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89 questions
| 🇬🇧 | 🇬🇧 |
| Stain-hot method Mycobacteria appear red (carbol-fuchsin) while other microbes, tissue appear blue (methylene blue) | Ziehl-Neelson (ZN) |
| - Low resistance – Nerves, skin, eyes, nose, mouth etc. damaged – Bacteremia • liver, spleen, BM involved | Lepromatous leprosy |
| Presence of aerial hyphae and acid fastness | How to test for its Nocardia's presumptive identification? |
| Nocardia | Gram stain of which bacteria? |
| Neisseria | Unique Small Gram –ve diplococci Oxidase positive Grow best at 35-37°C, humid CO2 Environment N.Gonorrhea and N.Menigitidis |
| Why does a vaccine exist for N. meningitidis but not N. gonorrhoeae? | N. meningitidis Capsular proteins are used as vaccine N. gonorrhoeae does not have a true capsule Surface proteins of N. gonorrhoeae have not been useful for production of a vaccine |
| N. gonorrhea | Gram -ve diplococci Oxidase +ve Cannot grow on nutrient Agar Humans are only natural host 2nd to chlamydia as most common sexually transmitted disease Transmitted primarily by sexual contact Die rapidly if specimen dries |
| What is the major reservoir of N.gonorrhea? | Asymptomatic infected woman (men |
| N. meningitidis | Gram -ve diplococci Oxidase +ve mortality rate close to 100% (10% if treated quickly and correctly) transmitted by respiratory droplets among people in prolonged close contact Variable growth on nutrient agar |
| Eikenella corrodens | Small, nonmotile, non-spore forming, gram –ve rods Blood/chocolate agar Capnophilic: 5-10% CO2 Bleach like odor Transmission: bite from infected person (introduction of organism into deep tissue) |
| Kingella kingae | Gram –ve fastidious, oxidase +ve coccobacilli Resemble Neisseria and reside in oropharynx Septic arthritis in children (2nd to S. aureus) and endocarditis |
| Pasteurellaceae family | Haemophilus and Pastereurella |
| Haemophilus | Requires blood for growth on agar H.influenza - originally thought to be the cause of the influensa Differentiation dependent on X or V factor |
| Pasteruella | Facultative anaerobic, fermentative coccobacilli P. multocida (many-killing) P. canis (dogs) Most human infections from animal contact (bites) |
| Pseudomonas | Motile, straight or slightly curved Gram –ve rods, arranged in pairs Aerobic respiration (can use nitrate or arginine as an alternate electron acceptor) Cytochrome oxidase (used to differentiate from enterobacteriaceae) Common in cystic fibrosis patients Produce diffusible pigments for preliminary ID (blue pyocyanin, yellow-green pyoverdin, pyorubin red-brown) |
| P.aeruginosa | Pseudomonas External otitis (swimmer's ear) Malignant external otitis: primarily elderly or diabetic ppl, damages cranial nerves and bones, may be life threatening |
| Acinetobacter spp. | Pseudomonas Strictly aerobic, oxidase -ve, plump Gram –ve, coccobacilli Can survive on moisturized and dried surfaces (unusual for gram -ve) Part of normal oropharyngeal flora Most human infections caused by A.baumannii "Can close clinics faster than inspectors" |
| Campylobacter | Gram -ve comma shaped microaerophilic rods Causes gastroenteritis (most common cause) and septicemia Lab: elevated tem (42 degrees), microaerophilic (5-7% O2 and 5-10% CO2) C.jejuni, C.coli, C.upsaliensis (contact with dogs) |
| Helicobacter | Gram -ve rods Gastic helicobacter and enterohepatic helicobacter |
| Gastric helicobacter | Most important -> H.pylori: gastritis, peptic ulcer and B-cell lymphomas |
| Bordetella | B.pertusis (whooping cough): humans only Inhalation of aerosols Use adhesins to attach to epithelial cells Incubation period: 7-10 days |
| Brucella | Gram -ve, non-fermenting zoonotic (contaminated food, direct contact with infected animal) Non-motile non-encapsulated Facultative or strictly aerobic Complex growth media Predilection for erythritol (breast, uterus, placenta) BSL-3 Antibody detection: IgM initially -> IgG, IgA |
| Legionella | Gram -ve rod (short bacilli) Obligate aerobe Enriched cysteine and iron Dieterle Silver Stain Aerosols |
| Clostridium | Gram +ve rods Produce endospores Diarrhea, colitis and botulism Ladle shaped |
| C. difficile | Diarrhea and colitis Part of normal GI flora Disease develops after 5-10 of antibiotics treatment (kills competitors of c.difficile) Enterotoxin A and B Smells like horse in lab culture ELISA and 16s rRNA (Some strains are known to produce actin – specific ADP-ribosyltransferase (binary toxin) such as ribotypes 027) |
| Which enterotoxin of c.difficile is more toxic? | B Causes actin to depolymerise resulting in disruption of cellular cytoskeleton |
| Clostridium tentani | Gram +ve, motile, spore forming rods Strict anaerobe!! Looks like drumsticks Disease: tetanus Produces toxins that lead to spastic paralysis Neither toxins nor antibodies to the toxin are detectable (toxin rapidly bound to motor neurons and internalized). |
| Clostridium botulinum | Large, fastidious, spore forming Gram +ve anaerobic rods Divided into 4 groups depending on phenotypic and genotypic properties 7 antigenically distinct botulinum toxins (A-G) |
| C.botulinum | A-B toxin: A light chain, B heavy chain (Complex toxin with nontoxic protein that protects the neurotoxin in the digestive tract) Leads to flaccid paralysis Home canned foods Easier to culture if specimens, food or stools are heated @80°C for 10 min to kill non-sporing bacteria |
| What is an exception to the non-spore forming anaerobes? | Bacteroides fragilis |
| Non-spore forming Gram -ve rods | 5 important genera – Bacteroides – Fusobacterium – Parabacteroides – Porphyromonas – Prevotella Predominant bacteria on mucosal surfaces outnumbering Aerobes by 10-1000 fold |
| Bacteroides | B.fragilis Surrounded with a polysaccharide capsule w/o endotoxin activity Growth stimulated by bile Pleomorphic Gram –ve rods Grow rapidly in anaerobic environment |
| Causes syphilis (non-venereal disease) | T.pallidum subsp. pallidum |
| Causes yaws (non-venereal disease) | T. pallidum subsp. pertenue |
| M.hominis (facultative anaerobe with arginine agar media) | Which bacteria looks like fried eggs? |
| Gram -ve Causes Q fever Ingestion of contaminated unpasteurised milk and milk products causes disease Ticks do not transmit the disease to humans BSL 2-3 | Coxiella burnettii |
| Chlamydia Lack of symptoms: 75 % of women and 50% of men with Chlamydia lack symptoms of the infection If symptoms do occur, they appear between 1- 3 weeks after exposure | What is the quiet sexually transmitted disease? Why? |
| Lipid enveloped viruses | Which is more susceptible: lipid enveloped viruses or non lipid viruses? |
| Viruses that infect bacteria | Bacteriophages |
| Small pox and cattle plague Next -> polio | Which viral diseases have been eradicated? |
| Viral characteristics the disease associated with it geographical area they were 1st identified the genetic element they contain or way of replication | What may the names of viruses describe? |
| Enveloped virus | Which kind of virus must stay wet and cannot survive in the GI tract? |
| Yes 20% of cancers are linked to viral infections | Are cancers linked to viral infections? |
| Sporothrix schenckii | What is a BSL 2 fungus? |
| The fungus Coccidioides | Valley fever is caused by? |
| C. immitis | What is the most dangerous fungus on the planet? |
| 1. Microsporum (hair and skin, rarely nail) 2. Trychophyton (hair, skin and nail) 3. Epidermophyton (only1 fungus, invades nail and skin not hair!) | What are the 3 genera of dermatophytes? |
| Blood and serum - blood culture (- mannan/anti-mannan) (- beta-D-glucan) Tissue - direct microscopy and histopathology - culture | Essential tests |
| Aspergillus | Galactomannan is limited to one species, which one? |
| Extremely sensitive to the polysaccharide (1,3)-beta-D-glucan Pan-fungal (Temperamental, many false +ves) Non specific (90% sensitivity, 100% specificity) Expensive | Pros and cons of beta-D-Glucan: |
| The liver is the primary target | Turkey x disease |
| Produced by: Penicillium (P. camemberti) and Aspergillus (A. oryzae) Wheat, oats, rye, corn, barley & rice | Citrinin Yellow rice disease |
| Produced by claviceps (plant pathogens) Such as the hallucinogenic Lycergic Acid Diethylamide | Ergol alkaloids (LSD) |
| Idiopathic pulmonary hemorrhage in infants (first borne curse) sick building syndrome (SBS) due to s.chartarum | Stachybotryotoxicosis |
| Red mould disease Fungus: Fusarium spp. | Akakabi-byo |
| Fungus: Fusarium moniliforme Toxin: fumonisins Clinical presentation: Dysphagia, pain, haemorrhage | Oesophageal cancer |
| Fungi: Aspergillus flavus & A. parasiticus Toxin: Aflatoxins Clinical presentation: Acute and chronic hepatitis, liver failure | Hepatitis and hepatic cancer |
| Fungus: Fusarium spp. Toxin: Fusarium metabolites Clinical presentation: Thrombocytopenia, purpura | Onyalai disease |
| Percolozoa- Naegleria | What is the brain eating amoeba? |