scholarly journals Coagulase-negative staphylococci release a purine analog that inhibits Staphylococcus aureus virulence

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Denny Chin ◽  
Mariya I. Goncheva ◽  
Ronald S. Flannagan ◽  
Shayna R. Deecker ◽  
Veronica Guariglia-Oropeza ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Ribosomal Proteins ◽  
De Novo ◽  
Toxin Production ◽  
Skin Lesions ◽  
Purine Biosynthesis ◽  
Coagulase Negative Staphylococcus ◽  
Accessory Gene ◽  
Coagulase Negative Staphylococci ◽  
Purine Analog

AbstractCoagulase-negative staphylococci and Staphylococcus aureus colonize similar niches in mammals and conceivably compete for space and nutrients. Here, we report that a coagulase-negative staphylococcus, Staphylococcus chromogenes ATCC43764, synthesizes and secretes 6-thioguanine (6-TG), a purine analog that suppresses S. aureus growth by inhibiting de novo purine biosynthesis. We identify a 6-TG biosynthetic gene cluster in S. chromogenes and other coagulase-negative staphylococci including S. epidermidis, S. pseudintermedius and S. capitis. Recombinant S. aureus strains harbouring this operon produce 6-TG and, when used in subcutaneous co-infections in mice with virulent S. aureus USA300, protect the host from necrotic lesion formation. Used prophylactically, 6-TG reduces necrotic skin lesions in mice infected with USA300, and this effect is mediated by abrogation of toxin production. RNAseq analyses reveal that 6-TG downregulates expression of genes coding for purine biosynthesis, the accessory gene regulator (agr) and ribosomal proteins in S. aureus, providing an explanation for its effect on toxin production.

scholarly journals Mutations in a membrane permease or hpt lead to 6-thioguanine resistance in Staphylococcus aureus

2021 ◽  
Author(s):  
Denny Chin ◽  
Mariya I. Goncheva ◽  
Ronald S. Flannagan ◽  
David E. Heinrichs
Keyword(s):  
Staphylococcus Aureus ◽  
De Novo ◽  
Toxin Production ◽  
Lesion Size ◽  
Missense Mutations ◽  
Nucleotide Polymorphisms ◽  
Coagulase Negative Staphylococci ◽  
Evolution Of Resistance ◽  
High Concentrations

We recently discovered that 6-thioguanine (6-TG) is an anti-virulence compound that is produced by a number of coagulase negative staphylococci. In Staphylococcus aureus , it inhibits de novo purine biosynthesis and ribosomal protein expression, thus inhibiting growth and abrogating toxin production. Mechanisms by which S. aureus may develop resistance to this compound are currently unknown. Here, we show that 6-TG-resistant S. aureus mutants emerge spontaneously when the bacteria are subjected to high concentrations of 6-TG in vitro . Whole genome sequencing of these mutants revealed frameshift and missense mutations in a xanthine-uracil permease family protein ( stgP : s ix t hio g uanine p ermease) and single nucleotide polymorphisms in hypoxanthine phosphoribosyltransferase ( hpt ). These mutations engender S. aureus the ability to resist both the growth inhibitory and toxin down regulation effects of 6-TG. While prophylactic administration of 6-TG ameliorates necrotic lesions in subcutaneous infection of mice with MRSA strain USA300-LAC, the drug did not reduce lesion size formed by the 6-TG resistant strains. These findings identify mechanisms of 6-TG resistance and this information can be leveraged to inform strategies to slow the evolution of resistance.

scholarly journals Activity of Debio1452, a FabI Inhibitor with Potent Activity against Staphylococcus aureus and Coagulase-Negative Staphylococcus spp., Including Multidrug-Resistant Strains

2015 ◽  
Vol 59 (5) ◽  
pp. 2583-2587 ◽  
Author(s):  
Robert K. Flamm ◽  
Paul R. Rhomberg ◽  
Nachum Kaplan ◽  
Ronald N. Jones ◽  
David J. Farrell
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Agents ◽  
Fatty Acid Biosynthesis ◽  
Multidrug Resistant ◽  
Coagulase Negative Staphylococcus ◽  
Significant Activity ◽  
Coagulase Negative Staphylococci ◽  
Content Type ◽  
Mrsa Strains ◽  
Human Infections

ABSTRACTStaphylococcus aureusand coagulase-negative staphylococci (CoNS) are responsible for a wide variety of human infections. The investigational antibacterial Debio1450 (previously AFN-1720), a prodrug of Debio1452 (previously AFN-1252), specifically targets staphylococci without significant activity against other Gram-positive or Gram-negative species. Debio1452 inhibits FabI, an enzyme critical to fatty acid biosynthesis in staphylococci. The activity of Debio1452 against CoNS, methicillin-susceptibleS. aureus(MSSA), and methicillin-resistantS. aureus(MRSA), including significant clones, was determined. A globally diverse collection of 574 patient isolates from 35 countries was tested that included CoNS (6 species, 103 strains), MSSA (154 strains), MRSA (163 strains), and molecularly characterized strains (includingspa-typed MRSA clones; 154 strains). The isolates were tested for susceptibility by CLSI broth microdilution methods against Debio1452 and 10 comparators. The susceptibility rates for the comparators were determined using CLSI and EUCAST breakpoint criteria. AllS. aureusand CoNS strains were inhibited by Debio1452 concentrations of ≤0.12 and ≤0.5 μg/ml, respectively. The MIC50s for MSSA, MRSA, and molecularly characterized MRSA strains were 0.004 μg/ml, and the MIC90s ranged from 0.008 to 0.03 μg/ml. The MICs were higher for the CoNS isolates (MIC50/90, 0.015/0.12 μg/ml). AmongS. aureusstrains, resistance was common for erythromycin (61.6%), levofloxacin (49.0%), clindamycin (27.6%), tetracycline (15.7%), and trimethoprim-sulfamethoxazole (7.0%). Debio1452 demonstrated potent activity against MSSA, MRSA, and CoNS. Debio1452 showed significantly greater activity overall (MIC50, 0.004 μg/ml) than the other agents tested against these staphylococcal species, which included dominant MRSA clones and strains resistant to currently utilized antimicrobial agents.

scholarly journals De Novo Purine Biosynthesis Is Required for Intracellular Growth of Staphylococcus aureus and for the Hypervirulence Phenotype of a purR Mutant

2020 ◽  
Vol 88 (5) ◽  
Author(s):  
Mariya I. Goncheva ◽  
Ronald S. Flannagan ◽  
David E. Heinrichs
Keyword(s):  
Staphylococcus Aureus ◽  
Virulence Factors ◽  
Metabolic Regulation ◽  
De Novo ◽  
Purine Biosynthesis ◽  
Mammalian Host ◽  
Cell Binding ◽  
Intracellular Growth ◽  
Content Type ◽  
De Novo Purine Biosynthesis

ABSTRACT Staphylococcus aureus is a noted human and animal pathogen. Despite decades of research on this important bacterium, there are still many unanswered questions regarding the pathogenic mechanisms it uses to infect the mammalian host. This can be attributed to it possessing a plethora of virulence factors and complex virulence factor and metabolic regulation. PurR, the purine biosynthesis regulator, was recently also shown to regulate virulence factors in S. aureus, and mutations in purR result in derepression of fibronectin binding proteins (FnBPs) and extracellular toxins, required for a so-called hypervirulent phenotype. Here, we show that hypervirulent strains containing purR mutations can be attenuated with the addition of purine biosynthesis mutations, implicating the necessity for de novo purine biosynthesis in this phenotype and indicating that S. aureus in the mammalian host experiences purine limitation. Using cell culture, we showed that while purR mutants are not altered in epithelial cell binding, compared to that of wild-type (WT) S. aureus, purR mutants have enhanced invasion of these nonprofessional phagocytes, consistent with the requirement of FnBPs for invasion of these cells. This correlates with purR mutants having increased transcription of fnb genes, resulting in higher levels of surface-exposed FnBPs to promote invasion. These data provide important contributions to our understanding of how the pathogenesis of S. aureus is affected by sensing of purine levels during infection of the mammalian host.

scholarly journals Right-sided endocarditis from Staphylococcus lugdunensis in a patient with tetralogy of Fallot

2019 ◽  
Vol 11 (1) ◽  
Author(s):  
Bradford III Becken ◽  
Jacob Kilgore ◽  
Elizabeth Thompson ◽  
M. Anthony Moody
Keyword(s):  
Staphylococcus Aureus ◽  
Infective Endocarditis ◽  
Tetralogy Of Fallot ◽  
Pediatric Patients ◽  
Coagulase Negative Staphylococcus ◽  
Coagulase Negative Staphylococci ◽  
Staphylococcus Lugdunensis ◽  
Enterococcal Species ◽  
Viridans Group Streptococci ◽  
Culture Negative

Infective endocarditis is often caused by bacterial pathogens and can affect native and prosthetic tissue. Common pathogens in pediatric patients include Staphylococcus aureus, viridans group streptococci, enterococcal species and coagulase-negative staphylococci, though culture-negative cases are not uncommon. Coagulase-negative staphylococci present a conundrum to clinicians due to the potential of culture contamination. While Staphylococcus lugdunensis is a coagulase-negative staphylococcus, it is an emerging cardiotropic pathogen that presents similarly to Staphylococcus aureus. Here we report a case of a child with repaired tetralogy of Fallot found to have right-sided infective endocarditis caused by Staphylococcus lugdunensis.

scholarly journals Linezolid Surveillance Results for the United States (LEADER Surveillance Program 2014)

2016 ◽  
Vol 60 (4) ◽  
pp. 2273-2280 ◽  
Author(s):  
Robert K. Flamm ◽  
Rodrigo E. Mendes ◽  
Patricia A. Hogan ◽  
Jennifer M. Streit ◽  
James E. Ross ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Streptococcus Pneumoniae ◽  
Ribosomal Proteins ◽  
The United States ◽  
23S Rrna ◽  
Surveillance Program ◽  
Coagulase Negative Staphylococci ◽  
Content Type ◽  
Mrsa Strains ◽  
Viridans Group Streptococci

ABSTRACTThelinezolidexperience andaccuratedetermination ofresistance (LEADER) surveillance program has monitored linezolid activity, spectrum, and resistance since 2004. In 2014, a total of 6,865 Gram-positive pathogens from 60 medical centers from 36 states were submitted. The organism groups evaluated wereStaphylococcus aureus(3,106), coagulase-negative staphylococci (CoNS; 797), enterococci (855),Streptococcus pneumoniae(874), viridans group streptococci (359), and beta-hemolytic streptococci (874). Susceptibility testing was performed by reference broth microdilution at the monitoring laboratory. Linezolid-resistant isolates were confirmed by repeat testing. PCR and sequencing were performed to detect mutations in 23S rRNA, L3, L4, and L22 proteins and acquired genes (cfrandoptrA). The MIC50/90forStaphylococcus aureuswas 1/1 μg/ml, with 47.2% of isolates being methicillin-resistantStaphylococcus aureus. Linezolid was active against allStreptococcus pneumoniaestrains and beta-hemolytic streptococci with a MIC50/90of 1/1 μg/ml and against viridans group streptococci with a MIC50/90of 0.5/1 μg/ml. Among the linezolid-nonsusceptible MRSA strains, one strain harboredcfronly (MIC, 4 μg/ml), one harbored G2576T (MIC, 8 μg/ml), and one containedcfrand G2576T with L3 changes (MIC, ≥8 μg/ml). Among CoNS, 0.75% (six isolates) of all strains demonstrated linezolid MIC results of ≥4 μg/ml. Five of these were identified asStaphylococcus epidermidis, four of which containedcfrin addition to the presence of mutations in the ribosomal proteins L3 and L4, alone or in combination with 23S rRNA (G2576T) mutations. Six enterococci (0.7%) were linezolid nonsusceptible (≥4 μg/ml; five with G2576T mutations, including one with an additionalcfrgene, and one strain withoptrAonly). Linezolid demonstrated excellent activity and a sustained susceptibility rate of 99.78% overall.

Effect of Borate on the Growth of Coagulase-Positive and Coagulase-Negative Staphylococci

1970 ◽  
Vol 1 (1) ◽  
pp. 78-79
Author(s):  
James M. Jay
Keyword(s):  
Staphylococcus Aureus ◽  
Food Poisoning ◽  
Toxin Production ◽  
Sodium Borate ◽  
Coagulase Negative Staphylococci

Of 235 strains of coagulase-positive Staphylococcus aureus studied, 221 or 94% were inhibited by 1.5 × 10 −8 m sodium borate, whereas only 6 of 57 (10.5%) coagulase-negative strains were inhibited by the same borate concentration. Four of the six coagulase-negatives were food poisoning strains and one was a hospital pathogen. Borate sensitivity was found to correlate well with lysozyme and α-toxin production by coagulase-positive strains.

scholarly journals Staphylococcus chromogenes, a Coagulase-Negative Staphylococcus Species That Can Clot Plasma

2016 ◽  
Vol 54 (5) ◽  
pp. 1372-1375 ◽  
Author(s):  
Danielle Cabral dos Santos ◽  
Carla Christine Lange ◽  
Pedro Avellar-Costa ◽  
Katia Regina Netto dos Santos ◽  
Maria Aparecida Vasconcelos Paiva Brito ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Dairy Cows ◽  
Coagulase Negative Staphylococcus ◽  
Coagulase Negative Staphylococci ◽  
Content Type

Staphylococcus chromogenesis one of the main coagulase-negative staphylococci isolated from mastitis of dairy cows. We describeS. chromogenesisolates that can clot plasma. Since the main pathogen causing mastitis is coagulase-positiveStaphylococcus aureus, the coagulase-positive phenotype ofS. chromogenesdescribed here can easily lead to misidentification.

scholarly journals Biofilm Formation by Staphylococcus aureus Clinical Isolates is Differentially Affected by Glucose and Sodium Chloride Supplemented Culture Media

2019 ◽  
Vol 8 (11) ◽  
pp. 1853 ◽  
Author(s):  
Harshad Lade ◽  
Joon Hyun Park ◽  
Sung Hee Chung ◽  
In Hee Kim ◽  
Jung-Min Kim ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Sodium Chloride ◽  
Biofilm Formation ◽  
Culture Media ◽  
Toxin Production ◽  
Culture Conditions ◽  
Clinical Isolates ◽  
Accessory Gene ◽  
Methicillin Resistant

Staphylococcus aureus (S. aureus) causes persistent biofilm-related infections. Biofilm formation by S. aureus is affected by the culture conditions and is associated with certain genotypic characteristics. Here, we show that glucose and sodium chloride (NaCl) supplementation of culture media, a common practice in studies of biofilms in vitro, influences both biofilm formation by 40 S. aureus clinical isolates (methicillin-resistant and methicillin-sensitive S. aureus) and causes variations in biofilm quantification. Methicillin-resistant strains formed more robust biofilms than methicillin-sensitive strains in tryptic soy broth (TSB). However, glucose supplementation in TSB greatly promoted and stabilized biofilm formation of all strains, while additional NaCl was less efficient in this respect and resulted in significant variation in biofilm measurements. In addition, we observed that the ST239-SCCmec (Staphylococcal Cassette Chromosome mec) type III lineage formed strong biofilms in TSB supplemented with glucose and NaCl. Links between biofilm formation and accessory gene regulator (agr) status, as assessed by δ-toxin production, and with mannitol fermentation were not found. Our results show that TSB supplemented with 1.0% glucose supports robust biofilm production and reproducible quantification of S. aureus biofilm formation in vitro, whereas additional NaCl results in major variations in measurements of biofilm formation.

scholarly journals Quorum Sensing and Toxin Production in Staphylococcus aureus Osteomyelitis: Pathogenesis and Paradox

Toxins ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 516
Author(s):  
Casey E. Butrico ◽  
James E. Cassat
Keyword(s):  
Staphylococcus Aureus ◽  
Quorum Sensing ◽  
Toxin Production ◽  
High Morbidity ◽  
Invasive Infection ◽  
Accessory Gene ◽  
Accessory Gene Regulator ◽  
Production Factors ◽  
Regulatory Systems ◽  
Skeletal Homeostasis

Staphylococcus aureus is a Gram-positive pathogen capable of infecting nearly every vertebrate organ. Among these tissues, invasive infection of bone (osteomyelitis) is particularly common and induces high morbidity. Treatment of osteomyelitis is notoriously difficult and often requires debridement of diseased bone in conjunction with prolonged antibiotic treatment to resolve infection. During osteomyelitis, S. aureus forms characteristic multicellular microcolonies in distinct niches within bone. Virulence and metabolic responses within these multicellular microcolonies are coordinated, in part, by quorum sensing via the accessory gene regulator (agr) locus, which allows staphylococcal populations to produce toxins and adapt in response to bacterial density. During osteomyelitis, the Agr system significantly contributes to dysregulation of skeletal homeostasis and disease severity but may also paradoxically inhibit persistence in the host. Moreover, the Agr system is subject to complex crosstalk with other S. aureus regulatory systems, including SaeRS and SrrAB, which can significantly impact the progression of osteomyelitis. The objective of this review is to highlight Agr regulation, its implications on toxin production, factors that affect Agr activation, and the potential paradoxical influences of Agr regulation on disease progression during osteomyelitis.

scholarly journals The de novo Purine Biosynthesis Pathway Is the Only Commonly Regulated Cellular Pathway during Biofilm Formation in TSB-Based Medium in Staphylococcus aureus and Enterococcus faecalis

2021 ◽  
Keyword(s):  
Staphylococcus Aureus ◽  
Enterococcus Faecalis ◽  
Biofilm Formation ◽  
De Novo ◽  
Purine Biosynthesis ◽  
Biosynthesis Pathway ◽  
Chronic Infections ◽  
De Novo Purine Biosynthesis ◽  
Cellular Pathways ◽  
Different Strains

Bacterial biofilms are involved in chronic infections and confer 10 to 1,000 times more resistance to antibiotics compared with planktonic growth, leading to complications and treatment failure. When transitioning from a planktonic lifestyle to biofilms, some Gram-positive bacteria are likely to modulate several cellular pathways, including central carbon metabolism, biosynthesis pathways, and production of secondary metabolites. These metabolic adaptations might play a crucial role in biofilm formation by Gram-positive pathogens such as Staphylococcus aureus and Enterococcus faecalis. Here, we performed a transcriptomic approach to identify cellular pathways that might be similarly regulated during biofilm formation in these bacteria. Different strains and biofilm-inducing media were used to identify a set of regulated genes that are common and independent of the environment or accessory genomes analyzed. Our approach highlighted that the de novo purine biosynthesis pathway was upregulated in biofilms of both species when using a tryptone soy broth-based medium but not so when a brain heart infusion-based medium was used. We did not identify other pathways commonly regulated between both pathogens. Gene deletions and usage of a drug targeting a key enzyme showed the importance of this pathway in biofilm formation of S. aureus. The importance of the de novo purine biosynthesis pathway might reflect an important need for purine during biofilm establishment, and thus could constitute a promising drug target. IMPORTANCE Biofilms are often involved in nosocomial infections and can cause serious chronic infections if not treated properly. Current anti-biofilm strategies rely on antibiotic usage, but they have a limited impact because of the biofilm intrinsic tolerance to drugs. Metabolism remodeling likely plays a central role during biofilm formation. Using comparative transcriptomics of different strains of Staphylococcus aureus and Enterococcus faecalis, we determined that almost all cellular adaptations are not shared between strains and species. Interestingly, we observed that the de novo purine biosynthesis pathway was upregulated during biofilm formation by both species in a specific medium. The requirement for purine could constitute an interesting new anti-biofilm target with a wide spectrum that could also prevent resistance evolution. These results are also relevant to a better understanding of the physiology of biofilm formation.

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