Antimicrobial susceptibilities and genomic characteristics of methicillin-resistant Staphylococcus aureus resistant to mupirocin in Stockholm, Sweden.

The aim of this study was to investigate antimicrobial susceptibilities and genomic characteristics of mupirocin-resistant MRSA isolates in Stockholm, Sweden. In total, 44 non-duplicate mupirocin-resistant MRSA isolates detected in Stockholm during 2010-2022 were investigated. Antimicrobial susceptibility testing was performed using broth microdilution method and further tested for high-level mupirocin-resistance (MuH) and rifampicin by Etest®. All isolates were subjected to whole genome sequencing. 41 isolates presented MuH with MICs ≥1024 mg/L whilst three isolates displayed low-level mupirocin resistance (MuL). mupA-gene was detected in all MuH isolates. Point mutations in ileS gene leading to N213D and V588F were identified in the three MuL isolates. Mutation in rpoB (H481N) was detected in a rifampicin-resistant isolate. Among the isolates, 15 multi-locus sequence types (MLST) were identified, with the four most common sequence types (ST22, ST72, ST8, and ST125) accounting for 66% of the isolates. Mupirocin-resistant MRSA in Stockholm was uncommon, with a percentage of <0.5% among MRSA cases during 2010-2022. In the present study, most mupirocin-resistant isolates were MuH and mupA-positive, predominantly linked to ST22 or ST72 isolates. MuL-resistance was associated with a point mutation in the IleS protein. A multidrug-resistant ST1-MRSA-IV strain was resistant to both mupirocin and rifampicin.

Antimicrobial susceptibilities and genomic epidemiology of Neisseria gonorrhoeae in Stockholm, Sweden.

The aim of this study was to investigate the genomic epidemiology and antimicrobial susceptibilities of N. gonorrhoeae isolates in Stockholm, Sweden. In total, 6723 isolates detected in Stockholm, Sweden, from January 2016 to September 2022, were examined for antimicrobial susceptibilities by using E-test. Whole-genome sequencing (WGS) was applied to isolates in sentinel surveillance and isolates resistant to extended-spectrum cephalosporins (ESCs) or high-level azithromycin (HLAzi-R, MIC ≥ 256 mg/L). As sentinel surveillance, consecutive clinical isolates (n = 396) detected every 4th week from January 2021 to September 2022 were enrolled in the study. Of the 6723 isolates investigated, 33 isolates (< 1%) were found to be resistant to cefixime, one of which was co-resistant to ceftriaxone and ciprofloxacin and was detected in September 2022. Ten isolates presented a high level of azithromycin resistance. Resistant rates to ciprofloxacin varied from 32 in 2017 to 68-69% in 2021-2022. Elevated MIC50 and MIC90 of azithromycin were observed over the years. No resistance to spectinomycin was identified. The most frequently occurring MLST in the sentinel surveillance was ST9362 (23%), followed by ST11706 (9%), ST7359 (8%), ST10314 (7%), and ST11422 (6%). The ceftriaxone-resistant isolate belonged to ST8130 and the novel NG-STAR ST4859. Genomic resistance traits found in this strain included mutations in genes mtrR (A39T), parC (S87N), and gyrA (S91F and D95A), as well as the presence of blaTEM-135 and tetM genes. A predominance of ST9362 was observed in Stockholm. The high number of azithromycin and ciprofloxacin-resistant isolates and the emergence of a strain with a novel NG-STAR are of great concern.

Multidrug-resistant Neisseria gonorrhoeae isolate SE690: mosaic penA-60.001 gene causing ceftriaxone resistance internationally has spread to the more antimicrobial-susceptible genomic lineage, Sweden, September 2022.

We report a ceftriaxone-resistant, multidrug-resistant urogenital Neisseria gonorrhoeae in a female sex worker in Sweden, September 2022, who was treated with ceftriaxone 1 g, but did not return for test-of-cure. Whole genome sequencing of isolate SE690 identified MLST ST8130, NG-STAR CC1885 (new NG-STAR ST4859) and mosaic penA-60.001. The latter, causing ceftriaxone resistance in the internationally spreading FC428 clone, has now also spread to the more antimicrobial-susceptible genomic lineage B, showing that strains across the gonococcal phylogeny can develop ceftriaxone resistance.