Institute of Medical Microbiology, Semmelweis University, Nagyvárad tér 4., 1089, Budapest, Hungary.
Department of Bacteriology, Mycology and Parasitology, National Public Health Centre, Albert Flórián út 2-6., 1097, Budapest, Hungary.
Sci Rep. 2021 Mar 18;11(1):6335. doi: 10.1038/s41598-021-85766-6.
Great efforts have been made to limit the transmission of carbapenemase-producing Enterobacteriaceae (CPE), however, the intestinal reservoir of these strains and its modulation by various antibiotics remain largely unexplored. Our aim was to assess the effects of antibiotic administration (ampicillin, ceftazidime, ciprofloxacin) on the establishment and elimination of intestinal colonization with a CTX-M-15 ESBL and OXA-162 carbapenemase producing Klebsiella pneumoniae ST15 (KP5825) in a murine (C57BL/6 male mice) model. Whole genome sequencing of KP5825 strain was performed on an Illumina MiSeq platform. Conjugation assays were carried out by broth mating method. In colonization experiments, 5 × 10 CFU of KP5825 was administered to the animals by orogastric gavage, and antibiotics were administered in their drinking water for two weeks and were changed every day. The gut colonization rates with KP5825 were assessed by cultivation and qPCR. In each of the stool samples, the gene copy number of bla and bla were determined by qPCR. Antibiotic concentrations in the stool were determined by high pressure liquid chromatography and a bioanalytical method. The KP5825 contained four different plasmid replicon types, namely IncFII(K), IncL, IncFIB and ColpVC. IncL (containing the bla resistance gene within a Tn1991.2 genetic element) and IncFII(K) (containing the bla resistance gene) plasmids were successfully conjugated. During ampicillin and ceftazidime treatments, colonization rate of KP5825 increased, while, ciprofloxacin treatments in both concentrations (0.1 g/L and 0.5 g/L) led to significantly decreased colonization rates. The gene copy number bla correlated with K. pneumoniae in vivo, while a major elevation was observed in the copy number of bla from the first day to the fifteenth day in the 0.5 g/L dose ceftazidime treatment group. Our results demonstrate that commonly used antibiotics may have diverse impacts on the colonization rates of intestinally-carried CPE, in addition to affecting the gene copy number of their resistance genes, thus facilitating their stable persistance and dissemination.
尽管已经做出了巨大努力来限制碳青霉烯酶产生肠杆菌科（CPE）的传播，但这些菌株的肠道储库及其被各种抗生素的调节作用在很大程度上仍未得到探索。我们的目的是评估抗生素（氨苄西林、头孢他啶、环丙沙星）给药对 CTX-M-15 ESBL 和 OXA-162 碳青霉烯酶产生肺炎克雷伯菌 ST15（KP5825）在小鼠（C57BL/6 雄性小鼠）模型中肠道定植和消除的影响。使用 Illumina MiSeq 平台对 KP5825 菌株进行全基因组测序。通过肉汤交配方法进行接合试验。在定植实验中，通过口胃管给予动物 5×10 CFU 的 KP5825，并用抗生素处理饮用水两周，每天更换。通过培养和 qPCR 评估 KP5825 的肠道定植率。在每个粪便样本中，通过 qPCR 确定 bla 和 bla 的基因拷贝数。通过高压液相色谱法和生物分析方法确定粪便中的抗生素浓度。KP5825 包含四种不同的质粒复制子类型，即 IncFII（K）、IncL、IncFIB 和 ColpVC。成功接合了携带 bla 耐药基因的 IncL（包含在 Tn1991.2 遗传元件内的 bla 耐药基因）和 IncFII（K）（包含 bla 耐药基因）质粒。在氨苄西林和头孢他啶治疗期间，KP5825 的定植率增加，而在两种浓度（0.1 g/L 和 0.5 g/L）的环丙沙星治疗中，定植率显著降低。基因 bla 拷贝数与体内肺炎克雷伯菌相关，而在 0.5 g/L 头孢他啶治疗组中，从第 1 天到第 15 天，bla 基因的拷贝数显著增加。我们的结果表明，常用抗生素可能对肠道携带的 CPE 的定植率产生不同的影响，除了影响其耐药基因的基因拷贝数外，还促进其稳定的持久性和传播。
