Phenotypic Characteristics Research Articles

Antibacterial effect of phage cocktails and phage-antibiotic synergy against pathogenic Klebsiella pneumoniae.

The worldwide spread of antimicrobial resistance (AMR) has posed a great challenge to global public health. Phage therapy has become a promising alternative against difficult-to-treat pathogens. One important goal of this study was to optimize the therapeutic efficiency of phage-antibiotic combinations, known as phage-antibiotic synergy (PAS). Through comprehensive analysis of the phenotypic and genotypic characteristics of a large number of CRKp-specific phages, we developed a systematic model for phage cocktail combinations. Crucially, our finding demonstrated that PAS treatments not only enhance the bactericidal effects of colistin and tigecycline against multidrug-resistant (MDR) K. pneumoniae strains in in vitro and in vivo context but also provide a robust response when antibiotics fail. Overall, the optimized PAS therapy demonstrates considerable potential in combating diverse K. pneumoniae pathogens, highlighting its relevance as a strategy to mitigate antibiotic resistance threats effectively.

Detection of KPC-3 producing Escherichia coli ST410 in Volos, Greece.

Escherichia coli A382 was isolated in July 2024 from a positive blood culture obtained from the central venous catheter of a male patient undergoing chemotherapy at the Hospital of Volos, Thessaly, Greece. Whole-genome sequencing analysis revealed that the isolate A382 is E. coli belonging to the ST410 high-risk clone, which co-harbors the blaKPC-3 and blaSHV-182 genes on an IncX3 plasmid. It also harbors blaTEM-1 and has five replicons, as follows: IncX3, IncQ1, CoIRNAI, IncF1A, and IncFIB. Complete genome analysis revealed that E. coli A382 isolate carries a range of virulence factors (iutA, iucC, fimH, fdeC, yehA, yehD, yehC, yehB, cgs, ahha, ccI, hlyE, papC, irp2, fyuA, lpfA, and nlpl) and many other non-beta-lactam resistance determinants, including dfrA14 and sul2, but it is susceptible to aminoglycosides, nitrofurantoin, tigecycline, colistin and ceftazidime-avibactam. In conclusion in this study, we describe the phenotypic and genome characteristics of an extensively drug-resistant E. coli ST410.

Racialized and Geopolitically Charged Contexts of Reception in New Immigrant Destinations

We conceptualize racialized and geopolitical contexts of reception as a comprehensive framework for understanding the incorporation of recent immigrants in new destinations. Racialization is the fluid assignment of racial meanings to physical characteristics, religion, cultural presentation, and language. Geopolitics encompasses national boundaries, border security, regulation of border crossers, and populist–nativist anxieties about identity. We use data derived from a documentary film depicting the 2001 contact between Somali immigrants and a host community in Maine. The reception of these immigrants was profoundly racialized due to their sudden arrival and stark differences in phenotypic, cultural, religious, and linguistic characteristics, all of which were racialized by the host community. The context was geopolitically charged by local memories of the US intervention in Somalia and by the aftermath of 9/11. This study underscores the importance of racialization and geopolitics as intertwined factors that significantly shape immigrant contexts of reception.

Geneticand phenotypic characterization of a novel ST45-K43 carbapenem-resistant Klebsiella pneumoniae strain causing bloodstream infection: a potential clinical threat.

Klebsiella pneumoniae is a common pathogen of nosocomial infection, which can cause pneumonia, urinary tract infection, cystitis, and bloodstream infections (BSIs). Here, we genetically characterize a novel carbapenem-resistant K. pneumoniae (CRKP) strain recovered from the blood of a 44-year-old male patient with severe acute necrotizing pancreatitis and septic shock in China. The strain is a ST45 K. pneumoniae with a novel serotype of K43, named 18SHX166. The susceptibility testing results showed that 18SHX166 was resistant to cephalosporin and carbapenems but still susceptible to ceftazidime-avibactam, quinolones, colistin, and amikacin. Genomic sequencing revealed that 18SHX166 contains three plasmids, namely pSHX166-Hv, pSHX166-KPC, and pSHX166-3. pSHX166-Hv harbored the iucABCD operon, encoding the siderophore of aerobactin. pSHX166-KPC harbored blaKPC-2 gene and possessed complete conjugative regions. The conjugation experiment verified pSHX166-KPC as a self-transmissible plasmid mediating the dissemination of antibiotic resistance, with a conjugation rate of 2.21 × 10-5. Additionally, the growth curve showed that 18SHX166 demonstrates a higher growth rate than the control strains. The characteristics of 18SHX166 indicate a potential high risk of clinical transmission.IMPORTANCEST45-K43 carbapenem-resistant Klebsiella pneumoniae isolate, 18SHX166, carries a carbapenem resistance plasmid and virulence plasmid. It has the characteristics of multidrug resistance, high transmissibility, and a fast growth rate, which could pose a threat to the control of antimicrobial resistance and clinical transmission, causing a severe challenge to public health.

Prevalence and characterization of Burkholderia gladioli in Iran, from bacterial dry rot of saffron corms (Crocus sativus L.)

Iran is the main world producer of saffron (Crocus sativus L.), but a bacterial disease continues to threaten saffron production, causing severe flower failure, rot on flowering tubes, delayed vegetative growth, premature yellowing of leaves, bare patches in saffron farms, reddish-brown lesions in the germination zones of roots, and rot of saffron corms. Field surveys in Razavi-Khorasan and Southern-Khorasan provinces revealed high incidence of Burkholderia gladioli dry rot symptoms in saffron farms, with symptoms observed during flowering on leaves and corms. Twenty-four bacterial isolates from symptomatic saffron corms from different parts of Iran were characterized. These bacteria were identified as Burkholderia gladioli, based using phenotypic characteristics, species-specific PCR, and sequencing analyses of the 16S rRNA and 16S-23S intergenic transcribed spacer regions. All 24 isolates triggered hypersensitive reactions in tobacco and pelargonium leaves, although pathogenicity tests showed that only 21 isolates were capable of causing rots on saffron corms.

Characterization of Bacillus pacificus KUMBNGBT-39-Derived Polyhydroxybutyrate and Impact of Physicochemical Factors on its Production.

The extensive use of various chemicals in synthetic plastics is toxic and threatens the biosphere. To address this, the study aimed to isolate, screen, characterize, optimize, and quantify polyhydroxybutyrate (PHB)-producing bacteria using cost-effective residues. Isolated from a landfill site, the Gram-positive, rod-shaped, spore-forming, motile bacterium with intracellular PHB granules was identified as Bacillus pacificus based on phenotypic and genotypic characteristics. Optimal PHB production parameters included a nutrient broth medium, 72h of incubation, a temperature of 37° C, a pH of 7.0, glucose as the carbon source, ammonium chloride as the nitrogen source, and a carbon-to-nitrogen ratio of 4:1, resulting in a 1.42-fold PHB production increase. B. pacificus was also cultured on various low-cost substrates. Among the oil wastes, feedstock showed the highest PHB production (1.983 ± 0.005g/L) and among agricultural residues, the maximum PHB was obtained from rice bran (1.626 ± 0.01g/L). UV-visible spectrophotometric, FT-IR, and HR-LCMS analysis of extracted PHB confirmed characteristics of PHB molecules (ʎ-max at 210nm, functional groups between 1152 and 2925cm-1). The 1H NMR analysis revealed distinct signals for protons resonating at aliphatic CH3 proton groups, bridged CH protons, and shielding CH2 proton regions that matched PHBs. Thermal gravimetric analysis (TGA) and direct scanning colorimetric (DSC) analysis revealed 89.4% degradation and melting temperature at 124.1°C for the extracted PHB compound.

Skull bone marrow-derived immune cells infiltrate the injured cerebral cortex and exhibit anti-inflammatory properties

Identifying the origins and contributions of peripheral-derived immune cell populations following brain injury is crucial for understanding their roles in neuroinflammation and tissue repair. This study investigated the infiltration and phenotypic characteristics of skull bone marrow-derived immune cells in the murine brain after traumatic brain injury (TBI). We performed calvarium transplantation from GFP donor mice and subjected the recipients to controlled cortical impact (CCI) injury 14 days post-transplant. Confocal imaging at 3 days post-CCI revealed GFP+ calvarium-derived cells were present in the ipsilateral injured cortex, expressing CD45 and CD11b immune markers. These cells included Ly6G-positive neutrophil or Ccr2-positive monocyte identities. Calvarium-derived GFP+/Iba1+ monocyte/macrophages expressed the efferocytosis receptor MERTK and displayed engulfment of NeuN+ and cleaved caspase 3+ apoptotic cells. Phenotypic analysis showed that greater calvarium-derived monocytes/macrophages disproportionately express the anti-inflammatory arginase-1 marker than pro-inflammatory CD86. To differentiate the responses of blood- and calvarium-derived macrophages, we transplanted GFP calvarium skull bone into tdTomato bone marrow chimeric mice, then performed CCI injury 14 days post-transplant. Calvarium-derived GFP+cells predominantly infiltrated the lesion boundary, while blood-derived tdTomato+ cells dispersed throughout the lesion and peri-lesion. Compared to calvarium-derived cells, more blood-derived cells expressed pro-inflammatory CD86 and displayed altered 3D morphologic traits. These findings uniquely demonstrate that skull bone marrow-derived immune cells infiltrate the brain after injury and contribute to the neuroinflammatory milieu, representing a novel immune cell source that may be further investigated for their causal role in functional outcomes.

Characterization, registration and gazette notification

The first animal to be domesticated by the man was dog which probably occurred at least 14,000 years ago- the animals being used for hunting and as watchdogs. In India many exotic dog breeds (mainly German Shepherd, Labrador, Doberman, Pomeranian etc) are kept as pet but little emphasis has been given to the native dog breeds. Some Indian breeds of dogs reported in India are Caravan Hound, Combai, Chippiparai, Rajapalayam, Rampur Hound, Kanni, Mudhol Hound, Indian Mastiff (Bulli), Himalayan sheep dog, Bhutia dogs, Bhakarwal dogs etc. ICAR-NBAGR has developed methodology for characterization of dog breeds of Indian through systematic survey in the area of its distribution along with Breed Descriptors format for dog breeds. Phenotypic characterization of two indigenous dog breeds viz Rajapalayam and Chippiparai were completed by ICAR-NBAGR. Rajapalayam and Chippiparai dogs are exclusively reared for guarding the farm and farm houses. Chippiparai dogs are even given to brides during marriage. There is huge demand for the pups of these dog breeds. State of Karnataka has also completed the characterization of Mudhol hound breed. All three dog have been registered by ICAR & Gazette notified by Govt. of India.

Phenotypic characterization of the native yaks of Sikkim

Native yaks of Sikkim are reared in a pastoral production system by the tribal Dokpa community for their economic and socio-religious significance. Sikkimese yaks are phenotypically distinguishable from the yaks found in the neighbouring state of Arunachal Pradesh. Animals are generally black, broad and convex forehead, horizontal ears, curved upward pointing horns and docile temperament. Females have round udder and cylindrical teats. Also, Sikkimese yaks have comparatively shorter body length, lesser heart girth and greater height at withers as compared to Arunachali yaks. Animals are reared in a pastoral production system with characteristic features like seasonal migration, temporary shelters, highland forage grazing and ethno-veterinary practices. However, there are certain threats, which must be countered to ensure the continual existence and sustainability of this valuable germplasm.

Ferric uptake regulator (Fur) in Vibrio mimicus acts as an activator of citrate cycle and oxidative phosphorylation pathways, while enhancing virulence potential

Ferric uptake regulator (Fur) is a crucial bacterial regulator that controls the uptake of iron by bacteria, hence influencing their survival and pathogenicity. Vibrio mimicus is an epidemic pathogen that is harmful to aquatic animals and human health, with the characteristics of rapid onset and high mortality after infecting the fish. At present, the function and mechanism of Fur in V. mimicus are still unclear. In this study, the fur gene deletion strain and complementation strain of V. mimicus were constructed. Following fur deletion, proteomic analysis revealed that the abundance of 258 proteins was considerably up-regulated while the abundance of 307 proteins was dramatically down-regulated. The primary roles of these differentially expressed proteins were in a variety of pathways, including virulence, metabolism, enzymes, and so on. Among them, citrate cycle and oxidative phosphorylation were the main pathways affected by Fur. The activities of key enzymes in these two pathways were assessed. The results indicated a decrease in the activities of respiratory chain complexes II and IV, succinate dehydrogenase (SDH), and α-ketoglutarate dehydrogenase (α-KGDH) in the Δfur strain. Conversely, the activity of isocitrate dehydrogenase (NAD-IDH) was increased. Phenotypic characterization showed that the Δfur strain exhibited delayed growth, reduced motility, defective biofilm formation, decreased resistance to oxidative stress, increased adhesion, and decreased virulence. Besides, the LD50 of the Δfur strain was 31-fold higher than that of the WT strain. These results indicate that Fur serves as an activator for the citrate cycle and oxidative phosphorylation pathway in V. mimicus, and contributing to its virulence. Our findings enhance the understanding of the biological functions of Fur and lay the groundwork for further investigation into the regulatory mechanisms of Fur in V. mimicus.

Genetic approach to discover a valuable gene for enhanced nutritional value in the edible filamentous fungus Fusarium venenatum

AbstractMycoprotein is critical in a dietary shift toward a more sustainable food system. However, the strain improvement for enhancing mycoprotein via genetic manipulation is lacking. Here, we investigated the functions of proteins related to ubiquitin and small ubiquitin‐like modifier (SUMO) modifications using a gene‐knockout strategy in Fusarium venenatum, a mycoprotein fungus closely related to the fungal genetics model species Fusarium graminearum. Among the candidate genes, we specifically focused on the putative SUMO‐associated gene UBQ14 based on phenotypic characteristics in F. graminearum. In the FvUBQ14 knockout mutant in F. venenatum, nutritional profiles showed prominent differences in amino acid and fatty acid composition compared to the wild‐type strain. Furthermore, through proteomic analysis, we confirmed that the loss of FvUBQ14 leads to metabolic changes, particular in amino acid biosynthesis and degradation, resulting in an increase in amino acid composition in F. venenatum. Our findings provide new insights into filamentous fungal food improvement through genetic engineering and contribute to advances in alternative protein industry.

Impact of Extreme Prematurity, Chorioamnionitis, and Sepsis on Neonatal Monocyte Characteristics and Functions

Introduction: The innate branch of the immune system is important in early life, in particular for infants born preterm. Methods: We performed a longitudinal analysis of the peripheral monocyte compartment in extremely preterm children from a randomized, placebo-controlled study of probiotic supplementation. PBMCs and fecal samples were collected at several timepoints during the first months of life. Monocyte characteristics were analyzed by flow cytometry, and LPS-stimulated PBMC culture supernatants were analyzed by Luminex or ELISA. Plasma cytokines and gut microbiota composition were analyzed by ELISA and 16S rRNA-sequencing, respectively. Results: The extremely preterm infants had persistent alterations in their monocyte characteristics that were further aggravated in chorioamnionitis cases. They showed a markedly reduced TLR4 expression and hampered LPS-stimulated cytokine responses 14 days after birth. Notably, at later timepoints, TLR4 expression and LPS responses no longer correlated. Sepsis during the first weeks of life strongly associated with increased pro-inflammatory, and reduced IL-10, responses also at postmenstrual week 36. Further, we report a correlation between gut microbiota features and monocyte phenotype and responses, but also that probiotic supplementation associated with distinct monocyte phenotypic characteristics, without significantly influencing their responsiveness. Conclusion: Extremely preterm infants have monocyte characteristics and functional features that deviate from infants born full-term. Some of these differences persist until they reach an age corresponding to full-term, potentially making them more vulnerable to microbial exposures during the first months of life.

The molecular regulatory mechanism of reed canary grass under salt, waterlogging, and combined stress was analyzed by transcriptomic analysis

BackgroundReed canary grass has been identified as a suitable species for restoring plateau wetlands and understanding plant adaptation mechanisms in wetland environments. In this study, we subjected a reed canary grass cultivar ‘Chuanxi’ to waterlogging, salt, and combined stresses to investigate its phenotypic characteristics, physiological indices, and transcriptome changes under these conditions.ResultsThe results revealed that the growth rate was slower under salt stress than under waterlogging stress. The chlorophyll content and energy capture efficiency of the PS II reaction center decreased with prolonged exposure to each stress. Conversely, while the activities of enzymes associated with respiratory metabolism, as well as MDA, PRO, Na+, and K+-ATPase, increased. The formation of distinct aerenchyma was observed under waterlogging stress and combined stress. Transcriptome sequencing analysis identified 5,379, 4,169, and 14,993 DEGs under CK vs. W, CK vs. S, and CK vs. SW conditions, respectively. The WRKY was found to be the most abundant under waterlogging stress, whereas the MYB predominated under salt stress and combined stress. Glutathione metabolic pathways and Plant hormone signal transduction have also been found to play important roles in stress.ConclusionBy integrating phenotypic, physiological, anatomical, and transcriptomic, this research provides valuable insights into how reed canary grass responds to salt, waterlogging, and combined stresses. These findings may inform the ecological application of reed canary grass in high-altitude wetlands and for breeding purposes.

Yunchengibacter salinarum gen. nov., sp. nov., a novel bacterium of the family Kordiimonadaceae isolated from sediment in Yuncheng salt lake.

A Gram-stain-negative, aerobic, motile and rod-shaped bacterium, the color of the bacterial colony ranges from light yellow to yellow, designated YC-2023-2T, was isolated from sediment sample of Yuncheng salt lake. Growth occurred at 15-45℃ (optimum 37℃), pH 6.0-9.0 (optimum pH 7.0-8.0) and with 0-8.0% NaCl (w/v, optimum 2.0%). The phylogenetic analysis based on 16S rRNA gene sequences showed that strain YC-2023-2T belonged to the family Kordiimonadaceae. The closely related members were Gimibacter soli 6D33T (92.38%), Kordiimonas lipolytica M41T (91.88%), Eilatimonas milleporae DSM 25217T (91.88%) and Kordiimonas gwangyangensis JCM 12864T (91.84%). The genome of strain YC-2023-2T was 2957513 bp, and the genomic DNA G+C content was 63.91%. The main respiratory quinone was Q-10 and the major fatty acids (>10%) were iso-C15:0, C16:0, C19:0 cyclo ω8c, Summed Feature 8 (C18:1 ω6c or C18:1 ω7c) and Summed Feature 9 (iso-C17:1 ω9c or C16:0 10-methyl). The major polar lipids consisted of phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylglycerol, unidentified glycolipid, unidentified lipid, and two unidentified aminolipids. Based on the phylogenetic, phenotypic and chemotaxonomic characteristics, strain YC-2023-2T is proposed to represent a novel species of a novel genus named Yunchengibacter salinarum gen. nov., sp. nov., within the family Kordiimonadaceae. The type strain is YC-2023-2T (= GDMCC 1.4502T = KCTC 8546T).

A simple culture medium for phenotypic characterization and long-term storage of medically relevant fusarioid fungi

Fusarioid fungi, particularly Neocosmospora solani and Fusarium oxysporum, are emerging as significant human pathogens, causing infections ranging from localized mycoses to life-threatening systemic diseases. Accurate identification and preservation of these fungi in clinical laboratories remain challenging because of their diverse morphologies and specific growth requirements. This study evaluated a novel milk-honey and malt agar (MHM) against conventional media for cultivating and preserving 60 clinical fusarioid isolates, including Neocosmospora spp. (n = 47), Bisifusarium spp. (n = 5), and Fusarium spp. (n = 8). Compared with Sabouraud dextrose 2 % agar (SDA) and malt extract agar (ME2), MHM significantly increased conidia production (p < 0.0001, mean = 3.4 × 103, standard deviation (SD) = ±1.3 × 103), with results similar to those of carnation leaf agar (CLA). MHM facilitated superior preservation of fusarioid viability for up to one year at room temperature on slant cultures and over two years on swabs in Amies gel with charcoal, outperforming current methods such as Castellani (water) or cryopreservation. Morphological characterization of fusarioid fungi grown on MHM revealed distinct growth patterns and conidial structures for Neocosmospora, Bisifusarium, and Fusarium species, aiding in identifying these genera. The superior performance of MHM in stimulating conidiation, maintaining viability, and preserving morphology underscore its potential as a reference medium for medically relevant fusarioid fungi, with broad implications for clinical mycology laboratories and resource-limited settings.

Deep Immunoprofiling of Large-Scale Tuberculosis Dataset at Single Cell Resolution Reveals a CD81bright γδ T Cell Population Associated with Latency.

Tuberculosis (TB) remains one of the leading causes of death among infectious diseases, with 10.6 million new cases and 1.3 million deaths reported in 2022, according to the most recent WHO report. Early studies have shown an expansion of γδ T cells following TB infection in both experimental models and humans, indicating their abundance among lung lymphocytes and suggesting a role in protective immune responses against Mycobacterium tuberculosis (M. tuberculosis) infection. In this study, we hypothesized that distinct subsets of γδ T cells are associated with either protection against or disease progression in TB. To explore this, we applied large-scale scRNA-seq and bulk RNA-seq data integration to define the phenotypic and molecular characteristics of peripheral blood γδ T cells. Our analysis identified five unique γδ T subclusters, each with distinct functional profiles. Notably, we identified a unique cluster significantly enriched in the TCR signaling pathway, with high CD81 expression as a conserved marker. This distinct molecular signature suggests a specialized role for this cluster in immune signaling and regulation of immune response against M. tuberculosis. Flow cytometry confirmed our in silico results, showing that the mean fluorescence intensity (MFI) values of CD81 expression on γδ T cells were significantly increased in individuals with latent TB infection (TBI) compared to those with active TB (ATB). This finding underscores the importance of CD81 and its associated signaling mechanisms in modulating the activity and function of γδ T cells under TBI conditions, providing insights into potential therapeutic targets for TB management.

Phenotypic and genetic characterization of children with Wilson Disease from Northeast China

BackgroundWilson disease (WD) is an autosomal recessive inherited disease caused by ATP7B variants and characterized by copper metabolism defects. However, children with WD are often asymptomatic, making the clinical diagnosis difficult. Therefore, more accurate methods are required for clinical diagnosis. The objective of this study was to highlight the phenotypic and genetic characteristics of children with WD in northeast China.MethodsWe retrospectively analyzed the clinical data and gene sequencing results of 65 children with WD from January 1, 2014, to December 31, 2022, at the Shengjing Hospital of China Medical University. All data refer to the time of diagnosis before treatment.ResultsThe median age at diagnosis was 5 years (range 1.2–15 years). In 50 cases (50/65, 76.9%) patients, routine physical examinations revealed only abnormal liver function. However, they had a significantly negative (p < 0.05) Kayser–Fleischer ring (KF). Children with acute liver failure had significantly increased 24 h urinary copper excretion (p < 0.05). We detected 46 genetic variants of ATP7B, including seven novel variants. The most frequent variant was p.R778L with an allele frequency of 38.7%. Phenotype-genotype correlation analysis suggested that p.R778L was significantly associated with lower serum ceruloplasmin levels and higher zinc levels (p < 0.05). The loss-of-function (LOF) variant was associated with significantly lower albumin levels (p < 0.05).ConclusionMost children with WD are asymptomatic, which makes early diagnosis of WD difficult. Therefore, clinical and laboratory characteristics as well as genetic testing are essential. p.R778L is the most frequent variant of ATP7B in China and may play an important role in lowering serum ceruloplasmin levels.

Clinical, phenotypic characterization and genomic analysis of the mucoid Acinetobacter baumannii from a teaching hospital

BackgroundAcinetobacter baumannii (A. baumannii) has become a significant nosocomial pathogen globally over the past decade due to the increasing prevalence of antibiotic-resistant isolates. The formation of the mucoid phenotype is a crucial adaptive defense response to external pressure, but the clinical, phenotypic and genotypic characteristics and their relationship with sequence types (ST) and K locus (KL) types remain unclear. MethodsIn this study, we screened a total of 736 A. baumannii isolates, from which we identified and characterized 13 mucoid isolates. The study explored the clinical characteristics of patients with mucoid isolates, investigated the mucoid phenotype, performed capsule observation, quantified capsule production, and assessed antimicrobial susceptibility. Subsequently, whole-genome sequencing (WGS) was used to analyze the sequence types (ST), loci for capsular polysaccharide (KL), antibiotic resistance genes, virulence genes, and core-genome single-nucleotide polymorphisms (SNPs). Additionally, the virulence of all mucoid strains was evaluated through serum resistance assay, biofilm-forming assay, and Galleria mellonella survival assay. ResultsAll mucoid A. baumannii isolates were found to be encapsulated and extremely drug-resistant. Among patients infected with these isolates, 92.3 % had pulmonary infections, and the 30-day mortality rate was 61.5 %. The analysis revealed that not all strains are highly virulent. Whole-genome sequencing (WGS) identified the sequence types as ST136, ST208, ST381, ST195, and ST281, and the capsular types as KL77, KL7, KL33, KL2, and KL3. The ST208 and KL7 isolates exhibited higher virulence and greater biofilm formation, with KL7 isolates also showing higher capsule production. Despite these differences, no significant variations in virulence genes were observed among the mucoid isolates, except for biofilm-associated and quorum-sensing genes. The highly virulent ST208/KL7 strains (AB276, AB313, and AB552) lacked biofilm-associated genes (csuA/BABCDE), indicating these genes do not directly cause differences in biofilm formation. ConclusionThe mucoid A. baumannii isolates were extensively drug-resistant, and infections caused by these isolates could lead to higher mortality. However, not all strains had high virulence, with variations likely related to specific sequence types (ST) and K locus (KL) types.

Characterization of the Retinal Phenotype Using Multimodal Imaging in Novel Compound Heterozygote Variants of CYP2U1

Characterization of the Retinal Phenotype Using Multimodal Imaging in Novel Compound Heterozygote Variants of CYP2U1

Multilocus sequence typing and phenotypic properties of Streptococcus mutans from Thai children with different caries statuses

BackgroundStreptococcus mutans is studied for its acidogenic and aciduric characteristics, notably its biofilm formation in the presence of sucrose, toward its role in the caries process. Variations in both genotype and phenotype have been reported among clinical isolates of S. mutans. This study aimed to examine genotypic and phenotypic characteristics of S. mutans obtained from Thai children with varying caries statuses.MethodsWe determined the presence of S. mutans and caries status in 395 children aged 3–4 years. From 325 children carrying S. mutans, we selected 90 with different caries statuses—caries-free (CF; n = 30), low severity of caries (LC; n = 30), or high severity of caries (HC; n = 30). Three isolates of S. mutans were taken from each child, thus, a total of 270 isolates were obtained. Multilocus sequence typing (MLST) was used to genotype the isolates and assess their clonal relationships. The properties, including biofilm formation, collagen binding, and acid production and tolerance were also evaluated.ResultsChildren with carious lesions showed a higher detection rate and number of S. mutans in saliva than those without caries. S. mutans from individuals with HC status showed the lowest biofilm formation ability, while this group had the highest detection rate of collagen-binding isolates. There was no difference in acid production or tolerance by caries status. Genotyping by MLST did not reveal any clone of S. mutans specific to CF status. This result remained even when we included MLST data from the open-access PubMLST database. MLST did identify clones containing only strains from caries-affected hosts, but tests of their phenotypic properties did not reveal any differences between S. mutans from these clones and clones that were from both caries-free and caries-affected children.ConclusionsThe clonal relationships of S. mutans indicated by MLST were not associated with the status of dental caries in the host.