23 - 154 - GRAN-NEGATIVE COCCAL AND BACILLARY INFECTIONS

Question 1

The single most important factor in the treatment of acute meningococcal infection

Answer 1

early initiation of antibiotics

Ideally, no more than 30 minutes should pass between a presumptive diagnosis and administration of intravenous therapy.

Question 2

N. meningitidis serogroups that cause life-threatening disease

Answer 2

A, B, C, W-135, X, and Y

Question 3

hallmark of Acute meningococcemia

Answer 3

petechial rash

When present, petechiae are** small and irregular with a “smudged” appearance,** and may occur all over the body, including palms, soles, mucous membranes, and conjunctiva, although the extremities are the most common location

Question 4

may occur with severe disseminated intravascular coagulation (DIC) caused by sepsis, characterized by retiform purpura and necrosis of the skin, which may extend to subcutaneous tissues and, occasionally, muscle and bone

Answer 4

Purpura fulminans

Question 5

• characterized by polymorphous cutaneous lesions, and may fade and recur with intermittent fevers
• Skin findings often occur around painful joints or pressure points

Answer 5

chronic meningococcemia

Question 6

most common skin findings of chronic meningococcemia

Answer 6

rose-colored macules and papules

Question 7

life-threatening condition characterized by adrenal hemorrhage and ensuing adrenal crisis, often accompanied by purpura fulminans

Answer 7

Waterhouse-Friderichsen syndrome

Question 8

With breach of the blood–brain barrier, patients may develop this condition, which is marked by meningism (nuchal rigidity, headache, photophobia), fever, nausea/vomiting, and altered mental status. Kernig and Brudzinski signs may become positive

Answer 8

meningococcal meningitis

Question 9

can occur while patients are in recovery, which may include a range of symptoms due to sterile arthritis, vasculitis, pleuritis, pericarditis, or episcleritis

Answer 9

delayed immune complex-mediated syndrome

Question 10

the most common sequela of meningitis

Answer 10

sensorineural hearing loss or deafness

Question 11

N. meningitidis is known to reside in what part of the body?

What is the mode of transmission?

Answer 11

nasopharynx of healthy individuals, and can be transferred from person to person via respiratory droplets or by direct contact, such as kissing

Question 12

The single greatest risk factor for disseminated meningococcal disease

Answer 12

lack of bactericidal antibodies

Question 13

Prior to obtaining antibiotic sensitivity results, patients with meningococcemia should be treated with what antibiotic?

Answer 13

third-generation cephalosporin such as ceftriaxone or cefotaxime

Question 14

For patients with meningococcemia, If testing reveals a penicillin minimum inhibitory concentration less than 0.1 µg/mL, what medications should be given?

Answer 14

penicillin G or ampicillin

Question 15

For patients who are allergic to penicillin and cephalosporin, what is an alternative medication?

Answer 15

chloramphenicol

Question 16

Although not widely available, patients with purpura fulminans may benefit from what?

Answer 16

protein C concentrate

Question 17

Fill in the blanks

Close contacts are defined as those who have had prolonged contact (>____ hours) within close proximity (<____ feet) of an infected patient, or those who have had direct exposure to the patient’s oral secretions from ____ days before the onset of symptoms until ___ hours following initiation of effective antibiotics

Answer 17

Close contacts are defined as those who have had prolonged contact (>8 hours) within close proximity** (<3 feet) **of an infected patient, or those who have had direct exposure to the patient’s oral secretions from 7 days before the onset of symptoms until **24 hours **following initiation of effective antibiotics

Question 18

Antibiotics recommended for chemoprophylaxis for meningococcal disease

Answer 18

• rifampin (children and adults; 4 doses given over 2 days)
• ciprofloxacin (adults; single dose), and
• ceftriaxone (children, adults, and pregnant women; single intramuscular dose)

Question 18

In ideal situations, chemoprophylaxis of meningococcal disease in those meeting criteria should be initiated within how many hours of identification of an index patient?

Answer 18

24 hours

Question 19

schedule of meningococal vaccination

Answer 19

Ideally, patients should be vaccinated at 11 or 12 years old with a booster at age 16 years

Question 20

pigment produced by P. aeruginosa

Answer 20

pyocyanin and pyoverdin pigment

• P. aeruginosa produces pyoverdin, a green-yellow pigment that fluoresces under a Wood lamp and is common to all fluorescent Pseudomonas species.
• It also produces pyocyanin, a** blue-green** nonfluorescent pigment specific to P. aeruginosa

Question 21

a green-yellow pigment that fluoresces under a Wood lamp and is common to all fluorescent Pseudomonas species

Answer 21

pyoverdin

Question 22

blue-green nonfluorescent pigment specific to P. aeruginosa.

Answer 22

pyocyanin

Question 23

characterized by nail dyspigmentation that may be greenish-yellow, greenish-blue, greenish-brown, or greenish-black.

Answer 23

Green nail syndrome, or chloronychia

• Dyspigmentation results from the accumulation of debris and pyocyanin, which adheres to the underside of the nail plate
• Many patients present with a triad of dyspigmentation, onycholysis, and paronychia

Question 24

presents with thickened, macerated skin with a characteristic moth-eaten appearance and yellow-green purulence

Answer 24

P. aeruginosa toe web infection

Question 25

* presents with discrete, follicular papules and pustules that heal with fine desquamation and hyperpigmented macules. * Onset is sudden, approximately 24 hours following exposure to contaminated hot tubs or whirlpools and may be associated with pruritus or pain.

Answer 25

P. aeruginosa folliculitis, commonly “hot tub folliculitis,”

Question 26

* develops following emersion in contaminated wading pools and hot tubs, usually in children * It presents with acute painful, erythematous, warm plantar nodules.

Answer 26

hot-foot syndrome

Question 27

* characterized by acute onset of edema and erythema or discoloration of the external auditory canal, sometimes with maceration, discharge and/or regional lymphadenopathy. * There is often tenderness with tragal pressure or movement of the pinna, and patients may complain of pruritus

Answer 27

Otitis externa, or “swimmer’s ear,”

Question 28

* In elderly patients, especially those with diabetes, external otitis may progress to what invasive condition leading to **skull-base osteomyelitis**? * characterized by an **insidious onset with edema, erythema, and persistent discharge** from the ear canal with **severe pain** that appears disproportionate to examination findings. * Early cases usually **lack fever or constitutional symptoms.** * The presence of **granulation tissue** in the floor of the external auditory canal at the bony–cartilaginous junction is a classic finding, and frank **necrosis** of the canal also may be present. * Tympanic membrane visualization is often blocked by discharge and granulation tissue

Answer 28

malignant otitis externa

Question 29

* may be caused by P. aeruginosa following commercial piercings as a result of contaminated cleansing agents, as well as following trauma or acupuncture * The ear is typically swollen, erythematous, and tender, and prompt treatment is essential because of rapid progression to cartilage necrosis.

Answer 29

Perichondritis of the ear helix or tragus

Question 29

Question 30

* responsible for **necrotic** cutaneous lesions associated with P. aeruginosa bacteremia, especially in neutropenic patients, although, rarely, bacteremia may be absent * It begins with a painless, **infarcted gunmetal gray macule or papule** with surrounding erythema. * As the it develops, the lesion becomes more **indurated and pustules or hemorrhagic bullae **may develop. * Over a rapid course of 12 to 18 hours the patient is left with a necrotic, ulcerative eschar with a halo of tender erythema * lesions most commonly affecting the **anogenital region **(57%), extremities (30%), trunk (6%), and face (6%)

Answer 30

Ecthyma gangrenosum

Question 31

Folliculitis outbreaks most commonly occur following submersion in water heated above ___°C, as P. aeruginosa is heat tolerant, and infection risk increases with duration of bathing

Answer 31

38

Question 32

The most frequent P. aeruginosa serotype isolated from pseudomonal folliculitis

Answer 32

O-11

Question 33

systemic treatment of P. aeruginosa infection

Answer 33

* penicillins (ticarcillin-clavulanic acid, piperacillin-tazobactam), * cephalosporins (cefepime, ceftazidime, cefoperazone), * monobactams (aztreonam), * carbapenems (meropenem, doripenem, imipenem/cilastatin), * fluoroquinolones (ciprofloxacin, levofloxacin), * aminoglycosides (gentamicin, tobramycin, amikacin), * polymyxins (colistin)

Question 34

Topical antimicrobials for green nail syndrome

Answer 34

* 2% sodium hypochlorite, * aminoglycosides (eg, tobramycin, gentamicin), * fluoroquinolones (eg, ciprofloxacin, nadifloxacin), * polymyxin B, or * bacitracin * Application of Castellani (carbol-fuchsin) paint, gentian violet, or acetic acid soaks also may be employed.

Question 35

Bartonella are facultative intracellular Gram-negative bacilli, that parasitize what cells?

Answer 35

erythrocytes

Question 36

1. responsible for cat scratch disease, bacillary angiomatosis, and endocarditis 2. What is the vector? 3. What is the reservoir host?

Answer 36

1. Bartonella henselae 2. cat flea (Ctenocephalides felis) 3. cats

Question 37

1. causes trench fever, bacillary angiomatosis, and endocarditis 2. Vector 3. Reservoir Host

Answer 37

1. Bartonella quintana 2. human body louse (Pediculus humanus) 3. Humans

Question 38

1. etiologic agent of Carrion disease, a biphasic infection with an acute phase known as Oroya fever, followed by a chronic phase, verruga peruana 2. Vector 3. Reservoir host

Answer 38

1. Bartonella bacilliformis 2. sand fly (Lutzomyia verrucarum) 3. Humans

Question 39

the most common Bartonella infection

Answer 39

CAT SCRATCH DISEASE

Question 40

Answer 40

Cat scratch disease (CSD)

Question 41

Answer 41

Trench fever

Question 42

Answer 42

Bacillary angiomatosis

Question 43

Answer 43

Carrion disease

Question 44

frequently the presenting sign of cat scratch disease

Answer 44

Regional lymphadenitis

Question 45

* It is characterized by cyclic fevers of approximately 5 days’ duration, and as many as 90% of patients may develop crops of erythematous macules or papules, which may be found across the abdomen, chest, and back

Answer 45

Trench Fever

Question 46

stains used to visualize Bartonella organisms

Answer 46

Warthin-Starry or Giemsa ## Footnote Bartonella organisms, which may be found as intracellular inclusions, as well as free organisms in the extracellular matrix

Question 47

classic cutaneous manifestation of enteric fever

Answer 47

rose spots

Question 48

aside from enteric fever, rose spots can also be seen in what conditions?

Answer 48

rose spots may be seen to a lesser extent in** psittacosis, leptospirosis, brucellosis, rat-bite fever, and shigellosis**

Question 49

most serious complication of enteric fever

Answer 49

intestinal perforation

Question 50

Salmonella carriage confers an increased risk of what carcinoma?

Answer 50

gallbladder carcinoma

Question 51

rhinoscleroma etiologic agent

Answer 51

Klebsiella rhinoscleromatis

Question 52

1. large vacuolated histiocytes containing K. rhinoscleromatis 2. stain to visualize these cells

Answer 52

1. Mikulicz cells 2. CD68 ## Footnote Mikulicz cells can be visualized with CD68 immunostaining, and WarthinStarry silver stain may show K. rhinoscleromatis residing in Mikulicz cells

Question 53

Biopsied tissue reveals plasma cells, lymphocytes, Russell bodies, and pathognomonic Mikulicz cells

Answer 53

Rhinoscleroma

Question 54

Stain that can be used to enhance Russell bodies

Answer 54

Periodic acid–Schiff staining

Question 55

Haemophilus influenzae is a fastidious, Gram-negative coccobacillus that grows on chocolate agar and requires what substances for growth?

Answer 55

hemin (factor X) and nicotinamide adenine dinucleotide (factor V)