Background: The incidence of Clostridium difficile infection (CDI) has markedly increased over the past decade. Although its epidemiology has been previously investigated in tertiary hospitals, no studies have investigated the prevalence of CDI in county level hospitals in China. Objectives: This study aimed at describing the molecular characteristics of toxigenic C. difficile isolated from a community level hospital and evaluating physicians' knowledge on CDI. Methods: We conducted a 15-month study at a country level hospital to characterize clinical isolates of C. difficile. A total of 61 toxigenic strains were isolated including 54 strains (88.5%), with both tcdA and tcdB genes positive and the remaining positive for the tcdB gene alone. Results: No binary toxin was detected. The toxigenic strains were found to be susceptible to vancomycin and metronidazole and exhibited high levels of resistance to clindamycin, levofloxacin, erythromycin, and ciprofloxacin. The most toxigenic C. difficile isolate was obtained from the gastroenterology and infection ward. Additionally, 13 sequence types (STs) were identified; ST-54 (32.8%), , , and ST-37 (11.5%) were the most common types. Conclusions:The results of the present study indicate that CDI may be a common problem, and large-scale multicenter studies are required to reveal the actual extent of the burden of CDI in county level hospitals.

The emergence of multidrug-resistant Pseudomonas spp. in the clinical settings has heightened public awareness. Here, we described the genomic characteristics of a P. putida isolate co-carrying five β-lactam resistance genes recovered from a urinary tract infection in China. Whole-genome sequencing was performed using Illumina NovaSeq 6000 and Oxford Nanopore MinION platforms. The genome sequence was annotated and further subjected to identify the sequence type (ST), antibiotic resistance and virulence genes. Phylogenetic analysis of 193 P. putida strains stored in NCBI public database based on core genome single nucleotide polymorphism (cgSNP) strategy were also performed and visualized. Our study indicated that P. putida PP_2463 was resistant to a wide range of antimicrobial agents tested, including aminoglycosides, carbapenems and fluoroquinolones. The complete genome sequence of P. putida PP_2463 is made up of one chromosome and two plasmids, which could be assigned to a new sequence type (ST) 148. The co-occurrence of β-lactam resistance genes bla IPM-15 , bla PME-1 , bla CARB-2 , and bla NDM-1 were first identified in P. putida , and a novel β-lactamase gene located in the chromosome were among the antimicrobial resistance genes discovered. The closest relative of P. putida PP_2463 was identified in 2012 from a urine sample in China, with a difference of 143 SNPs. Along with the presence of multiple β-lactamase genes and mobile genetic elements, the multidrug-resistant phenotype suggests a significant potential as an antibiotic resistance reservoir for Pseudomonas spp.

Objective Klebsiella michiganensis is an emerging hospital-acquired bacterial pathogen. However, there is a dearth of knowledge on the antimicrobial resistance and transmission of K. michiganensis . Here, we characterized the microbiological and genomic features of a carbapenem-resistant K. michiganensis strain harboring the bla NDM-1 gene in China. Methods K. michiganensis strain 2563 was recovered from the sputum sample of a hospitalized patient with pulmonary infection. Whole-genome sequencing of K. michiganensis strain 2563 was conducted using both the short-read Illumina and long-read MinION platforms to thoroughly characterize the genetic context of bla NDM -carrying plasmid in K. michiganensis 2563. Furthermore, BacWGSTdb server was utilized to perform in silico multilocus sequence typing (MLST), identify antimicrobial resistance genes, and conduct genomic epidemiological analyses of the closely related isolates deposited in the public database. Results K. michiganensis 2563 was resistant to piperacillin, aztreonam, meropenem, imipenem, amoxicillin-clavulanic acid, ampicillin, cefotaxime, cefazolin, ampicillin/sulbactam, cefepime, piperacillin-tazobactam, and ceftazidime. It belonged to sequence type (ST) 43, and the bla NDM-1 gene was found to be located on the plasmid p2563_NDM (54,035 bp). This plasmid showed remarkable similarity to other bla NDM-1 -encoding plasmids found in various Enterobacterium species in the public database. The occurrence of global ST43 K. michiganensis was primarily sporadic, and the closest relative of K. michiganensis 2563 was another ST43 isolate 12,084 recovered from China in 2013, which differed by 171 SNPs. Conclusion Our study reports the genome characteristics of a carbapenem-resistant K. michiganensis strain carrying the bla NDM-1 gene in China, highlighting the need for ongoing surveillance of this pathogen in clinical settings.

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