Phenotype microarray profiling of Staphylococcus aureus menD and hemB mutants with the small-colony-variant phenotype.
Standard biochemical tests have revealed that hemin and menadione auxotrophic Staphylococcus aureus small-colony variants (SCVs) exhibit multiple phenotypic changes. To provide a more complete analysis of the SCV phenotype, two genetically defined mutants with a stable SCV phenotype were comprehensively tested. These mutants, generated via mutations in menD or hemB that yielded menadione and hemin auxotrophs, were subjected to phenotype microarray (PM) analysis of over 1,500 phenotypes (including utilization of different carbon, nitrogen, phosphate, and sulfur sources; growth stimulation or inhibition by amino acids and other nutrients, osmolytes, and metabolic inhibitors; and susceptibility to antibiotics). Compared to parent strain COL, the hemB mutant was defective in utilization of a variety of carbon sources, including Krebs cycle intermediates and compounds that ultimately generate ATP via electron transport. The phenotype of the menD mutant was similar to that of the hemB mutant, but the defects in carbon metabolism were more pronounced than those seen with the hemB mutant. In both mutant strains, hexose phosphates and other carbohydrates that provide ATP in the absence of electron transport stimulated growth. Other phenotypes of SCV mutants, such as hypersensitivity to sodium selenite, sodium tellurite, and sodium nitrite, were also uncovered by the PM analysis. Key results of the PM analysis were confirmed in independent growth studies and by using Etest strips for susceptibility testing. PM technology is a new and efficient technology for assessing cellular phenotypes in S. aureus.
von Eiff
Christof
C
Institute of Medical Microbiology, University Hospital of Münster, Domagkstrasse 10, 48149 Münster, Germany. eiffc@uni-muenster.de
McNamara
Peter
P
Becker
Karsten
K
Bates
Donna
D
Lei
Xiang-He
XH
Ziman
Michael
M
Bochner
Barry R
BR
Peters
Georg
G
Proctor
Richard A
RA
D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002244:Carbon / Q000378:metabolism; D003470:Culture Media; D006427:Hemin / Q000172:deficiency / Q000235:genetics; D008826:Microbial Sensitivity Tests; D010710:Phosphates / Q000378:metabolism; D017670:Sodium Compounds; D013211:Staphylococcus aureus / Q000187:drug effects / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism*; D024483:Vitamin K 3 / Q000378:metabolism
D000900:Anti-Bacterial Agents; D003470:Culture Media; D010710:Phosphates; D017670:Sodium Compounds; D024483:Vitamin K 3; D006427:Hemin; D002244:Carbon