Antistaphylococcal Activity Research Articles

Use of encapsulated lactic acid bacteria as bioprotective cultures in fresh Brazilian cheese.

There is great interest for biopreservation of food products, and encapsulation may be a good strategy to extend the viability of protective cultures. In this study, Lactobacillus paraplantarum FT-259 and Lactococcus lactis QMF 11 were separately encapsulated in casein/pectin (C/P) microparticles, which were tested for antilisterial and anti-staphylococcal activity in fresh Minas cheese (FMC) stored at 8°C. The encapsulation efficiency for both lactic acid bacteria (LAB) was 82.5%, with viability over 6.2 log CFU/g after storage of C/P microparticles for 90days under refrigeration. Interestingly, free Lb. paraplantarum and free Lc. lactis grew significantly in refrigerated FMC, both in the presence and absence of pathogens, but only the first significatively grew when encapsulated. Encapsulation increased the antilisterial activity of Lb. paraplantarum in FMC. Moreover, Lc. lactis significantly inhibited listerial growth in FMC in both its free and encapsulated forms, whereas Staphylococcus aureus counts were only significantly reduced in the presence of free Lc. lactis. In conclusion, these results indicate that C/P microparticles are effective carriers of LAB in FMC, which can contribute for the assurance of the safety of this product.

Bioguided Isolation of Active Compounds from Rhamnus alaternus against Methicillin-Resistant Staphylococcus aureus (MRSA) and Panton-Valentine Leucocidin Positive Strains (MSSA-PVL).

Despite intensified efforts to develop an effective antibiotic, S. aureus is still a major cause of mortality and morbidity worldwide. The multidrug resistance of bacteria has considerably increased the difficulties of scientific research and the concomitant emergence of resistance is to be expected. In this study we have investigated the in vitro activity of 15 ethanol extracts prepared from Moroccan medicinal plants traditionally used for treatment of skin infections. Among the tested species I. viscosa, C. oxyacantha, R. tinctorum, A. herba alba, and B. hispanica showed moderate anti-staphylococcal activity. However, R. alaternus showed promising growth-inhibitory effects against specific pathogenic bacteria especially methicillin-susceptible Staphylococcus aureus Panton-Valentine leucocidin positive (MSSA-PVL) and methicillin-resistant S. aureus (MRSA). The bioguided fractionation of this plant using successive chromatographic separations followed by nuclear magnetic resonance (NMR) and mass spectrometry (MS) including EIMS and HREIMS analysis yielded the emodin (1) and kaempferol (2). Emodin being the most active with MICs ranging between 15.62 and 1.95 µg/mL and showing higher activity against the tested strains in comparison with the crude extract, its mechanism of action and the structure-activity relationship were interestingly discussed. The active compound has not displayed toxicity toward murine macrophage cells. The results obtained in the current study support the traditional uses of R. alaternus and suggest that this species could be a good source for the development of new anti-staphylococcal agents.

In Vitro Activity of Rifampin, Rifabutin, and Rifapentine against Enterococci and Streptococci from Periprosthetic Joint Infection.

ABSTRACTAfter staphylococci, streptococci and enterococci are the most frequent causes of periprosthetic joint infection (PJI). MICs and minimum biofilm bactericidal concentrations of rifampin, rifabutin, and rifapentine were determined for 67 enterococcal and 59 streptococcal PJI isolates. Eighty-eight isolates had rifampin MICs of ≤1 μg/ml, among which rifabutin and rifapentine MICs were ≤ 8 and ≤4 μg/ml, respectively. There was low rifamycin in vitro antibiofilm activity except for a subset of Streptococcus mitis group isolates.IMPORTANCE Rifampin is an antibiotic with antistaphylococcal biofilm activity used in the management of staphylococcal periprosthetic joint infection with irrigation and debridement with component retention; some patients are unable to receive rifampin due to drug interactions or intolerance. We recently showed rifabutin and rifapentine to have in vitro activity against planktonic and biofilm states of rifampin-susceptible periprosthetic joint infection-associated staphylococci. After staphylococci, streptococci and enterococci combined are the most common causes of periprosthetic joint infection. Here, we investigated the in vitro antibiofilm activity of rifampin, rifabutin, and rifapentine against 126 Streptococcus and Enterococcus periprosthetic joint infection isolates. In contrast to our prior findings with staphylococcal biofilms, there was low antibiofilm activity of rifampin, rifabutin, and rifapentine against PJI-associated streptococci and enterococci, apart from some Streptococcus mitis group isolates.

Evaluation of kinetic stability and anti-staphylococcal activity of recombinant LasA protein produced in Escherichia coli.

Objective(s):Staphylococcus aureus has become a major clinical concern due to the growing prevalence of multi-drug resistant (MDR) strains. Enzybioticts are peptidoglycan hydrolases that are recently introduced as an alternative agent to confront the MDR strains with a more effective mechanism than conventional antibiotics. In this regard, our study aimed to evaluate the kinetic stability of LasA protease as a potent enzybiotic in the specific destruction of the S. aureus cell wall. Materials and Methods:The catalytic domain of the Codon-optimized LasA gene was sub-cloned into pET28a vector, and BL21 DE3 cells were used for protein expression. Recombinant LasA protein was affinity purified by Ni-NTA column and staphylolytic activity of the LasA protein against methicillin-resistant strains was evaluated by disk diffusion and MIC test. The kinetic stability was evaluated in different temperatures during 48 hr. Results:Our results revealed that LasA protein can completely prevent the growth of Methicillin-resistant S. aureus (MRSA) strain and inhibit the examined strain at the amount of 4 µg. furthermore, the catalytic domain of LasA protein can tolerate higher temperatures as well. Conclusion:With regard to the failure of conventional antibiotics in treatment of MRSA infections, novel agents to combat multidrug-resistant strains are needed. The present study shows that LasA protein can eradicate MRSA strains, so it can be promising for the treatment of antibiotic-resistant staphylococci infection. The kinetic stability of LasA has also confirmed the possibility of industrial-scale manufacturing for the subsequent use of the enzyme clinically.

Antibacterial and anti-biofilm properties of Aptosimum albomarginatum(Marloth& Engl.) and Dicoma schinzii(O. Hoffm.) crude methanolic extracts against S. aureus and MRSA.

Background: The effectiveness of phytomedicine is often questioned by scientists. This study therefore aimed to test crude methanolic extracts from two traditional medicinal plants currently being used in Namibia for their antibacterial and anti-biofilm activity against Staphylococcus aureus and methicillin-resistant S. aureus (MRSA). Materials and methods: Aptosimum albomarginatum (Marloth & Engl.) roots and Dicoma schinzii (O. Hoffm.) roots and leaves were used to prepare crude methanolic extracts by maceration, filtration, rotary evaporation and freeze-drying. Thin layer chromatography (TLC) was used to detect flavonoids, saponins and anthraquinones in the plant material. For antibacterial activity, two S. aureus reference strains (one susceptible and one multi-drug resistant MRSA) and 10 S. aureus nasal isolates from school children were used in disk diffusion assays with crude methanolic plant extracts. The microtiter plate assay with crystal violet stain was used to determine if these extracts could inhibit and/or eradicate bacterial biofilms. Results: Aptosimum albomarginatum root extract displayed moderately antibacterial activity against five nasal isolates (one MRSA isolate) and two reference strains, of which one was multi-drug resistant MRSA. This extract was also the best biofilm inhibition agent, with highly active inhibition (86.0%) observed in S. aureus ATCC 33591 (MRSA). Dicoma schinzii root extract had moderate antibacterial activity against six nasal isolates and the two reference strains; its leaf extract was moderately active against two nasal isolates. The D. schinzii leaf extract moderately inhibited biofilms in two nasal isolates and S. aureus ATCC 25923. Flavonoids and saponins detected in both the roots and leaves of the two plants may have contributed to the extracts’ antibacterial and antibiofilm activity. Conclusion: Aptosimum albomarginatum roots and D. schinzii roots and leaves displayed anti-staphylococcal activity, indicating potential use against staphylococcal infections involving the bacteria under study. Noteworthy is both antibacterial and anti-biofilm properties of A. albomarginatum root extract against MRSA.

Perioperative antibiotic prophylaxis in surgery

Infectious complications in surgery occupy a significant place among the causes of death and increase in the cost of medical care for various pathologies. Antibiotic prophylaxis takes one of the first places in the perioperative period, in addition to surgical treatment and compliance with the rules of asepsis and antiseptics. Laxers is a new drug in the cephalosporin group, consisting of a combination of cefoperazone and sulbactam. It has a wide range of action on gram(-) and anaerobic flora and antistaphylococcal activity, which is not inferior to cefoperazone. Due to sulbactam, it has antimicrobial activity against Pseudomonas aeruginosa and Acinetobacter spp. This article describes the main properties and advantages of Laxers over other cephalosporins in this group as the drug of choice in the treatment of surgical pathologies and alternative antibiotic prophylaxis in the perioperative period in severe patients at risk of contamination of the operating field with hospital flora.

Antioxidant and anti-staphylococcal activity of polyphenolic-rich extracts from Ataulfo mango seed

In recent years, the search for new antioxidant and antimicrobial agents is one of the first subjects of scientific research. The polyphenolic compounds of food byproducts have attracted scientists across the world in the search for new natural substances. In this study, antioxidant (DPPH, ABTS, and TAA) and anti-Staphylococcus aureus (ATCC and clinical isolates strains) activity of mango seed extracts was investigated. The extracts were obtained by Microwave-Assisted Extraction (MAE), Fermentation-Assisted Extraction (FAE), and Solvent-Assisted Extraction (SAE). Chemical profile as well as influence of applied extraction technique were also investigated. The extracts showed potent antioxidant activity with EC50 values (MAE: 27.1 ± 0.15 μg/mL, SAE:14.3 ± 0.37 μg/mL and FAE:12.5 ± 0.41 μg/mL) higher than Trolox (for DPPH). Higher antibacterial activity was observed (MIC: 7.31–750 μg/mL and CMB: 156.3–1500 μg/mL) compared to synthetic antibiotics. Cell wall damage and cell lysis were clearly visualized under Scanning Electron Microscopy (SEM). HPLC–MS allowed the detection of 6 (SAE), 8 (MAE), and 11 (FAE) polyphenolic compounds. These findings suggest that Ataulfo mango seed extracts may be utilized in the developed natural antioxidant and antibacterial agents.

Detection of simultaneous production of kurstakin, fengycin and surfactin lipopeptides in Bacillus mojavensis using a novel gel-based method and MALDI-TOF spectrometry.

Bacterial lipopeptides have become a research focus of many studies owing to their industrial and pharmaceutical importance. Although such studies focused on researching purification procedures and qualitative analysis, much remains to be explored and developed to improve the current methods. To enable thorough studies of lipopeptides, this paper describes a new method for purification and characterization of in-gel anionic lipopeptides. Specifically, lipopeptides attributed to the anti-staphylococcal activity of Bacillus mojavensis HF were separated using SDS-PAGE (sodium dodecyl sulphate-polyacrylamide gel electrophoresis) and subsequently characterized using mass spectrometry. Lipopeptide band obtained by gel electrophoresis was first visualized using three different staining methods. Next, the lipopeptide isomers were efficiently recovered from the gel band and structural characterization of the extracted lipopeptides was carried out by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). MS analysis revealed that Bacillus mojavensis HF produced three types of lipopeptides including surfactin, fengycin, and kurstakin. 14 clusters of ion peaks were identified as fengycin A with fatty acid of C15-C17, fengycin B (C16, C17), surfactin (C13-C16), and kurstakin (C9-C12). Moreover, tandem mass spectrometric analysis (MS/MS) revealed the sequences of fengycin A and surfactin. In this study, we identified a high variety and number of surfactin and fengycin isomers, which previous reports lacked. To the best of our knowledge, we are the first to report the presence of kurstakin in Bacillus mojavensis species. Finally, we demonstrated that our gel-based study of lipopeptides allowed for a precise and reproducible investigation of these molecules.

Determination of MIC Quality Control Parameters for Exebacase, a Novel Lysin with Antistaphylococcal Activity.

ABSTRACTExebacase (CF-301), a novel, antistaphylococcal lysin (cell wall hydrolase) is the first agent of this class to enter late-stage clinical development (phase 3, NCT04160468) for the treatment of Staphylococcus aureus bacteremia, including right-sided endocarditis. A multilaboratory Clinical and Laboratory Standards Institute (CLSI) M23-defined tier 2 quality control (QC) study was conducted to establish exebacase QC ranges for a new reference broth microdilution method. S. aureus ATCC 29213 and Enterococcus faecalis ATCC 29212 were selected as reference QC strains. Broth microdilution MIC QC ranges for exebacase spanned 4 log2 dilutions and contained 99.2% of the MIC results generated for the two reference strains. The QC ranges for exebacase were defined as 0.25 to 2 μg/ml and 8 to 64 μg/ml against S. aureus ATCC 29213 and E. faecalis ATCC 29212, respectively, and were approved by the CLSI Subcommittee on Antimicrobial Susceptibility Testing. These QC ranges established for use with the reference broth microdilution method developed for exebacase susceptibility testing will ensure the test performance and accuracy of results generated during clinical development.

Development of a Broth Microdilution Method for Exebacase Susceptibility Testing

ABSTRACTExebacase (CF-301) belongs to a new class of protein-based antibacterial agents, known as lysins (peptidoglycan hydrolases). Exebacase, a novel lysin with antistaphylococcal activity, is in phase 3 of clinical development. To advance into the clinic, it was necessary to develop an accurate and reproducible method for exebacase MIC determination. The Clinical and Laboratory Standards Institute (CLSI) reference broth microdilution (BMD) method using cation-adjusted Mueller-Hinton broth (CAMHB) produced trailing MIC endpoints, and exebacase activity was diminished when frozen BMD panels were used. A modified BMD method was developed using CAMHB supplemented with 25% horse serum and 0.5 mM dl-dithiothreitol (CAMHB-HSD). Preliminary quality control (QC) ranges for Staphylococcus aureus ATCC 29213 of 0.25 to 1 μg/ml and for Enterococcus faecalis ATCC 29212 of 16 to 64 μg/ml were determined based on the results of a CLSI M23-defined MIC QC tier 1 study. These preliminary QC ranges validated the MIC data generated from a systematic study testing a discrete S. aureus strain collection using CAMHB-HSD to investigate the impact of parameters known to influence susceptibility test results and to evaluate the exebacase MIC distribution against clinical S. aureus isolates. Presentation of these data led to the CLSI Subcommittee on Antimicrobial Susceptibility Testing (AST) approval of the use of CAMHB-HSD to determine exebacase susceptibility and commencement of a multilaboratory (tier 2) QC study. Use of a standard BMD method and concomitant QC testing provides confidence in the assessment of test performance to generate accurate and reproducible susceptibility data during antibacterial drug development.

Multisubstituted pyrimidines effectively inhibit bacterial growth and biofilm formation of Staphylococcus aureus

Biofilms are multicellular communities of microorganisms that generally attach to surfaces in a self-produced matrix. Unlike planktonic cells, biofilms can withstand conventional antibiotics, causing significant challenges in the healthcare system. Currently, new chemical entities are urgently needed to develop novel anti-biofilm agents. In this study, we designed and synthesized a set of 2,4,5,6-tetrasubstituted pyrimidines and assessed their antibacterial activity against planktonic cells and biofilms formed by Staphylococcus aureus. Compounds 9e, 10d, and 10e displayed potent activity for inhibiting the onset of biofilm formation as well as for killing pre-formed biofilms of S. aureus ATCC 25923 and Newman strains, with half-maximal inhibitory concentration (IC50) values ranging from 11.6 to 62.0 µM. These pyrimidines, at 100 µM, not only decreased the number of viable bacteria within the pre-formed biofilm by 2–3 log10 but also reduced the amount of total biomass by 30–50%. Furthermore, these compounds were effective against planktonic cells with minimum inhibitory concentration (MIC) values lower than 60 µM for both staphylococcal strains. Compound 10d inhibited the growth of S. aureus ATCC 25923 in a concentration-dependent manner and displayed a bactericidal anti-staphylococcal activity. Taken together, our study highlights the value of multisubstituted pyrimidines to develop novel anti-biofilm agents.

In Vitro Anti-staphylococcal and Anti-inflammatory Abilities of Lacticaseibacillus rhamnosus from Infant Gut Microbiota as Potential Probiotic Against Infectious Women Mastitis.

Infectious mastitis is the major cause of early weaning, depriving infants of breastfeeding benefits. It is associated with an inflammatory condition of the breast and lowered resistance to infection. Drug administration during lactation often being contra-indicated, it is therefore important to consider safe therapeutic alternatives to antibiotic and anti-inflammatory therapies, such as probiotics. In this study, we investigated in vitro the probiotic potential of thirteen Lacticaseibacillus (formerly Lactobacillus) rhamnosus strains isolated from the gut microbiota of breastfed healthy infants. Strains were assessed for their β-hemolytic activity, their resistance to antibiotics, and their antimicrobial activities against strains of Staphylococcus and Streptococcus, most often involved in women mastitis. Their immunomodulating abilities were also studied using in vitro stimulation of human immune cells. None of the strains exhibited β-hemolytic activity, and all of them were sensitive to ampicillin, penicillin, tetracycline, rifampicin, erythromycin, chloramphenicol, and imipenem but showed resistance to ceftazidime, trimethoprim/sulfamethoxazole, vancomycin, and cefotaxime, reported to be chromosomally encoded and not inducible or transferable. Four L. rhamnosus strains were selected for their large anti-staphylococcal spectrum: L. rhamnosus VR1-5 and L. rhamnosus VR3-1 inhibiting S. aureus, S. epidermis, and S. warneri and L. rhamnosus CB9-2 and L. rhamnosus CB10-5 exerting antagonistic effect against S. aureus and S. epidermis strains. Antimicrobial compounds released in cell-free supernatant showed proteinaceous nature and were thermoresistant. The immune modulatory analysis of the L. rhamnosus strains revealed two strains with significant anti-inflammatory potential, highlighted by strong induction of IL-10 and a weak pro-Th1 cytokine secretion (IL-12 and IFN-γ). L. rhamnosus CB9-2 combined a large anti-staphylococcal activity spectrum and a promising anti-inflammatory profile. This strain, used individually or in a mixture, can be considered as a probiotic candidate for the management of infectious mastitis during lactation.

Anti-staphylococcal activity, cytotoxicity, and chemical composition of hexane extracts from arils and seeds of two Samoan Myristica spp

Hexane extracts derived from the arils and seeds of two Samoan indigenous plant species, Myristica hypargyraea A. Gray and Myristica inutilis Rich ex A. Gray, were assessed for their in vitro anti-staphylococcal effect using a broth microdilution assay. Additionally, their cytotoxic activity against human colon cancer and normal intestinal cell lines was determined. In this study, all plant extracts tested showed a certain degree of growth-inhibitory effect against various strains of Staphylococcus aureus with minimum inhibitory concentrations (MICs) ranging from 8 to 1,024 µg/mL. The aril extract of M. hypargyraea possessed the highest antibacterial activity with MIC value 8 µg/mL against one standard strain and three clinical isolates of S. aureus, the effective concentrations of this extract were found to be safe for the intestinal cells. The aril extract of M. inutilis showed the highest selective antiproliferative effect on intestinal cancer cells with a lower toxicity to normal cell lines. Using gas chromatography-mass spectrometry analysis, malabaricone A, otobain, licarin A, and licarin B were identified as the major components of both the aril and seed extracts of M. hypargyraea and M. inutilis.

Therapeutic applications of lysostaphin against Staphylococcus aureus.

Staphylococcus aureus, an opportunistic pathogen, causes diverse community and nosocomial-acquired human infections, including folliculitis, impetigo, sepsis, septic arthritis, endocarditis, osteomyelitis, implant-associated biofilm infections and contagious mastitis in cattle. In recent days, both methicillin-sensitive and methicillin-resistant S. aureus infections have increased. Highly effective anti-staphylococcal agents are urgently required. Lysostaphin is a 27kDa zinc metallo antimicrobial lytic enzyme that is produced by Staphylococcus simulans biovar staphylolyticus and was first discovered in the 1960s. Lysostaphin is highly active against S. aureus strains irrespective of their drug-resistant patterns with a minimum inhibitory concentration of ranges between 0·001 and 0·064μgml-1 . Lysostaphin has activity against both dividing and non-dividing S. aureus cells; and can seep through the extracellular matrix to kill the biofilm embedded S. aureus. In spite of having excellent anti-staphylococcal activity, its clinical application is hindered because of its immunogenicity and reduced bio-availability. Extensive research with lysostaphin lead to the development of several engineered lysostaphin derivatives with reduced immunogenicity and increased serum half-life. Therapeutic efficacy of both native and engineered lysostaphin derivatives was studied by several research groups. This review provides an overview of the therapeutic applications of native and engineered lysostaphin derivatives developed to eradicate S. aureus infections.

Antioxidant, anti-inflammatory, and anti-Staphylococcal activities of Albizia lucidior (Steud.) I. C. Nielsen wood extracts

Antioxidant, anti-inflammatory, and anti-Staphylococcal activities of Albizia lucidior (Steud.) I. C. Nielsen wood extracts

THE EFFECT OF SANGUIRITRINUM ON THE PATHOGENICITY FACTORS OF METHICILLIN-RESISTANT STAPHYLOCOCCUS AUREUS

The relevance of the problem. The frequency of growth of staphylococcal infections in human pathology and the decrease in the effectiveness of their treatment, due to the formation of multidrug resistance, has aroused interest in the study of the anti-staphylococcal activity of Sanguiritrinum and its effect on biological properties, including certain pathogenic factors. The aim of the research was to study the effect of Sanguiritrinum on the pathogenicity factors of the archival strain and clinical isolate of methicillin-resistant S. aureus. Materials and methods. The objects of the study were the reference strain of Staphylococcus aureus ATCC 25923 from the Museum of Living Cultures of Microorganisms of the Department of Microbiology, Virology and Immunology, Poltava State Medical University, and clinical isolate of S. aureus isolated from patients of the surgical department and identified by standard methods. The resistance of this isolate to methicillin was determined using the disk-diffusion method, after which it was concluded that the strain of Staphylococcus aureus belongs to MRSA. In order to assess the antimicrobial activity of the phytopreparation Sanguiritrinum against the studied clinical and archival strains, we used the quantitative method of double serial dilutions in a liquid medium and qualitative disk-diffusion method (Kirby­–Bauer) according to standard methods, in compliance with the Order of the Ministry of Public Health of Ukraine No.167 as of 05.04.2007 on the statement of methodical instructions "Determination of sensitivity of microorganisms to antibacterial drugs". Studies of the effect of Sanguiritrinum on the pathogenicity of S. aureus were performed by assessing the plasma-coagulating, lecithovitelase and hemolytic activity of microorganisms in the presence of plant extract according to conventional methods. Conclusions. The obtained data substantiate the prospects of using Sanguiritrinum in the prevention and treatment of purulent and inflammatory diseases of staphylococcal etiology, including infections caused by methicillin-resistant strains of S. aureus. The phytopreparation Sanguiritrinum has a strong bacteriostatic effect on the reference strain and on the MRSA clinical isolate of S. aureus. Naturally, the clinical isolate of S. aureus with methicillin resistance was characterized by lower sensitivity to the action of Sanguiritrinum, as compared to the sensitivity of the archival strain, because the bactericidal concentration of the drug was 2 times higher. Sanguiritrinum at a concentration of 0.06 μg/ml resulted in complete loss of pathogenicity factors (plasma coagulation, lecithovitelase and hemolytic activity) of the reference strain and the MRSA clinical isolate of S. aureus. At a phytopreparation concentration of 0.03 μg/ml, the microorganisms lost only plasma coagulation ability.

1259. Activity of eravacycline against staphylococci isolated from periprosthetic joint infections

BackgroundPerirosthetic joint infections (PJIs) are costly and difficult to treat. The most common causes of PJIs are Staphylococcus aureus and Staphylococcus epidermidis. Eravacycline is a newer tetracycline with promising activity against Gram-positive and negative bacteria which is approved for treatment of complicated intraabdominal infections. Here, the in vitro activity of eravacycline was assessed against bacteria associated with PJI.Methods185 staphylococcal isolates, including 38 methicillin-resistant S. aureus (MRSA), 64 methicillin-susceptible S. aureus (MSSA), 62 methicillin-resistant S. epidermidis (MRSE) and 21 methicillin-susceptible S. epidermidis (MSSE) strains were studied. Minimum inhibitory concentrations (MICs) were determined according to Clinical and Laboratory Standards Institute guidelines (range of 0.06-64 µg/ml tested). Results were analyzed using susceptible breakpoints from EUCAST (≤0.25 µg/ml) and the FDA (≤0.06 µg/ml). Minimum biofilm bactericidal concentrations (MBBCs) were determined using a modification of the Calgary biofilm method. Briefly, biofilms were formed on pegged lids in trypticase soy broth, after which the pegged lids were rinsed in phosphate buffered saline (PBS), transferred to a plate containing dilutions of eravacycline in cation-adjusted Mueller Hinton broth (CAMHB) and incubated for 20-24h. Finally, the pegged lids were again rinsed in PBS and transferred to a plate containing CAMHB and incubated for 24h. The MBBC was the lowest concentration with no visible growth.ResultsMIC50/90 (range) in µg/ml for MRSA, MSSA, MRSE, and MSSE were 0.125/0.125 (≤0.06-0.25), ≤0.06/0.125 (≤0.06-0.25). 0.125/1 (≤0.06-2), and 0.25/1 (≤0.06-1), respectively. Using the EUCAST susceptible breakpoint, 100% of isolates would be considered susceptible, whereas only 54% would be considered susceptible using the FDA breakpoint. MBBC50/90 (range) in µg/ml for MRSA and MSSA were both 8/16 (4-16); for MRSE and MSSE, the values were 4/16 (2-32) and 8/16 (2-32), respectively.ConclusionOur data suggest that the FDA susceptible breakpoint may need re-evaluation. Eravacycline has low anti-staphylococcal biofilm activity.DisclosuresRobin Patel, MD, Accelerate Diagnostics (Grant/Research Support)CD Diagnostics (Grant/Research Support)Contrafect (Grant/Research Support)Curetis (Consultant)GenMark Diagnostics (Consultant)Heraeus Medical (Consultant)Hutchison Biofilm Medical Solutions (Grant/Research Support)Merck (Grant/Research Support)Next Gen Diagnostics (Consultant)PathoQuest (Consultant)Qvella (Consultant)Samsung (Other Financial or Material Support, Dr. Patel has a patent on Bordetella pertussis/parapertussis PCR issued, a patent on a device/method for sonication with royalties paid by Samsung to Mayo Clinic, and a patent on an anti-biofilm substance issued.)Selux Dx (Consultant)Shionogi (Grant/Research Support)Specific Technologies (Consultant)

Current Issues of Empirical Therapy of Severe Bacterial Community-Acquired Pneumonia During the Season of Respiratory Viral Infections

Progredient growth of morbidity and mortality of patients with community-acquired pneumonia (CAP) requires optimization of treatment including antibacterial therapy. Implementation of molecular-genetic methods of diagnostics of viral and viral-bacterial infections in clinical practice has significantly augmented the conception of etiology of community-acquired pneumonia. Seasonal fluctuation of CAP prevalence corresponds with growth of morbidity of acute respiratory infections and influenza which contribute to the etiological structure of CAP by increasing the risk of infection caused by staphylococci. The synergy between influenza A virus and S.aureus has been shown; it is associated with an increase of virus replication in the presence of specific staphylococcal proteases and the ability of viruses to increase adhesion of S.aureusin the respiratory tract, to decrease phagocytosis of S.aureus by macrophages/neutrophils and production of antimicrobial peptides, as well as to increase the probability of secondary bacterial co-infection. Therefore, the most important requirement for the empiric therapy agents of CAP is high streptococcal and staphylococcal activity. According to the current guidelines on antimicrobial therapy of severe CAP, antipneumococcic cephalosporins, macrolides, and fluoroquinolones are the basic treatment agents, but none of them have the combined high antistaphylococcal and antipneumococcal activity inherent in ceftaroline. The advantages of ceftaroline over ceftriaxone and levofloxacin in terms of the probability of reaching target concentrations for clinically relevant pharmacokinetic/pharmacodynamic parameters are shown. Meta-analysis of randomized clinical trials showed the higher clinical efficacy of ceftaroline in comparison to ceftriaxone with similar adverse event rate. Summarized analysis of antibiotic susceptibility data, pharmacokinetic/pharmacodynamic and clinical data, as well as negative epidemiological trends confirms the necessity of optimization of antimicrobial therapy of CAP for implementation of ceftaroline advantages against pneumococci and staphylococci in comparison to other β-lactams. Therefore, empiric treatment with ceftaroline is the most rational option for the therapy of CAP in critically ill patients during the season of respiratory viral infection.

English

Capsicum fructescens is a variety of Capsicum with much nutritional and therapeutic usefulness. This study is aimed at investigating the antimicrobial, chemical and biochemical properties of C. fructescens. The biochemical, mineral and phytochemical analyses of the extract were carried out using standard methods. The organic contents of the extracts were determined by GCMS to identify its bioactive constituents which were tested for antibacterial and antifungal activities against 7 bacterial and 3 fungal isolates using disc-diffusion method. The biochemical analysis showed that the leaves were high in protein, fibre, carbohydrate and fat. Different mineral elements were detected in the leaves and they include Magnesium, Calcium, Iron, Sodium, Copper, Potassium, Zinc and Manganese. GC-MS revealed 13 different organic compounds belonging to four groups of chemicals namely alkanol, alkanoic acid, alkanoate and ester. The methanolic extracts of C. fructescens leaves at a dose range of 5 and 25 mg/ml showed significant antibacterial and antifungal activity on some test organisms. The presence of great quantity of dodecanoic acid among other compounds in the extract of bawa suggested the reason for its profound anti-staphylococcal and anti-candidal activities. This study concluded that C. fructescens foliar extract is rich in important chemical and biochemical metabolites which have shown some therapeutic properties. An advocacy in the higher consumption of these peppers among folks is hereby recommended.   Key words: Capsicum fructescens extracts, chemicals and biochemical composition, antimicrobial activity.

Could Supercritical Extracts from the Aerial Parts of Helianthus salicifolius A. Dietr. and Helianthus tuberosus L. Be Regarded as Potential Raw Materials for Biocidal Purposes?

Extracts from the June collection of aerial parts of Helianthus salicifolius A. Dietr and Helianthus tuberosus L. were obtained using carbon dioxide supercritical fluid extraction with water as co-solvent. The antimicrobial effect in vitro of these extracts was then determined against reference species of bacteria, as well as against fungi (represented by Candida spp.). Both extracts were found to possess antimicrobial activity, with MIC = 0.62–5 mg mL−1 for bacteria and MIC = 5–10 mg mL−1 for yeasts, and both extracts demonstrated suitable bactericidal and fungicidal effect. The highest activity was observed against S. aureus ATCC 29213 (MIC = 0.62 mg mL−1 for H. salicifolius extract; MIC = 2.5 mg mL−1 for H. tuberosus extract) as confirmed by time–kill assay. Higher antioxidant activity was found for H. tuberosus extract (EC50 = 0.332 mg mL−1) as compared to that of H. salicifolius (EC50 = 0.609 mg mL−1). The total polyphenol content (TPC) expressed as gallic acid equivalents (GAE) was 13.75 ± 0.50 mg GAE g−1 of H. salicifolius extract and 33.06 ± 0.80 mg GAE g−1 of H. tuberosus extract. There was a relationship between the antioxidant potential of both extracts and TPC, but not between antistaphylococcal activity and TPC. The ATIR–FTIR spectra of both extracts showed similar main vibrations of the functional groups typical for phytoconstituents possessing bioactivity. The obtained data suggest potential application of these extracts as natural antioxidants and preparations with biocidal activity. Additionally, both extracts may be regarded as potential natural conservants in cosmetics, as well as natural preservatives in food.