scholarly journals Reporter Metabolite Analysis of Transcriptional Profiles of a Staphylococcus aureus Strain with Normal Phenotype and Its Isogenic hemB Mutant Displaying the Small-Colony-Variant Phenotype

2006 ◽  
Vol 188 (22) ◽  
pp. 7765-7777 ◽  
Author(s):  
Jochen Seggewiß ◽  
Karsten Becker ◽  
Oliver Kotte ◽  
Martin Eisenacher ◽  
Mohammad Reza Khoschkhoi Yazdi ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Dna Microarrays ◽  
Capsular Polysaccharide ◽  
Arginine Deiminase ◽  
Aureus Strain ◽  
Small Colony Variant ◽  
Normal Phenotype ◽  
Persistent Infections ◽  
Genome Wide ◽  
Small Colony

ABSTRACT In this study, full-genome DNA microarrays based on the sequence of Staphylococcus aureus N315 were used to compare the transcriptome of a clinical S. aureus strain with a normal phenotype to that of its isogenic mutant with a stable small-colony-variant (SCV) phenotype (hemB::ermB). In addition to standard statistical analyses, systems biology advances were applied to identify reporter metabolites and to achieve a more detailed survey of genome-wide expression differences between the hemB mutant and its parental strain. Genes of enzymes involved in glycolytic and fermentative pathways were found to be up-regulated in the hemB mutant. Furthermore, our analyses allowed identification of additional differences between the normal-phenotype S. aureus and the SCV, most of which were related to metabolism. Profound differences were identified especially in purine biosynthesis as well as in arginine and proline metabolism. Of particular interest, a hypothetical gene of the Crp/Fnr family (SA2424) that is part of the arginine-deiminase (AD) pathway, whose homologue in Streptococcus suis is assumed to be involved in intracellular persistence, showed significantly increased transcription in the hemB mutant. The hemB mutant potentially uses the up-regulated AD pathway to produce ATP or (through ammonia production) to counteract the acidic environment that prevails intracellularly. Moreover, genes involved in capsular polysaccharide and cell wall synthesis were found to be significantly up-regulated in the hemB mutant and therefore potentially responsible for the changed cell morphology of SCVs. In conclusion, the identified differences may be responsible for the SCV phenotype and its association with chronic and persistent infections.

scholarly journals Capsule Expression and Genotypic Differences among Staphylococcus aureus Isolates from Patients with Chronic or Acute Osteomyelitis

2009 ◽  
Vol 77 (5) ◽  
pp. 1968-1975 ◽  
Author(s):  
Santiago M. Lattar ◽  
Lorena P. N. Tuchscherr ◽  
Roberto L. Caccuri ◽  
Daniela Centrón ◽  
Karsten Becker ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Capsular Polysaccharide ◽  
Chronic Osteomyelitis ◽  
Phenotypic Expression ◽  
Genotypic Differences ◽  
Acute Osteomyelitis ◽  
Ample Evidence ◽  
Small Colony Variant ◽  
Small Colony ◽  
Relative Prevalence

ABSTRACT There is ample evidence that Staphylococcus aureus capsular polysaccharide (CP) promotes virulence. Loss of capsule expression, however, may lead to S. aureus persistence in a chronically infected host. This study was conducted to determine the relative prevalence of nonencapsulated S. aureus in patients with chronic and acute osteomyelitis. Only 76/118 (64%) S. aureus isolates from patients with osteomyelitis expressed CP, whereas all 50 isolates from blood cultures of patients with infections other than osteoarticular infections expressed CP (P = 0.0001). A significantly higher prevalence of nonencapsulated S. aureus was found in patients with chronic osteomyelitis (53%) than in those with acute osteomyelitis (21%) (P = 0.0046). S. aureus isolates obtained from multiple specimens from five of six patients with chronic osteomyelitis exhibited phenotypic (expression of CP, α-hemolysin, β-hemolysin, slime, and the small-colony variant phenotype) and/or genotypic (pulsed-field gel electrophoresis and spa typing) differences. Nonencapsulated S. aureus was recovered from at least one specimen from each chronic osteomyelitis patient. Fourteen isolates obtained from two patients with acute osteomyelitis were indistinguishable from each other within each group, and all produced CP5. In conclusion, we demonstrated that nonencapsulated S. aureus is more frequently isolated from patients with chronic osteomyelitis than from those with acute osteomyelitis, suggesting that loss of CP expression may be advantageous to S. aureus during chronic infection. Our findings on multiple S. aureus isolates from individual patients allow us to suggest that selection of nonencapsulated S. aureus is likely to have occurred in the patient during long-term bone infection.

scholarly journals Intracellular Activity of Antibiotics in a Model of Human THP-1 Macrophages Infected by a Staphylococcus aureus Small-Colony Variant Strain Isolated from a Cystic Fibrosis Patient: Pharmacodynamic Evaluation and Comparison with Isogenic Normal-Phenotype and Revertant Strains

2009 ◽  
Vol 53 (4) ◽  
pp. 1434-1442 ◽  
Author(s):  
Hoang Anh Nguyen ◽  
Olivier Denis ◽  
Anne Vergison ◽  
Anne Theunis ◽  
Paul M. Tulkens ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Staphylococcus Aureus ◽  
Cystic Fibrosis Patient ◽  
Similar Reduction ◽  
Small Colony Variant ◽  
Normal Phenotype ◽  
Intracellular Activity ◽  
Static Effect ◽  
Small Colony ◽  
Confocal And Electron Microscopy

ABSTRACT Small-colony variant (SCV) strains of Staphylococcus aureus show reduced antibiotic susceptibility and intracellular persistence, potentially explaining therapeutic failures. The activities of oxacillin, fusidic acid, clindamycin, gentamicin, rifampin, vancomycin, linezolid, quinupristin-dalfopristin, daptomycin, tigecycline, moxifloxacin, telavancin, and oritavancin have been examined in THP-1 macrophages infected by a stable thymidine-dependent SCV strain in comparison with normal-phenotype and revertant isogenic strains isolated from the same cystic fibrosis patient. The SCV strain grew slowly extracellularly and intracellularly (1- and 0.2-log CFU increase in 24 h, respectively). In confocal and electron microscopy, SCV and the normal-phenotype bacteria remain confined in acid vacuoles. All antibiotics tested, except tigecycline, caused a net reduction in bacterial counts that was both time and concentration dependent. At an extracellular concentration corresponding to the maximum concentration in human serum (total drug), oritavancin caused a 2-log CFU reduction at 24 h; rifampin, moxifloxacin, and quinupristin-dalfopristin caused a similar reduction at 72 h; and all other antibiotics had only a static effect at 24 h and a 1-log CFU reduction at 72 h. In concentration dependence experiments, response to oritavancin was bimodal (two successive plateaus of −0.4 and −3.1 log CFU); tigecycline, moxifloxacin, and rifampin showed maximal effects of −1.1 to −1.7 log CFU; and the other antibiotics produced results of −0.6 log CFU or less. Addition of thymidine restored intracellular growth of the SCV strain but did not modify the activity of antibiotics (except quinupristin-dalfopristin). All drugs (except tigecycline and oritavancin) showed higher intracellular activity against normal or revertant phenotypes than against SCV strains. The data may help rationalizing the design of further studies with intracellular SCV strains.

scholarly journals In VitroSusceptibility of ClinicalStaphylococcus aureusSmall-Colony Variants to β-Lactam and Non-β-Lactam Antibiotics

2018 ◽  
Vol 62 (4) ◽  
Author(s):  
Evgeny A. Idelevich ◽  
André Kriegeskorte ◽  
Nina Schleimer ◽  
Georg Peters ◽  
Christof von Eiff ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Prolonged Incubation ◽  
Content Type ◽  
Small Colony Variant ◽  
Normal Phenotype ◽  
Gradient Diffusion ◽  
Small Colony ◽  
Inhibition Zones

ABSTRACTTheStaphylococcus aureussmall-colony variant (SCV) phenotype has been associated with relapsing and antibiotic-refractory infections. However, little is known about the activities of antibiotics on clinical SCVs. Here, we demonstrated that SCVs without detectable auxotrophies were at least as susceptible to most β-lactam and non-β-lactam antibioticsin vitroas their corresponding clonally identical strains with a normal phenotype. After prolonged incubation, a regrowth phenomenon has been observed in gradient diffusion inhibition zones irrespective of the strains' phenotype.

scholarly journals Involvement of Small Colony Variant-Related Heme Biosynthesis Genes in Staphylococcus aureus Persister Formation in vitro

2021 ◽  
Vol 12 ◽  
Author(s):  
Xuyang Wang ◽  
Weizheng Li ◽  
Wenjie Wang ◽  
Shiyong Wang ◽  
Tao Xu ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Acid Stress ◽  
Heme Biosynthesis ◽  
Rna Seq ◽  
Small Colony Variant ◽  
Persistent Infections ◽  
Allelic Replacement ◽  
Small Colony ◽  
The Relationship

Background: Persisters are important reasons for persistent infections, and they can lead to antibiotic treatment failure in patients and consequently chronic infection. Staphylococcus aureus small colony variants (SCVs) have been shown to be related to persistent infection. Mutations in the genes of the heme biosynthesis pathway lead to the formation of SCVs. However, the relationship between heme production genes and persister has not been tested.Methods:HemA and hemB were knocked out by allelic replacement from S. aureus strain USA500 separately, and then, the heme deficiency was complemented by overexpression of related genes and the addition of hemin. The stress-related persister assay was conducted. RNA-sequencing was performed to find genes and pathways involved in heme-related persister formation, and relative genes and operons were further knocked out and overexpressed to confirm their role in each process.Results: We found that heme biosynthesis deficiency can lead to decreased persister. After complementing the corresponding genes or hemin, the persister levels could be restored. RNA-seq on knockout strains showed that various metabolic pathways were influenced, such as energy metabolism, amino acid metabolism, carbohydrate metabolism, and membrane transport. Overexpression of epiF and operon asp23 could restore USA500∆hemA persister formation under acid stress. Knocking out operon arc in USA500∆hemA could further reduce USA500∆hemA persister formation under acid and oxidative stress.Conclusion: Heme synthesis has a role in S. aureus persister formation.

scholarly journals Increased Expression of Clumping Factor and Fibronectin-Binding Proteins by hemB Mutants of Staphylococcus aureus Expressing Small Colony Variant Phenotypes

2002 ◽  
Vol 70 (10) ◽  
pp. 5428-5437 ◽  
Author(s):  
Pierre Vaudaux ◽  
Patrice Francois ◽  
Carmelo Bisognano ◽  
William L. Kelley ◽  
Daniel P. Lew ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Surface Display ◽  
Human Embryonic Kidney Cells ◽  
Small Colony Variant ◽  
Reverse Transcription Pcr ◽  
Bacterial Adhesins ◽  
Transport Chain ◽  
Complete Restoration ◽  
Small Colony ◽  
Slow Growing

ABSTRACT Small colony variants (SCVs) of Staphylococcus aureus are slow-growing subpopulations that cause persistent and relapsing infections. The altered phenotype of SCV can arise from defects in menadione or hemin biosynthesis, which disrupt the electron transport chain and decrease ATP concentrations. With SCVs, virulence is altered by a decrease in exotoxin production and susceptibility to various antibiotics, allowing their intracellular survival. The expression of bacterial adhesins by SCVs is poorly documented. We tested fibrinogen- and fibronectin-mediated adhesion of a hemB mutant of S. aureus 8325-4 that is defective for hemin biosynthesis and exhibits a complete SCV phenotype. In this strain, adhesion to fibrinogen and fibronectin was significantly higher than that of its isogenic, normally growing parent and correlated with the increased surface display of these adhesins as assessed by flow cytometry. Real-time quantitative reverse transcription-PCR demonstrated increased expression of clfA and fnb genes by the hemB mutant compared to its isogenic parent. The influence of the hemB mutation on altered adhesin expression was confirmed by showing complete restoration of the wild-type adhesive phenotype in the hemB mutant, either by complementing with intact hemB or by supplementing the growth medium with hemin. Increased surface display of fibrinogen and fibronectin adhesins by the hemB mutation occurred independently from agr, a major regulatory locus of virulence factors in S. aureus. Both agr-positive and agr-lacking hemB mutants were also more efficiently internalized by human embryonic kidney cells than were their isogenic controls, presumably because of increased surface display of their fibronectin adhesins.

SMALL COLONY VARIANT STAPHYLOCOCCUS AUREUS MULTIORGAN INFECTION

2007 ◽  
Vol 26 (3) ◽  
pp. 269-271 ◽  
Author(s):  
Hemant Agarwal ◽  
Rosemary Verrall ◽  
Sudha P. Singh ◽  
Yi-Wei Tang ◽  
Gregory Wilson
Keyword(s):  
Staphylococcus Aureus ◽  
Small Colony Variant ◽  
Small Colony

scholarly journals A site-directed Staphylococcus aureus hemB mutant is a small-colony variant which persists intracellularly.

1997 ◽  
Vol 179 (15) ◽  
pp. 4706-4712 ◽  
Author(s):  
C von Eiff ◽  
C Heilmann ◽  
R A Proctor ◽  
C Woltz ◽  
G Peters ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Small Colony Variant ◽  
Small Colony ◽  
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