- Volume 74, Issue 3, 2025

Multidrug resistance has been reported in group B Streptococcus (GBS) from various origins, but rates among urinary tract infection (UTI) isolates are largely unknown. Erythromycin, a second-line antibiotic for GBS for which high rates of resistance have been reported, was recently shown to support the resistance of Staphylococcus to oxidative stress. To survey multidrug-resistant (MDR) GBS from UTI and to investigate the effect of erythromycin exposure on the bacteria’s ability to resist oxidative stress, we determined the antibacterial activity of 18 antibiotics against 292 GBS UTI isolates by disc diffusion and used in vitro growth assays of MDR GBS exposed to erythromycin to examine relative resistance to oxidative stress in the form of H2O2. A high proportion of all 292 GBS isolates (33.6%) were MDR, reflecting high rates of resistance to four antibiotics: azithromycin (44.5%), clindamycin (26%), erythromycin (36.3%) and tetracycline (81.5%); however, no resistance was detected for any other antibiotics tested. Rates of resistance were not significantly different when analysed according to clinical origins (acute and recurrent UTI, asymptomatic bacteriuria). The growth of MDR GBS was attenuated and severely inhibited by exposure to erythromycin and H2O2, respectively. Surprisingly, exposure of MDR GBS to erythromycin significantly relieved the severe growth inhibitory effect of H2O2, signifying a partial rescue effect of the antibiotic. The GBS isolates in this study exhibit high levels of multidrug resistance without an association between resistance and clinical origin. Exposure of MDR GBS to erythromycin can partially counteract the severe growth inhibitory effect from H2O2.

Introduction. The contact surfaces in hospitals serve as reservoirs for pathogens and account for 20–40% of hospital-acquired infections. This resistance is mainly attributed to the biofilm-forming ability of the microbes. These biofilms restrict the entry of the antibiotics to penetrate them, thus giving rise to drug resistance. Hence, there is a renewed interest in formulating an environmentally friendly, non-allergic, quick mode of action, broad-spectrum disinfectant.

Hypothesis. We hypothesize that the pure compounds present in the pyrolysis aqueous phase could act as an anti-infective and anti-biofilm agent.

Aim. The present work investigates the effectiveness of furfuryl alcohol, 2-methyl-2-cyclopentenone and guaiacol as effective anti-infective agent followed by testing its biofilm eradication potential against the mixed species of multidrug-resistant pathogens such as Acinetobacter baumannii, methicillin-resistant Staphylococcus aureus and Candida auris.

Methodology. The MIC and fractional inhibitory concentrations (FIC) of the pure compounds were determined using checkerboard assay for two-compound and three-compound combinations. The biofilm eradication concentration was performed on stainless coupons, followed by RNA isolation and quantitative PCR (qPCR) analysis to elucidate virulence gene downregulation.

Results. The individual MICs of furfuryl alcohol, 2-methyl-2-cyclopentenone and guaiacol were found to be 8%, 9% and 2% (v/v), respectively. The two-compound combination FIC index of 0.75 showed partial synergy between the compounds, while the three-compound combination showed an additive effect with a FIC index of 0.87. Further, at ½ FIC (biofilm inhibitory concentration), the compounds showed 52% eradication of preformed biofilms on the hospital contact surfaces (stainless steel). The growth and time-to-kill curve showed that the compounds were not lethal to planktonic cells at BIC. Finally, the qPCR analysis showed a reduction in the expression levels of biofilm and adhesion genes, while the Quorum sensing (QS) genes were affected much more, elucidating a possible eradication mechanism.

Conclusion. From this study, we have found a new class of compounds that have potential disinfecting ability. With the current knowledge, the future lead would be to effectively use them in disinfectant formulations.

Introduction. Antimicrobial resistance (AMR) poses a critical threat to global health, underscoring the need for rapid and accurate diagnostic tools. Methicillin-resistant Staphylococcus aureus (MRSA) and extended-spectrum beta-lactamase (ESBL)-producing Klebsiella pneumoniae (ESBL-Kp) are listed among the World Health Organization’s priority pathogens.

Hypothesis. A rapid nanopore-based protocol can accurately and efficiently detect AMR genes, virulence factors (VFs) and mobile genetic elements (MGEs) in MRSA and ESBL-Kp, offering performance comparable to or superior to traditional sequencing methods.

Aim. Evaluate whole-genome sequencing (WGS) protocols for detecting AMR genes, VFs and MGEs in MRSA and ESBL-Kp, to identify the most accurate and efficient tool for pathogen profiling.

Methodology. Five distinct WGS protocols, including a rapid nanopore-based protocol (ONT20h) and four slower sequencing methods, were evaluated for their effectiveness in detecting genetic markers. The protocols' performances were compared across AMR genes, VFs and MGEs. Additionally, phenotypic antimicrobial susceptibility testing was performed to assess concordance with the genomic findings.

Results. Compared to four slower sequencing protocols, the rapid nanopore-based protocol (ONT20h) demonstrated comparable or superior performance in AMR gene detection and equivalent VF identification. Although MGE detection varied among protocols, ONT20h showed a high level of agreement with phenotypic antimicrobial susceptibility testing.

Conclusion. The findings highlight the potential of rapid WGS as a valuable tool for clinical microbiology, enabling timely implementation of infection control measures and informed therapeutic decisions. However, further studies are required to optimize the clinical application of this technology, considering costs, availability of bioinformatics tools and quality of reference databases.

Introduction. Eye diseases are widespread all over the world and, if left untreated, can lead to blindness.

Hypothesis. The use of 0.05% cyclosporine A (CsA) solution for the treatment of dry eye causes a decrease in discomfort and pain and improves objective measures such as tear film breakdown time, Schirmer test results and Oxford scale scores due to its anti-inflammatory and immunomodulatory properties that contribute to improved tear film stability and tear production.

Aim. This study aimed to investigate the impact of CsA on the progression of ocular surface diseases.

Methodology. An experiment was conducted on the basis of the FOCUS ophthalmology centre, Kazakhstan. A group of 100 individuals diagnosed with mild to severe dry eye illness were administered 0.05% CsA eye drops as part of the treatment protocol.

Results. The positive effect is explained by the anti-inflammatory and immunomodulatory effects of CsA. The study showed that the use of 0.05% CsA solution for the treatment of ocular surface disease led to a decrease in discomfort and pain, as well as an improvement in objective measures, including tear film breakdown time, Schirmer test results and Oxford scale scores. The visual analogue scale showed a significant reduction in symptoms, from 6.8 points at baseline to 3.7 points at day 60. In total, 20% of patients reported moderate side effects, such as pain during instillation and redness of the eye surface.

Conclusion. It is concluded that the use of these drops reduced pain, improved patient condition and enhanced indicators such as the visual analogue scale, tear film breakup time, Schirmer test and Oxford scale of corneal and conjunctival staining. This study differs from the previous ones in that it focuses on the efficacy of 0.05% CsA solution in the treatment of dry eye and also examines the spectrum and frequency of side effects, which is not sufficiently covered in previous studies.

Introduction. Invasive meningococcal disease (IMD) is a nationally notifiable illness in Canada due to its potential severity and transmissibility. Vaccination strategies differ by province/territory and are informed by changes in the antigenic characteristics of circulating strains.

Gap Statement. Though IMD statistics are tracked at a provincial/territorial level, there is a lack of published data characterizing trends in the epidemiology of this disease at a national level.

Aim. To examine the epidemiology of culture-confirmed IMD in Canada during the period of 2015–2023.

Methodology. Meningococcal isolates sent to the National Microbiology Laboratory Branch between 2015 and 2023 as part of routine national surveillance were characterized for serogroup by bacterial agglutination and genetic methods. Clonal analysis was done by MLST. Demographic information was derived from requisition forms accompanying the samples.

Results. The proportion of IMD caused by serogroup W meningococci (MenW) in 2015–2023 was 30.0% with more (62.9%) MenW cases detected in western provinces. Serogroup B meningococci (MenB) IMD was more common (53.4%) in Quebec and Atlantic Canada. Clonal analysis reveals 168 distinct sequence types between 2015 and 2023, with 103 belonging to MenB. The average age of MenB cases during this time was 29.1 years, significantly younger than serogroup C (MenC) (45.3 years), serogroup Y (MenY) (48.3 years) and MenW (43.0 years) patients. Additionally, 31.5% of MenB and 21.7% of MenC IMD isolates were collected from cerebrospinal fluid (CSF) or brain samples, which were significantly higher than that for MenY (12.2%) and MenW (7.3%) isolates.

Conclusions. Results from this and previous studies showed temporal and geographical variations in the serogroups causing IMD in Canada. MenB also showed the most genetic diversity, caused IMD in a significantly younger population and was more often isolated from CSF and brain samples than other serogroups.

Introduction. Oral contraceptives (OCs) are widely used for birth control and offer benefits such as menstrual cycle regulation and reduced menstrual pain. However, they have also been associated with an increased risk of cancer and reduced bone mass density.

Gap Statement. While the gut microbiome is known to interact with endocrine factors, the impact of hormonal OCs on its composition and function remains underexplored. Additionally, we explore the relationship of OC use and the microbiome to gas production, which can cause symptoms and be indicative of poor health.

Aim. This study investigates the effects of OCs on the diversity and composition of the gut microbiome and its association with breath hydrogen (H2) and methane (CH4) levels.

Methodology. We utilized 16S rRNA gene sequencing to analyse faecal samples from 65 women, comparing OC users with non-users at two menstrual cycle time points. Breath tests measured hydrogen and CH4 production. Data were analysed for microbial diversity, community composition and correlation with gas production.

Results. There were no differences in overall microbial diversity between OC users and non-users in samples collected on day 2 of the menstrual cycle. However, on day 21, we found a significant difference in microbial richness, suggesting a cycle-dependent effect of OCs on gut microbiota species richness but not composition. We found a strong correlation between H2 and CH4 concentrations and an interaction between OC use and the menstrual cycle on H2 and CH4 production. We also identified several taxa associated with both high levels of H2 and CH4 production and OC use.

Conclusion. Our study highlights the intricate relationships among hormonal contraceptives, the gut microbiota and gas production and connects shifts in the microbiome composition to gastrointestinal symptoms (e.g. gas production) that can impact overall health. This underscores the need for further research on the long-term effects of OCs and for the development of precise therapeutic strategies to address potential adverse effects. Our findings offer new perspectives on the microbiome–hormone–gas production nexus, potentially broadening our understanding of the systemic implications of OCs.

Introduction . Helicobacter pylori infection is a major cause of peptic ulcer and gastric adenocarcinoma. The infection progression to severe diseases depends on several factors, including bacterial ones. CagA and VacA are two major virulence factors widely studied and implicated in H. pylori diseases.

Gap statement. Although the allelic prevalence of the s, m, i and d regions of the H. pylori vacA gene and their relation with gastric disease outcomes have been largely studied, there is a gap in knowledge regarding the prevalence and the association of the vacA c region with those pathologies. This polymorphic region could exhibit a large variability which might impact the virulence of the bacterium and the severity of gastric damage.

Aim. The aim of this study was to investigate the prevalence of H. pylori vacA c alleles and to assess the association of vacA mosaicism with gastric damage in a large Moroccan population.

Methodology. H. pylori positive gastric biopsies, obtained in 709 consenting patients who consulted the gastroenterology department of the Hassan II University Hospital of Fez (Morocco) for clinical endoscopy, between 2009 and 2019, were used in this study. DNA extracted from the biopsy samples was used to determine the vacA c genotype using specific PCRs. H. pylori cagA, vacA s, vacA m, vacA d and vacA i genotypes of these samples were previously determined.

Results. The vacA c2 genotype was detected in 44.7% of samples and the vacA c1 genotype in 16.5% of cases. Multiple infections (detection of the two vacA c allelic forms) were obtained in 9% of samples. Correlation of H. pylori vacA c genotype with pathologies showed that the vacA c1 allele was strongly associated with the risk of gastric cancer (GC) [odds ratio=3.14, confidence intervals 95% (1.08–9.09)].

Conclusion. The results of this study confirm that despite the large H. pylori genetic diversity, the genotypic distribution is marked by a predominance of the less virulent strains in Morocco. Also, even if vacA allelic combinations seem to impact the toxicity of this bacterium, patients infected with H. pylori vacA c1 genotype are more likely to develop GC than those infected by H. pylori vacA c2 genotype.

Introduction. Group B Streptococcus (GBS) is a multi-host pathogen causing pneumonia and meningitis in humans as well as streptococcal diseases in tilapia and mastitis in cattle. Thailand has experienced a significant increase in GBS infections that greatly impact health and economics.

Gap statement. The antimicrobial resistance (AMR) and genotype data of GBS in Thailand are still limited and require further study.

Aim. This study aimed to describe AMR profiles and molecular characteristics, especially antimicrobial resistance genes (ARGs) and virulence factor (VF) genes of GBS in Thailand.

Methodology. AMR profiles of 221 GBS isolates from humans, fish and freshwater were examined. Whole-genome sequencing of 41 representative isolates was used to investigate capsular genotypes and sequence types (STs), ARGs and VF genotypes.

Results. All GBS isolates were susceptible to penicillin; the majority (99.1%) showed resistance to tetracycline. In addition, the rates of resistance to clindamycin, erythromycin and levofloxacin were 22.6%, 20.4% and 2.3%, respectively; multidrug-resistant (MDR) isolates (TE-E-CM and TE-E-CM-LVX) were 19.5%. Among 41 representative isolates, the dominant types were capsular genotype III (63.4%) and ST283 (43.9%). ARGs associated with resistance to tetracycline (tetM, tetO and tetS), erythromycin (ermB, ermA, mefA and msrD) and clindamycin (lsaC, lsaE and lnuB) were identified. Additionally, point mutations responsible for levofloxacin resistance, S81L in GyrA, S79F/Y in ParC and H221Y in ParE, were found. The MDR isolates belonged to various STs, predominantly clustering in capsular types III (60.0%) and Ib (30.0%). The MDR-hypervirulent ST17 and ST19 harboured multiple ARGs and mutations affecting quinolone resistance. Different VF gene patterns were found among hypervirulent STs (ST12, ST17, ST19 and ST283). Notably, a unique nt deletion [c.(1013_1020)delG] in pilA was found only in ST283.

Conclusion. This study elucidated significant antimicrobial characteristics of a substantial number of GBS in Thailand. Moreover, the distribution of the hypervirulent ST283 and the genotypes of MDR-hypervirulent GBS were first described.

Introduction. The human papillomavirus (HPV) is one of the main oncogenic viruses. High-risk HPV types are associated with the development of cervical cancers. In addition, it is known that some mutations in HPV genes, or variant viral lineages, have been associated with greater oncogenic risk.

Gap statement. The L1 protein is the major component of the viral capsid and is therefore used in currently available vaccines. However, the characterization of mutations in the L1 gene, which is relevant to increasing the knowledge of the immune escape mechanisms used by the virus, is still incipient.

Aim. This study aimed to characterize mutations associated with antigenic domains in the L1 protein of HPVs isolated from cervical samples of women living with HIV in Northeastern Brazil.

Methodology. L1 gene sequences were obtained from the samples, and the mutations and the viral variants were characterized. Phylogenetic and functional analyses of the structure of the L1 protein were carried out.

Results. A total of 41 HPV variant isolates were obtained, distributed among 16 different viral types. Of this, 25 non-synonymous mutations were evaluated regarding the stability of the L1 protein. It was observed that 10 of these mutations were predicted to increase, and 14 to decrease, the stability of the L1 protein and that most of them occurred in the FG hypervariable antigenic loop.

Conclusion. These results add useful knowledge to understanding the biological and immunological aspects of HPV variants and the impact of these mutations on the development of vaccine strategies.