Upgrade to remove ads
Only $2.99/month

Medically Important Bacteria

Terms in this set (29)

Mycobacterium tuberculosis
DISEASE: Tuberculosis
SYMPTOMS: lung consolidation, granulomatous inflammation, cough with blood (haemoptysis)
DIAGNOSIS: acid-fast bacilli (ZN stain), weakly gram+ rod,
VIRULENCE: lipid-rich cell wall, grow inside macrophages,
EPIDEMIOLOGY: 90% latent infections, can be multidrug resistant, 1/3 of world population infected, spreads by aerosol
TREATMENT: isoniazid and rifampicin unless resistant
Staphylococcus aureus
DISEASE: endocarditis, osteomyelitis, toxic shock syndrome, necrotising pneumonia, skin & tissue infections (impetigo, mastitis)
SYMPTOMS: purulent inflammation, often abscess, focus of necrosis
DIAGNOSIS: gram+ cocci in clusters, golden colonies, coagulase+, catalase+
VIRULENCE: haemolysins, Panton-Valentine leukocidin, Protein A (binds Fc), coagulase, superantigenic TSST
EPIDEMIOLOGY: colonises nasal mucosa and skin, survives on dry surfaces for months, can be methicillin/multidrug resistant (MRSA) often hospital acquired
TREATMENT: beta-lactams unless resistant
Streptococcus pyogenes
DISEASE: impetigo, erysielas, cellulitis, necrotising fasciitis, pharyngitis, scarlet fever
SYMPTOMS: inflammation of skin, tonsular exudate (pharyngitis), fever
DIAGNOSIS: beta-haemolytic, gram+ cocci in chains
VIRULENCE: capsule, pyrogenic exotoxin, streptolysin O/S, DNase, hyaluronidase
EPIDEMIOLOGY: normal upper RT/GIT/genital flora, pharyngitis more common in winter
TREATMENT: so far always penicillin sensitive
Streptococcus pneumoniae
DISEASE: Pneumonia, meningitis, infective endocarditis, bacteraemia, otitis media, sinusitis
SYMPTOMS: rapid onset of chills, fever, productive cough (pneumonia)
DIAGNOSIS: alpha-haemolytic, gram+ cocci in pairs,
VIRULENCE: capsule, many serotypes, pneumolysin
EPIDEMIOLOGY: colonises upper RT of ~30% of healthy people, mostly endogenous infection, person-person spread is rare, more common in winter, vaccines exist, may be antibiotic resistant
TREATMENT: beta-lactams if susceptible
Bacillus anthracis
DISEASE: Anthrax, pneumonia
SYMPTOMS: black necrotic lesions
DIAGNOSIS: spore forming gram+ rods
VIRULENCE: lethal toxin, edema toxin, capsule
EPIDEMIOLOGY: found in 'anthrax belt' in NSW, has been used for bio-warfare
TREATMENT: beta-lactams, antibody therapy
Listeria monocytogenes
DISEASE: neonatal sepsis, meningitis, gastroenteritis
SYMPTOMS: fever, muscle aches, diarrhoea
DIAGNOSIS: gram+ rod, weak beta-haemolysis, motile
VIRULENCE: haemolysins, intracellular
EPIDEMIOLOGY: found in soil, mammalian gut, contaminated dairy products (soft cheeses), neonates/elderly at risk
TREATMENT: generally ampicillin, potneitally bacteriophage therapy(!?)
Corynebacterium diphtheriae
DISEASE: Diphtheria
SYMPTOMS: pseudomembrane forms across traches, pharyngitis
DIAGNOSIS: club shaped gram+ non-motile rods
VIRULENCE: diphtheria toxin attacks mucosal epithelium, heart, nerve cells
EPIDEMIOLOGY: mostly occurs in children, vaccination has been very successful for prevention
TREATMENT: metronidazole, erythromycin, penicillin
Francisella tularensis
DISEASE: Tularaemia aka rabbit fever
SYMPTOMS: multiple forms- swollen, potentially suppurative lymph nodes (with epithelioid granulomas), moderate-severe fever, potential skin lesions
DIAGNOSIS: gram- coccobacilli, growth on selective media (glucose-cysteine BA), PCR & gene sequencing
VIRULENCE: intracellular infection of macrophages
EPIDEMIOLOGY: mostly found in N. America and spreads by ticks/deer flies from other mammals to humans, however has been found in Tasmania
TREATMENT: doxycycline and moxifloxacin
Neisseria gonorrhoeae
DISEASE: Gonorrhoea
SYMPTOMS: discharge from the urethra (male) or endocervix (female), can also cause pelvic inflammatory disease
DIAGNOSIS: gram neg diplococci viewed in discharge, PCR
VIRULENCE: capsule, pilli (allow colonisation)
EPIDEMIOLOGY: sexually transmitted
TREATMENT: ceftriaxone
Neisseria meningitidis
DISEASE: Meningococcal disease
SYMPTOMS: fever, headache, neck pain, haemorrhagic rash, can cause pharyngitis, sepsis
DIAGNOSIS: gram neg diplococci (like 2 coffee beans!), blood cultures, CSF stain oxidase +ve
VIRULENCE: capsule, pilli
EPIDEMIOLOGY: most common in children under 5, then teenagers, commensally carried in the nasopharynx of 10% of people, can be vaccinated for
TREATMENT: cephalosporin, rifampin as prophylactic
Escherichia coli
DISEASE: various food poisoinings, haemorrhagic colitis, haemolytic uremic syndrome, UTI, bacteraemia
SYMPTOMS: diarrhoea, character depends on serotype
DIAGNOSIS: gram -ve rod, lactose fermenter, serology for serotype
VIRULENCE: O antigen (outer membrane), H antigen (flagella), K antigen (capsule), multiple serotypes some of which cause more severe disease, e.g.
ETEC enterotoxigenic - watery diarrhoea
EPEC enteropathogenic - prolonged watery diarrhoea
EIEC enteroinvasive - bloody diarrhoea
EHEC enterohaemorrhagic - bloody diarrhoea, haemorrhagic colitis can progress to HUS
EPIDEMIOLOGY: mostly normal flora of the GIT, more severe cases can be foodborne (fecal-oral route),can be multi-resistant esp. in hospital
TREATMENT: ampicillin unless resistant
Klebsiella pneumoniae
DISEASE: UTI, lobar pneumonia, liver abscess
SYMPTOMS: thick, bloody, mucoid sputum (currant jelly sputum)
DIAGNOSIS: gram -ve rod, lactose fermenter, catalase +ve, non-motile, facultative anaerobic
VIRULENCE: large polysaccharide capsule, complement resistant
EPIDEMIOLOGY: usually normal gut flora, commonly antibiotic resistant (esp. ampicillin), K1 strains endemic in SE Asia (liver pathogenic), usually only infect the immunocompromised/those with COPD. UTI responsible in the elderly
TREATMENT: cephalosporine unless resistant
Salmonella typhi
DISEASE: Typhoid fever
SYMPTOMS: fever, bradycardia, bleeding from nose, Peyer's patches, rose spots on trunk
DIAGNOSIS: essentially a serotype of E. coli, gram -ve rod, non lactose fermenter, Widal test serology for serotype on stool
VIRULENCE: O antigen (outer membrane), H antigen (flagella), mutliple related serovars. Persists in chronic reservoirs in the gallbladder
EPIDEMIOLOGY: faeco-oral transmission, will not die due to refrigeration, can be carried asymptomatically, can be drug resistant, can be waterborne or zoonotic
TREATMENT: antipyretics + ceftriaxone
Shigella sp.
DISEASE: Dysentery
SYMPTOMS: frequent low volume stools with cramps, blood, mucus pus, necrosis of the colonic epithelium
DIAGNOSIS: gram -ve rod, non-lactose fermenting, stool microscopy
VIRULENCE: Shiga toxin (damages intestinal & glomerular endothelium), endotoxin, egnes for adherence and invasion
EPIDEMIOLOGY: humans are the only reservoir, infectious dose is very low (~100 cells), faeco-oral route, sometimes outbreaks in children & MSM
TREATMENT: electrolyte rehydration + quinolones
Bordetella pertussis
DISEASE: Whooping cough
SYMPTOMS: inspiratory whooping, inactivation of cilia leads to coughing
DIAGNOSIS: gram -ve coccobacilli, small & paler than E. coli, PCR of nasopharyngeal aspirate
VIRULENCE: exotoxin, filamentous haemagglutinin, adenylate cyclase toxin, dermonecrotic toxin
EPIDEMIOLOGY: vaccination is highly effective, 4 day to 2 week incubation, humans only
TREATMENT: azithromycin, clarithromycin, or erythromycin unless allergic
Legionella pneumophila
DISEASE: Legionnaires disease
SYMPTOMS: multifocal pneumonia, often headache & diarrhoea
DIAGNOSIS: gram -ve rod, no capsule, fastidious,
VIRULENCE: intracellular pathogen of alveolar macrophages,
EPIDEMIOLOGY: grows best in warm water sources e.g. hot tubs, AC, cooling towers, high mortality (5-30%) no human-human transmission
TREATMENT: fluoroquinolones or macrolides
Treponema pallidum
DISEASE: Syphilis, Bejel, Yaws, pinta
SYMPTOMS: painless chancre, perivascular tissue destruction, flu-like symptoms, can form granulomas, can progress to neural tissue
DIAGNOSIS: poorly staining spirochete, motile by periplasmic flagella, Dieterle stain, serology
VIRULENCE: intracellular pathogen, hyaluronidase, antiphagocytic, bacteria can persist for decades despite vigorous immune response
EPIDEMIOLOGY: syphilis is sexually transmitted, others by contact from chancres, easily treatable by penicillin
TREATMENT: intramuscular benzathine benzylpenicillin as a single dose
Leptospira interrogans
DISEASE: Fever, Weil's syndrome
SYMPTOMS: jaundice/hepatitis, renal failure, myocarditis, meningitis
DIAGNOSIS: thin coiled spirochaetes with hooked ends, silver stain, dark field examination of blood, obligate aerobe, fastidious, can be isolated from urine
VIRULENCE: can survive in water for months
EPIDEMIOLOGY: invade via broken skin, zoonotic from wild rodents urine, risk factors = farming, sewer work. Multiple serovars from different animals
TREATMENT: doxycycline, ampicillin if severe
Mycoplasma pneumoniae
DISEASE: atypical pneumonia
SYMPTOMS: flu-like
DIAGNOSIS: no rigid cell wall, fastidious, CXR often more dramatic than symptoms, complement fixation
VIRULENCE: attachment organelle
EPIDEMIOLOGY: droplet transmission peaks in winter, often infection is persistent even with therapy
TREATMENT: macrolides
Chlamydia trachomatis
DISEASE: epidiymitis, conjunctivitis, trachoma
SYMPTOMS: vary by serovar, can cause chronic conjunictivitis, corneal scarring, neonatal pneumonia, pelvic inflammatory disease, infertility
DIAGNOSIS: gram -ve, obligate intracellular, outside cell form 300nm elementary bodies, inside cell form 800nm inclusion body, ELISA
VIRULENCE: inhibit lysozome fusion, 15 serovars,
EPIDEMIOLOGY: trachoma can spread via flies, mostly STI
TREATMENT: doxycycline
Coxiella burnetii
DISEASE: Q fever
SYMPTOMS: sudden onset fever, pneumonia, hepatomegaly, potentially behavioural disturbance, auto-antibodies to mitochondria, can be chronic and progress to endocarditis
DIAGNOSIS: short pleomorphic rod, fastidious, complement fixation (2 phases of antigens)
VIRULENCE: spore forming, grows in phagosomes
EPIDEMIOLOGY: transmitted by aerosol or infected milk, zoonotic (cows, sheep, pregnant cats), closely related to Rickettsia
TREATMENT: doxycycline
Rickettsia prowazekii
DISEASE: Typhus
SYMPTOMS: fever, headache, rash, back pain, photophobia
DIAGNOSIS: gram -ve coccobacilli, fastidious, obligate intracellular, can only be cultured in organisms, immunofluorescence, serology
VIRULENCE: very small (1 Mb) genome, protein microcapsular layer and slime layer
EPIDEMIOLOGY: vector is the body louse and other mammal hosts (e.g. flying squirrel), 20-50% untreated mortality 'sometimes been regarded as a model for the bacterial ancestor of mitochondria'
TREATMENT: doxycycline
Yersinia pestis
DISEASE: Bubonic plague
SYMPTOMS: fever, painful buboes, inguinal lymphadenopathy
DIAGNOSIS: gram negative coccobacilli, culture fluid from buboes, CIN agar is selective, non-haemolytic, citrate/indole/urease -ve
VIRULENCE: somatic antigens V&W and capsular antigen F1 resist phagocytosis, LPS endoteoxin, coagulase, fibrinolysin
EPIDEMIOLOGY: carried by fleas (on rats), 60% mortality if untreated (~10% if treated)
TREATMENT: streptomycin, gentamicin, doxycycline
Chlamydophila psittaci
DISEASE: Psittacosis
SYMPTOMS: fever, chills, malaise, dyspnoea, mild pharyngitis
DIAGNOSIS: gram -ve, obligate intracellular, serology (may cross react w. other chlamydia)
VIRULENCE: inhibit lysozome fusion, exist as elementary bodies
EPIDEMIOLOGY: infects birds, occupation disease of zookeepers, petshop workers, poultry farmers. Human-human is rare. Aerosolised avian excreta is inhaled
TREATMENT: tetracycline or macrolides
Clostridium botulinum
DISEASE: Botulism
SYMPTOMS: facial muscle weakness, problems with vision and swallowing,
DIAGNOSIS: gram+ spindle shaped, spore forming anaerobes
VIRULENCE: mostly botulism toxin, other haemolytic enzymes
EPIDEMIOLOGY: can be found in canned foods, IV drug use
TREATMENT: botulism antitoxin, antibiotics
Clostridium difficile
DISEASE: pseudomembranous colitis, CDAD, toxic megacolon
SYMPTOMS: bloating and diarrhea with abdominal pain, foul stool odour
DIAGNOSIS: toxin tests and PCR, motile, spindle shaped gram+
VIRULENCE: exotoxin A (neutrophil chemoattractant), exotoxin B (depolymerises actin) , spore forming
EPIDEMIOLOGY: increasingly nosocomial infection, may exist as normal flora but cause disease when other flora is depleted by broad spectrum antibiotics
TREATMENT: metronidazole, faecal transplant!
Clostridium tetani
DISEASE: Tetanus
SYMPTOMS: spastic paralysis, muscle rigidity and spasms near wound, ROAST symptoms
DIAGNOSIS: gram+ spindle shaped, obligate anaerobe
VIRULENCE: tetanospasmin toxin (prevents release of inhibitory neurotransmitters, is a protease that cleaves synaptobrevin), tetanolysin, spore forming
EPIDEMIOLOGY: can be vaccinated against, spores enter open wounds
TREATMENT:
Clostridium perfringens
DISEASE: gas gangrene, food poisoning
SYMPTOMS: tissue necrosis
DIAGNOSIS: anaerobic, gram+ spindle shaped, Nagler's reaction on egg yolk plate w. anti-toxin (lecithinase)
VIRULENCE: spore forming, alpha toxin (lecithiniasecreates gas),
EPIDEMIOLOGY: food poisoning appears common due to anti-toxin antibodies widespread among population
TREATMENT: amputation of necrotic tissue, penicillin
Yersinia enterocolitica
DISEASE: Yersiniosis
SYMPTOMS: febrile, bloody diarrhoea
DIAGNOSIS: gram-negative coccobacillus
VIRULENCE: Trimeric Autotransporter Adhesins (TAA), 57 serogroups, siderophilic, enterotoxin
EPIDEMIOLOGY: zoonotic (cattle, deer, pigs, birds), most common contaminant of stored blood, common in patients with haemochromatosis
TREATMENT: GI infection often resolves without antibiotics, severe infections use doxycycline
THIS SET IS OFTEN IN FOLDERS WITH...