Transcription
Asalam alikum everybody. Today we'll be looking at Campa G9. But before getting into the video, I'd like to tell you guys that these videos are meant for educational purposes. Things and treatments may change with time. If I get wrong or miss anything, your input is always welcomed in the comment section. Grab a pen and a notepad, and let's get started.
Campa jjai. It's a gram-negative rod. It has got two words in it. Both are Greek words. The first one is campelo, that is from Greek Campos, that means curved. And the second one baa, that's from Greek berron, which means rod. So this bacterium is curved in rod shape.
Campylobacter is microaerophilic. It means that it grows best in 5% oxygen rather than in 20% in the atmosphere. It is a flagellated bacterium, which makes it immortal. It belongs to the Campylobacter family and is the antecedent of Guillain-Barré syndrome. As in this picture, you can see this s-shaped, curved-shaped, rod-shaped Campylobacter jejuni.
Campylobacter jejuni is responsible for causing campylobacteriosis. That's just a broader term that any infection caused by this bacterium will be this one. But it actually causes enterocolitis, diarrhea. But if this infection becomes a systemic infection, it is bacteremia.
Campylobacter jejuni is oxidase-positive. It is non-fermenting, which means it does not ferment lactose or glucose. It grows better in 5% oxygen and grows well in 42°C temperature. It is sensitive to nalidixic acid.
We've got two species of Campylobacter. The one we're discussing in today's video, the Campylobacter jejuni, and the other one, Campylobacter intestinalis. But before talking about Campylobacter jejuni in detail, we should know how the bacteria are classified.
Bacteria are classified into spirochetes, acid-fast based on acid-fast staining, and there's an exception that a mycoplasma bacteria. And also bacteria are classified based on Gram staining into Gram-positive. We are done with all the Gram-positive bacteria. If you guys are interested, be sure to check out the channel. And bacteria also classified into Gram-negative.
Gram-negative are further subdivided into cocci, which is Neisseria. The Neisseria gonorrhoeae and Neisseria meningitidis. And rods, which include aerobic like Pseudomonas, anaerobic like Bacteroides, and facultative. Facultative is further subdivided into curved, which includes Campylobacter, the topic of today's video, Helicobacter, and Vibrio cholerae. I've got videos on them, be sure to check them out.
And also the facultative is further subdivided into straight, which is further subclassified as respiratory like Haemophilus, Bordetella, Legionella. Also as zoonotic, which includes Brucella, Francisella, Pasteurella, and Yersinia. And also enteric and related, which includes E. coli, Enterobacter, Serratia, Klebsiella, Salmonella, Shigella, and Proteus.
But that's not all. Gram-negative bacteria are further subdivided based on different shapes into diplococci, coccobacilli, rods, and comma-shaped. Diplococci are further subdivided based on maltose fermentation. If a bacterium ferments maltose, it's Neisseria meningitidis. And if it doesn't, it's Neisseria gonorrhoeae. Coccobacilli include Haemophilus influenzae, Brucella, Pasteurella, Bordetella pertussis.
Rods are further subdivided based on lactose fermentation. If bacteria ferment lactose, that are going to be fast or slow fermenters. Fast ones include Klebsiella, E. coli, and Enterobacter. And slow ones include Citrobacter and others. And non-lactose fermenters are further subdivided based on oxidase test. If a bacterium is oxidase-positive, it's Pseudomonas. And if it's oxidase-negative, it's Shigella, Salmonella, Proteus, Yersinia.
Comma-shaped bacteria are further subdivided based on certain criteria. Like if a bacteria produces urease, it's Helicobacter pylori. If it grows in alkaline media, it's Vibrio cholerae. And if it grows in 42°C temperature, it's Campylobacter jejuni.
Lecture outline. We are done with the introduction and classification. Now we'll be looking at morphology, habitat, transmission, pathogenesis, clinical findings, lab diagnosis, treatment, prevention. And at the end, as usual, we'll review the lecture.
Morphology. Campylobacter bacilli are curved Gram-negative rods that appear either comma or as s-shaped. There's an exception like these bacterium. The Campylobacter species become coccoid when they're exposed to certain conditions, like exposed to atmospheric conditions. Campylobacter jejuni varies in size from 0.5 to 5 micrometers by 2 to 9 micrometers. It is pink colored. The reason is it's Gram-negative. As in this picture, you can see the curved, comma-shaped Campylobacter jejuni.
Campylobacter is an encapsulated bacterium. It is not responsible for forming spores. It is motile, the reason is it has got a flagella. It produces certain toxins, the enterotoxins and cytotoxins. This is how Campylobacter jejuni looks like under the microscope: s-shaped, curved, comma-shaped, and rod bacterium.
Habitat. Humans are its definitive host. The reason is it causes infection in humans' small and large intestines. Domestic animals such as cattle, chickens, and dogs serve as a source of the organism for humans.
Transmission. Transmission is usually fecal-oral. And also by consuming water and food contaminated with animal feces. And consuming food like poultry and meat that's undercooked or unpasteurized milk. There are two types of transmission. Number one, human-to-human, that's less frequent. And animal-to-human.
Pathogenesis. Campylobacter jejuni uses proteases. These are the enzymes to disrupt cell junctions. The membrane-bound protein fibronectin is the binding site for Campylobacter jejuni. The critical binding site. Once inside the epithelial cells, the Campylobacter jejuni leverages dynamin to this is the protein to access the paraneuclear space within clathrin-coated vesicles. This allows the bacterium to avoid lysosomal digestion for up to 72 hours. This enhances survival and persistence of bacterium within the host. The Campylobacter jejuni bacterium releases enterotoxins and cytotoxins. And these contribute to inflammation and diarrhea. Inflammation of intestinal mucosa often occurs. That is accompanied by blood in stool. Flagella facilitates immotility, biofilm formation, and host interactions. Campylobacter jejuni navigates toward favorable environments using chemotaxis. Systemic infection occurs in neonates and debilitated adults.
Clinical findings. Enterocolitis caused primarily by Campylobacter jejuni begins with a watery, foul-smelling diarrhea that is followed by bloody stools accompanied by fever and abdominal pain. And that's severe. And there's also headache, nausea, and vomiting. Systemic infections, most commonly bacteremia, are caused most often by Campylobacter intestinalis. The symptoms of bacteremia like fever and malaise are associated with no physical findings.
Complications. We know bacteremia, the systemic infection is going to be one of them. Then the gastrointestinal infection caused by Campylobacter jejuni is associated with Guillain-Barré syndrome. The most common cause of acute neuromuscular paralysis. Guillain-Barré syndrome is an autoimmune disease attributed to the formation of antibodies against Campylobacter jejuni that cross-react with antigens on neurons. Infection with Campylobacter is also associated with two other autoimmune diseases: the reactive arthritis and uveitis syndrome. Miscarriage is also one of the complications.
Lab diagnosis. We'll need the samples of feces and blood. Then we'll go for Gram staining. On Gram staining, Campylobacter jejuni comes to be Gram-negative because it's pink colored. If you guys want to know more about Gram staining, I do have videos on them. Be sure to check out the channel. And then we'll go for microscopy. Under microscope, Campylobacter jejuni is curved, comma-shaped, coccoid, or s-shaped bacterium. It varies in size from 0.5 to 5 micrometers by 2 to 9 micrometers. It is pink colored. This is how it looks like under the microscope.
If the patient has diarrhea, a stool specimen is cultured on a blood agar plate that contains antibiotics that inhibit most fecal flora. But there are certain conditions that are provided to the agar plate. The plate is incubated at 42°C in microaerophilic atmospheric conditions containing 5% oxygen and 10% carbon dioxide that favors the growth of Campylobacter jejuni. It is identified by failure to grow at 25°C temperature, oxidase positivity, and sensitivity to nalidixic acid. Unlike Shigella and Salmonella, lactose fermentation is not used as a distinguishing feature. If bacteremia is suspected, a blood culture incubated under standard temperature and atmospheric conditions will reveal the growth of characteristically comma or s-shaped motile Gram-negative rods. Identification of organisms as Campylobacter intestinalis is confirmed by its failure to grow at 42°C temperature, its ability to grow at 25°C temperature, and its resistance to nalidixic acid.
Treatment. We'll go for rehydration therapy because there is dehydration. We'll go for infusion of water and electrolytes. We'll go for erythromycin and azithromycin for the infection caused by Campylobacter jejuni. And aminoglycoside for the infection caused by Campylobacter intestinalis.
Prevention. Proper sewage disposal and personal hygiene like proper hand washing can help prevent the infection. Avoid drinking unpasteurized milk or treated water. Avoid eating undercooked poultry products, like properly cooking them and then eat them. And there's no vaccine to prevent the infections caused by Campylobacter.
All right guys, let's show you everything really quick. The organism we discussed today is Campylobacter jejuni. It is responsible for causing diarrhea, enterocolitis, gastroenteritis. And there are certain complications like bacteremia, Guillain-Barré syndrome, reactive arthritis, and uveitis syndrome. Transmission is via fecal-oral route. And is transmitted via eating or consuming water or food contaminated with animal feces, by consuming undercooked food, by consuming unpasteurized milk. Hosts of humans and domestic animals like cattle, chickens, and dogs. Diagnosis is based on Gram staining, microscopy, and culture. Treatment will go for rehydration therapy, erythromycin and azithromycin in case of infections caused by Campylobacter jejuni. And aminoglycoside for the infections caused by Campylobacter intestinalis.
And that's it for today's video. I hope you guys enjoyed it. You've learned something. If you guys have got any suggestions, feel free to leave them below in the comments. And if you want to connect with me on my socials, I've got my Instagram with the handle MedZ. And also Twitter. And I'll catch you in the next video. Till then, Asalamu alikum.