M23- Anaerobes Flashcards
(53 cards)
What Neisseria species is commonly isolated from plaque?
N. subflava
where is the location of Neisseria?
Oropharynx, Nasopharynx & occasionally anogenital mucosal membranes
Describe the characteristics of Neisseria.
• Gramnegative
– Diplococci; oval (bean shaped) organisms in pairs or small clumps
– Non motile, do not form endospores
• Aerobes
– Oxidase +ve and usually Catalase +ve
• Produce cytochrome oxidase
• Pathogenic & Non-Pathogenic Species
– 10 species, 2 of which are pathogenic
– Pathogens fastidious (i.e. Cooked blood Agar) non pathogenic species do not require blood & serum
Name the r pathogenic specie of Neisseria.
- N. gonorrhoeae
- N. meningitidis
What diseases does N. gonorrhoeae cause?
– Urethritis (gonorrhea)
– Cervicitis
– Pelvic inflammatory disease
– Pharyngitis
What diseases does N. meningitidis?
– Meningitis
– Bacteremia
– Pnuemonia
Describe N. gonorrhea.
– frequent cause of STD (Peak 20-24 yrs in Males, 16-19 yrs in females)
– Sensitive to desiccation, fatty acids and temperature
– Acute & chronic pathology
Name the key virulence factors of gonorrhea.
– Simple Capsule & Pili which extend through capsule.
( Phase variation of Pili via gene conversion)
– Pili & Opa Proteins facilitate adhesion (urethra, rectum, cervix, pharynx, conjunctiva)
– Pili enable organism to resist phagocytosis
– IgA protease produced
What makes it hard to make an effective vaccine for gonorrhea?
phase variation
-changes amino acid antigens
Describe the infection of gonorrhea.
– Localised infection of genital urinary tract producing pus, tissue invasion & localised inflammation.
– Acute & easier to diagnose in Males
– Asymptomatic carriers act as reservoir (female more often than male)
– Pharyngitis; oral-genital contact symptoms mimic a mild viral or streptococcal sore throat.
– Non-venereal seen in newborn as conjunctivitis
Describe the identification of gonorrhea.
– Swabs of infected material
– Gram stain,intracellular Gm-ve diplococci
– Cooked Blood Agar
– Oxidase+ve,glucose+ve,-ve maltose & sucrose
Describe the treatment of gonorrhea.
Penicillin (resistance increasing problem)
-threat level is urgent
what is the oral presentation of gonorrhea?
usually asymptomatic
what is meningitis?
Infection & inflammation of membranes covering the
brain & spinal cord (meninges & CSF)
-bacterial and viral
what organisms can cause meningitis?
N. meningitidis, S.pnuemoniae & H.influenza
what is the only organism that causes large scale epidemics of meningitis?
N. meningitidis
Describe N. meningitidis and its spread.
– Acute suppurative Meningitis
– Meningococcemia (severe blood infection)
– Reservoir nasopharynx of 5-10% of the population
– Spread; infected carrier; via respiratory secretions to case
– Not highly communicable but crowded conditions concentrate carriers e.g. Dormitory, School, Prison, University
– Greatest threat to children <5 year old
Describe features of the main disease of meningitis?
-Aerosolisation of respiratory tract secretions, (winter & early spring)
– Colonisation & penetration of epithelium
– 2 to 10 day incubation
– Possible mild disease, fever & non specific symptoms
– Absence of effective host immune response, severe disease
– Abrupt onset, malaise, high fever (>40 ̊C) & possible rash (bloodstream)
– Progresses to headache, stiff neck, & sensitivity to bright lights
– Fever, Vomiting & diarrhoea, confusion/drowsiness, difficulty supporting own weight.
– Coma can occur within a few hours (e.g. 4 hours).
Describe the identification of meningitis.
- Non-motile, Gm -Ve diplococcus (kidney bean shape)
- Cultured on CBA or Chocolate agar with increased CO2 (48 hrs)
- Oxidase +ve, Ferments Glucose & Maltose
- 12 serogroups A, B & C responsible for 90% of the disease
- Diagnosis through cerebrospinal fluid (CSF) and serogroup specific anticapsular antibody reactions
Describe the treatment and control of meningitis.
• Suspected Meningitis is a medical emergency – (cannot wait for definitive diagnosis)
• High fever, headache & rash treated with Large intra-veinous doses of Penicillin G or Ampicillin
• Cefotaxmine or Spectinomycin if resistant
• Prophylaxis Rifampicin (e.g. family members)
• Meningococcal ACWY
– 99% drop in cases (955 UK deaths to around 13)
• Meningococcal B – new vaccine for 73% of these European strains
If family members have previously had it, how does this effect the risk of meningitis?
Increases the risk
Give 4 types of meningitis.
- MenB - 53% - 396 cases - 40% infants and toddlers
- MenW - 30% - 225 cases - 62%> 25
- MenC - 5% - 37 cases - 59%>25
- MenY - 11% - 80 cases - 79% >25
what gram +ve cocci causes caries and actinomyocosis?
Actinomyces species
What gram -ve cocci cause periodontal infections?
- Fusobacterium species
- Prevotella species
- bacteriodes
