Infections On Surfaces Flashcards
What is a surface?
Interface between a solid and either a liquid
or gas.
Name some skin micro organisms
Viruses
– Papilloma (can be carcinogenic)
– Herpes simplex
Bacteria
Gram positive
– Staph aureus
– Coagulase negative staphylococci - All staphylococci except staph aureus
– Corynebacterium - Never cause significant disease outside a healthcare setting
Gram negative
– Enterobacteriaceae
Fungi
– Yeasts - All have small numbers of candida species,
– Dermatophytes - Multicellular fungi, live on skin, some infect hair and nails, cause athletes foot,
Parasites
– mites
Name mucosal flora of the eye
Coagulase negative staphylococci, diphtheroids, saprophytic Neisseria species, viridans group streptococci
Name mucosal flora of the nares
Staph aureus
Name mucosal flora of the nasopharyngeal
Neisseria meningitidis (a lot of people have this but not have disease), Streptococcus pneumoniae, Haemophilus influenzae,
Name mucosal flora of the mouth
Viridans Streptococci (can get to heart), Neisseria, Veillonella, Lactobacillus, Actinomyces, Bacteroides, Capnocytophaga, Eikenella, Prevotella, fusobacteria, clostridia, propionibacteria, Candida, Geotrichum species
NAME MUCOSAL FLORA OF THE STOMACH
Helicobacter - can cause peptic ulceration - treated with a week/2 of antibiotics - they are a precursor for gastric cancer or lymphoma , streptococci, staphylococci, lactobacilli,
Name mucosal flora of the intestine
Bacteroides, Bifidobacterium, Eubacterium, Lactobacillus, coliforms,
aerobic and anaerobic streptococci, Clostridium, yeasts
Anaerobes in the large bowel
NAME mucosal flora of the urethra
Enterobacteriaceae - gram negs, lactobacilli, diphtheroids, alpha and non-haemolytic streptococci, enterococci,
Can causeuti
Name mucosal flora o the vagina
Lactobacilli - most are these. These produce lactic acid to reduce candida (which cause thrush), diphtheroids, micrococci, coagulase-negative staphylococci, Enterococcus faecalis, microaerophilic and anaerobic streptococci, mycoplasmas, ureaplasmas, yeasts
Describe the distribution of bacteria in the human body
See slide for diagram
What is the most common way of infection
From own microbiota - when you acquire a new strain of myth ur not immune to
• Microbiota = “commensals”
– micro-organisms carried on skin and mucosal surfaces
– normally harmless or even beneficial
– transfer to other sites can be harmful
Name methods of transfer
– Invasion • e.g. Strep pyogenes pharyngitis – Migration • e.g. Escherichia coli urinary tract infection – Innoculation • e.g. Coagulase negative staphylococcus prosthetic joint infection eg after surgery – Haematogenous • e.g. viridans Strep endocarditis -
How can viridans strep cause endocarditis
Viridans need to be anchored down in the mouth, some people e have congenital abnormalities of valves eg bicuspid aorti valve - significant risk of endocarditis - turbulent blood flow over the valves - that erodes the epithelial surface, any bacteria that get from mouth into blood stream (usually taken up by macrophages or in spleen), but bacteria can attach to fibronectin - grow in the heart, body causes inflammatory processes, growth of bacteria and host response
Name extranal natural surface infections
– Cellulitis – Pharyngitis – Conjunctivitis – Gastroenteritis – Urinary tract infection – Pneumonia
Name internal natural surface infections
Endovascualer - endocarditis, vasculitis
- septic arthritis
- osteomyelitis
- empyema
What are example s of prosthetic surfaces that can become infected
- Intravascular lines
- Peritoneal dialysis catheters
- Prosthetic joints
- Cardiac valves - artificial or derived from animals - put in when patients valves damage
- Pacing wires
- Endovascular grafts
- Ventriculo-peritoneal shunts
What causes native alve endocarditis and prosthetic valve endocarditis >1 year post op
viridans Streptococci Enterococcus faecalis Staph aureus
HACEK group
Candida
What causes prosthetic valve endocarditis <1year post op?
coagulase negative staphylococci
What are ventricular-peritoneal shunts
A ventriculoperitoneal (VP) shunt is a medical device that relieves pressure on the brain caused by fluid accumulation.
VP shunting is a surgical procedure that primarily treats a condition called hydrocephalus. This condition occurs when excess cerebrospinal fluid (CSF) collects in the brain’s ventricles.
Drains liquid into peritoneum
What are causative organisms of prosthetic joint infections
coagulase negative staphylococci - mostly this
Staphylococcus aureus
What is cardia pacing wire endocarditis and what are the causative organisms
Infection of the pace maker wires
coagulase negative staphylococci Staphylococcus aureus
What are the processes n the pathogenesis of infection a surfaces
• Adherence to host cells or prosthetic surface
• Biofilm formation
• Invasion and multiplication
• Host response
– Pyogenic (neutrophils -> pus)
– Granulomatous (fibroblasts, lymphocytes, macrophages -> nodular inflammatory lesions)
What are pili/l
Fimbriae and pili are interchangeable terms used to designate short, hair-like structures on the surfaces of procaryotic cells. Like flagella, they are composed of protein
Bind to surface of host
