Three Cases of Tickborne Francisella tularensis Infection, Austria, 2022.

Tularemia is increasing in Austria. We report Francisella tularensis subspecies holarctica isolated from 3 patients who had been bitten by arthropods. Next-generation sequencing showed substantial isolate similarity. Clinicians should consider bloodstream F. tularensis infections for patients with signs/symptoms of ulceroglandular tularemia, and surveillance of potential vectors should be intensified.

First report on the occurrence of Vibrio cholerae nonO1/nonO139 in natural and artificial lakes and ponds in Serbia: Evidence for a long-distance transfer of strains and the presence of Vibrio paracholerae.

Vibrio cholerae are natural inhabitants of specific aquatic environments. Strains not belonging to serogroups O1 and O139 are usually unable to produce cholera toxin and cause cholera. However, non-toxigenic V. cholerae (NTVC) are able to cause a variety of mild-to-severe human infections (via seafood consumption or recreational activities). The number of unreported cases is considered substantial, as NTVC infections are not notifiable and physicians are mostly unaware of this pathogen. In the northern hemisphere, NTVC infections have been reported to increase due to global warming. In Eastern Europe, climatic and geological conditions favour the existence of inland water-bodies harbouring NTVC. We thus investigated the occurrence of NTVC in nine Serbian natural and artificial lakes and ponds, many of them used for fishing and bathing. With the exception of one highly saline lake, all investigated water-bodies harboured NTVC, ranging from 5.4 × 101 to 1.86 × 104  CFU and 4.5 × 102 to 5.6 × 106 genomic units per 100 ml. The maximum values observed were in the range of bathing waters in other countries, where infections have been reported. Interestingly, 7 out of 39 fully sequenced presumptive V. cholerae isolates were assigned as V. paracholerae, a recently described sister species of V. cholerae. Some clones and sublineages of both V. cholerae and V. paracholerae were shared by different environments indicating an exchange of strains over long distances. Important pathogenicity factors such as hlyA, toxR, and ompU were present in both species. Seasonal monitoring of ponds/lakes used for recreation in Serbia is thus recommended to be prepared for potential occurrence of infections promoted by climate change-induced rise in water temperatures.

Resistance profiles of Neisseria gonorrhoeae isolates in Vienna, Austria: a phenotypic and genetic characterization from 2013 to 2020.

OBJECTIVES: International surveillance data show a constant rise in the number of Neisseria gonorrhoeae infections and an increase in drug resistance of N. gonorrhoeae. As recent N. gonorrhoeae surveillance data in Austria are scarce, this study investigated phenotypic and genotypic antimicrobial resistance in N. gonorrhoeae isolates. METHODS: In total, 440 N. gonorrhoeae samples were collected at the Medical University of Vienna, and the minimal inhibitory concentrations (MICs) for a range of different antibiotics were determined. Sampling sites and treatments were recorded, and whole-genome sequencing of N. gonorrhoeae isolates was performed using allele libraries to determine genotypic resistance. RESULTS: The median MICs for ceftriaxone, cefixime, azithromycin, ciprofloxacin, tetracycline and penicillin were <0.002 µg/mL, <0.016 µg/mL, 0.25 µg/mL, 2.0 µg/mL, 1.5 µg/mL and 0.25 µg/mL, respectively. Annual comparison showed that MICs were generally stable for all antimicrobial agents except azithromycin, for which an increase in median MIC was observed from 2017 (0.25 µg/mL). There was no genetic resistance to ceftriaxone; 8% of samples displayed resistance mutations against cefixime, primarily located in the penA gene. Resistance to azithromycin increased from 2% in 2013 to 12% in 2020. MtrD mosaic had the highest impact on azithromycin susceptibility; 47% of the resistant isolates showed this mutation. The majority of cases of gonorrhoea were treated successfully with either ceftriaxone or a ceftriaxone/azithromycin regime. Two treatment failures occurred under monotherapy with doxycycline. Overall, genotypic resistance corresponded significantly to all respective MICs. CONCLUSIONS: The resistance rate of N. gonorrhoeae to antibiotics has remained stable in Vienna over the last decade, except for azithromycin. The strong correlation found between genetic and phenotypic patterns in this study holds promise for future diagnostics of N. gonorrhoeae resistance based on genotypes.

Association of Phylogenomic Relatedness among Neisseria gonorrhoeae Strains with Antimicrobial Resistance, Austria, 2016-2020.

We investigated genomic determinants of antimicrobial resistance in 1,318 Neisseria gonorrhoeae strains isolated in Austria during 2016-2020. Sequence type (ST) 9363 and ST11422 isolates had high rates of azithromycin resistance, and ST7363 isolates correlated with cephalosporin resistance. These results underline the benefit of genomic surveillance for antimicrobial resistance monitoring.

Rifampicin Resistance Associated with rpoB Mutations in Neisseria gonorrhoeae Clinical Strains Isolated in Austria, 2016 to 2020.

Due to increasing rates of antimicrobial resistance (AMR) in Neisseria gonorrhoeae, alternative treatments should be considered. To assess rifampicin's potential as a gonorrhea treatment, we used rpoB mutations to estimate rifampicin resistance in Austrian N. gonorrhoeae isolates. We found 30% of resistant isolates clustering in three main phylogenomic branches. Rifampicin resistance was associated with resistance to other antibiotics. Therefore, rifampicin cannot be recommended as an alternative gonorrhea treatment in Austria, even in combination therapy. IMPORTANCE Gonorrhea, caused by Neisseria gonorrhoeae, is one of the most common bacterial sexually transmitted infections. It is treated with antibiotics, but an increasing number of N. gonorrhoeae strains are resistant to currently used treatments. In this study, we explored the potential of rifampicin, another antibiotic, as a treatment option for gonorrhea. However, around 30% of Austrian N. gonorrhoeae strains investigated were already resistant to rifampicin, which would limit its benefit as a gonorrhea treatment.

Improved group-specific primers based on the full SILVA 16S rRNA gene reference database.

Quantitative PCR (qPCR) and community fingerprinting methods, such as the Terminal Restriction Fragment Length Polymorphism (T-RFLP) analysis,are well-suited techniques for the examination of microbial community structures. The use of phylum and class-specific primers can provide enhanced sensitivity and phylogenetic resolution as compared with domain-specific primers. To date, several phylum- and class-specific primers targeting the 16S ribosomal RNA gene have been published. However, many of these primers exhibit low discriminatory power against non-target bacteria in PCR. In this study, we evaluated the precision of certain published primers in silico and via specific PCR. We designed new qPCR and T-RFLP primer pairs (for the classes Alphaproteobacteria and Betaproteobacteria, and the phyla Bacteroidetes, Firmicutes and Actinobacteria) by combining the sequence information from a public dataset (SILVA SSU Ref 102 NR) with manual primer design. We evaluated the primer pairs via PCR using isolates of the above-mentioned groups and via screening of clone libraries from environmental soil samples and human faecal samples. As observed through theoretical and practical evaluation, the primers developed in this study showed a higher level of precision than previously published primers, thus allowing a deeper insight into microbial community dynamics.

Iron deficiency alters megakaryopoiesis and platelet phenotype independent of thrombopoietin.

Iron deficiency is a common cause of reactive thrombocytosis, however, the exact pathways have not been revealed. Here we aimed to study the mechanisms behind iron deficiency-induced thrombocytosis. Within few weeks, iron-depleted diet caused iron deficiency in young Sprague-Dawley rats, as reflected by a drop in hemoglobin, mean corpuscular volume, hepatic iron content and hepcidin mRNA in the liver. Thrombocytosis established in parallel. Moreover, platelets produced in iron deficient animals displayed a higher mean platelet volume and increased aggregation. Bone marrow studies revealed subtle alterations that are suggestive of expansion of megakaryocyte progenitors, an increase in megakaryocyte ploidy and accelerated megakaryocyte differentiation. Iron deficiency did not alter the production of hematopoietic growth factors such as thrombopoietin, interleukin 6 or interleukin 11. Megakaryocytic cell lines grown in iron-depleted conditions exhibited reduced proliferation but increased ploidy and cell size. Our data suggest that iron deficiency increases megakaryopoietic differentiation and alters platelet phenotype without changes in megakaryocyte growth factors, specifically TPO. Iron deficiency-induced thrombocytosis may have evolved to maintain or increase the coagulation capacity in conditions with chronic bleeding.