Bacteriology
Bacteriology is the scientific study of bacteria, which are single-celled microorganisms that can be found almost everywhere on Earth. While many bacteria are harmless or even beneficial, some are pathogenic (disease-causing).
What it analyzes/detects:
Bacteria
A vast array of species (e.g., Staphylococcus aureus, Escherichia coli, Streptococcus pneumoniae, Mycobacterium tuberculosis).
Bacterial toxins
Some bacteria produce toxins that cause disease.
Common Methodologies & Tests
Culture
Growing bacteria from patient samples (e.g., blood, urine, sputum, wound swabs) on various agar plates or in liquid media to isolate and multiply them.
Gram Stain
A rapid differential stain used to classify bacteria into Gram-positive (purple) or Gram-negative (pink/red) based on their cell wall composition, aiding in initial identification.
Biochemical Tests
A series of tests that assess a bacterium's metabolic activities to identify the species (e.g., catalase, oxidase, fermentation tests).
Automated Identification Systems
Instruments that rapidly identify bacteria using pre-programmed biochemical profiles or mass spectrometry.
Antimicrobial Susceptibility Testing (AST):
Determining which antibiotics are effective against the isolated bacteria (e.g., Kirby-Bauer disk diffusion, broth microdilution, automated systems). This is crucial for guiding treatment.
Molecular Methods (e.g., PCR):
Direct detection of bacterial DNA/RNA, especially for fastidious (hard-to-grow) organisms or resistance genes.
Diagnosis of Bacterial Infections
Identifying the specific bacterial pathogen causing infections (e.g., UTIs, pneumonia, sepsis, meningitis, skin infections).
Guiding Antibiotic Therapy
Providing critical information on antibiotic susceptibility to ensure effective treatment and combat antimicrobial resistance.
Infection Control
Identifying sources of infection and tracking outbreaks within healthcare settings or the community.
Virology
Virology is the scientific study of viruses, which are obligate intracellular parasites (meaning they can only replicate inside living host cells). Viruses are responsible for a wide range of human diseases.
What it analyzes
Viruses
(e.g., Influenza virus, HIV, Hepatitis viruses, SARS-CoV-2, Herpes simplex virus, Dengue virus).
Viral antigens
Proteins produced by the virus.
Viral nucleic acids
Viral DNA or RNA.
Antibodies
Host antibodies produced in response to a viral infection.
Clinical Importance
Diagnosis of Viral Infections
Identifying the specific virus causing illnesses (e.g., common cold, flu, HIV, hepatitis, herpes, measles, COVID-19).
Monitoring Viral Load
Tracking the amount of virus in a patient's body (e.g., HIV, HBV, HCV) to assess disease progression and treatment effectiveness.
Guiding Antiviral Therapy
Identifying specific viral strains or resistance mutations to select appropriate antiviral drugs.
Public Health & Outbreak Management
Rapidly identifying emerging viruses and tracking their spread (e.g., during pandemics).
Vaccine Development & Efficacy
Assessing immune responses to vaccines.