A brief multi-disciplinary review on antimicrobial resistance in medicine and its linkage to the global environmental microbiota.

The discovery and introduction of antimicrobial agents to clinical medicine was one of the greatest medical triumphs of the 20th century that revolutionized the treatment of bacterial infections. However, the gradual emergence of populations of antimicrobial-resistant pathogenic bacteria resulting from use, misuse, and abuse of antimicrobials has today become a major global health concern. Antimicrobial resistance (AMR) genes have been suggested to originate from environmental bacteria, as clinically relevant resistance genes have been detected on the chromosome of environmental bacteria. As only a few new antimicrobials have been developed in the last decade, the further evolution of resistance poses a serious threat to public health. Urgent measures are required not only to minimize the use of antimicrobials for prophylactic and therapeutic purposes but also to look for alternative strategies for the control of bacterial infections. This review examines the global picture of antimicrobial resistance, factors that favor its spread, strategies, and limitations for its control and the need for continuous training of all stake-holders i.e., medical, veterinary, public health, and other relevant professionals as well as human consumers, in the appropriate use of antimicrobial drugs.

Different DNA-binding proteins in the primary and secondary forms of Xenorhabdus luminescens.

Basic, heat-stable proteins binding to double-stranded DNA (HASP) were isolated from the primary and secondary forms of Xenorhabdus luminescens and their composition compared. Two of the proteins with low molecular weight are present in both the primary and secondary forms, whereas two others are present only in the latter. The described protein fractions may be involved in the regulation of transitions between the two forms of X. luminescens.

Structure of cell envelope components of the primary and secondary forms of Xenorhabdus luminescens.

Muropeptide analysis of muramidase-digested murein (peptidoglycan) did not reveal any differences between the primary and secondary forms of Xenorhabdus luminescens. Similarly, no significant differences were found in the overall protein composition of the cytoplasmic and outer membranes of both forms.

Autolysis of Listeria monocytogenes.

Physiological conditions that could provide maximal rates of autolysis of Listeria monocytogenes were examined. L. monocytogenes was found to be refractory to most treatments that promote rapid autolysis in other bacteria. Best rates of autolysis were obtained after resuspending the cells in Tris-hydrochloride buffer at 37 degrees C with the pH optimum at 8.0. Autolysis was also efficiently promoted by the surfactant Triton X-100. Antibiotics that interfere with the biosynthesis of the cell wall murein (peptidoglycan) caused death of the cells without autolysis after prolonged incubation in the presence of the drug. Only nisin, which has been shown to bind in vitro to the murein precursors lipid I and lipid II brings about autolysis of L. monocytogenes cells, although with slower kinetics than in the case of Tris-HCl and Triton.