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R N Jones

Publications and source records attributed to R N Jones.

At least 109 records · Page 6Linked to original sources
PubMed2001

Characterization of extended spectrum beta-lactamase-producing Klebsiella pneumoniae from Beijing, China.

Fourteen clinical isolates of Klebsiella pneumoniae with extended-spectrum beta-lactamases (ESBLs) were detected by the double disk synergy test and the Etest ESBL strip. Co-resistances included high MICs for aminoglycosides, fluoroquinolones, tetracyclines, and trimethoprim/sulphamethoxazole. Co-resistance was not observed in five of the 14 strains. These isolates were all genetically distinct as determined by the automated ribotyping method. Isoelectric focusing documented the presence of multiple beta-lactamases (one to four per isolate) with pIs ranging from 5.4 to 8.4. The majority of isolates contained beta-lactamases with pI values of 7.6 and 8.4 consistent with SHV-type ESBLs and an Amp C enzyme, respectively. Emerging ESBL strains in K. pneumoniae compromise the use of agents such as cefotaxime, ceftriaxone, ceftazidime in China; leading to the expansion of quality infection control practices and formulary management programmes to minimize clonal expansion.

Anti-Bacterial Agents↗
PubMed2001

GAR-936 (9-t-butylglycylamido-minocycline) susceptibility test development for streptococci, Haemophilus influenzae and Neisseria gonorrhoeae: preliminary guidelines and interpretive criteria.

GAR-936, a new semisynthetic derivative of minocycline, has earlier shown promising activity against tetracycline-resistant pathogens, including Streptococcus pneumoniae. In this study, the activity of GAR-936 was tested against a total of 514 tetracycline-susceptible and -resistant strains of S. pneumoniae, beta-haemolytic streptococci, viridans group streptococci, Haemophilus influenzae and Neisseria gonorrhoeae. All strains of H. influenzae, were inhibited by < or =2 mg/l of GAR-936, with MIC(90)s for all streptococci and gonococci of < or =0.5 mg/l. Scattergrams of GAR-936 comparing MICs by broth microdilution testing and zone diameters using 30 microg disks, confirmed the proposed susceptibility criteria of < or 2 mg/l or > or =20 mm zone diameter. Clinical trial results should be correlated with these preliminary in vitro results to confirm and/or adjust these susceptibility interpretive criteria for GAR-936 when testing fastidious streptococci, H. influenzae and N. gonorrhoeae.

Anti-Bacterial Agents↗
PubMed2001

Comparative antimicrobial spectrum and activity of BMS284756 (T-3811, a desfluoroquinolone) tested against 656 Enterobacteriaceae, including preliminary in vitro susceptibility test comparisons and development.

BMS284756 (T-3811), a novel des-F(6)-quinolone, was evaluated using isolates of Enterobacteriaceae from the SENTRY Antimicrobial Surveillance Program tested by Etest (AB BIODISK, Solna, Sweden), reference broth microdilution and disk diffusion (5-microg) methods. Ciprofloxacin, levofloxacin, gemifloxacin and gatifloxacin were also tested by broth microdilution as comparator antimicrobial agents within the same drug class. The 656 isolate collection included species from the genera Citrobacter, Enterobacter, Escherichia, Hafnia, Klebsiella, Morganella, Pantoea, Proteus, Providencia, Salmonella, and Serratia. BMS284756 was slightly less active than comparison fluoroquinolones against these isolates (MIC(90), 4 mg/l versus 0.06-2 mg/l). However, at a proposed susceptible breakpoint of < or =4 mg/l, 90.7% of the isolates processed were susceptible to BMS284756, demonstrating an equivalent spectrum of activity to all other agents except gemifloxacin (86.6%). In general, isolates requiring >4 mg/l of BMS284756 for inhibition of growth were also less susceptible to the comparators suggesting cross-resistance is common between des-F(6)- and fluoro-quinolones. Excellent correlation was observed between broth microdilution MIC results and 5-microg disk zone diameters (r=0.94), and between broth microdilution dilution and Etest MIC values (r=0.96). In conclusion, BMS284756 has an activity and spectrum similar to contemporary fluoroquinolones and in vitro test methods (NCCLS, Etest) appear accurate and reproducible

Anti-Infective Agents↗
PubMed2001

Antimicrobial activity of BMS 284756 (T-3811) against Neisseria gonorrhoeae tested by three methods.

The potency of BMS 284756, a novel des-F(6)-quinolone, was tested against 137 clinical isolates of Neisseria gonorrhoeae including 50 strains observed to be resistant to ciprofloxacin and other newer quinolones. The gonococci were tested using NCCLS methods (agar dilution, disk diffusion) and Etest. BMS 284756 potency versus N. gonorrhoeae was generally two- to four-fold greater than ciprofloxacin. Penicillin resistance in the absence of ciprofloxacin resistance did not affect BMS 284756 activity. However, elevated ciprofloxacin MICs were associated with higher BMS 284756 MIC results as follows (BMS 284756 MIC(50)/MIC range in mg/l): ciprofloxacin-susceptible strains (0.016 or 0.03/0.004-0.06), ciprofloxacin-intermediate strains (0.06 or 0.12/0.008-0.25) and ciprofloxacin-resistant strains (0.12 or 0.5/0.12-1). Etest MICs were routinely lower than those produced by the reference agar dilution method, but the correlation coefficient remained acceptable (r = 0.87). Similarly acceptable correlation was achieved with 5 microg disk zone diameters (r = 0.78), where all zones were > or = 28 mm (MIC < or = 1 mg/l). In conclusion, BMS 284756 was very active against N. gonorrhoeae (MIC(50) 0.03 mg/l overall) including ciprofloxacin-resistant strains and could be considered as a single-dose therapeutic option for gonorrhoea.

Anti-Infective Agents↗
PubMed2001

Education bias in the mini-mental state examination.

Education is correlated with cognitive status assessment. Concern for test bias has led to questions of equivalent construct validity across education groups. Following the work of previous researchers, we submitted Mini-Mental State Examination (MMSE) responses to external validation analyses. Subjects were older participants in the Epidemiologic Catchment Area study (age 50-98). Little evidence for test bias against those with low education was found. The correlation of MMSE scores and age was equivalent across high- and low-education groups (-.29 vs. -.27, p = .48), as was the correlation of MMSE scores and activities of daily living (ADL) functioning (-.23 vs. -.27, p = .42). The MMSE displayed significantly higher internal consistency reliability in the low-education group (.75 vs. .72, p = .04). The MMSE did not predict functional decline over 1 year or mortality over 13 years differently by level of educational attainment. Evidence for sex bias was found. The MMSE was more highly correlated with age among women than among men (-.28 vs. -.21, p < .001). The MMSE was more highly correlated with ADL impairment among women than among men (-.30 vs. -.17, p = .01). The MMSE predicted mortality differently according to participant sex (p = .053). The lack of evidence for bias provides little support to proposals to adjust MMSE scores according to level of education.

Activities of Daily Living↗
PubMed2001

Fluorescein dermofluorometry for the assessment of diabetic microvascular disease.

BACKGROUND/AIMS: Fluorescein dermofluorometry can be used to relate the uptake of fluorescein in the skin to blood flow. We have characterized the uptake of the dye by a wash-in time constant that is inversely proportional to the local blood flow. The purpose of this study was to explore the use of dermofluorometry in the assessment of patients with diabetic microvascular disease. METHODS: Fluorescein dermofluorometry was performed in four groups of patients: non-diabetic control patients, diabetic control patients, diabetic patients with chronic foot ulcers, and diabetic patients with acute foot ulcers. The outcomes of the patients with foot ulcers were documented 4-14 months after participation. Following an intravenous injection of sodium fluorescein, the change in the fluorescein signal with time was continuously measured at the plantar surface of the foot. Both the initial slope of the signal and the wash-in time constant were calculated in each subject. RESULTS: Significant differences in the wash-in time constant were found between diabetic and non-diabetic subjects and between diabetic subjects with and without foot ulcers. Of the eight patients with foot ulcers, two of them did not display an early wash-out in the dermofluorometer signal and later both required amputations. CONCLUSION: The fluorescein wash-in time constant demonstrated better correlation with the presence of diabetic microvascular disease than did the initial slope of the signal. Differences in the wash-in time constants of non-diabetic and diabetic subjects support the hemodynamic hypothesis for the development of microvascular disease. The indication of early wash-out of the fluorescein signal may also be useful in the prediction of ulcer healing.

Diabetic Angiopathies↗
PubMed2001

Antimicrobial resistance in viridans group streptococci among patients with and without the diagnosis of cancer in the USA, Canada and Latin America.

OBJECTIVE: To investigate antimicrobial resistance in viridans group streptococci (VGS) among patients with and without the diagnosis of cancer in the USA, Canada and Latin America. METHODS: All bloodstream isolates of VGS collected from SENTRY centers in the Western Hemisphere between January 1997 and December 1999 were tested by reference broth microdilution methods (NCCLS). Results for isolates from patients with cancer were compared to those from other patient populations. RESULTS: Overall, 438 unique patient bloodstream isolates of VGS were collected during the study. Percentage susceptible/MIC90 (mg/L) values for antimicrobials tested were as follows: penicillin, 66/1; erythromycin, 60/4; clindamycin, 92/0.12; cefepime, 86/1; trimethoprim-sulfamethoxazole, 80/2; ciprofloxacin, 44/> 2; gatifloxacin, 98/0.5; and vancomycin, 100/1. Of these isolates, 70 (16%) were confirmed to be from cancer patients. VGS isolates from cancer patients were less susceptible to most antimicrobials tested than were isolates from non-cancer patients. The greatest differences in susceptibility rates for cancer- versus non-cancer-associated VGS isolates were seen for ciprofloxacin (34% versus 46%, P = 0.07) and trimethoprim-sulfamethoxazole (64% versus 83%, P < 0.001), two agents which are often used for prophylaxis or as presumptive therapy in cancer patients. CONCLUSIONS: Susceptibility rates for VGS isolates from cancer patients are lower than those for isolates from patients without a cancer diagnosis. These differences are greatest for agents that have seen widespread prophylactic and empirical use. Ongoing surveillance of VGS infections in this patient population is important and should help to guide therapy decisions.

Anti-Bacterial Agents↗
PubMed2001

In vitro Gram-positive antimicrobial activity of evernimicin (SCH 27899), a novel oligosaccharide, compared with other antimicrobials: a multicentre international trial.

The antimicrobial activity of evernimicin (formerly SCH 27899), a novel oligosaccharide antimicrobial of the everninomicin class, was evaluated against four groups of Gram-positive pathogens: (i) Streptococcus pneumoniae (n = 1452); (ii) methicillin- or oxacillin-resistant Staphylococcus aureus (MRSA) and coagulase-negative staphylococci (MR-CoNS; n = 1427); (iii) enterococci (n = 1517); and (iv) non-pneumococcal streptococci (n = 1388), using the Etest method at each study centre throughout Eastern and Western Europe, Scandinavia, South Africa, Turkey and North America. Comparative MICs were determined for a variety of reference compounds, including vancomycin, quinupristin/dalfopristin, chloramphenicol, penicillin, ampicillin, oxacillin, ceftriaxone and ciprofloxacin. Evernimicin was highly active against all strains tested, with MIC90 values < or = 1.0 mg/L, ranging from 0.047 mg/L against S. pneumoniae to 1.0 mg/L against MRSA/MR-CoNS and enterococci. Compared with the reference agents, the MIC90 of evernimicin were lower against all species. Against MRSA and MR-CoNS the MIC90s of evernimicin, quinupristin/dalfopristin and vancomycin (the three most active agents) were 1.0, 1.5 and 3.0 mg/L, respectively. Against all species tested, the relative activities and spectra of these agents were: evernimicin > vancomycin > quinupristin/dalfopristin. The Etest proved to be reliable and reproducible, despite occasional interpretive difficulties caused by observer inexperience. Quality control results were excellent among the 33 participant sites. The results of this in vitro, multicentre, multinational study demonstrate that evernimicin possesses high antimicrobial activity against Gram-positive organisms that compares favourably with established antibacterial treatments and newer agents such as quinupristin/dalfopristin. Further clinical investigations of everninomicin class compounds appear warranted.

Aminoglycosides↗
PubMed2001

In vitro activities of posaconazole (Sch 56592) compared with those of itraconazole and fluconazole against 3,685 clinical isolates of Candida spp. and Cryptococcus neoformans.

Posaconazole is a new investigational triazole with broad-spectrum antifungal activity. The in vitro activities of posaconazole were compared with those of itraconazole and fluconazole against 3,685 isolates of Candida spp. (3,312 isolates) and C. neoformans (373 isolates) obtained from over 70 different medical centers worldwide. The MICs of the antifungal drugs were determined by broth microdilution tests performed according to the National Committee for Clinical Laboratory Standards method using RPMI 1640 as the test medium. Posaconazole was very active against all Candida spp. (MIC at which 90% of the isolates were inhibited [MIC(90)], 0.5 microg/ml; 97% of MICs were < or =1 microg/ml) and C. neoformans (MIC(90), 0.5 microg/ml; 100% of MICs were < or =1 microg/ml). Candida albicans was the most susceptible species of Candida (MIC(90), 0.06 microg/ml), and Candida glabrata was the least susceptible (MIC(90), 4 microg/ml). Posaconazole was more active than itraconazole and fluconazole against all Candida spp. and C. neoformans. These results provide further evidence for the spectrum and potency of posaconazole against a large and geographically diverse collection of clinically important fungal pathogens.

Antifungal Agents↗
PubMed2001

Antimicrobial susceptibility testing of clinical isolates of Bordetella pertussis from northern California: report from the SENTRY Antimicrobial Surveillance Program.

Reports of an increased clinical incidence of pertussis and the development of resistance by Bordetella pertussis to erythromycin prompted the collection and testing of recent clinical isolates from patients in northern California against a range of antimicrobial agents by the Etest (AB BIODISK, Solna, Sweden) method. All isolates were fully susceptible to all eight agents tested (MIC, <or=0.38 microg/ml), including newer fluoroquinolones, such as gatifloxacin (MIC of which 90% of the isolates tested are inhibited, 0.006 microg/ml), which may be used in cases of adolescent or adult pertussis. Continued surveillance of B. pertussis isolates appears to be a prudent practice.

Adolescent↗
PubMed2001

Activities of BMS 284756 (T-3811) against Haemophilus influenzae, Moraxella catarrhalis, and Streptococcus pneumoniae isolates from SENTRY antimicrobial surveillance program medical centers in Latin America (1999).

The antimicrobial activity of BMS 284756, a novel des-F(6)-quinolone, was comparatively evaluated against 257 Streptococcus pneumoniae, 198 Haemophilus influenzae, and 88 Moraxella catarrhalis strains isolated in Latin America between July and September of 1999 as part of the SENTRY Antimicrobial Surveillance Program. Nearly 28.0% of S. pneumoniae strains were nonsusceptible to penicillin. The rank order of quinolone potency versus S. pneumoniae was BMS 284756 (MIC at which 90% of isolates were inhibited [MIC(90)], 0.12 microg/ml) > trovafloxacin (MIC(90), 0.25 microg/ml) > gatifloxacin (MIC(90), 0.5 microg/ml) > levofloxacin and ciprofloxacin (MIC(90), 1 to 2 microg/ml). All S. pneumoniae strains that were not susceptible to other quinolones were inhibited by BMS 284756 at < or = 2 microg/ml. The overall prevalence of beta-lactamase production was 15.2% in H. influenzae and 98.9% in M. catarrhalis. BMS 284756 showed excellent potency and spectrum against this group of pathogens, inhibiting all isolates at < or = 0.12 microg/ml. BMS 284756 exhibited activity similar to those displayed by the new fluoroquinolones, such as levofloxacin, trovafloxacin, or gatifloxacin, and could be a therapeutic option for empirical treatment of community-acquired respiratory tract infections.

Anti-Infective Agents↗
PubMed2001

Contemporary assessment of antimicrobial susceptibility testing methods for polymyxin B and colistin: review of available interpretative criteria and quality control guidelines.

The emergence of infections caused by multidrug-resistant Pseudomonas aeruginosa and Acinetobacter spp. has necessitated the search for alternative parenteral agents such as the polymyxins. The National Committee for Clinical Laboratory Standards (NCCLS) documents do not currently provide interpretative criteria for the testing of the polymyxins, colistin and polymyxin B. Therefore, an evaluation of the antimicrobial activity of colistin and polymyxin B was initiated using 200 bloodstream infection pathogens collected through the SENTRY Antimicrobial Surveillance Program. All susceptibility tests were performed according to the NCCLS recommendations. Polymyxin B and colistin displayed a nearly identical spectrum of activity, exhibiting excellent potency against P. aeruginosa (MIC(90), 2 microg/ml) and Acinetobacter sp. (MIC(90), 2 microg/ml). In contrast, they showed limited activity against some other nonfermentative bacilli such as Burkholderia cepacia (MIC(90), >/=128 microg/ml). Excellent correlation was achieved between broth microdilution and agar dilution tests (r = 0.96 to 0.98); 94.3% of the results were +/-1 log(2) dilution between the methods used for both compounds. At a resistance breakpoint of >/=4 microg/ml for both agents, unacceptable false-susceptible or very major errors were noted for colistin (5%) and polymyxin B (6%). Modified zone criteria for colistin (</=11 and >/=14 mm) and polymyxin B (</=10 and >/=14 mm) were suggested, but some degree of error persisted (>/=3.5%). It is recommended that all susceptible disk diffusion results be confirmed by MIC tests using the preferred reference NCCLS method. The quality control (QC) ranges listed in the product package insert require an adjusted range by approximately 3 mm for both NCCLS gram-negative quality control strains. This evaluation of in vitro susceptibility test methods for the polymyxin class drugs confirmed continued serious testing error with the disk diffusion method, the possible need for breakpoint adjustments, and the recalculation of disk diffusion QC ranges. Clinical laboratories should exclusively use MIC methods to assist the therapeutic application of colistin or polymyxin B until disk diffusion test modifications are sanctioned and published by the NCCLS.

Anti-Bacterial Agents↗
PubMed2001

Comparison of the Vitek Gram-Positive Susceptibility 106 card and the MRSA-screen latex agglutination test for determining oxacillin resistance in clinical bloodstream isolates of Staphylococcus aureus.

The Vitek automated susceptibility testing system with a modified Gram-Positive Susceptibility (GPS) 106 Card (bioMerieux Vitek, Inc., Hazelwood, Mo.) and a rapid slide latex agglutination test (MRSA-Screen; Denka Seiken Co., Ltd., Tokyo, Japan) were evaluated for their ability to detect oxacillin resistance in Staphylococcus aureus. The oxacillin-salt agar screen (OS) test, the reference broth microdilution method, and the detection of the mecA gene by PCR were compared with the commercial products. A total of 200 contemporary (1999) bloodstream infection isolates were collected from the SENTRY Antimicrobial Surveillance Program, representing diverse geographic areas throughout the world. Among the 99 mecA-positive isolates, 3 isolates were found negative by the MRSA-Screen. Another two isolates did not grow on OS plates and had MICs of 0.5 and 2 microg/ml with the Vitek GPS card. All 101 mecA-negative isolates were also found negative by the MRSA-Screen and were categorized as susceptible by the GPS card. Overall, the MRSA-Screen, GPS card, and OS test had sensitivities of 96.9, 98.0, and 98.0% and specificities of 100.0, 100.0, and 98.0%, respectively. MRSA-Screen was a rapid (</=15 min) and simple test to perform, and the GPS card provided results in <8 h. Both methods were sensitive and specific for detecting staphylococcal oxacillin resistance in the clinical microbiology laboratory.

Bacteremia↗
PubMed2001

Comparison of the Vitek gram-positive susceptibility 106 card, the MRSA-Screen latex agglutination test, and mecA analysis for detecting oxacillin resistance in a geographically diverse collection of clinical isolates of coagulase-negative staphylococci.

The Vitek automated susceptibility testing system with a modified gram-positive susceptibility (GPS) 106 card (bioMerieux Vitek, Inc., Hazelwood. Mo.) and a rapid slide latex agglutination test (MRSA-Screen test; Denka Seiken Co., Ltd., Tokyo, Japan) were evaluated for their abilities to detect oxacillin resistance in coagulase-negative staphylococci (CoNS). The reference broth microdilution method and the detection of the mecA gene by PCR ("gold standard" reference result) were used to compare the results obtained with the commercial products. A total of 123 clinical isolates consisting of eight species were selected from U.S. surveillance collections. Among the mecA-positive isolates (95 strains), 30 isolates were initially negative on the MRSA-Screen test read at 3 min. When the agglutination reaction was extended for 10 min, 26 of the 30 isolates became positive. For a different four isolates, the oxacillin MIC was < or =0.25 microg/ml on the Vitek GPS 106 card. Among the mecA-negative isolates (28 strains), for two Staphylococcus warneri, two S. lugdunensis, and two S. saprophyticus strains MICs were > or =0.5 microg/ml by the reference broth microdilution method. Four of these isolates were also categorized as resistant with the Vitek GPS 106 card and two isolates were positive by the MRSA-Screen test. Overall, the MRSA-Screen test, GPS 106 card, and reference broth microdilution method had sensitivities of 95.7 (result at 10 min), 95.7, and 100%, respectively, and specificities of 92.8, 85.7, and 78.5%, respectively. Although the MRSA-Screen test required a slight procedural modification, both commercial methods achieved a sensitivity and specificity at detecting oxacillin resistance in CoNS at a level that was acceptable for clinical laboratory use.

Bacterial Proteins↗
PubMed2001

Evaluation of Etest method for determining posaconazole MICs for 314 clinical isolates of Candida species.

The performance of the Etest for posaconazole (SCH 56592) susceptibility testing of 314 isolates of Candida spp. was assessed against the National Committee for Clinical Laboratory Standards (NCCLS) microdilution broth method. The NCCLS method employed RPMI 1640 broth medium, and MICs were read after incubation for 48 h at 35 degrees C. MICs were determined by Etest for all 314 isolates with RPMI agar containing 2% glucose (RPG agar) and were read after incubation for 48 h at 35 degrees C. The Candida isolates included C. albicans (n = 174), C. glabrata (n = 57), C. tropicalis (n = 31), C. parapsilosis (n = 39), C. krusei (n = 5), C. guilliermondii (n = 6), and C. lusitaniae (n = 2). The Etest results correlated well with reference MICs. Overall agreement was 95%, and agreements for individual species were as follows: C. krusei, 100%; C. albicans, 98%; C. tropicalis, 97%; C. glabrata, 93%; C. parapsilosis, 85%; C. guilliermondii, 83%; and C. lusitaniae, 50%. The problem of trailing end points was minimized with RPG agar, and good agreement with broth dilution MICs was obtained when discernible growth within an established ellipse was ignored. The Etest method using RPG agar appears to be a useful method for determining posaconazole susceptibilities of Candida species.

Antifungal Agents↗
PubMed2001

Standardization of broth microdilution and disk diffusion susceptibility tests for Actinobacillus pleuropneumoniae and Haemophilus somnus: quality control standards for ceftiofur, enrofloxacin, florfenicol, gentamicin, penicillin, tetracycline, tilmicosin, and trimethoprim-sulfamethoxazole.

Quality control (QC) standards for the in vitro antimicrobial susceptibility testing of two fastidious veterinary pathogens, Actinobacillus pleuropneumoniae and Haemophilus somnus, were developed in a multilaboratory study according to procedures established by the National Committee for Clinical Laboratory Standards for broth microdilution and disk diffusion testing. The medium recommended for the broth microdilution testing is cation-adjusted Mueller-Hinton broth supplemented with 2% lysed horse blood, 2% yeast extract, and 2% supplement C. This medium has been designated veterinary fastidious medium. The medium recommended for the disk diffusion testing is chocolate Mueller-Hinton agar. The recommended QC organisms are A. pleuropneumoniae ATCC 27090 and H. somnus ATCC 700025. The QC MICs of ceftiofur, enrofloxacin, florfenicol, gentamicin, penicillin, tetracycline, tilmicosin, and trimethoprim-sulfamethoxazole were determined for each isolate, as were the zone size ranges. Of the results from the participating laboratories, 94.0% of the zone diameter results and 97.0% of the MIC results fell within the suggested QC ranges for all compounds. These QC guidelines should allow greater accuracy in interpreting results when testing these antimicrobial agents against fastidious pathogens.

Actinobacillus Infections↗