the leading cause of nosocomial bloodstream infections(BSIs)
those with long term(>12days) central venous access
(coagulase-negative staphylococci, S aureus(skin commensals)) microbiologyUWorld HirotoShishido
what makes M tubercucosis acid fast?☆mycolic acids
→retain the carbofuchsin dye and resist decoloration by an acid-alcohol decolorizing agent
→☆isoniazid(inhibit mycolic acid synthesis) makes the bacteria less resistant to decoloration with an acid-alcohol agent microbiologyUWorld HirotoShishido
replication of DNA virusesreplicate within the host cell nucleus utilizing host cell DNA and RNA polymerases
(RNA virus replicate in the cytoplasm except for retrovirus and ☆influenza virus)
poxviruses are unique among DNA virus in that their genome replication occurs completely in the cytosol via use of multiple virally encoded enzymes microbiologyUWorld SIM1UWorld SIM2 HirotoShishido
aspergilloma develops in old lung cavities (from ☆TB, emphysema, sarcoidosis), aspergillus colonizes the cavity, forming a "fungus ball" which appear on CXR as a radiopaque structure that shifts when the patient changes position microbiologyUWorld HirotoShishido
characteristic of Enterohemorrhagic Escherichia coli(EHEC)O157:H7 compared to other species
transmissionEHEC O157:H7 ☆does not ferment sorbitol during overnight incubation, and as a result, sorbitol containing MacConkey agar is used for isolation. And also, it ☆does not produce glucuronidase unlike other species.
point to mefloquineMefloquine is a schizonticide that actively destroys replicating parasites within red blood cells.
However, it is inactivated in the liver and has no efficacy against hepatic schizonts. Therefore, patients must receive mefloquine chemoprophylaxis ☆for 4 weeks upon return to ensure that parasites released from the liver are destroyed when they infect red blood cells (liver schizonts rupture over 8-30 days.) microbiologyUWorld HirotoShishido
cytomegarovirus infection with immunocompetent patientsmononucleosis
immunocompromised patient→ pneumonia in transplant patients, esophagitis, AIDS retinitis
histologically, acute and chronic inflammatory changes, vasculitits, and large ovoid nuclei containing centrized intraeuclear bashophilic inclusions (owl's eye appearance) microbiologyUWorld HirotoShishido
Mycobacterium avium infectionM avium(MAC)
severe cases arise in patients with AIDS
Most patients with disseminated MAC infection have nonspecific symptoms (eg, fever, weight loss, diarrhea).
Widespread involvement of the reticuloendothelial system often causes ☆anemia, ☆hepatosplenomegaly, and/or elevated alkaline phosphatase and lactate dehydrogenase.
Bone marrow biopsy with histopathology typically shows evidence of granulomata composed of ☆foamy epithelioid cells and multinucleated Langhans cells. microbiologyUWorld HirotoShishido
subunit vaccinationHBV
→↑anti-HBs
→☆impair virion entry into hepatocytes
primary central nervous system lymphoma(PCNSL)non Hodgkin lymphoma of ☆B-cell origin that occurs as a late complication of HIV infection
needs to be distinguished from toxoplasmosis via CSF analysis→ positive EBV polymerase chain reaction analysis
+ in toxoplasmosis, ★multiple ring-enhancing lesions are usually present
treatment for recurrence of genital HSVcan be suppressed or minimized with daily ☆valacyclovir(better bioavailability)
suppressive therapy can be offered with multiple yearly episodes of recurrence, it's generally continued for years with periodic re-evaluation
(a short course (7-10days) of treatment with oral acyclovir during primary genital HSV infection usually reduces the duration of viral shedding, time for lesional healing, and local pain; however it does not appear to alter recurrent rates) microbiologyUWorld HirotoShishido
peripheral blood smear seen in the patients with mononucleosis☆reactive(atypical) lymphocytes on peripheral blood smear G —not infected B cells but reactive cytotoxic T cells
(scalloped edge, abundant cytoplasm)
→effecter cells that contain cytotoxic granules composed of ☆perforin and granzymes which are released in response to foreign antigens on the surface of lnfected host cells
(⊕ Monospot test- ☆heterophile antibodies detected by agglutination of sheep or horse RBCs, CMV→negative) microbiologyUWorld HirotoShishido
what environmental organisms cause opportunic infection in the patients with advanced AIDSenvironmental pathogens such as histoplasma(in bird droppings), mycobacterium avium(in water), and cryptococcus(in soil contaminated with bird droppings) often cause opportunistic infection immunologymicrobiology HirotoShishido
especially what organisms are the patient with systemic chemotherapy susceptible to?mucositis(breaches the mucosal barrier)
+neutropenia(neutrophil cannot serve as front line defense against bacterial and fungal pathogens, commensal pathogens from spreading to the bloodstream and deeper tissues)
→most cases of neutropenic fever are due to ☆endogenous commensal organisms
(gram negative enteric bacilli, such as P aeruginosa and gram positive skin organisms such as S aureus, S epidermidis)
dengue fever
symptoms, what condition predispose individuals to more severe infectionflulike febrile illness with marked myalgias & joint pains("break bone fever")
☆retro-orbital pain, rash
1-2% can progress to dengue hemorrhagic fever→ thrombocytopenia, spontaneous bleeding
this affects individuals more frequently in ☆secondary infection with a different viral serotypes microbiologyUWorld HirotoShishido
serum sickness
cause, histopathologytype Ⅲ hypersensitivity
fever, (★)arthritis, itchy rash during the prodromal period of the infection 1-2weeks after antigen exposure
•Antivenom or antitoxin containing animal proteins or serum
•Medications, most frequently antibiotics (e.g., ★penicillin, amoxicillin, cefaclor, trimethoprim-sulfamethoxazole, ☆chimeric monoclonal antibodies→ rituximab, infliximab)
•Infections: ¥Hepatitis B virus
Characteristic of pyrazinamidePyrazinamide is an essential anti-tuberculous drug that is activated into pyrazinoic acid. This conversion is best achieved at an acidic pH, such as that found within host macrophage phagolysosomes.
