Stock Ingo, Burak Sonja, Sherwood Kimberley Jane, Gruger Thomas, Wiedemann Bernd
Institut für Medizinische Mikrobiologie und Immunologie, Pharmazeutische Mikrobiologie, Meckenheimer Allee 168, University of Bonn, D-53115 Bonn, Germany.
J Antimicrob Chemother. 2003 Apr;51(4):865-85. doi: 10.1093/jac/dkg156. Epub 2003 Mar 13.
The natural susceptibility to 71 antibiotics of 104 Serratia strains of Serratia ficaria (n = 15), Serratia fonticola (n = 18), Serratia odorifera (n = 16), Serratia plymuthica (n = 32) and Serratia rubidaea (n = 23) was examined. MICs were determined using a microdilution procedure in IsoSensitest broth for all the strains and in cation-adjusted Mueller-Hinton broth for some strains. With few exceptions, all species tested were uniformly naturally resistant to penicillin G, oxacillin, cefazolin, cefuroxime, all tested macrolides, lincosamides, streptogramins, glycopeptides, fusidic acid and rifampicin, and naturally sensitive to several aminoglycosides, piperacillin, piperacillin/tazobactam, carbapenems, some cephalosporins, fluoroquinolones and folate-pathway inhibitors. Major species-related differences in natural susceptibility affecting clinical assessment criteria were seen with tetracyclines, some aminoglycosides, aminopenicillins, ticarcillin, cefaclor, loracarbef, cefoxitin, pipemidic acid, chloramphenicol, nitrofurantoin and fosfomycin. Differences in susceptibility dependent on the medium were seen with macrolides, tetracycline, fosfomycin and some beta-lactams. The natural antibiotic susceptibility patterns suggest novel species-specific mechanisms of antibiotic resistance. Uncharacterized species-specific aminoglycoside-modifying enzymes and multidrug efflux systems affecting tetracyclines, quinolones and chloramphenicol are probably responsible for some of the phenotypes observed. The natural amoxicillin sensitivity of several strains of some species combined with natural resistance to some narrow-spectrum cephalosporins indicate the expression of naturally occurring beta-lactamases with unique substrate profiles. beta-Lactamases of representative strains of each species were characterized phenotypically and genotypically. It was shown that all species expressed naturally occurring AmpC beta-lactamases and, with respect to S. fonticola, also a species-specific class A beta-lactamase. Inducibility of these enzymes was shown in all species with the exception of S. rubidaea and four of five strains of S. plymuthica.
检测了104株无花果沙雷氏菌（n = 15）、丰蒂科拉沙雷氏菌（n = 18）、气味沙雷氏菌（n = 16）、普城沙雷氏菌（n = 32）和深红沙雷氏菌（n = 23）对71种抗生素的天然敏感性。对所有菌株采用微量稀释法在异感测试肉汤中测定最低抑菌浓度（MIC），对部分菌株在阳离子调节的 Mueller-Hinton 肉汤中测定。除少数例外，所有测试的菌种对青霉素G、苯唑西林、头孢唑林、头孢呋辛、所有测试的大环内酯类、林可酰胺类、链阳菌素类、糖肽类、夫西地酸和利福平均天然耐药，对几种氨基糖苷类、哌拉西林、哌拉西林/他唑巴坦、碳青霉烯类、一些头孢菌素类、氟喹诺酮类和叶酸途径抑制剂天然敏感。在四环素、一些氨基糖苷类、氨基青霉素、替卡西林、头孢克洛、氯碳头孢、头孢西丁、吡哌酸、氯霉素、呋喃妥因和磷霉素方面，观察到了影响临床评估标准的主要菌种相关天然敏感性差异。在大环内酯类、四环素、磷霉素和一些β-内酰胺类药物方面，观察到了依赖培养基的敏感性差异。天然抗生素敏感性模式提示了新的菌种特异性抗生素耐药机制。未鉴定的菌种特异性氨基糖苷类修饰酶和影响四环素、喹诺酮类和氯霉素的多药外排系统可能是观察到的一些表型的原因。一些菌种的几株菌株对阿莫西林天然敏感，同时对一些窄谱头孢菌素天然耐药，这表明存在具有独特底物谱的天然β-内酰胺酶。对每个菌种的代表性菌株的β-内酰胺酶进行了表型和基因型鉴定。结果表明，所有菌种均表达天然存在的AmpC β-内酰胺酶，就丰蒂科拉沙雷氏菌而言，还表达一种菌种特异性A类β-内酰胺酶。除深红沙雷氏菌和五株普城沙雷氏菌中的四株外，所有菌种中这些酶均具有可诱导性。
