The Filtration Of Culture Media For Haemophilus Ducreyi

ObjectiveTo investigate the rate of chancroid in clinical samples of genital ulceration with selective culture media for haemophilus ducreyi.MethodsSix swabs were taken from the genital ulceration in a same patient to be inoculated in five self-made culture media which are composed of V-Agar, GC-CtS, C-HgCh, MH-HBC(Modified) and MH-HBC, and tested with the clinical tests of dark-field microscopy, TRUST, TPPA and HSV-DNA. With the positive outcome for haemophilus ducreyi inoculation in hand, five biochemical tests, that is, alkaline phosphatase, catalase test, nitrate reduction, oxidase test and porphyin test would then be used to identify further. Preserve the haemophilus ducreyi strain(s) with biochemical positiveness.ResultsIn all 150 cases contained in this experiment, one genital ulcerated sample got grown well in one culture medium, V-Agar, and its colony could burden five biochemical tests, namely, alkaline phosphatase (positive), catalase test (negative), nitrate reduction (positive), oxidase test (positive) and porphyrin test (negative). No haemophilus ducreyi growth was observed in culture media GC-CtS, C-HgCh, MH-HBC(Modified) and MH-HBC, respectively. After re-inoculation, the new colony became smaller in the same culture medium under the same culture condition.The positivity of Dark-field, TRUST, TPPAand HSV-DNA were 29, 64, 73 and 62 case(s), relatively. In clinical data, the types of skin lesion were composed of ulcer, bullus and crest accordingly, and, the skin lesions located over the genital-anal region, such as coronet (36 cases), penis trunk (24 cases), chalaza (20 cases), penis root (13 cases), glans (11 cases), foreskin (7 cases), crissum (6 cases), nympha (5 cases) and perineum (2 cases).ConclusionIn all the genital samples, only one could flourish colony normally in one culture medium of five media, in V-Agar, and the colony could receive five biochemical tests. The same medium, V-Agar, harvested the same reaction for two standard haemophilus ducreyi strains in pre-testing ahead. How about the explanation of one case of diagnosis only for chancroid in so many samples as following: (1) lower rate of chancroid; (2) culture medium V-Agar catering the nutrients for haemophilus ducreyi; (3) haemophilus ducreyi born with fastidious requisite for nutrition and different nutrient list in different regions; (4) some ducreyi strains sensitive to vancomycin; (5) improper operation in dealing with specimens. In sexual transmitted diseases clinics, though there emerged kinds of culture media for haemophilus ducreyi over the last 30 years, the possibility of co-infections of syphilis, genital herpes, and so on, the delayed inoculation with the samples, the sub-growing condition in culturing, the sensitive strains to vancomycin, etc., would all lead to the negative culturing. With modern techniques in China, definitive chancroid could be diagnosed infrequently, but yet, as a clinical dermatologist, the diagnosis for chancroid should be kept in mind, especially when the multiple ulcers are painful and with adenopathy in groin simultaneously. There is a common phenomenon for the diversity existed between the clinical diagnosis and laboratory examination of TRUST, TPPA and HSV-DNA.In addition, there existed original creation and new field in this research: 1. no relative reports on culturing of clinical chancroid in China until now; 2. no reports on using five kinds of culture media and five biochemical tests for the culturing andidentification for haemophilus ducreyi all over the world until now, respectively.