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68 Cards in this Set
- Front
- Back
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all Neisseria species are what? |
-aerobic gram neg diplococci -oxidase & catalase pos -fastidious -capnophilic -normal flora of mucous membranes of respiratory & urogenital tracts (opportunistic speicies) |
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what is capnophilic? |
-require moist environment |
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who are the only nature host for nesseria gonorrhea ? |
-humans are the only natural host |
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where do gonococcal infections occur most commonly? |
-urethra, endocervix, anal canal, pharynx, & conjunctiva |
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how are gonococcal infections most commonly transmitted |
-most commonly transmitted by sexual contact |
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what are the virulence factors of gonorrhea? |
-capsule -pili ( T1-T5) -cell wall proteins: I, II, III -lipopolysaccharide (endotoxin) -IgA protease that cleaves IgA on mucosal surfaces -iron acquisition system |
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how many morphology distinct colony types are there? |
-5 colony types (T1-T5) |
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what are the 5 morphology distinct colonies based on? |
-the presence or absence of pili |
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why are pili important? |
-important in the initial attachment to host tissues & to inhibit phagocytosis |
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what are types T1 and T2 |
-pili + -virulent forms |
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what are types T3-T5? |
-pili - -avirulent forms |
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capsule |
-prevents phagocytosis |
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PI (POR) |
-outer membrane porin -inhibits the ability of phagocytes to kill ingested bacteria |
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PII (Opa) |
-mediates tight binding to epithelial cells & invasion -important for cell to cell signaling -causes the colonies to appear opaque |
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PIII ( Rmp) |
-protects other surfaces Ags from Ab attack |
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what does the iron acquisition system do? |
-mediates acquisition of iron for bacterial metabolism |
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what are the transferrin recptors |
-Tbp1 and Tbp2 |
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lactoferrin receptor |
-Lbp |
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pathogenesis |
-gonococci attach to mucosal cells, penetrate into the cells & multiply -then pass through the cells into the subepithelial space, where infection is established |
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gonorrhea in the male is primarily restricted to where? |
-urethra |
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how long is the incubation of gonorrhea in males? |
-short, 2-7 days |
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what are some symptoms and complications apparent in males with gonorrhea? |
-presents with purulent uretheral discharge -Asymptomatic infection is uncommon-95% show acute symptoms -complications: ascending infections |
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what is the primary site of gonorrhea in females? |
-endocervix |
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symptoms in females with gonorrhea |
-up to 50% asymptomatic -symptoms: discharge, dysuria, abdominal pain
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gonorrhea in females is the major cause of what? |
-pelvic inflammatory disease (PID) -ascending |
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complications of gonorrhea in females? |
-sterility -ectopic pregnancy -perihepatitis (fitz-hugh-curtis-syndrome) |
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disseminated infections |
-occurs in less than 1% of infections most common in females |
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anorectal and oropharyngeal infections are most common in who? |
-homosexual males |
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opothalmic neonatorum |
-newborn eye infection -can result in blindness -treated with silver nitrate drops |
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specimen of choice for genital infections from males & females? |
-urethra: males -endocervix: females - the discharge |
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JEMBEC plate |
-generates CO2 via NaHCO3 tablet -special streaking technique |
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Gram stains from urogenital specimens |
-gram negative intracellular diplococci -culture needed to be confirmed |
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what is the most commonly used selective media? |
-Modified Thayer Martin (MTM) |
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Incubation: |
-media should be at room temp -neisseria is susceptible to cold -incubated at 37C CO2 incubator |
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Microscopic examination of gonorrhea |
-gram neg, kidney shaped diplococci
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colonial morphology of gonorrhea |
-small, gray, translucent, and raised |
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why should gonorrhea be subcultured frequently |
-can produce autolytic enzymes -every 24 to 48 hours |
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gonorrhea tests positive for what test? |
-oxidase |
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Cystine trypticase agar (CTA) |
-contains 1% carbohydrate -phenol red as pH indicator -yellow color indicates usage (oxidative) |
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what is a common way to differentiate different neisserias? |
-use a battery of four sugars: glucose, maltose, lactose, and sucrose -requires pure colonies, & viable organisms |
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immunologic methods do not require.... |
-viable organisms -so can be done from primary plates |
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coaggultination |
-monoclonal abs attached to carrier particle |
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fluorescent anitbody (FA) |
-monoclonal ab that recognizes epitopes on PI -extremely specific -ELISA
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Nuclei Acid probe test does what? |
-amplifies DNA by PCR then uses chemilumnescent DNA probe |
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what is nuclei acid probe test best used for? |
-urogenital specimens
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nuclei acid probe test |
-expensive -special swabs -usually done in combination for chlamydia |
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what are two mechanisms of resistance? |
-plasmid mediated -chromosome mediated mutations |
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plasmid mediated |
-beta lactamase production -tetreacycline resistance |
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chromosome mediated mutations |
-spectinomycin resistance |
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what are the virulence factors for Neisseria meningitidis? |
-pili -capsule -LPS endotoxin -IgA protease |
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who most often gets meningitis? |
-young adults
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what is the mortality rate for meningitis? |
-25% mortality rate |
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symptoms of meningitis |
-abrupt onset of frontal head ache, stiff neck -petichial skin lesions may develop with bacteremic spread---thrombosis common -death may occur 12-48 hours from on set |
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what are the effects of capsule & LPS shedding? |
-disseminated intravascular coagulation -hypovolumic shock |
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meninges |
-composed of 3 layers of membranes enclosing the brain and spinal cord
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pia mater |
-inner most -adheres to brain & spinal cord |
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arachnoid mater |
-middle layer |
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dura mater |
-outer most layer -adheres to skull and spinal canal |
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why are bacteria able to cross the blood brain barrier? |
-no white blood cells there -able to grow rapidly |
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when the immune system responds to meningitis what happens? |
-sends out chemical signals that produce inflammation causing the meninges to swell -increased pressure inside skull -disruption of brain function |
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Diagnosis of meningitis |
-CSF gram stain: STAT -culture on blood or chocolate plates -oxidase & catalase + -CTA sugars -immunologic methods
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what is moraxella catarrhalis formerly known as? |
-branhamella catarrhalis |
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what is moraxella catarrhalis? |
-normal commensal of respiratory tract |
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moraxella catarrhalis: test & plates |
-BAP or chocolate agar -oxidase & catalse + -asaccharolytic -DNase & Butyrate esterase + |
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how can you be exposed to m.catarrhalis? |
-respiratory droplet -normal flora in mouth
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how is m.catarrhalis replicated & spread? |
-replicated in the oropharynx -opportunistic pathogen |
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what type of damage does m.catarrhalis cause? |
-inflammation |
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Moraxella virulence factors |
-pili: adherance -LPS (lipopolysaccharide) |
