Clinical picture of community-acquired Chlamydia pneumoniae pneumonia requiring hospital treatment: a comparison between chlamydial and pneumococcal pneumonia

Epidemiological changes in Chlamydia pneumoniae molecular detections before, during and after the COVID-19 pandemic in 27 European sites and Taiwan, 2018 to 2023

BackgroundDuring the COVID-19 pandemic, non-pharmaceutical interventions (NPIs) such as social distancing, lockdowns and enhanced hygiene led to a decrease in respiratory pathogens. However, as NPIs were relaxed, a resurgence in several respiratory pathogens was observed including one local Chlamydia pneumoniae outbreak in Switzerland, prompting the need for a better understanding of C. pneumoniae epidemiology.AimTo assess temporal and geographical variations in C. pneumoniae detection before, during and after the COVID-19 pandemic.MethodsData on C. pneumoniae PCR detection ratios (number of positive tests/ total number of tests) across pre-pandemic (2018-2019), pandemic (2020-2022) and post-pandemic (2023) periods were collected via a global survey disseminated through various professional networks.ResultsC. pneumoniae detection ratios were analysed across 28 sites (27 in Europe, one in Taiwan) in 2023 (Dataset A, n = 172,223 tests) and 20 sites from 2018 to 2023 (Dataset B, n = 693,106 tests). Twenty-seven sites were laboratories (hospital or clinical) and one a surveillance system (Denmark). A significant decrease in detection ratios was observed during the pandemic period (from 1.05% to 0.23%, p < 0.001). In 2023, detection ratios increased to 0.28% (p < 0.002). Notable regional variations were found, with statistically significant increases in detection ratios at six sites located in Switzerland and Slovenia, where ratios ranged from 0.52% to 3.25%.DiscussionThe study highlights how NPIs influenced C. pneumoniae epidemiology, with reduced detection during the pandemic and partial resurgence afterwards. Regional variations suggest differing NPI impacts and underscore the need for continued surveillance.

From coughs to complications: the story of Chlamydia pneumoniae

Chlamydia pneumoniae is an obligate intracellular bacterium and a significant cause of respiratory infections. It is associated with upper and lower respiratory tract diseases, including bronchitis and pneumonia. The pathogen employs specific virulence factors, such as the Type III Secretion System (T3SS) and Inc proteins, to invade and subvert host cell machinery during its peculiar developmental life cycle. Chronic infections have been linked to asthma and, more controversially, to atherosclerosis and neurodegenerative diseases. Diagnosis primarily relies on PCR-based molecular assays, while treatment includes macrolides, tetracyclines or fluoroquinolones. Despite its clinical relevance, research on C. pneumoniae has declined in recent years, highlighting the need for renewed scientific focus.

Headache in the presentation of noncephalic acute illness

Background:

Headache is a frequent symptom of many systemic diseases that do not involve cranial structures. In this observational study, we assessed factors associated with headache in the acute presentation of systemic conditions in a nonsurgical emergency department (ED).

Methods:

Consecutive patients, admitted to Soroka University Medical Center ED due to noncephalic illness, were prospectively surveyed using a structured questionnaire focused on the prevalence and characteristics of headache symptoms. Medical data were extracted from the patient's charts.

Results:

Between 1 and 6/2012, 194 patients aged 64.69 ± 19.52 years, were evaluated. Headache was reported by 83 (42.7%) patients and was more common among patients with febrile illness (77.5% vs. 22.5%, P < 0.001). Respiratory illness and level of O₂ saturation were not associated with headache. Headache in the presentation of a noncephalic illness was associated with younger age (58 vs. 69, P < 0.001) and with suffering from a primary headache disorder (48.2% vs. 10.8%, P < 0.001). Headache was also associated with higher body temperature and lower platelets count.

Conclusions:

Headache is a common symptom in acute noncephalic conditions and was found to be associated with younger age and febrile disease on presentation. Patients who present with primary headache disorders are more prone to have headache during acute illness. Acute obstructive respiratory disease, hypercarbia or hypoxemia were not associated with headache.

Evolution to a chronic disease niche correlates with increased sensitivity to tryptophan availability for the obligate intracellular bacterium Chlamydia pneumoniae

The chlamydiae are obligate intracellular parasites that have evolved specific interactions with their various hosts and host cell types to ensure their successful survival and consequential pathogenesis. The species Chlamydia pneumoniae is ubiquitous, with serological studies showing that most humans are infected at some stage in their lifetime. While most human infections are asymptomatic, C. pneumoniae can cause more-severe respiratory disease and pneumonia and has been linked to chronic diseases such as asthma, atherosclerosis, and even Alzheimer's disease. The widely dispersed animal-adapted C. pneumoniae strains cause an equally wide range of diseases in their hosts. It is emerging that the ability of C. pneumoniae to survive inside its target cells, including evasion of the host's immune attack mechanisms, is linked to the acquisition of key metabolites. Tryptophan and arginine are key checkpoint compounds in this host-parasite battle. Interestingly, the animal strains of C. pneumoniae have a slightly larger genome, enabling them to cope better with metabolite restrictions. It therefore appears that as the evolutionarily more ancient animal strains have evolved to infect humans, they have selectively become more "susceptible" to the levels of key metabolites, such as tryptophan. While this might initially appear to be a weakness, it allows these human C. pneumoniae strains to exquisitely sense host immune attack and respond by rapidly reverting to a persistent phase. During persistence, they reduce their metabolic levels, halting progression of their developmental cycle, waiting until the hostile external conditions have passed before they reemerge.

Respiratory viral and pneumococcal coinfection of the respiratory tract: implications of pneumococcal vaccination

The interactions between Streptococcus pneumoniae and other respiratory pathogens have been studied in vitro, in animal models and in humans - including epidemiologic and vaccine probe studies. Interactions of pneumococcus with respiratory viruses are common, and many mechanisms have been suggested to explain this phenomenon. The aim of this review is to explore pneumococcal interactions with respiratory viruses and consider the potential role that the pneumococcal polysaccharide-protein conjugate vaccine may play in modifying pneumococcal-respiratory viral interactions.

Chlamydophila pneumoniae

Chlamydophila pneumoniae is estimated to cause about 10% of community-acquired pneumonia (CAP) cases and 5% of bronchitis cases, although most patients with C pneumoniae infection are asymptomatic, and the course of respiratory illness is relatively mild. The incubation period of C pneumoniae infection is around 21 days, and such symptoms as cough and malaise show a gradual onset, yet may persist for several weeks or months despite appropriate antibiotic therapy. Diagnosis by nasopharyngeal specimen culture, serum antibody titers, or molecular techniques is usually delayed with respect to the onset of symptoms, antibiotic treatment, or disease resolution and there is no accurate, standardized, commercial US Food and Drug Administration-cleared diagnostic method available. Erythromycin, tetracycline, and doxycycline are used as first-line therapy, although some investigators report no clinical or survival benefits from treating CAP caused by atypical pathogens. Meanwhile, adequate prospective studies have met with ethical and logistic barriers. Despite these limitations, North American guidelines recommend the antimicrobial treatment of patients with acute C pneumoniae respiratory infection.

Treatment failure in community-acquired pneumonia

Treatment failure (TF) is defined as a clinical condition with inadequate response to antimicrobial therapy. Clinical response should be evaluated within the first 72 h of treatment, whereas infiltrate images may take up to 6 weeks to resolve. Early failure is considered when ventilatory support and/or septic shock appear within the first 72 h. The incidence of treatment failure in community-acquired pneumonia is 10 to 15%, and the mortality is increased nearly fivefold. Resistant and unusual microorganisms and noninfectious causes are responsible for TF. Risk factors are related to the initial severity of the disease, the presence of comorbidity, the microorganism involved, and the antimicrobial treatment implemented. Characteristics of patients and factors related to inflammatory response have been associated with delayed resolution and poor prognosis. The diagnostic approach to TF depends on the degree of clinical impact, host factors, and the possible cause. Initial reevaluation should include a confirmation of the diagnosis of pneumonia, noninvasive microbiological samples, and new radiographic studies. A conservative approach of clinical monitoring and serial radiographs may be recommended in elderly patients with comorbid conditions that justify a delayed response. Invasive studies with bronchoscopy to obtain protected brush specimen and BAL are indicated in the presence of clinical deterioration or failure to stabilize. BAL processing should include the study of cell patterns to rule out other noninfectious diseases and complete microbiological studies. The diagnostic yield of imaging procedures with noninvasive and invasive samples is up to 70%. After obtaining microbiological samples, an empirical change in antibiotic therapy is required to cover a wider microbial spectrum.

Severe community-acquired pneumonia: approach to therapy

Despite substantial progress in therapeutic options, severe community-acquired pneumonia (CAP) remains a significant cause of morbidity and mortality worldwide. Recognising the clinical importance of CAP over the past several years, different medical societies and health organisations in different countries have proposed specific guidelines for the management of CAP. Early and rapid initiation of antimicrobial therapy has been advocated for a favourable outcome. Treatment is empirical as the diagnostic yield for potential pathogens does not exceed 50%. Dual therapy is emerging as the preferred therapy for severe CAP. The regimen is based on an epidemiological approach with emphasis on covering both typical and atypical pathogens. Non-antimicrobial adjuvant therapies including non-invasive ventilation and immunomodulatory agents are emerging as promising area for future development.

Pulmonary tuberculosis presenting as community-acquired pneumonia

OBJECTIVE AND BACKGROUND

The aims of this study were to investigate the frequency of Mycobacterium tuberculosis as a cause of community-acquired pneumonia (CAP) requiring hospitalization in Malaysia, and to define the clinical features of pulmonary tuberculosis (PTB) that distinguish it from non-TB CAP.

METHODS

A prospective study was performed on consecutive non-immunocompromised patients aged 12 years and older, who were hospitalized for CAP.

RESULTS

Of a total of 346 patients hospitalized for CAP, the aetiological agent was identified in 163 patients (47.1%). M. tuberculosis was isolated in 17 patients (4.9%). Multivariate analysis revealed that the following features were significantly associated with culture-positive PTB: duration of symptoms of more than 2 weeks before hospital admission (odds ratio (OR) 25.10; 95% confidence interval (CI) 4.63-136.05; P<0.001), history of night sweats (OR 5.43; 95% CI 1.10-26.79; P=0.038), chest radiograph showing upper lobe involvement (OR 8.23; 95% CI 1.59-42.53; P=0.012) or cavitary infiltrates (OR 19.41; 95% CI 2.94-128.19; P=0.002), total white blood cell count on admission of 12x10(9)/L or less (OR 6.28; 95% CI 1.21-32.52; P=0.029) and lymphopenia (OR 4.73; 95% CI 1.08-20.85; P=0.040).

CONCLUSION

Mycobacterium tuberculosis was not an uncommon cause of CAP requiring hospitalization in Malaysia. A longer duration of symptoms, history of night sweats, upper lobe involvement, cavitary infiltrates, lower total white blood cell count and lymphopenia were predictive of PTB.

13 – Antibiotic therapy of community-acquired pneumonia (CAP) caused by atypical agents

Macrolides, fluoroquinolones, doxycycline, and ketolides show a good intrinsic activity against intracellular pathogens which are responsible for a variable percentage of community-acquired pneumonia (CAP). These therapeutic agents all seem effective in treating most cases of CAP caused by Mycoplasma pneumoniae, Chlamydia pneumoniae, or Legionella spp. Among quinolones, the more recent fluoroquinolones, such as gemifloxacin or moxifloxacin, generally show a better intrinsic activity than the older ones. Among macrolides, azithromycin, and clarithromycin show a better pharmacokinetic profile. Both of them are available in intravenous form. It is quite common for M. pneumoniae and C. pneumoniae to continue to be shed in respiratory secretions, weeks after an effective therapy. The clinical relevance of this finding is not clear since most of these patients have a good outcome. Azithromycin, due to its advantageous pharmacokinetic profile, seems the best option when antibiotic prophylaxis is considered in some epidemiological settings. It has been proved effective in closed M. pneumoniae outbreaks.

Approaches to treatment of community-acquired pneumonia in the emergency department and the appropriate role of fluoroquinolones

The Emergency Department is a critical point of care for patients presenting with signs and symptoms of community-acquired pneumonia (CAP). The initial diagnosis, the decision to admit or discharge, the timing of initiating treatment, and appropriateness of the empirical therapy are key factors in successful management. Rising resistance rates to commonly used CAP antibiotics has complicated empirical treatment. Respiratory fluoroquinolones represent an important therapeutic option for patients with co-morbidities and risk factors for penicillin-, macrolide-, and multi-drug-resistant S. pneumoniae infections. Ensuring appropriate use is required to maintain their high level of effectiveness in key respiratory pathogens. Treatment guidelines from the Infectious Diseases Society of America, American Thoracic Society, and Centers for Disease Control and Prevention are available to assist emergency physicians in developing clinical pathways to ensure appropriate use of available therapies.

Challenges in the management of community-acquired pneumonia: the role of quinolones and moxifloxacin

Current strategies and guidelines for the treatment of community-acquired pneumonia are directed toward making care cost effective, by treating patients on an outpatient basis whenever possible. The use of the new fluoroquinolones could help to achieve these goals. These agents are highly bioavailable and can facilitate the oral treatment of certain patients who otherwise might be admitted to the hospital, as outpatients. The good absorption and bioavailability of these agents can allow moderately ill patients to rapidly achieve effective serum levels of the drug after oral administration and can also facilitate early discontinuation of intravenous therapy and early discharge for responding inpatients. For inpatients or outpatients with clinical risk factors for acquiring drug-resistant pneumococci, quinolones represent a reliable monotherapy option and an effective alternative to a beta-lactam/macrolide combination. Although the in vitro differences among the various quinolones remain of unclear clinical relevance, preliminary data suggest that agents with enhanced in vitro activity against pneumococci, such as moxifloxacin, may have greater clinical efficacy and may lead to more-rapid resolution of fever and, potentially, less selection of future pneumococcal resistance to quinolones than that associated with agents with less intrinsic activity.

Low prevalence of Chlamydia pneumoniae in adults with community-acquired pneumonia

The incidence of community-acquired pneumonia (CAP) due to Chlamydia pneumoniae was determined in a prospective study of 546 adult patients with CAP included in the German CAP Competence Network (CAPNETZ) project. Three different PCR protocols for detection of C. pneumoniae in respiratory specimens were compared by a multicenter, inter-laboratory comparison involving three laboratories. A case was defined as a patient with a respiratory sample positive by PCR in at least two laboratories. CAP was caused by C. pneumoniae in 5/546 cases (0.9%). Antibody testing by microimmunofluorescence was done in 376 of 546 patients. All patients were negative for IgM antibodies. In the five PCR-positive patients, neither specific IgG nor IgA antibodies were found. Patients with CAP caused by C. pneumoniae had a lower median age (36 years) than the general study population (62 years). C. pneumoniae is currently a rare cause of CAP in adult patients in Germany. Analysis of a single serum sample is not useful for diagnosis of acute C. pneumoniae infection in CAP.

Community epidemiology of Chlamydia and Mycoplasma pneumoniae in LRTI in France over 29 months

BACKGROUND

The role of Chlamydia pneumoniae (CP) and Mycoplasma pneumoniae (MP) in lower respiratory tract infections (LRTI) is still little known in community settings.

METHODS

In all, 3207 adult cases of LRTI (871 with pneumonia, and 2336 with acute bronchitis) were prospectively included in the ETIIC1 ETIIC : ETude de l'Incidence des Infections respiratoires basses d'origine Communautaire dues A Chlamydia pneumoniae et Mycoplasma pneumoniae (Incidence of CP and MP in LRTI in community settings) program by 303 general practitioners and 24 hospital physicians in France between September 1997 and February 2000. The polymerase chain reaction and immunoassays were used to detect CP or MP in 3198 pharyngeal specimens obtained by gargling.

RESULTS

Of these 3198 patients, 232 (7.3%), were PCR-positive for CP and/or MP. Immunoassays were far less sensitive than PCRs (Se = 2 and 13% for MP and CP). Among the 2336 patients with acute bronchitis, PCR was positive for CP in 95 (4.1%), and for MP, in 54 (2.3%). Among the 671 patients with radiologically confirmed pneumonia, PCR was positive for CP in 23 (3.4%), and for MP in 49 (7.3%). CP and MP displayed significant geographic heterogeneity. Independent clinical determinants of positive PCR for CP and/or MP were age below 45 years, previous antimicrobial therapy (especially betalactams). Clinical signs were not of practical use in distinguishing accurately between etiologic diagnoses.

CONCLUSIONS

CP or MP diagnosed by PCR were found in more than 7% of patients with LRTI in community settings with a significant geographical heterogeneity and significant temporal trends in the incidence.

Prospective multicenter study of the causative organisms of community-acquired pneumonia in adults in Japan

Although a wide variety of recognized pathogens causes community-acquired pneumonia, the precise etiology in Japan remains unknown. We prospectively investigated the etiology in 232 patients with community-acquired pneumonia who visited 20 community-general hospitals. New diagnostic methods, using polymerase chain reaction (PCR) assays and urinary antigen tests were employed, in addition to conventional methods. The frequency of identification of causative pathogens was high (73.3%), and the leading organism was Streptococcus pneumoniae (24.6%), followed by Haemophilus influenzae (18.5%), viruses (16.4%), Chlamydia pneumoniae (6.5%), Mycoplasma pneumoniae (5.2%), and Legionella spp. (3.9%). S. pneumoniae and M. pneumoniae were the most prevalent pathogens in younger patients, and S. pneumoniae and H. influenzae were the most prevalent in elderly patients. Multiple or mixed infections were found in 25.9% of all patients and in 35.3% with a causal diagnosis. The results have important practical implications for the initial treatment of adult patients with community-acquired pneumonia.

Therapeutic approaches toChlamydiainfections

Chlamydia trachomatis ocular and urogenital infections represent major public health problems, whereas Chlamydophila pneumoniae is a common aetiological agent of community-acquired pneumonia. The obligate intracellular lifestyle of these established pathogens poses challenges to both their diagnosis and treatment. Tetracyclines, macrolides and quinolones remain the antimicrobials of choice for the treatment of infections due to Chlamydiaceae.

Chlamydia pneumoniae Pneumonia and Mycoplasma pneumoniae Pneumonia

The objective of this study was to identify the clinical and pulmonary CT findings associated with Chlamydia pneumoniae pneumonia and to compare them with those of Mycoplasma pneumoniae pneumonia. The clinical features and CT scans of 40 patients with C. pneumoniae pneumonia and 42 patients with M. pneumoniae pneumonia were retrospectively reviewed. There were no significant differences between the two etiologic agents with regard to clinical signs. Chest CT findings in patients with C. pneumoniae pneumonia consisted mainly of ground-glass attenuation (n = 38) and acinar patterns (n = 28). Acinar patterns and pleural effusions (n = 12) were observed significantly more frequently than in patients with M. pneumoniae pneumonia (P < 0.0001, P < 0.039, respectively). CT findings of centrilobular nodules and bronchial wall thickening were significantly less common than in the M. pneumoniae pneumonia patients (P < 0.0001, P < 0.0001, respectively). The CT finding of acinar patterns, although nonspecific, can be considered suggestive of C. pneumoniae pneumonia.

Self-limiting pneumonia due to Chlamydia pneumoniae

A case of self-limiting pneumonia due to Chlamydia pneumoniae is described. A 39-year-old male visited our hospital complaining of a persistent cough. No antibiotics were administered to this patient because of the absence of fever and a mild positive inflammatory response, but an infiltrate on a chest radiograph improved. Finally, a diagnosis of C. pneumoniae pneumonia was made by seroconversion of the C. pneumoniae-specific antibody and detection of the C. pneumoniae gene in bronchoalveolar lavage fluid. Self-limiting C. pneumoniae pneumonia is rarely encountered, although self-limiting upper respiratory tract infections due to C. pneumoniae are common. Thus, most self-limiting C. pneumoniae pneumonia may be missed when symptoms are minimal.

Appropriate Outpatient Macrolide Use in Community‐Acquired Pneumonia

PURPOSE

To review current guidelines concerning the outpatient management of community-acquired pneumonia (CAP), to discuss antibiotic resistance and its relation to outcomes, and to define the appropriate use of newer macrolides in CAP.

DATA SOURCES

Comprehensive review of the scientific literature, comparison of published clinical practice guidelines, and expert opinion.

CONCLUSIONS

Despite increasing knowledge regarding its etiology and pathogenesis, CAP remains the seventh leading cause of death in the United States. Although 80% of all patients with CAP are treated as outpatients, over 1 million hospital admissions due to CAP occur each year. From an employer perspective, total annual employer costs were fivefold greater for patients with pneumonia than for those who were not affected. Appropriate antimicrobial choices should lead to improved outcomes. Reports of increasing resistance of pathogens associated with CAP, increasing frequency of atypical pathogens, and the availability of an increasing number of antimicrobials have made treatment decisions more involved.

IMPLICATIONS FOR PRACTICE

In an effort to improve outcomes, several guidelines have been published recommending appropriate antimicrobial agents to treat CAP in different patient populations. All guidelines base treatment recommendations on the hospitalization status of the patient, and all agree that coverage of atypical pathogens as part of an initial empirical regimen is important. Comorbidity and modifying factors that may increase the risk of infection with resistant organisms also are taken into account. Controversy exists regarding the use of newer macrolides versus newer fluoroquinolones as initial empirical therapy. The applicability of the reported increasing resistance of common pneumonia pathogens to outcomes in regimens containing newer macrolides is a subject of debate. Defining appropriate antimicrobial use in different patient groups should help achieve better outcomes and allay the development of resistance.

Microbiological profile of community-acquired pneumonia in adults over the last 20 years

OBJECTIVES

To assess any change in the microbiological profile of community-acquired pneumonia (CAP) in our region over the last 20 years.

METHODS

We compared hospital admissions aged between 15 and 74 (n = 61) in Norfolk (UK) for CAP over a 19-month period in 1982-3 (ST1) with all admissions aged over 16 (n = 99) over a 14-month period in 1999-2000 (ST2). Data were collected for ST1 as part of a prospective multicentred research study, in a period of high Mycoplasma pneumoniae activity. ST2 was a prospective study of clinical practice. Chlamydophila species were differentiated in ST2 using whole-cell immunofluorescence.

RESULTS

A microbiological diagnosis was made in 38 (62%) in ST1 compared with 48 (48%) in ST2. Streptococcus pneumoniae remained the most common pathogen (26% in ST1, 25% in ST2). The incidence of M. pneumoniae was 18% in ST1 and 4% in ST2. The proportion of viral pathogens identified was similar: nine (15%) in ST1 and 14 (14%) in ST2. No cases of Chlamydophila pneumoniae were diagnosed in ST2.

CONCLUSIONS

The microbiological profile of CAP in Norfolk (UK) has not changed over the last 20 years and C. pneumoniae is not a frequent pathogen.

Nonresolving Pneumonia

Uncertainty over the expected clinical course of a community-acquired or nosocomial pneumonia is a common reason for pulmonary consultation. Determining which patients with prolonged pneumonia and at what point during therapy they should undergo further evaluation can be challenging. This article reviews "normal" resolution times for the most common pneumonias, risk factors for delayed resolution, and infectious and noninfectious conditions that can cause nonresolving pneumonia. An approach to the evaluation of the patient with this common problem is described.

Effectiveness of beta lactam antibiotics compared with antibiotics active against atypical pathogens in non-severe community acquired pneumonia: meta-analysis

OBJECTIVE

To systematically compare beta lactam antibiotics with antibiotics active against atypical pathogens in the management of community acquired pneumonia.

DATA SOURCES

Medline, Embase, Cochrane register of controlled trials, international conference proceedings, drug registration authorities, and pharmaceutical companies. Review methods Double blind randomised controlled monotherapy trials comparing beta lactam antibiotics with antibiotics active against atypical pathogens in adults with community acquired pneumonia. Primary outcome was failure to achieve clinical cure or improvement.

RESULTS

18 trials totalling 6749 participants were identified, with most patients having mild to moderate community acquired pneumonia. The summary relative risk for treatment failure in all cause community acquired pneumonia showed no advantage of antibiotics active against atypical pathogens over beta lactam antibiotics (0.97, 95% confidence interval 0.87 to 1.07). Subgroup analysis was undertaken in those with a specific diagnosis involving atypical pathogens. We found a significantly lower failure rate in patients with Legionella species who were treated with antibiotics active against atypical pathogens (0.40, 0.19 to 0.85). Equivalence was seen for Mycoplasma pneumoniae (0.60, 0.31 to 1.17) and Chlamydia pneumoniae (2.32, 0.67 to 8.03).

CONCLUSIONS

Evidence is lacking that clinical outcomes are improved by using antibiotics active against atypical pathogens in all cause non-severe community acquired pneumonia. Although such antibiotics were superior in the management of patients later shown to have legionella related pneumonia, this pathogen was rarely responsible for pneumonia within the included trials. beta lactam agents should remain the antibiotics of initial choice in adults with non-severe community acquired pneumonia.

Is it possible to distinguish between atypical pneumonia and bacterial pneumonia?: evaluation of the guidelines for community-acquired pneumonia in Japan

The Japanese Respiratory Society (JRS) published the guidelines for the management of community-acquired pneumonia in 2000. The guidelines set up nine parameters and criteria for the differential diagnosis of atypical pneumonia and bacterial pneumonia based on clinical symptoms, physical signs and laboratory data. To evaluate the performance of these guideline criteria, 91 cases of Chlamydia pneumoniae (53 cases were pure-C. pneumoniae and 38 cases were mixed-C. pneumoniae pneumonia), 103 cases of Mycoplasma pneumoniae (86 cases were pure-M. pneumoniae and 17 cases were mixed-M. pneumoniae pneumonia) and 144 cases of bacterial (Streptococcus pneumoniae and/or Haemophilus influenzae) pneumonia were analyzed. The accordance rate for a suspected atypical pneumonia with the guideline criteria was 84.8% for pure-M. pneumoniae pneumonia and 60.3% for pure-C. pneumoniae pneumonia, but only 9.0% for bacterial pneumonia, 12.1% for mixed-C. pneumoniae pneumonia and 16.6% for mixed-M. pneumoniae pneumonia. Overall, the sensitivity and specificity of the criteria in the JRS guidelines were 75.5% and 90.9%, respectively. Our results indicated that the differentiation of pneumonia in the JRS guidelines is useful for the diagnosis of M. pneumoniae pneumonia, but difficult to apply to the diagnosis of C. pneumoniae pneumonia.

Management of acute bronchitis in healthy adults

Acute respiratory infections (ARIs) are the most common infections in humans, accounting for half of all acute conditions each year in the United States. Acute bronchitis episodes represent a significant portion of these illnesses. This article focuses on acute bronchitis in otherwise healthy individuals.

Monotherapy versus Dual Therapy for Community-Acquired Pneumonia in Hospitalized Patients

Several medical-specialty professional societies have suggested that combination therapy with a beta -lactam plus a macrolide or doxycycline or monotherapy with a "respiratory quinolone" (i.e., levofloxacin, gatifloxacin, moxifloxacin, or gemifloxacin) are optimal first-line therapy for patients hospitalized with community-acquired pneumonia. These recommendations are based predominantly on retrospective studies that suggest improved rates of morbidity and mortality and hospital length of stay among patients treated in such a fashion. Well-designed, prospective, randomized studies confirming this tenet of therapy have not been published, although numerous prospective studies have provided indirect confirmation. The biological rationale for such a differential response (i.e., favoring combination therapy or fluoroquinolone therapy) includes the immunomodulatory effects of macrolides or more-optimal treatment of primary infection or coinfection with atypical pathogens. Well-designed, prospective, randomized trials are required to best define the effectiveness of combination therapy with a beta -lactam plus macrolide or doxycycline or with a respiratory quinolone in hospitalized patients with community-acquired pneumonia.

Contribution of C-Reactive Protein to the Diagnosis and Assessment of Severity of Community-Acquired Pneumonia

STUDY OBJECTIVE

To assess the usefulness of serum C-reactive protein (CRP) in the diagnosis and treatment approach of patients with community-acquired pneumonia (CAP).

DESIGN

Population-based case-control study.

SETTING

A mixed residential-industrial urban area of 74,368 adult inhabitants in the Maresme region (Barcelona, Spain).

PATIENTS

From December 1993 to November 1995, all subjects who were > 14 years of age, were living in the area, and had received a diagnosis of CAP, which had been confirmed by chest radiographs and compatible clinical outcome, were registered. Patients from residential care facilities were excluded. Serum samples were assayed for CRP in the acute phase of the disease. Data from 201 patients with CAP were compared with 84 healthy control subjects matched by age, sex, and municipality, as well as with 25 patients with initially suspected pneumonia that was not confirmed at follow-up. Median CRP levels were 110.7, 1.9, and 31.9 mg/L, respectively. The thresholds of the test for discriminating among these three groups of subjects were 11.0 and 33.15 mg/L.

RESULTS

Eighty-nine patients (44.8%) had an identifiable etiology. The most common pathogens were Streptococcus pneumoniae, viruses, and Chlamydia pneumoniae, followed by Mycoplasma pneumoniae, Legionella pneumophila, and Coxiella burnetii. There were statistically significant differences in the median CRP levels in pneumococcal (166.0 mg/L) and L pneumophila (178.0 mg/L) etiologies compared to other causative pathogens. Lower levels of CRP were found in pneumonia caused by viruses and C burnetii as well as in negative microbiological findings. The median CRP levels in hospitalized patients were significantly higher than in outpatients (132.0 vs 76.9 mg/L, respectively; p < 0.001). Considering a cut point of 106 mg/L in men and 110 mg/L in women for deciding about the appropriateness of inpatient care, CRP levels showed a sensitivity of 80.51% and a specificity of 80.72%.

CONCLUSIONS

Serum CRP level is a useful marker for establishing the diagnosis of CAP in adult patients with lower respiratory tract infections. High CRP values are especially high in patients with pneumonias caused by S pneumoniae or L pneumophila. Moreover, high CRP values are suggestive of severity, which may be of value in deciding about the appropriateness of inpatient care.

Guidelines for community-acquired pneumonia in the ICU

Community-acquired pneumonia remains a common and serious condition worldwide. Severe community-acquired pneumonia requiring ICU admission is a distinct entity with different pathogens, outcomes, and management. The mortality rate in severe community-acquired pneumonia can be more than 50%. Over the past decade, some international guidelines for the management of community-acquired pneumonia have been developed in an attempt to optimize patient care. These guidelines have developed prediction tools to direct clinicians in the management of community-acquired pneumonia, including when to admit a patient to the ICU and selecting appropriate investigations and antimicrobial therapy. The individual recommendations of these guidelines and the guidelines as a whole require further studies.

Aetiology and Clinical Presentation of Mild Community-Acquired Bacterial Pneumonia

A prospective study was initiated to analyse the bacterial aetiology and clinical picture of mild community-acquired pneumonia in Slovenia using the previously described Pneumonia Severity Index. Radiographically confirmed cases of pneumonia in patients treated with oral antibiotics in seven study centres were included. An aetiological diagnosis was attempted using culture of blood and sputum, urinary antigen testing for Streptococcus pneumoniae and Legionella pneumophila, and antibody testing for Mycoplasma pneumoniae, Chlamydia pneumoniae, and Legionella pneumophila in paired serum samples. One hundred thirteen patients were evaluable for clinical presentation and 109 for aetiological diagnosis. At least one pathogen was detected in 62.4% patients. The most common causative agents were Mycoplasma pneumoniae in 24.8%, Chlamydia pneumoniae in 21.1%, and Streptococcus pneumoniae in 13.8% of patients. Dual infection was detected in 8.3% of patients. Most patients suffered from cough, fatigue, and fever. Patients with atypical aetiology of pneumonia differed from those with typical bacterial pneumonia or pneumonia of unknown aetiology in age, presence of dyspnea, and bronchial breathing on lung auscultation. Patients with pneumococcal, chlamydial, and mycoplasmal infections differed in age, risk class, presence of dyspnea, bronchial breathing, and proteinuria. There was an overlap of other clinical symptoms, underlying conditions, and laboratory and radiographic findings among the groups of patients classified by aetiology. Since patients with mild community-acquired pneumonia exhibit similar clinical characteristics and, moreover, since a substantial proportion of cases are attributable to atypical bacteria, broad-spectrum antibiotic treatment seems to be recommended.

Recomendações de abordagem diagnóstica e terapêutica da pneumonia da comunidade em adultos imunocompetentes

The Portuguese Respiratory Society makes a series of recommendations as to the state of the art of the diagnostic, therapeutic and preventive approach to community-acquired pneumonia in immunocompetent adults in Portugal. These proposals should be regarded as general guidelines and are not intended to replace the clinical sense used in resolving each individual case. Our main goal is to stratify the patients according to the risk of morbidity and mortality in order to justify the following decisions more rationally: the choice of place of treatment (outpatient or inpatient), diagnostic tests and antimicrobial therapy. We also make a set of recommendations for the prevention of CAP. We plan to conduct multi-centre prospective studies, preferably in collaboration with other scientific societies, in order to be able to characterise the situation in Portugal more accurately and regularly update this document.

Community-acquired pneumonia in the emergency department: a practical approach to diagnosis and management

Pneumonia is one of the most common conditions for which patients seek emergency care. It is a challenging infection in that the spectrum of illness ranges from the nontoxic patient appropriate for outpatient antibiotics to the critically ill patient requiring intensive care hospitalization. Current data and diagnostic technology provide the emergency physician with the tools for an appropriately rapid evaluation and consideration of the differential diagnosis. Key critical thinking and application of published findings allow for intelligent empirical antibiotic treatment and risk stratification for the best disposition. Although antibiotic-resistant organisms increasingly are being identified, patients continue to benefit from early institution of standard ED treatment. Coverage for atypical organisms improves patient response and outcome. Finally, identification and treatment of the complications of pneumonia and accompanying sepsis must be considered by the ED physician when evaluating critically ill patients.

Detection of Chlamydia pneumoniae in cholesteatoma tissue: any pathogenetic role?

BACKGROUND

Acquired cholesteatoma is a complication of chronic otitis media that is usually associated with an intense local inflammatory reaction. Cholesteatoma probably arises from epithelial migration close to an ongoing host inflammatory response attributable to a chronic bacterial infection. Chlamydia pneumoniae is an intracellular microorganism associated with several pathologic conditions originally considered noninflammatory, including asthma, atherosclerosis, and Alzheimer disease. To investigate a possible relationship between C. pneumoniae and the development of cholesteatoma, tissue was studied in three different layers by polymerase chain reaction analysis. The results were compared with those relative to other two common middle-ear pathogens, Mycoplasma pneumoniae and Haemophilus influenzae.

METHODS

Cholesteatoma specimens were collected from 32 patients undergoing middle ear surgery. A series of 5 microm-thick specimens were obtained at three different tissue levels, internal (matrix), intermediate (perimatrix), and external (granulation tissue), and processed by polymerase chain reaction for detection of C. pneumoniae, H. influenzae, and M. pneumoniae. Fragmentation and polymerase chain reaction amplification were carried out using two substantially different techniques.

RESULTS

C. pneumoniae was detected with either polymerase chain reaction techniques in the internal layers in 16 of the 32 cholesteatomas (50%), associated with a positive finding in the intermediate layer in two cases and in the external layer in one case. Four specimens contained H. influenzae, always in the external layer, whereas none contained M. pneumoniae.

CONCLUSIONS

The close relationship between cholesteatoma and C. pneumoniae demonstrated by the findings of this study could suggest a direct cause and effect link between the pathogen action and the clinical manifestations. Otherwise, a facilitated colonization by C. pneumoniae and chronic pathology of the ear could both take origin from a peculiar immunologic background of the host.

Community-acquired pneumonia in southeast Asia: the microbial differences between ambulatory and hospitalized patients

STUDY OBJECTIVES

To determine microbial agents causing community-acquired pneumonia (CAP) in Southeast Asia.

DESIGN

A prospective study.

SETTING

Three general hospitals in Thailand.

PATIENTS

Two hundred forty-five adult patients fulfilling the clinical criteria of CAP from September 1998 to April 2001.

INTERVENTIONS

Investigations included sputum Gram stain and culture, blood culture, pleural fluid culture (if presented), urine antigen for Legionella pneumophila and Streptococcus pneumoniae, and serology for Mycoplasma pneumoniae, Chlamydia pneumoniae, and L pneumophila.

RESULTS

There were 98 outpatients and 147 hospitalized patients included in the study, and an organism was identified in 74 of 98 outpatients (75.5%) and 105 of 147 of the hospitalized patients (71.4%). C pneumoniae (36.7%), M pneumoniae (29.6%), and S pneumoniae (13.3%) were the most frequent causative pathogens found in outpatients, while S pneumoniae (22.4%) and C pneumoniae (16.3%) were the most common in hospitalized patients. There was a significantly higher incidence of C pneumoniae (36.7% vs 16.3%, respectively; p < 0.001) and M pneumoniae (29.6% vs 6.8%; p < 0.001, respectively) in the outpatients than in the hospitalized patients. The incidence of S pneumoniae, L pneumophila, and mixed infections was not different between the groups. Mixed infections were presented in 13 of 98 outpatients (13.3%) and 9 of 147 hospitalized patients (6.1%), with C pneumoniae being the most frequent coinfecting pathogen.

CONCLUSIONS

The data indicate that the core organisms causing CAP in Southeast Asia are not different from those in the Western countries. The guidelines for the treatment of patients with CAP, therefore, should be the same.

The contribution of blood cultures to the clinical management of adult patients admitted to the hospital with community-acquired pneumonia: a prospective observational study

STUDY OBJECTIVE

To assess the clinical usefulness of blood cultures (BCs) in the management of patients hospitalized with community-acquired pneumonia (CAP).

DESIGN

A prospective, observational study to investigate the contribution of BCs to the management and outcomes of adult patients presenting with CAP.

SETTING

Nineteen Canadian hospitals.

PATIENTS

Adults admitted to the hospital with CAP between January 1, 1998, and July 31, 1998.

INTERVENTIONS

The courses of therapy in patients for whom BC results yielded organisms considered to be clinically significant were analyzed to determine whether the BCs had contributed to management or outcome.

MEASUREMENTS AND RESULTS

Forty-three of 760 patients had significantly positive BC results. Patients with CAP who had BCs performed had a 1.97% chance (15 of 760 patients) of having a change of therapy directed by BC results. Patients in whom BCs yielded positive results had a 34.8% chance (15 of 43 patients) of having a change in therapy determined by BC results, and had a 58.1% chance (25 of 43 patients) of having a course of therapy contraindicated by BC results. Severity of illness, as measured by the pneumonia severity index, correlated poorly with the yield of BCs. BC results were positive in 8.0% of patients in risk classes I and II, 6.2% of patients in risk class III, 4.6% of patients in risk class IV, and 5.2% of patients in risk class V.

CONCLUSION

BCs have limited usefulness in the routine management of patients admitted to the hospital with uncomplicated CAP.

Addition of a macrolide to a beta-lactam-based empirical antibiotic regimen is associated with lower in-hospital mortality for patients with bacteremic pneumococcal pneumonia

To assess the association between inclusion of a macrolide in a beta-lactam-based empirical antibiotic regimen and mortality among patients with bacteremic pneumococcal pneumonia, 10 years of data from a database were analyzed. The total available set of putative prognostic factors was subjected to stepwise logistic regression, with in-hospital death as the dependent variable. Of the 409 patients analyzed, 238 (58%) received a beta-lactam plus a macrolide and 171 (42%) received a beta-lactam without a macrolide. Multivariate analysis revealed 4 variables to be independently associated with death: shock (P<.0001), age of >or=65 years (P=.02), infections with pathogens that have resistance to both penicillin and erythromycin (P=.04), and no inclusion of a macrolide in the initial antibiotic regimen (P=.03). For patients with bacteremic pneumococcal pneumonia, not adding a macrolide to a beta-lactam-based initial antibiotic regimen is an independent predictor of in-hospital mortality. However, only a randomized study can definitively determine whether this association is due to a real effect of macrolides.

Community-acquired pneumonia in elderly patients

CAP in elderly patients carries a significant economic and clinical burden and will be more commonly encountered in the future as the US population ages. Diagnosis may be obscured by a nonclassic presentation in an elderly patient, and the clinician needs to be especially suspicious of pneumonia whenever the clinical status of an elderly patient deteriorates. The single most important clinical decision is the site of care; this determination is not always based on clinical factors but also on social factors. Severity assessment is key to stratifying appropriate therapy and to predicting outcome. Timely and appropriate empiric therapy enhances the likelihood of a good clinical outcome, although clinical resolution may be more delayed than in younger patients. Newly emerging patterns of antibiotic resistance have altered recent guidelines for CAP treatment; DRSP is now a consideration in elderly patients because an age older than 65 years is a well-described risk factor for infection with this organism. Prevention should always be implemented, with a focus on pneumococcal and influenza vaccination.

A 22-year-old woman with fulminant Chlamydia pneumoniae pneumonia

Chlamydia pneumoniae (C. pneumoniae) is a common pathogen of community-acquired pneumonia. The clinical features of infection caused by C. pneumoniae are usually mild and it does not progress into respiratory failure in young people. We describe a healthy, immunologically intact, 22-year-old woman with severe respiratory failure caused by C. pneumoniae accompanied by aspergillosis. The infection rapidly progressed and required mechanical ventilation. C. pneumoniae infection should be taken into account when treating patients with rapidly progressive pneumonia even in immunocompetent young adults.

Clinical presentation of community-acquired Chlamydia pneumoniae pneumonia in adults

STUDY OBJECTIVE

To investigate the clinical presentation of community-acquired Chlamydia pneumoniae pneumonia in adults.

DESIGN

Prospective study.

SETTING

Kawasaki Medical School Hospital, Kawasaki Medical School Kawasaki Hospital, and Kurashiki Daiichi Hospital in Japan.

PARTICIPANTS

Forty patients with community-acquired pneumonia with C pneumoniae as the only pathogen identified admitted to three hospitals between April 1996 and March 2001 and their clinical presentations were compared to patients with Streptococcus pneumoniae and Mycoplasma pneumoniae pneumonia.

MEASUREMENTS

The diagnosis of C pneumoniae infection was based on isolation and serologic testing of antibodies by the microimmunofluorescence test.

RESULTS

The clinical presentations, except for shortness of breath, were similar for the three major etiologic agents. The mean temperature of C pneumoniae patients on hospital admission was 37.9 degrees C, which was lower than that of patients with S pneumoniae and M pneumoniae. The mean WBC count on hospital admission was lower in the patients with C pneumoniae (mean, 9,100/microL) than in those with S pneumoniae pneumonia but higher than in those with M pneumoniae pneumonia. No patients required respiratory support or admission to an ICU, and no deaths occurred among the C pneumoniae pneumonia patients.

CONCLUSIONS

Our results indicate that C pneumoniae pneumonia as a single etiologic agent is mild and that the underlying conditions and clinical symptoms closely resemble those of S pneumoniae pneumonia. However, the physical examinations, laboratory findings, and prognostic factors of the C pneumoniae patients resembled those of patients with M pneumoniae pneumonia.

The emerging role of atypical pathogens in community-acquired pneumonia

Community-acquired pneumonia (CAP) constitutes a major cause of morbidity and mortality. Although Streptococcus pneumoniae remains the bacterium most commonly implicated in CAP, the atypical respiratory pathogens Mycoplasma pneumoniae, Legionella species, and Chlamydia pneumoniae are being isolated with increasing frequency Contrary to previous beliefs, these agents are capable of causing severe as well as mild-to-moderate illness. Moreover, they can affect all age groups. Indeed, atypical pathogens are implicated in up to 40% of CAP cases and commonly occur as copathogens in mixed-infection CAP, an etiology associated with particularly high mortality (up to 25%). Laboratory methods for detecting atypical pathogens are slow, and there is significant overlap between atypical and typical CAP manifestations. For these reasons, accurate prediction of etiology cannot be made purely on clinical or radiologic grounds. Consequently, empiric antimicrobial therapy for atypical pathogens (with agents such as macrolides, fluoroquinolones, in some cases tetracyclines, or the new ketolides) warrants careful consideration and now is recommended for the treatment of CAP.