| 1. |
- Helldal, Lisa
(författare)
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Epidemiology of ESBL-producing E. coli with special reference to outbreak detection
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Multidrug resistant bacteria, particularly extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae (EPE), are becoming a major health concern. ESBL-producing Escherichia coli (ESBL-E. coli) is the most prevalent type. ESBL-genes are carried on plasmids, often by bacteria belonging to clones with properties that facilitate transmission. An example is E. coli of sequence type (ST) 131, and its sublineage ST131-O25b. The most prevalent ESBLs world-wide are the CTX-M enzymes, most often belonging to the CTX-M-1 group. In Paper I the epidemiology of ESBL-E. coli causing urinary tract infection was studied from the first detected cases until these bacteria were established in the greater Gothenburg area. The first cases where seen in women from the community setting in 2003-2005. In 2008-2009, the elderly and men were also affected. The ST131-O25b sublineage became established during the study period, but otherwise the emergence of ESBL-E. coli was polyclonal. There was a shift in ESBL types in favor of the CTX-M-1 group enzymes. In Papers II and III PFGE, standard method for epidemiological typing at the time, was compared to other methods. For investigation of a polyclonal ESBL-E. coli outbreak, MLVA was found comparable to PFGE, whereas MLST-analysis was not useful. For continuous epidemiological surveillance of ESBL-E. coli, both MLVA and MLST were inferior to PFGE, especially for typing the ST131-O25b sublineage. This thesis demonstrates how the epidemiology of ESBL-E. coli might change over time, emphasising the need of continuous surveillance using optimal typing methods to detect outbreaks at the local level. We propose that an abbreviated MLVA might be useful to preselect isolates for more discriminating typing methods.
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| 2. |
- Helldal, Lisa, et al.
(författare)
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Evaluation of MLVA for epidemiological typing and outbreak detection of ESBL-producing Escherichia coli in Sweden
- 2017
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Ingår i: Bmc Microbiology. - : Springer Science and Business Media LLC. - 1471-2180. ; 17
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Tidskriftsartikel (refereegranskat)abstract
- Background: To identify the spread of nosocomial infections and halt outbreak development caused by Escherichia coli that carry multiple antibiotic resistance factors, such as extended-spectrum beta-lactamases (ESBLs) and carbapenemases, is becoming demanding challenges due to the rapid global increase and constant and increasing influx of these bacteria from the community to the hospital setting. Our aim was to assess a reliable and rapid typing protocol for ESBL-E. coli, with the primary focus to screen for possible clonal relatedness between isolates. All clinical ESBL-E. coli isolates, collected from hospitals (n = 63) and the community (n = 41), within a single geographical region over a 6 months period, were included, as well as clinical isolates from a polyclonal outbreak (ST131, n = 9, and ST1444, n = 3). The sporadic cases represented 36 STs, of which eight STs dominated i.e. ST131 (n = 33 isolates), ST648 (n = 10), ST38 (n = 9), ST12 and 69 (each n = 4), ST 167, 405 and 372 (each n = 3). The efficacy of multiple-locus variable number tandem repeat analysis (MLVA) was evaluated using three, seven or ten loci, in comparison with that of pulsed-field gel electrophoresis (PFGE) and multi locus sequence typing (MLST). Results: MLVA detected 39, 55 and 60 distinct types, respectively, using three (GECM-3), seven (GECM-7) or ten (GECM-10) loci. For GECM-7 and -10, 26 STs included one type and eleven STs each included several types, the corresponding numbers for GECM-3 were 29 and 8. The highest numbers were seen for ST131 (7,7 and 8 types, respectively), ST38 (5,5,8) and ST648 (4,5,5). Good concordance was observed with PFGE and GECM-7 and -10, despite fewer types being identified with MLVA; 78 as compared to 55 and 60 types. The lower discriminatory power of MLVA was primarily seen within the O25b-ST131 lineage (n = 34) and its H30-Rx subclone (n = 21). Epidemiologically unrelated O25b-ST131 isolates were clustered with O25b-ST131 outbreak isolates by MLVA, whereas the ST1444 outbreak isolates were accurately distinguished from unrelated isolates. Conclusion: MLVA, even when using only three loci, represents an easy initial typing tool for epidemiological screening of ESBL-E. coli. For the ST131-O25b linage, complementary methods may be needed to obtain sufficient resolution.
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| 3. |
- Helldal, Lisa, et al.
(författare)
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Increasing prevalence of ESBL but not AmpC in Escherichia coli and Klebsiella pneumoniae, in Göteborg, 2004-2008
- 2009
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Ingår i: Scandinavian Society for Antimicrobial Chemotherapy - 2009, September 3, Tromsø, Norway.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Introduction: The increasing prevalence of transferable broad-spectrum resistance to beta-lactams, such as Extended Spectrum Beta Lactamases (ESBL) and AmpC, is troublesome, since they confer resistance to cephalosporins and penicillins, and often also are associated with additional resistance. Materials and methods: Resistance for E. coli and Klebsiella pneumoniae isolated from urine (~10.000 isolates/year) and blood (~xxx isolates/year), during 2004-2008 were determined. Cephalosporin resistant isolates were examined for presence of ESBL with a double-disk-assay using clavulanic acid as inhibitory substance. Cefoxitine-resistant strains were analyzed for presence of AmpC with a second double-disk-assay using cloxacillin as inhibitory substance. Positive strains where further tested with PCR assays for ESBL and plasmid AmpC. Results: During 2004-2008 presence of ESBL increased from 0,3–1,5% in urinary and 0,0–1,4 % in blood E. coli. For Klebsiella the corresponding figures were 0,08–0,68% and 0%, respectively. For ESBL-producing E. coli, 60–80% were resistant also to quinolones and trimetoprime. In 2008, the vast a majority of the ESBL-isolates carried CTX-M subtype 1. Approximately 50 % is community-acquired isolates. 0,15-0,23% of the urinary E. coli-strains had phenotypical characteristics indicating AmpC-production. Presence of plasmid-mediated AmpC will be tested. Approximately 50% of these were multidrug resistant. In blood E coli isolates as well as in Klebsiella from urine and blood AmpC was rarely detected (0-2 isolates/year). Discussion and Conclusion: There is a steady increase in ESBL-producing bacteria in our region. However, the frequency of isolates with AmpC is still low. In addition, a majority of these strains are multidrug resistant which is particularly alarming.
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| 4. |
- Helldal, Lisa, et al.
(författare)
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Shift of CTX-M genotypes has determined the increased prevalence of extended-spectrum beta-lactamase-producing Escherichia coli in south-western Sweden
- 2013
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Ingår i: Clinical Microbiology and Infection. - : Elsevier BV. - 1198-743X .- 1469-0691. ; 19:2
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Tidskriftsartikel (refereegranskat)abstract
- The prevalence of Escherichia coli producing extended-spectrum β-lactamases (ESBLs) markedly increased during 2004-2008 in south-western Sweden, with a greater increase in urinary isolates in hospitals (0.2-2.5%) than in the community (0.2-1.6%). ESBLs of genotype CTX-M predominated, with a significant (p<0.02) shift from the CTX-M-9 to CTX-M-1 phylogroup occurring among urinary ESBL-producing E.coli isolated early (n=41) as compared with late (n=221) in the study period. The increase in ESBL-producing E.coli was polyclonal, and only partly attributable to an increase (0-24%) in the number of O25b-ST131 isolates carrying CTX-M-15. The increase was prominent in men and in elderly patients, and warrants continued surveillance.
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| 5. |
- Helldal, Lisa, et al.
(författare)
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Shifts in Extended-Spectrum Beta-Lactamase types with increasing prevalence of Escherichia coli producing ESBL
- 2010
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Ingår i: 20th European Congress of Clinical Microbiology and Infectious Diseases (ECCMID), Vienna, Austria.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Objectives: Contrary to other multidrug-resistant pathogens, the prevalence of bacteria producing extended-spectrum beta-lactamase (ESBL) is increasing rapidly in Sweden. In Europe, ESBL of CTX-M-, TEM-, OXA- and SHV-types are generally associated with E. coli infections, CTX-M being the most predominant. We have investigated how the prevalence of these types has changed during the last five years in the low endemic setting of western Sweden. Methods: Yearly resistance in urinary (approximately 10,000 isolates/year) and blood (approximately 250 isolates/year) E. coli during 2004-2008 were determined. Cephalosporin-resistant isolates were screened for ESBL, using a double-disk assay with clavulanic acid as the inhibitory agent. All ESBL-E. coli isolated in the region during the periods Sept 2003-April 2005 (n=46) and April 2008-March 2009 (n=256) were typed by multiplex-PCR, detecting CTX-M, TEM, OXA and SHV. CTX-M-positive isolates were sub-typed by real time Q-PCR for CTX-M-1, CTX-M-2 and CTXM-9 groups. Results: During 2004-2008, ESBL-producing E. coli strains increased from 0.3-1.5% in urinary and 0-1.4% in blood isolates. Resistance to quinolones and trimethoprim was observed in 60-80% of strains, as compared to less than 8% in non-ESBL-producing E. coli. The majority of the ESBL-E. coli strains possessed the CTX-M gene-type, increasing from 78% (36/46) in 2003-2005 to 93% (238/256) in 2008-2009. Between these time-periods, a marked shift occurred in the distribution of CTX-M types, in that strains with the CTX-M-9 group decreased from 42% (15/36) of isolates to 21% (51/238, p=0.01) and, simultaneously, strains with the CTX-M-1 group increased from 58% (21/36) to 78% (185/238, p= 0.02). Furthermore, strains of CTX-M-type exhibiting also TEM- and/or OXA increased to comprise 86% of cases, as compared to 75% previously. Similar trends were seen for community and hospital detected isolates and with no differences associated with age in affected patients. Conclusion: A steady increase in multidrug-resistant ESBL-E. coli, possessing the genes for multiple ESBL-types, was observed in western Sweden, contrary to the patterns of other multidrug-resistant bacteria. As ESBL has increased during the five-year study period, we detected a shift in the prevalence of ESBL-types, currently dominated by the CTX-M-1 group. These observations suggest that a novel ESBL-producing E. coli clone may have emerged in the area, which will be further investigated and presented.
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| 6. |
- Karami, Nahid, 1959, et al.
(författare)
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Investigation of an outbreak of CTX-M-15-producing Escherichia coli of sequence types 131 and 1441 in a neonatal surgical ward: comparison of typing methods
- 2010
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Ingår i: 20th European Congress of Clinical Microbiology and Infectious Diseases (ECCMID), Vienna, Austria.
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Konferensbidrag (refereegranskat)abstract
- Objectives: In a surgical ward caring mainly for newborns spread of CTX-M-15-producing E.coli had been ongoing at least since September 2008 when we finally recognized the outbreak in late December. We have compared various typing methods with pulsed-field gel electrophoresis (PFGE) to verify the actual outbreak and subsequently to determine number of affected children. Methods: In addition to clinical sampling 125 children hospitalized between Sept-Dec were screened for extended-spectrum beta-lactamase (ESBL)-producing bacteria in stool during Dec-Feb. From Jan-June 2009 newly admitted children were screened at admission and twice weekly. Fifty-one E coli isolates with ESBL from 27 children were found. These isolates have been typed with PFGE, multiple-locus-variable number tandem repeat analysis (MLVA), a mini multiple-locus-sequence typing (MLST) method (dnaJ, purA and fumC genes) as well as with the Phene Plate (PhP) biochemical fingerprinting system. Results: When the outbreak was revealed five children had developed infections with ESBL-producing E. coli that were of two PFGE-types (A and B) later considered to be the outbreak strains. One or both were spread to 21 children. Six children had multiple types. Altogether 38 isolates (20 children) were of type A (ST 131), 7 isolates (5 children) of type B (ST 1441). In addition E coli of six distinct PFGE-types (C-?) were found in one child each. MLVA gave identical discriminatory results as PFGE for all isolates tested. Mini-MLST could not differentiate ST 131 isolates of to distinct PFGE-types (type A and C) but accurately predicted the ST-types of each PFGE-type when confirmed with standard MLST according to http://mlst.ucc.ie/mlst/dbs/Ecoli. By comparing resistance pattern we thus missed the outbreak by a month. PhP indicated that all initial isolates were singletons and there was hardly any correlation with PFGE. Conclusion: If transmission has been ongoing for a long time several types of ESBL-producing bacteria may be found in an outbreak and all isolates including repeat and screening isolates need to be typed to identify affected patients. Only genetic typing, gave satisfactory results in this outbreak. MLVA gave identical results to PFGE and is thus attractive being faster, cheaper and easier to communicate. Our mini-MLST was somewhat less discriminatory but despite using only three house keeping genes accurately predicted the ST-types.
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| 7. |
- Karami, Nahid, 1959, et al.
(författare)
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Sub-Typing of Extended-Spectrum-beta-Lactamase-Producing Isolates from a Nosocomial Outbreak: Application of a 10-Loci Generic Escherichia coli Multi-Locus Variable Number Tandem Repeat Analysis
- 2013
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Ingår i: Plos One. - : Public Library of Science (PLoS). - 1932-6203. ; 8:12
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Tidskriftsartikel (refereegranskat)abstract
- Extended-spectrum beta-lactamase producing Escherichia coli (ESBL-E. coli) were isolated from infants hospitalized in a neonatal, post-surgery ward during a four-month-long nosocomial outbreak and six-month follow-up period. A multi-locus variable number tandem repeat analysis (MLVA), using 10 loci (GECM-10), for 'generic' (i.e., non-STEC) E. coli was applied for sub-species-level (i.e., sub-typing) delineation and characterization of the bacterial isolates. Ten distinct GECM-10 types were detected among 50 isolates, correlating with the types defined by pulsed-field gel electrophoresis (PFGE), which is recognized to be the 'gold-standard' method for clinical epidemiological analyses. Multi-locus sequence typing (MLST), multiplex PCR genotyping of bla(CTX-M), bla(TEM), bla(OXA) and bla(SHV) genes and antibiotic resistance profiling, as well as a PCR assay specific for detecting isolates of the pandemic O25b-ST131 strain, further characterized the outbreak isolates. Two clusters of isolates with distinct GECM-10 types (G06-04 and G07-02), corresponding to two major PFGE types and the MLST-based sequence types (STs) 131 and 1444, respectively, were confirmed to be responsible for the outbreak. The application of GECM-10 sub-typing provided reliable, rapid and cost-effective epidemiological characterizations of the ESBL-producing isolates from a nosocomial outbreak that correlated with and may be used to replace the laborious PFGE protocol for analyzing generic E. coli.
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| 8. |
- Åhrén, Christina, et al.
(författare)
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Outbreak with ESBL (CTX-M)-producing Escherichia coli in a pediatric surgical ward
- 2009
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Ingår i: Scandinavian Society for Antimicrobial Chemotherapy 2009, September 3, Tromsø, Norway.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Introduction: Nosocomial outbreaks with ESBL-producing bacteria in Scandinavia are still rare. In a surgical ward carrying mainly for small children with congenital gastrointestinal disorders spread with ESBL-producing bacteria most likely had been ongoing for three months when we detected the outbreak in December 2008. Five children with ESBL-infections had been cared for since September. Four had septicaemia as compared to no E.coli isolated in blood the previous year. Materials and methods: ESBL-detection has been performed according to routine methods. Positive isolates from patients hospitalised in the ward since 2007 were typed with pulse field gel electrophoresis (PFGE) and the PhP-phenplate method. Results: Altogether 125/169 children hospitalised during September-December were screened and 23 were positive for ESBL-producing bacteria (~50 available isolates), of which15 were only positive in stool. They had been hospitalised for a few days to several months. Four children probably constituted the infection pool. Twenty children carried the likely outbreak strain, but ESBL-producing E coli with four additional PFGE-types as well as Klebsiella pneumonie of one type were identified. Each type demonstrated up to three different resistance-patterns against trimetoprim, ciprofloxacin and tobramycin. Six children had multiple types. Discussion and Conclusion: Spread of ESBL-producing bacteria may go undetected for a long time when only clinical isolates are available. By comparing resistance pattern we missed this outbreak by more than a month. PFGE has been an invaluable tool in the investigation. Through cohorting, enforced hygiene routines, including food handling, for personnel, parents and siblings no new child has been infected (uninfected children are screened twice weekly) since the outbreak was detected.
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