Khajuria Atul, Praharaj Ashok Kumar, Kumar Mahadevan, Grover Naveen, Aggarwal Amit
Department of Microbiology, Armed Forces Medical College, Pune, Maharashtra, India.
Indian J Pathol Microbiol. 2014 Jan-Mar;57(1):65-8. doi: 10.4103/0377-4929.130900.
The objective of the following study is to detect genes encoding carbapenem resistance in Klebsiella pneumoniae sepsis outbreak in a neonatal intensive care unit (NICU).
Antibiotic sensitivity test was performed by standard Kirby Bauer disc diffusion technique and minimum inhibitory concentrations of antibiotics was determined by VITEK-2. Polymerase chain reaction (PCR) assays and sequencing was used to determine the presence of beta-lactamase encoding genes. Conjugation experiments were performed to determine the transferability of beta-lactamase. Isolate relatedness were determined by repetitive-element PCR (REP), enterobacterial repetitive intergenic consensus (ERIC) PCR and random amplified polymorphic deoxyribonucleic acid (RAPD).
All the isolates were completely resistant to the second and third generation cephalosporins tested as well as carbapenems. Susceptibility profiling of the isolates indicated that 100% retained susceptibility to tigecycline and colistin. Conjugation experiments indicated that blaNDM-1 was transferable and likely through a plasmid-mediated event. All the isolates showed the presence of blaNDM-1 with co association of blaCTX-M-15. REP-PCR, ERIC-PCR and RAPD revealed a single clonal type circulating in NICU environment.
Co-production of NDM-1 with CTX-M-15 in K. pneumoniae isolates was detected for the first time in our NICU. Transmission of plasmid carrying these resistant genes to other members of Enterobacteriaceae will increase the incidence of multidrug resistance. Early detection of these genes will help in prevention and adequate infection control by limiting the spread of these organisms.
以下研究的目的是在一家新生儿重症监护病房(NICU)的肺炎克雷伯菌败血症暴发中检测编码碳青霉烯耐药性的基因。
采用标准的 Kirby Bauer 纸片扩散法进行抗生素敏感性试验,并用 VITEK-2 测定抗生素的最低抑菌浓度。采用聚合酶链反应(PCR)检测和测序来确定β-内酰胺酶编码基因的存在。进行接合试验以确定β-内酰胺酶的可转移性。通过重复元件 PCR(REP)、肠杆菌重复基因间共有序列(ERIC)PCR 和随机扩增多态性脱氧核糖核酸(RAPD)来确定分离株的相关性。
所有分离株对所检测的第二代和第三代头孢菌素以及碳青霉烯类均完全耐药。分离株的药敏谱表明,100%对替加环素和黏菌素仍敏感。接合试验表明 blaNDM-1 是可转移的,且可能是通过质粒介导的事件。所有分离株均显示存在 blaNDM-1 并与 blaCTX-M-15 共同存在。REP-PCR、ERIC-PCR 和 RAPD 显示在 NICU 环境中有单一克隆型在传播。
在我们的 NICU 首次检测到肺炎克雷伯菌分离株中 NDM-1 与 CTX-M-15 共同产生。携带这些耐药基因的质粒向肠杆菌科其他成员的传播将增加多重耐药的发生率。早期检测这些基因将有助于通过限制这些微生物的传播来预防和进行充分的感染控制。