Streptococcus suis in invasive human infections in Poland: clonality and determinants of virulence and antimicrobial resistance

Abstract

The purpose of this study was to perform an analysis of Streptococcus suis human invasive isolates, collected in Poland by the National Reference Centre for Bacterial Meningitis. Isolates obtained from 21 patients during 2000–2013 were investigated by phenotypic tests, multilocus sequence typing (MLST), analysis of the TR9 locus from the multilocus variable number tandem repeat (VNTR) analysis (MLVA) scheme and pulsed-field gel electrophoresis (PFGE) of SmaI-digested DNA. Determinants of virulence and antimicrobial resistance were detected by polymerase chain reaction (PCR) and analysed by sequencing. All isolates represented sequence type 1 (ST1) and were suggested to be serotype 2. PFGE and analysis of the TR9 locus allowed the discrimination of four and 17 types, respectively. Most of the isolates were haemolysis- and DNase-positive, and around half of them formed biofilm. Genes encoding suilysin, extracellular protein factor, fibronectin-binding protein, muramidase-released protein, surface antigen one, enolase, serum opacity factor and pili were ubiquitous in the studied group, while none of the isolates carried sequences characteristic for the 89K pathogenicity island. All isolates were susceptible to penicillin, cefotaxime, imipenem, moxifloxacin, chloramphenicol, rifampicin, gentamicin, linezolid, vancomycin and daptomycin. Five isolates (24 %) were concomitantly non-susceptible to erythromycin, clindamycin and tetracycline, and harboured the tet(O) and erm(B) genes; for one isolate, lsa(E) and lnu(B) were additionally detected. Streptococcus suis isolated in Poland from human invasive infections belongs to a globally distributed clonal complex of this pathogen, enriched in virulence markers. This is the first report of the lsa(E) and lnu(B) resistance genes in S. suis.Electronic supplementary materialThe online version of this article (doi:10.1007/s10096-016-2616-x) contains supplementary material, which is available to authorized users.

Streptococcus suis serotype 2 strains isolated in Argentina (South America) are different from those recovered in North America and present a higher risk for humans

“…In fact, and with this report, Argentina is now among the Western countries with the highest number of reported human cases after the Netherlands, France and the UK, with a similar number of cases to Poland (Bojarska et al , 2016). However, the three former European countries began the identification of S. suis in humans more than 15 years before Argentina, so the total number of human cases in this South American country may have been underestimated.…”

A Decennium of Etiology and Antimicrobial Susceptibility Patterns in Patients with Infective Endocarditis at a University Hospital, Thailand

“…The MIC 90 of penicillin and ceftriaxone were 0.047 and 0.125 µg/ml, respectively, which was lower than those in our study (23). The same antimicrobial susceptibility trend in invasive Streptococcus suis infection was observed in Poland and Hong Kong (24,25). A retrospective study at Chiang Mai University Hospital, Thailand from 2000 to 2002 showed that all Streptococcus suis isolates were susceptible to penicillin (mean MIC 90 = 0.028 µg/ml), whereas only 45.5% of Streptococcus suis in the present study were susceptible to penicillin, with a MIC 90 of 1.65 µg/ml (26).…”

Streptococcus suis Serotype 2 Biofilms Inhibit the Formation of Neutrophil Extracellular Traps

“…Most of SS2 human invasive isolates formed biofilm according to previous studies (Bojarska et al, 2016). Bacterial biofilm formed on host surfaces, which is critical to the virulence of these organisms.…”

“…Most of SS2 clinical isolates can form biofilms, which contribute to persistent infection, transmission and difficulties to eradicate infection (Bojarska et al, 2016). However, little information is available on the interaction between the host immune system and SS2 biofilms (Thurlow et al, 2011; Yang et al, 2016).…”