Alexander Guschin

Dr. Alexander Guschin


Research Focus & Metrics

Academic Career Length

12Years (2015-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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3 February 2015 in BMC Infectious Diseases
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Alexander GuschinAlexander Guschin
Alexander Guschin
PRPavel Ryzhikh
Pavel Ryzhikh
TRTatiana Rumyantseva
Tatiana Rumyantseva
MGMikhail Gomberg
Mikhail Gomberg
MUMagnus Unemo
Magnus Unemo
Azithromycin has been widely used for Mycoplasma genitalium treatment internationally. However, the eradication efficacy has substantially declined recent decade. In Russia, josamycin (another macrolide) is the recommended first-line treatment for M. genitalium infections, however, no data regarding treatment efficacy with josamycin and resistance in M. genitalium infections have been internationally published. We examined the M. genitalium prevalence in males attending an STI clinic in Moscow, Russia from December 2006 to January 2008, investigated treatment efficacy with josamycin in male urethritis, and monitored the M. genitalium DNA eradication dynamics and selection of macrolide resistance in M. genitalium during this treatment. Microscopy and real-time PCRs were used to diagnose urethritis and non-viral STIs, respectively, in males (n = 320). M. genitalium positive patients were treated with recommended josamycin regimen and treatment efficacy was monitored using quantitative real-time PCR. Macrolide resistance mutations were identified using sequencing of the 23S rRNA gene. Forty-seven (14.7%) males were positive for M. genitalium only and most (85.1%) of these had symptoms and signs of urethritis. Forty-six (97.9%) males agreed to participate in the treatment efficacy monitoring. All the pre-treatment M. genitalium specimens had wild-type 23S rRNA. The elimination of M. genitalium DNA was substantially faster in patients with lower pre-treatment M. genitalium load, and the total eradication rate was 43/46 (93.5%). Of the six patients with high pre-treatment M. genitalium load, three (50%) remained positive post-treatment and these positive specimens contained macrolide resistance mutations in the 23S rRNA gene, i.e., A2059G (n = 2) and A2062G (n = 1). M. genitalium was a frequent cause of male urethritis in Moscow, Russia. The pre-treatment M. genitalium load might be an effective predictor of eradication efficacy with macrolides (and possibly additional antimicrobials) and selection of macrolide resistance. Additional in vivo and in vitro data are crucial to support the recommendation of using josamycin as first-line treatment for M. genitalium infections in Russia. It would be valuable to develop international M. genitalium management guidelines, and quantitative diagnostic PCRs determining also M. genitalium load and resistance mutations (for macrolides and ideally also moxifloxacin) should ideally be recommended.

8 January 2021 in Pathogens
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CLChristine Landlinger-Schubert
Christine Landlinger-Schubert
LTLenka Podpera Tišáková
Lenka Podpera Tišáková
Vera OberbauerVera Oberbauer
Vera Oberbauer
TSTimo Schwebs
Timo Schwebs
AMAbbas Muhammad
Abbas Muhammad
LCLorenzo Corsini
Lorenzo Corsini
Bacterial vaginosis is characterized by an imbalance of the vaginal microbiome and a characteristic biofilm formed on the vaginal epithelium, which is initiated and dominated by Gardnerella bacteria, and is frequently refractory to antibiotic treatment. We investigated endolysins of the type 1,4-beta-N-acetylmuramidase encoded on Gardnerella prophages as an alternative treatment. When recombinantly expressed, these proteins demonstrated strong bactericidal activity against four different Gardnerella species. By domain shuffling, we generated several engineered endolysins with 10-fold higher bactericidal activity than any wild-type enzyme. When tested against a panel of 20 Gardnerella strains, the most active endolysin, called PM-477, showed minimum inhibitory concentrations of 0.13–8 µg/mL. PM-477 had no effect on beneficial lactobacilli or other species of vaginal bacteria. Furthermore, the efficacy of PM-477 was tested by fluorescence in situ hybridization on vaginal samples of fifteen patients with either first time or recurring bacterial vaginosis. In thirteen cases, PM-477 killed the Gardnerella bacteria and physically dissolved the biofilms without affecting the remaining vaginal microbiome. The high selectivity and effectiveness in eliminating Gardnerella, both in cultures of isolated strains as well as in clinically derived samples of natural polymicrobial biofilms, makes PM-477 a promising alternative to antibiotics for the treatment of bacterial vaginosis, especially in patients with frequent recurrence.

5 February 2019 in Molecular Diagnosis & Therapy
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ESElena Shipitsyna
Elena Shipitsyna
ASAnna Siniakova
Anna Siniakova
GKGuzel Khayrullina
Guzel Khayrullina
KSKira Shalepo
Kira Shalepo
Alevtina Mikhailovna SavichevaAlevtina Mikhailovna Savicheva
Alevtina Mikhailovna Savicheva
MUMagnus Unemo
Magnus Unemo
Background Bacterial vaginosis (BV) is a vaginal disorder characterized by a depletion of the normal lactobacillus-dominant microbiota and overgrowth of mainly anaerobic bacteria. Objectives The study aimed to evaluate the distribution and abundance of the Gardnerella vaginalis clades and sialidase A gene in vaginal samples from Russian women, and investigate if the G. vaginalis sialidase A gene count detects an abnormal vaginal microbiota characteristic of BV more accurately than G. vaginalis load. Methods Vaginal samples from 299 non-pregnant patients of gynecological clinics were examined using Nugent scores and G. vaginalis clade and sialidase A gene quantitative real-time polymerase chain reactions (PCRs). Discriminatory power for BV microbiota was evaluated with receiver operating characteristic (ROC) analysis. Results The vaginal microbiota was characterized by Nugent scores as normal, intermediate, and BV microbiota in 162, 58, and 79 women, respectively. G. vaginalis clades 1, 2, 3, 4, and the sialidase A gene were detected in 56% (51–62%), 40% (34–45%), 20% (16–25%), 94% (91–96%), and 70% (64–75%) of vaginal samples, respectively. The frequency and abundance of clades 1, 2, 4, and the sialidase A gene as well as clade multiplicity were significantly associated with abnormal microbiota. The sialidase A gene was present in all multi-clade samples, in all single-clade samples comprising clades 1, 2, and 3, and in four of 84 (5% [2–12%]) samples comprising clade 4 only. Total G. vaginalis load showed significantly higher discriminatory power for abnormal microbiota than sialidase A gene count (areas under ROC curves 0.933 vs. 0.881; p = 0.0306). Conclusions Quantifying all four G. vaginalis clades discriminates between BV microbiota and normal microbiota more accurately than measuring G. vaginalis sialidase A gene. Clade 4 is strongly associated with BV microbiota, despite most clade 4 strains lacking the sialidase A gene.

11 April 2022 in Pathogens
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Alexander SwidsinskiAlexander Swidsinski
Alexander Swidsinski
Alexander GuschinAlexander Guschin
Alexander Guschin
LCLorenzo Corsini
Lorenzo Corsini
VLVera Loening-Baucke
Vera Loening-Baucke
LTLenka Podpera Tišáková
Lenka Podpera Tišáková
YDYvonne Dörffel
Yvonne Dörffel
Background: Testing of antibiotic resistance of intact vaginal microbiota in pure culture is not feasible. METHODS: Metronidazole, antiseptic octenisept®, antimycotic ciclopirox, bacterial probiotic Lactobacillus crispatus, yeast probiotic Saccharomyces boulardii, Gardnerella-phage-endolysin named phagolysin and phagolysin in combination with probiotics were tested for bacteriolytic activity. Included were vaginal swabs from 38 random women with Amsel-confirmed bacterial vaginosis (BV). Test aliquots were incubated by 37° for 2 and 24 h. Gardnerella, low G+C, Atopobium, lactobacilli, Lactobacillus iners and crispatus, Prevotella-Bacteroides, and Gammaproteobacteria microbial groups were quantified using fluorescence in situ hybridization (FISH). Results: The probiotic strain Lactobacillus crispatus demonstrated the weakest bacteriolytical effects, followed by metronidazole. Both had no impact on Gardnerella species, instead lysing Prevotella-Bacteroides, Enterobacteriaceae (by L.crispatus) or LGC, Atopobium and Prevotella-Bacteroides (by metronidazole) groups of the microbiota. Cytolytic activity on Gardnerella was highly pronounced and increased from octenisept to ciclopirox, phagolysin, phagolysin with L.crispatus, being best in the combination of phagolysin with S.boulardii. Universally active ciclopirox and octenisept® suppressed nearly all microbial groups including those which are regarded as beneficial. Phagolysin had no effect on naturally occurring Lactobacillus crispatus. Conclusions: FISH susceptibility testing allows unique efficacy evaluation of individually adjusted topical therapy without microbial isolation facilitating optimal therapy choice.


18 March 2020 in Sexually Transmitted Infections
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ABAdeline Bernier
Adeline Bernier
TRTatiana Rumyantseva
Tatiana Rumyantseva
LRLaura Reques
Laura Reques
NVNatalia Volkova
Natalia Volkova
YKYan Kyburz
Yan Kyburz
DPDominique Pataut
Dominique Pataut
To estimate the prevalence and factors associated with HIV and five other STIs among outdoor female sex workers (OSFW) and indoor FSW (IFSW).Methods: Cross-sectional survey using respondent-driven sampling methodology. Participants answered a bio-behavioural questionnaire and were tested forNeisseria gonorrhoeae(NG),Chlamydia trachomatis(CT),Trichomonas vaginalis(TV), syphilis (lifetime contact) andMycoplasma genitalium(MG). Weighted HIV and other STIs prevalence and 95% CIs were calculated. Weighted multivariate logistic regression was performed to identify factors associated with having at least one STI (including HIV).Results: Between October 2017 and July 2018, 385 FSW participants were recruited, among whom 206 (53.5%) were IFSW and 179 (46.5%) were OFSW. The mean age was 31.4 years. Weighted HIV prevalence was 3.1% (95% CI 1.5 to 7.0). Weighted prevalence of other STIs was: 4.1% (95% CI 2.2 to 8.0) for NG, 8.8% (95% CI 5.9 to 13.0) for CT, 12.7% (95% CI 8.6 to 18.0) for TV, 13.9% (95% CI 9.9 to 19.0) for syphilis (lifetime contact) and 14.9% (95% CI 10.5 to 21.0) for MG. STI prevalence was significantly higher among OFSW for CT, TV and MG (p<0.001). In total, 43.2% of the participants had at least one HIV/STI. Factors associated with having HIV/STI were being an OFSW (OR 3.29; 95% CI 1.72 to 6.27); being registered in another Russian region (2.61 (95% CI 1.05 to 6.48)); having never been tested for HIV (2.51 (95% CI 0.98 to 6.41)) and having a low level of knowledge regarding HIV transmission (4.88 (95% CI 0.96 to 24.78)).Conclusion: Prevalence of HIV and STIs was high among FSW in Moscow. OFSW were more vulnerable to STIs. There is an urgent need to tailor programmes for sexual and reproductive health for FSW in Russia.