Tamma Pranita D, Sharara Sima L, Pana Zoi D, Amoah Joe, Fisher Stephanie L, Tekle Tsigereda, Doi Yohei, Simner Patricia J
Department of Pediatrics, The Johns Hopkins University School of Medicine, Baltimore, Maryland.
Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland.
Open Forum Infect Dis. 2019 Aug 11;6(8):ofz353. doi: 10.1093/ofid/ofz353.
Knowledge of whether Enterobacterales are not susceptible to ceftriaxone without understanding the underlying resistance mechanisms may not be sufficient to direct appropriate treatment decisions. As an example, extended-spectrum β-lactamase (ESBL)-producing organisms almost uniformly display non-susceptibility to ceftriaxone. Regardless of susceptibility to piperacillin-tazobactam or cefepime, carbapenem antibiotics are the treatment of choice for invasive infections. No such guidance exists for ceftriaxone non-susceptible organisms with mechanisms other than ESBL production. We sought to investigate the molecular epidemiology of ceftriaxone non-susceptible Enterobacterales.
All consecutive Escherichia coli, Klebsiellapneumoniae, Klebsiella oxytoca, or Proteus mirabilis clinical isolates with ceftriaxone MICs of ≥2 mcg/mL from unique patients at a United States hospital over an 8-month period were evaluated for β-lactamase genes using a DNA microarray-based assay.
Of 1929 isolates, 482 (25%) had ceftriaxone MICs of ≥2 mcg/mL and were not resistant to any carbapenem antibiotics. Of the 482 isolates, ESBL (blaCTX-M, blaSHV, blaTEM) and/or plasmid-mediated ampC (p-ampC) genes were identified in 376 (78%). ESBL genes were identified in 310 (82.4%), p-ampC genes in 2 (0.5%), and both ESBL and p-ampC genes in 64 (17.0%) of the 376 organisms. There were 211 (56%), 120 (32%), 41 (11%), and 4 (1%) isolates with 1, 2, 3, or 4 or more ESBL or p-ampC genes. The most common ESBL genes were of the blaCTX-M-1 group (includes blaCTX-M-15) and the most common p-ampC gene was the blaCMY-2.
There is considerable diversity in the molecular epidemiology of ceftriaxone non-susceptible Enterobacterales. An understanding of this diversity can improve antibiotic decision-making.
在不了解潜在耐药机制的情况下，仅知道肠杆菌科细菌对头孢曲松不敏感可能不足以指导恰当的治疗决策。例如，产超广谱β-内酰胺酶（ESBL）的菌株几乎都对头孢曲松不敏感。无论对哌拉西林-他唑巴坦或头孢吡肟是否敏感，碳青霉烯类抗生素都是侵袭性感染的治疗选择。对于除产ESBL以外其他机制导致对头孢曲松不敏感的菌株，尚无此类指导。我们试图调查对头孢曲松不敏感的肠杆菌科细菌的分子流行病学。
对一家美国医院8个月期间来自不同患者的所有连续分离的大肠埃希菌、肺炎克雷伯菌、产酸克雷伯菌或奇异变形杆菌临床分离株进行评估，这些分离株对头孢曲松的最低抑菌浓度（MIC）≥2 mcg/mL，采用基于DNA微阵列的检测方法检测β-内酰胺酶基因。
在1929株分离株中，482株（25%）对头孢曲松的MIC≥2 mcg/mL且对任何碳青霉烯类抗生素均不耐药。在这482株分离株中，376株（78%）鉴定出ESBL（blaCTX-M、blaSHV、blaTEM）和/或质粒介导的AmpC（p-ampC）基因。在376株菌中，310株（82.4%）鉴定出ESBL基因，2株（0.5%）鉴定出p-ampC基因，64株（17.0%）同时鉴定出ESBL和p-ampC基因。有211株（56%）、120株（32%）、41株（11%）和4株（1%）分离株分别携带1、2、3或4个及以上ESBL或p-ampC基因。最常见ESBL基因属于blaCTX-M-1组（包括blaCTX-M-15），最常见的p-ampC基因是blaCMY-2。
对头孢曲松不敏感的肠杆菌科细菌的分子流行病学存在相当大的多样性。了解这种多样性有助于改善抗生素决策。
