Transmission mode and dispersal traits correlate with host specificity in mammalian gut microbes.

Different host species associate with distinct gut microbes in mammals, a pattern sometimes referred to as phylosymbiosis. However, the processes shaping this host specificity are not well understood. One model proposes that barriers to microbial transmission promote specificity by limiting microbial dispersal between hosts. This model predicts that specificity levels measured across microbes is correlated to transmission mode (vertical vs. horizontal) and individual dispersal traits. Here, we leverage two large publicly available gut microbiota data sets (1490 samples from 195 host species) to test this prediction. We found that host specificity varies widely across bacteria (i.e., there are generalist and specialist bacteria) and depends on transmission mode and dispersal ability. Horizontally-like transmitted bacteria equipped with traits that facilitate switches between host (e.g., tolerance to oxygen) were found to be less specific (more generalist) than microbes without those traits, for example, vertically-like inherited bacteria that are intolerant to oxygen. Altogether, our findings are compatible with a model in which limited microbial dispersal abilities foster host specificity.

Chryseobacterium luquanense sp. nov., a casein-hydrolysing bacterium from the Jiaozi Mountain in Yunnan, PR China.

Strain KC 927T was isolated during an investigation of the soil bacteria diversity on Jiaozi Mountain, central Yunnan, Southwest China. The strain was Gram-stain-negative, rod-shaped, non-motile, oxidase-negative, catalase-positive and aerobic. Results of 16S rRNA gene alignment and phylogenetic analysis indicated that strain KC 927T was a member of the genus Chryseobacterium and closely related to Chryseobacterium caseinilyticum GCR10T (98.4%), Chryseobacterium piscicola DSM 21068T (98.3 %) and 'Chryseobacterium formosus' CCTCC AB 2015118T (97.9 %). With a genome size of 4 348 708 bp, strain KC 927T had 33.5 mol% DNA G+C content and contained 4012 protein-coding genes and 77 RNA genes. The average nucleotide identity and digital DNA-DNA hybridization values between strain KC 927T and C. caseinilyticum GCR10T, C. piscicola DSM 21068T and 'C. formosus' CCTCC AB 2015118T were 80.1, 79.6 and 90.7 %, and 25.5, 23.6 and 42.0 %, respectively. The main polar lipid of strain KC 927T was phosphatidylethanolamine and the respiratory quinone was MK-6. The major fatty acids (≥10 %) were iso-C15 : 0, iso-C17 : 1 ω9c and iso-C17 : 0 3-OH. Evidence from phenotypic, phylogenetic and chemotaxonomic analyses support that strain KC 927T represents a new species of the genus Chryseobacterium, for which the name Chryseobacterium luquanense sp. nov. is proposed. The type strain is KC 927T (=CGMCC 1.18760T=JCM 35707T).

Detection of aerobe-anaerobe mixed infection by metagenomic next-generation sequencing in an adult suffering from descending necrotizing mediastinitis.

BACKGROUND: Descending necrotizing mediastinitis (DNM) is one of the most virulent forms of mediastinitis. The main causes of high mortality in DNM are believed to stem from difficulty and delay in the diagnosis. Fast and accurate identification of pathogens is important for the treatment of these patients. Metagenomics next-generation sequencing (mNGS) is a powerful tool to identify all kinds of pathogens, especially for rare and complex infections. CASE PRESENTATION: A 64-year-old male patient was admitted to the intensive care unit (ICU) with unconsciousness, dyspnea, and swelling in the mandible and neck. Computed tomography (CT) scan results combined with clinical laboratory examination indicated DNM. Vancomycin and imipenem were used, and vacuum sealing drainage was applied for debridement and drainage of the infected area. The positive mNGS results of drainage fluid confirmed the presence of mixed infection caused by Streptococcus anginosus, Prevotella oris, and several other anaerobes. The antibiotics were adjusted to piperacillin/tazobactam and tinidazole according to the mNGS results and antimicrobial susceptibility testing of cultured pathogens. After 11 days of antibiotic therapy, the infection symptoms of the neck and mediastinum improved, and the patient was transferred out of the ICU on the 26th day after negative result of drainage fluid culture. CONCLUSION: This case suggested that mNGS is a promising technology for precise and fast pathogens identification with high sensitivity, which may guide the diagnosis of infectious diseases in the future trend.

Oxygen concentration affects frequency and range of transconjugants for the incompatibility (Inc) P-1 and P-7 plasmids pBP136 and pCAR1.

The frequency of transconjugants were compared for the incompatibility (Inc) P-1 and P-7 plasmids pBP136 and pCAR1 under aerobic and anaerobic conditions. Filter mating assays were performed with one donor strain and one recipient strain using different donors of Pseudomonas and recipient strains, including Pseudomonas, Pantoea, and Buttiauxella. Under anaerobic condition, frequencies of transconjugants for both plasmids were 101-103-fold lower than those under aerobic condition regardless of whether aerobically or anaerobically grown donors and recipients were used. To compare the transconjugant ranges under aerobic and anaerobic conditions, conjugation was performed between the donor of pBP136 and recipient bacteria extracted from environmental samples. Several transconjugants were uniquely obtained from each aerobic or anaerobic condition. Our findings indicate that a plasmid can differently spread among bacteria depending on the oxygen concentrations of the environment.

Protective Role of Bacterial Alkanesulfonate Monooxygenase under Oxidative Stress.

Bacterial alkane metabolism is associated with a number of cellular stresses, including membrane stress and oxidative stress, and the limited uptake of charged ions such as sulfate. In the present study, the genes ssuD and tauD in Acinetobacter oleivorans DR1 cells, which encode an alkanesulfonate monooxygenase and a taurine dioxygenase, respectively, were found to be responsible for hexadecanesulfonate (C16SO3H) and taurine metabolism, and Cbl was experimentally identified as a potential regulator of ssuD and tauD expression. The expression of ssuD and tauD occurred under sulfate-limited conditions generated during n-hexadecane degradation. Interestingly, expression analysis and knockout experiments suggested that both genes are required to protect cells against oxidative stress, including that generated by n-hexadecane degradation and H2O2 exposure. Measurable levels of intracellular hexadecanesulfonate were also produced during n-hexadecane degradation. Phylogenetic analysis suggested that ssuD and tauD are mainly present in soil-dwelling aerobes within the Betaproteobacteria and Gammaproteobacteria classes, which suggests that they function as controllers of the sulfur cycle and play a protective role against oxidative stress in sulfur-limited conditions.IMPORTANCEssuD and tauD, which play a role in the degradation of organosulfonate, were expressed during n-hexadecane metabolism and oxidative stress conditions in A. oleivorans DR1. Our study confirmed that hexadecanesulfonate was accidentally generated during bacterial n-hexadecane degradation in sulfate-limited conditions. Removal of this by-product by SsuD and TauD must be necessary for bacterial survival under oxidative stress generated during n-hexadecane degradation.

Aerobic prokaryotes do not have higher GC contents than anaerobic prokaryotes, but obligate aerobic prokaryotes have.

BACKGROUND: Among the four bases, guanine is the most susceptible to damage from oxidative stress. Replication of DNA containing damaged guanines results in G to T mutations. Therefore, the mutations resulting from oxidative DNA damage are generally expected to predominantly consist of G to T (and C to A when the damaged guanine is not in the reference strand) and result in decreased GC content. However, the opposite pattern was reported 16 years ago in a study of prokaryotic genomes. Although that result has been widely cited and confirmed by nine later studies with similar methods, the omission of the effect of shared ancestry requires a re-examination of the reliability of the results. RESULTS: When aerobic and obligate aerobic prokaryotes were mixed together and anaerobic and obligate anaerobic prokaryotes were mixed together, phylogenetic controlled analyses did not detect significant difference in GC content between aerobic and anaerobic prokaryotes. This result is consistent with two generally neglected studied that had accounted for the phylogenetic relationship. However, when obligate aerobic prokaryotes were compared with aerobic prokaryotes, anaerobic prokaryotes, and obligate anaerobic prokaryotes separately using phylogenetic regression analysis, a significant positive association was observed between aerobiosis and GC content, no matter it was calculated from whole genome sequences or the 4-fold degenerate sites of protein-coding genes. Obligate aerobes have significantly higher GC content than aerobes, anaerobes, and obligate anaerobes. CONCLUSIONS: The positive association between aerobiosis and GC content could be attributed to a mutational force resulting from incorporation of damaged deoxyguanosine during DNA replication rather than oxidation of the guanine nucleotides within DNA sequences. Our results indicate a grade in the aerobiosis-associated mutational force, strong in obligate aerobes, moderate in aerobes, weak in anaerobes and obligate anaerobes.

Gene-targeted microfluidic cultivation validated by isolation of a gut bacterium listed in Human Microbiome Project's Most Wanted taxa.

This paper describes a microfluidics-based workflow for genetically targeted isolation and cultivation of microorganisms from complex clinical samples. Data sets from high-throughput sequencing suggest the existence of previously unidentified bacterial taxa and functional genes with high biomedical importance. Obtaining isolates of these targets, preferably in pure cultures, is crucial for advancing understanding of microbial genetics and physiology and enabling physical access to microbes for further applications. However, the majority of microbes have not been cultured, due in part to the difficulties of both identifying proper growth conditions and characterizing and isolating each species. We describe a method that enables genetically targeted cultivation of microorganisms through a combination of microfluidics and on- and off-chip assays. This method involves (i) identification of cultivation conditions for microbes using growth substrates available only in small quantities as well as the correction of sampling bias using a "chip wash" technique; and (ii) performing on-chip genetic assays while also preserving live bacterial cells for subsequent scale-up cultivation of desired microbes, by applying recently developed technology to create arrays of individually addressable replica microbial cultures. We validated this targeted approach by cultivating a bacterium, here referred to as isolate microfluidicus 1, from a human cecal biopsy. Isolate microfluidicus 1 is, to our knowledge, the first successful example of targeted cultivation of a microorganism from the high-priority group of the Human Microbiome Project's "Most Wanted" list, and, to our knowledge, the first cultured representative of a previously unidentified genus of the Ruminococcaceae family.

Reduction of selenite to Se(0) nanoparticles by filamentous bacterium Streptomyces sp. ES2-5 isolated from a selenium mining soil.

BACKGROUND: Selenium (Se) is an essential trace element in living systems. Microorganisms play a pivotal role in the selenium cycle both in life and in environment. Different bacterial strains are able to reduce Se(IV) (selenite) and (or) Se(VI) (selenate) to less toxic Se(0) with the formation of Se nanoparticles (SeNPs). The biogenic SeNPs have exhibited promising application prospects in medicine, biosensors and environmental remediation. These microorganisms might be explored as potential biofactories for synthesis of metal(loid) nanoparticles. RESULTS: A strictly aerobic, branched actinomycete strain, ES2-5, was isolated from a selenium mining soil in southwest China, identified as Streptomyces sp. based on 16S rRNA gene sequence, physiologic and morphologic characteristics. Both SEM and TEM-EDX analysis showed that Se(IV) was reduced to Se(0) with the formation of SeNPs as a linear chain in the cytoplasm. The sizes of the SeNPs were in the range of 50-500 nm. The cellular concentration of glutathione per biomass decreased along with Se(IV) reduction, and no SeNPs were observed in different sub-cellular fractions in presence of NADPH or NADH as an electron donor, indicating glutathione is most possibly involved in vivo Se(IV) reduction. Strain ES2-5 was resistant to some heavy metal(loid)s such as Se(IV), Cr(VI) and Zn(II) with minimal inhibitory concentration of 50, 80 and 1.5 mM, respectively. CONCLUSIONS: The reducing mechanism of Se(IV) to elemental SeNPs under aerobic condition was investigated in a filamentous strain of Streptomyces. Se(IV) reduction is mediated by glutathione and then SeNPs synthesis happens inside of the cells. The SeNPs are released via hypha lysis or fragmentation. It would be very useful in Se bioremediation if Streptomyces sp. ES2-5 is applied to the contaminated site because of its ability of spore reproduction, Se(IV) reduction, and adaptation in soil.

Protons and pleomorphs: aerobic hydrogen production in Azotobacters.

As obligate aerobic soil organisms, the ability of Azotobacter species to fix nitrogen is unusual given that the nitrogenase complex requires a reduced cellular environment. Molecular hydrogen is an unavoidable byproduct of the reduction of dinitrogen; at least one molecule of H2 is produced for each molecule of N2 fixed. This could be considered a fault in nitrogenase efficiency, essentially a waste of energy and reducing equivalents. Wild-type Azotobacter captures this hydrogen and oxidizes it with its membrane-bound uptake hydrogenase complex. Strains lacking an active hydrogenase complex have been investigated for their hydrogen production capacities. What is the role of H2 in the energy metabolism of nitrogen-fixing Azotobacter? Is hydrogen production involved in Azotobacter species' protection from or tolerance to oxygen, or vice versa? What yields of hydrogen can be expected from hydrogen-evolving strains? Can the yield of hydrogen be controlled or increased by changing genetic, environmental, or physiological conditions? We will address these questions in the following mini-review.

ATP binding by an F1Fo ATP synthase ε subunit is pH dependent, suggesting a diversity of ε subunit functional regulation in bacteria.

It is a conjecture that the ε subunit regulates ATP hydrolytic function of the F1Fo ATP synthase in bacteria. This has been proposed by the ε subunit taking an extended conformation, with a terminal helix probing into the central architecture of the hexameric catalytic domain, preventing ATP hydrolysis. The ε subunit takes a contracted conformation when bound to ATP, thus would not interfere with catalysis. A recent crystallographic study has disputed this; the Caldalkalibacillus thermarum TA2.A1 F1Fo ATP synthase cannot natively hydrolyse ATP, yet studies have demonstrated that the loss of the ε subunit terminal helix results in an ATP synthase capable of ATP hydrolysis, supporting ε subunit function. Analysis of sequence and crystallographic data of the C. thermarum F1Fo ATP synthase revealed two unique histidine residues. Molecular dynamics simulations suggested that the protonation state of these residues may influence ATP binding site stability. Yet these residues lie outside the ATP/Mg2+ binding site of the ε subunit. We then probed the effect of pH on the ATP binding affinity of the ε subunit from the C. thermarum F1Fo ATP synthase at various physiologically relevant pH values. We show that binding affinity changes 5.9 fold between pH 7.0, where binding is weakest, to pH 8.5 where it is strongest. Since the C. thermarum cytoplasm is pH 8.0 when it grows optimally, this correlates to the ε subunit being down due to ATP/Mg2+ affinity, and not being involved in blocking ATP hydrolysis. Here, we have experimentally correlated that the pH of the bacterial cytoplasm is of critical importance for ε subunit ATP affinity regulated by second-shell residues thus the function of the ε subunit changes with growth conditions.

Obligately aerobic human gut microbe expresses an oxygen resistant tungsten-containing oxidoreductase for detoxifying gut aldehydes.

Brevibacillus massiliensis strain phR is an obligately aerobic microbe that was isolated from human feces. Here, we show that it readily takes up tungsten (W), a metal previously associated only with anaerobes. The W is incorporated into an oxidoreductase enzyme (BmWOR) that was purified from native biomass. BmWOR consists of a single 65 kDa subunit and contains a single W-pyranopterin cofactor and a single [4Fe-4S] cluster. It exhibited high aldehyde-oxidizing activity with very high affinities (apparent Km < 6 µM) for aldehydes common in the human gut and in cooked foods, including furfural, propionaldehyde, benzaldehyde and tolualdehyde, suggesting that BmWOR plays a key role in their detoxification. B. massiliensis converted added furfural to furoic acid when grown in the presence of W, but not in the presence of the analogous element molybdenum. B. massiliensis ferredoxin (BmFd) served as the electron acceptor (apparent Km < 5 µM) for BmWOR suggesting it is the physiological electron carrier. Genome analysis revealed a Fd-dependent rather than NADH-dependent Complex I, suggesting that WOR not only serves a detoxification role but its aldehyde substrates could also serve as a source of energy. BmWOR is the first tungstoenzyme and the first member of the WOR family to be obtained from a strictly aerobic microorganism. Remarkably, BmWOR oxidized furfural in the presence of air (21% O2, v/v) but only if BmFd was also present. BmWOR is the first characterized member of the Clade 83 WORs, which are predominantly found in extremely halophilic and aerobic archaea (Clade 83A), with many isolated from food sources, while the remaining bacterial members (Clade 83B) include both aerobes and anaerobes. The potential advantages for microbes found in foods and involved in human gut health that harbor O2-resistant WORs, including in Bacillus and Brevibacillus based-probiotics, are discussed.

Peritonsillar abscess: an 8-year retrospective, culture based evaluation of 208 cases.

Introduction. Peritonsillar abscess (PTA) is a common infection which requires surgical intervention and suitable antibiotic therapy.Hypotheses/Gap Statement. Beside Streptococcus pyogenes and Fusobacterium necrophorum several other mostly anaerobic bacteria can be cultured from the properly taken pus samples of PTA, the clinical significance of which is still not fully understood.Aim. This study focused on the culture-based microbiological evaluation of PTA cases, compared to surgical intervention and empirical antibiotic management.Methodology. A retrospective analysis of PTA cases was performed between 2012 and 2019. Data about the aerobic and anaerobic culture results of the samples taken during different surgical interventions were summarized and the coverage of the empirically selected antibiotics was evaluated. The patient's history, the development of complications and the recurrence rate were also evaluated.Results. The microbiological culture results were available for 208 of 320 patients with clinically diagnosed PTA. Incision and drainage (I and D) and immediate tonsillectomy were the leading surgical interventions. Ninety-five Fusobacterium species (including 44 Fusobacterium necrophorum), 52 Actinomyces species and 47 Streptococcus pyogenes were obtained from PTA samples alone or together with polymicrobial flora. S. pyogenes (33.7 %, n=28) and F. necrophorum (22.9 %, n=19) were the dominating pathogens in the 83 monobacterial PTA samples. In >60 % of the patients polymicrobial infection was demonstrated, involving a great variety of anaerobic bacteria. In 22 out of 42 cases where intravenous cefuroxime was empirically started, the therapy should be changed to properly cover the culture-proven anaerobic flora. There were no serious complications, abscess recurrence was detected in two cases (0.96 %).Conclusion. PTAs are often polymicrobial infections including a great variety of anaerobes. Targeted antibiotic therapy, in conjunction with adequate surgical drainage eliminating the anaerobic milieu, can accelerate the healing process and radically reduce the complication and recurrence rate.

A PAS Protein Directs Metabolic Reprogramming during Cryptococcal Adaptation to Hypoxia.

To aerobic organisms, low oxygen tension (hypoxia) presents a physiological challenge. To cope with such a challenge, metabolic pathways such as those used in energy production have to be adjusted. Many of such metabolic changes are orchestrated by the conserved hypoxia-inducible factors (HIFs) in higher eukaryotes. However, there are no HIF homologs in fungi or protists, and not much is known about conductors that direct hypoxic adaptation in lower eukaryotes. Here, we discovered that the transcription factor Pas2 controls the transcript levels of metabolic genes and consequently rewires metabolism for hypoxia adaptation in the human fungal pathogen Cryptococcus neoformans Through genetic, proteomic, and biochemical analyses, we demonstrated that Pas2 directly interacts with another transcription factor, Rds2, in regulating cryptococcal hypoxic adaptation. The Pas2/Rds2 complex represents the key transcription regulator of metabolic flexibility. Its regulation of metabolism rewiring between respiration and fermentation is critical to our understanding of the cryptococcal response to low levels of oxygen.IMPORTANCEC. neoformans is the main causative agent of fungal meningitis that is responsible for about 15% of all HIV-related deaths. Although an obligate aerobic fungus, C. neoformans is well adapted to hypoxia conditions that the fungus could encounter in the host or the environment. The sterol regulatory element binding protein (SREBP) is well known for its role in cryptococcal adaptation to hypoxia through its regulation of ergosterol and lipid biosynthesis. The regulation of metabolic reprogramming under hypoxia, however, is largely unknown. Here, we discovered one key regulator, Pas2, that mediates the metabolic response to hypoxia together with another transcription factor, Rds2, in C. neoformans The findings help define the molecular mechanisms underpinning hypoxia adaptation in this and other lower eukaryotes.

Probiotic mixtures with aerobic constituent promoted the recovery of multi-barriers in DSS-induced chronic colitis.

AIMS: Gut microbiota has been closely linked to the mucosal immune and been regarded as a reliable target for intestinal inflammation. This study aimed to explore the therapeutic roles of probiotic mixtures of Bifidobacterium infantis, Lactobacillus acidophilus, Enterococcus faecalis with (quadruple probiotics, P-qua) or without (triple probiotics, P-tri) aerobic Bacillus cereus in colitis, focusing on the multiple barrier functions. MATERIALS AND METHODS: Chronic colitis was induced by dextran sulfate sodium (DSS) in C57BL/6 mice. The probiotic mixtures P-qua or P-tri was gavage administrated respectively, while fecal microbiota transplantation (FMT) as a positive control. The intestinal inflammation and functions of multiple barriers were assessed, including the mucus barrier, epithelial barrier and endothelial barrier known as gut-vascular barrier (GVB). Altered composition and diversity in gut microbiota were observed via sequencing analysis. KEY FINDINGS: Both P-qua and P-tri relieved the intestinal inflammation and improved the functions of multiple barriers with increased integrity of mucous layer, enhanced transepithelial electrical resistance, declined epithelial and endothelial permeability to macromolecules in DSS-colitis. Aerobe-contained P-qua revealed a more active role in barrier recovering relative to P-tri, while FMT as a positive control seemed to get better results than pure probiotics. Indeed, P-qua was effective in rebuilding the structure and diversity of gut flora in DSS-colitis, especially increased abundance of Bifidobacterium, Akkermansia, Lactobacillus and Bacteroides. SIGNIFICANCE: Aerobe-contained P-qua was a powerful adjuvant therapy for chronic colitis, via restoring the intestinal microflora and recovering the multi-barriers in the inflamed gut.

The role of microbiological examination in treating peritonsillar abscess based on the retrospective analysis of data from six years / A mikrobiológiai vizsgálatok szerepe a peritonsillaris tályog kezelésében hat év anyagának retrospektív elemzése alapján.

Összefoglaló. Bevezetés és célkituzés: A peritonsillaris tályog a leggyakoribb mély nyaki infekció. Olyan fül-orr-gégészeti kórkép, amely megfelelo kezelés nélkül életveszélyes szövodményekkel járhat. Dönto jelentoségu az empirikus antibiotikumválasztás, melyhez ismerni kell a leggyakoribb kórokozókat és a várható rezisztenciát. Módszerek: A 2012 és 2017 között peritonsillaris tályog miatt kezelt esetek retrospektív feldolgozását végeztük. Összesítettük a sebészi beavatkozás során vett minták aerob és anaerob irányú tenyésztési eredményeit, valamint az empirikusan választott antibiotikumokat. A rutinszeru mikrobiológiai tenyésztés alapján meghatároztuk a leggyakoribb kórokozókat. Az adatokat nemzetközi felmérések eredményeivel hasonlítottuk össze. Eredmények: A vizsgált 6 év során 217 esetben kezeltünk peritonsillaris tályogos beteget. A tenyésztési eredményeket csak 146 esetben tudtuk elemezni. Ebbol 47 esetben került sor Fusobacterium species (ebbol 25 esetben Fusobacterium necrophorum), 31 esetben Actinomyces species és 29 esetben Streptococcus pyogenes izolálására. Az esetek kétharmadában vegyes aerob/anaerob baktériumflórát izolált a laboratórium. Következtetés: A tályogok kezelésében önmagában a sebészi beavatkozás - az anaerob környezet megszüntetésével - jelentos klinikai javulást eredményez. A jól választott antibiotikum meggyorsíthatja a lefolyást, és csökkentheti az esetleges szövodményeket. Nagy jelentosége van a megfelelo mikrobiológiai mintavételnek, nem vagy nehezen gyógyuló esetekben ez teremtheti meg a célzott antibiotikumterápiára történo váltás lehetoségét. Felmérésünk alapján a peritonsillaris tályogok jelentos részét vegyes baktériumflóra okozza, így a szájüregi anaerob baktériumokra is ható amoxicillin-klavulánsav vagy antibiotikum kombinációjának (2. vagy 3. generációs cefalosporinok kombinálva klindamicinnel vagy metronidazollal) alkalmazása javasolt mint empirikus antibiotikumterápia. Orv Hetil. 2020; 161(44): 1877-1883. INTRODUCTION AND OBJECTIVE: Peritonsillar abscess is the most common deep neck infection. Without adequate treatment, this otolaryngological disease pattern can cause life-threatening complications. The empirical choice of antibiotics is crucial which requires knowledge of the most common pathogens and the potential resistance. METHODS: A retrospective analysis of cases treated for peritonsillar abscess was performed between 2012 and 2017. We summarized the aerobic and anaerobic culture results of the surgical samples and the empirically selected antibiotics. The most common pathogens were determined via routine microbiological culture tests. We compared our data with the results of international studies. RESULTS: During the 6-year study at our Clinic, 217 patients with peritonsillar abscess were treated. The microbiological tests were available for analysis in only 146 cases. In 47 cases, Fusobacterium species (including 25 cases with Fusobacterium necrophorum), in 31 cases Actinomyces species and in 29 cases Streptococcus pyogenes were isolated. In 2/3 of the patients, polymicrobial infection was detected. CONCLUSION: In the treatment of peritonsillar abscesses, surgical intervention can result in clinical improvement because of the elimination of the anaerobic milieu. A well-chosen antibiotic can accelerate the healing process and reduce the complication rate. Proper microbiological sampling is of great importance, and in cases of non-recovery or poor recovery, this may create the opportunity to switch for targeted antibiotic therapy. The results of this study show that polymicrobial flora is very important for the development of the peritonsillar abscess, thus the recommended antibiotic therapy is amoxicillin-clavulanic acid or 2nd/3rd generation cefalosporin combined with metronidazol or clindamycin. Orv Hetil. 2020; 161(44): 1877-1883.

Bacterial contamination in cutaneous leishmaniasis: its effect on the lesions' healing course.

BACKGROUND: The colonization of aerobic and anaerobic microbial agents on cutaneous leishmaniasis (CL) lesions, especially acute erosive ulcerative ones, has been mentioned in previous studies showing controversial results on the healing course of lesions with the use of antibiotics. AIMS: The purpose of this study was to evaluate the prevalence of secondary bacterial infections in CL lesions and the effect of its elimination on the lesions' improvement rate. MATERIALS AND METHODS: This cross-sectional clinical trial was performed on 84 acute CL patients. The required skin samples were taken. Cultivation for bacteria was conducted. Patients with positive culture results were divided into two groups. Both groups received standard anti-leishmania treatment, whereas only one group was treated with cephalexin 40-50 mg/kg/day for 10 days. The improvement rate was evaluated in the following visits based on changes in the lesions' induration size. RESULTS: Among the 84 studied patients, 22.6% had a negative culture result whereas the result was positive in 77.4%. The most common pathogenic germs were Staphylococcus aureus (52.3%) and Staphylococcus epidermidis (9.5%); 34/5% of the positive lesions received antibiotic treatment. Finally, among the lesions with a 75-100% improvement rate, no significant difference was observed between the antibiotic-treated and -untreated groups (36.1% vs. 63.9%, respectively, P = 0.403). CONCLUSIONS: The most common pathogen was S. aureus and, as a primary outcome, the simultaneous treatment for microbial agents did not have any considerable effect on the improvement rate of CL lesions.

Microbial flora in chronic periodontitis: study at a tertiary health care center from north karnataka.

BACKGROUND AND OBJECTIVE: Periodontitis is a major public health problem in India with a prevalence of 60-80%. If untreated it acts as a risk factor for systemic diseases. Data on anaerobic periodontal microflora in the Indian population is very scarce. Hence, this study was undertaken to know the nature of oral microbiota in chronic periodontitis in this region of India and also the semiquantitative study in pre- and post-treatment group and to determine antibiotic susceptibility pattern for aerobic isolates. MATERIALS AND METHODS: The present study was conducted on 60 cases. Material was collected from the subgingival pockets in patients with chronic periodontitis attending the Periodontology, Outpatient Department. Clinical samples were transported to the laboratory in fluid thioglycollate medium. Initially Gram's stain and Fontana stains were done. Aerobic, anaerobic, and microaerophilic culture were put up. Antibiotic sensitivity test was done for aerobic isolates. RESULTS: Sixty samples yielded 121 isolates of which 78.34% were polymicrobial, 11.66% were monomicrobial and oral commensals were grown in 10% cases. Out of 121 isolates 91.74% were anaerobic, 7.43% were aerobic and 0.83% were microaerophilic. Fusobacterium species was the most common isolate among anaerobes. Using "paired t-test" "P" value was significant indicating significant reduction in colony count after phase-I periodontal therapy. CONCLUSION: This study has shown that anaerobic bacteria are important cause of chronic periodontitis, along with aerobes and microaerophilic organisms. Fusobacterium spp, Bacteroides fragilis, Porphyromonas spp and Prevotella intermedia are the most common anaerobic pathogens. Bacterial culture methods are still economical and gold standard.

High quality draft genome sequence and analysis of Pontibacter roseus type strain SRC-1(T) (DSM 17521(T)) isolated from muddy waters of a drainage system in Chandigarh, India.

Pontibacter roseus is a member of genus Pontibacter family Cytophagaceae, class Cytophagia. While the type species of the genus Pontibacter actiniarum was isolated in 2005 from a marine environment, subsequent species of the same genus have been found in different types of habitats ranging from seawater, sediment, desert soil, rhizosphere, contaminated sites, solar saltern and muddy water. Here we describe the features of Pontibacter roseus strain SRC-1(T) along with its complete genome sequence and annotation from a culture of DSM 17521(T). The 4,581,480 bp long draft genome consists of 12 scaffolds with 4,003 protein-coding and 50 RNA genes and is a part of Genomic Encyclopedia of Type Strains: KMG-I project.

Non-contiguous finished genome sequence of plant-growth promoting Serratia proteamaculans S4.

Serratia proteamaculans S4 (previously Serratia sp. S4), isolated from the rhizosphere of wild Equisetum sp., has the ability to stimulate plant growth and to suppress the growth of several soil-borne fungal pathogens of economically important crops. Here we present the non-contiguous, finished genome sequence of S. proteamaculans S4, which consists of a 5,324,944 bp circular chromosome and a 129,797 bp circular plasmid. The chromosome contains 5,008 predicted genes while the plasmid comprises 134 predicted genes. In total, 4,993 genes are assigned as protein-coding genes. The genome consists of 22 rRNA genes, 82 tRNA genes and 58 pseudogenes. This genome is a part of the project "Genomics of four rapeseed plant growth-promoting bacteria with antagonistic effect on plant pathogens" awarded through the 2010 DOE-JGI's Community Sequencing Program.

Complete genome sequence of the marine methyl-halide oxidizing Leisingera methylohalidivorans type strain (DSM 14336(T)), a representative of the Roseobacter clade.

Leisingera methylohalidivorans Schaefer et al. 2002 emend. Vandecandelaere et al. 2008 is the type species of the genus Leisingera. The genus belongs to the Roseobacter clade (Rhodobacteraceae, Alphaproteobacteria), a widely distributed lineage in marine environments. Leisingera and particularly L. methylohalidivorans strain MB2(T) is of special interest due to its methylotrophy. Here we describe the complete genome sequence and annotation of this bacterium together with previously unreported aspects of its phenotype. The 4,650,996 bp long genome with its 4,515 protein-coding and 81 RNA genes consists of three replicons, a single chromosome and two extrachromosomal elements with sizes of 221 kb and 285 kb.