广西医学

目的基于联合药敏试验筛选携带肺炎克雷伯菌碳青霉烯酶2(KPC⁃2）、新德里金属⁃β⁃内酰胺酶（NDM）⁃1、NDM⁃5‌基因的耐碳青霉烯类肺炎克雷伯菌（CRKP）的潜在有效联合用药方案。方法收集临床分离的91株非重复性CRKP，选取当地流行菌株，即携带KPC⁃2、NDM⁃1及NDM⁃5基因的CRKP各20株，通过PCR扩增联合DNA测序检测常见碳青霉烯酶基因，并行多位点序列分型（MLST）。采用微量肉汤稀释法进行药敏试验，并采用纸片扩散法以替加环素（TGC）或头孢他啶/阿维巴坦（CZA）为中心，分别联合氨曲南（ATM）、左氧氟沙星、阿米卡星、头孢哌酮/舒巴坦（SCF）、磷霉素进行联合药敏试验。结果 MLST结果显示，携带KPC⁃2基因的CRKP以ST11型为主（16株，80%），携带NDM⁃1基因的CRKP以ST17型为主（11株，55%），携带NDM⁃5基因的CRKP以ST15型为主（14株，70%）。携带KPC⁃2基因的CRKP对喹诺酮类药物的耐药率高于携带NDM⁃1或NDM⁃5基因的CRKP；携带NDM⁃1基因的CRKP对氨基糖苷类药物的耐药率低于携带KPC⁃2或NDM⁃5基因的CRKP；携带NDM⁃5基因的CRKP对TGC和氯霉素的耐药率高于携带KPC⁃2或NDM⁃1基因的CRKP。联合药敏试验结果显示，以TGC为中心的联合方案对60株CRKP仅显示相加或无关作用，均未表现出协同或拮抗作用；以CZA为中心的联合方案对所有CRKP均未表现出拮抗作用，CZA联合ATM对携带NDM⁃1或NDM⁃5基因的CRKP的协同率为100.0%，CZA联合ATM和CZA联合SCF对携带KPC⁃2基因的CRKP的协同率均为100.0%。结论本地区CRKP感染病例以携带KPC⁃2、NDM⁃1和NDM⁃5基因的菌株为主，不同类型CRKP对抗菌药物的体外敏感性存在差异。不同的联合用药方案对不同类型CRKP的体外抗菌效果不同：对于产KPC⁃2的CRKP感染患者，推荐选用CZA联合ATM或CZA联合SCF的治疗方案；对于产NDM⁃1或NDM⁃5的CRKP感染患者，建议选用CZA联合ATM的治疗方案。

Objective To screen the potentially effective combination medication regimens against carbapenem⁃resistant Klebsiella pneumoniae (CRKP) carrying Klebsiella pneumoniae carbapenemase 2 (KPC⁃2), New Delhi metallo⁃beta⁃lactamase (NDM)⁃1, and NDM⁃5 genes based on combined drug susceptible test. Methods A total of 91 non⁃duplicate CRKP strains were isolated from clinic. The local prevalent strains were selected, namely, 20 strains of each CRKP were carried by genes of KPC⁃2, NDM⁃1, and NDM⁃5. Common carbapenemase genes were detected by PCR amplification combined with DNA sequencing, and multilocus sequence typing (MLST) was performed. Drug susceptible test was performed using the broth microdilution method. Disk diffusion method was taken tigecycline (TGC) or ceftazidime/avibactam (CZA) as central drugs, and combined drug susceptible test was performed combined with aztreonam (ATM), levofloxacin, amikacin, cefoperazone/sulbactam (SCF), and fosfomycin, respectively. Results MLST results revealed that CRKP strains carrying KPC⁃2 gene were mainly of the ST11 type (16 strains, 80%), carrying NDM⁃1 gene were mainly of the ST17 type (11 strains, 55%), carrying NDM⁃5 gene were mainly of the ST15 type (14 strains, 70%). The resistance rate to quinolones was higher in CRKP carrying KPC⁃2 gene compared to CRKP carrying NDM⁃1 or NDM⁃5 genes. The resistance rate to aminoglycosides was lower in CRKP carrying NDM⁃1 gene compared to CRKP carrying KPC⁃2 and NDM⁃5 genes. The resistance rates to TGC and chloramphenicol were higher in CRKP carrying NDM⁃5 gene compared to CRKP carrying KPC⁃2 or NDM⁃1 genes. Combined drug susceptible test results indicated that in TGC⁃centered combination regimens, all 60 CRKP strains exhibited only additive or indifferent effects, with no synergistic or antagonistic effects observed. In CZA⁃centered combination regimens, no antagonistic effects were observed in any CRKP strains. The synergy rate of CZA combined with ATM against CRKP carrying NDM⁃1 or NDM⁃5 genes was 100.0%, and the synergy rates of CZA combined with ATM and CZA combined with SCF against CRKP carrying KPC⁃2 gene were also 100.0%. Conclusion The CRKP infection cases in this region are mainly caused by strains carrying KPC⁃2, NDM⁃1 and NDM⁃5 genes. Different types of CRKP exhibit varying in vitro sensitivity to antibiotics. Different combination medication regimens have different in vitro antibacterial effects on different types of CRKP: for patients with CRKP infection caused by KPC⁃2 producers, the therapeutic regimens of CZA combined with ATM or CZA combined with SCF are recommended; furthermore, for patients with CRKP infections that produce NDM⁃1 or NDM⁃5, it is recommended to use the therapeutic regimen of CZA combined with ATM.