Gram positive Cocci Flashcards
(117 cards)
1
Q
What are the 2 Staphylococci spp that can grow only anaerobically?
A
1-Staphylococcus saccharolyticus
2-Staphylococcus aureus subsp. anaerobius
2
Q
T/F:
Staphylococcus is catalase +ve
and Streptococci are catalase negative?
A
T
2
Q
What is the bacterial coagulase enzyme that used for coagulase test and what are the 2 types?
A
It is a protein enzyme that enables the conversion of fibrinogen to fibrin.
It binds plasma fibrinogen, causing organisms to agglutinate or plasma to clot.
2 types:
1- bound coagulase
2- Free coagulase
3
Q
All staphylococci are oxidase Negative except 3 spp?
A
S. sciuri group
S. fleuretti
Macrococcus
4
Q
What are the staphylococci spp that are tube coag positive?
A
1-Staphylococcus aureus
2-Staphylococcus argenteus
3-Staphylococcus schweitzeri
4-Staphylococcus intermedius
5-Staphylococcus delphini
6-Staphylococcus hyicus
5
Q
What are the staphylococc spp that are slide coag positive ??
A
1-Staphylococcus aureus
2-Staphylococcus argenteus
3-Staphylococcus schweitzeri
4-Staphylococcus intermedius
5-Staphylococcus lugdunensis
6
Q
What are the 5 staphylococcus spp in staph aureus group?
A
S. aureus subspecies aureus
S. aureus subspecies anaerobius
S argenteus
S schweitzeri
S simiae
7
Q
What are the virulence factors of Staph aureus?
A
1-Adhesins
2-Exoproteins (Exotoxin and enzyme)
3-Biofilm
4-Capsule
5-Small colony variant
8
Q
What are the staphylococcus adhesins ?
A
One major class of adhesin is called the microbial surface component, which recognizes adhesive matrix molecules (MSCRAMMs).
-
Examples are:
1-Staphylococcal protein A (SpA)
2-Fibronectin-binding proteins A and B (FnbpA and FnbpB)
3-Collagen-binding protein
4-Clumping factor (Clf) A and B proteins
9
Q
What are the staphylococcus Exoproteins?
(Enzymes ,Cytotoxic toxins and Exotoxins)
A
1)Enzymes:
nucleases, proteases, lipases, hyaluronidase, and collagenase
——–
2)Cytolytic toxin:
#Hemolysin (α, β, γ)
#Leukocidin
#Panton-Valentine leukocidin (PVL)
———
3)Exotoxins:
#Toxic shock syndrome toxin-1 (TSST-1)
#Staphylococcal enterotoxins:
(SEA, SEB, SECn, SED, SEE, SEG, SEH, and SEI)
#Exfoliative toxins
(ETA and ETB which responsible for Staphylococcus scalded skin syndrome)
10
Q
What are the 2 Staph aureus two superantigens?
A
1-Toxic shock syndrome toxin-1 (TSST-1)
2-Staphylococcal enterotoxins
11
Q
What is a small colony variant (SCV)?
A
They are subpopulation of Staph aureus seen in persistent infection due to mutations in metabolic genes
slow-growing variants
not particularly virulent able to persist and remain viable inside host cells
12
Q
What are the tests that can be done in reference lab in investigating Staphylococcus aureus species?
A
WGS data based on the request:
1-Lineage (Multi Locus Sequence Type – MLST)
2-Cluster address (derived from SNP analysis) - useful in outbreak
3-Detection of resistance genes, including
* mecA and its homologue mecC: resistance to oxacillin
* mupA and mupB :high-level resistance to mupirocin.
4-Toxin gene profiling:
* 9 enterotoxin genes
* 3 exfoliative toxin genes
* Toxic shock syndrome toxin gene 1 (tst)
* Panton-Valentine Leukocidin toxin gene (luk-PV)
13
Q
What are the toxin gene profiling of staphylococcus aureus ?
A
- 9 enterotoxin genes (sea-see and seg-sei)
- 3 exfoliative toxin genes eta, etb and etd
- Toxic shock syndrome toxin gene 1 (tst)
- Panton-Valentine Leukocidin toxin gene (luk-PV)
14
Q
Which staphylococcus species that can grow on MRSA plate?
A
staphylococcus sciuri
because it has mecA gene
15
Q
What is the coagulase test reaction of staphylococcus lugdunensis?
A
Staphylococcus lugdunensis is slide coagulase test positive but tube negative
16
Q
As per EUCAST , how to report SAUR when Benzylpenicillin sensitive, cafoxitin sensitive?
A
report sensitive to all beta-lactams
17
Q
As per EUCAST , how to report SAUR when Bezylpencillin resistant, cefoxitin sensitive?
A
Report resistant to penicillin, amoxicillin, ampicillin (and ticarcillin/piperacillin, but they are not available on their own).
Report sensitive to all other beta-lactams including BLBLIs (coamox, pip-taz).
18
Q
As per EUCAST , how to report SAUR when
A
report resistant to all beta-lactams. These are MRSA.
19
Q
What is the best test to check for staphylococcus penicillinase?
A
Disc diffusion (even better than MIC or chromogenic test like nitrocefin)
20
Q
T/F:
EUCAST recommends only using cefoxitin for screening for MRSA (and not oxacillin)
A
T
as Cefoxitin is better inducer
21
Q
How to interpret penicillin disc diffusion zone size for SAUR?
A
The zone size of penicillin and the zone edge should be checked
-If zone is <26mm, report R.
-If >/=26mm, check the edge.
-If the edge is sharp (cliff) - report resistant.
-If the edge is not sharp (beach), report sensitive.
-If unsure, report resistance.
22
Q
All cephalosporins sensitivity can be inferred from cefoxitin, except …?
A
Which do not have breakpoints and should not be used for staphylococcal infections.
1-Cefixime
2-Ceftazidime
3-Ceftazidime-avibactam
4-Ceftibuten
5-Ceftolozane-tazobactam
===================================
For Cefotaxime & Ceftriaxone - if reporting always use susceptible with increased exposure
23
Q
What cephalosporins that can be S to MRSA?
A
1-Ceftaroline
2-Ceftobiprole
24
T/F
Aztreonam can be used to treat SAUR?
F
Aztreonam has no activity against Staphylococcus
25
How to test and interpret Quinolone susceptibility testing for SAUR??
Screen using norfloxacin
-If norflox S : report moxi S / Cipro SIE / levo S
-If norflox R, test individual quinolones and report accordingly
26
How to test for Amikacin susceptibility for SAUR?
Amikacin should be tested using kanamycin screening
27
T/F:
For SAUR , Glycopeptide MIC should be done using broth microdilution?
T
Resistant isolates should be sent to ref lab
28
How to test dalbavancin MIC for SAUR?
MIC for dalba/oritavancin should be done in the presence of polysorbate-80
However, if an S aureus is vanc sensitive report dalbavancin S.
29
How to test for macrolides Sensitivity to SAUR ?
For macrolide , Use erythromycin as screen, if S, report clarith and azith S. If R test, clari and azithro individually.
30
How to test SAUR for Fosfomycin sensitivity?
Fosfomycin MIC should be tested in the presence of glucose-6- phosphate in the media.
Agar dilution is the preferred method.
31
How to test SAUR for Daptomycin sensitivity?
Should be tested in presence of Ca2+ .
If found R send to ref lab.
32
What are the indication to send SAUR to reference lab based on susceptibility testing ??
1-Any resistance to :
Ceftaroline, ceftobiprole
Vancomycin, teicoplanin, telavancin, dalbavancin, daptomycin
Linezolid & tedizolid
Quinupristin-dalfopristin
Tigecycline
========================
2-Oxacillin MIC 2 – 8 mg/L, cefoxitin MIC >4 mg/L or a discrepancy between oxacillin and cefoxitin
33
What is the gene encode for penicillinase in SAUR?
blaZ gene: Encodes beta-lactamase (penicillinase)
34
What is the blaZ gene in SAUR ?
Encodes beta-lactamase (penicillinase) in SAUR
Hydrolyzes the beta-lactam ring of penicillin
Regulated by blaI (repressor) and blaR1 (sensor/signal transducer)
Carried on plasmids or transposons
Present in >90% of S. aureus isolates
35
What is the gene encode for Methicillin/ Oxacillin Resistance in SAUR?
1-mecA Located on SCCmec (Staphylococcal Cassette Chromosome mec)
2-mecC gene: mecA homolog (~70% identical) Found in livestock-associated MRSA Confers resistance through a similar mechanism
36
what are the risk factors of MRSA infections ?
1-Recent hospitalisation, especially outside the UK
2-Known colonisation with MRSA
3-Recurrent skin and soft tissue infection
4-Not responding to first-line antibiotics
5-Nursing home residents/IVDU/ dialysis/ long-term catheter/Open wounds
37
What is the genetic bases of penicillin resistance in SAUR?
blaZ gene: Encodes beta-lactamase (penicillinase)
Hydrolyses the beta-lactam ring of penicillin
Regulated by blaI (repressor) and blaR1 (sensor/signal transducer)
Carried on plasmids or transposons
Present in >90% of S. aureus isolates today
38
What is the blaZ gene and what are its regulators?
blaZ gene: Encodes beta-lactamase (penicillinase)
Hydrolyses the beta-lactam ring of penicillin
Regulated by blaI (repressor) and blaR1 (sensor/signal transducer)
Carried on plasmids or transposons
Present in >90% of S. aureus isolates today
39
What is the genetic bases of MRSA?
mecA gene:
Encodes PBP2 which has low affinity for beta-lactam
Located on SCCmec
---------------------------------------------------
mecC gene: mecA homolog (~70% identical)
Found in livestock-associated MRSA
similar mechanism to mecA
40
What is the SCCmec location ?
Staphylococcal Cassette Chromosome mec
Mobile genetic elements containing mec genes
13 types identified (I-XIII) with different characteristics
--
Components include:
1-mec gene complex (mecA/C and regulatory genes)
2-ccr gene complex (recombinases for integration/excision)
3-J regions (joining regions with additional resistance genes)
41
What to use for MRSA decolonisation?
1-Chlorhexidine 4% body wash/shampoo once a day for 5 days.
2-Mupirocin (Bactroban Nasal) (use three times a day for 5 days)
------------------
Alternatives:
1-Alternative to chlorhexidine - octenidine.
2-Alternative to mupirocin - octenidine or Naseptin nasal cream
42
What are the EUCAST recommendations for Mupirocin susceptibility testing ?
# MIC : S ≤256, R >256 mg/L
Breakpoints for nasal decolonization in carriers of S. aureus ,:
#Mupirocin MIC S ≤1, R >1 mg/L
#Mupirocin disk diffusion with 200 µg disk S ≥30, R <30 mm
----
For short-term suppression of nasal colonization (usually as a perioperative practice), can use the following breakpoints of mupirocin:
#MIC of ≤256, R >256 mg/L
#Disk diffusion S ≥18 mm, R <18 mm
43
What Abx can be used empirically to treat MRSA ?
Teicoplanin
vancomycin
Daptomycin
linezolid
Maybe tigecycline
----------
N/B: Those need sensitivity tests first - doxycycline, cotrimoxazole, macrolides, chloramphenicol, and clindamycin.
44
What is Vancomycin MIC in VISA & VRSA?
VISA: 2-8 mg/L
VRSA: >8 mg/L
45
What are the chromosomal mutations that lead to structural changes in cell wall in VISA ?
1-Cell wall thickening
#Increased peptidoglycan synthesis
#Reduced peptidoglycan cross-linking
#Creation of more D-Ala-D-Ala sites
-------------------------
2-Altered cell wall metabolism:
#Upregulation of cell wall synthesis
#Mutations in regulatory pathways
#Reduced autolytic activity
--------------
3-Metabolic changes:
#Alterations in teichoic acid structure
#Reduced acetate metabolism
#Changes in membrane potential
---------------
4-Heterogeneous VISA (hVISA):
46
What are the IPC precautions to take in dealing with MRSA ?
1-Contact precautions (gloves, aprons & hand hygiene)
2-Single room
3-Do not transfer patients unnecessarily
4-Consider hydrogen peroxide vapour (HPV) or ultraviolet (UV-C, PX-UV) devices as an adjunct to terminal cleaning
47
What are the regulators of mecA gene of SUAR?
mecI and mecR1: Direct regulators of mecA expression
48
What are the regulators of blaZ gene of SUAR ?
blaI and blaR1:
1-Beta-lactamase regulators that cross-regulate mecA
2- Also : Regulate blaZ gene of SUAR penicillinase blaI (repressor) and blaR1 (sensor/signal transducer)
49
What are the 3 regulatory genes located in the SCCmec region of SUAR?
1-mecI and mecR1: Direct regulators of mecA expression
2-blaI and blaR1: Beta-lactamase regulators that cross-regulate mecA
3-sarA and agr: Global regulators affecting resistance expression
50
What are the genetic components of SCCmec region of SAUR??
Components include:
1-mec gene complex (mecA/C and regulatory genes)
2-ccr gene complex (recombinases for integration/excision)
3-J regions (joining regions with additional resistance genes)
51
What are the BORSA and MODSA?
BORSA:
Borderline oxacillin-resistant S. aureus
Hyperproduction of beta-lactamase
Modifications to existing PBPs
-------------------------------
MODSA:
Modified PBP-mediated oxacillin-resistant S. aureus
Mutations in native PBPs reducing affinity for beta-lactams
52
What is VRSA and what is the genetic mechanism of resistance ?
VRSA (MIC ≥8 mg/L per EUCAST)
acquires high-level resistance through horizontal gene transfer, typically from vancomycin-resistant enterococci:
1-Acquired vanA gene cluster
Usually carried on transposon Tn1546 from enterococci
Often located on a plasmid
2-Modified peptidoglycan synthesis
Production of D-Ala-D-Lac instead of D-Ala-D-Ala
Dramatically reduced affinity for vancomycin (1000-fold decrease)
53
What are screening methods that can be used for VISA and VRSA?
1-Broth microdilution (BMD): Gold standard for MIC determination
2-Gradient diffusion: E-test for vancomycin
3-Agar-based methods: Brain Heart Infusion agar supplemented with 6 mg/L vancomycin
4-Automated systems :VITEK
54
What are Confirmatory methods that can be used for VISA and VRSA?
1-Population analysis profile (PAP) :
#Gold standard for hVISA detection
#Labour-intensive and not routinely available
#Area under the curve (AUC) ratio compared to reference strain (Mu3)
--------
2-Molecular detection :
#PCR for vanA gene cluster (VRSA)
#WGS for mutations associated with VISA
--------
3- Glycopeptide resistance detection (GRD) Etest:
#Specialised Etest for detecting hVISA
#Higher sensitivity than standard vancomycin Etest
55
What are the IPC measures in managing VISA?
Standard contact precautions
Single room isolation
Enhanced environmental cleaning
Consider screening of close contacts in outbreak situations
56
What are the IPC measures in management of VRSA?
1-Strict isolation in a single room with en-suite facilities
2-Dedicated nursing staff
3-Enhanced contact precautions
4-Thorough decontamination of the environment
5-Active screening of close contacts
6-Mandatory notification to Public Health authorities
7-Restriction of patient transfers
57
T/F:
If MRSA and ciprofloxacin sensitive, the chance of this isolate to be a PVL is higher
T
58
What culture media to use in investigating PVL outbreaks?
If potential contacts in a PVL MSSA outbreak:
#A non-selective agar such as blood agar.
---------
For a PVL MRSA outbreak:
#selective medium like Mannitol Salt Agar or chromogenic media for the screening sample.
#Ensure that the selective medium does not utilise ciprofloxacin for MRSA selection
59
What is the Tx of sever sepsis/ SSTI/ Necfac due to PVL-MRSA?
1-Linezolid 600mg bd combined plus: 2-clindamycin 1.2 - 1.8g qds Plus:
3-rifampicin 600mg bd
--------------------
---------------------------------
Surgical debridement
Treat for 10-14 days
IVIG 2g/kg
60
how to treat sever PVL MRSA pneumonia ?
1-Linezolid 600mg bd combined plus: 2-clindamycin 1.2 - 1.8g qds Plus:
3-rifampicin 600mg bd
--------------------
---------------------------------
Surgical debridement
Treat for 10-14 days
IVIG 2g/kg
61
What are the general features that may indicate PVL SUAR as a cause of sever pneumonia?
#Multilobular infiltrates,
#Haemoptysis
#Young
#close contact/patient with recurrent skin infection
#SSTI
#Recent flu-like illness
#Leukopenia
#High inflammatory markers, raised CK (pyomyositis)
62
What oral Abx to use to treat mild SSTI MRSA -PVL infcection in community?
1-#rifampicin 300mg bd PLUS doxycycline (100mg bd – not for children <12 y) or
2-#rifampicin 300mg bd PLUS fusidic acid 500mg tds or
3-#rifampicin 300 mg bd PLUS trimethoprim 200 mg bd or
4-#Clindamycin 450 mg qds
63
What are the IPC Measures to take for PVL positive patient?
1- Isolation single room
2-Use PPE (plastic apron and gloves), 3-Meticulous hand hygiene
4-Environmental cleaning
5-surgical mask with integral eye protectionif suspected necrotising pneumonia during AGP
6-If HCW exposure without appropriate PPE , need to screened 3-7 days post exposur
64
What is the PVL decolonisation?
Bodywash/shampoo once a day for 5 days:
1-Chlorhexidine 4% or:
2-Triclosan 2%
--------------------#
Nasal cream:
Mupirocin (Bactroban Nasal) use three times a day for 5 days
65
Contraindications of PVL Decolonisation?
1-If the patient is non-compliant
2-If there are breaks in the skin
3-neonate.
66
T/F:
Staph lugdeunensis has a characteristic odour (hypochlorite bleach-like smell) similar to Eikenella?
T
67
How to use coagulase test to diffrentiate SAUR from Staph lugdunensis?
1-Both SAUR & Staph lugdunensis Give positive slide coagulase test (bound coagulase)
2- Staph lugdunensis is tube Coagulase Negative (Free coagulase) while SAUR is tube coagulase +ve
68
What are the virulance factors of staph lugdunensis ?
1-Protein biofilm
2-Adherence factors, vWF and fibronectin-binding protein
3-Delta toxins like haemolytic peptide, DNAse, and Lipase.
69
T/F
Staph lugdunensis produce polysaccharide biofilm
F
It produces protein biofilm , unlike other bacteria that produce polysaccharide biofilm
It makes the bacteria highly resistant to antibiotics.
Biofilm formation decreases in the presence of linezolid and tetracycline.
Moxifloxacin is the only abx which is active against biofilm S lugdunensis.
70
Staph lugdunensis and schleiferi have same virulence factors?
Similar virulence factors in satph lugdunensis and staph schleiferi
but S schleiferi, but they mostly cause animal diseases.
71
What are the novobiocin resistant CoNS ?
Staphylococcus saprophyticus
Staphylococcus cohnii
Staphylococcus sciuri
Staphylococcus xylosus
72
What are the virulance factors of Staphylococcus saprophyticus?
1-Adhesins that help it attach to and colonise urothelium.
2-Produce biofilm
3-Produces urease
73
What is the best 2 Abx to treat staph saprophyticus and what is its intrinsic resistance ?
Treatment - nitrofurantoin, trimethoprim.
It is intrinsically resistant to fosfomycin
74
Which staphylococcus spp that is 1ry a dog pathogen and coagulase positive ?
Stah intermedius
75
Coagulase-negative catalase-positive GPC in clusters & exhibits hemolytic activity (β-hemolysis)?
Staph haemolyticus
76
Wat are the commonest antibiotic resistant in staph haemolyticus?
1-High resistance to methicillin (Methicillin-resistant Staphylococcus haemolyticus or MRSH).
2-Multidrug resistance (e.g., to aminoglycosides, glycopeptides, tetracyclines and β-lactams).
77
What are the SSTI that can be caused by GAS?
1-Impetigo;
Involves the superficial skin
yellowish crusts on the face, arms, or legs
Typically caused by Staph aureus or Strept pyogenes.
known as school sores
--------------------------------#
2-Erysipelas
--------------------------------#
3-cellulitis
4-necrotising fasciitis
78
What is Erysipelas?
Mainly caused by GAS.
very sharp, raised border
bright red, firm and swollen.
It may be finely dimpled (like an orange skin)
Bullous erysipelas can be due to GAS plus SAUR co-infection
In infants, it often occurs in the umbilicus or diaper/napkin region.
79
What are the risk factors of IGAS infection ?
1-Aged 75 years or over (care home residents the commonest iGAS in the UK)
2-Immunocompromised or immunosuppressed.
3-Comorbidities :Skin breakdown, diabetes mellitus, cardiovascular disease, or underlying malignancy.
4-Chickenpox with active lesions within 7 days prior to diagnosis of iGAS infection in the index case, or within 48 hours of commencing antibiotics by the iGAS case if exposure is ongoing, or influenza
5-IVDU or are alcohol dependent.
6-Pregnant women.
7-Postpartum women (within 28 days of giving birth).
8-Neonates (aged up to 28 days).
80
What is the main features & complications of Scarlet fever?
1-Commonly affects children between five and 15 years of age.
2- red and blanching rash in the face and chest ( sandpaper rash)
3-LN
4- Strawberry tongue
5- Peeling skin on the fingertips, toes and groin area as the rash fades.
------------------------
Complications:
#Acute rheumatic fever
#Poststreptococcal glomerulonephritis
#Poststreptococcal reactive arthritis
81
What are the Virulence factors of GAS?
1-M protein
2-Protein F - helps in adherence, colonisation
3-lipoteichoic acid
4-hyaluronic acid capsule
5-Extracellular products :
#pyrogenic (erythrogenic) toxin
#streptokinase
#streptodornase (DNase B)
#streptolysins
82
T/F:
GAS is PYR test positive?
# Enterococci
T
PYR +ve (differentiate from other Strep)
Pyrrolidonyl Aminopeptidase
Other positive PYR organisms:
# Some CoNS
#Entrococci
#Some Enterobacteriaceae
83
Which streptococci can be grouped into Lancefield group A ?
Strep pyogenes
Strep dysgalactiae
Strep anginosus
84
T/F
GAS is Bacitracin sensitive
T
Bacitracin S & PYR +ve
85
What is the base of GAS typing?
#Typing of GAS is based upon the determination of the M-protein, which is inferred by sequencing the emm gene
#Emm genotyping is performed by sequencing the 5’-hypervariable region of the emm gene.
#Over 130 emm sequence types have been identified
#Results are reported as an emm sequence type, which usually correlates with the M protein type
86
T/F:
Cotrimoxazole can be used safely to treat GAS ?
F
GAS can collect folate from the environment (like Enterococcus)
So, trim/cotrim may not be effective even if sensitive
87
What is the incubation period for scarlet fever?
2 - 5 days (range 1 - 7 days).
88
T/F:
Acute rheumatic fever is more common after pharyngitis and PSGN after skin infection
T
89
What are the Major Modified jones criteria to diagose ARF?
1-Arthritis
2-Carditis
3-Sydenham chorea
4-Subcutaneous nodule
5-Erythema marginatum
90
What are the Minor modified Jones criteria?
Arthralgia
Fever
Elevated ESR, CRP
Prolonged PR interval
91
What are teh virulence factors of Streptococcus agalactiae?
1-Capsule - polysaccharide layer rich in sialic acid
2-Pilli - for attachment
3-Beta-hemolysin, a pore-forming toxin
4-C5a-ase - inactivates complement C5a
5-Colonisation
92
What is the CAMP test of Streptococcus agalactiae?
GBS is CAMP test positive
It is the synergistic lysis of RBCs by Staphylococcal aureus aemolysin and the extracellular CAMP factor of S. agalactiae
93
What is the granada culture medium and what are the component?
#selective and differential culture medium for GBS
--------------------#
#Crystal violet to suppress Gram positives
----------------#
#colistin to suppress Gram-negatives
-----------------#
#metronidazole to supress anaerobes.
---------------#
#It relies on detecting granadaene, a red polyenic pigment specific to GBS.
94
T/F:
When test for GBS , Benzylpenicillin can be used as a marker for all beta-lactam sensitivity?
F
All but except for pen V (phenoxymethylpenicillin) and flucloxacillin.
Do not use or release these antibiotics for GBS.
95
what agent should be present when test for Dalbavancin MIC?
polysorbate-80.
96
How to treat Neonatal GBS infection?
1-Ideally:
Benzylpenicillin plus gentamicin
------------------
2- Alternative:
#Amoxicillin plus Gentamicin
#3rd gen cephalosporin
#vancomycin
#2nd gen Ceph (cefuroxime) ONLY if not a CNS infection.
97
98
99
What are the 3 spp in strept anginosus group (Previous miliri)?
Strept contellatus
Strept intermedius
Strep anginosus
100
how to diffrentiate Streptococcus anginosus from GAS ?
1-anginosus produces smaller pin-point colonies
2-characteristic caramel-like smell
3- Pyrrolidonyl aminopeptidase (PYR) negative.
101
What are the general features of Anginosus infections?
1- Abscess forming
2-Commensal in oropharynx, GI, and female genital
3-Causes polymicrobial infection - often with anaerobes
4-
102
T/F
Daptomycin is preferred Abx to use in Strep anginosus abscess?
F
Resistance to daptomycin and quinolones (Levofloxacin and Moxifloxacin) develops easily
103
What antibiotics are not preferred to use in Anginosus treatment ?
Tetracycline
sulphonamide
Daptomycin
Quinolones
104
What are the groups of Viridans streptococc?
1-S. mutans group:
S. mutans/ S. sobrinus
--------------------#
2-S. mitis group:
S. mitis /S. infantis/ S. massiliensis/ S. pseudopneumoniae/S. sinensis
------------------#
3-S. salivarius group:
S. salivarius/S. vestibularis/S. thermophilus
-----------------------#
4-S. sanguinis group:
S. sanguinis/S. parasanguinis/S. gordonii
----------------#
5-S. anginosus group:
CIA
--------------#
6-S. bovis group:
S. equinus/S. gallolyticus (S. bovis)/S. infantarius/S. lutetiensis/S. pasteurianus
105
What are the bovis group streptococc?
1-S. equinus
2-S. gallolyticus (S. bovis)
3-S. infantarius
4-S. lutetiensis
5-S. pasteurianus
106
What are the spp in S. salivarius group?
S. salivarius
S. vestibularis
S. thermophilus
107
What spp are in Streptococcus mutans group?
S. mutans
S. sobrinus
108
Which spp are in S sanguinis group?
S. sanguinis
S. parasanguinis
S. gordonii
109
What are the general features of Streptococcus salivarius Group?
1- Commensal in oral cavity
2-low virulence/pportunistic pathogen
3-subacute IE PVE
4- Alfa haemolytic
5-large, mucoid colonies on BA
6-Does not ferment mannitol (unlike S. mutans)
7-Hydrolyzes esculin
8-produces urease !
9-No Lancefield group
110
What is the clinical relevance of S suis?
Zoonotic infection from Pigs
Severe meningitis, septicemia, and IE 20% mortality
----------------#
Lab ID:
1-Alfa haemolytic
2-Small colonies
3-Positive amylase reaction
4-Positive trehalose reactions
5-Can't grow in 6.5% NaCl
6-PYR-negative.
111
How to diffrentiate E ntrococci from S suis?
S suis :
1-Can't grow in 6.5% NaCl
2-It is PYR-negative
112
What are the clinically important neutritionally variant streptococci?
1-Abiotrophia defectivus
2-Granulicatella :
#Granulicatella adiacens
#G. balaenopterae
#G. elegans
113
General features of NVS (Nutritionally variant streptococci)?
#Facultatively anaerobic
#Non-motile / Non-sporing
#Pleomorphic (cocci, coccobacilli, and bacilli)
#Catalase negative
#Oxidase negative
---------------
#Colonies:
1-Very small (0.5 mm)
2-Alpha haemolytic
3-Require pyridoxal (Vit B 6) or cysteine for growth
4-No growth at low or high temp (at 10 or 45°C)
5-Show satellitism with Staph aureus.
114
T/F:
Viridans Streptococcus could be misidentified as Gemella?
T
115
What are the rare infections that can caused by Gemella?
Endocarditis
Septic shock
Arthritis
Meningitis
116
What are the general features of Gemella?
There are 6 Gemella species
Slow-growing
Gram-variable cocci
Facultatively anaerobic
Catalase-negative
Alpha-haemolytic or non-haemolytic
Non-motile/Non-spore-forming Arranged in pairs, tetrads, clusters
