Roseovarius pelagicus sp. nov., a facultatively anaerobic bacterium with potential for degrading polypropylene, isolated from Arctic seawater.

A Gram-stain-negative, facultatively anaerobic, non-motile, rod-shaped bacterial strain, designated HL-MP18T, was isolated from Arctic seawater after a prolonged incubation employing polypropylene as the sole carbon source. Phylogenetic analyses of the 16S rRNA gene sequence revealed that strain HL-MP18T was affiliated to the genus Roseovarius with close relatives Roseovarius carneus LXJ103T (96.8 %) and Roseovarius litorisediminis KCTC 32327T (96.5 %). The complete genome sequence of strain HL-MP18T comprised a circular chromosome of 3.86 Mbp and two circular plasmids of 0.17 and 0.24 Mbp. Genomic comparisons based on average nucleotide identity and digital DNA-DNA hybridization showed that strain HL-MP18T was consistently discriminated from its closely related taxa in the genus Roseovarius. Strain HL-MP18T showed optimal growth at 25 °C, pH 7.0 and 2.5 % (w/v) sea salts. The major cellular fatty acids were C18 : 1 ω6c and/or C18 : 1 ω7c (49.6 %), C19 : 0 cyclo ω8c (13.5 %), and C16 : 0 (12.8 %). The major respiratory quinone was ubiquinone-10. The polar lipids consisted of phosphatidylcholine, phosphatidylglycerol, an unidentified aminolipid and three unidentified lipids. The genomic DNA G+C content of the strain was 59.2 mol%. The phylogenetic, genomic, phenotypic and chemotaxonomic results indicate that strain HL-MP18T is distinguishable from the recognized species of the genus Roseovarius. Therefore, we propose that strain HL-MP18T represents a novel species belonging to the genus Roseovarius, for which the name Roseovarius pelagicus sp. nov. is proposed. The type strain is HL-MP18T (=KCCM 90405T=JCM 35639T).

Differences between bloodstream infections involving Gram-positive and Gram-negative anaerobes.

BACKGROUND: The objectives of this study were to describe differences between bloodstream infections involving Gram-positive (GP) and Gram-negative (GN) anaerobic bacteria. METHODS: Patients with clinically significant anaerobic bacteremia detected between October 2016 and July 2022 in a tertiary hospital in Granada (Spain) were retrospectively included. Species identification was performed by MALDI-TOF MS and/or molecular methods. The association between variables was analyzed using contingency tables, applying the chi-square test when expected frequencies were adequate and the Fisher exact test when not. Variables were gathered at the time of the first positive blood culture. RESULTS: Out of 237 cases of anaerobic bloodstream infections detected, 127 (53.6%) were GN. Crude mortality was 20.3%, corresponding to 48 patients who died of causes directly attributable to bacteremia. The presence of malignant disease (p = 0.011), abdominal and/or pelvic surgery (p = 0.001), and transplantation (p = 0.008) were significantly associated with bacteremia due to GN bacteria, while the presence of diabetes mellitus was significantly associated with bacteremia due to GP bacteria (p = 0.022). The presence of both septic shock and mortality was more frequently associated with bacteremia due to GN versus GP bacteria. CONCLUSIONS: The association of certain variables with the presence of bloodstream infections due to GP or GN anaerobic bacteria may assist in selecting the optimal empirical therapeutic approach and improving the outcome of patients with these types of infection.

Lesiones perirradiculares persistentes: revisión narrativa / Persistent periradicular lesions: a narrative review

La persistencia de lesiones perirradiculares luego del tra- tamiento endodóntico es un problema que requiere del clínico un conocimiento cabal de la histofisiología y de la histopato- logía del sistema de conductos radiculares del tejido pulpar y de los tejidos perirradiculares (periodonto y hueso); además de considerar siempre la posible existencia de enfermedades sistémicas que también pueden actuar como factores de in- fluencia. La presencia de bacterias remanentes a posteriori del tratamiento es considerada como una de las causas principales y más frecuentes para la perpetuación de las lesiones perirra- diculares. Sin embargo, existen otros factores causales, como la existencia de conductos laterales o accesorios infectados y no tratados, la reabsorción dentinaria interna, intercomunica- ciones, cul-de-sacs o istmos; que representan áreas de difícil acceso durante la instrumentación e irrigación. Cuando la cau- sa original se localiza en la zona perirradicular, como en los casos de actinomicosis, reacciones a cuerpo extraño, cristales de colesterol (CRCo) y granulomas o quistes con alto conte- nido de CRCo, la indicación más adecuada es el retratamiento y la cirugía periapical como complemento (AU)

The persistence of periradicular lesions after endodontic treatment is a problem that requires the doctor to have a thor- ough knowledge of the histophysiology and histopathology of the root canal system, the pulp tissue and periradicular tis- sues (periodontium and bone); as well as always considering the possible existence of systemic alterations that can also be influencing factors. Persisting bacteria within the root canal system after treatment is one of the major and most frequent causes for the perpetuation of periradicular lesions. Howev- er, there are other possible causal factors such as the exist- ence of untreated lateral or accessory canals, internal dentin resorption, intercommunications, cul-de-sacs or isthmuses; areas that represent a difficulty in access during instrumen- tation and irrigation. If the original cause is located in the periradicular area, in cases like actinomycosis, foreign-body reactions, cholesterol crystals (CRCo) and granulomas or cysts with high content of CRCo, retreatment coupled with periapical surgery is the best approach to treatment (AU)

Antimicrobial susceptibility pattern of oral gram negative anaerobes from Indian subjects.

OBJECTIVES: There is paucity of information on the antimicrobial susceptibility pattern of oral anaerobic bacteria. In this study, an attempt has been made to evaluate the antimicrobial susceptibility/resistance trend of oral Gram negative bacteria from Indian subjects. METHODS: Minimum inhibitory concentrations (MIC) of 304 isolates against twelve different antibiotics were determined using gradient diffusion MIC strips. The organisms were isolated and identified based on phenotypic characteristics and included Porphyromonas gingivalis, Prevotella species, Tannerella forsythia, Fusobacterium nucleatum, Aggregatibacter actinomycetemcoitans, Eickenella corrodens and Capnocytophaga species. For each antimicrobial agent, MIC50 and MIC90 were calculated and expressed. RESULTS: Resistance to azithromycin, clindamycin, and amoxicillin was observed in most of the anaerobic bacterial species studied. High degree of susceptibility was observed to amoxillin-clavulanic acid, doxycycline and moxifloxacin. A single strain of P. melaninogenica was resistant to moxifloxacin. The susceptibility pattern varied with cephalosporins among species. Ceftriaxone showed highest and cefazolin least efficacy among cephalosporins. All anaerobic bacteria tested were susceptible to metronidazole. Strains of T. forsythia were more resistant to several antibiotics than other anaerobic bacteria. All three species of capnophilic bacteria displayed high degree of resistance to metronidazole and significant resistance to amoxicillin, azithromycin, clindamycin, cefazolin and cefuroxime. CONCLUSIONS: Amoxicillin-clavulanic acid, doxycycline, moxifloxacin and metronidazole appeared to be the most effective drugs against gram negative anaerobic bacteria. However, the MIC50 and MIC90 values against metronidazole were on the higher side of the normal indicating a potential for developing resistance.

Development and application of aerobic, chemically defined media for Dysgonomonas.

Members of Dysgonomonas are Gram-stain-negative, non-motile, facultatively anaerobic coccobacilli originally described in relation to their isolation from stool and wounds of human patients (CDC group DF-3). More recently, Dysgonomonas have been found to be widely distributed in terrestrial environments and are particularly enriched in insect systems. Their prevalence in xylophagous insects such as termites and wood-feeding cockroaches, as well as in soil-fed microbial fuel cells, elicit interest in lignocellulose degradation and biofuel production, respectively. Their occurrence in mosquito and fruit fly have implications relating to symbiosis, host immunology and developmental biology. Additionally, their presence in termite, mosquito and nematode present novel opportunities for pest and vector control. Currently, the absolute growth requirements of Dysgonomonas are unknown, and they are commonly cultured under anaerobic conditions on complex media containing blood, peptones, tryptones, and yeast, plant or meat extracts. Restrictive and undefined culturing conditions preclude physiological and genetic studies, and thus further understanding of their metabolic potential. Here we describe the requirements for growth of termite-derived Dysgonomonas isolates and create parallel complex, defined and minimal media that permit vigorous and reliable aerobic growth. Furthermore, we show that these media can be used to easily enrich for Dysgonomonas isolates from densely-colonized and microbially-diverse environmental samples.

Periodontal Inflammation and the Risk of Cardiovascular Disease.

PURPOSE OF REVIEW: The role of oral bacteremia and periodontal inflammation driving atherosclerosis is still under investigation. This review article highlights the role of periodontal inflammation and oral microorganisms in the development and progression of atherosclerosis and cardiovascular diseases. RECENT FINDINGS: Association between periodontal and cardiovascular diseases has been well characterized, but causal correlation is yet to be established. For instance, untreated gingivitis can progress to periodontitis. Periodontal disease has been associated with several systemic diseases one of which is atherosclerosis. One possible association that was documented in literature is that poor oral hygiene leads to bacteremia, which in turn can cause bacterial growth over atherosclerotic coronary artery plaques and possibly worsen coronary artery disease. It is crucial that clinicians understand the association between periodontal and cardiovascular disease. A comprehensive treatment for periodontitis and re-establishment of a healthy periodontium can help in reduction of overall inflammation in the body. This may play an important role in prevention of cardiovascular disease, though future research is needed to establish this.

Mechanistic insights into the action of probiotics against bacterial vaginosis and its mediated preterm birth: An overview.

The human body is a reservoir of numerous micro-creatures; whose role is substantial and indispensable in the overall development of human beings. The advances in omic approaches have offered powerful means to decipher the core microbiome and metabolome diversities in a specific organ system. The establishment of lactobacilli in the female reproductive tract is thought to be a paramount prerequisite that maintains homeostatic conditions for a sustainable and healthy pregnancy. Nevertheless, a plethora of such Lactobacillus strains of vaginal source revealed probiotic phenotypes. The plummeting in the occurrence of lactobacilli in the vaginal ecosystem is associated with several adverse pregnancy outcomes (APOs). One such pathological condition is "Bacterial Vaginosis" (BV), a pathogen dominated gynecological threat. In this scenario, the ascending traffic of notorious Gram-negative/variable BV pathogens to the uterus is one of the proposed pathways that give rise to inflammation-related APOs like preterm birth. Since antibiotic resistance is aggravating among urogenital pathogens, the probiotics intervention remains one of the alternative biotherapeutic strategies to overcome BV and its associated APOs. Perhaps, the increased inclination towards the safer and natural biotherapeutic strategies rather than pharmaceutical drugs for maintaining gestational and reproductive health resulted in the use of probiotics in pregnancy diets. In this context, the current review is an attempt to highlight the microbiome and metabolites signatures of BV and non-BV vaginal ecosystem, inflammation or infection-related preterm birth, host-microbial interactions, role and effectiveness of probiotics to fight against aforesaid diseased conditions.

Surveillance of antimicrobial resistance in recent clinical isolates of Gram-negative anaerobic bacteria in a Greek University Hospital.

The aim of our study was to determine the antimicrobial susceptibility profiles of 267 Gram-negative clinically significant anaerobes, isolated between October 2016 and October 2019, in a Greek university hospital. The species identification was performed by conventional methods and using the Vitek 2 automated system. Antimicrobial susceptibility testing to determine the MICs was performed by the E-test method. The antimicrobial agents tested were penicillin, ampicillin, amoxicillin-clavulanic acid, piperacillin-tazobactam, cefoxitin, imipenem, meropenem, clindamycin, metronidazole, moxifloxacin, chloramphenicol and tigecycline. The results were interpreted using the CLSI and FDA breakpoints. The majority of the isolates belonged to Bacteroides fragilis group (58.8%), followed by Prevotella spp. (23.2%), Fusobacterium spp. (11.2%) and Veillonella spp. (6.4%). The most prevalent types of infection were skin and soft tissue infections (34.8%), and inta-abdomonal infections (29.6%). Among all isolates tested, the lowest rates of resistance (<5%) were detected to carbapenems, metronidazole, chloramphenicol and tigecycline. Resistance to piperacillin-tazobactam was observed in 5.4%, 24.6%, 3.3% and 17.6%, of B. fragilis, B. fragilis group, Fusobacterium spp. and Veillonella spp. isolates, respectively. Although a high prevalence of resistance to clindamycin, cefoxitin, and moxifloxacin, was detected particularly among members of the B. fragilis group, cefoxitin resistance was low for Prevotella spp. (3.2%), Fusobacterium spp. (3.3%) and Veillonella spp. (0%). Our findings underscore the need for periodic monitoring of antimicrobial resistance in order to guide empirical therapy.

Multiple factors drive the abundance and diversity of the diazotrophic community in typical farmland soils of China.

Biological nitrogen fixation plays an important role in nitrogen cycling by transferring atmospheric N2 to plant-available N in the soil. However, the diazotrophic activity and distribution in different types of soils remain to be further explored. In this study, 152 upland soils were sampled to examine the diazotrophic abundance, nitrogenase activity, diversity and community composition by quantitative polymerase chain reaction, acetylene reduction assay and the MiSeq sequencing of nifH genes, respectively. The results showed that diazotrophic abundance and nitrogenase activity varied among the three soil types. The diazotrophic community was mainly dominated by Bradyrhizobium, Azospirillum, Myxobacter, Desulfovibrio and Methylobacterium. The symbiotic diazotroph Bradyrhizobium was widely distributed among soils, while the distribution of free-living diazotrophs showed large variation and was greatly affected by multiple factors. Crop type and soil properties directly affected the diazotrophic ɑ-diversity, while soil properties, climatic factors and spatial distance together influenced the diazotrophic community. Network structures were completely different among all three types of soils, with most complex interactions observed in the Red soil. These findings suggest that diazotrophs have various activities and distributions in the three soil types, which played different roles in nitrogen input in agricultural soil in China, being driven by multiple environmental factors.

A 60-heme reductase complex from an anammox bacterium shows an extended electron transfer pathway.

The hydroxylamine oxidoreductase/hydrazine dehydrogenase (HAO/HDH) protein family constitutes an important group of octaheme cytochromes c (OCCs). The majority of these proteins form homotrimers, with their subunits being covalently attached to each other via a rare cross-link between the catalytic heme moiety and a conserved tyrosine residue in an adjacent subunit. This covalent cross-link has been proposed to modulate the active-site heme towards oxidative catalysis by distorting the heme plane. In this study, the crystal structure of a stable complex of an HAO homologue (KsHAOr) with its diheme cytochrome c redox partner (KsDH) from the anammox bacterium Kuenenia stuttgartiensis was determined. KsHAOr lacks the tyrosine cross-link and is therefore tuned to reductive catalysis. The molecular model of the KsHAOr-KsDH complex at 2.6 Šresolution shows a heterododecameric (α6ß6) assembly, which was also shown to be the oligomeric state in solution by analytical ultracentrifugation and multi-angle static light scattering. The 60-heme-containing protein complex reveals a unique extended electron transfer pathway and provides deeper insights into catalysis and electron transfer in reductive OCCs.

Induction and inhibition of oral malodor.

Volatile sulfur compounds (VSCs) such as hydrogen sulfide (H2 S) and methyl mercaptan (CH3 SH) are the main components of oral malodor, and are produced as the end products of the proteolytic processes of oral microorganisms. The main pathway of proteolysis is the metabolism of sulfur-containing amino acids by gram-negative anaerobic bacteria. Gram-positive bacteria may promote VSC production by gram-negative anaerobes by cleaving sugar chains from glycoproteins and thus providing proteins. A large variety of bacteria within the oral microbiota are thought to be involved in the complex phenomenon of halitosis. Oral microbiota associated with a lack of oral malodor, oral microbiota associated with severe and H2 S-dominant oral malodor, and oral microbiota associated with severe and CH3 SH-dominant oral malodor have been distinguished through molecular approaches using the 16S rRNA gene. Pathological halitosis may primarily be addressed through treatment of causative diseases. In all cases, plaque control is the basis of oral malodor control, and dentifrices, mouthwashes, and functional foods play a supplementary role in addition to brushing. Recently, the use of natural ingredients in products tends to be favored due to the increase in antibiotic-resistant strains and the side effects of some chemical ingredients. In addition, probiotics and vaccines are expected to offer new strategies for improving the oral conditions through mechanisms other than antibacterial agents.

The Role of Opioid Receptors in Immune System Function.

Research on the effects of opioids on immune responses was stimulated in the 1980s by the intersection of use of intravenous heroin and HIV infection, to determine if opioids were enhancing HIV progression. The majority of experiments administering opioid alkaloids (morphine and heroin) in vivo, or adding these drugs to cell cultures in vitro, showed that they were immunosuppressive. Immunosuppression was reported as down-regulation: of Natural Killer cell activity; of responses of T and B cells to mitogens; of antibody formation in vivo and in vitro; of depression of phagocytic and microbicidal activity of neutrophils and macrophages; of cytokine and chemokine production by macrophages, microglia, and astrocytes; by sensitization to various infections using animal models; and by enhanced replication of HIV in vitro. The specificity of the receptor involved in the immunosuppression was shown to be the mu opioid receptor (MOR) by using pharmacological antagonists and mice genetically deficient in MOR. Beginning with a paper published in 2005, evidence was presented that morphine is immune-stimulating via binding to MD2, a molecule associated with Toll-like Receptor 4 (TLR4), the receptor for bacterial lipopolysaccharide (LPS). This concept was pursued to implicate inflammation as a mechanism for the psychoactive effects of the opioid. This review considers the validity of this hypothesis and concludes that it is hard to sustain. The experiments demonstrating immunosuppression were carried out in vivo in rodent strains with normal levels of TLR4, or involved use of cells taken from animals that were wild-type for expression of TLR4. Since engagement of TLR4 is universally accepted to result in immune activation by up-regulation of NF-κB, if morphine were binding to TLR4, it would be predicted that opioids would have been found to be pro-inflammatory, which they were not. Further, morphine is immunosuppressive in mice with a defective TLR4 receptor. Morphine and morphine withdrawal have been shown to permit leakage of Gram-negative bacteria and LPS from the intestinal lumen. LPS is the major ligand for TLR4. It is proposed that an occult variable in experiments where morphine is being proposed to activate TLR4 is actually underlying sepsis induced by the opioid.

Ultrafast fabrication of thermally stable protein-coated silver iodide nanoparticles for solid-state superionic conductors.

Solid-state ionic conductor is an essential and critical part of electrochemical devices such as batteries and sensors. Nano-sized silver iodide (AgI) is the most promising ionic conductor due to its superionic conductivity at room temperature. In recent years, proteins have been used as organic templates to obtain high-performance solid-state ionic conductors as well as to extend their applications in a biosensor. Here, we report the unprecedented ultrafast synthesis of thermally stable protein-coated AgI nanoparticles (NPs) through the photo-irradiation method for solid-state electrolyte. The synthesis was performed using a hyperthermostable bacterial ß-glucosidase. The protein-coated AgI NPs with an approximate diameter of 13 nm showed that the controllable transition from the α- to ß-/γ-phase was drastically suppressed down to 41 °C in the cooling process. After drying, the product represents a thermally stable organic-inorganic hybrid system with superionic conductivity. It is noteworthy that the superionic conductivity (σ ˜ 0.14 S/cm at 170 °C) of thermally stable protein-coated AgI NPs is maintained during several thermal cycles (25-170 °C). To our knowledge, this is the first report showing the diffusion of mobile Ag+ ions on the surface of the AgI NPs through a protein matrix. The facile synthesis method and high performance of the protein-coated AgI NPs may provide a latent application in the mass production of nanobatteries and other technological applications.

Pickering emulsions stabilized nanocellulosic-based nanoparticles for coumarin and curcumin nanoencapsulations: In vitro release, anticancer and antimicrobial activities.

Coumarin and curcumin have a wide spectrum of biological and pharmacological activities including antioxidant, anti-inflammatory, antimicrobial and anticancer but hindered therapeutic applications due to low stability and poor solubility in water. The main objective of the current study was to overcome these drawbacks via improved bioavailability by nanoencapsulated emulsions. Pickering emulsion (PE) via oil-in-water approach were stabilized by aminated nanocellulose (ANC) particles through application of a full factorial optimization design for nanoemulsions containing different composition of oil phase with medium chain triglyceride (MCT) and Tween 80. The fabricated nanoemulsions and PEs with average particle sizes (≤150 nm) were obtained. Influencing factors such as ANC concentration, storage time and pH on the stability of emulsions were examined alongside zeta potentials. Encapsulation efficiency (EE) of coumarin and curcumin were determined as >90%. Release kinetic profiles for encapsulated PEs displayed sustained release with supposed increase bioavailability. Higher release percent were detected for curcumin encapsulated PE in contrast to coumarin. In vitro cytotoxicity evaluation for coumarin and curcumin loaded PEs were further investigated for anticancer and antimicrobial activities using human cell lines (L929 and MCF-7) and different microorganisms (Gram (+), Gram (-) and fungi), respectively. The results clearly demonstrated PE coumarin and curcumin as promising candidates to inhibit microbial growth and to prevent preferential killing of cancer cells compared to normal cells.

A Prospective Evaluation of Two Rapid Phenotypical Antimicrobial Susceptibility Technologies for the Diagnostic Stewardship of Sepsis.

Rapid identification of bloodstream pathogens by MALDI-TOF MS and the recently introduced rapid antimicrobial susceptibility testing (rAST) directly from positive blood cultures allow clinicians to promptly achieve a targeted therapy, especially for multidrug resistant microorganisms. In the present study, we propose a comparison between phenotypical rASTs performed in light-scattering technology (Alfred 60AST, Alifax®) and fluorescence in situ hybridization (Pheno™, Accelerate) directly from positive blood cultures, providing results in 4-7 hours. Blood samples from 67 patients admitted to the Azienda Ospedaliero-Universitaria Pisana were analyzed. After the direct MALDI-TOF MS identification, the rAST was performed at the same time both on Alfred 60AST and Pheno. Alfred 60AST provided qualitative results, interpreted in terms of clinical categories (SIR). Pheno provided identification and MIC values for each antibiotic tested. Results were compared to the broth microdilution assay (SensiTitre™, Thermo Fisher Scientific), according to EUCAST rules. Using Alfred 60AST, an agreement was reached, 91.1% for Gram-negative and 95.7% for Gram-positive bacteria, while using Pheno, the agreement was 90.6% for Gram-negative and 100% for Gram-positive bacteria. Both methods provided reliable results; Alfred 60AST combined with MALDI-TOF MS proved itself faster and cheaper. Pheno provided identification and MIC determination in a single test and, although more expensive, may be useful whenever MIC value is necessary and where MALDI-TOF MS is not present.

Abditibacterium utsteinense sp. nov., the first cultivated member of candidate phylum FBP, isolated from ice-free Antarctic soil samples.

Most bacterial lineages are known only by molecular sequence data from environmental surveys and represent the uncultivated majority. One of these lineages, candidate phylum FBP, is widespread in extreme environments on Earth, ranging from polar and desert ecosystems to wastewater and contaminated mine sites. Here we report on the characterization of strain LMG 29911T, the first cultivated representative of the FBP lineage. The strain was isolated from a terrestrial surface sample from Utsteinen, Sør Rondane Mountains, East Antarctica and is a Gram-negative, aerobic, oligotrophic chemoheterotrophic bacterium. It displays growth in a very narrow pH range, use of only a limited number of carbon sources, but also a metabolism optimized for survival in low-nutrient habitats. Remarkably, phenotypic and genome analysis indicated an extreme resistance against antibiotics and toxic compounds. We propose the names Abditibacterium utsteinense for this bacterium and Abditibacteriota for the former candidate phylum FBP. Furthermore, inter- and intra-phylum relationships indicate Armatimonadetes, a neighboring lineage to the Abditibacteriota, to be a superphylum.

Aerobic bacteriological profile and antimicrobial susceptibility pattern of pus isolates from tertiary care hospital in India.

INTRODUCTION: Pyogenic infections are an important cause of sepsis. These infections are difficult to treat because of the pathogens with increasing antibiotic resistance. It is important to know the pathogens causing the infections and its antibiotic susceptibility for proper management of the patients. METHODOLOGY: A retrospective analysis of 1428 culture positive pus and tissue samples received in the department of microbiology from various departments in the hospital between January 2012 to 2017 was performed. Data regarding the pathogen isolated and its antimicrobial susceptibility were collected and analyzed. The specimens were primarily processed, as per standard methods. Identification and susceptibility testing was done using the Vitek-2C system. RESULTS: Among the samples males outnumbered females (M: F-2.5:1) and the median age was 47 years. The total number of patients were 1428 with total number of isolates being 1525 as in our study monomicrobial infections were seen in 93.2% (1331/1428) patients whereas combined infections with growth of two pathogens in 6.8% (97/1428). Gram-negative bacilli were isolated in 68.3% (1042/1525). Among the Gram-negative bacilli Escherichia coli was the major pathogen isolated (38.6%, 403/1042). Gram positive organisms were isolated in 31.6% (483/1525) of cases and Staphylococcus aureus was the predominant organism isolated (91.7%, 443/483). Rare pathogens like Burkholderia pseudomallei in 3 patients and Nocardia in one patient were also isolated. CONCLUSION: This study emphasizes to understand the common organisms isolated from wound infections and it helps in empirical treatment of patients based on antibiotic susceptibility patterns.

Non-covalent interaction between CA-TAT and calf thymus DNA: Deciphering the binding mode by in vitro studies.

CA-TAT, a novel peptide analog, was modified at the N-terminus of TAT (47-57), the cell-penetrating peptide transacting activator of transcription, by attaching cecropin A (1-7). CA-TAT, TAT (47-57), and cecropin A (1-7) were synthesized using standard Fmoc solid-phase peptide synthesis procedures, purified using reversed-phase high performance liquid chromatography (RP-HPLC), and characterized using ESI-MS. CA-TAT demonstrated antibacterial activities against bacteria with low hemolysis (MHC > 128 µM). The minimum inhibitory concentration (MIC) values of CA-TAT were in the range of 1-16 µM, which completely inhibited both gram-positive and gram-negative bacteria. The interactions between CA-TAT or TAT (47-57) and calf thymus DNA (ct-DNA) were investigated using multi-spectroscopic techniques and viscometry. The results showed that both CA-TAT and TAT (47-57) can interact with DNA via the minor groove-binding mode, and binding constant was calculated to be 2.83 × 105 L mol-1 at 310 K, which is lower than that with the classical intercalation binder ethidium bromide (EB). Compared with TAT (47-57) or cecropin A (1-7), CA-TAT combined with DNA much closer. The study results suggest that CA-TAT can be used as a novel antibacterial peptide in the development of new antibiotics because of its antibacterial activity that targets intracellular DNA.