scholarly journals Characterization of vB_Sau_S90, and vB_Sau_S165, a Broad Host Range Phages, and Multiple Phage Doses as a Potential Therapeutic Strategy to Eliminate Transient Phage Resistant Mutants in Staphylococcus Aureus

2021 ◽  
Author(s):  
Archana Loganathan ◽  
Ramesh Nachimuthu
Keyword(s):  
Staphylococcus Aureus ◽  
Host Range ◽  
Serial Passage ◽  
Broad Host Range ◽  
Bacterial Cells ◽  
Bacterial Killing ◽  
Methicillin Resistant ◽  
Adsorption Time ◽  
Wide Range

Abstract Methicillin-Resistant Staphylococcus aureus is a human pathogen. MRSA has acquired resistance to major antibiotics; thus, phage therapy has become a potential alternative treatment. In this work, two broad host range Staphylococcus phages were characterized for lifecycle, physio-chemical parameters and bacterial killing kinetics, and the in vitro behavior of phage insensitive bacterial cells to alternative serial passage and multiple phage doses were assessed by reduction in the bacterial turbidity and spot assay. Phage vB_Sau_S90 showed an absorption efficiency of 91 ± 0.6% with an adsorption time of 17 ± 1 min and vB_Sau_S165 of 95 ± 0.5% adsorption efficiency and 15 ± 2 min adsorption time. Both the phages were stable over a wide range of temperature (20 to 50 ℃) and pH (3 to 11). vB_Sau_S90 phage belonging to the family Siphoviridae [order Caudovirals] showed killing efficiency against 88% (181/205) of S. aureus isolates, and vB_Sau_S165 belonging to family Podoviridae [order Caudovirals] showed killing efficiency against 94% (192/205) of S. aureus isolates. The sensitive and transient phage-resistant cells that remained uninfected during the single dose of phage treatment were eliminated upon a minimum of five alternative serial passage and multiple phage doses. This study concludes that both the phages showed promising activity against methicillin-resistant Staphylococcus aureus. Our study revealed that despite phage auto-dosing and high therapeutic efficiency, both phages did not produce a complete bacterial clearance at a single phage dose; hence indicated that multiple phage doses were required to attain a successful and complete bacterial eradication.

scholarly journals Revealing biophysical properties of KfrA-type proteins as a novel class of cytoskeletal, coiled-coil plasmid-encoded proteins

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
M. Adamczyk ◽  
E. Lewicka ◽  
R. Szatkowska ◽  
H. Nieznanska ◽  
J. Ludwiczak ◽  
...  
Keyword(s):  
Dna Binding ◽  
Host Range ◽  
Coiled Coil ◽  
Amino Acid Sequences ◽  
Broad Host Range ◽  
Biophysical Properties ◽  
Dna Binding Sites ◽  
In Silico Studies ◽  
Wide Range

Abstract Background DNA binding KfrA-type proteins of broad-host-range bacterial plasmids belonging to IncP-1 and IncU incompatibility groups are characterized by globular N-terminal head domains and long alpha-helical coiled-coil tails. They have been shown to act as transcriptional auto-regulators. Results This study was focused on two members of the growing family of KfrA-type proteins encoded by the broad-host-range plasmids, R751 of IncP-1β and RA3 of IncU groups. Comparative in vitro and in silico studies on KfrAR751 and KfrARA3 confirmed their similar biophysical properties despite low conservation of the amino acid sequences. They form a wide range of oligomeric forms in vitro and, in the presence of their cognate DNA binding sites, they polymerize into the higher order filaments visualized as “threads” by negative staining electron microscopy. The studies revealed also temperature-dependent changes in the coiled-coil segment of KfrA proteins that is involved in the stabilization of dimers required for DNA interactions. Conclusion KfrAR751 and KfrARA3 are structural homologues. We postulate that KfrA type proteins have moonlighting activity. They not only act as transcriptional auto-regulators but form cytoskeletal structures, which might facilitate plasmid DNA delivery and positioning in the cells before cell division, involving thermal energy.

scholarly journals Characterization of a Novel Bacteriophage Henu2 and Evaluation of the Synergistic Antibacterial Activity of Phage-Antibiotics

Antibiotics ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 174
Author(s):  
Xianghui Li ◽  
Tongxin Hu ◽  
Jiacun Wei ◽  
Yuhua He ◽  
Abualgasim Elgaili Abdalla ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Burst Size ◽  
Open Reading Frames ◽  
Comparative Genomic ◽  
Sewage Sample ◽  
Bacterial Killing ◽  
Wide Range ◽  
The Family ◽  
Infected Cells

Staphylococcus aureus phage Henu2 was isolated from a sewage sample collected in Kaifeng, China, in 2017. In this study, Henu2, a linear double-stranded DNA virus, was sequenced and found to be 43,513 bp long with 35% G + C content and 63 putative open reading frames (ORFs). Phage Henu2 belongs to the family Siphoviridae and possesses an isometric head (63 nm in diameter). The latent time and burst size of Henu2 were approximately 20 min and 7.8 plaque forming unit (PFU)/infected cells. The Henu2 maintained infectivity over a wide range of temperature (10–60 °C) and pH values (4–12). Phylogenetic and comparative genomic analyses indicate that Staphylococcus aureus phage Henu2 should be a new member of the family of Siphoviridae class-II. In this paper, Phage Henu2 alone exhibited weak inhibitory activity on the growth of S. aureus. However, the combination of phage Henu2 and some antibiotics or oxides could effectively inhibit the growth of S. aureus, with a decrease of more than three logs within 24 h in vitro. These results provide useful information that phage Henu2 can be combined with antibiotics to increase the production of phage Henu2 and thus enhance the efficacy of bacterial killing.

scholarly journals In VitroPharmacodynamics of Vancomycin and Cefazolin Alone and in Combination against Methicillin-Resistant Staphylococcus aureus

2011 ◽  
Vol 56 (1) ◽  
pp. 202-207 ◽  
Author(s):  
Mao Hagihara ◽  
Dora E. Wiskirchen ◽  
Joseph L. Kuti ◽  
David P. Nicolau
Keyword(s):  
Staphylococcus Aureus ◽  
Combination Therapy ◽  
Synergistic Effects ◽  
Bacterial Density ◽  
Bacterial Killing ◽  
Methicillin Resistant ◽  
Content Type ◽  
Vancomycin Mics ◽  
Time Kill

ABSTRACTPrevious studies employing time-kill methods have observed synergistic effects against methicillin-resistantStaphylococcus aureus(MRSA) when a β-lactam is combined with vancomycin. However, these time-kill studies have neglected the importance of human-simulated exposures. We evaluated the effect of human simulated exposures of vancomycin at 1 g every 8 h (q8h) in combination with cefazolin at 1 g q8h against various MRSA isolates. Four clinical isolates (two MRSA isolates [vancomycin MICs, 0.5 and 2.0 μg/ml], a heterogeneous vancomycin-intermediateS. aureus[hVISA] isolate [MIC, 2.0 μg/ml], and a vancomycin-intermediateS. aureus[VISA] isolate [MIC, 8.0 μg/ml]) were evaluated in anin vitropharmacodynamic model with a starting inoculum of 106or 108CFU/ml. Bacterial density was measured over 48 to 72 h. Time-kill curves were constructed, and the area under the bacterial killing and regrowth curve (AUBC) was calculated. During 106CFU/ml studies, combination therapy achieved greater log10CFU/ml changes than vancomycin alone at 12 h (−4.31 ± 0.58 versus −2.80 ± 0.59,P< 0.001), but not at 48 h. Combination therapy significantly reduced the AUBC from 0 to 48 h (122 ± 14) compared with vancomycin alone (148 ± 22,P= 0.017). Similar results were observed during 108CFU/ml studies, where combination therapy achieved greater log10CFU/ml changes at 12 h than vancomycin alone (−4.00 ± 0.20 versus −1.10 ± 0.04,P< 0.001) and significantly reduced the AUBC (275 ± 30 versus 429 ± 37,P< 0.001) after 72 h of incubation. In this study, the combination of vancomycin and cefazolin at human-simulated exposures improved the rate of kill against these MRSA isolates and resulted in greater overall antibacterial effect, but no differences in bacterial density were observed by the end of the experiments.

scholarly journals Comparison of Effectiveness of Germania Honey Compared to Manuka Honey in Methicillin-Resistant Staphylococcus aureus (MRSA) Killing

2019 ◽  
Vol 13 (1) ◽  
pp. 21-27 ◽  
Author(s):  
Ali M. Bazzi ◽  
Ali A. Rabaan ◽  
Jaffar A. Al-Tawfiq ◽  
Bilal M. Shannak
Keyword(s):  
Staphylococcus Aureus ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Bacterial Species ◽  
Wound Dressings ◽  
Manuka Honey ◽  
Bacterial Killing ◽  
Methicillin Resistant ◽  
Wound Culture ◽  
Comparison Of Effectiveness

Purpose: Manuka honey is currently used in medical-grade sterile wound treatment products and has been shown to be effective in methicillin-resistant Staphylococcus aureus (MRSA) killing in vitro and in wound healing in a number of case studies and series. Locally produced honey in Pakistan and Chile have been proposed to be as effective as Manuka honey in bacterial killing in vitro, presenting potentially more accessible and affordable alternatives. In this study, we compared the effectiveness of a local Germania honey from Saudi Arabia to Manuka honey MGO 550 for in vitro killing of MRSA. Methodology: Overnight Muller Hinton broth cultures of 50 wound culture isolates of MRSA from 50 patients were incubated with a series of dilutions of Manuka honey MGO 550 and corresponding Germania honey dilutions for 24 h. Turbidity was assessed to determine whether bacterial growth had occurred, and no growth was confirmed by a further 24 h sub-culture on blood agar. Results/Key findings: Manuka honey MGO 550 was significantly more effective than Germania honey at MRSA killing at 100% v/v, 50% v/v and 25% v/v (p=0.025, 0.000265, and 0.000112 respectively) Conclusion: Manuka honey MGO 550 is significantly more effective in killing MRSA in vitro than Germania honey. Germania honey does not appear to be a promising locally produced alternative to Manuka honey for the development of honey-based wound dressings. Further experiments could determine if Germania honey is effective against other bacterial species.

scholarly journals In Vitro Susceptibility of Methicillin-Resistant Staphylococcus aureus and Methicillin-Susceptible Staphylococcus aureus to a New Antimicrobial, Copper Silicate

2007 ◽  
Vol 51 (12) ◽  
pp. 4505-4507 ◽  
Author(s):  
Kerry C. Carson ◽  
Jessica G. Bartlett ◽  
Trina-Jean Tan ◽  
Thomas V. Riley
Keyword(s):  
Staphylococcus Aureus ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Serial Passage ◽  
In Vitro Susceptibility ◽  
Methicillin Resistant ◽  
Copper Silicate

ABSTRACT The soluble copper silicate (CS) MIC of 100 strains of methicillin-resistant Staphylococcus aureus and 100 strains of methicillin-susceptible S. aureus (MSSA) was 175 mg Cu/liter. Bactericidal and postantibiotic effects (≥1 h) were seen at 2× MIC and 4× MIC. The frequency of mutation was <10−9, and serial passage could not extend growth beyond 1.6× MIC.

scholarly journals Antimicrobial activity of SM-17466, a novel carbapenem antibiotic with potent activity against methicillin-resistant Staphylococcus aureus.

1995 ◽  
Vol 39 (4) ◽  
pp. 910-916 ◽  
Author(s):  
Y Sumita ◽  
H Nouda ◽  
K Kanazawa ◽  
M Fukasawa
Keyword(s):  
Staphylococcus Aureus ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Inhibitory Concentration ◽  
Antibacterial Activities ◽  
Infection Model ◽  
Methicillin Resistant ◽  
Gram Positive Bacteria ◽  
Wide Range

The in vitro and in vivo antibacterial activities of SM-17466, a new 1 beta-methyl carbapenem, were evaluated against a wide range of clinical bacterial isoaltes and compared with the activities of meropenem, imipenem, vancomycin, and arbekacin. SM-17466 had a broad spectrum of action against gram-positive bacteria, showing especially potent activity against methicillin-resistant staphylococci. The MICs of SM-17466, meropenem, imipenem, vancomycin, and arbekacin at which 90% of clinical isolates of methicillin-resistant Staphylococcus aureus were inhibited were 3.13, 50, 100, 1.56, and 3.13 micrograms/ml, respectively. This activity of SM-17466 was almost equivalent to those of the antibiotics used for the treatment of infections caused by this organism. SM-17466 also showed bactericidal activity against methicillin-resistant S. aureus. In contrast, SM-17466 was less active against gram-negative bacteria, especially against Pseudomonas aeruginosa, compared with the other carbapenems; however, of the carbapenems, SM-17466 exhibited the highest activity against Haemophilus influenzae and Bacteriodes fragilis. SM-17466, at a 50% inhibitory concentration of less than 1 microgram/ml, bound to penicillin-binding proteins 1 to 4 in methicillin-susceptible S. aureus and also had good binding to penicillin-binding protein 2' in a methicillin-resistant strain (50% inhibitory concentration, 5.9 micrograms/ml). This high affinity, which was 10 and 20 times greater than those for meropenem and imipenem, respectively, was reflected in the potent activity of SM-17466 against methicillin-resistant S. aureus. SM-17466 demonstrated excellent in vivo efficacy against methicillin-susceptible and -resistant S. aureus strains in a mouse peritoneal infection model: the efficacy of SM-17466 against methicillin-resistant strains was equal to or one-third that of vancomycin. This activity was comparable to the in vitro activity of SM-17466. The subcutaneous injection of SM-17466 in mice revealed that the half-life of SM-17466 in serum was about 18 min, intermediate between those of vancomycin and arbekacin and 1.5-fold that of imipenem-cilastatin. SM-17466 was resistant to hydrolysis by swine renal dehydropeptidase I, to an extent comparable to the resistance shown by meropenem.

scholarly journals Performance of vancomycin and teicoplanin disk diffusion test in isogenic vancomycin non-susceptible Staphylococcus aureus

2015 ◽  
Vol 9 (02) ◽  
pp. 157-164 ◽  
Author(s):  
Sujintana Wongthong ◽  
Karnjana Dutchanutouch ◽  
Viladda Namsaengkang ◽  
Aroonwadee Chanawong ◽  
Chotechana Wilailuckana ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Predictive Value ◽  
Population Analysis ◽  
Area Under The Curve ◽  
Serial Passage ◽  
Disk Diffusion ◽  
Diffusion Test ◽  
Disk Diffusion Test ◽  
Methicillin Resistant

Introduction: Detection of heterogeneous vancomycin-intermediate Staphylococcus aureus (hVISA) is currently problematic. Although the population analysis profile with area under the curve (PAP-AUC) is the gold standard for detecting hVISA strains, this method is time consuming. This study aimed to induce vancomycin non-susceptible Staphylococcus aureus isolates in methicillin-resistant S. aureus (MRSA) and to determine the performance of the vancomycin and teicoplanin disk diffusion test for screening of induced and natural vancomycin non-susceptible isolates. Methodology: Vancomycin resistance was induced in vitro in methicillin-resistant S. aureus by serial passage in media with increasing vancomycin concentrations. All test isolates were confirmed for their susceptibility to vancomycin by using a PAP-AUC method. The performance of the vancomycin and teicoplanin disk diffusion test for detecting both induced and natural hVISA/VISA isolates was analyzed using the MedCal program version 10.2.0. Results: The induction test revealed that 42 of 78 MRSA isolates (53.8%) became hVISA and/or VISA. Using 10, 15, 20, 30 µg vancomycin disks and a 30 µg teicoplanin disk, the highest performance (88.9%) for hVISA/VISA detection (71.1%, sensitivity, 100% specificity, 100% positive predictive value, and 75% negative predictive value) was obtained when a 20 µg vancomycin disk was used at 1.0 McFarland inoculum for a 24-hour incubation. Conclusions: The results indicated that using a 20 µg vancomycin disk and bacterial inoculum of 1.0 McFarland is simple to perform and provides a primary result for hVISA/VISA screening within 24 hours.

scholarly journals Evaluation of Ceftaroline Activity against Heteroresistant Vancomycin-Intermediate Staphylococcus aureus and Vancomycin-Intermediate Methicillin-Resistant S. aureus Strains in anIn VitroPharmacokinetic/Pharmacodynamic Model: Exploring the “Seesaw Effect”

2013 ◽  
Vol 57 (6) ◽  
pp. 2664-2668 ◽  
Author(s):  
Brian J. Werth ◽  
Molly E. Steed ◽  
Glenn W. Kaatz ◽  
Michael J. Rybak
Keyword(s):  
Staphylococcus Aureus ◽  
Pharmacokinetic Parameters ◽  
Bacterial Killing ◽  
Methicillin Resistant ◽  
Content Type ◽  
Penicillin Binding Proteins ◽  
Development Of Resistance ◽  
Mutant Strains ◽  
Mrsa Strains

ABSTRACTA “seesaw effect” in methicillin-resistantStaphylococcus aureus(MRSA) has been demonstrated, whereby susceptibility to β-lactam antimicrobials increases as glyco- and lipopeptide susceptibility decreases. We investigated this effect by evaluating the activity of the anti-MRSA cephalosporin ceftaroline against isogenic pairs of MRSA strains with various susceptibilities to vancomycin in anin vitropharmacokinetic/pharmacodynamic (PK/PD) model. The activities of ceftaroline at 600 mg every 12 h (q12h) (targeted free maximum concentration of drug in serum [fCmax], 15.2 μg/ml; half-life [t1/2], 2.3 h) and vancomycin at 1 g q12h (targetedfCmax, 18 μg/ml;t1/2, 6 h) were evaluated against 3 pairs of isogenic clinical strains of MRSA that developed increased MICs to vancomycin in patients while on therapy using a two-compartment hollow-fiber PK/PD model with a starting inoculum of ∼107CFU/ml over a 96-h period. Bacterial killing and development of resistance were evaluated. Expression of penicillin-binding proteins (PBPs) 2 and 4 was evaluated by reverse transcription (RT)-PCR. The achieved pharmacokinetic parameters were 98 to 119% of the targeted values. Ceftaroline and vancomycin were bactericidal against 5/6 and 1/6 strains, respectively, at 96 h. Ceftaroline was more active against the mutant strains than the parent strains, with this difference being statistically significant for 2/3 strain pairs at 96 h. The level of PBP2 expression was 4.4× higher in the vancomycin-intermediateS. aureus(VISA) strain in 1/3 pairs. The levels of PBP2 and PBP4 expression were otherwise similar between the parent and mutant strains. These data support the seesaw hypothesis that ceftaroline, like traditional β-lactams, is more active against strains that are less susceptible to vancomycin even when the ceftaroline MICs are identical. Further research to explore these unique findings is warranted.

Silviavirus phage ɸMR003 displays a broad host range against methicillin-resistant Staphylococcus aureus of human origin

2019 ◽  
Vol 103 (18) ◽  
pp. 7751-7765 ◽  
Author(s):  
Chanthol Peng ◽  
Tomoko Hanawa ◽  
Aa Haeruman Azam ◽  
Cierra LeBlanc ◽  
Porsry Ung ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Host Range ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Broad Host Range ◽  
Human Origin ◽  
Methicillin Resistant
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