Microbiology
Karl H. Pang, Nadir I. Osman, James W.F. Catto, Christopher R. Chapple in Basic Urological Sciences, 2021
A standard sample of urine is inoculated onto blood agar.Cysteine-lactose -electrolyte-deficient (CLED) or chromogenic agar and incubated overnight at 37°C.Cultures on chromogenic agar help identity bacteria and further tests might then be needed.Additional agar plates can be added based on microscopy or clinical details.Example: if yeast cells are seen by microscopy, a Sabouraud agar plate can be added to detect Candida.
Microbiological Diagnosis of Bacterial Diseases
Nancy Khardori in Bench to Bedside, 2018
Once the CSF specimen arrives in the laboratory, its gross appearance should be examined. Wet mount of the centrifuged CSF sample should be immediately viewed under compound microscope. The microbiologist must report the number of WBCs, RBC, bacteria and yeast cells. Dark ground microscope should be used in suspected cases of leptospirosis. After the cell count the CSF should be centrifuged to get deposits of cells and bacteria. From the deposit a smear should be made for gram stain and culture should be done with aseptic precautions. Since the number of bacteria in the CSF is low, one should make a heaped up smear without spreading followed by air drying. The smear should be fixed with heat or alcohol. Any bacteria in the gram-stain are considered significant. The report of gram stain of CSF should be made immediately available to the clinician. Simultaneously CSF and serum should also be tested for the bacterial antigens and cryptococcal antigen. The deposits should be cultured on the solid agar plates like blood agar, MacConkey agar and other special agar plates in case of fastidious organisms. Scarping from the petechial rash can show organisms on gram stain in meningococcal disease.
Proteus
Dongyou Liu in Handbook of Foodborne Diseases, 2018
One significant biologic characteristic of Proteus rods is the ability to swarm on surfaces like agar (Figure 36.1). Differentiation of P. mirabilis to the swarming stage has been studied most extensively. Swarming is a cellular differentiation phenomenon that allows a population of bacteria to migrate on a solid surface in a coordinate manner [11]. It is important in the movement of Proteus rods to colonize new locations, including macroorganisms. It involves cell-to-cell signaling and multicellular interactions and is connected with the morphological differentiation of bacteria depending on growth media. When grown in liquid media, Proteus are seen as dimorphic bacteria, mobile, peritrichously flagellated short rods with a longitude of 1.5–2.0 μm and with 6–10 flagella. These bacteria are called swimmer cells. However, when transferred onto solid media like agar, these short rods change into elongated cells (20–80 μm in length). These are hyperflagellated, multinucleated, and nonseptated swarmer cells [12]. This process of differentiation of Proteus bacteria is cyclic. It results in the formation of characteristic rings of bacterial growth on the agar plate [13]. Since it is a process that occurs over the population of Proteus bacteria, the differentiation from swimming cells to swarming cells is induced by the contact of bacteria with a solid surface and the inhibition of flagellar rotation. Belas et al. found that the addition of thickening agents to liquid media stimulates the differentiation to swarmer cells, and the same effect generates the addition of antiflagellar antibodies [14]. Lipopolysaccharide (LPS) and Proteus O-specific polysaccharides are important for the swarming, but the exact role has not yet been determined [15].
Grape seed extract-soluplus dispersion and its antioxidant activity
Published in Drug Development and Industrial Pharmacy, 2020
R. Rajakumari, Tatiana Volova, Oluwatobi Samuel Oluwafemi, S. Rajesh Kumar, Sabu Thomas, Nandakumar Kalarikkal
The GSE-SOLU solid dispersion was tested for antimicrobial activity by agar well diffusion method against pathogenic bacteria Proteus sp, Staphylococcus aureus, Escherichia coli and Bacillus sp. Luria Bertani Agar medium was used to cultivate bacteria. The agar plate surface is inoculated by spreading a volume of the microbial inoculum over the entire agar surface. Fresh overnight culture of each strain was swabbed uniformly onto the individuals plates using sterile cotton swabs. Then, a hole with a diameter of 6 mm is aseptically punched with a sterile borer and a measured volume of the GSE-SOLU at desired concentration is introduced into the well. 3 wells were made on each Luria Bertani Agar plates. Then the centrifuged solution 5 µl of streptomycin (standard), pure GSE, GSE-SOLU solid dispersion, were poured into each well on all plates and incubated for 24 h at 37 °C. After incubation the different levels of zonation formed around the well was measured.
Effect of a bacteriocin-producing Streptococcus salivarius on the pathogen Fusobacterium nucleatum in a model of the human distal colon
Published in Gut Microbes, 2022
Garreth W. Lawrence, Niamh McCarthy, Calum J. Walsh, Tais M. Kunyoshi, Elaine M. Lawton, Paula M. O’Connor, Máire Begley, Paul D. Cotter, Caitriona M. Guinane
S. salivarius DPC6993 was cultivated under anaerobic conditions at 37°C in brain heart infusion (BHI, Difco Laboratories, Detroit, MI, USA) broth and medium. Agar of concentration 1.5% w/v was added for agar plates. F. nucleatum DSM15643 was the target organism used in this study. F. nucleatum DSM15643 was cultivated under anaerobic conditions at 37°C on fastidious anaerobe agar (FAA; Lab M, Lancashire, UK) supplemented with 7% defibrinated horse blood (Cruinn, Dublin, Ireland) and Wilkin–Chalgren Broth (WCB; Oxoid, Hampshire, UK). Both strains were grown anaerobically using anaerobic jars, Anaerocult A gas packs (Merck, Darmstadt, Germany) and a Don Whitley Anaerobic workstation (nitrogen 85%, carbon dioxide 5%, hydrogen 10%). All strains used in this study were grown at 37°C. For a full list of bacteria and their culture conditions used in the antimicrobial spectrum analysis, see Table S1.
Identification and characterization of a locus putatively involved in colanic acid biosynthesis in Vibrio alginolyticus ZJ-51
Published in Biofouling, 2018
Xiaochun Huang, Chang Chen, Chunhua Ren, Yingying Li, Yiqin Deng, Yiying Yang, Xiongqi Ding
The bacterial strains and plasmids used in this study are listed in Table 1. V. alginolyticus ZJ-51 was grown on TSB (Huankai, Guangzhou, China) at 30°C. E. coli strains were grown on LB broth (Invitrogen,Carlsbad, CA, USA) at 37°C. Plates used for colony morphology test, such as TCBS (Huankai), TSB (1% agar added to TSB), LBS (1% agar and 2% NaCl added to LB) and 2216E (Becton Dicknson and Company, NJ, USA) agar plates, were prepared. Soft agar plate (LBS plus 0.3% agar) was used for motility tests. Biofilm growth medium (BFM) used for biofilm formation tests consisted of M63 (3 g l−1 KH2PO4, 7 g l−1 K2HPO4, 2 g l−1 (NH4)2SO4, and 5 mg l−1 FeSO4), 15 g l−1 casamino acids, 10 g l−1 NaCl, 4 g l−1 glucose, 2 mM MgSO4 and 5 mg l−1 thiamine. Chloramphenicol (20 μg ml−1) and IPTG (1 mM) were added to the medium when needed.
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