Microbiology: Streptococcal Infections Overview

Streptococcal Infections

• Streptococcal Pharyngitis (Strep Throat)

  • Caused by Group A Streptococcus (S. pyogenes)
  • Transmitted through respiratory droplets and direct contact
  • Symptoms include sore throat, fever, swollen lymph nodes, and white patches on the tonsils
  • Treated with antibiotics, typically penicillin or amoxicillin.

• Scarlet Fever

  • Caused by the same bacteria as strep throat when a toxin is produced
  • Characterized by a red rash, high fever, and strawberry tongue
  • Transmitted through infected individuals or contaminated objects
  • Managed with antibiotics and supportive care.

• Necrotizing Fasciitis

  • Severe infection often caused by S. pyogenes
  • Rapidly destroys tissue and can lead to systemic shock
  • Transmission via skin breaks or after surgical procedures
  • Requires aggressive treatment including surgery and intravenous antibiotics.

Complications of Streptococcal Infections

• Rheumatic Fever

  • Potentially arises after untreated streptococcal throat infection
  • Affects heart, joints, skin, and nervous system
  • Can cause long-term heart damage and requires anti-inflammatory medication.

• Post-Streptococcal Glomerulonephritis

  • Kidney inflammation following streptococcal infections
  • Symptoms include hematuria and hypertension
  • Usually resolves with minimal long-term effects but requires monitoring.

• Toxic Shock Syndrome

  • Rare but life-threatening condition linked to streptococcal infections
  • Symptoms include fever, rash, and multi-organ dysfunction
  • Treatment involves immediate antibiotics and supportive care.

Upper Respiratory Infections

• Haemophilus Influenzae Infections

  • Causes conditions like otitis media and sinusitis
  • Symptoms include ear pain, fever, and nasal congestion
  • Vaccination has reduced incidence; treated with antibiotics.

• Streptococcus Pneumoniae Infections

  • Leading cause of bacterial pneumonia and sinusitis
  • Symptoms include cough, fever, chest pain, and difficulty breathing
  • Comprehensive vaccination programs have decreased prevalence; treated with appropriate antibiotics.

Causative Agents, Transmission, Signs, and Symptoms

• Whooping Cough

  • Causative agent: Bordetella pertussis
  • Transmission: airborne droplets from coughs or sneezes
  • Symptoms: severe coughing fits, respiratory distress, and vomiting
  • Treatment: antibiotics and supportive care.

• Bacterial Pneumonia

  • Causative agents: various bacteria including Streptococcus pneumoniae
  • Transmission: respiratory droplets, aspiration, or blood
  • Symptoms: cough, fever, chills, chest pain, and difficulty breathing
  • Treatment: targeted antibiotics and sometimes hospitalization.

• Tuberculosis

  • Causative agent: Mycobacterium tuberculosis
  • Transmission: airborne via inhalation of droplets from an infected person
  • Symptoms: persistent cough, fever, night sweats, and weight loss
  • Treatment: combination antibiotic therapy over an extended period.

• Legionnaire's Disease

  • Causative agent: Legionella pneumophila
  • Transmission: inhalation of aerosolized water contaminated with bacteria
  • Symptoms: high fever, cough, shortness of breath, muscle aches, and headaches
  • Treatment: antibiotics effective against Legionella and supportive care.

Rhinovirus Infection Effects

• Causes the common cold, leading to symptoms such as runny nose, sore throat, coughing, and sneezing
• Increases mucus production and inflammation in the upper respiratory tract
• Can lead to secondary infections like sinusitis or otitis media in vulnerable populations.