Clostridium 🔬🧫 | скачать в хорошем качестве

Clostridium 🔬🧫 |

CLOSTRIDIUM: INTRODUCTION: Clostridium is a genus of Gram-positive bacteria. This genus includes several significant human pathogens, including the causative agents of botulism and tetanus. The genus formerly included an important cause of diarrhea, Clostridioides difficile, which was separated after 16S rRNA analysis. Some of the species classified under the genus Clostridium include: C. botulinum C. perfringens C. sporogenes C. bifermentans C. leptum C. difficile TOXINS: 1. Neurotoxins 2. Botulinum Toxin (BoNT) 3. Tetanus Toxin (TeNT) 4. Enterotoxin PATHOGENESIS: Toxins mediate the Clostridial histiotoxic syndromes. Toxins are biologically active proteins that are antigenic and capable of neutralization by specific antisera. C. perfringens produces 4 major lethal toxins, based on which it is classified into 5 serological types classified A to E. Additional virulence factors include enterotoxin, neuraminadase and haemolysins. The role of clostridia in the pathogenesis of polmicrobial infections is unclear. Clostridium perfringens is the most common clinical isolate of the genus. It is a ubiquitous bacterium associated with several exotoxin-mediated clinical diseases. There are 12 recognized toxins, and the species is divided into types A through E on the basis of the spectrum of toxins produced. The disease syndromes caused by C. perfringens are food poisoning, necrotizing enteritis, and gas gangrene. CLINICAL MANIFESTATIONS: Infections caused by these organisms range from a variety of localized wound contamination to overwhelming systemic disease. Clostridial histiotoxic syndromes are mediated by toxins and include soft tissue infections such as gas gangrene (caused by C. perfringens), enteric diseases such as clostridial food poisoning, enteritis necroticans, antibiotic associated colitis (caused by C. difficile ), discussed elsewhere, and neutropenic enterocolitis (caused by C. septicum) and neurological syndromes such as tetanus and botulism (both discussed elsewhere). C. septicum can cause spontaneous, non-traumatic gas gangrene, and C. sordellii can induce gas gangrene of the uterus, as a consequence of spontaneous abortion, normal vaginal delivery and traumatic injury. Clostridial bacteremia account for clinically significant anaerobic bacteremia second only to Bacteroides spp. Clostridia are also often isolated from polymicrobial intraabdominal, biliary, pleuropulmonary, central nervous system, genitourinary and skin and soft tissue infections. LABORATORY DIAGNOSIS: Isolation of Clostridia from wound, pus, blood or faeces, along with toxin and serological assays aid in the diagnosis of clostridial infections. The significance of clostridia in polymicrobial isolates is unknown. Clinical diagnosis is especially important in infections such as gas gangrene in which demonstration of clostridial myonecrosis is critical in the diagnosis. SUSPECTIBILITY: C. perfringens: C. perfringens, as well as most other Clostridium spp. are generally, but not universally susceptible to penicillin-G, amoxicillin, ticarcillin, piperacillin, cefazolin, cefoxitin, cefotetan, third generation cephalosporins, chloramphenicol, clindamycin, macrolides, metronidazole, imipenem, meropenem, tetracycline, tigecycline, fluoroquinolones, vancomycin, daptomycin, quinupristin-dalfopristin, rifampin, and the combinations of penicillins and beta-lactamase inhibitors OTHER SPECIES OF CLOSTRIDIUM: With some exceptions, strains of Clostridium have been found to express resistance by one or more of the beta-lactamases. Beta–lactamase producing Clostridium spp. express enzymes that are generally inhibited by clavulanic acid Rifampin and chloramphenicol occasionally lack bactericidal activity against C. perfringens. Cefoxitin is less effective against Clostridium spp. than most other cephalosporins. There is increasing resistance of C. perfringens as well as other clostridia species to antimicrobials; C. ramosum,and C. innocuum, show increased resistance to penicillin (16-57%), cefoxitin (22-48%), other cephalosporin (20%), clindamycin (5-50%), flouroquinolones, and metronidazole (11-12%). VACCINE: There are currently no vaccines for these bacteria. A polyvalent vaccine against C. histolyticum, C. novyi, C. septicum and C. perfringens was developed in the 1930th (SB). Because the toxoiding alpha toxin from C. perfringens was incudedonly low titers of anti-alpha toxin antibody this approach was abandoned. were elicited. However , several recent studies demonstrated that active immunization with crude toxoid preparations were protective in experimental infections. Greetings from Microbial Life : WE, I & MICROBES Thank you🙏 Regards AVIZEET HALDER •Microbiologist •Community Immunity Ambassador(UAEaid,Dubai) •Co-founder & Chief Editor(Microbial Life WIM)