Abstract
Background:
Raoultella planticola is an uncommon gram-negative organism found in the environment.
Patients and Methods:
The patient, an 81-year-old female who had undergone total cystectomy and bilateral ureteral stoma surgery, presented to the hospital with a fever. It was determined that Raoultella planticola was responsible for the bacteremia.
Results:
Rapid identification of bacteria using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) in blood culture samples and appropriate antibacterial treatment was begun and the patient was discharged three days later.
Conclusions:
This case emphasizes the presence of a rare pathogen as the cause of bacteremia and underscores the importance of utilizing rapid methods for bacterial identification to establish an accurate diagnosis.
R
Case Presentation
An 81-year-old female who had no history of diabetes mellitus or hypertension who was diagnosed with a bladder tumor underwent transurethral plasma resection of the tumor in the urology department of Suzhou Ninth Hospital affiliated with Soochow University. The post-operative pathology revealed grade 2 transitional cell carcinoma of the bladder. Eight months later, total cystectomy and bilateral ureteral stoma were performed for recurrent bladder cancer in the Department of Urology. The post-operative pathology revealed invasive urothelial carcinoma of the bladder, which had invaded the entire wall. The patient made a good recovery with no complications occurring.
After four weeks, the patient was sent to the emergency department with a sudden high fever, up to 41°C, accompanied by convulsions. Abscesses were not detected in any other organs based on the computed tomography scans of the chest and abdomen. Laboratory tests revealed the following: urine biochemistry revealed positive nitrites (normal: negative) and moderate leukocyte esterase (normal: negative). White blood cell count, 12.27 × 109/L with 97.1% neutrophils (normal, 4.00–10.00 × 109]/L with 50%–70% neutrophils); platelet count, 229 × 109/L (normal, 100–300 × 109)/L); and C-reactive protein, 14.80 mg/L (normal, 0–10 mg/L). Subsequently, the patient was admitted to the hospital for further treatment of urinary tract infection.
Before treatment, cultures of two blood draws and incubated at 37°C in a BACT/ALERT® 3D device (bioMérieux, Marcy l'Etoile, France) immediately, after eight hours they were reported as positive by the incubation device, a gram stain was performed, and the preliminary report of gram-negative bacilli in the culture of the aspirated specimen was made. The direct identification of micro-organisms from blood culture was determined to be Raoultella planticola using MALDI-TOF MS in 10 hours. 4 Finally, antibacterial susceptibility was commenced on VITEK® 2 system and obtained at 16 hours. According to the results of rapid identification, treatment with aztreonam (2 g every 24 hours, intravenously) for three days and the patient's temperature returned to normal and was discharged.
Discussion
Raoultella planticola is a rarely encountered gram-negative bacterium found in the environment. 1 In 2001, Klebsiella planticola was re-classified as Raoultella planticola after a thorough examination of its genetic composition, including sequences for both 16S rRNA and rpoB. 2 The limited presence of comprehensive surveillance studies in the existing literature has contributed to a lack of clarity regarding Raoultella planticola infections, posing challenges in distinguishing them from Klebsiella species. Consequently, there is a potential underestimation of the actual incidence rate. However, recent advancements in diagnostic techniques have led to an increased number of reported cases, suggesting that Raoultella planticola may have been previously overlooked rather than being considered as rare or emerging micro-organisms. 5
In our case, we present a rare case of urinary tract infection caused by Raoultella planticola associated with bacteremia in Suzhou, China. We used MALDI-TOF MS direct identification of micro-organisms from blood culture. Furthermore, we observed the emergence of ampicillin resistance in this bacterial species.
This case demonstrates that quick bacterial identification by MALDI-TOF MS on blood culture material enables rapid administration of relevant treatment to the patient, resulting in decreases of length of hospitalization.6–8 The pathogenic bacterium identified in our patient exhibited resistance to ampicillin. Previous studies have reported the resistance of Raoultella planticola to this antibiotic because of overexpression of class-A β-lactamase.9–11
Conclusions
In conclusion, Raoultella planticola demonstrates significant clinical significance because of its pathogenic nature and capacity for developing antibiotic resistance. The utilization of MALDI-TOF MS for rapid bacterial identification in blood culture material facilitates prompt administration of appropriate treatment to patients, resulting in reduced duration of intensive care unit stays and shorter hospital admissions.
Footnotes
Acknowledgments
We thank the patient's family for sharing this case.
Authors' Contributions
Xu Chen cared for the patient and drafted and revised the manuscript. Xiao Zhang xiao performed standard and specific microbial assays and molecular genetic studies. Shen Hao reviewed the manuscript.
Funding Information
Special Research Project of Infection Management of Suzhou Hospital Association (SZSYYXH-2023-ZD10).
Author Disclosure Statement
Written informed consent was obtained from the patient for publication of this case report. The authors declare that there is no conflict of interest.