Abstract
Carbapenem-resistant Klebsiella pneumonia (CRKP) infections has become a concerning threat. However, knowledge regarding the characteristics of intestinal CRKP isolates is limited. This study aimed to investigate and compare the clinical, virulence and molecular epidemiological characteristics of intestinal colonization and extraintestinal infections CRKP strains. The clinical characteristics were investigated retrospectively. Polymerase chain reaction was used to investigate the capsular serotype, virulence genes and carbapenemase genes. Capsular polysaccharide quantification assay, serum resistance assay, biofilm formation assay, and infection model of Galleria mellonella larvae were performed to compare the virulence and pathogenicity. Besides, multilocus-sequence-typing (MLST) and pulsed-field-gel-electrophoresis (PFGE) were conducted to explore the homology of intestinal CRKP isolates. A total of 54 intestinal CRKP isolates were included. The main capsular serotypes were K14, K64, and K19. C-reactive protein and the proportion of ICU isolation of the infection group were significantly higher than that of the colonization group (P < 0.05). The carrier rates of various virulence genes of CRKP in the infection group were mostly higher than those in the colonization group, wherein the carrier rates of peg-344 and rmpA were significantly different (P < 0.05). There was no significant difference in capsular polysaccharides, antiserum ability, biofilm formation ability between the two group (P > 0.05), but the lethality of the infection group to Galleria mellonella was significantly higher than that of the colonization group (P < 0.05). The MLST categorized the 54 isolates into 13 different sequence types. PFGE revealed that homology among the 54 CRKP strains was <80%. This study suggested that the CRKP strains in the infection group had higher virulence than those in the colonization group. The development of CRKP isolates colonizing in the intestine should be addressed in future clinical surveillance.
Highlights
With the widespread use of carbapenems, the emergence of carbapenem-resistant Klebsiella pneumoniae (CRKP) has been increasingly reported worldwide [1,2,3]
The results showed that the median age of patients with intestinal Carbapenem-resistant Klebsiella pneumonia (CRKP) was 59-year-old, and males accounted for 61.1%. 51 cases (94.4%) suffered from concomitant diseases, including 12 (22.2%) diabetes, 15 (27.8%) cardiovascular and cerebrovascular diseases, 14 (25.9%) renal insufficiency, 24 (44.4%) liver insufficiency, 5 (9.3%) trauma and so on
In order to understand the difference between intestinal colonization and causing-extraintestinal infections CRKP strains, we investigated and compared the clinical and microbiological characteristics of intestinal CRKP isolates
Summary
With the widespread use of carbapenems, the emergence of carbapenem-resistant Klebsiella pneumoniae (CRKP) has been increasingly reported worldwide [1,2,3]. The intestinal tract of hospitalized patients is an enormous repository of antibiotic-resistant bacteria [6]. Antibiotic-resistant bacteria can colonize in the intestine tract, and transfer to other tissues through intestinal metastasis, leading to serious extraintestinal infections [7], which will be an important risk factor for systemic infection in-hospital death of patients. Studies have shown that not all Klebsiella pneumoniae (K. pneumoniae) colonized in the intestine could cause further infection [8], and the majority of patients with colonized pathogens did not suffer from infection for several years or even decades [9]. The gene fimH and mrkD promote bacterial adhesion to host tissues and organs by encoding type 1 and type 3 fimbriae of K. pneumoniae, leading to bacterial colonization and pathogenicity. MrkD can promote the development of biofilms, which improves the bacteria’s resistance to host defense and antibiotics [16]
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