Category: Bacteriology

STREPTOCOCCUS PNEUMONIAE

Streptococcus pneumoniae, prevalent in the human upper respiratory tract, causes various infections including pneumonia, often in vulnerable individuals. Its virulence is linked to its polysaccharide capsule, interfering with phagocytosis. Early detection and treatment with appropriate antibiotics and preventive vaccination are vital, especially for high-risk groups like the elderly and immunocompromised individuals.

SHIGELLA DYSENTERIAE

Shigella dysenteriae is a Gram-negative, non-motile bacterium causing bacillary dysentery. It’s transmitted primarily through the fecal-oral route, requiring a low dose to initiate infection. Symptoms include bloody diarrhea and abdominal cramps. Diagnosis involves stool cultures, and treatment may include antibiotics for severe cases. Prevention focuses on hygiene and clean water.

TREPONEMA PALLIDUM

Treponema pallidum, a Gram-negative spirochaete, causes syphilis, a contagious STD spread through direct contact, including mother-to-child transmission. The disease progresses through primary, secondary, and tertiary stages without treatment, potentially causing severe complications. Laboratory diagnosis relies on serological tests, as the bacterium cannot be cultured in vitro. Prevention includes safe sexual practices and treating infected individuals.

Helicobacter pylori

Helicobacter pylori is a spiral-shaped bacterium causing peptic and gastric ulcers, linked to stomach cancer. It survives stomach acidity by producing urease, creating an alkaline environment. Spread via fecal-oral route, it induces inflammation in the gastric mucosa. Diagnosis involves invasive and non-invasive tests, treatment includes antibiotics and protein-pump inhibitors. Prevention focuses on hygiene.

SALMONELLA (S. TYPHI)

Salmonella Typhi, a Gram-negative rod, causes typhoid fever in humans, transmitted through contaminated food and water. Non-typhoid strains, like S. Typhimurium, cause gastrointestinal infections. Infections primarily spread via the fecal-oral route, and effective prevention includes good hygiene, proper food handling, and clean water. Treatment involves antibiotics and hydration.

RICKETTSIA PROWAZEKII

Rickettsia prowazekii is an obligate intracellular parasite causing epidemic typhus, primarily transmitted via lice bites. Symptoms include vasculitis, thrombosis, and systemic infections. Diagnosis involves serological tests and cell culture. Treatment includes chloramphenicol and tetracyclines; prevention focuses on vector control and hygiene. RMSF and Q fever are related rickettsial diseases.

STREPTOCOCCUS PYOGENES

Streptococcus pyogenes, a Group A Streptococcus, is a Gram-positive bacterium causing pharyngitis and various streptococcal diseases like scarlet fever, cellulitis, and necrotizing fasciitis. It produces numerous virulence factors including streptolysins and exotoxins. Diagnosis involves cultural, microscopic, and serological tests. Treatment includes antibiotics like penicillin, and no vaccines exist currently.

STAPHYLOCOCCUS AUREUS

Staphylococcus aureus, a Gram-positive bacterium, is often found in the nose and skin of humans. It causes various infections including pneumonia, gastroenteritis, and toxic shock syndrome, aided by its production of toxins and enzymes. Resistant strains like MRSA are prevalent. Prevention relies on hygiene practices, as vaccines are unavailable.

PROTEUS MIRABILIS

Proteus mirabilis is a Gram-negative, motile, non-capsulated, facultative anaerobic, non-lactose fermenting and pleomorphic bacillus in […]

ESCHERICHIA COLI

Escherichia coli is a facultative, enteric, Gram-negative, motile/flagellated, and lactose-fermenting rod that occur in the […]

CLOSTRIDIUM BOTULINUM

Clostridium botulinum is a Gram-positive, strict-anaerobic, motile, pleomorphic, catalase-negative, endospore-forming bacillus (rod) that is ubiquitously […]

VIBRIO CHOLERAE

Vibrio cholerae is a Gram-negative, oxidase positive, spiral, non-spore forming, facultative, motile, curved or straight […]

NEISSERIA GONORRHOEAE

Neisseria gonorrhoeae is a Gram-negative, oxidase-positive, non-motile, non-sporulating, non-capsulate, diplococcus found asymptomatically in humans. N. […]

Bacillus anthracis

Bacillus anthracis is a mesophilic, Gram-positive, aerobic, catalase-positive, rod-like and spore-forming bacterium that causes anthrax […]