Kocuria Species Infections in Humans-A Narrative Review

Novel green synthesis of silver nanoparticles using carotenoid extracted from Kocuria sp.: determination of antioxidant, antimicrobial, and anti-human breast cancer activities

In recent decades, nanotechnology has emerged as a promising field with diverse medical applications. Silver nanoparticles (Ag NPs) exhibit several biological activities. The aim of the current study was to investigate antioxidant, antimicrobial, and anti-breast cancer properties of green-synthesized Ag NPs. To achieve this, Ag NPs were synthesized using Kocuria sp., and their successful formation and physicochemical properties were evaluated using UV-vis, FTIR, XRD, DLS, zeta potential analysis, SEM, and TEM. The antioxidant capacity of Ag NPs was evaluated using a DPPH scavenging assay. The antimicrobial effects of the Ag NPs were tested on two Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa) and two Gram-positive bacteria (Bacillus subtilis and Staphylococcus aureus) using a 96-well plate. HUVEC, MCF7, and MDA-MB-231 cells were treated with varying concentrations of Ag NPs, and cell viability, migration, and apoptosis rates were assessed using MTT, scratch, and flow cytometry assays, respectively. Additionally, qPCR was performed to analyze the expression levels of some genes involved in apoptosis, such as caspases 3, 8, and 9. Characterization techniques confirmed the successful synthesis of pure crystalline structures and spherical Ag NPs. Antioxidant and antimicrobial assays demonstrated the significant antioxidant capacity of the Ag NPs and their antibacterial properties against all tested bacteria. Moreover, in vitro studies indicated that Ag NPs effectively inhibited cell proliferation, suppressed migration, and induced apoptosis, likely owing to the upregulation of caspase 3, 8, and 9 and BCL2 downregulation genes. Our findings suggest that green-synthesized Ag NPs using carotenoids extracted from Kocuria sp. might serve as promising antibacterial and anti-breast cancer agents; however, more in vitro and in vivo investigations are required to elucidate the therapeutic potential of Ag NPs.

Exploring Peri-Implantitis Risk-Factors: A Cross-Sectional Study

Background/Objectives: With the increasing use of dental implants in edentulous patients and the high prevalence of peri-implantitis, understanding its microbial and risk factors is crucial. This study investigated Romanian patients from two private dental clinics in Cluj-Napoca, Romania, diagnosed with peri-implantitis, focusing on identifying the predominant bacterial species at affected sites compared with healthy implant sites. Additionally, we examined the impact of factors such as smoking, gender, age, and prosthetic restoration type on disease prevalence. Methods: This cross-sectional study, conducted between January 2023 and December 2024, included randomly selected patients who met the predefined inclusion and exclusion criteria. We enrolled 22 patients and 50 implants in the study. Data collected from medical records, clinical evaluations, and microbiological assessments were subsequently entered into a computerized database. Clinical data were analyzed using Social Science Statistics software(Jeremy Staangroom 2018). Bacterial samples were assessed, incubated, and subsequently identified using the Vitek 2 Compact System (BioMérieux, Marcy-l' Étoile, France). Results: Peri-implantitis incidence was found to be independent of gender, more prevalent in the mandible, and equally affected smokers and non-smokers. The disease involves a complex polymicrobial infection, with pathogenic bacteria triggering the condition and opportunistic bacteria sustaining it. Conclusions: Peri-implantitis is a complex polymicrobial infection that arises from the interaction of strict pathogenic bacteria and opportunistic bacteria. Peri-implantitis results from intricate interactions of local, systemic, and microbial factors. Identifying its causes is essential for developing effective treatments, with future research emphasizing the role of opportunistic bacteria in disease progression.

A Rare Agent in Blood: Rothia kristinae

Rothia kristinae, a Gram-positive coccus often regarded as a harmless commensal, is emerging as a potential pathogen, especially in immunocompromised patients. We hereby present a case involving R. kristinae bacteremia in a 66-year-old female patient with a history of multiple myeloma and end-stage renal disease following a hematopoietic stem cell transplant. Despite initial doubts about its clinical significance, repeated isolation from blood cultures prompted consideration of infection rather than colonization. This case highlights the importance of considering rare pathogens in immunocompromised hosts. Additional investigation is essential to gain a more comprehensive understanding of the clinical features and management of infections caused by R. kristinae.

Impact of Storage Conditions on the Quality of Raw Camel Milk

The preservation and transportation of raw camel milk are essential for the maintenance of its molecular biological activity. Prolonged storage periods and improper storage temperatures can diminish both the nutritional value and biological functionality of its constituent molecules. This study examines the effects of storage conditions on commercially sourced Bactrian camel milk from Delingha City, Qinghai Province, China. Results indicate that the levels of protein, amino acids, fats, and fatty acids in camel milk stored in a 4°C milk tanker truck decrease progressively over a period of 0 to 7 days. Microbial analysis indicates a shift in microbial composition over time, characterized by a notable rise in Psychrobacter and a marked decline in Kocuria. These alterations in microbial populations result in the degradation of various components. Drawing on previous research, this study underscores the unsuitability of transporting camel milk over long distances in 4°C milk tankers to preserve the quality and nutritional integrity of the product.

Valorisation of tomato pomace in anti-pollution and microbiome-balance face cream

Tomato pomace, the main by-product of tomato processing, is also an underestimated source of many active substances. This study aimed to determine the possibility of using oil obtained from tomato pomace in a face cream formulation. The bacterial community structure, face skin biophysical parameters and protection against air pollution were examined after daily application of the cosmetic by volunteers. In the tomato pomace oil, the profile of fatty acids was determined by GC‒MS, and the profile of volatile compounds was determined using the HS-SPME technique. The dominant bioactive component in the oil was linoleic acid (63.6%), and among the volatile compounds, it was carvotanacetone (25.8%). The application of the cream with tomato pomace oil resulted in an increase in the dominant genera Staphylococcus, Anaerococcus and Cutibacterium in the epibiome, particularly beneficial Staphylococcus epidermidis, while limiting the growth of the potentially opportunistic pathogens Kocuria spp., Micrococcus spp., Veillonella spp., and Rothia spp. This study showed the usefulness of tomato pomace oil as a natural ingredient in skin care cosmetics, reducing skin inflammation, sensitivity and melanin level, with potential protective effects against air pollution and microbiome-balance properties. Tomato pomace, which is commonly considered waste after tomato processing, can be used in the development of new cosmetics and may additionally contribute to reducing environmental nuisance.

Kocuria rosea Sepsis in an Immunocompromised Patient: A Case Report

Kocuria species, classified within the phylum Actinomycetota, class Actinomycetes, order Micrococcales, family Micrococcaceae, are Gram-positive coccoid bacteria. They bear morphological resemblance to Staphylococci spp and Micrococci spp, which often leads to misidentification and oversight as contaminants, given their presence as normal flora on human and animal skin and mucous membranes. Accurate identification of these organisms typically relies on automated systems such as MALDI-TOF-MS, Vitek-2 System, and 16S rRNA studies. Once considered rare, there is increasing recognition of Kocuria spp due to its emerging involvement in human infections. With increasing reports of infections associated with these bacteria, it is essential for clinical microbiologists to analyze and document the properties of the organism. This will aid clinicians in enhancing patient care and management. We present the case of a 53-year-old male patient with a complex medical history, including end-stage renal disease on maintenance hemodialysis, anemia of chronic disease, type 2 diabetes mellitus, and a history of rheumatic heart disease status post mitral valve replacement. This patient developed Kocuria rosea sepsis secondary to a central line catheter infection, highlighting the emerging clinical significance of Kocuria species in immunocompromised individuals.

Causal effects of skin microbiota on intervertebral disk degeneration, low back pain and sciatica: a two-sample Mendelian randomization study

OBJECTIVE

The purpose of this study is to use two-sample Mendelian randomization (MR) to investigate the causal relationship between skin microbiota, especially Propionibacterium acnes, and intervertebral disc degeneration (IVDD), low back pain (LBP) and sciatica.

METHODS

We conducted a two-sample MR using the aggregated data from the whole genome-wide association studies (GWAS). 150 skin microbiota were derived from the GWAS catalog and IVDD, LBP and sciatica were obtained from the IEU Open GWAS project. Inverse-variance weighted (IVW) was the primary research method, with MR-Egger and Weighted median as supplementary methods. Perform sensitivity analysis and reverse MR analysis on all MR results and use multivariate MR to adjust for confounding factors.

RESULTS

MR revealed five skin microbiota associated with IVDD, four associated with LBP, and two with sciatica. Specifically, P.acnes in sebaceous skin environments were associated with reduced risk of IVDD; IVDD was found to increase the abundance of P.acnes in moist skin. Furthermore, ASV010 [Staphylococcus (unc.)] from dry skin was a risk factor for LBP and sciatica; ASV045 [Acinetobacter (unc.)] from dry skin and Genus Rothia from dry skin exhibited potential protective effects against LBP; ASV065 [Finegoldia (unc.)] from dry skin was a protective factor for IVDD and LBP. ASV054 [Enhydrobacter (unc.)] from moist skin, Genus Bacteroides from dry skin and Genus Kocuria from dry skin were identified as being associated with an increased risk of IVDD. Genus Streptococcus from moist skin was considered to be associated with an increased risk of sciatica.

CONCLUSIONS

This study identified a potential causal relationship between skin microbiota and IVDD, LBP, and sciatica. No evidence suggests skin-derived P.acnes is a risk factor for IVDD, LBP and sciatica. At the same time, IVDD can potentially cause an increase in P.acnes abundance, which supports the contamination theory.

Interspecies interactions in dairy biofilms drive community structure and response against cleaning and disinfection

Interspecies interactions within a biofilm community influence population dynamics and community structure, which in turn may affect the bacterial stress response to antimicrobials. This study was conducted to assess the impact of interactions between Kocuria salsicia and a three-species biofilm community (comprising Stenotrophomonas rhizophila, Bacillus licheniformis, and Microbacterium lacticum) on biofilm mass, the abundance of individual species, and their survival under a laboratory-scale cleaning and disinfection (C&D) regime. The presence of K. salsicia enhanced the cell numbers of all three species in pairwise interactions. The outcomes derived from summing up pairwise interactions did not accurately predict the bacterial population dynamics within communities of more than two species. In four-species biofilms, we observed the dominance of S. rhizophila and B. licheniformis, alongside a concurrent reduction in the cell counts of K. salsicia and M. lacticum. This pattern suggests that the underlying interactions are not purely non-transitive; instead, a more complex interplay results in the dominance of specific species. We observed that bacterial spatial organization and matrix production in different mixed-species combinations affected survival in response to C&D. Confocal microscopy analysis of spatial organization showed that S. rhizophila localized on the biofilm formed by B. licheniformis and M. lacticum, and S. rhizophila was more susceptible to C&D. Matrix production in B. licheniformis, evidenced by alterations in biofilm mass and by scanning electron microscopy, demonstrated its protective role against C&D, not only for this species itself, but also for neighbouring species. Our findings emphasise that various social interactions within a biofilm community not only affect bacterial population dynamics but also influence the biofilm community's response to C&D stress.

Dietary intakes of vitamin D promote growth performance and disease resistance in juvenile grass carp (Ctenopharyngodon idella)

Vitamin D3 (VD3) is an essential nutrient for fish and participates in a variety of physiological activities. Notably, both insufficient and excessive supplementation of VD3 severely impede fish growth, and the requirements of VD3 for fish vary considerably in different species and growth periods. The present study aimed to evaluate the appropriate requirements of VD3 for juvenile grass carp (Ctenopharyngodon idella) according to growth performance and disease prevention capacity. In this study, diets containing six supplemental levels of VD3 (0, 300, 600, 1200, 2400, and 4800 IU/kg diet) were formulated to investigate the effect(s) of VD3 on the growth performance, antioxidant enzyme activities, and antimicrobial ability in juvenile grass carp. Compared with the VD3 deficiency group (0 IU/kg), the supplementation of 300-2400 IU/kg VD3 significantly enhanced growth performance and increased antioxidant enzyme activities in the fish liver. Moreover, dietary supplementation of VD3 significantly improved the intestinal health by manipulating the composition of intestinal microbiota in juvenile grass carp. In agreement with this notion, the mortality of juvenile grass carp fed with dietary VD3 was much lower than that in VD3 deficient group upon infection with Aeromonas hydrophila. Meanwhile, dietary supplementation of 300-2400 IU/kg VD3 reduced bacterial load in the spleen and head kidney of the infected fish, and 1200 IU/kg VD3 supplementation could decrease enteritis morbidity and increase lysozyme activities in the intestine. These findings strengthened the essential role of dietary VD3 in managing fish growth and antimicrobial capacity. Additionally, based on weight gain ratio and lysozyme activities, the appropriate VD3 requirements for juvenile grass carp were estimated to be 1994.80 and 2321.80 IU/kg diet, respectively.

The Impact of Environmental Gaseous Pollutants on the Cultivable Bacterial and Fungal Communities of the Aerobiome

Understanding air microbial content, especially in highly polluted urban areas, is crucial for assessing its effect on human health and ecosystems. In this context, the impact of gaseous pollutants on the aerobiome remains inconclusive due to a lack of studies separating this factor from other contaminants or environmental factors. In this study, we aimed to experimentally assess the influence of contrasting concentrations of atmospheric gaseous pollutants as isolated variables on the composition of the aerobiome. Our study sites were contrasting Air Quality Index (AQI) sites of the Metropolitan Region of Chile, where nitric oxide (NO) was significantly lower at the low-AQI site than at the high-AQI site, while ozone (O3) was significantly higher. Cultivable aerobiome communities from the low-AQI site were exposed to their own pollutants or those from the high-AQI site and characterized using high-throughput sequencing (HTS), which allowed comparisons between the entire cultivable communities. The results showed increased alpha diversity in bacterial and fungal communities exposed to the high-AQI site compared to the low-AQI site. Beta diversity and compositional hierarchical clustering analyses revealed a clear separation based on NO and O3 concentrations. At the phylum level, four bacterial and three fungal phyla were identified, revealing an over-representation of Actinobacteriota and Basidiomycota in the samples transferred to the high-AQI site, while Proteobacteria were more abundant in the community maintained at the low-AQI site. At the functional level, bacterial imputed functions were over-represented only in samples maintained at the low-AQI site, while fungal functions were affected in both conditions. Overall, our results highlight the impact of NO and/or O3 on both taxonomic and functional compositions of the cultivable aerobiome. This study provides, for the first time, insights into the influence of contrasting pollutant gases on entire bacterial and fungal cultivable communities through a controlled environmental intervention.

Genome sequencing of drake semen micobiome with correlation with their compositions, sources and potential mechanisms affecting semen quality

Artificial insemination (AI) technology has greatly promoted the development of the chicken industry. Recently, AI technology has also begun to be used in the duck industry, but there are some problems. Numerous researchers have shown that microbes colonizing in semen can degrade semen quality, and AI can increase the harmful microbial load in hen's reproductive tract. Different from the degraded external genitalia of roosters, drakes have well-developed external genitalia, which may cause drake semen to be more susceptible to microbial contamination. However, information on the compositions, sources, and effects of semen microbes on semen quality remains unknown in drakes. In the current study, high-throughput sequencing technology was used to detect microbial communities in drake semen, environmental swabs, cloacal swabs, and the spermaduct after quantifying the semen quality of drakes to investigate the effects of microbes in the environment, cloaca, and spermaduct on semen microbiota and the relationships between semen microbes and semen quality. Taxonomic analysis showed that the microbes in the semen, environment, cloaca, and spermaduct samples were all classified into 4 phyla and 25 genera. Firmicutes and Proteobacteria were the dominant phyla. Phyllobacterium only existed in the environment, while Marinococcus did not exist in the cloaca. Of the 24 genera present in semen: Brachybacterium, Brochothrix, Chryseobacterium, Kocuria, Marinococcus, Micrococcus, Rothia, Salinicoccus, and Staphylococcus originated from the environment; Achromobacter, Aerococcus, Corynebacterium, Desemzia, Enterococcus, Jeotgalicoccus, Pseudomonas, Psychrobacter, and Turicibacter originated from the cloaca; and Agrobacterium, Carnobacterium, Chelativorans, Devosia, Halomonas, and Oceanicaulis originated from the spermaduct. In addition, K-means clustering analysis showed that semen samples could be divided into 2 clusters based on microbial compositions, and compared with cluster 1, the counts of Chelativorans (P < 0.05), Devosia (P < 0.01), Halomonas (P < 0.05), and Oceanicaulis (P < 0.05) were higher in cluster 2, while the sperm viability (P < 0.05), total sperm number (P < 0.01), and semen quality factor (SQF) (P < 0.01) were lower in cluster 2. Furthermore, functional prediction analysis of microbes showed that the activities of starch and sucrose metabolism, phosphotransferase system, ABC transporters, microbial metabolism in diverse environments, and quorum sensing pathways between cluster 1 and cluster 2 were significantly different (P < 0.05). Overall, environmental/cloacal microbes resulted in semen contamination, and microbes from the Chelativorans, Devosia, Halomonas, and Oceanicaulis genera may have negative effects on semen quality in drakes by affecting the activities of starch and sucrose metabolism, phosphotransferase system, ABC transporters, and quorum sensing pathways that are associated with carbohydrate metabolism. These data will provide a basis for developing strategies to prevent microbial contamination of drake semen.