Cornyebacteria and Actinomycetes Flashcards
Coryneform
G+
irregular rods
high G-C content
{coryne, arcano,brevi, rthoia, tropheryma}
Corynebacteria
aerobic/facultative ana chinese letters short-chain mycolic (not acid-fast) metachormatic granules (inorganic phosphates that act as E storage) normally opportunisitic
C. diphtheriae sx
diffculty swallowing, epiglottitis, lung infiltrates, exudate, flesh brown pseudomembrane over throat, loss of appetite, hoarseness, URT mucus membranes
2-3d hallmark of respiratory: firm, fleshy grey pseudomembrane – bleeds following attempts to remove/dislodge
fatal airway obstruction
Bull neck
complications: myocarditis, polyneuropathies
C diphtheriae transmission
P2P, oral/respiratory
Respiratory: 1˚ pediatric disease
Cutaneous: common in tropical areas
C. diphtheriae virulence factors
Diptheria toxin:
-AB toxin
-heparin-binding epidermal growth factor
-ADP ribosylation –> EF-2 inhibition, accumulation of cells –> pseudomembrane
(necrotic epithelium embedded w/fibrin and red/white cells
*toxin encoded by lysogenic bacteriophage
*strains w/o phage can still give septicemia, endocarditis
C. diphtheriae dx
More of clinical presentation
- vacc hx, endemic region visit
- pharyngeal characteristics
Cysteine-tellurite blood agar or loeffler’s agar
Elek’s text - antitoxin on paper
PCR - presence of tox gene
C. diphtheriae tx
Antitoxin (early admin.)
-equine serum, make sure no sensitivity to serum sickness
ensure airway clear – Abx: pen, erythro to maintain clearance/prevent carrier status
antimicrobial prophylaxis for close contact (booster vaccinations)
C. diphtheriae vacc
DTaP: combined vacc, 4 doses
Tdap: booster
- reduced [diphtheria & pertussis]
- every 10 years
C. jeikeium
NO PHAGE opportunistic hematologic disorders / intravascular catheters skin of hosp pts V resistant to abx
C. urealyticum
NO PHAGE
uncommon in healthy people
urease producer
strutive calculi/renal stones
@risk: immunosupp, GU, urologic procedures, Abx therapy
resistant to Abx
C. amycolatum
NO PHAGE found on skin not in oropharynx opportunistic misidenitified resistant to Abx
C. ulcerans
Can carry diphtheria gene (PHAGE)
indistinguishable from diphtheria
C. pseudotuberculosis
Can carry diphtheria gene (PHAGE)
rare
Arcanobacterium
G+
irregular rod
colonizer/pathogen
pharyngitis, wound infections (polymicrobial), endocarditis, septicemia
Tx: penicillin, erythro
Brevibacterium
G+ rod skin colonizer cheeselike odor maldorous feet septicemia, osteromyleitis, foreign body infxn
rod-shaped when young, cocci when old
Tx: (b-lac resist) Vanco, tetra, genta
Rothia mucilaginosa
G+ coccoid (not rod)
Cluster growth
Mucoid/sticky –> biofilms
Unpredictable vs abx
Tropheryma whippelii
G+ rod Foamy macrophages acid-schiff positive obligate intracellular parasite Whipple disease -old men, caucasians GI disorder (malabsorption, wt loss, diarrhea) fatty acid deposits in intestine and mesenteric lymphatic tissue arthalgia
disordered IR to persistent bacteria
Tropheryma whippelii dx
Intestinal biopsy
PAS + macropage inclusions
IHC staining
PCR confirmations
Tropheryma whippelii tx
2wk: parenteral pen/strepto
1yr: bactrim
Proprionibacterium
G+ rods non-motile Anaerobic (aerotolerant) ACNE: p. acne and p, propionicum Opportunisitc infections Endodontic abscesses, lacrimal canaliculitis
Proprionibacterium microbio/tx
infect/block sebaceous follicle
increased sebum and androgen prod
leuko migration –> inflammation
Topical Abx: erythro, clinda, tetra
Benzoyl peroxide: increased skin turnover
Nocardia gen/sx
Medium chain mycolic acid (spotty stain) partially acid-fast beading pattern in gram stain external environment-exogenous immunocompromised* filamentous growth
pulmonary, brain (pts w/T cell def), cutaneous, subQ
*mycetoma-anaerobic actinomycetes or fungi
Actinomyces
no mycolic acids not acid-fast uniform gram stain mucous membrane-endogenous molar tooth colonies sulfur granules in plate-cultured isolates
Nocardia pathogenesis
Live in phago for quite a while
cord factor: prevents phagolyso fusion
prevent acidification
protected from O metabolites (catalase/superoxidase mutase)
avoid acid-phosphatase-mediated kiling (host enzyme is utilized as nutrient source)
Nocardia Dx/Tx
Staining (sputum, abscess, CSF)
Will grow on most media
PCR
Tx: bactrim for local, amikacin + carbapenem for systemic
Actinomyces Sx
URT, GI, female GU (NOT on skin)
Poor oral hygiene, aspiration into lungs, abdominal infections
- cervicofacial: lumpy jaw*
- thoracic: pulmonary infiltrate, farmer’s lung* (T3 hypersensitivity rxn)
- abdomen/pelvis: bowel surgeries
- cutaneous/subQ
- brain abscesses
Actinomyces Dx/Tx
Sulfur granules crushed and microscopically examined
Culture (slow) fastidious
PCR
Tx: drain abscess, Pen 6mo-1yr (resistant to a ton of shit)
