Gram Negative Bacteria Flashcards
1
Q
What characteristics do Enterobacteriaceae have?
A
Gram Positive rods
Most are motile (peritrichous flagella)
Encapsulated
Virulence factors include LPS, O, H, and K antigens
Many have “serum resistance” (Ab’s can’t attack)
2
Q
What diseases are Enterobacteriaceae associated with?
A
Enteric (GI) infections
Bacteremia
UTI’s
3
Q
Who is at high risk for acute diarrhea?
A
Travelers Consumers of certain foods Immunocompromised Daycare participants Institutionalized persons (nosocomial infections)
4
Q
What foods put a person at risk for getting acute diarrhea?
A
- Chicken, mayonnaise, creams, eggs (Salmonella, Campylobacter, Shigella)
- Hamburger undercooked (EHEC – enterohemorrhagic E. coli
- Fried rice (B. cereus)
- Seafood (Salmonella, Vibrio, Hepatitis A)
- Fermented tofu (C. botulinum)
5
Q
What Gram negative bacteria most commonly cause acute diarrhea?
A
ETEC – enterotoxigenic E. coli Shigella Salmonella Campylobacter Giardia
6
Q
What are the treatments for GI diseases such as acute diarrhea?
A
-Fluid/electrolyte replacement
Dehydration is the most common cause of death from diarrhea
-Antibiotics are not used after onset of symptoms unless systemic/severe
-Antibiotic prophylaxis when traveling to high-risk countries
7
Q
Enteric infection symptoms: Non-inflammatory
A
- Nausea
- Vomiting
- Diarrhea
8
Q
Enteric infection symptoms: Inflammatory
A
Dysentery (severe diarrhea containing mucus and/or blood)
9
Q
Enteric infection symptoms: Invasive
A
Typhoid Fever (enteric fever)
10
Q
What is the mode of transmission (MOT) of most enteric bacteria?
A
fecal-oral contamination
11
Q
What are 3 factors the host might have that increase risk of infection by enteric bacteria?
A
Low gastric acidity
low numbers of normal enteric microflora
immunocompromised
12
Q
Pathogenicity of enteric bacteria:
A
usually ingested as preformed toxins
13
Q
Microbial Toxins
A
Staphylococcal toxins (Staph. aureus)
14
Q
Example of neurotoxin
A
Botulinum toxin (Clostridium. botulinum)
15
Q
Enteric Toxins
A
having a direct effect on intestinal mucosa (elicit fluid secretions)
16
Q
What is/are an example of Enterotoxins?
A
Cholera toxin (Vibrio. cholerae) E. coli toxins
17
Q
What are attributes of Cytotoxins?
A
mucosal destruction (often see dysentery) Shigella dysenteriae
18
Q
What is/are examples of Cytotoxins?
A
Clostridium perfringens
S. aureus
Clostridium difficile
19
Q
What are attributes of Enterobacteriaceae?
A
Ubiquious (they are everywhere) - soil, water, vegetation, normal intestinal flora
Gram negative, facultative anaerobic rods
oxidase negative - no cytochrome oxidase
20
Q
Enterobacteriaceae are members of family commonly associated with human disease:
A
Escherichia Salmonella Shigella Yersinia Klebsiella Serratia Proteus
21
Q
Enterobacteriaceae pathogens are associated with what opportunistic infections?
A
septicemia
pneumonia
meningitis
urinary tract infections (UTI)
can be primary pathogens (unrelated to immune status)
22
Q
Are E. coli and the serotypes Lactose positive or Lactose negative?
A
Lactose positive
note: many intestinal pathogens are lactose negative
ex. Salmonella, Shigella, Yersinia
23
Q
How are E. coli and the serotypes grouped?
A
grouped based on surface antigens (serotypes):
O antigen (lipopolysaccharide)
H antigen (flagellar)
K antigen (capsular)
O157:H7 (EHEC – enterohemorrhagic E. coli)
O148:H28 (ETEC – enterotoxigenic E. coli)
24
Q
Describe E. coli serotype differentiation.
A
immunologic assay
growth on MacConkey agar with sorbitol (called S-Mac media)
most E. coli can ferment sorbitol (form pink colonies)
E. coli O157:H7 does not ferment sorbitol (colonies are clear/colorless)
25
Describe E. coli pathology
- most strains of the pathogenic E. coli are capable of pathology only within the intestinal tract (some exceptions)
- most pathogenic strains associated with disease in developing countries (except EHEC is common in the USA)
- dependent upon strain, different disease severity/symptoms (e.g. pathotype)
26
Pathogenic strains produce virulence factors found on:
Plasmids (a DNA molecule that is separate from, and can replicate independently of, the chromosomal DNA)
Bacteriophages (viruses that infect bacteria)
27
Virulence factors include:
```
Fimbriae (allow bacteria to stack up on each other to shelter themselves from immune system
secretion systems (the process of toxin release) and toxins
```
28
Pathogenic strains of E. coli include:
```
EPEC (enteropathic)
ETEC (enterotoxic)
EHEC (enterohemorrhagic)
EIEC (enteroinvasive)
EAEC (enteroaggregative)
UPEC (uropathogenic)
```
29
What happens when there is destruction of the surface microvilli (small intestines)?
```
fever
diarrhea (infantile)
malabsorption of fluids
vomiting/nausea hard to replace fluids
non-bloody stools
common in developing countries (rare in U.S.)
```
30
Since EPEC pathology - diarrhea is primarily a disease of the young (less the 6 months old), what must be replaced?
fluid replacement is important
31
What are symptoms of EPEC pathology- diarrhea?
~intense vomiting - i.v. fluids are usually required
~disease self-limiting (antibiotics usually not required)
breast feeding seems to have a strong protective effect
IgA and other factors decrease bacterial attachment
32
Enterotoxigenic E. coli (ETEC) is also known as?
“Traveler’s diarrhea”
33
What are the types of ETEC toxins?
heat labile toxins (LT)
similar to cholera toxin (although not as severe)
lack of absorption of fluids = watery diarrhea
heat stabile toxins (ST)
no inflammation, self-limiting
34
ETEC strains are:
- disease is self-limiting, watery diarrhea common symptom
- exposure provides immunity
- adults living in endemic areas, often immune children, through exposure to the many strains, eventually develop immunity
35
Therapy for ETEC includes:
~fluid replacement
~bismuth subsalicylate tablets (Pepto-Bismol, etc.)
~provide antibiotics to travelers in the event they get sick while abroad
36
Enterohemorrhagic E. coli (EHEC) is usually classified as:
usually O157:H7
| strain must have virulence/toxin genes.
37
What are VTECs?
Vero toxin (VTEC) = “shiga-like” toxin (cytotoxin) aka Shiga toxin-producing E. coli (STEC)
38
What does an AB toxin cause?
“A” inactivates 28S rRNA = stop protein synthesis. Death of epithelial cells.
39
Characteristics of Streptococcus:
•Gram-positive cocci, arranged in pairs or chains, that are facultative anaerobes
•Often categorized based on the Lancefield classification
-Divides the streptococci into serotype groups based on the bacteria’s antigens
-Lancefield groups A and B include the significant streptococcal pathogens of humans
40
Strep classification:
Group A (GAS) Strep pyogenes
Group B Strep agalactiae
Group D Enterococcus faecalis
Viridans Strep mutans
41
Hemolysis - beta
| Bacitracin - sensitive
S. pyogenes
42
Hemolysis – beta
| Bacitracin - resistant
S. agalactiae
43
Homlysis – Alpha
| Bacitracin - resistant
S. pnumoniae
44
Hemolysis – Alpha or gamma
| Bacitracin - resistant
E. faecalis
45
Characteristics of Streptococcus Pyogenes:
* S. pyogenes forms white colonies surrounded by zone of beta-hemolysis on blood agar plates
* Only GAS species
* Pathogenic strains often form a capsule
46
Group A streptococci generally only cause disease in the following situations:
* Normal microbiota are depleted
* Large inoculum enable the streptococci to establish themselves before antibodies are formed against them
* Specific immunity is impaired
* Direct contact with mucous
47
Group A streptococci Pathogenicity:
•Structural components
--Protein M, which interferes with opsonization and lysis of the bacteria and a hyaluronic acid capsule, which acts to camouflage the bacteria
•Enzymes
--Streptokinases, deoxynucleases, and C5a peptidase all facilitate the spread of streptococci through tissues
•Pyrogenic toxins that stimulate macrophages and helper T cells to release cytokines
•Streptolysins lyse red blood cells, white blood cells, and platelets
48
Group A Streptococcal Dieseases:
* Pharyngitis (“strep throat”)-inflammation of the pharynx
* Scarlet fever-rash that begins on the chest and spreads across the body
* Pyoderma-confined, pus-producing lesion that usually occurs on the face, arms, or legs (Impetigo)
* Streptococcal toxic shock syndrome-bacteremia and severe multisystem infections
49
What is the major species of Salmonella?
S. choleraesuis
50
Which organisms cause enteric fever?
S. choleraesuis ssp. Choleraesuis, serovar typhi (often just called S. typhi, or a better designation is Salmonella Typhi)
51
How is S. enterica ssp. enterica serotype typhimurium shorted?
It is shortened to S. typhimurium (Salomonella Typhimurium)
52
With Salmonella subtyping, how are serotypes determined?
1. O antigen (LPS outer sugars)
2. Surface Vi antigen (only in sub-types)
- -Capsule antigens (vi=virulence antigens)
3. H antigens (flagella)
53
How do most clinical labs divide Salmonella into serogroups?
Serogroups (A, B, C1, C2, D, and E) based on O-antigen antisera
54
What causes Salmonella diseases?
Ingestion of bacteria from contaminated food/water and affects the human intestinal tract.
55
What happens when bacteria from Salmonella diseases get to the in the intestinal tract?
Organisms get to the small intestines, where the macrophages often ingest bacteria, however the bacteria are protected from host responses (e.g. complement, antibodies, etc)
56
How does Salmonella alter host cells?
changes host cell to allow for “bacteria-mediated endocytosis (absorbing a substance from outside the cell)”
prevents lysosomal enzymes of macrophage from degrading bacteria
57
With Salmonella pathology, the bacteria is disseminated by macrophages to which areas?
The liver, spleen, lymph nodes and bone marrow.
58
What causes systemic symptoms?
These are due to host responses against pathogens
59
What are inflammatory cytokines?
Inflammatory cytokines are secreted by activated macrophages. (Cytokines are chemicals that call other WBCs to come to the area)
60
How rare is typhoid Salmonella infections?
It is very rare in the U.S., however 21 millions infections worldwide (~200,000 deaths)
61
Compared to typhoid Salmonella, how common is non-typhoid Salmonella?
Non-typhoid is much more common. Humans acquire infections from poultry/eggs, dairy, and contaminated work surfaces (cutting boards). In the U.S. ~40,000 reported cases (estimated 2 million)
62
What is Enteric (typhoid) fever?
It is a systemic disease caused by S. Typhi or S. Paratyphi. It is endemic (only occurs in developing countries. ~70% of U.S. cases are acquired from international travel)
63
How are Typhoid Fever and Enteric Fever similar and different?
Similar: Fever, nausea, rash and other systemic symptoms. Was originally called typhoid fever because of the similar symptoms to typhus.
Differ: Different bacteria, different mechanism of spreading
64
How is Enteric fever acquired and who are its host?
The disease is from ingesting contaminated food, and the only known host is humans.
65
Is the infectious dose low or high?
Dose is low. (~103 versus 106-108 for infections with other species of Salmonella)
66
What are the clinical manifestations?
- febrile illness
- disease more severe by S. typhi as compared to S. paratyphi
- after 10-14 days of initial infection, patients have gradually increasing fever, headache, myalgia (muscle pain), malaise (fatigue).
- at around 21 days after infection, GI symptoms present (not seen in all patients) – diarrhea
67
What is one reason why it is difficult to diagnose Typhoid Fever?
The variable numbers of bacteria throughout the infection
68
What are 3 potential cultures (specimens) that can be used to test a positive diagnosis for Typhoid Fever?
1) Stool
2) Urine
3) Bone marrow
69
What does MDR mean?
Multi-drug resistant
70
Are some strains of S. Typhi MDR?
Yes
71
What causes gastroenteritis?
Salmonella
72
What are 4 symptoms of acute gastritis?
Vomiting, abdominal pain, fever, and diarrhea
73
What causes shigella?
Acute infectious inflammatory colitis
74
Is mortality from shigella more common in children or adults?
Children
75
Is shigella a pathogen of animals or humans?
Humans
76
Is it easy to spread shigella to others?
Yes, it is highly communicable
77
What are the clinical manifestations of Shigella?
abdominal cramps, diarrhea, fever, bloody stools and large numbers of WBC in stool
78
What do Shigella virulence proteins cause?
Ruffling of epithelial cells, allows for endocytosis of the bacteria, actin rearrangement allows for cell-to-cell spread.
79
S. dysenteriae produces what toxin?
S. dysenteriae produces shiga toxin (similar to EHEC)
80
What are the enteric pathogens of Yersinia?
Y. enterocolitica, Y. pseudotuberculosis
81
Y. pestis is also known as what?
The bubonic and pneumonic plague
82
The zoonotic disease Yersinia is primarily found in what animals?
Fleas, rodents, swine, cattle, etc
83
The formation of bubos is found in what disease?
Y. pestis
84
What is the mortality rate of untreated patients suffering from the pneumonic plague?
High mortality rate - 90%
85
Is Y. entrocolitica or Yersinia sp. more common?
Y. entrocolitica
86
Does Y. entrocolitica cause severe or acute enterocolitis?
acute enterocolitis and mysenteric lymphadenitis (can mimic appendicitis)
87
How many different serotypes of Y. enterocolitica are there?
Over 60 (serotypes 3,8, &9 account for most human infections
88
Y. entrocolitica is associated with what risk factors?
Ingestion of contaminated food/ milk (can grow at lower temperatures 4C), blood transfusion septicemia
89
Yersinia can be diagnosed from what type of samples?
Blood or stool
90
What is cold enrichment?
Growth culture at 4-7C for 28 days w/ weekly subculture on SS agar
91
What are the therapies for Yersinia?
Plague- antibiotics and rodent control Enteric- often self limiting
92
What are two major pathogenic species of Neisseria?
N. gonorrheae- associated with STDS
| N. meningitidis- associated with respiratory and CNS infections
93
In vitro growth is found in:
Obligate aerobes
Sensitive to drying ( delicate) and some products in blood(that is why one uses Chocolate agar for culture
fastidious-picky
Out-competed by normal flora so grow in presence of select antibiotics(Thayer-Martin agar)
Need 5% CO2
94
What does LPS stand for?
Lipopolysaccharide
95
What does LOS stand for?
Lipoligosaccharide
96
In Endotoxins, what is the LPS like?
Lipid A, core sugars, outer sugars
97
In Endotoxins, what is the LOS like?
Lipid A, core sugars, present in Neisseria
98
In Neisseria gonorrhoeae, what are the incidences of the disease?
incidence remains high in some groups defined by geography, age, race/ethnicity, or sexual risk behavior.Increasing proportion of gonococcal infections caused by resistant organisms
99
How is it transmitted?
Efficiently transmitted by:
Male to female via semen
Female to male urethra
Rectal intercourse
Fellatio(jpharyngeal infection)
Perinatal transmission( mother to infant)
Gonorrhea associated with increased transmission of and susceptibility to HIV infection
100
What are the virulence factors of Gonococcus?
Pilus
Phase variation and Antigenic variation(of pilus and opacity protein)
phase variation-differences in colony appearance
antigenic variation-varying pili antigenic type
development of a vaccine will be difficult
Endotoxin (LOS)
IgA protease-cleaves at hinge region
Serum resistance
101
What are the characteristics of the genital infection Urethritis, found in men?
inflammation of urethra,
typically purulent or mucopurulent urethral discharge
asymptomatic in 10% of cases
102
What are the characteristics of the genital infection Epididymitis, found in men?
inflammation of the epididymis
unilateral testicular pain and swelling
infrequent
103
Most genital infection in women are?
Asymptomatic
104
What is Cervicitis?
Inflammation of the cervix
105
What is Urethritis?
Inflammation of the urethra
106
What are complications in women due to gonorrhea?
- Pelvic Inflammatory Disease (PID)
| - Fitz-Hugh-Curtis Syndrome
107
What are the gonorrhea syndromes in men and women?
- Conjunctivitis
| - Disseminated gonococcal infection (DGI)
108
Gonorrhea infection in perinatal children causes?
-Infections of the conjunctiva, pharynx, respiratory tract
109
What are diagnostic methods for gonorrhea?
Culture tests
110
Laws and regulations in all states require that persons diagnosed with ????? are reported to public health authorities by clinicians, labs, or both.
Gonorrhea
111
What are the diseases caused by N. meningitides?
- Meningococcal meningitis
| - Meningococcemia, sepsis
112
What are the virulence factors of Meningococcus?
- Polysaccharide capsule
- Endotoxin (LOS)
- IgA protease
- Serum resistance
113
To control Meningococcus how does the vaccine work?
Does NOT display same types of phase/antigenic variation as seen in NG
114
To control Meningococcus how do microbials work?
Somewhat susceptible to penicillins (although some degree of resistance reported)
115
Members of the Vibrio genus share many characteristics with what type of bacteria?
Enteric bacteria such as Escherichia and Salmonella
116
Where are Vibrio found?
Water environments
117
What is the most common species to infect humans?
Vibrio cholerae
118
Vibrio causes what?
Cholera
119
How do humans become infected with V. cholerae?
By ingesting contaminated food and water
120
What type of communities does this occur in?
With poor sewage and water treatment
121
What type of inoculum is required to cause the disease and why?
A large inoculum because the bacteria are susceptible to the acidic stomach environment
122
What is the most important virulence factor of V. Cholerae?
Cholera toxin
123
What are the symptoms of Cholera?
- Some infections are asymptomatic or cause mild diarrhea
- Can cause severe disease resulting in abrupt watery diarrhea and vomiting
- “Rice-water stool” is characteristic
- Results in severe fluid and electrolyte loss
- Can progress to coma and death
124
How does one diagnose for Cholera?
Usually based on the characteristic diarrhea
125
What is the treatment for Cholera?
- Fluid and electrolyte replacement
| - Antimicrobial drugs are not as important because they are lost in the watery stool
126
How do you prevent Cholera?
Adequate sewage and water treatment can limit the spread of V. cholerae
127
What is the most common cause of gastroenteritis in the United States 5-7% of cases?
Campylobacter jejuni
128
What serves as reservoirs for the bacteria?
Many animals
129
How do humans become infected with Campylobacter jejuni?
Consuming contaminated food, milk, or water
130
What is the most common source of infection?
Poultry
131
What does the infection cause?
Produce dysenteri and frequent diarrhea that is self-limiting
132
How does the bacteria spread?
- Fecal-oral
- Person-to-person sexual contact
- Unpasteurized raw milk and poultry ingestion
- Waterborne exposure to sick pets, especially puppies
133
What would be considered an infectious dose of Campylobacter jejuni?
1,000-10,000 bacteria
134
What is the incubation period?
1-7 days (up to a week)
| *Probably related to the dose of organisms ingested
135
A person infected with Campylobacter jejuni have what type of symptoms?
- A brief prodrome of fever as high as 40°C
- Headache, and myalgias lasting up to 24 hours
- Crampy abdominal pain (abdominal pain and tenderness may be localized)
- Pain in the right lower quadrant may mimic acute appendicitis (pseudoappendicitis).
- Up to 10 watery, frequently bloody, bowel movements per day
136
Patients with C. jejuni infection who report vomiting, blood diarrhea, or both tend to have what type of illness?
A longer illness and require hospital admission
137
What organism causes most peptic ulcers?
Helicobacter pylori
138
Does Haemophilus influenza have a capsule?
Yes
139
What was the most common form of meningitis in infants prior to the use of an effective vaccine?
Haemophilus influenzae
140
What disease is caused by Haemophilus aegypticus?
conjunctivitis with pus
141
What disease is caused by Haemophilus ducreyi?
STD with chancre, only painful in men
142
What is Bordetella?
Small, aerobic, nonmotile coccobacillus
| B. Pertussis (the most important)
143
What is B. Pertussis?
- Causes pertussis, also called whopping cough
- Most cases of disease are in children
- Produce various adhesions and toxins, including pertussis toxin, that mediate the disease
- Bacteria are first inhaled in aerosols and multiply in epithelial cells
- Then progress through three stages of disease
144
What are the stages of Bordetella?
Catarrhal
Paroxymal
Convalescence
145
What is the clinical significance of B. pertussis-causes whooping cough?
Acquired by inhalation of droplets containing the organism
The organism attaches to the ciliated cells of the respiratory tract.
During an incubation period of 1-2 weeks, the organism multiplies and starts to liberate its toxins.
146
Purtussis toxin in catarrahl contains how many A subunits and how many B subunits?
One A subunit and Five B subunits
147
The increase of what in Catarrhal from the combined effects of pertussis toxin and bacterial adenylate cyclase inhibits host cell phagocytic cell responses and the inhibition of natural killer cell activity?
cAMP
148
When is Dermonecrotic toxin in Catarrhal released?
is released upon cell lysis causing strong vasoconstrictive effects
149
What is Trachael cytotoxin related to?
to the B. pertussis peptidogycan
| -might contribute to the killing and sloughing off of ciliated cells in the respiratory tract.
150
What is Lipooligosaccharide?
Has potent endotoxin activity
151
Stage of Proxymal:
Lasts 4-6 weeks.
The patient has rapid, consecutive coughs with a rapid intake of air between the coughs (has a whooping sound).
mucous has accumulated, and the patient is trying to cough up the mucous accumulations.
The coughs are strong enough to break ribs!
Other symptoms due to the activity of the released toxins include:
Increased peripheral lymphocytes
Metabolic alteration such as increased insulin release and the resulting hypoglycemia
Increased capillary permeability and increased susceptibility to histamine, serotonin, and endotoxin shock
152
Stage of Convalescence:
-Symptoms gradually subside.
This can last for months
-B. pertussis rarely spreads to other sites, but a lot of damage may occur, such as CNS dysfunction which occurs in ~10 % of the cases and is due to an unknown cause.
-Secondary infections such as pneumonia and otitis media are common.
153
What is B. parapertussis?
causes a mild form of whooping cough
154
What is B. bronchoseptica?
Widespread in animals where it causes kennel cough.
| Occasionally causes respiratory or wound infections in humans
155
What are the current treatments for Bordetella?
Erythromyin – only effective in early stages of the disease before the toxin(s) have been released
Vaccination P part of DPT (killed, encapsulated organism); a subunit vaccine has also been developed (purified pertussis toxin).
156
What is the diagnosis for Bordetella?
Symptoms of pertussis are usually diagnostic
157
What are the treatments for Bordetella?
* Primarily supportive
| * Antibacterial drugs have little effect on the course of the disease
158
What is the prevention for Bordetella?
* Immunization with the DPT vaccine
| * Cases in the United States have increased due to a refusal by some parents to have their children immunized
159
What is the classification of Francisella?
only 1 pathogenic species – F. tularensis
160
What are the morphology and characteristics of Francisella?
* Minute, pleomorphic g- rod that stains poorly
* Staining may be bipolar
* Nonmotile
* Nonencapsulated
* Won’t grow on ordinary media – requires cysteine or cystine for growth
161
Where is Francisella found?
Found living in water as an intracellular parasite of animals.
162
What are the causes of Francisella?
* Spread to humans occurs mainly through the bite of an infected Dermacentor or by contact with an infected animal
* The bacteria can spread through unbroken skin and mucous membranes, making it highly infectious
* Tuleremia produces symptoms common to other bacterial and viral diseases and may be misdiagnosed
163
How is Francisella acquired?
1. Entry through skin abrasions (ulceroglandular form of the disease) - after ~ 48 hours a lesion occurs at the inoculated site.
2. Ingestion (typhoidal form of the disease)
•the focus of infection is the mouth, throat, and GI tract.
3. Inhalation (pneumonic form of the disease)
•This is the most severe form of the disease and it manifests as a pneumonia with a high mortality rate of 30% in untreated cases.
164
If not contained, what can Francisella progress to?
Septicemia, pneumonia, and abscesses throughout the body.
165
What is the antimicrobial susceptibility of Francisella?
* Streptomycin or tetracycline
* An attenuated, live vaccine that protects against the inhalation form of the disease is available for those exposed to the organism.
* A vaccine is available to at risk individuals
* Preventing infection is done by avoiding the major reservoirs of the bacteria.
166
What type of organism is Brucella?
Intracellular
167
What 4 species of Brucella can infect humans?
* B. abortus
* B. suis
* B. melitensis
* B. canis
168
What is the morphology and characteritics of Brucella?
•Small g-cb that stain poorly
169
What are the 2 antigens that are part of the LPS are recognized?
A and M
170
Which antigen has the highest concentration of M, which causes an infection?
B. melitensis
171
What is the virulence factor of Brucella?
Endotoxin
172
Brucella has a tropism for what type of sugar alcohol?
erythritol
•Animal fetal tissues and placenta, other than those in humans, are rich in erythritol and, therefore, the organisms often cause abortions in these animals.
173
What does Brucella cause?
Causes Brucellosis or undulent fever in man following ingestion of contaminated milk or cheese from goats (B. melitensis), cows (B. abortus), pigs (B. suis), or canines (B. canis).
174
How do you treat Brucella?
Tetracycline for 21 days, sometimes combined with streptomycin.
175
Are Pseudomonads problematic in hospitals?
Yes, because they can be found in numerous locations
176
What does Pseudomonas aeruginosa often infect?
Often infects the lungs of cystic fibrosis patients
177
Where does Treponema pallidum pallidum live?
Lives naturally only in humans as an obligate parasite
178
Name the four stages of Syphilis
Primary
Secondary
Latent
Tertiary syphilis
179
Symptoms associated with the initial infection
Primary
180
Related to spread of the organisms away from the site of the original infection
Secondary
181
The symptoms in primary syphilis are:
Chancre that should heal by itself in 3-6 weeks
painless
genitals
Mouth
Skin
rectum
Enlarged lymph nodes near the chancre the chancre
182
The symptoms in Secondary Syphilis
```
Spotted rash all over
Fever
general ill feeling
loss of appetite
muscle aches
joint pain
enlarged lymph nodes
hair loss may occur
```
183
The symptoms of Tertiary Syphilis
Cardiovascular syphilis causes aneurysms or valve disease
Central nervous system disorders (neurosyphilis)
Infiltrative tumors of skin, bones, or liver (gumma)
184
How is syphilis is diagnosed
Primary, secondary, and congenital can be readily diagnosed with antibody tests against bacterial antigens
Tertiary syphilis is difficult to diagnose
185
What is the drug of choice for treatment of syphilis?
penicillin
186
Will penicillin work on tertiary syphilis?
| Why not?
No
| It is hyperimmune response and not an active infection
187
How can you prevent syphilis?
Abstinence and safe sex are the primary ways to avoid contracting syphilis
188
What is Borrelia?
Lightly staining, Gram-negative spirochetes
189
Borrelia causes two diseases in humans
Lyme disease
| Relapsing fever
190
What are the 3 phases of lyme disease
| In untreated patients?
* In most cases an expanding red “bull’s eye” rash occurs at the site of infection
* Neurological symptoms and cardiac dysfunction
* Severe arthritis that can last for years
* Pathology of this stage is largely a result of the body’s immune response
191
What is the pathology of Lyme Disease?
The increase of cases is a result of humans coming in closer association with ticks infected with Borrelia
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What can treat the first stage of Lyme Disease?
Antimicrobial drugs can effectively treat the first stage of Lyme disease
193
Why is treatment difficult of the later stages of Lyme Disease?
Treatment of later stages is difficult because symptoms result from the immune response rather than the presence of bacteria
194
What are the two types of Relapsing Fever?
Epidemic relapsing fever
| Endemic relapsing fever
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What are the Mortality Rate of Epidemic Relapsing Fever?
Mortality rate is 1% with treatment; 30-70% without treatment
196
What transmits Epidemic Relapsing Fever?
Transmitted by lice!!
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What can cause Endemic Relapsing Fever?
Several Borrelia species can cause this disease
198
How is it transmitted?
Transmitted to humans by soft ticks of the genus Ornithodoros
199
How are the two types of Relapsing fever characterized?
Both types of relapsing fever are characterized by recurring episodes of fever and septicemia separated by symptom free intervals
200
What is the primary method of diagnosis?
Observation of the spirochetes
201
What can treat Relapsing fever?
Successful treatment is with antimicrobial drugs
| Prevention involves avoidance of ticks and lice, good personal hygiene, and use of repellent chemicals
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Characteristics of Mycoplasma:
1. Smallest free-living microbes
2. Lack cytochromes, enzymes of the Krebs cycle, and cell walls
3. Often have sterols in their cytoplasmic membranes which other prokaryotes lack
4. Require various growth factors that must be acquired from a host or supplied in laboratory media
5. Can colonize the mucous membranes of the respiratory and urinary tracts
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What does Mycoplasma pneumonia attaches to?
Attaches specifically to receptors located at the bases of cilia on epithelial cells lining the respiratory tracts of humans
204
What can Mycoplasma pneumonia cause?
Causes primary atypical pneumonia, or walking pneumonia
205
Symptoms of primary atypical pneumonia or walking pneumonia
Symptoms such as fever, headache, and sore throat are not typical of other types of pneumonia
206
How is primary atypical pneumonia or walking pneumonia spread?
Spread by nasal secretions among people in close contact
207
145. Why is diagnosing Mycoplasma pneumoniae difficult?
Mycoplasmas are small and grow slowly
208
Why is prevention of Mycoplasma pneumoniae difficult?
Patient can be infective for long periods of time without signs or symptoms
209
Characteristics of Rickettsias
Extremely small
Appear almost wall-less due to small amount of peptidoglycan present
Obligate intracellular parasites-unusual as they have function genes for protein synthesis, ATP production and reproduction
Three genera cause disease in humans-Rickettsia, Orienta and Ehrlichia
210
148. Signs and Symptoms of Rocky Mountain Spotted Fever usually develop 2 to 14 days after a tick bite
```
Chills & Fever
Severe Headache
Muscle Pain
Mental Confusion & Hallucinations
Rash
Abnormal sensitivity to light
Diarrhea
Excessive thirst
Loss of appetite
Nausea & Vomiting
```
211
Signs and Symptoms of Endemic Typhus spread by fleas
```
Chills
Cough
Delirium
High Fever (104 degrees F)
Joint Pain (arthralgia)
Light may hurt eyes
Hypotension
Rash that begins on the chest & spreads to the rest of the body (except palms of hands and soles of feet)
Severe headache
Severe muscle pain stupor
```
212
Signs and Symptoms of Epidemic Typhus spread by lice
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Abdominal Pain
Backache
Dull red rash that spreads from the middle of the body
Extremely high fever (105-106 degrees F), may last up to 2 weeks
Hacking, dry cough
Headache
Joint Pain (arthralgia)
Nausea
Vomiting
```
213
Characteristics of Chlamydia
Do NOT have cell walls- have two membranes but without any peptidoglycan between them
Grow & multiply only within the vesicles of host cells
Have a unique developmental cycle involving two forms-both forms can occur within the phagosome of a host cell
214
Characteristics of Chlamydia trachomatis
Has limited host range-one strain infects mice, all others infect humans
Infect the conjunctiva, lungs, urinary tract, or genital tract
Enters the body through abrasions and lacerations
Clinical manifestations result from the destruction of infected cells at the infection site, and from the resulting inflammatory response.
215
What two main types of diseases does Chlamydia trachomatis cause?
Sexually transmitted diseases- causes the most common sexually transmitted disease in the US
Trachoma-Ocular Disease-Occurs particularly in children-Endemic in crowded, poor communities with poor hygiene, inadequate sanitation and inferior medical care.
216
Sexually Transmitted Diseases
Lymphogranuloma veneruem-Characterized by a transient genital lesion and swollen, painfully inflamed, inguinal lymph nodes
Occurs in three stages-
-Initial Stage- produces a lesion at the infection site that is a small painless, and heals rapidly
-Second Stage-buboes develop at the infection site
-Third Stage-only some cases progress to this stage-characterized by genital sores, constriction of the urethra and genital elephantiasis.
217
Lymphogranuloma veneruem
Most infections in women are symptomatic but men may or may not have symptoms
Women can develop pelvic inflammatory disease if reinfected with C. trachomatis
218
What does the trachoma disease affect?
The eye
219
What can it cause?
Nontraumatic blindness in humans
220
How does bacteria affect the eye?
Bacteria multiply in the conjunctival cell resulting in scarring
221
What does the scarring cause?
Causes the eyelashes to turn inwards and abrade the eye eventually resulting in blindness
222
Who does trachoma typically affect?
Children who have been infected during birth
223
What else may result in the disease?
Infection of the eye with bacteria from the genitalia.
224
How is trachoma diagnosed?
There must be bacterial inside cells from the site of infection.
225
How is trachoma treated?
- Antibiotics can be administered for genital and ocular infections
- Surgical correction of eyelid deformities from Trachoma may prevent blindness
226
How can Trachoma be prevented?
Abstinence and safe sex can prevent a chlamydial infection
227
How can blindness be prevented?
By prompt treatment with antibacterial agents and preventing reinfections
228
What type of bacteria is Legionella pneumophila?
Aerobic, slender, pleomorphic bacteria
229
Where does L. pneumophila inhabit?
Water
230
How do humans acquire the disease?
By inhaling the bacteria in aerosols from various water sources.
231
Are L. pneumophila intracellular parasites?
Yes
232
What does Legionnaires’ disease result in?
Pneumonia
233
Are immunocompromised individuals more susceptible to the disease?
Yes
234
Is elimination of the bacteria feasible?
No, but reducing their number is a successful control measure
235
What type of bacteria is Bartonella?
Gram negative aerobic bacilli
236
Where is it typically found?
It is found in animals but only cause disease in humans
237
Which species are pathogenic?
B. bacilliformis
B. quintana
B. henselae
238
What is B. bacilliformis also known as?
Bartonellosis-Carrion’s disease
239
How is it transmitted?
By blood sucking sand flies
240
What are the signs and symptoms of the acute phase?
Fever, pallor, malaise, nonpainful hepatomegaly, jaundice, lymphadenopathy, splenomegaly
241
What else is this phase characterized by?
Severe hemolytic anemia and transient immunosuppression
242
What is the case fatality rate?
Of untreated patients, greater than 40%, but reach 90% when opportunistic infection with Salmonella occurs
243
What is B. quintana also known as?
Trench fever
244
How is B. quintana spread?
From person to person by human body lice
245
What may this disease result in?
Disease in immunocompromised patients
246
How does the disease classically present?
As a five day fever of the relapsing type
247
What is B. henselae also known as?
Cat scratch fever
248
How is it introduced to humans?
Through cat scratches or bites
