DOI: The Greek E-Journal of Perioperative Medicine 2022;21(a): 51-56

Authors: Myrou A.1a*, Aslanidis Th.2b, Savopoulos Ch.3a, Didangelos T.4a

1MD, MSc, PhD, Internal Medicine – Diabetes and Hypertension – Critical Care.
ORCID: 0000-0002-2629-1841

2MD, PhD, Anesthesiology – Critical Care -Prehospital emergency medicine.
ORCID: 0000-0002-8325-8861

3Prof, Internal Medicine,
ORCID ID: 0000-0002-7970-2464

4Asoc.Prof., Internal Medicine-Diabetes,
ORCID 0000-0002-0236-8760

aFirst Propaedeutict Internal Medicine Department, AHEPA University Hospital, Thessaloniki, Greece
bIntensive Care Unit, “Agios Pavlos” General Hospital, Thessaloniki, Greece

*Corresponding Author:Doridos str 4, PC 54633, Thessaloniki, Greece. E-mail: Tel.: +306972477166.



Raoultella planticola is a Gram-negative, oxidase-negative, aerobic that belongs to Enterobacteriaceae family and has a lot of similarities with Klebsiella spp. Though initially rare mentioned as an opportunistic infection, more and more reports are published. In the present article we present a case of an R. planticolla upper respiratory infection and we review the relevant literature.



Raoultella planticola is a Gram-negative, oxidase-negative, aerobic, nonmotile, encapsulated rod commonly found in water, soil, and aquatic environments and belongs to the genus Raoultella, the family Enterobacteriaceae. Due to similarities to Klebsiella spp, Rooultella spp. was established in 2001. The species now includes Raoultella planticola, Raoultella ornithinolytica, Raoultella terrigena, Raoultella electrica1. Though initially considered as a rare cause of infections in humans, today it is mentioned as an emerging pathogen. In the present article we present a case of an R. planticolla upper respiratory infection and we review the relevant literature.



A 58-year-old male patient was referred to our hospital by his doctor for sweatings, fever (upto 38.4oC), fatigue, appetite and weight loss and intermittent constrictive neck pain. The symptomatology was already ongoing for a month and the out-of-hospital investigation was inconclusive. Recent history excluded SARS-CoV2 infection, any animals contacts, travelling abroad, or any chemicals exposure. Previous history included arterial hypertension under perindopril arginine / amlodipine 5+5mg q.d. p.os, idiopathic thrombocythemia under acetylsalicylic acid 100 mg q.d. p.os,  hyperuricemia under allopurinol 300mg p.d. p.os and nebivolol 2.5mg q.d. p.os, ulcerative colitis for the last 12 years , yet free-of symptoms for the last 5 year, smoking 30 packs/year  (stopped in 2005), alcohol use (5 drinks/ week till 2001), p.os; no allergies,  and amputation of left lower limb after post traumatic osteomyelitis at the age of 20.

On admission clinical examination, no major abnormities were noted (BP- 150/80 mmHg, HR-86 bpm, SpO2 – 96% on room air with no dyspnoea or tachypnoea, temp- 36.9oC).  Blood and uring cultures for microbiological screening turn out negative. The patient remained in the hospital for 8 days with a steadily improving clinical status and mild tempeture (up to 37.3oC). During his hospitalisation, due to abnormal laboratory examination (Table 1), extensive imagining and labooratory investigation was carried out; yet, with norelated findings: Cyst in the base of the tongue, overriding arytenoids of small clininical importance, left eye cataract, nasal diaphragm scoliosis, paranasal sinuses mucosal thickening, mild carotid disease,  several (3) small benign thyroid nodules, non-specific <5mm nodules in upper lung lobes, small (8 mm) liver hemangioma (section VII), cholelithiasis, Splenomegalia 13.2 cm , Splenule 2 cm and signs of previous inflammation of greater omentum.

Table 1. Selected lab values course on the first 4 days of investigation (only abnormal values are displayed).

ESR CRP γ-GT IL-6 Ferritin suPAR WBC Neu Leu PCT
mg/dl U/l pg/ml ng/ml ng/ml K/μL % % ng/ml
165 17.2 100 35.4 874.8 4.6 15.35 85 8.4 0.64
β2-mgl AAT Fib D-dim CA 19-9 Alb*  α1* α2* γ* APCA
mg/dl mg/dl mg/dl ng/ml U/l % % % %  
1.4 27 992 618 29.2 42.4 9.5 23.2 11,9 positive

ESR- erythrocytes sedimentation rate, CRP-creatine reactive protein, γGT- gamma glutaril transpherase, IL-interleukin, suPAR- soluble urokinase plasminogen activator receptor, WBC- white blood cells, Neu- neurophils, leu- leucocytes, PCT-procalcitonin, mgl- macroglobulin, AAT- a1 antithrypsin, Fib-fibrinogen, D-dim – D-dimers, CA- cancer antigen, Alb- albumin, * Serum protein electrophoresis resultas, APCA-anti-parital cell antibodies.

Thus, the patient was discharged from hospital in improved clinical status. However, 4 days later, he again returned to the hospital mentioning again fever (up to 38oC) with no other complaints, yet with abnormal lab results. Further investigation with repeated blood and uringe cultures, bone marrow, gastric and colon biospies and positron emitting tomography imaging; yet sputum cultures following antibiogram identified a multisensitive Raoultella planticola as possible cause of his condition.). Moxifloxacin 400 mg i.v. q.d. was started empirically and he was discharged from hospital 13 days later without any sequels; apart from his previous drug regiment and therapy for Hellicobacter pylori gastritis found via gastric biopsy.



Though before 2006, the publications of human R. planticola infection were rare, after that year the report about that pathogen is steadily increasing (Graph 1.) Due to similarities with Klebsiella spp., microbiological diagnosis may be difficults3. Thus, one may argue the small number of the reports before 2006 with the diagnostic methods (e.g. the broad introduction of matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS), which is considered as the best diagnostic method for Raoultella spp.)3-5 In our patient Vitek 2 system was used for microbiological identification.


Graph 1. Returning resutls on National Medical Library PubMed ®  Database on  MeSH term “Raoultella planticola“ (search 25/01/2022)2.

Sixty-seven (67) out of the 144 publications on the subject are about infection on humans. Most of them (42) are case reports and only 12 regards paediatric population. In total the literature mention 309 cases. Raoultella planticola and Raoultella ornithinolytica are the most frequently encountered human pathogens3. The reservoir of Raoultella seems to be gastrointestinal tract and upper respiratory tract. Yet, the majority (127) of reported cases are urinary tract infections, while respiratory (mostly pneumonia) and abdominal infections (appendicitis, cholangitis, cholecystitis, pancreatitis, liver abscess) are following. However other locations are also mentioned (endocarditis, arthritis, conjunctivitis, cellulitis, prostatitis, mastitis), and severe (peritonitis, bacteremia sepsis) and fatal cases can arise3-6. Since most of the infections are related to immunocompromised patients (malignancy, diabetes mellitus) or patients with multiple co-morbidities, R. planticola is considered an opportunistic pathogen. Raoultella spp. are intrinsically resistant to penicillins, due to the expression of a broad-spectrum β-lactamase3. Yet, resistant strains such as AmpC β-lactamases, extended spectrum beta-lactamase (ESBL) or carbapenemase producing started to emerge. Unfortunately, the available literature on the subject in limited. Quinolones, aminoglycosides, tetracyclines, fosfomycin, nitrofurantoin, and polymyxins are some of the antibiotics recorded in the published reports. In our case, a multisensitive R.planticola was identified; thus antibiotic therapy with moxifloxacin was effective in eradicating it.


R. planticola is mainly reported as opportunistic infection. Yet, resistant to antibiotic strains could also be found. Thus, thorough investigation is needed whenever this pathogen is identified, so as to exclude possible undiagnosed co-morbidities (malingnancy) and to assure that proper antibiotic therapy is given.


Addittional materials: No


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Authors’ contributors:

MA:case management, data collection, final review, AT: manuscript draft, literature review analysis, final review, SCh: data collection, literature research, final review, DT: data collection, literature research, fnal review. All authors read and approved the final manuscript.


Not applicable

Availability of supporting data:

Not applicable.

Ethical approval and consent to participate:

No IRB approval required, patient’s consent obtained.

Competing interests:

The authors declare that they have no competing interests.



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Citation: Myrou A, Aslanidis Th, Savopoulos Ch, Didangelos T. Raoultella planticola _an emerging pathogen? Case report and literature review.Greek e j Perioper Med. 2022;21(a): 51-56.


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