Uusi suomalainen klamydiavariantti - haaste molekyylidiagnostiikalle

Alkuvuodesta 2019 TYKS:n mikrobiologian laboratoriossa havaittiin ristiriitaisia klamydiatestituloksia. Niiden selvittelyn tuloksena löydettiin suomalainen Chlamydia trachomatis -variantti, joka ei näkynyt laajasti käytössä olleessa klamydian ja tippurin seulontatestissä. Variantin 23S rRNA -geenin alueella todettiin yhden emäksen mutaatio. Sen vaikutusta bakteerin ­ominaisuuksiin tai kliinistä merkitystä ei vielä pystytä arvioimaan. Arviolta 6–10 % klamydiatapauksista on mutaation vuoksi jäänyt löytymättä Etelä- ja Länsi-Suomessa viime vuosina. Tosin näytteenoton puutteiden takia tapauksia saattaa jäädä toteamatta sitäkin enemmän

Nielutulehduksen pikadiagnosointi perusterveydenhuollossa

Pika- tai vieridiagnostiikalla tarkoitetaan potilaan hoitopaikassa, usein laboratorion ulkopuolella tehtäviä laboratoriotestejä, joiden tarkoitus on ohjata hoitopäätöksiä. Pikadiagnosointi on perusteltua, jos nopea tulos edistää potilaan hoitoa. Streptokokin aiheuttaman tonsilliitin ensisijainen laboratoriotesti on nielun streptokokkiviljely. Sen valmistuminen voi kuitenkin kestää niin kauan, että potilaan mikrobilääkkeestä saama hyöty vähenee merkittävästi. Mikrobilääkehoidon kohdentaminen onnistuu paremmin jollakin käytössä olevista pikadiagnostiikkamenetelmistä. Tavanomaisten liuskapikatestien lisäksi on saatavilla molekyylitestejä, joista osa sopii vieritestikäyttöön ja yksi kattaa myös C- ja G-ryhmien streptokokit.Tarkoitukseen sopivan testin valinta, testaajien koulutus ja muu laadunvarmistus edellyttävät hoitoyksikön ja laboratorion ammattilaisten yhteistyötä. Tartuntatautilain mukaan infektiotautien toteamiseksi ja torjumiseksi tehtävä potilasnäytteiden diagnosointi on luvanvaraista toimintaa.</p

The first human report of mobile colistin resistance gene, mcr-1, in Finland

Colistin resistance mediated by mobile mcr-1 gene has raised concern during the last years. After steep increase in mcr-1 reports, other mcr-gene variants (mcr-2 to mcr-5) have been revealed as well. In 2016, a clinical study was conducted on asymptomatic stool carriage of extended spectrum beta-lactamase (ESBL) producing Escherichia coli and Klebsiella pneumoniae among Finnish adults. All suspected ESBL producing bacterial isolates were first tested by phenotypic ESBL-confirmation methods, and then further analyzed with whole genome sequencing to identify the resistance genes. We found one study subject carrying a colistin resistant E.coli with a transferrable mcr-1 gene. This multi-drug resistant isolate, although initially suspected to be an ESBL producer, did not carry any ESBL genes, but was proven to carry several other resistance genes by using whole genome sequencing. Sequence type was ST93. The mcr-1 gene was connected to IncX4 plasmid which suggests that the colistin resistance gene locates in the respective plasmid. Here, we report the finding of a mcr-1 harboring human E.coli isolate from Finland. Clinical antimicrobial resistance (AMR) rates are low in Finland, and mobile colistin resistance has not been reported previously. This highlights the importance of AMR surveillance also in populations with low levels of resistance

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

The Finnish New Variant of Chlamydia trachomatis with a Single Nucleotide Polymorphism in the 23S rRNA Target Escapes Detection by the Aptima Combo 2 Test

In 2019, more than 200 cases of Chlamydia trachomatis negative/equivocal by the Aptima Combo 2 assay (AC2, target: 23S rRNA) with slightly elevated relative light units (RLUs), but positive by the Aptima Chlamydia trachomatis assay (ACT, target: 16S rRNA) have been detected in Finland To identify the cause of the AC2 CT false-negative specimens, we sequenced parts of the CT 23S rRNA gene in 40 specimens that were AC2 negative/equivocal but ACT positive. A single nucleotide polymorphism (SNP; C1515T in the C. trachomatis 23S rRNA gene) was revealed in 39 AC2/ACT discordant specimens. No decrease in the number of mandatorily notified C. trachomatis cases was observed nationally in Finland in 2010–2019. When RLUs obtained for AC2 negative specimens were retrospectively evaluated in 2011–2019, a continuous increase in the proportion of samples with RLUs 10–19 was observed since 2014, and a slight increase in the proportion of samples with RLUs 20–84 in 2017–2019, indicating that the Finnish new variant of C. trachomatis might have been spreading nationally for several years. This emphasizes that careful surveillance of epidemiology, positivity rate and test performance are mandatory to detect any changes affecting detection of infections

The Finnish New Variant of Chlamydia trachomatis with a Single Nucleotide Polymorphism in the 23S rRNA Target Escapes Detection by the Aptima Combo 2 Test

In 2019, more than 200 cases of Chlamydia trachomatis negative/equivocal by the Aptima Combo 2 assay (AC2, target: 23S rRNA) with slightly elevated relative light units (RLUs), but positive by the Aptima Chlamydia trachomatis assay (ACT, target: 16S rRNA) have been detected in Finland To identify the cause of the AC2 CT false-negative specimens, we sequenced parts of the CT 23S rRNA gene in 40 specimens that were AC2 negative/equivocal but ACT positive. A single nucleotide polymorphism (SNP; C1515T in the C. trachomatis 23S rRNA gene) was revealed in 39 AC2/ACT discordant specimens. No decrease in the number of mandatorily notified C. trachomatis cases was observed nationally in Finland in 2010–2019. When RLUs obtained for AC2 negative specimens were retrospectively evaluated in 2011–2019, a continuous increase in the proportion of samples with RLUs 10–19 was observed since 2014, and a slight increase in the proportion of samples with RLUs 20–84 in 2017–2019, indicating that the Finnish new variant of C. trachomatis might have been spreading nationally for several years. This emphasizes that careful surveillance of epidemiology, positivity rate and test performance are mandatory to detect any changes affecting detection of infections

Group A streptococcal bacteremias in Southwest Finland 2007–2018: epidemiology and role of infectious diseases consultation in antibiotic treatment selection

The incidence of invasive group A streptococcal (GAS) infections has shown a fluctuating but increasing trend in Finland. The impact of infectious diseases specialist consultation (IDSC) on the antimicrobial therapy of GAS bacteremia has not been studied earlier. A retrospective study on adult GAS bacteremia in The Hospital District of Southwest Finland (HDSWF) was conducted from 2007 to 2018. Data on incidence of bacteremic GAS cases were gathered from the National Infectious Disease Register. Clinical data were obtained by reviewing the electronic patient records. The overall incidence of GAS bacteremia in HDSWF was 3.52/100,000, but year-to-year variation was observed with the highest incidence of 7.93/100,000 in 2018. A total of 212 adult GAS bacteremia cases were included. A record of IDSC was found (+) in 117 (55.2%) cases, not found (-) in 71 (33.5%) cases and data were not available in 24 (11.3%) cases. Among IDSC+ cases, 57.3% were on penicillin G treatment whereas in the group IDSC- only 22.5%, respectively (OR = 4.61, 95% CI 2.37-8.97; p < 0.001). The use of clindamycin as adjunctive antibiotic was more common among IDSC+ (54.7%) than IDSC- (21.7%) (OR = 4.51, 95% CI 2.29-8.87; p < 0.001). There was an increasing trend in incidence of GAS bacteremia during the study period. Narrow-spectrum beta-lactam antibiotics were chosen, and adjunctive clindamycin was more commonly used, if IDSC took place. This highlights the importance of availability of IDSC but calls for improved practice among infectious diseases specialists by avoiding combination therapy with clindamycin in non-severe invasive GAS infections

Performance of the Check-Direct ESBL Screen for BD MAXTM for detection of asymptomatic faecal carriage of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli and Klebsiella pneumoniae

ObjectivesAccurte diagnostic methods are crucial for the detection of extended-spectrum β-lactamase-producing Enterobacterales (ESBL-E). Besides culture-based gold-standard methods, new molecular gene detection tests are reaching the market. The aim of this study was to investigate the performance of the direct quantitative PCR (qPCR)-based methods Check-Direct ESBL and CPE Screen for BD MAXTM in relation to traditional culture-based methods for detection of ESBL-E faecal carriage.MethodsFaecal samples were collected from healthy adult volunteers. Samples were cultured on chromogenic ESBL agar plates and were screened for ESBL-producing Escherichia coli and Klebsiella pneumoniae. Confirmed ESBL- and AmpC-producing isolates were further analysed using whole-genome sequencing. In addition, faecal samples were analysed using Check-Direct ESBL and CPE Screen for BD MAXTM and the results were compared with the gold-standard culture-based method.ResultsOf 176 faecal samples examined, 11 (6.3%) grew ESBL-producing E. coli or K. pneumoniae isolates. Among 173 analysed samples, Check-Direct ESBL Screen for BD MAXTM detected 22 (12.7%) ESBL-positive samples. No carbapenemase-producing isolates were detected. Two culture-positive samples remained negative with Check-Direct ESBL Screen for BD MAXTM. Culture-negative but qPCR-positive discrepancy was observed in 12 samples (6.9%). Altogether, concordant results were obtained for 158 samples (91.3%; 9 positive and 149 negative).ConclusionCheck-Direct ESBL Screen for BD MAXTM is a fast screening method for ESBL carriage. However, several discrepant results were observed, which hinders interpretation. More clinical samples should be tested in combination with culture to evaluate the true benefits of this method.</div