Acta Microbiol. Hell., Volume 70, Issue 3 (September 2025) – 9 articles

Aeromonas is a genus of Gram-negative, facultatively anaerobic bacteria commonly found in aquatic environments and increasingly recognized as opportunistic pathogens. Among them, Aeromonas dhakensis stands out for its high virulence and antimicrobial resistance, but it is often misidentified due to its phenotypic similarity with A. hydrophila and A. caviae. In this study, a microorganism was isolated from the peritoneal fluid of a patient with signs of intra-abdominal infection. MALDI-TOF MS initially suggested A. hydrophila or A. caviae, but the identification was confirmed with high confidence only after further molecular analyses and the use of genome-based tools, which identified the organism as A. dhakensis. This was further supported by phylogenomic and ANI analysis. Resistome analysis revealed intrinsic resistance genes, including a chromosomal class C β-lactamase and an imiH-type carbapenemase, consistent with the observed carbapenem resistance. No plasmid-mediated carbapenemases were found. These findings underscore the limitations of MALDI-TOF in identifying Aeromonas species in certain cases and highlight the value of genomic approaches for accurate species determination and resistance profiling, especially for isolates from sterile body fluids. Full article

Sexually transmitted infections (STIs) are a significant global health concern, affecting millions of people worldwide, particularly sexually active adolescents and young adults. These infections, caused by various pathogens, including bacteria, viruses, parasites, and fungi, can have profound implications for women’s reproductive health and fertility. This review explores the role of vaginal and uterine infections in women’s infertility, focusing on the most common pathogens and their impact on reproductive outcomes. Bacterial infections, such as those caused by intracellular bacteria (Mycoplasma, Ureaplasma, and Chlamydia), Neisseria gonorrhoeae, and bacterial vaginosis, are among the most prevalent causes of infertility in women. Studies have shown that these infections can lead to pelvic inflammatory disease, tubal occlusion, and endometrial damage, all of which can impair fertility. Mycobacterium tuberculosis, in particular, is a significant cause of genital tuberculosis and infertility in high-incidence countries. Viral infections, such as Human papillomavirus (HPV) and Herpes simplex virus (HSV), can also affect women’s fertility. While the exact role of HPV in female infertility remains unclear, studies suggest that it may increase the risk of endometrial implantation issues and miscarriage. HSV may be associated with unexplained infertility. Parasitic infections, such as trichomoniasis and schistosomiasis, can directly impact the female reproductive system, leading to infertility, ectopic pregnancy, and other complications. Fungal infections, such as candidiasis, are common but rarely have serious outcomes related to fertility. The vaginal microbiome plays a crucial role in maintaining reproductive health, and alterations in the microbial balance can increase susceptibility to STIs and infertility. Probiotics have been proposed as a potential therapeutic strategy to restore the vaginal ecosystem and improve fertility outcomes, although further research is needed to establish their efficacy. In conclusion, vaginal and uterine infections contribute significantly to women’s infertility, with various pathogens affecting the reproductive system through different mechanisms. Early diagnosis, appropriate treatment, and preventive measures are essential to mitigate the impact of these infections on women’s reproductive health and fertility. Full article

This study assessed microbiological contamination in street-sold meat products, focusing on Enterobacterales and coagulase-negative staphylococci (CoNS) species and their antibiotic resistance. Chicken and mutton street foods like shawarma and brochettes were tested for bacterial load, species distribution. and resistance profiles. The results showed significant contamination, with Enterobacter cloacae (5.38 Log 10 CFU/g). Staphylococcus lentus and Staphylococcus xylosus were also common, reaching 6.23 Log 10 CFU/g in some samples. Contamination levels varied significantly by food type, with chicken shawarma showing the highest risk. Antimicrobial susceptibility testing revealed high multidrug resistance, particularly among E. cloacae and Staphylococcus species. Biofilm formation an indicator of resistance was observed mainly in staphylococci and enhanced under fed-batch culture. These findings highlight public health concerns tied to poor hygiene and undercooking in street food environments. The study emphasizes the need for improved hygiene practices, standardized cooking methods, and systematic food safety monitoring to reduce contamination and antibiotic resistance risks. Full article

Syphilis, which is caused by Treponema pallidum, remains one of the most common congenital infection worldwide and has tremendous consequences for the mother and her developing foetus if left untreated. The complexity of the exposure to this pathogen extends beyond the well-established clinical manifestations, as it can profoundly affect placental histomorphology. This study aimed to compare T. pallidum-exposed placental villi structures with healthy placentae at term to evaluate the histomorphological differences using stereology. In this case-control study conducted at term (38 weeks ± 2 weeks), 78 placentae were collected from the hospital delivery suites, comprising 39 cases (T. pallidum-exposed) and 39 controls (non-exposed), who were gestational age-matched with other potential confounders excluded. Blood samples from the umbilical vein and placental basal plate were tested for syphilis, using rapid diagnostic test (RDT) kits for T. pallidum (TP) antibodies (IgG and IgM) to classify placentae as exposed to T. pallidum (cases) and non-exposed (controls). Tissue sections were prepared and stained with haematoxylin and eosin, and the mean volume densities of syncytial knots, foetal capillaries, syncytial denuded areas, and intervillous spaces were estimated using stereological methods. Statistical analysis was performed to compare the mean values between the case and control groups. Stereological assessment revealed significant differences between the T. pallidum-exposed and non-exposed groups with regard to syncytial knots (p < 0.0001), syncytial denudation (p < 0.0001), and foetal capillaries (p < 0.0001), but no significant difference in the intervillous space was found (p = 0.1592). Therefore, our study shows, for the first time, that the histomorphology of human placental villi appears to be altered by exposure to T. pallidum. It will, therefore, be interesting to determine whether these changes in the placental villi translate into long-term effects on the baby. Full article

The excessive use of antimicrobials drives the emergence of multidrug resistance (MDR) in bacterial strains, which harbor resistance genes to survive under diverse drug pressures. Such resistance can result in life-threatening infections. The predominance of MDR Pseudomonas spp. poses significant challenges to public health and environmental sustainability, particularly in ecosystems affected by human activities. Characterizing MDR Pseudomonas spp. is crucial for developing effective diagnostic tools and biosecurity protocols, with broader implications for managing other pathogenic bacteria. Strains were diagnosed through 16S rRNA PCR and sequencing, complemented by phylogenetic analysis to evaluate local and global evolutionary connections. Antibiotic susceptibility tests revealed extensive resistance across multiple classes, with MIC values surpassing clinical breakpoints. This study examined the genetic diversity, resistance potential, and phylogenetic relationships among Pseudomonas aeruginosa strain DG2 and Pseudomonas fluorescens strain FM3, which were isolated from solid waste dump sites (n = 30) and dairy farms (n = 22) in West Bengal, India. Phylogenetic analysis reveals distinct clusters that highlight significant geographic linkages and genetic variability among the strains. Significant biofilm production under antibiotic exposure markedly increased resistance levels. RAPD-PCR profiling revealed substantial genetic diversity among the isolates, indicating variations in their genetic makeup. In contrast, SDS-PAGE analysis provided insights into the protein expression patterns that are activated by stress, which are closely linked to MDR. This dual approach offers a clearer perspective on their adaptive responses to environmental stressors. This study underscores the need for vigilant monitoring of MDR Pseudomonas spp. in anthropogenically impacted environments to mitigate risks to human and animal health. Surveillance strategies combining phenotypic and molecular approaches are essential to assess the risks posed by resilient pathogens. Solid waste and dairy farm ecosystems emerge as critical reservoirs for the evolution and dissemination of MDR Pseudomonas spp. Full article

Trichomonas vaginalis infection (TVI) is the most common curable sexually transmitted infection (STI). In this study, we aimed to assess the performances of different tests for TVI diagnosis in symptomatic Greek women, evaluating the TVI prevalence rate (PR) in Greece and comparing the latter with TVI-PR estimates from Europe. A laboratory-based cross-sectional analysis and a meta-analysis were conducted. Of 399 symptomatic Greek women, 17 had TVI, corresponding to a TVI-PR of 4.3%. The commercial nucleic acid amplification test (NAAT) achieved a sensitivity of 94.1%, which was 6% higher than the sensitivity of the culture method, 35% higher than that of the wet mount test, and 59% higher than that of the Giemsa stain test. The wet mount test achieved the lowest positive predictive value of 76.9%. All the tests had high specificity levels and negative predictive values. Data from 34 European TVI-PR studies in symptomatic women were pooled. The TVI-PR established in our study was similar to the TVI-PR estimates of 4.8% in Europe and 4.5% in Greece, with the second being higher than those of 2.1% in Northwestern Europe and 1.5% in Southern Europe but closer to that of 6.7% in Türkiye. In Greece, a European country with a relatively high TVI-PR among symptomatic women, the highly sensitive and specific, automated, point-of-care NAAT would facilitate rapid, accurate TVI diagnosis and the treatment of this target population to meet the WHO’s goal of ending STI epidemics by 2030. Full article

Beta-thalassemia major is an inherited disorder that requires lifelong blood transfusions, with the risk of complications including poor oral health and dental caries. The objective of this study was to compare the oral microbiome diversity and composition in transfusion-dependent thalassemia patients and relate it to oral hygiene and dental caries. A cross-sectional analysis of 35 patients of beta-thalassemia major aged 6–18 years was performed. The status of oral hygiene was examined through the Oral Hygiene Index—Simplified (OHI-S) and Decayed, Missing, and Filled Teeth (DMFT) index. Saliva was taken for DNA extraction, followed by the 16S rRNA sequencing of V3-V4 hypervariable regions. The bioinformatics pipeline in QIIME2 was utilized for analyzing the comparison of microbial composition and diversity in groups of varying oral hygiene status and severity of caries. Metagenomic analysis revealed 3334 Amplicon Sequence Variants (ASVs), of which the most prevalent genera were Streptococcus, Haemophilus, Veillonella, Rothia, and Prevotella. High-oral-hygiene groups presented increased levels of cariogenic bacteria, while moderate-oral-hygiene groups presented an equilibrated microbiome. No statistically significant differences in microbial diversity were found between the study groups (p > 0.05). This study sheds light on the critical importance of oral hygiene in microbiome diversity in patients with beta-thalassemia major. Full article

Dengue virus infection (DVI), a mosquito-borne arboviral infection, is prevalent in tropical and subtropical regions, including Bangladesh, where incidence has surged over the past three decades—particularly in urban and peri-urban areas. This study investigates the factors influencing DVI seropositivity among clinically suspected patients admitted to the selected hospitals of Savar, Dhaka, and Chattogram. Data were collected from 850 clinically suspected patients admitted to two hospitals in Savar, Dhaka, and two in Chattogram during 2019. Questionnaire responses and laboratory test results (NS1, IgM, and IgG) were analyzed using descriptive statistics, chi-square tests, and logistic regression. Out of 450 admissions in Savar, 330 tested positive, while Chattogram reported 145 positives from 400 cases. No significant differences were observed between regions in relation to hospital type, season, gender, or household preventive measures. In Savar, DVI status was significantly associated with season, mosquito net use, and patient contact. In Chattogram, household repellent use and patient contact were key factors. Diagnostic tests varied in detection capability. These findings can inform targeted intervention strategies and public health messaging, such as promoting personal protection measures and community awareness campaigns, particularly in high-incidence urban settings. However, further research across diverse geographic and socio-ecological contexts is needed to enhance the generalizability and policy relevance of these results. Full article

Vaginitis is a major health concern among women, with inadequate treatment potentially leading to reproductive complications. This study aimed to assess vaginitis prevalence, identify predominant pathogens, and evaluate associated risk factors among female patients at Da Nang Dermato-Venereology Hospital. A prospective study of 796 female patients undergoing physical examinations was conducted, with demographic, clinical, and microbiological data collected. Vaginitis was diagnosed in 180 (22.6%) of 796 female patients, predominantly caused by Candida spp. (66.1%) and bacterial pathogens (31.7%), with no Trichomonas vaginalis detected, and was most prevalent in women aged 20–30 years. Poor hygiene practices, including infrequent sanitary pad changes (OR = 5.01, p < 0.001) and routine vaginal douching (OR = 6.77, p < 0.001), were significantly associated with vaginitis. The Amsel criteria showed high specificity (99.1%) for bacterial vaginosis diagnosis. The absence of T. vaginalis suggests a potential shift in the epidemiology of vaginal infections. The Amsel criteria are a practical diagnostic tool in resource-limited settings. Our findings highlight the need for targeted hygiene education to reduce vaginitis prevalence in Vietnam. Full article