Listeria and Erysipelothrix Ali Somily MD

Classification – Genus listeria – Soil, water, and vegetation – Many species? L.ivanovia ( animal) L.innocua ( food) L.monocytogen – Pathogenic to human

Microbiology Specimen – Blood – CSF – Amniotic fluid – Non sterile site Vagina Stool spp not swab – 1-5% carrier Media – BAP – CHO Temp – Cold enrichment for several days

Microbiology Smear – Aerobic non spore forming short G+ve B or coccobacilli – Rounded end, singly or short chain In CSF might mimic – Enterococcus – S.pneumoniae – Corynebacterium – Haemophilus Culture – Catalase +ve – H2S –ve

Listeria monocytogenes

Clinical syndromes Epidemiology – Summer month – Epidemic& sporadic – Dairy product & meat Predisposing factors – Newborn – Elderly – Pregnancy – Cell mediated Abn. AIDS Lymphoma Transplant Diseases Septcemia CNS (meningitis, encephalitis) Amnionitis  Preg. Termination

Life Cycle

Treatment Ampicillin not cefotaxime

Erysipelothrixs rhusiopathiae Genus Erysipelothrixs – Two spp E. rhusiopathiae ( only pathogen) E.tonsillarum

Microbiology Smear – Gram positive nonspore forming short baccilli, – Rounded end singly or short chain – Slender and long filaments

Microbiology All -ve – Catalase – Oxidase H2S +ve

E. rhusiopathiae Carried by animal (fish, Swine) Cutaneous infection  Erysipeloid – Skin abrasion, injury bite from infected animal. – Hand of veterinarians butchers and fish handlers – Generalized rare – I’C (bacteremia and endocarditis)

Erysipeloid

Corynebacterium

Coryneform Aerobic non spore forming gram positive bacilli Coryne= club  coynebacterium >40 spp devided into 3 groups – Group I human and animal – Group II plant – Group III nonpathogenic C.dipthteriae Archanobacterium Gardnerella

Microbiology Smear – Vary from coccoid to rod.Clubbed stain unevenly Arrange in V-shape Chinese letter.Rod in parallel or palisade formation C.diphtheria – Nasopharyngeal swab – BAP – Selective media Tellurite medium( black colonies) – Tinsdale – Cystine –tellurite BAP – Sensitive to K tellurite may not grow – Loeffler’ s media not as primary media  metachromatic granules

Identification – Catalase +VE – APICoryne – RapID CB plus Toxigenicity – Elek test reference lab – Antisera on strep under special media – Neg and pos control in addition to the patientsample – Incubate 37d – 45 o line of precipitation – Reincubate 72 hr if negative

C. diphtheriae

VARIENT OF C.DIPHTHERIA: 1.GRAVIS 2.MITIS 3.INTERMEDIUS

COLONIAL MORPHOLOGY

TINSDAL MEDIA

(i) C. diphtheriae biotype gravis colonies on a Tinsdale agar plate

Recovery of Miscellaneous Pathogens From Throat Cultures Pseudomembrane of the pharynx Occasionally of the skin. Toxigenic strains of Corynebacterium. To confirm a clinical diagnosis of diphtheria, the strain isolated diphtheriae. The disease is characterized must be shown to produce toxin.

Clinical infections Respiratory and cutaneous Uncommon in North America and Western Europe. Humans are the only natural hosts for C. diphtheriae. Carried in the upper respiratory tract Spread by droplet infection or hand-tomouth contact. IP 2 to 5 days. Low-grade fever, malaise, and a mild sore throat. Tonsils or pharynx.

Rapidly multiply on the epithelial cells and trigger an inflammatory reaction. The infecting toxigenic strain of C. diphtheriae produces toxin locally Tissue necrosis and exudate formation. Cell necrosis and exudate forms a very tough gray to white pseudomembrane, which attaches to the tissues. Spread downward into the larynx and trachea. Suffocation if the membrane spreads

Blocks the air passage or if it is dislodged The toxin also is absorbed and produces a variety of systemic effects. – Kidneys, heart, and nervous system Death often is a result of cardiac failure. Another effect of the toxin is a demyelinating peripheral neuritis  paralysis following the acute illness Mortality of 5-10%, highest in very young and old. Erythromycin is the drug used for penicillin-sensitive individuals.

Antitoxin Produced in horses. Hypersensitivity to horse serum precludes its administration. 10% allergic reaction to the horse serum. Antibiotics have no effect on toxin Eliminate the focus of infection as well as prevent the spread of the organism. The drug of choice is penicillin.

Nonrespiratory sites – Cutaneous Systemically, but systemic complications are less common than from upper respiratory infections.

The routine immunization Diphtheria, pertussis, tetanus, polio : – 2,4,6,18 months, 4 yrs Routine immunization since 1950's - one or two cases a year, classic diptheria rare Since 1990, thousands of cases in former Soviet Union (mortality 3-23%)

Diptheria-vaccine Toxoid; cell-free detoxified diphtheria toxin protects against the systemic effects of toxin but not against local infection/colonization

Diphtheria toxin/Zoonotic C.ulceran – Bovine mastitis C.pseudotuberculosis – Animal(sheep) LNs