Advertisement

Pantoea dispersa bacteremia in an immunocompetent patient: a case report and review of the literature

  • Nobuhiro Asai
  • Yusuke Koizumi
  • Atsuko Yamada
  • Daisuke Sakanashi
  • Hiroki Watanabe
  • Hideo Kato
  • Arufumi Shiota
  • Mao Hagihara
  • Hiroyuki Suematsu
  • Yuka Yamagishi
  • Hiroshige MikamoEmail author
Open Access
Case report

Abstract

Background

Pantoea is a Gram-negative, non-encapsulated, non-spore-forming, ubiquitous straight rod which can be isolated from geographical and ecological sources such as plant surfaces, buckwheat seeds, human feces, and the environment. The genus Pantoea is a rare pathogen in a clinical setting, and is divided into 20 different species such as Pantoea agglomerans, Pantoea ananatis, Pantoea deleyi, Pantoea dispersa, Pantoea septica, Pantoea stewartii or Pantoea rwandensis. Pantoea dispersa has been reported to cause other infections, including respiratory infections, neonatal sepsis, and bloodstream infections. We report a case of Pantoea dispersa bacteremia caused by acute cholangitis. This is the first case report of Pantoea dispersa bacteremia caused by acute cholangitis as far as we had searched.

Case presentation

A 38-year-old Japanese woman suffered from acute cholangitis; a blood culture showed that Gram-negative rod was positive. The treatment was successful with intravenously administered meropenem, and it was switched to orally administered levofloxacin according to microbiological susceptibility. The organism was identified as Pantoea dispersa by both genetic investigation by 16S ribosomal RNA and additional biochemical tests. To the best of our knowledge, this is the first case report of Pantoea dispersa bacteremia caused by acute cholangitis.

Conclusion

The epidemiology and clinical features of Pantoea dispersa are still unknown. More cases of infections caused by Pantoea dispersa might be revealed with advancing technical methods, such as matrix-assisted laser desorption/ionization time-of-flight mass spectrometry or 16S ribosomal RNA analysis. Physicians must know that a variety of infections caused by Pantoea dispersa could occur in immunocompromised as well as immunocompetent patients.

Keywords

Pantoea dispersa Bacteremia Gram-negative rod Cholangitis 

Abbreviations

CLSI

Clinical and Laboratory Standards Institute

CPZ

Cefoperazone

CT

Computed tomography

LVFX

Levofloxacin

MALDI-TOF-MS

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

MEPM

Meropenem

rRNA

Ribosomal RNA

SBT

Sulbactam

Background

Pantoea is a Gram-negative, non-encapsulated, non-spore-forming, ubiquitous straight rod which can be isolated from geographical and ecological sources such as plant surfaces, buckwheat seeds, human feces, and the environment [1, 2]. The genus Pantoea is a rare pathogen in a clinical setting, and is divided into 20 different species named Pantoea eucalyptii, Pantoea agglomerans, Pantoea vagans, Pantoea conspicua, Pantoea deleyi, Pantoea anthophila, Pantoea brenneri, Pantoea ananatis, Pantoea allii, Pantoea stewartii, Pantoea cypripedii, Pantoea calida, Pantoea gavinae, Pantoea dispersa, Pantoea septica, Pantoea wallisii, Pantoea eucrina, Pantoea rodasii, Pantoea rwandensis, and Pectobacterium carotovorum [2, 3]. P. agglomerans is the most prominent species in humans, formerly named Enterobacter agglomerans.

P. dispersa has been reported to cause other infections, including respiratory infection [4], neonatal sepsis [5], and bloodstream infection [6]. This microbe has been known to cause infections in immunocompromised patients but not in immunocompetent patients. Here we report a case of P. dispersa bacteremia caused by acute cholangitis. This is the first case report of P. dispersa bacteremia caused by acute cholangitis, as far as we could search.

Case presentation

A 38-year-old Japanese woman came to our institute with a complaint of epigastric pain after meals. She had no medical history and no exposures to plants or animals prior to her hospital stay or invasive procedures. She never smoked tobacco and was not an alcohol consumer. She was diagnosed as having acute cholangitis induced by stone based on symptoms and laboratory findings (Table 1), and was admitted (Fig. 1). Her body temperature was 37.1 °C, blood pressure 97/57 mmHg, and heart rate 85/minute. She did not exhibit any jaundice. An abdominal examination revealed tenderness on the epigastric portion. No rebound tenderness was confirmed. Her cardiac, respiratory, and neurological examinations were normal. Abdominal computed tomography (CT) findings showed gallstones with gallbladder wall thickening (Fig. 2). Antibiotic therapy of sulbactam (SBT)/cefoperazone (CPZ) was started empirically at the same time. When undergoing endoscopic nasobiliary drainage, she had a high fever and two sets of blood cultures were obtained on day 6. Growth of Gram-negative rods was reported in both aerobic and anaerobic blood cultures within 24 hours on BACTEC™ (BD, Tokyo, Japan). Antibiotic therapy of meropenem (MEPM) was started empirically. Our patient’s clinical condition and laboratory data improved rapidly. After 3 days of intravenously administered MEPM, the antibiotic therapy was switched to orally administered levofloxacin (LVFX) 500 mg daily for another 7 days according to microbiological sensitivity. The infection did not recur and she was discharged on day 28. During 1 year, recurrence of the infection was not observed.
Table 1

Laboratory findings on admission

WBC

13,200/μL

CK

36 IU/L

Neu

92.4%

γ-GTP

129 IU/L

Lym

5.3%

Amy

61 IU/L

Mono

1.9%

TP

7.3 g/dL

Eos

0.1%

Alb

4.2 g/dL

RBC

410 × 104/μL

BUN

9.6 mg/dL

Hb

11.7 g/dL

Cre

0.6 mg/dL

Plt

19.2 × 104/μL

Na

136 mmol/L

AST

30 IU/L

K

4.1 mmol/L

ALT

63 IU/L

Cl

98 mmol/L

T-Bil

1.1 mg/dL

Ca

9.1 mg/dL

LDH

180 IU/L

Glu

66 mg/dL

ALP

341 IU/L

CRP

17.7 mg/dL

Alb albumin, ALP alkaline phosphatase, ALT alanine aminotransferase, Amy amylase, AST aspartate aminotransferase, BUN blood urea nitrogen, Ca calcium, CK creatine kinase, Cl chlorine, Cre creatinine, CRP C-reactive protein, Eos eosinophil, γ-GTP γ-glutamyltransferase, Glu glucose, Hb hemoglobin, K potassium, LDH lactate dehydrogenase, Lym lymphocyte, Mono monocyte, Na sodium, Neu neutrophil, Plt platelet, RBC red blood cell count, T-Bil total bilirubin, TP total protein, WBC white blood cell count

Fig. 1

The clinical course of this case. CPZ cefoperazone, ERBD endoscopic retrograde biliary drainage, LVFX levofloxacin, MEPM meropenem, SBT sulbactam

Fig. 2

Abdominal computed tomography shows gallstones with gallbladder wall thickening

First, the pathogen by positive blood culture was identified as Klebsiella ozaenae by means of a MALDI Biotyper® (Bruker Daltonics). Subsequently, genetic investigation by 16S ribosomal RNA (rRNA) analysis was performed in order to identify this organism. Finally, the pathogen was identified as P. dispersa with 100% homology (1343 of 1343 bases) on the EZ taxonomy database (http://www.ezbiocloud.net/eztaxon). We also conducted additional biochemical tests using API® 50 CH kit, according to previous reports to confirm the isolate as P. dispersa. The organism had no activities of esculin and salicin, and had activities of lactose, melibiose, and gentiobiose, which were consistent with P. dispersa [6].

Antimicrobial susceptibility testing was performed according to Clinical and Laboratory Standards Institute (CLSI) criteria for Enterobacteriaceae [7] using the newly developed, fully automated microbiology system, RAISUS (Nissui Pharmaceuticals Co., Ltd., Tokyo). The organism was susceptible to all antimicrobial agents tested, including ampicillin, cefazolin, gentamicin, LVFX, and trimethoprim-sulfamethoxazole (Table 2).
Table 2

Antimicrobial susceptibility of Pantoea dispersa isolated from blood culture

Antimicrobial agents

MIC (μg/mL)

Interpretation

Ampicillin

≤ 8

S

Minocycline

≤ 4

S

Amikacin

≤ 4

S

Aztreonam

≤ 1

S

Ceftazidime

≤ 1

S

Cefazolin

8

R

Cefepime

≤ 2

S

Cefmetazole

≤ 16

S

Ciprofloxacin

≤ 0.063

S

Cefotiam

≤ 2

 

Cefotaxime

≤ 1

S

Fosfomycin

≤ 64

 

Imipenem

≤ 0.5

S

Levofloxacin

≤ 0.125

S

Piperacillin

≤ 16

S

Trimethoprim/sulfamethoxazole

≤ 2/38

S

Meropenem

≤ 0.125

S

Tazobactam/piperacillin

≤ 4/4

S

MIC minimum inhibitory concentration, R resistant, S susceptible

Discussion

Pantoea is a genus of Gram-negative bacteria of the family Enterobacteriaceae that was recently separated from the Enterobacter genus. They have also recently been shown to cause infections in humans [1, 2, 3, 4, 5, 6]. However, only a limited number of clinical cases with bacteria belonging to this genus have been described. Thus, there is not enough information on its pathogenic mechanism.

A total of five cases of infections by P. dispersa including ours have previously been reported as shown in Table 3. Two of the five cases were neonates, and the other three cases were adults. The sites of infections varied such as respiratory or blood stream infections. As for the underlying diseases of the three adults, one patient with leukemia was immunocompromised and the other two were immunocompetent. In terms of the outcomes, all patients were improved. Epidemiology and clinical features of P. dispersa infection are still unknown due to its rarity and the difficulty in accurate identification. A previous report documented that more than 10% of clinical isolates of P. agglomerans were misidentified as species of the genus Enterobacter by the VITEK® MS system [8]. In the present case, the isolate was initially misidentified as Klebsiella ozaenae by MALDI Biotyper®. Finally, 16S rRNA analysis confirmed that the isolate was P. dispersa. More cases could be missed due to misidentifications as P. dispersa. A variety of infections caused by P. dispersa have been reported [4, 5, 6]. More cases of infections caused by P. dispersa might be revealed with advancing technical methods, such as matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) or 16S rRNA analysis.
Table 3

Previous reports of Pantoea dispersa infections

Author (year)

Sex

Age

Site of infection

Underlying disease

Treatment

Outcome

Schmid et al. (2003) [4]

F

71

Respiratory infection

Acute myeloid leukemia

CAM

AMPC/CVA

Improved

Hagiya and Otsuka (2014) [6]

M

64

Bloodstream infection

Bacteremia

DCM

DM

SSS

Cefepime

Improved

Mehar et al. (2013) [5]

ND

Neonate

Sepsis

Not described

TAZ/PIPC

AMK

Improved

Mehar et al. (2013) [5]

ND

Neonate

Sepsis

Not described

SBT/ABPC

AMK

Improved

Current case

F

38

Bacteremia

Cholangitis

Choledocholithiasis

Meropenem

Improved

AMK amikacin, AMPC/CVA amoxicillin/clavulanate, CAM clarithromycin, DCM dilated cardiomyopathy, DM diabetes mellitus, F female, M male, ND not described, SBT/ABPC sulbactam/ampicillin, SSS sick sinus syndrome, TAZ/PIPC tazobactam/piperacillin

All species of the genus Pantoea can be isolated from feculent material, plants, and soil [2]. However, our patient had no contact with these sources. The isolate was susceptible to amikacin, cefepime, cefotaxime, ciprofloxacin, MEPM, and aztreonam, and resistant to cefazolin. Fortunately, our patient survived because appropriate antibiotic therapy was rapidly started. These results were similar to those of previous reports [4, 5, 6]. Of note, P. dispersa bacteremia can occur not only in immunocompromised hosts but also in immunocompetent patients. Although all cases improved, the pathogenic and clinical importance of P. dispersa infection are unclear. Additional case reports of P. dispersa infections could help physicians understand the pathogenetic potential of this organism.

Conclusion

We experienced a case of P. dispersa bacteremia caused by acute cholangitis, which is the first report as far as we could search. Although P. dispersa could cause a variety of infections in immunocompromised as well as immunocompetent patients, some cases of P. dispersa infections might be misdiagnosed as other pathogens infection. More cases of infections by P. dispersa should be collected and examined to clarify the epidemiology of P. dispersa infections.

Notes

Acknowledgements

We are grateful for the diligent and thorough critical reading of our manuscript by Dr Yoshihiro Ohkuni, Chief Physician, Taiyo and Mr John Wocher, Executive Vice President and Director, International Affairs/International Patient Services, Kameda Medical Center (Japan).

Funding

None declared.

Availability of data and materials

The data that support the findings of this study are available from the corresponding author upon reasonable request.

Authors’ contributions

NA, YK, HW, YY, and HM carried out the clinical follow up. NA drafted the manuscript. AY, DS, and HS performed microbial testing and NA, YK, HW, YY, and HM performed laboratory analysis. HK, AS, and MH supervised the antibiotic and antiviral therapy. All authors read and approved the final manuscript.

Ethics approval and consent to participate

Not applicable.

Consent for publication

Written informed consent was obtained from the patient for publication of this case report and any accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal.

Competing interests

The authors declare that they have no competing interests.

Publisher’s Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

References

  1. 1.
    Gavini F, Mergaert J, Beji A, Mielcarek C, Izard D, Kersters K, et al. Transfer of Enterobacter agglomerans (Beijerinck 1888) Ewing and Fife 1972 to Pantoea gen. nov. as Pantoea agglomerans comb. nov. and description of Pantoea dispersa sp. nov. Int J Syst Bacteriol. 1989;39:337–45.CrossRefGoogle Scholar
  2. 2.
    Walterson AM, Stavrinides J. Pantoea: insights into a highly versatile and diverse genus within the Enterobacteriaceae. FEMS Microbiol Rev. 2015;39:968–84.CrossRefGoogle Scholar
  3. 3.
    Mergaert J, Verdonck L, Kersters K. Transfer of Erwinia ananas (synonym, Erwinia uredovora) and Erwinia stewartii to the Genus Pantoea emend. as Pantoea ananas (Serrano1928) comb. nov. and Pantoea stewartii (Smith 1898) comb. nov., respectively, and Description of Pantoea stewartii subsp. indologenes subsp. nov. Int J Syst Bacteriol. 1993;43:162–73.CrossRefGoogle Scholar
  4. 4.
    Schmid H, Schubert S, Weber C, Bogner JR. Isolation of a Pantoea dispersa-like strain from a 71-year-old woman with acute myeloid leukemia and multiple myeloma. Infection. 2003;31:66–7.CrossRefGoogle Scholar
  5. 5.
    Mehar V, Yadav D, Sanghvi J, Gupta N, Singh K. Pantoea dispersa: an unusual cause of neonatal sepsis. Braz J Infect Dis. 2013;17:726–8.CrossRefGoogle Scholar
  6. 6.
    Hagiya H, Otsuka F. Pantoea dispersa bacteremia caused by central line-associated bloodstream infection. Braz J Infect Dis. 2014;18:696–7.CrossRefGoogle Scholar
  7. 7.
    Clinical and Laboratory Standards Institute. Performance standards for antimicrobial susceptibility testing;twenty-fifth informational supplement. M100-S25. Wayne: Clinical and Laboratory Standards Institute; 2015.Google Scholar
  8. 8.
    Richter SS, Sercia L, Branda JA, et al. Identification of Enterobacteriaceae by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry using the VITEK MS system. Eur J Clin Microbiol Infect Dis. 2013;32:1571–8.CrossRefGoogle Scholar

Copyright information

© The Author(s). 2019

Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.

Authors and Affiliations

  • Nobuhiro Asai
    • 1
    • 2
  • Yusuke Koizumi
    • 1
    • 2
  • Atsuko Yamada
    • 2
  • Daisuke Sakanashi
    • 2
  • Hiroki Watanabe
    • 1
    • 2
  • Hideo Kato
    • 2
  • Arufumi Shiota
    • 2
  • Mao Hagihara
    • 1
    • 2
  • Hiroyuki Suematsu
    • 2
  • Yuka Yamagishi
    • 1
    • 2
  • Hiroshige Mikamo
    • 1
    • 2
    Email author
  1. 1.Department of Clinical Infectious DiseasesAichi Medical University HospitalNagakuteJapan
  2. 2.Department of Infection Control and PreventionAichi Medical University HospitalNagakuteJapan

Personalised recommendations