The optimum growth temperature of Bacillus Feingold is 30℃. After 48 hours of culture in blood dish, gray-white, smooth, slightly convex, opaque and hemolytic colonies were formed, with a diameter of 0.5 ~ 1.2 mm and a candy flavor. After incubation for 48 hours, some strains were easily negative by Gram staining. Microscopically, bacteria are spherical or oval, and most of them are arranged in double or short chains, long chains or piles.
The onset time of infection is long, the initial infection often has no obvious symptoms, the onset is hidden, the abscess grows rapidly, and there is often no history of external injury. The infected site has swelling, pain and ulceration in different degrees. Some cases have basic diseases (diabetes), and most of them have no obvious inducement. The diagnosis of feingold infection is mainly based on obtaining enough samples from the infected site for culture, but the identification of strains is relatively difficult.
The most important thing in routine treatment is drainage and debridement, and antibacterial drugs are given at the same time.
Clindamycin, erythromycin, amoxicillin/clavulanic acid, ampicillin/sulbactam, piperacillin/tazobactam/meropenem, amoxicillin/metronidazole, etc. This part of the information comes from the literature.
Bacillus Feingold is one of the most common gram-positive anaerobic bacteria in skin, which can be isolated from various clinical specimens. The virulence factor of Bordetella Feingold makes it a highly pathogenic conditional pathogen of GPAC, and it is also one of the most common pathogens in the cause of septic arthritis associated with postoperative prosthesis implantation, accounting for 20%~40% of all GAPC infections.
Studies have shown that immunosuppression and malnutrition are recognized as the causes of disease. Staphylococcus aureus, micrococcus and Corynebacterium on the skin surface help to protect the host from more pathogenic microorganisms. But when the host's immune defense mechanism is destroyed, or the microbial balance is destroyed, these bacteria will become conditional pathogens and cause infection. In the past few decades, the widespread use of antibacterial drugs has disturbed the normal flora. In addition, aging, the introduction of foreign materials and equipment (artificial heart valves, joint replacement, catheters, etc. ) and the extensive use of immunosuppressants have led to a sharp increase in clinical infections caused by conditional pathogens, including anaerobic bacteria. According to reports, among the skin and soft tissue infections, the probability of anaerobic bacteria infection such as gas gangrene, breast abscess, necrotizing cellulitis, perianal and perirectal abscess, diabetic gangrene, post-traumatic infection and acne is 70%- 100%, and anaerobic bacteria such as wound infection, abscess, cellulitis, necrotizing fasciitis, bite, diabetic foot infection and infectious bedsore. Staphylococcus aureus is the main anaerobic bacteria isolated from non-postpartum breast abscess.
Studies have shown that the blood cultures of infective endocarditis caused by feingold bacteria are all negative, and the pathogenic bacteria can only be obtained by submitting relevant tissue samples. In mediastinal inflammation, 67% or blood culture is negative, and the reasons for negative blood culture may mainly be as follows: (1) Limited by the technical conditions of culture; (2) It is related to the type and location of infection; (3) It is determined by the characteristics of pathogenic bacteria. (4) Experience in antimicrobial therapy.
Worldwide, the drug resistance of anaerobic bacteria is increasing. More than 90% of feingold bacteria are sensitive to penicillin and generally sensitive to other β-lactams. However, they are resistant to clindamycin, metronidazole and quinolones to varying degrees [19-20]. The resistance rate of GPAC to clindamycin is 7% ~20%, and the resistance rate to Faingold [18] is high. Therefore, clindamycin should be used cautiously for the infection caused by feingold, and the drug sensitivity test will be of great help to correct clinical medication and drug selection. The most important thing in routine treatment is drainage and debridement, and at the same time, empirical antibacterial drugs are given. Drug sensitivity tests can be carried out for anaerobic bacteria infection in special parts or when the curative effect of empirical administration is not good, such as bacteremia, brain abscess, endocarditis, osteomyelitis, joint infection, prosthesis infection and so on. [15]. At present, the research shows that 5 ~ 7 days of antibacterial treatment is enough for the clinical treatment of skin and soft tissue infection, but it usually takes 2 weeks [2 1]. However, according to the clinical symptoms, the administration cycle was extended to 4 weeks to ensure that the symptoms of infection were completely relieved. This is because the growth of Feingold's bacteria is slow and it is easy to produce antibiotic resistance. After infection, the course of disease will be prolonged, and the Feingold's bacteria in chronic infected wounds will also slow down the process of wound healing [5].
The ability of domestic microbiology laboratories to detect anaerobic bacteria needs to be improved. The reasons for the low detection rate of anaerobic bacteria in clinical specimens may be as follows: (1) Anaerobic culture requires anaerobic balloon or anaerobic culture instrument, which is expensive and has not been routinely carried out in many laboratories; (2) Because anaerobic bacteria generally grow slowly and have small colonies, some anaerobic bacteria need to grow for 3 to 5 days; (3) The existence of anaerobic bacteria is not considered in the process of specimen inspection. When specimens are collected and transported, they are exposed to air or transported at low temperature, and anaerobic bacteria are easy to die. Therefore, microbiology laboratory personnel need to improve their awareness of active service. Because clinicians often only open ordinary culture, many pus, wound secretions and other specimens are directly inoculated with blood plates without direct smear Gram staining. When aerobic culture does not grow for 48 h, it will report "no bacterial growth", which is easy to cause anaerobic bacteria to miss detection. It is necessary to strengthen the communication between microbial inspectors and clinic, strengthen the awareness of active service, realize the importance of direct smear staining, facilitate the distinction between wound pollution (showing a large number of epithelial cells) and infection (showing bacteria and inflammatory cells at the same time), and also judge whether there is bacteria in the specimen and report it to clinic quickly.
To sum up, the pure culture of different clinical specimens clearly confirmed the clinical significance of feingold. However, most anaerobic bacteria grow slowly and have small colonies, which are easy to be missed and ignored, resulting in a low isolation rate of anaerobic bacteria in clinical infection cases. Microbiology laboratory should adopt correct culture methods and choose suitable culture conditions, so as to accurately find pathogenic bacteria, shorten the diagnosis time and use correct antibacterial drugs as soon as possible.
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