A Novel δ-Hemolysis Screening Method for Detecting Heteroresistant Vancomycin-Intermediate Staphylococcus aureus and Vancomycin-Intermediate S. aureus

Cafiso, Viviana; Bertuccio, Taschia; Spina, Daniela; Purrello, Simona; Blandino, G; Stefani, Stefania

doi:10.1128/jcm.06307-11

Cited by 16 publications

(15 citation statements)

References 14 publications

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“…This is in agreement with other reports showing that agr -negativity is commonly selected during the course of infections [8]. Multivariate analysis also revealed that glycopeptide resistance was significantly associated with agr dysfunction ( p = 0.02; CI 95%: 1.20–12.76) (Table 3), in accordance with previous studies [14]–[16]. Interestingly, methicillin resistance, which was associated with agr dysfunction in the univariate analysis (Table 2), appeared to be a confounding factor in the logistic regression model (Table 3).…”

Section: Discussionsupporting

confidence: 92%

Detection of Staphylococcus aureus Delta-Toxin Production by Whole-Cell MALDI-TOF Mass Spectrometry

et al. 2012

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The aim of the present study was to detect the Staphylococcus aureus delta-toxin using Whole-Cell (WC) Matrix Assisted Laser Desorption Ionization - Time-of-Flight (MALDI-TOF) mass spectrometry (MS), correlate delta-toxin expression with accessory gene regulator ( agr ) status, and assess the prevalence of agr deficiency in clinical isolates with and without resistance to methicillin and glycopeptides. The position of the delta-toxin peak in the mass spectrum was identified using purified delta-toxin and isogenic wild type and mutant strains for agr-rna III, which encodes delta-toxin. Correlation between delta-toxin production and agr RNAIII expression was assessed by northern blotting. A series of 168 consecutive clinical isolates and 23 unrelated glycopeptide-intermediate S. aureus strains (GISA/heterogeneous GISA) were then tested by WC-MALDI-TOF MS. The delta-toxin peak was detected at 3005±5 Thomson, as expected for the naturally formylated delta toxin, or at 3035±5 Thomson for its G10S variant. Multivariate analysis showed that chronicity of S. aureus infection and glycopeptide resistance were significantly associated with delta-toxin deficiency ( p = 0.048; CI 95%: 1.01–10.24; p = 0.023; CI 95%: 1.20–12.76, respectively). In conclusion, the S. aureus delta-toxin was identified in the WC-MALDI-TOF MS spectrum generated during routine identification procedures. Consequently, agr status can potentially predict infectious complications and rationalise application of novel virulence factor-based therapies.

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Section: Discussionsupporting

confidence: 92%

Detection of Staphylococcus aureus Delta-Toxin Production by Whole-Cell MALDI-TOF Mass Spectrometry

et al. 2012

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“…The latter is a reference strain which produces only β-hemolysin on sheep blood agar plates. A zone of enhanced hemolysis is seen at the junctions where β & δ lysis zones overlap [110]. Original results of a representative experiment demonstrating various hemolysin activities on blood agar plates are presented from our laboratory (Figure 8).…”

Section: Qualitative Methodsmentioning

confidence: 99%

“…Quantitative real time reverse transcription PCR (qRTPCR) is used to measure the transcripts of hla & hld in S. aureus isolates and gyrB is used as a normalizer for hld [110], in case of alpha hemolysin 16S rRNA gene was used as internal or reference control [112].…”

Section: Real Time Pcrmentioning

confidence: 99%

Hemolysins of <i>Staphylococcus aureus</i>—An Update on Their Biology, Role in Pathogenesis and as Targets for Anti-Virulence Therapy

Divyakolu¹,

Chikkala²,

Ks³

et al. 2019

AID

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Staphylococcus aureus is a dangerous gram positive bacterial pathogen which, not only evades the host's immune system but also can destroy the leucocytes especially neutrophils. It has an embodiment of virulence factors most of which are secreted. Staphylococcus aureus secretes a number of toxins which cause tissue damage and facilitate spreading and nutrients uptake. Among the toxins, hemolysins α, β, γ, δ and Panton Valentine Leukocidin (PVL) are unique that they drill pores in the membrane, leading to the efflux of vital molecules and metabolites. Hemolysins also help in the scavenging of iron, although many of them also have leucolytic properties. α-hemolysin, also known as α-toxin, is the most prominent cytotoxin which damages a wide range of host cells including epithelial cells, endothelial cells, erythrocytes, monocytes, keratinocytes and it damages cell membrane and induces apoptosis. β-Hemolysin significantly affects human immune cell function. It has Mg 2+ dependent sphingomyelinase activity and degrades sphingomyelin of plasma membrane into phosphorylcholine and ceramides. The bi-component leukocidins, which include γ-hemolysin and PVL, attack human phagocytic

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“…MBIC and MBEC experiments were performed using a modified version of the Calgary biofilm device method (Ceri et al, 1999;Cafiso et al, 2010). In brief, 20 ml 10 8 c.f.u.…”

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confidence: 99%

Inhibition of biofilm maturation by linezolid in meticillin-resistant Staphylococcus epidermidis clinical isolates: comparison with other drugs

Reiter

Villa

Paim

et al. 2013

Journal of Medical Microbiology

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Biofilm resistance mechanisms are multifactorial and vary from one organism to another. The purpose of this study was to investigate the efficacy of linezolid against indwelling device-related meticillin-resistant Staphylococcus epidermidis (MRSE) biofilm, and compare this with other antimicrobials. MICs, minimum biofilm inhibitory concentrations (MBICs) and minimum biofilm eradication concentrations (MBECs) were determined by the microtitre plate method. Fourteen and thirteen isolates from patients with indwelling device-related bacteraemia (IDB) and indwelling device colonization not associated with bacteraemia, respectively, were assessed. High MBIC was associated with a high intensity of biofilm formation (gentamicin r50.796; linezolid r50.477; rifampicin r50.634; tigecycline r50.410; and vancomycin r50.771), but this correlation was not observed with MBEC. Linezolid demonstrated better in vitro antimicrobial activity than other antimicrobials (MBIC -gentamicin P,0.001, rifampicin P50.019, vancomycin P50.008; MBEC -gentamicin P,0.001, rifampicin P50.002, vancomycin P,0.001). Biofilm growth inhibition was strongly associated with biofilm formation intensity; however, biofilm eradication was not cell number dependent. MRSE biofilm eradication would represent a huge advance for IDB, although high concentrations of gentamicin, linezolid, rifampicin, tigecycline and vancomycin were required for that. In general, linezolid reached better in vitro concentrations and was demonstrated to be highly active against MRSE biofilms by inhibiting their growth during biofilm formation.

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A Novel δ-Hemolysis Screening Method for Detecting Heteroresistant Vancomycin-Intermediate Staphylococcus aureus and Vancomycin-Intermediate S. aureus

Abstract: We assessed a new screening method, based on ␦-hemolysin production in the presence of 6 mg/liter vancomycin, to distinguish heteroresistant vancomycin-intermediate Staphylococcus aureus (

Cited by 16 publications

References 14 publications

Detection of Staphylococcus aureus Delta-Toxin Production by Whole-Cell MALDI-TOF Mass Spectrometry

Detection of Staphylococcus aureus Delta-Toxin Production by Whole-Cell MALDI-TOF Mass Spectrometry

Hemolysins of <i>Staphylococcus aureus</i>—An Update on Their Biology, Role in Pathogenesis and as Targets for Anti-Virulence Therapy

Inhibition of biofilm maturation by linezolid in meticillin-resistant Staphylococcus epidermidis clinical isolates: comparison with other drugs

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A Novel δ-Hemolysis Screening Method for Detecting Heteroresistant Vancomycin-Intermediate Staphylococcus aureus and Vancomycin-Intermediate S. aureus

Abstract: We assessed a new screening method, based on ␦-hemolysin production in the presence of 6 mg/liter vancomycin, to distinguish heteroresistant vancomycin-intermediate Staphylococcus aureus (

Cited by 16 publications

References 14 publications

Detection of Staphylococcus aureus Delta-Toxin Production by Whole-Cell MALDI-TOF Mass Spectrometry

Detection of Staphylococcus aureus Delta-Toxin Production by Whole-Cell MALDI-TOF Mass Spectrometry

Hemolysins of &lt;i&gt;Staphylococcus aureus&lt;/i&gt;—An Update on Their Biology, Role in Pathogenesis and as Targets for Anti-Virulence Therapy

Inhibition of biofilm maturation by linezolid in meticillin-resistant Staphylococcus epidermidis clinical isolates: comparison with other drugs

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Hemolysins of <i>Staphylococcus aureus</i>—An Update on Their Biology, Role in Pathogenesis and as Targets for Anti-Virulence Therapy