Identification of novel mazEF/pemIK family toxin-antitoxin loci and their distribution in the Staphylococcus genus

Abstract The versatile roles of toxin-antitoxin (TA) systems in bacterial physiology and pathogenesis have been investigated for more than three decades. Diverse TA loci in Bacteria and Archaea have been identified in genome-wide studies. The advent of massive parallel sequencing has substantially expanded the number of known bacterial genomic sequences over the last 5 years. In staphylococci, this has translated into an impressive increase from a few tens to a several thousands of available genomes, which has allowed us for the re-evalution of prior conclusions. In this study, we analysed the distribution of mazEF/pemIK family TA system operons in available staphylococcal genomes and their prevalence in mobile genetic elements. 10 novel m azEF/pemIK homologues were identified, each with a corresponding toxin that plays a potentially different and undetermined physiological role. A detailed characterisation of these TA systems would be exceptionally useful. Of particular interest are those associated with an SCCmec mobile genetic element (responsible for multidrug resistance transmission) or representing the joint horizontal transfer of TA systems and determinants of vancomycin resistance from enterococci. The involvement of TA systems in maintaining mobile genetic elements and the associations between novel mazEF/pemIK loci and those which carry drug resistance genes highlight their potential medical importance

Joint genomic and proteomic analysis identifies meta-trait characteristics of virulent and non-virulent Staphylococcus aureus strains

Staphylococcus aureus is an opportunistic pathogen of humans and warm-blooded animals and presents a growing threat in terms of multi-drug resistance. Despite numerous studies, the basis of staphylococcal virulence and switching between commensal and pathogenic phenotypes is not fully understood. Using genomics, we show here that S. aureus strains exhibiting virulent (VIR) and non-virulent (NVIR) phenotypes in a chicken embryo infection model genetically fall into two separate groups, with the VIR group being much more cohesive than the NVIR group. Significantly, the genes encoding known staphylococcal virulence factors, such as clumping factors, are either found in different allelic variants in the genomes of NVIR strains (compared to VIR strains) or are inactive pseudogenes. Moreover, the pyruvate carboxylase and gamma-aminobutyrate permease genes, which were previously linked with virulence, are pseudogenized in NVIR strain ch22. Further, we use comprehensive proteomics tools to characterize strains that show opposing phenotypes in a chicken embryo virulence model. VIR strain CH21 had an elevated level of diapolycopene oxygenase involved in staphyloxanthin production (protection against free radicals) and expressed a higher level of immunoglobulin-binding protein Sbi on its surface compared to NVIR strain ch22. Furthermore, joint genomic and proteomic approaches linked the elevated production of superoxide dismutase and DNA-binding protein by NVIR strain ch22 with gene duplications

Prevalence of Antibiotic and Heavy Metal Resistance Determinants and Virulence-Related Genetic Elements in Plasmids of Staphylococcus aureus

The use of antibiotics on a mass scale, particularly in farming, and their release into the environment has led to a rapid emergence of resistant bacteria. Once emerged, resistance determinants are spread by horizontal gene transfer among strains of the same as well as disparate bacterial species. Their accumulation in free-living as well as livestock and community-associated strains results in the widespread multiple-drug resistance among clinically relevant species posing an increasingly pressing problem in healthcare. One of these clinically relevant species is Staphylococcus aureus, a common cause of hospital and community outbreaks. Among the rich diversity of mobile genetic elements regularly occurring in S. aureus such as phages, pathogenicity islands, and staphylococcal cassette chromosomes, plasmids are the major mean for dissemination of resistance determinants and virulence factors. Unfortunately, a vast number of whole-genome sequencing projects does not aim for complete sequence determination, which results in a disproportionately low number of known complete plasmid sequences. To address this problem we determined complete plasmid sequences derived from 18 poultry S. aureus strains and analyzed the prevalence of antibiotic and heavy metal resistance determinants, genes of virulence factors, as well as genetic elements relevant for their maintenance. Some of the plasmids have been reported before and are being found in clinical isolates of strains typical for humans or human ones of livestock origin. This shows that livestock-associated staphylococci are a significant reservoir of resistance determinants and virulence factors. Nevertheless, nearly half of the plasmids were unknown to date. In this group we found a potentially mobilizable plasmid pPA3 being a unique example of accumulation of resistance determinants and virulence factors likely stabilized by a presence of a toxin–antitoxin system

Endoscopic surgical treatment of patients with isolated sphenoid sinus disease

Introduction. Cases of isolated lesions of the sphenoid sinus are rare. For descriptive purposes, clinicians divide them into inflammatory and non-inflammatory with prevalence of the former. Symptoms of the sphenoid sinus disease are difficult to characterise, the most common of them being vague headache and visual disturbances. Thorough preoperative evaluation of the lesion is essential – nasal endoscopy must be performed and computerised tomography or magnetic resonance imaging results analysed. The purpose of the study is to present the assessment of endoscopic surgery outcome in the own group of patients with isolated sphenoid disease. Material and methods. Clinical data of 22 subjects were analysed retrospectively. There were 5 patients with bacterial sinusitis, 6 with fungal sinusitis, 4 with allergic thickening of the mucous membrane with no evidence of bacterial or fungal infection, 2 with mucocele, 1 with sphenoid osteoma, 1 with inverted papilloma, 1 with a foreign body and 2 with cerebral fluid fistula. Each patient had preoperative nasal endoscopy and CT/MRI imaging performed. Then they underwent endoscopic transnasal sphenoethmoidectomy with removal of the lesion or closure of the fistula. The sphenoid sinus was approached through its front wall. Results. The patients’ postoperative course was uneventful. They noted improvement in all preoperative symptoms, except for bilateral oculomotor nerve paralysis in one individual, and were asymptomatic to ophthalmological examination. Conclusions. Isolated lesions of the sphenoid sinus, even very rare tumours like those presented here, can be in most cases safely approached and removed endoscopically. All risks of the method must be considered prior to the operation. High frequency of fungal sinusitis should be noted

Expression of the aldehyde oxidase 3, ent-copalyl diphosphate synthase, and VIVIPAROUS 1 genes in wheat cultivars differing in their susceptibility to pre-harvest sprouting

The quality of wheat grains is often negatively affected by pre-harvest sprouting (PHS), a complex trait with a poorly understood genetic background. In this study two wheat cultivars differing in their susceptibility to PHS were used to investigate expression of three genes: AAO3, CPS3 and VP1. AAO3 is coding for aldehyde oxidase 3, an enzyme involved in the synthesis of abscisic acid. CPS3 codes for ent-copalyl diphosphate synthase which belongs to the pathway of gibberellic acid synthesis. The product of VP1 (VIVIPAROUS 1) is a transcription factor which controls expression of the former two genes. The study was carried out using both developing and sprouting-induced grains. In Piko, a wheat cultivar susceptible to PHS, accumulation of the AAO3 transcript was significantly decreased, during the last stages of grain development, in comparison to Sława, a cultivar tolerant to PHS. In case of the CPS3 and VP1 transcripts, the differences between cultivars were especially evident from 17th to 31st day after pollination. In turn, after induction of sprouting within spikes, accumulation of the AAO3 and VP1 mRNA in the Sława grains was lower in comparison to that observed in the Piko grains. Moreover, accumulation of the CPS3 transcript was significantly higher for Piko than for Sława, both in sprouting and non-sprouting grains. According to our knowledge this report provides the first description of the AAO3 and CPS3 expression in the context of PHS, and in the future it would be valuable to correlate this information with the data on the accumulation of ABA and GA3

Endoskopowe leczenie chorych z kostniakami zatok przynosowych – doświadczenie własne

Osteomas are relatively common, benign, slow-growing, often asymptomatic neoplasms of the paranasal sinuses, occurring mainly in frontal and ethmoid sinuses. Surgical removal is done if they extend beyond the boundaries of the sinus, keep enlarging, are localised in the region adjacent to the nasofrontal duct, or if signs of chronic sinusitis are present and, irrespective of their size, in symptomatic tumours. Progressive headaches and chronic inflammation of the adjacent mucous membrane are most common symptoms. Endoscopic surgery plays an important role in management of ethmoid, sphenoid and frontal osteomas. Aim. The aim of the paper was to report own experience in endoscopic treatment of patients with osteomas of the paranasal sinuses. Material and methods. 6 patients with osteomas of paranasal sinuses were included in the group, mean age 36 years (range 15–52). Most common involvement was ethmoid cells (3). There were also patients with frontal, maxillary and sphenoid osteoma. All tumours were removed under endoscopic giudance. Frontoethmoidectomy was performed to remove ethmoid and frontal osteomas. Antrotomy was used in case of maxillary involvement and sphenoethmoidectomy in the patient with sphenoid sinus osteoma. Sphenoid sinus was approached through its anterior wall with a Stammberger punch. All the tumours were removed using fine forceps. Results. No post-operative complications were observed. No recurrences were noted. All patients remain asymptomatic. Conclusions. Resection of small and medium size osteomas of the paranasal sinuses can be safely and radically performed using endoscopic techniques. It allows their radical resection and very good cosmetic effects

Endoscopic management of osteomas of the paranasal sinuses : own experience

Osteomas are relatively common, benign, slow-growing, often asymptomatic neoplasms of the paranasal sinuses, occurring mainly in frontal and ethmoid sinuses. Surgical removal is done if they extend beyond the boundaries of the sinus, keep enlarging, are localised in the region adjacent to the nasofrontal duct, or if signs of chronic sinusitis are present and, irrespective of their size, in symptomatic tumours. Progressive headaches and chronic inflammation of the adjacent mucous membrane are most common symptoms. Endoscopic surgery plays an important role in management of ethmoid, sphenoid and frontal osteomas. Aim. The aim of the paper was to report own experience in endoscopic treatment of patients with osteomas of the paranasal sinuses. Material and methods. 6 patients with osteomas of paranasal sinuses were included in the group, mean age 36 years (range 15–52). Most common involvement was ethmoid cells (3). There were also patients with frontal, maxillary and sphenoid osteoma. All tumours were removed under endoscopic giudance. Frontoethmoidectomy was performed to remove ethmoid and frontal osteomas. Antrotomy was used in case of maxillary involvement and sphenoethmoidectomy in the patient with sphenoid sinus osteoma. Sphenoid sinus was approached through its anterior wall with a Stammberger punch. All the tumours were removed using fine forceps. Results. No post-operative complications were observed. No recurrences were noted. All patients remain asymptomatic. Conclusions. Resection of small and medium size osteomas of the paranasal sinuses can be safely and radically performed using endoscopic techniques. It allows their radical resection and very good cosmetic effects

Endoskopowe leczenie chorych z izolowanymi stanami patologicznymi zatoki klinowej

Introduction. Cases of isolated lesions of the sphenoid sinus are rare. For descriptive purposes, clinicians divide them into inflammatory and non-inflammatory with prevalence of the former. Symptoms of the sphenoid sinus disease are difficult to characterise, the most common of them being vague headache and visual disturbances. Thorough preoperative evaluation of the lesion is essential – nasal endoscopy must be performed and computerised tomography or magnetic resonance imaging results analysed. The purpose of the study is to present the assessment of endoscopic surgery outcome in the own group of patients with isolated sphenoid disease. Material and methods. Clinical data of 22 subjects were analysed retrospectively. There were 5 patients with bacterial sinusitis, 6 with fungal sinusitis, 4 with allergic thickening of the mucous membrane with no evidence of bacterial or fungal infection, 2 with mucocele, 1 with sphenoid osteoma, 1 with inverted papilloma, 1 with a foreign body and 2 with cerebral fluid fistula. Each patient had preoperative nasal endoscopy and CT/MRI imaging performed. Then they underwent endoscopic transnasal sphenoethmoidectomy with removal of the lesion or closure of the fistula. The sphenoid sinus was approached through its front wall. Results. The patients’ postoperative course was uneventful. They noted improvement in all preoperative symptoms, except for bilateral oculomotor nerve paralysis in one individual, and were asymptomatic to ophthalmological examination. Conclusions. Isolated lesions of the sphenoid sinus, even very rare tumours like those presented here, can be in most cases safely approached and removed endoscopically. All risks of the method must be considered prior to the operation. High frequency of fungal sinusitis should be noted