What is the preferred treatment option for TB infection?
Click to see answer
INH/Rifapentine x 3 months (3HP) with once weekly DOT.
Click to see question
What is the preferred treatment option for TB infection?
INH/Rifapentine x 3 months (3HP) with once weekly DOT.
What are the two ways bacteria with the AmpC gene can come?
What is the recommended duration for INH treatment in TB patients?
9 months.
What are the side effects of Rifampicin?
Thrombocytopenia within 1-2 weeks; reintroduction is not advisable.
What is the role of factor G in the coagulation cascade?
It is activated by 1,3 ß D glucan in the coagulation cascade of horseshoe crabs.
What are the innate defects associated with disseminated NTM?
Genetic syndromes.
What are some complications associated with scrub typhus?
Encephalitis, seizure, myocarditis, pneumonia, and eschar.
What is the typical treatment for Trichomonas vaginitis?
Metronidazole, 500 mg orally twice daily for one week.
What is the recommended timing for initiating ART in patients with CD4 counts ≥50 cells/mm³?
Within 8 weeks of starting TB treatment.
What are the indications for Telavancin?
SSTI, HAP, VAP.
What should be checked for M. marinum?
Macrolide resistance.
Which species are positive for modified acid-fast stain?
Nocardia, Rhodococcus, Gordonia, Tsukamurella, Dietzia, and some Corynebacterium species.
Which antibiotics are recommended for respiratory pathogens?
Levofloxacin, Delafloxacin, and Moxifloxacin.
What are the first-line choices for MRSA bacteraemia?
Vancomycin, Daptomycin, and Linezolid.
What are the main toxicities associated with aminoglycosides?
Cochleotoxicity, vestibulotoxicity, and nephrotoxicity.
What is the recommended duration for Rifampin treatment?
4 months, daily (10 mg/kg: 600 mg max).
What NTM are associated with disseminated disease in HIV patients?
M. haemophilum and M. kansasii.
What is the treatment for the induction phase of Strongyloides stercoralis?
Ceftriaxone or Penicillin G for 2 - 4 weeks.
What does the mecA gene confer resistance to?
All available β-lactams except ceftaroline.
What radiologic findings are indicative of NTM lung disease?
Nodular or cavitary opacities on CXR or bronchiectasis with multiple small nodules on HRCT.
What is the significance of 1,3 ß D glucan in fungal diagnostics?
It is a polysaccharide present in the cell wall of fungi and indicates invasive fungal infection.
What is the principle for treating active TB in HIV-infected patients?
Follow the same principles as for persons without HIV infection, starting with 4 drugs.
How does Dirofilaria immitis typically present in humans?
As a solitary nodule in the lung.
What are common symptoms associated with bladder instillation of BCG?
Fever and sterile pyuria.
What is Rezafungin and when was it approved?
Rezafungin is a long-acting echinocandin approved in summer 2023, with a half-life of approximately 152 hours.
What is the treatment recommendation for TB/HIV patients on ARVs?
Treat for 6 months.
What is the role of macrolides in treating M. abscessus lung disease?
Their value is questionable, but they may serve as immune modulators.
What should be done if NTM are recovered that are infrequently encountered?
Obtain expert consultation.
What is a black box warning associated with Telavancin?
Nephrotoxicity for CICr ≤ 50 ml/min.
What is the correlation between treatment response and in vitro macrolide MIC for MAC disease?
Treatment success correlates with in vitro macrolide MIC; susceptible ≤ 8 μg/ml, resistant ≥ 32 μg/ml.
What is the initiation phase of therapy for drug-susceptible TB?
INH, Rifampin, EMB, and PZA for 2 months.
What essential feature distinguishes scrub typhus from other endemic diseases?
The presence of an eschar at the site of the chigger bite.
What clinical symptoms are required for diagnosing NTM lung disease?
Pulmonary or systemic symptoms.
What does tetanus produce instead of progressive paralysis?
Severe and painful muscle spasms.
What is a phenotypic marker for the production of ESBLases in GNB?
In vitro resistance of GNB.
What is a potential risk when using Linezolid?
Serotonin syndrome, especially when used with SSRIs or MAO inhibitors.
What are the non-specific clinical features of Babesiosis?
Malaise, fatigue, myalgia, nausea, and fever.
What are the pros of using broad-spectrum antibiotics?
Broad spectrum of activity, large volume of distribution, high oral bioavailability.
What is the incubation period for M. ulcerans or M. genavense?
8 to 12 weeks.
What combination of drugs is used for managing Babesiosis?
Atovaquone + azithromycin OR Clindamycin + quinine.
What is the treatment approach for cavitary MAC disease?
Macrolide (azithromycin preferred), EMB, rifamycin ± injectable (amikacin).
What factors influence the decision to test/treat for NTM?
Likelihood of infection and likelihood of progression.
What is the recommended test for TB infection in individuals ≥ 5 years old with low or moderate risk?
IGRAs (Interferon Gamma Release Assays).
Which antibiotics are considered oral carbapenem-sparing for ESBL producing bacteria causing cystitis?
Fosfomycin, Augmentin, Nitrofurantoin.
What is the loading dose for Anidulafungin?
200 mg loading dose followed by 100 mg daily IV.
What is emphasized in the new guidelines for TB treatment?
Daily dosing over intermittent dosing.
What is the primary difference between cellulitis and erysipelas?
Cellulitis involves deeper dermis and subcutaneous fat, while erysipelas involves the upper dermis and superficial lymphatics.
What is the continuation phase of therapy for drug-susceptible TB?
INH and Rifampin for 4-7 months.
What does Strongyloides larvae migration through the lung cause?
Patchy pulmonary infiltrates or diffuse infiltrate in hyperinfection syndrome.
For what conditions is Rezafungin approved?
Approved for candidemia and invasive candidiasis in patients with limited antifungal options.
What is the contraindication for INH/rifapentine in HIV patients?
Contraindicated in patients on any antiretrovirals except Efavirenz, Raltegravir, or Dolutegravir.
What is the size range of an eschar in scrub typhus?
5 - 20 mm.
What is the significance of a single positive culture from an expectorated sputum specimen?
It is regarded as indeterminate for diagnosis of NTM lung disease.
What is a common side effect of Ceftaroline?
Rash and usual cephalosporin reactions.
What is the classic appearance of Babesia merozoites?
Tetrads with a Maltese cross appearance.
What is the causative agent of Whipple's disease?
Tropheryma whipplei.
What are the advantages of newer generation IGRAs over TST?
They do not cross-react with BCG or NTM and are preferred for BCG vaccinated individuals.
Which Carbapenem is not active against Pseudomonas aeruginosa (PsA)?
Ertapenem.
What is the sensitivity and specificity of T2Candida testing?
Sensitivity: 90-94%, Specificity: >99%.
What is the recommended dosage for Vancomycin?
30-60 mg/kg/d in 2-3 divided doses.
What is the gold standard for the serologic diagnosis of herpes?
Western blot.
Which cephalosporins have a higher risk of causing seizures?
Cefazolin, ceftazidime, and cefepime.
What is the likelihood of tick paralysis in mid-winter for urban dwellers?
Extremely unlikely.
What is the combination used to treat GNB co-producing ESBL and metallo-carbapenemase?
Ceftazidime-avibactam + Aztreonam.
What is the resistance profile of M. bovis?
Resistant to PZA, susceptible to INH, rifampin, and EMB.
How do the borders of cellulitis lesions typically appear?
Indistinct borders that are not raised.
What is the significance of the Carba NP test?
It tests for carbapenemase production.
What is associated with acute kidney injury (AKI) when using Vancomycin?
Trough concentration >15 mg/L.
What are diphtheroid bacilli?
Gram-positive bacilli, club-shaped, non-spore forming, with a palisade arrangement.
What is Fosmanogepix and what does it target?
Fosmanogepix is a prodrug of manogepix that targets inositol acyltransferase (Gwt1) and inhibits protein synthesis.
What is the indication for Tedizolid?
SSTI.
How does Dalbavancin differ in dosing?
It can be given as a single dose or 2 doses a week apart.
What is the indication for Oritavancin?
SSTI, with a one-time dose.
What CNS toxicity can be caused by Metronidazole?
Encephalopathy.
Which age group is preferred for ETV or TAF over TDF?
Patients aged over 60.
Which fungi are exceptions for the presence of 1,3 ß D glucan?
Cryptococcus, mucoraeceous molds, and Blastomyces (yeast phase).
What is the maximum daily dosage of INH for TB treatment?
300 mg (5 mg/kg).
What is hyperammonemia syndrome and its association with lung transplant recipients?
A rare but sometimes fatal complication linked to Ureaplasma spp and M. hominis pulmonary infection.
What is a potential side effect of metronidazole?
Metronidazole-induced encephalopathy.
Which antibiotics are used for treating macrolide-resistant MAC?
Rifabutin, Ethambutol, and Linezolid.
What is the significance of GATA2 deficiency?
It is associated with cytopenia and can lead to disseminated NTM.
What tests confirm susceptibility to oxacillin in serious infections?
PBP2a testing or NAAT to detect mecA and mecC.
Which antibiotic can lead to optic neuropathy?
Ethambutol.
What is the prophylaxis recommendation for adults with AIDS and CD4 < 50?
Azithromycin 1200 mg/week or clarithromycin 500 mg BID.
What type of antifungal is Ibrexafungerp and what does it inhibit?
Ibrexafungerp is a triterpenoid antifungal that inhibits glucan synthase to prevent fungal cell wall formation.
What is a common mechanism of antibacterial resistance?
Enzymatic inactivation.
What is the mechanism of macrolide resistance?
Selection of isolates with mutations inhibiting macrolide ribosomal binding (erm gene).
Which generation of cephalosporins has antipseudomonal activity?
4th generation (Ceftazidime and Cefepime).
What should be monitored in immunocompetent patients with Babesiosis?
Parasitemia using peripheral blood smears.
What is the duration of therapy for severe or previously treated MAC disease?
12 months of sputum culture negativity while on therapy.
What is a must-know tick-borne infection?
Ehrlichiosis, Anaplasmosis, Rickettsiosis, Q fever.
What diagnostic method is used for T2Candida?
Magnetic resonance-based diagnostic using nanoparticle technology.
What are the first-line echinocandins for treating Candida infections?
Anidulafungin, Caspofungin, Micafungin, and Rezafungin.
Which antibiotics are associated with ototoxicity?
Vancomycin, macrolides, and minocycline.
What is strongly recommended for TB treatment?
Directly observed therapy.
What are the microbiologic criteria for diagnosing NTM pulmonary disease?
At least one positive culture from 2 separate sputum samples, one bronchial wash, or a biopsy with mycobacterial features.
What type of paralysis is associated with Guillain-Barré syndrome?
Ascending paralytic disease.
What is the recommended treatment for M. abscessus lung disease?
Amikacin, Tigecycline, and Linezolid.
What caution should be taken when initiating ART in patients with tuberculous meningitis?
High rates of adverse events and deaths have been reported.
What type of antibiotic is Telavancin?
A vancomycin derivative.
What has been the trend in wound botulism cases in the United States?
Dramatic increase, often associated with injection drug users.
What are the implications of immune reconstitution syndromes?
They can lead to lymphadenitis and granulomatous hepatitis.
What are the two forms of Strongyloides stercoralis larvae?
Rhabditiform (in stool) and filariform.
What factors influence the diagnostic evaluation of NTM?
The virulence of the isolated NTM, the host's immune status, and the clinical source of the organism.
What are the major families of Carbapenemases?
Non-metallo (serine at active site), Metallo (Zinc at active site), OXA (oxacillinase).
Which class of Carbapenemases does KPC belong to?
Class A.
What neuroimaging findings are associated with CNS Whipple's disease?
MRI T2 hyperintense patches with variable contrast enhancement.
What is 'hot tub' lung usually associated with?
MACs (Mycobacterium avium complex).
What is a positive epidemiological risk factor for disseminated NTM?
Travel history related to dimorphic fungi (histoblastococci).
What are the primary diagnostic methods for Candida spp. infections?
Blood cultures, antigen assays, and antibody assays.
When are IGRAs considered better tests?
When TST administration is suspect, in BCG vaccinated populations, and in populations with a poor rate of return.
What are some acquired defects that can lead to disseminated NTM?
Immunodeficiencies or autoimmunity.
What are the criteria for a positive diagnosis of NTM?
Positive culture from a BAL or bronch wash, or positive culture from a lung biopsy with consistent histopathology.
What type of bacteria most commonly causes cellulitis?
β-haemolytic streptococci, sometimes S. aureus.
What does the eschar represent in scrub typhus?
Tissue reaction at the chigger bite site and local proliferation of O. Tsutsugamushi.
What is the typical cause of botulism in adults?
Ingestion of preformed toxin in contaminated food or infection of a wound with Clostridium botulinum.
What is the characteristic appearance of erysipelas lesions?
Brightly red, indurated, well-demarcated.
What are the risk factors for CMV antiviral resistance?
Prolonged drug exposure and being a lung transplant recipient.
What are common pathogens in intravascular catheter-related infections?
Coagulase-negative staphylococcus, Staphylococcus aureus, and Corynebacterium jeikeium.
What is a preventive measure for nephrotoxicity when using antibiotics?
Adequate hydration.
What are the common mechanisms of antibiotic resistance in Acinetobacter?
Efflux, porins, inactivation, target site alteration, and bypass of target.
What is avibactam?
A new β-lactamase inhibitor with activity against ampC.
What type of bacteria does 6th generation cephalosporins target?
ESBL producing GNBs and has antipseudomonal activity.
What is the activity of 8th generation cephalosporins?
Effective against serine/metallo carbapenemase producing Enterobacterales and non-fermenters, but not useful against Gram-positive and anaerobic bacteria.
What is neuroretinitis and its common cause?
Acute visual loss from optic nerve edema associated with macular edema, commonly caused by Bartonella henselae.
What is the recommended approach for managing a fungal infection?
Remove focus of infection, decrease immunosuppression, restore immune function, and begin antifungal therapy early.
What is the primary concern regarding treatment for NTM lung disease?
The decision to treat is based on a risk/benefit analysis.
What factors influence the decision to treat NTM lung disease?
Diagnosis confidence, radiographic extent, and whether the disease is cavitary.
What are common chronic lung diseases associated with NTM infections?
Bronchiectasis, Cystic Fibrosis, and Chronic Obstructive Lung Disease.
What is a common site of disease for NTM?
Bone.
What is the maintenance phase treatment for Strongyloides stercoralis?
Septrin (treatment dose) for 1 year.
Which β-lactam antibiotic has no activity against Gram-positive bacteria?
Aztreonam.
What are the characteristic skin lesions of M. leprae?
Scaly skin lesions that are hyper- or hypopigmented.
What is the most common Babesia species diagnosed in the United States?
B. microti.
What is the risk of using aminoglycosides in myasthenia gravis (MG)?
They should be avoided due to neuromuscular effects.
What laboratory techniques are used for diagnosing scrub typhus from an eschar?
Immunohistochemistry (IHC) and nested DNA PCR assay.
What organisms can cause infections from tattooing using contaminated water?
M. fortuitum, M. chelonae, M. abscessus.
How does ceftazidime compare to other β-lactams regarding ampC induction?
Ceftazidime induces ampC less than other β-lactams.
What is the effect of imipenem-relebactam on ampC?
Relebactam inhibits ampC and is poorly effluxed.
What is the natural reservoir for scrub typhus?
Rodents, maintained by transovarian transmission of Trombicula mites.
When can treatment be discontinued for patients with CD4 counts?
Once CD4 >100 for more than 3 months.
What are the risk factors associated with M. bovis?
Unpasteurized milk products, travel, gifts from foreign places.
When should ART be initiated in patients with CD4 counts <50 cells/mm³?
As soon as possible, but within 2 weeks of starting TB treatment.
What is a significant side effect of Telavancin?
Bone marrow suppression.
What causes peripheral neuropathy in certain antibiotics?
Inhibition of protein synthesis and nerve tissue injury.
What should be monitored when using Daptomycin?
Therapeutic drug monitoring due to potential emergence of resistance.
What is the dosing schedule for Rezafungin?
Once weekly dosing.
What is the significance of the erm gene in M. fortuitum?
It confers inducible macrolide resistance.
What organisms are associated with nail infections in patients frequenting nail salons?
M. fortuitum.
Which NTM species are known to be frequent contaminants?
M. gordonae, M. terrae complex, M. mucogenicum.
What are the cons of broad-spectrum antibiotics?
Increased resistance, serious adverse effects (C. diff), many drug-drug interactions.
Which antibiotics are considered less nephrotoxic alternatives?
Cefoperazone, ceftriaxone, clindamycin, macrolides, doxycycline, minocycline, ciprofloxacin.
What is a significant concern regarding antibiotic resistance in Corynebacterium?
Daptomycin resistance can develop during treatment due to the pgsA2 gene.
What is the activity of Ceftazidime-avibactam against OXA-48?
Active (Avibactam binds OXA-48).
What causes scrub typhus?
Orientia tsutsugamushi, an obligate intracellular gram-negative coccobacillus.
When should echinocandins be recommended as first-line treatment?
If there is prior azole exposure or infection due to C. glabrata, C. krusei, or C. auris.
What is the mechanism of methicillin resistance in Staphylococcus aureus?
Mediated by the mecA gene, which alters the PBP target to PBP2a.
Which antibiotic is associated with idiopathic intracranial hypertension?
Tetracycline, especially doxycycline.
Which drug is recommended for treating M. kansasii?
Rifampin-based regimen.
How often should CSF PCR be repeated to evaluate treatment response?
Every 2 - 3 months until negative.
What is the typical appearance of an eschar in scrub typhus?
A brownish-black crusted necrotic ulcer with an erythematous halo, resembling a 'cigarette burn'.
What new drug is used for MDR TB?
Bedaquiline.
What prophylaxis is recommended for Burkholderia pseudomallei?
Septrin/Doxycycline/Augmentin.
How is Babesiosis diagnosed?
By intraerythrocytic ring forms on peripheral blood smear examination.
What is the activity spectrum of 1st generation cephalosporins?
Effective against MSSA, E. coli, and Klebsiella sp., but no activity against enterococci.
What is the significance of a 5 mm tuberculin skin test result?
It is positive in high-risk individuals.
What are the clinical presentations of classical Whipple's disease?
Arthralgia, weight loss, abdominal pain, and diarrhea.
What are preferred oral agents for MSSA bacteremia?
Linezolid, Septrin, FQ + rifampin, clindamycin.
What typically causes infectious diarrheal disease to last more than 2 weeks?
Giardia, Cyclospora, Amoeba, or Cryptosporidium.
Which antibiotics are used for aerobic Gram-negative bacteria (GNB)?
Ciprofloxacin.
How is M. leprae diagnosed?
By pathology showing invasion of nerve cells by AFB or foamy macrophages.
What are the three mechanisms of nephrotoxicity associated with Vancomycin?
Immune mediated (AIN), mitochondrial inhibition and oxidative damage (ATN), cast formation (ATN).
What are common infections associated with non-diphtheriae Corynebacterium?
Pneumonia, CRBSI, endocarditis, implant-associated infections, wound infections, and UTIs.
What is the treatment approach for infections caused by lipophilic Corynebacterium?
Combination of antibiotics, steroids, drainage, and surgery, with susceptibility testing for lipophilic antibiotics.
What is a common complication in managing infections caused by Corynebacterium?
Recurrent episodes often requiring multiple image-guided drainage or incisional drainage.
What recent advances have been made in anti-Pseudomonas antibiotics?
Ceftolozane-tazobactam and cefiderocol, designed to penetrate the outer membrane and resist hydrolysis.
What factors should be considered when diagnosing infections caused by Corynebacterium?
Patient/clinical and microbiological factors, along with additional microbiological investigations.
What is the risk associated with Meropenem and Ceftolozane/tazobactam?
Risk of inducible AmpC production.
What is the treatment regimen for multibacillary forms of M. leprae?
Dapsone daily, rifampin monthly, clofazimine daily.
What is the treatment approach for uncomplicated Staphylococcus aureus infections?
Systemic antibiotics.
What is the suggested treatment approach for moderate to severe CRAB infections according to IDSA guidelines 2022?
Combination therapy with at least 2 agents with in vitro activity is suggested.
What is a common cause of hepatotoxicity associated with antibiotics?
Drug-drug interactions.
Which antibiotics are associated with DRESS syndrome?
Anti-TB antibiotics, glycopeptides (vancomycin, teicoplanin), and sulphonamides.
How long does cryptosporidiosis typically last in healthy individuals?
1 to 2 weeks, but can sometimes last several weeks.
What is the sensitivity and specificity of IHC on the eschar for diagnosing scrub typhus?
100% sensitivity and specificity.
What is the recommended therapy for nodular/bronchiectatic MAC disease?
Macrolide/EMB/rifamycin intermittently (3x/week).
What is the activity of 5th generation cephalosporins?
Similar to ceftriaxone with MRSA activity, but no activity against enterococci.
What is the recommendation for testing after symptoms have resolved in immunocompetent patients?
Recommend against testing once symptoms have resolved.
What is the drug of choice for MAC lung disease?
Amikacin.
What are common signs and symptoms of scrub typhus?
Fever, chills, headache, generalized lymphadenopathy, and eschar at the bite site.
What is the sensitivity of CSF PCR for diagnosing CNS Whipple's disease?
80 - 92%.
What is the incubation period for scrub typhus?
6 to 21 days.
What are the most prevalent Nontuberculous Mycobacteria (NTM) causing pulmonary disease?
MAC, M. kansasii, M. abscessus (in order of prevalence).
Which NTM is commonly associated with lymph node disease?
MAC and M. scrofulaceum.
