scholarly journals Strain typing and characterization of virulence genes in clinicalStaphylococcus aureusisolates from Kenya

2018 ◽  
Author(s):  
Cecilia Kyany’a ◽  
Justin Nyasinga ◽  
Daniel Matano ◽  
Valerie Oundo ◽  
Simon Wacira ◽  
...  
Keyword(s):  
Virulence Genes ◽  
Illumina Miseq ◽  
Strain Typing ◽  
Toxin Genes ◽  
Severe Infections ◽  
Potential Risks ◽  
Hospital Acquired ◽  
Spa Types ◽  
Highly Virulent

AbstractStaphylococcusaureusstrain typing is an important surveillance tool as particular strains have been associated with virulence and community and hospital acquired MRSA outbreaks globally. This study sought to determine the circulating strain types ofS.aureusin Kenya and establish the virulence genes among the strains. ClinicalS.aureusisolates from 3 hospitals in Kenya were sequenced on the Illumina Miseq and genomes assembled and annotated on PATRIC. Results demonstrated great diversity among the isolates with identification of 6 distinct CC (8,22,15,80,121,152), 8 ST types (8, 15, 22,80,121,152,241, 1633) and 8 spa types (t005, t037, t064, t084, t233, t2029, t272,t355). Novel STs (4705, 4707) and a novel spa type (t17826) were identified. The most prominent clonal complex was CC 152 comprised of only MSSA. A majority of MRSA isolates (3/4) typed to ST 241, CC8. One MRSA isolate typed to a novel ST 4705. All isolates were screened for a panel of 56 known virulence genes (19 adhesins, 9 hemolysins, 5 immune evasion proteins, 6 exo-enzymes and 19 toxins). 9 toxin genes were detected among the isolates with CC8 isolates having the highest numbers of toxin genes. An MSSA isolate (CC8) from a severe burn infection had the highest number of toxin genes (5). All MRSA isolates (CC8) had only 2 toxins, SEK and SEQ, whereas a majority of the MSSA isolates either had 0 or ≥2 toxins. SEK+SEQ and TSST-1+SEB+SEL toxin combinations were observed among patients whose disease resulted in hospitalization, an indicator of severe infections. This study confirms the highly heterogeneousS.aureuspopulation in Kenya. MSSA appear to have the potential of accumulating more toxin genes than MRSA. This co-occurrence of major toxin genes, some associated with MRSA, highlights the potential risks of outbreaks of highly virulent MRSA infections which would pose treatment challenges.

scholarly journals Phenotypic and genotypic characterization of clinical Staphylococcus aureus isolates from Kenya

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Cecilia Kyany’a ◽  
Justin Nyasinga ◽  
Daniel Matano ◽  
Valerie Oundo ◽  
Simon Wacira ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Virulence Genes ◽  
Genetic Relationships ◽  
Illumina Miseq ◽  
The Novel ◽  
Severe Infections ◽  
Resistant Strains ◽  
Susceptibility Profiles ◽  
Genotype Concordance

Abstract Background The increase and spread of virulent-outbreak associated, methicillin and vancomycin resistant (MRSA/VRSA) Staphylococcus aureus require a better understanding of the resistance and virulence patterns of circulating and emerging strains globally. This study sought to establish the resistance phenotype, and strains of 32 non-duplicate clinical MRSA and MSSA S. aureus isolates from four Kenyan hospitals, identify their resistance and virulence genes and determine the genetic relationships of MRSA with global strains. Methods Antimicrobial susceptibility profiles were determined on a Vitek 2, genomic DNA sequenced on an Illumina Miseq and isolates typed in-silico. Resistance and virulence genes were identified using ARIBA and phylogenies generated using RAxML. Results The MRSA isolates were 100% susceptible to vancomycin, teicoplanin, linezolid, and tigecycline. Nine distinct CC, 12 ST and 15 spa types including the novel t17826 and STs (4705, 4707) were identified with CC8 and CC152 predominating. MRSA isolates distributed across 3 CCs; CC5-ST39 (1), CC8 – ST241 (4), a novel CC8-ST4705 (1), ST8 (1) and CC152 (1). There was > 90% phenotype-genotype concordance with key resistance genes identified only among MRSA isolates: gyrA, rpoB, and parC mutations, mecA, ant (4′)-lb, aph (3′)-IIIa, ermA, sat-4, fusA, mphC and msrA. Kenyan MRSA isolates were genetically diverse and most closely related to Tanzanian and UK isolates. There was a significant correlation between map, hlgA, selk, selq and cap8d virulence genes and severe infections. Conclusion The findings showed a heterogeneous S. aureus population with novel strain types. Though limited by the low number of isolates, this study begins to fill gaps and expand our knowledge of S. aureus epidemiology while uncovering interesting patterns of distribution of strain types which should be further explored. Although last-line treatments are still effective, the potential for outbreaks of both virulent and resistant strains remain, requiring sustained surveillance of S. aureus populations.

scholarly journals Multidrug-Resistant Klebsiella pneumoniae Causing Severe Infections in the Neuro-ICU

Antibiotics ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 979
Author(s):  
Nadezhda K. Fursova ◽  
Evgenii I. Astashkin ◽  
Olga N. Ershova ◽  
Irina A. Aleksandrova ◽  
Ivan A. Savin ◽  
...  
Keyword(s):  
Klebsiella Pneumoniae ◽  
Virulence Genes ◽  
Illumina Miseq ◽  
Multidrug Resistant ◽  
Genetic Lineages ◽  
Severe Infections ◽  
Miseq Platform ◽  
Vitek 2 ◽  
Systemic Infections ◽  
Sequence Types

The purpose of this study was the identification of genetic lineages and antimicrobial resistance (AMR) and virulence genes in Klebsiella pneumoniae isolates associated with severe infections in the neuro-ICU. Susceptibility to antimicrobials was determined using the Vitek-2 instrument. AMR and virulence genes, sequence types (STs), and capsular types were identified by PCR. Whole-genome sequencing was conducted on the Illumina MiSeq platform. It was shown that K. pneumoniae isolates of ST14K2, ST23K57, ST39K23, ST76K23, ST86K2, ST218K57, ST219KL125/114, ST268K20, and ST2674K47 caused severe systemic infections, including ST14K2, ST39K23, and ST268K20 that were associated with fatal incomes. Moreover, eight isolates of ST395K2 and ST307KL102/149/155 were associated with manifestations of vasculitis and microcirculation disorders. Another 12 K. pneumoniae isolates of ST395K2,KL39, ST307KL102/149/155, and ST147K14/64 were collected from patients without severe systemic infections. Major isolates (n = 38) were XDR and MDR. Beta-lactamase genes were identified: blaSHV (n = 41), blaCTX-M (n = 28), blaTEM (n = 21), blaOXA-48 (n = 21), blaNDM (n = 1), and blaKPC (n = 1). The prevalent virulence genes were wabG (n = 41), fimH (n = 41), allS (n = 41), and uge (n = 34), and rarer, detected only in the genomes of the isolates causing severe systemic infections—rmpA (n = 8), kfu (n = 6), iroN (n = 5), and iroD (n = 5) indicating high potential of the isolates for hypervirulence.

scholarly journals Synthesis, Characterization and Bactericidal Activity of a 4-Ammoniumbuthylstyrene-Based Random Copolymer

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1140
Author(s):  
Silvana Alfei ◽  
Gabriella Piatti ◽  
Debora Caviglia ◽  
Anna Maria Schito
Keyword(s):  
Antibacterial Activity ◽  
Bactericidal Activity ◽  
Antimicrobial Agents ◽  
Water Solubility ◽  
Physicochemical Characterization ◽  
Random Copolymer ◽  
Water Soluble ◽  
Cationic Polymers ◽  
Severe Infections

The growing resistance of bacteria to current chemotherapy is a global concern that urgently requires new and effective antimicrobial agents, aimed at curing untreatable infection, reducing unacceptable healthcare costs and human mortality. Cationic polymers, that mimic antimicrobial cationic peptides, represent promising broad-spectrum agents, being less susceptible to develop resistance than low molecular weight antibiotics. We, thus, designed, and herein report, the synthesis and physicochemical characterization of a water-soluble cationic copolymer (P5), obtained by copolymerizing the laboratory-made monomer 4-ammoniumbuthylstyrene hydrochloride with di-methyl-acrylamide as uncharged diluent. The antibacterial activity of P5 was assessed against several multi-drug-resistant clinical isolates of both Gram-positive and Gram-negative species. Except for strains characterized by modifications of the membrane charge, most of the tested isolates were sensible to the new molecule. P5 showed remarkable antibacterial activity against several isolates of genera Enterococcus, Staphylococcus, Pseudomonas, Klebsiella, and against Escherichia coli, Acinetobacter baumannii and Stenotrophomonas maltophilia, displaying a minimum MIC value of 3.15 µM. In time-killing and turbidimetric studies, P5 displayed a rapid non-lytic bactericidal activity. Due to its water-solubility and wide bactericidal spectrum, P5 could represent a promising novel agent capable of overcoming severe infections sustained by bacteria resistant the presently available antibiotics.

scholarly journals Updated Characterization of Races of Plasmopara halstedii and Entomopathogenic Fungi as Endophytes of Sunflower Plants in Axenic Culture

Agronomy ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 268
Author(s):  
Pedro Miranda-Fuentes ◽  
Ana B. García-Carneros ◽  
Leire Molinero-Ruiz
Keyword(s):  
Plant Growth ◽  
Downy Mildew ◽  
Entomopathogenic Fungi ◽  
Genetic Resistance ◽  
Axenic Culture ◽  
Plasmopara Halstedii ◽  
Successful Establishment ◽  
Axenic Conditions ◽  
Highly Virulent

The management of downy mildew (Plasmopara halstedii) in sunflower, is heavily dependent on genetic resistance, whilst entomopathogenic fungi (EF) can reduce other sunflower diseases. In this work, we characterized P. halstedii from Spain and other countries collected in the past few years. Twenty-three races were identified (the most frequent in Spain being 310, 304, 705 and 715), with an increasing proportion of highly virulent races. Five isolates from countries other than Spain overcame the resistance in RHA-340. In addition, we assessed the efficacy of five EF against downy mildew and their effects on sunflower growth in axenic conditions. None of the entomopathogens reduced disease severity, nor did they have any effect on plant growth when applied together with P. halstedii. In contrast, three EF reduced some of the plant growth variables in the absence of the pathogen. Microbiological and molecular diagnostics suggest that the axenic system and the short experimental time used in this study did not favor the successful establishment of EF in the plants or their potential biocontrol effect. Our results show a shift in P. halstedii racial patterns and suggest that soil as a growth substrate and long infection times are needed for EF effectiveness against downy mildew.

scholarly journals Arbuscular Mycorrhizal Fungal Communities in the Soils of Desert Habitats

2021 ◽  
Vol 9 (2) ◽  
pp. 229
Author(s):  
Martti Vasar ◽  
John Davison ◽  
Siim-Kaarel Sepp ◽  
Maarja Öpik ◽  
Mari Moora ◽  
...  
Keyword(s):  
Plant Root ◽  
Significant Proportion ◽  
Arbuscular Mycorrhizal ◽  
Am Fungi ◽  
Illumina Miseq ◽  
Desert Ecosystems ◽  
Fungal Dna ◽  
Root Symbionts ◽  
Arbuscular Mycorrhizal Fungal

Deserts cover a significant proportion of the Earth’s surface and continue to expand as a consequence of climate change. Mutualistic arbuscular mycorrhizal (AM) fungi are functionally important plant root symbionts, and may be particularly important in drought stressed systems such as deserts. Here we provide a first molecular characterization of the AM fungi occurring in several desert ecosystems worldwide. We sequenced AM fungal DNA from soil samples collected from deserts in six different regions of the globe using the primer pair WANDA-AML2 with Illumina MiSeq. We recorded altogether 50 AM fungal phylotypes. Glomeraceae was the most common family, while Claroideoglomeraceae, Diversisporaceae and Acaulosporaceae were represented with lower frequency and abundance. The most diverse site, with 35 virtual taxa (VT), was in the Israeli Negev desert. Sites representing harsh conditions yielded relatively few reads and low richness estimates, for example, a Saudi Arabian desert site where only three Diversispora VT were recorded. The AM fungal taxa recorded in the desert soils are mostly geographically and ecologically widespread. However, in four sites out of six, communities comprised more desert-affiliated taxa (according to the MaarjAM database) than expected at random. AM fungal VT present in samples were phylogenetically clustered compared with the global taxon pool, suggesting that nonrandom assembly processes, notably habitat filtering, may have shaped desert fungal assemblages.

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