Microbiology Quiz on Brucella and Hemophilus

Hemophilus influenzae, formerly known as Pfeiffer's bacillus, is a small, gram-negative bacterium that can cause various infections. It was initially mistaken for the cause of influenza but was later determined to be a separate bacterium.

Hemophilus influenzae requires specific growth factors, X factor (hematin) and V factor (NAD). These factors are present in erythrocytes, making blood-enriched media like chocolate agar essential for its growth.

The phenomenon where Hemophilus influenzae grows around other bacteria due to the release of essential growth factors is known as satellitism.

Hemophilus influenzae is a common inhabitant of the human respiratory tract and oral cavity, but can also cause infections under certain conditions.

The capsule of Hemophilus influenzae is a protective outer layer that plays a significant role in its virulence. Certain serotypes, particularly type b, are strongly associated with severe infections.

Hemophilus influenzae is primarily transmitted through respiratory droplets or direct contact with contaminated secretions.

Hemophilus influenzae can cause various infections, including meningitis, pneumonia, epiglottitis, and otitis media. The severity of infection can vary depending on the serotype and individual factors.

Most cases of invasive Haemophilus influenzae type b (Hib) disease are caused by serotype Hib.

Hib vaccine has significantly reduced the incidence of Hib disease in areas where it's been implemented.

Hib infection spreads through direct contact with respiratory secretions from an infected person.

Only capsulated strains of Haemophilus influenzae are able to cause invasive infections, which means they can spread throughout the body.

More than 90% of invasive Haemophilus influenzae strains are type b.

Haemophilus influenzae type b (Hib) bacteria use pili and outer membrane proteins to attach to respiratory cells.

Once attached, Hib bacteria invade between cells, bypassing the body's natural defenses.

The capsule surrounding Hib bacteria helps them avoid being engulfed and destroyed by immune cells (phagocytosis).

Haemophilus influenzae type b (Hib) can cause a variety of infections including septic arthritis, osteomyelitis, cellulitis, pericarditis, pneumonia, otitis media, and meningitis.

Brucella is a genus of bacteria that can cause brucellosis, a zoonotic disease that affects animals and humans. It's known for its slow growth, requiring enriched blood agar and aerobic conditions. Interestingly, it produces catalase, oxidase, and urease but cannot ferment carbohydrates.

The pathogenic potential of Brucella relies on its ability to invade host cells and survive within them. This way, it can multiply and cause infections.

After entering the body through skin or mucous membranes, Brucella evades the immune system's first line of defense, toll-like receptors, and multiplies inside macrophages. It then forms granulomas in the liver, spleen, and bone marrow.

Acute brucellosis usually presents 1-3 weeks after infection with symptoms like fever, night sweats, muscle and joint pain, headache, and weight loss. These symptoms can persist for weeks or months.

Brucellosis can have long-term complications that affect various systems, including the musculoskeletal, gastrointestinal, genitourinary, and cardiovascular systems. Due to its mimicking nature, diagnosis and treatment can be challenging.

A serious condition affecting individuals with a compromised immune system or absent spleen function, making them highly susceptible to infections caused by Haemophilus influenzae.

Culture tests using a specialized media called chocolate agar help identify Haemophilus influenzae. The bacterium's growth on this media, but not on blood agar, suggests its presence.

Haemophilus ducrey, the causative agent of chancroid, is a fastidious, Gram-negative, facultative anaerobic coccobacilli. This means it requires specific conditions to survive and can grow with or without oxygen.

Chancroid is a sexually transmitted infection characterized by painful, necrotizing ulcers on the genitals. It can also lead to swollen lymph nodes in the groin.

Chancroid is transmitted mainly through direct contact with sores, often during sexual activity. It can also spread through autoinoculation, where the infection is transferred to other parts of the body, such as the eyes or skin.

Bordetella is a genus of bacteria known for causing respiratory infections, especially in humans. They are strict aerobes, meaning they need oxygen to survive, are Gram-negative, and have a characteristic size and shape.

Bordetella bacteria spread through respiratory droplets released when infected individuals cough or sneeze. This mode of transmission makes them highly contagious.

Bordetella primarily targets humans and does not require invasion of host tissues to cause disease.

The discovery of Bordetella pertussis, the cause of whooping cough, was attributed to Jules Bordet and Octave Gengou in 1900.

Haemophilus ducreyi is a highly contagious but treatable infection.

Brucella spp. are bacteria responsible for causing Brucellosis, a zoonotic disease affecting both animals and humans. They are gram-negative, small, coccobacilli (rod-shaped) bacteria that are aerobic, non-motile, and urease-positive. Their lack of a sugary capsule makes them distinct.

Brucella spp. are known for causing infections in a variety of animal species, including cattle, sheep, goats, pigs, and dogs.

There are eight identified species of Brucella, with six of them being capable of infecting humans.

Brucella melitensis is a species of Brucella that primarily affects sheep and goats. It possesses a high pathogenicity for humans, meaning it can cause severe illness.

Brucella abortus, commonly found in cattle, is another species of Brucella that can infect humans. While it can cause illness, it is considered to have moderate pathogenicity, meaning it's less likely to cause severe infections.

Brucella suis, primarily infecting pigs, can cause serious infections in humans. It is considered highly pathogenic, like melitensis.

Brucella canis, found in dogs, can cause infection in humans, though it's considered to have moderate pathogenicity, similar to Brucella abortus.

Brucellosis, the disease caused by Brucella spp, can be spread through various ways. These include consuming contaminated unpasteurized milk or dairy products, breathing in contaminated dust or aerosols, or having the bacteria enter open wounds.

The primary reservoir for Brucella abortus is cattle, buffalo, and camels. The bacteria have been found in these animals.

Brucellosis presents a significant occupational hazard for veterinarians, as they may be exposed to infected animals during their work.