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MIC90 Values (mic90 + value)

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Medical Sciences100%

Selected Abstracts

Bacteriology and antimicrobial susceptibility of gram-positive cocci isolated from pus specimens of orofacial odontogenic infections

MOLECULAR ORAL MICROBIOLOGY, Issue 2 2002
T. Kuriyama
We recently reported the ,-lactamase production and antimicrobial susceptibility of anaerobic gram-negative rods isolated from pus specimens of 93 orofacial odontogenic infections. In this report, we determine the bacteriology and antimicrobial susceptibility of bacteria other than anaerobic gram-negative rods, mainly gram-positive cocci, isolated from the same specimens. Streptococcus constellatus and Peptostreptococcus micros were frequent isolates from all types of infection examined. Peptostreptococcus prevotii, Corynebacterium species, and Eubacterium species were recovered only from dentoalveolar infections, while Gemella morbillorum was found more frequently in periodontitis than in the other infections. ,-Lactamase-positive strains were detected only in staphylococci. Ampicillin, ampicillin/sulbactam, cefazolin, cefotaxime, imipenem, erythromycin, clindamycin and levofloxacin showed high susceptibility rates (,77%) against viridans streptococci, Peptostreptococcus and Gemella. Minocycline showed a high MIC90 value against viridans streptococci (32 µg/ml), and metronidazole was effective against Peptostreptococcus and Gemella. These results provide useful information for the treatment of orofacial odontogenic infections. [source]

Pharmacokinetics and tissue distribution of intravenous pefloxacin for antibiotic prophylaxis in biliary surgery

BIOPHARMACEUTICS AND DRUG DISPOSITION, Issue 7 2002
A.R. Gascón
Abstract The plasma levels and tissue penetration of pefloxacin were studied after prophylactic administration to patients undergoing elective biliary surgery. Pefloxacin was administered as a single dose of 800 mg given intravenously as an infusion 1 h before surgery. Over a period of two years, cultures of bile and stone were performed after cholecystectomy in order to find the main pathogens present in the geographical area of the hospital of Txagorritxu (Vitoria, Spain), as well as to test the antimicrobial susceptibility of these bacteria to pefloxacin. Thirty seven per cent of the bile and stone cultures were positive, and 75 different species were isolated. E. coli was the predominant microorganism (25%). Other frequent microorganisms were E. faecium (9.3%), S. epidermidis (6.6%) and Cl. perfringens (6.6%). Most species isolated were susceptible to pefloxacin, with MIC90 values of 0.125 ,g/ml for E. coli, 0.5 ,g/ml for S. epidermidis and 1 ,g/ml for Cl. perfringens. E. faecium was resistant, with a MIC90 value of 8 ,g/ml but a MIC50 of 4 ,g/ml (intermediate). After pefloxacin infusion, adequate drug plasma levels (>MIC90) for the most frequent pathogens were found throughout the procedure. Elimination half-life was estimated as 22.03±6.91 h; the area under the concentration,time curve from zero to infinite had a value of 275.07±130.02 mg h/l and the values for volume of distribution at steady-state and plasma clearance were 96.48±28.65 L and 3.60±1.83 l/h, respectively. Bile pefloxacin concentrations generally exceeded the minimum inhibitory concentrations for most relevant pathogens. Drug levels in gallbladder and subcutaneous tissues were also above the MIC90 for extended periods. Patients were observed daily throughout their hospital stay. This included examination of the surgical wound and recording of body temperature. No cases of anaerobic infection were noted in the study patients. Other constants such as hospitalization stay and time of recuperation were normal for this type of surgery. According to these results, pefloxacin presents many features that make it suitable for use as a therapeutic prophylactic agent, such as its broad spectrum of antimicrobial activity and favorable pharmacokinetic properties. Copyright © 2002 John Wiley & Sons, Ltd. [source]

Antimicrobial profiles of periodontal pathogens isolated from periodontitis patients in the Netherlands and Spain

JOURNAL OF CLINICAL PERIODONTOLOGY, Issue 8 2005
A. J. Van Winkelhoff
Abstract Background and Aim: Antimicrobial resistance of periodontal pathogens towards currently used antibiotics in periodontics has been investigated in a previous study. Microbial resistance in the periodontal microflora was more frequently observed in Spanish patients in comparison with Dutch patients. The aim of the present study was to compare antimicrobial susceptibility profiles of five periodontal bacteria isolated from periodontitis patients in Spain and in the Netherlands. Material and Methods: Subgingival plaque samples from adult patients with periodontitis were collected and cultured on selective and non-selective plates. Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Fusobacterium nucleatum and Micromonas micros were isolated and used for minimal inhibitory concentration tests using the Epsilometer (E-test) technique. Eight different antibiotics were tested on all bacterial isolates. MIC50 and MIC90 values for each antibiotic and each species were determined and the percentage of resistant strains was calculated. Results: Significantly higher MIC values were noted in Spanish strains of F. nucleatum for penicillin, ciprofloxacin, of P. intermedia for penicillin, amoxicillin and tetracycline, of M. micros for tetracycline, amoxicillin and azithromycin, and of P. gingivalis for tetracycline and ciprofloxacin. Based on breakpoint concentrations, a higher number of resistant strains in Spain were found in F. nucleatum for penicillin, amoxicillin and metronidazole, in Prevotella intermedia for tetracycline and amoxicillin, and in A. actinomycetemcomitans for amoxicillin and azithromycin. Resistance of P. gingivalis strains was not observed for any of the antibiotics tested both in Spain and the Netherlands. Conclusions: Differences exist in the susceptibility profiles of periodontal pathogens isolated from periodontitis patients in Spain and in the Netherlands. This implicates that antibiotic susceptibility testing is necessary to determine efficacy of antimicrobial agents. Also, clinical studies with antibiotics should take these differences into account. The information from the present study indicates that it may not be possible to develop uniform protocols for usage of antibiotics in the treatment of severe periodontitis in the European Union. [source]

Pharmacokinetics and tissue distribution of intravenous pefloxacin for antibiotic prophylaxis in biliary surgery

BIOPHARMACEUTICS AND DRUG DISPOSITION, Issue 7 2002
A.R. Gascón
Abstract The plasma levels and tissue penetration of pefloxacin were studied after prophylactic administration to patients undergoing elective biliary surgery. Pefloxacin was administered as a single dose of 800 mg given intravenously as an infusion 1 h before surgery. Over a period of two years, cultures of bile and stone were performed after cholecystectomy in order to find the main pathogens present in the geographical area of the hospital of Txagorritxu (Vitoria, Spain), as well as to test the antimicrobial susceptibility of these bacteria to pefloxacin. Thirty seven per cent of the bile and stone cultures were positive, and 75 different species were isolated. E. coli was the predominant microorganism (25%). Other frequent microorganisms were E. faecium (9.3%), S. epidermidis (6.6%) and Cl. perfringens (6.6%). Most species isolated were susceptible to pefloxacin, with MIC90 values of 0.125 ,g/ml for E. coli, 0.5 ,g/ml for S. epidermidis and 1 ,g/ml for Cl. perfringens. E. faecium was resistant, with a MIC90 value of 8 ,g/ml but a MIC50 of 4 ,g/ml (intermediate). After pefloxacin infusion, adequate drug plasma levels (>MIC90) for the most frequent pathogens were found throughout the procedure. Elimination half-life was estimated as 22.03±6.91 h; the area under the concentration,time curve from zero to infinite had a value of 275.07±130.02 mg h/l and the values for volume of distribution at steady-state and plasma clearance were 96.48±28.65 L and 3.60±1.83 l/h, respectively. Bile pefloxacin concentrations generally exceeded the minimum inhibitory concentrations for most relevant pathogens. Drug levels in gallbladder and subcutaneous tissues were also above the MIC90 for extended periods. Patients were observed daily throughout their hospital stay. This included examination of the surgical wound and recording of body temperature. No cases of anaerobic infection were noted in the study patients. Other constants such as hospitalization stay and time of recuperation were normal for this type of surgery. According to these results, pefloxacin presents many features that make it suitable for use as a therapeutic prophylactic agent, such as its broad spectrum of antimicrobial activity and favorable pharmacokinetic properties. Copyright © 2002 John Wiley & Sons, Ltd. [source]

In vitro susceptibility to 17 antimicrobials of clinical Clostridium difficile isolates collected in 1993,2007 in Sweden

CLINICAL MICROBIOLOGY AND INFECTION, Issue 8 2010
T. Norén
Clin Microbiol Infect 2010; 16: 1104,1110 Abstract This study investigated the MICs of 17 antimicrobials, for 606 toxigenic clinical isolates of Clostridium difficile collected between 1993 and 2007 in Sweden. Low MIC90 values were found for metronidazole (0.5 mg/L), vancomycin (1.0 mg/L), teicoplanin (0.125 mg/L), fusidic acid (1.0 mg/L), linezolid (2.0 mg/L), daptomycin (2.0 mg/L) and tigecycline (0.064 mg/L). Three isolates (0.5%) had elevated MICs for vancomycin (4,8 mg/L); however, these isolates originated from the same patient, who was receiving long-term intravenous vancomycin treatment. High-level clindamycin resistant isolates (MIC >256 mg/L) peaked in 1997 with 39 of 95 (41%) and out of these, 36% were also highly resistant to erythromycin. ,-Lactams such as penicillin V and piperacillin displayed MIC90s of 8 and 32 mg/L, respectively, whereas MICs of cefuroxime were >256 mg/L for all isolates. Universal resistance to ciprofloxacin and levofloxacin was found, and resistance to moxifloxacin increased from 4% of isolates in 2004 to 23% in 2007. Notably, these moxifloxacin-resistant isolates did not belong to the recent epidemic PCR ribotype 027, but to the pre-existing epidemic type 012 (82%), and these isolates accounted for the majority of isolates that were resistant to clindamycin (70%), tetracycline (84%) and rifampicin (92%) as well. This investigation of susceptibility data on clinical C. difficile isolates showed variations of multiresistance to be due to a specific PCR ribotype 012, emphasizing the importance of genotyping when evaluating emerging resistance over time. [source]