| 1. |
- Taha, Muhamed-Kheir, et al.
(författare)
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Interlaboratory Comparison of PCR-Based Identification and Genogrouping of Neisseria meningitidis
- 2005
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Ingår i: Journal of Clinical Microbiology. - 0095-1137 .- 1098-660X. ; 43:1, s. 144-149
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Tidskriftsartikel (refereegranskat)abstract
- Twenty clinical samples (18 cerebrospinal fluid samples and 2 articular fluid samples) were sent to 11 meningococcus reference centers located in 11 different countries. Ten of these laboratories are participating in the EU-MenNet program (a European Union-funded program) and are members of the European Monitoring Group on Meningococci. The remaining laboratory was located in Burkina Faso. Neisseria meningitidis was sought by detecting several meningococcus-specific genes (crgA, ctrA, 16S rRNA, and porA). The PCR-based nonculture method for the detection of N. meningitidis gave similar results between participants with a mean sensitivity and specificity of 89.7 and 92.7%, respectively. Most of the laboratories also performed genogrouping assays (siaD and mynB/sacC). The performance of genogrouping was more variable between laboratories, with a mean sensitivity of 72.7%. Genogroup B gave the best correlation between participants, as all laboratories routinely perform this PCR. The results for genogroups A and W135 were less similar between the eight participating laboratories that performed these PCRs.
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| 2. |
- Abdeldaim, Guma M. K., et al.
(författare)
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Quantitative fucK gene polymerase chain reaction on sputum and nasopharyngeal secretions to detect Haemophilus influenzae pneumonia
- 2013
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Ingår i: Diagnostic microbiology and infectious disease. - : Elsevier. - 0732-8893 .- 1879-0070. ; 76:2, s. 141-146
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Tidskriftsartikel (refereegranskat)abstract
- A quantitative polymerase chain reaction (PCR) for the fucK gene was developed for specific detection of Haemophilus influenzae. The method was tested on sputum and nasopharyngeal aspirate (NPA) from 78 patients with community-acquired pneumonia (CAP). With a reference standard of sputum culture and/or serology against the patient's own nasopharyngeal isolate, H. influenzae etiology was detected in 20 patients. Compared with the reference standard, fucK PCR (using the detection limit 10(5) DNA copies/mL) on sputum and NPA showed a sensitivity of 95.0% (19/20) in both cases, and specificities of 87.9% (51/58) and 89.5% (52/58), respectively. In a receiver operating characteristic curve analysis, sputum fucK PCR was found to be significantly superior to sputum P6 PCR for detection of H. influenzae CAP. NPA fucK PCR was positive in 3 of 54 adult controls without respiratory symptoms. In conclusion, quantitative fucK real-time PCR provides a sensitive and specific identification of H. influenzae in respiratory secretions.
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| 3. |
- Abdeldaim, Guma, et al.
(författare)
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Usefulness of real-time PCR for lytA, ply, and Spn9802 on plasma samples for the diagnosis of pneumococcal pneumonia
- 2010
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Ingår i: Clinical Microbiology and Infection. - : Elsevier BV. - 1198-743X .- 1469-0691. ; 16:8, s. 1135-1141
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Tidskriftsartikel (refereegranskat)abstract
- In the present study, we evaluated rapid real-time PCR assays for ply, Spn9802, and lytA applied to plasma samples for the detection of Streptococcus pneumoniae in patients with community-acquired pneumonia (CAP). In a prospective study of CAP aetiology, an EDTA plasma sample was collected together with blood culture in 92 adult CAP patients and 91 adult controls. Among the 92 CAP patients, lytA PCR was positive in eight (9%), Spn9802 PCR was positive in 11 (12%) and ply PCR was positive in 19 (21%) cases. Of 91 controls, the ply PCR was positive in eight cases (9%), but no positive cases were noted by Spn9802 or lytA PCRs. Ten CAP patients had pneumococcal bacteraemia. Compared to blood culture, PCR for lytA, Spn9802 and ply had sensitivities of 70% (7/10), 60% (6/10) and 70% (7/10), and specificities of 96% (79/82), 94% (77/82) and 85% (70/82) respectively. With blood culture and/or culture of representative sputum, and/or urinary antigen detection, S. pneumoniae was identified in 31 CAP patients. Compared to these tests in combination, PCR for lytA, Spn9802 and ply showed sensitivities of 26% (8/31), 32% (10/31) and 42% (13/31), and specificities of 100% (61/61), 98% (60/61) and 90% (55/61) respectively. We conclude that Spn9802 and lytA PCRs may be useful for the rapid detection of bacteraemic pneumococcal pneumonia, whereas ply PCR is not specific enough for routine use and blood PCR with small plasma volumes is not useful for the detection of nonbacteraemic pneumococcal pneumonia.
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| 4. |
- Ahlstrand, Erik, 1974-, et al.
(författare)
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Evaluation of a PCR method to determine the clinical significance of blood cultures with Staphylococcus epidermidis in patients with hematological malignancies
- 2014
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Ingår i: Acta Pathologica, Microbiologica et Immunologica Scandinavica (APMIS). - : Wiley-Blackwell. - 0903-4641 .- 1600-0463. ; 122:6, s. 539-544
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Tidskriftsartikel (refereegranskat)abstract
- The aim was to investigate whether the detection and quantification of Staphylococcus epidermidis DNA in blood could distinguish S. epidermidis blood stream infections (BSIs) from blood culture contaminations in patients with hematological malignancies. The hld gene was chosen to identify S. epidermidis DNA and DNA in blood samples was detected by real-time PCR. Blood samples were obtained simultaneously with blood cultures positive for S. epidermidis (n = 30), during blood culture-negative episodes (n = 10) and episodes of bacteremia with other bacteria than S. epidermidis (n = 4) and from healthy blood donors (n = 10). In addition, DNA from S. epidermidis and a selection of other bacterial species were analyzed. Three different sets of criteria were used to classify episodes with positive blood cultures with S. epidermidis as BSIs or contaminations. All DNA preparations from S. epidermidis (n = 48) were hld-positive, but other bacterial species (n = 13) were negative. Sixteen (53%) of 30 blood samples from patients with blood cultures positive for S. epidermidis were hld-positive, but none of the controls. There was no clear association between a positive hld PCR and episodes interpreted as BSIs. In conclusion, hld PCR failed to distinguish S. epidermidis BSIs from blood culture contaminations in patients with hematological malignancies.
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| 5. |
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| 6. |
- Berglund, Carolina, et al.
(författare)
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Multilocus sequence typing of methicillin-resistant Staphylococcus aureus from an area of low endemicity by real-time PCR
- 2005
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Ingår i: Journal of clinical microbiology. ; 43:9, s. 4448-4454
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Tidskriftsartikel (refereegranskat)abstract
- A protocol for multilocus sequence typing (MLST) of methicillin-resistant Staphylococcus aureus (MRSA) was adapted to real-time LightCycler System PCR for efficient and rapid amplification of seven housekeeping genes in the same PCR run and real-time detection of the products. The method was evaluated on a representative and well-characterized collection of clinical MRSA isolates (n = 57) obtained from an area of low endemicity. Twenty sequence types (STs) and nine clonal complexes were identified. Combining STs and the staphylococcal cassette chromosome mec (SCCmec) type identified 27 different genotypes, and type IV SCCmec was present in 11 different STs. The presence of the Panton Valentine leukocidin (PVL) genes was found in isolates of four different STs. Eleven different STs were found among the community-acquired as well as among the hospital-acquired MRSA. The genetic heterogeneity was also denoted by pulsed-field gel electrophoresis analysis that showed 24 different pulsotypes among the 57 MRSA isolates. The presence of more than one different type of SCCmec in the same ST indicates that the MRSA clones have arisen at several occasions in the same genetic background by independent acquisition of SCCmec into methicillin-sensitive strains. This circumstance shows the importance of combining MLST data with SCCmec-typing results when investigating the origins of MRSA.
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| 7. |
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| 8. |
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| 9. |
- Campillay Lagos, Amaya, 1989-, et al.
(författare)
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Evaluation of within-host evolution of methicillin-resistant Staphylococcus aureus (MRSA) by comparing cgMLST and SNP analysis approaches
- 2022
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Ingår i: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- Whole genome sequencing (WGS) of methicillin-resistant Staphylococcus aureus (MRSA) provides high-resolution typing, facilitating surveillance and outbreak investigations. The aim of this study was to evaluate the genomic variation rate in MRSA, by comparing commonly used core genome multilocus sequencing (cgMLST) against single nucleotide polymorphism (SNP) analyses. WGS was performed on 95 MRSA isolates, collected from 20 carriers during years 2003-2019. To assess variation and methodological-related differences, two different cgMLST schemes were obtained using Ridom SeqSphere+ and the cloud-based 1928 platform. In addition, two SNP methods, 1928 platform and Northern Arizona SNP Pipeline (NASP) were used. The cgMLST using Ridom SeqSphere+ and 1928 showed a median of 5.0 and 2.0 allele variants/year, respectively. In the SNP analysis, performed with two reference genomes COL and Newman, 1928 showed a median of 13 and 24 SNPs (including presumed recombination) and 3.8 respectively 4.0 SNPs (without recombination) per individual/year. Accordantly, NASP showed a median of 5.5 and 5.8 SNPs per individual/year. In conclusion, an estimated genomic variation rate of 2.0-5.8 genetic events per year (without recombination), is suggested as a general guideline to be used at clinical laboratories for surveillance and outbreak investigations independently of analysis approach used.
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| 10. |
- Clarke, S. C., et al.
(författare)
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Analysis of PorA variable region 3 in meningococci : implications for vaccine policy?
- 2003
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Ingår i: Vaccine. - 0264-410X .- 1873-2518. ; 21:19-20, s. 2468-2473
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Tidskriftsartikel (refereegranskat)abstract
- Outer membrane protein (OMP) vaccines are being developed against Neisseria meningitidis serogroup B which may provide protection against common circulating serotypes and serosubtypes in some countries. However, limited data is available in Europe from genosubtyping meningococci. We therefore undertook a retrospective analysis of the three main variable regions, VR1, VR2 as well as VR3, of the porA gene from N. meningitidis isolated from different countries, mainly from Scotland and Sweden. Analysis of this gene showed that, amongst 226 strains studied, there were a total of 78 different strains. No new VR1 or VR2 alleles were found but five new VR3 alleles are described. Our data indicates the importance of analysing the VR3 region of PorA in addition to VR1 and VR2 and also highlights, in general terms, the need for genosubtyping meningococci. Such analyses have major implications for the design of new meningococcal vaccines.
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| 11. |
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| 12. |
- Davidsson, Sabina, 1972-, et al.
(författare)
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Frequency and typing of Propionibacterium acnes in prostate tissue obtained from men with and without prostate cancer
- 2016
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Ingår i: Infectious Agents and Cancer. - London, United Kingdom : BioMed Central (BMC). - 1750-9378. ; 11
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Tidskriftsartikel (refereegranskat)abstract
- Background: Prostate cancer is the most common cancer among men in Western countries but the exact pathogenic mechanism of the disease is still largely unknown. An infectious etiology and infection-induced inflammation has been suggested to play a role in prostate carcinogenesis and Propionibacterium acnes has been reported as the most prevalent microorganism in prostatic tissue. We investigated the frequency and types of P. acnes isolated from prostate tissue samples from men with prostate cancer and from control patients without the disease.Methods: We included 100 cases and 50 controls in this study. Cases were men diagnosed with prostate cancer undergoing radical prostatectomy and controls were men undergoing surgery for bladder cancer without any histological findings of prostate cancer. Six biopsies taken from each patient's prostate gland at the time of surgery were used for cultivation and further characterization of P. acnes.Results: The results revealed that P. acnes was more common in men with prostate carcinoma than in controls, with the bacteria cultured in 60 % of the cases vs. 26 % of the controls (p = 0.001). In multivariable analyses, men with P. acnes had a 4-fold increase in odds of a prostate cancer diagnosis after adjustment for age, calendar year of surgery and smoking status (OR: 4.46; 95 % CI: 1.93-11.26). To further support the biologic plausibility for a P. acnes infection as a contributing factor in prostate cancer development, we subsequently conducted cell-based experiments. P. acnes- isolates were co-cultured with the prostate cell line PNT1A. An increased cell proliferation and cytokine/chemokine secretion in infected cells was observed.Conclusion: The present study provides further evidence for a role of P. acnes in prostate cancer development.
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| 13. |
- Davidsson, Sabina, 1972-, et al.
(författare)
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Multilocus sequence typing and repetitive-sequence-based PCR (DiversiLab) for molecular epidemiological characterization of Propionibacterium acnes isolates of heterogeneous origin
- 2012
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Ingår i: Anaerobe. - : Elsevier. - 1075-9964 .- 1095-8274. ; 18:4, s. 392-399
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Tidskriftsartikel (refereegranskat)abstract
- Propionibacterium acnes is a gram-positive bacillus predominantly found on the skin. Although it is considered an opportunistic pathogen it is also been associated with severe infections. Some specific P. acnes subtypes are hypothesized to be more prone to cause infection than others. Thus, the aim of the present study was to investigate the ability to discriminate between P. acnes isolates of a refined multilocus sequence typing (MLST) method and a genotyping method, DiversiLab, based on repetitive-sequence-PCR technology.The MLST and DiversiLab analysis were performed on 29 P. acnes isolates of diverse origins; orthopedic implant infections, deep infections following cardiothoracic surgery, skin, and isolates from perioperative tissue samples from prostate cancer. Subtyping was based on recA, tly, and Tc12S sequences.The MLST analysis identified 23 sequence types and displayed a superior ability to discriminate P. acnes isolates compared to DiversiLab and the subtyping. The highest discriminatory index was found when using seven genes. DiversiLab was better able to differentiate the isolates compared to the MLST clonal complexes of sequence types.Our results suggest that DiversiLab can be useful as a rapid typing tool for initial discrimination of P. acnes isolates. When better discrimination is required, such as for investigations of the heterogeneity of P. acnes isolates and its involvement in different pathogenic processes, the present MLST protocol is valuable.
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| 14. |
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| 15. |
- Davidsson, Sabina, 1972-, et al.
(författare)
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Prevalence of Flp Pili-Encoding Plasmids in Cutibacterium acnes Isolates Obtained from Prostatic Tissue
- 2017
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Ingår i: Frontiers in Microbiology. - : Frontiers Media S.A.. - 1664-302X. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- Inflammation is one of the hallmarks of prostate cancer. The origin of inflammation is unknown, but microbial infections are suspected to play a role. In previous studies, the Gram-positive, low virulent bacterium Cutibacterium (formerly Propionibacterium) acnes was frequently isolated from prostatic tissue. It is unclear if the presence of the bacterium represents a true infection or a contamination. Here we investigated Cutibacterium acnes type II, also called subspecies defendens, which is the most prevalent type among prostatic C. acnes isolates. Genome sequencing of type II isolates identified large plasmids in several genomes. The plasmids are highly similar to previously identified linear plasmids of type I C. acnes strains associated with acne vulgaris. A PCR-based analysis revealed that 28.4% (21 out of 74) of all type II strains isolated from cancerous prostates carry a plasmid. The plasmid shows signatures for conjugative transfer. In addition, it contains a gene locus for tight adherence (tad) that is predicted to encode adhesive Flp (fimbrial low-molecular weight protein) pili. In subsequent experiments a tad locus-encoded putative pilin subunit was identified in the surface-exposed protein fraction of plasmid-positive C. acnes type II strains by mass spectrometry, indicating that the tad locus is functional. Additional plasmid-encoded proteins were detected in the secreted protein fraction, including two signal peptide-harboring proteins; the corresponding genes are specific for type II C. acnes, thus lacking from plasmid-positive type I C. acnes strains. Further support for the presence of Flp pili in C. acnes type II was provided by electron microscopy, revealing cell appendages in tad locus-positive strains. Our study provides new insight in the most prevalent prostatic subspecies of C. acnes, subsp. defendens, and indicates the existence of Flp pili in plasmid-positive strains. Such pili may support colonization and persistent infection of human prostates by C. acnes.
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| 16. |
- Edsjö, Anders, et al.
(författare)
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Building a precision medicine infrastructure at a national level : The Swedish experience
- 2023
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Ingår i: Cambridge Prisms: Precision Medicine. - : Cambridge University Press. - 2752-6143. ; 1
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Forskningsöversikt (refereegranskat)abstract
- Precision medicine has the potential to transform healthcare by moving from one-size-fits-all to personalised treatment and care. This transition has been greatly facilitated through new high-throughput sequencing technologies that can provide the unique molecular profile of each individual patient, along with the rapid development of targeted therapies directed to the Achilles heels of each disease. To implement precision medicine approaches in healthcare, many countries have adopted national strategies and initiated genomic/precision medicine initiatives to provide equal access to all citizens. In other countries, such as Sweden, this has proven more difficult due to regionally organised healthcare. Using a bottom-up approach, key stakeholders from academia, healthcare, industry and patient organisations joined forces and formed Genomic Medicine Sweden (GMS), a national infrastructure for the implementation of precision medicine across the country. To achieve this, Genomic Medicine Centres have been established to provide regionally distributed genomic services, and a national informatics infrastructure has been built to allow secure data handling and sharing. GMS has a broad scope focusing on rare diseases, cancer, pharmacogenomics, infectious diseases and complex diseases, while also providing expertise in informatics, ethical and legal issues, health economy, industry collaboration and education. In this review, we summarise our experience in building a national infrastructure for precision medicine. We also provide key examples how precision medicine already has been successfully implemented within our focus areas. Finally, we bring up challenges and opportunities associated with precision medicine implementation, the importance of international collaboration, as well as the future perspective in the field of precision medicine.
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| 17. |
- Eriksson, Lorraine, 1990-, et al.
(författare)
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Difference in virulence between Neisseria meningitidis serogroups W and Y in transgenic mice
- 2020
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Ingår i: BMC Microbiology. - : BioMed Central. - 1471-2180. ; 20:1
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Neisseria meningitidis serogroups W and Y are the most common serogroups causing invasive meningococcal disease in Sweden. The majority of cases are caused by the serogroup W UK 2013 strain of clonal complex (cc) 11, and subtype 1 of the serogroup Y, YI strain of cc23. In this study, virulence factors of several lineages within cc11 and cc23 were investigated in transgenic BALB/c mice expressing human transferrin. Transgenic mice were infected intraperitoneally with serogroup W and Y isolates. Levels of bacteria and the proinflammatory cytokine CXCL1 were determined in blood collected 3 h and 24 h post-infection. Apoptosis was investigated in immune cells from peritoneal washes of infected mice. Adhesion and induction of apoptosis in human epithelial cells were also scored.RESULTS: The levels of bacteraemia, CXCL1, and apoptosis were higher in serogroup W infected mice than in serogroup Y infected mice. Serogroup W isolates also induced higher levels of apoptosis and adhesion in human epithelial cells. No significant differences were observed between different lineages within cc11 and cc23.CONCLUSIONS: N. meningitidis Serogroup W displayed a higher virulence in vivo in transgenic mice, compared to serogroup Y. This was reflected by higher bacteremia, proinflammatory activity, and ability to induce apoptosis in mouse immune cells and human epithelial cells.
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| 18. |
- Eriksson, Lorraine, 1990-
(författare)
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Exploring genomic and phenotypic differences in Neisseria meningitidis : understanding carriage and invasive disease
- 2024
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Neisseria meningitidis can colonise the nasopharynx in humans and is also the cause of invasive meningococcal disease (IMD), which often presents as septicaemia and meningitis with high mortality rates. Invasive disease is often associated with specific capsular serogroups and clonal complexes (CC). In Sweden, serogroups Y and W have had a high incidence in recent years, but were previously considered rare causes of IMD, suggesting a change in the virulence potential of these serogroups. Currently, no specific genes exist that can reliably predict whether an N. meningitidis isolate will result in invasive disease or remain in the carriage state. Genetically similar isolates can be found during carriage and IMD, and it is more common for the carriage isolates to lack a capsule. The aim of this thesis was to investigate how genetic and phenotypic differences in N. meningitidis, can affect the virulence and the transition from a carriage state to invasive disease.The results indicate that the increase of serogroup W in Sweden is due to a specific lineage of CC11. This CC is rarely found among carriers and is considered highly virulent. Infections in transgenic mice with serogroup W CC11 isolates showed a greater virulence compared to serogroup Y isolates from other CCs. Although both serogroups are common causes of IMD in Sweden, they differ in virulence in transgenic mice. A genome-wide association study comparing carriage and invasive isolates, revealed that there were genetic variants in genes associated with virulence between these isolates. Among these variants were pilE/pilS, which are involved in the type IV pili. Comparison of pilE gene expression between carriage and invasive isolates showed no significant difference between these isolates. However, a difference in the class of the PilE protein was found between invasive and carriage isolates. Further research is needed to understand the impact of these genetic variations on the transition from carriage to invasive disease, also considering how factors in the human host and the environment that may contribute to the development of invasive disease.
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| 19. |
- Eriksson, Lorraine, 1990-, et al.
(författare)
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Genetic variants linked to the phenotypic outcome of invasive disease and carriage of Neisseria meningitidis
- 2023
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Ingår i: Microbial Genomics. - : Microbiology Society. - 2057-5858. ; 9:10
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Tidskriftsartikel (refereegranskat)abstract
- Neisseria meningitidis can be a human commensal in the upper respiratory tract but is also capable of causing invasive diseases such as meningococcal meningitis and septicaemia. No specific genetic markers have been detected to distinguish carriage from disease isolates. The aim here was to find genetic traits that could be linked to phenotypic outcomes associated with carriage versus invasive N. meningitidis disease through a bacterial genome-wide association study (GWAS). In this study, invasive N. meningitidis isolates collected in Sweden (n=103) and carriage isolates collected at Örebro University, Sweden (n=213) 2018-2019 were analysed. The GWAS analysis, treeWAS, was applied to single-nucleotide polymorphisms (SNPs), genes and k-mers. One gene and one non-synonymous SNP were associated with invasive disease and seven genes and one non-synonymous SNP were associated with carriage isolates. The gene associated with invasive disease encodes a phage transposase (NEIS1048), and the associated invasive SNP glmU S373C encodes the enzyme N-acetylglucosamine 1-phosphate (GlcNAC 1-P) uridyltransferase. Of the genes associated with carriage isolates, a gene variant of porB encoding PorB class 3, the genes pilE/pilS and tspB have known functions. The SNP associated with carriage was fkbp D33N, encoding a FK506-binding protein (FKBP). K-mers from PilS, tbpB and tspB were found to be associated with carriage, while k-mers from mtrD and tbpA were associated with invasiveness. In the genes fkbp, glmU, PilC and pilE, k-mers were found that were associated with both carriage and invasive isolates, indicating that specific variations within these genes could play a role in invasiveness. The data presented here highlight genetic traits that are significantly associated with invasive or carriage N. meningitidis across the species population. These traits could prove essential to our understanding of the pathogenicity of N. meningitidis and could help to identify future vaccine targets.
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| 20. |
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| 21. |
- Eriksson, Lorraine, 1990-, et al.
(författare)
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Whole-Genome Sequencing of Emerging Invasive Neisseria meningitidis Serogroup W in Sweden
- 2018
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Ingår i: Journal of Clinical Microbiology. - : American Society for Microbiology. - 0095-1137 .- 1098-660X. ; 56:4
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Tidskriftsartikel (refereegranskat)abstract
- Invasive disease caused by Neisseria meningitidis serogroup W (MenW) has historically had a low incidence in Sweden, with an average incidence of 0.03 case/100,000 population from 1995 to 2014. In recent years, a significant increase in the incidence of MenW has been noted in Sweden, to an average incidence of 0.15 case/100,000 population in 2015 to 2016. In 2017 (1 January to 30 June), 33% of invasive meningococcal disease cases (7/21 cases) were caused by MenW. In the present study, all invasive MenW isolates from Sweden collected in 1995 to June 2017 (n = 86) were subjected to whole-genome sequencing to determine the population structure and to compare isolates from Sweden with historical and international cases. The increase of MenW in Sweden was determined to be due to isolates belonging to the South American sublineage of MenW clonal complex 11, namely, the novel U.K. 2013 lineage. This lineage was introduced in Sweden in 2013 and has since been the dominant lineage of MenW.
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| 22. |
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| 23. |
- Fagerström, Anna, 1980-, et al.
(författare)
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Comparative distribution of extended-spectrum beta-lactamase-producing Escherichia coli from urine infections and environmental waters
- 2019
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Ingår i: PLOS ONE. - : PLOS. - 1932-6203. ; 14:11
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Tidskriftsartikel (refereegranskat)abstract
- Extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli have been reported in natural environments, and may be released through wastewater. In this study, the genetic relationship between ESBL-producing E. coli collected from patient urine samples (n = 45, both hospitalized patients and out-patients) and from environmental water (n = 82, from five locations), during the same time period, was investigated. Three independent water samples were collected from the municipal wastewater treatment plant, both incoming water and treated effluent water; the receiving river and lake; and a bird sanctuary near the lake, on two different occasions. The water was filtered and cultured on selective chromID ESBL agar plates in order to detect and isolate ESBL-producing E. coli. Illumina whole genome sequencing was performed on all bacterial isolates (n = 127). Phylogenetic group B2 was more common among the clinical isolates than the environmental isolates (44.4% vs. 17.1%, p < 0.01) due to a significantly higher prevalence of sequence type (ST) 131 (33.3% vs. 13.4%, p < 0.01). ST131 was, however, one of the most prevalent STs among the environmental isolates. There was no significant difference in diversity between the clinical isolates (DI 0.872 (0.790-0.953)) and the environmental isolates (DI 0.947 (0.920-0.969)). The distribution of ESBL genes was similar: blaCTX-M-15 dominated, followed by blaCTX-M-14 and blaCTX-M-27 in both the clinical (60.0%, 8.9%, and 6.7%) and the environmental isolates (62.2%, 12.2%, and 8.5%). Core genome multi-locus sequence typing showed that five environmental isolates, from incoming wastewater, treated wastewater, Svartån river and Hjälmaren lake, were indistinguishable or closely related (≤10 allele differences) to clinical isolates. Isolates of ST131, serotype O25:H4 and fimtype H30, from the environment were as closely related to the clinical isolates as the isolates from different patients were. This study confirms that ESBL-producing E. coli are common in the aquatic environment even in low-endemic regions and suggests that wastewater discharge is an important route for the release of ESBL-producing E. coli into the aquatic environment.
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| 24. |
- Fagerström, Anna, 1980-
(författare)
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Long-term molecular epidemiology of extended-spectrum β-lactamase producing Escherichia coli in a low-endemic setting
- 2020
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Escherichia coli is a commensal inhabitant in the gastro-intestinal tract of humans and animals but it is also the most common bacterial species causing urinary tract infection, which ranges in severity from distal cystitis to urosepsis and septic shock. During the past decades, the prevalence of antibiotic resistant E. coli has increased worldwide. Extended-spectrum β-lactamases (ESBL) causes resistance to β-lactam antibiotics, the most widely used class of antibiotics. The genes encoding ESBL, bla, are usually carried on conjugative plasmids, which can be transferred between different bacterial lineages and different species. These plasmids frequently also carry resistance genes to additional antibiotic classes, and ESBL-producing E. coli are therefore often multidrug-resistant. The aim of this thesis was to describe the long-term molecular epidemiology of ESBL-producing E. coli in Örebro County during the time when they first started to emerge. In addition, potential transmission to the environment was investigated by performing a comparative analysis on ESBL-producing E. coli isolated from patients and from the aquatic environment in Örebro city. In general, the E. coli population was genetically diverse, but the pandemic lineage ST131, first identified in 2004, appears to have been responsible for the dramatic increase of CTX-M-15-producing E.coli observed during the late 2000s. CTX-M-15 was the most prevalent ESBL-type followed by CTX-M-14 and these genes were mainly found on plasmids belonging to the IncF or IncI1 families. Continuous horizontal transmission of IncI1 ST31 and ST37 plasmids between diverse E. coli lineages have also contributed to the dissemination of blaCTX-M-15 in Örebro County. Extended spectrum β-lactamase-producing E. coli were found to be common in the aquatic environment in Örebro city and E. coli lineages genetically similar to those causing infections in humans were present in environmental waters indicating that transmission of ESBL-producing E. colifrom humans to the aquatic environment likely has occurred.
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| 25. |
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