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Tropical genital and sexually acquired infections
Published in Shiv Shanker Pareek, The Pictorial Atlas of Common Genito-Urinary Medicine, 2018
Haemophilus ducreyi is a short gram-negative coccobacillus (Fig. 13.1.1) – a rod-shaped bacterium which cannot live outside its human host. The organism produces a toxin that contributes to the cause of the characteristic ulcers and delays healing.
Infectious disease and GUM
Published in Ashley Bond, MRCP Part 2 Examination, 2017
Chancroid: due to infection with Haemophilus ducreyicommon in Caribbean, Africa and South West Asia.
Streptomycin
Published in M. Lindsay Grayson, Sara E. Cosgrove, Suzanne M. Crowe, M. Lindsay Grayson, William Hope, James S. McCarthy, John Mills, Johan W. Mouton, David L. Paterson, Kucers’ The Use of Antibiotics, 2017
Haemophilus ducreyi resistant to streptomycin and kanamycin has been reported. Resistance is mediated by a plasmid that encodes the production of two aminoglycoside-modifying phosphotransferases (Sanson-le Pors et al., 1985).
An overview of properties of Amphora (Acidform) contraceptive vaginal gel
Published in Expert Opinion on Drug Safety, 2018
However, most research in developing new spermicidal compounds has focused on products that maintain the acidity of the vaginal pH in its natural range from 3.5 to 4.5. That range normally is achieved in vivo by the release of hydrogen peroxide and lactic acid from resident lactobacilli. At that pH, sperm are immobilized. Immobilization is more rapid at lower pH levels; at a pH of 4.0, sperm are completely immobilized within 30 s, but at a pH of 5.0, immobilization takes 5 min [40]. Similarly, the rate at which sperm are killed is linearly proportional to pH. At pH of 4.0, all sperm are dead within 10 min, but at a pH of 4.5, it takes 15 min to kill them all [40]. Low vaginal pH also provides a measure of protection against STIs. HIV is inactivated at low pH as are Neisseria Gonorrhoeae, Herpes Simplex Virus, Chlamydia trachomatous and Haemophilus ducreyi; the growth of many organisms associated with bacterial vaginosis (BV) is virtually halted at low pH levels [41]. To protect the sperm, semen has a pH of 7.2–8.0 and has good buffering properties. The ejaculate typically raises the pH of the vagina above six for several hours, which permits the sperm to remain intact and mobile and HIV and other STI organisms to survive [42].
The ancestral stringent response potentiator, DksA has been adapted throughout Salmonella evolution to orchestrate the expression of metabolic, motility, and virulence pathways
Published in Gut Microbes, 2022
Helit Cohen, Boaz Adani, Emiliano Cohen, Bar Piscon, Shalhevet Azriel, Prerak Desai, Heike Bähre, Michael McClelland, Galia Rahav, Ohad Gal-Mor
DksA was previously shown to regulate pathogenicity and virulence-associated phenotypes in multiple Gram-negative animal and plant pathogens, including the expression of the T3SS in Erwinia amylovora50,51 and the growth of Xanthomonas citri in its host plants.52 In Pseudomonas aeruginosa, DksA was reported to coordinate quorum sensing, anaerobiosis, and motility53,54 and to affect the production of the cholera toxin and hemagglutinin protease in Vibrio cholera.55,56 In Haemophilus ducreyi, DksA was also reported to regulate pathogenicity,57 and the expression of T4SS in Bartonella henselae.58 In Legionella pneumophila, DksA was shown to be involved in stationary-phase survival, flagellar gene activation, lysosome avoidance, and macrophage cytotoxicity,59 and in Campylobacter jejuni, a dksA mutant strain was impaired in invading intestinal cells and manipulating the host immune response.60 Furthermore, DksA was demonstrated to control the expression of the genes in the LEE pathogenicity island in Enterohaemorrhagic E. coli61 and to be involved in virulence and intercellular spread of Shigella flexneri.62 Finally, in S. Typhimurium, DksA was reported to play a role in resistance to reactive oxygen and nitrogen species,33,35 and a dksA mutant strain was significantly impaired in host cells invasion24 and attenuated in J774A.1 macrophage-like cells,63 chicken64 and mouse24,65 infection models.
Imbalance of the intestinal virome and altered viral-bacterial interactions caused by a conditional deletion of the vitamin D receptor
Published in Gut Microbes, 2021
Jilei Zhang, Yongguo Zhang, Yinglin Xia, Jun Sun
To further evaluate the altered bacterial composition, we showed the altered bacterial species with q-values <0.1 in differential analysis in our three mouse models (Figure 4b). We found that Haemophilus ducreyi and Mesorhizobium huakuii were significantly depleted in VDRΔIEC mice compared with control VDRLoxP mice (Figure 4b). Meanwhile, five bacterial species were significantly depleted, and three bacterial species were significantly enriched in VDRΔPC mice, compared with the control. These depleted species were Haemophilus ducreyi Kushneria konosiri, Microbacterium sp. LKL04, Isosphaera pallida, and Actinomyces radingae. Three enriched bacterial species were Bacteroides uniformis, Faecalibaculum rodentium, and Cutibacterium acnes (q < 0.01. Figure 4b). Furthermore, we found that nine bacterial species were significantly depleted, and three bacterial species were enriched in VDRΔLyz mice. These depleted bacterial species were Bifidobacterium pseudolongum, Bifidobacterium choerinum, Bifidobacterium animalis, Bordetella pseudohinzii, Haemophilus ducreyi, Clostridium perfringens, Streptomyces peucetius, and Bacteroides acidifaciens. The three enriched bacterial species were Ralstonia solanacearum, Chroococcidiopsis thermalis, and Cutibacterium acnes (Figure 4b). The less abundant Haemophilus ducreyi is a gram-negative bacterium and causative agent of genital ulcer disease chancroid47 and was detected in the three conditional VDR knockout mice. Similar to viruses, more bacterial species were enriched (7 in total) or depleted (24 in total) in VDRΔPC and VDRΔLyz mice compared to the control mice (Figure 4b).