• Microbiology and Biotechnology Letters
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• v.24 no.5
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• pp.636-639
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• 1996

To develop new biologically active compounds produced by anaerobes, 677 soil samples were collected and used to isolate 1, 889 anaerobic bacteria. Among the isolates 427 strains were strict anaerobes and the remaining 1, 462 strains were facultative anaerobes. From 427 strictly anaerobic isolates, 88 strains showed antibacterial activities, and 21 strains were selected for the further studies.

• Journal of Photoscience
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• v.9 no.2
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• pp.142-145
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• 2002

A strict anaerobe, Prevotella melaninogenica is highly sensitive to oxidative stress. Oxidative stress such as exposure to oxygen or addition of hydrogen peroxide, increased 8-hydroxydeoxyguanosine (80HdG), a typical of oxidative DNA damage, and decreased the bacterial cell survival rate. We could detect the generation of reactive oxygen species in P. melaninogenica after exposure to oxygen. UVA irradiation also increased 80HdG in the bacterium. On the other hand, such oxidative stress did not increase 80HdG in a facultative anaerobe. These findings suggest that P. melaninogenica is a suitable material to study the biological effects of oxidative stress, to evaluate antioxidants, and to study the effects of oxygen or reactive oxygen species on molecular evolution.

• Restorative Dentistry and Endodontics
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• v.14 no.1
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• pp.85-96
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• 1989

In the Infected root canals, the majority of the isolated bacteria are either strict anaerobes or microaerophilic organisms. Among thease, Black-pigmented Bacteroides species are the most important and have relation with clinical symptoms. The purpose of this study were to investigate on the 7 different types of bacteria which include Black-pigmented Bacteroides - Black--pigmented Bacteroides, Actinobacillus actinomycetemcomitans, Streptococcus, Capnocytophaga, Eiknella corrodens, Fusobacterium, Actinomyces - and the interrelationship between these 7 bacterical species, and to compare Black-pigmented Bacteroides with the clinical symptoms in infected root canals. The canal contents of 15 necrotized teeth with 8 clinical symptoms were sampled and cultured aerobically and anaerobically for growth in 7 selective agar plates for 7 bacterial species. Black-pigmented Bacteroides and Streptococcus subspecies were identified by biochemical tests. The results were as follows; 1. 70.51% of the bacteria isolated were anaerobes and 29.49% were aerobes. 2. B. loescheii, B. intermedius, B. denticola were isolated in 8 cases, Streptococcus was isolated in 8 cases, Fusobacterium was isolated in 6 cases, Actinomyces was isolated in 5 cases and Eiknella corrodens, Actinobacillus actinomycetemcomitans, Capnocytophaga were not isolated. 3. There were mutual inhibition of growth between Black-pigmented Bacteroides and Streptococcus. (P<0.01) But Actinomyces and Fusobacterium showed mutual aids for growth. (P<0.05) 4. Black-Pigmented Bacteroides was found to be related both to sinus tract formation and to apical sensitivity to palpation.(P < 0.05).

• Korean Journal of Microbiology
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• v.23 no.1
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• pp.43-48
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• 1985

Strict anaerobic procedures and anaerobic chamber were employed in order to improve the isolation of obligate anaerobes from oral pyogenic infections. Also different culture media were utilized to maximize bacterial recovery. Two blood media: nalidixic acid Tween blood agar (NATB) and plain blood agar (BA), two non-blood media: nalidixic acid Tween agar (NAT) and Gifu anaerobic medium (GAM) were used and compared for their isolation efficacy. Specimens from seven patients were collected with syringe. After collection, the needle was sealed with sterilixed silicone rubber and brought to labortory. The time spent from specimen collection to its processing in anaerobic chamber usually was 15 min. Identification of isolated bacterial strains was done with the API-20A system. Increase in isolation of anaerobic vacteria was achieved. Obligate anaerobic bacteria isolated were 3.3 strains per specimen. This figure falls within the range of 1.9-4.4 strains per specimen reported in other countries. With respect to the media utilized, blood media were superior to non-blood media. NATB medium was effective especially for the isolation of Gram-positive cocci. A total of 15 species of Gram-negative rods was isolated and 12 of them belonged to Bacteroides.

• Journal of Soil and Groundwater Environment
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• v.25 no.1
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• pp.25-36
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• 2020

In a redox transition zone, geochemical reactions are facilitated by active bacteria that mediate reactions involving electrons, and arsenic (As) and iron (Fe) cycles are the major electron transfer reactions occurring at such a site. In this study, the effect of repetitive redox changes on soil bacterial community in As-contaminated soil was investigated. The results revealed that bacterial community changed actively in response to redox changes, and bacterial diversity gradually decreased as the cycle repeated. Proportion of strict aerobes and anaerobes decreased, while microaerophilic species such as Azospirillum oryzae group became the predominant species, accounting for 72.7% of the total counts after four weeks of incubation. Bacterial species capable of reducing Fe or As (e.g., Clostridium, Desulfitobacterium) belonging to diverse phylogenetic groups were detected. Indices representing richness (i.e., Chao 1) and phylogenetic diversity decreased from 1,868 and 1,926 to 848 and 1,121, respectively. Principle component analysis suggests that repetitive redox fluctuation, rather than oxic or anoxic status itself, is an important factor in determining the change of soil bacterial community, which in turn affects the cycling of As and Fe in redox transition zones.

• Biomedical Science Letters
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• v.20 no.2
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• pp.77-84
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• 2014

Periodic analysis of local epidemiologic data of prevalent pathogens of blood culture can provide clinicians with relevant information to guide empirical antibiotic therapy. In this study, we analyzed a pattern of change of causative microorganisms and antimicrobial resistance at a tertiary medical center in Chungcheong province from 2003 to 2012, retrospectively. Of 70,258 blood specimens cultured, 6,063 (8.6%) were positive. Among the positive isolates, 95.9% were aerobic or facultative anaerobic bacteria, 0.1% were anaerobes, and 3.9% were fungi. Coagulase-negative Staphylococci (CoNS) (32.9%), Escherichia coli (16.7%), Staphylococcus aureus (9.1%), Klebsiella pneumoniae (6.4%), and ${\alpha}$-hemolytic Streptococcus (5.9%) were commonly isolated bacteria, and Candida albicans (1.4%) was the most commonly isolated fungi. Enterococcus faecium progressively increased but Streptococcus pneumoniae, Acinetobacter baumannii and Proteus species gradually decreased over a period of 10 years. The multidrug-resistant microorganisms such as methicillin-resistant S. aureus (MRSA), vancomycin-resistant enterococci (VRE), cefotaxime-resistant E. coli, imipenem-resistant Pseudomonas aeruginosa (IRPA) and imipenem-resistant A. baumannii (IRAB), were significantly increased. Therefore, there is a need for a more strict control of antibiotics and a more updated guideline for the treatment of bloodstream infection.

• Asian-Australasian Journal of Animal Sciences
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• v.23 no.12
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• pp.1657-1667
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• 2010

Direct-fed microbials (DFM) are dietary supplements that inhibit gastrointestinal infection and provide optimally regulated microbial environments in the digestive tract. As the use of antibiotics in ruminant feeds has been banned, DFM have been emphasized as antimicrobial replacements. Microorganisms that are used in DFM for ruminants may be classified as lactic acid producing bacteria (LAB), lactic acid utilizing bacteria (LUB), or other microorganisms including species of Lactobacillus, Bifidobacterium, Enterococcus, Streptococcus, Bacillus and Propionibacterium, strains of Megasphaera elsdenii and Prevotella bryantii and yeast products containing Saccharomyces and Aspergillus. LAB may have beneficial effects in the intestinal tract and rumen. Both LAB and LUB potentially moderate rumen conditions and improve feed efficiency. Yeast DFM may reduce harmful oxygen, prevent excess lactate production, increase feed digestibility, and improve fermentation in the rumen. DFM may also compete with and inhibit the growth of pathogens, stimulate immune function, and modulate microbial balance in the gastrointestinal tract. LAB may regulate the incidence of diarrhea, and improve weight gain and feed efficiency. LUB improved weight gain in calves. DFM has been reported to improve dry matter intake, milk yield, fat corrected milk yield and milk fat content in mature animals. However, contradictory reports about the effects of DFM, dosages, feeding times and frequencies, strains of DFM, and effects on different animal conditions are available. Cultivation and preparation of ready-to-use strict anaerobes as DFM may be cost-prohibitive, and dosing methods, such as drenching, that are required for anaerobic DFM are unlikely to be acceptable as general on-farm practice. Aero-tolerant rumen microorganisms are limited to only few species, although the potential isolation and utilization of aero-tolerant ruminal strains as DFM has been reported. Spore forming bacteria are characterized by convenience of preparation and effectiveness of DFM delivery to target organs and therefore have been proposed as DFM strains. Recent studies have supported the positive effects of DFM on ruminant performance.