Infectious Disease Flashcards by Matthew Steele

Which methodology is considered to be most sensitive for detecting cytoisospora in cats?

PCR, the other method is faecal flotation.

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What percentage of dogs with Trypanosoma cruzi infection will have ECG abnormalities?

95% - with ventricular arrhythmia (65%) and AVB being most common

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What echocardiographic abnormalities are common in dogs with Trypanosoma Cruz?

RV or LA enlargement

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What factors are associated with increased risk of cardiac death in dogs with Trypanosoma Cruz infection?

RV enlargement
Higher bodyweight
+/- modified Lown score > or = 2

https://paperpile.com/app/p/6824a4e1-2932-0775-bec9-889a9064bcff

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Which of the following is true regarding measureement of serum and urine antigen concentrations in the treatment of feline histoplasmosis?

a) Both tests were sensitive but not specific for detection of disease remission

b) Both tests were specific but not sensitive for detection of remission

Also note that urine was positive for antigen in more cases at diagnosis than serum was.

https://paperpile.com/app/p/65b2a280-ad0c-0a26-bf7f-a4a8815d53bc

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Prevalence of subclinical bacteria in older cats?

10 - 13%, being female increased the risk

https://paperpile.com/app/p/9b6f555b-6171-02ac-ac8c-3ca80a4dc5a6

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Based on testing by Nichols et. al 2017, what may be said of POC ELISA and PCR testing for diagnosis of FIV?

Generally there was good agreement between tests although there was 6% of results that were discordant.

Only one PCR result was a false negative and there was a low rate of false positives for both tests.

https://paperpile.com/app/p/21a6d59a-97d4-05ca-bf04-db0537de1cfe

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What is the most common haematologic abnormality in dogs with leptospirosis?

a. Thrmobocytopenia
b. Hyperfibrinogenaemia
c. Hypercoaguable state
d. Hypocoaguable state

The most common was acutally anaemia, dogs with hypercoaguable states had better survival than those with hypocoaguable states. Interestingly, DIC was not a prognostic factor.

https://paperpile.com/app/p/facb2d28-4eaa-08d0-8709-207b4eeea666

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What is the most likely bacteria when cocci are identified on skin cytology of a dog?

Staphylococcus pseudintermedius

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Give examples of antibiotics that have concentration dependent killing and what are their doses based on?

Aminoglycosides - should have a Cmax:MIC >8 - 10x

Fluroquinolones- should have an AUC24:MIC >100-125x

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What is the ‘post-antibiotic effect’?

The ability of antibiotics to kill bacteria beyond the time/concentration at which they are above MIC

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How long should time be greater than MIC as a general rule for time dependent antibiotics?

40 - 50%

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How should time vs. concentration dependent antibiotic dosing be adjusted in renal failure?

Conc = decrease dose

Time = increasing dosing interval

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Why are enterococcal species inherently resistant to cephalosporins?

They lack PBPs

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Meaning of ESBL

Ability to hydrolyse penicillins, 1st generation cephalosporins AS WELL AS extended spectrum cephalosporins.

ESBL has only been described in E. coli and Klebsiella with CTX-M beta-lactamases being the most important at conveying ESBL resistance

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Which genetic modification allows evasion of beta-lactam antibiotics by staphylococci

MecA

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Which retroviral drug (other than GS…) has shown to have efficacy in feline retroviral infections?

Zidovudine

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Mechanism of action of acyclovir drugs

Both are guanosine analogues that are activated by viral thymidine kinase into monophosphate forms which is then subsequently phosphorylated by host machinery into monophosphate forms.

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Which anti-viral drugs have been shown to have efficacy in feline herpesviral infections?

Famciclovir (penciclovir) = may be administered orally.
Acyclovir (Valacyclovir) = topical only
Lysine (amino acid) = effective orally for conjunctivitis but NO EFFECT OR MAY WORSEN URT FHV
Cidofovir = topical, nasolacrimal irritation/stenosis reported in humans and rabbits

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Which anti-viral has been used in canine parvovirus infections?

Oseltamivir (Tamiflu)

Can’t find the paper that documents this from JVIM or JAVMA but a JVECCS article showed they had better WBC count and gained weight compared to controls. Although no survival benefit was demonstrated.

https://pubmed.ncbi.nlm.nih.gov/20230441/

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What immunomodulatory dry has been used in grey collies with cyclic neutropenia? What is the disadvantage of this drug?

Filgrastim

Not great for long term use as antibodies will develop to it within 2 - 3 weeks

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What are the potential indications for feline interferon omega?

FIP = no good in clinical trials

FCV = stomatitis improves with administration
FIV/FeLV = may improve clinical scores and some laboratory parameters
FPLV = no effect
CPV = may reduce disease severity and reduce mortality

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MoA of penicillins

Binding to penicillin binding proteins inhibits transpeptidation of the peptidoglycan layer of the cell wall. Meanwhile, cell wall hydrolysis continues and cell wall breakdown will occur.

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Penicillin binding types and effect when bound

PBP 1a & 1b inhibition leads to cell lysis
PBP2 leads to change in cell shape but not necessarily bacterial death

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Which penicillins have poor bioavailability?

Penicillin G Ampicillin

What is the mechanism by which bacteria become methicillin resistant?

PBPs switch to PBP2a, this conveys resistance to all beta-lactams

Which cephalosporin has activity against methicillin resistant staphylococci?

Ceftaroline - as it has affinity for PBP2a

Which antibiotics can cause a false positive on a glucose test strip?

Cephalosporins and fluroquinolones

Which antibiotics antagonise vitamin K reductase?

Cefoteta and ceftriaxone

Weird side effect of ceftiofur, cefonicid and cefazedone

Bone marrow suppression

True or false: bacteria with methicillin resistance are susceptible to carbapenems

False

If you have a Klebsiella pneumoniae resistant to crabapenems, what other antibiotic classes will you expect resistance to?

Beta lactase Aminoglycosides Fluroquinolones

What is the role of cilastatin in antimicrobial drug prescribing?

Imipenam can cause nephrotoxicity through its degradation by dehydopeptidase-1, which is inhibited by cilastatin

Mechanism of action of vancomycin

Vancomycin is a glycopeptide that binds to D-ananyl-D-alanine preventing addition of further cell wall sub units.

What are the clinical indications for vancomycin use?

Note that it is not absorbed orally. MRSA/MRSP Enterococcal infections (VRE can occur here) Corynebacterium urealyticum Clostridium difficile

What antimicrobial has been associated with 'red-man syndrome'?

Vancomycin

Relasionship between fluoroquinolone targets of action and type of bacteria affected

Toipoimerase II (DNA gyrase) is the target of most earlier generation fluroquinolones and is the main target for gram NEGATIVE organisms. Toipoimerase IV inhibition can occur with newer drugs (e.g. pradofloxacin) and is the main target for gram POSITIVE bacteria

Which fluroquinolones have greater activity against pseudomonas than the others?

Ciprofloxacin and pradofloxacin

What types of medications may interfere with fluoroquinolone absorption?

Cation containing medications e.g. antacids or aluminium, calcium, iron and zinc

What are the main bacterial targets of metronidazole?

Bacteroides fragilis Clostridium

Mechanism of action of MTZ

Nitro group of MTZ accepts electrons from electron transport proteins in preference to the bacterial electron transport chain and this then generates short lived intros free radicals

Mechanism of MTZ anti-oxidant effect

Scavenging of ROS, intracellular concentration that may then modulate neutrophil function.

Site of metabolism of metronidazole

Liver

What is the relationship between type of POC test for FeLV and FIV and diagnostic performance?

- SNAP had a S&S for FeLV of 100%, witness was next besed followed by Antigen and Vetscan. - No difference for FIV in test performance https://paperpile.com/app/p/c1dc89d5-60f4-0ad7-9a2a-ccdbe7d983ae

When could PCR testing of dogs that have been treated for 10 days with atovaqoune and azithromycin for B. gibsonii be performed without impacting treatment efficacy?

30 days. This was successful in 93% of fighting dogs. https://paperpile.com/app/p/58e92974-6206-0cb5-902d-a51847b87c8c

Number of dogs that develop oppertunistic invasive fungal infections wen treated with ciclosporin and risk factors for development.

13%, male dogs more likely. https://paperpile.com/app/p/6b114ede-9805-0844-946b-c567c16002bd

What antimicrobial, other than doxycycline, has been shown to have efficacy in the treatment of E.canis recently, and how does it compare to doxy?

Minocycline. Dogs tested negative a bit later on (28 days) in the minocycline group compared with the doxycyclien group (3 weeks)

Which Bartonella spp. are North American dogs most likely to be seroposiive to?

B. henselae and B. kohlerae

What sigalment characteristics are associated with Bartonella seropositivity in north american dogs?

Being ME compared to being female Being mixed-breed

Sensitivity and specificity of POC PCR assay for Babesia

90% and 99% for B. gibsoni 87% and 98% for Babesia spp.

What is the effect of FMT in dgs with parvoviral enteritis, which strain of CPV has this been shown in?

Faster resolution of diarrhoea and shortened hospitalisation times (but not survival times) CPV-2b

What are the risk factors for deveopment of intravenous catheter bacterial complication?

Being a junior member of staff, student or the patient being administered steroids

What is the most common bacteria isolated from IV catheters?

Acinetobacter

What is the maximum size of cribriform plate lysis from aspergillosis that may still be treated with topical therapy without over concern for complications

16x22mm2

What percentage of dogs that have previously been negative on Bartnoella IFA may be additionaly identified using an expanded IFA panel?

15%

Percentage of cytbM128 mutation in Babesia gibsoni infections?

3.5%

Which infectious organisms are dogs that have T. cruzi most likely to also be seroreactive to?

Dirofilaria

What is the most seroprevalent Ehrlichia spp. in the USa and what are the most common presenting signs?

E. ewingi Renal, IMHA, proteinuria, joint pain

How many organisms were reported to develop carbapenem resistance after initially being sensitive?

What associations between B. canis and serum lipids have been noted?

B canis has lower serum cholesterol, phospholidids and alpha-lipoproteins but higher ApoA-1 concentrations SAA was correlated with HDL width and ApoA-1 concentrations

What environmental factor may predispose dogs to T. cruzi?

Having and infected litter or housemate

Which Babesia sp. are more likely to be coinfected?

B. gibsoni and B vulpes

What breeds seem to be overrepresented with B. vulpes infection?

Fighting dog breeds e.g. american bull terrier

Which of the following POC cryptococcus antigen tests is more sensitive? - CrAg LFA - Crypto p5

Cr AG with a sensitivity of 92% and specificity 93.2%

Which Bartonella spp. has been associated with co-infection of Rickettsia rickettsii?

B. vinsonii subspp. berkhoffi

Which biochemical parameter is noted to be prognostic in cats with FPLV infection?

TT4

What reduction in bacterial infection frequency is expected following tracheal stent placement?

52%

What factors make bacterial culture less likely or reduced compared to more likely in dogs that have tracheal stent placement?

Less: young age with congenital malformations More: history of pneumonia or cardiac disease in older dogs, hepatomegaly in younger dogs

% of cats that test positive for Tritrichomonas on PCR following an initial treatment with Ronidazole

21%

What percentage of dogs with proteinuria in the SE USA were seropositive to a VBD and which were the most common spp.?

34% Rickettsia 19%, Ehrlichia 12% and B. burdongoferi 9%

Does immunosupression predispose dogs that have previously had E. canis treatment to recrudescence of infection? For which immunosupresive agents has this been demonstrated?

No, this has been shown for prednisolone or ciclosporing treated dogs that have previously had 4 weeks of doxycycline +/- imidocarb

What disease process has Bartonella rochalimae been associated with?

Infectious endocarditis

What was the reduction in risk and OR for developing leptospirosis related AKI in dogs following introduction of an L4 vaccine?

Reduction in AKI-L from 56.5 to 15.7 cases/year OR of 0.11 for L4 vacc. compared to 2.08 for dogs with L2

how long after experiemental infection of cats with Cytoisospora felis will oocysts likely not be detected in the faeces

15 days

Which bacterial class are rapidly growing mycoplasma spp. likely to be resistant to compared with M. avium?

Rapidly growing = 3rd/4th generation cephalosporings M. avium = fluroquinolones

What histoplasma antigen is detected in feline urine?

Galactomannan

What blastomyces antigen concentration and radiographic lung severity score is associated with better survival in dogs with blastomyces?

BACU <5ng/mL and RLS 1 - 2

Which genetic mutation of cytauzoon felis has been noted to be associated with development of resistance to standard treatment with atovaqoune and azithromycin?

Cytb M128

What is the most common presenting sign for dogs with Heterobilharzia americana?

Diarrhoea

What infectious organism should be suspected in a dog with primary gastrointestinal signs, abscence of hypercalcaemia and pinpoint hyperechoic foci noted in intestines, liver and mesenteric lymph nodes in a dog?

Heterobilharzia americana

Which marker of endothelial activation has been shown to predict the development of leptospiralpulmonary haemorrhage syndrome?

slCMN-1

What is the percentage of dogs alive 1 year after diagnosis of intracranial coccidiomycosis

82%

What breed has Rasamonsia argillacea been documented in and what are the presenting sings?

GSD Presenting signs of anorexia and back pain were most common

What treatment may be employed in dogs with coccisdiomycosis which have become refractory to treatment with fluconazole or itraconazole?

Posaconazole

What percentage of cats treated with famciclovir TID for FHV-1 signs showed improvement and what dose may be best?

51% had marked clinical improvement, 34% mild improvement and 15% no improvement. 90mg/kg TID was better than 40mg/kg TID

What cats are more likely to get Alaria infection and what seems to be the natural reservoir?

Feral cats Mesocercaria have been identified from wild pigs and a single opossum

What percentage of dogs in ICU may be seropositive to CDV and CPV respectively?

CDV - 50% CPV - 80%

What is the percentage of dogs that survive who are diagnosed with parvovirus but managed on an outpatient basis?

75% survived for ≥3 days

Which types of dogs are more likely to have systemic cuterebra infection and in which species is mortality rate higher?

≤4.5kg and YRT Dogs had a mortality rate of 30% and cats 4.5% Interestingly no cats had DIC but 40% dogs did

Which breeds are more likely to have disseminated histoplasmosis and which are more likely to have GI signs only?

Working and herding breeds seem overrepresented in disseminated disease whereas toy breeds are more likely just to have GI signs. N.B Diarrhoea is a positive prognostic indicator.

Is oral milbemycin oxime and spinosad good for Dirofilaria treatment?

No, essentially it does not kill Mf

Which of the following treatments may be associated with non-survival in cats with FPV? - Amoxicillin - Antiparasitics - Glucose - IVFT

Glucose

What drug combination may be beneficial in the treatment of trypanosomiasis?

Amiodarone and itraconazole

What infectious agents have been detected in cardiac tissue of dogs with unexplained myocardial or rythm disorders?

CDV, coronavirus, CPV 2 and Bartonella spp.

What disease should be suspected for a dog presenting following exposure to wild rodents and lymphadenopathy?

Francisella tularensis

What is the predominant bacterium found in culture of brachycephalic middle ear effusions?

Staphylococcus pseudintermedius

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Infectious Disease Flashcards

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