Micro 2nd SCT 1st semester

Impetigo, furunculus, pneumonia, osteomyelitis, food poisoning etc.

toxic shock syndrome (TSS), scalded skin syndrome, food poisoning

TSST (toxic shock syndrome toxin), enterotoxin, exfoliatin, leukocidins, hemolysins

S. aureus

coagulase

by phage typing

glycopeptides (vancomycin, teicoplanin)

cystitis in young women

• group specific: C- polysaccharide
• type specific: M protein

Streptokinase (fibrinolysin), hyaluronidase, streptodornase (DNAse)

impetigo (pyoderma), cellulitis, erysipelas, fasciitis, myositis

Scarlet fever - erythrogenic toxin – superantigen causing capillary destruction

Glomerulonephritis, rheumatic fever, erythema nodosum, chorea minor.

M protein: may induce hypersensitivity reactions

Life-long immunity. Antitoxic antibodies are involved.

Penicillin-G

type II hypersensitivity (cytotoxic antibodies)

type III hypersensitivity (immune complexes)

Group B Streptococcus (S. agalactiae)

Viridans streptococci

D group polysaccharide antigen; tolerance to bile and hydrolysis of esculin (BEAmedium: bile esculin agar); growth in the presence of 6,5 % NaCl

Gram positive diplococcus, lancet shape, capsule.

Pneumonia, meningitis, sinusitis, otitis media, sepsis, (ulcus serpens corneae)

Demonstration of bacteria (intracellular in PMNs) from urethral discharge by Gramor methylene blue stain; PCR amplification of bacterial DNA

Partial immunity of short duration; no protection from reinfection

arthritis, skin eruptions, (endocarditis, meningitis)

Blenorrhoea (ophtalmia) neonatorum, silver acetate eye drops or erythromycinointment

pilus, outer membrane proteins, LOS (lipooligosaccharide), IgA protease

polysaccharide capsule, LPS, IgA protease

The site of entry is the nasopharynx (transmitted by airborne droplets).Meningococcemia (characterized by skin lesions), and acute (purulent) bacterial meningitis.

• Chemoprophylaxis: rifampin or ciprofloxacin.
• Vaccination: capsular polysaccharide (types A, C, Y and W135). No vaccine against type B!

• Gram or methylene blue stain of CSF sediment.
• Demonstration of bacterial capsular antigens by latex agglutination (from CSF).

type b

Skin, lungs, gastrointestinal tract

Staphylococcus aureus, Enterococcus faecalis, Pseudomonas aeruginosa, Escherichiacoli

• Enteropathogenic E. coli (EPEC)
• Enterotoxic E. coli (ETEC)
• Enteroinvasive E. coli (EIEC)
• Enterohemorrhagic E. coli (EHEC)
• Enteroaggregative E. coli (EAggEC)

urinary tract infections, neonatal meningitis, nosocomial wound infections

Escherichia coli

hemorrhagic colitis +/- HUS (hemolytic uraemic syndrome)

humans (with disease, or healthy carriers)

• Salmonella typhi (typhoid)
• Salmonella paratyphi A, B, C (enteric fever)

Blood, (bone marrow)

Ingestion of contaminated food (such as eggs, cream, mayonnaise, creamed foods, etc.)containing a sufficient number of Salmonella.

Antibiotics are not usually necessary unless the infection is generalised. In case of extraintestinal infection (very young, very old or immunosuppressed patients):ampicillin, gentamicin, trimethoprim/sulfamethoxazole, or ciprofloxacin.

Shigella dysenteriae, S. flexneri, S. boydii, S. sonnei

Shigella dysenteriae, (Shigella flexneri, Shigella boydii, Shigella sonnei), enteroinvasive E. coli (EIEC)

Campylobacter jejuni, Escherichia coli, Salmonella enteritidis, Shigella, Yersinia enterocolitica

Salmonella (not Typhi and Paratyphi!), Campylobacter jejuni, Yersinia enterocolitica, Listeria monocytogenes, E. coli O157

• - Bubonic plague is transmitted by the bite of infected rat fleas from rats to humans.
• - Primary pneumonic plague spreads directly from human to human via respiratory droplets.

tick bite, mucous membranes, skin abrasions, resp. tract, gastroint. tract

Via contaminated milk products or through skin abrasions (contact with animals).Organisms spread to the mononuclear phagocytes of the reticuloendothelial system(lymph nodes, liver, spleen, bone marrow).

• B. abortus: cattle
• B. melitensis: goat, sheep
• B. suis: swine

Cholera toxin activates the adenylate cyclase enzyme in cells of the intestinal mucosa leading to increased levels of intracellular cAMP, and the secretion of large amount of water, Na+, K+, Cl-, and HCO3- into the lumen of the small intestine.

Rapid intravenous or oral replacement of the lost fluid and ions. (Administration of isotonic maintenance solution should continue until the diarrhea ceases.) In severe cases:administration of tetracycline (in addition to rehydration).

• purulent meningitis
• epiglottitis (obstructive laryngitis)
• otitis media and sinusitis
• pneumonia
• (cellulitis, arthritis)

Chancroid (soft chancre or ulcus molle)

Pseudomonas species are normally present in the environment and can be isolated from the skin, throat, and stool of some healthy persons. They often colonize hospital food,sinks, taps, mops, and respiratory equipment.

• urinary tract infections
• wound infections (burns)
• pneumonia, sepsis (immunosupression)
• otitis externa

certain penicillins: piperacillin/tazobactam combination

a 3rd generation cephalosporin: ceftazidim

a 4th generation cephalosporin: cefepime

certain aminoglycosides: gentamycin, tobramycin, amikacin

carbapenems: imipenem, meropenem

• - legionellosis, legionnairs’ disease (atypical pneumonia)
• - Pontiac fever (mild, flu like illness without pneumonia)

• filamentous hemagglutinin, pertussis toxin,
• adenylate-cyclase toxin, trachealcytotoxin

Staphylococcus aureus, Bacillus cereus, Clostridium perfringens, Clostridiumbotulinum, Vibrio parahaemolyticus, (Salmonella serotypes causing enterocolitis)

Bacteroides fragilis

Clostridium, Bacteroides, Prevotella, Porphyromonas, Fusobacterium, Actinomyces,Bifidobacterium, Peptostreptococcus, Propionibacterium

• Clostridium perfringens
• alpha-toxin (lecithinase)

• Clostridium perfringens, C. novyi, C. septicum, C. histolyticum, C. tertium, C.bifermentans, C. sporogenes
• The site of infection is usually a wound that comes into contact with Clostridium spores that germinate in an anaerobic environment.

Wound should be cleaned and debrided; tetanus toxoid booster injection given;tetanus immunoglobulin (TETIG) in previously unvaccinated patients and in case of heavy contamination of wound; penicillin may be added prophylactically

Spastic paralysis: muscle spasms; lockjaw(trismus), rhisus sardonicus (grimace of theface), opisthotonus (spasm of the back); respiratory paralysis

Blocks release of acetylcholine in peripheral nerve synapses;

flaccid paralysis: diplopia (double vision), dysphagia (difficulty to swallow),dysphonia (hoarseness), respiratory paralysis

Treatment: respiratory support + trivalent antitoxin

Not, because antibiotics are not effective against preformed toxins.

Gastritis, peptic and duodenal ulcers, gastric carcinoma, MALT lymphoma

Diphtheria toxin

Inhibits protein synthesis. Inhibits peptide elongation in eukaryotic ribosomes by ADP ribosylation of EF-2 (elongation factor-2)

Antitoxic antibodies, long lasting immunity

Smears of the throat swab should be stained with methylene blue or Neisser stain;bacteria are cultured on Löffler’s or tellurite (Clauberg) medium; toxin production must be demonstrated by agar precipitation ( ELEK-test)

The cell envelope contains a high amount (60 – 70 %) of complex lipids: mycolic acid,cord factor. Once the cells are stained (by carbol-fuchsin) they resist decolorisation by acid-ethanol.

M. kansasii, M. marinum, M. avium-intracellulare complex, M. fortuitum-chelonei complex

• Acid-fast staining (Ziehl-Neelsen)
• Culture on selective media (Löwenstein-Jensen agar, liquid BACTEC medium)
• PCR amplification of bacterial DNA

To prevent the overgrowth of drug-resistant mutants during the long treatment period (if bacteria resistant to one drug emerge, they are most probably inhibited by the other drugs).

activated macrophages

isoniazid (INH), pyrazinamid, rifampin, (ethambutol, streptomycin)

It causes TB, especially in immunosuppressed patients (such as AIDS patients).

human

environment (soil, water)

Tuberculoid, lepromatous forms

Brucella, Francisella tularensis, Yersinia pestis, Pasteurella

Listeria monocytogenes, Bacillus anthracis, Erysipelothrix rhusiopathiae

E. coli, Klebsiella, Proteus, Pseudomonas aeruginosa, Enterococcus faecalis

• aerobic: Staphylococcus epidermidis
• anaerobic: Propionobacterium acnes

Gram positive aerobic: Staphylococcus, Streptococcus, Bacillus, Corynebacterium,…Gram positive anaerobic: Clostridium, Actinomyces, Propionibacterium, Lactobacillus

• Gram negativ aerobic: Vibrio, Neisseria, Haemophilus…
• Gram negativ anaerobic: Bacteroides, Prevotella, Porphyromonas, Veillonella…

• Gram positive coccus: Staphylococcus, Streptococcus
• Gram negative coccus: Neisseria, Veillonella
• Gram positive rod: Clostridium, Bacillus

• Gram negative rod: E. coli, Salmonella, Shigella
• Spirochetes: Treponema, Borrelia, Leptospira

Gram positive (dark blue) rod (it usually does not form spores in vivo)

Metronidazol, amoxicillin + clavulanic acid, imipenem

Streptococcus agalactiae, E. coli, Listeria monocytogenes

Neisseria meningitidis, Haemophilus influenzae, Streptococcus pneumoniae

Brucellae

Acute disease, usually with vomiting and diarrhea, caused by preformed toxins produced by bacteria contaminating the food. The period between consumption of food and the appearance of symptoms is short (< 4-6 hours).