Clinical Bacteriology PDF - Non-Spore Formers

Clinical Bacteriology LECTURE|Module 3- Part 1|Gram positive bacilli (non-spore formers)|1st semester |Prelim Precipitin lines (line of interaction) are formed if the GENUS: CORYNEBACTERIUM...

Clinical Bacteriology LECTURE|Module 3- Part 1|Gram positive bacilli (non-spore formers)|1st semester |Prelim Precipitin lines (line of interaction) are formed if the GENUS: CORYNEBACTERIUM strains are toxigenic. Characteristics: Filter paper strip impregnated with diphtheria and Irregularly, nonparallel sides, club-shaped which is highly antitoxin pleomorphic Can use ELISA, PCR, Immunochromatographic strip Appears as Chinese letter / Palisadine / V / L shape due to assay pleomorphic appearance Normal on skin and mucous membranes 2. Animal inoculation test Other Corynebacterium aside from C. diphtheria is In vivo toxigenicity test referred to as diphtheroids due to its pleomorphic Intraperitoneal injection appearance Positive: Death of animal without antitoxin Facultative anaerobe Catalase (+) 3. Schick’s Test No growth in MAC agar Skin test for diphtheria Positive: Inflammation at the site of the injection Corynebacterium diphtheriae Kleb Loeffler’s Bacillus 4. Vero Cell Cytotoxicity Assay Narrow hemolysis on BAP Gold standard for toxin production DNase test (+) Causative agent: Diphtheria Corynebacterium diphtheriae: TREATMENT AND PREVENTION Have palisading appearance due metachromatic granules Treatment ○ Babes Ernst Granules- Black appearance Penicillin (drug of choice) or Erythromycin- Inhibits the growth. Corynebacterium diphtheriae: CLINICAL INFECTIONS Diphtheriae Anti-P-toxin- Given thru IV. Public health concern Prevention DPT Vaccine 1. Diphtheria ○ Can prevent three bacteria: (1) Diphtheria, (2) Virulence factor: Diphtheria toxin (heat labile Pertussis known as whooping cough, (3) Tetanus polypeptide that is absorbed in the mucous membrane) ○ Given during infancy Symptoms: ○ Pseudomembrane formation or bull’s neck UREASE NITRATE FERMENTATION LIPOPHILIC appearance REDUCTION OF GLYCOGEN ○ Low grade fever C.diphtheria ○ Sore Throat Var gravis - + + - ○ Malaise C.diphtheria - + + - Site of Infection: Epithelial cells surrounding tonsils, Var mitis pharynx, or larynx C.diphtheria - - - - Toxin once released will cause inflammation and later Var belfanti necrosis leading to pseudomembrane formation C.diphtheria - + + + Var Corynebacterium diphtheriae: CULTURE MEDIA intermedius 1. Cystine Tellurite Blood Agar (CTBA) Selective culture media OTHER Corynebacterium spp. Potassium tellurite - Inhibitory substance Corynebacterium jeikeium Positive: Gray to black colonies JK Bacillus Virulent organism (antibiotic resistance) 2. Tinsdale Media Gamma hemolytic & strict aerobe Positive: Black colonies with brown halo Produce metallic sheen on surface of BAP 3. Loeffler’s serum and PAI’s coagulated egg serum Hospital acquired pathogen Enhances pleomorphism and granule formation of C. ○ Causes endocarditis diptheriae Infection through implantation of prosthetic devices Corynebacterium diphtheriae: LABORATORY TESTS Corynebacterium ulcerans 1. Elek / Ouchterlony / Frobisher Test Bovine mastitis Immunodiffusion technique to determine of the Human acquire it after exposure to infected cattles or infection is toxigenic or not contaminated milk products Toxin Formation Test  Clinical Bacteriology LECTURE|Module 3- Part 1|Gram positive bacilli (non-spore formers)|1st semester |Prelim Corynebacterium urealyticum GENUS: LISTERIA Urinary pathogen that is slow growing (48 hours) Lipophilic Corynebacterium- Better growth in broth with Listeria monocytogenes rabbit’s serum Agent of human and animal listeriosis Strongly urease (+) Can survive and grow in 4°C (Psychrophiles or cold loving) Cause encrusted cystitis & pyelonephritis Can survive and grow in low pH Can tolerate high salt condition Corynebacterium amycolatum Can be isolated in soil, water, vegetation, and animals Most common diphtheroid from human materials Associated with contaminated food from the refrigerator Associated with prosthetic joint infection Can spread transplacentally Corynebacterium pseudodiphtheriticum Listeria monocytogenes: VIRULENCE FACTORS Hoffman’s Bacillus Normal flora: Throat 1. Hemolysin (Listeriolysin O) Pathogen in heart, can cause endocarditis Hemolytic and cytotoxic toxin that damages the phagosome membrane (damage RBC and cells) Corynebacterium minutissimum 2. Protein p60 Produce coral red fluorescence due to porphyrin in wood’s Induces phagocytosis thru increase adhesion and lamp penetration into mammalian cells Erythrasma- Skin infection affecting axillary and pubic skin. Causes human & animal listeriosis NOTES: Listeria monocytogenes: CLINICAL INFECTION Erythrasma- Corynebacterium minutissimum Human and Animal Listeriosis Erysipeloid- Erysipelothrix rhusiopathiae Erysipelas- Streptococcus pyogenes 1. Pregnant women Stillbirth and spontaneous abortion due to bacterial BIOCHEMICAL IDENTIFICATION FOR infection CORYNEBACTERIUM Low survival rate for babies LIPOPHILIC BETA HEMOLYSIS CAMP NITRATE REDUCTION UREASE ACID FROM ACID FROM 2. Newborn GLUCOSE MALTOSE Bacteremia (leads to Granulomatosis infantiseptica and C. diphtheriae V V - + - + + late onset) C. Granulomatosis infantiseptica - - - V - + V amycolatum ○ Early onset syndrome ○ Result of infection in utero C. jeikeium + - - - - - V ○ Abscess C. - - REVERSE + + - - ○ Formation of granuloma Pseudodiph- ○ Pustular lesions containing bacteria theriticum ○ Death C. pseudo Late onset syndrome - + - V + + + tuberculosis ○ Can cause meningitis and meningoencephalitis ○ Associated with sepsis C. ulcerans - V REVERS + + + + Meningitis C. + - - - + - - urealyticum 3. Immunosuppressed Host Meningitis and endocarditis S. pneumoniae- Causes meningitis (5-29 years old adult) Haemophilus influenzae- Causes neonatal meningitis Neisseria meningitidis- Causes meningitis (toddlers) NOTE: Number 3 is not part of the recording. Clinical Bacteriology LECTURE|Module 3- Part 1|Gram positive bacilli (non-spore formers)|1st semester |Prelim Listeria monocytogenes: LABORATORY DIAGNOSIS GENUS: ERYSIPELOTHRIX 1. Microscopy Gram (+) rods or coccobacilli in pairs or in short chains Erysipelothrix rhusiopathiae Thin, filamentous gram (+) rods 2. Cultural Characteristics Arrange singly, in short chains or V shape Small, round, smooth, translucent Gram variable (appears +/-) Narrow zone of beta hemolysis Erysipelothrix rhusiopathiae: CLINICAL INFECTION 3. Identification Erysipeloid Grows best at 30°C - 35°C (psychrophilic or cold ○ Occupational hazard for butcherist (fish, raw meat) loving) or can also grow in 0°C to 5°C or at 45°C. ○ Localized painful skin infection Can isolate in placenta and other tissue using cold ○ Work related inoculation enrichment media (Mc Bride media) Specimens: Blood, CSF, lesions (swab) from the abscess Septicemia End over end tumbling motility in nutrient broth ○ Sepsis- Bacterial infection in bloodstream (hanging drop or wet mount room temperature) Umbrella shaped / inverted Christmas tree pattern Diffuse cutaneous infection into a semi-solid tube (22°C to 25°C) (same as ○ Penicillin- Drug of choice for localized or systemic B.anthracis) infection CAMP Reaction Erysipelothrix rhusiopathiae: LABORATORY IDENTIFICATION ○ Block or shovel type or rectangle appearance Best specimen for culture: Biopsy and tissue aspirates from positive enhanced hemolysis is observed erysipeloid lesions ○ Known (y-axis): Rhodococcus equi ○ Unknown (x-axis): Suspected Listeria monocytogenes OXIDASE - CATALASE - Hippurate Hydrolysis Test UREASE - ○ Test for the ability to hydrolyze hippuric acid ESCULIN HYDROLYSIS - [substrate] (Sodium Hippurate) to benzoic acid and GELATIN - glycine H2S + (blackening) ○ Glycine can be detected with ninhydrin reagent ○ Positive: Deep blue to purple; L.monocytogenes ○ Negative: Colorless; Corynebacterium spp. ANTIBIOTIC SUSCEPTIBILITY TEST SUSCEPTIBLE RESISTANT Bile Esculin Test Penicillin Vancomycin ○ Test for the ability of the organism to grow in 40% Cephalosporins Sulfonamides bile and hydrolyze esculin Erythromycin Aminoglycosides ○ Positive: Growth (tolerance to 40% bile and Clindamycin blackening [hydrolysis of esculin]) L.monocytogenes Chloramphenicol ○ Negative: Lack of growth and no color change (no blackening) GENUS: ACTINOMYCETES CATALASE + MOTILITY (+) Tumbling Branching Actinomycetes ESCULIN HYDROLYSIS + Cells forms hyphae (threadlike branching filaments) Only branching gram + bacilli HIPPURATE + Form filaments on the agar surface or extend to the air VP TEST + H2S ON TSI - Clinical Bacteriology LECTURE|Module 3- Part 1|Gram positive bacilli (non-spore formers)|1st semester |Prelim GENUS: LACTOBACILLUS Lactobacillus acidophilus Doderlein Bacillus Produce large amount of lactic acid Normal vaginal flora with little clinical significance Gram (+), non-spore forming rods (pleomorphic rods or coccobacilli) Non-motile, anaerobic bacteria Widely distributed in foods (Lactobacillus casei shirota strain -yakult) Catalase (-) Tomato Juice Agar (can give low pH) - Cultivation of lactobacilli Normally found in PAP-stained smear (screening test for cervical cancer) CATALASE MOTILITY ESCULIN ACID FROM UREASE H2S HYDROLYSIS GLUCOSE PRODUCTION Corynebacterium + - V V V - L. monocytogenes + + + + - - E. rhusiopathiae - - - + - + R. equi + - - + - Gardnerella vaginalis One of the causes of bacterial vaginosis Catalase (-), NSF Short, pleomorphic gram variable Gram staining of vaginal secretions is generally regarded as the reference method for diagnosing BV Observation of “clue cells”- Large squamous epithelial cells with gram (+) and gram variable bacilli & coccobacilli clustered on the edges Specimen: Vaginal Secretions Tests: Gram staining and amine test Culture media: Human Bilayer Tween Agar Mobiluncus spp. is also one of the causes of BV