First genotypic characterization of toxigenic Clostridioides difficile in Lithuanian hospitals reveals the prevalence of the hypervirulent ribotype 027/ST1

Clostridioides difficile has become the leading nosocomial Gram-positive pathogen in the developed countries. In Lithuania, the national surveillance program for C. difficile started in 2017. Enzyme immunoassay, the real-time PCR system, and culture are used for laboratory confirmation of C. difficile infection in Lithuanian clinical laboratories. No reference laboratory for C. difficile is present in Lithuania. Fifty-eight isolates of C. difficile were collected in 2016 and 2017 in two hospitals using real-time PCR and culture methods. Agarose gel-based PCR ribotyping, multilocus variable number tandem repeats analysis (MLVA), and multilocus sequence typing (MLST) were used for the genotypic characterization of 28 isolates. PCR ribotyping and MLST showed that 78.6% of the tested toxigenic isolates belong to the ribotype RT027/ST1. Using MLVA, 95.5% of RT027 isolates were genetically related. MLVA revealed three clonal complexes in RT027. Six non-RT027 isolates showed four different electrophoretic profiles in PCR ribotyping and were assigned to the MLST sequence types ST2, ST13, ST54, and ST63. The highest discriminatory power showed the genotyping by MLVA. In total, 20 MLVA profiles were identified. This genotyping technique allowed to identify four groups of RT027/ST1 isolates that were indistinguishable by PCR ribotyping and MLST. Our study is the first genotypic characterization of C. difficile isolates in Lithuania. We observed a high prevalence of presumptive RT027 that suggests unfavorable epidemiological situation in Lithuania. Our results stress for implementation of genotyping of C. difficile isolates in Lithuanian surveillance.