Legionella longbeachae; don't miss it!

We here report on two immunocompetent patients admitted to our hospital within 3 weeks' time, both suffering from pneumonia caused by Legionella longbeachae (L. longbeachae). The pathogen was identified in broncho-alveolar lavage (BAL) liquid by Polymerase Chain Reaction (PCR), whereas sputum cultures remained negative. This organism is worldwide still relatively unknown and consequently underdiagnosed. However, with an increasing number of confirmed infections in Europe and more specifically in the Netherlands, early awareness and diagnostic measurements are indicated. As routine laboratory techniques like the urine antigen test do not detect L. longbeachae, we advocate early use of specific tests for non-pneumophila Legionella species such as PCR. Furthermore, we advocate the start of empirical antibiotic therapy (i.e. ciprofloxacin) and continuation in suspected cases.

[A Case of Severe Legionella longbeachae Pneumonia and Usefulness of LAMP Assay]

Urinary antigen test is frequently used as a routine laboratory test for early diagnosis of Legionella infection, which is especially suitable for ordinary Legionella pneumophila serogroup 1, but not for other types of Legionella. We report a case of severe pneumonia caused by Legionella longbeachae, where a method of loop-mediated isothermal amplification (LAMP) assay contributed an important role for the early detection. This case involved an 83-year-old man who developed fever, dyspnea, and productive cough. Since the medication of prescribed ceftriaxone had not been effective, he visited the emergency room of our hospital, where an X-ray revealed a severe pneumonia harboring a consolidation with air bronchogram in his right lower lung. His sputum and urine were subjected to the routine bacterial culture or the urinary antigen test for Legionella, which initially brought negative results. However, a positive result of LAMP assay enabled early diagnosis of Legionella pneumonia. Later, the bacterial cultures of sputum made some progress and 16S rRNA sequencing provided a proof of L. longbeachae. This LAMP assay may bring a benefit for the patients with Legionella pneumonia by enabling early detection of not only specific L. pneumophila serogroup 1, but also of the other Legionella species.

[Roentgenological picture of pneumonia caused by Legionella: on the materials of outbreak in town Verkhnyaya Pyshma]

Chest X-ray is the most common and widely used diagnostic procedure. Chest X-ray is frequently performed not only due to lungs diseases but also in other organs' diseases which indirectly affects lungs. At present computer tomography (CT) which has high resolution becomes to be more and more important. As in other diagnostic method, the main aim of CT is to confirm or reject the presence of disease. During outbreak of pneumonia in town Verkhnyaya Pyshma (Sverdlovsk region), all patients with suspected legionellosis underwent chest X-ray in front and lateral views. In several cases, computer tomography was performed.

Légionellose à Legionella gormanii de découverte fortuite et leucémie lymphoïde chronique : à propos d'un cas et revue de la littérature

Legionellosis due to other species than Legionella pneumophila is rarely described in human cases. It has been reported in immunocompromised patients with respiratory symptoms of pneumonia. We report a case of legionellosis in an immunocompromised 54-year-old man hospitalized for a blood transfusion. A routine pulmonary X- Ray was made and then a bronchoalveolar lavage was collected in which Legionella gormanii was identified. The diagnostic of legionellosis must be considered in all immunocompromised patients presenting with any pulmonary symptoms.

Pulmonary disease in liver transplant recipients. Spectrum of CT features

PURPOSE

To determine the features of pulmonary disease in liver transplant recipients by CT.

MATERIAL AND METHODS

Of 792 patients, 102 were referred to thoracic CT 3-2093 days after the transplantation procedure (median 107 days). All CT studies were retrospectively analyzed and correlated with clinical, microbiological, serological and histopathological findings.

RESULTS

Eighty-eight of 102 patients (86%) had an abnormal CT. In 25 patients (25%), an elevated right hemidiaphragm, basal atelectasis and small effusions were the only abnormalities. Fourty-one patients (40%) displayed an infiltrate and 13 (13%) a mass lesion. Evidence of cytomegalovirus (CMV) infection was found in 20 patients. CMV pneumonia was suggested by an interstitial pattern of pneumonia on CT (n=13). Pneumocystis carinii pneumonia was highlighted by peribronchovascular infiltrates (n=5/8), bacterial pneumonia (n=24) including legionellosis (n= 13) by bilateral effusions (n=14) and lobar consolidation (n= 13). In 7/41 patients (17%) with both clinically apparent pulmonary disease and CT signs of pneumonia, no pathogen could be detected. Neoplastic disease was mostly due to tumor recurrence (n=6).

CONCLUSION

Thoracic CT of liver transplant recipients aids in detecting and classifying both infectious and neoplastic complications.

Relapsing life threatening community acquired pneumonia due to rare Legionella species responsive to ceftriaxone and aztreonam

A 24 year old Saudi housewife was admitted thrice with life threatening community acquired pneumonia. Even though she responded to an initial cocktail of cefriaxone, erythromcin, rifampicin and flucloxacillin during the second admission, she relapsed within four days of discharge when she was on erythromycin only. During the third admission she was put on ceftriaxone and aztreonam and recovered fully without any relapse. Serology results received later showed Legionella IgM titres of more than 1:256 for Legionella micdadei and Legionella bozemanii, and IgG titres of Legionella hackeliae. This case demonstrates relapsing pneumonia due to Legionella micdadei and bozemanii infection, and previous exposure to Legionella hackeliae. Both species, that is, Legionella micdadei and bozemanii, are resistant to erythromycin, but responded very well to a combination of ceftriaxone and aztreonam have not been used previously for the treatment of Legionnaires diseases.

Radiological manifestations of Legionella/Legionella-like organisms

The chest radiograph of Legionellosis has been described in many reports. Although some attempted to describe patterns which are specific for Legionella, in fact, the roentgenographic findings in Legionella infection vary widely and depend largely on when in the course of illness the radiograph is obtained. Certain temporal characteristics, however, can serve to enhance the likelihood of the diagnosis of Legionella pneumonitis. Initial focal infiltrates are most commonly poorly marginated with 10% presenting with concomitant pleural effusion. The infiltrates often spread to contiguous lobes eventually becoming bilateral, with incidence of pleural effusions reaching 35%. This progression often occurs despite appropriate antimicrobial therapy and often in the face of clinical improvement. A similar pattern of progression also occurs in immunocompromised individuals; in addition, a high rate of cavitation and hilar adenopathy is seen in this subset of patients. A prolonged resolution phase of up to 6 months is common with rare development of residual densities. Correlating radiographic features with disease severity and mortality have largely been unsuccessful.

Lung abscess caused by Legionella micdadei

We describe a case of lung abscess caused by sporadic infection with Legionella micdadei in a patient with AIDS. L micdadei infection can be very difficult to diagnose because the organism stains only weakly Gram negative, requires special culture media, and is not detectable with some direct fluorescent antibody tests that are directed only at Legionella pneumophila. Since it can stain acid fast, it may be confused with mycobacteria. The abscess was successfully treated using antibiotics and percutaneous catheter drainage.

[Legionnaires' disease in intensive care patients. Results of plain film thoracic radiography]

We reviewed the chest radiographs and clinical data of 30 patients in an intensive care unit with legionellosis diagnosed by significant serological findings (n = 18), microscopic demonstration of the organism in the transtracheal aspirate (n = 5) or both (n = 7) and investigated the correlation between the identification of Legionella and signs of pulmonary infection. In 13 patients legionnaires' disease was diagnosed with a high degree of confidence. Typical radiographic findings included distal air space disease, which initially appeared to be unilateral, progressing towards bilateral infiltrates. Patchy infiltration at the onset of disease was followed by consolidation. Small pleural effusions were common, while no abscess formation was observed. Characteristically, infiltration persisted for weeks even with clinical convalescence. These radiological findings correspond well with observations in otherwise healthy patients with legionnaire's disease. In 10 patients the etiology of pulmonary infiltrates could not be identified. Seven patients did not develop radiological or clinical signs of pneumonia; therefore, the serological/microscopic detection of Legionella was not interpreted as legionnaires' disease. According to the results of our investigation the diagnosis of legionnaires' disease requires radiological findings in addition to laboratory data.

[Analysis of chest radiographs of culture positive Legionella pneumonia in Japan, 1980-1990. Working Party for Legionellosis, Japanese Ministry of Health and Welfare]

We analyzed the initial and follow-up chest radiographs of 28 patients with culture-positive Legionella pneumonia, and developed a scoring system to quantitate the severity of radiological findings for pneumonia. Intrapulmonary shadows were observed on the initial chest radiograph in 26 patients, but pleural effusion was noted in only one. In one patient the initial chest radiograph had probably been obtained too early to reveal any pulmonary change. Alveolar shadows were noted on the initial radiograph in 21 (81%) patients, and interstitial shadows in 5 (19%). In ten (38%) patients shadows were present in both lung fields. Shadows were prominent in the middle and lower lung fields. A cavity was noted in only one patient, and pleural effusion was also noted at some time during the clinical course in 19 (70%). A large amount of pleural effusion was observed in four patients. The average pneumonia severity score was 3.3 in the 9 patients who survived, and 5.1 in the 17 who died (p > 0.05). The mortality rate was 53% in the 17 patients with pneumonia severity score of 5 or less and 89% in the 9 patients with a score of 6 or more (p > 0.05). Twelve patients died within one week after the initial chest radiograph was obtained. There were no differences among patients with community-acquired infection with or without underlying disease and those with nosocomial infection in characteristic and extension of shadow, presence of pleural effusion, or pneumonia score. The chest radiograph of Legionella pneumonia include bilateral shadow findings characteristic, pleural effusion and rapid progression of shadow, and are clinically useful for diagnosis.

The radiologic manifestations of Legionella pneumonia

A number of radiologic features on chest X-ray may aid in diagnosis and management of the patient with legionella infection. The infiltrates in legionnaires' disease frequently progress despite initiation of appropriate antibiotic therapy. Pleural effusion is common and occasionally seen even in the absence of lung field infiltrates. Pleural-based infiltrates associated with pleuritic pain may mimic pulmonary embolism. Circumscribed peripheral densities are commonly seen in immunosuppressed patients. Cavitation is also a prominent feature in this patient group and may develop during clinical improvement. Radiographic severity does not correlate with clinical outcome. Resolution of infiltrates may be slow, and the tendency for delayed clearing should be considered before initiating further invasive diagnostic investigation. Infections due to Tatlockia (Legionella) micdadei and Legionella bozemanii are more commonly reported in immunocompromised hosts; the radiographic manifestations are similar to those seen in Legionella pneumophila infection in the immunosuppressed.