Infection structures were observed at the penetration sites on the leaves of cucumber plants inoculated with Colletotrichum orbiculare using a fluorescence microscope. The cucumber plants were previously drenched with suspension of bacterial strains Pseudomonas putida or Micrococcus luteus. The plants pre-inoculated with both bacterial strains were resistant against anthracnose after inoculation with C. orbiculare. To investigate the resistance mechanism by both bacterial strains, the surface of infected leaves was observed at the different time after challenge inoculation. At 3 days after inoculation there were no differences in the germination and appressorium formation of conidia of C. orbiculare as well as in the callose formation of the plants between both bacteria pre-inoculated and non-treated. At 5 days, the germination and appressorium formation of the fungal conidia were, however, significantly decreased on the leaves of plants pre-inoculated with M. luteus at the concentration with 1.0 x 10(7) cfu/ml. Furthermore, callose formation of plants cells at the penetration sites was apparently increased. In contrast, there were no defense reactions of the plants at the concentration with 1.0 x 10(6) cfu/ml of M. luteus. Similarly, inoculation P. putida caused no plant resistance at the low concentration, whereas increase of callose formation was observed at the higher concentration. The results of this study suggest that the resistant mechanisms might be differently expressed by the concentration of pre-treatment with bacterial suspension.
Bacteria ; Colletotrichum* ; Fluorescence ; Germination ; Micrococcus luteus* ; Micrococcus* ; Plants ; Pseudomonas putida* ; Pseudomonas* ; Spores, Fungal

Efficacy of resistance induction by the bacterial isolates Pseudomonas putida (TRL2-3), Micrococcus luteus (TRK2-2) and Flexibacteraceae bacterium (MRL412), which were isolated from the rhizosphere of plants growing in Jeju Mountain, were tested in a greenhouse. The disease severity caused by Phytophthora infestans was effectively reduced in the potato plants pre-inoculated with bacterial isolates compared with those of the untreated control plants growing in a greenhouse. In order to estimate the level of protection by the bacterial isolates, Mancozeb WP (Diesen M(R), Kyong nong) and DL-3-amino butyric acid (BABA) were pre-treated, whereas Dimethomorph WP (Forum(R), Kyong nong) and phosphonic acid (H3PO3) were post-treated the challenge inoculation with the pathogen. Disease severities of chemical pre-treated as well as post-treated plants were reduced compare to those of the untreated. The disease reduction in the plants pre-treated with Mancozeb WP was the highest, whereas that of post-treated with Dimethomorph WP was the lowest. The yields of plants pre-inoculated with three bacterial isolates were greatly increased than those of control plants. These results suggest that biological control by bacterial isolates might be an alternative strategy against late blight disease in potato plants growing in greenhouse.
Butyric Acid ; Cytophagaceae ; Micrococcus luteus ; Phytophthora infestans* ; Phytophthora* ; Pseudomonas putida ; Rhizosphere ; Solanum tuberosum*

Polyhydroxyalkanoates (PHAs), as a novel class of biopolymer, are attracting more attention due to their diverse material properties and environment-independent biodegradability. Here we report the preparation of PHA exhibiting efficient antibacterial activity by embedding Nisin, a food additive generally recognized as safe, into poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx), a type of PHA with high biocompatibility. We first prepared Nisin-containing PHBHHx films using solvent casting method. Confocal laser scanning microscopy analysis showed that a well-mixed integrated structure of the films with an even distribution of the Nisin particles in the PHBHHx matrices. Then the antimicrobial activity of PHBHHx/Nisin films against Micrococcus luteus was quantified on agar plate by measuring the size of inhibition zone. Cultivation in liquid media further confirmed the releasing of Nisin from the films and the long-time antibacterial activity. Results showed that the threshold of Nisin concentration for long-time and effective inhibition against bacteria growth is 25 μg/g. These results altogether establish a technological foundation for the application of PHA in biomedicine and food industry.
3-Hydroxybutyric Acid ; chemistry ; Anti-Bacterial Agents ; chemistry ; Caproates ; chemistry ; Micrococcus luteus ; drug effects ; Nisin ; chemistry ; Polyhydroxyalkanoates ; chemistry

The objective of this study is to propose a more accurate and faster MTT [3-(4,5-dimethyl thiazol-2-yl)-2,5-diphenyl tetrazolium bromide] colorimetric assay (MCA) for quantitative measurement of polypeptide bacteriocins in solutions with nisin as an example. After an initial incubation of nisin and indicator bacterium Micrococcus luteus NCIB 8166 in tubes, MTT was added for another incubation period. After that, nisin was quantified by estimating the number of viable bacteria based on measuring the amount of purple formazan produced by cleavage of yellow tetrazolium salt MTT. Then MCA was compared to a standard agar diffusion assay (ADA). The results suggested a high correlation coefficient (r(2)=0.975+/-0.004) between optical density (OD) and the inhibitory effect of nisin on a bacterial strain Micrococcus luteus NCIB 8166 at a range of 0.125-32 IU/ml. The MCA described in this study was very quick. Quantification of nisin took only 7-8 h and the detection limit was at the level of 0.125 IU/ml when compared to 12 IU/ml and 24-28 h for ADA. The MCA provides an accurate and rapid method for quantification of nisin in solutions and is expected to be used for quantification of other antimicrobial substances.
Bacteriocins ; analysis ; metabolism ; Colorimetry ; methods ; Immunodiffusion ; Micrococcus luteus ; metabolism ; Nisin ; Regression Analysis ; Tetrazolium Salts ; analysis ; Thiazoles ; analysis ; Time Factors

BACKGROUNDEarly embryonic developmental arrest is the most commonly understudied adverse outcome of pregnancy. The relevance of intrauterine infection to spontaneous embryonic death is rarely studied and remains unclear. This study aimed to investigate the relationship between intrauterine bacterial infection and early embryonic developmental arrest.

METHODSEmbryonic chorion tissue and uterine swabs for bacterial detection were obtained from 33 patients who underwent artificial abortion (control group) and from 45 patients who displayed early embryonic developmental arrest (trial group).

RESULTSIntrauterine bacterial infection was discovered in both groups. The infection rate was 24.44% (11/45) in the early embryonic developmental arrest group and 9.09% (3/33) in the artificial abortion group. Classification analysis revealed that the highest detection rate for Micrococcus luteus in the early embryonic developmental arrest group was 13.33% (6/45), and none was detected in the artificial abortion group. M. luteus infection was significantly different between the groups (P < 0.05 as shown by Fisher's exact test). In addition, no correlation was found between intrauterine bacterial infection and history of early embryonic developmental arrest.

CONCLUSIONSM. luteus infection is related to early embryonic developmental arrest and might be one of its causative factors.

Abortion, Induced ; statistics & numerical data ; Abortion, Spontaneous ; etiology ; microbiology ; Bacterial Infections ; complications ; Female ; Humans ; Micrococcus luteus ; pathogenicity ; Pregnancy ; Uterus ; microbiology

BACKGROUND: Atopic dermatitis (AD) is a chronically relapsing skin disease that is associated with a disturbance of the epidermal barrier function. Changes in the human skin microbiome have been suggested as a risk factor for AD. OBJECTIVE: The aim of this study was to explore the species distribution of microflora on the skin and in the oral cavity of healthy volunteers and patients with AD. METHODS: Samples for culture were obtained from both lesional skin and the oral cavity in 211 patients with AD and from both the normal skin and oral cavity of 24 healthy controls. Species identification was performed with the VITEK 2 system (bioMerieux Inc., Hazelwood, MO, USA). RESULTS: The isolation of Staphylococcus aureus from the skin was statistically more frequent among patients with AD than among healthy controls, while the isolation of Staphylococcus hominis and Micrococcus luteus were statistically more frequent among healthy controls than among patients with AD (p<0.05). In the oral cavity, S. aureus and Candida albicans were found more frequently in patients with AD, but the difference did was not statistically significant. CONCLUSION: This study provides an important insight into the species distribution of microorganisms on human skin and in the oral cavity. Further investigation is required to determine the role of specific microorganisms in the etiology and pathogenicity of AD.
Candida albicans ; Dermatitis, Atopic* ; Healthy Volunteers ; Humans ; Microbiota ; Micrococcus luteus ; Mouth ; Risk Factors ; Skin Diseases ; Skin* ; Staphylococcus aureus ; Staphylococcus hominis ; Virulence

Two trials of external quality assessment for clinical microbiology laboratories were performed in 2009. A total of 16 specimens were distributed. Eight specimens were distributed to 339 laboratories with 322 (95.0%) returns in Trial I, and another eight specimens to 337 laboratories with 327 returns (97.0%) in Trial II. Two slide specimens for mycobacterium stain (AFB) were distributed in both Trial I and II. The acceptable percentages of Gram stain were relatively good for both stainability and morphology. The acceptable percentages of bacterial identification (correct answers to species level) on Sterotrophomonas maltophilia, Staphylococcus aureus, Streptococcus agalactiae, Micrococcus luteus, Vibrio parahemolyticus and Candida glabrata (Trial I) were 94.4%, 98.5%, 92.1%, 62.3%, 92.1% and 71.5%, respectively. The acceptable percentages of bacterial identification on Pseudomonas aeruginosa, Enterococcus faecalis, Candida albicans, Staphylococcus epidermidis, Moraxella catarrhalis and Enterobacter cloacae (Trial II) were 98.5%, 94.1%, 89.2%, 86.2%, 79.6% and 98.5%, respectively. The acceptable percentages for antimicrobial susceptibility tests on S. maltophilia and S. aureus (Trial I), and P. aeruginosa and E. faecalis(Trial II) were relatively good compared to data of the last year, except results using disk method for S. maltophilia. The acceptable percentages for AFB stain in Trial I and II were relatively high. In summary, the acceptable percentages of bacterial stain and identification were relatively good. However, it is still necessary that the quality assurance of the individual laboratories should be improved for antimicrobial susceptibility tests, and the selection of the most appropriate antimicrobial agents to test should be also considered.
Anti-Infective Agents ; Candida albicans ; Candida glabrata ; Enterobacter cloacae ; Enterococcus faecalis ; Korea ; Micrococcus luteus ; Moraxella (Branhamella) catarrhalis ; Mycobacterium ; Pseudomonas aeruginosa ; Staphylococcus aureus ; Staphylococcus epidermidis ; Streptococcus agalactiae ; Vibrio

PURPOSE: It has been reported that deep neck abscesses are recently increasing again. We analyzed pediatric cases with deep neck abscesses during the last several years to contribute to the treatment of the disease. METHODS: The clinical data of 30 children under 16 years of age with deep neck abscess from February 2001 to July 2006 were analysed retrospectively. RESULTS: The mean age was 9 years (2-16 years), and the male/female ratio was 19/11. Abscesses in the peritonsillar space were most common (57%), followed by the retropharyngeal (30%) and parapharyngeal (13%) spaces. Upper respiratory infection in 10 cases (33%), dental infection in four case (14%), cervical lymphadenitis in three case (10%) and sinusitis in two case (6%) contributed to the development of deep neck infections. The frequent symptoms were fever in 16 case (53%), sore throat in 15 case (50%), poor oral intake in 10 (33%), odynophagia in eight (27%), and neck pain in eight (27%). Unilateral tonsillar hypertrophy and displacement in 15 case (50%) were most common. Neck mass in 13 patients (43%), neck stiffness in three (10%) and trismus in three (10%) were also found. Bacteria were isolated in 8 among 10 pus cultures; Streptococcus species 7 and Micrococcus luteus 1. All of those bacteria except Micrococcus luteus were sensitive to penicillin G. Surgical intervention was applied to 12 cases (40%), and the remaining 18 patients (60%) were treated with antibiotics only. There were no differences between the two groups in the duration of admission and antibiotic treatment. No complicated cases were observed. CONCLUSIONS: Peritonsillar abscesses were most frequent. Upper respiratory infection was the most common predisposing factor, followed by dental infection and sinusitis. Symptoms of respiratory tract obstruction were not found. The most common pathogens were Streptococcus species. Deep neck abscesses in children, if diagnosed at the early stage, possibly can be treated by antibiotics only, without surgical intervention.
Abscess* ; Anti-Bacterial Agents ; Bacteria ; Causality ; Child* ; Fever ; Humans ; Hypertrophy ; Lymphadenitis ; Micrococcus luteus ; Neck Pain ; Neck* ; Penicillin G ; Peritonsillar Abscess ; Pharyngitis ; Respiratory System ; Retrospective Studies ; Sinusitis ; Streptococcus ; Suppuration ; Trismus

Three new phenazine-type compounds, named phenazines SA-SC (1-3), together with four new natural products (4-7), were isolated from the fermentation broth of an earwig-associated Streptomyces sp. NA04227. The structures of these compounds were determined by extensive analyses of NMR, high resolution mass spectroscopic data, as well as single-crystal X-ray diffraction measurement. Sequencing and analysis of the genome data allowed us to identify the gene cluster (spz) and propose a biosynthetic pathway for these phenazine-type compounds. Additionally, compounds 1-5 exhibited moderate inhibitory activity against acetylcholinesterase (AChE), and compound 3 showed antimicrobial activities against Micrococcus luteus.
Animals ; Anti-Bacterial Agents ; chemistry ; metabolism ; pharmacology ; Bacterial Proteins ; genetics ; metabolism ; Crystallography, X-Ray ; Insecta ; microbiology ; Magnetic Resonance Spectroscopy ; Microbial Sensitivity Tests ; Micrococcus luteus ; drug effects ; Molecular Structure ; Multigene Family ; Phenazines ; chemistry ; metabolism ; pharmacology ; Streptomyces ; chemistry ; genetics ; metabolism

The bacterial group which we usually consider as resident flora sometimes changes into opportuniistic pathogen which produces oppartunistic infection, so that attention to resident flora remarkably increased. The main topics of bacterioloical problems of skin flora are as follows: (1) selective localization of resident flora, (2) members of resident flora and their changes by age and area, (3) the role of action of resident flora, (4j the problems of Micrococcus, (5) coagulase negative Staphylococci, (6) coagulase positive Staphylococci, (7) the problerns of Propionilbacterium(P) acnes, (8) typing of propionibacteria existing on human skin, (9) antibiotic sensitivities of P. acnes, (10) effect of tetracycline on lipase productivity oi P. acnes.
Coagulase ; Efficiency ; Humans ; Lipase ; Micrococcus ; Skin* ; Tetracycline