Empiric treatment of ambulatory community-acquired pneumonia: always include treatment for atypical agents

Imaging of pulmonary infections encountered in the emergency department in post-COVID 19 era- common, rare and exotic. Bacterial and viral

Pulmonary infections contribute substantially to emergency department (ED) visits, posing a considerable health burden. Lower respiratory tract infections are prevalent, particularly among the elderly, constituting a significant percentage of infectious disease-related ED visits. Timely recognition and treatment are crucial to mitigate morbidity and mortality. Imaging studies, primarily chest radiographs and less frequently CT chests, play a pivotal role in diagnosis. This article aims to elucidate the imaging patterns of both common and rare pulmonary infections (bacterial and viral) in the post COVID-19 era, emphasizing the importance of recognizing distinct radiological manifestations. The integration of clinical and microbiological evidence aids in achieving accurate diagnoses, and guiding optimal therapeutic interventions. Despite potential overlapping manifestations, a nuanced understanding of radiological patterns, coupled with comprehensive clinical and microbiological information, enhances diagnostic precision in majority cases.

Does empiric therapy for atypical pathogens improve outcomes for patients with CAP?

The present controversy regarding the need to cover atypical pathogens in the empiric therapy of community-acquired pneumonia is related to several issues, including the relevance of terminology, imprecise diagnostic methods, and perceived contradictory results of published evidence. Studies evaluating the time to clinical recovery and the use of earlier endpoints for evaluation suggest that appropriate therapy provides a benefit if an atypical pathogen is a pathogen. Because recent surveillance studies suggest these pathogens are common and until there is the availability of accurate, cost-effective, and easily interpreted laboratory tests to provide the etiologic diagnosis at the time of point of care, empiric therapy of atypical pathogens is supported.

Single tube real time PCR for detection of Streptococcus pneumoniae, Mycoplasma pneumoniae, Chlamydophila pneumoniae and Legionella pneumophila from clinical samples of CAP

We designed a multiplex real time PCR for rapid, sensitive and specific detection of Streptococcus pneumoniae, Legionella pneumophila, Chlamydophila pneumoniae and Mycoplasma pneumoniae. The study cases consisted of 129 patients with community acquired pneumonia (CAP). Bacteriological techniques were implemented for detection of the cultivable organisms. DNA were extracted from sputa, throat swabs, bronchoalveolar lavages and tracheal aspirates and used as templates in real time PCR. The primers and probes were designed for cbpA (S. pneumoniae), p1adhesin (M. pneumoniae), mip (L. pneumophila) and ompA (C. pneumoniae). After optimization of real time PCR for every organism, the experiments were continued in multiplex in a single tube. Of 129 CAP specimens, the positive cultures included 14 (10.85%) for S. pneumoniae, 9 (6.98%) for L. pneumophila and 3 (2.33%) for M. pneumoniae. Four specimens (3.10%) were positive for C. pneumoniae by real time PCR. The sensitivity of our real time PCR was 100% for all selected bacteria. The specificity of the test was 98.26%, 98.34%, 100% and 100% for S. pneumoniae, L. pneumophila, M. pneumoniae and C. pneumoniae, respectively. This is the first report on the use of multiplex real time PCR for detection of CAP patients in the Middle East. The method covers more than 90% of the bacterial pathogens causing CAP.

[Antibiotherapy for acute CAP in adults]

Community acquired pneumonia is one of the most frequent infections. With time, bacterial epidemiology and bacterial resistance evolve and new antibiotics become available. So an up-date on adequate antibiotic use is necessary. We reviewed the epidemiology of pneumonia and the evolution of bacterial resistance. We also collected data on new antibiotics which can be used for this infection such as levofloxacin, moxifloxacin, telithromycin, and pristinamycin. All these drugs are effective on bacteria involved in pneumonia. At this time, only few Streptococcus pneumoniae strains have developed resistance to these drugs. However, resistance to fluoroquinolones is not easily detected with common laboratory techniques. There is no effectiveness difference between the 2 new fluoroquinolones (levofloxacin, moxifloxacin) in clinical studies. However, in bacteriological and pharmacological studies, moxifloxacin seems to be more effective than levofloxacin (500 mg/day). For the treatment of pneumonia due to Legionella pneumophila, fluoroquinolones are now widely recommended. For Streptococcus pneumonia, amoxicillin remain the drug of choice, even for bacteria with a decreased susceptibility to penicillin. The importance of treating atypical pathogens remains to be documented.

The atypical pneumonias: clinical diagnosis and importance

The most common atypical pneumonias are caused by three zoonotic pathogens, Chlamydia psittaci (psittacosis), Francisella tularensis (tularemia), and Coxiella burnetii (Q fever), and three nonzoonotic pathogens, Chlamydia pneumoniae, Mycoplasma pneumoniae, and Legionella. These atypical agents, unlike the typical pathogens, often cause extrapulmonary manifestations. Atypical CAPs are systemic infectious diseases with a pulmonary component and may be differentiated clinically from typical CAPs by the pattern of extrapulmonary organ involvement which is characteristic for each atypical CAP. Zoonotic pneumonias may be eliminated from diagnostic consideration with a negative contact history. The commonest clinical problem is to differentiate legionnaire's disease from typical CAP as well as from C. pneumoniae or M. pneumonia infection. Legionella is the most important atypical pathogen in terms of severity. It may be clinically differentiated from typical CAP and other atypical pathogens by the use of a weighted point system of syndromic diagnosis based on the characteristic pattern of extrapulmonary features. Because legionnaire's disease often presents as severe CAP, a presumptive diagnosis of Legionella should prompt specific testing and empirical anti-Legionella therapy such as the Winthrop-University Hospital Infectious Disease Division's weighted point score system. Most atypical pathogens are difficult or dangerous to isolate and a definitive laboratory diagnosis is usually based on indirect, i.e., direct flourescent antibody (DFA), indirect flourescent antibody (IFA). Atypical CAP is virtually always monomicrobial; increased IFA IgG tests indicate past exposure and not concurrent infection. Anti-Legionella antibiotics include macrolides, doxycycline, rifampin, quinolones, and telithromycin. The drugs with the highest level of anti-Legionella activity are quinolones and telithromycin. Therapy is usually continued for 2 weeks if potent anti-Legionella drugs are used. In adults, M. pneumoniae and C. pneumoniae may exacerbate or cause asthma. The importance of the atypical pneumonias is not related to their frequency (approximately 15% of CAPs), but to difficulties in their diagnosis, and their nonresponsiveness to beta-lactam therapy. Because of the potential role of C. pneumoniae in coronary artery disease and multiple sclerosis (MS), and the role of M. pneumoniae and C. pneumoniae in causing or exacerbating asthma, atypical CAPs also have public health importance.

Severe community-acquired pneumonia due to Legionella pneumophila Serogroup 6

Legionella pneumophila is a common cause of sporadic community-acquired pneumonia, but culture-proven legionellosis is rarely diagnosed. There is no laboratory test for Legionnaires' disease that can detect all patients with the disease. Culture is the standard diagnostic method and should be initiated as soon as possible in suspected cases. We describe a rare case of community-acquired pneumonia caused by L. pneumophila serogroup 6. A 77-year-old man was admitted to a tertiary care hospital because of high fever, productive cough, and progressive dyspnea. Chest radiography showed bilateral pneumonia, which led to respiratory failure necessitating mechanical ventilatory support. Despite antibiotic therapy, his condition continued to deteriorate and acute renal failure also developed. Urine was negative for L. pneumophila. Culture of the sputum yielded L. pneumophila serogroup 6, although there was no elevation of the serum antibody titer. Pneumonia resolved gradually and he was extubated after treatment with levofloxacin followed by erythromycin. L. pneumophila other than serogroup 1 should be included in the differential diagnosis of patients with suspected atypical community-acquired pneumonia.

Acute lung infections in normal and immunocompromised hosts

Pulmonary infections are among the most common causes of morbidity and mortality worldwide, and contribute substantially to annual medical expenditures in the United States. Despite the availability of antimicrobial agents, pneumonia constitutes the sixth most common cause of death and the number one cause of death from infection. Pneumonia can be particularly life-threatening in the elderly, in individuals who have pre-existing heart and lung conditions, in patients who have suppressed or weakened immunity, and in pregnant women. This article discusses some of the important causes of acute lung infections in normal and immunocompromised hosts. Because there often is considerable overlap, infections are categorized by the host immune status that is most likely to be associated with a particular pathogen.

Empiric management of community‐acquired pneumonia in Australian emergency departments

OBJECTIVE

To describe empiric community-acquired pneumonia (CAP) management in Australian hospital emergency departments (EDs) and evaluate this against national guidelines, including use of the pneumonia severity index and antibiotic selection.

DESIGN

A multicentre, cross-sectional, retrospective audit, April 2003 to February 2005.

SETTING

37 Australian hospitals: 22 principal referral hospitals, six large major city hospitals, four large regional hospitals, four medium hospitals and one private hospital.

PARTICIPANTS

Adult patients with a diagnosis of CAP made in the ED. Data on 20 consecutive CAP ED presentations were collected in participating hospitals.

OUTCOME MEASURES

Documented use of the pneumonia severity index, initial antibiotic therapy prescribed in the ED, average length of stay, inpatient mortality, and concordance with national guidelines.

RESULTS

691 CAP presentations were included. Pneumonia severity index use was documented in 5% of cases. Antibiotic therapy covering common bacterial causes of CAP was prescribed in 67% of presentations, although overall concordance with national guidelines was 18%. Antibiotic prescribing was discordant due to inadequate empiric antimicrobial cover, allergy status (including contraindication to penicillin), inappropriate route of administration and/or inappropriate antibiotic choice according to recommendations. There was no significant difference between concordant and discordant antibiotic prescribing episodes in average length of stay (5.0 v 5.7 days; P = 0.22) or inpatient mortality (1.6% v 4.1%; chi2 = 1.82; P = 0.18).

CONCLUSIONS

Antibiotic therapy for CAP prescribed in Australian EDs varied. Concordance with national CAP guidelines was generally low. Targeted interventions are required to improve concordance.

Sinn und Unsinn der Antibiotikatherapie respiratorischer Infekte

Whether an antibiotic successfully eradicates pathogens depends on the pathogens involved, on pharmacokinetics and bioavailability in the target tissue, and on the antimicrobial resistance of the pathogen. Other determinants are drug interactions, individual risk factors, age and compliance with respect to correct dosage and duration of therapy. In many cases, antimicrobial therapy is begun on an empirical basis, because the responsible pathogen can be identified in only half of all respiratory infections. The eradication of the pathogen has to be the first aim if treatment is to be curative and the development of resistance prevented. Long-term prevention of antimicrobial resistance will require a more critical prospective evaluation of the prescription of antibiotics. This paper considers rational and irrational measures in the antimicrobial therapy of respiratory infections.

An economic and outcomes assessment of first-line monotherapy in the treatment of community-acquired pneumonia within managed care

OBJECTIVE

To evaluate the resource consumption and outcomes associated with first-line monotherapy for community-acquired pneumonia, focusing specifically on the use of erythromycin, azithromycin, clarithromycin, and levofloxacin.

STUDY DESIGN

Retrospective managed care database analysis.

PATIENTS AND METHODS

Subjects included patients within a managed care setting over 18 years of age with an initial diagnosis of community-acquired pneumonia from January 1995 to April 2002. Multivariate linear and logistic regression models were used to examine associations with treatment success rates and direct medical costs between antibiotic treatments after controlling for patient demographics and pneumonia risk factors.

MAIN RESULTS

Overall, treatment success rates were high (95.8%), the use of second antibiotics was un common (2.3%), and hospitalizations were infrequent (2.0%) among the 1952 subjects studied. After controlling for patient characteristics and risk factors, significantly lower total costs were associated with erythromycin (92.7% lower, p < 0.001), azithromycin (48.7% lower, p < 0.001), and clarithromycin (21.3% lower, p = 0.015) relative to levofloxacin, with no difference in treatment success between groups. Among newer agents, azithromycin (49.2% lower, p < 0.001) and clarithromycin (21.7% lower, p = 0.013) treatment groups were associated with significantly lower total costs than levofloxacin in the full sample. However, in subjects with a chronic disease score above the sample's mean, only azithromycin was associated with significantly lower total costs (47.9% lower, p < 0.001) relative to levofloxacin.

CONCLUSION

Erythromycin, azithromycin, and clarithromycin were associated with significantly lower total costs than levofloxacin, although treatment success rates did not differ between groups. Following stratification based upon various subset criteria, erythromycin and azithromycin were observed to have significantly lower total costs than levofloxacin. Although these findings may augment clinical guidelines and evidence-based approaches, health plans should consider evaluating their own patient data to see if similar differences exist in their populations.