(I. Overview Campylobacter bacteria are a type of microaerophiles that do not decompose sugars, are positive for oxidase, and are bent, comma-shaped, S-shaped, or spiral-shaped, and are dynamic Gram-negative bacteria. Including 5 species and 5 subspecies. The main pathogenic factors for humans are Campylobacter jejuni and fetal Campylobacter fetus subspecies. The former is one of the most common pathogens of human diarrhea, and the latter can cause sepsis and meningitis when the immune function is low. Source: Examination (2) Biological characters 1. Morphological staining: Gram-negative, slender, spiral, or seagull wings, S-shaped Campylobacter. There is a single flagella at one or both ends, which is lively and sometimes spiral. Single flagella at one end is more common in fetal subspecies, and single flagella at both ends is more common in Campylobacter jejuni, with no spores and no capsule. 2. Cultivation characteristics: Micro-aerobic bacteria need to grow in a gas environment containing 5% O2, 85% N2, and 10% CO2 for the first separation, and can grow in a 10% CO2 environment during subculture. The optimum growth temperature of this genus of bacteria varies with the species (the difference in growth temperature can be used as the main point of bacterial identification). http://ks.examda.com The nutritional requirements are high, and it does not grow on ordinary media. Need to add blood and serum to grow. Common selection media include Skirrow agar and Campy-BAP medium. These mediums are based on blood agar and added with a variety of antibiotics, which can inhibit the normal intestinal flora and facilitate the separation of the bacteria. Medicine | Education Network collects and organizes the first separation of Campylobacter jejuni, after 48h culture can form two colonies; one is flat, moist, gray, translucent, irregular edges, often spread along the inoculation colony; the other It is round, convex, translucent, needle-shaped, shiny, and a single small colony. Both colonies are not hemolytic. It grows evenly and turbidly in Brine broth. 3. Biochemical reaction: The biochemical reaction of this genus is inactive. No decomposition of sugar, no liquefied gelatin, no decomposition of urea, VP and methyl red test were negative. Oxidase is positive, most Campylobacter can reduce nitrate, catalase test is positive, Campylobacter jejuni hydrolysate test is positive. 4. Antigen structure: there are bacterial (O) antigen, heat-labile antigen and flagella (H) antigen. According to the O antigen, Campylobacter jejuni can be divided into 42 serotypes. 5. Resistance: The resistance is weak, and it will be killed at 56 ℃ for 5 minutes. It can only survive for 3 hours in a dry environment. (3) Microbiological examination 1. Specimen collection: immediate inspection and timely inoculation. 2. Inspection methods and identification (1) Direct smear 1) Examination of hanging drop specimens: Observe the presence of bacteria with dart or spiral movement under a microscope. 2) Gram stain check: Gram-negative comma-shaped, S-shaped or spiral-shaped small bacilli. (2) Isolation and culture: Stool and anal swab specimens are directly inoculated on modified Campylobacter agar plates such as modified Skir-row blood agar plates and Campy-BAP plates; blood or cerebrospinal fluid specimens are inoculated with Brine broth and then transferred The culture medium of Campylobacter was separated and cultured at 42 ℃ and 37 ℃ under micro-aerobic environment for 24-72h, and the colony characteristics were observed. (3) Identify Gram-negative Campylobacter parvum, single flagella have dart-like or spiral-like power, do not grow in aerobic environment, under micro-aerobic conditions, two types of colonies are formed on the medium for selection of Campylobacter. Does not break down glucose. The main points of identification of Campylobacter are oxidase positive, Gram negative, and the bacterial body is curved or S-shaped. The most commonly used identification tests are growth temperature (25 ℃, 37 ℃, 42 ℃) test, catalase test, hippurate hydrolysis test, nitrate and nitrite reduction test, hydrogen sulfide test, etc. (4) Clinical significance The pathogenic factors are mainly related to enterotoxin, cytotoxin, endotoxin and adhesion and colonization ability. Mainly cause human intestinal infections and various extraintestinal infections. Campylobacter jejuni is one of the most common bacteria causing sporadic bacterial enteritis. Campylobacter fetus mainly causes extraintestinal infections, in which fetal subspecies is the main human pathogen, causing bacteremia, cholecystitis, peritonitis, and lung infections. (5) Treatment principles Campylobacter jejuni is often sensitive to erythromycin, clindamycin, and tetracycline. Most Campylobacter jejuni is sensitive to aminoglycosides, chloramphenicol, and fluoroquinolones. Because it can produce β-lactamase, it is generally sensitive to β-lactamase. Class resistance. Aluminium Forged Wok,Anodized Forged Wok,Anodized Aluminum Forged Wok,Cast Aluminum Forged Wok HOMEARTS INDUSTRIAL CO.,LTD , http://www.kitchenworks.cc
January 20, 2021