Vancomycin and Daptomycin Pharmacodynamics Differ against a Site-Directed Staphylococcus epidermidis Mutant Displaying the Small-Colony-Variant Phenotype

ABSTRACT Catheter-related bloodstream infections due to slow-growing Staphylococcus epidermidis small-colony variants (SCVs) are extremely difficult to treat. Daptomycin and vancomycin pharmacodynamics were evaluated against a site-directed hemB mutant of S. epidermidis displaying the SCV phenotype and compared to that of the parental strain. The maximal killing effect decreased by 7.7-fold for vancomycin and 1.5-fold for daptomycin against the SCV mutant and were well characterized by a Hill-type mathematical model (R 2 > 0.97).

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

Infection and Immunity ◽

10.1128/iai.70.10.5428-5437.2002 ◽

2002 ◽

Vol 70 (10) ◽

pp. 5428-5437 ◽

Cited By ~ 120

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.

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Intraphagolysosomal conditions predispose to Staphylococcus epidermidis small colony variants persistence in macrophages

PLoS ONE ◽

10.1371/journal.pone.0207312 ◽

2018 ◽

Vol 13 (11) ◽

pp. e0207312 ◽

Cited By ~ 2

Author(s):

Agnieszka Magryś ◽

Kamil Deryło ◽

Agnieszka Bogut ◽

Alina Olender ◽

Marek Tchórzewski

Keyword(s):

Staphylococcus Epidermidis ◽

Small Colony Variants ◽

Small Colony

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

Journal of Bacteriology ◽

10.1128/jb.179.15.4706-4712.1997 ◽

1997 ◽

Vol 179 (15) ◽

pp. 4706-4712 ◽

Cited By ~ 213

Author(s):

C von Eiff ◽

C Heilmann ◽

R A Proctor ◽

C Woltz ◽

G Peters ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Small Colony Variant ◽

Small Colony ◽

A Site

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Characterization of Staphylococcus epidermidis and Staphyloccocus warneri small-colony variants associated with prosthetic-joint infections

Journal of Medical Microbiology ◽

10.1099/jmm.0.066068-0 ◽

2014 ◽

Vol 63 (2) ◽

pp. 176-185 ◽

Cited By ~ 17

Author(s):

Agnieszka Bogut ◽

Justyna Niedźwiadek ◽

Maria Kozioł-Montewka ◽

Dagmara Strzelec-Nowak ◽

Jan Blacha ◽

...

Keyword(s):

Antimicrobial Susceptibility ◽

Staphylococcus Epidermidis ◽

Hip Prosthesis ◽

Joint Infection ◽

Coagulase Negative Staphylococci ◽

Sensitivity Testing ◽

Small Colony Variants ◽

Prosthetic Joint ◽

Prosthetic Joint Infections ◽

Small Colony

We determined the frequency of isolation of staphylococcal small-colony variants (SCVs) from 31 culture-positive patients undergoing revision of total hip prosthesis for aseptic loosening or presumed prosthetic-joint infection (PJI). We analysed auxotrophy of cultured SCVs, their antimicrobial susceptibility profiles and their biofilm-forming capacity. Eight SCV strains were cultivated from six (19 %) patients. All SCVs were coagulase-negative staphylococci (CNS) with Staphylococcus epidermidis as the predominant species; there was also one Staphylococcus warneri SCV. The SCVs were auxotrophic for haemin, with one strain additionally auxotrophic for menadione. We noted the presence of two phenotypically (differences concerning antimicrobial susceptibility) and genetically distinct SCV strains in one patient, as well as the growth of two genetically related SCVs that differed in terms of their morphology and the type of auxotrophy in another. Seven out of eight SCVs were resistant to meticillin and gentamicin. In addition, antibiotic sensitivity testing revealed three multidrug-resistant SCV–normal-morphology isolate pairs. One S. epidermidis SCV harboured icaADBC genes and was found to be a proficient biofilm producer. This paper highlights the involvement of CNS SCVs in the aetiology of PJIs, including what is believed to be the first report of a S. warneri SCV. These subpopulations must be actively sought in the routine diagnosis of implant-associated infections. Moreover, in view of the phenotypic and genetic diversity of some SCV pairs, particular attention should be paid to the investigation of all types of observed colony morphologies, and isolates should be subjected to antimicrobial susceptibility testing.

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Phenotypic and Genotypic Characteristics of Small Colony Variants and Their Role in Chronic Infection

Microbiology Insights ◽

10.4137/mbi.s25800 ◽

2015 ◽

Vol 8 ◽

pp. MBI.S25800 ◽

Cited By ~ 38

Author(s):

Benjamin E. Johns ◽

Kevin J. Purdy ◽

Nicholas P. Tucker ◽

Sarah E. Maddocks

Keyword(s):

Chronic Infection ◽

Antimicrobial Treatment ◽

Microbial Populations ◽

Phenotypic Characteristics ◽

Genetic Changes ◽

Small Colony Variant ◽

Small Colony ◽

A Minor ◽

Genotypic Characteristics ◽

Slow Growing

Small colony variant (SCV) bacteria arise spontaneously within apparently homogeneous microbial populations, largely in response to environmental stresses, such as antimicrobial treatment. They display unique phenotypic characteristics conferred in part by heritable genetic changes. Characteristically slow growing, SCVs comprise a minor proportion of the population from which they arise but persist by virtue of their inherent resilience and host adaptability. Consequently, SCVs are problematic in chronic infection, where antimicrobial treatment is administered during the acute phase of infection but fails to eradicate SCVs, which remain within the host causing recurrent or chronic infection. This review discusses some of the phenotypic and genotypic changes that enable SCVs to successfully proliferate within the host environment as potential pathogens and strategies that could ameliorate the resolution of infection where SCVs are present.

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Chronic Prosthetic Hip Infection Caused by a Small-Colony Variant of Escherichia coli

Journal of Clinical Microbiology ◽

10.1128/jcm.36.9.2530-2534.1998 ◽

1998 ◽

Vol 36 (9) ◽

pp. 2530-2534 ◽

Cited By ~ 45

Author(s):

Andreas Roggenkamp ◽

Andreas Sing ◽

Mathias Hornef ◽

Ulrich Brunner ◽

Ingo B. Autenrieth ◽

...

Keyword(s):

Escherichia Coli ◽

Biochemical Characterization ◽

Growth Stimulation ◽

Small Colony Variant ◽

E Coli ◽

Feeding Experiments ◽

Hip Infection ◽

Gentamicin Resistance ◽

Small Colony ◽

Slow Growing

From two different specimens of a chronic prosthetic hip infection taken at an interval of 2 months a slow-growing gram-negative bacterium was isolated in pure culture. The strain grew with the typical features of a small-colony variant (SCV). 16S rRNA sequencing identified the bacterium as Escherichia coli. Biochemical characterization demonstrated multiple phenotypic alterations of a mutant carrying a defect in the heme biosynthetic pathway (Hem−): (i) catalase and nitrate reductase reactions were both negative, (ii) a negative benzidine reaction demonstrated the lack of heme-containing cytochromes, and (iii) growth stimulation under anaerobic conditions as well as gentamicin resistance indicated defective aerobic respiration. PCR and Southern hybridization demonstrated that the mutation of the SCV of E. coli was localized in the hemB gene and was most likely due to a deletion of the hemB gene. On blood agar plates revertants were recognized growing as normal-sized colonies between the dominant small colonies of the strain. Feeding experiments indicated that the revertants but not the small colonies were permeable for hemin. A strong antibody response against the infecting SCV of E. coli was found. To our knowledge, this is the first report of a Hem− E. coli strain as the etiological agent of a chronic bacterial infection.

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Influence of the Protein Kinase C Activator Phorbol Myristate Acetate on the Intracellular Activity of Antibiotics against Hemin- and Menadione-Auxotrophic Small-Colony Variant Mutants of Staphylococcus aureus and Their Wild-Type Parental Strain in Human THP-1 Cells

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.01031-12 ◽

2012 ◽

Vol 56 (12) ◽

pp. 6166-6174 ◽

Cited By ~ 11

Author(s):

Laetitia G. Garcia ◽

Sandrine Lemaire ◽

Barbara C. Kahl ◽

Karsten Becker ◽

Richard A. Proctor ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Parental Strain ◽

Wild Type ◽

Content Type ◽

Small Colony Variant ◽

Intracellular Activity ◽

Kinase C ◽

Pharmacodynamic Profile ◽

Small Colony ◽

Intracellular Fate

ABSTRACTIn a previous study (L. G. Garcia et al., Antimicrob. Agents Chemother. 56:3700–3711, 2012), we evaluated the intracellular fate ofmenDandhemBmutants (corresponding to menadione- and hemin-dependent small-colony variants, respectively) of the parental COL methicillin-resistantStaphylococcus aureusstrain and the pharmacodynamic profile of the intracellular activity of a series of antibiotics in human THP-1 monocytes. We have now examined the phagocytosis and intracellular persistence of the same strains in THP-1 cells activated by phorbol 12-myristate 13-acetate (PMA) and measured the intracellular activity of gentamicin, moxifloxacin, and oritavancin in these cells. Postphagocytosis intracellular counts and intracellular survival were lower in PMA-activated cells, probably due to their higher killing capacities. Gentamicin and moxifloxacin showed a 5- to 7-fold higher potency (lower static concentrations) against the parental strain, itshemBmutant, and the genetically complemented strain in PMA-activated cells and against themenDstrain in both activated and nonactivated cells. This effect was inhibited when cells were incubated withN-acetylcysteine (a scavenger of oxidant species). In parallel, we observed that the MICs of these drugs were markedly reduced if bacteria had been preexposed to H2O2. In contrast, the intracellular potency of oritavancin was not different in activated and nonactivated cells and was not decreased by the addition ofN-acetylcysteine, regardless of the phenotype of the strains. The oritavancin MIC was also unaffected by preincubation of the bacteria with H2O2. Thus, activation of THP-1 cells by PMA may increase the intracellular potency of certain antibiotics (probably due to synergy with reactive oxygen species), but this effect cannot be generalized to all antibiotics.

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Catheter Colonization and Abscess Formation Due to Staphylococcus epidermidis with Normal and Small-Colony-Variant Phenotype Is Mouse Strain Dependent

PLoS ONE ◽

10.1371/journal.pone.0036602 ◽

2012 ◽

Vol 7 (5) ◽

pp. e36602 ◽

Cited By ~ 8

Author(s):

Gunnar Sander ◽

Tina Börner ◽

André Kriegeskorte ◽

Christof von Eiff ◽

Karsten Becker ◽

...

Keyword(s):

Mouse Strain ◽

Staphylococcus Epidermidis ◽

Abscess Formation ◽

Catheter Colonization ◽

Small Colony Variant ◽

Variant Phenotype ◽

Small Colony ◽

Strain Dependent

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Activities of Daptomycin and Comparative Antimicrobials, Singly and in Combination, against Extracellular and Intracellular Staphylococcus aureus and Its Stable Small-Colony Variant in Human Monocyte-Derived Macrophages and in Broth

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.01480-07 ◽

2008 ◽

Vol 52 (5) ◽

pp. 1829-1833 ◽

Cited By ~ 22

Author(s):

Aldona L. Baltch ◽

William J. Ritz ◽

Lawrence H. Bopp ◽

Phyllis Michelsen ◽

Raymond P. Smith

Keyword(s):

Staphylococcus Aureus ◽

Drug Combination ◽

Human Monocyte ◽

Drug Combinations ◽

Small Colony Variants ◽

Small Colony Variant ◽

Small Colony

ABSTRACT We investigated the antistaphylococcal activities of daptomycin, gentamicin, and rifampin against two Staphylococcus aureus strains and their stable small-colony variants, singly and in combination, in human monocyte-derived macrophages and in broth. Intracellularly, the three-drug combination and two-drug combinations with rifampin were most effective. Extracellularly, daptomycin, daptomycin plus gentamicin, gentamicin plus rifampin, and the three-drug combination had similar activities.

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