Bacterial Infections & Antibiotics Flashcards
Toxin mediated diseases?
Toxic shock syndrome
Kawasaki Disease
Eczema exac/psoriasis
Pathogenesis of super antigens causing disease?
MHC II binds with T cell resulting in polyclonal activation (contrast to regular antigens presenting to a specific T cell receptor)
Therefore super antigen is not MHC restricted resulting in overwhelming cytokine release
Eagle effect and abs to use to avoid this?
When bacteria in stationary phase of replication penicillin is less effective
Clindamycin used instead
Criteria for staph TSS and management?
Fever >38.9C Hypotension <90sys Rash - diffuse, macular erythematous Desquamation of palms/soles 1-2/52 later Multisystem involvement - GI, muscular, mucus membranes, kidney, liver, ham or CNS ---> treat with fluclox and clindamycin
Criteria for strep TSS and RFs?
GAS found in normally sterile site (blood, urine)
Hypotension
Kidney, coagulopathy, liver, ARDS, soft tissue necrosis
RFs - trauma, NSAIDs, surgery, viral infection, post-partum
Gram positive cocci, coagulase positive?
Staph aureus
Gram positive cocci, coagulase negative?
Staph epi, Staph hemolyticus
RF for coat neg staph?
Indwelling lines/implants
CONS forms a biofilm, enhances adhesion and resist phagocytosis
Treatment for CONS?
Vancomycin - most are resistant to fluclox
& remove devices
MecA positive organism?
MRSA
Superantigen or not: Staph food poisoning? Staph scarlet fever? Staph scalded skin? TSS?
Food poisoning - toxin but not super antigen
Scarlet fever - toxin but not super antigen
Scalded skin - toxin but not super antigen
TSS - super antigen
Gram pos cocci, catalase negative?
Streptococci
Group A strep?
Strep pyogenes
Group B strep?
Strep agalactiae
Group C/D strep?
Beta haemolytic strep
Group D strep?
Enterococcus
Group E&F strep?
Alpha haemolytic (pneumoniae/viridians)
Group A Strep acute infections?
Strep throat Skin infections inc erysipelas Nec fasc Scarlet fever TSS
GAS immune mediated illnesses?
Rheumatic fever
Post-strep GN
Post-strep arthritis
PANDAS
Transmission rate of GBS?
50%
Invasion rate 1-2%
10-30% of women GBS +
Abx in labour reduces neonatal sepsis?
Reduced EOS by 65%
NO CHANGE in LOS
RFs for GBS in labour?
Prev infant w EOS GBS GBS bacteria SPTL <37/40 ROM >18hrs Intrapartum fever >38C
- if any present treat with abx
What else to look for in strep intermedium bacteraemia?
Abscesses
RF for enterococcus infection?
Damaged mucosa, impaired immune response
Gram positive bacteria, lancet shaped diplococcus.
Strep pneumoniae
Risk groups for strep pneumoniae infection?
Sickle cell
Asplenia
Acute nephrotic syndrome
Deficiency in humeral immunity
- polysaccharide capsule prevents phagoytosis
Conjugate vs polysaccharide vaccine pneumococcal vaccine?
Conjugate - T cell immunity, reduces nasopharyngeal carriage (routine on imms schedule)
Polysaccharide - limited response in children <2 and immune compromised (additional for high risk)
Gram positive rods?
Bacillus cereus - gastro
Clostridium difficile, tetani, and botulinum
Listeria
Toxin associated with clostridium ?
Tatanospasmin
—> prevents release of glycine and GABA which blocks normal inhibition of antagonistic muscles causing contractions
Management of tetanus?
Tetanus IVIG and tetanus vaccine
Immunoglobulin neutralises toxin - needs to be given early
Exposure to toxin does not infer immunity - vaccination!
RFs for C Diff?
Abx - cephalosporins, Olinda and fluoroquinolone
Healthcare setting
PPIs
Chemotherapy
Gram pos bacilli?
Corynebacterium diptheria
Only gram pos bacteria to have an endotoxin?
Listeria
Mortality rate of listeria in utero?
50% in prev infants
30% EOS
15% LOS
Gram negative cocco bacillus?
Haemophilus Influenza B
% of HiB producing beta-lactamase?
1/3
Resistant to amp/amoxy so treat with augmentin
Gram neg diplococcus?
Moraxella catarrhalis
Treatment moraxella?
Augmentin
Gram neg pleomorphic bacillus?
Bordetella pertussis
Gram negative diplococcus?
Neisseria meningidites
Peaks of neisseria disease?
Bimodal -> <2 and teenagers
RFs for neisseria meningitis?
Complement deficiency Eculizumab treatment Asplenia HIV HSCT
Seizures/focal neurology more common with meningitis from which organisms?
HiB and Strep meningitis
Gram negative rods?
Non-typhoid salmonella
Campylobacter
Associations salmonella w underlying illness
Reactive arthritis (HLA B27)
OM (sickle cell)
Multi-organ failure (HIV)
Toxic megacolon (IBD)
Mx non-typhoid salmonella?
Not recommended for uncomplicated salmonella - suppresses normal flora
Neonates <3mths
If febrile or toxic, bacteraemic or with vascular grafts or haemoglobinopathies
Immunocompromised
Dysentery with HUS/SIADH?
Shigella
Shiga toxin mediated
RFs for cholera?
Blood group O
Decreased gastric motility
Malnutrition
Immunocompromise
Painless profuse diarrhoea with metabolic acidosis, hypokalaemia and hypoglycaemia. Stool shows chloride ++ bt no leukocytes
Cholera
Gastro with blood 2-4 days after onset. Lasts 1-2 weeks. Pathogen?
Campylobacter
Complications of campylobacter?
Reactive arthritis
Erythema nodosum
IBS
GBS
Enterocolitis/mesenteric adenitis in child with thalassemia?
Yersinia
Complications of Yersinia?
Assoc w KD - superantigen
Eryhtema nodosum, arthritis, uveitis
Gram neg bacilli?
E Coli
Gram neg aerobe?
Pseudamonas
Klebsiella
Bartonella
Ectheyma gangrenous?
Pseudamonas
Lymphadenitis with red papules at site of scratch. Rarely may have hepatomegaly, conjunctivitis. Pathogen?
Bartonella
OM/SA in child with minimal inflammation marker rise, no improvement on fluclox?
Kingella
Traveller from NT in wet season, presents with skin lesion and pulmonary infection?
Meliodosis
Pseudomallei
