Seroprevalence of herpes simplex virus type 1 and type 2 - data from a hospital-based study in Varna, northeastern Bulgaria, 2019-2021.

The purpose of the current study was to describe the prevalence of herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) in northeastern Bulgaria. From January 2019 to December 2021, we tested 1493 samples for anti-HSV-1 IgG and 817 samples for anti-HSV-2 IgG antibodies in the Virology Laboratory, "St. Marina" University Hospital, Varna, Bulgaria. HSV-1 was considerably more widespread, with an overall seroprevalence of 73.3% (95% CI: 71.0-75.5%), than HSV-2 infection, which showed a seropositive rate of 10.0% (95% CI: 8.1-12.4%). Age was the most significant risk factor for both infections, while gender had no role in herpes simplex seropositivity.

Multicentre investigation of carbapenemase-producing Klebsiella pneumoniae and Escherichia coli in Bulgarian hospitals - Interregional spread of ST11 NDM-1-producing K. pneumoniae.

AIM: The aim of this study was to investigate the mechanisms of beta-lactam-resistance and the clonal relatedness of carbapenem-nonsusceptible Klebsiella pneumoniae and Escherichia coli isolates, collected consecutively in eight centers in five Bulgarian cities from November 2014 to March 2018. Carbapenemase-producing enterobacteria were detected in all but one centers. Overall, 104 K. pneumoniae and one E. coli were analysed. MATERIALS AND METHODS: Antimicrobial susceptibility and beta-lactamases were analysed. Conjugation experiments, plasmid fingerprinting and replicon typing, as well as MLST and ERIC-PCR were carried out. RESULTS: KPC-2 (51%) and NDM-1 (47%) were the main carbapenemases identified. KPC-2 producing K. pneumoniae were classified into 10 MLST-types. The four dominating MLST-types ST29, ST15, ST336 and ST902 comprised 79% of the KPC-2 producers. All but one of the NDM-1 producing isolates belonged to the MLST-type ST11 and were found in seven centers. Furthermore, single K. pneumoniae isolates producing VIM-1 (ST147) and OXA-48 (ST15) were identified. In addition to the carbapenemases, the ESBLs CTX-M-15, CTX-M-3, and SHV-12 as well as AmpC enzyme CMY-4 were found. The FIIAs-replicon-type was found in all KPC-2 producers while the A/C-replicons dominated in NDM-1 producing isolates. The single NDM-1 producing E. coli was determined as MLST-Type ST10 (Warwick scheme). CONCLUSION: The interregional clonal expansion of NDM-1 producing ST11 K. pneumoniae and the dissemination of blaKPC-2 carrying plasmids were responsible for the spread of carbapenemase-producing K. pneumoniae in Bulgaria. Our findings highlight the urgency to prevent dissemination of these highly transmissible and dangerous lineages.

Dissemination of successful international clone ST15 and clonal complex 17 among Bulgarian CTX-M-15 producing K. pneumoniae isolates.

A total of 82 extended spectrum beta-lactamase (ESBL) producing Klebsiella pneumoniae and 4 Klebsiella oxytoca isolates were collected in 2014 from four geographical areas in Bulgaria and their multilocus sequence type (MLST) and transferability of the ESBL encoding genes were investigated. The predominant type was CTX-M-15 (87%), followed by CTX-M-3 (9%), SHV-12 or SHV-2 (2%) and CTX-M-14 (1%). The CTX-M-15 producers belonged to ST15 (34.1%) and to a lesser extent to CC17 (ST16, ST17, ST336). The CTX-M-15 transconjugants showed a presence of R, A/C2 and F replicons. The CTX-M-3 producers were assigned to ST29, ST70, ST432, ST542 and ST15 types and the transconjugants carried M2 replicons. To the best of our knowledge, this is the first report that fully describes the MLST types among Bulgarian ESBL producing K. pneumoniae and the first report of the detection of IncR plasmid replicon type in our country.