Bordetella pertussis & Moraxella catarrhalis

What is the Gram stain and morphology of Bordetella pertussis?

Gram-negative nonmotile coccobacillus.

Which Bordetella species causes a milder form of bronchitis?

Bordetella parapertussis.

Which Bordetella species is a causative agent in pigs and cats but can affect immunocompromised humans?

Bordetella bronchioseptica.

What are the primary biochemical characteristics of Bordetella pertussis?

Obligately aerobic, encapsulated, oxidase positive, and catalase positive.

What is the primary mode of transmission for Bordetella pertussis?

Inhalation of droplets from coughing or sneezing.

What is the typical incubation period for pertussis?

5 to 10 days (maximum 21 days).

What is the attack rate of pertussis in susceptible individuals?

80% to 100%.

Which period of pertussis is the most contagious?

The catarrhal period and the first two weeks after cough onset.

Does transplacental transmission of maternal antibodies protect newborns from pertussis?

No, maternal antibodies do not protect the newborn.

Which Bordetella virulence factor provides attachment to ciliated respiratory epithelium?

Filamentous hemagglutinins (Fha) and pilus.

What is the function of Tracheal cytotoxin in pertussis pathogenesis?

It paralyzes the respiratory epithelium and cilia, leading to inflammatory exudate and small airway obstruction.

What is the metabolic effect of Adenylate cyclase toxin in Bordetella pertussis?

It increases cAMP, interferes with phagocytosis, and causes edema.

Which virulence factor is specifically responsible for the paroxysmal cough in pertussis?

Pertussis toxin (PT).

How does Pertussis toxin cause lymphocytosis?

It inhibits chemokine receptors, preventing lymphocytes from leaving the bloodstream to locate the infection.

What are the three clinical stages of symptomatic pertussis?

Catarrhal period, Paroxysmal period, and Convalescent period.

What clinical symptoms characterize the catarrhal period of pertussis?

Runny nose, sneezing, mild fever, conjunctivitis, and mild cough (similar to common cold).

What is the duration of the paroxysmal period in pertussis?

Usually 2 to 4 weeks, but can last up to 10 weeks.

What is the characteristic sound heard at the end of a pertussis coughing attack?

A typical high-pitched "whoop" or scream.

What are common complications of coughing seizures in infants with pertussis?

Cyanosis, post-tussive vomiting, hypoxia, and convulsions.

What is the "100-Day Cough"?

A term for pertussis, often seen in children under 2 years of age.

Which culture media are used for the definitive diagnosis of Bordetella pertussis?

Bordet-Gengou (potato-glycerol-blood agar) or Regan-Lowe agar.

Why should cotton swabs be avoided when collecting samples for Bordetella?

Cotton inhibits the growth of B. pertussis; dacron or calcium alginate swabs should be used.

What is the first-choice antibiotic treatment for pertussis?

Macrolides (used for 14 days).

What does the DTaP-IPA-Hib vaccine protect against?

Diphtheria, tetanus, pertussis, polio, and Hib meningitis.

What is the Gram stain and morphology of Moraxella catarrhalis?

Gram-negative diplococci.

How can Moraxella catarrhalis be biochemically distinguished from Neisseria meningitidis?

Moraxella is maltose negative, DNase positive, and hydrolyzes tributyrin.

What clinical condition does Moraxella catarrhalis commonly cause in adults with COPD?

COPD exacerbations and lower respiratory tract infections.

What are common infections caused by Moraxella catarrhalis in children?

Otitis media, sinusitis, bronchitis, and laryngitis.

Which antibiotic combination is typically used for Moraxella catarrhalis infections?

Amoxicillin-clavulanate or TMP-SMX.