MALDI-TOF-massaspektrometria kliinisessä mikrobiologiassa

Kuluvan vuosikymmenen aikana MALDI-TOF-massaspektrometria (matrix-assisted laser-desorption ionization time-of-flight) on mahdollistanut taudinaiheuttajabakteerien ja -sienten tunnistamisen huomattavasti nopeammin ja luotettavammin kuin biokemiallisilla menetelmillä. Kun bakteerien tunnistus biokemiallisia menetelmiä käyttäen saattaa viedä useita vuorokausia, MALDI-TOF-massaspektrometrialla tunnistus viljelymaljalla kasvavasta pesäkkeestä voidaan tehdä muutamassa minuutissa tai positiivisesta veriviljelypullosta parissakymmenessä minuutissa. Näin kliinisen mikrobiologian laboratorio pystyy antamaan bakteeriviljelyistä tunnistustuloksen hoitavalle yksikölle heti, kun viljelymaljoilla tai veriviljelypulloissa havaitaan kasvua. MALDI-TOF-massaspektrometrian merkittävimpänä rajoituksena on se, että se vaatii edeltävän malja- tai rikastusviljelyn. Lisäksi toisilleen poikkeuksellisen läheistä sukua olevat bakteerit kuten Escherichia coli ja Shigella, jotka eivät erotu toisistaan bakteeritunnistuksessa usein referenssimenetelmänä käytetyllä 16S rRNA -sekvensoinnilla, ovat vaikeita tunnistettavia myös MALDI-TOF-massaspektrometrialla

Toisintokuume : Infektio, joka tulee huomioida maahantulijan kuumetaudin erotusdiagnostiikassa

English summaryPeer reviewe

Clinical and microbiological characterization of Aerococcus urinae bacteraemias at Helsinki metropolitan area, Finland

Our objective was to assess the incidence of bacteraemic Aerococcus urinae cases at Helsinki metropolitan area, Finland, from a 6-year study period (2013 to 2018) and to further characterize available cases. The study evaluates the outcome of commonly used cefuroxime treatment and determinate a set of A. urinae in vitro antimicrobial susceptibilities for benzylpenicillin, cefuroxime, and ceftriaxone. Clinical records of A. urinae bacteraemic patients were reviewed retrospectively. Antimicrobial susceptibility testing was performed by disk diffusion, gradient test, and broth microdilution for 139-141 clinical A. urinae isolates. Clinical data of 72/77 patients were combined with the in vitro susceptibilities. We found an increasing number of bacteraemic A. urinae cases within 6-year study period (p = 0.01). The patients were mainly elderly males, and all suffered from underlying conditions. A total of 27.3% of cases (21/77) showed polymicrobial blood cultures. Thirty-day mortality was 22.1%. Cefuroxime was the initial empiric antimicrobial agent given for 66/76 of the patients and treatment outcome was favorable for 20/22 patients who received cefuroxime at least up to day 5. All isolates were susceptible to benzylpenicillin and cefuroxime interpreted by EUCAST breakpoints for Aerococci and PK-PD breakpoints, respectively. MIC determinations gave variable results for ceftriaxone, 2.1-2.9% of the isolates were resistant. To conclude, it seems that the number of bacteraemic Aerococcus urinae cases is increasing at Helsinki metropolitan area, Finland, reflecting the growing blood culture sampling. Clinical A. urinae isolates were susceptible to cefuroxime in vitro. Treatment data indicate that empirical cefuroxime started for possibly urinary tract -derived community-acquired bacteraemia covers A. urinae.Peer reviewe

Molecular epidemiology of carbapenemase-producing Enterobacterales in Finland, 2012-2018

Carbapenemase-producing Enterobacterales (CPE) pose an increasing threat to patient safety and healthcare systems globally. We present molecular epidemiology of CPE in Finland during 2012-2018 with detailed characteristics of CPE strains causing clusters during the same time period. All Finnish clinical microbiology laboratories send Enterobacterales isolates with reduced susceptibility to carbapenems or isolates producing carbapenemase to the reference laboratory for further characterization by whole genome sequencing (WGS). In total, 231 CPE strains from 202 patients were identified during 2012-2018. Of the strains, 59% were found by screening and 32% from clinical specimens, the latter were most commonly urine. Travel and/or hospitalization history abroad was reported for 108/171 strains (63%). The most common species were Klebsiella pneumoniae (45%), Escherichia coli (40%), and Citrobacter freundii (6%), and the most common carbapenemase genes bla(NDM-like) (35%), bla(OXA-48-like) (33%), and bla(KPC-like) (31%). During 2012-2018, the annual number of CPE strains increased from 9 to 70 and different sequence types from 7 to 33, and bla(OXA-48-like) genes became the most prevalent. Of the clusters, 3/8 were linked to traveling or hospitalization abroad and 5/8 were caused by K. pneumoniae clone clonal complex 258. Most of the clusters were caused by K. pneumoniae producing KPC. High variety among different sequence types indicates that majority of CPE cases detected in Finland are likely imported from foreign countries. Nearly one-third of the cases are not found by screening suggesting that there is hidden transmission occurring in the healthcare settings.Peer reviewe

Clinical and microbiological characterization of Aerococcus urinae bacteraemias at Helsinki metropolitan area, Finland

Our objective was to assess the incidence of bacteraemic Aerococcus urinae cases at Helsinki metropolitan area, Finland, from a 6-year study period (2013 to 2018) and to further characterize available cases. The study evaluates the outcome of commonly used cefuroxime treatment and determinate a set of A. urinae in vitro antimicrobial susceptibilities for benzylpenicillin, cefuroxime, and ceftriaxone. Clinical records of A. urinae bacteraemic patients were reviewed retrospectively. Antimicrobial susceptibility testing was performed by disk diffusion, gradient test, and broth microdilution for 139-141 clinical A. urinae isolates. Clinical data of 72/77 patients were combined with the in vitro susceptibilities. We found an increasing number of bacteraemic A. urinae cases within 6-year study period (p = 0.01). The patients were mainly elderly males, and all suffered from underlying conditions. A total of 27.3% of cases (21/77) showed polymicrobial blood cultures. Thirty-day mortality was 22.1%. Cefuroxime was the initial empiric antimicrobial agent given for 66/76 of the patients and treatment outcome was favorable for 20/22 patients who received cefuroxime at least up to day 5. All isolates were susceptible to benzylpenicillin and cefuroxime interpreted by EUCAST breakpoints for Aerococci and PK-PD breakpoints, respectively. MIC determinations gave variable results for ceftriaxone, 2.1-2.9% of the isolates were resistant. To conclude, it seems that the number of bacteraemic Aerococcus urinae cases is increasing at Helsinki metropolitan area, Finland, reflecting the growing blood culture sampling. Clinical A. urinae isolates were susceptible to cefuroxime in vitro. Treatment data indicate that empirical cefuroxime started for possibly urinary tract -derived community-acquired bacteraemia covers A. urinae.</p

Molecular epidemiology of carbapenemase-producing Enterobacterales in Finland, 2012-2018

Carbapenemase-producing Enterobacterales (CPE) pose an increasing threat to patient safety and healthcare systems globally. We present molecular epidemiology of CPE in Finland during 2012-2018 with detailed characteristics of CPE strains causing clusters during the same time period. All Finnish clinical microbiology laboratories send Enterobacterales isolates with reduced susceptibility to carbapenems or isolates producing carbapenemase to the reference laboratory for further characterization by whole genome sequencing (WGS). In total, 231 CPE strains from 202 patients were identified during 2012-2018. Of the strains, 59% were found by screening and 32% from clinical specimens, the latter were most commonly urine. Travel and/or hospitalization history abroad was reported for 108/171 strains (63%). The most common species were Klebsiella pneumoniae (45%), Escherichia coli (40%), and Citrobacter freundii (6%), and the most common carbapenemase genes bla(NDM-like) (35%), bla(OXA-48-like) (33%), and bla(KPC-like) (31%). During 2012-2018, the annual number of CPE strains increased from 9 to 70 and different sequence types from 7 to 33, and bla(OXA-48-like) genes became the most prevalent. Of the clusters, 3/8 were linked to traveling or hospitalization abroad and 5/8 were caused by K. pneumoniae clone clonal complex 258. Most of the clusters were caused by K. pneumoniae producing KPC. High variety among different sequence types indicates that majority of CPE cases detected in Finland are likely imported from foreign countries. Nearly one-third of the cases are not found by screening suggesting that there is hidden transmission occurring in the healthcare settings

Outbreak of invasive pneumococcal disease among shipyard workers, Turku, Finland, May to November 2019

We report an outbreak of invasive pneumococcal disease and pneumococcal pneumonia among shipyard workers, in Turku, Southwest Finland. In total, 31 confirmed and six probable cases were identified between 3 May and 28 November 2019. Streptococcus pneumoniae serotypes 12F, 4 and 8 were isolated from blood cultures of 25 cases. Occupational hygiene measures and vaccination of ca 4,000 workers are underway to control the outbreak at the shipyard.</p

Umbilical cord blood DNA methylation in children who later develop type 1 diabetes

Abstract Aims/hypothesis: Distinct DNA methylation patterns have recently been observed to precede type 1 diabetes in whole blood collected from young children. Our aim was to determine whether perinatal DNA methylation is associated with later progression to type 1 diabetes. Methods: Reduced representation bisulphite sequencing (RRBS) analysis was performed on umbilical cord blood samples collected within the Finnish Type 1 Diabetes Prediction and Prevention (DIPP) Study. Children later diagnosed with type 1 diabetes and/or who tested positive for multiple islet autoantibodies (n = 43) were compared with control individuals (n = 79) who remained autoantibody-negative throughout the DIPP follow-up until 15 years of age. Potential confounding factors related to the pregnancy and the mother were included in the analysis. Results: No differences in the umbilical cord blood methylation patterns were observed between the cases and controls at a false discovery rate &lt;0.05. Conclusions/interpretation: Based on our results, differences between children who progress to type 1 diabetes and those who remain healthy throughout childhood are not yet present in the perinatal DNA methylome. However, we cannot exclude the possibility that such differences would be found in a larger dataset