Streptococci Flashcards
Streptococcus is gram negative. True or false?
False
gram positive
What are the virulence factors of Strep?
Bacterial capsule
Exotoxin production
Immune invasion
Dissemination
What infections are caused by GAS?
sore throat, impetigo, cellulitis, scarlet fever, necrotizing fasciitis
Strep is present in oral microbiota. True or false?
True
Strep throat is usually transmitted in winter. True or false?
False
Spring and autumn
What are the signs and symptoms of strep throat?
Swollen tonsils
Discomfort when swallowing liquids
What are three ways in which strep throat can be diagnosed?
Physical examination
Throat swabs of affected tissue
Blood test - antibodies
Often no treatment is needed for strep throat. True or false?
True, give OTC analgesics, antibacterial lozenges, sprays, mouthwashes.
If they have fever and pain give AB such as Phenoxymethylpenicillin or clarithromycin
Rheumatic heart disease is a complication of GAS. True or false?
True
What are some complications of GAS?
Necrotising fasciitis, Strep toxic shock syndrome, acute rheumatic fever
What is cellulitis?
an acute bacterial infection of the skin that involves dermis and subcutaneous tissues
IV drug use can cause cellulitis. True or false?
True
Patients with chicken pox are prone to cellulitis. True or false?
True
Obese patients are not at risk of cellulitis. True or false?
False
GAS can be carried in the vagina and anus. True or false?
True
What are the signs and symptoms of cellulitis?
Skin becomes red, hot, swollen and tender
Commonly affects the legs
Blisters
Cellulitis patients need to be referred to hospital. Why?
They need IV antibiotics
What are some danger signs of cellulitis that would indicate referral to hospital is needed?
Spreading of redness in an area
High temp of 38+
Change in mental state
Nausea or vomiting
Rapid heartbeat & breathing
What are the three ways in which cellulitis is diagnosed?
Blood tests
Skin swab
Physical examination
How is a mild infection with cellulitis treated?
pain management, adequate fluid intake, 7-14 day oral AB at home eg phenoxymethylpenicillin
How is an advanced infection of cellulitis treated?
Hospital admission for IV AB – benzylpenicillin
What are some complications of cellulitis?
Septicaemia, necrotising fasciitis, facial cellulitis
In cellulitis how does the causative agent enter body?
through breaks in skin from cut, burn, bite, skin ulcer, etc
What are some differential diagnoses for strep throat?
glandular fever (viral infection), cancer (persistent sore throat), quinsy (abscess, painful collection of pus), epiglottitis (inflammation of epiglottis)
What are some danger symptoms of strep throat?
difficulty breathing, obstruction of airways, high fever etc.
Scarlet fever is more common at what age and in what season?
aged 10 or younger and in winter/spring months
What are the initial symptoms of scarlet fever?
initial flu-like symptoms such as high temp, sore throat and swollen neck glands
What are some later symptoms of scarlet fever?
eventual rash development post fever, coarse rash and skin may peel. May also develop strawberry tongue 48 hours post fever. White coating may disappear to form red strawberry tongue.
How is scarlet fever managed/treated?
If suspected but person not unwell give Phenoxymethyl penicillin (PenV) & if allergic to penicillin give azithromycin, also manage pain and itching with paracetamol/ibuprofen and calamine lotion/antihistamines
Describe structure of streptococcus pneumoniae
gram positive diplococcus, non-motile
What are some risk factors for pneumonia?
smoking, contact with children, age and alcohol abuse
Pneumococci can be transiently carried in what part of the body?
Nasopharynx
How long does the carrier state persist?
14 days after initial exposure but is typically asymptomatic
In some cases, there is a switch from carrier to invasive infection, what can this cause?
initially mild irritation of upper airway, fever, malaise, dyspnoea, productive cough
In order to switch, SP needs virulence factors, describe some of them
Polysaccharide capsule which works through a charge effect, the SP virulence it associated with the capsule’s thickness
high surface charge interferes with phagocyte interactions and reduces complement deposition at surface of bacteria
pneumolysin is a pore forming toxin produced by lysed Sp cells, causes induction of cytokine release and can damage cilia movement
Severity assessment of CAP is determined through clinical judgement and the CRB-65 scoring, explain what the CRB scoring is
1 point given for each of the following prognostic features: confusion, respiratory rate (>/= 30 breaths/min), BP (= 60 diastolic of <90 systolic ) & Age (>/= 65)
How would a low score be managed?
community management, amoxicillin, alternative options are azithromycin or clarithromycin (if pen allergy)
How would a moderate score be managed?
consider hospital assessment, amoxicillin + clarithromycin (if atypical suspected) or erythromycin (in pregnancy)
How would a sever score be managed?
urgent hospital admission, IV antibiotics: co-amoxiclav with clarithromycin or erythromycin (if pregnant)
