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At least 919 records · Page 51Linked to original sources
PubMed1997

Resistance to ciprofloxacin in pathogenic Enterobacteriaceae in England and Wales in 1996.

In 1996, 6% of Escherichia coli from extraintestinal infections were resistant to ciprofloxacin with minimum inhibitory concentrations (MICs) > or = 2 mg/l (high level resistance). Low level resistance (MIC 0.125-1 mg/l) was also identified in 7% of Salmonella typhi, 4% of S paratyphi A, and 4% of non-typhoidal salmonellas. However, resistance to ciprofloxacin was rarely identified in shigellas. For E coli, physicians should be aware that treatment failures may occur when patients with invasive illness are treated with ciprofloxacin before the results of laboratory sensitivity tests are available. For salmonellas an increasing number of treatment failures have been recorded for patients infected with strains with low level resistance. Because of the increasing incidence of Enterobacteriaceae with low level resistance to ciprofloxacin, it is recommended that for this group of organisms a breakpoint of 0.125 mg/l should be included in laboratory sensitivity tests.

Anti-Infective Agents↗
PubMed2000

Synthesis and antimicrobial activity of 1-aryl-2-amino-3-(4-arylthiazol-2-yl)/(benzothiazol-2-yl)guanidines.

The synthesis of fifteen new 1-aryl-2-amino-3-(4-arylthiazol-2-yl)/(benzothiazol-2-yl)gua nidines is described. They were screened for their antimicrobial susceptibility by the standard disc diffusion method of the World Health Organization (WHO) and the activities compared with that of standard strain of Escherichia coli NCTC 10418. The sensitive aminoguanidines were further subjected to the minimum inhibitory concentration (MIC) test.

Anti-Bacterial Agents↗
PubMed1976

[Species makeup, biological activity and antibiotic sensitivity of the microbes isolated from patients with a surgical infection].

Specimens from 227 patients with purulent surgical infections of various localization were tested. The microbial growth was observed in 87.6 per cent of the patients, staphylococci being found in 80.8 per cent of them. The plasma coagulating properties were detected in the staphylococci from 84.2 per cent of the patients among the total number of the staphylococcal isolates. Staphylococci were mostly isolated from the patients with osteomyelitis, infected wounds. Monocultures of the microbes and associations were found in 78.8 and 22.1 per cent of the patients respectively. The microbial associations were observed most often in cases with the diseases of the respiratory organs or abdominal cavity and osteomyelitis as compared to the cases with infected wounds. As dependent on the origin, the staphylococci in the patients of various groups differed by their phage type characteristics. Most of the isolates were sensitive to erythromycin, monomycin and neomycin (84 to 99.1 per cent). The antibiotic sensitive staphylococci were isolated more frequent from the cases with osteomyelitis and the diseases of the respiratory organs as compared to the other nosological forms.

Anti-Bacterial Agents↗
PubMed1994

Antimycobacterial susceptibility testing: present practices and future trends.

Along with the worldwide renewed interest in tuberculosis, the high incidence of non-tuberculous disease in HIV-infected patients and the continuing problem of disease caused by rapidly growing mycobacteria, there has been a renewed interest in mycobacterial susceptibility testing. This renewed interest stems from the needs both to provide accurate, reliable and timely susceptibility test information for the management of patients infected with these mycobacteria and to identify new and more effective antimycobacterial agents. Indeed, many new agents have already been identified and are currently used to treat these infections, but the conventional susceptibility testing methods, in many instances, have not been adequately evaluated for these new agents. Perhaps the time has come to give consideration to abandoning such time-honored practices and criteria as the proportion method, the 99% threshold, and "critical concentrations". New methods of susceptibility testing are in various stages of development and many of these methods have advantages and improvements over the existing methods. There is an increased understanding of the pathobiology of mycobacterial infections and an increased understanding of the pharmacokinetics of antimycobacterial agents and the mechanisms of action and resistance. This article gives an overview of the present practices and an assessment of the current needs and potential for the near future of antimycobacterial susceptibility testing.

Anti-Bacterial Agents↗
PubMed2005

Evaluation of the Vitek 2 system for identification and antimicrobial susceptibility testing of Staphylococcus spp.

The Vitek 2 system was assessed against reference methods with 197 methicillin-resistant Staphylococcus aureus from Belgian hospitals and 121 clinically significant blood culture isolates of Staphylococcus spp. Vitek 2 identified 95% of staphylococcal isolates correctly, detected oxacillin resistance with a sensitivity/specificity of 99/96%, and showed acceptable accuracy for susceptibility testing of five of eight other evaluable antibiotics. The median time for reporting results was 2 h 45 min for identification and 7 h for susceptibility tests.

Methicillin Resistance↗
PubMed1985

Determination of species- and laboratory-related interpretive breakpoints for doxycycline susceptibility testing using single-strain regression analysis.

Single-strain Regression Analysis (SRA) was performed for doxycycline on a total of 68 bacterial strains representing 16 different species. Species- and laboratory-related zone diameter breakpoints were determined and compared with histograms of zone diameter values obtained from 942 routine susceptibility tests. Calculated breakpoints were similar within individual species. When considering the homogeneity of susceptibility groups within bacterial species, the calculated breakpoints gave rise to relatively few interpretive errors. In contrast, general breakpoints for doxycycline as recommended by the Swedish Reference Group (SRG) (R less than = 20 mm and S greater than = 26 mm) would give rise to a high proportion of false interpretations in the present laboratory. Fifty-three per cent of H.influenzae strains would have been assigned to the wrong susceptibility group. For E.coli and K.pneumoniae, 22 and 35 per cent, respectively, would have been erroneously categorized using SRG breakpoints. E.cloacae and E.aerogenes would have been assigned another category in 39 and 50 per cent, respectively. The procedure for setting species-specific and laboratory-related interpretive breakpoints is described. Determination of species- and laboratory-related interpretive breakpoints using SRA provides a new approach towards improved accuracy of disc-diffusion susceptibility testing.

Doxycycline↗
PubMed1981

Facilitating quality control of the antimicrobial susceptibility test.

Standard reference strains of Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa were suspended in sterile deionized water and tested daily via disk agar diffusion for their antimicrobial susceptibilities. Inocula of E. coli and P. aeruginosa yielded acceptable results for up to 32 days; however, results on S. aureus were unacceptable due to loss of viability of the organism in water. E. coli and P. aeruginosa inocula, in water, can be used daily for quality control of the disk gear diffusion test.

Anti-Bacterial Agents↗
PubMed1984

beta-Lactamase detection in nine staphylococcal species.

Detection of beta-lactamase by four different techniques (two acidometric, one chromogenic cephalosporin, and one iodometric) was evaluated with 79 isolates of nine different species of staphylococci. Overall, each technique detected more positive isolates when beta-lactamase production had been induced with oxacillin before testing, and each technique performed equally well when organisms were tested after induction.

Humans↗
PubMed1991

Disk diffusion susceptibility test interpretive criteria for GR69153, a new catechol-substituted cephalosporin.

GR69153 disk diffusion tests with 10- and 30-micrograms disks were evaluated against 383 rapidly growing aerobic pathogens. Very high absolute agreement (96.1 to 98.1%) was observed between the MICs and disk zone diameters, and no false-susceptible results were encountered with the proposed criteria. The 30-micrograms GR69153 disk with a susceptible-zone diameter of greater than or equal to 17 mm (MIC correlate, less than or equal to 8 micrograms/ml) and a resistant-zone diameter of less than or equal to 13 mm (MIC correlate, greater than 16 micrograms/ml) is recommended. GR69153 had a spectrum of activity slightly wider than that of ceftazidime against the species tested.

Ceftazidime↗
PubMed1998

Evaluation of the BIOMIC video reader system for determining interpretive categories of isolates on the basis of disk diffusion susceptibility results.

The BIOMIC System (Giles Scientific, New York, N.Y.) includes software and a video-assisted plate reader that functions with a personal computer to automate, speed read, and interpret standard antibiotic disk diffusion test plates. The video reader helps standardize endpoints, speeds quantitative measurements by 40 to 90%, and reduces fatigue and transcription and interpretation errors (H. Wei-Fang, Am. Clin. Lab. 13:28-29, 1994). Organisms tested were isolated from patient specimens collected at Primary Children's Medical Center and included rapidly growing gram-positive and gram-negative strains that fulfill the National Committee for Clinical Laboratory Standards guidelines for disk diffusion susceptibility testing. A comparison of the plate reader-determined zones and visually measured zones for 3,339 organism-antimicrobial agent combinations was performed. The results demonstrated 0.1% (4 of 3,339) false-susceptible reads and 0.2% (6 of 3,339) false-resistant reads by the video reader compared with visual reads. Minor discrepancies (4.7% [156 of 3339]), resulting in category interpretation changes of intermediate to resistant or susceptible or changes of resistant or susceptible to intermediate, were also encountered. Of the discrepant results, 80.8% (139 of 172) resulted from a 3-mm or less zone diameter difference between the two different techniques. We conclude that the video-assisted plate reader is a reliable system for determining interpretative categories from zone diameters of standard antibiotic disk diffusion test plates.

Diffusion↗
PubMed1993

Bactericidal testing.

Recognition of the importance of bactericidal activity in certain clinical settings has generated a great deal of interest in bactericidal testing. Indeed, bactericidal testing can be of great use in a number of settings, but it also has the potential for being overutilized. Moreover, there are biologic and technical pitfalls inherent in bactericidal testing. This article addresses these issues and summarizes the progress toward standardization of these methods. Thoughtful and deliberate application of standardized bactericidal testing should make this controversial test much more useful in the future.

Microbial Sensitivity Tests↗
PubMedDate not supplied

[Penicillin resistance in strains of Streptococcus pneumoniae].

The values of minimal inhibitory concentration (MIC) of penicillin were determined using the agar-dilution method for 114 strains of Streptococcus pneumoniae isolated during 1994 in the patients treated in hospital and outpatient clinics. Diminished susceptibility to penicillin was determined in 50 (43.8%) strains. High level of penicillin resistance was observed in 12 (10.5%) strains. Streptococcus pneumoniae cannot any more be regarded as the agent with presumed susceptibility to penicillin, but every isolated strain must be tested.

Humans↗
PubMed1995

Microbial bioassays to assess the toxicity of solid-associated contaminants.

Due to the effects that sediment or soil matrices have on the bioavailability of compounds, it has been difficult to screen toxicity of solid-associated contaminants. The majority of microbial assays for testing toxicity of soils and sediments have been performed on water or solvent extracts. These procedures lead to a fractionation of the toxicity, which may underestimate or overestimate exposure routes and consequently potential adverse environmental effects. Recently, a solid-phase Microtox assay which eliminates the need for soil extracts and utilizes whole sediments or soils has been developed. This report describes a toxicity testing procedure using the inhibition of dehydrogenase enzyme activity of Bacillus cereus as test parameter. Studies with soil samples and a synthetic sediment spiked with organic contaminants and copper indicate the higher sensitivity of both solid-phase bioassays compared to water extract testing. A comparison of the results demonstrates that the B. cereus contact test is more sensitive for copper than the Photobacterium phosphoreum solid-phase test.

Bacillus cereus↗
PubMed1994

Antibiotic susceptibility testing by flow cytometry.

The first significant development in antibiotic susceptibility testing in recent years may be the flow cytofluorometric susceptibility test (FCST). The advanced analytical capability of the flow cytometer has provided the means to measure microbial diversity in culture. Membrane integrity and other indicators of microbial viability can be evaluated on a cell-by-cell basis. The FCST measures subtle dosage-response effects as well as the conventional minimum inhibitory and minimum bactericidal concentrations, simultaneously, in rapid tests which have the potential to supersede conventional techniques in terms of sensitivity and reproducibility.

Bacteria↗