Intracellular survival of Burkholderia cepacia complex isolates in the presence of macrophage cell activation

Saini, Lalit; Galsworthy, S. B.; John, Michael; Valvano, Miguel A.

doi:10.1099/00221287-145-12-3465

Cited by 108 publications

(137 citation statements)

References 54 publications

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“…The capacity of Bcc strains to survive and replicate within eukaryotic cells may explain their persistence in the respiratory system . However, the replication ability of Burkholderia inside cell lines is known to vary between isolates or genomovars (Saini et al, 1999;Sajjan et al, 2006). In this study we showed that both B. ambifaria HSJ1 wild-type and variant can replicate within phagosomes, but HSJ1v clearly displayed reduced replication in the human monocyte cell line compared with HSJ1.…”

Section: Features Of B Ambifaria Clinical Isolatesmentioning

confidence: 61%

“…Direct evidence of intracellular survival of the Bcc species has been shown in airway epithelial cells, in murine macrophages, in human monocytic cells and in amoebae (Marolda et al, 1999;Saini et al, 1999;Savoia and Zucca, 2007). The capacity of Bcc strains to survive and replicate within eukaryotic cells may explain their persistence in the respiratory system .…”

Section: Features Of B Ambifaria Clinical Isolatesmentioning

confidence: 99%

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Phase variation has a role in Burkholderia ambifaria niche adaptation

et al. 2009

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Members of the Burkholderia cepacia complex (Bcc), such as B. ambifaria, are effective biocontrol strains, for instance, as plant growth-promoting bacteria; however, Bcc isolates can also cause severe respiratory infections in people suffering from cystic fibrosis (CF). No distinction is known between isolates from environmental and human origins, suggesting that the natural environment is a potential source of infectious Bcc species. While investigating the presence and role of phase variation in B. ambifaria HSJ1, an isolate recovered from a CF patient, we identified stable variants that arose spontaneously irrespective of the culture conditions. Phenotypic and proteomic approaches revealed that the transition from wild-type to variant types affects the expression of several putative virulence factors. By using four different infection models (Drosophila melanogaster, Galleria mellonella, macrophages and Dictyostelium discoideum), we showed that the wild-type was more virulent than the variant. It may be noted that the variant showed reduced replication in a human monocyte cell line when compared with the wild-type. On the other hand, the variant of isolate HSJ1 was more competitive in colonizing plant roots than the wild-type. Furthermore, we observed that only clinical B. ambifaria isolates generated phase variants, and that these variants showed the same phenotypes as observed with the HSJ1 variant. Finally, we determined that environmental B. ambifaria isolates showed traits that were characteristic of variants derived from clinical isolates. Our study therefore suggest that B. ambifaria uses phase variation to adapt to drastically different environments: the lung of patients with CF or the rhizosphere.

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Section: Features Of B Ambifaria Clinical Isolatesmentioning

confidence: 61%

Section: Features Of B Ambifaria Clinical Isolatesmentioning

confidence: 99%

Phase variation has a role in Burkholderia ambifaria niche adaptation

et al. 2009

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“…In addition, B. cepacia complex strains can survive within a murine macrophage cell line in the presence of an oxidative burst, and reduced nitric oxide production (Saini et al, 1999). These observations suggest that bacterial resistance or adaptation to oxidative damage may play a role in the infectivity and persistence of B. cepacia complex strains within the airways of patients with cystic fibrosis (Valvano et al, 2005).…”

Section: Introductionmentioning

confidence: 75%

“…Previously, we have shown that B. cepacia complex strains can survive intracellularly in both macrophages and amoebae (Lamothe et al, 2004;Marolda et al, 1999;Saini et al, 1999). In addition, B. cepacia complex strains can survive within a murine macrophage cell line in the presence of an oxidative burst, and reduced nitric oxide production (Saini et al, 1999).…”

Section: Introductionmentioning

confidence: 99%

A minor catalase/peroxidase from Burkholderia cenocepacia is required for normal aconitase activity

2005

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The opportunistic bacterium Burkholderia cenocepacia C5424 contains two catalase/peroxidase genes, katA and katB. To investigate the functions of these genes, katA and katB mutants were generated by targeted integration of suicide plasmids into the katA and katB genes. The catalase/peroxidase activity of the katA mutant was not affected as compared with that of the parental strain, while no catalase/peroxidase activity was detected in the katB mutant. However, the katA mutant displayed reduced resistance to hydrogen peroxide under iron limitation, while the katB mutant showed hypersensitivity to hydrogen peroxide, and reduced growth under all conditions tested. The katA mutant displayed reduced growth only in the presence of carbon sources that are metabolized through the tricarboxylic acid (TCA) cycle, as the growth defect was abrogated in cultures supplemented with glucose or glycerol. This phenotype was also correlated with a marked reduction in aconitase activity. In contrast, aconitase activity was not reduced in the katB mutant and parental strains. The authors conclude that the KatA protein is a specialized catalase/peroxidase that has a novel function by contributing to maintain the normal activity of the TCA cycle, while KatB is a classical catalase/peroxidase that plays a global role in cellular protection against oxidative stress.

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“…Recent studies showed that B. cepacia is capable of survival and growth within free-living amoebae, indicating that amoebae may be a reservoir for B. cepacia in the environment [26,27]. The mechanism by which B. cepacia survives in amoebae and pulmonary macrophages might be similar [16]. Furthermore, the pathogenic potential of B. cepacia for non-CF patients has been illustrated in patients with chronic granulomatous disease.…”

Section: Discussionmentioning

confidence: 99%

Invasion of murine respiratory epithelial cells in vivo by Burkholderia cepacia

Ostry

2001

Journal of Medical Microbiology

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Pulmonary infections caused by Burkholderia cepacia are an important cause of morbidity and mortality in cystic ®brosis (CF) patients. Several features suggestive of invasion and intracellular sequestration of B. cepacia in CF are persistence of infection in the face of antibiotic therapy and a propensity to cause bacteraemic infections in patients with CF. A mouse respiratory challenge model was used to investigate the invasion phenotype of B. cepacia in vivo. After intratracheal inoculation, epidemic B. cepacia strains translocated from lung to liver and spleen; however, all bacteria were cleared from all organs within 7 days. B. cepacia strains, irrespective of cable piliation, were capable of attaching to and then invading murine respiratory tract epithelial cells. Histopathological examination of lungs showed interstitial in®ltrates comprised mainly of polymorphonuclear leucocytes and were associated with widened alveolar septa. Electron microscopy demonstrated B. cepacia within epithelial cells and pulmonary macrophages. This study provides support for in-vitro observations that B. cepacia strains from patients with CF adhere to and then invade respiratory epithelial cells. The invasion phenotype in B. cepacia may be an important virulence factor in CF infections.

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Intracellular survival of Burkholderia cepacia complex isolates in the presence of macrophage cell activation

Cited by 108 publications

References 54 publications

Phase variation has a role in Burkholderia ambifaria niche adaptation

Phase variation has a role in Burkholderia ambifaria niche adaptation

A minor catalase/peroxidase from Burkholderia cenocepacia is required for normal aconitase activity

Invasion of murine respiratory epithelial cells in vivo by Burkholderia cepacia

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