MicrobiologyOpen[JOURNAL]
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200 papers
Detection of Among Carbapenem-Resistant Acinetobacter baumannii Isolated From Intensive Care Units of a Tertiary Care Hospital in Pakistan.
Waseem H, Ullah I, Ahmad S … +3 more , Mirza IA, Aleem B, Iqbal S
Microbiologyopen · 2026 Aug · PMID 42402810 · Publisher ↗
Carbapenem-resistant Acinetobacter baumannii (CRAB) has been designated a top-priority critical pathogen by the World Health Organization, and the CDC has also classified it as a serious and immediate public health threa...
Carbapenem-resistant Acinetobacter baumannii (CRAB) has been designated a top-priority critical pathogen by the World Health Organization, and the CDC has also classified it as a serious and immediate public health threat. The Cross-sectional study was conducted to detect the gene among carbapenem-resistant Acinetobacter baumannii isolated from clinical specimens in intensive care units. The study was conducted at the Department of Microbiology, Institute of Pathology and Diagnostic Medicine, Khyber Medical University, from January 2024 to December 2024. Phenotypically confirmed Carbapenem-resistant Acinetobacter baumannii isolates were genotypically verified via detection, then screened for using polymerase chain reaction, and PCR mapping was done for the upstream insertion of ISAba1. gene with an upstream insertion of ISAba1 is detected in all 52 (100%) isolates. ST19 is the most commonly identified ST, accounting for 31 (59.6%), followed by ST2 14 (26.9%) and ST1 7 (13.4%). Consequently, these findings emphasize the implementation of targeted infection control measures and routine surveillance screening within high-risk ICU environments to mitigate further transmission.
Oral Microbial and Metabolic Alterations in Patients With Oral Lichen Planus Concomitant With Type 2 Diabetes Mellitus.
Ren X, Li K, Kong X … +3 more , Li J, Hua H, Li C
Microbiologyopen · 2026 Aug · PMID 42396953 · Full text
The present study aimed to comprehensively characterize the oral microbiome and metabolic profiles in patients with oral lichen planus (OLP) concomitant with type 2 diabetes mellitus (T2DM), and to explore the potential...
The present study aimed to comprehensively characterize the oral microbiome and metabolic profiles in patients with oral lichen planus (OLP) concomitant with type 2 diabetes mellitus (T2DM), and to explore the potential mechanisms driving the co-occurrence. This was a cross-sectional observational study. A total of 60 participants were enrolled, including 20 normal controls, 20 patients with OLP alone (OLP group), and 20 patients with both OLP and T2DM (OLP_DM group). Salivary samples were subjected to 16S rRNA sequencing and untargeted metabolomics to assess microbiological and metabolic differences across the groups. Spearman's correlation analysis was used to evaluate associations between clinical characteristics and microbial or metabolic features. Alpha diversity (Chao1 index) was significantly reduced in both disease groups compared to the controls, while beta diversity analysis revealed no remarkable separation among groups. At the genus level, the abundance of Pseudomonas was elevated in the OLP_DM group relative to both the OLP and control groups, and positively correlated with lesion severity. Metabolomic analysis revealed significantly lower levels of limonin and higher levels of thymine and epinephrine in the OLP_DM group compared to the OLP. Limonin was negatively correlated with lesion severity, whereas thymine and epinephrine showed positive correlations with both lesion severity and pain scores. The study provides comprehensive evidence of oral microbial dysbiosis and metabolic disturbances in patients with OLP concomitant with T2DM. The findings suggest an interplay between specific bacterial populations and metabolic alterations in the progression and severity of OLP concomitant with diabetes.
De novo or Salvage? Nucleotide Availability as a Driver of Bacterial Adaptation and Virulence.
Joshi R, McEwan AG, Kappler U
Microbiologyopen · 2026 Aug · PMID 42393866 · Full text
Bacterial pathogens rely on the constant availability of purine and pyrimidine nucleotides to facilitate replication, growth, and virulence and to sustain energy metabolism and nucleotide-based signaling. The capacity to...
Bacterial pathogens rely on the constant availability of purine and pyrimidine nucleotides to facilitate replication, growth, and virulence and to sustain energy metabolism and nucleotide-based signaling. The capacity to switch between de novo synthesis and salvage pathways underpins much of their metabolic flexibility and also regulates access to different human body niches, where nucleobase availability varies significantly between extracellular fluids, mucosal surfaces, inflamed tissues, and intracellular compartments. However, adaptation to specific host niches can result in the loss of de novo nucleotide biosynthesis pathways, increasing bacterial dependence on nucleobase/nucleoside salvage. Many intracellular pathogens lack de novo synthesis pathways, making purine or pyrimidine salvage not an optional, but an essential process where host nucleotide reserves are critical to bacterial survival. Because of their central role in bacterial metabolism, enzymes, transporters, and regulatory networks involved in purine and pyrimidine metabolism represent potential targets for therapeutic interventions. This review summarizes the current knowledge of purine and pyrimidine metabolism in bacterial pathogens, including the abundance of these compounds in different host niches, tissue-specific fitness strategies, and bacterial targets for further development of innovative antibacterials.
One Health Insights From Pteropus medius: Nipah Virus Spillover, Microbiota, and Antimicrobial Resistance.
Chowdhury P, Khan SMT, Roy S … +1 more , Faruk MSA
Microbiologyopen · 2026 Aug · PMID 42387669 · Full text
Pteropus medius is a major reservoir of Nipah virus (NiV), a zoonotic pathogen responsible for recurrent fatal encephalitis outbreaks in Bangladesh. Human infections are primarily associated with consuming raw date palm...
Pteropus medius is a major reservoir of Nipah virus (NiV), a zoonotic pathogen responsible for recurrent fatal encephalitis outbreaks in Bangladesh. Human infections are primarily associated with consuming raw date palm sap contaminated with bat excreta. Beyond viral spillover, growing evidence suggests that bat-associated microbiota and guano are potential reservoirs of antimicrobial resistance (AMR), contributing to the environmental dissemination of resistant bacteria and resistance genes. This narrative literature review examined the relationship among NiV spillover, bat microbiota, and AMR within a One Health framework. A structured literature search was conducted using PubMed, Scopus, Web of Science, ScienceDirect, and Google Scholar to identify relevant peer-reviewed studies published between 2006 and 2025. The reviewed evidence indicates that Pteropus medius populations harbor clinically important resistant bacteria, including ESBL-(Extended-Spectrum Beta-Lactamase) producing Escherichia coli, Salmonella spp., and methicillin-resistant Staphylococcus spp. In addition, recent studies indicate that bat roosts near agricultural lands, wastewater discharge sites, and peri-urban settlements may facilitate bidirectional exchange of ARGs among wildlife, livestock, and humans. Habitat fragmentation, wastewater contamination, urbanization, agricultural intensification, and increased human-wildlife interactions were identified as major drivers facilitating both NiV spillover and AMR dissemination. Overall, the literature demonstrates a significant ecological association among anthropogenic environmental disturbance, zoonotic spillover risk, and the emergence of antimicrobial resistance in bat-associated systems. These findings highlight the importance of integrated One Health surveillance and environmental management strategies to mitigate future zoonotic and AMR threats in Bangladesh.
Seasonal Restructuring of Microbial Communities and Resistomes in the Shitalakshya River, Bangladesh Revealed by Shotgun Metagenomics.
Haque ME, Rahman MS, Sultana M … +1 more , Begum A
Microbiologyopen · 2026 Aug · PMID 42385223 · Full text
Urban rivers supplying drinking water face mounting pollution and AMR threats. We combined shotgun metagenomics with physicochemical analysis to investigate microbial community and resistome dynamics in Bangladesh's Shit...
Urban rivers supplying drinking water face mounting pollution and AMR threats. We combined shotgun metagenomics with physicochemical analysis to investigate microbial community and resistome dynamics in Bangladesh's Shitalakshya River, a drinking water source under increasing pollution pressure, during early and peak dry seasons. Peak dry season water quality deteriorated markedly, characterized by hypoxia and elevated nutrient and organic carbon levels, which drove pronounced restructuring of the river microbiome. A distinct shift occurred from Myroides dominance toward a more diverse assemblage enriched in pollution-tolerant and opportunistic genera, notably Comamonas, Brevundimonas, Tissierella, and Aeromonas. Metagenomic profiling revealed a diverse resistome encompassing antibiotic, metal, and biocide resistance genes. Although overall antibiotic resistance gene abundance declined slightly, metal resistance genes increased more than twofold, with strong enrichment of mercury resistance determinants such as merA. Concurrent increases in multidrug efflux pump genes suggested potential co-selection driven by metal and chemical stressors. These findings indicate that dry-season pollutant concentration reshapes both microbial communities and resistance profiles through non-antibiotic selective pressures. Despite limited sampling, this study provides a baseline metagenomic snapshot of antimicrobial resistance dynamics in a climate-stressed urban river system, offering vital insights for pollution abatement and the safeguarding of drinking water safety.
Emergence of Ceftazidime-Avibactam-Induced KPC Variants (KPC-25/127) in Intracranial Infection and Implications for Clinical Management.
Lei K, Tian Y, Xiong C … +6 more , Lei J, Chen D, Bai X, Abdul-Aziz MH, Xie J, Liu Z
Microbiologyopen · 2026 Aug · PMID 42385193 · Full text
The emergence of novel Klebsiella pneumoniae carbapenemase (KPC) variants contributing to clinical treatment failure poses a substantial threat to public health. To inform the clinical management of infections caused by...
The emergence of novel Klebsiella pneumoniae carbapenemase (KPC) variants contributing to clinical treatment failure poses a substantial threat to public health. To inform the clinical management of infections caused by KPC-variant-harboring K. pneumoniae, this study reports the complex evolutionary trajectory of ceftazidime-avibactam (CAZ-AVI)-resistant KPC-variant-harboring K. pneumoniae in a single patient during CAZ-AVI treatment. Three KPC-producing K. pneumoniae (KPC-KP) isolates were obtained from a patient with K. pneumoniae infection who received sequential treatment with imipenem followed by CAZ-AVI. Isolate K2, harboring bla, exhibited carbapenem resistance. After 12 days of CAZ-AVI administration, isolate K25 (carrying bla) showed CAZ-AVI resistance but remained susceptible to imipenem. In contrast, isolate K127 (harboring bla firstly identified by our group), recovered after combined CAZ-AVI and imipenem therapy, displayed dual resistance to both CAZ-AVI and carbapenems; this carbapenem resistance was attributed to outer membrane protein mutations combined with bla overexpression. Analysis of the genetic regions revealed that all subtypes were located within a conserved genetic background: IS26-ISKpn8-bla-ΔISKpn6-ΔtnpR-Tn1721. Cloning and heterologous expression of the KPC variants, followed by enzymatic kinetic analyses and minimum inhibitory concentration (MIC) determinations, confirmed that the variants altered the MICs of CAZ-AVI and carbapenems. Compared with the KPC-2 protein, both variant proteins exhibited reduced hydrolytic activity against ceftazidime. Additionally, the half-maximal inhibitory concentration (IC) of avibactam against the KPC variants was significantly higher than that of the wild-type KPC-2 protein. These results indicate that the KPC variant proteins have low affinity for avibactam, thereby reducing susceptibility to this inhibitor.
Occurrence of Antimicrobial Resistance in Kocuria rhizophila Bacteria Isolated From Salmo munzuricus (Teleostei: Salmonidae) Samples in Natural Resources.
Kar B
Microbiologyopen · 2026 Aug · PMID 42370482 · Full text
Global warming and environmental pollution trigger the emergence of antimicrobial-resistant (AMR) opportunistic pathogens in the aquatic microflora. This study aimed to determine the characterization and AMR profile of t...
Global warming and environmental pollution trigger the emergence of antimicrobial-resistant (AMR) opportunistic pathogens in the aquatic microflora. This study aimed to determine the characterization and AMR profile of the opportunistic pathogen Kocuria rhizophila isolated from the tissues of Salmo munzuricus (Munzur trout), an endemic species. Samples collected from the Munzur River were identified using morphological and molecular (16S rDNA) methods; bacterial isolates were characterized by MALDI-TOF and sequencing. The resistance status against 11 different antibiotics was analyzed with the Kirby-Bauer method. The findings revealed that the isolates (with 99.51% accuracy as K. rhizophila) showed full resistance to Penicillin G (p < 0.01) and were moderately sensitive to gentamicin and tetracycline. High sensitivity to amoxicillin and ampicillin was detected. These findings demonstrate that even in natural environments, the fish microbiome in wild endemic populations can be susceptible to the development of AMR in response to environmental changes. Therefore, determining the resistance of opportunistic pathogens in wild fish species such as Salmo munzuricus to different classes of antibiotics and studying their spread is extremely important for natural ecosystems.
Predicted Functional Potentials of Bacterial Communities in Fermented Maize Products From Ghana, Nigeria, and Benin via 16S rRNA Amplicon Sequencing and PICRUSt2.
Addy HPK, Amedorme D, Osei-Poku P … +1 more , Kwarteng A
Microbiologyopen · 2026 Jun · PMID 42359485 · Full text
Fermented maize products are integral to the diets of many African communities. Despite their cultural significance and health benefits, little is known about the metabolic potential of their microbial populations. This...
Fermented maize products are integral to the diets of many African communities. Despite their cultural significance and health benefits, little is known about the metabolic potential of their microbial populations. This study utilized 16S rRNA amplicon sequencing data from the NCBI to characterize the functional capabilities of microbiomes in six maize-based fermented foods. Quality assessment and taxonomic classification were performed using QIIME2 with the SILVA 138 database, while functional predictions were generated with PICRUSt2 and analyzed in R. Taxonomic profiling revealed that Firmicutes dominated all samples, reaching peak abundance in Mawe (94.9%) and S37_Fermented_Maize (91.4%). Proteobacteria were elevated in S19_Fermented_maize (up to 36.5%) and S38_Dehulled_Maize (16.0%). At the genus level, Lactobacillus was most abundant in S5_Mawe (82.2%) and S6_Mawe (79.6%), while Acetobacter peaked in S19_Fermented_maize (32.7%). Regarding functional predictions, Lactobacillus appeared to drive key KEGG Orthologs and pathways, specifically ABC transporters, transcriptional regulation, and DNA replication mechanisms. In contrast, Weissella and Streptococcus contributed notably to peptide/nickel transport, L-lactate dehydrogenase (EC 1.1.1.27), and nucleotide biosynthesis. Acetobacter was prominent in Ogi, showing a connection with site-specific methylation (EC 2.1.1.72) and phospholipid synthesis (PHOSLIPSYN-PWY). Notably, commercial Mawe samples exhibited higher predicted activities related to transposase activity (K07496), energy metabolism, and peptidoglycan maturation (PWY0-1586). These findings demonstrate that while traditional fermentation processes maintain a consistent set of metabolic functions predominantly driven by Lactobacillus, distinct variations exist depending on product type and production approach. These predicted functions provide a baseline for further experimental validation of the metabolic contributions of microbial communities in fermented maize products.
Carbapenem-Resistant Gram-Negative Bacilli in Mauritania: A Major Public Health Threat.
Sid'Ahmed FA, Abbe AM, Salem ML
Microbiologyopen · 2026 Jun · PMID 42351268 · Full text
Carbapenem-resistant Gram-negative bacilli (CR-GNB) are an emerging public health threat due to limited treatment options. This retrospective study investigated the epidemiology and resistance patterns of CR-GNB isolated...
Carbapenem-resistant Gram-negative bacilli (CR-GNB) are an emerging public health threat due to limited treatment options. This retrospective study investigated the epidemiology and resistance patterns of CR-GNB isolated at the National Hospital Center of Nouakchott, Mauritania, between January 2020 and June 2022. Among 565 Gram-negative bacilli isolates, 25 were carbapenem-resistant, corresponding to a prevalence of 4.42%. Klebsiella pneumoniae and Escherichia coli were the most frequently identified species, and most isolates were recovered from urine samples. High resistance rates were observed to beta-lactams and fluoroquinolones, whereas colistin, tigecycline, and amikacin retained good activity. Although the prevalence remains relatively low, continuous surveillance and appropriate infection control and antimicrobial stewardship measures are required to prevent the spread of carbapenem resistance.
Essential Oils and Their Multifunctional Activities Against Pseudomonas aeruginosa: Current Evidence and Perspectives.
Novello G, Bona E, Petroselli M … +13 more , Bazzano C, Chiesa S, Gaggero T, Gaglio G, Magnani G, Pampaloni Pasetti A, Repetto S, Rotella E, Topino A, Serra E, Vidali M, Zonca S, Gamalero E
Microbiologyopen · 2026 Jun · PMID 42350929 · Full text
Pseudomonas aeruginosa is an opportunistic pathogen responsible for acute and chronic infections and is characterized by a remarkable ability to develop antibiotic resistance. This has prompted increasing interest in alt...
Pseudomonas aeruginosa is an opportunistic pathogen responsible for acute and chronic infections and is characterized by a remarkable ability to develop antibiotic resistance. This has prompted increasing interest in alternative or complementary antimicrobial strategies, including the use of essential oils (EOs), which are complex mixtures of plant-derived volatile compounds with documented biological activities. This review aims to summarize and discuss the current evidence on the antimicrobial, antibiofilm, and anti-virulence activities of EOs against P. aeruginosa, with particular emphasis on their mechanisms of action, synergistic interactions with antibiotics, and limitation to the possible clinical applicability. A large number of studies, mainly conducted in vitro, indicate that EOs and their major constituents can impair P. aeruginosa viability and pathogenicity through multiple mechanisms. In addition, several EOs or purified terpene components exhibit synergistic effects when combined with conventional antibiotics, enhancing antimicrobial efficacy. However, in vivo evidence remains limited, largely restricted to topical infection models, while clinical studies in humans are currently lacking. Significant challenges related to chemical variability, toxicity, safety, standardization, and regulatory classification also emerge from the literature. Although EOs show considerable promise as antimicrobial and anti-virulence agents against P. aeruginosa, their current role should be viewed primarily as adjunctive or alternative strategies rather than as standalone systemic therapies. Future progress will depend on the development of standardized and safer formulations, advanced delivery systems, and well-designed in vivo and clinical studies.
Genome-Guided Discovery of Vaccine Targets for a Multi-Epitope Construct Against Multidrug-Resistant Enterobacter cloacae.
Aljumaa MA, Al-Joufi FA, Nabi G … +1 more , Sandrine MNY
Microbiologyopen · 2026 Jun · PMID 42338316 · Full text
Multidrug-resistant (MDR) Enterobacter cloacae has emerged as a serious public health threat, particularly in hospital settings, due to its ability to cause severe infections and rapidly acquire antibiotic resistance. Th...
Multidrug-resistant (MDR) Enterobacter cloacae has emerged as a serious public health threat, particularly in hospital settings, due to its ability to cause severe infections and rapidly acquire antibiotic resistance. The limited effectiveness of current antibiotics highlights the urgent need for alternative preventive strategies such as vaccination. In this study an immunoinformatics-based approach was employed to design a multi epitope vaccine (MEV) targeting the conserved and surface exposed outer membrane protein A (OmpA) of MDR E. cloacae. The entire proteome was screened to identify suitable vaccine targets based on antigenicity, allergenicity and homology analysis. Highly immunogenic B-cell, MHC class I and MHC class II epitopes were predicted and selected for vaccine construction. The selected epitopes were linked using suitable linkers, while the 50S ribosomal L7/L12 protein was incorporated as an adjuvant. The designed MEV construct was evaluated through structural modelling, molecular docking with TLR4 receptor, immune simulation, population coverage analysis, codon optimization and in silico cloning. The vaccine candidate demonstrated strong antigenicity, non-allergenicity, structural stability, and favourable physicochemical properties. Population coverage analysis indicated 99.92% global coverage. Molecular docking revealed stable and energetically favourable interactions with TLR4, while immune simulation predicted strong humoral and cellular immune responses, including memory cell formation and a Th1-biased cytokine profile. Codon optimization indicated favorable expression potential in an E. coli. Overall, the proposed MEV predicted a promising, safe, stable and broadly protective vaccine candidate against MDR Enterobacter cloacae.
Facing Antimicrobial Resistance and Virulence in Streptococcus agalactiae During Late Pregnancy: Evaluation of Lactobacilli as a Supportive Approach.
Tagueha AD, Radocchia G, Scribano D … +14 more , Lo Scalzo M, Panella G, Schippa S, Gherardi G, Creti R, Marani I, Alfarone G, Imperi M, Marazzato M, Nencioni L, Checconi P, Limongi D, Palamara AT, Ambrosi C
Microbiologyopen · 2026 Jun · PMID 42338158 · Full text
Streptococcus agalactiae (Group B streptococcus, GBS) remains a major cause of neonatal sepsis and meningitis, despite the success of intrapartum antibiotic prophylaxis. However, the rising trend of antimicrobial resista...
Streptococcus agalactiae (Group B streptococcus, GBS) remains a major cause of neonatal sepsis and meningitis, despite the success of intrapartum antibiotic prophylaxis. However, the rising trend of antimicrobial resistance and the emergence of hypervirulent lineages highlight the need for complementary, innovative prophylactic strategies. This study aimed to characterize the resistance and virulence repertoire of colonizing GBS isolates and to assess the antagonistic potential of selected Lactobacillus strains under conditions mimicking the vaginal niche. We performed integrated phenotypic, genotypic, and functional analysis of 31 clinical GBS isolates collected during routine pre-partum screening, focusing on antimicrobial susceptibility, hemolytic and aggregation phenotypes, capsular serotypes, pilus island profiles, and virulence genes. The collection included MDR isolates, strains exhibiting inducible clindamycin resistance and high-level gentamicin resistance, as well as hypervirulent ST-17 related lineages, with marked heterogeneity in β-hemolytic activity and aggregation phenotypes linked to specific combinations of capsule, pilus, and virulence genes. In co-culture experiments with HeLa cells, individual Lactobacillus strains exerted strong, strain-dependent inhibition of GBS, preserving epithelial cell viability, and impairing pathogen adhesion by up to 98%. Importantly, the multi-strain Lactobacillus combination provided broader and more consistent antagonistic activity, including against MDR, inducible clindamycin-resistant, hypervirulent ST-17-associated, and strongly hemolytic GBS isolates. Although these findings are preliminary, being derived from a limited number of isolates and an in vitro model, they support the promising potential of rationally selected multi-strain Lactobacillus formulations as a strategy to reduce colonization by high-risk GBS lineages and warrant further investigation.
Lung Microbiome Diversity, Infection Dynamics, and Microbe-Mediated Cross-Protection.
Arooj S, Zubair A, Batool SZ … +5 more , Niaz G, Ali M, Waheed Y, Elsharkawy ER, Afghan N
Microbiologyopen · 2026 Jun · PMID 42338083 · Full text
Modern technological advances have revealed that the lungs, once believed to be sterile, actually harbor a diverse community of microorganisms. A normal lung microbiome possesses its own characteristic microbial communit...
Modern technological advances have revealed that the lungs, once believed to be sterile, actually harbor a diverse community of microorganisms. A normal lung microbiome possesses its own characteristic microbial community, although it is largely influenced by the microbiota of the upper respiratory tract. The lung microbiome is distinct from that of other organs due to unique selective pressures, including mechanical clearance through coughing, the activity of pulmonary macrophages, the coordinated movement of respiratory cilia, and the antimicrobial effects of alveolar surfactant. Although recent research has largely concentrated on the pulmonary bacteriome, comparatively little attention has been given to the lung mycobiome and virome. Various databases such as PubMed, Scopus/Web of Science, Google Scholar, and Medline for literature research up to December 2025. This updated review discusses the origin, composition, and functional significance of the lung microbiome, with particular emphasis on its protective role against respiratory pathogens through host-microbe interactions. The review primarily focuses on respiratory disorders such as asthma, along with a range of viral and bacterial infections. Special attention is given to current evidence on how lung microbial communities influence susceptibility to pulmonary infections, as well as how the lung microbiome contributes to host defense during infectious conditions.
Antimicrobial Photodynamic Therapy With New Methylene Blue and Its Combined Effect With Antibiotics Against MDR Acinetobacter baumannii.
Barati B, Navidifar T, Ostovari M … +2 more , Ghanavati R, Darbandi A
Microbiologyopen · 2026 Jun · PMID 42338062 · Full text
The present study aimed to evaluate the antibacterial efficacy of new methylene blue-mediated antimicrobial photodynamic therapy (NMB-mediated aPDT) in combination with tigecycline and colistin against multidrug-resistan...
The present study aimed to evaluate the antibacterial efficacy of new methylene blue-mediated antimicrobial photodynamic therapy (NMB-mediated aPDT) in combination with tigecycline and colistin against multidrug-resistant (MDR) A. baumannii and to explore ROS production as a possible mechanism contributing to the enhanced antibacterial activity of the combined treatments. MIC determination, sublethal irradiation and aPDT assays, checkerboard analysis, and ROS detection were performed. MIC of NMB for this MDR strain was greater than 100 μg/mL. Under various radiation times, aPDT at 12.5 μg/mL NMB was considered a sublethal dose that represented with a reduction of 1.7-2.6 log compared with control, and aPDT at 25 and 50 μg/mL were considered lethal doses that resulting in more reduction of bacterial counts to 3.23-4.3 log CFU/mL and 2.92-4.0 log CFU/mL, respectively. The irradiated NMB at 25 μg/mL and tigecycline at 1/4 × MIC showed a synergistic interaction. In addition, multiple additive interactions were observed at other concentrations of NMB and tigecycline, as well as with colistin at sub-MIC concentrations, and these findings were further confirmed by CFU counting. The increased production of ROS was effectively detected following aPDT alone and in combination of antibiotic with aPDT. These findings suggest that NMB-mediated aPDT alone and in combination with colistin or tigecyclines can be a promising approach to eradicate infections associated with MDR A. baumannii and reduces the development of further antibiotic resistance.
Hypervirulent Klebsiella pneumoniae Infections: A Systematic Review of Clinical, Microbiological, and Outcome Data From Reported Cases.
Sakru N, Cetinkaya E, Aldi FI … +2 more , Inan M, Eryildiz C
Microbiologyopen · 2026 Jun · PMID 42338034 · Full text
Hypervirulent Klebsiella pneumoniae (hvKp) has been increasingly reported in association with invasive infections and multi-organ involvement. This systematic review followed PRISMA guidelines and was registered in PROSP...
Hypervirulent Klebsiella pneumoniae (hvKp) has been increasingly reported in association with invasive infections and multi-organ involvement. This systematic review followed PRISMA guidelines and was registered in PROSPERO (CRD420251060200). PubMed, Scopus, and Web of Science were searched for articles published between 2000 and 2025. We conducted a review of published reports to summarize the clinical, microbiological, and outcome characteristics of reported hvKp infections. Studies reporting individual-level data were included, and descriptive analyses were performed. A total of 778 cases from 376 reports were included. Bloodstream infection and liver involvement were among the most frequently reported clinical features, and multi-organ involvement was commonly described. Virulence factors, including siderophores and capsular types, were frequently reported; however, microbiological findings varied across studies. Among cases with available data, 82.1% had origin from or travel to endemic regions and, 43.1% had diabetes mellitus. This systematic review provides a descriptive overview of reported hvKp infections, highlighting frequently reported clinical and microbiological patterns. However, the findings are based on heterogeneous and predominantly severe cases and should be interpreted with caution. Further studies using standardized definitions and systematically collected data are needed to better characterize hvKp infections.
Synthetic Mirror Bacteria as a Frontier for Chiral Synthetic Biology and Biocontainment.
Bhuiyan MNI
Microbiologyopen · 2026 Jun · PMID 42338029 · Full text
Chirality is a fundamental structural property of biological molecules that governs molecular recognition, enzymatic catalysis, and genetic information processing in living systems. Natural life exhibits a universal patt...
Chirality is a fundamental structural property of biological molecules that governs molecular recognition, enzymatic catalysis, and genetic information processing in living systems. Natural life exhibits a universal pattern of homochirality in which proteins are composed predominantly of l-amino acids, while nucleic acids contain d-sugars within their backbone structures. Advances in synthetic biology and chemical biology have stimulated growing interest in mirror biological systems that operate with inverted molecular chirality. In theory, mirror organisms would contain proteins composed of d-amino acids and nucleic acids built from l-sugars, forming a stereochemically inverted yet internally consistent biochemical framework that is largely incompatible with natural biological systems. This review examined the molecular foundations, engineering strategies, biosafety considerations, and ecological implications associated with the theoretical development of mirror bacteria. Particular emphasis is placed on the hierarchical organization of biological chirality and the stereochemical constraints that govern macromolecular folding, molecular recognition, and the processing of genetic information. Recent advances in the chemical synthesis of mirror proteins and mirror nucleic acids demonstrate that stereochemically inverted biomolecules can adopt stable structures and perform catalytic or informational functions. However, integrating these components into self replicating mirror cellular systems remains a major scientific challenge. Furthermore, the ecological interactions, evolutionary dynamics, and environmental persistence of mirror biological systems require careful biosafety evaluation and responsible governance. This review highlights key conceptual and technological challenges that must be addressed before mirror organisms can progress from theoretical constructs toward experimental feasibility.
Effect of Increased Inoculum Size on Drug Susceptibility of Mycobacterium tuberculosis: Challenges in Reliable Drug Resistance Detection.
Yildirim K, Atas C, Simsek E … +3 more , Moharer MPS, Uzun M, Coban AY
Microbiologyopen · 2026 Jun · PMID 42338009 · Full text
Inoculum preparation of Mycobacterium tuberculosis isolates is a critical step for the reproducibility of drug susceptibility tests (DST) and the prevention of false results. In this study, we investigated the effect of...
Inoculum preparation of Mycobacterium tuberculosis isolates is a critical step for the reproducibility of drug susceptibility tests (DST) and the prevention of false results. In this study, we investigated the effect of increasing inoculum sizes of M. tuberculosis isolates on DST. For this purpose, primary drug susceptibilities of five ATCC strains and 24 M. tuberculosis isolates were determined by the proportion method on 7H10 agar using six different inoculum sizes (10 dilution of McFarland no 1 as reference inoculum and McFarland no 0.5-1-2-3-4). Among the tested isolates (including ATCC strain), 22 of them had DST results at increasing inoculum sizes that were 100% consistent with DST results in the reference inoculum and MGIT-960. For alone streptomycin (STR), in seven isolates tested, DST results at increasing inoculum sizes were 100% consistent with MGIT-960 results but were inconsistent with results determined with the reference inoculum. These isolates were found to be susceptible to STR with reference inoculum, but resistant to STR in MGIT-960 and increasing inoculum sizes. Our study reveals that inoculum size does not affect DST results of M. tuberculosis; on the contrary, increasing the inoculum may have positive results for some antibiotics, such as STR.
Bacteriophages in the Rhizosphere: Roles in Nutrient Cycling, Bacterial Community Structure, and Animal-Mediated Dispersal.
Komijani M, Maddahi H, Rezaei M … +2 more , Abnosi MH, Ahmed AK
Microbiologyopen · 2026 Jun · PMID 42337996 · Full text
The rhizosphere, a critical soil layer around plant roots, is enriched with carbon from root exudates, influencing microbial communities that can either protect against or cause plant diseases. Bacteriophages significant...
The rhizosphere, a critical soil layer around plant roots, is enriched with carbon from root exudates, influencing microbial communities that can either protect against or cause plant diseases. Bacteriophages significantly impact soil nutrient cycles and ecosystem processes through cell lysis and horizontal gene transfer. They play a vital role in the rhizosphere by affecting plant stress responses and climate adaptation. Bacteriophages exert a range of negative effects on Actinobacteria, impacting their ecological and physiological functions by diminishing Actinobacteria's roles in antibiotic production, soil health, and plant growth. Phage predation affects nutrient cycling by influencing nitrogen and carbon metabolism, with evidence showing that phages can alter microbial diversity and function, leading to changes in soil ammonium levels and carbon decomposition rates. In wastewater treatment, bacteriophages can improve process efficiency by targeting harmful bacteria, managing foam formation, and enhancing sludge reduction through enzymatic action. Additionally, bacteriophage dispersal mechanisms in the rhizosphere can be enhanced by rhizosphere-associated animals. Numerous invertebrate and vertebrate animals can significantly alter the rhizosphere environment by amplifying, mobilizing, and distributing both phages and bacterial hosts. Herein, three main mechanisms by which animals enhance the dispersal of bacteriophages in the rhizosphere are discussed. This review discusses bacteriophages' roles in soil ecosystems, highlighting their impact on nutrient cycling, plant health, and soil remediation, as well as animal-mediated phage dispersal mechanisms. Overall, while bacteriophages have potential biotechnological applications, their negative effects on microbial functions and nutrient cycling highlight the need for balanced use and further research.
Clostridioides difficile as a Zoonotic and Foodborne Pathogen: Reviewing the Global Evidence and South African Data.
Gouws M, Strydom PE, Rip D
Microbiologyopen · 2026 Jun · PMID 42337986 · Full text
Clostridioides difficile infections (CDIs) are becoming increasingly problematic in developing countries, further burdening healthcare systems. In Southern Africa, limited information is available on the prevalence and d...
Clostridioides difficile infections (CDIs) are becoming increasingly problematic in developing countries, further burdening healthcare systems. In Southern Africa, limited information is available on the prevalence and diversity of C. difficile strains in animals, food, and the environment. This review aims to provide insight into global findings on strain diversity, antibiotic resistance, and the epidemiology of C. difficile associated with food-producing animals, wildlife, and food processing environments. The review further explores the zoonotic and foodborne risk potential of the pathogen and includes clinical trends of CDIs within South Africa. It is evident that farm environments and animals play a considerable role in the spread of C. difficile. A lack of broad surveillance, incomplete data on CDIs, and the prevalence of C. difficile within South Africa hinder an accurate representation of its zoonotic and foodborne potential.
Detection and Characterization of ESBL-Producing and Carbapenem-Resistant Klebsiella pneumoniae in Ornamental Birds and Their Surrounding Environments.
Hasan MAE, Rana ML, Islam MS … +12 more , Punom SA, Antor MTH, Jany DA, Fahim NAI, Abu Sama Al Faruquee SM, Islam MR, Bakhtiyar Z, Prome AA, Islam MM, Rahman S, Khan MFR, Rahman MT
Microbiologyopen · 2026 Jun · PMID 42337985 · Full text
Extended-spectrum beta-lactamase-producing Klebsiella pneumoniae (ESBL-KP) and carbapenem-resistant Klebsiella pneumoniae (CRKP) represent a global health risk, with ornamental birds serving as potential reservoirs for t...
Extended-spectrum beta-lactamase-producing Klebsiella pneumoniae (ESBL-KP) and carbapenem-resistant Klebsiella pneumoniae (CRKP) represent a global health risk, with ornamental birds serving as potential reservoirs for their dissemination. This study aimed to isolate and characterize ESBL-KP and CRKP from ornamental birds and their surrounding environments. A total of 112 samples, including equal numbers of feces, cage swab, cage water, cage feed, store feed, handler's hand swab, nasal swab, and air samples, were collected equally from both households and pet bird shops. Overall, 52.68% (59/112, CI: 0.435-0.6168) isolates were confirmed as positive, where a higher occurrence was observed in pet store samples (32/56, 57.14%) than in household samples (27/56, 48.21%). In the disk diffusion test, 79.67% (47/59, CI: 0.6773-0.8796) isolates were identified as multidrug-resistant, with high resistance to imipenem and cefotaxime (both 66.10%), meropenem and ceftriaxone (each 59.02%). The occurrence of ESBL-producing isolates was higher in shop samples (26/32, 81.25%) than in household samples (12/27, 44.44%). In the Congo Red assay, 76.28% (45/59, CI: 0.6403-0.8531) isolates were identified as strong biofilm producers. Resistance genes, bla (92.10%), bla (84.21%), bla (78.95%), bla (51.42%), and bla (34.29%), conferring resistance to beta-lactams and carbapenems were detected in the K. pneumoniae isolates, along with virulence genes, uge (100%), entB (83.05%), mrkD (81.36%), and kfu (30.51%). As a first report from Bangladesh, this study highlights the widespread occurrence of ESBL-KP, CRKP and biofilm-producing K. pneumoniae in ornamental birds, emphasizing the urgent need for a One Health approach to prevent associated zoonotic and environmental risks.
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