Paraphocaeicola brunensis gen. nov., sp. nov., Carrying Two Variants of nimB Resistance Gene from Bacteroides fragilis, and Caecibacteroides pullorum gen. nov., sp. nov., Two Novel Genera Isolated from Chicken Caeca.

Three difficult-to-cultivate, strictly anaerobic strains, AN20T, AN421T, and AN502, were analyzed within a project studying possible probiotics for newly hatched chickens. Phylogenetic analyses showed that strains AN20T, AN421T, and AN502 formed two well-separated phylogenetic lineages in all phylogenetic and phylogenomic trees comprising members of the family Bacteroidaceae. Comparison to reference genomes of type species Bacteroides fragilis NCTC 9343T, Phocaeicola abscessus CCUG 55929T, and Capsularis zoogleoformans ATCC 33285T showed low relatedness based on the calculated genome-to-genome distance and orthologous average nucleotide identity. Analysis of fatty acid profiles showed iso-C15:0, anteiso-C15:0, C16:0, C18:1ω9c, and iso-C17:0 3OH as the major fatty acids for all three strains and additionally C16:0 3OH for AN421T and AN502. A specific combination of respiratory quinones different from related taxa was found in analyzed strains, MK-5 plus MK-11 in strain AN20T and MK-5 plus MK-10 in strains AN421T and AN502. Strains AN421T and AN502 harbor complete CRISPR loci with CRISPR array, type II-C, accompanied by a set of cas genes (cas9, cas1, and cas2) in close proximity. Interestingly, strain AN20T was found to harbor two copies of nimB gene with >95% similarity to nimB of B. fragilis, suggesting a horizontal gene transfer between these taxa. In summary, three isolates characterized in this study represent two novel species, which we proposed to be classified in two novel genera of the family Bacteroidaceae, for which the names Paraphocaeicola brunensis sp. nov. (AN20T = CCM 9041T = DSM 111154T) and Caecibacteroides pullorum sp. nov. (AN421T= CCM 9040T = DSM 111155T) are proposed. IMPORTANCE This study represents follow-up research on three difficult-to-cultivate anaerobic isolates originally isolated within a project focused on strains that are able to stably colonize newly hatched chickens, thus representing possible probiotics. This project is exceptional in that it successfully isolates several miscellaneous strains that required modified and richly supplemented anaerobic media, as information on many gut-colonizing bacteria is based predominantly on metagenomic studies. Superior colonization of newly hatched chickens by Bacteroides spp., Phocaeicola spp., or related taxa can be considered of importance for development of future probiotics. Although different experiments can also be performed with provisionally characterized isolates, precise taxonomical definition is necessary for subsequent broad communication. The aim of this study is therefore to thoroughly characterize these isolates that represent novel genera and precisely determine their taxonomic position among related taxa to facilitate further research and communication involving these strains.

Source Tracking and Global Distribution of the Tigecycline Non-Susceptible tet(X).

The emergence of tet(X) genes has compromised the clinical use of the last-line antibiotic tigecycline. We identified 322 (1.21%) tet(X) positive samples from 12,829 human microbiome samples distributed in four continents (Asia, Europe, North America, and South America) using retrospective data from worldwide. These tet(X) genes were dominated by tet(X2)-like orthologs but we also identified 12 samples carrying novel tet(X) genes, designed tet(X45), tet(X46), and tet(X47), were resistant to tigecycline. The metagenomic analysis indicated these tet(X) genes distributed in anaerobes dominated by Bacteroidaceae (78.89%) of human-gut origin. Two mobile elements ISBf11 and IS4351 were most likely to promote the transmission of these tet(X2)-like orthologs between Bacteroidaceae and Riemerella anatipestifer. tet(X2)-like orthologs was also developed during transmission by mutation to high-level tigecycline resistant genes tet(X45), tet(X46), and tet(X47). Further tracing these tet(X) in single bacterial isolate from public repository indicated tet(X) genes were present as early as 1960s in R. anatipestifer that was the primary tet(X) carrier at early stage (before 2000). The tet(X2) and non-tet(X2) orthologs were primarily distributed in humans and food animals respectively, and non-tet(X2) were dominated by tet(X3) and tet(X4). Genomic comparison indicated these tet(X) genes were likely to be generated during tet(X) transmission between Flavobacteriaceae and E. coli/Acinetobacter spp., and ISCR2 played a key role in the transmission. These results suggest R. anatipestifer was the potential ancestral source of tet(X). In addition, Bacteroidaceae of human-gut origin was an important hidden reservoir and mutational incubator for the mobile tet(X) genes that enabled spread to facultative anaerobes and aerobes. IMPORTANCE The emergence of the tigecycline resistance gene tet(X) has posed a severe threat to public health. However, reports of its origin and distribution in human remain rare. Here, we explore the origin and distribution of tet(X) from large-scale metagenomic data of human-gut origin and public repository. This study revealed the emergency of tet(X) gene in 1960s, which has refreshed a previous standpoint that the earliest presence of tet(X) was in 1980s. The metagenomic analysis from data mining covered the unculturable bacteria, which has overcome the traditional bacteria isolating and purificating technologies, and the analysis indicated that the Bacteroidaceae of human-gut origin was an important hidden reservoir for tet(X) that enabled spread to facultative anaerobes and aerobes. The continuous monitoring of mobile tigecycline resistance determinants from both culturable and unculturable microorganisms is imperative for understanding and tackling the dissemination of tet(X) genes in both the health care and agricultural sectors.

Melatonin attenuates microbiota dysbiosis of jejunum in short-term sleep deprived mice.

Our study demonstrated that sleep deprivation resulted in homeostasis disorder of colon. Our study goes deeper into the positive effects of melatonin on small intestinal microbiota disorder caused by sleep deprivation. We successfully established a multiplatform 72 h sleep deprivation mouse model with or without melatonin supplementation, and analyzed the change of small intestinal microbiota using high-throughput sequencing of the 16S rRNA. We found melatonin supplementation suppressed the decrease of plasma melatonin level in sleep deprivation mice. Meanwhile, melatonin supplementation improved significantly the reduction in OTU numbers and the diversity and richness of jejunal microbiota and the abundance of Bacteroidaeae and Prevotellaceae, as well as an increase in the Firmicutes-to-Bacteroidetes ratio and the content of Moraxellaceae and Aeromonadaceae in the jejunum of sleep deprived-mice. Moreover, melatonin supplementation reversed the change of metabolic pathway in sleep deprived-mice, including metabolism, signal transduction mechanisms and transcription etc, which were related to intestinal health. Furthermore, melatonin supplementation inverted the sleep deprivation-induced a decline of anti-inflammatory cytokines (IL-22) and an increase of the ROS and proinflammatory cytokines (IL-17) in jejunum. These findings suggested that melatonin, similar to a probiotics agent, can reverse sleep deprivation-induced small intestinal microbiota disorder by suppressing oxidative stress and inflammation response.

Cranberry extracts promote growth of Bacteroidaceae and decrease abundance of Enterobacteriaceae in a human gut simulator model.

The opportunistic pathogen Escherichia coli, a common member of the human gut microbiota belonging to the Enterobacteriaceae family, is the causative agent of the majority of urinary tract infections (UTIs). The gut microbiota serves as a reservoir for uropathogenic E. coli where they are shed in feces, colonize the periurethral area, and infect the urinary tract. Currently, front line treatment for UTIs consists of oral antibiotics, but the rise of antibiotic resistance is leading to higher rates of recurrence, and antibiotics cause collateral damage to other members of the gut microbiota. It is commonly believed that incorporation of the American cranberry, Vaccinium macrocarpon, into the diet is useful for reducing recurrence of UTIs. We hypothesized such a benefit might be explained by a prebiotic or antimicrobial effect on the gut microbiota. As such, we tested cranberry extracts and whole cranberry powder on a human gut microbiome-derived community in a gut simulator and found that cranberry components broadly modulate the microbiota by reducing the abundance of Enterobacteriaceae and increasing the abundance of Bacteroidaceae. To identify the specific compounds responsible for this, we tested a panel of compounds isolated from cranberries for activity against E. coli, and found that salicylate exhibited antimicrobial activity against both laboratory E. coli and human UTI E. coli isolates. In a gut simulator, salicylate reduced levels of Enterobacteriaceae and elevated Bacteroidaceae in a dose dependent manner.

Gut Microbiota Interventions With Clostridium butyricum and Norfloxacin Modulate Immune Response in Experimental Autoimmune Encephalomyelitis Mice.

Gut microbiota has been proposed as an important environmental factor which can intervene and modulate central nervous system autoimmunity. Here, we altered the composition of gut flora with Clostridium butyricum and norfloxacin in experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis. We found that appropriate C. butyricum (5.0 × 106 CFU/mL intragastrically daily, staring at weaning period of age) and norfloxacin (5 mg/kg intragastrically daily, 1 week prior to EAE induction) treatment could both ameliorate EAE although there are obvious differences in gut microbiota composition between these two interventions. C. butyricum increased while norfloxacin decreased the abundance and diversity of the gut microbiota in EAE mice, and both of the treatments decreased firmicutes/bacteroidetes ratio. In the genus level, C. butyricum treatment increased the abundance of Prevotella while Akkermansia and Allobaculum increased in norfloxacin treatment. Moreover, both interventions reduced Desulfovibroneceae and Ruminococcus species. Although there was discrepancy in the gut microbiota composition with the two interventions, C. butyricum and norfloxacin treatment both reduced Th17 response and increased Treg response in the gastrointestinal tract and extra-gastrointestinal organ systems in EAE mice. And the reduced activity of p38 mitogen-activated kinase and c-Jun N-terminal kinase signaling in spinal cord could be observed in the two interventions. The results suggested that manipulation of gut microbiota interventions should take factors such as timing, duration, and dosage into consideration. The discrepancy in the gut microbiota composition and the similar protective T cells response of C. butyricum and norfloxacin implies that achieving intestinal microecology balance by promoting and/or inhibiting the gut microbiota contribute to the well-being of immune response in EAE mice.

The Glucoamylase Inhibitor Acarbose Has a Diet-Dependent and Reversible Effect on the Murine Gut Microbiome.

Acarbose is a safe and effective medication for type 2 diabetes that inhibits host glucoamylases to prevent starch digestion in the small intestines and thus decrease postprandial blood glucose levels. This results in an increase in dietary starch in the distal intestine, where it becomes food for the gut bacterial community. Here, we examined the effect of acarbose therapy on the gut community structure in mice fed either a high-starch (HS) or high-fiber diet rich in plant polysaccharides (PP). The fecal microbiota of animals consuming a low dose of acarbose (25 ppm) was not significantly different from that of control animals that did not receive acarbose. However, a high dose of acarbose (400 ppm) with the HS diet resulted in a substantial change to the microbiota structure. Most notably, the HS diet with a high dose of acarbose lead to an expansion of the Bacteroidaceae and Bifidobacteriaceae and a decrease in the Verrucomicrobiaceae (such as Akkermansia muciniphila) and the Bacteroidales S24-7. Once acarbose treatment ceased, the community composition quickly reverted to mirror that of the control group, suggesting that acarbose does not irreversibly alter the gut community. The high dose of acarbose in the PP diet resulted in a distinct community structure with increased representation of Bifidobacteriaceae and Lachnospiraceae Short-chain fatty acids (SCFAs) measured from stool samples were increased, especially butyrate, as a result of acarbose treatment in both diets. These data demonstrate the potential of acarbose to change the gut community structure and increase beneficial SCFA output in a diet-dependent manner.IMPORTANCE The gut microbial community has a profound influence on host physiology in both health and disease. In diabetic individuals, the gut microbiota can affect the course of disease, and some medications for diabetes, including metformin, seem to elicit some of their benefits via an interaction with the microbiota. Here, we report that acarbose, a glucoamylase inhibitor for type 2 diabetes, changes the murine gut bacterial community structure in a reversible and diet-dependent manner. In both high-starch and high-fiber diet backgrounds, acarbose treatment results in increased short-chain fatty acids, particularly butyrate, as measured in stool samples. As we learn more about how human disease is affected by the intestinal bacterial community, the interplay between medications such as acarbose and the diet will become increasingly important to evaluate.

Comparisons of Effects on Intestinal Short-Chain Fatty Acid Concentration after Exposure of Two Glycosidase Inhibitors in Mice.

Acarbose and voglibose are the most widely used diabetes drugs as glycosidase inhibitors. In this study, the use of these two inhibitors significantly increased the content of starch in large intestine, and altered the concentration of short-chain fatty acids (SCFAs) by affecting the intestinal microbiota. However, there are some differences in the intestinal microbiome of the two groups of mice, mainly in bacteria such as Bacteroidaceae bacteroides and Desulfovibrionaceae desulfovibrio. The productions of acetate and propionate in caecum in voglibose group were significantly higher than those in acarbose group and two kinds of glycosidase inhibitors were close in the production of butyrate in caecum. The Tax4Fun analysis based on Kyoto Encyclopedia of Genes and Genomes (KEGG) data indicated that different productions of acetate and propionate between acarbose group and voglibose group may be related to 2-oxoisovalerate dehydrogenase and pyruvate oxidase. In addition, in-vitro experiments suggested that voglibose had less effect on epithelial cells than acarbose after direct stimulation. According to the recent researches of SCFAs produced by intestinal microbiota, our comparative study shown higher concentration of these beneficial fatty acids in the lumen of voglibose-treated mice, which implied a lower level of inflammation.

Comprehensive evaluation of the bactericidal activities of free bile acids in the large intestine of humans and rodents.

In addition to functioning as detergents that aid digestion of dietary lipids in the intestine, some bile acids have been shown to exhibit antimicrobial activity. However, detailed information on the bactericidal activities of the diverse molecular species of bile acid in humans and rodents is largely unknown. Here, we investigated the toxicity of 14 typical human and rodent free bile acids (FBAs) by monitoring intracellular pH, membrane integrity, and viability of a human intestinal bacterium, Bifidobacterium breve Japan Collection of Microorganisms (JCM) 1192T, upon exposure to these FBAs. Of all FBAs evaluated, deoxycholic acid (DCA) and chenodeoxycholic acid displayed the highest toxicities. Nine FBAs common to humans and rodents demonstrated that α-hydroxy-type bile acids are more toxic than their oxo-derivatives and ß-hydroxy-type epimers. In five rodent-specific FBAs, ß-muricholic acid and hyodeoxycholic acid showed comparable toxicities at a level close to DCA. Similar trends were observed for the membrane-damaging effects and bactericidal activities to Blautia coccoides JCM 1395T and Bacteroides thetaiotaomicron DSM 2079T, commonly represented in the human and rodent gut microbiota. These findings will help us to determine the fundamental properties of FBAs and better understand the role of FBAs in the regulation of gut microbiota composition.

High concentrations of single-walled carbon nanotubes lower soil enzyme activity and microbial biomass.

Nanomaterials such as single-walled carbon nanotubes (SWCNTs) may enter the soil environment with unknown consequences resulting from the development of nanotechnology for a variety of applications. We determined the effects of SWCNTs on soil enzyme activity and microbial biomass through a 3-week incubation of urban soils treated with different concentrations of SWCNTs ranging from 0 to 1000 µg g(-1) soil. The activities of cellobiohydrolase, ß-1,4-glucosidase, ß-1,4-xylosidase, ß-1,4-N-acetylglucosaminidase, L-leucine aminopeptidase, and acid phosphatase and microbial biomass were measured in soils treated with powder and suspended forms of SWCNTs. SWCNTs of concentrations at 300-1000 µg g(-1) soil significantly lowered activities of most enzymes and microbial biomass. It is noteworthy that the SWCNTs showed similar effects to that of multi-walled carbon nanotubes (MWCNTs), but at a concentration approximately 5 times lower; we suggest that this is mainly due to the higher surface area of SWCNTs than that of MWCNTs. Indeed, our results show that surface area of CNTs has significant negative relationship with relative enzyme activity and biomass, which suggests that greater microorganism-CNT interactions could increase the negative effect of CNTs on microorganisms. Current work may contribute to the preparation of a regulatory guideline for the release of CNTs to the soil environment.

In vitro antibacterial activity of zinc oxide on a broad range of reference strains of intestinal origin.

Minimal inhibitory concentrations (MIC) and growth behaviour in ZnO supplemented media were determined by the broth micro dilution method against 75 reference strains. No clear clustering according to bacterial group was observed, but 10 of 11 Lactobacillaceae strains showed high zinc resistance (≥520 µg mL(-1)). Enterobacterial strains showed high (6/11) to medium resistance (5/11). The Clostridia and Bacteroidaceae strains exhibited a diverse range of MIC. The results of this study show that zinc resistance of commensal intestinal bacteria cannot be grouped according to their taxonomic origin and therefore, the antibacterial activity of ZnO in the intestine of farm animals cannot be generalized.

Effectiveness of ozone against periodontal pathogenic microorganisms.

Ozone has been proposed as an adjunct antiseptic in periodontitis therapy. The aim of this study was to investigate the antimicrobial effectiveness of gaseous/aqueous ozone, in comparison with that of the established antiseptic chlorhexidine digluconate (CHX), against periodontal microorganisms. Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Tannerella forsythia, and Parvimonas micra in planktonic or biofilm cultures were exposed, for 1 min, to gaseous ozone, aqueous ozone, CHX, or phosphate-buffered saline (control). None of the agents was able to substantially reduce the A. actinomycetemcomitans count in biofilm cultures. In contrast, P. gingivalis, T. forsythia, and P. micra could be eliminated by 2% CHX or by ozone gas at 53 gm(-3) . Significantly greater antimicrobial effects were observed against planktonic cultures than against biofilm-associated bacteria. The rate of killing was influenced by the species of bacteria, and by the type and concentration of agent. There were no significant differences in the effectiveness of aqueous ozone (20 µg ml(-1) ) or gaseous ozone (≥ 4 gm(-3) ) compared with 2% CHX but they were more effective than 0.2% CHX. Therefore, high-concentrated gaseous and aqueous ozone merit further investigation as antiseptics in periodontitis therapy. A safe system for applying gaseous ozone into the periodontal pocket that avoids inhalation still needs to be developed.

Anti-biofilm properties of Satureja hortensis L. essential oil against periodontal pathogens.

Essential oils of several plants are widely used in ethnomedicine for their antimicrobial and anti-inflammatory properties. However, very limited data exist on their use in connection to periodontal diseases. The aim of the present study was to investigate the bacterial growth inhibiting and anti-biofilm effects of Satureja hortensis L. (summer savory), Salvia fruticosa M. (sage), Lavandula stoechas L. (lavender), Myrtus communis L., and Juniperus communis L. (juniper) essential oils. Chemical compositions of the essential oils were analyzed by gas chromatography-mass spectrometry, minimum inhibitor concentrations (MICs) with the agar dilution method, and anti-biofilm effects by the microplate biofilm assay. The toxicity of each essential oil was tested on cultured keratinocytes. Of the 5 essential oils, S. hortensis L. essential oil had the strongest growth inhibition effect. Subinhibitory dose of S. hortensis L. essential oil had anti-biofilm effects only against Prevotella nigrescens. Essential oils did not inhibit keratinocyte viability at the concentrations of 1 and 5 microl/ml, however at the concentration of 5 microl/ml epithelial cells detached from the culture well bottom. The present findings suggest that S. hortensis L. essential oil inhibits the growth of periodontal bacteria in the concentration that is safe on keratinocytes, however, in the subinhibitory concentration its anti-biofilm effect is limited.

Antimicrobial susceptibility of periodontopathogenic bacteria.

OBJECTIVES: The aim of this study was to evaluate the resistance profiles of Aggregatibacter (Actinobacillus) actinomycetemcomitans, Porphyromonas gingivalis and Prevotella intermedia/Prevotella nigrescens and to detect possible changes in antibiotic resistance over the time period of 1991-2005. METHODS: A. actinomycetemcomitans (125 strains), P. gingivalis (152 strains) and P. intermedia/P. nigrescens (326 strains) isolated during the years 1991-2005 were tested for their susceptibility to amoxicillin/clavulanic acid, clindamycin, metronidazole, phenoxymethylpenicillin and tetracycline using the Etest. RESULTS: No antibiotic resistance was detected in P. gingivalis, whereas a few isolates of P. intermedia were not susceptible to clindamycin (0.9%), phenoxymethylpenicillin (13.5%) or tetracycline (12.6%). Amoxicillin/clavulanic acid, tetracycline and metronidazole were the most effective antibiotics against A. actinomycetemcomitans with 0%, 0.8% and 20.8% non-susceptible isolates, respectively. However, 88% of the A. actinomycetemcomitans isolates were non-susceptible to phenoxymethylpenicillin and 88% to clindamycin. When strains isolated in the years 1991-94 were compared with those isolated in the years 2001-04, there was no statistically significant difference in the percentage of A. actinomycetemcomitans strains non-susceptible to clindamycin, metronidazole or phenoxymethylpenicillin, or in the percentage of P. intermedia strains non-susceptible to phenoxymethylpenicillin or tetracycline (P > 0.4 each). CONCLUSIONS: Increasing antibiotic resistances in periodontopathogenic bacteria are not yet a problem in the Northern part of Switzerland.

A clinical study: Melaleuca, Manuka, Calendula and green tea mouth rinse.

A novel mouthrinse (IND 61,164) containing essential oils and extracts from four plant species (Melaleuca alternifolia, Leptospermum scoparium, Calendula officinalis and Camellia sinensis) were tested. This study aimed to evaluate the safety, palatability and preliminary efficacy of the rinse. Fifteen subjects completed the Phase I safety study. Seventeen subjects completed the Phase II randomized placebo-controlled study. Plaque was collected, gingival and plaque indices were recorded (baseline, 6 weeks, and 12 weeks). The relative abundance of two periodontal pathogens (Actinobacillus actinomycetemcomitans, Tanerella forsythensis) was determined utilizing digoxigenin-labeled DNA probes. ANCOVA was used at the p = 0.05 level of significance. Two subjects reported a minor adverse event. One subject withdrew from the study. Several subjects objected to the taste of the test rinse but continued treatment. Differences between gingival index, plaque index or relative abundance of either bacterial species did not reach statistical significance when comparing nine placebo subjects with eight test rinse subjects. Subjects exposed to the test rinse experienced no abnormal oral lesions, altered vital signs, changes in liver, kidney, or bone marrow function. Larger scale studies would be necessary to determine the efficacy and oral health benefits of the test rinse.

Microbiologic response to treatment of bacterial vaginosis with topical clindamycin or metronidazole.

To compare the frequencies, concentrations, and antimicrobial susceptibilities of vaginal microbes isolated from women with bacterial vaginosis (BV) before and after therapy, 119 nonpregnant women aged 18 to 45 with clinical and Gram stain evidence of BV were randomized to receive intravaginal clindamycin or metronidazole. Vaginal swabs were collected at baseline and 7 to 12 days, 35 to 45 days, and 70 to 90 days following therapy for quantitative vaginal culture. For the 99 women completing all four visits, statistical analyses were performed comparing differences in vaginal microflora between the two treatment arms and between visits in the same treatment group. Antimicrobial susceptibility testing using the agar dilution method was performed for anaerobic gram-negative rods. Although both therapies resulted in decreased colonization by Gardnerella vaginalis and Mycoplasma hominis, only metronidazole treatment resulted in a significant decrease in the frequency and concentration of Prevotella bivia and black-pigmented Prevotella species. Of the 865 anaerobic gram-negative rods evaluated for susceptibility, only 3 (0.3%) were resistant to metronidazole, whereas clindamycin resistance increased significantly for P. bivia and black-pigmented anaerobic gram-negative rods persisting following clindamycin therapy. Clindamycin-resistant subpopulations of P. bivia and black-pigmented Prevotella species emerged 7 to 12 days after therapy even among women colonized initially by clindamycin-susceptible strains. These resistant subpopulations persisted at high frequencies (42 to 50%) 70 to 90 days following therapy. The two topical agents for treatment of BV have differing microbiologic effects on the vaginal microflora. The emergence of clindamycin-resistant anaerobic gram-negative rods following therapy is of concern.

In vitro and in vivo antibacterial activities of telithromycin.

BACKGROUND: Telithromycin is one of the ketolides, characterised by a 3-keto group instead of L-cladinose and a C(11)-C(12) carbamate link by an alkyl chain to a pyridinum and imidazolium ring side chain. We evaluated in vitro and in vivo antibacterial activities of telithromycin against gynaecological pathogens. METHODS: In the vitro study, the antibacterial activity of telithromycin against 180 isolates (isolated in the year 2000) of Streptococcus agalactiae (n = 33), Enterococcus faecalis (n = 22), Neisseria gonorrhoeae (n = 30), Peptostreptococcus anaerobius (n = 20), Finegoldia magna (n = 20), Bacteroides fragilis (n = 25) and Prevotella bivia (n = 30) was compared with that of erythromycin A, clarithromycin, azithromycin, ampicillin and levofloxacin. In the in vivo study, the efficacy of telithromycin was evaluated using experimental intra-abdominal abscesses in mice caused by B. fragilis (minimum inhibitory concentration of telithromycin 0.5 mg/l). RESULTS: In the in vitro study, telithromycin inhibited more than 50% of clinical isolates of S. agalactiae, E. faecalis, N. gonorrhoeae, P. anaerobius, F. magna, B. fragilis and P. bivia at concentrations of 0.016, 0.063, 0.063, 0.032, 0.032, 0.5 and 0.25 mg/l, respectively. Telithromycin inhibited more than 90% of these clinical isolates at concentrations of 0.016, 4, 0.125, 0.063, 0.063, 4 and 1 mg/l, respectively. In the in vivo study, telithromycin inhibited abscess formation and significantly decreased viable cell counts in abscesses in comparison with the untreated group. CONCLUSIONS: These in vitro and in vivo antibacterial activities suggest that telithromycin could be a potential candidate for the treatment of bacterial infections complicated by chlamydial infection.

[Comparative antibiotic susceptibility in vitro of microbial isolates from patients with complications after gastrectomy for stomach carcinoma and from contents of their large intestine]. / Sravnitel'naia chuvstvitel'nost' k antibiotikam in vitro mikroorganizmov, vydelennykh u bol'nykh rakom zheludka pri oslozhneniiakh posle gastréktomii i iz soderzhimogo tolstogo kishechnika.

Antibiotic susceptibility of the main isolates from the large intestine contents and pathological substrates of 12 patients after gastroectomy for stomach carcinoma was studied. Three of them developed esophagoenterostomy incompetence, 4 had intraabdominal abscesses and in 5 infection of the operation wound was stated. In all, 30 isolates of enterobacteria, 28 isolates of enterococci and 38 isolates of bacteroides were tested. Antibiotic susceptibility of the isolates from various sources was practically identical, which showed that before surgical operations for stomach carcinoma it was necessary that data on the patients intestine microbiocenosis and antibioticograms of the main isolates should be available to correct severe dysbiotic disorders.

Epitope mapping of monoclonal antibodies specific for the directly cross-linked mesodiaminopimelic acid peptidoglycan found in the anaerobic beer spoilage bacterium Pectinatus cerevisiiphilus.

Nineteen monoclonal antibodies (Mabs) were isolated based on reactivity with disrupted Pectinatus cerevisiiphilus cells. All of the Mabs reacted with cells from which the outer membrane had been stripped by incubation with sodium dodecyl sulphate, suggesting the peptidoglycan (PG) layer was involved in binding. Mab reactivity with purified PG confirmed this. Epitope mapping revealed the Mabs in total recognize four binding sites on the PG. Mabs specific for each of the four sites also bound strongly to disrupted Pectinatus frisingensis, Selenomonas lacticifix, Zymophilus paucivorans, and Zymophilus raffinosivorans cells, but weakly to disrupted Megasphaera cerevisiae cells. No antibody reactivity was seen with disrupted cells of 11 other species of Gram-negative bacteria. These results confirm that a common PG structure is used by several species of anaerobic Gram-negative beer spoilage bacteria. These results also indicate that PG-specific Mabs can be used to rapidly detect a range of anaerobic Gram-negative beer spoilage bacteria, provided the bacterial outer membrane is first removed to allow antibody binding.

Prevalence of nim genes in anaerobic/facultative anaerobic bacteria isolated in South Africa.

This study investigated the prevalence of nim genes (proposed to encode a 5-nitroimidazole resistance product) in 64 anaerobic/facultative anaerobic bacteria. Employing universal nim gene primers, 458-bp amplified fragments were recorded as presumptive positives in 22/64 strains at an annealing temperature of 52 degrees C and 15/64 strains at 62 degrees C, of which seven were propionibacteria. DNA sequencing confirmed the presence of nimA genes in Propionibacterium spp. (five strains), Actinomyces odontolyticus (one strain), Prevotella bivia (one strain) and Clostridium bifermentans (one strain) and nimB genes from five strains of Bacteroides fragilis. nimA genes were predominant in propionibacteria indicating a potential nimA gene source in anaerobic environments.

Survey of anaerobic susceptibility patterns: a French multicentre study.

In 1996, the in vitro antibiotic susceptibility of 463 anaerobes was measured in five hospitals using the reference agar dilution method. None of the 209 B. fragilis group strains showed resistance to imipenem or ticarcillin-clavulanic acid. High resistance rates (29%) were observed for cefotetan and clindamycin. beta-Lactamase production was detected respectively in 64% of the Prevotella and 7% of the Fusobacterium strains. Because the same standardized methods were used for many years, the authors were able to evaluate the evolution of antibiotic resistance. Clindamycin resistance had increased within the B. fragilis group (from 14% in 1992 to 29% in 1996) and also among strains of clostridia (32%), P. acnes (18%) and Peptostreptococcus (28%). In the B. fragilis group multidrug resistance was unlikely to occur.