scholarly journals High Levels of Genetic Recombination during Nasopharyngeal Carriage and Biofilm Formation in Streptococcus pneumoniae

mBio ◽  
2012 ◽  
Vol 3 (5) ◽  
Author(s):  
Laura R. Marks ◽  
Ryan M. Reddinger ◽  
Anders P. Hakansson
Keyword(s):  
Biofilm Formation ◽  
Transformation Efficiency ◽  
Genetic Exchange ◽  
Biofilm Growth ◽  
High Transformation ◽  
Lower Temperature ◽  
Multiple Strains

ABSTRACTTransformation of genetic material between bacteria was first observed in the 1920s usingStreptococcus pneumoniaeas a model organism. Since then, the mechanism of competence induction and transformation has been well characterized, mainly using planktonic bacteria or septic infection models. However, epidemiological evidence suggests that genetic exchange occurs primarily during pneumococcal nasopharyngeal carriage, which we have recently shown is associated with biofilm growth, and is associated with cocolonization with multiple strains. However, no studies to date have comprehensively investigated genetic exchange during cocolonizationin vitroandin vivoor the role of the nasopharyngeal environment in these processes. In this study, we show that genetic exchange during dual-strain carriagein vivois extremely efficient (10−2) and approximately 10,000,000-fold higher than that measured during septic infection (10−9). This high transformation efficiency was associated with environmental conditions exclusive to the nasopharynx, including the lower temperature of the nasopharynx (32 to 34°C), limited nutrient availability, and interactions with epithelial cells, which were modeled in a novel biofilm modelin vitrothat showed similarly high transformation efficiencies. The nasopharyngeal environmental factors, combined, were critical for biofilm formation and induced constitutive upregulation of competence genes and downregulation of capsule that promoted transformation. In addition, we show that dual-strain carriagein vivoand biofilms formedin vitrocan be transformed during colonization to increase their pneumococcal fitness and also, importantly, that bacteria with lower colonization ability can be protected by strains with higher colonization efficiency, a process unrelated to genetic exchange.IMPORTANCEAlthough genetic exchange between pneumococcal strains is known to occur primarily during colonization of the nasopharynx and colonization is associated with biofilm growth, this is the first study to comprehensively investigate transformation in this environment and to analyze the role of environmental and bacterial factors in this process. We show that transformation efficiency during cocolonization by multiple strains is very high (around 10−2). Furthermore, we provide novel evidence that specific aspects of the nasopharyngeal environment, including lower temperature, limited nutrient availability, and epithelial cell interaction, are critical for optimal biofilm formation and transformation efficiency and result in bacterial protein expression changes that promote transformation and fitness of colonization-deficient strains. The results suggest that cocolonization in biofilm communities may have important clinical consequences by facilitating the spread of antibiotic resistance and enabling serotype switching and vaccine escape as well as protecting and retaining poorly colonizing strains in the pneumococcal strain pool.

scholarly journals Candida albicans forms biofilms on the vaginal mucosa

Microbiology ◽  
2010 ◽  
Vol 156 (12) ◽  
pp. 3635-3644 ◽  
Author(s):  
M. M. Harriott ◽  
E. A. Lilly ◽  
T. E. Rodriguez ◽  
P. L. Fidel ◽  
M. C. Noverr
Keyword(s):  
Biofilm Formation ◽  
Ex Vivo ◽  
Microscopic Analysis ◽  
Vaginal Mucosa ◽  
First Time ◽  
Established Role ◽  
Type Strains

Current understanding of resistance and susceptibility to vulvovaginal candidiasis challenges existing paradigms of host defence against fungal infection. While abiotic biofilm formation has a clearly established role during systemic Candida infections, it is not known whether C. albicans forms biofilms on the vaginal mucosa and the possible role of biofilms in disease. In vivo and ex vivo murine vaginitis models were employed to examine biofilm formation by scanning electron and confocal microscopy. C. albicans strains included 3153A (lab strain), DAY185 (parental control strain), and mutants defective in morphogenesis and/or biofilm formation in vitro (efg1/efg1 and bcr1/bcr1). Both 3153A and DAY815 formed biofilms on the vaginal mucosa in vivo and ex vivo as indicated by high fungal burden and microscopic analysis demonstrating typical biofilm architecture and presence of extracellular matrix (ECM) co-localized with the presence of fungi. In contrast, efg1/efg1 and bcr1/bcr1 mutant strains exhibited weak or no biofilm formation/ECM production in both models compared to wild-type strains and complemented mutants despite comparable colonization levels. These data show for the first time that C. albicans forms biofilms in vivo on vaginal epithelium, and that in vivo biotic biofilm formation requires regulators of biofilm formation (BCR1) and morphogenesis (EFG1).

scholarly journals Function of BriC Peptide in the Pneumococcal Competence and Virulence Portfolio

2018 ◽  
Author(s):  
Surya D. Aggarwal ◽  
Rory Eutsey ◽  
Jacob West-Roberts ◽  
Arnau Domenech ◽  
Wenjie Xu ◽  
...  
Keyword(s):  
Murine Model ◽  
Biofilm Formation ◽  
Opportunistic Pathogen ◽  
Nasopharyngeal Colonization ◽  
Point Of Entry ◽  
Abiotic Surfaces ◽  
Biofilm Development

AbstractStreptococcus pneumoniae (pneumococcus) is an opportunistic pathogen that causes otitis media, sinusitis, pneumonia, meningitis and sepsis. The progression to this pathogenic lifestyle is preceded by asymptomatic colonization of the nasopharynx. This colonization is associated with biofilm formation; the competence pathway influences the structure and stability of biofilms. However, the molecules that link the competence pathway to biofilm formation are unknown. Here, we describe a new competence-induced gene, called briC, and demonstrate that its product promotes biofilm development and stimulates colonization in a murine model. We show that expression of briC is induced by the master regulator of competence, ComE. Whereas briC does not substantially influence early biofilm development on abiotic surfaces, it significantly impacts later stages of biofilm development. Specifically, briC expression leads to increases in biofilm biomass and thickness at 72h. Consistent with the role of biofilms in colonization, briC promotes nasopharyngeal colonization in the murine model. The function of BriC appears to be conserved across pneumococci, as comparative genomics reveal that briC is widespread across isolates. Surprisingly, many isolates, including strains from clinically important PMEN1 and PMEN14 lineages, which are widely associated with colonization, encode a long briC promoter. This long form captures an instance of genomic plasticity and functions as a competence-independent expression enhancer that may serve as a precocious point of entry into this otherwise competence-regulated pathway. Moreover, overexpression of briC by the long promoter fully rescues the comE-deletion induced biofilm defect in vitro, and partially in vivo. These findings indicate that BriC may bypass the influence of competence in biofilm development and that such a pathway may be active in a subset of pneumococcal lineages. In conclusion, BriC is a part of the complex molecular network that connects signaling of the competence pathway to biofilm development and colonization.

scholarly journals Streptolysin-induced endoplasmic reticulum stress promotes group A streptococcal in vivo biofilm formation and necrotizing fasciitis

2017 ◽  
Author(s):  
Anuradha Vajjala ◽  
Debabrata Biswas ◽  
Kelvin Kian Long Chong ◽  
Wei Hong Tay ◽  
Emanuel Hanski ◽  
...  
Keyword(s):  
Soft Tissue ◽  
Er Stress ◽  
Necrotizing Fasciitis ◽  
Biofilm Formation ◽  
Mammalian Cells ◽  
Chronic Infections ◽  
Group A

AbstractGroup A Streptococcus (GAS) is a human pathogen that causes infections ranging from mild to fulminant and life-threatening. Biofilms have been implicated in acute GAS soft-tissue infections such as necrotizing fasciitis (NF). However, most in vitro models used to study GAS biofilms have been designed to mimic chronic infections and insufficiently recapitulate in vivo conditions and the host-pathogen interactions that might influence biofilm formation. Here we establish and characterize an in vitro model of GAS biofilm development on mammalian cells that simulates microcolony formation observed in a murine model of human NF. We show that on mammalian cells, GAS forms dense aggregates that display hallmark biofilm characteristics including a three-dimensional architecture and enhanced tolerance to antibiotics. In contrast to abiotic-grown biofilms, host-associated biofilms require the expression of secreted GAS streptolysins O and S (SLO, SLS) resulting in the release of a host-associated biofilm promoting-factor(s). Supernatants from GAS-infected mammalian cells or from cells treated with endoplasmic reticulum (ER) stressors restore biofilm formation to an SLO and SLS null mutant that is otherwise attenuated in biofilm formation on cells, together suggesting a role for streptolysin-induced ER stress in this process. In an in vivo mouse model, the streptolysin-null mutant is attenuated in both microcolony formation and bacterial spread, but pre-treatment of softtissue with an ER-stressor restores the ability of the mutant to form wild type like microcolonies that disseminate throughout the soft tissue. Taken together, we have identified a new role of streptolysin-driven ER stress in GAS biofilm formation and NF disease progression.Significance StatementAlthough it is well-accepted that bacterial biofilms are associated with many chronic infections, little is known about the mechanisms by which group A Streptococcus (GAS) biofilms contribute to acute soft tissue-invasive diseases like necrotizing fasciitis (NF). In this study, we establish a physiologically relevant in vitro model to study GAS biofilm formation on mammalian cells and validate our findings in a mouse model that mimics human NF. This study demonstrates a novel role of GAS streptolysin-mediated ER stress in the development and spread of GAS biofilms in acute softtissue infections. We also show that biofilm formation depends on the release of a host-associated factor that promotes microcolony formation and GAS dissemination in vivo.

scholarly journals Effect of Simulated Gastrointestinal Conditions on Biofilm Formation bySalmonella1,4,[5],12:i:-

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
R. Seixas ◽  
M. Gabriel ◽  
J. Machado ◽  
L. Tavares ◽  
F. Bernardo ◽  
...  
Keyword(s):  
Gastrointestinal Tract ◽  
Biofilm Formation ◽  
Contributing Factors ◽  
Biofilm Growth ◽  
Biofilm Production ◽  
Gastrointestinal Conditions ◽  
Mueller Hinton ◽  
Mueller Hinton Broth

SalmonellaTyphimurium 1,4,[5],12:i:- is a major serovar responsible for human salmonellosis whose biofilm-forming ability, influenced by environmental conditions like those found in the gastrointestinal tract, is one of the main contributing factors to its ability to persist in the host and thus one of the main causes of chronic relapsing infections. Most studies to evaluate biofilm formation are performed in microtiter assays using standard media. However, no reports are available on the ability of this serovar to produce biofilm underin vitrosimulated gastrointestinal conditions which better correlate with the environment found in the gastrointestinal tract. To address this, a modified biofilm assay simulating intestinal fluid was conceived to assess the biofilm formation of 133SalmonellaTyphimurium 1,4,[5],12:i:- isolates with and without agitation and at three different time points (24 h, 48 h, and 72 h). The results were then compared to the existing microtiter method using conventional biofilm growth medium (Mueller Hinton Broth). Statistical analysis revealed significant differences in the results obtained between the three protocols used. The simulated human intestinal environment impaired biofilm production demonstrating that conditions like pH, agitation or the presence of enzymes can influence biofilm production. Therefore, results fromin vitrosimulation ofin vivoconditions may contribute to unravelling factors relating to biofilm formation and persistence in the context of the human host.

scholarly journals Biofilm Formation by and Thermal Niche and Virulence Characteristics of Escherichia spp.

2011 ◽  
Vol 77 (8) ◽  
pp. 2695-2700 ◽  
Author(s):  
Danielle J. Ingle ◽  
Olivier Clermont ◽  
David Skurnik ◽  
Erick Denamur ◽  
Seth T. Walk ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Content Type ◽  
E Coli ◽  
Phylogenetic Affiliation ◽  
Class 1 ◽  
Extraintestinal Disease ◽  
Maximal Growth Rate ◽  
Lower Temperature

ABSTRACTIn order to better understand the ecological and virulence characteristics of the various clades ofEscherichia,in vitroandin vivoexperiments were undertaken. Members of the recently described cryptic clades ofEscherichia(clades III, IV, and V) were found to have an enhanced ability to form biofilms compared to strains ofEscherichia coli,E. fergusonii, orE. albertii. Members of the cryptic clades were also able to replicate at a lower temperature (5°C versus 11°C) than strains of the named species ofEscherichia. Neither a strain's maximal growth rate nor its optimal temperature for growth varied with respect to the strain's phylogenetic affiliation.Escherichiastrains not belonging to the speciesE. coliwere positive for a mix of traits thought to enhance a strain's ability to cause either intestinal or extraintestinal disease. However, no non-E. coliEscherichiastrain was virulent in a mouse model of extraintestinal infection. The frequency of resistance to antibiotics was low, and none of the strains tested harbored class 1, 2, or 3 integrons. The results of these experiments support the hypothesis that members of the crypticEscherichiaclades may be better able to persist in the external environment compared toE. coli,E. fergusonii, orE. albertii, isolates.

scholarly journals Streptococcus pyogenes Biofilm Growth In Vitro and In Vivo and Its Role in Colonization, Virulence, and Genetic Exchange

2014 ◽  
Vol 210 (1) ◽  
pp. 25-34 ◽  
Author(s):  
Laura R. Marks ◽  
Lauren Mashburn-Warren ◽  
Michael J. Federle ◽  
Anders P. Hakansson
Keyword(s):  
Streptococcus Pyogenes ◽  
Genetic Exchange ◽  
Biofilm Growth

scholarly journals Evaluation of a Tetracycline-Inducible Promoter inStaphylococcus aureus In Vitro and In Vivo and Its Application in Demonstrating the Role of sigB in Microcolony Formation

2001 ◽  
Vol 69 (12) ◽  
pp. 7851-7857 ◽  
Author(s):  
B. T. Bateman ◽  
N. P. Donegan ◽  
T. M. Jarry ◽  
M. Palma ◽  
A. L. Cheung
Keyword(s):  
Biofilm Formation ◽  
Genetic Basis ◽  
Inducible Promoter ◽  
Inducible Systems ◽  
Tetracycline Induction ◽  
Dose Dependent ◽  
Promoter System

ABSTRACT An inducible promoter system provides a powerful tool for studying the genetic basis for virulence. A variety of inducible systems have been used in other organisms, including pXyl-xylR-inducible promoter, the pSpac-lacI system, and the arabinose-inducible PBAD promoter, but each of these systems has limitations in its application to Staphylococcus aureus. In this study, we demonstrated the efficacy of a tetracycline-inducible promoter system in inducing gene expression in S. aureus in vitro and inside epithelial cells as well as in an animal model of infection. Using the xyl/tetOpromoter::gfp uvr fusion carried on a shuttle plasmid, we demonstrated that dose-dependant tetracycline induction, as measured by bacterial fluorescence, occurred in each of the above environments while basal activation under noninduced conditions remained low. To ascertain how the system can be used to elucidate the genetic basis of a pathogenic phenotype, we cloned thesigB gene downstream of the inducible promoter. Induction of SigB expression led to dose-dependent attachment of the tested strain to polystyrene microtiter wells. Additionally, bacterial microcolony formation, an event preceding mature biofilm formation, also increased with tetracycline induction of SigB.

scholarly journals A counter-enzyme complex regulates glutamate metabolism in Bacillus subtilis

2021 ◽  
Author(s):  
Vijay Jayaraman ◽  
D. John Lee ◽  
Nadav Elad ◽  
Shay Vimer ◽  
Michal Sharon ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Glutamate Synthase ◽  
Enzyme Complex ◽  
Primary Role ◽  
Biofilm Growth ◽  
Rich Media ◽  
Sequential Reactions

Multi-enzyme assemblies composed of metabolic enzymes catalyzing sequential reactions are being increasingly studied. Here, we report the discovery of a 1.6 megadalton multi-enzyme complex from Bacillus subtilis composed of two enzymes catalyzing opposite rather than sequential reactions (counter-enzymes): glutamate synthase (GltAB), and glutamate dehydrogenase (GudB), that make and break glutamate, respectively. In vivo and in vitro studies show that the primary role of complex formation is to inhibit GudBs activity as this enzyme is constitutively expressed including in glutamate-limiting conditions. Using cryo-electron microscopy, we elucidated the structure of the complex and the basis of GudBs inhibition. Finally, we show that this complex that exhibits unusual oscillatory progress curves is a necessity for planktonic growth in glutamate-limiting conditions, but is also essential for biofilm growth in glutamate-rich media, suggesting a regulatory role at fluctuating glutamate concentrations.

scholarly journals Assessment of Ceragenins in Prevention of Damage to Voice Prostheses Caused by Candida Biofilm Formation

Pathogens ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1371
Author(s):  
Jakub Spałek ◽  
Tamara Daniluk ◽  
Adrian Godlewski ◽  
Piotr Deptuła ◽  
Urszula Wnorowska ◽  
...  
Keyword(s):  
Candida Species ◽  
Biofilm Formation ◽  
Significant Proportion ◽  
Life Quality ◽  
Ethanol Solution ◽  
In Vivo Studies ◽  
Biofilm Growth ◽  
Voice Prostheses

This study aimed to investigate the potential application of ceragenins (CSAs) as new candidacidal agents to prevent biofilm formation on voice prostheses (VPs). The deterioration of the silicone material of VPs is caused by biofilm growth on the device which leads to frequent replacement procedures and sometimes serious complications. A significant proportion of these failures is caused by Candida species. We found that CSAs have significant candidacidal activities in vitro (MIC; MFC; MBIC), and they effectively eradicate species of yeast responsible for VP failure. Additionally, in our in vitro experimental setting, when different Candida species were subjected to CSA-13 and CSA-131 during 25 passages, no tested Candida strain showed the significant development of resistance. Using liquid chromatography–mass spectrometry (LC-MS), we found that VP immersion in an ethanol solution containing CSA-131 results in silicon impregnation with CSA-131 molecules, and in vitro testing revealed that fungal biofilm formation on such VP surfaces was inhibited by embedded ceragenins. Future in vivo studies will validate the use of ceragenin-coated VP for improvement in the life quality and safety of patients after a total laryngectomy.

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