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Abstract：
UNASSIGNED: Ceftazidime/avibactam (CZA) is indicated against multidrug-resistant Pseudomonas aeruginosa, particularly those that are carbapenem resistant. CZA resistance in P. aeruginosa producing PER, a class A extended-spectrum β-lactamase, has been well documented in vitro. However, data regarding clinical isolates are scarce. Our aim was to analyze the contribution of PER to CZA resistance in non-carbapenemase-producing P. aeruginosa clinical isolates that were ceftazidime and/or carbapenem non-susceptible.
UNASSIGNED: Antimicrobial susceptibility was determined through agar dilution and broth microdilution, while bla PER gene was screened through PCR. All PER-positive isolates and five PER-negative isolates were analyzed through Whole Genome Sequencing. The mutational resistome associated to CZA resistance was determined through sequence analysis of genes coding for PBPs 1b, 3 and 4, MexAB-OprM regulators MexZ, MexR, NalC and NalD, AmpC regulators AmpD and AmpR, and OprD porin. Loss of bla PER-3 gene was induced in a PER-positive isolate by successive passages at 43°C without antibiotics.
UNASSIGNED: Twenty-six of 287 isolates studied (9.1%) were CZA-resistant. Thirteen of 26 CZA-resistant isolates (50%) carried bla PER. One isolate carried bla PER but was CZA-susceptible. PER-producing isolates had significantly higher MICs for CZA, amikacin, gentamicin, ceftazidime, meropenem and ciprofloxacin than non-PER-producing isolates. All PER-producing isolates were ST309 and their bla PER-3 gene was associated to ISCR1, an insertion sequence known to mobilize adjacent DNA. PER-negative isolates were classified as ST41, ST235 (two isolates), ST395 and ST253. PER-negative isolates carried genes for narrow-spectrum β-lactamases and the mutational resistome showed that all isolates had one major alteration in at least one of the genes analyzed. Loss of bla PER-3 gene restored susceptibility to CZA, ceftolozane/tazobactam and other β-lactamsin the in vitro evolved isolate.
UNASSIGNED: PER-3-producing ST309 P. aeruginosa is a successful multidrug-resistant clone with blaPER-3 gene implicated in resistance to CZA and other β-lactams.
UNASSIGNED: Antimicrobial susceptibility was determined through agar dilution and broth microdilution, while bla PER gene was screened through PCR. All PER-positive isolates and five PER-negative isolates were analyzed through Whole Genome Sequencing. The mutational resistome associated to CZA resistance was determined through sequence analysis of genes coding for PBPs 1b, 3 and 4, MexAB-OprM regulators MexZ, MexR, NalC and NalD, AmpC regulators AmpD and AmpR, and OprD porin. Loss of bla PER-3 gene was induced in a PER-positive isolate by successive passages at 43°C without antibiotics.
UNASSIGNED: Twenty-six of 287 isolates studied (9.1%) were CZA-resistant. Thirteen of 26 CZA-resistant isolates (50%) carried bla PER. One isolate carried bla PER but was CZA-susceptible. PER-producing isolates had significantly higher MICs for CZA, amikacin, gentamicin, ceftazidime, meropenem and ciprofloxacin than non-PER-producing isolates. All PER-producing isolates were ST309 and their bla PER-3 gene was associated to ISCR1, an insertion sequence known to mobilize adjacent DNA. PER-negative isolates were classified as ST41, ST235 (two isolates), ST395 and ST253. PER-negative isolates carried genes for narrow-spectrum β-lactamases and the mutational resistome showed that all isolates had one major alteration in at least one of the genes analyzed. Loss of bla PER-3 gene restored susceptibility to CZA, ceftolozane/tazobactam and other β-lactamsin the in vitro evolved isolate.
UNASSIGNED: PER-3-producing ST309 P. aeruginosa is a successful multidrug-resistant clone with blaPER-3 gene implicated in resistance to CZA and other β-lactams.
摘要：
■头孢他啶/阿维巴坦（CZA）适用于多重耐药铜绿假单胞菌，特别是那些耐碳青霉烯的。铜绿假单胞菌产生PER的CZA抗性，A类广谱β-内酰胺酶,已经在体外有很好的记录。然而,关于临床分离株的数据很少.我们的目的是分析在头孢他啶和/或碳青霉烯类非敏感的非产碳青霉烯酶铜绿假单胞菌临床分离株中PER对CZA耐药性的贡献。
■通过琼脂稀释和肉汤微量稀释确定抗微生物剂敏感性，同时通过PCR筛选blaPER基因。通过全基因组测序分析所有PER阳性分离株和五个PER阴性分离株。通过编码PBPs1b的基因序列分析，确定了与CZA抗性相关的突变抗性组，3和4，MexAB-OprM调节器MexZ，MexR,NalC和NalD,AmpC调节器AmpD和AmpR，和OprDporin.在PER阳性分离物中通过在43°C下在无抗生素的情况下连续传代诱导blaPER-3基因的丢失。
■所研究的287个分离株中有26个（9.1％）具有CZA抗性。26株CZA抗性分离株中有13株(50%)携带blaPER。一种分离物携带blaPER，但对CZA敏感。产生PER的分离株对CZA的MIC显著较高，阿米卡星，庆大霉素,头孢他啶,美罗培南和环丙沙星比不产生PER的分离株。所有产生PER的分离株都是ST309，它们的blaPER-3基因与ISR1相关，ISR1是已知可动员相邻DNA的插入序列。PER阴性分离株分为ST41，ST235（两个分离株），ST395和ST253。PER阴性分离株携带窄谱β-内酰胺酶的基因，突变抗性组显示所有分离株在至少一个分析的基因中都有一个重大改变。blaPER-3基因的缺失恢复了对CZA的易感性，头孢洛赞/他唑巴坦和其他β-内酰胺素是体外进化的分离株。
■产生PER-3的ST309铜绿假单胞菌是一个成功的多药耐药克隆，其blaPER-3基因涉及对CZA和其他β-内酰胺的抗性。
■通过琼脂稀释和肉汤微量稀释确定抗微生物剂敏感性，同时通过PCR筛选blaPER基因。通过全基因组测序分析所有PER阳性分离株和五个PER阴性分离株。通过编码PBPs1b的基因序列分析，确定了与CZA抗性相关的突变抗性组，3和4，MexAB-OprM调节器MexZ，MexR,NalC和NalD,AmpC调节器AmpD和AmpR，和OprDporin.在PER阳性分离物中通过在43°C下在无抗生素的情况下连续传代诱导blaPER-3基因的丢失。
■所研究的287个分离株中有26个（9.1％）具有CZA抗性。26株CZA抗性分离株中有13株(50%)携带blaPER。一种分离物携带blaPER，但对CZA敏感。产生PER的分离株对CZA的MIC显著较高，阿米卡星，庆大霉素,头孢他啶,美罗培南和环丙沙星比不产生PER的分离株。所有产生PER的分离株都是ST309，它们的blaPER-3基因与ISR1相关，ISR1是已知可动员相邻DNA的插入序列。PER阴性分离株分为ST41，ST235（两个分离株），ST395和ST253。PER阴性分离株携带窄谱β-内酰胺酶的基因，突变抗性组显示所有分离株在至少一个分析的基因中都有一个重大改变。blaPER-3基因的缺失恢复了对CZA的易感性，头孢洛赞/他唑巴坦和其他β-内酰胺素是体外进化的分离株。
■产生PER-3的ST309铜绿假单胞菌是一个成功的多药耐药克隆，其blaPER-3基因涉及对CZA和其他β-内酰胺的抗性。
