Acta Microbiologica Hellenica

The human microbiota plays a crucial role in maintaining host health through its considerable influence on immune function, nutrient metabolism, and overall homeostasis. While trace metals such as cobalt, lithium, and nickel are essential micronutrients at low concentrations, their increasing environmental accumulation presents emerging risks for microbial dysbiosis and related systemic health effects. This review examines the dual role of these trace metals as both beneficial nutrients and potential disruptors of microbial balance. Specifically, cobalt supports microbial diversity through its role in vitamin B12 synthesis, but excessive exposure can lead to dysbiosis. Lithium, beneficial at therapeutic concentrations by enhancing beneficial microbial populations, adversely affects gut barrier integrity by promoting inflammation and epithelial damage at higher concentrations. Similarly, nickel participates in essential enzymatic activities but promotes dysbiosis and inflammatory responses at elevated exposures. Furthermore, the growing environmental contamination by these metals poses risks to food systems and various microbial communities in the environment. Highlighting these environmental concerns, this review calls for sustainable management and multidisciplinary research to mitigate health risks to mitigate health risks associated with trace metal exposure. Full article

In developing countries like Bangladesh, livestock is one of the main sources of income. Among several infectious diseases, the Gram-positive bacterium Bacillus anthracis causes a zoonotic disease named anthrax. Animal anthrax outbreaks are a frequently occurring problem in Bangladesh. Our present study aims to molecularly identify and characterize B. anthracis from three districts of Bangladesh by 16S rRNA gene sequencing. B. anthracis was confirmed in soil, meat, and blood samples using PCR. Anthrax-affected soil (n = 128), blood (n = 1), and meat (n = 2) samples were analyzed using PCR. One of the positive samples was randomly chosen for sequencing, and MEGA5 software was used to generate the phylogenetic tree from the sequencing result. A total of 21 (16.40%) soil samples and all of the blood and meat samples were positive for the presence of bacteria, confirmed by PCR. The 16S rRNA gene of B. anthracis Sirajganj-1 was identical to that of other strains. To fulfill the Sustainable Development Goals, it is important to control zoonotic diseases. Our results may help discover the virulent genes of B. anthracis for future investigation and control this zoonotic disease. Also, a proper awareness of vaccination and effective surveillance system is important to eradicate any kind of zoonotic disease in developing nations. Full article

The present study investigates the prevalence and diversity of Plasmodium and Trypanosoma infections in Allochrocebus solatus, a vulnerable primate species native to Gabon. Using molecular techniques like nested PCR and phylogenetic analysis, we found 34.0% infection rate for malaria parasites infection, 21.3% for Trypanosoma spp., and 12.8% co-infections. Additionally, Hepatocystis was exclusively detected among malaria parasites, while Trypanosoma brucei brucei, T. vivax, and T. congolense were identified. These results underscore the complex host–parasite interactions influenced by captivity and the ecological and immunological consequences of such infections, particularly the increased susceptibility associated with captivity-induced stress. This preliminary study highlights the need for ongoing surveillance to mitigate health risks in primates and prevent potential zoonotic spillovers, providing critical data for conservation efforts. Full article

Device-associated infections (DAIs) are a significant public health concern because of their attributable mortality, along with the extra length of stay and cost. This two- year prospective surveillance study aimed to assess the incidence of DAIs and their clinical impact on four Greek adult medical-surgical Intensive Care Units (ICUs). Centers for Disease Control and Prevention (CDC) definitions were used to diagnose DAIs. Of the 500 patients hospitalized for 12,624 days, 254 (50.8%) experienced 346 episodes of DAIs. The incidence of DAIs was 27.4 episodes per 1000 bed-days. The incidence of ventilator-associated events (VAEs), central line-associated bloodstream infections (CLABSIs), and catheter-associated urinary tract infections (CAUTIs) was 20.5 episodes per 1000 ventilator-days, 8.6 episodes per 1000 central line-days, and 2.5 episodes per 1000 catheter-days, respectively. The most common pathogens isolated were Acinetobacter baumannii (35.7%) and Klebsiella pneumoniae (29.9%). All gram-negative pathogens were carbapenem-resistant. The ICU’s mortality was 44.9% for patients with DAIs and 24.8% for patients without a DAI (attributable mortality 20.1%, p < 0.001), while the mean ICU length of stay was 34.5 days for patients with DAIs and 15.6 days for patients without a DAI (attributable length of stay 18.9 days, p < 0.001). The high incidence of multidrug-resistant pathogens and the attributable length of stay and mortality of DAIs emphasize the need to establish an organized antimicrobial surveillance program and implement a care bundle for DAI prevention in ICUs with personnel educational training, monitoring, and feedback. Full article

Antibiotic resistance is a global health crisis exacerbated by the misuse of antibiotics in healthcare, agriculture, and the environment. In an intensive care unit (ICU), where high antibiotic usage, invasive procedures, and immunocompromised patients converge, resistance risks are amplified, leading to multidrug-resistant organisms (MDROs) and poor patient outcomes. The human microbiome plays a crucial role in the development and dissemination of antibiotic resistance genes (ARGs) through mechanisms like horizontal gene transfer, biofilm formation, and quorum sensing. Disruptions to the microbiome balance, or dysbiosis, further exacerbate resistance, particularly in high-risk ICU environments. This study explores microbiome interactions and antibiotic resistance in the ICU, highlighting machine learning (ML) as a transformative tool. Machine learning algorithms analyze high-dimensional microbiome data, predict resistance patterns, and identify novel therapeutic targets. By integrating genomic, microbiome, and clinical data, these models support personalized treatment strategies and enhance infection control measures. The results demonstrate the potential of machine learning to improve antibiotic stewardship and predict patient outcomes, emphasizing its utility in ICU-specific interventions. In conclusion, addressing antibiotic resistance in the ICU requires a multidisciplinary approach combining advanced computational methods, microbiome research, and clinical expertise. Enhanced surveillance, targeted interventions, and global collaboration are essential to mitigate antibiotic resistance and improve patient care. Full article

Cervical lymphadenitis in children, often caused by bacterial infections, may require surgical drainage if initial antibiotic treatment fails. Identifying factors associated with surgical intervention may aid in treatment decision-making and improve patient outcomes. We assessed the demographic, clinical, and laboratory factors associated with the need for surgical drainage in children diagnosed with cervical lymphadenitis. We conducted a retrospective cohort study of children diagnosed with cervical lymphadenitis or abscesses between 2015 and 2021. Data collected included demographics, clinical presentation, laboratory results, imaging findings, and treatment outcomes. Surgical intervention was compared to the conservative treatment group to identify predictors for drainage. Overall, 201 children were included; 87 (43%) underwent surgical drainage, while 114 (57%) received conservative treatment. In univariate analysis, young age (<3 years), leukocytosis (>15,000/mm³), and longer hospitalization duration (5.6 vs. 3.2 days, p < 0.001) were associated with surgical intervention. Methicillin-susceptible Staphylococcus aureus (MSSA) and methicillin-resistant Staphylococcus aureus (MRSA) were the most common pathogens isolated from abscess cultures. In multivariate analysis, factors associated with surgical drainage included large lymph node size (>3 cm), erythema, and fluctuance in the physical examination and imaging (ultrasound) findings of abscess or phlegmon. Surgical intervention in pediatric cervical lymphadenitis was found to be associated with young age, large lymph nodes, erythema, and abscesses on imaging. Early assessment and recognition of these factors can guide the timely initiation of appropriate treatment, including surgery, when indicated. Full article

Tuberculosis (TB) is an infectious disease caused by bacteria that primarily target the lungs. The transmission of this disease occurs through the air in the form of droplet nuclei. Unfortunately, there has been an emergence of resistance to strains of such infections, such as multidrug- as well as extensively drug-resistant strains. Healthcare workers (HCWs) are particularly vulnerable to contracting TB due to their direct contact with patients. This study aims to evaluate the knowledge, attitude, and practices among Lebanese healthcare workers towards TB and its resistant forms, particularly multidrug-resistant TB (MDR-TB) and extensively drug-resistant TB (XDR-TB). This study is a cross-sectional, descriptive, questionnaire-based research study that was conducted on HCWs in Lebanon. A total of 517 HCWs were included in this study. The findings displayed that 48.52% of HCWs had good knowledge of TB and MDR-TB/XDR-TB, 49.52% had average knowledge, and 2.13% had bad knowledge. Moreover, only 16.25% had a good attitude, 71.92% had an average attitude, and 11.8% had a bad attitude. Furthermore, only 14.7% had good practices, 54.74% had average practices, and 30.56% had bad practices. Having a history of testing for TB was found to be related to increased attitude. Also, the history of having TB-infected family members was found to be linked to both increased attitude and practice scores. Moreover, this study highlights the idea that high knowledge scores do not mean high attitude or high practices scores. On the same note, acceptable attitude scores do not inflict acceptable practice scores. The findings of this study showed that there is an overall good knowledge regarding TB, MDR-TB, and XDR-TB, average attitude, and average-to-bad practices. Gaps are seen in all sectors, even knowledge, especially with matters related to the diagnosis of MDR-TB/XDR-TB and its treatment duration. Also, the attitude section revealed a gap in the understanding of the modes of transmission of such an infection. Full article

Laboratory-acquired infections (LAIs) pose significant risks to laboratory personnel, public health, and the environment, despite the implementation of biosafety measures. This study provides a comprehensive analysis of global LAIs reported from 1974 to 2024, identifying trends, causes, and pathogen distributions to address gaps in biosafety knowledge. A systematic literature review was conducted using databases such as PubMed, Cochrane, Google Scholar, and the American Biological Safety Association (ABSA). A total of 234 studies meeting strict inclusion criteria were analyzed. Bacterial pathogens accounted for 58.6% of reported incidents, followed by viruses at 36.1%. Procedural errors and accidents were the predominant causes of LAIs, with Brucella spp. being the most frequently reported pathogen, primarily in China. Temporal trends indicated a decline in incidents coinciding with the implementation of international biosafety regulations. However, disparities in incident reporting and compliance remain evident across countries. This study underscores the urgent need for a global regulatory framework, mandatory biosafety audits, a centralized incident database, and standardized training for high-containment laboratory personnel. Enhancing global collaboration, transparency in research, and adherence to ethical standards will further reduce LAI risks and strengthen public health security worldwide. Full article

Since the nasopharynx serves as an ecological niche for Streptococcus pneumoniae, Corynebacterium spp., Haemophilus influenzae, Moraxella catarrhalis, etc., colonization is influenced by antimicrobial treatments, host immune responses, viral infections, and vaccines, often leading to local and systemic infections. We aimed to investigate the patterns of nasopharyngeal colonization and antimicrobial susceptibility of bacterial isolates in Bulgarian individuals under 20 years of age presenting with acute, protracted, and chronic cough. We analyzed 1383 samples using conventional culture methods, MALDI-TOF MS, antimicrobial susceptibility testing, and genetic analyses for Bordetella pertussis and Mycoplasma spp. Among 896 isolates, H. influenzae was the most prevalent (26.23%), followed by M. catarrhalis (23.55%), S. pneumoniae (22.54%), and S. pyogenes causing 7.59% of infections. In children (0–10 years), M. catarrhalis (198 isolates) and H. influenzae (142 isolates) were the most common pathogens, followed by S. pneumoniae (73 isolates), while in those aged 10–20 years, S. pneumoniae was the most common isolate (129), followed by H. influenzae (93) and M. pneumoniae (21). Colonization in children and young adults serves as a reservoir for pathogen transmission to adults, highlighting its significant public health implications. Monitoring bacterial colonization and resistance patterns remains essential to inform targeted prevention and treatment strategies. Full article

Diabetic foot ulcers (DFUs) are a multifactorial pathophysiologic condition that occurs in patients with diabetes mellitus (DM). Approximately 9.1 to 26.1 million people are affected by DFUs annually. This condition can lead to progressive foot infections and, ultimately, foot amputation. Various microbes contribute to DFUs, including methicillin-resistant Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli can form biofilms composed of complex matrices that create a protective shield around the microorganisms, enhancing their survival and resistance to treatment. Biofilm formation is a critical virulence factor directly associated with the onset and persistence of DFUs. It not only complicates the clinical management of these ulcers but also facilitates antibiotic resistance, necessitating a comprehensive approach to treatment. Effective management strategies must therefore target biofilm formation, and the virulence factors associated with these pathogens. By addressing these elements, conventional antibiotics can be rendered more effective in treating diabetic foot ulcers. This approach aims not only to promote wound healing but also to address underlying causes and prevent further complications. This article seeks to highlight the significance of biofilm formation in DFUs, explore methodologies for studying this condition, as well as discuss demographic considerations and treatment options. Full article

In our previous study, Lentzea sp. JNUCC 0626 was isolated from Hwasun Gotjawal on Jeju Island, and its melanogenic effects were confirmed in B16F10 melanoma cells through the identification of 1-acetyl-β-carboline. In this study, we conducted a comprehensive taxonomic characterization of Lentzea sp. JNUCC 0626, including enzymatic activities, carbohydrate metabolism, growth conditions, and cellular composition. Major fatty acids identified were iso-C16:0, iso-C15:0, and C15:0 anteiso, with polar lipids such as diphosphatidylglycerol, phosphatidylethanolamine, and several unidentified lipids. Ubiquinone Q-9 was determined as the predominant respiratory quinone. Enzymatic activity analysis (API ZYM) showed alkaline phosphatase, esterase (C4), esterase lipase (C8), and leucine arylamidase activities, while carbohydrate metabolism analysis (API 50CHB) indicated acid production from esculin alone. Complete genome sequencing revealed a 10,602,950 bp linear chromosome and a 177,940 bp plasmid. This plasmid encodes essential plasmid-related genes, including a Type IV secretion system and ParA proteins critical for plasmid transfer and stability. These findings suggest that the plasmid in Lentzea sp. JNUCC 0626 could be utilized for developing host–vector systems to facilitate the combinatorial biosynthesis of novel bioactive compounds. Comparative genomic analysis identified Lentzea pudingi CGMCC 4.7319 as the closest relative, but significant genetic divergence (dDDH 46.7%, ANI 88.02%) strongly supports the classification of Lentzea sp. JNUCC 0626 as a novel species. AntiSMASH analysis revealed 34 biosynthetic gene clusters (BGCs), highlighting the strain’s capacity to produce diverse bioactive compounds. Finally, the JNUCC 0626 extract exhibited concentration-dependent NO inhibition in LPS-stimulated RAW 264.7 cells, demonstrating significant anti-inflammatory activity. This suggests that the secondary metabolites inferred from genomic analysis may contribute to these observed bioactivities. Full article

One of the most dangerous and difficult side effects to treat after total hip arthroplasty (THA) is periprosthetic or superficial site infection. Blood and synovial fluid biomarkers have recently come into focus in addition to conventional systemic indicators of inflammation in order to assess their potential utility in the diagnosis of infections. Long pentraxin 3 (PTX3) appears to be a sensitive biomarker of acute-phase inflammation. The purpose of this study is to determine plasma PTX3 in patients undergoing THA and compare its trend with other common serum markers, such as CRP, D-dimer, procalcitonin, and ESR up to 30 days post-operatively. Patients with hip arthritis or avascular necrosis of the femoral head were consecutively enrolled in a single-center study. Each patient underwent blood testing for ESR, CRP, procalcitonin, D-dimer, and PTX3 levels before surgery and at 1, 3, 5, 15, and 30 days after THA. PTX3 was measured using the ELISA method. Other markers’ values and trends were compared with PTX3’s. A total of 50 patients met our inclusion criteria. When different trends were evaluated, PTX3 was found to have a trajectory and sensitivity comparable to other inflammatory markers. Notably, PTX3 changed more quickly than the other markers, with a sharp increase immediately post-operatively, followed by normalization at the 5-, 15-, and 30-day follow-ups, corresponding to the resolution of the inflammatory condition. However, 30 days post surgery, no patients exhibited signs or symptoms of early prosthetic infection. PTX3 is confirmed as a reliable and promising serum biomarker for tracking the level of inflammation in patients undergoing total hip replacements. Blood PTX3 values rise even more rapidly than CRP and procalcitonin and then quickly return to normal values when the inflammatory process resolves. One of the primary barriers to PTX3’s inclusion in routine studies on early periprosthetic infections is the waiting period for PTX3 sample analysis. Full article

Non-typhoidal Salmonella (NTS) infection poses a significant public health challenge globally, particularly in developing countries like India. NTS, predominantly represented by S. enterica serovars, is a major cause of intestinal and extra-intestinal infections. This review provides a comprehensive overview of longitudinal analyses of the prevalence of NTS in different regions of India encountered in the last 20 years and their antimicrobial resistance patterns. We followed several research investigations published during 2000–2024 to examine the incidence and prevalence of different serovars of NTS in several parts of India and followed published articles on NTS showing resistance to different antibiotics. We pointed out NTS serovars, which are predominantly isolated in various human and non-human sources, as observed in several investigations conducted in different regions of India. Our analysis revealed that, among serovars detected from various sources, S. Typhimurium is the most predominant one occurring across both human and non-human sources, followed by S. Enteritidis and S. Weltevreden. The occurrence of similar serovars of Salmonella in both human and non-human sources may be due to zoonotic transmission between animals and humans. Extensive research conducted across many geographic locations reveals that NTS isolates exhibit resistance to several antibiotics, with multidrug-resistance (MDR) being more common. These MDR strains basically show resistance to three or more classes of antibiotics, including critically important antimicrobials such as nalidixic acid, ciprofloxacin, and third-generation cephalosporins. Temporal trends suggest an alarming increase in resistance to these antibiotics, particularly in serovars such as S. Typhimurium and S. Enteritidis. Overall, the current article sheds light on the urgent need for surveillance, judicious antibiotic use, and the development of alternative treatment strategies to combat the rising tide of antibiotic-resistant NTS strains. Full article

The rising global prevalence of obesity and its associated metabolic disorders highlights the urgent need for innovative, sustainable interventions. Probiotics, as modulators of gut microbiota, have emerged as promising agents in weight management by influencing metabolic health. This mini-review explores the role of probiotics in modulating gut microbiota to support energy metabolism, appetite regulation, and fat storage. Evidence underscores the strain-specific benefits of probiotics, such as Lactobacillus gasseri SBT2055, Bifidobacterium breve B-3, and Akkermansia muciniphila, in reducing visceral fat, improving glucose metabolism, and mitigating obesity-related inflammation. The mechanisms underlying these effects include short-chain fatty acid (SCFA) production, modulation of appetite-regulating hormones, and improvements in gut barrier integrity. While the findings are promising, variability in outcomes highlights the importance of tailored probiotic interventions and underscores the need for standardized methodologies in future research. By addressing these challenges, probiotics can serve as integral components of personalized nutrition strategies, advancing both metabolic health and public health objectives. Full article

Microbial succession on urban masonry surfaces is a critical yet understudied aspect of environmental microbiology, with implications for public health within the One Health framework. This study investigated how building age, orientation, and vegetative cover influence microbial diversity on masonry, metal, and glass substrates at the University of La Verne, California. Biophysical characterizations were conducted, and microbial communities were analyzed using morphospecies richness and DNA sequencing. Significant variation in microbial species richness (χ² = 20.3882, p = 0.0011) and diversity (Fisher’s LSD, p < 0.05) was observed. Masonry surfaces exhibited the highest microbial diversity, with a mean richness of 23 morphospecies compared to 14 on metal and 12 on glass. Penicillium fungi dominated masonry sites, comprising 45% of colonies, while Pseudomonas and Klebsiella were more prevalent on metal and glass surfaces (35% and 28%, respectively). Microbial succession did not follow a linear progression but showed non-sequential shifts influenced by local conditions. The abundance of Penicillium, known for antibiotic production, raises concerns about spreading antibiotic resistance genes. Opportunistic pathogens further highlight potential health risks. These findings underscore the importance of understanding primary successional processes in urban environments to manage microbial communities and mitigate public health risks. Full article

The COVID-19 pandemic has highlighted several cardiovascular complications, including myocarditis, which can be a significant cause of sudden cardiac death in young people. SARS-CoV-2 infection can cause cardiac muscle inflammation through direct mechanisms, such as viral invasion of myocardial cells, and indirect mechanisms, such as the systemic inflammatory response. Myocarditis can lead to life-threatening electrical dysfunctions and arrhythmias. Although post-infection myocarditis is more common, rare cases of post-vaccination myocarditis have also been reported, especially with mRNA vaccines. However, these post-vaccination cases tend to be mild and self-limiting, with a good response to treatment. Despite the associated risks, the benefits of vaccination far outweigh the risks, significantly reducing the incidence and severity of COVID-19 infections and related heart complications. It is crucial to continue surveillance and research to better understand the association between COVID-19, myocarditis and sudden cardiac death in the young and improve prevention and intervention strategies. In this literature review, we analyzed the pathogenetic mechanisms and histological features of myocarditis associated with COVID-19 and its vaccination, and focused on the correlation with sudden cardiac death. Full article

The safety precautions required for certain pathogens are different in clinical laboratories and patient-facing healthcare settings, causing confusion for laboratorians and infection preventionists. The current review aims to summarize information from reputable Government of Canada guidance commonly used in clinical laboratories in Canada, including the Government of Canada Human Pathogens and Toxins Act and Regulations, the ePATHogen—Risk Group Database, biosafety directives and advisories, Transportation of Dangerous Goods Regulations, and the Canadian Biosafety Standard (2022). Guidelines from the Centers for Disease Control and Prevention’s (CDC) Biosafety in Microbiological and Biomedical Laboratories (2020), Clinical and Laboratory Standard Institution’s (CLSI) M29 Protection of Laboratory Workers from Occupationally Acquired Infections (2014), and Association of Public Health Laboratories’s Biothreat Agent Bench Cards for the Sentinel Laboratory (2018) were also used to supplement specific details. In comparison, information regarding infection prevention and control practices in patient-facing healthcare settings was summarized: Public Health Agency of Canada: Routine Practices and Additional Precautions for Preventing the Transmission of Infection in Healthcare Settings (2017) and CDC Infection Control Guideline for Isolation Precautions: Preventing Transmission of Infectious Agents in Healthcare Settings (2007). Contrasting levels of precautions exist between laboratories and patient-facing settings, especially for endemic fungi and certain security-sensitive biological agents. Acknowledging this contrast may facilitate risk communication relative to the counterparts to minimize the threat and disease effects and ensure public confidence. Full article

Cervical tuberculosis is a rare form of genital tuberculosis. A case of a 73-year-old woman who presented with cervical wall thickening on magnetic resonance imaging, suggesting an invasive malignant neoplasm, is documented. Cervical cone excision was performed for histopathological study. Microscopy showed epithelioid granulomas, without appreciable caseous necrosis, in the wall of the uterine cervix, associated with erosion of the overlying cervical mucosa. Histochemical stains for microorganisms (Ziehl–Neelsen, Grocott, and Warthin–Starry) were negative. Immunohistochemistry for Treponema pallidum revealed scarce, spiral-shaped bacilli, which raised the diagnostic possibility of secondary syphilis. The serological study for syphilis was negative, however. Polymerase chain reaction (PCR) tests for Mycobacterium tuberculosis and Treponema pallidum were performed in the formaldehyde-fixed, paraffin embedded tissue and resulted positive for Mycobacterium tuberculosis and negative for Treponema pallidum, confirming the diagnosis of cervical tuberculosis. Our objective was to report a rare case of cervical tuberculosis, discussing the advantages and limitations of complementary techniques used in the pathological diagnosis of infectious agents and highlighting diagnostic pitfalls. In conclusion, correct microbiological diagnosis requires the implementation of integrated workflows employing complementary techniques in a multidisciplinary setting to improve the accuracy of histopathological examination in infectious diseases. Full article

Viruses transmitted by arthropods (arboviruses) pose a global public health threat. Sporadic cases or outbreaks caused by West Nile virus, Crimean–Congo haemorrhagic fever virus, tick-borne encephalitis virus, and phleboviruses are often reported in Europe. Recently, they expanded their distribution in geographic areas where they had never been observed before, while tropical viruses, like Dengue, Chikungunya, and Zika, started to cause autochthonous cases and outbreaks following the return of viraemic travellers from endemic countries. The primary or secondary vectors of these viruses are established in Europe, and the incidence of arboviral diseases is expected to increase due to several anthropogenic and/or environmental factors (mainly climate change, which affects the survival and amplification of the arthropod vectors). This is an update on the emerging arboviruses in Europe, associated challenges, and future perspectives. Full article