Legionella pneumonia and HIV infection: a case report

Legionella pneumonia is commonly diagnosed in patients who are chronically immunosuppressed, but it is rarely diagnosed in patients who have HIV/AIDS. We report the successful diagnosis and treatment of Legionella pneumonia in a patient with HIV infection that was diagnosed at the same admission.     

Legionella jordanis: a new species of Legionella isolated from water and sewage.

Legionella jordanis sp. nov., as found in two cultures, is described. One isolate was from river water in Indiana and the other isolate was from sewage in DeKalb County, Ga. The former is the type strain of the species, and is designated BL-540 (ATCC 33623). L. jordanis had a partial relationship to L. bozemanii by direct fluorescent-antibody tests but was unrelated to L. pneumophila, L. dumoffii, L. micdadei, L. gormanii, or L. longbeachae. Legionella phenotypic characteristics, including large amounts of branched-chain cellular fatty acids, were shown by the isolates. Studies of DNA relatedness showed that the two cultures of L. jordanis were only slightly related to the six previously described species of Legionella but were more than 90% related to each other. Indirect fluorescent-antibody tests with human sera suggested that unrecognized human infections with L. jordanis may be occurring.     

The association between bacteria colonizing the upper respiratory tract and lower respiratory tract infection in young children: a systematic review and meta-analysis

BackgroundBacteria colonizing the upper respiratory tract (URT) of young children play a key role in the pathogenesis of lower respiratory tract infection (LRTI).ObjectivesTo systematically review the literature on the association between bacteria colonizing the URT and LRTI among young children.Data sourcesMEDLINE, Academic Search Premier, Africa-Wide Information and CINAHL, Scopus and Web of Science.Study eligibility criteriaStudies published between 1923 and 2020, investigating URT bacteria from LRTI cases and controls.ParticipantsChildren under 5 years with and without acute LRTI.MethodsThree reviewers independently screened titles, abstracts and full texts. Meta-analysis was done using Mantel–Haenszel fixed- or random-effects models.ResultsMost eligible studies (41/50) tested nasopharyngeal specimens when investigating URT bacteria. Most studies were of cross-sectional design (44/50). Twenty-four studies were performed in children in lower- or lower-middle-income countries (LMICs). There was higher prevalence of Haemophilus influenzae (pooled OR 1.60; 95% CI 1.23–2.07) and Klebsiella spp. (pooled OR 2.04; 95% CI 1.17–3.55) from URT specimens of cases versus controls. We observed a positive association between the detection of Streptococcus pneumoniae from URT specimens and LRTI after excluding studies where there was more antibiotic treatment prior to sampling in cases vs. controls (pooled OR 1.41; 95% CI 1.04–1.90). High density colonization with S. pneumoniae (>6.9 log¹⁰ copies/mL) was associated with an increased risk for LRTI. The associations between both Streptococcus and Haemophilus URT detection and LRTI were supported, at genus level, by 16S rRNA sequencing. Evidence for the role of Moraxella catarrhalis and Staphylococcus aureus was inconclusive.ConclusionsDetection of H. influenzae or Klebsiella spp. in the URT was associated with LRTI, while evidence for association with S. pneumoniae was less conclusive. Longitudinal studies assessing URT microbial communities, together with environmental and host factors are needed to better understand pathogenesis of childhood LRTI.     

Respiratory syncytial virus lower respiratory tract infection: our series

The authors report 57 cases of Respiratory Syncytial Virus (RSV) lower respiratory tract infection. The diagnosis was performed by detection of specific serum antibodies of IgM class or by direct detection of RSV antigens in nasopharyngeal specimens. Most of the patients were younger than one year. No one had risk factors for severe RSV infection form. All patients recovered. The authors emphasize the difficulties to discriminate between bronchiolitis and interstitial pneumonitis on the basis of the clinical and radiological features.     

Host defenses against bacterial lower respiratory tract infection

Bacterial pneumonia continues to be a significant cause of morbidity and mortality worldwide. Recent studies have shown that lung epithelia signal through pattern recognition receptors to initiate the innate immune response. Other mediators of innate immunity against bacterial pneumonia include transepithelial dendritic cells, alveolar macrophages, and innate produces of IL-17. CD4+ T cells and B cells play a key role in eliminating and preventing the development of bacterial pneumonias. B cell development and maturation can be modulated by the lung epithelia through BAFF and APRIL, furthering our current understanding of the role of epithelial cells in the immune response.     

Roseomonas gilardii infection: case report and review

Roseomonas gilardii is a bacterium that has been indicated as a rare cause of human infections. The case of a patient presenting with cellulitis and bacteremia secondary to R. gilardii is described together with the clinical characteristics of infection with this organism obtained from a review of cases previously reported.     

Primary malignant melanoma of the lower respiratory tract. Report of a case and literature review

The authors report a case of primary bronchial malignant melanoma, occurring in a 34-year-old woman presenting with persistent cough. At bronchoscopic examination, a polypoid mass was found to occlude the left mainstem bronchus. Biopsies showed a malignant epithelioid tumor resembling an atypical carcinoid. Histochemistry, electron microscopic study, and immunohistochemistry confirmed the diagnosis of melanoma. Physical examination and additional clinical history to exclude other possible primary sites were negative. The patient underwent thoracotomy with left pneumonectomy. Nineteen months after resection she was found to have a histologically similar tumor involving her left adrenal gland. Review of the literature shows that melanoma of the lower respiratory tract has been reported only in adults and has a tendency to present as a central polypoid growth that may be responsive to surgical resection.     

Clinical efficacy and tolerability of grepafloxacin in lower respiratory tract infection

Studies in community-acquired pneumonia (CAP) have compared grepafloxacin, 600 mg o.d. for 7–10 days, with amoxycillin, 500 mg t.d.s., cefaclor, 500 mg t.d.s, or clarithromycin, 250 mg b.d. Grepafloxacin appeared to be clinically as effective as the comparators. In CAP caused by Haemophilus influenzae , grepafloxacin was significantly superior to amoxycillin ( p =0.005) and cefaclor ( p =0.003) and equivalent to clarithromycin in eradicating the infecting organism. Bacterial eradication with grepafloxacin in CAP caused by Moraxella catarrhalis or Streptococcus pneumoniae was effective and equivalent to the comparator antibiotic. In an open study, grepafloxacin was also effective in treating atypical pneumonia caused by Mycoplasma pneumoniae and Legionella pneumophila.
In acute bacterial exacerbations of chronic bronchitis (ABECB), studies have found once-daily treatment with grepafloxacin, 400 mg or 600 mg for 7–10 days, to be equivalent to amoxycillin, 500 mg t.d.s., or ciprofloxacin, 500 mg b.d. In patients with documented infections, bacteriologic eradication with grepafloxacin, 400 mg or 600 mg o.d., was superior to amoxycillin, 500 mg t.d.s.
Results from clinical trials so far indicate that grepafloxacin has a broad spectrum of activity covering all important community-acquired respiratory pathogens, and may be suitable for the empirical treatment of respiratory infection.     

Acute lower respiratory tract infection associated withChlamydia pneumoniae in Germany

Serum specimens from 223 patients with acute lower respiratory tract infection were examined for antibodies toChlamydia pneumoniae using the microimmunofluorescence test. Antibodies toChlamydia pneumoniae were detected in 18 (20 %) of 91 children and 64 (48 %) of 132 adults. Among those individuals, 4 (4 %) children and 15 (11 %) adults had elevated IgG antibody titres indicating acute or recent infection. Specific IgM antibodies were observed in two patients. These results suggest that a significant proportion of lower respiratory tract infections in Germany is caused byChlamydia pneumoniae.     

Epidemiology and resource utilization for patients hospitalized for lower respiratory tract infection

Objectives   To determine referral rates, patient characteristics, and resource utilization for patients admitted to hospital with community-acquired lower respiratory tract infections (LRTI).
Methods   Six hundred and thirteen patients, accounting for 704 LRTI episodes, were included in the study, if the referral diagnosis was LRTI and if both signs and symptoms on admission and patient management were consistent with this diagnosis. Patient records were abstracted to collect information on co-morbidities, patient demographics, resource utilization, episode outcome, pharmacy prescribing and diagnostic service utilization.
Results   Annual hospital admissions for LRTI ranged from 15 per 10 000 population in the age range 16–40 years to over 300 per 10 000 in the population aged >79 years, with a population average of 62.3 per 10 000. Less than 37% of admissions were for community-acquired pneumonia and the majority of episodes were in patients with pre-existing respiratory disease (41.2%). Marital status, gender, diabetic status, type of infection and number of days in hospital within the past year were all significantly associated with changes in mean length of stay.
Conclusions   Hospital episodes of LRTI are seen predominantly in the over-60 age group, which account for almost 90% of bed day utilization, yet represent only 27% of the adult population. Referral of patients to hospital with LRTI represents a major resource implication for secondary health-care provision.     

Predicting the duration of symptoms in lower respiratory tract infection.

BACKGROUND: Acute lower respiratory tract infection (LRTI) presenting in primary care has a long natural history. Antibiotic treatment makes little or no difference to the duration of cough. Limited information is currently available regarding predictors of illness duration. AIM: To determine predictors of illness duration in acute LRTI in primary care. DESIGN OF STUDY: Secondary analysis of trial data to identify independent predictors of illness severity and duration. SETTING: Primary care. METHOD: Eight-hundred and seven patients aged 3 years and over with acute illness (21 days or less) presenting with cough as the main symptom plus at least one symptom or sign from sputum, chest pain, dyspnoea, or wheeze were recruited to the study. Main outcomes were duration of symptoms (rated at least a slight problem) and more severe symptoms (rated at least moderately bad). RESULTS: The average duration of cough (rated at least a slight problem) was 11.7 days and was shorter among children (duration -1.72 days; 95% confidence interval [CI] = -3.02 to -0.41) or in individuals with a history of fever (-1.22 days; 95% CI = -0.18 to 2.27). The duration of cough was longer among those with restricted activities on the day they saw the doctor (+0.69 days for each point of a 7-point scale). The duration of more severe symptoms was longer in those with a longer duration of symptoms prior to consultation, with a more severe cough on the day of seeing the doctor, and restriction of activities on the day of seeing the doctor. CONCLUSION: Illness duration may be predicted from a limited number of clinical symptoms and from prior history. These findings should be subjected to validation in a separate population. To minimise expectation about rapid resolution of illness, adults who have restricted activities could be advised that they are likely to experience symptoms for longer.     

Rhinovirus and the lower respiratory tract

Human rhinoviruses (HRVs) are well-recognised causes of common colds and associated upper respiratory tract complications such as sinusitis and otitis media. This article reviews information linking HRV infection to illness in the lower respiratory tract. HRVs are capable of efficient replication in vitro at temperatures present in the tracheobronchial tree and have been shown to cause productive infection, elaboration of cytokines and chemokines, and up-regulation of cell surface markers in human bronchial epithelial cells. In situ hybridisation studies have proven that HRV infection occurs in the tracheobronchial tree following experimental infection. Clinical studies report that HRV infection is the second most frequently recognised agent associated with pneumonia and bronchiolitis in infants and young children and commonly causes exacerbations of pre-existing airways disease in those with asthma, chronic obstructive pulmonary disease or cystic fibrosis. HRV infection is associated with one-third to one-half of asthma exacerbations depending on age and is linked to asthma hospitalisations in both adults and children. Limited information implicates HRV infection as a cause of severe lower respiratory tract illness in older adults and in highly immunocompromised hosts, particularly bone marrow transplant recipients. More information is needed about the pathogenesis of HRV infection with regard to lower respiratory tract complications in these diverse patient groups. Given the large unmet medical need associated with HRV infections, safe and effective antiviral agents are needed for both prevention and treatment of these infections.     

Characteristics of Chlamydia trachomatis infection in hospitalized infants with lower respiratory tract infection.

BACKGROUND AND PURPOSE: To study the epidemiology, presentation and laboratory findings of Chlamydia trachomatis pneumonia in hospitalized infants younger than 6 months. METHODS: Between January 2001 and December 2005, infants younger than 6 months admitted to the children's medical center of Taipei Veterans General Hospital with the diagnosis of acute bronchiolitis, bronchopneumonia or pneumonia were prospectively studied. Chest radiograph findings were reviewed in all patients. Basic laboratory examinations performed included white blood cell count and eosinophil count. C. trachomatis was detected via enzyme-linked immunosorbent assay antigen test and the titers of immunoglobulin G and immunoglobulin M by indirect immunoperoxidase assay. RESULTS: A total of 60 infants, 32 males and 28 females, were included. C. trachomatis infection was detected in 30% of patients (18/60). The median age was 2.5 months (range, birth to 6 months). Fever was not detected in 72% of patients (13/18). Only 22% (4/18) of these patients had the characteristic staccato cough. The mean duration of symptoms before admission was 8 days (range, 1 day to 2 months). Rhinorrhea was a prodromal symptom in 67% (12/18) of patients, with a mean pre-onset duration of 7 days (range, 1 to 14 days). Eighty three percent (15/18) of the patients had tachypnea, with a mean duration of 3.2 days (range, 1 to 7 days). Conjunctivitis was noted before admission in 6 patients (33%). Only peripheral eosinophils showed statistically significant difference between Chlamydia-positive and -negative disease (p=0.046), and may be clinically useful in cases of suspected C. trachomatis infection. Mixed infection with other pathogens including adenovirus, respiratory syncytial virus, Mycoplasma pneumoniae, cytomegalovirus and Streptococcus pneumoniae was found in 27% (5/18) of patients. CONCLUSIONS: C. trachomatis is not infrequent and plays an important role in infants younger than 6 months old hospitalized due to lower respiratory tract infection.     

Aetiology and prediction of pneumonia in lower respiratory tract infection in primary care

BACKGROUND: Knowledge of predominant pathogens and their association with outcome are of importance for the management of lower respiratory tract infection (LRTI). As antibiotic therapy is indicated in pneumonia and not in acute bronchitis, a predictor of pneumonia is needed. AIM: To describe the aetiology and outcome of LRTI in adults with pneumonic and adults with non-pneumonic LRTI treated in general practice and to identify predictors of radiographic pneumonia. DESIGN OF STUDY: Prospective, observational study. SETTING: Forty-two general practices and an outpatient clinic at the Department of Infectious Diseases, Odense University Hospital, Denmark. METHOD: A total of 364 adults diagnosed with community-acquired LRTI by their GP were studied with chest radiography, vital signs, biochemical markers of inflammation (C-reactive protein [CRP] and leukocyte count), and microbiological examinations. Primary outcome measure was hospitalisation within 4 weeks. RESULTS: Pneumonia was radiographically verified in 48 of 364 patients (13%). Bacterial infection was seen more often in patients with pneumonia (33% versus 17%, P<0.001), and viral infection more often in non-pneumonic patients (26% versus 13%, P<0.05). Hospitalisation was more common in patients with pneumonia compared to non-pneumonic patients (19 versus 3%, P<0.001); and in patients with pneumococcal infection compared with patients without pneumococcal infection (26 versus 4%, P = 0.001). The positive predictive value of GPs' diagnosis of pneumonia was low (0.23), but the vital signs, CRP, and leukocyte count had comparably low positive predictive values (0.23-0.30). CONCLUSION: Streptococcus pneumoniae was the most common bacterial pathogen. The risk of hospitalisation was highest among patients with pneumonia or pneumococcal infection; this emphasises the importance of coverage of S. pneumoniae when treatment is indicated. CRP should not be introduced for diagnosis of radiographic pneumonia in general practice before its use has been investigated in prospective, controlled intervention trials using CRP-guided treatment algorithms.     

肺表面活性蛋白A基因多态性与呼吸道合胞病毒下呼吸道感染的相关性研究

目的探讨肺表面活性蛋白（SP）-A1-1101C/T和SP-A2-1649G/C位点基因多态性与呼吸道合胞病毒下呼吸道感染（RSV-LRTI）的相关性。方法应用聚合酶链反应-限制性酶切片段长度多态性（PCR-RFLP）分析法检测200例病例组和150例健康对照组2个位点的基因多态性,并进行基因型、等位基因型频率分析;采用DNA测序法进行测序分析。结果 1.病例组SP-A1-1101C/T位点TT、CT基因型频率分别为76.0%、24.0%,T、C等位基因频率分别为88.0%、12.0%;对照组TT、CT基因型频率分别为80.7%、19.3%,T、C等位基因频率分别为90.3%、9.7%,两组基因型及等位基因频率差异无统计学意义（χ2=1.088、0.953,P〉0.05）。2.病例组SP-A2-1649G/C位点CC、CG、GG基因型频率分别为41.5%、50.5%、8.0%,C、G等位基因频率分别为66.8%、33.2%;对照组CC、CG、GG基因型频率分别为43.3%、49.3%、7.4%,C、G等位基因频率分别为68.0%、32.0%,两组基因型及等位基因频率无统计学意义（χ2=0.141、0.122,P〉0.05）;但该位点基因型和等位基因在轻度和重度患儿间的差异有统计学意义（χ2=6.664、5.207,P〈0.05）,携带G等位基因的个体患重度RSV-LRTI的风险是患轻度风险的1.656倍,（OR=1.656,95%CI：1.072～2.559,P=0.023〈0.05）。结论温州地区汉族儿童存在SP-A1-1101C/T、SP-A2-1649G/C基因多态性,未发现其与RSV-LRTI疾病易感性存在关联,但携带SP-A2-1649G等位基因的个体患重度RSV-LRTI的风险是患轻度风险的1.656倍,表明G等位基因可能是影响RSV-LRTI疾病严重程度的一个候选基因。