scholarly journals Changes in Antibiotic Susceptibility Pattern of Atypical Staphylococcus Aureus Strains Isolated from Cows of the same Herd in 2008-2010

2012 ◽  
Vol 56 (2) ◽  
pp. 139-143
Author(s):  
Magdalena Małkińska-Horodyska ◽  
Joanna Kubiak ◽  
Henryka Lassa ◽  
Edward Malinowski
Keyword(s):  
Staphylococcus Aureus ◽  
Methicillin Resistance ◽  
Penicillin G ◽  
Diffusion Method ◽  
Conventional Pcr ◽  
Antibiotic Susceptibility Pattern ◽  
Microdilution Method ◽  
Resistant Strains ◽  
One Year

Abstract The isolates of Staphylococcus aureus strains were examined phenotypically by cultural features, tube coagulase test and clumping factor (CF), and genotypically by conventional PCR. The strains had positive reaction in CF test, but were negative in tube coagulase test. The analysed strains from the same cows in each year expressed also nuc and coa genes. About 25% of the strains were examined by the disc diffusion method for their sensitivity to antibiotics. During three years, the strains were highly susceptible in vitro to amoxicillin with clavulanic acid, oxacillin, bacitracin, and cefoperazone (more than 90%), and highly resistant to tetracycline, neomycin, and streptomycin. Forty randomly chosen strains, and eight strains from the same cows in each year were analysed for minimal inhibitory concentration of penicillin G using microdilution method. An increasing resistance to the penicillin was noted. Moreover, eight strains, the same in each year, were also examined for β-lactamase production and methicillin resistance. No β-lactamase producers and no methicillin resistant strains were found using phenotypic and genotypic methods. In conclusion, it can be stated that antimicrobial susceptibility can change from one year to another.

scholarly journals Introduction of the mec Element (Methicillin Resistance) into Staphylococcus aureus Alters In Vitro Functional Activities of Fibrinogen and Fibronectin Adhesins

1998 ◽  
Vol 42 (3) ◽  
pp. 564-570 ◽  
Author(s):  
Pierre E. Vaudaux ◽  
Vincenza Monzillo ◽  
Patrice Francois ◽  
Daniel P. Lew ◽  
Tim J. Foster ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Methicillin Resistance ◽  
Bacterial Colonization ◽  
Protein A ◽  
Methicillin Resistant ◽  
Functional Activities ◽  
Extracellular Matrix Components ◽  
Resistant Strains ◽  
The Impact

ABSTRACT Some methicillin-resistant strains of Staphylococcus aureus are defective in the production of major surface components such as protein A, clumping factor, or other important adhesins to extracellular matrix components which may play a role in bacterial colonization and infection. To evaluate the impact of methicillin resistance (mec) determinants on bacterial adhesion mediated by fibrinogen or fibronectin adhesins, we compared the in vitro attachment of two genetically distinct susceptible strains (NCTC8325 and Newman) to protein-coated surfaces with that of isogenic methicillin-resistant derivatives. All strains containing an intactmec element in their chromosomes were found to be defective in adhesion to fibrinogen and fibronectin immobilized on polymethylmethacrylate coverslips, regardless of the presence or absence of additional mutations in the femA,femB, or femC gene, known to decrease expression of methicillin resistance in S. aureus. Western ligand affinity blotting or immunoblotting of cell wall-associated adhesins revealed similar contents of fibrinogen- or fibronectin-binding proteins in methicillin-resistant strains compared to those of their methicillin-susceptible counterparts. In contrast to methicillin-resistant strains carrying a mec element in their genomes, methicillin-resistant strains constructed in vitro, by introducing the mecA gene on a plasmid, retained their adhesion phenotypes. In conclusion, the chromosomal insertion of themec element into genetically defined strains of S. aureus impairs the in vitro functional activities of fibrinogen or fibronectin adhesins without altering their production. This effect is unrelated to the activity of the mecA gene.

Staphylococcus aureus strains differ in their in vitro responsiveness to human urokinase: evidence that methicillin-resistant strains are predominately nonresponsive to the growth-enhancing effects of urokinase

1996 ◽  
Vol 42 (10) ◽  
pp. 1024-1031 ◽  
Author(s):  
David A. Hart ◽  
Carol Reno ◽  
Thomas Louie ◽  
Wallace Krulicki
Keyword(s):  
Staphylococcus Aureus ◽  
Methicillin Resistance ◽  
Clinical Isolates ◽  
Growth Enhancement ◽  
Western Canada ◽  
Methicillin Resistant ◽  
Resistant Strains ◽  
The Uk ◽  
Regulation Of Growth

Clinical isolates of Staphylococcus aureus were found to exhibit strain-specific heterogeneity to the growth-enhancing effects of human urokinase (UK), a proteinase with plasminogen activator activity. Nine out of fourteen (64%) methicillin-sensitive strains of S. aureus were responsive to UK in "in vitro" cultures. In contrast, 3/29 (10%) methicillin-resistant strains were responsive to the proteinase. When only strains isolated from western Canada were considered, 6/11 methicillin-sensitive strains and 1/26 methicillin-resistant strains were responsive to UK. The single western Canadian methicillin-resistant strain (strain 456) responsive to UK was one of two isolated from the same patient, indicating that the two strains were phenotypically different. Strain 456, resistant to 32 μg mefhicillin/mL, was responsive to as little as 50 U UK/mL and enhancement of growth was evident by 9 h of incubation at 37 °C. This growth enhancement was specific to UK and not duplicated by equivalent concentrations of other proteins (bovine serum albumin, trypsin, plasminogen). The results presented indicate differences in the frequency of the UK-responsive phenotype between methicillin-sensitive and -resistant S. aureus. These findings indicate that the UK phenotype of S. aureus may have utility in both phenotyping clinical isolates, as well as providing insights into the regulation of growth in this clinically important organism.Key words: Staphylococcus aureus, growth, urokinase, methicillin resistance.

scholarly journals In Vitro Activities of 28 Antimicrobial Agents against Staphylococcus aureus Isolates from Tertiary-Care Hospitals in Korea: a Nationwide Survey

2004 ◽  
Vol 48 (4) ◽  
pp. 1124-1127 ◽  
Author(s):  
Hong Bin Kim ◽  
Hee-Chang Jang ◽  
Hee Jung Nam ◽  
Yeong Seon Lee ◽  
Bong Su Kim ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Agents ◽  
Methicillin Resistance ◽  
Tertiary Care ◽  
Nationwide Survey ◽  
Resistance Rate ◽  
Current Status ◽  
Diffusion Method ◽  
Disk Diffusion Method

ABSTRACT Staphylococcus aureus, one of the most frequently isolated pathogens in both hospitals and the community, has been particularly efficient at developing resistance to antimicrobial agents. As methicillin-resistant S. aureus (MRSA) has prevailed and, furthermore, as S. aureus with reduced susceptibility to vancomycin has emerged, the therapeutic options for the treatment of S. aureus infections have become limited. To update the current status of antibiotic resistance, clinical S. aureus isolates were collected from eight university-affiliated hospitals from June 1999 to January 2001. Susceptibility tests with 28 antibiotics were performed by the disk diffusion method. Among a total of 682 isolates, the methicillin resistance rate was 64% (439 of 682), and most of the MRSA isolates were resistant to multiple classes of antibiotics. Although a constitutive macrolide-lincosamide-streptogramin B resistance phenotype was common, no isolates were resistant to quinupristin-dalfopristin or linezolid. Rifampin, fusidic acid, trimethoprim-sulfamethoxazole, and arbekacin showed superior in vitro activity compared with the other antibiotics against the MRSA isolates. No isolates showed reduced susceptibility to vancomycin.

scholarly journals Synthesis, characterization, and in vitro antimicrobial investigation of novel pyran derivatives based on 8-hydroxyquinoline

2019 ◽  
Vol 8 (1) ◽  
Author(s):  
Mohamed Rbaa ◽  
Abdelhadi Hichar ◽  
Omar Bazdi ◽  
Younes Lakhrissi ◽  
Khadija Ounine ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Magnetic Resonance ◽  
Penicillin G ◽  
Diffusion Method ◽  
Bacterial Strains ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Wide Range

Abstract Background 8-Hydroxyquinoline derivatives are known for their extensive applications in the field of analytical chemistry and separation techniques; their complexes with transition metals also exhibit antibacterial and antifungal activity. Results In the present study, we synthesized a new series of pyranoquinoline derivatives and evaluated their antibacterial activities. The structures of the synthesized compounds were characterized by Fourier transform infrared (FT-IR), hydrogen-1 nuclear magnetic resonance, carbon-13 nuclear magnetic resonance, and elemental analysis. All the prepared compounds were evaluated in vitro as antimicrobial agents against Gram-positive and Gram-negative bacterial strains (Escherichia coli (ATCC35218), Staphylococcus aureus (ATCC29213), Vibrio parahaemolyticus (ATCC17802), and Pseudomonas aeruginosa (ATCC27853)). The screening test was determined by using the standard protocol of disc diffusion method (DDM). Conclusion We have synthesized new pyranic compounds bearing an 8-hydroxyquinoline moiety on their structure. The preliminary screening results showed that all the tested compounds have a remarkable inhibitory effect on the growth of the majority of the tested bacterial strains compared to the standard antibiotic (penicillin G), and the chlorinated compound (Q1) is more active against Gram-positive bacteria than Gram-negative bacteria such as the Staphylococcus aureus strain which is the most sensitive. Gram-positive bacteria are responsible for a wide range of infectious diseases, and rising resistance in this group is causing increasing concern. Thus, this study develops novel heterocyclic compound derivatives of 8-hydroxyquinoline that have demonstrated good antibacterial activity against Gram-positive bacteria. Graphical abstract

EVALUATION OF THE METHOSD FOR DETECTION METHICILLIN-RESISTANT STAPHYLOCOCCUS AUREUS.

2013 ◽  
pp. 25-31
Author(s):  
Thi Kim Chi Nguyen ◽  
Dinh Binh Tran ◽  
Thi Nam Lien Nguyen ◽  
Van Tuan Mai ◽  
Godreuil Sylvain
Keyword(s):  
Staphylococcus Aureus ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Methicillin Resistance ◽  
Meca Gene ◽  
Antibiotic Sensitivity ◽  
Diffusion Method ◽  
Disk Diffusion Method ◽  
Antibiotic Resistant ◽  
Methicillin Resistant ◽  
Resistant Strains

Objective: To evaluate the infections that caused by Methicillin-resistant Staphylococcus aureus and the value of the tests to detect Methicillin-resistant Staphylococcus aureus. Subjects and Methods: Used routine techniques to culture and isolate S.aureus, test the antibiotic sensitivity by Kirby-Bauerr, determination the Methicillin-resistant Staphylococcus aureus by Oxacillin and cefoxitin disc and PCR in identified the mecA gene Staphylococcus aureus. Results: The rate of Staphylococcus aureus isolated is highest which isolated from pus specimens (55.06%). In 267 strains of Staphylococcus aureus isolated in the Department of Microbiology, Hue Central Hospital the Methicillin resistance Staphylococcus aureus was 61.42%. The level of antibiotic resistant strains of Methicillin-resistant Staphylococcus aureus is higher than that in Methicillin-sensitive strains. Conclusion: Cefoxitin 30 microg disk diffusion method to detect Methicillin resistance is effective for determinate Methicillin-resistant Staphylococcus aureus (sensitivity and specificity are all 100.00%). Key words: Staphylococcus aureus Methicillin-resistant.

THE IN VITRO EFFECT OF LYSOSTAPHIN ON CLINICAL ISOLATES OF STAPHYLOCOCCUS AUREUS

1964 ◽  
Vol 10 (6) ◽  
pp. 823-828 ◽  
Author(s):  
C. Bruce Cropp ◽  
Edward F. Harrison
Keyword(s):  
Staphylococcus Aureus ◽  
Clinical Isolate ◽  
Clinical Isolates ◽  
Penicillin G ◽  
Aureus Strain ◽  
In Vitro Susceptibility ◽  
Clinical Strains ◽  
Resistant Strains ◽  
Vitro Effect

Lysostaphin, an antibiotic that is unique inasmuch as it lyses all strains of Staphylococcus aureus, has been tested against 252 strains obtained from clinical sources. The clinical isolates were phage typed and tested for in vitro susceptibility to lysostaphin and seven other antistaphylococcal antibiotics.The resistant strains, found generally in phage groups I, III, and Insensitive, were most susceptible to vancomycin, lysostaphin, ristocetin, and kanamycin. The antibiotics least effective were penicillin G, tetracycline, phenethicillin, and erythromycin. As an attempt to quantitate the susceptibility of various clinical strains of 5.S. aureus to lysostaphin, a "lysostaphin index" was devised in which, by an arbitrary criterion, the susceptibility of a clinical isolate was related to the sensitivity of S. aureus, strain FDA 209P. It was found that all isolates were lysed by lysostaphin.

scholarly journals Prevalence of Methicillin-Resistant Staphylococcus aureus Isolated from Clinical Samples at Narayani Samudayik Hospital, Chitwan, Nepal

2020 ◽  
Vol 7 ◽  
pp. 37-42
Author(s):  
Rama Adhikari ◽  
Bindu Kshetri ◽  
Khem Narayan Sharma ◽  
Santosh Khanal ◽  
Om Prakash Panta ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Antibiotic Susceptibility ◽  
Methicillin Resistance ◽  
Diffusion Method ◽  
Clinical Samples ◽  
Susceptibility Pattern ◽  
Cross Sectional ◽  
Mannitol Salt Agar ◽  
Antibiotic Susceptibility Pattern ◽  
Clinical Specimens

Objectives: The main objective of this study was to determine the prevalence of Methicillin Resistance Staphylococcus aureus (MRSA) and MDR bacteria isolated from various clinical specimens from the patients attending Narayani Samudayik Hospital, Chitwan Methods: A cross sectional study was carried in NPI-Narayani Samudayik Hospital, Chitwan from June to December 2017. Altogether, 3610 clinical specimens mainly pus, blood and urine were collected, streaked on Mannitol Salt Agar and Blood Agar and incubated at 37°C for 24 hours. The confirmed colonies of S. aureus were sub-cultured on Nutrient Agar. The antibiotic susceptibility pattern of all isolates S. aureus was determined by Kirby Bauer disc diffusion method. Isolates resistant to cefoxitin (30mcg) were confirmed as MRSA. Result: Among 3610 total clinical samples, 17.6 % (635/3610) showed growth and 95(14.96%) S. aureus were isolated. Higher number of S. aureus was isolated from pus sample (93.15%). Out of 95 S. aureus isolates, 55 (57.89%) were identified as MRSA while 40 (42.10%) were MSSA. Vancomycin, ceftriaxone and chloramphenicol were found to be most effective antibiotic against isolates. Whereas, the least effective antibiotic was cefoxitin followed by amoxiclav, oxacillin and amoxicillin. Conclusion: This study concludes that the overall prevalence of MRSA and MDR among the bacterial isolates is higher compared to other studies. So, it is recommended to monitor the antibiotic susceptibility pattern of pathogens regularly and study the epidemiology of such isolates.  

Formulation and Evaluation of Mefloquine Hydrochloride Nanoparticles

2014 ◽  
Vol 7 (1) ◽  
pp. 2377-2386
Author(s):  
Dilip Kumar Gupta ◽  
B K Razdan ◽  
Meenakshi Bajpai
Keyword(s):  
Particle Size ◽  
Sustained Release ◽  
In Vitro Release ◽  
Entrapment Efficiency ◽  
Taste Masking ◽  
Diffusion Method ◽  
Drug Entrapment Efficiency ◽  
Resistant Strains ◽  
Vitro Release

The present study deals with the formulation and evaluation of mefloquine hydrochloride nanoparticles. Mefloquine is a blood schizonticidal quinoline compound, which is indicated for the treatment of mild-to-moderate acute malarial infections caused by mefloquine-susceptible multi-resistant strains of P. falciparum and P. vivax. The purpose of the present work is to minimize the dosing frequency, taste masking toxicity and to improve the therapeutic efficacy by formulating mefloquine HCl nanoparticles. Mefloquine nanoparticles were formulated by emulsion diffusion method using polymer poly(ε-caprolactone) with six different formulations. Nanoparticles were characterized by determining its particle size, polydispersity index, drug entrapment efficiency, drug content, particle morphological character and drug release. The particle size ranged between 100 nm to 240 nm. Drug entrapment efficacy was >95%. The in-vitro release of nanoparticles were carried out which exhibited a sustained release of mefloquine HCl from nanoparticles up to 24 hrs. The results showed that nanoparticles can be a promising drug delivery system for sustained release of mefloquine HCl.

scholarly journals In Vitro Antibacterial Effect of the Methanolic Extract of the Korean Soybean Fermented Product Doenjang against Staphylococcus aureus

Animals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 2319
Author(s):  
Klara Lalouckova ◽  
Lucie Mala ◽  
Petr Marsik ◽  
Eva Skrivanova
Keyword(s):  
Staphylococcus Aureus ◽  
High Performance ◽  
Methanolic Extract ◽  
Bioactive Substances ◽  
Microdilution Method ◽  
Antibacterial Compound ◽  
Fermented Product ◽  
Broth Microdilution Method

Ultra-high performance liquid chromatography/mass spectrometry showed soyasaponin I and the isoflavones daidzein, genistein, and glycitein to be the main components of the methanolic extract of the Korean soybean fermented product doenjang, which is known to be a rich source of naturally occurring bioactive substances, at average contents of 515.40, 236.30, 131.23, and 29.00 ng/mg, respectively. The antimicrobial activity of the methanolic extract of doenjang against nine Staphylococcusaureus strains was determined in vitro by the broth microdilution method to investigate its potential to serve as an alternative antibacterial compound. The results suggest that the extract is an effective antistaphylococcal agent at concentrations of 2048–4096 µg/mL. Moreover, the tested extract also showed the ability to inhibit the growth of both methicillin-sensitive and methicillin-resistant animal and clinical S. aureus isolates. The growth kinetics of the chosen strains of S. aureus at the minimum inhibitory concentration of the methanolic extract of doenjang support the idea that the tested extract acts as an antibacterial compound. To the best of our knowledge, this is the first report on the antistaphylococcal action of the methanolic extract of doenjang thus, additional studies including in vivo testing are necessary to confirm this hypothesis.

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