Antimicrobial resistance, virulence genes profiles and molecular epidemiology of carbapenem-resistant Klebsiella pneumoniae strains from captive giant pandas (Ailuropoda melanoleuca).

Abstract

Background: Carbapenem-resistant Klebsiella pneumoniae (CRKP) increases the difficulty of clinical treatment of giant pandas. This study aimed to investigate the antibiotic susceptibility, antibiotic resistance genes (ARGs), mobile genetic elements (MGEs), virulence genes, and molecular epidemiology of CRKP strains isolated from giant pandas. A total of 187 nonduplicated Klebsiella pneumoniae (KP) isolates were collected from fresh feces of captive giant pandas at the Chengdu Research Base of Giant Panda Breeding. Then CRKP were isolated and identified through carbapenase Carba NP assay. Subsequently, the antimicrobial susceptibility testing and antibiotic resistance genes of CRKP isolates were studied by disk diffusion (K-B) and HT-qPCR, respectively. Then both the MGEs and virulence genes of CRKP isolates were analyzed by PCR. In addition, molecular epidemiology was analyzed among the CRKP strains using pulsed-field gel electrophoresis (PFGE) and multi-locus sequence typing (MLST).

Results: Eight strains of CRKP (4.5%) were isolated and identified among the 187 KP strains, and seven of eight CRKP strains both exhibited resistance to imipenem, while one strain showed resistance to meropenem, and one demonstrated multiple resistance; eight CRKP strains carried a large amount of ARGs, among which amp_C/bla_DHA, bla_SHV-01, bla_SHV-02, tet_B-01, tet_B-02, tet_C-01, and tet_C-02 were the most abundant. The MGEs analysis revealed the presence of intI1 in all strains, while the detection rates of other MGEs varied, and strain 24 exhibited the highest diversity of MGE species. Seven virulence genes, including wabG, uge, ycf, entB, kpn, alls, and wcaG, showed positive results with different proportions across the strains. In addition, PFGE patterns indicated a high level of genetic diversity among the CRKP strains. MLST analysis classified the strains into different sequence types (STs).

Conclusions: This study highlighted the diversity of CRKP strains isolated from giant panda feces, which exhibited varying levels of antibiotic resistance along with multiple ARGs, MGEs and virulence genes present. These findings emphasized the importance of monitoring and researching antibiotic resistance within wildlife populations to protect the health status of these conservation dependent animals.