ID 1 Flashcards
1
Q
Biological agent that can produce a disease
Ex: bacteria, fungus, virus, protozoa, prion
A
Pathogen
2
Q
A measure of an organism’s capacity to cause disease
- function of a microbe’s pathogenic factors
A
Virulence
3
Q
The collection of microbes residing in an on mammalian organisms; microorganisms of a particular site, habitat, or geological period
A
Microbiota
4
Q
What are the locations of microbiota in humans?
A
gut, skin, and genitals
5
Q
Examples of infectious agents include:
A
viruses, bacteria, fungi, and parasites
6
Q
DNA or RNA with a protein coat (capsid) is called a _____
A
Viron
7
Q
DNA or RNA with a protein coat (capsid) = virion
Must infect host cells ribosomes to replicate
Outnumber bacteria 10:1
ABX will not work
A
Viruses
8
Q
Prokaryotes that are most numerous organisms on earth, occupying every environment, have the ability to replicate very quickly (<30 minutes)
A
Bacteria
9
Q
What are the two types of fungi?
A
Yeasts: single round cells
Molds: many cells in long threads (called a hyphae)
10
Q
Fungal spores in the air or soil have the ability to infect ___________ and __________ commonly resulting in opportunistic or primary infections
A
lungs and skin
11
Q
Organisms that live in/on a host at the detriment to the host
A
Parasites
12
Q
List and describe the classes of parasites
A
- Protozoa: one-cell; replicate in humans; fecal-oral route via arthropod vector
- Helminths: multicellular; cannot replicate in humans; visible to naked eye (worms)
- Ectoparasites: depend on blood meal from human host; often vectors for other pathogens (fleas, mites, lice)
13
Q
Explain the function of the capsid and envelope in viral structures
A
capsid - protein coat which functions for protections, attachments, and penetration
envelope - fat and protein which function as spikes for attachment
14
Q
What mediates the interaction between capsid and envelope?
A
matrix protein from the viral envelope
15
Q
Are enveloped or non-enveloped viruses more stable?
A
non-enveloped are more stable; enveloped are sensitive to heat, solvents, detergents, etc.
16
Q
Explain the difference between enveloped and non-enveloped viruses, including structure, site of replication, and examples
A
DNA: double stranded with replication in the nucleus; more stable than RNA
ex: EBV and HPV
RNA: single stranded with replication in the cytoplasm; less stable so more virulent, high mutation rate
ex: HIV and HCV
17
Q
List the steps of viral infection
A
Transmission of virus and entry into host
Replication of virus and cell damage (symptom onset)
Spread of virus to other cells/organs
Immune response (can also be source of symptoms)
Persistence of virus or resolution (chronic/latent disease states)
18
Q
What are the steps of gram staining?
A
Crystal violet –> Iodine –> alcohol wash –> safranin
19
Q
What are the colors of gram +/- bacteria
A
positive is purple
negative is red/pink
20
Q
Thick cell wall of peptidoglycan with no outer lipid membrane and produces exotoxins
A
gram positive
21
Q
What are the examples of GP cocci bacteria?
A
Staph and Strep
22
Q
Thin peptidoglycan layer with outer lipid membrane present which produces exotoxins and endotoxins
A
Gram negative
23
Q
Example of GN cocci bacteria
A
N. meningitidis
24
Q
Example of GN coccobacillus bacteria
A
H. influenzae
25
What factors affect microbial growth
oxygen, temperature, pH, presence of light, etc
26
protective coating made of sugars
capsules
27
"inactive" forms of bacteria that can survive for years (ex: latent TB)
spores
28
proteins that can harm the host and help bacteria invade tissues
toxins
29
iron-binding factors that allow bacteria to compete with host for iron
siderophores
30
what can cause dental plaques, often making infection persistent, difficult to treat
biofilms
31
What are the mechanisms that can be used to avoid innate host defense?
Antiphagocytic factors: normal host surface components (bacteria looks like host) and polysaccharide capsules (difficult to phagocytize)
IgA1 proteases: pathogens can inactive mucosal surface antibodies
32
What are the different routes of transmission that can be used to infect new hosts?
Direct - contact or droplet
| Indirect - airborne, vector (animate), vehicle (inanimate)
33
Alterations in the microbiota of tissues can lead to life-threatening diseases such as infections or cancer
Dysbiosis
34
What are the most common microbiota of the blood?
pseudomonas, Serratia, staphylococcus, and Acinetobacter
35
The blood microbiome is not well-understood but it plays a role in multiple diseases such as:
Cancer, depression, cardiovascuar events, and diabetes
36
The microbiota of the skin can function in two different ways, what are they?
communalistic: beneficial to bacteria with no harm/help to host
mutualistic: beneficial to bacteria and host
37
What are the most common microbiota of the nasopharynx?
Corynebacterium and staphylococcus
38
What microbiota are most commonly located in the mouth? Describe their shape and stain classifications
Streptococcus - GP cocci
Corynebacterium, lactobacillus - GP rods
Neisseria - GN cocci
Prevotella - GN rods
39
What is the most common microbiota in the stomach?
Veillonella
40
How is the microbiome of the stomach and gastric acid secretion related?
gastric cancer and H. pylori can increase firmicutes
decreased gastric acid secretion, gastric atrophy leads to increased microbes that are normally killed by acid
41
What contains a large surface area for digestion and nutrient absorption?
small intestine
42
What microbiota is most commonly found in the SI?
rapidly dividing facultative anaerobes thrive here
lactobacillius, streptococcus, veillonella, clostridium
43
What organ contains the highest density of microbiota in the entire GI tract? The microbes in this location prioritize the digestion of starches
Colon
44
What are the most common microbiota in the colon?
lachnospiraceae and akkermansia
45
Lactobacillus is most commonly located in the _________
Vagina
46
What can decrease the prevalence of lactobacillus in the vagina?
ABX use and sexual intercourse
47
What type of infection inhibits lactobacillus growth and vice versa
candida infections
48
Is bacterial vaginosis due to a disturbance of lactobacillus
No - it is from abnormal microbes
49
What is the cause of chronic mastoiditis?
usually from recurrent otitis media and prior ABX use
P. aeruginosa, S. aureus, enterobacteriaceae, anaerobes, and mycobacterium tuberculosis
50
Explain the different causes of acute and chronic otitis externa
acute - primarily bacteria (P. aeruginosa, S. aureus) but can be fungal in tropical environments
chronic - consider allergies or underlying inflammatory derm conditions. usually from the same organisms as acute but more likely to be fungal
51
S. pneumonia, H. influenza, and M. catarrhalis can commonly infect the ear to cause ___________
otitis media
52
S. pneumonia, H. influenzae, and M. catarrhalis are the trio of bacteria which infect the ___________
upper respiratory system
53
Sinusitis can be classified in three ways. List them and describe the bacteria which cause this disease
Acute - S. pneumonia, H. influenzae, and M. catarrhalis
Chronic - staphylococcus and anaerobes
Immunocompromised or nosocomial - P. aeruginosa, other anaerobes, GN rods
54
Is pharyngitis more commonly viral or bacterial?
viral
55
What is the relationship between viral and bacterial pharyngitis?
viral is most common
| bacterial is more severe, often arises after initial viral infection
56
Are bronchitis cases more commonly viral or bacterial?
viral = rhinovirus, adenovirus, influenza A/B, RSV
bacterial is more common in patients with underlying health conditions = H. influenzae
57
What is the most common community acquired pathogen?
streptococcus pneumonia
58
1/3 of streptococcus pneumonia infections are due to ____________
respiratory distress
think COVID and influenza can cause pneumonia during illness or shortly after initial recovery
59
Endocarditis is a disease commonly resulting from three different mechanisms. What are they?
Native valve - S. aureus
IV drug users - S. aureus, enterococci, and streptococci (bacteria from the skin can enter blood stream)
Prosthetic valves
60
When patients are given a prosthetic valve they can, unfortunately, suffer from early or late infections. Explain how to differentiate the two
Early - <2 months after implantation --> staphylococci, gram negative, fungi
Late - >2 months after implantation --> streptococcus and staphylococci
61
What is the most common pathogen causing epiglottis?
H. influenzae (but decreasing due to vaccinations)
Immunocompromised patients --> P. aeruginosa, candida
62
The most common cause of viral gastroenteritis
Norovirus, rotavirus, adenovirus
- typically causes watery diarrhea
- vomiting is more common
- milder disease than bacterial
63
The most common cause of bacterial gastroenteritis
Salmonella, campylobacter, shigella
- diarrhea may be bloody (due to shigella or E. coli)
- more likely to cause fever
64
Cholecystitis is commonly caused by
E. coli, klebsiella, and E. faecalis
Anaerobes more common in patients with DM, age >70, or previous surgery
65
Inflammation of the bile duct system
Cholangitis
66
Cholangitis is commonly caused by
the same organisms as cholecystitis which is --> E. coli, Klebsiella, E. faecalis
E. coli accounts for nearly half the cases of cholangitis
67
What is the difference between diverticulitis and diverticulosis
Diverticulitis - outpouching with inflammation
| Diverticulosis - outpouching without inflammation
68
Diverticulitis is essentially colonic perforation which results in the normal colonic flora to be ____________
released into peritoneal cavity
69
What are the most common pathogens associated with diverticulitis
E. coli, B. fragilis, and anaerobes
70
Chlamydia trachomatis is the most common pathogen to cause
cervicitis
71
pelvic inflammatory disease is an upper genital tract infection mainly in young, sexually active women due to the pathogens - ____________ and ____________
chlamydia trachomatis and Neisseria gonorrhea
72
Although PID is most common in young women, it can also occur in post-menopausal women (rare) due to which pathogens
E. coli and colonic anaerobes
73
PID is considered a ___________ infection so it requires _____________ ABX
polymicrobial; broad-spectrum
74
Meningitis can be viral or bacterial, what pathogens cause bacterial meningitis?
N. meningitides and S. pneumoniae
| infants and elderly: E. coli and Listeria monocytogenes
75
What used to be the most common cause of meningitis but has significantly decreased due to vaccination?
H. influenzae
76
Most common pathogens associated with osteomyelitis
chronic: S. epidermidis, S. aureus
septic arthritis: S. aureus
prosthetic joints: S. aureus, S. epidermidis
77
What is the most common bacterial pathogen on the skin
BACTERIAL IS MOST COMMON - S. aureus
78
What is the most common viral pathogen on the skin?
HSV, herpes zoster (shingles), varicella zoster (chicken pox)
79
What is the most common fungal pathogen found on the skin?
trichophyton rubrum (athletes foot and ringworm)
80
What are the most common types of nosocomial infections
urinary, bloodstream, surgical wounds, pneumonia, MRSA, and C. diff
81
```
For nosocomial infections that affect the bloodstream what are the
risk factors
infectious agents
diagnostic evaluations
treatment
```
risk factors - indwelling vascular line, critical illness, repeated treatment with broad-spectrum antibiotics
infectious agents - Staphylococcus aureus
diagnostic evaluation - blood cultures, consider CXR
treatment - remove indwelling catheter, consider ABX lock therapy, most common to use vancomycin as ABX treatment, and refer to infectious disease if necessary
82
```
Pneumonia --
risk factors
infectious agents
diagnostic evaluations
treatment
```
risk factors - ICU patients, mechanical ventilation
infectious agents - S. aureus and MRSA, gram-negative tods, and pseudomonas
diagnostic evaluations - at least two: fever, leukocytosis, purulent sputum, cultures of blood, pleural fluid, and sputum
treatment - empiric ABX for 7 days (hospital antibiogram to guide selection)
83
```
UTI --
risk factors
infectious agents
diagnostic evaluations
treatment
```
risk factors - indwelling foley catheters, long-stay elderly male patients, debilitated patients
infectious agents - endogenous organisms most of the time --> E. coli
diagnostic evaluation - UA and urine culture
treatment - empiric ABX and remove catheter
84
What are the risk factors for surgical wounds?
present 5-10 days after surgery
deep more common than superficial
risk factors - poor skin prep, wound contamination, age/general health, duration of surgery, the skill of the surgeon
85
Surgical wounds are most common;y caused by
S. auerus, K. pneumonia, P. aerugionsa, and E. coli
86
What are the diagnostic criteria for superficial and deep surgical wounds?
Superficial - within 30 days of operation
| Deep - within 30 days of operation or 1 year if implant in place
87
What is the recommended treatment for nosocomial infections of surgical wounds
ABX (empiric or targeted with positive culture)
wound debridement, drainage, and dressing changes
removal of implanted materials if necessary
88
What is the most common symptom associated with hospital-associated infections
Diarrhea
89
Nosocomial infections: GI infections
risk factors
diagnostic evaluations
treatment
risk factors - ABX use, >60 years, exposure to other patients with infection, underlying disease, recent surgery
diagnostic evaluation - stool cultures
treatment - prevention is best
discontinue causative ABX
IV ABX, hydration
occasionally a surgery to remove disease colon
90
What is the most common etiology of fever of unknown origin?
TB, endocarditis, gallbladder disease, HIV, etc
91
FUO from infection
```
TB, endocarditis
HIV
EBV
CMV
occult abscess
```
92
FUO from neoplasms
lymphoma
leukemia
liver and renal cancers
93
FUO from autoimmune disorders
lupus
still disease
polyarteritis nodosa
GCA, PMR in older adults
94
What is the diagnostic criteria for an FUO
fever present with no diagnosis after 3 outpatient visits or 3 days of hospitalization
