Virulence Properties Research Articles

In Vitro and In Silico Screening of Anti-Vibrio spp., Antibiofilm, Antioxidant and Anti-Quorum Sensing Activities of Cuminum cyminum L. Volatile Oil.

Cuminum cyminum L. essential oil (cumin EO) was studied for its chemical composition, antioxidant and vibriocidal activities. Inhibition of biofilm formation and secretion of some virulence properties controlled by the quorum sensing system in Chromobacterium violaceum and Pseudomonas aeruginosa strains were also reported. The obtained results showed that cuminaldehyde (44.2%) was the dominant compound followed by β-pinene (15.1%), γ-terpinene (14.4%), and p-cymene (14.2%). Using the disc diffusion assay, cumin EO (10 mg/disc) was particularly active against all fifteen Vibrio species, and the highest diameter of growth inhibition zone was recorded against Vibrio fluvialis (41.33 ± 1.15 mm), Vibrio parahaemolyticus (39.67 ± 0.58 mm), and Vibrio natrigens (36.67 ± 0.58 mm). At low concentration (MICs value from 0.023–0.046 mg/mL), cumin EO inhibited the growth of all Vibrio strains, and concentrations as low as 1.5 mg/mL were necessary to kill them (MBCs values from 1.5–12 mg/mL). Using four antioxidant assays, cumin EO exhibited a good result as compared to standard molecules (DPPH = 8 ± 0.54 mg/mL; reducing power = 3.5 ± 0.38 mg/mL; β-carotene = 3.8 ± 0.34 mg/mL; chelating power = 8.4 ± 0.14 mg/mL). More interestingly, at 2x MIC value, cumin EO inhibited the formation of biofilm by Vibrio alginolyticus (9.96 ± 1%), V. parahaemolyticus (15.45 ± 0.7%), Vibrio cholerae (14.9 ± 0.4%), and Vibrio vulnificus (18.14 ± 0.3%). In addition, cumin EO and cuminaldehyde inhibited the production of violacein on Lauria Bertani medium (19 mm and 35 mm, respectively). Meanwhile, 50% of violacein inhibition concentration (VIC50%) was about 2.746 mg/mL for cumin EO and 1.676 mg/mL for cuminaldehyde. Moreover, elastase and protease production and flagellar motility in P. aeruginosa were inhibited at low concentrations of cumin EO and cuminaldehyde. The adopted in-silico approach revealed good ADMET properties as well as a high binding score of the main compounds with target proteins (1JIJ, 2UV0, 1HD2, and 3QP1). Overall, the obtained results highlighted the effectiveness of cumin EO to prevent spoilage with Vibrio species and to interfere with the quorum sensing system in Gram-negative bacteria by inhibiting the flagellar motility, formation of biofilm, and the secretion of some virulence enzymes.

Exploration of Streptococcus core genome to reveal druggable targets and novel therapeutics against S. pneumoniae.

Streptococcus pneumoniae (S. pneumoniae), the major etiological agent of community-acquired pneumonia (CAP) contributes significantly to the global burden of infectious diseases which is getting resistant day by day. Nearly 30% of the S. pneumoniae genomes encode hypothetical proteins (HPs), and better understandings of these HPs in virulence and pathogenicity plausibly decipher new treatments. Some of the HPs are present across many Streptococcus species, systematic assessment of these unexplored HPs will disclose prospective drug targets. In this study, through a stringent bioinformatics analysis of the core genome and proteome of S. pneumoniae PCS8235, we identified and analyzed 28 HPs that are common in many Streptococcus species and might have a potential role in the virulence or pathogenesis of the bacteria. Functional annotations of the proteins were conducted based on the physicochemical properties, subcellular localization, virulence prediction, protein-protein interactions, and identification of essential genes, to find potentially druggable proteins among 28 HPs. The majority of the HPs are involved in bacterial transcription and translation. Besides, some of them were homologs of enzymes, binding proteins, transporters, and regulators. Protein-protein interactions revealed HP PCS8235_RS05845 made the highest interactions with other HPs and also has TRP structural motif along with virulent and pathogenic properties indicating it has critical cellular functions and might go under unconventional protein secretions. The second highest interacting protein HP PCS8235_RS02595 interacts with the Regulator of chromosomal segregation (RocS) which participates in chromosome segregation and nucleoid protection in S. pneumoniae. In this interacting network, 54% of protein members have virulent properties and 40% contain pathogenic properties. Among them, most of these proteins circulate in the cytoplasmic area and have hydrophilic properties. Finally, molecular docking and dynamics simulation demonstrated that the antimalarial drug Artenimol can act as a drug repurposing candidate against HP PCS8235_RS 04650 of S. pneumoniae. Hence, the present study could aid in drugs against S. pneumoniae.

Virulence genes, phylogenetic analysis, and antimicrobial resistance of Escherichia coli isolated from urinary tract infection in hospitalized patients and outpatients.

Uropathogenic Escherichia coli (UPEC) strains are the most common cause of urinary tract infection (UTI) in hospitalized and community patients. The aim was to compare the genetic characteristics of E. coli isolated from inpatients (IPs) and outpatients (OPs) with UTI regarding their phylogenies, virulence traits, and resistance trends. In this cross-sectional study, 130 epidemiologically unrelated E. coli isolates were collected from patients with UTI. Extended-spectrum beta-lactamase (ESBL) production was detected by the combination disk method. UPEC and intestinal pathogenic E. coli (IPEC) virulence genes were detected by polymerase chain reaction. The isolates were analyzed for phylogenetic grouping. A P value of < 0.05 was considered significant. Of the 130 isolates, 62.3% were from OPs and 37.7% from IPs. About 35.8% of the OPs and 49% of the IPs were ESBL positive. Moreover, 56.8% of the OPs and 59.2% of the IPs were positive for UPEC virulence genes. Notably, 50% of the isolates from each group exhibited IPEC virulence properties. The predominant phylogroup was B2 (43.2% in the OPs and 40.8% in the IPs). No significant difference was found between the IP and OP isolates (P > 0.05). Our results may indicate that consideration should also be given to hygienic standards in the community. The marked genetic plasticity of E. coli has allowed the emergence of strains showing arrays of genes from different pathotypes. Characterization of E. coli isolates in different areas may guide the selection of effective infection control strategies.

Virulence factors of Malassezia strains isolated from pityriasis versicolor patients and healthy individuals.

There is still little information on the virulence factors of Malassezia spp., despite their implication in severe diseases. Phospholipase, lipase, and hemolytic activities, biofilm formation and decreased antifungal susceptibility seem to contribute to their virulence in susceptible hosts.

Draft-genome analysis provides insights into the virulence properties and genome plasticity of Vibrio fluvialis organisms isolated from shrimp farms and Turag river in Bangladesh.

Vibrio fluvialis is an opportunistic waterborne and seafood-borne enteric pathogen capable of causing severe diarrhea leading to death. This pathogen is endemic to Bangladesh, a country which is a major producer of cultured shrimp and wild-caught prawns. In this study, we carried out whole-genome sequencing of three V. fluvialis organisms isolated from shrimp farm and river sediment showing strong pathogenic characteristics in vivo and in vitro and compared their genomes against other V. fluvialis and related pathogenic species to glean insights into their potential as pathogens. Numerous virulence-associated genes including hemolysins, cytolysins, three separate Type IV pili, Types II and VI secretion systems, biofilm, and the V. cholerae pathogenesis regulating gene, toxR, were identified. Moreover, we found strain S-10 to have the propensity to acquire antibiotic resistance genes through horizontal gene transfer. These findings indicate that shrimp farms and rivers could be potential sources of V. fluvialis organisms which are an infection threat of public health concern.

Salmonella enterica Serovar Typhimurium and Enteritidis Isolated from Raw Shrimp in Bangladesh: An Investigation Based on Molecular Characteristics, Survival, Virulence, Antibiotic Resistance, and Biofilm Formation Attributes

Shrimp is the white gold of Bangladesh, with the second-highest income source from exporting to foreign countries. Contamination with Salmonella spp. is now one of the significant issues for Bangladesh to export. Proper characterization of the salmonella pathogen is thus necessary to avoid undesirable losses due to the rejection of exported shrimp. In Bangladesh, the present condition of raw shrimp contamination with pathogenic Salmonella serovars and their survival/virulence properties was not adequately characterized. In this study, we collected 43 raw shrimps as samples from different farms in Jashore, Khulna, and Sathkhira regions. We then maintained standard cultural and biochemical protocols for isolating Salmonella strains, followed by the molecular identification of particular Salmonella serovars. The standard method for checking its credibility to form biofilm in 0–10% NaCl, tolerate acid/bile stress likewise in the gastrointestinal tract, and resist antimicrobial pressure was performed individually with the particular pathogenic strains. Our results successfully identified eleven Salmonella strains with three typhimurium serovars and three enteritidis serovars, which have biofilm-forming capability up to 4–8% NaCl, acid/bile habituation alike stomach/small intestine of humans, and resistance against necessary antibiotics generally used in treating human and poultry infection signifying the impending danger in the shrimp industry. While previous studies of Bangladesh successfully isolated Salmonella only presumptively, our research focused mainly on molecular characterization of the human Salmonella pathogen along with important survival and virulent attributes, such as biofilm formation, acid/bile tolerance, and antibiotic resistance of selected S. typhimurium and S. enteritidis strains. Further study with more sampling will be necessary to confer the transmission route of the pathogen from the natural reservoir to the shrimp industry.

Quorum Quenching-Guided Inhibition of Mixed Bacterial Biofilms and Virulence Properties by Protein Derived From Leaves of Carissa carandas.

The inhibition/degradation potential of Carissa carandas proteinaceous leaf extract against mixed bacterial biofilm of Staphylococcus aureus MTCC 96, Escherichia coli MTCC 1304, Pseudomonas aeruginosa MTCC 741, and Klebsiella pneumoniae MTCC 109, responsible for nosocomial infections, was evaluated. Distinct inhibition/degradation of mixed bacterial biofilm by the proteinaceous leaf extract of C. carandas was observed under a microscope, and it was found to be 80%. For mono-species biofilm, the maximum degradation of 70% was observed against S. aureus biofilm. The efficiency of aqueous plant extracts to inhibit the mono-species biofilm was observed in terms of minimum inhibitory concentration (MIC), and the best was found against P. aeruginosa (12.5 μg/ml). The presence of flavonoids, phenols, and tannins in the phytochemical analysis of the plant extract suggests the main reason for the antibiofilm property of C. carandas. From the aqueous extract, protein fraction was precipitated using 70% ammonium sulfate and dialyzed. This fraction was purified by ion-exchange chromatography and found to be stable and active at 10°C (pH 7). The purified fraction showed less than 40% cytotoxicity, which suggests that it can be explored for therapeutic purposes after in-depth testing. In order to investigate the mechanistic action of the biofilm inhibition, the plant protein was tested against Chromobacterium violaceum CV026, and its inhibitory effect confirmed its quorum quenching nature. Based on these experimental analyses, it can be speculated that the isolated plant protein might influence the signaling molecule that leads to the inhibition effect of the mixed bacterial biofilm. Further experimental studies are warranted to validate our current findings.

Knockout of mlaA increases Escherichia coli virulence in a silkworm infection model.

The mlaA gene encodes a lipoprotein to maintain an outer membrane lipid asymmetry in gram-negative bacteria. Although the role of mlaA in bacterial virulence has been studied in several bacterial species, there are no reports of its role in E. coli virulence. In this study, we found that knockout of mlaA in E. coli increased its virulence against silkworms. The mlaA-knockout mutant was sensitive to several antibiotics and detergents, but resistant to vancomycin and chlorhexidine. The mlaA-knockout mutant grew faster than the parent strain in the presence of silkworm hemolymph. The mlaA-knockout mutant also produced a larger amount of outer membrane vesicles than the parent strain. These findings suggest that mlaA knockout causes E. coli resistance to specific antimicrobial substances and increases outer membrane vesicle production, thereby enhancing E. coli virulence properties in the silkworm infection model.

Primary mycoses and virulence of dimorphous particularly dangerous micromycetes

Mycotic infections are traditionally considered to be markers of immunodeficiency, however, primary mycoses develop even in immunocompetent individuals. Etiological agents of primary mycoses, which, according to the nomenclature adopted in the Russian Federation, are classified as particularly dangerous, are micromycetes of group II pathogenicity of the genera Coccidioides, Histoplasma, Paracoccidioides, Blastomyces. Particularly dangerous mycoses are common in certain geographical areas of the world: coccidioidomycosis occurs in semi-desert regions, histoplasmosis and paracoccidioidomycosis – in tropical areas, and blastomycosis – in temperate climate regions. However, despite the endemic nature of these diseases, they remain important both for European countries and the Russian Federation for a number of reasons, sporadic cases of particularly dangerous mycoses are regularly recorded in many European countries. It has been shown that several genetically determined factors are important for the implementation of the virulent properties of pathogenic fungi. Thermal dimorphism is of fundamental importance as a trigger for the transformation of a pathogen from a mycelial to a tissue (parasitic) growth phase, in which the causative agent of infection is able to fully realize its virulent properties.

Emergence and evolution of virulence in human pathogenic fungi.

One billion people worldwide are affected by fungal pathogens, of which 1.6 million succumb to fungal infections per year. This review discusses the emergence and evolution of fungal pathogenesis in humans in the form of opportunistic commensal and environmental fungi. We explore the attributes that contribute to their success as pathogens and the scenarios which may have caused the evolutionary selection of virulence factors. This includes antivirulence and avirulence genes, notions that are new for fungal pathogens of humans but which are based on well established concepts in bacterial pathogens and phytopathogenic fungi. These ideas will ultimately help us to better understand the pathogenicity of fungi that infect humans: from the emergence to the finer adjustment of virulence to promote pathogen persistence.

In Vitro Study of Irrigation solution of Chitosan Nanoparticles to Inhibit the Adhesion and Biofilm Formation of Enterococcus faecalis in the Root Canal

Enterococcus faecalis (E. faecalis) plays a role in the pathogenesis of dental root canal infections. Chitosan has antibacterial properties and a chelating agent in the tooth root canal and is biodegradable and non-toxic. They analyzed the irrigation response of Chitosan nanoparticles to the virulence properties of E. faecalis in the dental root canal. Examination of E. faecalis virulence properties was carried out with violet crystals to obtain biofilm inhibition strength, Gram staining to determine lysis and coagulation of bacterial cells, and Atomic Force Microscopy (AFM) to analyze the surface roughness of the tooth root canal. Chitosan nanoparticles combined with 2.5% NaOCl has a strong inhibition of the formation of E. faecalis biofilm, both based on the control group (p&gt; 0.05; 0.088) and incubation time of 48 h and 72 h, also inhibitory power, which was better at 24 h (p&gt; 0.05; 0.185) than the other groups. Irrigation solution of Chitosan nanoparticles combined with 2.5% NaOCl has better lysis and cell agglutination of E. faecalis bacteria compared to other groups, especially at all incubation times, based on the control group (p&gt; 0.05; 0.104) and incubation time (p&gt; 0.05; 0.580) can reduce the surface roughness of the dental root canal, but the impact of giving irrigation materials to each treatment group with the incubation time showed significant differences (p&lt;0.05). The Chitosan nanoparticles solution as an irrigation material has a strong ability to suppress the formation of biofilms, coagulation, and lysis of E. faecalis cells and better reduce the walls' surface roughness dental root canal at 24 hours incubation time.

PHYLOTYPING, PATHOTYPING and PHENOTYPIC CHARACTERISTICS of Escherichia coli ISOLATED from VARIOUS STREET FOODS in BANGLADESH

The burden of street food contamination remains significantly higher among developing countries, making its consumers' health compromised. This study aimed at identifying Escherichia coli in local street foods, track their sources and characterize their virulence properties, antimicrobial susceptibility patterns, and incidence of recent fecal contamination. Twelve E. coli isolates isolated from 28 types of street foods sold at different locations of Dhaka metropolitan city were confirmed by both culture-based and molecular methods. Phylogroup B1 of environment origin was the most predominant (58%, n=12) among the isolates, followed by commensal phylogroup A (16%), phylogroup C (8%), D (8%), and E (8%). Alarmingly, 8% of the isolates were confirmed to be Enteropathogenic E. coli (EPEC), harboring hlyA gene, and 41% were due to recent fecal contamination cases confirmed by the presence of the eae gene. Isolates showed the highest resistance to ampicillin, followed by chloramphenicol. However, resistance could not be correlated to the presence of class 1 integron as isolates sensitive to these antibiotics also harbored this mobile genetic element. The findings of this study demonstrated the presence of antibiotic-resistant, potentially pathogenic E. coli in street food which emphasizes the health hazard associated with consumption of such foods.

Phenotypic and molecular characterization of the causative agents of edwardsiellosis causing Nile tilapia (Oreochromis niloticus) summer mortalities

Edwardsiellosis is a serious bacterial disease affecting Nile tilapia (Oreochromis niloticus), causing septicemia and mortalities. Edwardsiella tarda and Edwardsiella anguillarum were isolated from Nile tilapia summer mortality events in Egypt. Diseased fish showed hemorrhagic septicemia, skin erosions, and eye opacity. A total of 24 Edwardsiella spp. isolates were retrieved from the investigated fish specimens. Phenotypic and biochemical characteristics grouped isolates into typical Ed. tarda (n = 14 strains) and atypical Ed. tarda (n = 10 strains). The BLAST analysis of sodB gene sequencing confirmed the conventional identification of typical Ed. tarda strains (n = 14) and reidentified all the atypical strains (n = 10) as Ed. anguillarum. Isolates showed a combination of virulence factors, including biofilm formation (66.6%), hemolysis (100%), chondroitinase (50%), and proteolytic activity (20.8%). The major part of isolates showed high resistance to ampicillin, amoxicillin, gentamycin antibiotics and harbored tetA, blaCTX-M, and aadA1 resistance genes. Pathogenicity testing of isolates in O. niloticus confirmed their virulence. Challenged fish exhibited septicemic signs similar to naturally diseased fish. Infections in naturally infected tilapia triggered acute and chronic histopathological alterations. Degenerative and necrotic changes were noticed in hematopoietic organs. Granulomas were noticed in between the hepatic parenchyma. The data extracted from the study confirm that accurate identification of the causative agents of edwardsiellosis should be reliant on genetic-based approaches. Analysis of the bacterium virulence properties offers insights into establishing novel therapeutics for edwardsiellosis control. The findings refer to the need for antimicrobial sensitivity testing to minimize antimicrobial resistance and increase therapy efficacy.

Identification of Antigenic Properties of Acinetobacter baumannii Proteins as Novel Putative Vaccine Candidates Using Reverse Vaccinology Approach.

Multidrug-resistant Acinetobacter baumannii (A. baumannii) infections are becoming more prevalent all over the world. As a cost-effective and preventative method, vaccination seems to be required against this bacterium. In the present study, subtractive proteomics along with reverse vaccinology approaches was used to predict suitable therapeutics against A. baumannii. Using the Vaxign online tool, we studied over 35 genomes of A. baumannii strains and chose outer membrane and secreted proteins of A. baumannii 1656-2 as possible vaccine candidates. Then, investigations were performed on the immunogenicity, antigenic characteristics, physicochemical properties, B-cell and MHC class I, and MHC class II molecules epitope densities of proteins. After optimizing the codon of the proteins, the pcDNA3.1( +) expression construct was designed and the immunogenicity, allergenicity, and physicochemical properties of the vaccine construct were predicted. Hcp and OmpC proteins were predicted as extracellular and outer membrane proteins, respectively. These proteins interact with 10 other proteins to form a network of protein interactions with virulence properties. Immunoassays of Hcp and OmpC proteins showed antigenicity of 0.88 and 0.79, respectively. These proteins have 5 structural cell epitope points and 5 linear B epitope points. They are also able to bind to different HLA alleles of MCH class I/class II as selected immunogenic proteins and designed non-allergenic structures with solubility of 0.650 and immunogenicity score of 0.91. The results of this "in silico" study indicate high specificity and the development of a significant humoral and cellular immune response. It can be concluded that the Hcp and OmpC dual vaccine construct is one of the promising candidates against A. baumannii. The findings of this "in silico" study show excellent specificity and the emergence of a substantial humoral and cellular immune response. This is a computer-based study that needs to be tested in vitro and in vivo to corroborate the conclusions of the vaccine design procedures.

Age and gender associated changes in immunoglobulin subclass levels specific to S. pneumoniae, serotype 1

S. pneumoniae is an important human pathogen which has a polysaccharide capsule with virulent properties. This work aims to estimate the titres of S. pneumoniae specific IgG and IgA isotypes, with respect to age and sex.An in-house whole bacterial cell ELISA was used for the determination of relative levels and endpoint titres of IgG subclasses and IgA1 subclass specific for S. pneumoniae serogroup 1, and to quantify specific IgG1 and IgG2 levels.Significantly lower anti-pneumococcus IgG1 titres were found in older individuals, which was more pronounced in men. Lower IgG2 titres were detected in men over 50 years of age, in comparison to women under 50 years of age. The levels of IgG3 and IgG4 did not differ between different sex and age groups. Lower IgA1 levels were detected in male individuals in both age groups in comparison to females under 50 years of age. The levels of IgG1 showed a moderate correlation with IgG4 in younger individuals of both sexes (r = 0.61 in men and 0.63 in women) which was not noted in the older age group.We highlight the deficiency in humoral immunity in older people, especially male and suggest immunization of this population with pneumococcal vaccines.

In silico functional and structural characterization revealed virulent proteins of Francisella tularensis strain SCHU4.

Francisella tularensis is a pathogenic, aerobic gram-negative coccobacillus bacterium. It is the causative agent of tularemia, a rare infectious disease that can attack skin, lungs, eyes, and lymph nodes. The genome of F. tularensis has been sequenced, and ~16% of the proteome is still uncharacterized. Characterizations of these proteins are essential to find new drug targets for better therapeutics. In silico characterization of proteins has become an extremely important approach to determine the functionality of proteins as experimental functional elucidation is unable to keep pace with the current growth of the sequence database. Initially, we have annotated 577 Hypothetical Proteins (HPs) of F. tularensis strain SCHU4 with seven bioinformatics tools which characterized them based on the family, domain and motif. Out of 577 HPs, 119 HPs were annotated by five or more tools and are further screened to predict their virulence properties, subcellular localization, transmembrane helices as well as physicochemical parameters. VirulentPred predicted 66 HPs out of 119 as virulent. These virulent proteins were annotated to find the interacting partner using STRING, and proteins with high confidence interaction scores were used to predict their 3D structures using Phyre2. The three virulent proteins Q5NH99 (phosphoserine phosphatase), Q5NG42 (Cystathionine beta-synthase) and Q5NG83 (Rrf2-type helix turn helix domain) were predicted to involve in modulation of cytoskeletal and innate immunity of host, H2S (hydrogen sulfide) based antibiotic tolerance and nitrite and iron metabolism of bacteria. The above predicted virulent proteins can serve as novel drug targets in the era of antibiotic resistance.

A RARE PRESENTATION OF TB-RELATED SEPTIC SHOCK

TYPE: Case Report TOPIC: Lung Pathology INTRODUCTION: Without treatment, tuberculosis (TB) may lead to septic shock in immunocompetent individuals. Through the interaction of lipoarabinomannan (LAM) on the mycobacterium cell wall with antigen presenting cells, TB may be able to survive in host cells for long periods of time; causing widespread lung damage and systemic disease. We report a unique case of a 24-year-old woman with an untreated mycobacterial infection who developed bronchiectasis and TB-related septic shock. CASE PRESENTATION: A 24-year-old Guyanese woman with no past medical history presented to the hospital with shortness of breath, weight loss, and hemoptysis. She was hemodynamically unstable and severely cachectic with coarse lung sounds. Imaging demonstrated diffuse interstitial opacities and large cystic changes. Fluids were given, her sputum was positive for acid fast bacilli, and she was started on R.I.P.E. treatment for tuberculosis. The patient became severely hypoxic requiring intubation. She ultimately developed refractory hypotension despite 4 different vasopressors. She became pulseless and ACLS protocol was initated, though, she remained in asystole throughout the arrest. DISCUSSION: Lipoarabinomannan, a glycolipid on the mycobacterium cell wall with virulent properties, directly activates SHP-1 through phosphorylation. SHP-1, a signaling molecule which regulates many different cellular processes, may deactivate proinflammatory cytokines and inhibit INF-y release. This inability to activate macrophages promotes intracellular survival of TB in host cells. This mechanism may account for diffuse bronchiectasis and a systemic inflammatory response, as in our patient. CONCLUSIONS: This case highlights the possibility of tuberculosis-related septic shock in the critical care setting and draws attention to mechanisms of pathogenesis if left untreated. DISCLOSURE: Nothing to declare. KEYWORD: septic shock

Genomic Approaches to Antifungal Drug Target Identification and Validation.

The last several decades have witnessed a surge in drug-resistant fungal infections that pose a serious threat to human health. While there is a limited arsenal of drugs that can be used to treat systemic infections, scientific advances have provided renewed optimism for the discovery of novel antifungals. The development of chemical-genomic assays using Saccharomyces cerevisiae has provided powerful methods to identify the mechanism of action of molecules in a living cell. Advances in molecular biology techniques have enabled complementary assays to be developed in fungal pathogens, including Candida albicans and Cryptococcus neoformans. These approaches enable the identification of target genes for drug candidates, as well as genes involved in buffering drug target pathways. Here, we examine yeast chemical-genomic assays and highlight how such resources can be utilized to predict the mechanisms of action of compounds, to study virulence attributes of diverse fungal pathogens, and to bolster the antifungal pipeline.

Genomic Clues of a Multidrug-Resistant Bacterium from Cultured Domestic Silkworm (Bombyx mori L.).

ABSTRACTEnterobacter sp. strain ASE was isolated from the gut of an infected domestic silkworm (Bombyx mori L.; Lepidoptera: Bombycidae). The whole-genome sequence (WGS) of the multidrug-resistant strain Enterobacter sp. ASE, which may contribute to our understanding of the strain’s antibiotic resistance mechanism and virulence properties.

Diarrhoeagenic E. coli occurrence and antimicrobial resistance of Extended Spectrum Beta-Lactamases isolated from diarrhoea patients attending health facilities in Accra, Ghana.

IntroductionDiarrhoea accounts for high morbidity and mortality in children and adults worldwide. Extended Spectrum Beta-Lactamase-Producing Enterobacteriaceae (ESBL-PE) and Diarrhoeagenic Escherichia coli (DEC) contribute to prolonged hospitalization because of their resistance and virulence properties aiding in the spread of diarrhoeal disease and delayed treatment.AimTo determine DEC and the antimicrobial resistance of ESBL-PE isolated among diarrhoea patients attending two health facilities in Ghana.MethodsStool samples were collected from 122 diarrhoeal patients who attended Maamobi General Hospital and Kaneshie Polyclinic between January 2019 and March 2020. Identification of bacteria was performed by using the Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). Using disk diffusion, antimicrobial susceptibility testing (AST) was conducted and interpreted according to the 2018 CLSI guidelines. Detection of ESBL and DEC genes was performed using Polymerase chain reaction (PCR).ResultsA total of 80.3% (98/122) Enterobacteriaceae was recovered from the patients in the study with an overall ESBL occurrence of 20.4% (20/98), predominantly among E. coli showed 13.2% (10/76), Klebsiella pneumoniae,35.7%(5/14) and Proteus mirabilis, 57.1%(4/7). Among the ESBL genes detected, blaTEM (n = 14) was common, followed by blaCTX-M (n = 13) and blaSHV (n = 4). Thirty-four E. coli isolates possessed the heat labile (Lt) gene of Enterotoxigenic E. coli (ETEC).ConclusionOur findings confirm the existence of DEC and the antimicrobial resistance patterns of ESBL-PE among stool isolates, limiting the options of commonly used drugs for diarrhoeal treatment in Ghana. Routine laboratory testing in health care facilities and strengthened surveillance systems among hospital networks are encouraged for a better understanding of their epidemiology and clinical implications.