| 1. |
- Andersson, Madelen, et al.
(författare)
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Outbreak of a beta-lactam resistant non-typeable Haemophilus influenzae sequence type 14 associated with severe clinical outcomes
- 2015
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Ingår i: BMC Infectious Diseases. - : BioMed Central. - 1471-2334. ; 15
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Tidskriftsartikel (refereegranskat)abstract
- Background: During October 2011 several residents and staff members at a long-term care facility (LTCF) for elderly fell ill with respiratory symptoms. Several of the residents required hospitalization and one died. Non-typeable Haemophilus influenzae (NTHi) was identified as the causative pathogen. Methods: A descriptive analysis of the outbreak and countermeasures was performed. For each identified bacterial isolate implied in the outbreak, standard laboratory resistance testing was performed, as well as molecular typing and phylogenetic analysis. Results: The identified H. influenzae was beta-lactamase negative but had strikingly high MIC-values of ampicillin, cefuroxime and cefotaxime. All isolates displayed the same mutation in the ftsI gene encoding penicillin-binding protein (PBP) 3, and all but one were identified as sequence type 14 by Multilocus Sequence Typing (MLST). In total 15 individuals in connection to the LTCF; 8 residents, 6 staff members and one partner to a staff member were colonized with the strain. Conclusion: This report illustrates the existence of non-typeable H. influenzae with high virulence, and furthermore emphasizes the importance of continuous surveillance of possible outbreaks in health care facilities and prompt measures when outbreaks occur.
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| 2. |
- Bengtsson, Stina, et al.
(författare)
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Sequence types and plasmid carriage of uropathogenic Escherichia coli devoid of phenotypically detectable resistance
- 2012
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Ingår i: Journal of Antimicrobial Chemotherapy. - : Oxford University Press (OUP). - 0305-7453 .- 1460-2091. ; 67:1, s. 69-73
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 3. |
- Bengtsson, S., et al.
(författare)
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Validation of EUCAST zone diameter breakpoints against reference broth microdilution
- 2014
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Ingår i: Clinical Microbiology and Infection. - : Elsevier BV. - 1198-743X .- 1469-0691. ; 20:6, s. O353-O360
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Tidskriftsartikel (refereegranskat)abstract
- The European Committee on Antimicrobial Susceptibility Testing (EUCAST) began harmonizing clinical breakpoints in Europe 2002. In 2009, work to develop a disc diffusion method began and the first disc diffusion breakpoints calibrated to EUCAST clinical MIC breakpoints were published in December 2009. In this study we validated EUCAST clinical zone diameter breakpoints against the International Standard Organization (ISO) reference broth microdilution. A collection of 544 isolates (238 Gram-negative and 306 Gram-positive) were tested against a panel of antimicrobial agents. Antimicrobial susceptibility testing was performed with broth microdilution as described by ISO and disc diffusion in accordance with EUCAST methodology. Inhibition zone diameters and MIC values were interpreted and categorized (S, I and R) according to EUCAST clinical breakpoint table version 2.0. Categorical agreement (CA) as well as minor (mD), major (MD) and very major (VMD) discrepancies were determined. There was in general good correlation between susceptibility test results obtained with disc diffusion and broth microdilution. Overall CA was 97.3% for all combinations of organisms and antimicrobial agents (n = 5231) and the overall discrepancy rates were 110 (2.1%) mD, 24 (0.5%) MD and 7 (0.1%) VMD. The overall CA for Gram-positive and Gram-negative organisms were 98.7% (2346 tests) and 96.2% (2942 tests), respectively. Seven VMD were observed, five for Gram-positive organisms (coagulase negative staphylococci (n = 2) and Staphylococcus aureus (n = 3)) and two for Gram-negative organisms (Pseudomonas aeruginosa). Minor discrepancies were mainly observed in Gram-negatives and were related to different antimicrobial agents and species.
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| 4. |
- Bieber, L., et al.
(författare)
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Staphylococcus lugdunensis in several niches of the normal skin flora
- 2010
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Ingår i: Clinical Microbiology and Infection. - : Elsevier BV. - 1198-743X .- 1469-0691. ; 16:4, s. 385-388
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Tidskriftsartikel (refereegranskat)abstract
- Staphylococcus lugdunensis is a coagulase-negative staphylococcus (CNS). Its pathogenicity and virulence are more similar to Staphylococcus aureus than to a CNS. It causes severe infections with high mortality, such as endocarditis, but more often painful and prolonged skin- and soft-tissue infections. Little is known of its normal habitat. Whether it is an integral part of the normal skin flora like many other CNS has been questioned, since it is rarely seen in blood cultures. This study was designed to determine whether S. lugdunensis has a niche in the normal skin flora and to compare S. lugdunensis and S. aureus in these niches.From 75 healthy subjects in Kronoberg County, Sweden, 525 swabs were obtained from the nose, axilla, perineum, groin, breast, toe and nail bed of the first toe. Significantly more of the 525 skin samples as well as of the 75 healthy subjects yielded S. lugdunensis (50/75) as opposed to S. aureus.(16/75). Swabs from the nose frequently yielded S. aureus, but only rarely S. lugdunensis. Swabs from the groin and the lower extremities, especially the nail bed of the first toe, often yielded S. lugdunensis but rarely S. aureus. This study shows that S. lugdunensis is an integral part of the normal skin flora, primarily of the lower abdomen and extremities, and that the niches of this coagulase-negative staphylococcus are distinctly different from those of S. aureus. The predominant niches of S. lugdunensis explain why the bacterium is an uncommon contaminant of blood cultures.
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| 5. |
- Bonnedahl, Jonas, 1970-, et al.
(författare)
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Dissemination of Escherichia coli with CTX-M Type ESBL between Humans and Yellow-Legged Gulls in the South of France
- 2009
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Ingår i: PLOS ONE. - San Francisco, CA, United States : Public Library of Science (PLoS). - 1932-6203. ; 4:Article number: e5958
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Tidskriftsartikel (refereegranskat)abstract
- Extended Spectrum beta-Lactamase (ESBL) producing Enterobacteriaceae started to appear in the 1980s, and have since emerged as some of the most significant hospital-acquired infections with Escherichia coli and Klebsiella being main players. More than 100 different ESBL types have been described, the most widespread being the CTX-M beta-lactamase enzymes (bla(CTX-M) genes). This study focuses on the zoonotic dissemination of ESBL bacteria, mainly CTX-M type, in the southern coastal region of France. We found that the level of general antibiotic resistance in single randomly selected E. coli isolates from wild Yellow-legged Gulls in France was high. Nearly half the isolates (47,1%) carried resistance to one or more antibiotics (in a panel of six antibiotics), and resistance to tetracycline, ampicillin and streptomycin was most widespread. In an ESBL selective screen, 9,4% of the gulls carried ESBL producing bacteria and notably, 6% of the gulls carried bacteria harboring CTX-M-1 group of ESBL enzymes, a recently introduced and yet the most common clinical CTX-M group in France. Multi locus sequence type and phylogenetic group designations were established for the ESBL isolates, revealing that birds and humans share E. coli populations. Several ESBL producing E. coli isolated from birds were identical to or clustered with isolates with human origin. Hence, wild birds pick up E. coli of human origin, and with human resistance traits, and may accordingly also act as an environmental reservoir and melting pot of bacterial resistance with a potential to re-infect human populations.
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| 6. |
- Brolund, Alma, et al.
(författare)
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Molecular Characterisation of Trimethoprim Resistance in Escherichia coli and Klebsiella pneumoniae during a 2 year intervention on Trimethoprim use
- 2010
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 5:2, s. e9233-
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Trimethoprim resistance is increasing in Enterobacteriaceae. In 2004-2006 an intervention on trimethoprim use was conducted in Kronoberg County, Sweden, resulting in 85% reduction in trimethoprim prescriptions. We investigated the distribution of dihydrofolate reductase (dfr)-genes and integrons in Escherichia coli and Klebsiella pneumoniae and the effect of the intervention on this distribution. METHODOLOGY/PRINCIPAL FINDINGS: Consecutively isolated E. coli (n = 320) and K. pneumoniae (n = 54) isolates phenotypically resistant to trimethoprim were studied. All were investigated for the presence of dfrA1, dfrA5, dfrA7, dfrA8, dfrA12, dfrA14, dfrA17 and integrons class I and II. Isolates negative for the seven dfr-genes (n = 12) were also screened for dfr2d, dfrA3, dfrA9, dfrA10, dfrA24 and dfrA26. These genes accounted for 96% of trimethoprim resistance in E. coli and 69% in K. pneumoniae. The most prevalent was dfrA1 in both species. This was followed by dfrA17 in E. coli which was only found in one K. pneumoniae isolate. Class I and II Integrons were more common in E. coli (85%) than in K. pneumoniae (57%). The distribution of dfr-genes did not change during the course of the 2-year intervention. CONCLUSIONS/SIGNIFICANCE: The differences observed between the studied species in terms of dfr-gene and integron prevalence indicated a low rate of dfr-gene transfer between these two species and highlighted the possible role of narrow host range plasmids in the spread of trimethoprim resistance. The stability of dfr-genes, despite large changes in the selective pressure, indirectly suggests a low fitness cost of dfr-gene carriage.
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| 7. |
- Dykes, Anna-Karin, et al.
(författare)
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Chlorhexidine for prevention of neonatal colonization with group B streptococci. II. Chlorhexidine concentrations and recovery of group B streptococci following vaginal washing in pregnant women
- 1983
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Ingår i: European Journal of Obstetrics, Gynecology, and Reproductive Biology. - : Elsevier BV. - 0301-2115. ; 16:3, s. 167-172
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Tidskriftsartikel (refereegranskat)abstract
- The effect of a single washing of the urogenital tract with 0.5 g/l chlorhexidine was studied in 6 women in weeks 38-40 of pregnancy, among whom 5 were carriers of group B streptococci in urethra and/or cervix. The chlorhexidine concentrations varied between 25 and 200 mg/l during the first hour after washing in 5 of the 6 women, whereas one patient showed concentrations below 25 mg/l. With the exception of one patient, all individuals showed concentrations less than 25 mg/l at 3-24 h after washing. A clear suppression of the number of colony-forming units of GBS was already apparent after 60 min and was still evident 6 h after chlorhexidine washing.
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| 8. |
- Froberg, Gabrielle, et al.
(författare)
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Towards clinical breakpoints for non-tuberculous mycobacteria-Determination of epidemiological cut off values for the Mycobacterium avium complex and Mycobacterium abscessus using broth microdilution
- 2023
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Ingår i: Clinical Microbiology and Infection. - : ELSEVIER SCI LTD. - 1198-743X .- 1469-0691. ; 29:6, s. 758-764
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Tidskriftsartikel (refereegranskat)abstract
- Objective: For non-tuberculous mycobacteria (NTM), minimum inhibitory concentration (MIC) distri-butions of wild-type isolates have not been systematically evaluated despite their importance for establishing antimicrobial susceptibility testing (AST) breakpoints.Methods: We gathered MIC distributions for drugs used against the Mycobacterium avium complex (MAC) and Mycobacterium abscessus (MAB) obtained by commercial broth microdilution (SLOMYCOI and RAPMYCOI) from 12 laboratories. Epidemiological cut-off values (ECOFFs) and tentative ECOFFs (TEC-OFFs) were determined by EUCAST methodology including quality control (QC) strains.Results: The clarithromycin ECOFF was 16 mg/L for M. avium (n = 1271) whereas TECOFFs were 8 mg/L for M. intracellulare (n = 415) and 1 mg/L for MAB (n = 1014) confirmed by analysing MAB subspecies without inducible macrolide resistance (n = 235). For amikacin, the ECOFFs were 64 mg/L for MAC and MAB. For moxifloxacin, the WT spanned >8 mg/L for both MAC and MAB. For linezolid, the ECOFF and TECOFF were 64 mg/L for M. avium and M. intracellulare, respectively. Current CLSI breakpoints for amikacin (16 mg/L), moxifloxacin (1 mg/L) and linezolid (8 mg/L) divided the corresponding WT dis-tributions. For QC M. avium and M. peregrinum, >= 95% of MIC values were well within recommended QC ranges.Conclusion: As a first step towards clinical breakpoints for NTM, (T)ECOFFs were defined for several antimicrobials against MAC and MAB. Broad wild-type MIC distributions indicate a need for further method refinement which is now under development within the EUCAST subcommittee for anti-mycobacterial drug susceptibility testing. In addition, we showed that several CLSI NTM breakpoints are not consistent in relation to the (T)ECOFFs. Gabrielle Froeuroberg, Clin Microbiol Infect 2023;29:758 (c) 2023 The Author(s). Published by Elsevier Ltd on behalf of European Society of Clinical Microbiology and Infectious Diseases. This is an open access article under the CC BY license (http://creativecommons. org/licenses/by/4.0/).
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