False positive Legionella pneumophila direct immunofluorescent monoclonal antibody test caused by Bacillus cereus spores

Flournoy, D. J.; Belobraydic, K.A.; Silberg, Stanley L.; Lawrence, Charles H.; Guthrie, P.J.

doi:10.1016/0732-8893(88)90106-x

Cited by 19 publications

(3 citation statements)

References 5 publications

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“…Although L. pneumophila does not form spores in any of its life stages, a legionella-specific monoclonal antibody has been reported to cross-react with spores but not vegetative cells of the gram-positive bacterium Bacillus cereus (23). While difficult to interpret, this observation may indicate that some unusual antigens of L. pneumophila may be functionally similar to components of gram-positive spores.…”

Section: Discussionmentioning

confidence: 65%

Ultrastructural Analysis of Differentiation in Legionella pneumophila

Faulkner¹,

Garduño

2002

J Bacteriol

107

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Legionella pneumophila is an adaptive pathogen that replicates in the intracellular environment of fundamentally divergent hosts (freshwater protozoa and mammalian cells) and is capable of surviving long periods of starvation in water when between hosts. Physiological adaptation to these quite diverse environments seems to be accompanied by morphological changes (Garduño et al., p. 82-85, in Marre et al., ed., Legionella, 2001) and conceivably involves developmental differentiation. In following the fine-structural pathway of L. pneumophila through both in vitro and in vivo growth cycles, we have now discovered that this bacterium displays an unprecedented number of morphological forms, as revealed in ultrathin sections and freeze-fracture replicas for transmission electron microscopy. Many of the forms were identified by the obvious ultrastructural properties of their cell envelope, which included changes in the relative opaqueness of membrane leaflets, vesiculation, and/or profuse invagination of the inner membrane. These changes were best documented with image analysis software to obtain intensity tracings of the envelope in cross sections. Also prominent were changes in the distribution of intramembranous particles (clearly revealed in replicas of freeze-fractured specimens) and the formation of cytoplasmic inclusions. Our results confirm that L. pneumophila is a highly pleomorphic bacterium and clarify some early observations suggesting sporogenic differentiation in L. pneumophila. Since morphological changes occurred in a conserved sequence within the growth cycle, our results also provide strong evidence for the existence of a developmental cycle in L. pneumophila that is likely accompanied by profound physiological alterations and stage-specific patterns of gene expression.Legionella pneumophila is a gram-negative bacterial pathogen that has evolved to replicate in the intracellular compartment of freshwater amoebae (3, 9, 21). Accidentally, L. pneumophila infects the alveolar macrophages of susceptible humans and causes the atypical pneumonia known as Legionnaires' disease. The intracellular environment not only represents a survival haven for L. pneumophila but also seems to be essential for replication, implying that, in spite of its ability to grow in artificial media in the laboratory, L. pneumophila is a natural obligate intracellular pathogen (3,20,21). After egressing from a wasted host, extracellular L. pneumophila survives extended periods of starvation in fresh water (45,58,60), perhaps in a nonculturable form (61), until it finds a new protozoan host.Central to the pathogenesis and ecology of obligate intracellular bacterial pathogens with an extracellular phase (wellstudied examples being Chlamydia and Coxiella spp.) is the ability to differentiate into various forms within a developmental cycle (35,36,46,48,49,57). Typically, after or during their intracellular replication, these pathogens differentiate into a highly infectious and environmentally resilient form that survives extracellularl...

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Section: Discussionmentioning

confidence: 65%

Ultrastructural Analysis of Differentiation in Legionella pneumophila

Faulkner¹,

Garduño

2002

J Bacteriol

107

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“…This reagent is highly specific for L. pneumophila strains, making it possible to confirm isolates belonging to this species. It should be noted that a cross-reaction with Bacillus cereus spores from a strain isolated from water has been reported (99). However, this organism is easy to differentiate from Legionella in pure culture.…”

Section: Dfa Detection Of Legionellamentioning

confidence: 99%

Legionella and Legionnaires' Disease: 25 Years of Investigation

2002

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There is still a low level of clinical awareness regarding Legionnaires' disease 25 years after it was first detected. The causative agents, legionellae, are freshwater bacteria with a fascinating ecology. These bacteria are intracellular pathogens of freshwater protozoa and utilize a similar mechanism to infect human phagocytic cells. There have been major advances in delineating the pathogenesis of legionellae through the identification of genes which allow the organism to bypass the endocytic pathways of both protozoan and human cells. Other bacteria that may share this novel infectious process are Coxiella burnetti and Brucella spp. More than 40 species and numerous serogroups of legionellae have been identified. Most diagnostic tests are directed at the species that causes most of the reported human cases of legionellosis, L. pneumophila serogroup 1. For this reason, information on the incidence of human respiratory disease attributable to other species and serogroups of legionellae is lacking. Improvements in diagnostic tests such as the urine antigen assay have inadvertently caused a decrease in the use of culture to detect infection, resulting in incomplete surveillance for legionellosis. Large, focal outbreaks of Legionnaires' disease continue to occur worldwide, and there is a critical need for surveillance for travel-related legionellosis in the United States. There is optimism that newly developed guidelines and water treatment practices can greatly reduce the incidence of this preventable illness

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“…The sensitivity of direct immunofluorescent antibody (DFA) testing performed with the commercial monoclonal anti-L. pneumophila antibody is similar to that of polyclonal reagents (Edelstein et al 1985), but the specificity is higher (Tenoveretal. 1986, Edelstein & Edelstein 1989), reflected in the very few examples of non-immune binding published (Staphylococcus aureus, Bacillus cereus spores (Flournoy et al 1988), both of which should pose no diagnostic problems). The greatest risk of acquiring a false-positive reaction with DFA emerges by contamination of the slides (Ristagno & Saravolatz 1985).…”

Section: Direct Methodsmentioning

confidence: 99%

Antigenic and genetic characterization of Leaionella Proteins: Contribution to taxonomy, diagnosis and pathogenesis

Bangsborg

1997

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False positive Legionella pneumophila direct immunofluorescent monoclonal antibody test caused by Bacillus cereus spores

Cited by 19 publications

References 5 publications

Ultrastructural Analysis of Differentiation in Legionella pneumophila

Ultrastructural Analysis of Differentiation in Legionella pneumophila

Legionella and Legionnaires' Disease: 25 Years of Investigation

Antigenic and genetic characterization of Leaionella Proteins: Contribution to taxonomy, diagnosis and pathogenesis

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