Development of 2nd generation aminomethyl spectinomycins that overcome native efflux in Mycobacterium abscessus.

Mycobacterium abscessus (Mab), a nontuberculous mycobacterial (NTM) species, is an emerging pathogen with high intrinsic drug resistance. Current standard-of-care therapy results in poor outcomes, demonstrating the urgent need to develop effective antimycobacterial regimens. Through synthetic modification of spectinomycin (SPC), we have identified a distinct structural subclass of N-ethylene linked aminomethyl SPCs (eAmSPCs) that are up to 64-fold more potent against Mab over the parent SPC. Mechanism of action and crystallography studies demonstrate that the eAmSPCs display a mode of ribosomal inhibition consistent with SPC. However, they exert their increased antimicrobial activity through enhanced accumulation, largely by circumventing efflux mechanisms. The N-ethylene linkage within this series plays a critical role in avoiding TetV-mediated efflux, as lead eAmSPC 2593 displays a mere fourfold susceptibility improvement against Mab ΔtetV, in contrast to the 64-fold increase for SPC. Even a minor shortening of the linkage by a single carbon, akin to 1st generation AmSPC 1950, results in a substantial increase in MICs and a 16-fold rise in susceptibility against Mab ΔtetV. These shifts suggest that longer linkages might modify the kinetics of drug expulsion by TetV, ultimately shifting the equilibrium towards heightened intracellular concentrations and enhanced antimicrobial efficacy. Furthermore, lead eAmSPCs were also shown to synergize with various classes of anti-Mab antibiotics and retain activity against clinical isolates and other mycobacterial strains. Encouraging pharmacokinetic profiles coupled with robust efficacy in Mab murine infection models suggest that eAmSPCs hold the potential to be developed into treatments for Mab and other NTM infections.

Electron tomography unravels new insights into fiber cell wall nanostructure; exploring 3D macromolecular biopolymeric nano-architecture of spruce fiber secondary walls.

Lignocellulose biomass has a tremendous potential as renewable biomaterials for fostering the "bio-based society" and circular bioeconomy paradigm. It requires efficient use and breakdown of fiber cell walls containing mainly cellulose, hemicellulose and lignin biopolymers. Despite their great importance, there is an extensive debate on the true structure of fiber walls and knowledge on the macromolecular nano-organization is limited and remains elusive in 3D. We employed dual-axis electron tomography that allows visualization of previously unseen 3D macromolecular organization/biopolymeric nano-architecture of the secondary S2 layer of Norway spruce fiber wall. Unprecedented 3D nano-structural details with novel insights into cellulose microfibrils (~ 2 nm diameter), macrofibrils, nano-pore network and cell wall chemistry (volume %) across the S2 were explored and quantified including simulation of structure related permeability. Matrix polymer association with cellulose varied between microfibrils and macrofibrils with lignin directly associated with MFs. Simulated bio-nano-mechanical properties revealed stress distribution within the S2 and showed similar properties between the idealized 3D model and the native S2 (actual tomogram). Present work has great potential for significant advancements in lignocellulose research on nano-scale understanding of cell wall assembly/disassembly processes leading to more efficient industrial processes of functionalization, valorization and target modification technologies.

Immunothrombosis and vascular heterogeneity in cerebral cavernous malformation.

Cerebral cavernous malformation (CCM) is a neurovascular disease that results in various neurological symptoms. Thrombi have been reported in surgically resected CCM patient biopsies, but the molecular signatures of these thrombi remain elusive. Here, we investigated the kinetics of thrombi formation in CCM and how thrombi affect the vasculature and contribute to cerebral hypoxia. We used RNA sequencing to investigate the transcriptome of mouse brain endothelial cells with an inducible endothelial-specific Ccm3 knock-out (Ccm3-iECKO). We found that Ccm3-deficient brain endothelial cells had a higher expression of genes related to the coagulation cascade and hypoxia when compared with wild-type brain endothelial cells. Immunofluorescent assays identified key molecular signatures of thrombi such as fibrin, von Willebrand factor, and activated platelets in Ccm3-iECKO mice and human CCM biopsies. Notably, we identified polyhedrocytes in Ccm3-iECKO mice and human CCM biopsies and report it for the first time. We also found that the parenchyma surrounding CCM lesions is hypoxic and that more thrombi correlate with higher levels of hypoxia. We created an in vitro model to study CCM pathology and found that human brain endothelial cells deficient for CCM3 expressed elevated levels of plasminogen activator inhibitor-1 and had a redistribution of von Willebrand factor. With transcriptomics, comprehensive imaging, and an in vitro CCM preclinical model, this study provides experimental evidence that genes and proteins related to the coagulation cascade affect the brain vasculature and promote neurological side effects such as hypoxia in CCMs. This study supports the concept that antithrombotic therapy may be beneficial for patients with CCM.

Biophysical analysis of the Mycobacteria tuberculosis peptide binding protein DppA reveals a stringent peptide binding pocket.

The peptide binding protein DppA is an ABC transporter found in prokaryotes that has the potential to be used as drug delivery tool for hybrid antibiotic compounds. Understanding the motifs and structures that bind to DppA is critical to the development of these bivalent compounds. This study focused on the biophysical analysis of the MtDppA from M. tuberculosis. Analysis of the crystal structure revealed a SVA tripeptide was co-crystallized with the protein. Further peptide analysis demonstrated MtDppA shows very little affinity for dipeptides but rather preferentially binds to peptides that are 3-4 amino acids in length. The structure-activity relationships (SAR) between MtDppA and tripeptides with varied amino acid substitutions were evaluated using thermal shift, SPR, and molecular dynamics simulations. Efforts to identify novel ligands for use as alternative scaffolds through the thermal shift screening of 35,000 compounds against MtDppA were unsuccessful, indicating that the MtDppA binding pocket is highly specialized for uptake of peptides. Future development of compounds that seek to utilize MtDppA as a drug delivery mechanism, will likely require a tri- or tetrapeptide component with a hydrophobic -non-acidic peptide sequence.

Palmdelphin Regulates Nuclear Resilience to Mechanical Stress in the Endothelium.

BACKGROUND: PALMD (palmdelphin) belongs to the family of paralemmin proteins implicated in cytoskeletal regulation. Single nucleotide polymorphisms in the PALMD locus that result in reduced expression are strong risk factors for development of calcific aortic valve stenosis and predict severity of the disease. METHODS: Immunodetection and public database screening showed dominant expression of PALMD in endothelial cells (ECs) in brain and cardiovascular tissues including aortic valves. Mass spectrometry, coimmunoprecipitation, and immunofluorescent staining allowed identification of PALMD partners. The consequence of loss of PALMD expression was assessed in small interferring RNA-treated EC cultures, knockout mice, and human valve samples. RNA sequencing of ECs and transcript arrays on valve samples from an aortic valve study cohort including patients with the single nucleotide polymorphism rs7543130 informed about gene regulatory changes. RESULTS: ECs express the cytosolic PALMD-KKVI splice variant, which associated with RANGAP1 (RAN GTP hydrolyase activating protein 1). RANGAP1 regulates the activity of the GTPase RAN and thereby nucleocytoplasmic shuttling via XPO1 (Exportin1). Reduced PALMD expression resulted in subcellular relocalization of RANGAP1 and XPO1, and nuclear arrest of the XPO1 cargoes p53 and p21. This indicates an important role for PALMD in nucleocytoplasmic transport and consequently in gene regulation because of the effect on localization of transcriptional regulators. Changes in EC responsiveness on loss of PALMD expression included failure to form a perinuclear actin cap when exposed to flow, indicating lack of protection against mechanical stress. Loss of the actin cap correlated with misalignment of the nuclear long axis relative to the cell body, observed in PALMD-deficient ECs, Palmd-/- mouse aorta, and human aortic valve samples derived from patients with calcific aortic valve stenosis. In agreement with these changes in EC behavior, gene ontology analysis showed enrichment of nuclear- and cytoskeleton-related terms in PALMD-silenced ECs. CONCLUSIONS: We identify RANGAP1 as a PALMD partner in ECs. Disrupting the PALMD/RANGAP1 complex alters the subcellular localization of RANGAP1 and XPO1, and leads to nuclear arrest of the XPO1 cargoes p53 and p21, accompanied by gene regulatory changes and loss of actin-dependent nuclear resilience. Combined, these consequences of reduced PALMD expression provide a mechanistic underpinning for PALMD's contribution to calcific aortic valve stenosis pathology.

Propranolol Reduces the Development of Lesions and Rescues Barrier Function in Cerebral Cavernous Malformations: A Preclinical Study.

[Figure: see text].

17-DMAG dually inhibits Hsp90 and histone lysine demethylases in alveolar rhabdomyosarcoma.

Histone lysine demethylases (KDMs) play critical roles in oncogenesis and therefore may be effective targets for anticancer therapy. Using a time-resolved fluorescence resonance energy transfer demethylation screen assay, in combination with multiple orthogonal validation approaches, we identified geldanamycin and its analog 17-DMAG as KDM inhibitors. In addition, we found that these Hsp90 inhibitors increase degradation of the alveolar rhabdomyosarcoma (aRMS) driver oncoprotein PAX3-FOXO1 and induce the repressive epigenetic mark H3K9me3 and H3K36me3 at genomic loci of PAX3-FOXO1 targets. We found that as monotherapy 17-DMAG significantly inhibits expression of PAX3-FOXO1 target genes and multiple oncogenic pathways, induces a muscle differentiation signature, delays tumor growth and extends survival in aRMS xenograft mouse models. The combination of 17-DMAG with conventional chemotherapy significantly enhances therapeutic efficacy, indicating that targeting KDM in combination with chemotherapy may serve as a therapeutic approach to PAX3-FOXO1-positive aRMS.

Nail Gun Suicide: An Atypical Case Report and Review of the Literature.

ABSTRACT: Nail guns are pneumatically driven or powder-actuated tools, which are used to drive nails into wood or concrete. A 42-year-old man, who was a builder by profession and history of antidepressant use, was found dead in his vehicle, holding a "Ramset" nail gun in his right hand. A straight metal nail and a book with a small hole were recovered from the scene.At autopsy, an irregularly circular puncture wound was seen on the forehead and a cruciate laceration was seen on the posterior aspect of the scalp. No burning, blackening, or tattooing was present around either injury. Both internal and external beveling was present with the latter being relatively larger. Toxicological analysis revealed alcohol and methamphetamine in blood. Psychiatric history and substance abuse must also be considered when individuals in construction industry are given access to tools like nail guns.Several unique features not previously reported were observed in this case. The deceased had overcome the built-in safety mechanism of the nail gun, by placing a book in between his forehead and muzzle. Another unique feature is that the nail had exited the cranium. Beveling, a feature commonly found in firearm injuries, was also seen in this case.

Survey on postmortem screening and management of COVID-19 related deaths.

The COVID-19 pandemic is associated with a high case fatality rate in some countries even thought the majority of cases are asymptomatic. Scientific studies on this novel virus is limited and there is uncertainty regarding the best practices for death investigations both in terms of detection of the disease as well as autopsy safety. An online survey was conducted to identify how different institutions responded to the screening and management of dead bodies during the early phase of the pandemic from January to May. A questionnaire was developed using Google Forms and data was collected from 14 different forensic and pathological institutions in 9 countries. None of the institutions had performed any screening prior to March. Four institutions stated that screening was done routinely. In total, 322 cases had been screened using RT-PCR, out of which 40 positive cases were detected among four institutions. The commonest types of samples obtained were nasopharyngeal and oropharyngeal swabs which also had the highest rates of positivity followed by tracheal swab. Blood, swabs from cut surfaces of lung and lung tissue also gave positive results in some cases. Majority of the positive cases were > 65 years with a history suggestive of respiratory infection and were clinically suspected to have COVID-19 before death. Except for one institution which performed limited dissections, standard autopsies were conducted on all positive cases. Disposal of bodies involved the use of sealed body bags and labelling as COVID positive. Funeral rites were restricted and none of the institutions advocated cremation. There were no reports of disease transmission to those who handled COVID positive bodies.

Discovery and Characterization of the Antimetabolite Action of Thioacetamide-Linked 1,2,3-Triazoles as Disruptors of Cysteine Biosynthesis in Gram-Negative Bacteria.

Increasing rates of drug-resistant Gram-negative (GN) infections, combined with a lack of new GN-effective antibiotic classes, are driving the need for the discovery of new agents. Bacterial metabolism represents an underutilized mechanism of action in current antimicrobial therapies. Therefore, we sought to identify novel antimetabolites that disrupt key metabolic pathways and explore the specific impacts of these agents on bacterial metabolism. This study describes the successful application of this approach to discover a new series of chemical probes, N-(phenyl)thioacetamide-linked 1,2,3-triazoles (TAT), that target cysteine synthase A (CysK), an enzyme unique to bacteria that is positioned at a key juncture between several fundamental pathways. The TAT class was identified using a high-throughput screen against Escherichia coli designed to identify modulators of pathways related to folate biosynthesis. TAT analog synthesis demonstrated a clear structure-activity relationship, and activity was confirmed against GN antifolate-resistant clinical isolates. Spontaneous TAT resistance mutations were tracked to CysK, and mode of action studies led to the identification of a false product formation mechanism between the CysK substrate O-acetyl-l-serine and the TATs. Global transcriptional responses to TAT treatment revealed that these antimetabolites impose substantial disruption of key metabolic networks beyond cysteine biosynthesis. This study highlights the potential of antimetabolite drug discovery as a promising approach to the discovery of novel GN antibiotics and the pharmacological promise of TAT CysK probes.

Next Generation of Tn7-Based Single-Copy Insertion Elements for Use in Multi- and Pan-Drug-Resistant Strains of Acinetobacter baumannii.

The purpose of this study was to create single-copy gene expression systems for use in genomic manipulations of multidrug-resistant (MDR) and extensively drug-resistant (XDR) clinical isolates of Acinetobacter baumannii In this study, mini-Tn7 vectors with zeocin and apramycin selection markers were created by cloning the ble and aac(3)-IV genes, respectively, enabling either inducible gene expression (pUC18T-mini-Tn7T-Zeo-LAC and pUC18T-mini-Tn7T-Apr-LAC) or expression from native or constitutive promoters (pUC18T-mini-Tn7T-Zeo and pUC18T-mini-Tn7T-Apr). The selection markers of these plasmids are contained within a Flp recombinase target (FRT) cassette, which can be used to obtain unmarked mini-Tn7 insertions upon introduction of a source of Flp recombinase. To this end, site-specific excision vectors pFLP2A and pFLP2Z (containing apramycin and zeocin selection markers, respectively) were created in this study as an accessory to the mini-Tn7 vectors described above. Combinations of these novel mini-Tn7 plasmids and their compatible pFLP2Z or pFLP2A accessory plasmid were used to generate unmarked insertions in MDR clinical isolates of A. baumannii In addition, several fluorescent markers were cloned and inserted into MDR and XDR clinical isolates of A. baumannii via these apramycin and zeocin mini-Tn7 constructs to demonstrate their application.IMPORTANCEAcinetobacter baumannii is a high-priority pathogen for which research on mechanisms of resistance and virulence is a critical need. Commonly used antibiotic selection markers are not suitable for use in MDR and XDR isolates of A. baumannii due to the high antibiotic resistance of these isolates, which poses a barrier to the study of this pathogen. This study demonstrates the practical potential of using apramycin and zeocin mini-Tn7- and Flp recombinase-encoded constructs to carry out genomic manipulations in clinical isolates of A. baumannii displaying MDR and XDR phenotypes.

Pulmonary artery dissection-A review of 150 cases.

Pulmonary artery dissection (PAD) is considered to be a rare condition with a very high mortality. Since a comprehensive review on PAD has not yet been done, we analysed all the available reports on PAD. In this analysis and review we searched the databases; Medline, PubMed Central, Directory of Open Access Journals, Google Scholar using the search term "Pulmonary Artery Dissection" with no language restrictions. In the 150 cases of PAD reported from 1842 to June 2018, the average age at diagnosis was 44.8 years with a male to female ratio of 1.1:1. Diagnosis was made in 49.3% of the males in the third and fourth decades, and 55.4% of the females in the fifth and sixth decades. The primary underlying causes were pulmonary hypertension and heart diseases, both congenital (mainly PDA) and acquired. The commonest clinical presentations were dyspnoea and chest pain. The best investigation of diagnosis was CT scan. The pulmonary trunk was the site of dissection in 72.5%. Surgical treatment, or medical management followed by surgery, had the best success rates. The overall survival rate which was 10.9% up to the year 2000, increased to 59.3% thereafter. If PAD was diagnosed ante-mortem, 70.5% survived. Haemopericardium / cardiac tamponade was seen at autopsy in 84.2%. PAD is not as rare, nor as fatal as believed, and with a high index of suspicion and appropriate investigations, an early diagnosis of PAD can be made and successful treatment instituted.

New ß-lactam - Tetramic acid hybrids show promising antibacterial activities.

ß-Lactams are the most important class of antibiotics, for which the emergence of resistance threatens their utility. As such, we explored the extent to which the tetramic acid motif, frequently found in naturally occurring antibiotics, can be used to generate novel ß-lactam antibiotics with improved antibacterial activity. We synthesized new ampicillin - tetramic acid, cephalosporin - tetramic acid, and cephamycin - tetramic acid analogs and evaluated their activities against problematic Gram-positive and Gram-negative pathogens. Amongst the analogs, a 7-aminocephalosporanic acid analog, 3397, and a 7-amino-3-vinyl cephalosporanic acid, 3436, showed potent activities against S. aureus NRS 70 (MRSA) with MICs of 6.25 µg/mL and 3.13 µg/mL respectively. These new analogs were ≥16-fold more potent than cefaclor and cephalexin. Additionally, a Δ2 cephamycin - tetramic acid analog 3474 which contained a basic guanidinium substituent at the 5-position of the tetramic acid core displayed potent activity against several clinical strains of K. pneumoniae and E. coli.

Is it appropriate to use WHO Multicentre Growth Reference Study standards to assess the growth parameters of Sri Lankan babies? A single-centre cross-sectional study.

OBJECTIVE: To compare the anthropometric measurements of newborns in a tertiary care hospital in Sri Lanka, with WHO standards. METHODS: Birth weight, length and occipitofrontal circumference (OFC) of 400 consecutive, term newborns of healthy mothers were measured in a tertiary care hospital. RESULTS: 400 subjects were approached and seven were excluded, concluding the study population to 184 boys and 209 females. Medians of birth weight, length and OFC were 3000 g, 49.95 cm and 34.15 cm of males and IQRs were 555.00, 2.70 and 1.70, respectively. For females, the medians of birth weight, length and OFC were 2900 g, 48.9 cm and 34.00 cm with IQRs of 450.00, 2.70 and 1.50, respectively. The two-tailed t-test revealed that median weights of males (t=9.632) and females (t=12.04) and OFC of males (t=3.98) were significantly lower than the WHO medians. There was a significant association of birth weight, with mother's prepregnancy weight, in males (ß coefficient=12.629 with 95% CI 6.275 to 18.982) and females (ß coefficient=5.880, 95% CI 1.434 to 10.325). Significant associations of length (ß coefficient=0.046, 95% CI 0.012 to 0.080) and OFC (ß coefficient=0.033, 95% CI 0.014 to 0.053) with mother's prepregnancy weight in males and length (ß coefficient=0.084, 95% CI 0.022 to 0.145) and weight (ß coefficient=10.780, 95% CI 0.93 to 20.629) with maternal age in females were found. Furthermore, birth weight in males was significantly associated with maternal height (ß coefficient=10.899, 95% CI 0.552 to 21.247). Education level, ethnicity and parity showed no significant associations with above parameters. CONCLUSION: The median weights of both sexes and OFC in males were significantly lower than the WHO standards. Island-wide studies are indicated to evaluate the appropriateness of applying WHO standards to Sri Lankan newborns.

Effect of Incubation Temperature on Antibiotic Resistance and Virulence Factors of Acinetobacter baumannii ATCC 17978.

Acinetobacter baumannii is a notorious opportunistic pathogen that is prevalent mainly in hospital settings. The ability of A. baumannii to adapt and to survive in a range of environments has been a key factor for its persistence and success as an opportunistic pathogen. In this study, we investigated the effect of temperature on the clinically relevant phenotypes displayed by A. baumannii at 37°C and 28°C. Surface-associated motility was significantly reduced at 28°C, while biofilm formation on plastic surfaces was increased at 28°C. Decreased susceptibility to aztreonam and increased susceptibility to trimethoprim-sulfamethoxazole were observed at 28°C. No differences in virulence, as assayed in a Galleria mellonella model, were observed. Proteomic analysis showed differential expression of 629 proteins, of which 366 were upregulated and 263 were downregulated at 28°C. Upregulation of the Csu and iron uptake proteins at 28°C was a key finding for understanding some of the phenotypes displayed by A. baumannii at 28°C.

Synthesis and Evaluation of Thiazolidine Amide and N-Thiazolyl Amide Fluoroquinolone Derivatives.

In an effort to develop new fluoroquinolones, we synthesized eight compounds and tested them against a panel of bacteria. The design of these compounds was guided by the introduction of the isothiazoloquinolone motif. The three most active compounds in this series, 8-10, demonstrated good antibacterial activity against methicillin-sensitive Staphylococcus aureus and healthcare-acquired methicillin-resistant Staphylococcus aureus (MIC 0.62-6.3 µg/mL). Further, when these three active compounds were tested for their inhibitory effects on bacterial enzymes, compound 9 was the most effective agent exhibiting IC50 values of 33.9 and 116.5 µM in the S. aureus deoxyribonucleic acid (DNA) gyrase supercoiling and topoisomerase IV decatenation assays, respectively.

Comparison of traditional field retting and Phlebia radiata Cel 26 retting of hemp fibres for fibre-reinforced composites.

Classical field retting and controlled fungal retting of hemp using Phlebia radiata Cel 26 (a mutant with low cellulose degrading ability) were compared with pure pectinase treatment with regard to mechanical properties of the produced fibre/epoxy composites. For field retting a classification of the microbial evolution (by gene sequencing) and enzyme profiles were conducted. By phylogenetic frequency mapping, different types of fungi, many belonging to the Ascomycota phylum were found on the fibres during the first 2 weeks of field retting, and thereafter, different types of bacteria, notably Proteobacteria, also proliferated on the field retted fibres. Extracts from field retted fibres exhibited high glucanase activities, while extracts from P. radiata Cel 26 retted fibres showed high polygalacturonase and laccase activities. As a result, fungal retting gave a significantly higher glucan content in the fibres than field retting (77 vs. 67%) and caused a higher removal of pectin as indicated by lower galacturonan content of fibres (1.6%) after fibres were retted for 20 days with P. radiata Cel 26 compared to a galacturonan content of 3.6% for field retted fibres. Effective fibre stiffness increased slightly after retting with P. radiata Cel 26 from 65 to 67 GPa, while it decreased after field retting to 52 GPa. Effective fibre strength could not be determined similarly due to variations in fibre fracture strain and fibre-matrix adhesion. A maximum composite strength with 50 vol% fibres of 307 MPa was obtained using P. radiata Cel 26 compared to 248 MPa with field retting.

Prevalence of antibiotic resistance genes in bacterial communities associated with Cladophora glomerata mats along the nearshore of Lake Ontario.

The alga Cladophora glomerata can erupt in nuisance blooms throughout the lower Great Lakes. Since bacterial abundance increases with the emergence and decay of Cladophora, we investigated the prevalence of antibiotic resistance (ABR) in Cladophora-associated bacterial communities up-gradient and down-gradient from a large sewage treatment plant (STP) on Lake Ontario. Although STPs are well-known sources of ABR, we also expected detectable ABR from up-gradient wetland communities, since they receive surface run-off from urban and agricultural sources. Statistically significant differences in aquatic bacterial abundance and ABR were found between down-gradient beach samples and up-gradient coastal wetland samples (ANOVA, Holm-Sidak test, p < 0.05). Decaying and free-floating Cladophora sampled near the STP had the highest bacterial densities overall, including on ampicillin- and vancomycin-treated plates. However, quantitative polymerase chain reaction analysis of the ABR genes ampC, tetA, tetB, and vanA from environmental communities showed a different pattern. Some of the highest ABR gene levels occurred at the 2 coastal wetland sites (vanA). Overall, bacterial ABR profiles from environmental samples were distinguishable between living and decaying Cladophora, inferring that Cladophora may control bacterial ABR depending on its life-cycle stage. Our results also show how spatially and temporally dynamic ABR is in nearshore aquatic bacteria, which warrants further research.

Multi-omics approach to study global changes in a triclosan-resistant mutant strain of Acinetobacter baumannii ATCC 17978.

Acinetobacter baumannii AB042, a triclosan-resistant mutant strain, was examined for modulated gene expression using whole-genome sequencing, transcriptomics and proteomics in order to understand the mechanism of triclosan resistance as well as its impact on A. baumannii. Data revealed modulated expression of the fatty acid metabolism pathway, co-factors known to play a role in the synthesis of fatty acids, as well as several transcriptional regulators. The membrane composition of the mutant revealed a decrease in C18 with a corresponding increase in C16 fatty acids compared with the parent strain A. baumannii ATCC 17978. These data indicate that A. baumannii responds to triclosan by altering the expression of genes involved in fatty acid metabolism, antibiotic resistance and amino acid metabolism.

Characteristics of road traffic accident casualties admitted to a tertiary care hospital in Sri Lanka.

The mortality and morbidity of road traffic accidents (RTA) is increasing in the South Asian region, including Sri Lanka. Therefore, the demographic factors, types of vehicles involved, and the severity of injuries sustained in RTA was studied. Age, gender, and details of the incident of all patients admitted to hospital following a RTA, between January 2007 and August 2012, were obtained by interview. Following a medico-legal examination, the type and severity of injuries was categorized as, non-grievous, grievous, endangering life or fatal in the ordinary course of nature. Of the 579 RTA casualties examined, 72% were males, 28% females, and 26% were in the 20-29 year age group. There were 44% passengers, 32% drivers, and 20% pedestrians. Of the 440 vehicle occupants, 37% were on motor cycles, 28% in three wheelers, 13% in dual purpose vehicles and 11% in buses. Of the 114 pedestrians, 33% had been struck by motor cycles, 19% by three-wheelers and 17% by dual purpose vehicles. There was at least one soft tissue injury in 84%, whilst 45% had one or more fractures. In 85% of bicycle riders, the injuries were grievous, endangering life or fatal in the ordinary course of nature. A high proportion of young adults sustained grievous injuries due to RTA. Almost two thirds of the casualties resulted from motorcycle or three wheeler accidents. Laws limiting the number of passengers carried, installation of side doors, mandatory use of seat belts in three wheelers, and protective garments for motorcyclists are recommended.