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We report the results of taxonomic studies on members of the family Micrococcaceae that, according to the 16S rRNA, internal transcribed spacer 1 (ITS1), average nucleotide identity (ANI), and average amino acid identity (AAI) tests, are related to Kocuria rosea strain RCAM04488, a plant-growth-promoting rhizobacterium (PGPR) isolated from the rhizosphere of potato (Solanum tuberosum L.). In these studies, we used whole-genome phylogenetic tests and pangenomic analysis. According to the ANI > 95 % criterion, several known members of K. salina, K. polaris, and K. rosea (including K. rosea type strain ATCC 186T) that are related most closely to isolate RCAM04488 in the ITS1 test should be assigned to the same species with appropriate strain verification. However, these strains were isolated from strongly contrasting ecological and geographical habitats, which could not but affect their genotypes and phenotypes and which should be taken into account in evaluation of their systematic position. This contradiction was resolved by a pangenomic analysis, which showed that the strains differed strongly in the number of accessory and strain-specific genes determining their individuality and possibly their potential for adaptation to different ecological niches. Similar results were obtained in a full-scale AAI test against the UniProt database (about 250 million records), by using the AAI-profiler program and the proteome of K. rosea strain ATCC 186T as a query. According to the AAI > 65 % criterion, members of the genus Arthrobacter and several other genera belonging to the class Actinomycetes, with a very wide geographical and ecological range of sources of isolation, should be placed into the same genus as Kocuria. Within the paradigm with vertically inherited phylogenetic markers, this could be regarded as a signal for their following taxonomic reclassification. An important factor in this case may be the detailing of the gene composition of the strains and the taxonomic ratios resulting from analysis of the pangenomes of the corresponding clades.

Kuratsuki bacteria enter the sake production process and affect the flavor and taste of sake. This study compared gene expression in the sake yeast Saccharomyces cerevisiae in co-culture with kuratsuki Kocuria to that in monoculture. Among the 5922 genes of S. cerevisiae, 71 genes were upregulated more than 2-fold, and 61 genes were downregulated less than 0.5-fold in co-culture with kuratsuki Kocuria. Among the stress-induced genes, fourteen were upregulated, and six were downregulated. Among the fourteen upregulated genes, six were induced in response to replication stress. Although the G1 cyclin gene CLN3 was upregulated by more than 2-fold, eight genes that were induced in response to meiosis and/or sporulation were also upregulated. Fourteen metabolism-related genes, for example, the glyceraldehyde-3-phosphate dehydrogenase genes TDH1, TDH2, and TDH3, were downregulated by less than 0.5-fold in co-culture with kuratsuki Kocuria. The gene expression patterns of S. cerevisiae co-cultured with kuratsuki Kocuria differed from those co-cultured with lactic acid bacteria. Therefore, S. cerevisiae responded differently to different bacterial species. This strongly suggests that kuratsuki bacteria affect gene expression in sake yeast, thereby affecting the flavor and taste of sake. [ABSTRACT FROM AUTHOR]

Les auteurs rapportent deux cas cliniques de péritonite à Kocuria rhizophila, un germe peu fréquent mais pathogène, survenus dans un centre de dialyse sur une période de trois mois en 2022. Ces cas ont nécessité la dépose du cathéter de dialyse péritonéale, illustrant la gravité potentielle de ces infections. Les auteurs décrivent les caractéristiques clinico-biologiques de ces péritonites et soulignent la difficulté de distinguer Kocuria des autres cocci Gram positif, comme les staphylocoques, en raison de leur ressemblance morphologique, et la nécessité d’une identification précise pour un traitement approprié. La discussion aborde la fréquence et la gestion des péritonites à Kocuria en France, basée sur une étude observationnelle de cohorte utilisant les données du Registre de Dialyse Péritonéale de Langue Française (RDPLF) entre janvier 2018 et mai 2023. Cette étude a révélé que les péritonites à Kocuria représentaient 3,5% des péritonites documentées, Kocuria rhizophila étant le plus fréquemment identifié. L’étude met en évidence un taux important de récidives et la nécessité fréquente de retirer le cathéter, soulignant la gravité de ces infections. Conclusion : Les auteurs suggèrent qu’en cas de péritonite à Kocuria rhizophila, une dépose-repose rapide du cathéter pourrait être envisagée en raison du taux élevé de récidives. Ils appellent également à une vigilance accrue et à un suivi rapproché des patients traités conservativement par antibiothérapie pour minimiser le risque de récidive et d’échecs techniques, indiquant un besoin de stratégies thérapeutiques adaptées face à ce pathogène spécifique.

Simple Summary: The white poplar tree has great potential in greening cities and protecting the environment from pollution. However, planting poplars on contaminated soils can lead to suppression of poplar growth. To mitigate this problem, endophytes that stimulate plant growth and are able to degrade pollutants can be used. We studied the genomes of 14 different bacteria that live inside the roots of the white poplar tree and found that these bacteria have genes that help the tree grow and resist soil pollution. They contain genes that help the tree utilize important nutrients, produce beneficial chemicals, and get rid of harmful substances. The bacteria we studied are new strains of known bacterial species. The most promising are strains from the genera Pseudomonas and Kocuria. We believe that these endophytic bacteria can be used together with white poplar to better protect the environment. The white poplar (Populus alba L.) has good potential for a green economy and phytoremediation. Bioaugmentation using endophytic bacteria can be considered as a safe strategy to increase poplar productivity and its resistance to toxic urban conditions. The aim of our work was to find the most promising strains of bacterial endophytes to enhance the growth of white poplar in unfavorable environmental conditions. To this end, for the first time, we performed whole-genome sequencing of 14 bacterial strains isolated from the tissues of the roots of white poplar in different geographical locations. We then performed a bioinformatics search to identify genes that may be useful for poplar growth and resistance to environmental pollutants and pathogens. Almost all endophytic bacteria obtained from white poplar roots are new strains of known species belonging to the genera Bacillus, Corynebacterium, Kocuria, Micrococcus, Peribacillus, Pseudomonas, and Staphylococcus. The genomes of the strains contain genes involved in the enhanced metabolism of nitrogen, phosphorus, and metals, the synthesis of valuable secondary metabolites, and the detoxification of heavy metals and organic pollutants. All the strains are able to grow on media without nitrogen sources, which indicates their ability to fix atmospheric nitrogen. It is concluded that the strains belonging to the genus Pseudomonas and bacteria of the species Kocuria rosea have the best poplar growth-stimulating and bioaugmentation potential, and the roots of white poplar are a valuable source for isolation of endophytic bacteria for possible application in ecobiotechnology. [ABSTRACT FROM AUTHOR]

Kuratsuki bacteria enter the sake production process and affect the flavor and taste of sake. This study compared gene expression in the sake yeast Saccharomyces cerevisiae in co-culture with kuratsuki Kocuria to that in monoculture. Among the 5922 genes of S. cerevisiae, 71 genes were upregulated more than 2-fold, and 61 genes were downregulated less than 0.5-fold in co-culture with kuratsuki Kocuria. Among the stress-induced genes, fourteen were upregulated, and six were downregulated. Among the fourteen upregulated genes, six were induced in response to replication stress. Although the G1 cyclin gene CLN3 was upregulated by more than 2-fold, eight genes that were induced in response to meiosis and/or sporulation were also upregulated. Fourteen metabolism-related genes, for example, the glyceraldehyde-3-phosphate dehydrogenase genes TDH1, TDH2, and TDH3, were downregulated by less than 0.5-fold in co-culture with kuratsuki Kocuria. The gene expression patterns of S. cerevisiae co-cultured with kuratsuki Kocuria differed from those co-cultured with lactic acid bacteria. Therefore, S. cerevisiae responded differently to different bacterial species. This strongly suggests that kuratsuki bacteria affect gene expression in sake yeast, thereby affecting the flavor and taste of sake.

Dental disease in sugar gliders (Petaurus breviceps) is understudied, with only limited clinical and pathological data available. An approximately 7-year-old female sugar glider presented to its primary care veterinarian for a decline in food intake, rapid weight loss and a mass involving the rostral mandible. At necropsy, the mandibular mass effaced most of the rostral mandible and adjacent musculature. Histologically, the mandible was disrupted by nodular infiltrates of variably degenerate neutrophils and macrophages encased in granulomatous inflammation and fibrous connective tissue. Within the neutrophilic cell population were segments of fragmented, necrotic bone and cloud-like colonies of gram-positive cocci. Aerobic culture yielded a heavy, pure growth of a gram-positive coccus morphologically consistent with those identified in the lesions, which was identified as a presumptively novel Kocuria sp by polymerase chain reaction and sequencing of the 16S rRNA gene. This is the first description of Kocuria infection in association with clinically significant pathology in an animal. Although isolated as a pure growth, Kocuria sp cannot be confirmed as the sole cause of lesion formation due to the case chronicity and potential for unculturable, polymicrobial infections. This report adds to our understanding of the clinical and pathological aspects of dental disease in sugar gliders. [ABSTRACT FROM AUTHOR]

Kocuria species are catalase-positive and coagulase-negative Gram-positive coccoid bacteria that belong to the family Micrococcaceae, order Actinomycetales, and class Actinobacteria. Even though they may be relatively rare, they have been increasingly reported as the causes of human infections lately. The present study aims to review all published cases of Kocuria spp. infections in humans reporting data on epidemiology, microbiology, antimicrobial susceptibility, antimicrobial treatment, and mortality. A narrative review was performed based on a search of Pubmed and Scopus databases in the literature. In total, 73 studies provided data on 102 patients with Kocuria spp. infections. The mean age of patients was 47 years, and 68.3% were male. The most common types of infection were bacteremia (36.3%), skin and soft tissue infection (18.6%), endophthalmitis (15.7%), infective endocarditis (13.7%), and peritonitis (11.8%), most commonly peritoneal–dialysis-associated. The most frequently isolated species was K. kristinae (46.1%), and antimicrobial resistance was lower for vancomycin (7%) and tetracyclines (6.7%). Vancomycin (47%), cephalosporins (39.6%), and quinolones (36.6%) were the most commonly used antimicrobials. The empirical antimicrobial treatment of Kocuria spp. infections should include vancomycin as long as antimicrobial susceptibility results are pending. The infection outcome mainly depends on the type of infection and is higher for infective endocarditis. Endophthalmitis is associated with increased rates of low visual acuity after treatment. [ABSTRACT FROM AUTHOR]

Although sake yeast mainly produces the taste of sake, sake brewery-inhabiting (kuratsuki) bacteria affect the taste of sake. Thus, kuratsuki bacteria may alter the metabolism of sake yeast through interactions between kuratsuki bacteria and sake yeast. This study aimed to confirm the effects of the combination of kuratsuki Kocuria TGY1127_2 and different sake yeast strains, AK25, K901, and K1801 on the taste of sake. Although the Brix and acidity during sake production using AK25 differed between sake with and without kuratsuki Kocuria, those using K901 and K1801 did not differ. Thus, sake yeast AK25 interacted with kuratsuki Kocuria and changed its characteristics of ethanol fermentation. In addition, the taste intensity changes, measured with a taste sensor TS-5000Z, showed that the effects of adding kuratsuki Kocuria varied among different sake yeasts. Thus, each sake yeast strain interacted with the kuratsuki bacterium and produced different metabolites, resulting in a change in the taste of sake. The findings of this study can lead to the brewing of sake using different types of kuratsuki bacteria which can affect the taste of sake. [ABSTRACT FROM AUTHOR]

We present the first case report of prosthetic joint infection (PJI) caused by Kocuria rhizophila. Our patient is a 74-year-old male who underwent primary total hip replacement for right hip pain. His recovery was uneventful until 6 weeks postoperatively when he presented to his routine outpatient appointment with significant erythema, swelling, and tenderness over his right hip wound. Based on the acuity of his symptoms and the radiological findings, it was determined that the patient should undergo debridement, antibiotics, and implant retention (DAIR procedure). A consensus decision was also made at our PJI multidisciplinary meeting to treat him with 12 weeks of IV antibiotics. After completing this 12 weeks course of IV Vancomycin, his inflammatory markers returned to normal limits. At 6 months follow-up, our patient was mobilizing independently without any signs of infection recurrence. His radiographs showed the implant was in a satisfactory position with no evidence of loosening. This case adds to an emerging body of literature describing invasive infections associated with Kocuria species. We have demonstrated the effectiveness of managing this condition with debridement, implant retention, and IV Vancomycin therapy for 12 weeks. [ABSTRACT FROM AUTHOR]

Abstract Background Metal oxide nanoparticles (NPs) are becoming valuable due to their novel applications. The green synthesis of TiO2 NPs is more popular as a flexible and eco-friendly method compared to traditional chemical synthesis methods. TiO2 NPs are the most commonly used semiconductor in dye-sensitized solar cells (DSSCs). Results The biogenic TiO2 NPs were produced extracellularly by the marine halophilic bacterium Halomonas sp. RAM2. Response surface methodology (RSM) was used to optimize the biosynthesis process, resulting in a starting TiO2 concentration of 0.031 M and a pH of 5 for 92 min (⁓15 nm). TiO2 NPs were well-characterized after the calcination process at different temperatures of 500, 600, 700 and 800 °C. Anatase TiO2 NPs (calcined at 500 °C) with a smaller surface area and a wider bandgap were nominated for use in natural dye-sensitized solar cells (NDSSCs). The natural dye used as a photosensitizer is a mixture of three carotenoids extracted from the marine bacterium Kocuria sp. RAM1. NDSSCs were evaluated under standard illumination. After optimization of the counter electrode, NDSSCBio(10) (10 layers) demonstrated the highest photoelectric conversion efficiency (η) of 0.44%, which was almost as good as NDSSCP25 (0.55%). Conclusion The obtained results confirmed the successful green synthesis of TiO2 NPs and suggested a novel use in combination with bacterial carotenoids in DSSC fabrication, which represents an initial step for further efficiency enhancement studies.

Kocuria spp., are frequently documented members of the human microbiota and were formerly thought to be opportunistic bacteria, initiating infection only in immunocompromised patients. This study aimed to determine the prevalence of Kocuria species in samples from Iraqi pediatric patients, in addition to their sensitivity pattern. Bacterial identification was performed using a VITEK 2 device, and the Kirby-Bauer disk diffusion method was used to determine antibiotic susceptibility. Of 261 positive cultures, we found Kocuria isolates from 7 cases (2.68%). The mean age of the patients was 5.47 years, ranging from 4 months to 10 years; there were 3 males and 4 females. All patients had either urinary tract disease or symptomatic bacteremia. Vitek-2 identification using a gram-positive (GP) card revealed the presence of Kocuria kristinae in five cases, K. rhizophila in one case, and K. rosea in one case. Susceptibility of the Kocuria species isolates to amikacin, gentamicin and ceftazidime were demonstrated 100% resistance. In conclusion, Kocuria species, which are associated with serious clinical manifestations are an emerging health issue and further attention should be taken for appropriate management of antibiotic treatment as they are intrinsically multi-drug resistant.

Kocuria spp., possessing a powerful arsenal of pathogenicity factors, can cause severe septic conditions in humans under immunodepression. Therefore, it is important to determine the sensitivity of medically important Kocuria spp. to antibiotics. The aim of the study was to conduct a retrospective analysis of the sensitivity of clinical isolates of Kocuria spp. to antibiotics. During 2019-2022, 33 clinical isolates of Kocuria spp. were isolated from patients with odontogenic infectious and inflammatory diseases of the soft tissues of the face. Cultivation for the final identification of microorganisms was carried out according to the standard method. Determining the sensitivity of selected representatives of genus Kocuria to antibiotics was conducted using the disk diffusion method (Kirby-Bauer) according to EUCAST recommendations (v.12.0; 2022). In order to determine the groups of antibiotics to which Kocuria spp. maintain sensitivity, hierarchical cluster analysis was performed using Ward's method. Statistical analysis was performed using standard software IBM SPSS Statistics version 22.0. Among penicillins, representatives of this genus had the highest sensitivity to benzylpenicillin. The sensitivity of Kocuria isolates to cefotaxime and ceftazidime did not differ and was 51.5%. Representatives of genus Kocuria were highly sensitive to meropenem and vancomycin. As a result of research, Kocuria spp. was found to be moderately sensitive to gentamicin. Based on the cluster analysis of antibacterial drugs, according to the sensitivity of isolates of Kocuria spp. to them during 2019-2022, meropenem, benzylpenicillin, ceftazidime, cefotaxime, moxifloxacin, and ciprofloxacin with sensitivity higher than 50.0% were combined. Clinical isolates of Kocuria spp., isolated from patients with infectious and inflammatory diseases of the soft tissues of the face, showed variable sensitivity to all groups of antibacterial drugs during 2019-2022. Representatives of the genus Kocuria show the highest sensitivity to vancomycin. Today, clinical isolates of Kocuria spp. remain sensitive to meropenem, benzylpenicillin, ceftazidime, cefotaxime, moxifloxacin, and ciprofloxacin.

To the best of our knowledge, there are no studies on the effects of molecular hydrogen (H2) on microorganisms. In this study, we performed co-culture experiments using two microorganisms involved in sake brewing: sake yeast strain K1401 and the kuratsuki bacterium Kocuria strain TGY1127_2. The cells were suspended in water or water containing H2 and statically incubated at 4 °C for 2 h before co-culture. Sake taste was estimated using a taste sensor. The taste of sake was affected by H2 treatment of kuratsuki Kocuria as well as sake yeast. These results strongly suggest that H2 treatment alters the physiology of kuratsuki bacteria and sake yeast. We showed that sake undergoes H2 treatment of the microorganisms involved in sake brewing to boost its variety and meet the market demand. [ABSTRACT FROM AUTHOR]

Background: Metal oxide nanoparticles (NPs) are becoming valuable due to their novel applications. The green synthesis of TiO2 NPs is more popular as a flexible and eco-friendly method compared to traditional chemical synthesis methods. TiO2 NPs are the most commonly used semiconductor in dye-sensitized solar cells (DSSCs). Results: The biogenic TiO2 NPs were produced extracellularly by the marine halophilic bacterium Halomonas sp. RAM2. Response surface methodology (RSM) was used to optimize the biosynthesis process, resulting in a starting TiO2 concentration of 0.031 M and a pH of 5 for 92 min (⁓15 nm). TiO2 NPs were well-characterized after the calcination process at different temperatures of 500, 600, 700 and 800 °C. Anatase TiO2 NPs (calcined at 500 °C) with a smaller surface area and a wider bandgap were nominated for use in natural dye-sensitized solar cells (NDSSCs). The natural dye used as a photosensitizer is a mixture of three carotenoids extracted from the marine bacterium Kocuria sp. RAM1. NDSSCs were evaluated under standard illumination. After optimization of the counter electrode, NDSSCBio(10) (10 layers) demonstrated the highest photoelectric conversion efficiency (η) of 0.44%, which was almost as good as NDSSCP25 (0.55%). Conclusion: The obtained results confirmed the successful green synthesis of TiO2 NPs and suggested a novel use in combination with bacterial carotenoids in DSSC fabrication, which represents an initial step for further efficiency enhancement studies. [ABSTRACT FROM AUTHOR]

Kocuria is an anaerobic, Gram-positive bacterium, which has been rarely reported to cause endophthalmitis following cataract surgery, intravitreal injections, penetrating ocular trauma, and also secondary to endogenous sources. Visual prognosis is often guarded, with no previous cases reporting a final visual acuity better than 20/60. We describe a young female patient who developed culture-proven Kocuria kristinae endophthalmitis associated with a traumatic scleral rupture. Visual acuity at 2 months of follow-up improved from light perception to 20/50 after treatment with intravitreal antimicrobial therapy and pars plana vitrectomy.

The white poplar (Populus alba L.) has good potential for a green economy and phytoremediation. Bioaugmentation using endophytic bacteria can be considered as a safe strategy to increase poplar productivity and its resistance to toxic urban conditions. The aim of our work was to find the most promising strains of bacterial endophytes to enhance the growth of white poplar in unfavorable environmental conditions. To this end, for the first time, we performed whole-genome sequencing of 14 bacterial strains isolated from the tissues of the roots of white poplar in different geographical locations. We then performed a bioinformatics search to identify genes that may be useful for poplar growth and resistance to environmental pollutants and pathogens. Almost all endophytic bacteria obtained from white poplar roots are new strains of known species belonging to the genera Bacillus, Corynebacterium, Kocuria, Micrococcus, Peribacillus, Pseudomonas, and Staphylococcus. The genomes of the strains contain genes involved in the enhanced metabolism of nitrogen, phosphorus, and metals, the synthesis of valuable secondary metabolites, and the detoxification of heavy metals and organic pollutants. All the strains are able to grow on media without nitrogen sources, which indicates their ability to fix atmospheric nitrogen. It is concluded that the strains belonging to the genus Pseudomonas and bacteria of the species Kocuria rosea have the best poplar growth-stimulating and bioaugmentation potential, and the roots of white poplar are a valuable source for isolation of endophytic bacteria for possible application in ecobiotechnology.

Koji is made using steamed rice and a koji mold, which plays an essential role in sake brewing. We challenge to build a new sake brewing method using the kuratsuki bacteria that have inhabited each sake brewery. In this paper, effects of the kuratsuki Kocuria strain TGY1127_2 were estimated on sake brewing in different koji conditions. Sake was produced by incubation of a mixture solution of koji , water, and sake yeast (strain K1401) with and without the kuratsuki Kocuria TGY1127_2. The effects of the kuratsuki Kocuria on the taste of the sake differed among different koji. The kuratsuki Kocuria led to an increase in ethanol concentration. Additionally, the sugar content (Brix) and acidity of the sake increased in proportion to the amount of koji. These results strongly suggest that the kuratsuki Kocuria does not adversely affect the fermentation activity of the sake yeast. Thus, the kuratsuki Kocuria had different effects on the taste of sake among different koji but the fermentation activity of the sake yeast was maintained. [ABSTRACT FROM AUTHOR]

Kocuria spp., are frequently documented members of the human microbiota and were formerly thought to be opportunistic bacteria, initiating infection only in immunocompromised patients. This study aimed to determine the prevalence of Kocuria species in samples from iraqi pediatric patients, in addition to their sensitivity pattern. Bacterial identification was performed using a VITEK 2 device, and the Kirby-Bauer disk diffusion method was used to determine antibiotic susceptibility. Of 261 positive cultures, we found Kocuria isolates from 7 cases (2.68%). the mean age of the patients was 5.47 years, ranging from 4 months to 10 years; there were 3 males and 4 females. All patients had either urinary tract disease or symptomatic bacteremia. Vitek-2 identification using a gram-positive (GP) card revealed the presence of Kocuria kristinae in five cases, K. rhizophila in one case, and K. rosea in one case. Susceptibility of the Kocuria species isolates to amikacin, gentamicin and ceftazidime were demonstrated 100% resistance. in conclusion, Kocuria species, which are associated with serious clinical manifestations are an emerging health issue and further attention should be taken for appropriate management of antibiotic treatment as they are intrinsically multi-drug resistant. [ABSTRACT FROM AUTHOR]

Misidentifications of Kocuria and Rothia species often occur due to their overlapping traits, including similar cell shapes, biochemical characteristics and environmental preferences. These revisions aim to address significant overlaps and correct previous misidentifications. Phylogenetic analysis using 16S rRNA gene and core protein sequences has positioned Kocuria uropygioeca 257T and Kocuria uropygialis 36T within the genus Rothia . This reclassification is further substantiated by high 16S rRNA gene sequence similarities and average amino acid identity values, which align these species more closely with Rothia than with Kocuria . As a result, we propose the reclassification of 257T and 36T as Rothia uropygioeca comb. nov. and Rothia uropygialis comb. nov., respectively, to accurately reflect their taxonomic status. Additionally, average nucleotide identity and digital DNA-DNA hybridization values indicate that Kocuria marina KCTC 9943T and Kocuria indica DSM 25126T, as well as Kocuria rosea DSM 20447T and Kocuria polaris CMS 76orT, surpass the thresholds for subspecies classification. Therefore, we propose the recognition of four new subspecies: Kocuria marina subsp. marina comb. nov., Kocuria marina subsp. indica comb. nov., Kocuria rosea subsp. rosea comb. nov. and Kocuria rosea subsp. polaris comb. nov.

Kocuria species are catalase-positive and coagulase-negative Gram-positive coccoid bacteria that belong to the family Micrococcaceae, order Actinomycetales, and class Actinobacteria. Even though they may be relatively rare, they have been increasingly reported as the causes of human infections lately. The present study aims to review all published cases of Kocuria spp. infections in humans reporting data on epidemiology, microbiology, antimicrobial susceptibility, antimicrobial treatment, and mortality. A narrative review was performed based on a search of Pubmed and Scopus databases in the literature. In total, 73 studies provided data on 102 patients with Kocuria spp. infections. The mean age of patients was 47 years, and 68.3% were male. The most common types of infection were bacteremia (36.3%), skin and soft tissue infection (18.6%), endophthalmitis (15.7%), infective endocarditis (13.7%), and peritonitis (11.8%), most commonly peritoneal–dialysis-associated. The most frequently isolated species was K. kristinae (46.1%), and antimicrobial resistance was lower for vancomycin (7%) and tetracyclines (6.7%). Vancomycin (47%), cephalosporins (39.6%), and quinolones (36.6%) were the most commonly used antimicrobials. The empirical antimicrobial treatment of Kocuria spp. infections should include vancomycin as long as antimicrobial susceptibility results are pending. The infection outcome mainly depends on the type of infection and is higher for infective endocarditis. Endophthalmitis is associated with increased rates of low visual acuity after treatment.

A novel, mustard yellow-pigmented aerobic bacterial strain designated AR01T was isolated from hypocotyl tissue of a sandalwood seedling from Bangalore, India. The 16S rRNA gene of strain AR01T had the highest 98.97% sequence similarity with Rothia halotolerans YIM 90716T (KCTC 19172) followed by Rothia kristinae PM 129T (NBRC 15354T) (97.31%) and Rothia koreensis P31T (JCM 15915) (97.11%), respectively. The strain AR01T was coccoid-shaped, non-motile, non-spore forming, oxidase negative and catalase positive. The strain AR01T has a genome size of 3.31 Mb containing 2993 protein-coding genes including 48 tRNA and 10 rRNAs spread across 84 contigs. The genomic DNA G + C content was 71.77 mol%. The calculated dDDH was 31.10% and the OrthoANI value was 85.27% when compared with its closest related type strain Rothia halotolerans YIM 90716T. The predominant cellular fatty acids were C16:0 iso, C15:0 anteiso and C17:0 anteiso. The strain AR01T contains major polar lipids including diphosphatidylglycerol and phosphatidylglycerol. The distinct physiological, biochemical characteristics and genotypic relatedness indicated that AR01T represents a novel species of the genus Rothia, for which the name Rothia santali sp. nov. (Type strain AR01T = MCC 4800T = JCM 35593T) is proposed. [ABSTRACT FROM AUTHOR]

To expand the knowledge regarding the clinical presentation of Kocuria endophthalmitis. We included six cases of Kocuria endophthalmitis between January 2018 and December 2020. From all cases, we collected general demographic data, relevant medical, ophthalmological history, microbiological and antibiotic sensitivity results. All cases had a minimum follow-up of 9 months. All cases were treated with intravitreal moxifloxacin and dexamethasone and pars plana vitrectomy. Undiluted vitreous, corneal, conjunctival, and aqueous samples were cultured and analyzed with the Vitek 2 system. The prevalence of Kocuria endophthalmitis was 6%. (95%CI: 2.26%-12.73%). The mean age at diagnosis was 60.5 ± 15.5 years. All patients had poor visual acuity, severe pain, and severe conjunctival hyperemia at diagnosis. Only one case had a significant improvement in visual acuity at the end of the follow-up. Kocuria spp are an emerging cause of endophthalmitis and should be considered as part of the differential diagnosis. [ABSTRACT FROM AUTHOR]

With the increased usage of nitrate fertilizers, the removal of their stable ionic and water-soluble end products is a challenge for human health. Several physicochemical methods have been examined for nitrate removal of water, but biological treatments are mostly preferred due to a higher efficiency and lower cost. To remove nitrogen from water, we investigated the potential of nitrate-reducing halophilic and halotolerant bacteria. A total of 50 strains from different saline and hypersaline environments of Iran, including the Incheboron wetland, Aran-Bidgol salt-lake, and Urmia endorheic salt-lake, were screened for nitrate reductase production. Among investigated bacteria, 60% and 19% of strains obtained from Urmia lake, and Incheboron wetland produced nitrate reductases, respectively. The nitrate reductase coding genes narG, and napA were analyzed in all strains with confirmed nitrate-reducing capacity. The napA gene was successfully amplified from a gram-negative halophilic strain, and the narG gene was detected in ten halophilic strains. Among nitrate-reducing isolates with the narG gene expression, the Kocuria rosea strain R3A34 showed the highest nitrate reductase production level. This strain was selected to optimize for its denitrifying activity. Results showed that 32°C, pH 7.0, NaCl 8% (w/v), and mannitol (as a carbon source) provide the optimal environmental conditions for the efficient production of nitrate reductase by the Kocuria rosea strain R3A34. As these are compatible with wastewaters conditions, this bacterium can be a proper candidate for bioremediation of wastewaters from nitrate pollutants.

To the best of our knowledge, there are no studies on the effects of molecular hydrogen (H2) on microorganisms. In this study, we performed co-culture experiments using two microorganisms involved in sake brewing: sake yeast strain K1401 and the kuratsuki bacterium Kocuria strain TGY1127_2. The cells were suspended in water or water containing H2 and statically incubated at 4 °C for 2 h before co-culture. Sake taste was estimated using a taste sensor. The taste of sake was affected by H2 treatment of kuratsuki Kocuria as well as sake yeast. These results strongly suggest that H2 treatment alters the physiology of kuratsuki bacteria and sake yeast. We showed that sake undergoes H2 treatment of the microorganisms involved in sake brewing to boost its variety and meet the market demand.

Kocuria is an anaerobic, Gram-positive bacterium, which has been rarely reported to cause endophthalmitis following cataract surgery, intravitreal injections, penetrating ocular trauma, and also secondary to endogenous sources. Visual prognosis is often guarded, with no previous cases reporting a final visual acuity better than 20/60. We describe a young female patient who developed culture-proven Kocuria kristinae endophthalmitis associated with a traumatic scleral rupture. Visual acuity at 2 months of follow-up improved from light perception to 20/50 after treatment with intravitreal antimicrobial therapy and pars plana vitrectomy. [ABSTRACT FROM AUTHOR]

Bacteria belonging to the genus Kocuria were identified as bacteria peculiar to a sake brewery in Toyama, Japan. Comparison of the 16S rRNA gene sequences revealed two groups of Kocuria isolates. Among known species, one group was similar to K. koreensis (Kk type), and the other, K. uropygioeca (Ku type). We determined complete genomic DNA sequences from two isolates, TGY1120_3 and TGY1127_2, which belong to types Kk and Ku, respectively. Comparison of these genomic information showed that these isolates differ at the species level with different genomic characters. Isolate TGY1120_3 comprised one chromosome and three plasmids, and the same transposon coding region was located on two loci on the chromosome and one locus on one plasmid, suggesting that the genetic element may be transferred between the chromosome and plasmid. Isolate TGY1127_2 comprised one chromosome and one plasmid. This plasmid encoded an identical transposase coding region, strongly suggesting that the genetic element may be transferred between these different isolates through plasmids. These four plasmids carried a highly similar region, indicating that they share a common ancestor. Thus, these two isolates may form a community and exchange their genetic information during sake brewing.

Chemical investigation of secondary metabolites from a marine-derived actinomycete strain of the genus Kocuria, isolated from a stony coral Mycedium sp., led to the identification of two new alkanoylimidazoles, nocarimidazoles C (1) and D (2) as well as three known congeners, nocarimidazoles A (3) and B (4) and bulbimidazole A (5). Structure analysis of 1 and 2 by NMR and MS revealed that both are 4-alkanoyl-5-aminoimidazoles with a 6-methyloctanoyl or decanoyl chain, respectively. Two possible positions of the amino group on the imidazole rings (C-2 and C-5) posed a challenge in the structure study, which was settled by the measurement of 1JC,H coupling constants for comparison with those of synthetically prepared model imidazoles. The absolute configurations of the anteisoalkanoyl group present in 1, 4, and 5 were determined by low-temperature HPLC analysis of the degradation products labeled with a chiral anthracene reagent, which revealed that 1 is a mixture of the R- and S-enantiomers with a ratio of 73:27, 4 is the pure (S)-enantiomer, and 5 is the (S)-enantiomer with 98% ee. The present study illustrates the diversity in the stereochemistry of anteiso branching in bacterial metabolites. Compounds 1−4 were moderately antimicrobial against Gram-positive bacteria and fungi, with MIC ranges of 6.25–25 μg/mL.

With the increased usage of nitrate fertilizers, the removal of their stable ionic and water-soluble end products is a challenge for human health. Several physicochemical methods have been examined for nitrate removal of water, but biological treatments are mostly preferred due to a higher efficiency and lower cost. To remove nitrogen from water, we investigated the potential of nitrate-reducing halophilic and halotolerant bacteria. A total of 50 strains from different saline and hypersaline environments of Iran, including the Incheboron wetland, Aran-Bidgol salt-lake, and Urmia endorheic salt-lake, were screened for nitrate reductase production. Among investigated bacteria, 60% and 19% of strains obtained from Urmia lake, and Incheboron wetland produced nitrate reductases, respectively. The nitrate reductase coding genes narG, and napA were analyzed in all strains with confirmed nitrate-reducing capacity. The napA gene was successfully amplified from a gram-negative halophilic strain, and the narG gene was detected in ten halophilic strains. Among nitrate-reducing isolates with the narG gene expression, the Kocuria rosea strain R3A34 showed the highest nitrate reductase production level. This strain was selected to optimize for its denitrifying activity. Results showed that 32°C, pH 7.0, NaCl 8% (w/v), and mannitol (as a carbon source) provide the optimal environmental conditions for the efficient production of nitrate reductase by the Kocuria rosea strain R3A34. As these are compatible with wastewaters conditions, this bacterium can be a proper candidate for bioremediation of wastewaters from nitrate pollutants. [ABSTRACT FROM AUTHOR]

This study aims to assess the effect of five endophytic bacteria on the growth promotion of tomato plants under salt stress conditions. Twenty-five endophytic bacteria were isolated from roots of the native halophyte Stipa tenacissima L. collected from Djelfa (Algeria) and were evaluated for their halotolerant potential. Seven strong halotolerant isolates were selected and characterized for in vitro Plant Growth Promotion (PGP) including the ACC-deaminase activity, inorganic phosphate solubilization and the production of indole-3-acetic acid and siderophores. Five strains showing high PGP traits were investigated for the mitigation of salt stress and PGP of tomato (Solanum esculentum L. cv. Aïcha). Screening of the salt-tolerant isolates for PGP traits in saline condition (75 mM NaCl) under Petri-dishes experiment of tomato revealed that three isolates ST09, ST18 and ST19 improved the growth of tomato seedlings by highlighting germination rate, shoot and root lengths and biomass. Under greenhouse conditions at 0 and 75 mM NaCl, inoculation of strains ST09, ST18 and ST19 in tomato seedlings produced an increase in germination (69.23%, 73.07% and 73.07%). The isolate ST19 showed an increase of more than 90% in root elongation and 17.4% increase in biomass when compared to uninoculated tomato seedlings at 75 mM NaCl stress. Phylogenetic analysis based on the 16S rRNA gene showed that the strain ST19 belongs to the genus Kocuria , and is closely related to Kocuria arsenatis |CM1E1|KM874399T (99.29% similarity). Thus, we conclude that the inoculation of tomato plants with the strain ST19 showed its efficiency to mitigate salt stress conditions. [ABSTRACT FROM AUTHOR]

Kocuria isolates collected from the sake brewing process have inhabited the Narimasa Sake Brewery in Toyama, Japan. To investigate the effect of these actinobacterial isolates on the growth and metabolism of sake yeast, co-cultivation of sake yeast and Kocuria isolates was performed in a medium containing tryptone, glucose and yeast extract (TGY), and a solution containing koji (steamed rice covered with Aspergillus oryzae) and glucose. In the TGY medium, the ethanol concentration and the number of living cells of each microorganism were measured. In the koji solution, the concentrations of ethanol and organic acids (citric acid, lactic acid and succinic acid) were measured. The results showed that in TGY media, the growth of each Kocuria isolate in the co-culture of the two Kocuria isolates was similar to that in each monoculture. However, the growth of both Kocuria isolates was inhibited in the co-cultures of sake yeast and Kocuria isolates. On the other hand, the growth and ethanol productivity of sake yeast did not differ between its monoculture and co-cultures with Kocuria isolates. In the koji solution, Kocuria isolates TGY1120_3 and TGY1127_2 affected the concentrations of ethanol and lactic acid, respectively. Thus, Kocuria isolates affected the microbial metabolism, but the effects were not identical between the two isolates. This strongly suggests that bacteria inhabiting a sake brewery may influence the flavor and taste of sake products of the brewery. [ABSTRACT FROM AUTHOR]

We report the results of taxonomic studies on members of the family Micrococcaceae that, according to the 16S rRNA, internal transcribed spacer 1 (ITS1), average nucleotide identity (ANI), and average amino acid identity (AAI) tests, are related to Kocuria rosea strain RCAM04488, a plant-growth-promoting rhizobacterium (PGPR) isolated from the rhizosphere of potato (Solanum tuberosum L.). In these studies, we used whole-genome phylogenetic tests and pangenomic analysis. According to the ANI > 95 % criterion, several known members of K. salina, K. polaris, and K. rosea (including K. rosea type strain ATCC 186T) that are related most closely to isolate RCAM04488 in the ITS1 test should be assigned to the same species with appropriate strain verification. However, these strains were isolated from strongly contrasting ecological and geographical habitats, which could not but affect their genotypes and phenotypes and which should be taken into account in evaluation of their systematic position. This contradiction was resolved by a pangenomic analysis, which showed that the strains differed strongly in the number of accessory and strain-specific genes determining their individuality and possibly their potential for adaptation to different ecological niches. Similar results were obtained in a full-scale AAI test against the UniProt database (about 250 million records), by using the AAI-profiler program and the proteome of K. rosea strain ATCC 186T as a query. According to the AAI > 65 % criterion, members of the genus Arthrobacter and several other genera belonging to the class Actinomycetes, with a very wide geographical and ecological range of sources of isolation, should be placed into the same genus as Kocuria. Within the paradigm with vertically inherited phylogenetic markers, this could be regarded as a signal for their following taxonomic reclassification. An important factor in this case may be the detailing of the gene composition of the strains and the taxonomic ratios resulting from analysis of the pangenomes of the corresponding clades., Competing Interests: The authors declare no conflict of interest., (Copyright © AUTHORS.)

The uropygial gland (preen gland) of birds plays an important role in maintaining feather integrity and hygiene. Although a few studies have demonstrated potential defensive roles of bacteria residing within these glands, the diversity and functions of the uropygial gland microbiota are largely unknown. Therefore, we investigated the microbiota of great tit (Parus major) uropygial glands through both isolation of bacteria (culture-dependent) and 16S rRNA amplicon sequencing (culture-independent). Co-culture experiments of selected bacterial isolates with four known feather-degrading bacteria (Bacillus licheniformis, Kocuria rhizophila, Pseudomonas monteilii, and Dermacoccus nishinomiyaensis), two non-feather degrading feather bacteria, one common soil bacterial pathogen and two common fungal pathogens enabled us to evaluate the potential antimicrobial properties of these isolates. Our results show major differences between bacterial communities characterized using culture-dependent and -independent approaches. In the former, we were only able to isolate 12 bacterial genera (dominated by members of the Firmicutes and Actinobacteria), while amplicon sequencing identified 110 bacterial genera (dominated by Firmicutes, Bacteroidetes, and Proteobacteria). Uropygial gland bacterial isolates belonging to the genera Bacillus and Kocuria were able to suppress the growth of four of the nine tested antagonists, attesting to potential defensive roles. However, these bacterial genera were infrequent in our MiSeq results suggesting that the isolated bacteria may not be obligate gland symbionts. Furthermore, bacterial functional predictions using 16S rRNA sequences also revealed the ability of uropygial gland bacteria to produce secondary metabolites with antimicrobial properties, such as terpenes. Our findings support that uropygial gland bacteria may play a role in feather health and that bacterial symbionts might act as defensive microbes. Future investigations of these bacterial communities, with targeted approaches (e.g., bacterial isolation and chemical analyses), are thus warranted to improve our understanding of the evolution and function of these host-microbe interactions.

Abstract Aim To describe the clinical presentations and management outcomes of Kocuria endophthalmitis and discuss diagnostic dilemmas Design Retrospective interventional comparative case series Intervention Eight unilateral cases with culture-proven Kocuria endophthalmitis from January 2013 to December 2017 underwent vitrectomy/vitreous biopsy and intravitreal antibiotic with or without additional procedures. The undiluted vitreous was subjected to microbiologic evaluation. Main outcome measures The mean age at presentation, etiology, number of interventions, interval between inciting event and presentation, type of intravitreal antibiotic used, and anatomic and functional outcomes were reported. A favorable anatomic outcome was defined as preservation of the globe, absence of hypotony, attached retina, and absence of active inflammation at the last visit. Results In the current series, there were five males and three females. The mean age at presentation was 31 ± 17.44 years (median 30 years). The inciting event was open globe injury in five cases and one case each following cataract surgery, microbial keratitis, and endogenous cause. Visual acuity was ≥ 20/400 in one case at presentation and ≥ 20/400 in three cases at the last visit. The species identified by Vitek 2, included Kocuria kristinae in three, K. rosea in four and K. varians in one. Follow-up period was 8.25 ± 8.24 months (median 6.5). Six cases (75%) had complete resolution of infection and inflammation at the last visit. Anatomic success was achieved in 75%. Conclusions Kocuria is a relatively rare cause of endophthalmitis often misdiagnosed as Staphylococcal endophthalmitis. Clinical presentation can be variable but favorable antibiotic susceptibility and appropriate timely management can result in acceptable visual and anatomic outcomes.

Introduction: The inevitable rise of antibiotic-resistant bacteria is a global health problem. These pathogens erode the utility of available antibiotics. Staphylococcus aureus is one of the major causes of community-acquired infections. The aim of work was to evaluate the marine actinomycetes for production of the antibacterial agent against pathogens. Methods: Halophilic actinomycetes were isolated, characterized and screened for production of antibacterial agent against pathogenic bacteria. The antibacterial compounds were extracted by solvent extraction and separated by TLC based bioautography. Antibacterial compound was further purified by flash chromatography followed by high-performance liquid chromatography (HPLC) techniques. The active fraction was characterized by spectroscopy techniques. The minimum inhibitory concentration of antibiotic was determined against pathogens. Results: A new halophilic actinomycetes strain rsk4 was isolated from marine water. It was designated as Kocuria sp. based on the physiological, biochemical and 16S rDNA sequencebased characters. It was able to produce broad-spectrum antibacterial compound and exhibited significant inhibitory activities against antibiotic-resistant S. aureus. The antibacterial compound was secreted optimally at 5% NaCl and neutral pH in the starch casein medium during stationary phase. The crude ethyl acetate extract was separated by chloroform-methanol, 24:1, v/v having Rf value 0.45. Bioassay of HPLC fractions confirms the presence of antibiotics picks at retention time: 3.24 minutes. The UV-Visible and mass spectra of the compound revealed that the active compound was different from other known antibiotics. The lowest minimum inhibitory concentration was recorded against S. aureus (30 µg/mL). Conclusion: The result suggests that a broad-spectrum antibacterial compound obtained from halophilic actinomycetes is effective against pathogenic bacteria. This compound may be a good alternative treatment against antibiotic-resistant pathogen S. aureus.

Signifi cant brewery species of micrococcus were reclassifi ed to the genus Kocuria: Kocuria kristinae (previously Micrococcus kristinae) and Kocuria varians (previously Micrococcus varians). Bacteria of genus Kocuria belong to less risky microbial contaminants of beer and brewery plant. Species Kocuria kristinae may exceptionally cause beer spoilage. Signifi cant is their misplacement for pediococci. Here we present an overview of basic morphological and physiological properties of Kocuria (Micrococcus) species and describe their harmfulness in the brewing process.

The uropygial gland (preen gland) of birds plays an important role in maintaining feather integrity and hygiene. Although a few studies have demonstrated potential defensive roles of bacteria residing within these glands, the diversity and functions of the uropygial gland microbiota are largely unknown. Therefore, we investigated the microbiota of great tit (Parus major) uropygial glands through both isolation of bacteria (culture-dependent) and 16S rRNA amplicon sequencing (culture-independent). Co-culture experiments of selected bacterial isolates with four known feather-degrading bacteria (Bacillus licheniformis , Kocuria rhizophila , Pseudomonas monteilii , and Dermacoccus nishinomiyaensis), two non-feather degrading feather bacteria, one common soil bacterial pathogen and two common fungal pathogens enabled us to evaluate the potential antimicrobial properties of these isolates. Our results show major differences between bacterial communities characterized using culture-dependent and -independent approaches. In the former, we were only able to isolate 12 bacterial genera (dominated by members of the Firmicutes and Actinobacteria), while amplicon sequencing identified 110 bacterial genera (dominated by Firmicutes, Bacteroidetes, and Proteobacteria). Uropygial gland bacterial isolates belonging to the genera Bacillus and Kocuria were able to suppress the growth of four of the nine tested antagonists, attesting to potential defensive roles. However, these bacterial genera were infrequent in our MiSeq results suggesting that the isolated bacteria may not be obligate gland symbionts. Furthermore, bacterial functional predictions using 16S rRNA sequences also revealed the ability of uropygial gland bacteria to produce secondary metabolites with antimicrobial properties, such as terpenes. Our findings support that uropygial gland bacteria may play a role in feather health and that bacterial symbionts might act as defensive microbes. Future investigations of these bacterial communities, with targeted approaches (e.g., bacterial isolation and chemical analyses), are thus warranted to improve our understanding of the evolution and function of these host-microbe interactions. [ABSTRACT FROM AUTHOR]

Sir, We read with interest the case report “Endocarditis bacteriana por Kocuria kristinae en un paciente inmunocompetente. Reporte de caso” by S.M. Rojas Molina, et al1 . The authors described about the Kocuria kristinae endocarditis in an immunocompetent woman. We agree that Kocuria kristinae is a rare organism and endocarditis caused by this organism is worth mentioning. However, there are certain questionable points in the report which we would wish to highlight and which need clarification.

This publication is a sequel to the study Microbiology of brewing – Kocuria (Micrococcus) and cultivation methods for their detection – part 1 (Matoulková and Kubizniaková, Kvasny Průmysl 64(1): 10–13, 2018). Growth was monitored in a set of 8 strains of Kocuria and Micrococcus on solidified culture media, e.g. MRS agar and its various modifications, the media Raka-Ray, NBB, UBA, etc. Under aerobic conditions, most strains of Kocuria were able to grow on UBA agar, which is designed to detect beer harmful microorganisms. Thus there is a higher likelihood of confusion of Kocuria with more risky Pediococcus and vice versa in laboratories, which do not apply anaerobic incubation conditions to detect lactic acid bacteria.

In this work, bioaccumulation and biosorption characteristics of Cd2+ ions by both dead and living non-growing biomass of gram-positive bacteria Kocuria palustris and Micrococcus luteus isolated from spent nuclear fuel pools were compared. The radioindicator method with radionuclide 109Cd was used to obtain precise and reliable data characterizing Cd compartmentalization in bacterial cells. The following cellular distribution of Cd in living non-growing biomass after 4 h incubation in solutions containing different concentration of Cd2+ ions (100, 250, 500, 750 and 1000 µmol/L) spiked with 109CdCl2 under aeration at 30 °C were obtained: in M. luteus almost 85 % of Cd was localized on the cell surface and 15 % in cytoplasm. Similarly, in K. palustris 83 % of Cd was localized on the cell surface and 17 % in cytoplasm. The data were obtained by gamma spectrometry of extracts and solids after sequential extraction of biomass with 5 mM Ca(NO3)2 and 20 mM EDTA. Biosorption of Cd by non-living bacterial biomass is a rapid process strongly affected by solution pH and as was confirmed by FTIR analysis beside carboxylate ions also other functional groups such as amino and phosphate contribute to Cd binding by bacterial cell surfaces. Maximum sorption capacities Qmax (μmol/g) calculated from the Langmuir isotherm were 444 ± 15 μmol/g for M. luteus and 381 ± 1 μmol/g for K. palustris.

Introduction: The formation of bacterial biofilms by opportunistic microorganisms on the surfaces of the implants is the leading etiopathogenetic factor of peri-implant mucositis and peri-implantitis. The purpose of this research was to study the adhesive and biofilm-forming properties of clinical strains of K. kristinae isolated from patients with peri-implant mucositis. Methods: 18 clinical strains of K. kristinae isolated from the patients were the object of the study. The adhesion of the microorganisms was determined by using formalized human red blood cells of the blood group O (1) Rh+ by the G. Brilis technique. The study of biofilm-forming properties of clinical isolates of K. kristinae was performed by using the spectrophotometric technique by G.D. Christensen (MtP microtiter plate test). Results: The representatives of genus Kocuria were isolated in 70% of patients. Total proportion of clinical isolates of Kocuria spp. among all isolated microorganisms reached 18.3%. The representatives of the species K. kristinae showed a high adhesion to red blood cells and high ability to form biofilms. The r-Pearson coefficient (+0.87) between adhesion and the ability to form biofilms by K. kristinae strains pointed out a direct correlation. Conclusions: Obviously, Kocuria spp. take part in peri-implant mucositis development. It is proved by their presence on the mucous membrane of peri-implant area of patients with complications after dental implant placement. The representatives of the species K. kristinae showed a high adhesion and high biofilmformation. [ABSTRACT FROM AUTHOR]

Introduction : The inevitable rise of antibiotic-resistant bacteria is a global health problem. These pathogens erode the utility of available antibiotics. Staphylococcus aureus is one of the major causes of community-acquired infections. The aim of work was to evaluate the marine actinomycetes for production of the antibacterial agent against pathogens. Methods : Halophilic actinomycetes were isolated, characterized and screened for production of antibacterial agent against pathogenic bacteria. The antibacterial compounds were extracted by solvent extraction and separated by TLC based bioautography. Antibacterial compound was further purified by flash chromatography followed by high-performance liquid chromatography (HPLC) techniques. The active fraction was characterized by spectroscopy techniques. The minimum inhibitory concentration of antibiotic was determined against pathogens. Results : A new halophilic actinomycetes strain rsk4 was isolated from marine water. It was designated as Kocuria sp. based on the physiological, biochemical and 16S rDNA sequencebased characters. It was able to produce broad-spectrum antibacterial compound and exhibited significant inhibitory activities against antibiotic-resistant S. aureus. The antibacterial compound was secreted optimally at 5% NaCl and neutral pH in the starch casein medium during stationary phase. The crude ethyl acetate extract was separated by chloroform-methanol, 24:1, v/v having Rf value 0.45. Bioassay of HPLC fractions confirms the presence of antibiotics picks at retention time: 3.24 minutes. The UV-Visible and mass spectra of the compound revealed that the active compound was different from other known antibiotics. The lowest minimum inhibitory concentration was recorded against S. aureus (30 µg/mL). Conclusion : The result suggests that a broad-spectrum antibacterial compound obtained from halophilic actinomycetes is effective against pathogenic bacteria. This compound may be a good alternative treatment against antibiotic-resistant pathogen S. aureus. [ABSTRACT FROM AUTHOR]

Background: Diverse aquatic microorganisms are capable of colonizing living and non-living surfaces leading to the formation of biofilms. Commonly visualized as a slimy layer, these biofilms are filled with hundreds of other microorganisms compared to free living planktonic cells. Microbial surface colonization and surface-associated metabolic activities also exert several macroscale deleterious effects, including biofouling, biocorrosion and the persistence and transmission of harmful or pathogenic microorganisms and virulence determinants. The present study deals with the isolation and screening of marine bacteria for biofilm formation. The screened isolates were characterized and identified as Pychrobacter celer, Pychrobacter alimentarius and Kocuria rhizophila by 16S rRNA sequencing.Methods: Biofilm forming bacteria were isolated by spread plate technique and subjected to screening by microtiter plate assay. The potent biofilm formers were identified by molecular characterization using 16S rRNA gene sequencing.Results: Twelve bacterial isolates were obtained by pour plate technique and subjected to biofilm assay. Among the 12 isolates three isolates which showed maximum biofilm formation were subjected to molecular characterizationby 16S rRNA gene sequencing method. The isolates were identified as Pychrobacter celer, Pychrobacter alimentarius and Kocuria rhizophila. The EPS produced by the three biofilm forming bacteria was extracted and the protein and carbohydrate content determined.Conclusion: Among the isolates screened, isolate 8 (Kocuria rhizophila) produced maximum protein and carbohydrate which was also in accordance with the results of microtiter plate assay. [ABSTRACT FROM AUTHOR]

An attempt was made to identify actinobacterial strains present in the marine soil of East Coast regions viz., Chirala, Bapatla, and Peddaganjam, Andhra Pradesh; Kanyakumari, Tamil Nadu and Goa, Goa along with the study of their antimicrobial potential. Eight out of 73 actinobacterial strains isolated from these regions showed strong antimicrobial activity against Gram positive bacteria, Gram negative bacteria, and Candida albicans. Molecular identification (16S rRNA analysis) of the eight strains revealed that they belong to Dietzia sp., Kocuria sp., Nocardiopsis sp., and Streptomyces spp. ISP (International Streptomyces project) -1, ISP-2 and starch casein media supported high antimicrobial potential after 5–6 days of growth. Production of antimicrobials by the strains varied significantly with different carbon and nitrogen sources. Gas chromatography mass spectrometry (GCMS) analysis of volatile compounds produced by the strains illustrated an array of antimicrobial compounds such as 1, 2-benzene dicarboxylic acid, 2-piperidinone, pyrrolo[1,2-a]pyrazine-1,4-dion, phenyl ethyl alcohol, 3-phenyl propionic acid etc. Ours is the first report on the study and detection of above mentioned antimicrobial metabolites from Dietzia sp. (A3), Kocuria sp. (A5), and Nocardiopsis sp. (A7). By sequence based analysis for secondary metabolites, non-ribosomal peptide synthetase (NRPS) gene cluster was noticed in six strains (A2, A3, A4, A6, A7, and A8) and none of them had polyketide synthase (PKS) system. The present study intimates the biological potentiality of the actinobacterial strains isolated from East Coast of Andhra Pradesh, India which reveals further scope to investigate new bioactive compounds from them by employing both natural product chemistry and modern biotechnological aspects.