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Antimicrobial Agents and Chemotherapy May 2024Mycetoma is a devastating neglected tropical infection of the subcutaneous tissues. It is caused by fungal and bacterial pathogens recognized as eumycetoma and...
Mycetoma is a devastating neglected tropical infection of the subcutaneous tissues. It is caused by fungal and bacterial pathogens recognized as eumycetoma and actinomycetoma, respectively. Mycetoma treatment involves diagnosing the causative microorganism as a prerequisite to prescribing a proper medication. Current therapy of fungal eumycetoma causative agents, such as , consists of long-term antifungal medication with itraconazole followed by surgery, yet with usually unsatisfactory clinical outcomes. Actinomycetoma, on the contrary, usually responds to treatment with co-trimoxazole and amikacin. Therefore, there is a pressing need to discover novel broad-spectrum antimicrobial agents to circumvent the time-consuming and costly diagnosis. Using the resazurin assay, a series of 23 naphthylisoquinoline (NIQ) alkaloids and related naphthoquinones were subjected to screening against two fungal strains of and three bacterial strains of and . Seven NIQs, mostly dimers, showed promising activities against at least one strain of the mycetoma-causative pathogens, while the naphthoquinones did not show any activity. A synthetic NIQ dimer, 8,8'''-,-dimethylmichellamine A (), inhibited all tested fungal and bacterial strains (IC = 2.81-12.07 µg/mL). One of the dimeric NIQs, michellamine B (), inhibited a strain of and significantly enhanced the survival rate of larvae infected with at concentrations of 1 and 4 µg/mL, without being toxic to the uninfected larvae. As a result, broad-spectrum dimeric NIQs like and with antimicrobial activity are considered hit compounds that could be worth further optimization to develop novel lead antimycetomal agents.
Topics: Mycetoma; Antifungal Agents; Animals; Alkaloids; Microbial Sensitivity Tests; Madurella; Isoquinolines; Actinomadura; Naphthoquinones; Larva; Moths
PubMed: 38602413
DOI: 10.1128/aac.01612-23 -
International Journal of Microbiology 2024complex (MTBC) is a group of bacteria responsible for causing tuberculosis in animals and humans. In South Africa (S.A), slaughterhouses are registered by the...
complex (MTBC) is a group of bacteria responsible for causing tuberculosis in animals and humans. In South Africa (S.A), slaughterhouses are registered by the government and closely inspected and audited for hygienic slaughter practices. Meat inspection to detect lesions has been used for passive surveillance, monitoring, and diagnosis of the disease status. Information on the current status of bovine tuberculosis (bTB) in livestock in the country is limited. Hence, we investigated the occurrence of spp. in the tissues of slaughtered livestock and environmental samples in abattoirs in Gauteng province of South Africa (S.A). The cross-sectional study employing random sampling from cattle, pigs, and sheep (with the collection of liver, lung, spleen, and different lymph nodes) irrespective of lesions was carried out in 19 red meat abattoirs. Five hundred animals were sampled, comprising cattle ( = 369), pigs ( = 90), and sheep ( = 41). Additionally, 19 environmental samples were collected from feedlots, or where animals drink water while awaiting slaughter, to identify mycobacterial species using culture, acid-fast bacteria staining, and polymerase chain reaction (PCR). The Chi-square and Fisher's Exact tests were used to detect statistically significant differences in the frequency of detection of spp. according to the variables investigated (types of tissues, livestock, abattoirs, etc.). The PCR assays detected no MTBC complex species DNA in the bacterial isolates from cattle ( = 32). Sequence analysis (16S rDNA) of the isolates from eight cattle confirmed only two species, namely (99.81% identity) and (99.42% identity). The remaining isolates were identified as members of the species. From the environmental samples, bacterial isolation was made from three samples, and two could only be identified up to the genus level ( species) while the remaining isolate was identified as (99.22% identity). The study revealed the absence of bovine tuberculosis-causing pathogens in red meat abattoirs of the Gauteng province. Although non-tuberculous have been implicated as potentially causing tuberculosis-like diseases in livestock, their occurrence in the current study was found to be low, but the potential to cause disease cannot be ignored.
PubMed: 38523690
DOI: 10.1155/2024/4636652 -
Journal of Natural Products May 2024A chemical investigation of Australian soil-derived bacteria sp. S4S-00069B08 yielded eight new benzenoid ansamycins, goondansamycins A-H. Goondansamycins feature rare...
A chemical investigation of Australian soil-derived bacteria sp. S4S-00069B08 yielded eight new benzenoid ansamycins, goondansamycins A-H. Goondansamycins feature rare 1,4-benzoxazin-3-one or -diamino--benzoquinone moieties and can exist as both aglycones or 9--α-glycosides of either d-rhodinose or d-amicetose. Structures were solved on the basis of detailed spectroscopy, including X-ray analysis.
Topics: Australia; Molecular Structure; Soil Microbiology; Actinomadura; Benzoquinones; Crystallography, X-Ray
PubMed: 38747559
DOI: 10.1021/acs.jnatprod.4c00336