scholarly journals Phenolic Plant Extracts Versus Penicillin G: In Vitro Susceptibility of Staphylococcus aureus Isolated from Bovine Mastitis

2019 ◽  
Vol 12 (3) ◽  
pp. 128
Author(s):  
Fernanda Gomes ◽  
Maria Rodrigues ◽  
Natália Martins ◽  
Isabel Ferreira ◽  
Mariana Henriques
Keyword(s):  
Staphylococcus Aureus ◽  
Plant Extracts ◽  
Antimicrobial Agents ◽  
Juglans Regia ◽  
Bovine Mastitis ◽  
Treatment Plant ◽  
The Other ◽  
Penicillin G ◽  
In Vitro Susceptibility

Antibiotics are the elective drugs in bovine mastitis (BM) treatment, despite their low rates of efficiency and effectiveness and increasing risk of pathogen resistance. In this sense, it is urgent to discover new and effective antimicrobial agents to apply in BM control and even treatment. Plant extracts have been widely recognized as a rich source of phytochemicals with antimicrobial potential. Thus, the present work aims to compare the bioactivity of Eucalyptus globulus and Juglans regia extracts against Staphylococcus aureus bovine mastitis strains with penicillin G. At non-toxic concentrations, E. globulus exerted a bacteriostatic effect in planktonic cells and J. regia had no antimicrobial activity. Penicillin G, at minimum inhibitory concentration (MIC), demonstrated bactericidal activity, but just for S. aureus 3, 5, 6 and ATCC 25923, while the other strains seem to have acquired resistance. On the other hand, E. globulus and penicillin G in combination demonstrated synergy, being the most effective approach against S. aureus 1, 2 and 4. Thus, penicillin alone and in combination with E. globulus or J. regia seems to be promissory strategies to control bovine mastitis infections.

scholarly journals Temporal profile of antimicrobial resistance exhibited by strains of Staphylococcus spp. isolated from cases of bovine mastitis for 20 years (1992-2011)

2015 ◽  
Vol 45 (6) ◽  
pp. 1035-1041
Author(s):  
Ananda Paula Kowalski ◽  
Grazieli Maboni ◽  
Julia Pires Espindola ◽  
Ariane Foletto ◽  
Guerino Bandeira Junior ◽  
...  
Keyword(s):  
Regression Analysis ◽  
Antimicrobial Resistance ◽  
Bovine Mastitis ◽  
The Other ◽  
In Vitro Susceptibility ◽  
Resistance Patterns ◽  
Susceptibility Tests ◽  
Resistance Rates ◽  
Staphylococcus Spp

Records of in vitro susceptibility tests performed between 1992 and 2011 were retrospectively reviewed in order to evaluate the dynamic profiles of possible changes in antimicrobial resistance of Staphylococcus spp. isolated from milk samples of cows with mastitis during two decades. The results of 2,430 isolates tested by disk diffusion technique for susceptibility to oxacillin, penicillin, ampicillin, cephalexin, norfloxacin, tetracycline, sulfazotrim, gentamicin, and neomycin were analysed. Comparisons were performed between the percentages of resistance to antimicrobials and their classes and also between the decades studied. Additionally, the possible tendency or changes in the behaviour of these pathogens against the major drugs used in the last two decades were evaluated using regression analysis. The highest rates of resistance (P<0.0001) were observed for the beta-lactams (34.3%), with exception of cephalexin (6.9%), and for the tetracyclines (28%). Similar resistance rates (7.6% to 15.7%) were observed among the other drugs. Regression analysis showed a reduction in resistance to penicillin and ampicillin throughout the period, whilst for oxacillin and neomycin a decrease in the resistance was observed during the first decade, followed by an increase. A trend towards decreased resistance was found for sulfazotrim, whereas for the other antimicrobials no decrease was observed. The results indicated no trend towards increased resistance for most antimicrobials tested. Nevertheless, it is necessary to monitor the resistance patterns of these pathogens in order to save these drugs as a therapeutic reserve

Increase in the in vitro susceptibility of Staphylococcus aureus to antimicrobial agents in the presence of Candida albicans

1979 ◽  
Vol 25 (4) ◽  
pp. 429-435 ◽  
Author(s):  
J. deRepentigny ◽  
R. Lévesque ◽  
L. G. Mathieu
Keyword(s):  
Staphylococcus Aureus ◽  
Cell Wall ◽  
Candida Albicans ◽  
Inhibitory Activity ◽  
Antimicrobial Agents ◽  
Mixed Cultures ◽  
Alpha Toxin ◽  
In Vitro Susceptibility ◽  
Pure Cultures

In experiments with mixed cultures of Staphylococcus aureus and Candida albicans both in the absence and in the presence of 5-fluorocytosine (5-FC), we have observed that (1) there is an inhibition of S. aureus growth in mixed cultures with C. albicans in media supplemented with 1 μg/mL of 5-FC and that 5-FC has no effect on staphylococci in pure cultures; (2) this inhibition occurred with clinically isolated and laboratory strains and could be reversed by specific metabolites; (3) Staphylococcus aureus was inhibited by filtrates of C. albicans cultures treated with 5-FC and this seemed to be favored by some C. albicans filterable product which can affect the cell wall and the permeability of the staphylococcal cells since they become sensitive to 5-FC; (4) nine other commonly used antimicrobials showed an increased inhibitory activity against S. aureus in mixed cultures with C. albicans; and (5) there is a decrease in the number of precipitating antigens of S. aureus and of the activity of alpha toxin when this species was grown with both C. albicans and 5-FC. Our results indicate that the susceptibility of some species to antimicrobials could be significantly modified in the presence of other species. One cannot exclude that a similar phenomenon could happen in hosts under treatment with antibiotics against infection.

Activity of Nadifloxacin against Methicillin-Resistant Staphylococcus aureus Isolated from Skin Infections: Comparative Study with Seven other Fluoroquinolones

1996 ◽  
Vol 24 (1) ◽  
pp. 12-16 ◽  
Author(s):  
S Nishijima ◽  
M Nakagawa ◽  
N Tsuboi ◽  
H Akamatsu ◽  
T Horio ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Minimum Inhibitory Concentration ◽  
Comparative Study ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Inhibitory Concentration ◽  
The Other ◽  
Skin Infections ◽  
In Vitro Susceptibility ◽  
Methicillin Resistant

The in vitro susceptibility of methicillin-resistant Staphylococcus aureus(MRSA) to nadifloxacin and seven other fluoroquinolones (norfloxacin, ofloxacin, enoxacin, ciprofloxacin, lomefloxacin, tosufloxacin and sparfloxacin) was evaluated. The MRSA isolates were isolated from 114 skin infections between 1991 and 1994. Nadifloxacin exhibited the lowest minimum inhibitory concentration and there were no MRSA isolates resistant to nadifloxacin, while there were some resistant to all of the other seven fluoroquinolones. The minimum concentrations of these drugs needed to cause 50% inhibition of the isolates increased dramatically from 1991 to 1992, but has hardly changed since 1992.

scholarly journals In Vitro Susceptibility of Borrelia spielmanii to Antimicrobial Agents Commonly Used for Treatment of Lyme Disease

2008 ◽  
Vol 53 (3) ◽  
pp. 1281-1284 ◽  
Author(s):  
Kristina Morgenstern ◽  
Georg Baljer ◽  
Douglas E. Norris ◽  
Peter Kraiczy ◽  
Christa Hanssen-Hübner ◽  
...  
Keyword(s):  
Lyme Disease ◽  
Antimicrobial Agents ◽  
The Other ◽  
Susceptibility Pattern ◽  
In Vitro Susceptibility ◽  
Antibiotic Agents

ABSTRACT Ten isolates of the recently delineated genospecies Borrelia spielmanii were tested against antimicrobial agents used to treat Lyme disease and compared to eight isolates of the other three human-pathogenic borrelial genospecies. Despite some small but significant differences in four out of eight antibiotic agents, the susceptibility pattern of B. spielmanii mainly parallels that of the other known human-pathogenic members of the B. burgdorferi sensu lato complex.

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.

Sensitivity of Staphylococcus Aureus, Isolated from Skin Infections in 1994, to 19 Antimicrobial Agents

1995 ◽  
Vol 23 (5) ◽  
pp. 328-334 ◽  
Author(s):  
S Nishijima ◽  
M Nakagawa ◽  
T Sugiyama ◽  
H Akamatsu ◽  
T Horio ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Fusidic Acid ◽  
Antimicrobial Agents ◽  
Skin Infections ◽  
In Vitro Susceptibility ◽  
Methicillin Resistant ◽  
Cefpodoxime Proxetil ◽  
Agar Dilution ◽  
Resistant Strains

The most common pathogen causing skin infections is Staphylococcus aureus and the incidence of multiply resistant strains of S. aureus has been increasing. The in vitro susceptibility of 130 isolates of S. aureus to 19 antimicrobial agents: ampicillin (ABPC), methicillin, cefaclor, cefpodoxime proxetil, gentamicin, erythromycin, clindamycin, minocycline, vancomycin, fusidic acid, norfloxacin, ofloxacin, enoxacin, ciprofloxacin, lomefloxacin, tosufloxacin, sparfloxacin, nadifloxacin and grepafloxacin, was evaluated by agar dilution tests. The S. aureus isolates were isolated from 130 patients with skin infections in 1994. The proportion of methicillin-resistant S. aureus isolates among the strains isolated was 19.2%. The concentration needed to inhibit 50% of the isolates was 3.13 mg/ml or less for all of the drugs, but the concentration needed to inhibit 90% of isolates was over 12.5 μg/ml, except in the cases of minocycline, vancomycin, fusidic acid, tosufloxacin and nadifloxacin. Tosufloxacin and nadifloxacin had the lowest minimum inhibitory concentrations. None of the S. aureus strains was resistant to nadifloxacin.

scholarly journals Microbiological and molecular aspects of Staphylococcus aureus isolated from bovine mastitis in West-Central Brazil

2020 ◽  
Vol 14 (1) ◽  
pp. 87
Author(s):  
T. B. Vieira ◽  
R. Almeida ◽  
I. B. Jesus ◽  
F. Freitas ◽  
R. T. Kemper ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Agents ◽  
Bovine Mastitis ◽  
Subclinical Mastitis ◽  
Enterotoxin Gene ◽  
Central Brazil ◽  
Lactating Cows ◽  
Molecular Aspects ◽  
And Staphylococcus Aureus

Bovine mastitis is a major disease affecting dairy cattle, and Staphylococcus aureus is one of the most important agent involved in this condition due to its capacity to produce enterotoxins and develop resistance to antimicrobial agents. This study aimed to detect S. aureus strains in milk samples from cows with subclinical mastitis employing microbiological and molecular analysis.  Eleven farms were visited and from 187 lactating cows sampled, 33 S. aureus strains were isolated.  Only one of the 33 strains was positive for mecA resistance gene, 23 were positive for sea enterotoxin gene, and none was positive for seb or sec enterotoxin gene. S. aureus strains were submitted to in vitro antimicrobial susceptibility test and 63.6% (21/33) were susceptible to all antimicrobials tested, while 36.3% (12/33) were resistant to one or more antimicrobial agents. Identification of mecA and the sea genes highlighted the need to elaborate strategies to reduce problems related to animal. Furthermore, the identification of bovine mastitis caused by S. aureus is very important to manage herd and to public health, since milk contaminated by this pathogen can lead to serious health problems.

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