scholarly journals Infective endocarditis caused by Cardiobacterium valvarum

2019 ◽  
Vol 1 (8) ◽  
Author(s):  
Yohei Washio ◽  
Shun-ichiro Sakamoto ◽  
Ryoichi Saito ◽  
Takahito Nei ◽  
Masayo Morishima ◽  
...  
Keyword(s):  
Infective Endocarditis ◽  
Ribosomal Rna ◽  
Transthoracic Echocardiography ◽  
Type Species ◽  
Blood Cultures ◽  
Gram Negative ◽  
Content Type ◽  
Link Type ◽  
Conventional Methods ◽  
Positive Results

We report a case with infective endocarditis (IE) due to Cardiobacterium valvarum . The patient was a 57-year-old male, who was referred to our hospital based on suspected IE detected by transthoracic echocardiography at a neighbourhood clinic. Three sets of blood cultures obtained on admission yielded positive results, and revealed rather slender and linear Gram-negative bacilli with a rosette formation that dyed minimally, with a pale white appearance. Although no isolates were identified by conventional methods, C. valvarum was ultimately identified by 16 S ribosomal RNA genotyping. HACEK group strains are difficult to identify by conventional methods. Therefore, if Gram-negative bacilli are isolated from IE patients, 16 S ribosomal RNA genotyping will be necessary. Furthermore, IE due to C. valvarum is very rare. We thus discuss our case in comparison with previous reports.

scholarly journals Rare case report of infective endocarditis due to Kocuria kristinae in a patient with ventricular septal defect

2020 ◽  
Vol 2 (1) ◽  
Author(s):  
Arif Maqsood Ali ◽  
Gule Raana Waseem ◽  
Shazia Arif
Keyword(s):  
Congenital Heart Disease ◽  
Heart Disease ◽  
Infective Endocarditis ◽  
Type Species ◽  
Rare Case ◽  
Congenital Heart ◽  
Septal Defect ◽  
Blood Cultures ◽  
Content Type ◽  
Link Type

Background. Infective endocarditis (IE) is an uncommon but life-threatening infection. It is commonly associated with diseased or damaged valves. Patients with congenital heart disease are more prone to getting IE than the general population. The typical organisms that cause IE include Staphylococcus , Coagulase-negative Staphylococcus, Streptococcus viridians and Enterococci. However, the importance of rare micro-organisms like Kocuria kristinae should not be underestimated especially when isolated from multiple blood cultures in patients suspected of IE. Case presentation. We report a rare case of right-sided infective endocarditis due to K. kristinae in a young non-diabetic, non-addict female of low socioeconomic class who presented with undiagnosed fever for 1 year. She was investigated and treated for fever by several general practitioners without relief. Later on, she was diagnosed by a local cardiologist to have perimembranous ventricular septal defect with a small pulmonary valve vegetation. She was referred to a tertiary care cardiac hospital in Rawalpindi, Pakistan for further management. Transthoracic and transesophageal echocardiography confirmed IE secondary to preexisting congenital heart disease complicated with a small pulmonary vegetation. Her blood cultures yielded growth of K. kristanae, a rare micro-organism to cause IE. The patient responded to the antibiotic therapy. Conclusion. Clinicians should have a high index of suspicion for K. kristanae IE as a possible cause of a prolonged fever especially in the presence of congenital heart disease. Antibiotic susceptibility is required for adequate therapy.

scholarly journals In vitro synergy of 5-nitrofurans, vancomycin and sodium deoxycholate against Gram-negative pathogens

2021 ◽  
Author(s):  
Catrina Olivera ◽  
Vuong Van Hung Le ◽  
Catherine Davenport ◽  
Jasna Rakonjac
Keyword(s):  
Growth Inhibition ◽  
Type Species ◽  
Sodium Deoxycholate ◽  
Gram Positive ◽  
Bacterial Killing ◽  
Gram Negative ◽  
Content Type ◽  
Link Type ◽  
Time Kill

Introduction. There is an urgent need for effective therapies against bacterial infections, especially those caused by antibiotic-resistant Gram-negative pathogens. Hypothesis. Synergistic combinations of existing antimicrobials show promise due to their enhanced efficacies and reduced dosages which can mitigate adverse effects, and therefore can be used as potential antibacterial therapy. Aim. In this study, we sought to characterize the in vitro interaction of 5-nitrofurans, vancomycin and sodium deoxycholate (NVD) against pathogenic bacteria. Methodology. The synergy of the NVD combination was investigated in terms of growth inhibition and bacterial killing using checkerboard and time-kill assays, respectively. Results. Using a three-dimensional checkerboard assay, we showed that 5-nitrofurans, sodium deoxycholate and vancomycin interact synergistically in the growth inhibition of 15 out of 20 Gram-negative strains tested, including clinically significant pathogens such as carbapenemase-producing Escherichia coli , Klebsiella pneumoniae and Acinetobacter baumannii , and interact indifferently against the Gram-positive strains tested. The time-kill assay further confirmed that the triple combination was bactericidal in a synergistic manner. Conclusion. This study demonstrates the synergistic effect of 5-nitrofurans, sodium deoxycholate and vancomycin against Gram-negative pathogens and highlights the potential of the combination as a treatment for Gram-negative and Gram-positive infections.

scholarly journals Loss of the virulence plasmid by Shigella sonnei promotes its interactions with CD207 and CD209 receptors

2021 ◽  
Vol 70 (3) ◽  
Author(s):  
Bi-cong Wu ◽  
Njiri A. Olivia ◽  
John Mambwe Tembo ◽  
Ying-xia He ◽  
Ying-miao Zhang ◽  
...  
Keyword(s):  
Type Species ◽  
Shigella Sonnei ◽  
Virulence Plasmid ◽  
Gram Negative Bacteria ◽  
Lectin Receptors ◽  
Gram Negative ◽  
Content Type ◽  
Link Type ◽  
O Antigen ◽  
Rough Strain

Introduction. Shigella sonnei, the cause of bacillary dysentery, belongs to Gram-negative enteropathogenic bacteria. S. sonnei contains a 210 kb virulence plasmid that encodes an O-antigen gene cluster of LPSs. However, this virulence plasmid is frequently lost during replication. It is well-documented that after losing the O-antigen and becoming rough strains, the Gram-negative bacteria may express an LPS core on its surface. Previous studies have suggested that by using the LPS core, Gram-negative bacteria can interact with several C-type lectin receptors that are expressed on antigen-presenting cells (APCs). Hypothesis/Gap Statement. S. sonnei by losing the virulence plasmid may hijack APCs via the interactions of LPS-CD209/CD207. Aim. This study aimed to investigate if the S. sonnei rough strain, by losing the virulence plasmid, interacted with APCs that express C-type lectins of human CD207, human CD209a and mouse CD209b. Methodology. SDS-PAGE silver staining was used to examine the O-antigen expression of S. sonnei WT and its rough strain. Invasion assays and inhibition assays were used to examine the ability of S. sonnei WT and its rough strain to invade APCs and investigate whether CD209 and CD207 are receptors for phagocytosis of rough S. sonnei . Animal assays were used to observe the dissemination of S. sonnei . Results. S. sonnei did not express O-antigens after losing the virulence plasmid. The S. sonnei rough strain invades with APCs, including human dendritic cells (DCs) and mouse macrophages. CD209 and CD207 are receptors for phagocytosis of rough S. sonnei . Expression of the O-antigen reduces the ability of the S. sonnei rough strain to be disseminated to mesenteric lymph nodes and spleens. Conclusion. This work demonstrated that S. sonnei rough strains – by losing the virulence plasmid – invaded APCs through interactions with CD209 and CD207 receptors.

Arenimonas daechungensis sp. nov., isolated from the sediment of a eutrophic reservoir

2013 ◽  
Vol 63 (Pt_2) ◽  
pp. 484-489 ◽  
Author(s):  
Hangsak Huy ◽  
Long Jin ◽  
Young-Ki Lee ◽  
Keun Chul Lee ◽  
Jung-Sook Lee ◽  
...  
Keyword(s):  
Dna Hybridization ◽  
Type Strain ◽  
Type Species ◽  
Novel Species ◽  
Genetic Data ◽  
Rrna Gene ◽  
16S Rrna Gene Sequences ◽  
Gram Negative ◽  
Content Type ◽  
Link Type

A Gram-negative, non-motile, non-spore-forming and rod-shaped bacterial strain, CH15-1T, was isolated from a sediment sample taken from Daechung Reservoir, South Korea, during the late-blooming period of cyanobacteria. Strain CH15-1T grew optimally at pH 7.0 and 30 °C. A phylogenetic analysis based on 16S rRNA gene sequences confirmed that strain CH15-1T belongs to the genus Arenimonas with the similarity range from 92.6–97.4 % and is closely related to Arenimonas oryziterrae YC6267T (97.4 %), Arenimonas composti TR7-09T (95.4 %), Arenimonas metalli CF5-1T (94.7 %), Arenimonas malthae CC-JY-1T (94.6 %) and Arenimonas donghaensis HO3-R19T (92.6 %). However, the DNA–DNA hybridization between strain CH15-1T and the closest strain, Arenimonas oryziterrae YC6267T, was 8.9–12.9 %. The DNA G+C content was 63.9 mol% compared to A. oryziterrae YC626T, 65.8 mol%. Strain CH15-1T included Q-8 as the major ubiquinone and phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol and phosphatidylmonomethylethanolamine as the major polar lipids. The major fatty acids (>5 %) were iso-C15 : 0, iso-C16 : 0, iso-C14 : 0, iso-C11 : 0 3-OH, iso-C17 : 0 and summed feature 9 (iso-C17 : 1ω9c and/or C16 : 0 10-methyl). On the basis of phylogenetic, phenotypic and genetic data, strain CH15-1T was classified in the genus Arenimonas as a member of a novel species, for which the name Arenimonas daechungensis sp. nov. is proposed. The type strain is CH15-1T ( = KCTC 23553T = DSM 24763T).

scholarly journals Veillonella nakazawae sp. nov., an anaerobic Gram-negative coccus isolated from the oral cavity of Japanese children

2020 ◽  
Author(s):  
Izumi Mashima ◽  
Citra F. Theodorea ◽  
Ariadna A. Djais ◽  
Tadao Kunihiro ◽  
Yoshiaki Kawamura ◽  
...  
Keyword(s):  
16S Rrna ◽  
Oral Cavity ◽  
Related Species ◽  
Type Strain ◽  
Type Species ◽  
Japanese Children ◽  
Closely Related Species ◽  
Gram Negative ◽  
Content Type ◽  
Link Type

Two strains of previously unknown Gram-negative cocci, T1-7T and S6-16, were isolated from the oral cavity of healthy Japanese children. The two strains showed atypical phenotypic characteristics of members of the genus Veillonella , including catalase production. Sequencing of their 16S rRNA genes confirmed that they belong to genus Veillonella . Under anaerobic conditions, the two strains produced acetic acid and propionic acid as metabolic end-products in a trypticase–yeast extract–haemin medium containing 1 % (w/v) glucose, 1 % (w/v) fructose and 1 % (v/v) sodium lactate. Comparative analysis of the 16S rRNA, dnaK, rpoB and gltA gene sequences revealed that the two strains are phylogenetically homogeneous and comprise a distinct, novel lineage within the genus Veillonella . The sequences from the two strains shared the highest similarity, at 99.9, 95.8, 96.9 and 96.7 %, using the partial 16S rRNA, dnaK, rpoB and gltA gene sequences, respectively, with the type strains of the two most closely related species, Veillonella dispar ATCC 17748T and Veillonella infantium JCM 31738T. Furthermore, strain T1-7T shared the highest average nucleotide identity (ANI) value (94.06 %) with type strain of the most closely related species, V. infantium . At the same time, strain T1-7T showed the highest digital DNA–DNA hybridization (dDDH) value (55.5 %) with the type strain of V. infantium . The two strains reported in this study were distinguished from the previously reported species from the genus Veillonella based on catalase production, partial dnaK, rpoB and gltA sequences, average ANI and dDDH values. Based on these observations, the two strains represent a novel species, for which the name Veillonella nakazawae sp. nov. is proposed. The type strain is T1-7T (JCM 33966T=CCUG 74597T).

scholarly journals Does concomitant bacteraemia hide the fungi in blood cultures? An in vitro study

2020 ◽  
Vol 69 (7) ◽  
pp. 944-948
Author(s):  
Yasemin Oz ◽  
Sukran Onder ◽  
Ekin Alpaslan ◽  
Gul Durmaz
Keyword(s):  
Blood Culture ◽  
Bloodstream Infection ◽  
Microscopic Examination ◽  
Type Species ◽  
Blood Cultures ◽  
Specific Patient ◽  
Content Type ◽  
Link Type ◽  
Direct Microscopic Examination ◽  
Positive Direct

Introduction. Polymicrobial infections including yeasts and bacteria are not rare and patients with polymicrobial bloodstream infection have higher early and overall case fatality rates. The diagnosis of invasive fungal and bacterial infections is mainly based on blood culture. Aim. The aim was to reveal the effect of concomitant bacteraemia on the detection of fungi from blood cultures in the presence of polymicrobial bloodstream infections involving Candida and non-Candida fungi and to show the superiority of blood culture bottles including selective fungal media in such situations. Methodology. Twenty-four polymicrobial bloodstream infection models – involving one fungus and one bacterium – were constituted by using clinical blood culture isolates ( Escherichia coli , Staphylococcus aureus , Pseudomonas aeruginosa , Candida albicans, Candida glabrata, Fusarium solani and Trichosporon asahii). The Plus Aerobic/F (PAF) and Mycosis IC/F (MICF) culture bottles were used with the BACTEC 9240 device. After a bottle signalled positive, direct microscopic examination and subcultures on agar plates were performed. Results. All of fungi that were inoculated alone and in combination were detected by both direct microscopic examination and subcultures on agar plates from MICF bottles, whereas direct microscopic examination only revealed the bacterial agents from PAF bottles including combinations. Furthermore, fungal growth was hidden by bacterial growth on blood agar subcultures from PAF bottles including combinations of F. solani, C. glabrata or T. asahii with bacteria. Conclusion. Blood culture bottles including selective fungal media that can allow selective growth of fungi and earlier detection of some species should be preferred in addition to non-selective blood culture bottles, especially in specific patient populations. Further, the use of selective agar plates such as inhibitory mould agar may contribute to the solution of this problem in clinical laboratories.

scholarly journals Co-infection in critically ill patients with COVID-19: an observational cohort study from England

2021 ◽  
Vol 70 (4) ◽  
Author(s):  
Vadsala Baskaran ◽  
Hannah Lawrence ◽  
Louise E. Lansbury ◽  
Karmel Webb ◽  
Shahideh Safavi ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Cohort Study ◽  
Streptococcus Pneumoniae ◽  
Critically Ill ◽  
Type Species ◽  
Severe Illness ◽  
Gram Negative ◽  
Content Type ◽  
Link Type ◽  
Icu Stay

Introduction. During previous viral pandemics, reported co-infection rates and implicated pathogens have varied. In the 1918 influenza pandemic, a large proportion of severe illness and death was complicated by bacterial co-infection, predominantly Streptococcus pneumoniae and Staphylococcus aureus . Gap statement. A better understanding of the incidence of co-infection in patients with COVID-19 infection and the pathogens involved is necessary for effective antimicrobial stewardship. Aim. To describe the incidence and nature of co-infection in critically ill adults with COVID-19 infection in England. Methodology. A retrospective cohort study of adults with COVID-19 admitted to seven intensive care units (ICUs) in England up to 18 May 2020, was performed. Patients with completed ICU stays were included. The proportion and type of organisms were determined at <48 and >48 h following hospital admission, corresponding to community and hospital-acquired co-infections. Results. Of 254 patients studied (median age 59 years (IQR 49–69); 64.6 % male), 139 clinically significant organisms were identified from 83 (32.7 %) patients. Bacterial co-infections/ co-colonisation were identified within 48 h of admission in 14 (5.5 %) patients; the commonest pathogens were Staphylococcus aureus (four patients) and Streptococcus pneumoniae (two patients). The proportion of pathogens detected increased with duration of ICU stay, consisting largely of Gram-negative bacteria, particularly Klebsiella pneumoniae and Escherichia coli . The co-infection/ co-colonisation rate >48 h after admission was 27/1000 person-days (95 % CI 21.3–34.1). Patients with co-infections/ co-colonisation were more likely to die in ICU (crude OR 1.78,95 % CI 1.03–3.08, P=0.04) compared to those without co-infections/ co-colonisation. Conclusion. We found limited evidence for community-acquired bacterial co-infection in hospitalised adults with COVID-19, but a high rate of Gram-negative infection acquired during ICU stay.

Evaluation of the rapid ResaPolymyxin Acinetobacter/Pseudomonas NP test for rapid colistin resistance detection in lactose non-fermenting Gram-negative bacteria

2021 ◽  
Vol 70 (6) ◽  
Author(s):  
Hyunsul Jung ◽  
Johann D. D. Pitout ◽  
Barend C. Mitton ◽  
Kathy-Anne Strydom ◽  
Chanel Kingsburgh ◽  
...  
Keyword(s):  
Type Species ◽  
Susceptibility Testing ◽  
Multidrug Resistant ◽  
Gram Negative Bacteria ◽  
Major Error ◽  
Colistin Resistance ◽  
Gram Negative ◽  
Content Type ◽  
Link Type ◽  
Extensively Drug Resistant

Introduction. Colistin is one of the last-resort antibiotics for treating multidrug-resistant (MDR) or extensively drug-resistant (XDR) lactose non-fermenting Gram-negative bacteria such as Pseudomonas aeruginosa and Acinetobacter baumannii . Gap Statement. As the rate of colistin resistance is steadily rising, there is a need for rapid and accurate antimicrobial susceptibility testing methods for colistin. The Rapid ResaPolymyxin Acinetobacter / Pseudomonas NP test has recently been developed for rapid detection of colistin resistance in P. aeruginosa and A. baumannii . Aim. The present study aimed to evaluate the performance of the Rapid ResaPolymyxin Acinetobacter / Pseudomonas NP test in comparison with the reference broth microdilution (BMD) method. Methodology. The Rapid ResaPolymyxin Acinetobacter / Pseudomonas NP test was performed using a total of 135 P . aeruginosa (17 colistin-resistant and 118 colistin-susceptible) and 66 A. baumannii isolates (32 colistin-resistant and 34 colistin-susceptible), in comparison with the reference BMD method. Results. The categorical agreement of the Rapid ResaPolymyxin Acinetobacter / Pseudomonas NP test with the reference BMD method was 97.5 % with a major error rate of 0 % (0/152) and a very major error (VME) rate of 10.2 %. The VME rate was higher (23.5 %) when calculated separately for P. aeruginosa isolates. The overall sensitivity and specificity were 89.8 and 100 %, respectively. Conclusion. The Rapid ResaPolymyxin Acinetobacter / Pseudomonas NP test performed better for A. baumannii than for P. aeruginosa .

scholarly journals Salipiger nanhaiensis sp. nov., a bacterium isolated from deep sea water

2015 ◽  
Vol 65 (Pt_4) ◽  
pp. 1122-1126 ◽  
Author(s):  
Xiaofeng Dai ◽  
Xiaochong Shi ◽  
Xin Gao ◽  
Jing Liang ◽  
Xiao-Hua Zhang
Keyword(s):  
Phylogenetic Analysis ◽  
Type Species ◽  
Sea Water ◽  
Sequence Similarity ◽  
Rrna Gene ◽  
Respiratory Quinone ◽  
Content Type ◽  
Link Type ◽  
Major Respiratory Quinone ◽  
Positive Results

A Gram-stain-negative, facultatively anaerobic, chemoheterotrophic, moderately halophilic, exopolysaccharide (EPS)-producing, cream, non-motile and rod-shaped bacterium, designated strain ZH114T, was isolated from deep water of the South China Sea, and was subjected to a polyphasic taxonomic study. Phylogenetic analysis, based on 16S rRNA gene sequences, indicated that this strain belongs to the genus Salipiger with the highest sequence similarity to Salipiger mucescens LMG 22090T (96.83 %), followed by Pseudodonghicola xiamenensis LMG 24574T (96.12 %). Growth occurred at 4–37 °C (optimum 32 °C), pH 6.0–10.0 (optimum pH 9.0–10.0) and in the presence of 0–19 % NaCl (w/v) (optimum 6 %, w/v). It did not produce poly-β-hydroxyalkanoate granules or bacteriochlorophyll a. Acid was produced from glycerol, erythrose, ribose, d-xylose, galactose, glucose, fructose, mannitol, cellobiose, maltose, lactose, melibiose, turanose, d-lyxose, d-tagatose, d-fucose, d-arabitol and l-arabitol after inoculating for 24 h and weakly positive results were also detected after 48 h in API 50CH strips with d-arabinose, l-arabinose, l-xylose, adonitol, mannose, aesculin, salicin, sucrose, mycose and l-fucose. The predominant fatty acids were C18 : 1ω7c and/or C18 : 1ω6c, C16 : 0, C18 : 0 and 11-methyl C18 : 1ω7c. The major polar lipids of ZH114T were phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine and two unidentified lipids. The major respiratory quinone was ubiquinone Q-10. The genomic DNA G+C content of strain ZH114T was 63.8 mol%. Based on this phenotypic, chemotaxonomic and phylogenetic analysis, strain ZH114T should be classified as a representative of a novel species of the genus Salipiger , for which the name Salipiger nanhaiensis sp. nov. is proposed. The type strain is ZH114T ( = JCM 19383T = KCTC 32468T).

scholarly journals Predatory bacteria as living antibiotics – where are we now?

Microbiology ◽  
2021 ◽  
Vol 167 (1) ◽  
Author(s):  
Robert J. Atterbury ◽  
Jess Tyson
Keyword(s):  
Antimicrobial Resistance ◽  
Global Health ◽  
Type Species ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Content Type ◽  
Biologically Relevant ◽  
Link Type ◽  
Predatory Bacteria

Antimicrobial resistance (AMR) is a global health and economic crisis. With too few antibiotics in development to meet current and anticipated needs, there is a critical need for new therapies to treat Gram-negative infections. One potential approach is the use of living predatory bacteria, such as Bdellovibrio bacteriovorus (small Gram-negative bacteria that naturally invade and kill Gram-negative pathogens of humans, animals and plants). Moving toward the use of Bdellovibrio as a ‘living antibiotic’ demands the investigation and characterization of these bacterial predators in biologically relevant systems. We review the fundamental science supporting the feasibility of predatory bacteria as alternatives to antibiotics.

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