Lung abscess caused by Legionella micdadei

Percutaneous transthoracic catheter drainage for lung abscess: a systematic review and meta-analysis

OBJECTIVES

To evaluate the outcomes of patients receiving image-guided percutaneous catheter drainage (PCD) for lung abscesses in terms of treatment success, major complications, and mortality as well as the predictors of those outcomes.

METHODS

Embase and OVID-MEDLINE databases were searched to identify studies on lung abscesses treated with PCD that had extractable outcomes. The outcomes were pooled using a random-intercept logistic regression model. Multivariate Firth's bias-reduced penalised-likelihood logistic regression analyses were performed to identify predictors of treatment success and complications. Methodological quality was assessed by summing scores of binary responses to items regarding selection, ascertainment of exposure and outcome, causality of follow-up duration, and reporting.

RESULTS

From 26 studies with acceptable methodological quality (median score, 4; range, 3-5), 194 patients were included. The pooled rates of treatment success and major complications were 86.5% (95% confidence interval [CI], 78.5-91.8%; I² = 23%) and 8.1% (95% CI, 4.1-15.3%; I² = 26%), respectively. Four patients eventually died from uncontrolled lung abscesses (pooled rate, 1.5%; 95% CI, 0.2-11.1%; I² = 36%). Malignancy-related abscess (odds ratio [OR], 0.129; 95% CI, 0.024-0.724; p = .022) and the occurrence of a major complication (OR, 0.065; 95% CI, 0.02-0.193; p < .001) were significant predictors of treatment failure. Traversing normal lung parenchyma was the only significant risk factor for major complications (OR, 27.69; 95% CI, 7.196-123.603; p < .001).

CONCLUSION

PCD under imaging guidance was effective for lung abscess treatment, with a low complication rate. Traversal of normal lung parenchyma was the sole risk factor for complications, and malignancy-related abscesses and the occurrence of major complications were predictors of treatment failure.

KEY POINTS

• The pooled treatment success rate of PCD for lung abscess was reasonably high (86.5%); malignancy-related abscesses and the occurrence of a major complication were predictors of treatment failure. • The pooled rate of percutaneous transthoracic catheter drainage-related major complications was 8.1% and traversing normal lung parenchyma by the catheter was the only risk factor. • The pooled mortality rate from uncontrolled lung abscesses with percutaneous transthoracic catheter drainage was low.

Legionella pulmonary abscess and pleural space infection in an immunocompetent patient

A 34-year-old woman is admitted to the hospital with dyspnoea, dry cough and left-sided flank pain. Her Legionella urinary test was positive and CT imaging demonstrated multifocal pneumonia with pulmonary abscesses. Although she had initial clinical improvement on appropriate antibiotic therapy, her hospital course was complicated by worsening flank pain, hypoxemia and leucocytosis, prompting clinical re-evaluation and assessment for development of complications involving the pleural space. CT imaging revealed interval development of a loculated complicated parapneumonic effusion. Successful treatment required chest tube drainage assisted by fibrinolytic therapy. This case highlights the importance of considering Legionella in patients with pulmonary abscess, demonstrates an approach to a patient with a non-resolving pneumonia and illustrates the management of parapneumonic effusions.

Mistaken identity: Legionella micdadei appearing as acid-fast bacilli on lung biopsy of a hematopoietic stem cell transplant patient

Legionella micdadei is a potential cause of invasive lung infections in immunocompromised hosts. On biopsy specimens, it can appear as an acid-fast bacillus (AFB) and can be mistaken for a member of genus Mycobacterium. As Legionella requires selective media to grow in culture, and the commonly used, commercially available urine antigen test for Legionella only detects Legionella pneumophila serogroup-1, but not L. micdadei, it is important to consider this organism in the differential diagnosis for AFB in immunocompromised hosts. We report a case of L. micdadei infection, which was initially treated empirically for non-tuberculous mycobacteria based on AFB staining of biopsy tissue before the final diagnosis was made.

An update on the drainage of pyogenic lung abscesses

Most lung abscesses (80-90%) are now successfully treated with antibiotics; however, this conservative approach may occasionally fail. When medical treatment fails, pulmonary resection is usually advised. Alternatively, percutaneous transthoracic tube drainage or endoscopic drainage can be considered, though both remain controversial. In this communication, the medical literature focusing on percutaneous tube drainage efficacy, indications, techniques, complications, and mortality, as well as available data regarding endoscopic drainage are reviewed.

Lung abscess caused by Legionella species: implication of the immune status of hosts

Legionella pneumonia typically presents as lobar pneumonia with multiple-lobe involvement, but Legionella lung abscess is rare. To identify the predisposing factors for Legionella abscess, we analyzed 62 of the 79 case reports on Legionella abscess found in literature; 28 (45.2%) were of hospital-acquired infection and 28 (45.2%), community-acquired infection. Seventeen patients (27.4%) died. L. pneumophila serogroup 1 was the most common, but other serogroups of L. pneumophila, L. micdadei, L. bozemanii, L. dumoffii, and L. maceachernii were also isolated from the abscess. Corticosteroids were administered for underlying diseases to 43 (69.4%) patients. Peripheral neutrophil counts were higher in patients with abscess than in those with only pulmonary infiltration. In certain cases, Legionella abscess developed during neutropenia recovery. However, lymphocyte counts were low in most cases. Clinical factors like corticosteroid treatment, which causes impaired cellular immunity and subsequent neutrophil accumulation in the lesion, might function as predisposing factors for Legionella abscess.

Legionella pneumonia and HIV: case reports and review of the literature

Although Legionnaires' disease occurs more commonly in patients with some degree of immunosuppression (diabetes, chronic lung disease, end stage renal disease, cancer, etc.), it has been infrequently described in patients infected with human immunodeficiency virus (HIV) and AIDS. Some studies suggest that pneumonia caused by Legionella tends to present with more severe clinical features and complications in the HIV-infected population. The use of antibiotic prophylaxis or the association of severe pneumonia with other pathogens may account for under diagnosis of the disease. We diagnosed five cases of Legionella pneumonia in patients with HIV infection at our institution during a 1-year period. The cases seen ranged in severity, regardless of the CD4(+) counts of the patients. Based on our observations, it seems impossible to discern whether HIV infection is an additional risk factor for Legionnaires' disease. We describe those five cases and review the available literature.

Community-acquired lung abscess caused by Legionella micdadei in a myeloma patient receiving thalidomide treatment

Legionella infection causes 2 to 14% of community-acquired pneumonia (CAP). Legionella micdadei constitutes <1% of these infections. We describe a case of cavitary L. micdadei CAP in a myeloma patient receiving thalidomide treatment. The importance of considering pneumonia and problems in diagnosing pneumonia caused by L. micdadei in this patient population are reviewed.

Legionelosis e infección por el virus de la inmunodeficiencia humana: ¿infección oportunista?

BACKGROUND AND OBJECTIVE

Legionella infections are not frequent in HIV-infected patients, although clinical manifestations and outcome are particularly severe in this subset. This manuscript analyzes the clinical features and immunological situation of HIV-infected patients with Legionnaires' disease (LD).

PATIENTS AND METHOD

The clinical files of HIV-infected patients diagnosed with LD from 1983 to December 2003 were reviewed. The incidence of hospital-acquired Legionella pneumonia (HALP) from 1997-2000 in HIV-infected patients was compared with that of non infected patients.

RESULTS

Eighteen patients were included. 72.2% were diagnosed by the Legionella urinary antigen assay. The incidence of HALP in HIV-infected and non infected patients was 0.3 and 0.25/1000 admissions/year, respectively (p = 0.42). 83.3% received appropriate antibiotic treatment at the Emergency department. The mean lymphocyte CD4 count was 348.1/microl, 53.8% had an undetectable viral load and 64.7% were on antiretroviral therapy. 72.2% were smokers, 38.8% had cancer and 16.7% were on chemotherapy. 93.8% had cough, 75% dyspnea, 62.5% extrarespiratory symptoms, 76.5% increased AST, 50% increased CK and 56.3% hyponatremia. Moreover, 50% developed bilateral pulmonary infiltrates, 83.3% respiratory failure and 22.2% died.

CONCLUSIONS

Although LD is not more frequent in HIV-infected than in non infected patients, its clinical severity suggests that it is an opportunistic infection.

Percutaneous drainage of pyogenic lung abscess

Although lung abscesses are successfully treated with antibiotics in 80-90% of cases, this conservative approach may occasionally fail. In cases of failure, pulmonary resection is usually advised. Although it remains controversial, an alternative therapy in such situations is percutaneous transthoracic tube drainage (PTTD). Herein we review the medical literature on PTTD from the last 25 y, focusing on its efficacy, indications, technique, complications and mortality. We conclude that PTTD is a safe, simple and efficacious tool for the management of refractory lung abscess. Complications relating to the procedure occurred in 9.7% of cases and included catheter occlusion, chest pain, pneumothorax and hemothorax. The overall mortality rate secondary to lung abscess was acceptable (4.8%).

Extrapulmonary Legionella micdadei infection in a previously healthy child

A previously healthy 9-year-old girl presented with a 1-week history of left neck mass and low grade fever. Surgical drainage specimens from the mass were bacterial culture-negative. Legionella micdadei infection was diagnosed by a two step PCR-nucleic acid sequencing method and supported by organism-specific serology. A backyard hot tub was suspected as the source of infection.

Infection due to Legionella species other than L. pneumophila

In addition to Legionella pneumophila, 19 Legionella species have been documented as human pathogens on the basis of their isolation from clinical material. Like L. pneumophila, other Legionella species are inhabitants of natural and man-made aqueous environments. The major clinical manifestation of infection due to Legionella species is pneumonia, although nonpneumonic legionellosis (Pontiac fever) and extrapulmonary infection may occur. The majority of confirmed infections involving non-pneumophila Legionella species have occurred in immunosuppressed patients. Definitive diagnosis requires culture on selective media. Fluoroquinolones and newer macrolides are effective therapy. A number of nosocomial cases have occurred in association with colonization of hospital water systems; elimination of Legionella species from such systems prevents their transmission to susceptible patients. It is likely that many cases of both community-acquired and nosocomial Legionella infection remain undiagnosed. Application of appropriate culture methodology to the etiologic diagnosis of pneumonia is needed to further define the role of these organisms in disease in humans.

Evaluation of detection of Legionella spp. in water samples by fluorescence in situ hybridization, PCR amplification and bacterial culture

One hundred water samples (32 from clinical units and 68 from private households) were examined for Legionella by culture, fluorescence in situ hybridization (FISH) and polymerase chain reaction (PCR). Twenty-four samples were positive by culture (22 L. pneumophila; 2 non-pneumophila species), 36 by FISH (32 L. pneumophila; 4 non-pneumophila species) and 75 by PCR (41 positive for L. pneumophila; 26 positive for L. pneumophila and a non-pneumophila species; 8 positive for non-pneumophila species). PCR and FISH results were compared to bacterial culture as the "gold standard" method by calculating sensitivities and specificities, respectively: PCR assays, 96% and 47%; FISH assays, 67% and 72%, respectively. In comparison with FISH the lower specificity of PCR is probably caused by dead Legionella bacteria and/or free Legionella DNA in potable water, and the higher sensitivity of PCR may be explained by the detection limit of fluorescence microscopy. In conclusion, the relatively high specificity, sensitivity and quickness of the FISH assay offer significant advantages over conventional PCR and culture-based techniques.

Pyogenic lung infections

Pyogenic lung infections still occur despite the availability of effective antibiotics for the treatment of patients with acute bacterial pneumonia. Our understanding of the pathogenesis and management of these conditions has steadily improved over the past few decades, although some areas remain obscure. The effect of HIV infection on the incidence of pyogenic lung infections remains largely unknown, and large studies are required to evaluate this. Burkholderia (formerly Pseudomonas) cepacia strains are now recognized as important respiratory pathogens in patients with cystic fibrosis, and the high transmissibility of some strains, combined with their inherent multiple antibiotic resistance, are continuing causes for concern.

Lung abcess complicating Legionella micdadei pneumonia in an adult liver transplant recipient: case report and review

Legionella micdadei (Pittsburgh pneumonia agent) is the second most common cause of Legionella pneumonia, and occurs predominantly in immunocompromised hosts. L micdadei is the cause of nosocomial pneumonia in renal transplant recipients, but has not been described in other adult solid organ transplant recipients. This report describes the first case of L micdadei pneumonia in an adult liver transplant recipient on immunosuppressive therapy. Importantly, this case highlights the difficulties in establishing the diagnosis, as the Legionella urinary antigen is negative, and special culture conditions are required. Furthermore, this case illustrates several atypical clinical features of L micdadei pneumonia in a transplant recipient, including a community acquired mode of transmission, occurrence several years after organ transplantation, and lung abcess formation. The patient was successfully treated with limited surgical resection and quinolone antimicrobial monotherapy.