L.5 Neisseria spp. Flashcards
(89 cards)
1
Q
What are Gram-negative cocci?
A
Spherical-shaped bacteria that stain pink with Gram staining due to their thin peptidoglycan layer.
2
Q
Name two important families of Gram-negative cocci.
A
- Neisseriaceae
- Moraxellaceae
3
Q
What type of organisms are typically found in the Moraxellaceae family?
A
Generally consists of commensal organisms, rarely pathogenic.
4
Q
What is the genus of Gram-negative cocci that is clinically important?
A
Neisseria
5
Q
Describe the morphology of Neisseria.
A
Gram-negative diplococci that appear as pairs of kidney- or coffee bean-shaped cells.
6
Q
What are the characteristics of Neisseria bacteria?
A
- Non-motile
- Non-spore forming
- Oxidase positive
- Aerobic
7
Q
How many known species of Neisseria are human colonisers?
A
11 known species
8
Q
Which species of Neisseria causes gonorrhea?
A
Neisseria gonorrhoeae
9
Q
Which species of Neisseria is responsible for meningitis and meningococcemia?
A
Neisseria meningitidis
10
Q
What is a non-pathogenic commensal species of Neisseria?
A
N. lactamica
11
Q
What is the appearance of Neisseria meningitidis under a microscope?
A
Typically observed in pairs with flattened adjacent sides (coffee bean appearance).
12
Q
What type of bacteria is Neisseria meningitidis?
A
Gram-negative diplococcus
13
Q
What is the transmission method for Neisseria meningitidis?
A
Via respiratory droplets (sneezing, coughing, kissing).
14
Q
What percentage of the population carries Neisseria meningitidis asymptomatically?
A
~10–15%
15
Q
Name some high-risk environments for Neisseria meningitidis infection.
A
- Nurseries
- Schools
- Military barracks
16
Q
True or False: Neisseria meningitidis is motile.
A
False
17
Q
Fill in the blank: Neisseria meningitidis is an _______.
A
obligate aerobe
18
Q
What is the function of the polysaccharide capsule in pathogenesis?
A
Inhibits phagocytosis; key for survival in the bloodstream. Also used for serogroup classification (A, B, C, Y, W-135).
19
Q
What is the role of pili (fimbriae) in bacterial virulence?
A
Mediate initial adhesion to nasopharyngeal epithelial cells. Essential for colonization.
20
Q
What do Opa and Opc proteins do?
A
Aid in tighter adhesion to host cells and invasion across mucosal surfaces.
21
Q
What is the function of IgA protease?
A
Destroys secretory IgA, helping bacteria evade mucosal immunity.
22
Q
What does catalase do in the context of bacterial survival?
A
Breaks down reactive oxygen species like H₂O₂, enabling survival inside neutrophils.
23
Q
What is the role of factor H binding protein in evading immunity?
A
Binds factor H (a regulatory protein of complement), downregulates complement activation, and allows evasion of innate immunity.
24
Q
What is lipooligosaccharide (LOS) similar to in Gram-negative bacteria?
A
Similar to LPS in Gram-negatives. Triggers a strong inflammatory response → fever, hypotension, DIC.
25
Fill in the blank: The polysaccharide capsule is key for _______ in the bloodstream.
survival
26
True or False: Pili are not essential for bacterial colonization.
False
27
What is meningococcemia?
A rapid bloodstream infection.
## Footnote
Symptoms include fever, purpuric rash, hypotension, and multi-organ failure.
28
What are the complications of meningococcemia?
Disseminated intravascular coagulation (DIC) and shock.
## Footnote
Mortality can be up to 50% if untreated.
29
What triggers disseminated intravascular coagulation (DIC)?
Endothelial damage from LOS.
## Footnote
This leads to widespread clotting and depletion of clotting factors, resulting in bleeding.
30
What syndrome may result from adrenal gland involvement in DIC?
Waterhouse-Friderichsen Syndrome.
## Footnote
This syndrome is characterized by hemorrhagic necrosis, adrenal failure, and death.
31
How does meningitis occur?
The organism crosses the blood-brain barrier via endothelial disruption.
## Footnote
Symptoms include sudden onset of fever, headache, stiff neck, vomiting, photophobia, and petechial rash.
32
What is the mortality rate of meningitis even with treatment?
5–15%.
## Footnote
Long-term sequelae include hearing loss and cognitive deficits in 10–15% of survivors.
33
What is the most common form of bacterial meningitis in Ireland?
Invasive meningococcal disease (IMD).
## Footnote
Approximately 31 cases are reported annually in Ireland.
34
How many deaths occur annually due to invasive meningococcal disease in Ireland?
Approximately 5 deaths.
## Footnote
The highest incidence is observed in infants under 1 year old.
35
What serogroups of meningococcal disease are identified?
A, B, C, Y, W-135.
## Footnote
Serogroup B is the most common in recent years.
36
Fill in the blank: The mortality rate of untreated meningococcemia can be up to _______.
50%.
37
True or False: The highest incidence of invasive meningococcal disease in Ireland occurs in adults.
False.
## Footnote
The highest incidence occurs in infants under 1 year old.
38
What vaccine was introduced in 2000?
MenC (serogroup C) vaccine
## Footnote
The MenC vaccine targets serogroup C meningococcal disease.
39
What vaccine was introduced for infants in 2016?
MenB vaccine
## Footnote
The MenB vaccine provides protection against serogroup B meningococcal disease.
40
What vaccine was introduced in 2019 for broader protection?
MenACWY conjugate vaccine
## Footnote
This vaccine covers serogroups A, C, W, and Y.
41
What types of samples are collected for laboratory diagnosis?
Blood, CSF
## Footnote
CSF stands for cerebrospinal fluid.
42
What is observed in microscopy for Neisseria meningitidis?
Gram-negative diplococci in CSF
## Footnote
These can be found intracellularly.
43
What type of culture media is used for Neisseria meningitidis?
Chocolate agar, Thayer-Martin selective media
## Footnote
These media are used to grow fastidious organisms.
44
What is PCR useful for in the context of Neisseria meningitidis?
Partially treated or culture-negative cases
## Footnote
PCR can help detect the bacteria when cultures fail.
45
What is serogrouping used for?
Public health and vaccine coverage
## Footnote
It helps in understanding the prevalence of different serogroups.
46
What is antigen detection in laboratory diagnosis?
Rapid but less sensitive than PCR
## Footnote
Antigen detection tests can quickly identify the presence of bacteria.
47
What is the empirical therapy for Neisseria meningitidis infection?
IV ceftriaxone or penicillin
## Footnote
These are commonly used antibiotics for treatment.
48
What type of care is provided alongside treatment?
Supportive care: Fluids, vasopressors, intensive care
## Footnote
Supportive care is crucial for managing severe cases.
49
What prophylaxis is recommended for contacts of Neisseria meningitidis?
Rifampicin or ciprofloxacin
## Footnote
These antibiotics help prevent the spread of infection.
50
What type of organism is Neisseria gonorrhoeae?
Gram-negative diplococcus
## Footnote
It is responsible for the sexually transmitted infection gonorrhoea.
51
Is Neisseria gonorrhoeae part of normal human flora?
No
## Footnote
Unlike other Neisseria species, it does not inhabit the human body normally.
52
How is Neisseria gonorrhoeae primarily transmitted?
Sexual contact
## Footnote
This includes vaginal, anal, and oral routes.
53
What is the epidemiological trend of gonorrhoea globally?
Highly prevalent, especially in sexually active young adults
## Footnote
Infections often go unnoticed, particularly in females.
54
What is a significant concern in the treatment of gonorrhoea?
Antimicrobial resistance (AMR)
## Footnote
AMR complicates effective treatment strategies.
55
What was the percentage increase in gonorrhoea notification rates in Ireland from 2019 to 2023?
125% increase
## Footnote
This indicates a significant rise in reported cases.
56
What was the increase in gonorrhoea notifications among males?
107% increase
## Footnote
The median age for males affected is 30 years.
57
What was the increase in gonorrhoea notifications among females?
217% increase
## Footnote
The median age for females affected is 22 years.
58
What percentage of total gonorrhoea notifications were from HSE home STI testing services in 2023?
25%
## Footnote
This highlights the role of home testing in identifying cases.
59
What are virulence factors?
Molecules produced by pathogens that contribute to their ability to cause disease
## Footnote
Virulence factors enhance the pathogenicity of microorganisms.
60
What is the function of pili (fimbriae)?
Enable attachment to host mucosal epithelium and play a role in horizontal gene transfer, including AMR gene exchange
## Footnote
Pili are hair-like structures on the surface of bacteria that facilitate adhesion.
61
What is antigenic variation?
Surface proteins, including pili and Opa proteins, undergo variation, evading immune detection and complicating vaccine development
## Footnote
This mechanism helps pathogens avoid the host immune system.
62
What is the role of IgA protease?
Cleaves secretory IgA in mucosal secretions, helping bacteria evade local immunity
## Footnote
IgA is an antibody that plays a crucial role in mucosal immunity.
63
What is the function of catalase in bacteria?
Breaks down reactive oxygen species, allowing survival inside neutrophils
## Footnote
Catalase helps bacteria withstand oxidative stress from the immune system.
64
True or False: The bacterium lacks a polysaccharide capsule.
True
## Footnote
This distinguishes it from N. meningitidis, which has a capsule.
65
What is the most common symptom of urethritis in men?
Dysuria and purulent (yellow) urethral discharge
## Footnote
Symptoms appear 1–14 days post-infection.
66
What infections are common in men who have sex with men (MSM)?
Anorectal and oropharyngeal infections
## Footnote
Asymptomatic infections are less common in males.
67
What percentage of women with gonorrhea are often asymptomatic?
50–85%
## Footnote
This makes women a significant reservoir of infection.
68
When symptomatic, what areas do gonorrhea infections typically involve in women?
Cervix and vagina
## Footnote
Infections may ascend to cause complications.
69
What are potential complications of ascending gonorrhea infections in women?
* Pelvic Inflammatory Disease (PID)
* Infertility
* Ectopic pregnancy
* Fitz-Hugh–Curtis syndrome
## Footnote
Fitz-Hugh–Curtis syndrome involves perihepatic inflammation with adhesions.
70
What is a common symptom of anorectal gonorrhea?
Proctitis (rectal inflammation)
## Footnote
Often asymptomatic, especially in females.
71
How is pharyngeal infection typically diagnosed?
Through screening (e.g., throat swabs)
## Footnote
Common in individuals with orogenital contact and often asymptomatic.
72
What is neonatal conjunctivitis and how is it transmitted?
Ophthalmia neonatorum, transmitted during vaginal delivery
## Footnote
Appears 2–5 days post-birth.
73
What is Disseminated Gonococcal Infection (DGI)?
A rare condition where bacteria spread systemically
## Footnote
Leads to arthritis-dermatitis syndrome and endocarditis.
74
What types of specimens are collected for laboratory diagnosis of gonorrhea?
* Urethral (men)
* Cervical (women)
* Pharyngeal
* Rectal
* Occasionally joint aspirate
## Footnote
N. gonorrhoeae is fastidious, requiring rapid transport using specialized media.
75
What is the sensitivity of Gram stain microscopy for symptomatic males?
~90%
## Footnote
Only ~30% sensitivity in asymptomatic cases and in females.
76
What enriched media is required for culturing N. gonorrhoeae?
* Thayer-Martin agar
* New York City medium
## Footnote
Thayer-Martin agar is chocolate agar with antibiotics.
77
What are the incubation requirements for culturing N. gonorrhoeae?
* 37°C incubation
* 5–10% CO₂ atmosphere
* 24–48 hours for visible growth
## Footnote
N. gonorrhoeae is more fastidious than N. meningitidis.
78
What type of bacteria are Gram-negative diplococci?
N. gonorrhoeae and N. meningitidis
## Footnote
These are common pathogens associated with human infections.
79
What are the characteristics of the bacteria mentioned?
Oxidase-positive, catalase-positive, non-motile, aerobic
## Footnote
These characteristics help in the presumptive identification of these bacteria.
80
What is the carbohydrate utilization profile for N. gonorrhoeae?
Glucose (+), Maltose (–), Lactose (–), Sucrose (–)
## Footnote
This profile is crucial for differentiating N. gonorrhoeae from other species.
81
What is the carbohydrate utilization profile for N. meningitidis?
Glucose (+), Maltose (+), Lactose (–), Sucrose (–)
## Footnote
This profile indicates its ability to utilize maltose.
82
What is the carbohydrate utilization profile for N. lactamica?
Glucose (+), Maltose (+), Lactose (+), Sucrose (–)
## Footnote
This profile shows that N. lactamica can ferment lactose.
83
What are MALDI-TOF MS and VITEK-NH used for?
Automated identification systems
## Footnote
These systems help in the rapid identification of bacteria.
84
What is the gold standard molecular testing method for detecting N. gonorrhoeae?
PCR
## Footnote
PCR directly detects DNA from clinical specimens.
85
What does PCR allow for in terms of detection?
Simultaneous detection of N. gonorrhoeae and Chlamydia trachomatis
## Footnote
This is particularly useful for diagnosing co-infections.
86
What factors make PCR especially important?
High sensitivity and specificity, especially in asymptomatic patients and non-genital sites
## Footnote
These factors improve the accuracy of diagnosis.
87
What is the current first-line therapy for treating infections caused by N. gonorrhoeae?
Dual treatment with ceftriaxone + doxycycline/azithromycin
## Footnote
This approach helps combat rising antibiotic resistance.
88
True or False: There is rising antibiotic resistance in N. gonorrhoeae.
True
## Footnote
Resistance has been observed against fluoroquinolones, penicillin, and cephalosporins.
89
Why is ongoing surveillance of resistance patterns essential?
To monitor and respond to rising antibiotic resistance
## Footnote
Surveillance can be conducted through programs like GISP/Euro-GASP.
