Antimicrobial, Antibiofilm, and Anti-persister Activities of Penfluridol Against Staphylococcus aureus

Staphylococcus aureus has increasingly attracted global attention as a major opportunistic human pathogen owing to the emergence of biofilms (BFs) and persisters that are known to increase its antibiotic resistance. However, there are still no effective antimicrobial agents in clinical settings. This study investigated the antimicrobial activity of penfluridol (PF), a long-acting antipsychotic drug, against S. aureus and its clinical isolates via drug repurposing. PF exhibited strong bactericidal activity against S. aureus, with a minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of 4–8 and 16–32 μg/ml, respectively. PF could significantly inhibit biofilm formation and eradicate 24 h preformed biofilms of S. aureus in a dose-dependent manner. Furthermore, PF could effectively kill methicillin-resistant S. aureus (MRSA) persister cells and demonstrated considerable efficacy in a mouse model of subcutaneous abscess, skin wound infection, and acute peritonitis caused by MRSA. Notably, PF exerted almost no hemolysis activity on human erythrocytes, with limited cytotoxicity and low tendency to cause resistance. Additionally, PF induced bacterial membrane permeability and ATP release and further caused membrane disruption, which may be the underlying antibacterial mechanism of PF. In summary, our findings suggest that PF has the potential to serve as a novel antimicrobial agent against S. aureus biofilm- or persister-related infections.

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Alpha-Toxin Is Required for Biofilm Formation by Staphylococcus aureus

Journal of Bacteriology ◽

10.1128/jb.185.10.3214-3217.2003 ◽

2003 ◽

Vol 185 (10) ◽

pp. 3214-3217 ◽

Cited By ~ 127

Author(s):

Nicky C. Caiazza ◽

G. A. O'Toole

Keyword(s):

Staphylococcus Aureus ◽

Biofilm Formation ◽

Antimicrobial Agents ◽

Clinical Settings ◽

Alpha Toxin ◽

Flow Conditions ◽

Alpha Hemolysin ◽

Integral Role ◽

Hemolytic Toxin ◽

Plastic Surfaces

ABSTRACT Staphylococcus aureus is a common pathogen associated with nosocomial infections. It can persist in clinical settings and gain increased resistance to antimicrobial agents through biofilm formation. We have found that alpha-toxin, a secreted, multimeric, hemolytic toxin encoded by the hla gene, plays an integral role in biofilm formation. The hla mutant was unable to fully colonize plastic surfaces under both static and flow conditions. Based on microscopy studies, we propose that alpha-hemolysin is required for cell-to-cell interactions during biofilm formation.

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Differential effects of antibiotics on neutrophils exposed to lipoteichoic acid derived from Staphylococcus aureus

Annals of Clinical Microbiology and Antimicrobials ◽

10.1186/s12941-020-00392-w ◽

2020 ◽

Vol 19 (1) ◽

Author(s):

Marquerita Algorri ◽

Annie Wong-Beringer

Keyword(s):

Staphylococcus Aureus ◽

Antimicrobial Agents ◽

Lipoteichoic Acid ◽

Neutrophil Function ◽

Exposure Level ◽

Dependent Manner ◽

Concentration Dependent Manner ◽

Persistent Bacteremia ◽

Neutrophil Survival

Abstract Background Persistent bacteremia occurs in at least 30% of patients with Staphylococcus aureus bloodstream infection (SAB) and may be attributable to a dysregulated host immune response. Neutrophils interact with a variety of S. aureus microbial factors, including lipoteichoic acid (LTA), to activate phagocytic function in a concentration-dependent manner. Antibiotics have been shown to exert both direct antimicrobial action as well as immunomodulatory effects. In this study, we compared the effects of different anti-staphylococcal antibiotics on LTA-mediated immune activation of neutrophils. Methods Neutrophils obtained from healthy volunteers were exposed to two levels of LTA (1 and 10 μg/ml) with or without addition of antibiotics from different pharmacologic classes (vancomycin, daptomycin, ceftaroline). Neutrophil function was assessed by examining phagocytic response, activation (CD11b, CD62L expression), Toll-like receptor-2 expression, cell survival and apoptosis, and CXCL8 release. Results Differential LTA-mediated antibiotic effects on neutrophil function were observed primarily at the high LTA exposure level. Ceftaroline in the presence of 10 μg/ml LTA had the most prominent effects on phagocytosis and CD11b and CD62L expression, with trends towards increased neutrophil survival and preservation of CXCL8 release when compared to daptomycin and vancomycin with the latter significantly dampening PMN CXCL8 release. Conclusions Select antimicrobial agents, such as ceftaroline, exert immunostimulatory effects on neutrophils exposed to S. aureus LTA, which when confirmed in vivo, could be leveraged for its dual immunomodulatory and antibacterial actions for the treatment of persistent SAB mediated by a dysregulated host response.

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Variation in Biofilm-Forming Potential of Staphylococcus aureus from Clinical and Non-Clinical Sources

Journal of Advances in Microbiology ◽

10.9734/jamb/2021/v21i130314 ◽

2021 ◽

pp. 1-7

Author(s):

K. Otokunefor ◽

J. J. Jesutobi ◽

O. E. Agbagwa

Keyword(s):

Staphylococcus Aureus ◽

Antimicrobial Agents ◽

Clinical Isolates ◽

Clinical Settings ◽

High Association ◽

Term Survival ◽

Medical Microbiology ◽

Potential Marker ◽

Port Harcourt

Introduction: Biofilm forming ability has been described as a potential marker of pathogenicity, particularly in Staphylococcus aureus. These biofilms are notable as an important contributor to virulence abilities, further aiding the producing strain in long term survival and resistance to antimicrobial agents. Regional data exploring biofilm forming ability of S. aureus from various sources is limited. This study therefore set out to explore variations in biofilm-forming potential of S. aureus from clinical and non-clinical sources. Place and Duration of Study: Medical Microbiology Laboratory, Department of Microbiology, University of Port Harcourt, Nigeria from August to October 2019. Methodology: Eighty five S. aureus clinical and non-clinical isolates were studied. Biofilm-forming potential was assessed using the Congo Red agar (CRA) method which describes both the presence and degree biofilm-forming potential. Results: Majority of isolates (65.9%) did not exhibit any biofilm-forming potential using the CRA method. Biofilm-forming potential however appeared source based with 100% of non-clinical S. aureus isolates lacking biofilm-forming potential, while 58% of clinical isolates showed biofilm-forming potential. A higher proportion (65.5%) of the clinical isolates exhibiting biofilm-forming potential where associated with strong biofilm-forming potential. Conclusion: This study reports a high association of biofilm-forming potential with S. aureus isolated from clinical rather than non-clinical settings. If this characteristic can indeed be used as a general marker of pathogenicity would however require more extensive studies.

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Determination of Antimicrobial Potentials of Ethanol Extract of Combretum dolichopentalum Leaves by Total Dehydrogenase Activity Assay

International Journal of Pharmacology Phytochemistry and Ethnomedicine ◽

10.18052/www.scipress.com/ijppe.8.27 ◽

2017 ◽

Vol 8 ◽

pp. 27-40

Author(s):

Favour Ntite Ujowundu

Keyword(s):

Escherichia Coli ◽

Staphylococcus Aureus ◽

Dehydrogenase Activity ◽

Antimicrobial Agents ◽

Ethanol Extract ◽

Bactericidal Effect ◽

Salmonella Typhi ◽

Vaginal Swab ◽

Dependent Manner ◽

Streptococcus Pneumonia

The viability of microorganisms can be determined by the total dehydrogenase activity (DHA). Thus, a reduction in total dehydrogenase activity is an indication of the bactericidal effect of plant extract. The antimicrobial potentials of ethanol extract of Combretum dolichopentalum (EECD) leaves on microbial isolates from stool, degenerated wound, and high vaginal swab were determined by the total dehydrogenase activity. The microbial cells were standardized in a spectrophotometer to an optical density of 0.70 at 420 nm and used as standardized cell suspension (inoculum) in the dehydrogenase assay. The results obtained indicated that EECD leaves were effective antimicrobial agents against Escherichia coli, Staphylococcus aureus, Salmonella typhi and Streptococcus pneumonia isolates. Threshold inhibitory concentrations of the extracts showed that EECD leaves inhibited dehydrogenase activity in all the organisms in a dose dependent manner. At 355.78 μg/ml, EECD leaves achieved an IC50against E. coli, and at 349.42 µg/ml and 843.80 µg/ml EECD obtained an IC50against Streptococcus pneumonia and Staphylococcus aureus respectively. Also, at 2270.68 μg/ml EECD leaves eliminated 100 % S. typhi to achieve 100 % inhibiting concentration. C. dolichopentalum makes a promising drug with bactericidal effect especially against Escherichia coli and Salmonella typhi.

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Post-antibiotic and post-antibiotic sub-MIC effects of gentamicin, sophoraflavanone G, and their combination against a clinical isolate of Staphylococcus aureus

Asian Biomedicine ◽

10.2478/abm-2010-0108 ◽

2010 ◽

Vol 4 (5) ◽

pp. 821-826 ◽

Cited By ~ 1

Author(s):

Ruhollah Mirjani ◽

Fatemeh Rafii ◽

Mohammad Sharifzadeh ◽

Massoud Amanlou ◽

Ahmad R. Shahverdi

Keyword(s):

Staphylococcus Aureus ◽

Antimicrobial Agents ◽

Fold Increase ◽

Dependent Manner ◽

Combination Methods ◽

Antibiotic Effect ◽

Short Term Exposure ◽

Drug Determination ◽

Dosing Intervals

Abstract Background: Post-antibiotic effect (PAE) defines the potential of a drug to delay re-growth of a bacterial population after short-term exposure and removal of a drug. Determination of the PAE is recommended in preclinical evaluation of all new antimicrobial agents, because it influences optimal antimicrobial dosing intervals. Objective: Evaluate the PAE and PA-SME of gentamicin and sophoraflavanone G against Staphylococcus aureus (S. aureus) itself and in combination. Methods: A spectrophotometric method was used to determine the PAE and PA-SME. Results: Sophoraflavanone G and gentamicin, showed considerable PAE and PA-SME at the tested concentrations against S. aureus. The increased duration of PAE caused by sophoraflavanone G and gentamicin was dosedependent. In addition, sophoraflavanone G at sub-MIC concentrations enhanced the PAE and PA-SME of gentamicin in a dose-dependent manner. The highest enhancing effect was observed for gentamicin at the synergistic MIC and 1/2 the synergistic MIC levels against S. aureus 0.03 μg/mL (30 ng/mL) of sophoraflavanone G (with PAE=55 minutes). It enhanced the post-antibiotic sub-MIC effect (PA-SME) duration of gentamicin at concentrations of 4 μg/mL from 15 minutes to 80 minutes (a six-fold increase). Conclusion: Sophoraflavanone G is promising for the preparation of an effective therapeutic formulation against gentamicin-resistant S. aureus.

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Identification and Characterization of SirA, an Iron-Regulated Protein from Staphylococcus aureus

Journal of Bacteriology ◽

10.1128/jb.181.5.1436-1443.1999 ◽

1999 ◽

Vol 181 (5) ◽

pp. 1436-1443 ◽

Cited By ~ 44

Author(s):

Jon H. Heinrichs ◽

LaVette E. Gatlin ◽

Charles Kunsch ◽

Gil H. Choi ◽

Mark S. Hanson

Keyword(s):

Staphylococcus Aureus ◽

Pathogenic Bacteria ◽

Antimicrobial Agents ◽

Genomic Sequence ◽

Iron Acquisition ◽

Bacterial Species ◽

Dependent Manner ◽

Dyad Symmetry ◽

Siderophore Transport

ABSTRACT The acquisition of iron by pathogenic bacteria is often a crucial step in establishing infection. To accomplish this, many bacteria, including Staphylococcus aureus, produce low-molecular-weight iron-chelating siderophores. However, the secretion and transport of these molecules in gram-positive organisms are poorly understood. The sequence, organization, and regulation of genes involved in siderophore transport are conserved among gram-negative bacteria. We used this information to identify a putative siderophore transport locus from an S. aureus genomic sequence database. This locus contains three predicted open reading frames with a high degree of homology to genes involved in siderophore uptake in several bacterial species, in particular the cbrlocus of the plant pathogen Erwinia chrysanthemi. The first gene in the locus, which we have designated sir for staphylococcal iron regulated, encodes a putative lipoprotein with a molecular mass of 37 kDa. The open reading frame is preceded by a 19-bp region of dyad symmetry with homology for operator sequences controlling iron-regulated expression of genes in other bacteria. Fur titration experiments indicate that this region of dyad symmetry is sufficient for Fur-dependent regulation in Escherichia coli. The expression of this gene was repressed, in a dose-dependent manner, by the addition of iron to the S. aureus culture medium. sir-encoded proteins may be involved in iron acquisition in vivo and therefore may be targets for antimicrobial agents.

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Chlorobutanol, a Preservative of Desmopressin, Inhibits Human Platelet Aggregation and Release In Vitro

Thrombosis and Haemostasis ◽

10.1055/s-0038-1647339 ◽

1990 ◽

Vol 64 (03) ◽

pp. 473-477 ◽

Cited By ~ 4

Author(s):

Shih-Luen Chen ◽

Wu-Chang Yang ◽

Tung-Po Huang ◽

Shiang Wann ◽

Che-ming Teng

Keyword(s):

Arachidonic Acid ◽

Platelet Aggregation ◽

Atp Release ◽

Free Calcium ◽

Dependent Manner ◽

Antiplatelet Effect ◽

Human Platelet Aggregation ◽

Acid Pathway ◽

Arachidonic Acid Pathway

SummaryTherapeutic preparations of desmopressin for parenteral use contain the preservative chlorobutanol (5 mg/ml). We show here that chlorobutanol is a potent inhibitor of platelet aggregation and release. It exhibited a significant inhibitory activity toward several aggregation inducers in a concentration- and time-dependent manner. Thromboxane B2 formation, ATP release, and elevation of cytosolic free calcium caused by collagen, ADP, epinephrine, arachidonic acid and thrombin respectively were markedly inhibited by chlorobutanol. Chlorobutanol had no effect on elastase- treated platelets and its antiplatelet effect could be reversed. It is concluded that the antiplatelet effect of chlorobutanol is mainly due to its inhibition on the arachidonic acid pathway but it is unlikely to have a nonspecitic toxic effect. This antiplatelet effect of chlorobutanol suggests that desmopressin, when administered for improving hemostasis, should not contain chlorobutanol as a preservative.

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Trimucytin: A Collagen-Like Aggregating Inducer Isolated from Trimeresurus mucrosquamatus Snake Venom

Thrombosis and Haemostasis ◽

10.1055/s-0038-1651597 ◽

1993 ◽

Vol 69 (03) ◽

pp. 286-292 ◽

Cited By ~ 13

Author(s):

Che-Ming Teng ◽

Feng-Nien Ko ◽

Inn-Ho Tsai ◽

Man-Ling Hung ◽

Tur-Fu Huang

Keyword(s):

Platelet Aggregation ◽

Snake Venom ◽

Inositol Phosphate ◽

Shape Change ◽

Platelet Activating Factor ◽

Atp Release ◽

Platelet Membrane ◽

Thromboxane B2 ◽

Dependent Manner ◽

Concentration Dependent Manner

SummaryTrimucytin is a potent platelet aggregation inducer isolated from Trimeresurus mucrosquamatus snake venom. Similar to collagen, trimucytin has a run of (Gly-Pro-X) repeats at the N-terminal amino acids sequence. It induced platelet aggregation, ATP release and thromboxane formation in rabbit platelets in a concentration-dependent manner. The aggregation was not due to released ADP since it was not suppressed by creatine phosphate/creatine phosphokinase. It was not either due to thromboxane A2 formation because indomethacin and BW755C did not have any effect on the aggregation even thromboxane B2 formation was completely abolished by indomethacin. Platelet-activating factor (PAF) was not involved in the aggregation since a PAF antagonist, kadsurenone, did not affect. However, RGD-containing peptide triflavin inhibited the aggregation, but not the release of ATP, of platelets induced by trimucytin. Indomethacin, mepacrine, prostaglandin E1 and tetracaine inhibited the thromboxane B2 formation of platelets caused by collagen and trimucytin. Forskolin and sodium nitroprusside inhibited both platelet aggregation and ATP release, but not the shape change induced by trimucytin. In quin-2 loaded platelets, the rise of intracellular calcium concentration caused by trimucytin was decreased by 12-O-tetradecanoyl phorbol-13 acetate, imipramine, TMB-8 and indomethacin. In the absence of extracellular calcium, both collagen and trimucytin caused no thromboxane B2 formation, but still induced ATP release which was completely blocked by R 59022. Inositol phosphate formation in platelets was markedly enhanced by trimucytin and collagen. MAB1988, an antibody against platelet membrane glycoprotein Ia, inhibited trimucytinand collagen-induced platelet aggregation and ATP release. However, trimucytin did not replace the binding of 125I-labeled MAB1988 to platelets. Platelets pre-exposed to trimucytin were resistant to the second challenge with trimucytin itself or collagen. It is concluded that trimucytin may activate collagen receptors on platelet membrane, and cause aggregation and release mainly through phospholipase C-phosphoinositide pathway.

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