Antibacterial activity of Acinetobacter baumannii phage ϕAB2 endolysin (LysAB2) against both gram-positive and gram-negative bacteria.
To investigate the nature and origin of the antibacterial activity of the lytic phage ϕAB2 toward Acinetobacter baumannii, we successfully isolated and characterized a novel phage lysozyme (endolysin) from ϕAB2 and named it LysAB2. To analyze antibacterial activity of LysAB2, the complete LysAB2 and two deletion derivatives were constructed, purified and characterized. Zymographic assays showed that only the intact LysAB2 could lyse the peptidoglycan of A. baumannii and the Staphylococcus aureus cell wall. Antibacterial analysis also showed that only the intact LysAB2 retained the complete bactericidal activity. When applied exogenously, LysAB2 exhibited a broad bacteriolytic activity against a number of Gram-negative and Gram-positive bacteria. Thermostability assays indicated that LysAB2 was stable at 20∼40 °C. Its optimal pH was 6.0, and it was active from pH 4 to 8. Scanning electron microscopy revealed that exposure to 500 μgml(-1) LysAB2 for up to 60 min caused a remarkable modification of the cell shape of the bacteria. Treating bacteria with LysAB2 clearly enhanced permeation of the bacterial cytoplasmic membrane. These results indicate that LysAB2 is an effective lysozyme against bacteria, and they suggest that it is a good candidate for a therapeutic/disinfectant agent to control nosocomial infections caused by multiple drug-resistant bacteria.
Department of Laboratory Medicine and Biotechnology, Tzu Chi University, Hualien 970, Taiwan.
Meng-Jiun
MJ
Lai
Nien-Tsung
NT
Lin
Anren
A
Hu
Po-Chi
PC
Soo
Li-Kuang
LK
Chen
Long-Hui
LH
Chen
Kai-Chih
KC
Chang
D040981:Acinetobacter baumannii / Q000187:drug effects / Q000254:growth & development* / Q000821:virology*; D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001435:Bacteriophages / Q000201:enzymology*; D002473:Cell Wall / Q000187:drug effects; D024901:Drug Resistance, Multiple, Bacterial; D010450:Endopeptidases / Q000494:pharmacology*; D004926:Escherichia coli / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D006094:Gram-Positive Bacteria / Q000187:drug effects* / Q000254:growth & development; D008969:Molecular Sequence Data; D010457:Peptidoglycan / Q000378:metabolism; D010957:Plasmids / Q000235:genetics; D013211:Staphylococcus aureus / Q000187:drug effects / Q000254:growth & development
D000900:Anti-Bacterial Agents; D010457:Peptidoglycan; D010450:Endopeptidases; C001143:endolysin