An abnormal multidrug-resistant and hypervirulent Klebsiella pneumoniae clinical isolate without rmpA or rmpA2

Klebsiella pneumoniae is a notorious opportunistic pathogen, especially hypervirulent K. pneumoniae (hvKp). Fortunately, most classical hvKp strains are antibiotic-susceptible. However, in recent years, reports of multidrug-resistant hvKp (MDR-hvKp) have increased dramatically, threatening the health and safety of people worldwide. Here, we report the discovery of MDR-hvKp without rmpA and rmpA2 in a 92-year-old patient with chronic obstructive pulmonary disease. The patient died on the eighth day of hospitalization. Phenotyping experiments and whole-genome sequencing of K. pneumoniae isolate 21072329 isolated from the patient’s sputum were performed. Moreover, 21072329 belongs to ST11-KL47 MDR-hvKp, which was highly lethal to Galleria mellonella. Meanwhile, 21072329 had a strong viscosity, and it was difficult to completely centrifuge it; 21072329 carried ESBL genes (bla_CTX-M-65, bla_SHV-158, and bla_TEM-1) and a carbapenemase gene (bla_KPC-2), and it was resistant to carbapenem antibiotics and third- and fourth-generation cephalosporins. Although 21072329 had the characteristics of hvKp, rmpA and rmpA2 could not be found in its genome; it also only carried a siderophore of yersiniabactin. This may indicate that other hypervirulence factors promote the formation of hvKp. MDR-hvKp has already brought an enormous burden to global medical care, and those carrying unknown hypervirulence factors are new threats, so urgent prevention and control with research are urgently needed.