The Tape Measure Protein of the Staphylococcus aureus Bacteriophage vB_SauS-phiIPLA35 Has an Active Muramidase Domain

ABSTRACTTailed double-stranded DNA (dsDNA) bacteriophages frequently harbor structural proteins displaying peptidoglycan hydrolytic activities. The tape measure protein fromStaphylococcus aureusbacteriophage vB_SauS-phiIPLA35 has a lysozyme-like and a peptidase_M23 domain. This report shows that the lysozyme-like domain (TG1) has muramidase activity and exhibitsin vitrolytic activity against liveS. aureuscells, an activity that could eventually find use in the treatment of infections.

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Novel Bacteriophage Lysin with Broad Lytic Activity Protects against Mixed Infection by Streptococcus pyogenes and Methicillin-Resistant Staphylococcus aureus

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.02526-12 ◽

2013 ◽

Vol 57 (6) ◽

pp. 2743-2750 ◽

Cited By ~ 99

Author(s):

Daniel B. Gilmer ◽

Jonathan E. Schmitz ◽

Chad W. Euler ◽

Vincent A. Fischetti

Keyword(s):

Staphylococcus Aureus ◽

Streptococcus Pyogenes ◽

Catalytic Domain ◽

Group A Streptococcus ◽

Group B Streptococcus ◽

Streptococcus Suis ◽

Lytic Activity ◽

Methicillin Resistant ◽

Content Type

ABSTRACTMethicillin-resistantStaphylococcus aureus(MRSA) andStreptococcus pyogenes(group A streptococcus [GrAS]) cause serious and sometimes fatal human diseases. They are among the many Gram-positive pathogens for which resistance to leading antibiotics has emerged. As a result, alternative therapies need to be developed to combat these pathogens. We have identified a novel bacteriophage lysin (PlySs2), derived from aStreptococcus suisphage, with broad lytic activity against MRSA, vancomycin-intermediateS. aureus(VISA),Streptococcus suis,Listeria,Staphylococcus simulans,Staphylococcus epidermidis,Streptococcus equi,Streptococcus agalactiae(group B streptococcus [GBS]),S. pyogenes,Streptococcus sanguinis, group G streptococci (GGS), group E streptococci (GES), andStreptococcus pneumoniae. PlySs2 has an N-terminal cysteine-histidine aminopeptidase (CHAP) catalytic domain and a C-terminal SH3b binding domain. It is stable at 50°C for 30 min, 37°C for >24 h, 4°C for 15 days, and −80°C for >7 months; it maintained full activity after 10 freeze-thaw cycles. PlySs2 at 128 μg/mlin vitroreduced MRSA andS. pyogenesgrowth by 5 logs and 3 logs within 1 h, respectively, and exhibited a MIC of 16 μg/ml for MRSA. A single, 2-mg dose of PlySs2 protected 92% (22/24) of the mice in a bacteremia model of mixed MRSA andS. pyogenesinfection. Serially increasing exposure of MRSA andS. pyogenesto PlySs2 or mupirocin resulted in no observed resistance to PlySs2 and resistance to mupirocin. To date, no other lysin has shown such notable broad lytic activity, stability, and efficacy against multiple, leading, human bacterial pathogens; as such, PlySs2 has all the characteristics to be an effective therapeutic.

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Alanine Scanning Mutagenesis of the MEDI4893 (Suvratoxumab) Epitope Reduces Alpha Toxin Lytic Activity In Vitro and Staphylococcus aureus Fitness in Infection Models

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.01033-18 ◽

2018 ◽

Vol 62 (11) ◽

Cited By ~ 4

Author(s):

C. Tkaczyk ◽

E. Semenova ◽

Y. Y. Shi ◽

K. Rosenthal ◽

V. Oganesyan ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Pore Formation ◽

Severe Disease ◽

Treatment Strategies ◽

Lytic Activity ◽

Alpha Toxin ◽

Alanine Scanning Mutagenesis ◽

Content Type

ABSTRACT Alpha toxin (AT) is a cytolytic pore-forming toxin that plays a key role in Staphylococcus aureus pathogenesis; consequently, extensive research was undertaken to understand the AT mechanism of action and its utility as a target for novel prophylaxis and treatment strategies against S. aureus infections. MEDI4893 (suvratoxumab) is a human anti-AT IgG1 monoclonal antibody (MAb) that targets AT and is currently in phase 2 clinical development. As shown previously, the MEDI4893-binding epitope on AT is comprised of the highly conserved amino acid regions 177 to 200 and 261 to 271, suggesting these amino acids are important for AT function. To test this hypothesis and gain insight into the effect of mutations in the epitope on AT neutralization by MEDI4893, nine MEDI4893 contact residues in AT were individually mutated to alanine. Consistent with our hypothesis, 8 out of 9 mutants exhibited >2-fold loss in lytic activity resulting from a defect in cell binding and pore formation. MEDI4893 binding affinity was reduced >2-fold (2- to 27-fold) for 7 out of 9 mutants, and no binding was detected for the W187A mutant. MEDI4893 effectively neutralized all of the lytic mutants in vitro and in vivo. When the defective mutants were introduced into an S. aureus clinical isolate, the mutant-expressing strains exhibited less severe disease in mouse models and were effectively neutralized by MEDI4893. These results indicate the MEDI4893 epitope is highly conserved due in part to its role in AT pore formation and bacterial fitness, thereby decreasing the likelihood for the emergence of MAb-resistant variants.

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Enhanced Staphylolytic Activity of the Staphylococcus aureus Bacteriophage vB_SauS-phiIPLA88 HydH5 Virion-Associated Peptidoglycan Hydrolase: Fusions, Deletions, and Synergy with LysH5

Applied and Environmental Microbiology ◽

10.1128/aem.07621-11 ◽

2012 ◽

Vol 78 (7) ◽

pp. 2241-2248 ◽

Cited By ~ 45

Author(s):

Lorena Rodríguez-Rubio ◽

Beatriz Martínez ◽

Ana Rodríguez ◽

David M. Donovan ◽

Pilar García

Keyword(s):

Staphylococcus Aureus ◽

Fusion Proteins ◽

Antimicrobial Agents ◽

Lytic Activity ◽

Peptidoglycan Hydrolase ◽

Content Type ◽

Gram Positive Bacteria ◽

Peptidoglycan Hydrolases ◽

Antimicrobial Synergy

ABSTRACTVirion-associated peptidoglycan hydrolases have potential as antimicrobial agents due to their ability to lyse Gram-positive bacteria on contact. In this work, our aim was to improve the lytic activity of HydH5, a virion-associated peptidoglycan hydrolase from theStaphylococcus aureusbacteriophage vB_SauS-phiIPLA88. Full-length HydH5 and two truncated derivatives containing only the CHAP (cysteine, histidine-dependent amidohydrolase/peptidase) domain exhibited high lytic activity against liveS. aureuscells. In addition, three different fusion proteins were created between lysostaphin and HydH5, each of which showed higher staphylolytic activity than the parental enzyme or its deletion construct. Both parental and fusion proteins lysedS. aureuscells in zymograms and plate lysis and turbidity reduction assays. In plate lysis assays, HydH5 and its derivative fusions lysed bovine and humanS. aureusstrains, the methicillin-resistantS. aureus(MRSA) strain N315, and humanStaphylococcus epidermidisstrains. Several nonstaphylococcal bacteria were not affected. HydH5 and its derivative fusion proteins displayed antimicrobial synergy with the endolysin LysH5in vitro, suggesting that the two enzymes have distinct cut sites and, thus, may be more efficient in combination for the elimination of staphylococcal infections.

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Exogenous Alginate Protects Staphylococcus aureus from Killing by Pseudomonas aeruginosa

Journal of Bacteriology ◽

10.1128/jb.00559-19 ◽

2019 ◽

Vol 202 (8) ◽

Cited By ~ 2

Author(s):

Courtney E. Price ◽

Dustin G. Brown ◽

Dominique H. Limoli ◽

Vanessa V. Phelan ◽

George A. O’Toole

Keyword(s):

Staphylococcus Aureus ◽

Pseudomonas Aeruginosa ◽

Physical Space ◽

Late Time ◽

Protective Effects ◽

Content Type ◽

Alginate Production ◽

The Impact

ABSTRACT Cystic fibrosis (CF) patients chronically infected with both Pseudomonas aeruginosa and Staphylococcus aureus have worse health outcomes than patients who are monoinfected with either P. aeruginosa or S. aureus. We showed previously that mucoid strains of P. aeruginosa can coexist with S. aureus in vitro due to the transcriptional downregulation of several toxic exoproducts typically produced by P. aeruginosa, including siderophores, rhamnolipids, and HQNO (2-heptyl-4-hydroxyquinoline N-oxide). Here, we demonstrate that exogenous alginate protects S. aureus from P. aeruginosa in both planktonic and biofilm coculture models under a variety of nutritional conditions. S. aureus protection in the presence of exogenous alginate is due to the transcriptional downregulation of pvdA, a gene required for the production of the iron-scavenging siderophore pyoverdine as well as the downregulation of the PQS (Pseudomonas quinolone signal) (2-heptyl-3,4-dihydroxyquinoline) quorum sensing system. The impact of exogenous alginate is independent of endogenous alginate production. We further demonstrate that coculture of mucoid P. aeruginosa with nonmucoid P. aeruginosa strains can mitigate the killing of S. aureus by the nonmucoid strain of P. aeruginosa, indicating that the mechanism that we describe here may function in vivo in the context of mixed infections. Finally, we investigated a panel of mucoid clinical isolates that retain the ability to kill S. aureus at late time points and show that each strain has a unique expression profile, indicating that mucoid isolates can overcome the S. aureus-protective effects of mucoidy in a strain-specific manner. IMPORTANCE CF patients are chronically infected by polymicrobial communities. The two dominant bacterial pathogens that infect the lungs of CF patients are P. aeruginosa and S. aureus, with ∼30% of patients coinfected by both species. Such coinfected individuals have worse outcomes than monoinfected patients, and both species persist within the same physical space. A variety of host and environmental factors have been demonstrated to promote P. aeruginosa-S. aureus coexistence, despite evidence that P. aeruginosa kills S. aureus when these organisms are cocultured in vitro. Thus, a better understanding of P. aeruginosa-S. aureus interactions, particularly mechanisms by which these microorganisms are able to coexist in proximal physical space, will lead to better-informed treatments for chronic polymicrobial infections.

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In VitroActivities of Daptomycin-, Vancomycin-, and Teicoplanin-Loaded Polymethylmethacrylate against Methicillin-Susceptible, Methicillin-Resistant, and Vancomycin-Intermediate Strains of Staphylococcus aureus

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.05312-11 ◽

2011 ◽

Vol 55 (12) ◽

pp. 5480-5484 ◽

Cited By ~ 45

Author(s):

Yuhan Chang ◽

Wen-Chien Chen ◽

Pang-Hsin Hsieh ◽

Dave W. Chen ◽

Mel S. Lee ◽

...

Keyword(s):

Staphylococcus Aureus ◽

High Performance ◽

Low Dose ◽

Antibacterial Activities ◽

High Dose ◽

Bone Cements ◽

Antibacterial Effects ◽

Methicillin Resistant ◽

Content Type

ABSTRACTThe objective of this study was to evaluate the antibacterial effects of polymethylmethacrylate (PMMA) bone cements loaded with daptomycin, vancomycin, and teicoplanin against methicillin-susceptibleStaphylococcus aureus(MSSA), methicillin-resistantStaphylococcus aureus(MRSA), and vancomycin-intermediateStaphylococcus aureus(VISA) strains. Standardized cement specimens made from 40 g PMMA loaded with 1 g (low-dose), 4 g (middle-dose) or 8 g (high-dose) antibiotics were tested for elution characteristics and antibacterial activities. The patterns of release of antibiotics from the cement specimens were evaluated usingin vitrobroth elution assay with high-performance liquid chromatography. The activities of broth elution fluid against differentStaphylococcus aureusstrains (MSSA, MRSA, and VISA) were then determined. The antibacterial activities of all the tested antibiotics were maintained after being mixed with PMMA. The cements loaded with higher dosages of antibiotics showed longer elution periods. Regardless of the antibiotic loading dose, the teicoplanin-loaded cements showed better elution efficacy and provided longer inhibitory periods against MSSA, MRSA, and VISA than cements loaded with the same dose of vancomycin or daptomycin. Regarding the choice of antibiotics for cement loading in the treatment ofStaphylococcus aureusinfection, teicoplanin was superior in terms of antibacterial effects.

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Comparison of Borate Bioactive Glass and Calcium Sulfate as Implants for the Local Delivery of Teicoplanin in the Treatment of Methicillin-Resistant Staphylococcus aureus-Induced Osteomyelitis in a Rabbit Model

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00196-15 ◽

2015 ◽

Vol 59 (12) ◽

pp. 7571-7580 ◽

Cited By ~ 16

Author(s):

Wei-Tao Jia ◽

Qiang Fu ◽

Wen-Hai Huang ◽

Chang-Qing Zhang ◽

Mohamed N. Rahaman

Keyword(s):

Staphylococcus Aureus ◽

Bioactive Glass ◽

Calcium Sulfate ◽

Rabbit Model ◽

Local Delivery ◽

Methicillin Resistant ◽

Content Type ◽

Borate Bioactive Glass ◽

Phosphate Buffered Saline

ABSTRACTThere is growing interest in biomaterials that can cure bone infection and also regenerate bone. In this study, two groups of implants composed of 10% (wt/wt) teicoplanin (TEC)-loaded borate bioactive glass (designated TBG) or calcium sulfate (TCS) were created and evaluated for their ability to release TECin vitroand to cure methicillin-resistantStaphylococcus aureus(MRSA)-induced osteomyelitis in a rabbit model. When immersed in phosphate-buffered saline (PBS), both groups of implants provided a sustained release of TEC at a therapeutic level for up to 3 to 4 weeks while they were gradually degraded and converted to hydroxyapatite. The TBG implants showed a longer duration of TEC release and better retention of strength as a function of immersion time in PBS. Infected rabbit tibiae were treated by debridement, followed by implantation of TBG or TCS pellets or intravenous injection with TEC, or were left untreated. Evaluation at 6 weeks postimplantation showed that the animals implanted with TBG or TCS pellets had significantly lower radiological and histological scores, lower rates of MRSA-positive cultures, and lower bacterial loads than those preoperatively and those of animals treated intravenously. The level of bone regeneration was also higher in the defects treated with the TBG pellets. The results showed that local TEC delivery was more effective than intravenous administration for the treatment of MRSA-induced osteomyelitis. Borate glass has the advantages of better mechanical strength, more desirable kinetics of release of TEC, and a higher osteogenic capacity and thus could be an effective alternative to calcium sulfate for local delivery of TEC.

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Evaluation of Ceftaroline Alone and in Combination against Biofilm-Producing Methicillin-Resistant Staphylococcus aureus with Reduced Susceptibility to Daptomycin and Vancomycin in anIn VitroPharmacokinetic/Pharmacodynamic Model

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00386-15 ◽

2015 ◽

Vol 59 (8) ◽

pp. 4497-4503 ◽

Cited By ~ 23

Author(s):

Katie E. Barber ◽

Jordan R. Smith ◽

Cortney E. Ireland ◽

Blaise R. Boles ◽

Warren E. Rose ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Medical Device ◽

Bloodstream Infections ◽

Methicillin Resistant ◽

Content Type ◽

Elimination Half ◽

Antimicrobial Protection ◽

Mrsa Strains ◽

Post Hoc

ABSTRACTAnnually, medical device infections are associated with >250,000 catheter-associated bloodstream infections (CLABSI), with up to 25% mortality.Staphylococcus aureus, a primary pathogen in these infections, is capable of biofilm production, allowing organism persistence in harsh environments, offering antimicrobial protection. With increases inS. aureusisolates with reduced susceptibility to current agents, ceftaroline (CPT) offers a therapeutic alternative. Therefore, we evaluated whether CPT would have a role against biofilm-producing methicillin-resistantS. aureus(MRSA), including those with decreased susceptibilities to alternative agents. In this study, we investigated CPT activity alone or combined with daptomycin (DAP) or rifampin (RIF) against 3 clinical biofilm-producing MRSA strains in anin vitrobiofilm pharmacokinetic/pharmacodynamic (PK/PD) model. Simulated antimicrobial regimens were as follows: 600 mg of CPT every 8 h (q8h) (free maximum concentration of drug [fCmax], 17.04 mg/liter; elimination half-life [t1/2], 2.66 h), 12 mg/kg of body weight/day of DAP (fCmax, 14.7 mg/liter;t1/2, 8 h), and 450 mg of RIF q12h (fCmax, 3.5 mg/liter;t1/2, 3.4 h), CPT plus DAP, and CPT plus RIF. Samples were obtained and plated to determine colony counts. Differences in log10CFU/cm2were evaluated by analysis of variance with Tukey'spost hoctest. The strains were CPT and vancomycin susceptible and DAP nonsusceptible (DNS). CPT displayed activity throughout the experiment. DAP demonstrated initial activity with regrowth at 24 h in all strains. RIF was comparable to the drug-free control, and little benefit was observed when combined with CPT. CPT plus DAP displayed potent activity, with an average log10CFU/cm2reduction of 3.33 ± 1.01 from baseline. CPT demonstrated activity against biofilm-producing DNS MRSA. CPT plus DAP displayed therapeutic enhancement over monotherapy, providing a potential option for difficult-to-treat medical device infections.

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Bacteriocins of Non-aureus Staphylococci Isolated from Bovine Milk

Applied and Environmental Microbiology ◽

10.1128/aem.01015-17 ◽

2017 ◽

Vol 83 (17) ◽

Cited By ~ 24

Author(s):

Domonique A. Carson ◽

Herman W. Barkema ◽

Sohail Naushad ◽

Jeroen De Buck

Keyword(s):

Staphylococcus Aureus ◽

Bacterial Infections ◽

Genome Mining ◽

Bovine Milk ◽

Gene Clusters ◽

Antibiotic Use ◽

Content Type ◽

Treatment And Prevention ◽

Whole Genomes

ABSTRACT Non-aureus staphylococci (NAS), the bacteria most commonly isolated from the bovine udder, potentially protect the udder against infection by major mastitis pathogens due to bacteriocin production. In this study, we determined the inhibitory capability of 441 bovine NAS isolates (comprising 26 species) against bovine Staphylococcus aureus. Furthermore, inhibiting isolates were tested against a human methicillin-resistant S. aureus (MRSA) isolate using a cross-streaking method. We determined the presence of bacteriocin clusters in NAS whole genomes using genome mining tools, BLAST, and comparison of genomes of closely related inhibiting and noninhibiting isolates and determined the genetic organization of any identified bacteriocin biosynthetic gene clusters. Forty isolates from 9 species (S. capitis, S. chromogenes, S. epidermidis, S. pasteuri, S. saprophyticus, S. sciuri, S. simulans, S. warneri, and S. xylosus) inhibited growth of S. aureus in vitro, 23 isolates of which, from S. capitis, S. chromogenes, S. epidermidis, S. pasteuri, S. simulans, and S. xylosus, also inhibited MRSA. One hundred five putative bacteriocin gene clusters encompassing 6 different classes (lanthipeptides, sactipeptides, lasso peptides, class IIa, class IIc, and class IId) in 95 whole genomes from 16 species were identified. A total of 25 novel bacteriocin precursors were described. In conclusion, NAS from bovine mammary glands are a source of potential bacteriocins, with >21% being possible producers, representing potential for future characterization and prospective clinical applications. IMPORTANCE Mastitis (particularly infections caused by Staphylococcus aureus) costs Canadian dairy producers $400 million/year and is the leading cause of antibiotic use on dairy farms. With increasing antibiotic resistance and regulations regarding use, there is impetus to explore bacteriocins (bacterially produced antimicrobial peptides) for treatment and prevention of bacterial infections. We examined the ability of 441 NAS bacteria from Canadian bovine milk samples to inhibit growth of S. aureus in the laboratory. Overall, 9% inhibited growth of S. aureus and 58% of those also inhibited MRSA. In NAS whole-genome sequences, we identified >21% of NAS as having bacteriocin genes. Our study represents a foundation to further explore NAS bacteriocins for clinical use.

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In VitroEfficacies and Resistance Profiles of Rifampin-Based Combination Regimens for Biofilm-Embedded Methicillin-Resistant Staphylococcus aureus

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.01236-13 ◽

2013 ◽

Vol 57 (11) ◽

pp. 5717-5720 ◽

Cited By ~ 31

Author(s):

Hung-Jen Tang ◽

Chi-Chung Chen ◽

Kuo-Chen Cheng ◽

Kuan-Ying Wu ◽

Yi-Chung Lin ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Fusidic Acid ◽

Antibacterial Activities ◽

Methicillin Resistant ◽

Content Type ◽

Biofilm Model ◽

Rifampin Resistance ◽

Combination Regimens ◽

Resistant Mutation

ABSTRACTTo compare thein vitroantibacterial efficacies and resistance profiles of rifampin-based combinations against methicillin-resistantStaphylococcus aureus(MRSA) in a biofilm model, the antibacterial activities of vancomycin, teicoplanin, daptomycin, minocycline, linezolid, fusidic acid, fosfomycin, and tigecycline alone or in combination with rifampin against biofilm-embedded MRSA were measured. The rifampin-resistant mutation frequencies were evaluated. Of the rifampin-based combinations, rifampin enhances the antibacterial activities of and even synergizes with fusidic acid, tigecycline, and, to a lesser extent, linezolid, fosfomycin, and minocycline against biofilm-embedded MRSA. Such combinations with weaker rifampin resistance induction activities may provide a therapeutic advantage in MRSA biofilm-related infections.

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Impact of pH on growth of Staphylococcus epidermidis and Staphylococcus aureus in vitro

Journal of Medical Microbiology ◽

10.1099/jmm.0.001421 ◽

2021 ◽

Vol 70 (9) ◽

Author(s):

Vidula Iyer ◽

Janhavi Raut ◽

Anindya Dasgupta

Keyword(s):

Staphylococcus Aureus ◽

Growth Kinetics ◽

Staphylococcus Epidermidis ◽

Type Species ◽

Ph Dependence ◽

Skin Microbiome ◽

Content Type ◽

Link Type ◽

Kinetics Of

The pH of skin is critical for skin health and resilience and plays a key role in controlling the skin microbiome. It has been well reported that under dysbiotic conditions such as atopic dermatitis (AD), eczema, etc. there are significant aberrations of skin pH, along with a higher level of Staphylococcus aureus compared to the commensal Staphylococcus epidermidis on skin. To understand the effect of pH on the relative growth of S. epidermidis and S. aureus , we carried out simple in vitro growth kinetic studies of the individual microbes under varying pH conditions. We demonstrated that the growth kinetics of S. epidermidis is relatively insensitive to pH within the range of 5–7, while S. aureus shows a stronger pH dependence in that range. Gompertz’s model was used to fit the pH dependence of the growth kinetics of the two bacteria and showed that the equilibrium bacterial count of S. aureus was the more sensitive parameter. The switch in growth rate happens at a pH of 6.5–7. Our studies are in line with the general hypothesis that keeping the skin pH within an acidic range is advantageous in terms of keeping the skin microbiome in balance and maintaining healthy skin.

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