WCVD Lloyd lectures

Question 1

What are the three species that comprise the Staphylococcus intermedius group?

Answer 1

S. intermedius, S. pseudintermedius, S. delphini

Question 2

What technique(s) for bacterial identification depends on chromatography and mass spectrometry?

Answer 2

matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS), electrospray-ionization mass spectrometry, Fourier transform infrared spectroscopy, Raman spectroscopy and electrokinetic separation

Question 3

T/F: Sequencing of 16S ribosomal RNA is a useful technique for bacterial identification because the genes are highly conserved.

Answer 3

True - and a large database of specific sequences is available

Question 4

What technique for bacterial identification has been used for defnining the skin microbiome?

Answer 4

16s ribosomal RNA sequencing

Question 5

What coagulase negative staphylococci have been reported to cause infection in dogs, cats, and small mammals?

Answer 5

S. schleiferi schleifer, S. felis, S. lugdunensis

Question 6

What are risk factors for infection with coagulase negative staphylococci?

Answer 6

recent steroid administration, male animals more often affected

Question 7

Characteristics of Macrococcus: Gram + or -? Coagulase + or -? Major species?

Answer 7

Gram positive cocci, coagulase variable (+ or -); M. caseolyticus, M. canis

Question 8

Macrococcus spp. can carry which resistance genes, conferring resistance to all beta-lactam antibiotics, includings those with a beta-lactamase inhibitor?

Answer 8

mecB and mecD –> may be multi-drug resistant

Question 9

T/F: Bacteria of the genus Cutibacterium are commensals of canine skin and there is no report of pathogenicitiy in skin.

Answer 9

True - inhabit hair follicles; single case report of a UTI

Question 10

Bacteria from the genus Trueperella are most commonly associated with what type of infections?

Answer 10

abscesses and bite wounds (cats > dogs), purulent disease in livestock

Question 11

Characteristics of Neisseria: Gram + or -? Common location on body? Major species?

Answer 11

gram negative coccoid bacteria; oral inhabitants of dogs & cats; Neisseria dumasiana, Neisseria canis

Question 12

Characteristics of Burkholderia spp: Gram + or -? Major species?

Answer 12

Gram negative rods; Burkholderia cepacia, Burkholderia pseudomallei

Question 13

This is a ubiquitous, gram negative rod, found in water, moist soil and contaminated environments, and can adhere to plastic. It can cause life-threatening opportunistic infections in immunocompromised humans as well as dogs treated with cyclosporine.

Answer 13

Burkholderia spp. (Burkholderia cepacia & pseudomallei)

Question 14

T/F: Burkholderia cepacia is often multi-drug resistant.

Answer 14

True - culture and sensitivity tests should be carried out to determine treatment options

Question 15

Causative agent of melioidosis in humans and animals (glanders)

Answer 15

Burkholderia pseudomallei

Question 16

Burkholderia pseudomallei is found in water and soil and contaminated environments in what regions of the world?

Answer 16

Southeast Asia, Northern Australia, South Pacific; emerging in Africa and the Americas

Question 17

Burkholderia pseudomallei has been isolated from what animals in the Europe and USA

Answer 17

green iguanas

Question 18

How is Burkholderia pseudomallei typically acquired?

Answer 18

opportunistic infecton in immunocompromised individuals through wounds, inhalation, or ingestion

Question 19

What organism causes the disease Buruli ulcer?

Answer 19

Mycobacterium ulcerans

Question 20

What are the three most common mycobacterial species in human diseases?

Answer 20

Mycobacterium tuberculosis, Mycobacterium leprae, Mycobacterium ulcerans

Question 21

What disease does Mycobacterium ulcerans cause?

Answer 21

Buruli ulcer – results in necrotising ulcers with undermining edges

Question 22

What species of Mycobacterium have been associated with leprosy?

Answer 22

Mycobacterium lepromatosis and leprae

Question 23

T/F: Leprosy is a zoonotic disease.

Answer 23

True - reported to be transmitted from armadillos to humans

Question 24

What two types of bacteria that lack cell walls may be involved in cutaneous infections?

Answer 24

Mycoplasma spp. And L-forms

Question 25

T/F: Mycoplasma spp. are normal members of the oral and upper respiratory tract flora in dogs and cats.

Answer 25

True - have also been found in canine axillary skin in microbiome studies

Question 26

To what antibiotics are Mycoplasma spp. Intrinsically resistant? Why?

Answer 26

beta-lactams and other agents that target the cell wall --> they do not have a cell wall.

Question 27

What are good empirical choices for treatment of Mycoplasma spp.?

Answer 27

macrolides, lincosamides, tetracyclines, fluoroquinolones

Question 28

T/F: Mycoplasma spp. are difficult to isolate in culture.

Answer 28

True - may be readily obscured by other bacteria; need special sampling transport media and special isolation techniques

Question 29

T/F: L-forms lack cell walls.

Answer 29

False - they are partially cell wall deficient, and originate from bacteria with cell walls, they may be able to revert to parental type.

Question 30

Why are L-forms difficult to diagnose?

Answer 30

difficult to demonstrate with light microscopy (require electron microscopy of fresh tissue); cannot be cultured and identified by routine techniques

Question 31

L-forms usually cause infections in what location of the body?

Answer 31

polyarthropathies; cutaneous lesions are typically feline draining abscesses over joints

Question 32

Cytology of infections due to L-form bacteria usually demonstrates what?

Answer 32

non-toxic neutrophils (may contain granules) and macropahges

Question 33

L-form bacteria usually respond to treatment with what antibiotics?

Answer 33

tetracyclines, macrolides, chloramphenicol

Question 34

T/F: Staph aureus MSCRAMMs (microbial surface components recognizing adhesive matrix molecules) are adhesions (lectins) that bind to the extracellular matrix.

Answer 34

TRUE

Question 35

Lectins such as Staph aureus MSCRAMMs (microbial surface components recognizing adhesive matrix molecules) bind via what receptors on host cells?

Answer 35

carbohydrate-recognition domains to glycan receptors on host cells -- either terminal sugar residues or internal sequences found in oligosaccharide chains

Question 36

T/F: Sugars are found in secretions such as saliva and tears that can antagonize the lectin binding sites and prevent colonization of staph aureus.

Answer 36

TRUE

Question 37

What is quorum sensing? What manages quorum sensing?

Answer 37

ability of bacterial species to alter their mode of behavior from a non-aggressive to an aggressive phenotype; involves secretion by the bacteria of peptide signalling molecules which are detected by the other bacteria; managed by the accessory gene regulator (agr) system

Question 38

Is biofilm formation a characteristic of a non-aggressive phenotype or an aggressive phenotype of bacteria?

Answer 38

non-aggressive: bacterial cells are protected fom host attack and other substances (including antimicrobials) by embedding themselves in a polysaccharide matrix formed by capsular material

Question 39

Biofilm formation is promoted by what factors?

Answer 39

stress factors -- including exposure to subinhibitory concentrations of antimicrobials

Question 40

What is secreted by an aggressive phenotype of bacteria?

Answer 40

exotoxins, haemolysins, leucocidins -- provoke more acute disease

Question 41

____ are the most abundant mobile genetic elements of bacteria, which are variable in size and can replicate independently from chromosomal DNA but can integrate into chromosomal DNA.

Answer 41

Plasmids

Question 42

_____ are mobile genetic elements of bacteria that MUST integrate into plasmids or chromosomal DNA to replicate, carrying their genetic material into these structures.

Answer 42

Transposons

Question 43

______ are the smallest mobile genetic elements that usually only carry a single resistance gene.

Answer 43

Gene cassettes

Question 44

These are large mobile genetic elements that have site-specific integration into chromosomal DNA and are typically accompanied by other resistance genes?

Answer 44

Integrative and conjugative elements -- e.g. Staphylococcal Cassette Chromosome mec (SCCmec)

Question 45

Resistance problems have particularly occurred within a small group of pathogens that are commonly associated with nosocomial infections: ESKAPE pathogens. What are they?

Answer 45

Enterococcus faecium, Staph aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterbacter spp., Escherichia coli

Question 46

_____ is resistance to 3 or more antimicrobial classes.

Answer 46

multidrug-resistance (MDR)

Question 47

_____ is resistance to all but one or two classes of antimicrobials.

Answer 47

extensive drug-resistance (XDR)

Question 48

_____ is resistance to all classes of antimicrobials.

Answer 48

pandrug-resistance (PDR)

Question 49

T/F: Classical MRSA infection in dogs and cats is caused by clones that are associated with community-acquired infections.

Answer 49

False - human hospital infections