2. Capnocytophaga :
– Capnocytophaga were first described in 1956 by Prevot at the Pasteur institute in Paris.
– These bacilli had been isolated from the human oropharynx and clinical specimens and were given
the name CDC group DF-1. DF was an abbreviation for “dysgonicfermenter,” referring to the poor
fermentative capabilities of these organisms in medium not supplemented with serum
– These organisms were named Capnocytophaga species, reflecting their “consumption” or requirement
for CO2 for growth
– The type species was named Capnocytophaga ochracea, and related isolates from the human
oropharynx were named Capnocytophaga sputigena and Capnocytophaga gingivalis
Capnocytophaga belongs to the family flavobaceriacae
3. – CDC group DF-2 was originally isolated in 1976 from blood and spinal
fluid cultures of a patient who had become symptomatic after suffering a dog bite
– DF-2 was subsequently named Capnocytophaga canimorsus (Latin for “dog bite”), and
the “DF-2-like” strains were called Capnocytophaga cynodegmi (Greek for “dog bite”) based on
phenotypic characteristics and DNA relatedness studies.
– They are similar with respect to Gram’s stain morphology, cellular fatty acid composition, gliding-type
motility, and cultural conditions for growth, but different phenotypically.
In 2000, C. granulosa was isolated from an abscess in an immunocompetent patient
– In 1994, Capnocytophaga granulosa and Capnocytophaga haemolytica were identified in human
dental plaque specimens, and, in 2008, Capnocytophaga leadbetteri and Capnocytophaga
genospecies AHN8471—were described among 62 oral isolates from children
4. Clinical isolates of capnocytophaga spp found in the human oral cavity :
classification
1. C. gingivalis
2. C. granulosa
3. C. haemolytica
4. C. leadbetteri
5. C. ochracea
6. C. sputigena
Those species that colonize the oral cavities of dogs ( and occasionally cats ) :
1. C. canimorsus
2. C. cynodegmi
Some species remains unclassified according to sequence analysis of 16S rRNA gene,
as AHN9607/AHN9576/AHN9798/AHN8471/ChDC.
5. Characteristics :
Gram-negative bacilli
Facultative anaerobic
Flexible
Spindle form ( fusiform)
Gliding motility
Fermentative metabolism
Capnophilic
Cells size : 0.42-0.6 µm × 2.5-2.7 µm
• Shaped like bent rods or filaments, usually with rounded or slightly pointed ends
In liquid culture; polymorphic, or take on a long , filamentous morphology, and tight clumps
No capsule, no sheath, no spores, no flagella
slow-growing
Colonies visible after 48 hrs
Colonies of the organism are yellow, tan, or slightly pinkish and have marginal finger-like projections
(gliding motility) appearing as a film surrounding the central area of the colony
The central part of the colonies also has a moist, mottled
appearance
appear straight or slightly curved
6. Good growth may also be observed on modified ThayerMartin agar because of the resistance of the
organism to vancomycin, colistin, and trimethoprim
Pleomorphism, with swollen or large coccal cells, is seen in older cultures
All species are catalase-negative, are oxidase-negative, and produce acid from glucose, maltose,
sucrose, and mannose, but not from ribose, xylose, mannitol, or sorbitol
Lysine and ornithine decarboxylase, arginine dihydrolase negative
Characteristics :
7. Pinpoint colonies appear after 2 to 4 days of incubation. After further incubation, colonies appear larger,
circular, smooth, and convex. The colonies are nonhemolytic and have a shiny, spreading edge
consistent with the gliding motility of the organism. Colonies may have a yellowish or pinkish hue. On
Gram’s stain, the bacteria appear as medium-to-long, slightly curved bacilli with tapered or spindle-
shaped cells
Both canine species are arginine dihydrolase-positive, ONPG-positive
C. Canimorsus ferments inulin
C. canimorsus and C. cynodegmi are differentiated by carbohydrate utilization
tests
Characteristics :
8. C. haemolytica is β-hemolytic on sheep blood
C. granulosa strains form intracellular granular inclusions that stain with carbol fuchsin when the
organisms are grown anaerobically in peptoneyeast glucose broth under anaerobic conditions
C. canimorsus is usually recovered from blood cultures, wound cultures, aspirates from cellulitis, and
CSF. C. cynodegmi has been recovered from dogs’ mouths and from several types of human clinical
specimens, including localized dog-bite wounds, cellulitis, blood, BAL specimens, and peritoneal fluid.
In cases of high-grade bacteremia, the bacteria may actually be observed on Wright–Giemsa-stained
smears of peripheral blood.
blood cultures become positive 3 to 7 days after collection
The organism grows slowly on blood and chocolate agar incubated at 35°C in a CO2 incubator with
increased humidity. Poor growth on routine sheep blood agar has been attributed to the use of a
trypticase-soy base; better growth is seen when a heart infusion base is employed. The organisms also
grow better in a medium supplemented with cysteine, and addition of rabbit serum to the medium also
enhances growth
Characteristics :
9. Virulence factors :
Lipo-polysaccharides
Ig A and G proteases
Gliding movement
10. Endocarditis, cervical lymphadenitis, empyema, lung abscess, sinusitis, vertebral osteomyelitis, iliopsoas
abscess, pyonephrosis, liver abscess, and osteomyelitis involving Capnocytophaga species have been
reported in both immunocompromised and nonimmunocompromised patients
C. sputigena as a cause of continuous ambulatory peritoneal dialysis-related peritonitis
C. canimorsus is the principal human pathogen associated with dog bites and close contact with dogs
Pathogenicity :
11. A part of the normal oropharyngeal microbiota and as opportunistic pathogens under the
appropriatecircumstances.
In the oropharynx :
C. ochracea, C. sputigena, C. gingivalis, C. granulosa, C. haemolytica, and C. leadbetteri can be isolated
from gingival crevices, periodontal pockets, and both supragingival and
subgingival plaque specimens, but their role in the development of periodontal disease is
controversial.
Capnocytophaga species may occur by extension from an oral focus to
involve the sinuses and the CNS
Sepsis in immunocompromised patients, particularly those with hematologic (e.g., acute/chronic
myelogenous leukemia, aplastic anemia, Hodgkin’s disease, myeloblastic leukemia, acute lymphocytic
eukemia, adenocarcinoma, multiple myeloma, Hodgkin’s disease) and solid organ malignancies (e.g.,
endometrial carcinoma)
12. Bacteremic episodes in these patients coincide with periods of profound neutropenia
(especially acute myelogenous leukemia or acute lymphocytic leukemia) and
with administration of cytotoxic chemotherapy
Mucositis and oral ulcerations are characteristically found in profoundly immunosuppressed
patients, thereby establishing an efficient entry route for the organism into the bloodstream
Rare cases of Capnocytophaga pneumonia have been reported in compromised patients
as a result of aspiration
Rarely, Capnocytophaga species may be recovered from the lower respiratory tract, lung abscesses,
wound infections, joint fluid, bone, conjunctival, corneal, and vitreal specimens
Capnocytophaga species have been isolated from female genital tract infections as causes of
intrauterine, intra-amniotic, and perinatal infections(e.g., endometritis, amnionitis, chorioamnionitis);
abortion; preterm birth; congenital bacteremia; and neonatal sepsis
13. Predispose individuals conditions :
Hepatic disease secondary to alcoholism (e.g., cirrhosis), previous splenectomy related to
other medical circumstances, Hodgkin’s lymphoma, hairy cell leukemia, pulmonary fibrosis, malabsorption
syndrome, renal disease, diabetes mellitus, COPD, peptic ulcer disease, Waldenstrom’s macroglobulinemia,
other malignancies, and the use of systemic or topical corticosteroids
The frequently noted association of systemic C. canimorsus infection with asplenia suggests
that the reticuloendothelial system (RES) plays an important role in containing the spread of the
organism
As many as 40% of patients have no predisposing conditions that place them at higher risk of infection,
The mortality associated with severe C. canimorsus infection may be as high as 20% to 30%.
Pathogenicity :
14. Major clinical features of C. canimorsus infection include wound infection with cellulitis, meningitis,
bacteremia with septic shock, renal failure, hemorrhagic skin lesions suggestive of meningococcal
disease, pneumoniawith empyema, and both native and prosthetic valve
Endocarditis, Eye infections, including angular blepharitis, chronic corneal ulcers, corneal ulcer with
perforation, and endophthalmitis
Fulminant C. canimorsus sepsis may clinically resemble overwhelming meningococcal disease, with
the development of disseminated intravascular coagulation (DIC), purpura fulminans, rapidly evolving
hemorrhagic skin lesions, symmetrical peripheral gangrene, and the Waterhouse–Friderichsen
syndrome
The clinical presentation of C. canimorsus infection can mimic other serious disease syndromes,
including tularemia, plague, and hantavirus infection
Unusual presentations and complications of C. canimorsus sepsis have included adult respiratory
distress syndrome, myocardial infarction, abdominal symptoms, hemolyticuremic syndrome,
musculocutaneous mononeuropathy, thrombotic thrombocytopenic purpura without DIC, mycotic
abdominal aneurysm, vertebral osteomyelitis/discitis, and dialysis-related peritonitis
Pathogenicity :
15. keratitis and sepsis with bacteremia, have occurred in individuals who sustained bites and scratches
from domestic cats
In 2005, Khawari and colleagues described the first instance of fatal sepsis and meningitis due to C.
cynodegmi in a splenectomized woman who had been bitten on the hand by her pet dog
C. cynodegmi was isolated as a cause of cellulitis, pneumonitis, and bacteremia in a man with insulin-
dependent diabetes mellitus, who had sustained a bite from a stray dog
C. cynodegmi was isolated from lung tissues of a Rottweiler dog with bronchitis and pneumonia due
to a retained foreign body and from a bronchoalveolar lavage (BAL) specimen of a 10-year-old cat
with a pulmonary carcinoma.
Pathogenicity :
16. Diagnostic :
Colony;
wet
Thin
Flat
Diffuse growth with ragged edges
on TS blood agar and BHI blood agar
Indole negative
Oxidase negative
Catalase negative
17. Human oral Capnocytophaga species are generally susceptible to ampicillin, sulbactam, tetracycline,
linezolid, imipenem, and other β-lactam/β-lactamase inhibitor combinations, but are resistant to
polymyxin, colistin, and trimethoprim
Capnocytophaga strains that are resistant to β-lactams produce novel β-lactamase enzymes that confer
resistance to extended-spectrum cephalosporins and penicillins
Treatment :
The imipenem/cilastatin, clindamycin, or combinations containing an inhibitor of beta-lactamases (i.e.
Augmentin, Unasyn) are always effective and their use can be recommended
For Capnocytophaga canimorsus, the drug of choice is penicillin G, given with or without a beta-
lactamase inhibitor depending on resistance
Beta-lactamases encoded in Capnocytophaga spp : CfxA, CfxA2, CepA, CblA, and/or CSP-1
18. Characteristic C. ochracea C. gingivalis c. sputigena C.
haemolytica
C. granulosa C.
canimorsus
C.
cynodegmi
C. leadbetteri C.Genospeci
es AHN8471
HEM SBA - - - (lost on
subculture)
- - - - -
Oxidase - - - - - + + - -
Catalase - - - - - + + - -
NO3 RED V + V
IND +
URE
ADH + + NA NA
ESC V V + V + V
STA + V+ V + + NA NA V +
GLU (A.pr)
MAL
SUC
LAC
RAFF
19. Characteristic C. ochracea C. gingivalis c. sputigena C.
haemolytica
C. granulosa C.
canimorsus
C.
cynodegmi
C. leadbetteri C.Genospeci
es AHN8471
XYL
CELL
GAL
GLYG
23. Capnocytophaga sputigena :
Gram-negative
Gliding motility
Bent bacilli rounded ends
surface; flat, spread orange colonies
Mesh-like structure on the surface of colony
Typical hair-like diffuse structure under stereomicroscope
On BHI blood agar
• Lactose positive
• Glucose positive
• Maltose positive
• Sucrose positive
• GC content 33-38%
24. A) Cells of C. sputigena (Gram stain)
B) Cells of C. sputigena (SEM)
C) Cells of C. sputigena (SEM). Cells of C. sputigena
are bent bacilli, usually with rounded ends. They
produce no spores and stain gram-negative
D) Colonies of C. sputigena (BHI blood agar)
E) Mesh-like structure on the surface of colonies of
C. sputigena (stereomicroscope)
• Colonies of C. sputigena on BHI blood agar surface are
flat, spread orange colonies
• Typical hair-like diffuse structure can be seen
under the stereomicroscope
25. A) Gray-colored, non-hemolytic colonies on a blood agar plate after 48 hr of incubation at 35 °C
with Co2 .
B) Thin , spindle-shaped, from smear preparations of the blood agar plate
28. A) Cells of C. gingivalis (Gram stain)
B) Cells of C. gingivalis (SEM)
C) Cells of C. gingivalis (SEM). Cells of C. gingivalis
are fusobacterium-shaped, and the ends are usually
rounded. Cells are often arranged in an orderly
manner and stain negative by Gram stain
D) Colonies of C. gingivalis (BHI blood agar).
E) Colonies of C. gingivalis (stereomicroscope).
Colonies of C. gingivalis on BHI blood
agar are irregular, gray colonies, with ragged edges
Typical hair-like diffuse colonies can be seen
under the stereomicroscope
29. Pathogenicity :
Oral flora of patients with periodontitis or hematological cancer
Bacteriemia
Leukemia
Pneumonia
Sepsis
Lung abscess
Chronic respiratory failure due to asbestos
30. Diagnosis :
Colony :
Irregular
Gray
yellow/pink
with ragged edges
On BHI blood agar
33. In 1976, two different bacteria colonies: white and a violet were isolated in a water
treatment station in Manaus city (Amazonas Brazil). identified the violet one as Chromobacterium
violaceum
The suspicion that violacein should be a solar protector for the bacterium was reported by
Prof. R. Caldas (UFRJ), who originated a series of studies that demonstrated the photo therapeutic potential
of violacein
C. violaceum is usually found as a saprophyte of soil and water
It was first identified in 1881 and its pathogenic potential was first described by P.G. Woolley in 1905,
who isolated it from a fatal infection in buffalo in the Phillipines
J.E. Lessler first described it as a human pathogen in 1927 in Malaysia
34. gram-negative,
facultatively anaerobic,
fermentative,
oxidase-positive
Rod shaped bacterium
Produces a violet nondiffusible pigment known as violacein, soluble in ethanol and insoluble in water
and chloroform
Catalase positive
non-fastidious
polar flagella
BSL 2
Characteristics :
35. Round
Convex
Smooth
about 1-2 mm in size after 24 h at 37°C
Beta hemolysis
No growth occurred on cetrimide agar
Mueller-Hinton and sheep blood agar. In Trypticase soy broth it grew profusely, producing diffuse
turbidity and a violet ring of growth with a fragile pellicle
Plate cultures smelled distinctly of hydrogen cyanide
Characteristics :
TSI : K/A ( no gas, no H2S )
G + C content 64.83%
37. pathogenicity
Virulence factors :
type III secretion system (T3SS), which is a needle-like multiprotein complex that injects various bacterial
effectors into host cells
C. violaceum has two T3SSs whose genes were clustered in Chromobacterium pathogenicity islands 1
and 2 (Cpi-1 and Cpi-2)
These islands were located next to each other on the chromosome, but while the genes from Cpi-2
were all grouped together, some genes from Cpi-1, encoding the needle complex, were located
distantly from Cpi-1, in a cluster called the Cpi-1a (Betts et al., 2004). C. violaceum Cpi-1/1a and Cpi-2
resemble the well-characterized Salmonella pathogenicity islands Spi-1 and Spi-2
Deletion of genes from Cpi-1/1a, but not from Cpi-2, causes a profound reduction
in C. violaceum virulence in a mouse model of infection, positioning Cpi-1/1a as the major determinant
for C. violaceum pathogeniciy
38.
39. Pathogenicity :
Attacking immunocompromised patients with neutrophil deficits, including CGD, usually as a result of
contamination of wounds with water or soil
Osteomyelitis, abscesses, and septicemia, urinary and gastrointestinal infections, septic spondylitis,
conjunctivitis, and intra-abdominal abscess
A skin lesion is the typical portal of entry
Presenting symptoms :
Fever, sepsis, skin lesions, and abdominal pain
The liver was the most common site of localized abscesses
The most important risk factors for death in C. violaceum, bacteremia were young age
Asymptomatic bacteriuria by C. violaceum in an immunocompetent patient
40. Cpi-2 could be involved in the survival of C. violaceum within macrophages, as described for the
Salmonella Spi-2 system
CopE, plays a key role in C. violaceum invasion of non-phagocytic epithelial cells and is required for C.
violaceum virulence in mice. CopE acts as a guanine exchange factor (GEF) that activates Rac1 and Cdc42
in HeLa cells, resulting in the induction of actin rearrangement
C. violaceum escapes from the phagosome to the cytosol in epithelial cells by a mechanism
involving CipC, a translocon apparatus protein of the Cpi-1 T3SS
Pathogenicity :
Biofilm formation
41.
42. Quorum sensing production of defense molecules against competitors such as extracellular hydrolytic
enzymes (e.g., proteases, esterases, chitinases and pectinases), biosurfactants, virulence factors and
biofilm
QS involves the synthesis and release of small molecules into the environment to interact with receptors
that modify directly or indirectly cellular processes and biosynthetic pathways interfering on mechanisms
of transcription and translation
The main family of QS molecules identified includes the AHLs, also called autoinducers, with
variable acyl chain length from 4 to 16 carbons with or without double bonds, and substituents such as
hydroxyl or keto groups at the 3-position
The QS system of Chromobacterium violaceum ATCC 31532 comprise four main components :
CviI synthase, AHLs diffusible molecule, a CivRtype signal receptor and some target genes which involve
the activation of lytic activity such as chitinases, and exoproteases, virulence factor like type VI secretion
related gene, and genes related to a transcriptional regulator, a guanine deaminase and cviI responsible
for the AHL synthesis and the violacein operon (vioABCDE) among others
44. Produce cyanide2, solubilize gold3, produce chitinolytic enzymes4 and synthesize bioplastics
Has several biotechnological applications such as bioremediation6, production of cellulose7 and
compounds acting as anticancer agent
Antitumoral and antimicrobial activities Violacein
Phenylalanine hydroxylase ( CvPAH )
Metabilites :
45. – The protein, CviI synthase, converts S-adenosyl methionine and fatty acids into AHLs. The QS signal is
triggered when the ALHs reach certain concentration levels in the medium and bind
CviR, a constitutive protein, stimulating the transcription of the vioABCDE operon
46.
47.
48. All these molecules have in common a phenolic ring containing mostly para- or meta-aliphatic side-
chains of variable length mostly with some additional groups such as keto groups or double bonds, or an
aromatic ring
49. More than 150 cases have been reported worldwide from Vietnam, Taiwan, Japan, United States,
Brazil, Argentina, Australia, Senegal and Sri Lanka
Geographical distribution :
50. Diagnosis :
Smooth, round, convex, butyrous, violetcolored colonies
On blood agar, deep violet colonies with beta-hemolysis
Culture of blood, abscess fluid, skin exudate
PCR assay for specific detection
51.
52. Treatment, prevention and control :
sensitive to :
Fluoroquinolones
Tetracyclines
Carbapenems
Gentamicin
SXT
Resistant to β-lactam antibiotics
Prevention :
Anti-adhesion active components of edible seeds
54. Gemella :
– Gemella species are commonly found as commensal organisms of the upper respiratory tract
– The type species is Gemella haemolysans
A gemella species was first described as Neisseria hemolysans in 1938. It was reclassified
as a new genus in 1960 when strains were found to be distinct enough from Neisseria to require
a new genus.
The name was suggested based on the organism being a diplococcus and gemellus is the
diminutive of geminus.
– Gemella spp. As one of the four most common etiologic pathogens responsible for community-acquired
lung abscess ( CALA ) in the West ( 9.8 % of the cases ).
55. Classify :
G. haemlysans ( Berger, 1992 )
G. mrbillorum ( Berger, 1992 )
G. bergeri ( Collins, 1998b )
G. sanguinis ( Collins, 1998a )
G. palalicanis ( Collins, 1999 )
G. cuniculi ( Hoyles, 2000 )
56. Cells stain Gram positive but often decolorize easily and appear Gram negative
Cocci
Single,Pairs, tetrads
Gram positive
Small irregular clusters, small chains
Elongated and rod-shaped forms
Facultative anaerobic
Co2 rich
Non-motile
Do not form endospore
Catalase negative
Oxidase negative
Growth can occur under both aerobic and anaerobic conditions
Characteristics :
57. Gemella haemolysans :
Diplococci with their adjacent sides flattened
Gram positive
short chains, or irregular clusters
optimum growth occurring between 35 – 37 °C
fermentative
Tend to prefer aerobic growth environments
Characteristics :
BSL : 2
58. Part of the normal human flora in the oral cavity and upper respiratory tract
Has been isolated from approximately 30% of nasopharyngeal swabs of sampled people and from
human dental plaque also found within the intestinal trac
Has been isolated as a pathogen from blood cultures of patients with endocarditis, cerebrospinal fluid
(CSF) cultures of patients with meningitis and brain abscess, and in patients with total knee arthroplasty
Pathogenicity :
Functions as an opportunistic pathogen, particularly in immunocompromised hosts
60. – Immunological techniques are not currently available
Leucine aminopeptidase (LAP) production
Pyrrolidonyl arylamidase (PYR) positive
Growth in 6.5% salt broth, being negative
Worldwide occurrence
Diagnostic :
Catalase and Oxidase negative
Colonies on blood agar resemble viridans streptococci
Samples :
Blood cultures
Cerebrospinal fluid
Mucous membranes
Abscess
Wound specimens
Body fluids
61. Phenolic compounds, hypochlorites (1% sodium hypochlorite), alcohols (70% ethanol), formaldehyde (18.5
g/L; 5% formalin in water), glutaraldehyde, iodines (0.075 g/L) (12), and 6.5% salt broth
SUSCEPTIBILITY TO DISINFECTANTS :
The organism does not survive well outside the host
STABILITY AND VIABILITY :
They do not grow at temperatures below 10 or above 45 °C . Bacteria are also sensitive to moist heat
and dry heat
62. DRUG RESISTANCE: sulfonamides and trimethoprim, and aminoglycosides to a lesser extent (i.e.
streptomycin)
DRUG SUSCEPTIBILITY: highly sensitive to penicillin, ampicillin, cephalosporins, tetracyclines,
chloramphenicol, lincomycins, and tetrasulfathiazole. strongly inhibited by macrolide antibiotics,
vancomycin, ristocetin, novobiocin, and tyrothricin, and extent by bacitracin and fusidic acid
Treatment :
63. Gemella morbillorum :
G. morbillorum was first isolated from a patient with measles in 1917, and was once believed to be
associated with measles
G. morbillorum is an opportunistic pathogen
G. morbillorum naturally produces an antimicrobial peptide, giving it prospects of being
developed as a probiotic
A part of the normal flora of the mucous membrane, predominantly of the oropharynx, but
Can also be found in the upper respiratory, gastrointestinal, and female genital tracts
64. Gram-positive coccus
Facultative anaerobe
usually preferring capnophilic or microaerophilic environments
non-motile and non-sporeforming, and can occur singly, in pairs, and in short chains
fermentative
fermentation of glucose it produces L-lactic acid, with smaller amounts of acetic acid
can also produce acid from maltose and sucrose, and mannitol and sorbitol in some strains
Characteristics :
Catalase and oxidase negative
65. IgA1 protease
Formation of biofilms
Endocarditis, meningitis, brain abscess, pleural empyema, nephritis, mediastinitis, liver
Abscess and gastrointestinal carcinoma
Biofilms very rarely occur in a healthy individual, and predominately correlate to poor dental health,
dental manipulation or surgery, colorectal disease or procedures, steroid therapy, diabetes mellitus, or
hepatorenal dysfunction
predisposing factors for infection :
Poor dental health, dental manipulation or surgery, colorectal disease or procedures, steroid therapy,
diabetes mellitus, and hepatorenal dysfunction
Pathogenicity :
It is found commonly in the mouth and cause plaque in the subgingival area
