Question

Please give the genus and species for each question.

1. The colonies are typically large, gray-white opaque colonies on blood agar. Some strains are beta hemolytic. On MacConkey agar the colonies appear red from fermentation of lactose in the medium. The bacterial cells are gram-negative straight rods. The biochemical reactions are indole positive, methyl red positive, voges proskauer negative and citrate negative. The microbe is (genus and species):

16. A 38-year-old man in Alabama developed bilateral paresthesia and pain in his ears, headache, sore throat, and anorexia. These symptoms persisted and later were accompanied by fever, difficulty swallowing, confusion, and tremor. He was admitted to the hospital with a temperature of 105 F, nuchal rigidity, confusion, agitation, and spasmodic tremors. Physical examination admission revealed dysarthria, dysphagia, pharyngeal paralysis, and drooling. Stimulation of the patient precipitated spasms with spontaneous flexion of all extremities. A lumbar puncture revealed no marked abnormalities. Seven days later, the patient had pharyngeal and laryngeal spasms, subsequent cyanosis, and suffered a respiratory arrest; he was resuscitated immediately. Reviewing the patient’s history he had been bitten on the right ear by a bat four weeks prior to admission. The bat had escaped and the patient had sought medical care. Over the next few days, the patient lapsed into a coma. Neurologic examination revealed facial paralysis, generalized hyporeflexia, and response to only deep pain. No other focal abnormalities were present. Initially the patient was treated with diphenylhydantoin, diazepam, and chlorpromazine. Once the coma ensued, the sedatives were discontinued. Proteinuria, hypothermia and hypoxia subsequently developed. Despite intensive respiratory care, antibiotics, postural drainage, use of bronchodilators, and vigorous suctioning, hypoxia persisted. The patient developed a pneumothorax, had a cardiorespiratory arrest and died. The microbe is (genus and species):

30. a 7-year-old boy was brought to your office for evaluation of a sore throat and fever which he had for about 5 days. He is the son of parents who immigrated to the United States from Moscow 6 months ago. He has not had much medical care in his life, and his immunization status is unknown. He is anxious, tachypneic, and appears sick. His temperature is 101.5 F and his voice is hoarse. His tonsils and pharynx are red and swollen with a grey membrane coating the tonsils, uvula and soft palate. He has lymphadenopathy. His lungs are clear. He is transferred to a local children’s hospital with the presumptive diagnosis of:

Answer 1

1, The given characteristics are

Gram result	Gram negtaive, rod
Hemolysis	gamma hemolysis/ some strains may show beta hemolysis
lactose fermentation	positive
Indole	positive
methyl red	positive
vp	negative
citrate	negative

The bacteria belongs to the family lactose fermenting Enterobacteriaceae. The bacteria that shows these characters as tabulated is Eschericia coli. Some strains of E coli isolated from patients sample shows beta hemolysis pattern. It is a well known lactose fermenting bacteria.

16. Rabies virus is the causative agent for the information provided in the case study. Rabies virus infects animals such as dogs, bats, foxes, raccoons, etc. the virus is transmitted to humans when they come in contact with the saliva of the infected animal by licking, biting, etc. The target of the virus is to reach the brain tissues. From the wound through which it enters the body, by retrograde axonal transport it reaches the brain tissues where it multiplies rapidly and infects other parts of the body. Rabies is 100% fatal. The symptoms such as confusion, dysarthria, dysphagia,, drooling, facial paralysis are important symptoms of rabes infection.

30, the given case study deals about the infection caused by Corynebacterium diptheriae, the causative agent of diptheria. It resembles sore throat, but is fatal if not treated properly. Vaccines has decreased the risk of infection from diphtheria. Improper vaccine and immunisation schedules may lead to this infection. The pathogen is transmitted through air droplets.

Diphtheria infection is known for its formation of pseudomembrane- gray coloured membrane in throat and tonsils. Swollen glands- lymphoadenopathy is also seen in infected patients. SInce the child has shown all these symptoms, the presumptive diagnosis will be diphtheria