Microbiology Exam 4 Questions with 100% Accurate Answers, Exams of Microbiology

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Microbiology Exam 4 Questions with 100% Accurate Answers

1. What are some general characteristic of the nonfermenters?: Found in most environments, prefer aerobic environments, resistant to many antibiotics, rarely a part of host microbiota 2.What are the general biochemical reactions of the nonfermenters?: Oxidase +, fail to acidify OF media when overlaid with mineral oil, cannot acidify TSI agar butts Some organisms are oxidizers, some are asaccharolytic
2. What are the 3 common tests used to look for nonfermenters?: Growth on MAC agar, oxidase, glucose OF test
3. What are the most common nonfermenters seen in the clinical lab- oratory?: Pseudomonas aeruginosa, Acinetobacter spp., Burkholderia spp., Stenotrophomonas maltophilia 5.What are some general characteristics of the Pseudomonas genus?: Gram

• bacilli, strict aerobes, motile, oxidase and catalase +, oxidizes carbohydrates, usually grows on MAC

6. Where is P. aeruginosa typically found?: Moist environments (pools, hot

tubs, catheters, humidifiers)

7. What pigment does P. aeruginosa produce that fluoresces under UV light?- : Pyoverdin

8. What illnesses can be caused by P. aeruginosa?: Nosocomial respiratory tract infections, LRT infections in patients with cystic fibrosis, wound infections, nosocomial UTIs 9.What patients can quickly become colonized by P. aeruginosa?: Patients who are mechanically ventilated 10.What is the colony morphology of P. aeruginosa?: Flat, spreading colonies with a characteristic metallic sheen. Fruity, grapelike odor 11.What are some biochemical characteristics that can be used to identify P. aeruginosa?: Oxidase +, catalase +, B-hemolysis, ADH +, citrate + 12.What agar is selective and differential for P. aeruginosa?: Cetrimide agar 13.What can be used to treat P. aeruginosa?: Aminoglycosides, semisynthetic penicillins, third and fourth generation cephalosporins 14.What characteristics can be used to differentiate P. fluorescens and P. putida from P. aeruginosa?: Does not produce pyocyanin, cannot reduce nitrate

Achro- mobacter species?: Grow well on most media, nonpigmented, flagella 24.What are some general biochemical reactions of Chromobacterium vi- olaceum?: Fermentative, gram - bacilli, oxidase variable, motile, violet pigment, catalase +, indole -

25. What are some general biochemical reactions of Flavobacteriaceae?: - Lavender-green discoloration of media, DNAse +, oxidase +, weakly indole + 26.What are some factors that can predispose a patient to an infection by an anaerobe?: Trauma, vascular stasis, entry to a reduced environment 27.What are some general characteristics of the Clostridium spp.?: Gram

• bacilli, anaerobe, spore-forming, mostly exogenous infections 28.What species of Clostridium causes endogenous infections?: C. difficile 29.What diseases can be caused by Clostridium?: Antibiotic-associated diar- rhea, colitis, tetanus, gas gangrene, botulism, food poisoning 30.What causes type A C. perfringens food poisoning?: Ingestion of the C. perfringens enterotoxin 31.Whta causes type C C. perfringens food poisoning?: Infection of C. perfrin- gens strain that produces alpha or beta toxins

32.What organism causes botulism?: C. botulinum 33.What botulism toxins are associated with human disease?: A, B, E 34.What does the botulism toxin do?: Causes paralysis 35.What are some sources of botulism?: Home-canned vegetables, home- cured meats, other preserved foods 36.How is botulism treated?: Antitoxin and supportive care 37.What food source commonly causes infant botulism?: Honey 38.What is the causative agent of tetanus?: Clostridium tetani 39.What virulence factor of C. tetani causes tetanus symptoms?: Tetanospas- min neurotoxin 40.What are some symptoms of tetanus?: Muscular rigidity of the jaw, neck, and lumbar region 41.What is myonecrosis, and what organism is the most common cause?: An anaerobic infection deep inside the tissue; C. perfringens 42.What toxin attributes to tissue necrosis in myonecrosis?: Alpha toxin 43.When does C. diff cause antibiotic-associated diarrhea?: When normal flora are destroyed by antimicrobials that C. diff isn't affected by 44.What are the 2 C. diff toxins?: A: enterotoxin B: cytotoxin

54.What tools can be used to provide an air-free environment for an anaer- obe?: Glove boxes, anaerobe jars, biobags

55. What presumptive ID can we make if we find an anaerobic gram + bacilli?- : Clostridium spp. 56. What presumptive ID can we make if we find an anaerobic gram - bacilli?- : Fusobacterium spp. 57. What presumptive ID can we make if we find an anaerobic gram - cocci?- : Veillonella 58.What presumptive ID can we make if we find an anaerobic gram - coc- cobacilli?: Bacteroides, Porphyromonas, Prevotella 59.What are the 3 main media used to set up anaerobic cultures?: Anaerobic blood agar, Kanamycin-vancomycin-laked blood agar, anaerobic broth 60.What are the gas levels of H, CO2, and N2 in an anaerobic chamber?: H -

5-10% CO2 -> 5-10% N2 -> 80-90% 61.What does a catalyst do in an anaerobic chamber?: Removes any

residual oxygen 62.What does a desiccant do in an anaerobic chamber?: Absorbs excess water produced by the catalyst 63.What does an indicator do in an anaerobic chamber?: An indicator that changes color when oxygen is present 64.What are some indications that an anaerobe is present in a culture?: Foul odor, characteristic colony morphology on anaerobic plates but not aerobic plates, double zone of hemolysis, brick red fluorescence 65.What anaerobes fluoresce under UV light?: Porphyromonas spp., Prevotella spp., Fusobacterium nucleatum, C. diff, Veillonella spp.

66. What is a unique characteristic of C. perfringens on a blood agar plate?: - Double zone of hemolysis 67.What agar is selective for C. diff?: Cycloserine-cefoxitin-fructose agar (CCFA) 68.What anaerobic gram + cocci has black colonies?: Peptococcus niger 69.What are the 5 ways an anaerobic infection can be treated?: Surgery, hyperbaric oxygen, antimicrobials, antitoxins, fecal microbiota transplant (FMT)

severe headache, muscle pain, weakness 78.What animal causes B. recurrentis endemic relapsing fever?: Ticks of the genus Ornithodores 79.What animal causes B. recurrentis epidemic relapsing fever?: Body louse Pediculus humanus (lice) 80.How is B. recurrentis diagnosed?: Direct observation of spirochetes in the blood 81.How is B. recurrentis treated?: Tetracyclines 82.What are some virulence factors of B. burgdorferi sensu lato?: Ability to act as a protease, complement evasion, cytokine stimulation 83.What disease is caused by B. burgdorferi sensu lato?: Lyme disease 84.What are the symptoms of stage 1 of Lyme disease?: "Bullseye" erythema migrans at the site of the tick bite 85.What are the symptoms of stage 2 of Lyme disease?: Secondary skin le- sions, migratory joint and bone pain, alarming neurologic and cardiac pathology, splenomegaly, severe malaise and fatigue 86.What are the symptoms of stage 3 of Lyme disease?: Cardiac, muscu- loskeletal, and neurological issues. Arthritis is most common symptom

87.What organism transmits Lyme disease?: Ixodes tick 88.What are the serologic tests for Lyme disease?: Initial IFA or EIA test, antibody confirmation test 89.What antibiotics are used to treat Lyme disease?: Early stages - macrolides, doxycycline, amoxicillin Late stages - ceftriaxone 90.What are some virulence factors of syphilis?: Penetrates intact mucous membranes, crosses placenta, antigenic variation 91.What organism causes syphilis?: Treponema pallidum subsp. pallidum 92.How is syphilis transmitted?: Sexual contact 93.What are some symptoms of the primary stage of syphilis?: Primary chan- cre at infection site, erythematous lesion 94.What are some symptoms of the secondary stage of syphilis?: Fever, sore throat, generalized lymphadenopathy, headache, lesions of the mucous membrane, rash 95.What are the 3 fates of the tertiary stage of syphilis?: 1) Biological cure, loses serological activity

2. Remains latent for life, but has reactive serology
3. Develops tertiary or late syphilis later in life

106. What urogenital diseases in women can be caused by C. trachomatis?: - Cervicitis, endometriosis, salpingitis, proctitis

107. What urogenital diseases in men can be caused by C. trachomatis?: Non- gonococcal urethritis, epididymitis, prostatitis, proctitis
108. What is Reiter syndrome?: Reactive arthritis believed to be caused by C. trachomatis
109. What are some symptoms of Chlamydia in newborns?: Conjunctivitis, na- sopharyngeal infections, pneumonia, otitis media
110. What cell lines are used for the detection of chlamydiae?: McCoy, HeLa, buffalo green monkey kidney
111. What illnesses can be caused by C. pneumoniae?: Sinusitis, pharyngitis, acute respiratory disease, bronchitis, pneumonia
112. What are the symptoms of the 2 phases of C. pneumoniae?: Phase 1 - prolonged sore throat, flulike symptoms Phase 2 - pneumonia and bronchitis without fever
113. Where is C. psittaci found?: In avian species
114. How can humans be infected with C. psittaci?: Inhalation of the

bacteria after contact with infected poultry

115. What are some general characteristics of Rickettsiaceae?: Arthro- pod-borne, obligate intracellular pathogens, grows only in cytoplasm
116. What are the 3 groups of Rickettsiae?: Typhus, spotted fever, transitional
117. What species of Rickettsiae are considered bioterrorism agents?: R. prowazekii, R. typhi, R. rickettsii, R. conorii
118. What organisms causes rocky mountain spotted fever?: R. rickettsii
119. What are the symptoms of an initial rocky mountain spotted fever infec- tion?: Fever, headache, myalgia, nausea, vomiting, rash on ankles and wrists
120. What are some symptoms of disseminated rocky mountain spotted fever?: Vasculitis, pneumonitis, CNS manifestations, myocarditis, hypotension, DIC
121. What organism causes Boutonneuse fever?: R. conorii
122. What organism causes endemic/murine typhus?: R. typhi
123. What organism causes epidemic louseborne typhus/Brill-Zinsser dis- ease?: R. prowazekii

134. What are the symptoms of Q fever?: High fever, headaches, myalgia, arthral- gia, cough
135. What are some lab values that are affected by Q fever?: Elevated liver enzymes, increased sedimentation rate, thrombocytopenia
136. How is Q fever diagnosed?: DFA of infected tissue, NAATs
137. What are some general characteristics of Mycoplasma?: Lack a cell wall, pleomorphic, difficult to gram stain, resistant to cell wall antibiotics
138. How does Mycoplasma look on an agar plate?: Center imbedded below agar surface, "fried egg" appearance
139. How is Mycoplasma transmitted?: Sexual contact, respiratory droplets, fomites
140. What illnesses can M. pneumoniae cause?: Bronchitis, pharyngitis, walking pneumonia 141. What are some symptoms of M. pneumoniae walking pneumonia?: - Headache, low-grade fever, malaise, anorexia, sore throat, dry cough, earaches
141. What area of the body can M. hominis infect?: Lower urogenital

tract

143. What illnesses are associated with M. hominis?: Salpingitis, pyelonephritis, pelvic inflammatory disease, postpartum fevers
144. Where does Ureaplasma urealyticum infect?: Urogenital tract
145. What illness makes U. urealyticum a significant pathogen?: Upper respi- ratory tract infections in newborns, infections in fetus 146. What factor of Mycoplasma and Ureaplasma makes transport difficult?: - Sensitive to drying and heat
146. How can Mycoplasma and Ureaplasma be identified?: Monoclonal antibod- ies, immunofluorescence, Chen assay
147. What are some general characteristics of Mycobacterium?: Slender rod-shaped organisms, high lipid content in cell walls, acid- fast, nonmotile, strict aerobes, slow growers
148. How does M. tuberculosis infect a person?: Transmitted by airborne droplets, infect the alveoli in the deep lung, bacteria is phagocytized and continues to multiply, forms granulomas
149. What are some symptoms of primary TB?: Nonproductive cough, shortness of breath

Nitrate -, Niacin -

162. What organisms make up the Mycobacterium avium complex?: M. avium and M. intracellulare
163. What is the colony morphology of M. kansasii?: Smooth to rough with wavy edges and dark centers, cross-banding
164. What type of photoreactivity does M. kansasii have?: Photochromogen
165. What biochemical tests can be used to identify M. kansasii?: Catalase +, Nitrate +
166. What Mycobacterium species causes "swimming pool granuloma"?: M. marinum
167. What are the fast growing species of Mycobacterium?: M. fortuitum, M. chelonae, M. abscessus
168. What disease is caused by M. leprae?: Hansen's Disease (Leprosy)
169. What are the 2 forms of leprosy?: Tuberculoid and lepromatous
170. What are some characteristics of leprosy?: Not highly contagious, transmit- ted via direct contact, diagnosed via skin scrapings
171. What laboratory tools are required for the isolation and ID of Mycobac- terium?: Noncirculating ventilation system, biological safety

cabinet

172. How do we test sputum for the presence of Mycobacterium?: Early morn- ing specimen on 3 consecutive days, considered positive if 2 of 3 specimens are positive
173. Why do we digest and decontaminate samples for Mycobacterium?: To remove commensal flora
174. What agents are used to digest and decontaminate Mycobacterium sam- ples?: NaOH -> decontaminating and digesting agent NALC -> liquefying agent
175. What are the steps in an acid-fast stain?: Carbolfuchsin, acid alcohol, meth- ylene blue
176. What culture requirements are needed to grow Mycobacterium?: Strict aerobe, pH 6.5-6.8, humidity
177. What stain is in all egg-based media, and what does it do?: Malachite green, suppresses growth of gram + organisms
178. What are the typical ingredients in egg-based culture medias?: Eggs, salt, glycerol, potato flour
179. What growth rate classifies an organism as a slow grower? Rapid grow- er?: Slow grower -> more than 7 days