scholarly journals Intracellular Accumulation of Linezolid and Florfenicol in OptrA-Producing Enterococcus faecalis and Staphylococcus aureus

Molecules ◽  
2018 ◽  
Vol 23 (12) ◽  
pp. 3195 ◽  
Author(s):  
Yingyu Wang ◽  
Xiaowei Li ◽  
Yang Wang ◽  
Stefan Schwarz ◽  
Jianzhong Shen ◽  
...  

The optrA gene, which confers transferable resistance to oxazolidinones and phenicols, is defined as an ATP-binding cassette (ABC) transporter but lacks transmembrane domains. The resistance mechanism of optrA and whether it involves antibiotic efflux or ribosomal protection remain unclear. In this study, we determined the MIC values of all bacterial strains by broth microdilution, and used ultra-high performance liquid chromatography-tandem quadrupole mass spectrometry to quantitatively determine the intracellular concentrations of linezolid and florfenicol in Enterococcus faecalis and Staphylococcus aureus. Linezolid and florfenicol both accumulated in susceptible strains and optrA-carrying strains of E. faecalis and S. aureus. No significant differences were observed in the patterns of drug accumulation among E. faecalis JH2-2, E. faecalis JH2-2/pAM401, and E. faecalis JH2-2/pAM401+optrA, but also among S. aureus RN4220, S. aureus RN4220/pAM401, and S. aureus RN4220/pAM401+optrA. ANOVA scores also suggested similar accumulation conditions of the two target compounds in susceptible strains and optrA-carrying strains. Based on our findings, the mechanism of optrA-mediated resistance to oxazolidinones and phenicols obviously does not involve active efflux and the OptrA protein does not confer resistance via efflux like other ABC transporters.

2021 ◽  
Vol 5 (1) ◽  
pp. 1-9
Author(s):  
Antonio Carlos Pereira de Menezes Filho ◽  
Matheus Vinícius Abadia Ventura ◽  
Carlos Frederico de Souza Castro

Tibouchina granulosa is a species that blooms annually in several regions of Brazil. This species is still little explored in terms of phytocompounds in all organs of this plant, especially the floral organ. Flowers of T. granulosa were collected in the municipality of Rio Verde, Goiás, Brazil, in 2021. The hydroethanolic floral extract was prepared by maceration and qualitative phytochemical (colorimetric reactions and salt formation) and antibacterial analyzes performed and the results expressed in millimeters of inhibition at different concentrations in mg mL-1. Several phytochemical classes were observed with positive results, especially for alkaloids, phenolics, oxylates, saponins, carbohydrates and tannins. As for the bacterial assay, potential antibacterial activity was observed for all bacterial strains tested, except for Salmonella serovar Thyphymurium and serovar Enteritidis. Expressive inhibitions were observed for Enterococcus faecalis > Pseudomonas aeruginosa > Staphylococcus aureus and Escherichia coli at the highest concentrations between 100-50 mg mL-1. The floral extract of Tibouchina granulosa showed phytotherapeutic potential with the presence of several phytochemical groups and expressive antibacterial activity.


Author(s):  
A. A. Katun ◽  
A. R. Abdulmumin ◽  
M. U. Yahaya ◽  
N. K. Habeeb ◽  
A. Bala

The investigation into soil bacteria has been widely studied and becoming increasingly appreciated as an exceptional reservoir of unique naturally occurring biologically active metabolites with pharmaceutical applications. This article aimed to isolate, identify and biochemically characterize antibiotic-producing bacteria from anthill soils in the permanent site of Ibrahim Badamasi Babangida University, Lapai (IBBUL), Niger State, Nigeria. The sum of ten samples were collected from five sampling sites, the sampling was done in threefold (morning, noon and evening) and analyzed adopting standard microbiological protocols. The obtained result revealed that the total bacteria count in the morning ranges from 2.1×107 cfu/mL to 1.4×106 cfu/mL, noon count ranges from 3.1×107 to 2.6×106 cfu/mL while evening count was in the range of 2.1×107 cfu/mL to 1.7×106 cfu/mL. A total number of five (5) bacteria were isolated as Staphylococcus aureus, Staphylococcus epidermidis, Bacillus subtilis, Bacillus lentus and Micrococcus reseus. The total prevalence of the bacterial isolates in the morning, noon and evening were calculated as B. subtilis (109.08%), S. epidermidis (36.36%), M. reseus (36.36%), B. lentus (63.63%), and S. aureus (54.54%) respectively. These isolates were further assayed against Escherichia coli, Salmonella typhi, Klebsiella sp. and Staphylococcus aureus. The antibacterial outcome showed that two (2) (40%) anthill isolates exhibited antibacterial activity against three (3) tested bacteria (Escherichia coli, Salmonella typhi and Staphylococcus aureus). This research study has showcased that the production of inhibitory substances are common among some of the bacterial strains isolated from anthills.


2018 ◽  
Vol 12 (2) ◽  
pp. 1-14
Author(s):  
Fabrice Ezo’o Mengo ◽  
Stéphanie Claire Tchonang ◽  
Hermann Ludovic Kemaleu ◽  
Sylvain Leroy Sado Kamdem ◽  
Jean Justin Essia Ngang

2017 ◽  
Vol 24 (1) ◽  
pp. 23-31 ◽  
Author(s):  
Fatimah A. Nashawi ◽  
Hani Y. Abdullah ◽  
Nahlaa A. Khalifa ◽  
Ibrahim A. Alzahrani ◽  
Ahmed A. Al-Ghamdi

To evaluate the antibacterial eff ects of three types of Saudi honey (Feghra, Sider and Natural honey) alone and mixed with ginger or lemon in comparison to Manuka honey as a potential natural antibacterial agent. Saudi honeys were evaluated against five types of bacterial strains; Klebsiella pneumoniae, Staphylococcus aureus, Pseudomonas aeruginosa, Haemophilus influenzae and Streptococcus pneumoniae. Chocolate agars were prepared first with different concentrations of each type of honey, and then with specific concentrations either of ginger or lemon added to honey. Bacterial species were inoculated on each agar and incubated at 37oC in a CO2 incubator overnight. Significant differences were found between diff erent types of honey and different concentrations of the same honey on bacterial growth. There are no significant differences and synergistic effects when adding ginger to diff erent honey types. Addition of lemon show significant differences and good synergistic effects against all tested bacterial species except Klebsiella pneumoniae and Staphylococcus aureus at 15 and 20% honey concentration. In conclusion, antibacterial effects of different types of honey are type and concentration dependent. Adding lemon to the different types of honey changes the pH and acidity and increases the honey’s antibacterial effect.


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