BSAC standardized disc susceptibility testing method

Andrews, J. M.

doi:10.1093/jac/48.suppl_1.43

Cited by 265 publications

(100 citation statements)

References 4 publications

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“…Antibiotic susceptibilities were determined for ciprofloxacin (1 g), cephalothin (30 g), ampicillin (10 g), kanamycin (10 g), tetracycline (10 g), gentamicin (10 g), and trimethoprimsulfamethoxazole (25 g). Disc diffusion assays were performed according to the standardized British Society for Antimicrobial Chemotherapy (BSAC) disc diffusion method for antimicrobial susceptibility testing (38). Plates were incubated for 48 h at 37°C.…”

Section: Chemicalmentioning

confidence: 99%

Altered Competitive Fitness, Antimicrobial Susceptibility, and Cellular Morphology in a Triclosan-Induced Small-Colony Variant of Staphylococcus aureus

Forbes

Latimer

Bazaid

et al. 2015

Antimicrob Agents Chemother

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Staphylococcus aureus can produce small-colony variants (SCVs) that express various phenotypes. While their significance is unclear, SCV propagation may be influenced by relative fitness, antimicrobial susceptibility, and the underlying mechanism. We have investigated triclosan-induced generation of SCVs in six S. aureus strains, including methicillin-resistant S. aureus (MRSA). Parent strains (P0) were repeatedly passaged on concentration gradients of triclosan using a solid-state exposure system to generate P10. P10 was subsequently passaged without triclosan to generate X10. Susceptibility to triclosan and 7 antibiotics was assessed at all stages. For S. aureus ATCC 6538, SCVs were further characterized by determining microbicide susceptibility and competitive fitness. Cellular morphology was examined using electron microscopy, and protein expression was evaluated through proteomics. Triclosan susceptibility in all SCVs (which could be generated from 4/6 strains) was markedly decreased, while antibiotic susceptibility was significantly increased in the majority of cases. An SCV of S. aureus ATCC 6538 exhibited significantly increased susceptibility to all tested microbicides. Cross-wall formation was impaired in this bacterium, while expression of FabI, a target of triclosan, and IsaA, a lytic transglycosylase involved in cell division, was increased. The P10 SCV was 49% less fit than P0. In summary, triclosan exposure of S. aureus produced SCVs in 4/6 test bacteria, with decreased triclosan susceptibility but with generally increased antibiotic susceptibility. An SCV derived from S. aureus ATCC 6538 showed reduced competitive fitness, potentially due to impaired cell division. In this SCV, increased FabI expression could account for reduced triclosan susceptibility, while IsaA may be upregulated in response to cell division defects. Staphylococcus aureus small-colony variants (SCVs) are characterized by low growth rate and the formation of small nonpigmented colonies (1, 2). They are commonly, but not exclusively, related to antibiotic exposure (3) and have been shown to display diverse phenotypic characteristics, including reduced beta-hemolysis, coagulase, and DNase activities (4), enhanced intracellular survival (5), impaired biofilm formation (6), reduced virulence (6), and low intrinsic susceptibility to certain antibiotics, cationic microbicides, and antimicrobial peptides (7,8). While all SCVs are not physiologically the same, certain SCVs have been reported to cause persistent skin, bone, and device-associated infections, and they have been isolated from patients undergoing prolonged antibiotic therapy (2, 9, 10). Due to their uncommon morphological features and pinpoint colony size, SCVs may be overlooked or misidentified in clinical microbiology laboratories, potentially confounding their identification.The phenotypic variation observed in S. aureus SCVs is often attributed to auxotrophy for menadione, hemin, or thiamine due to mutations in their respective genes. This results in impaired synthesis...

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Section: Chemicalmentioning

confidence: 99%

Altered Competitive Fitness, Antimicrobial Susceptibility, and Cellular Morphology in a Triclosan-Induced Small-Colony Variant of Staphylococcus aureus

Forbes

Latimer

Bazaid

et al. 2015

Antimicrob Agents Chemother

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“…The antimicrobial activity was tested by the disc diffusion technique [17]. Different concentrations of the extract were prepared by reconstituting the stock with distilled water.…”

Section: Antimicrobial Activity Test and Determination Of Minimum Inhmentioning

confidence: 99%

Physicochemical Properties and Antimicrobial Activity of Evaporated Extract of Cow Dung Against Some Pathogens

Waziri

Suleiman

2012

J. Sci. Res.

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The evaporated extract of cow dung is traditionally used in Northern Nigeria and Cameroun as food additive and in treatment of infectious diseases. In this study, the cow dung ash extract was prepared and tested for some elemental contents as well as the antimicrobial activity against Cyanobacteria (C.bacteria), Staphylococcus aureus (S.aureus), Bacillus subtilis (B.subtilis) and Escherichia coli (E.coli) using different analytical techniques. The extract was highly basic with pH of 11.7 and the elements vary in the following decreasing order of concentration; K>Na>Mg>Ca>Fe>Al>Zn. S. aureus was the most sensitive bacteria with minimum inhibitory concentration (MIC) value of 0.082 mg/mL while B.subtilis was the least sensitive with MIC value of 4.3 mg/mL. The result of this study indicate that the extract can supplement the dietary Na and K requirements for the users and supports the folkloric use of the extract in treatment of infections.

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“…Before the test, cell suspensions were carefully washed three times with 0.86 % sterile saline solution. Bacterial resistance was assessed by the disc diffusion (Kirby-Bauer) method (Andrews, 2008) and the Biolog GEN III MicroPlate (the chemicals and their concentrations are listed in Table S3). The major respiratory quinones were extracted and analysed by HPLC fitted with a reversed-phase column as described by Komagata & Suzuki (1987).…”

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confidence: 99%

Glycocaulis albus sp. nov., a moderately halophilic dimorphic prosthecate bacterium isolated from petroleum-contaminated saline soil

Xie

Cai

et al. 2014

International Journal of Systematic and Evolutionary Microbiology

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Two novel bacterial strains, SLG210-30A1 T and SLG210-19A2, which shared 99.9 % 16S rRNA gene sequence similarity with each other, were isolated from petroleum-contaminated saline soil in Shengli Oilfield, eastern China. Cells were Gram-stain-negative, motile, aerobic, mesophilic and moderately halophilic. They could grow chemoheterotrophically with oxygen as an electron acceptor. Morphologically, cells were typical Caulobacteria-type dimorphic prosthecate bacteria. The genomic DNA G+C contents of strains SLG210-30A1 T and SLG210-19A2 were 61.8 mol% and 61.6 mol% respectively. Strain SLG210-30A1 T had Q10 as the predominant respiratory ubiquinone, and C 16 : 0 (28.4 %), C 17 : 0 (11.6 %), C 18 : 0 (22.1 %) and C 18 : 1 v7c (14.0 %) as the major cellular fatty acids. The polar lipids of the two isolates were some glycolipids, a lipid, a phospholipid, an aminoglycolipid and an aminophospholipid (all unidentified). The 16S rRNA gene sequences of strains SLG210-30A1 T and SLG210-19A2 showed the highest similarities with Glycocaulis abyssi MCS 33 T (99.8-99.9 %), but low sequence similarities (,94.7 %) with type strains of other members of the family Hyphomonadaceae. However, the DNA-DNA relatedness of G. abyssi MCS 33 T to strains SLG210-30A1 T and SLG210-19A2 was 37.4±4.4 % and 36.1±1.1 %, respectively. Based on different physiological, biochemical, and phylogenetic characteristics, strains SLG210-30A1 T and SLG210-19A2 represent a novel species of the genus Glycocaulis. The name Glycocaulis albus is therefore proposed with strain SLG210-30A1 T (5LMG 27741 T 5CGMCC 1.12766 T ) as the type strain. An emended description of the genus Glycocaulis is also provided.In 2005, Lee et al. divided the order Caulobacterales proposed by Henrici & Johnson (1935) into three families: Caulobacteraceae, Hyphomonadaceae and 'Rhodobacteriaceae' (Lee et al., 2005). The family Hyphomonadaceae contained 14 genera and 31 species at the time of writing, with members isolated mainly from marine environments, and sharing similar morphological, physiological and biochemical features (Weiner et al., 2000;Wu et al., 2009 After grown in LB medium at 37 u C for 1 day when cell growth reached exponential phase, the cell morphology of strain SLG210-30A1 T was observed by transmission electron microscopy (JEM-1230; JEOL) and Gram-staining was examined with light microscopy (Tindall et al., 2010). The temperature range for cell growth was tested in liquid LB medium at 4, 15, 20, 25, 30, 37, 40, 45, 50 and 55 u C while NaCl and pH were kept at 1 % and pH 8.0, respectively. The salt requirement for growth was tested with NaCl concentrations ranging from 0-10 % (w/v) at 1 % intervals (Imhoff & Caumette, 2004), while temperature and pH were kept at 37 u C and pH 8.0, respectively. The pH range for growth was tested at pH 4, 5, 6, 7, 7.6, 8, 8.6, 9 and 10 (Takai et al., 2002), while temperature and NaCl were kept at 37 u C and 1 %, respectively. These tests were performed in triplicate with strains SLG210-30A1 T , SLG210-19A2 and G. abyssi MCS 33 T . ...

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BSAC standardized disc susceptibility testing method

Cited by 265 publications

References 4 publications

Altered Competitive Fitness, Antimicrobial Susceptibility, and Cellular Morphology in a Triclosan-Induced Small-Colony Variant of Staphylococcus aureus

Altered Competitive Fitness, Antimicrobial Susceptibility, and Cellular Morphology in a Triclosan-Induced Small-Colony Variant of Staphylococcus aureus

Physicochemical Properties and Antimicrobial Activity of Evaporated Extract of Cow Dung Against Some Pathogens

Glycocaulis albus sp. nov., a moderately halophilic dimorphic prosthecate bacterium isolated from petroleum-contaminated saline soil

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