Raoultella ornithinolytica Urinary Tract Infection in a Patient With Triple-Negative Breast Cancer.

Due to the challenges associated with accurately identifying Raoultella ornithinolytica as the causative agent in urinary tract infections (UTIs), coupled with limited guidance on treatment protocols, reports of similar cases still need to be made publicly available because of their increasing emergence. In this article, we present the first documented case of a UTI caused by Raoultella ornithinolytica in a patient with triple-negative breast cancer undergoing neoadjuvant chemotherapy. This case report highlights Raoultella ornithinolytica as an uncommon yet significant pathogen, particularly in immunocompromised patients. Given the bacterium's antibiotic resistance patterns, it emphasizes the importance of prompt, accurate identification methods and tailored treatment strategies, especially in vulnerable populations undergoing chemotherapy.

Acute Encephalopathy in a Patient with Raoultella Ornithinolytica Infection: A Challenging Presentation.

Raoultella ornithinolytica is a rare, gram-negative environmental enterobacterium. Although infections in humans caused by R. ornithinolytica are uncommon, there are increasing reports implicating it in urinary tract infections, hepatobiliary infections, and bacteremia, designating it as an emerging pathogen. Its habitat is primarily in aquatic environments and soil, with seafood frequently identified as a potential source of infection. While these infections have predominantly been described in immunocompromised patients previously, our case suggests that advanced age may be a significant risk factor. We describe a case of a 73-year-old man presenting with encephalopathy who then was found to have R. ornithinolytica bacteremia from a genitourinary source. Following antibiotic treatment, the infection resolved and the neurologic symptoms improved. To the best of our knowledge, this is the first documented case in the medical literature of R. ornithinolytica featuring a primary neurologic presentation.

Abdominal abscess caused by Raoultella ornithinolytica secondary to postoperative gastric fistula: case report and review of literature.

BACKGROUND: In recent years, Raoultella ornithinolytica (R. ornithinolytica) have attracted clinical attention as a new type of pathogen. A wide range of infections with these germs is reported, and commonly found in urinary tract infections, respiratory infections, and bacteremia. CASE PRESENTATION: We report the case of an elderly woman with liver abscess, choledocholithiasis and cholangitis, who developed gastric fistula and abdominal abscess after underwent choledocholithotomy, and R. ornithinolytica were isolated from the abdominal drainage fluid. The patient was treated with meropenem and levofloxacin and had a good outcome. CONCLUSIONS: To the best of our knowledge, case of isolating R. ornithinolytica from a patient with non-viscerally abdominal abscess was extremely rare. We share a case of a woman with non-viscerally abdominal abscess secondary to postoperative gastric fistula, R. ornithinolytica was isolated from the patient's pus, and the pathogenic bacteria may originate from the gastrointestinal tract. Based on this case, We should be cautious that invasive treatment may greatly increase the probability of infection with this pathogenic bacterium.

A rare case of multi-drug resistant Raoultella ornithinolytica-induced sepsis in a healthy young man in Uganda.

Key Clinical Message: Antimicrobial resistance (AMR) is a public health challenge. It causes unresponsiveness to treatment with antimicrobials, leads to sepsis, septic shock, and increased hospital mortality. This is compounded by new multidrug resistant organisms. We present and discuss a case of sepsis caused by a rare multi-drug resistant bacterium Raoultella ornithinolytica. Abstract: Antimicrobial resistance is a major public health concern worldwide, associated with nearly 5 million deaths. The highest mortality attributed to AMR is seen in sub-Saharan Africa. Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae, Streptococcus pneumoniae, Acinetobacter baumannii, and Pseudomonas aeruginosa contribute to most deaths attributed to AMR globally. However, other uncommon microorganisms have been implicated. Few cases of resistant, extended-spectrum beta-lactamase (ESBL) producing Raoultella ornithinolytica have been reported to cause sepsis worldwide. To our knowledge, no case of R. ornithinolytica-induced sepsis has been reported in our settings. We report a case of sepsis due to R. ornithinolytica in an injured young adult. We received a 36-year-old man, a professional banker involved in a road traffic accident 2 h before admission. He sustained a deep degloving wound on the right ankle with exposure of the lateral malleolus and presented with severe pain, and bleeding at the injury site. x-Rays confirmed a comminuted intra-articular distal tibia and fibular fracture. Surgical debridement and external fixation were aseptically done on the same day. Below knee amputation was done on the 7th day post-admission due to extensively injured and infected limb with sepsis. Local pus culture isolated ESBL-positive R. ornithinolytica susceptible only to meropenem, ciprofloxacin, and amikacin. Introducing these antibiotics on the 11th post-admission day averted sepsis and enhanced patient recovery. With the threat of AMR, newly emerging highly resistant microbes should be expected and suspected. Early recognition of sepsis and its focus and precise intervention with antimicrobials guided by specimen culture and susceptibility profile is highly recommended and should be standard practice. It highly reduces morbidity and mortality due to sepsis.

Evaluation of the in vitro effects of concentrations of antibiotics on three Enterobacteriaceae isolates.

Due to the misuse and overuse of antibiotics, bacteria are now exposed to sub-minimum inhibitory concentrations (sub-MICs) of antibiotics in various environments. In recent years, exposure of bacteria to sub-MICs of antibiotics has led to the widespread emergence of antibiotic-resistant bacteria. In this study, three bacterial species from the Enterobacteriaceae family (Raoultella ornithinolytica, Pantoea agglomerans and Klebsiella quasivariicola) were isolated from water. The antibiotic susceptibility of these bacteria to 16 antibiotics was then investigated. The effects of sub-MICs of four selected antibiotics (kanamycin, chloramphenicol, meropenem, and ciprofloxacin) on the growth, biofilm formation, surface polysaccharide production, siderophore production, morphology, and expression of the translational/transcriptional regulatory transformer gene rfaH of these bacteria were analysed. The MICs of kanamycin, chloramphenicol, meropenem, and ciprofloxacin were determined to be 1, 2, 0.03 and 0.03 µg/mL for R. ornithinolytica; 0.6, 6, 0.03 and 0.05 µg/mL for P. agglomerans; and 2, 5, 0.04 and 0.2 µg/mL for K. quasivariicola. The growth kinetics and biofilm formation ability decreased for all three isolates at sub-MICs. The surface polysaccharides of R. ornithinolytica and P. agglomerans increased at sub-MICs. There was no significant change in the siderophore activities of the bacterial isolates, with the exception of MIC/2 meropenem in R. ornithinolytica and MIC/2 kanamycin in K. quasivariicola. It was observed that the sub-MICs of meropenem and ciprofloxacin caused significant changes in bacterial morphology. In addition, the expression of rfaH in R. ornithinolytica and K. quasivariicola increased with the sub-MICs of the selected antibiotics.

Molecular characteristics of carbapenem-resistant Raoultella ornithinolytica.

Aim of this study was to explore molecular characteristics and resistance mechanisms of carbapenem-resistant Raoultella ornithinolytica (CR-ROR) isolated from patients in a hospital in China. Three CR-ROR strains were collected and bacterial identification was done by Matrix-Assisted Laser Desorption/Ionization Time of Flight Mass Spectrometry (MALDI-TOF-MS) Vitek-MS and by digital DDH analysis. VITEK 2 compact system and Kirby-Bauer (K-B) disk diffusion were used for antimicrobial susceptibility testing. Whole genome sequencing was carried out using the Illumina platform NovaSeq sequencer. Abricate software was used for the prediction of antibiotic resistance genes of three CR-ROR strains. The phylogenetic tree was constructed through genome SNPs to investigate the genetic relationship of three CR-ROR strains. Three CR-ROR (WF1357, WF2441, and WF3367) strains were collected in this study. Two strains were isolated from neurosurgery (WF1357 and WF2441), and one was isolated from pulmonology department (WF3367). All strains harboured multiple antibiotic resistance genes. Two strains (WF1357, WF2441) carried the blaNDM-1 gene, one of the strains (WF3367) carried the blaKPC-2 gene. Three CR-RORs were resistant to different antimicrobial agents including carbapenems. The three CR-ROR strains collected in this study and 51 CR-ROR strain genomes downloaded from NCBI, were divided into six evolutionary groups (A-F). In this study, three CR-ROR strains were found to have a higher level of resistance to antibacterial agents and carried multiple antibiotic resistance genes. The CR-ROR strains carrying multiple antibacterial resistant genes require the stringent monitoring to avoid the spread of multidrug-resistant bacterial strains.

Emergence of NDM-1-producing Raoultella ornithinolytica from reservoir water in Northeast Thailand.

Background and Aim: Antibiotic resistance is a major global health threat. The increasing prevalence of drug-resistant bacteria poses a serious challenge to the effective treatment of infections in both humans and animals. Water is a major source of human and animal exposure to bacteria, and the presence of drug-resistant bacteria in water could present a severe threat to public health and animal production. This study investigated the presence of drug-resistant bacteria in Lam Pao Dam (LPD) water in Kalasin, Thailand. Materials and Methods: Ampicillin-resistant strains were obtained from LPD water and identified using 16s rDNA sequencing. Antibiotic resistance genes were detected by polymerase chain reaction using specific primers. The presence of antibiotic-resistant bacteria was evaluated using 16s amplicon analysis. The minimum inhibitory concentration (MIC) of Raoultella ornithinolytica strains against antibiotics was determined. Results: A total of 12 R. ornithinolytica, 4 Bacillus cereus, and 4 Enterococcus faecalis isolates were resistant to ampicillin. Almost all R. ornithinolytica strains harbored blaSHV and blaOXA genes, and two strains also harbored the blaNDM-1 gene. All four E. faecalis strains harbored the blaIMP gene. The most abundant species in the LPD sample was Exiguobacterium indicum, followed by E. faecalis and R. ornithinolytica. The MICs of 10 R. ornithinolytica strains against five antibiotics revealed that all strains were resistant to ampicillin but susceptible to meropenem, doripenem, ertapenem, and imipenem. Conclusion: These findings suggest a high prevalence of drug-resistant bacteria in LPD water. This is a cause for concern, as it could spread antibiotic-resistant infections in the community.

Raoultella Ornithinolytica in a Healthy, Young Person: Rapidly Progressive Sinusitis with Orbital and Intracranial Involvement.

Raoultella ornithinolytica is an encapsulated, Gram-negative, nonmotile, rod belonging to the Enterobacteriaceae family. Infections involving the gastrointestinal tract and the hepatopancreatobiliary system are most frequently reported, especially in immunocompromised patients. The authors present an unusual case of acute complicated sinusitis with orbital and intracranial involvement caused by R. ornithinolytica. The infection was rapidly progressive, even though the patient was a healthy, young person without any co-morbidities. The patient's condition improved after antibiotic treatment and multiple ophthalmic and sinus surgeries. LEARNING POINTS: Raoultella ornithinolytica can cause rapidly progressive infections, even in immunocompetent young individuals.Raoultella ornithinolytica identified in sinusitis can be a true pathogen rather than an innocent bystander.

Effects of Luteolin-7-O-Glucoside on Intestinal Microbiota Dysbiosis and Drug Resistance Transmission Caused by Raoultella ornithinolytica B1645-1: Modulating the Composition of Intestinal Microbiota and Promoting the Transfer of blaNDM-1 Gene from Genus Enterococcus to Lactobacillus in Mice.

Raoultella ornithinolytica is an Enterobacteriaceae bacterium that can infect both humans and animals, while luteolin-7-O-glucoside (IOG) is a flavonoid that has broad effects on the intestinal microbiota of healthy animals. However, current studies lack sufficient data on intestinal microbiota dysbiosis and drug resistance transmission caused by R. ornithinolytica and the possible role of IOG. In this study, BALB/c mice were infected with R. ornithinolytica carrying blaNDM-1 gene and treated with IOG (3 mg/kg·d and 6 mg/kg·d) to analyze the diversity of intestinal microbiota and the transfer of blaNDM-1 between bacteria. The findings indicated that R. ornithinolytica B1645-1 exhibited a significant ability to enhance the Firmicutes/Bacteroidota ratio and increase the relative abundance of Lactobacillus and Bacillus after 48 h, where as 6 mg/kg·d IOG had an opposite effect. Moreover, R. ornithinolytica B1645-1 facilitated the emergence of drug-resistant bacteria and promoted blaNDM-1 gene transfer in Enterococcus, Escherichia, Klebsiella, Acinetobacter, Bacillus, Brevibacterium, and Lactobacillus. Enterococcus was the predominant genus at 48 h. Surprisingly, 6 mg/kg·d IOG significantly inhibited the production of drug-resistant bacteria and promoted blaNDM-1 gene transfer from Enterococcus to Lactobacillus at 144 h. However, the role of Lactobacillus as a recipient for drug-resistant genes should be of more concern.

Whole genome sequencing data of Raoultella ornithinolytica PX02 isolated from San Jacinto river sediment in Baytown, Texas.

Raoultella ornithinolytica PX02 is a Gram-negative, encapsulated bacterium, part of the Enterobacteriaceae family, emerging as a notable human pathogen. Here, we present the whole genome sequence of R. ornithinolytica PX02 isolated from San Jacinto River sediment near a Burnet Shores community in Baytown, Texas. This microorganism harbors a large 200,000 bp incF plasmid and can potentially be a significant antibiotic reservoir. The PX02 genome consists of 5,970,914 base pairs encoding approximately 5,661 functional proteins. Strain PX02 (chromosomal and plasmid) was compiled at the scaffold level and can be accessed through the National Center for Biotechnology Information database under accession NZ_NJBC00000000.1.

Emergence of Raoultella ornithinolytica in human infections from different hospitals in Ecuador with OXA-48-producing resistance.

Purpose: The purpose of this study was to highlight the clinical and molecular features of 13 Raoultella ornithinolytica strains isolated from clinical environments in Ecuador, and to perform comparative genomics with previously published genomes of Raoultella spp. As Raoultella is primarily found in environmental, clinical settings, we focused our work on identifying mechanisms of resistance that can provide this bacterium an advantage to establish and persist in hospital environments. Methods: We analyzed 13 strains of Raoultella ornithinolytica isolated from patients with healthcare associated infections (HAI) in three hospitals in Quito and one in Santo Domingo de Los Tsáchilas, Ecuador, between November 2017 and April 2018. These isolates were subjected to phenotypic antimicrobial susceptibility testing, end-point polymerase chain reaction (PCR) to detect the presence of carbapenemases and whole-genome sequencing. Results: Polymerase chain reaction revealed that seven isolates were positive isolates for blaOXA-48 and one for blaKPC-2 gene. Of the seven strains that presented the blaOXA-48 gene, six harbored it on an IncFII plasmid, one was inserted into the bacterial chromosome. The blaKPC gene was detected in an IncM2/IncR plasmid. From the bioinformatics analysis, nine genomes had the gene blaOXA-48, originating from Ecuador. Moreover, all R. ornithinolytica strains contained the ORN-1 gene, which confers resistance for ß-lactams, such as penicillins and cephalosporins. Comparative genome analysis of the strains showed that the pangenome of R. ornithinolytica is considered an open pangenome, with 27.77% of core genes, which could be explained by the fact that the antibiotic resistance genes in the ancestral reconstruction are relatively new, suggesting that this genome is constantly incorporating new genes. Conclusion: These results reveal the genome plasticity of R. ornithinolytica, particularly in acquiring antibiotic-resistance genes. The genomic surveillance and infectious control of these uncommon species are important since they may contribute to the burden of antimicrobial resistance and human health.

Identification of TMexCD-TOprJ-producing carbapenem-resistant Gram-negative bacteria from hospital sewage.

Carbapenems and tigecycline are crucial antimicrobials for the treatment of gram-negative bacteria infections. Recently, a novel resistance-nodulation-division (RND) efflux pump gene cluster, tmexCD-toprJ, which confers resistance to tigecycline, has been discovered in animals and clinical isolates. It was reported that hospital sewage could act as a reservoir for gram-negative bacteria with high antimicrobial resistance genes. In this study, we analyzed 84 isolates of carbapenem-resistant gram-negative bacteria (CR-GNB) from hospital sewage, and identified five isolates of TMexCD-ToprJ-producing CR-GNB, including one Raoultella ornithinolytica isolate and four Pseudomonas spp. isolates. All these five isolates carried at least one carbapenem resistance gene and were resistant to multiple antibiotics. Multiple tmexCD-toprJ clusters were detected, including tmexC2D2-toprJ2, tmexC3D3-toprJ3, tmexC3.2D3.3-toprJ1b and tmexC3.2D3-toprJ1b. Among these clusters, the genetic construct of tmexC3.2D3-toprJ1b showed 2-fold higher minimum inhibitory concentration (MIC) of tigecycline than other three variants. In addition, it was found that the tmexCD-toprJ gene cluster was originated from Pseudomonas spp. and mainly located on Tn6855 variants inserted in the same umuC-like genes on chromosomes and plasmids. This unit co-localized with blaIMP or blaVIM on IncHI5-, IncpJBCL41- and IncpSTY-type plasmids in the five isolates of TMCR-GNB. The IncHI5- and IncpSTY-type plasmids had the ability to conjugal transfer to E. coli J53 and P. aeruginosa PAO1, highlighting the potential risk of transfer of tmexCD-toprJ from Pseudomonas spp. to Enterobacterales. Importantly, genomic analysis showed that similar tmexCD-toprJ-harboring IncHI5 plasmids were also detected in human samples, suggesting transmission between environmental and human sectors. The emergence of TMCR-GNB from hospital sewage underscores the need for ongoing surveillance of antimicrobial resistance genes, particularly the novel resistance genes such as the tmexCD-toprJ gene clusters in the wastewater environment.

Raoultella ornithinolytica as a Potential Candidate for Bioremediation of Heavy Metal from Contaminated Environments.

Disposal of waste containing heavy metals into the environment is a major threat to human health and can result in toxic or chronic poisoning in aquatic life. In the current study, metal-resistant Raoultella ornithinolytica was isolated from metal-contaminated samples collected from the Tanjaro River, located southwest of Sulaymaniyah, Iraq. R. ornithinolytica was identified by partial amplification of 16S rRNA. The uptake potency of heavy metals was assessed using inductively coupled plasma-optical emission spectroscopy (ICP-OES) and indicated that R. ornithinolytica removed 67, 89, 63.4, 55.6, 56.5, 65, and 61.9% of Cd, Pb, Cr, Ni, Zn, Co, and Fe, respectively. These removal rates were influenced by temperature, pH, and contact time; at 35°C and pH 5 with a change in the incubation time, the reduction rate improved from 89 to 95% for Pb, from 36.4 to 45% for Cu, and from 55.6 to 64% for Ni. Gene analysis indicated that R. ornithinolytica contained pbrT, chrB, nccA, iroN, and czcA genes, but the pcoD gene was absent. Energy-dispersive X-ray spectroscopy (EDS) images showed evidence of metal ion binding on the cell wall surface with different rates of binding. Transmission electron microscopy (TEM) detected different mechanisms for metal particle localization; cell surface adsorption was the main mechanism for Pb, Zn, and Co uptake, while Cd, Ni, and Fe were accumulated inside the cell. The current study describes, for the first time, the isolation of R. ornithinolytica from metal-contaminated water, which can be used as an eco-friendly biological expedient for the remediation and detoxification of metals from contaminated environments.

Clinical characteristics of Raoultella ornithinolytica bacteremia and antimicrobial susceptibility of Raoultellaornithinolytica.

Raoultella ornithinolytica (R. ornithinolytica) is a gram-negative rod that was considered related to Klebsiella oxytoca and was classified as R. ornithinolytica in 2001. R. ornithinolytica is known as a histamine-producing bacterium that causes mackerel poisoning. Although only few clinical cases of R. ornithinolytica infection in humans have been reported, the number of diagnosed cases is expected to increase owing to the advancements in identification methods. In the present study, we performed a retrospective analysis of cases of R. ornithinolytica infection detected at our hospital. From September 2019 to July 2021, 62 specimens positive for R. ornithinolytica were obtained after removing duplicates. The clinical courses of these cases were investigated retrospectively based on electronic medical records. Of the 62 specimens, 24 were sputum, 19 were urine, three were stool, six were blood, four were bile, and six were other specimens. All the six blood culture specimens in which R. ornithinolytica was detected were from male patients, and the causative diseases were cholangitis in four cases and complicated pyelonephritis in two cases. Of these, two patients with cholangitis succumbed to death due to the worsening of underlying cancer. Identification of R. ornithinolytica is reportedly difficult, and some instruments may misidentify it as Klebsiella oxytoca. The prognosis of R. ornithinolytica infection has been reported to be good when susceptible drugs are used. However, high mortality rates were also reported despite the use of these drugs, suggesting the need for further investigation of clinical features of R. ornithinolytica infection.

Isolation and identification of the molybdenum-resistant strain Raoultella ornithinolytica A1 and its effect on MoO42- in the environment.

The mining and leakage of molybdenum (Mo) can cause environmental contamination which has not been realized until recently. Bacteria that can mitigate Mo-contamination was enriched and isolated. The low temperature and different pH conditions were considered to analysis its feasibility in Northern China which suffers from a long time of low temperatures every year. The result showed that the removal rate of MoO42- by Raoultella ornithinolytica A1 reached 30.46% at 25 °C and pH 7.0 in Luria-Bertani medium (LB). Meanwhile, A1 also showed some efficiency in the reduction of MoO42- in low phosphate molybdate medium (LPM), which reached optimum at the MoO42- concentration of 10 mM. The results of FTIR indicated that the cell wall performed an essential role in the MoO42- removal process, which was illustrated by the distribution of Mo in A1 (Mo bound to cell wall accounted for 92.29% of the total MoO42- removed). In addition, low temperature (10 °C) effect the removal rate of MoO42- by - 8.38 to 11.66%, indicating the potential for the in-situ microbial remediation of Mo-contaminated environments in low temperature areas.

Characterization of Immobilized Magnetic Fe3O4 Nanoparticles on Raoultella Ornithinolytica sp. and Its Application for Azo Dye Removal.

A high-performance immobilized bacterial strain coated with magnetic iron oxide nanoparticles was used for Basic Blue 41 azo dye (BB 41 dye) decolorization. To create the coated bacterial strain, Raoultella Ornithinolytica sp. was isolated and identified under the accession number KT213695, then coated with manufactured magnetic iron oxide nanoparticles. SEM and SEM-EDX were used to characterize the coated bacteria and validate its morphological structure formation. The coated Raoultella Ornithinolytica sp. A1 (coated A1) generated a 95.20% decolorization for BB 41 dye at 1600 ppm starting concentration with an optimal dose of coated A1 5 mL/L, pH 8, under static conditions for 24 h at 37 °C. Continuous batch cycles were used, with BB 41 dye (1600 ppm) added every 24 h four times, to achieve a high decolorization efficiency of 80.14%. Furthermore, the metabolites of BB 41 dye biodegradation were investigated by gas chromatographic-mass spectrum analysis (GC-MS) and showed a less toxic effect on the bioindicator Artemia salina. Additionally, 5 mL/L of coated A1 demonstrated the highest decolorization rate (47.2%) when applied to a real wastewater sample after 96 h with a consequent reduction in COD from 592 to 494 ppm.

Case Study: Soft tissue infection with Raoultella ornithinolytica.

Raoultella ornithinolytica is a rare encapsulated Gram-negative aerobic and facultative anaerobic rod belonging to the Enterobacteriaceae family. It tends to inhabit water and soil environments and can be found on insects, fish, ticks, and termites, but can also found in the hospital environment.1 , 2 R ornithinolytica has been documented in respiratory, urinary, gastrointestinal, and biliary tract infections as well as bacteraemia and systemic infections but has rarely been documented in soft tissue infections.2 This case study describes a recurrent paronychia infection secondary to R ornithinolytica in a young woman not responding to antibiotics and successfully treated with surgical management.

Sepsis From Multisystem Infection With Multidrug-Resistant Raoultella ornithinolytica.

Raoultella (R.) ornithinolytica is a gram-negative, encapsulated aerobe or facultative anaerobe belonging to the family Enterobacteriaceae. It is distinguished from other members in the family with a negative indole test, growth at 10oC, production of histamine, a negative D-melezitose test, and metabolism of ornithine. R. ornithinolytica is a versatile organism found in different habitats, including soil, water, and plants, as well as colonizing the human gastrointestinal tract and throat. It was considered to cause opportunistic infection in humans but is increasingly being implicated in infections in immunocompetent individuals. Raoultella ornithinolytica causes infection in different clinical settings. Sepsis from Raoultella ornithinolytica is increasing among humans, and it is considered an emerging infectious agent in both immunocompromised and immunocompetent people. There is an increasing level of antibiotic resistance among isolates with reports of multidrug resistance. We report the case of a 95-year-old man with multidrug-resistant R. ornithinolytica multisystem infection and review the literature.