What is Raoultella ornithinolytica bacteremia and how is it treated?

Comment by InpharmD Researcher

Raoultella ornithinolytica bacteremia has been scarcely reported in the literature, and data are limited to case reports. A majority of the reported bacteremia cases appear to be attributed to intra-abdominal sources of infection. In general, R. ornithinolytica typically displays in vitro susceptibility to most antibiotics, except penicillin/ampicillin. Patients in the reported cases appear to have responded to broad-spectrum antibiotics, including later generation cephalosporins, piperacillin/tazobactam, aminoglycosides, and carbapenems. As the optimal treatment is not clearly defined, antibiotic selection may be based on susceptibility testing and patient-specific clinical factors.

Background

A 2021 review discussed microbiological and clinical aspects of Raoultella spp., which was first identified in 2001 and had been found to share many ecological, biochemical, clinical, and microbiological features with Klebsiella spp. Similar to Klebsiella spp., Raoultella spp. are also ubiquitous in nature and present in plants, water and soil, and are known to colonize humans and animals. Both genera are facultative anaerobe Gram-negative bacilli, which belong to the family of Enterobacteriaceae, and overlap in several biochemical characteristics, such as production of catalase, the absence of oxidase, the fermentation of glucose, lactose, sorbose and the reduction of nitrates. Nevertheless, certain metabolic characteristics, including indole-test, growth at 10°C, the production of histamine, D-melezitose test, and the metabolism of ornithine, may help differentiate various species. [1]

As described in observational studies and case reports, clinical manifestations associated with R. ornithinolytica varied, including but not limited to urinary tract infections, pneumonia, and bacteremia. Due to the expression of a broad-spectrum β-lactamase, Raoultella spp. are intrinsically resistant to penicillins. Similar to K. pneumoniae and K. oxytoca, wildtype isolates of Raoultella spp. are susceptible to antimicrobials commonly used for the treatment of infections caused by Enterobacterales, such as β-lactams (except penicillins), quinolones, aminoglycosides, tetracyclines, fosfomycin, nitrofurantoin, and polymyxins. As with other Klebsiella species, the concern has been raised for antibiotic resistance to environmental and clinical isolates of Raoultella spp. In one referenced study published in 2020, antimicrobial susceptibility and resistance determinants were evaluated 79 clinical isolates of R. ornithinolytica, and 26 of R. planticola collected from 65 patients from a university hospital in Poland. Overall, susceptibility to all tested antimicrobials was high (≥81.9%), except for amoxicillin/clavulanate (9.5% susceptible; 59.1% intermediate). For β-lactams, the highest susceptibility was observed for imipenem (99%), followed by meropenem (98.1%), and cefepime (88.6%). Regarding non-β-lactams, the highest susceptibility was observed for gentamicin (93.3%) and ciprofloxacin (92.4%). Fourteen isolates (nine R. ornithinolytica and five R. planticola) harbored extended-spectrum β-lactamases. Additionally, the study reported unexpectedly high non-susceptibility to amoxicillin/clavulanate, given that Raoultella β-lactamases are known to be inhibited by clavulanate. Without high-quality clinical data, therapeutic approaches to patients with Raoultella-associated infections should be similar to patients with infections caused by Klebsiella spp., considering individual clinical and pharmacological aspects of the patient, as well as the local epidemiology of antimicrobial resistance. [1], [2]

In a 2014 Korea-based retrospective review, 16 patients were diagnosed with R. ornithinolytica bacteremia over the course of ten years. Universal susceptibility was shown by all isolates to a combination of piperacillin and tazobactam, as well as imipenem. Good susceptibility was shown to cephalosporins, with lower susceptibility shown to cefoxitin overall out of the cephalosporins class, and resistance to multiple cephalosporins, including cefepime, cefotaxime, and ceftazidime, shown in one single case. The most recent six cases were susceptible to meropenem; no cases showed susceptibility to ampicillin. All cases resulted in the patient expiring from septic shock, although it should be noted that fifteen out of the sixteen cases had underlying advanced-stage malignancies. The authors also caution a potential concern for overestimation of R. ornithinolytica strains within this study due to the use of a sensitive identification system and warn of poor prognoses for patients with underlying malignant conditions, regardless of treatment conducted with antibiotics showing susceptibility in vitro. In general, mortality rates were higher in patients with R. ornithinolytica bacteremia (43.8%; 7/16) compared to patients with other types of R. ornithinolytica-infections (8%; 9/112) among evaluated trials. [1], [2], [3]

References:

[1] Appel TM, Quijano-Martínez N, De La Cadena E, Mojica MF, Villegas MV. Microbiological and Clinical Aspects of Raoultella spp. Front Public Health. 2021;9:686789. Published 2021 Aug 2. doi:10.3389/fpubh.2021.686789
[2] Sêkowska A, Bogiel T, Woźniak M, Gospodarek-Komkowska E. Raoultella spp. - reliable identification, susceptibility to antimicrobials and antibiotic resistance mechanisms. J Med Microbiol. 2020;69(2):233-238. doi:10.1099/jmm.0.001150
[3] Chun S, Yun JW, Huh HJ, Lee NY. Clinical characteristics of Raoultella ornithinolytica bacteremia. Infection. 2015;43(1):59-64. doi:10.1007/s15010-014-0696-z
Literature Review

A search of the published medical literature revealed 8 studies investigating the researchable question:

What is Raoultella ornithinolytica bacteremia and how is it treated?

Level of evidence

D - Case reports or unreliable data  Read more→


Please see Tables 1-8 for your response.

 

Bacteremia Caused by Raoultella ornithinolytica in Two Children

Design

Case series

N= 2

Case presentation 1

A 3-year-old girl with IgA nephropathy had persistent proteinuria and was admitted to the hospital, where she was treated with methylprednisolone pulse therapy. Patient had pyrexia without respiratory or gastrointestinal symptoms from the day after the third course of methylprednisolone pulse therapy was completed. Body temperature was 39.6°C, blood pressure 104/60 mmHg, heart rate 120 beats/min, and respiratory rate 30 times. She had no known sick contacts. Physical examination was unremarkable. Laboratory data showed white blood cell count of 8,500/μL and C-reactive protein of 0.67 mg/dL; urinalysis was without abnormalities. Patient was treated with acetaminophen. However, the fever persisted. On the second day, her white blood cell count was 27,600/μL, and C-reactive protein was 18.45 mg/dL. Patient was suspected to have a bloodstream infection, and ceftriaxone was administered. On the third day, a Gram-negative rod, identified as Raoultella ornithinolytica, was isolated; the isolate was susceptible in vitro to ceftriaxone, sulfamethoxazole/trimethoprim, and amoxicillin/clavulanic acid but was resistant to ampicillin, minocycline, ciprofloxacin, and fosfomycin. Patient was treated with intravenous ceftriaxone for two weeks; her fever resolved on the third day, and laboratory data was within normal range by the seventh day without recurrence of fever. 

Case presentation 2

A 7-year-old girl with acute myeloid leukemia was being treated with JPLSG AML05 protocol. Patient had a fever in relation to leukocytopenia after her second course of intensive therapy; body temperature was 39.8°C, blood pressure 86/60 mmHg, heart rate 120 beats/min, and respiratory rate 35 times. Physical examination was unremarkable, and laboratory data on day 1 showed a white blood cell count of < 100/μL and C-reactive protein of 16.31 mg/dL. Meropenem and granulocyte-colony stimulating factor was initiated; the following day, R. ornithinolytica was isolated from her blood. The isolate was susceptible to meropenem, amoxicillin/clavulanic acid, and minocycline but resistant to ampicillin, piperacillin, levofloxacin, and sulfamethoxazole/trimethoprim. Patient was treated with meropenem for 17 days; her pyrexia resolved by day 3, and laboratory data returned to normal ranges with blood culture-negative by day 11. After stopping meropenem, there was no recurrence of fever. 

Study Author Conclusions

Authors encountered 2 immunocompromised children complicated by Raoultella ornithinolytica bacteremia. One had received methylprednisolone pulse therapy for IgA nephropathy, and the other had leukopenia because of chemotherapy for leukemia. Both children had no specific symptoms, and R. ornithinolytica bacteremia was identified by routine blood culture. Both patients were successfully treated with antibiotic treatment.
References:

Yamakawa K, Yamagishi Y, Miyata K, et al. Bacteremia Caused by Raoultella ornithinolytica in Two Children. Pediatr Infect Dis J. 2016;35(4):452-453. doi:10.1097/INF.0000000000001050

 

Raoultella ornithinolytica Bacteremia in Cancer Patients: Report of Three Cases

Design

 Case series

Case presentation 1

 A 92-year-old male with advanced-stage cholangiocarcinoma and hypertension was admitted to the hospital with fever, shaking, chills, and disturbance of consciousness. The patient underwent routine physical and laboratory examinations, finding a white blood cell count of 9,590/μL with 87% neutrophils, a hemoglobin level of 13.6 mg/dL, and a platelet count of 84,000/μL. Blood cultures were obtained and the patient was initiated on treatment with piperacillin/tazobactam 4.5 g Q6 hours per a diagnosis of bacterial cholangitis. On day 2, the blood cultures became positive and a Gram-negative bacillus was isolated and identified as Raoultella ornithinolytica. The isolate exhibited susceptibility to piperacillin, amoxicillin/clavulanate, piperacillin/tazobactam, ceftriaxone, ceftazidime, cefepime, meropenem, gentamicin, levofloxacin, minocycline and trimethoprim/sulfamethoxazole, but resistance to ampicillin. The patient was initiated on a 2-week regimen of piperacillin/tazobactam. Four days after hospitalization, clinical improvement was noted, with labs returning to normal ranges by day 7. 

Case presentation 2

 A 52-year-old woman with advanced-stage pancreatic cancer developing postcholecystectomy was admitted to the hospital with fever, shaking chills, and consciousness disturbance. Laboratory data found a white blood cell count of 13,480/μL with 89% neutrophils, a hemoglobin level of 7.2 mg/dL and a platelet count of 54,000/μL. Blood cultures were obtained, and the patient was initiated on imipenem/cilastatin at a dose of 0.5 g Q6 hours based on a diagnosis of bacterial cholangitis. On day 2, blood cultures were found to be positive for R. ornithinolytica, with susceptibility to piperacillin, amoxicillin/clavulanate, piperacillin/tazobactam, ceftriaxone, ceftazidime, cefepime, meropenem, gentamicin, levofloxacin, minocycline, and trimethoprim/sulfamethoxazole and resistance to ampicillin. Additionally, abdominal computed tomography revealed a potential liver abscess or a biloma with biliary duct dilatation prompting a percutaneous transhepatic abscess drainage. To account for coverage of anaerobes to prevent intraabdominal infection, antimicrobial therapy was changed to cefmetazole at 1 g Q6 hours for an additional 9 days since R. ornithinolytica is resistant to ampicillin. 

Case presentation 3

 A 59-year-old man with gastric cancer presented with fever and chills on postoperative day 5 after distal gastrectomy. Prior to that, the patient's immediate postoperative course was uneventful. Laboratory data revealed a white blood cell count of 8,140/μL with 94% neutrophils, a hemoglobin level of 12.3 mg/dL and a platelet count of 142,000/μL. The patient was started on piperacillin/tazobactam 4.5 g Q6 hours under a diagnosis of bacterial cholangitis due to symptoms and elevation of hepatobiliary enzymes. On postoperative day 6, the blood cultures were found to be positive for R. ornithinolytica. During deescalation, coverage for anaerobes was required, and antimicrobial therapy was changed to cefmetazole 1 g Q6 hours, as R. ornithinolytica was resistant to ampicillin. Antibiotics were administered intravenously for 7 days, eventually changed to oral amoxicillin/clavulanate 500 mg/125 mg three times daily for an additional 7 days. 

Study Author Conclusions

 The authors report three cases of R. ornithinolytica bacteremia associated with biliary tract infections in cancer patients. R. ornithinolytica can be a causative pathogen of biliary tract infection in immunocompromised or postsurgical patients, especially those with underlying cancer.
References:

Hadano Y, Tsukahara M, Ito K, Suzuki J, Kawamura I, Kurai H. Raoultella ornithinolytica bacteremia in cancer patients: report of three cases. Intern Med. 2012;51(22):3193-3195. doi:10.2169/internalmedicine.51.8349

 

Enteric fever-like syndrome caused by Raoultella ornithinolytica (Klebsiella ornithinolytica)

Design

 Case report 

Case presentation

An 82-year-old woman with a history of arterial hypertension and degenerative arthropathy presented at the emergency service suffering from a fever (38°C) and hypotension (84/48 mm Hg). Laboratory results reported elevated white blood cell count at 11,500 cells/mm3, and due to diarrheic episode during hospitalization, antimicrobial therapy with 500 mg ciprofloxacin twice a day orally for 10 days was begun. Blood cultures after 24 hours indicated lactose, indole, and ornithine positive and were identified by the Wider system as R. ornithinolytica. Additional stool cultures showed mucous colonies of a lactose-positive, gram-negative bacillus identified as R. ornithinolytica. Given the high minimum inhibitory concentration (MIC) >16 mg/L for nalidixic acid and ciprofloxacin, treatment was changed to oral doses of amoxicillin-clavulanic acid (875 mg and 125 mg, respectively) every 8 h for 10 additional days. Four days after her admittance, symptoms resolved, the patient was considered cured, and antibacterial treatment was completed at home. Based on the clinical course, R. ornithinolytica bacteremia appeared to be limited and did not recur during therapy, and a course of antibiotic treatment for 10 to 14 days with amoxicillin-clavulanic acid seemed to be curative. 

Study Author Conclusions

In conclusion, Raoultella ornithinolytica is an uncommon cause of enteric fever-like syndrome characterized by fever, headache, and abdominal pain that may be clinically indistinguishable from enteric fever caused by Salmonella enterica serovar Typhi or other salmonellae and should be included in the differential diagnosis of enteric fever. 

Certain epidemiologic data, such as an association with fish consumption, may be of value in diagnosing enteric fever-like syndrome since this syndrome is suspected to be a food-borne disease caused by microbial agents or their toxins.
References:

Morais VP, Daporta MT, Bao AF, Campello MG, Andrés GQ. Enteric fever-like syndrome caused by Raoultella ornithinolytica (Klebsiella ornithinolytica). J Clin Microbiol. 2009;47(3):868-869. doi:10.1128/JCM.01709-08

 

Successful Treatment of a Case of Metallo-Beta-Lactamase-Producing Raoultella ornithinolytica Bacteremia by Antimicrobial Stewardship Team Intervention and Therapeutic Drug Monitoring-Based Amikacin Treatment

Design

Case Report

N= 1

Case presentation

An 80-year-old woman with a past medical history of colorectal cancer, right breast cancer, diabetes mellitus, hypertension, and hyperlipidemia was diagnosed with an intraductal papillary mucinous tumor of the main pancreatic duct type due to dilatation of the main pancreatic duct. The following year, she was diagnosed with adenocarcinoma and admitted to the hospital for perioperative glycemic control and pancreaticoduodenectomy for the intraductal papillary mucinous tumor. 

On the 8th day of hospitalization, she underwent pancreatic cancer resection and developed a fever on the second postoperative day. The patient was given meropenem 0.5 g every 8 hours for suspected cholangitis, followed by a dose increase to 1 g every 8 hours on the third postoperative day. By the fourth postoperative day, her blood culture revealed infection with metallo-beta-lactamase-producing Raoutella ornithinolytica. The patient's infection was resistant to various antibiotics, including piperacillin/tazobactam, fluoroquinolones, and carbapenems. Meropenem was discontinued, and the antimicrobial stewardship team recommended initiating amikacin at 560 mg (12 mg/kg) once every 24 hours based on the patient's condition and therapeutic drug monitoring (TDM) results. Throughout treatment, blood concentrations of amikacin were monitored, and there were no significant adverse effects, such as renal dysfunction or hearing impairment. The patient was successfully treated and eventually discharged without relapse.

Study Author Conclusions

In conclusion, when aminoglycoside antimicrobial agents are administered for MBL-producing R. ornithinolytica bacteremia associated with biliary tract infection, AST intervention and prescription suggestions based on TDM can reduce the occurrence of adverse events and guide the selection of appropriate treatment.
References:

Koishi N, Sasano H, Yoshizawa T, et al. Successful Treatment of a Case of Metallo-Beta-Lactamase-Producing Raoultella ornithinolytica Bacteremia by Antimicrobial Stewardship Team Intervention and Therapeutic Drug Monitoring-Based Amikacin Treatment. Case Rep Infect Dis. 2023;2023:5574769. Published 2023 Apr 7. doi:10.1155/2023/5574769

 

Raoultella ornithinolytica Bacteremia in an Infant with Visceral Heterotaxy

Design

Case Report

N= 1

Case presentation

A male newborn with visceral heterotaxy, functional asplenia, congenital heart block, and double outlet single ventricle was transferred to the hospital and placed on pressors and total parenteral nutrition. He underwent creation of a Blalock-Taussig shunt, pulmonary artery banding, and placement of pacemaker at 3 days of age. On the 12th day, postoperatively enteral alimentation was tried; however, within 24-48 hours patient had signs of necrotizing enterocolitis and septicemia; emergent laparoscopy showed bowel perforation and peritonitis; bowel resection and silo placement were performed, and cultures sent. Empiric antimicrobial treatment was started with cefepime, metronidazole, amikacin, and fluconazole. The blood culture isolate was identified as Raoultella ornithinolytica, while cultures from respiratory sources and follow-up blood cultures showed Klebsiella oxytoca. Physical examination revealed an infant receiving ventilatory and inotropic support while showing marked, red, generalized skin flushing. The R. ornithinolytica isolate was susceptible to aminoglycosides, cefepime, carbapenems, quinolones, and trimethoprim-sulfamethoxazole; the K. oxytoca was susceptible to all beta-lactams except ampicillin and cefazolin. Antimicrobial therapy was changed to amikacin and meropenem, the patient clinically improved, and follow-up cultures were sterile. On day 6 of amikacin and meropenem, the marked, red, generalized skin flushing returned for a week with a concomitant C-reactive protein elevation, after which the patient had no further fevers, flushing, abnormal laboratory studies, or positive cultures.

Study Author Conclusions

In conclusion, this case of R. ornithinolytica bacteremia in an infant is reported to raise awareness of R. ornithinolytica as a human pathogen, a histamine-producing bacteria, and a potential mediator of distinctive cutaneous signs.
References:

Mau N, Ross LA. Raoultella ornithinolytica bacteremia in an infant with visceral heterotaxy. Pediatr Infect Dis J. 2010;29(5):477-478. doi:10.1097/INF.0b013e3181ce9227

 

Catheter-related Blood Stream Infection Caused by Raoultella ornithinolytica

Design

Case report

N= 1

Case presentation

An 8-year-old girl with a history of brain tumor (retinoblastoma), neurogenic bladder, and frequent urinary tract infections presented with fever and, on admission, had a white blood cell count of 12,630/μL, red blood cell count of 3.82 x 106/μL, hemoglobin 11 g/dL and hematocrit 31.9%. The procalcitonin level was 12 mg/L, and C-reactive protein (CRP) was 159 mg/L. Blood culture was collected due to fever, and urine sample was collected for culture. A tunneled catheter was inserted 69 days prior. A culture from the catheter-derived blood was positive after 8 h and 49 min, and after 11 h and 19 min, a positive culture was obtained, both of which grew Raoultella ornithinolytica. The isolates were sensitive to piperacillin, ticarcillin with clavulanic acid, piperacillin with tazobactam, cefuroxime, cefotaxime, ceftazidime, cefepime, imipenem, meropenem, amikacin, tobramycin, netilmicin, ciprofloxacin, and cotrimazole; they were resistant to ampicillin and amoxicillin with clavulanic acid.

The urine culture grew Proteus mirabilis sensitive to piperacillin, ticarcillin with claculanic acid, piperacillin with tazobactam, cefuroxime, cefotaxime, ceftazidime, cefepime, imipenem, meropenem, amikacin, tobramycin, netilmicin, ciprofloxacin, and cotrimazole; no isolates produced extended-spectrum beta-lactamases. The patient was treated with piperacillin with tazobactam (4 x 3.5 g IV) and amikacin (1 x 500 mg IV) for six days. The next day, procalcitonin level was 43 mg/L, CRP was 261 mg/L, and further decreased to 192 mg/L on the third day. By day 4, both blood and urine cultures were negative; on day 5, CRP was 36 mg/L. By day 10, blood and urine samples were obtained and were negative, and the patient recovered. 

Study Author Conclusions

The case report describes catheter-related bacteremia caused by R. ornithinolytica, which was successfully treated with the applied antibiotic therapy (piperacillin with tazobactam and amikacin). As Raoultella spp. infections in humans are rare, and the full implications of Raoultella as a human pathogen remain unknown.
References:

Sękowska A, Dylewska K, Gospodarek E, Bogiel T. Catheter-related blood stream infection caused by Raoultella ornithinolytica. Folia Microbiol (Praha). 2015;60(6):493-495. doi:10.1007/s12223-015-0390-2

 

Clinical Characteristics of Raoultella ornithinolytica Bacteremia: A Case Series and Literature Review

Design

Case series

N= 11

Objective

To report six cases of Raoultella ornithinolytica bacteremia in the study facility with a summary of previously reported 5 cases

Study Groups

Cases at study facility (n= 6)

Cases from previous literature (n= 5)

Inclusion Criteria

 R. ornithinolytica bacteremia, defined as a positive blood culture 

Exclusion Criteria

Not specified 

Methods

A retrospective review of blood culture records was performed at a community hospital in Japan. A signal blood culture system was used prior to 2007, and a BacT/Alert 3D system was used thereafter. Bacterial identification and antibiotic susceptibility testing were performed by the Microscan Walkaway 40 SI system. An additional literature review identified 3 English reports (including 5 patients) that concerned R. ornithinolytica bacteremia. 

Duration

Between 2005 and 2014

Outcome Measures

Treatment regimens, durations, and prognoses; antibiotics susceptibility

Baseline Characteristics/Results

 Case  Sex; Age

Underlying diseases

 Primary focus Antibiotics Duration, days Prognosis 

1

 F; 73 Cerebral infarction Cholangitis  PIPC to CAZ 3 Survived

2

 M; 75 Cholecystolithiasis  Cholangitis  CFPM + AMK

4

 Survived 

3

 F; 92  Cholangitis, pancreatitis,
choledocholithiasis		 Cholangitis  CPZ/SBT to CPFX 

5 

 Survived 

4

 M; 44 Sigmoid colon cancer,
liver metastasis 		 Cholangitis  CPZ/SBT to AMPC/CVA 9  Survived 

5

 M; 65  None  Acute prostatitis  CFPM to LVFX 14  Survived 

6

 F; 77  Cholangiocarcinoma  Cholangitis PIPC/TAZ to CEZ 14  Survived 

7

 F; 82  Degenerative arthropathy  Enterocolitis   CPFX to AMPC/CVA 20  Survived 

8

 M; 0  Visceral heterotaxy, asplenia,
congenital cardiac anomaly 		 Cholangitis  CFPM, MNZ, AMK to MEPM, AMK  7  Survived 

9

 M; 92  Cholangiocarcinoma  Cholangitis  PIPC/TAZ  14  Survived 

10

 F; 52  Pancreatic cancer  Cholangitis  IMP/CS to CMZ  15  Survived 

11

 M; 59  Gastric cancer  Cholangitis  PIPC/TAZ to CMZ to AMPC/CVA 14  Survived 

The isolates were resistant to ampicillin but showed susceptibility to piperacillin (70%, 7/10 cases), cefotaxime (100%, 7/7 cases), and levofloxacin (100%, 10/10 cases).

The pathogens were susceptible to both third-generation cephalosporin and fluoroquinolone, and all 11 patients were treated effectively with antibiotic therapy.

Cases 1-6 represented institutional reports, while cases 7-11 were from literature review. 

AMK: amikacin; AMPC/CVA: amoxicillin/clavulanate; CAZ: ceftazidime; CEZ: cefazolin; CFPM: cefepime; CMZ: cefmetazole; CPFX: ciprofloxacin; CPZ/SBT: cefoperazone/sulbactam; IMP/CS: imipenem/cilastatin; LVFX: levofloxacin; MEPM: meropenem; MNZ: metronidazole; PIPC: piperacillin; PIPC/TAZ: peperacillin/tazobactam.

Study Author Conclusions

In conclusion, authors have summarized the clinical characteristics of R. ornithinolytica bacteremia in this report. A major focus of the bacteremia was biliary infection. It appears that elderly patients with a history of any biliary interventions, biliary tract diseases, or malignancy are at elevated risk for R. ornithinolytica bacteremia. The patients had an excellent prognosis with antibiotic therapy, but further study with additional patients and more reliable identification methods would be required to confirm our findings

InpharmD Researcher Critique

As the trial is conducted in Japan, treatment options and antibiotic resistance patterns may not be readily applicable to the US population. Generalizability of case series remains limited to a broader patient population with R.ornithinolytica bacteremia. 



References:

Haruki Y, Hagiya H, Sakuma A, Murase T, Sugiyama T, Kondo S. Clinical characteristics of Raoultella ornithinolytica bacteremia: a case series and literature review. J Infect Chemother. 2014;20(9):589-591. doi:10.1016/j.jiac.2014.05.005

 

Clinical Characteristics of Raoultella ornithinolytica Bacteremia and Antimicrobial Susceptibility of Raoultella ornithinolytica

Design

Case series

N= 62

Objective

To perform a retrospective analysis of cases of Raoultella ornithinolytica infection at the author's hospital

Inclusion Criteria

Patients with specimens found to be positive for R. ornithinolytica 

Exclusion Criteria

N/A

Methods

A retrospective review of specimen records was performed at a hospital in Japan. Clinical course of these patients was investigated via data from electronic medical records. Specimens included sputum, urine, stool, blood, bile, and others. 

Duration

September 2019 to July 2021

Outcome Measures

Clinical course and prognosis

Baseline Characteristics

  

All patients

(N= 62)

 

      

Age, years

 80.6        

Specimen

Sputum

Urine

Blood

Stool

Bile

Other

 

24

19

6

3

4

6

        

Results

Case

Age (years)/sex

Primary disease

Treatment

Outcome

Culture result

1

 77/male Acute complicated pyelonephritis Ceftriaxone, clean intermittent catheterization Alive R. ornithinolytica was also detected in urine culture.

2

85/male 

 Common bile duct stones, cholangitis  Cefoperazone/sulbactam, drainage  Alive Bile cultures were not submitted

3

 80/male Acute cholangitis, liver abscess Meropenem Improved by died due to cancer R. ornithinolytica was also detected in bile culture.

4

 85/male Common bile duct stones, cholangitis Meropenem, then cefoperazone/sulbactam and drainage

Alive

 Bile culture was negative.

5

 79/male Acute cholangitis Cefoperazone/sulbactam, drainage Improved but died due to cancer Bile cultures were not submitted.

6

 78/male Acute complicated pyelonephritis Tazobactam/piperacillin then levofloxacin and clean intermittent catheterization Alive R. ornithinolytica was also detected in urine culture.

*Above summary is only for blood culture-positive cases.

Overall, R. ornithinolytica showed good susceptibility to most antimicrobial agents but poor susceptibility to ampicillin, piperacillin, and fosfomycin.

Adverse Events

 N/A

Study Author Conclusions

 R. ornithinolytica has recently been reported to be pathogenic in patients with severe and without obvious underlying diseases. In this study, all patients positive with R. ornithinolytica detected in the urine or sputum had a predisposition to be easily infected. Additionally, some of these patients with R. ornithinolytica detected in sputum died of pneumonia. Thus, we believe that great caution should be exercised in treating these patients. Although R. ornithinolytica is susceptible to antimicrobial agents other than penicillin, the emergence of resistant strains has been reported. In addition, it is sometimes difficult to distinguish R. ornithinolytica from Klebisella oxytoca, Enterobacter aerogenes and other Raoultella spp., and thus further accumulation of cases for research is desirable.

InpharmD Researcher Critique

The case series provides superficial insight into clinical outcomes of a select number of patients. The included sample size was small; furthermore, the available data was not sufficient to decipher whether R. ornithinolytica is a carrier or a causative bacterium.



References:

Etani T, Kondo S, Yanase T, et al. Clinical characteristics of Raoultella ornithinolytica bacteremia and antimicrobial susceptibility of Raoultellaornithinolytica. J Infect Chemother. 2023;29(5):554-557. doi:10.1016/j.jiac.2023.01.023