2.3 Gram Positive Bacilli-GPB

Diphtheria Toxin synthesis is regulated by __?

diphtheria toxin repressor (DTxR)

Most species of Corynebacterium diphtheriae ferment carbohydrate to____?

lactic acid

tox gene is introduced into strains of C. diphtheriae by___? 谁将tox gene 导入白喉杆菌菌株

lysogenic bacteriophage β-phage 溶酶原噬菌体β-噬菌体

Does Corynebacterium diphtheriae needed to be tested for exotoxin?

yes

How to Identification of L. monocytogenes from other listeria species?

• Serological and molecular typing • Pulsed field gel electrophoresis (PFGE)脉冲场凝胶电泳 • Whole genome sequence analysis

Clinical presentation of diphtheria depends on what?

1. 'Site' of infection 2. 'Immune status' of the patient 3. 'Virulence' of the organism

Which is NOT True about Treatment, Prevention and Control of L. monocytogenes? A. Have Vaccine before you get the disease. B. Can be treat with Gentamicin+penicillin or Gentamicin+ampicillin C. You should Avoid eating raw or partially cooked foods D. Trimethoprim-sulfamethoxazole is bactericidal to L. monocytogenes E. Its easy to Prevent and control L. monocytogenes

A.E Vaccine not available Prevention and control difficult

Which is NOT true about the treatment of Erysipelothrix rhusiopathiae? A. Susceptible to penicillin B. If penicillin allergy: Use Ciprofloxacin/ Clindamycin- localized cutaneous infection. C. If penicillin allergy: Use Ciprofloxacin/ Clindamycin- localized disseminated infection. D. Vaccination used to control disease in swine

C For patients with penicillin allergy, Ceftriaxone 头孢曲松钠/ Imipenem亚胺培南- for disseminated infections

Which is NOT true about the treatment of Corynebacterium diphtheriae? A. Antitoxin B. Antibiotics: Erythromycin, penicillin G C. Does not have Vaccines for this D. Immunization: DTaP, Tdap

C 可以有疫苗

What kind of culture that Erysipelothrix rhusiopathiae will grow?

Conventional lab media, incubated in presence of 5%-10% CO2, grows slow

A pt get sick, Lab shows that the major Virulence factors is Diphtheria Toxin which can inhibits protein synthesis. 检测患者基因：has 'tox gene' which is responsible for toxin production. what would be the species?

Corynebacterium diphtheriae

A pt, Lab shows a species: G+ pleomorphic rods which is NOT acid fast. Aerobic or facultatively anaerobic. Catalase positive, Non motile. Has cell wall. what do you suppose that the species would be?

Corynebacterium diphtheriae

Which kind of species can use Microscopy method to diagnosis. Like Metachromatic granules stained with methylene blue?

Corynebacterium diphtheriae (G+)

a doctor Collected culture of a pt form his nasopharynx and throat. Then doctor can use either Cysteine-tellurite blood agar (CTBA); Tinsdale medium or Colistine nalidixic agar (CNA) to make a conclusion. with Presence of cysteinase, Absence of pyrazinamidase. what would be the species?

Corynebacterium diphtheriae (G+)

a pt, Cutaneous diesase, she said that she has this symptom through skin contact with other infected persons. Impair on skin with break skin, they can enter subcutaneous tissue. A papule can develops into nonhealing ulcer too. what would be the species?

Corynebacterium diphtheriae (G+)

a pt, has Respiratory disease sore throat, malaise, exudative pharyngitis, low grade fever where exudate evolves into a thick pseudomembrane at epithelial cells of pharynx or adjustment surface. Symptoms appear 2-4 days after inoculation. complications could be Myocarditis (congestive heart failure, cardiac arrhythmias and death) and Neurotoxicity (oculomotor and ciliary paralysis) what would be the species?

Corynebacterium diphtheriae (G+)

Which is NOT true about Listeria monocytogenes? A. Isolated in soil, water and vegetation. B. Disease associated with consumption of contaminated products C. Listeria monocytogenes can be affect variety of animals including humans D. Listeria monocytogenes can not pass Transplacental E. Sporadic cases and epidemics occur throughout the year

D Listeria monocytogenes can have Transplacental spread from mother to neonates

a pt keep Diarrhea, Doctor said that was due to Bacteria multiplies in host intestinal tract and releases enterotoxin. Lab test it is a Heat 'labile' enterotoxin. The pt keep like this for 20-36 hrs. Pts associated with nausea, abdominal cramps. what would be the disease, and what would be the species?

Diarrheal form Gastroenteritis; Bacillus cereus Heat labile

Infection of Listeria monocytogenes in pregnant women usually during what time?

During third trimester when cellular immunity is impaired

How Listeria monocytogenes affect neonatal?

Early onset disease • Acquired transplacentally in utero • Can result in abortion, still birth or premature birth Late onset disease • Acquired at or soon after birth • Occurs 2-3 weeks after birth in form of meningitis

What can we use to detect tox gene?

Elek test (immune diffusion assay)

a pt keep Vomiting, Doctor said that was due to consumption of contaminated rice. Intoxication due to toxin, Lab test it is a Heat 'stable' enterotoxin. The pt keep like this for 8-10 hrs. what would be the disease, and what would be the species?

Emetic form Gastroenteritis; Bacillus cereus Heat stable

A pt has Inflammatory skin lesion, he experiment burning or throbbing sensation, he went to the hospital, and the doctors says: you have a species. Lab: Non spore forming rods; Microaerophilic; with Motility test: Negative. Catalase test: Negative! what would be the species?

Erysipelothrix rhusiopathiae

A pt have Systemic signs like fever and arthralgia, Characterized by development of lesions either in the general area of the initial lesion or at other skin lesions. Lab: Non spore forming rods; Microaerophilic; Motility test: Negative. Catalase test: Negative! what would be the species?

Erysipelothrix rhusiopathiae

a pt has virulence factors like: 1. Neuraminidase: attachment and penetration into epithelial cells 2. Polysaccharide like capsule: antiphagocytic what would be the species?

Erysipelothrix rhusiopathiae

what would be the species? 1. G+ 2. Non spore forming rods 3. Microaerophilic 微量需氧 4. particularly in swine and turkey, can be in soil and water 5. Uncommon in US 6. Occupational disease of butchers, meat processors, farmers, poultry workers, fish handlers and veterinarians

Erysipelothrix rhusiopathiae

How can we Distinguishes Erysipelothrix rhusiopathiae from Listeria

Erysipelothrix rhusiopathiae: 1. Motility test: Negative 2. Catalase test: Negative

T/F We can use antimicrobials to treat gastroenteritis.

F No antimicrobials for gastroenteritis

a pt see Virulence factors of InIA, InIB; LLO; PLC;ActA protein. what would be the species?

Listeria monocytogenes AcA protein: mediates actin mediated intracellular motility

A pt come, lab shows Gram positive rods, Weak β-hemolytic. Facultative anaerobic, Broad temperature range (1-45C), Resistant to high concentration of salt, Motile at room temperature, Facultative intracellular pathogen. what would be the species?

Listeria monocytogenes The most significant human pathogen

what should be the most common cause of disseminated listeria infection in adults?

Meningitis Suspected in pregnant women, patients with organ transplant and cancer

what antimicrobials can we sue to treat infections by Bacillus cereus?

Vancomycin, clindamycin, ciprofloxacin and gentamycin

what does the cell wall of Corynebacterium diphtheriae contains?

arabinose galactose mesodiaminopimelic acid (meso-DAP) (in most species) short chain mycolic acid

Which is NOT true about Corynebacterium diphtheriae? A. it can NOT spread through skin touch B. it can spread through respiratory droplets C. Humans are reservoirs D. Uncommon in United states

A. can spread through skin

what would be the 3 Functional regions exist on the Diphtheria toxin molecule

1. A catalytic binding region on A subunit 2/3. A receptor binding region and A translocation region on the B subunit

Listeria monocytogenes Pathogenesis process:

1. Attachment 2. Phagosomal lysis 3. Replication 4. Expression of ActA protein 5. Actin based motility 6. Cell to cell spread P16课件有图片

Corynebacterium diphtheriae Pathogenesis

1. Diphtheria toxin 'attaches' the host cells using receptor binding region on the 'B subunit' 2. Translocation region on the 'B subunit' is inserted into the endodermal membrane 3. A-B exotoxin gets 'pinocytosed' 4. A is released 5. A subunit 'terminates' the host cell 'protein synthesis' by inactivating elongation' factor-2' (EF-2) P26课件有图

3 primary forms of human diseases caused by Erysipelothrix rhusiopathiae are ?

1. Erysipeloid 2. Generalized cutaneous disease 3. Septicemia (uncommon,But when present, frequently associated with endocarditis)

Diagnosis of Listeria monocytogenes

1. Microscopy-Gram staining 2. Culture • Cold enrichment • Sheep blood agar- beta hemolysis • CAMP test (CAMP= diffusible extracellular protein) • Motility test

what other Virulence factors that the Bacillus cereus would have? what will these lead to?

1. Necrotic toxin (a heat labile enterotoxin) 2. Cereolysin (a potent hemolysin) 3. Phospholipase-C (a potent lectinase) All will lead to Ocular infections

what kind of people have more risk for Bacillus cereus?

1. Those who consume 'contaminated food' with bacterium 2.Those with 'penetrating' injuries 3. Those who receive IV injections 4. Immunocompromised patients

This 50,300 Da protein (lysogenic bacteriophage β-phage) is a classic example of ___?

A-B exotoxin

A pt get Gastroenteritis, lab test that would be Heat stable (or labile) enterotoxin. The species that is Gram Positive rods, Spore forming, Motile, Hemolytic. what would be the species?

Bacillus cereus

A pt, after traumatic, penetrating injuries of the eye with soil contaminated object, can result in Complete eye loss within 48 hrs. what would be the disease, and what would be the species?

Ocular infections Bacillus cereus