Persistent Legionella pneumophila bacteraemia in an immunocompromised host

Marrie, Thomas J.; Martín, R

doi:10.1016/s0163-4453(88)94222-3

Cited by 8 publications

(12 citation statements)

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“…Human disease occurs when aerosolized L. pneumophila is inhaled from man-made or natural freshwater reservoirs harboring the bacteria. L. pneumophila poses a significant worldwide public health problem, particularly for individuals with compromised immune systems (19,38,40). Eradication of the pathogen from freshwater, industrial settings has proven difficult, since L. pneumophila thrives in environments that exclude antibacterial agents, such as biofilms and the intracellular compartments of protozoa (8,46,47).…”

mentioning

confidence: 99%

Evidence for Acquisition ofLegionellaType IV Secretion Substrates via Interdomain Horizontal Gene Transfer

Felipe

Pampou

Jovanovic³

et al. 2005

J Bacteriol

255

316

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Intracellular pathogens exploit host cell functions to create a replication niche inside eukaryotic cells. The causative agent of Legionnaires' disease, the ␥-proteobacterium Legionella pneumophila, resides and replicates within a modified vacuole of protozoan and mammalian cells. L. pneumophila translocates effector proteins into host cells through the Icm-Dot complex, a specialized type IVB secretion system that is required for intracellular growth. To find out if some effector proteins may have been acquired through interdomain horizontal gene transfer (HGT), we performed a bioinformatic screen that searched for eukaryotic motifs in all open reading frames of the L. pneumophila Philadelphia-1 genome. We found 44 uncharacterized genes with many distinct eukaryotic motifs. Most of these genes contain G؉C biases compared to other L. pneumophila genes, supporting the theory that they were acquired through HGT. Furthermore, we found that several of them are expressed and up-regulated in stationary phase in an RpoS-dependent manner. In addition, at least seven of these gene products are translocated into host cells via the Icm-Dot complex, confirming their role in the intracellular environment. Reminiscent of the case with most Icm-Dot substrates, most of the strains containing mutations in these genes grew comparably to the parent strain intracellularly. Our findings suggest that in L. pneumophila, interdomain HGT may have been a major mechanism for the acquisition of determinants of infection.The ␥-proteobacterium Legionella pneumophila is an opportunistic human pathogen that multiplies within alveolar macrophages and causes the nosocomial and community-acquired pneumonia known as Legionnaires' disease (18,25,48). Human disease occurs when aerosolized L. pneumophila is inhaled from man-made or natural freshwater reservoirs harboring the bacteria. L. pneumophila poses a significant worldwide public health problem, particularly for individuals with compromised immune systems (19,38,40). Eradication of the pathogen from freshwater, industrial settings has proven difficult, since L. pneumophila thrives in environments that exclude antibacterial agents, such as biofilms and the intracellular compartments of protozoa (8,46,47).In order to create a replicative niche inside eukaryotic cells suitable for replication, L. pneumophila is believed to modulate host cell functions by the delivery of effector proteins through a type IVB secretion system known as the Icm-Dot complex (52, 59). Effector proteins presumably regulate several pathways in the host, including up-regulation of phagocytosis (23), delay in phagosome-lysosome fusion (24), recruitment of ARF1 to the phagosome (43), acquisition of endoplasmic reticulum-derived vesicles (29), and nonlytic egress from the host cell (11).Several laboratories found Icm-Dot substrates through genetic screens and bioinformatic approaches (3,7,11,13,36,43,44,57). Most of the known effector proteins are not individually required for intracellular multiplication, since knocking out th...

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confidence: 99%

Evidence for Acquisition ofLegionellaType IV Secretion Substrates via Interdomain Horizontal Gene Transfer

Felipe

Pampou

Jovanovic³

et al. 2005

J Bacteriol

255

316

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“…Corticosteroid administration and other illnesses associated with immunosuppression are also independent risk factors [1,6]. LD with bacteremia has been rarely reported in patients with protein-losing enteropathy [2], acquired immunodeficiency syndrome (AIDS) [3], Goodpasture's syndrome [4], and underlying malignancy [5]. The impaired cell-mediated immunity, related to steroid therapy and underlying autoimmune disorder, probably predisposed our patient to the development of LD with bacteremia.…”

Section: Discussionmentioning

confidence: 99%

“…The diagnosis of Legionella infection in our patient was confirmed by positive blood culture and urine antigen assay, not by sputum culture and elevation of serum antibody titer. Nevertheless, the isolation of Legionella from blood such as in our patient is very rare [2][3][4][5], and culture is still the most specific technique and is widely accepted as the standard diagnostic method. Previous studies demonstrated that the isolation of L. pneumophila was obtained from both aerobic and anaerobic bottles.…”

Section: Discussionmentioning

confidence: 99%

“…Although diagnostic methods have improved since L. pneumophila was first described in 1976, culture remains the gold standard for the diagnosis of LD. Culture-proven legionellosis is rarely diagnosed, and reports of LD with bacteremia are extremely rare [2][3][4][5]. We describe the first reported blood culture-proven case of L. pneumophila pneumonia from Taiwan in a patient receiving corticosteroids.…”

Section: Introductionmentioning

confidence: 99%

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Hospital-Acquired Pneumonia and Bacteremia Caused by Legionella pneumophila in an Immunocompromised Patient

et al. 2010

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The Legionella species is an important cause of communityand hospital-acquired pneumonia. Bacteremic pneumonia caused by L. pneumophila is rarely reported. We describe the first reported case of hospital-acquired pneumonia and bacteremia caused by L. pneumophila from Taiwan in a patient with idiopathic thrombocytopenic purpura who received steroid treatment. The patient was successfully treated with ceftazidime and clindamycin initially, followed by ciprofloxacin for 14 days. The blood isolate was further confirmed by 16S rDNA sequence analysis.

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“…There have not been many documented cases of Legionella bacteremia. Single isolations have been reported by using biphasic blood culture media and supplemented proteose peptone broth (45,101,105,106). The BACTEC 460 instrument recovered isolates variably: in one study, aerobic 6B bottles were positive by growth index and subculture whereas the anaerobic 7D bottles were negative (32); in another study, the 7D bottles were positive by blind subculture whereas the aerobic bottles were negative (145).…”

Section: Rare and Fastidious Organismsmentioning

confidence: 99%