Case Studies Flashcards
What organisms are currently vaccinated against in Ireland?
N. meningitidis (MenC and MenB)
H. influenzae type B (Hib vaccine)
Bordetella pertussis (pertussis vaccine against whooping cough)
S. pneumonia pneumococcal vaccines: PCV7, PCV13, PPV23
What organisms cause food poisoning?
Staphylococcus aureus
Shigella
Salmonella
Yersinia enterocolitica
Clostridioides perfringens
Bacillus Cereus
Zoonotic infections:
(2)
Pasteurella Multocida
Salmonella (lizards)
Yersinia pestis (animals, rats, pets etc)
B. anthracis
Health Care Associated Infections
ESKAPE
- Enterococcus faecium (Vancomycin resistance)
- S. aureus (Methycillin resistance)
- Klebsiella Pneumonia (CBE)
- Acinetobacter baumanii (MDR)
- Psudomonas auriginosa (MDR)
- Enterobacter species (E.COLI) (ESBL)
Citrobacter freundii also is
S. aureus infections
Superficial skin infections:
- Folliculitis
- Furuncles
- Carbuncles
Skin infections
- Impetigo
- Cellulitis
- Mastitis
Systemic infection
- Bloodstream infections
- Endocarditis
- Pneumonia
- Osteomyelitits
- pyelonephritis
Toxin infections
- Toxic shock syndrome
- Scaled skin syndrome
- Gastroenteritis
S. aureus food poisoning
Foods:
- ready to eat foods
- salads: ham, egg, tuna, chicken, potato
- bakery products e.g. cream filled
- sandwiches
- mild and dairy products
Enterotoxin
Onset:
- 2-6 hours after ingestion
- resolved in 8 to 24 hours
Symptoms
- severe nausea, vomiting, abdominal pain and diarrhoea triggered by toxin
S. epidermidis infections:
Device associated infection and HCAI BSI
S. saprophyticus infections
UTI in sexually active women
Opportunistic HCAI
Opportunistic infection in immunocompromised
Micrococcus infection:
Opportunistic e.g. UTI
N. gonorrhoeae infections:
STI
- prostatitis
- epididymitis
- gonoccaemia
- joint disease
- Pelvic Inflammatory disease
- Infertility
- ectopic pregnancy
- transmitted to infants - conjunctivitis
N. meningitidis infections:
BSI
Meningitis
Meningococcaemia
Invasive meningicoccal disease (acute meningitis or meningococcemia)
M. catarrhalis infection
Otitis medium
Sinusitis
Pneumonia
Bronchitis
H. influenzae type B infection
Meningitis
Epiglotis
BSI
Cellulitis
Arthritis
Osteomyelitis
H. influenzae non typable infections:
Otitis
Sinusitis
Pneumoniae
H. aegyptius infection
Conjunctivitis
H. parainfluenzae infection
Pneumoniae
Endocarditis
H. ducreyi infection
Chanchroid (lymph nodes and genital)
Pasteurella Multocida infection:
Zoonotic: dog bites and cat scratches
Swelling
Cellulitis
Chronic pulmonary disease in compromised
Systemic infection in compromised
Bordetella pertussis infection:
Whooping cough
Pneumoniae and encephalitis in convalescents
S. pneumonia infections:
Acute bacterial pneumoniae
Otitis media
Invasive pneumococcal disease:
- Blood stream infection
- Meningitis
- sterile site infection
S. viridans infections:
BSI through minor trauma to gums
Sub acute bacterial endocarditis in those with damaged heart valves
Strep mutans infections:
Plaque formation
Tooth decay
S. pyogenes infections:
Pharyngitis
Scarlet fever
Skin infections
Impetigo
Cellutis
Erysipelsia
Necrotising facitis
Streptococcal Toxic Shock Syndrome
Rheumatic fever
Glomerular nephritis
S. agalactiae infection:
Group B strep
Prenatal onset GBS
Early-onset GBS
Late-onset GBS
Most common cause of life threatening infection in newborn babies
Enterococci infections
UTI
Intra abdominal abscess
Endocarditis
BSI
Shigella infection:
Food poisoning
Shigella (sonnei) food poisoning
Cause:
- Shiga toxin
Food:
- Chicken, tuna and potato salad
Transmission:
- faecal to oral route
- food, faeces, fingers, flies, fomites
- very low infective dose (<200 cells)
Incubation
- 24 to 50 hours
Symptoms
- diarrhoeae (bloody)
- abdominal pain
- fever
- possible invasive infection
Salmonella infections:
Food poisoning
Septicaemia (cholera suis)
Gastroenteritis (typhimurium and enteriditis)
Parathyphoid fever (parathyphi) -> enteric fever
Thyphoid fever (thyphi) -> leads to enteric fever
Yersinia infections:
Bubonic plague (Y. pestis) -> flea bites or contaminated animal tissue
Food poisoning (Y. enterocolitica)
Yersinia Enterocolitica food poisoning:
Sources:
- PORK, milk, poultry, shelfish, vegetables, cold foods (4 degrees +)
Incubation:
- 24 to 36 hours
Symptoms:
- Diarrhoeae (bloody in 25% of children)
- fever
- headache
- abdominal pain
- appendicitis like in children (pseudoappendicitis)
- BSI in elderly
Pathology
- invasion of iluem
- necrosis of peyers patches
- inflammation of mesenteric lymph nodes
Proteus infection
UTI - second most common cause after EPEC
Klebsiella infections:
Commensal but frequently an opportunistic pathogen causing BSI, HCAI UTI, VAP pneumoniae
Enterobacter infections:
Opportunistic Infections
Health Care Acquired Infection
Antimicrobial Treatment
Catheters
Invasive Procedures
Burns/ wounds
Pneumonia
UT
Citrobacter infections:
Inhabitant of soil and water and found in GIT
Citrobacter freundii- main pathogen
Healthcare-associated infection, UTI, bacteraemia
E. Coli infection
Neonatal meningitis -> ExPEC
Watery diarrheae -> ETEC enterotoxigenic
Watery diarrhea of long duration -> EPEC enteropathogenic
Bloody diarrhea -> EHEC enterohaemorrhagic
Bloody diarrhea -> EIEC enteroinvasive
Persistant watery diarrhear in children and HIV -> EAEC enteroadherant
EHEC infection
Enterohaemorrhagic E. Coli
Blood diarrhea
Haemorrhagic colitis
Haemolytic uremic syndrome (HUS)
EnteroInvasive E. Coli infection:
Inflammatory dysentry
Bloody diarrhoea
Large intestine
Intracellular pathogen
Fever
Enterotoxigenic E. Coli Infection:
Non inflammatory diarrhoea in children in developing countries
Travellers diarrhoea
E. Coli 0157:H7 (EHEC/STEC/VTEC) infections
Intestinal
- asymptomatic
- watery diarrhoea
- haemorrhagic colitis
Systemic
- haemlytic uremic syndrom HUS
Causes:
- Thrombotic thrombocytopenic purpura (TTP)
- kidney failure
- haemolytic anaemia
Psuedomonas infections:
Pneumonia
Cystic fibrosis associated chest infection
Otitis media
Otitis externa
Bacterial keratitis in eye
Osteomyelitis in bones and joints
Diarrhoea
Enteritis
Enterocolitis
BSI
Endocarditis
Bacillus infections:
B. cereus: food poisoning
B. thuringenesis: insecticide
B. anthracis: zoonotic
B. cereus food poisoning
Foods:
- RICE, dairy products, spices, dried foods, vegetables
- Dried infant formula
Spores:
- heat resistant - food processes
- not removed by regular cleaning
- food industry equipment - dairy pipelines
Emetic or diarrhoeal - both self limiting
Diarrhoeal
- proteinaceous foods (meat, fish, milk, stews, sauces, veg)
- watery diarrhoea
- cramps
- Diarrhoeagenic necrotising enterotoxin
- 6+ hour incubation
- 12 to 24 hours duration
Emetic syndrome
- starchy foods (rice, potato, pasta, noodles, pastry products)
- vomiting
- emetic toxin - cerulide
- 0.5 hours to 6 hours incubation
B. cereus
B. anthrax
2-5 hour incubation
Clostridides perfringens food poisoning
Improperly-handled food is contraminated with spores, which survive cooking temperature
Spores germinate with heating (anaerobiasis) and if > 10^5/g bacteria are ingested, illness may occur
Sporulation in the small intestine releases enterotoxin CPE
Diarrhoea occurs 6-18 hours later, and resolves in 1-2 days
