediastinal lymphadenitis and measles-like eruption. All clinical manifestations promptly responded to macrolide therapy. Serologically, current infection of Chlamydia pneumoniae was highly suspected. Evaluation of Chlamydia pneumoniae infection should be included in the diagnostic approach to mediastinal lymphadenitis.

LOWER RESPIRATORY TRACT INFECTIONS IN ELDERLY PATIENTS WITH ASTHMA

Infection plays a significant role in the morbidity and mortality of the elderly. One population in which infection has not been adequately studied is the elderly asthmatic. This article examines the problems of lower respiratory tract infections in elderly asthmatics in the context of their host defenses, the severity of infection, and their risk of infection with specific organisms. The role of infection in the pathogenesis of asthma and consideration of prophylaxis and therapy are presented.

Chlamydia pneumoniae respiratory infections among patients infected with the human immunodeficiency virus

Thirteen cases of Chlamydia pneumoniae infection in patients seropositive for the human immunodeficiency virus (HIV) are described. The occurrence, the clinical spectrum, and the significance of the infection during HIV disease are compared with data reported in the literature. Chlamydia pneumoniae infection was established by a serologic micro-immunofluorescence test using standard diagnostic criteria. In four cases the results of serological tests were confirmed by direct immunofluorescence on respiratory specimens. Five patients developed focal pneumonia but recovered completely after specific antibiotic treatment. Three patients developed severe and diffuse interstitial pulmonary involvement, two of whom died of acute respiratory failure. Five patients developed upper respiratory tract infection. Using 39 pair-matched HIV-seropositive subjects as controls, the cases of infection were found to be significantly associated with a previously diagnosed pulmonary disease. Upon retrospective analysis of 319 consecutive cases of pneumonia among HIV-infected patients, Chlamydia pneumoniae was the sole agent detected in eight (2.5%) cases, and Chlamydia pneumoniae together with other infectious agents was detected in seven (2.2%) cases. Chlamydia pneumoniae is a possible cause of severe respiratory infection in Italian HIV-infected immunocompromised patients, and its presence must be suspected when patients do not respond to therapy with beta-lactam agents or to anti-Pneumocystis carinii treatment.

Exposures to Legionella pneumophila and Chlamydia pneumoniae in South African Mine Workers

Exposures of South African mine workers to Legionella pneumophila and Chlamydia pneumoniae were studied over a period of six months. Seroprevalence data were compared with data from a group of factory workers. Antibodies to L. pneumophila serogroups 1-4 were demonstrated in 36% of the mine workers and 10% of the factory workers (p < 0.0001). Seroconversion occurred in 18% of the mine workers during the study period. Antibodies to C. pneumoniae were present in 66% of the mine workers and 22% of the factory workers (p < 0.0001). Seroconversion was demonstrated in 17% of the mine workers during the six months of follow-up. A significant association between the presence of respiratory symptoms and seroconversion was demonstrated (p < 0.025). The data suggest that mine workers are at increased risk for infections with L. pneumophila and C. pneumoniae. Legionella pneumophila; Chlamydia pneumoniae; mine workers; factory workers; risk factors; seroprevalence; seroconversion

Chlamydia pneumoniae: a new opportunistic infectious agent in AIDS?

OBJECTIVE: To determine the incidence of Chlamydia pneumoniae respiratory tract infection in HIV-positive or AIDS patients. METHODS: Serum samples from 82 HIV-positive patients with fever and respiratory symptoms were evaluated using microimmunofluorescence assay to detect C. pneumoniae-specific IgG and IgM antibodies. RESULTS: Twenty patients were found to have IgG antibodies to C. pneumoniae at titers ranging between 1:16 and 1:1024. Seven of the patients had evidence of acute C. pneumoniae infection (a fourfold rise in the titer of IgG antibody, or a single IgG titer of greater-than-or-equal1:512, or a single IgM titer greater-than-or-equal1:16). Five were diagnosed as having pneumonia and two bronchitis. No co-infection with other respiratory tract pathogens was found. CONCLUSIONS: Results of this study indicate that C. pneumoniae may play a role in the etiology of respiratory tract infections in HIV-positive patients; this fact should affect empirical antibiotic prescription.

Community-acquired pneumonia in older patients

OBJECTIVES

To document the prevalence of Legionella sp., Mycoplasma Pneumoniae and Influenza A and B in older patients hospitalized for community-acquired pneumonia (CAP) of nursing-home acquired pneumonia (NHAP) and to determine risk factors associated with fatal outcome or prolonged hospital stay.

DESIGN

Prospective clinical and serological study.

PATIENTS

All patients with CAP of NHAP--confirmed by chest roentgenogram--admitted to a 320-bed acute care geriatric university hospital from May 1, 1988 to August 31, 1989, were included. Serological testing was performed upon admission and after 2 and 4 weeks. Relevant data concerning medical history, clinical examination, and laboratory data were recorded upon admission. Ninety-nine patients (age: 85 +/- 6.3 years, 36 male, 63 female) met inclusion criteria; 20 came from nursing homes, 79 from their homes in the community.

MAIN RESULTS

Fourteen patients died during the month after admission. An etiological diagnosis could be established in 22 patients. No cases of Legionella pneumonia and one case of M. pneumoniae were detected. Seven patients had evidence of Influenza pneumonia. Nonsurvivors were more likely to have been admitted from a nursing home and to have a temperature less than 37.5 degrees C and elevated urea nitrogen (BUN). Cyanosis, involvement of upper lobes, elevated white blood cell counts, and higher percentage of band forms were associated statistically with longer treatment.

CONCLUSIONS

This study confirms the low prevalence of Legionella sp. and M. Pneumoniae infection in CAP and NHAP in this age group. Risk factors as to outcome and length of treatment may be used as points to identify high risk patients, with special attention to patients coming from nursing homes, and patients with high BUN.