Sterile sampling techniques and proper handling of the specimen during handling and transport of samples are required to avoid contamination. Pseudomonas aeruginosa is an opportunistic pathogen that infects burns, wounds, surgical incisions and sites of catheterization. Burkholderia mallei produces several acyl-homoserine lactones (acyl-HSLs) which serve as quorum-sensing signals (Ulrich etal. Pseudomonas aeruginosa is a common encapsulated, gram-negative, aerobic-facultatively anaerobic, rod-shaped bacterium that can cause disease in plants and animals, including humans. Human infection has occurred rarely and sporadically among laboratory workers and also those in direct contact with infected, domestic animals. 13525 . Nel 1956 lo studioso M. Dransfiel del dipartimento di Botanica dellUniversit di Nottingham (Inghilterra), piastrando del percolato di suolo sul terreno di coltura Potato Dextrose Agar (PDA), per verificare gli effetti di trattamenti chimici sulle popolazioni fungine del suolo, scopr alcune colonie batteriche che avevano prodotto un pigmento inaspettato, di colore verde-blu. Flagella provide motility and act as adhesins to mucin and respiratory epithelial cells. This pathogen is a facultative intracellular bacterium which has a wide host range, including humans, horses, sheep, goats, dogs, cats, cattle, and pigs. Antimicrobial Stewardship: How the Microbiology Laboratory Can Right the Ship. The bacterium is capable of intracellular survival. Pls what is the colour of salmonella spp on MacConkey agar. Transmission occurs from infected animals via contaminated food and water and less commonly from aerosols and infection of wounds. Ps. Stenotrophomonas maltophilia is readily isolated from water, soil and sewage. It was stored in the refrigerator. [10] Pseudomonas putida is a aerobic, gram negative, rod shaped bacteria. It has emerged as an opportunistic pathogen in animals and immunocompromised humans. Pseudomonas aeruginosa is classified as a member of the fluorescent pseudomonad group which produce pyoverdin. After overnight incubation at 37C, check the growth of the organisms and colony morphology. A seconda dell'intensit della fermentazione si possono distinguere vari gruppi di batteri: Batteri come Pseudomonas aeruginosa e dei generi, Proteus, Edwardsiella, Shigella e Salmonella danno colonie incolori o trasparenti (anche se raramente pu non essere cos). MacConkey agar is a selective and differentiating agar that only grows gram-negative bacterial species; it can further differentiate the gram-negative organisms based on their lactose metabolism. It is the most common cause of infections of burn injuries and of the outer ear (otitis externa). Neutral red is a pH indicator that turns from off-white to bright red/pink as the pH drops below 6.8. Capaci di produrre una vasta quantit di enzimi, proteasi, lipasi e lecitinasi, in grado di alterare le caratteristiche organolettiche degli alimenti, tali batteri rappresentano una causa importante delle alterazioni alimentari. Comprovata esperienza in tecniche analitiche per la ricerca di indicatori di igiene di processo e sicurezza (alimentare e ambientale). Another feature associated with Pseudomonas is the secretion of pyoverdin (fluorescein, a siderophore . putida (6). Asante sana (thank you much) for your post. They do not ferment carbohydrates but do oxidize monosaccharides such as glucose and xylose, but not maltose. Some strains of Proteus may swarm on this medium. Stenotrophomonas maltophilia is readily isolated from water, soil and sewage. P. koreensis was first isolated from Korean agricultural soils. Functions Download Genome Learn about our Enhanced Authentication Initiative. This organism is unable to survive in the environment for more than two weeks. Studies have indicated that virulence of selected B. pseudomallei isolates is variable and dependent on factors such as iron bioavailability, inoculum size and host risk factors (Ulett etal. 18.5) will enhance pyocyanin production and Pseudomonas agar F (BD Diagnostics) enhances pyoverdin production (Fig. [3] MAC is one of the widely used growth media as it can work to selectively grow gram-negative bacteria and further differentiate them based on their fermentation profile. The skin form is also characterized by the formation of tubercle-like nodules, usually along the cutaneous lymphatics, which frequently ulcerate. Cultivation on TSI (Hajn) Agar A triple sugar iron agar (TSI) tube inoculated with Pseudomonas aeruginosa and incubated at ozaenae, Staphylococcus pettenkoferi, Pasteurella pneumotropica, Achromobacter species, Pasteurella aerogenes, Moraxella species and Pseudomonas species. Koneman's - Testo-atlante di microbiologia diagnostica, https://it.wikipedia.org/w/index.php?title=Agar_MacConkey&oldid=119914414, licenza Creative Commons Attribuzione-Condividi allo stesso modo, batteri fortemente fermentanti il lattosio che producono colonie rosse con un'area circostante di precipitazione dei sali biliari (ad esempio, batteri fermentanti il lattosio seguendo la via 2,3-butilenglicole producono colonie rosse senza la precipitazione dei sali biliari (ad esempio, batteri debolmente fermentanti il lattosio che formano colonie che possono apparire, dopo 24 ore, incolore per poi diventare lievemente rosate tra le 24 e le 48 ore (ad esempio. The disease can be acute or chronic and many infections are fatal if not treated at an early stage. 2001). Zoonotic transmission has not been documented. These bacteria are environmental microorganisms typically found in water, soil, on plants, fruits and vegetables. and . The genus Stenotrophomonas has one species of clinical veterinary significance, S. maltophilia (formerly Pseudomonas maltophilia or Xanthomonas maltophilia) (Versalovic 2011). Therefore, lactose-fermenting-gram-negatives (lactose-fermenters) will form pink colonies, while non-lactose fermenters will form off-white opaque colonies. Analista presso impianto di potabilizzazione dell'acqua. Members of the Pseudomonas, Burkholderia and Stenotrophomonas genera grow in broth blood culture systems within the five-day standard incubation guideline. This organism is unable to survive in the environment for more than two weeks. Direct microscopy from specimens is of little diagnostic use as Pseudomonas, Burkholderia and Stenotrophomonas are medium-sized, Gram-negative rods with no other distinctive characteristics. When bacterial gastroenteritis is suspected, the patient's specimen can be sampled and cultured on a panel of bacterial cultures, which includes MacConkey medium. Ps. Austin Community College,5930 Middle Fiskville Rd.,Austin, Texas, ASM Microbe Library:MacConkey Agar Plates Protocols, Thermo Fisher Scientific Inc.,Dehydrated Culture Media: MacConkey Agar, HiMedia Laboratories Pvt. Stenotrophomonas species tend to be straight and slightly smaller (0.40.7m 0.71.8m). This gives McConkey agar its differentiating property. LPS is involved in adherence and invasion and its lipid A part mediates inflammation and tissue damage. Allow the plates to warm at 37C or to room temperature, and the agar surface to dry before inoculating. Flagella provide motility and act as adhesins to mucin and respiratory epithelial cells. MacConkey Agar Is Selective for Non-fastidious Gram-negative Organisms Therefore, MacConkey needed a way to limit this background of environmental flora and allow only his organisms of interest to grow. Suspend 45.3g of Pseudomonas Cetrimide Agar in 1 litre of distilled water. These may also be atypical in certain biochemical reactions, making them difficult to identify. Burkholderia pseudomallei is the aetiological agent of melioidosis, a disease in which treatment failures and relapses are common, with pneumonia as the most common clinical presentation. Lactose monohydrate is the fermentable source of carbohydrate. This allows only gram-negative species to form colonies on MAC agar. Strain variations may determine whether suppurative or granulomatous lesions predominate. These may also be atypical in certain biochemical reactions, making them difficult to identify. P. aeruginosa, P. stutzeri, P. oryzihabitans; Figure 181-1) or more polar flagella (e.g. The diagnostic potential is immense. 2001). The type III secretion system consists of bacterial proteins which act as a syringe to deliver cytotoxins into the cytoplasm of host cells. The type III secretion system consists of bacterial proteins which act as a syringe to deliver cytotoxins into the cytoplasm of host cells. Some strains produce all four pigments. Pseudomonas fluorescens, present in soil and water, is associated with food spoilage and lesions in reptiles and fish (Sakai etal. MacConkey agar is a selective and differentiating agar that only grows gram-negative bacterial species; it can further differentiate the gram-negative organisms based on their lactose metabolism. fluorescence. The selective action of this medium is attributed to crystal violet and bile salts, which are inhibitory to most species of gram-positive bacteria but not all. A major function of this secretion system is to secrete virulence-associated proteins into target cells of the host organism. Pseudomonas, Burkholderia and Stenotrophomonas species The Final Screening Assessment for the Pseudomonas fluorescens strain ATCC 13525 was published in February 2015 under the Chemicals Management Plan (CMP). Pyocyanin, a bluish pigment unique to P. aeruginosa, gives the blue-green colour associated with many cultures. However, direct microscopy of Gram-stained smears with B. pseudomallei will often reveal small Gram-negative bacilli with bipolar staining, safety pin appearance. P. aeruginosa occurs in both rough and smooth lipopolysaccharide (LPS) forms (Sadovskaya etal. 2004). Pyorubin and pyomelanin are less commonly produced, develop slowly and are seen best by growing the strains on nutrient agar slants at room temperature for up to two weeks. However, cases of human-to-human transmission have been reported. Based on the physiological characteristic, the bacteria had optimal temperature for growth with the range of 25-35C, optimal pH 7-8, and able to solubilize phosphate, nitrification,. No H2S is produced on XLD medium. A selective medium for B. mallei can be made by adding 1000 units polymyxin E, 1250 units bacitracin and 0.25mg actidione to 100mL of trypticase soy agar. In horses, the disease is usually chronic and can be carried for many years before clinical signs appear. Adherence to epithelial cells and invasion, resistance to phagocytosis, serum resistance, and production of proinflammatory cytokines Studies have indicated that virulence of selected B. pseudomallei isolates is variable and dependent on factors such as iron bioavailability, inoculum size and host risk factors (Ulett etal. 1989; Swain etal. fluorescens. The colonies on the cetrimide agar appear dry and flat with a circular circumference and lobular edges. Pseudomonas testosteroni (now Comamonas testosteroni ) MICROSCOPIC APPEARANCE MACROSCOPIC APPEARANCE Some colonies produce water-soluble pigment pyoverdin or pyocyanin that fluoresce white to beige under UV light. Stenotrophomonas maltophilia-associated infection is problematic because many strains of the bacterium are resistant to multiple antibiotics. Siderophores are involved in iron acquisition and promote survival in low-iron conditions such as host tissues. Why pasturella multocida is gram negative bt does not grow on macckonkey agar. Additional key components includecrystal violet dye, bile salts, lactose, and neutral red (a pH indicator). 18.2) and XLD agars. Interestingly, pyocyanin can colour pus and stain wool a greenish blue. Burkholderia mallei is a host-adapted pathogen, causing glanders (pulmonary and nasal forms) or farcy (the skin form) in the Equidae population. Is it possible to get a colorless bacterial lawn of E. coli on Macconkey agar? I batteri che non fermentano il lattosio, invece, formano colonie trasparenti od incolori. It is easily killed by desiccation, sunlight and common disinfectants. Burkholderia mallei once had a wide geographical distribution but now is mainly seen in China and Mongolia with pockets of infection in India, Iraq, Turkey and the Philippines. The cultures for P. aeruginosa, B. pseudomallei and B. mallei are incubated aerobically at 3537C for 2448 hours. (1, 6, and 10) Colonial variation includes smooth, soft and shiny (S-forms), dwarf, dry and granular (R-forms) not unlike some colonies of Bacillus species, and mucoid (M-forms) that are frequently biochemically atypical. Check turbidity and subculture on solid media like blood agar and MacConkey agar. Il nome P. The disease usually occurs in tropical regions between 20 northern and southern latitudes but melioidosis has been reported in localized areas of France, Iran, China and the USA. The typical lesions are nodules which may suppurate and can form in any tissue, including the brain. Strain variations may determine whether suppurative or granulomatous lesions predominate. Pseudomonas are aerobic, rod-shaped, motile, non-spore-forming flagellated (one or more polar flagella), gram-negative bacteria. Ps. This gives sticky, wet-appearing colonies. As P. aeruginosa is resistant to many antimicrobials, it frequently causes infection in animals undergoing antibiotic treatment or in immunocompromised hosts. University of Horticultural Sciences, Bagalkot, Karnataka, India. MacConkey agar (MAC) is a bacterial culture medium named after bacteriologist Alfred T. MacConkey (1861-1931). MacConkey agar with bile salt- Selective for gram-negative bacteria but . Pseudomonas fluorescens is one such proven biological control agent. Transmission can also occur via arthropod bites. Composition of MacConkey Agar Final pH 7.1 +/- 0.2 at 25 degrees C. Principle of MacConkey Agar Pancreatic digest of gelatin and peptones (meat and casein) provide the essential nutrients, vitamins and nitrogenous factorsrequired for growth of microorganisms. Incubation of MacConkey Agar plates under increased CO2has been reported to reduce growth andrecovery of a number of strains of Gram-negative bacilli. Laboratory Diagnosis Genus Characteristics Sterilize by autoclaving at 15 lbs pressure (121C) for 15 minutes. The incubation period is frequently prolonged and disease signs may appear months or even years after infection. Nei soggetti immunodepressi, P. fluorescens pu annidarsi nel tratto orofaringeo e dare infezioni post-trasfusionali e respiratorie. This makes MAC a powerful tool in differentiating and isolating bacterial species from the sample source. 18.2) and XLD agars. Malleobactin is a siderophore involved in iron acquisition (Alice etal. Macconkey agar is Known to he the selective media for culturing Gram negative bacteria and some of Gram positive bacteria;so for that case staphylococcus gives pale pink color in M.A because it is able to grow in this medium. They are opportunistic pathogens of animals, humans and plants. Pseudomonas (green rot) (pink rod) (black rot) (colorless rot) Pseudomonas fluorescens . document.getElementById("ak_js_2").setAttribute("value",(new Date()).getTime()). Both of these species have been identified as potential agents of bioterrorism (category B biothreat agents). 2001) and one of the factors facilitating its persistence in the body. Pseudomonas fluorescens, present in soil and water, is associated with food spoilage and lesions in reptiles and fish (Sakai etal. MacConkey agar is designed to grow Gram-negative bacteria and also contains crystal violet dye which inhibits the growth of Gram-positive bacteria. 1989; Swain etal. Pseudomonas aeruginosa on tryptic soy agar. Commercial selective media are available for P. aeruginosa and usually contain cetrimide, acetamide, nitrofurantoin, or 9-chloro-9(4-diethylaminophenyl)-9,10-dihydro-10-phenylacridine hydrochloride. Pseudomonas un genere di batteri appartenenti alla famiglia delle Pseudomonadaceae.Il nome significa falsa unit (dal greco: , pseuds, "falso" e , mnos, "singola unit"); deriva dalla abitudine di questi batteri a disporsi a coppie di cellule che osservate al microscopio sembrano una sola cellula.Alcuni microbiologi lo battezzarono cos all'inizio del XX secolo Pili are the major adhesins implicated in the initial attachment phase to host tissues. Pseudomonas and Stenotrophomonas can be handled in a biosafety level-2 laboratory. Pseudomonas aeruginosa on Deoxycholate Citrate Agar (lactose negative, H 2 S negative). Burkholderia mallei and B. pseudomallei are among the most dangerous bacteria to work with in a laboratory. Pseudomonas, Stenotrophomonas and Burkholderia species have a worldwide distribution. The culture was isolated from pre-filter tanks and has applications in bioinformatics, water testing, and antimicrobial preservative testing. Damage to host tissues, cytotoxic, implicated in invasion process Table 18.1 P. fluorescens, P. putida, P. luteola). Besides P. fluorescens and A. baumannii other isolates identified include Vibrio and Myxobacteria. Nurses arefrequently involved in obtaining and transporting samples from the patient to the laboratory. Assistant Professor of Agricultural Microbiology, Cool the medium to approximately 50C and pour into sterile Petri dishes. Pseudomonas (dal gr. Human disease cases can present as localized, suppurative cutaneous infections, pulmonary infections, bloodstream infections or suppurative chronic infections of the skin. Pseudomonas pseudomallei - Another environmental inhabitant - Blood Agar - cream to yellow-orange; smooth and mucoid to dry and wrinkled and exhibits putrid odor - MacConkey Agar - NLF; but exhibits pink-colonies as it oxidixes lactose - Ashdown medium - NLF; dry, wrinkled, and violet-purple - Causative agent of melioidosis, also known as Whitmore's disease, which is an infectious . Pasteurella species (including Pasteurella multocida) will not grow on MacConkey Agar. Save my name and email in this browser for the next time I comment. I salute you for the nice explanations in Microbiology you regularly upload in Facebook. 28.2: Pseudomonas aeruginosa on nutrient agar showing greenish . The disease is characterized by a high fever, with respiratory clinical signs such as swollen nostrils, catarrhal nasal discharge, lymphadenopathy, dyspnea, and pneumonia. A number of saprophytic Pseudomonas species and Burkholderia species have been implicated in occasional infections of animals (Jackson & Phillips 1996, Berriatua etal. Dear Sir, Lactose fermentation will produce acidic byproducts that lower the pH, and this turns the pH indicator to pink. Per l'isolamento di P.fluorescens da campioni alimentari contaminati si utilizza il terreno selettivo Pseudomonas Agar Base (PAB) addizionato con cetramide, fucidina e cefaloridina (CFC supplement). It has emerged as an opportunistic pathogen in animals and immunocompromised humans. Related You may also needAeromonas, Plesiomonas and Vibrio speciesBacillus speciesErysipelothrix speciesMiscellaneous Gram-negative bacteriaEnterobacteriaceaeMycobacterium speciesLawsonia intracellularisCampylobacter, Arcobacter and Helicobacter species Pseudomonas spp. Some strains may be encountered that grow poorly or fail to grow on this medium. The growth of B. mallei is enhanced by 1% glycerol. Motility, adherence to mucin When pyoverdin is combined with pyocyanin, the bright green colour characteristic of P. aeruginosa is expressed. grows only in the presence of oxygen.. There are various culture media used for the cultivation of Pseudomonas aeruginosa (P. aeruginosa) in the laboratory and most commonly the Nutrient Agar medium and MacConkey Agar medium is used, the other media are as follows - Just curious. Buongiorno, MacConkey agar is considered a useful selective medium for the recovery of most of the Pseudomonas species. 18.1). It is likely that variation in simple sequence repeats in key genes provide a mechanism for generating antigenic variation. 2003) including P. fluorescens (septicaemia in rainbow trout and Tilapia and necrotizing hepatitis in pet birds), P. putida (endotoxic shock in a cynomolgous macaque) and B. cepacia, formerly P. cepacia (outbreak of subclinical mastitis in a flock of dairy sheep). Under particular conditions, P. aeruginosa can produce an alginate structure which is a slime-like, mucoid exopolysaccharide. The growth of B. mallei is enhanced by 1% glycerol. Other virulence factors of note include the ability to form a biofilm, adherence and the ability to invade respiratory epithelial cells (Di Bonaventura etal. Preparation of MacConkey agar. document.getElementById( "ak_js_1" ).setAttribute( "value", ( new Date() ).getTime() ); About Us - Contact Us - Privacy Policy & Disclaimer, Benedicts Test- Principle, Composition,, Widal Test- Introduction, Principle, Procedure,, Different Size, Shape and Arrangement of Bacterial Cells, Gram Staining: Principle, Procedure, Interpretation,, Nutrient Agar: Composition, Preparation and Uses, MacConkey Agar- Composition, Principle, Uses,, Catalase Test- Principle, Uses, Procedure, Result, List of culture media used in microbiology with their uses, Salmonella Shigella (SS) Agar- Composition, Principle, Uses, Preparation and Result Interpretation, Xylose Lysine Deoxycholate (XLD) Agar- Principle, Uses, Composition, Preparation and Colony Characteristics, Thiosulfate-Citrate-Bile Salts-Sucrose (TCBS) Agar- Composition, Principle, Uses, Preparation and Colony Morphology. The disease usually occurs in tropical regions between 20 northern and southern latitudes but melioidosis has been reported in localized areas of France, Iran, China and the USA. As P. aeruginosa is resistant to many antimicrobials, it frequently causes infection in animals undergoing antibiotic treatment or in immunocompromised hosts. Its capsular polysaccharide is reported as a major virulence factor (DeShazer etal. As pyocyanin is unique to P. aeruginosa this is an important diagnostic characteristic although strains vary in the amount of the pigment they produce. Sterilize by autoclaving at 15 lbs pressure (121C) for 15 minutes i.e. Thank you so much. P. fluorescens complex isolates have been recovered from many environmental sources, and are frequently associated with plants and soils []. Practical Guidance for Clinical Microbiology Laboratories: Diagnosis of Bacterial Gastroenteritis. Figure 18.1 Pseudomonas aeruginosa on sheep blood agar showing large, flat, irregular-edged colonies resembling those of some Bacillus species. Pseudomonas fluorescens Heavy growth may produce a greenish-gold fluorescent pigment. Iron uptake Predisposing causes include trauma to tissue (burns and wounds), debilitation due to malignancy or immunodeficiency and an imbalance in the normal flora, often caused by antibiotic therapy. In continuo aggiornamento in campo microbiologico. Pseudomonas and Stenotrophomonas can be handled in a biosafety level-2 laboratory. In intensive care units, testing multi-drug resistance in gram-negative bacteria is an important surveillance measure. Lactose-fermenting microorganisms will produce organic acids, particularly lactic acid, which will lower the pH. It is nonsporeforming and is motile by one or more flagella. Mannitol is a fermentable carbohydrate. 2007). Sodium chloride maintains the osmotic balance in the medium. (Lab 4) . Both of these species have been identified as potential agents of bioterrorism (category B biothreat agents). Ramanan P, Bryson AL, Binnicker MJ, Pritt BS, Patel R. Syndromic Panel-Based Testing in Clinical Microbiology. Malleobactin is a siderophore involved in iron acquisition (Alice etal. putida. Primary lesions occur at the point of entry (skin or mucosal surfaces) with dissemination via the lymphatic system and dissemination by the bloodstream. Il riconoscimento delle colonie di P. fluorescens possibile attraverso laiuto di una lampada UV, poich produce siderofori che emettono fluorescenza giallo-verde. Certolizumab Pegol e il suo ruolo contro il TNFa, Obesit in et pediatrica: una patologia da non sottovalutare, 28 febbraio 1953: 70 anni fa la scoperta del DNA, Colonie piatte e rosa con aloni rosa scuro (dato dalla precipitazione dei sali biliari), Colonie rosa senza precipitazione di sali biliari, Parzialmente o completamente inibito. StatPearls Publishing, Treasure Island (FL). Stenotrophomonas species tend to be straight and slightly smaller (0.40.7m 0.71.8m). Human infection has occurred rarely and sporadically among laboratory workers and also those in direct contact with infected, domestic animals. These bacteria are strict aerobes, non-spore-forming, oxidative, catalase-positive, oxidase-positive (except P. oryzihabitans, P. luteola and the genus Stenotrophomonas) and most are motile by one or several polar flagella (except B. mallei). Pseudomonas aeruginosa is a Gram negative, non-sporing motile rod P. aeruginosaproduces large, flat, spreading colonies which are often haemolytic and usually pigment-producing. Standard collection and transport methods are sufficient to ensure the recovery of, Direct microscopy from specimens is of little diagnostic use as, Aeromonas, Plesiomonas and Vibrio species, Campylobacter, Arcobacter and Helicobacter species, Cytotoxic, invasion of tissue and cellular damage, immunosuppressive action, Damage to tissues of the lungs and blood vessels, Tissue damage, stimulation of inflammatory mediators, Siderophores (pyoverdin, pyocyanin, pyochelin), Rhamnolipid (haemolysin with lecithinase activity), Damage to host cell membranes and impaired mucociliary clearance, Type III secretion system (exoenzymes S, T, U and Y), Damage to host tissues, cytotoxic, implicated in invasion process, Protection from phagocytosis, adhesin, antimicrobial resistance, Adherence to epithelial cells and invasion, resistance to phagocytosis, serum resistance, and production of proinflammatory cytokines. Predisposing causes include trauma to tissue (burns and wounds), debilitation due to malignancy or immunodeficiency and an imbalance in the normal flora, often caused by antibiotic therapy. Burkholderia mallei is the causative agent of glanders, a disease of livestock that particularly affects horses, mules, and donkeys (Table 18.1). It starts with a yellow color, but if a species ferments lactose, it will turn the medium pink. Record observations here on the growth and appearance of the three bacteria on MacConkey agar. Nei casi rari in cui infetti luomo, la maggior parte dei ceppi di P.fluorescens sono sensibili alla tetraciclina, agli aminoglucosidi e alle nuove beta-lattamine, ureidopenicilline, carbapenemici, monobattami. 18.5) will enhance pyocyanin production and Pseudomonas agar F (BD Diagnostics) enhances pyoverdin production (Fig. Main diseases caused by the major pathogenic Pseudomonas, Burkholderia and Stenotrophomonas species in veterinary medicine. Humphries RM, Linscott AJ. Gram-negative bacteria, like P. fluorescens, do not retain the primary stain due to their thin cell walls and higher lipid content. Burkholderia mallei is the causative agent of glanders, a disease of livestock that particularly affects horses, mules, and donkeys (Table 18.1). Di y l lng cha vitamine trong mt vi loi vi sinh vt (/g trng lng kh) Enterobacter Pseudomonas Clostridium Torulopin Vitamine acrogenes fluorescens butyricum utilis Acid 249 210 250 500 nicotinic Riboflavin 44 67 55 49 Thiamine 11 26 9 6.2 Piridoxin 7 6 6 - Acid 140 91 93 130 pantotenic Acid folic 14 9 3 2.8 Biotin 4 7 - 1.8 +Enzyme: Nh nhng sinh .