scholarly journals Antimicrobial Susceptibilities of Multidrug-Resistant Campylobacter jejuni and C. coli Strains: In Vitro Activities of 20 Antimicrobial Agents

2009 ◽  
Vol 54 (3) ◽  
pp. 1232-1236 ◽  
Author(s):  
Mirva Lehtopolku ◽  
Ulla-Maija Nakari ◽  
Pirkko Kotilainen ◽  
Pentti Huovinen ◽  
Anja Siitonen ◽  
...  
Keyword(s):  
Campylobacter Jejuni ◽  
Antimicrobial Agents ◽  
Agar Plate ◽  
Inhibition Zone ◽  
Multidrug Resistant ◽  
Dilution Method ◽  
Erythromycin Resistance ◽  
Disk Diffusion Test ◽  
Resistant Strains

ABSTRACT There is a paucity of information regarding antimicrobial agents that are suitable to treat severe infections caused by multidrug-resistant Campylobacter spp. Our aim was to identify agents that are potentially effective against multiresistant Campylobacter strains. The in vitro activities of 20 antimicrobial agents against 238 Campylobacter strains were analyzed by determining MICs by the agar plate dilution method or the Etest. These strains were selected from 1,808 Campylobacter isolates collected from Finnish patients between 2003 and 2005 and screened for macrolide susceptibility by using the disk diffusion test. The 238 strains consisted of 183 strains with erythromycin inhibition zone diameters of ≤23 mm and 55 strains with inhibition zone diameters of >23 mm. Of the 238 Campylobacter strains, 19 were resistant to erythromycin by MIC determinations (MIC ≥ 16 μg/ml). Given that the resistant strains were identified among the collection of 1,808 isolates, the frequency of erythromycin resistance was 1.1%. All erythromycin-resistant strains were multidrug resistant, with 18 (94.7%) of them being resistant to ciprofloxacin (MIC ≥ 4 μg/ml). The percentages of resistance to tetracycline and amoxicillin-clavulanic acid (co-amoxiclav) were 73.7% and 31.6%, respectively. All macrolide-resistant strains were susceptible to imipenem, meropenem, and tigecycline. Ten (52.6%) multiresistant strains were identified as being Campylobacter jejuni strains, and 9 (47.4%) were identified as being C. coli strains. These data demonstrate that the incidence of macrolide resistance was low but that the macrolide-resistant Campylobacter strains were uniformly multidrug resistant. In addition to the carbapenems, tigecycline was also highly effective against these multidrug-resistant Campylobacter strains in vitro. Its efficacy for the treatment of human campylobacteriosis should be evaluated in clinical trials.

scholarly journals In Vitro Activities of New Fluoroquinolones against Campylobacter jejuni and Campylobacter coli Isolates Obtained from Humans in 1980 to 1982 and 1997 to 2001

2003 ◽  
Vol 47 (9) ◽  
pp. 2946-2950 ◽  
Author(s):  
Rea Krausse ◽  
Uwe Ullmann
Keyword(s):  
Campylobacter Jejuni ◽  
Antibacterial Agents ◽  
Antimicrobial Agents ◽  
Agar Plate ◽  
Antibacterial Activities ◽  
Fluoroquinolone Resistance ◽  
Cross Resistance ◽  
Dilution Method ◽  
Campylobacter Coli

ABSTRACT The antibacterial activities of three newly developed fluoroquinolones (gatifloxacin, levofloxacin, and moxifloxacin) against a total of 307 gastrointestinal human isolates of Campylobacter jejuni and Campylobacter coli collected during 1980 to 1982 and 1997 to 2001 were examined and compared to those of ciprofloxacin and the unrelated antibacterial agents, clarithromycin, erythromycin, and tetracycline by using the agar plate dilution method. All of the fluoroquinolones exhibited a good activity against Campylobacter, and some of them were more active than ciprofloxacin, the macrolides, and tetracycline. Among the fluoroquinolones, gatifloxacin and moxifloxacin showed the highest anticampylobacter activity, with MICs at which 50% of the isolates tested are inhibited (MIC50s) and MIC90s of 0.125 and 4 μg/ml, respectively; the MIC50 for both levofloxacin and ciprofloxacin was 0.25, and the MIC90s were 16 and 32 μg/ml, respectively. About 30% of the strains were found to be resistant to at least one fluoroquinolone. Resistance to gatifloxacin occurred in 9.8% of the isolates tested, and resistance to the other fluoroquinolones occurred in 19.9 to 27.4% of the isolates tested; the frequency of cross-resistance was 35.7 to 100%. An increase in fluoroquinolone resistance from 0% in 1980 to 1982 to 11.8 to 29% in 1997 and 1998, 8.2 to 31.8% in 1999 and 2000, and 12.1 to 30.3% in 2001 was found. A total of 61.4 to 73.2% of the C. jenuni strains resistant to erythromycin, clarithromycin, and/or tetracycline were susceptible to fluoroquinolones; gatifloxacin showed the highest percentage of inhibition. These results show that the newer fluoroquinolones with their potent activity could be used to treat infections with C. jejuni and C. coli. However, when these drugs are used, one must consider the increase in resistance and the high cross-resistance to these antimicrobial agents.

scholarly journals In Vitro Activities of β-Lactam–β-Lactamase Inhibitor Antimicrobial Agents against Cystic Fibrosis Respiratory Pathogens

2019 ◽  
Vol 64 (1) ◽  
Author(s):  
Lindsay J. Caverly ◽  
Theodore Spilker ◽  
Linda M. Kalikin ◽  
Terri Stillwell ◽  
Carol Young ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Antimicrobial Agents ◽  
Multidrug Resistant ◽  
Respiratory Pathogens ◽  
Content Type ◽  
Resistant Strains ◽  
Drug Resistant Strains ◽  
Increased Activity ◽  
Lactamase Inhibitor

ABSTRACT We tested the in vitro activities of ceftazidime-avibactam, ceftolozane-tazobactam, meropenem-vaborbactam, piperacillin-tazobactam, and 11 other antimicrobial agents against 420 Burkholderia, Achromobacter, Stenotrophomonas, and Pandoraea strains, 89% of which were cultured from respiratory specimens from persons with cystic fibrosis. Among the β-lactam–β-lactamase inhibitor agents, meropenem-vaborbactam had the greatest activity against Burkholderia and Achromobacter, including multidrug-resistant and extensively-drug-resistant strains. None of the newer β-lactam–β-lactamase combination drugs showed increased activity compared to that of the older agents against Stenotrophomonas maltophilia or Pandoraea spp.

scholarly journals Antimicrobial Susceptibilities of Campylobacter Strains Isolated from Finnish Subjects Infected Domestically or from Those Infected Abroad

2003 ◽  
Vol 47 (1) ◽  
pp. 102-105 ◽  
Author(s):  
Hilpi Rautelin ◽  
Antti Vierikko ◽  
Marja-Liisa Hänninen ◽  
Martti Vaara
Keyword(s):  
Campylobacter Jejuni ◽  
Antimicrobial Agents ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Campylobacter Coli ◽  
Antimicrobial Susceptibilities ◽  
Agar Dilution ◽  
Stool Samples

ABSTRACT The in vitro susceptibilities of 678 Campylobacter jejuni and Campylobacter coli strains isolated from stool samples of the same number of Finnish subjects were studied. A total of 523 patients, representing inhabitants from throughout Finland, had not traveled abroad within the 2 weeks prior to becoming ill, whereas 155 persons had presumably acquired their infections abroad. The antimicrobial agents studied were erythromycin, ciprofloxacin, levofloxacin, trovafloxacin, and moxifloxacin. The MICs of these antimicrobial agents were determined by the agar dilution method. The growth of all domestic isolates was inhibited by erythromycin at concentrations of 4 μg/ml, and for these isolates the fluoroquinolone MICs at which 90% of isolates are inhibited (MIC90s) ranged from 0.06 to 0.5 μg/ml. For the foreign isolates, the erythromycin MIC90 was still low (4 μg/ml), but their susceptibilities to fluoroquinolones were clearly reduced (MIC90s, 8 to 64 μg/ml). Of the four different fluoroquinolones studied, ciprofloxacin was the least active (MIC90, 64 μg/ml).

scholarly journals Characterization of Two New Multidrug-Resistant Strains of Mycobacterium smegmatis: Tools for Routine In Vitro Screening of Novel Anti-Mycobacterial Agents

Antibiotics ◽  
2019 ◽  
Vol 8 (1) ◽  
pp. 4 ◽  
Author(s):  
Patrick K. Arthur ◽  
Vincent Amarh ◽  
Precious Cramer ◽  
Gloria B. Arkaifie ◽  
Ethel J. S. Blessie ◽  
...  
Keyword(s):  
Mycobacterium Smegmatis ◽  
Antimicrobial Agents ◽  
Multidrug Resistant ◽  
Health Concern ◽  
Model Organisms ◽  
In Vitro Screening ◽  
Global Public Health ◽  
Wide Range ◽  
Resistant Strains

Mycobacterium tuberculosis is a pathogen of global public health concern. This threat is exacerbated by the emergence of multidrug-resistant and extremely-drug-resistant strains of the pathogen. We have obtained two distinct clones of multidrug-resistant Mycobacterium smegmatis after gradual exposure of Mycobacterium smegmatis mc2 155 to increasing concentrations of erythromycin. The resulting resistant strains of Mycobacterium smegmatis exhibited robust viability in the presence of high concentrations of erythromycin and were found to be resistant to a wide range of other antimicrobials. They also displayed a unique growth phenotype in comparison to the parental drug-susceptible Mycobacterium smegmatis mc2 155, and a distinct colony morphology in the presence of cholesterol. We propose that these two multidrug-resistant clones of Mycobacterium smegmatis could be used as model organisms at the inceptive phase of routine in vitro screening of novel antimicrobial agents targeted against multidrug-resistant Mycobacterial tuberculosis.

Antifungi Efficacy of the Compound Preparation of Anemarrhena asphodeloides Bunge on the Drug Resistant Strain of Candida Albicans

2012 ◽  
Vol 518-523 ◽  
pp. 5569-5572 ◽  
Author(s):  
Lian Lan Ma ◽  
Zhi Chun Liu ◽  
Wen Ping Zhang ◽  
Hua Yan Chen ◽  
Xiao Yun Wu
Keyword(s):  
Candida Albicans ◽  
National Laboratory ◽  
Agar Plate ◽  
Inhibition Zone ◽  
The United States ◽  
Standard Strain ◽  
Resistant Strains ◽  
Effective Group ◽  
Anemarrhena Asphodeloides

To investigate the efficacy of the compound preparation named KZY-2 which include the effective group formula of anemarrhena asphodeloides bunge and rhizoma coptidis on the fluconazole and ifraconazo resistant strains of Candida albicans respectively in vitro. The fluconazole and ifraconazo resistant strains of Candida albicans were sieved by drug sensitive scrip test and the diameter of inhibition zone was measured adopting the method of agar plate diffusion, reference to the M27-A recommended by the United States National Laboratory Standards Committee (NCCLS), the minimal inhibitive concentration(MIC,mg/m1) of KZY-2 against the the standard strain(ATCC32354) and the fluconazole and ifraconazo resistant strains of candida albicans was measured respectively. Results showed that the 12 fluconazole and ifraconazo resistant strains which named RC1 to RC12 were sieved from the 20 strains Candida albicans isolated from clinic, the diameters of inhibited zone of KZY-2 against ATCC32354 was 32mm and against RC1～RC12 was between 12mm and 28mm, the MIC of KZY-2 against ATCC32354 was 312.5μg/m1 and against RC1～RC12 was between 625μg /m1 and 5000μg /m1. These results indicate that KZY-2 has good antifungi efficacy on the standard strain and the fluconazole and ifraconazo resistant strains of Candida albicans in vitro.

scholarly journals In vitro efficacy of gentamicin against multidrug-resistant Neisseria gonorrhoeae: synergy of three gentamicin antimicrobial combinations

2021 ◽  
Author(s):  
Xuechun Li ◽  
Wenjing Le ◽  
Xiangdi Lou ◽  
Biwei Wang ◽  
Caroline A. Genco ◽  
...  
Keyword(s):  
Inhibitory Concentration ◽  
Geometric Mean ◽  
Multidrug Resistant ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Fractional Inhibitory Concentration ◽  
Agar Dilution ◽  
Resistant Strains ◽  
Antimicrobial Combinations

ABSTRACTObjectivesTo determine in vitro activities of gentamicin alone and in combination with ceftriaxone, ertapenem and azithromycin against multidrug-resistant (MDR) N. gonorrhoeae isolates.Methods407 isolates from Nanjing, China, obtained in 2016 and 2017, had minimum inhibitory concentrations (MICs) determined for gentamicin using the agar dilution method. Antimicrobial combinations were also tested in 97 MDR strains using the antimicrobial gradient epsilometer test (Etest); results ranging from synergy to antagonism were interpreted using the fractional inhibitory concentration (FICI).ResultsAll 407 gonococcal isolates were susceptible to gentamicin. MICs ranged from 2 mg/L to 16 mg/L. Synergy was demonstrated in 16.5%(16/97), 27.8%(27/97) and 8.2%(8/97) MDR strains when gentamicin was combined with ceftriaxone [geometric mean (GM) FICI; 0.747], ertapenem (GM FICI; 0.662) and azithromycin (GM FICI; 1.021), respectively. No antimicrobial antagonism was observed with any combination. The three antimicrobial combinations were indifferent overall. The overall GM MICs of gentamicin were reduced by 2.63-, 3.80- and 1.98-fold when tested in combination with ceftriaxone, ertapenem and azithromycin, respectively. The GM MICs of the three antimicrobials by themselves were reduced by 3-, 2.57- and 1.98-fold respectively, when each was tested in combination with gentamicin. No antimicrobial antagonism was observed with any combination.ConclusionsGentamicin alone was effective in vitro against MDR N. gonorrhoeae and in combination with ceftriaxone, ertapenem or azithromycin. Combination testing of resistant strains, overall, showed lower effective MICs against gentamicin itself and each of the three antimicrobials when used in combination with gentamicin.

scholarly journals In Vitro Activity of Doripenem (S-4661) against Multidrug-Resistant Gram-Negative Bacilli Isolated from Patients with Cystic Fibrosis

2005 ◽  
Vol 49 (6) ◽  
pp. 2510-2511 ◽  
Author(s):  
Yunhua Chen ◽  
Elizabeth Garber ◽  
Qiuqu Zhao ◽  
Yigong Ge ◽  
Matthew A. Wikler ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Pseudomonas Aeruginosa ◽  
Burkholderia Cepacia ◽  
Antimicrobial Agents ◽  
Multidrug Resistant ◽  
Vitro Activity ◽  
In Vitro Activity ◽  
Gram Negative ◽  
Resistant Strains

ABSTRACT Doripenem 50% inhibitory concentrations (MIC50) and 90% inhibitory concentrations (MIC90) for multidrug-resistant strains of mucoid Pseudomonas aeruginosa (n = 200 strains), nonmucoid P. aeruginosa (n = 200), and Burkholderia cepacia complex (n = 200) isolated from patients with cystic fibrosis were 8 and 32, 8 and 64, and 8 and 32 μg/ml, respectively. Doripenem had somewhat better activity than established antimicrobial agents.

scholarly journals 1280. In-Vitro Activity of Cefiderocol, Imipenem/Relebactam, & Ceftazidime/Avibactam in Ceftolozane/Tazobactam Resistant Strains of Multidrug Resistant Pseudomonas aeruginosa

2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S655-S655
Author(s):  
Daniel Navas ◽  
Angela Charles ◽  
Amy Carr ◽  
Jose Alexander
Keyword(s):  
Multidrug Resistant ◽  
Resistance Mechanisms ◽  
Vitro Activity ◽  
Clinical Isolates ◽  
Resistance Testing ◽  
Clinical Samples ◽  
In Vitro Activity ◽  
Carbapenemase Gene ◽  
Resistant Strains

Abstract Background The activity of imipenem/relebactam (I/R), ceftazidime/avibactam (CZA) and cefiderocol (FDC) were evaluated against clinical isolates of multidrug resistant (MDR) strains of P. aeruginosa which was resistant to ceftolozane/tazobactam (C/T). The recent increase of MDR P. aeruginosa strains isolated from clinical samples has prompted research and development of new antimicrobials that can withstand its multiple resistance mechanisms. C/T is an effective option for treatment of MDR P. aeruginosa in our facility with only 10% of resistance in MDR strains, but the emergence of resistance may occur due to the presence of a carbapenemase gene or an ampC mutation. Methods Antimicrobial susceptibility testing for C/T Etest® (bioMérieux, Inc.) were performed on all MDR strains initially screened by the VITEK2® (bioMérieux, Inc.). 10% (n=20) of all MDR isolates were resistant to C/T by the CLSI 2019 breakpoints. These resistant isolates were tested for presence of a carbapenemase gene using the GeneXpert CARBA-R (Cepheid®) PCR and against CZA Etest® (bioMérieux, Inc.) I/R gradient strips (Liofilchem®) and FDC broth microdilution (Thermo Scientific™ Sensititre™). Results A total of 20 clinical isolates of MDR P. aeruginosa resistant to C/T were tested following standardized CLSI protocols and techniques. All 20 isolates were screened for the presence of a carbapenemase gene (blaVIM, blaNDM, blaKPC, blaOXA-48, blaIMP). A blaVIM gene was detected in 6 (30%) out of 20 isolates. FDC demonstrated the greatest activity with 85% (n=17) of susceptible isolates (CLSI MIC <4µg/dL). CZA (CLSI MIC <8µg/dL) and I/R (FDA MIC <2µg/dL) showed 15% (n=3) and 10% (n=2) of susceptible isolates respectively. FDC was active against all 6 blaVIM isolates, where all 6 strains were resistant to CZA and I/R as expected. 3 isolates tested non-susceptible against FDC; additional characterization was not performed at this time. Conclusion Based on these results, FDC demonstrated the greatest in-vitro activity against C/T resistant strains of MDR P. aeruginosa. FDC also demonstrated activity against all 6 MDR P. aeruginosa carrying blaVIM gene. FDC is a strong option to consider on MDR P. aeruginosa strains based on a resistance testing algorithm and a cost/effective protocol. Disclosures All Authors: No reported disclosures

scholarly journals Silver Nanoparticles and Their Antibacterial Applications

2021 ◽  
Vol 22 (13) ◽  
pp. 7202
Author(s):  
Tamara Bruna ◽  
Francisca Maldonado-Bravo ◽  
Paul Jara ◽  
Nelson Caro
Keyword(s):  
Silver Nanoparticles ◽  
Antibacterial Agents ◽  
Multidrug Resistant ◽  
Secondary Effects ◽  
Cytotoxic Effects ◽  
Factors Affecting ◽  
Gram Positive Bacteria ◽  
Resistant Strains

Silver nanoparticles (AgNPs) have been imposed as an excellent antimicrobial agent being able to combat bacteria in vitro and in vivo causing infections. The antibacterial capacity of AgNPs covers Gram-negative and Gram-positive bacteria, including multidrug resistant strains. AgNPs exhibit multiple and simultaneous mechanisms of action and in combination with antibacterial agents as organic compounds or antibiotics it has shown synergistic effect against pathogens bacteria such as Escherichia coli and Staphylococcus aureus. The characteristics of silver nanoparticles make them suitable for their application in medical and healthcare products where they may treat infections or prevent them efficiently. With the urgent need for new efficient antibacterial agents, this review aims to establish factors affecting antibacterial and cytotoxic effects of silver nanoparticles, as well as to expose the advantages of using AgNPs as new antibacterial agents in combination with antibiotic, which will reduce the dosage needed and prevent secondary effects associated to both.

Sign in / Sign up

Export Citation Format

Share Document