Hull S I, Wallace R J, Bobey D G, Price K E, Goodhines R A, Swenson J M, Silcox V A
Am Rev Respir Dis. 1984 Apr;129(4):614-8.
Isolates of the 3 biovariants of Mycobacterium fortuitum exhibited 3 patterns of resistance when tested against 9 aminoglycosides. Examination of cell lysates from the 3 groups revealed 15/15 isolates to contain an aminoglycoside acetyltransferase (AAC) resembling AAC (3)-III or (3)-IV found in bacterial species. The enzyme did not appear to confer resistance, as its activity did not correlate with any pattern of resistance. The DNA extraction revealed plasmids in only 2 of 8 isolates tested, suggesting no relationship of plasmids to intrinsic aminoglycoside resistance or the presence of the AAC. These studies, combined with current knowledge of ribosomal resistance, suggest altered cellular transport or permeability as the mechanism of intrinsic aminoglycoside resistance in this species, although the patterns of resistance are different from those observed in other bacteria with nonenzymatic aminoglycoside resistance. This is the first demonstration of specific aminoglycoside-modifying enzymes among mycobacterial species and the first report of plasmids in M. fortuitum.
偶然分枝杆菌的3个生物变种菌株在针对9种氨基糖苷类药物进行测试时，呈现出3种耐药模式。对这3组菌株的细胞裂解物进行检测发现，15/15的菌株含有一种氨基糖苷乙酰转移酶（AAC），类似于在细菌物种中发现的AAC(3)-III或(3)-IV。该酶似乎并未赋予耐药性，因为其活性与任何耐药模式均无关联。DNA提取显示，在测试的8株菌株中仅有2株含有质粒，这表明质粒与固有氨基糖苷类耐药性或AAC的存在无关。这些研究，结合目前对核糖体耐药性的认识，表明细胞转运或通透性改变是该物种固有氨基糖苷类耐药性的机制，尽管其耐药模式与在其他具有非酶促氨基糖苷类耐药性的细菌中观察到的不同。这是分枝杆菌物种中特定氨基糖苷类修饰酶的首次证明，也是偶然分枝杆菌中质粒的首次报道。
