Sarcina ventriculi a rare pathogen

Sarcina ventriculi is a gram-positive bacterium, able to survive in extreme low pH environment. It's first description dates from 1842, by John Goodsir. Since then, just a few cases have been reported. In veterinary medicine, especially in ruminants, it causes bloating, vomiting, gastric perforation and death of the animal. It is commonly associated with delayed gastric emptying or obstruction to gastric outlet, although it's pathogenicity in humans is not fully understood. We report two cases with identification of the bacteria in gastric specimens stained with hematoxylin-eosin staining, in different clinical settings. The first patient is a young female patient, presenting cardiac arrest and death after gastric perforation and the second patient an adult male presenting with gastric adenocarcinoma, treated with partial gastrectomy followed by adjuvant chemoradiation. In our literature review, we identified forty-five cases reporting Sarcina ventriculi appearance, with a sudden increase since 2010.

Solution structure and antibacterial mechanism of two synthetic antimicrobial peptides / 生物工程学报

Mytilin-derived-peptide-1 (MDP-1) and mytilin-derived-peptide-2 (MDP-2) are two truncated decapeptides with reversed sequence synthesized corresponding to the residues 20-29 of mytilin-1 (GenBank Accession No. FJ973154) from M. coruscus. The objective of this study is to characterize the structural basis of these two peptides for their antimicrobial activities and functional differences, and to investigate the inhibitory mechanism of MDPs on Escherichia coli and Sarcina lutea. The structures of MDP-1 and MDP-2 in solution were determined by 1H 2D NMR methods; the antibactericidal effects of MDPs on E. coli and S. lutea were observed by transmitted electron microscopy (TEM). Both MDP-1 and MDP-2 have a well-defined loop structure stabilized by two additional disulfide bridges, which resemble the-hairpin structure of mytilin-1 model. The surface profile of MDPs' structures was characterized by protruding charged residues surrounded by hydrophobic residues. TEM analysis showed that MDPs destroyed cytoplasmic membrane and cell wall of bacteria and the interface between the cell wall and membrane was blurred. Furthermore, some holes were observed in treated bacteria, which resulted in cell death. Structural comparison between MDP-1 and MDP-2 shows that the distribution of positively charged amino acids on the loop of MDPs is topologically different significantly, which might be the reason why MDP-2 has higher activity than MDP-1. Furthermore, TEM results suggested that the bactericidal mechanisms of MDPs against E. coli and S. lutea were similar. Both MDP-1 and MDP-2 could attach to the negatively charged bacterial wall by positively charged amino acid residues and destroy the bacteria membrane in a pore-forming manner, thus cause the contents of the cells to release and eventually cell death.

Screening of antimicrobial potential of certain drug plants for enhancement of their therapeutic spectrum in vitro

Present paper deals with the in vitro screening of antimicrobial potential of Azadirachta indica and Holarrhena antidysenterica against four bacterial test species i.e. Escherichia coli, Sarcina lutea, Bacillus megaterium and Bacillus species for enhancement of their therapeutic spectrum. During this investigation, A. indica has shown more antimicrobial potential than H. antidysenterica against all bacterial species except Bacillus species. Maximum antibacterial activity was found at 100% of each drug plant extract which established a positive correlation between drug concentration and antimicrobial potential. Lowest antibacterial activity was found at 10% concentration. No activity was found against E. coli in H. antidysenterica. Investigation on drug potency at 100% concentration in terms of unit strength compared with different antibiotics, yielded that one ml of A. indica extract was equal to 5 units of Ciprofloxacin for B. megaterium and Bacillus species, and 4.2 units for E. coli. Low potency was recorded in Ampicillin than Ciprofloxacin. Drug extract of H. antidysenterica showed more unit when compared with Ciprofloxacin than Ampicillin for all bacterial test species

Atividade antibacteriana de extratos de Bidens pilosa L / Antibacterial activity of Bidens pilosa L. extracts

Foram preparados extratos de plantas de B. pilosa provenientes de diferentes regiöes as quais mostraram atividade contra S. aureus. Extratos preparados a 80ºC näo apresentaram atividade. Foi testada a atividade antibacteriana do extrato bruto de B. pilosa contra S. aureus, S. lutea e B. subtilis cultivados sob cinco diferentes valores de pH e, para isto, mediu-se o crescimento através da turvaçäo e da atividade catalásica. A S. lutea apresentou a maior sensibilidade. Dos diferentes solventes orgânicos utilizados no fracionamento do extrato bruto, o clorofórmico foi o melhor. Na avaliaçäo da presença de princípio ativo em diferentes fases do desenvolvimento de B. pilosa, a fase cotiledonar apresentou menor concentraçäo do princípio ativo e a fase de flor a maior concentraçäo