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Kahlmeter, Gunnar
Publications (4 of 4) Show all publications
Sturegård, E., Ängeby, K. A., Werngren, J., Jureen, P., Kronvall, G., Giske, C. G., . . . Schön, T. (2015). Little difference between minimum inhibitory concentrations of Mycobacterium tuberculosis wild-type organisms determined with BACTEC MGIT 960 and Middlebrook 7H10. Clinical Microbiology and Infection, 21(2), Article ID 148.e5.
Open this publication in new window or tab >>Little difference between minimum inhibitory concentrations of Mycobacterium tuberculosis wild-type organisms determined with BACTEC MGIT 960 and Middlebrook 7H10
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2015 (English)In: Clinical Microbiology and Infection, ISSN 1198-743X, E-ISSN 1469-0691, Vol. 21, no 2, article id 148.e5Article in journal (Refereed) Published
Abstract [en]

The MIC wild-type (WT) distribution for Mycobacterium tuberculosis in BACTEC 960 MGIT is not defined, which may result in poor reproducibility for drug susceptibility testing (DST), as several DST methods with different breakpoints are in use. In a comparison between MGIT and Middlebrook 7H10 medium of seven first-and second-line drugs, including 133 MIC determinations of 15 WT isolates, we found an agreement of 91.7% within +/- one MIC dilution step. The results confirm the agreement in MIC testing between 7H10 and MGIT and indicate that breakpoints could be harmonized in order to avoid misclassification. Clinical Microbiology and Infection (C) 2014 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

Keyword
Drug susceptibility testing, epidemiological cut off, minimal inhibitory concentration, normalised resistance
National Category
Clinical Medicine
Identifiers
urn:nbn:se:uu:diva-303583 (URN)10.1016/j.cmi.2014.08.021 (DOI)000381514200006 ()
Available from: 2016-09-30 Created: 2016-09-20 Last updated: 2017-11-30Bibliographically approved
Bengtsson, S., Naseer, U., Sundsfjord, A., Kahlmeter, G. & Sundqvist, M. (2012). Sequence types and plasmid carriage of uropathogenic Escherichia coli devoid of phenotypically detectable resistance. Journal of Antimicrobial Chemotherapy, 67(1), 69-73.
Open this publication in new window or tab >>Sequence types and plasmid carriage of uropathogenic Escherichia coli devoid of phenotypically detectable resistance
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2012 (English)In: Journal of Antimicrobial Chemotherapy, ISSN 0305-7453, E-ISSN 1460-2091, Vol. 67, no 1, p. 69-73Article in journal (Refereed) Published
Abstract [en]

Objectives

Plasmids play a major role in the dissemination of antibiotic resistance, and several studies have shown the association between specific resistance mechanisms and certain plasmid types and/or Escherichia coli lineages. This study describes the distribution of plasmids, replicon types, sequence types (STs) and ST complexes (STCs) of E. coli devoid of phenotypic resistance to 24 antibiotics.

Methods

Eighty E. coli isolates from urinary tract infections from four European countries were selected because of their lack of phenotypically detectable antibiotic resistance. The isolates were characterized to the phylogenetic group level using PCR and to ST by multilocus sequence typing. Plasmid carriage was assessed using S1 nuclease PFGE profiling and PCR-based replicon typing.

Results

Plasmids were detected in only 38/80 (47%) of the isolates; one (n = 18), two (n = 14), three (n = 5) and four (n = 1) plasmids. Six different replicon types were identified, the most common being a combination of IncFII and IncFIB. Most isolates belonged to phylogenetic group B2 and STC73 (n = 20), STC95 (n = 7) and ST420 (n = 6). A high proportion of STC73 isolates (75%) was devoid of plasmids. No association could be found between specific STs and replicon type.

Conclusions

A large proportion of E. coli strains phenotypically devoid of antibiotic resistance were plasmid naive. Those isolates that harboured plasmids displayed replicon types similar to those of resistant isolates, but the distributions of STs and STCs were different. This may indicate chromosomally encoded mechanisms important for the stabilization of plasmids harbouring antibiotic resistance.

National Category
Clinical Medicine
Identifiers
urn:nbn:se:uu:diva-164699 (URN)10.1093/jac/dkr421 (DOI)000300833700011 ()21980069 (PubMedID)
Available from: 2011-12-22 Created: 2011-12-22 Last updated: 2017-12-08Bibliographically approved
Titelman, E., Iversen, A., Kahlmeter, G. & Giske, C. G. (2011). Antimicrobial susceptibility to parenteral and oral agents in a largely polyclonal collection of CTX-M-14 and CTX-M-15-producing Escherichia coli and Klebsiella pneumoniae. Acta Pathologica, Microbiologica et Immunologica Scandinavica (APMIS), 119(12), 853-863.
Open this publication in new window or tab >>Antimicrobial susceptibility to parenteral and oral agents in a largely polyclonal collection of CTX-M-14 and CTX-M-15-producing Escherichia coli and Klebsiella pneumoniae
2011 (English)In: Acta Pathologica, Microbiologica et Immunologica Scandinavica (APMIS), ISSN 0903-4641, E-ISSN 1600-0463, Vol. 119, no 12, p. 853-863Article in journal (Refereed) Published
Abstract [en]

Activity of oral and parenteral antimicrobials against consecutively isolated extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli (n = 149) and Klebsiella pneumoniae (n = 20) was determined, and susceptibility test methods were compared for parenteral beta-lactams. Polymerase chain reaction (PCR) targeting bla(CTX-M), bla(SHV) and bla(TEM), and DNA sequencing and epidemiological typing with pulsed-field gel electrophoresis were performed. PCR targeting pabB was screened for E. coli O25b-ST131. Minimum inhibitory concentrations (MICs) were determined using Etest and broth microdilution. Disc diffusion was performed according to European Committee on Antimicrobial Susceptibility Testing (EUCAST). Dominating genotypes were bla(CTX-M-15) (75%) and bla(CTX-M-14) (23%). Four E. coli clusters (7-18 isolates) were found. Forty-two per cent of E. coli belonged to O25b-ST131. Ciprofloxacin resistance was 72%, trimethoprim resistance was 70%. Among E. coli, resistance to mecillinam (13%), nitrofurantoin (7%) and fosfomycin (3%) was low, although resistance was high in K. pneumoniae (25%, 60%, 85%). Susceptibility to ertapenem was 99%, piperacillin-tazobactam 91%, tigecycline 96% and temocillin 76%. Susceptibility rates obtained with broth microdilution and Etest were in agreement for cefotaxime (2 vs 1%) and ceftazidime (9 vs 11%), but not for piperacillin-tazobactam (59 vs 91%). With disc diffusion major errors occurred with piperacillin-tazobactam (18/169). Several therapeutic alternatives exist for ESBL-producing E. coli, but few exist for K. pneumoniae. Disc diffusion and Etest can accurately predict susceptibility to cefotaxime and ceftazidime, but not to piperacillin-tazobactam with the present breakpoints.

Keyword
ESBL, interpretive reading, SHV, ceftazidime, cefotaxime
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:uu:diva-163653 (URN)10.1111/j.1600-0463.2011.02766.x (DOI)000297099700004 ()
Available from: 2011-12-14 Created: 2011-12-13 Last updated: 2017-12-08Bibliographically approved
Sundqvist, M., Geli, P., Andersson, D. I., Sjölund-Karlsson, M., Runehagen, A., Cars, H., . . . Kahlmeter, G. (2010). Little evidence for reversibility of trimethoprim resistance after a drastic reduction in trimethoprim use. Journal of Antimicrobial Chemotherapy, 65(2), 350-360.
Open this publication in new window or tab >>Little evidence for reversibility of trimethoprim resistance after a drastic reduction in trimethoprim use
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2010 (English)In: Journal of Antimicrobial Chemotherapy, ISSN 0305-7453, E-ISSN 1460-2091, Vol. 65, no 2, p. 350-360Article in journal (Refereed) Published
Abstract [en]

Objectives The worldwide rapid increase in antibiotic-resistant bacteria has made efforts to prolong the lifespan of existing antibiotics very important. Antibiotic resistance often confers a fitness cost in the bacterium. Resistance may thus be reversible if antibiotic use is discontinued or reduced. To examine this concept, we performed a 24 month voluntary restriction on the use of trimethoprim-containing drugs in Kronoberg County, Sweden. Methods The intervention was performed on a 14 year baseline of monthly data on trimethoprim resistance and consumption. A three-parameter mathematical model was used to analyse the intervention effect. The prerequisites for reversion of resistance (i.e. fitness cost, associated resistance and clonal composition) were studied on subsets of consecutively collected Escherichia coli from urinary tract infections. Results The use of trimethoprim-containing drugs decreased by 85% during the intervention. A marginal but statistically significant effect on the increase in trimethoprim resistance was registered. There was no change in the clonal composition of E. coli and there was no measurable fitness cost associated with trimethoprim resistance in clinical isolates. The frequency of associated antibiotic resistances in trimethoprim-resistant isolates was high. Conclusions A lack of detectable fitness cost of trimethoprim resistance in vitro together with a strong co-selection of other antibiotics could explain the rather disappointing effect of the intervention. The result emphasizes the low possibility of reverting antibiotic resistance once established and the urgent need for the development of new antibacterial agents.

Place, publisher, year, edition, pages
Oxford University Press, 2010
Keyword
intervention, Escherichia coli, population dynamic
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:uu:diva-112599 (URN)10.1093/jac/dkp387 (DOI)000273892600030 ()19900952 (PubMedID)
Note
Epub ahead of print 8 November 2009Available from: 2010-01-15 Created: 2010-01-15 Last updated: 2017-12-12Bibliographically approved
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