Combination of Tigecycline and Levofloxacin for Successful Treatment of Nosocomial Pneumonia Caused by New Delhi Metallo-β-Lactamase-1-Producing Raoultella planticola

Abstract

Raoultella planticola is a gram-negative bacterium that rarely causes diseases in humans. Here, we present a case of hospital-acquired pneumonia caused by R. planticola that likely originated in the gastrointestinal tract. To the best of our knowledge, this is the second report describing the detection of the gene New Delhi Metallo-β-lactamase-1 (bla_NDM-1) in multidrug-resistant R. planticola. Clinical samples were collected for bacterial culture and antimicrobial susceptibility testing from a patient during hospitalization. The presence of bla_NDM-1 was detected by PCR and sequencing. An NDM-1-positive R. planticola was isolated from the sputum and stool of the same patient. Further findings confirmed that bla_NDM-1 was located on a plasmid. Isolates from the sputum and stool cultures were identical, suggesting that the R. planticola may have originated in the gastrointestinal tract. The patient completely recovered and was discharged after treatment with tigecycline combined with levofloxacin, for a week. In conclusion, R. planticola is a possibly underestimated pathogen that contributes to the spread of the bla_NDM-1 gene. Early and precise identification of this pathogen can lead to better prognosis of the associated infections and an improved approach to controlling the spread of carbapenemase-resistant gram-negative bacteria.

Introduction

Raoultella planticola, originally known as Klebsiella planticola, was first described by Bagley et al. as a group of organisms isolated primarily from botanical and aquatic environments.¹ The phylogenetic analyses of Klebsiella species were performed in 2001 by Drancourt et al., after which the term K. planticola was replaced by R. planticola based on the comparative analysis of the 16S rRNA and rpoB genes.² R. planticola is a gram-negative, aerobic, oxidase-negative, nonmotile, and encapsulated bacterium commonly found in water, soil, and the aquatic environment. Occasionally, it is also found in mammalian mucosae. The first invasive infection caused by Raoultella spp. in humans was reported by Freney et al.³ More than 20 cases have been reported thereafter, and although carbapenem resistance was rarely observed, these cases had much poorer outcomes than the cases in which the infections were caused by bacteria that were susceptible to carbapenem strains. In this study, we report a case of pneumonia associated with a New Delhi Metallo-β-lactamase-1 (NDM-1)-producing R. planticola. The patient recovered completely after receiving a combination therapy of tigecycline and levofloxacin.

Case Presentation

This study was performed in China, with approval from the Ethics Committee of Zhejiang University. Written informed consent was obtained from the patient not only for sampling but also for publication of the case. Medical records were reviewed for administration of antimicrobial therapy and determination of patient outcome.

The patient was a 74-year-old man from a village in Zhejiang Province. On June 16, 2014, the patient was admitted to the hospital for fever and cough. He was hospitalized for 25 days and discharged on July 11, 2014. He underwent subtotal gastrectomy and Billroth I anastomosis for perforation of a duodenal ulcer and acute peritonitis since 4 weeks. His sputum and stool were sampled for isolation of bacteria and for antimicrobial susceptibility testing. Carbapenem-resistant isolates were collected and investigated further.

Species identification was performed using the MicroScan WalkAway 40 S1 identification system (Dade Behring, Deerfield, IL). The 16s rDNA sequences were also analyzed to confirm the species identity. Susceptibility of the isolates to antimicrobial therapy was determined using the E-test methodology (BioMerieux SA, La Balme-les-Grottes, France). The modified Hodge test was performed to screen for carbapenemases. These results were interpreted according to the 2014 Clinical and Laboratory Standards Institute recommendations and guidelines. R. planticola isolates from the sputum and stool samples were subjected to pulsed-field gel electrophoresis (PFGE), according to previously reported protocols.⁴ The location of bla_NDM-1 was determined using the PFGE-S1 nuclease method. Separation of large fragments after restriction enzyme digestion was performed using PFGE, using a Bio-Rad CHEF Mapper XA system (Bio-Rad, CA) with an initial switch time of 2.16 sec and a final switch time of 63.8 sec for a run time of 18 hr. Southern hybridization was performed with a 560-bp segment of the bla_NDM-1 gene as a probe, using the Roche digoxigenin labeling and NBT/BCIP coloration system (Roche Biochemicals, Mannheim, Germany). Conjugation experiments were carried out by solid surface methods, with sodium azide-resistant E. coli J53 as the recipient. Transconjugants were selected on Luria-Bertani agar plates containing sodium azide (100 mg/L) and ampicillin (100 mg/L), and then confirmed by PCR amplification of bla_NDM-1 for NDM-1-positive donors and bla_OXA-30 gene for NDM-1-negative donors.

On admission, the patient was coughing up large amounts of sputum and had high fever. Computed tomography (CT) imaging revealed pulmonary infiltration and pleural effusion in both sides of the chest. The patient was empirically treated with broad-spectrum antibiotics (4,500 mg of piperacillin/tazobactam Q8H) and expectorants before evaluation for pneumonia. Four days later, the results of sputum culture remained positive for R. planticola, which showed intermediate resistance to levofloxacin, but complete resistance to ampicillin, ceftriaxone, ceftazidime, trimethoprim–sulfamethoxazole, and several other antimicrobial agents (Table 1). Based on the clinical manifestations of the patient and the results of laboratory examinations, piperacillin/tazobactam was replaced by 500 mg of levofloxacin QD. After 5 days of treatment, the symptoms had not alleviated and the body temperature of patient was fluctuating. Subsequent samples of stool and sputum continued to show R. planticola isolates that were susceptible to tigecycline. Therefore, 50 mg of tigecycline Q12H was added intravenously (double for the first dose) in combination with levofloxacin. The overall symptoms of the patient improved along with reduced sputum production and normal body temperature 3 days later. After treatment for a week, the neutrophil count of the patient normalized and his C-reactive protein levels decreased. CT imaging revealed significant clearing of the chest, and the patient was eventually discharged with relieved symptoms and a stable body temperature. CT imaging performed 2 weeks after discharge revealed complete absorption and resolution of effusions. 16S rDNA sequence analysis confirmed that the isolated bacteria were R. planticola.

Table 1.

Antibiogram of Raoultella planticola Isolated from Sputum Culture

Antimicrobial agents	MIC (μg/ml)
Ampicillin	≥32
Ampicillin/sulbactam	≥32
Amikacin	4
Aztreonam	≥64
Ciprofloxacin	≥4
Cefotetan	≥64
Ceftriaxone	≥64
Cefazolin	≥64
Nitrofurantoin	128
Gentamicin	≤1
Imipenem/cilastatin	≥16
Levofloxacin	4
Trimethoprim–sulfamethoxazole	≥320
Ceftazidime	≥64
Tobramycin	8
Tigecycline	1
Cefepime	16

Discussion

To understand the mechanisms of carbapenem resistance, PCR and sequencing assays were performed to identify carbapenemase genes (bla_KPC, bla_IMP, bla_VIM, bla_NDM, and bla_OXA-48). The bla_NDM-1 gene was identified in isolates from sputum and stool samples of the same patient. PFGE analysis of these isolates showed identical gel patterns, suggesting that they were derived from the same strain (Fig. 1A). S1-nuclease PFGE analysis showed that isolates from both the samples contained the same plasmid of ca. 50 kb (Fig. 1B). Furthermore, Southern blot hybridization confirmed that the bla_NDM-1 gene was located on this plasmid (Fig. 1C).

FIG. 1.

PFGE analysis of Raoultella planticola shows (A) XbaI-digested chromosome fragments separated by PFGE; (B) S1-nuclease-digested plasmid profiles separated by PFGE; and (C) S1-nuclease-digested plasmid profiles hybridized with a bla_NDM-1-specific probe. Lane M: PFG marker; lane 1: sample from the sputum; lane 2: sample from the stool. The arrows show the locations of bla_NDM-1 genes. PFGE, pulsed-field gel electrophoresis.

In this report, we described a case of pneumonia caused by R. planticola in a 74-year-old man with a history of duodenal ulcer perforation and subtotal gastrectomy. The patient eventually recovered after receiving intravenous tigecycline and levofloxacin. After a thorough literature review, we found only 23 cases of R. planticola infections from 1984 to 2015 (Table 2). These included five cases of bacteremia,^3,5–8 four cases of cholangitis,^9–12 three cases of soft tissue infections,^13–15 four cases of pneumonia,^4–6,8 two cases of cholecystitis,^16,17 three cases of cystitis,^18–20 one case of pancreatitis,²¹ and one case of conjunctivitis.²² The ages of patients who developed a clinically relevant R. planticola infection ranged from 30 to 89 years. In addition, we found that patients in a large proportion of the reported cases had a history of recent trauma, namely surgery or invasive procedures (59.1%). Several patients also reported a history of tumors, recent chemotherapy, or immunosuppressive treatment (43.5%).

Table 2.

Summary of Previous Case Reports

Author (reference)	Age (y)/gender	Clinical diagnosis	Comorbidity	Invasive procedure	Treatment	Outcome
Freney et al.³	47/Male	Bacteremia	Mitral stenosis, infective endocarditis	Mitral valve replacement	Cefotaxime, tobramycin	Recovered
Freney et al.⁵	69/NA	Bacteremia	Mitral stenosis, infective endocarditis	Mitral valve replacement	Cefotaxime, tobramycin	Recovered
Freney et al.⁵	57/NA	Pneumonia, sepsis	Coronary artery disease	Postcoronary artery bypass graft	Cefotaxime	Recovered
Alves et al.²¹	45/Male	Pancreatitis and retroperitoneal abscess	Alcoholism, pneumonia	Exploratory laparotomy	Imipenem, amikacin	Recovered
Castanheira et al.⁶	83/Female	Pneumonia	None	NA	None	Death
Castanheira et al.⁶	64/Male	Bacteremia	B lymphoblastic leukemia	Surgical abscess debridement	Daptomycin	Death
O'Connell et al.¹³	30/Male	Cellulitis	None	Hammer crush injury	Benzylpenicillin, flucloxacillin, clindamycin, ciprofloxacin	Recovered
Wolcott et al.¹⁴	66/Male	Surgical site infection	Coronary artery disease, hypertension, hyperlipidemia	Open reduction internal fixation	Ertapenem	Recovered
Yokota et al.⁹	65/Male	Cholangitis, bacteremia	Adenocarcinoma of the neck	ERCP	Meropenem, piperacillin/tazobactam	Recovered
Hu et al.¹⁰	59/Male	Cholangitis, bacteremia	Pancreatic carcinoma	ERCP	Piperacillin/tazobactam	Recovered
Kim et al.¹⁵	66/Male	Necrotizing fasciitis	Coronary artery disease, diabetes	Abdominal trauma	Ceftriaxone, levofloxacin, tigecycline	Recovered
Teo et al.¹⁶	62/Female	Cholecystitis	Celiac disease, IBD	None	Co-amoxiclav, surgery	Recovered
Olson et al.¹⁸	89/Male	Cystitis	Coronary artery disease, hypertension	None	Ciprofloxacin	Recovered
Puerta-Fernandez et al.⁷	63/Male	Bacteremia, gastroenteritis	Posterior pituitary adenoma	None/Ate fish	Cefotaxime	Recovered
Tseng et al.⁸	77/Male	Pneumonia, septic shock	Nonsmall-cell lung cancer	None	Levofloxacin, meropenem, colistin	Death
Tseng et al.⁸	57/Male	Catheter-related bacteremia	Nonsmall-cell lung cancer, chemotherapy	Catheterization	Ceftazidime, levofloxacin, gentamicin	Recovered
Zuberbuhler et al.²²	58/Female	Bacterial conjunctivitis	None	None	Chloramphenicol	Recovered
Ershadi et al.¹⁷	49/Male	Cholecystitis, severe sepsis	Alcohol abuse, alcoholic cirrhosis, diabetes	None	Vancomycin, piperacillin/tazobactam, tigecycline	Recovered
Lam et al.¹¹	56/Female	Cholangitis	Nonsmall-cell lung cancer, chemotherapy	Seafood consumption	Ceftriaxone, ciprofloxacin	Recovered
Koukoulaki et al.¹⁹	67/Male	Cystitis, prostatitis	Immunoglobulin-A nephropathy	Renal transplant	Ciprofloxacin	Recovered
Salmaggi et al.¹²	70/Male	Cholangitis, sepsis	Pancreatic adenocarcinoma, chemotherapy	Biliary stenting	Ciprofloxacin, metronidazole	Recovered
Xu et al.⁴	60/Male	Pneumonia Acute myeloid leukemia	Septic shock and respiratory failure	None	Cefoperazone/sulbactam, imipenem/cilastatin, levofloxacin, tigecycline	Death
Yoon et al.²⁰	16 m/Male	Cystitis	Rhabdomyosarcoma of the bladder neck,	None	Cefotaxime, ampicillin/sulbactam	Recovered

NA, not available.

In the current case, the elderly patient had a history of gastroduodenal ulcer perforation, gastrectomy, and use of broad-spectrum antimicrobials. This factor may have led to an imbalance of the intestinal flora, which facilitated the emergence of multidrug-resistant bacteria. Laboratory tests showed that both the sputum culture and stool culture were NDM-1 positive for R. planticola, which was confirmed by the PFGE assay. This finding suggested a scenario of possible intestinal colonization of R. planticola in this patient. His pneumonia might be attributed to bacterial translocation or aspiration, accompanied by risk factors such as previous gastrointestinal operation, older age, a feeding tube procedure, or treatment with histamine H-2 antagonists.

To the best of our knowledge, this is the second reported case of bla_NDM-1 being detected in R. planticola. The first case was reported in a Klebsiella pneumoniae strain that caused a urinary tract infection in a Swedish patient who had travelled to New Delhi, India, in 2009.²³ The resistance gene NDM-1 can be produced by various pathogens and can be transmitted via a plasmid to other members of the same species or to different bacterial species. The NDM-1 gene has been previously described in E. coli, Enterobacter cloacae, Acinetobacter baumannii, and Citrobacter rodentium across several countries. One study reported that five NDM-1 carbapenemase-producing isolates were identified from 186 carbapenem-resistant Enterobacteriaceae isolates recovered from our hospital between January and September 2013.²⁴ NDM-1-producing pathogens are resistant to ∼200 kinds of antimicrobial agents. Antimicrobial susceptibility tests indicate that NDM-1 is somewhat sensitive to polymyxin and tigecycline, and that some strains are sensitive to aztreonam, gentamicin, or ciprofloxacin. It has been reported that polymyxin and tigecycline inhibit NDM-1 with ∼80–90% efficiency.²⁵ Current research and meta-analysis of randomized controlled trials have suggested the use of combination therapy for a curative effect, but the mortality rate is not superior to that observed when monotherapy is used. However, an observational study of carbapenem-resistant Klebsiella pneumoniae indicated that the use of combination therapy appears to be associated with improved survival in bacteremia due to KPC-producing K. pneumoniae.²⁶ The patient in the current case recovered after receiving a combination therapy of tigecycline and levofloxacin, confirming the results of the susceptibility tests and the effectiveness of combination therapy.

In conclusion, we present a case of bla_NDM-1 in R. planticola, which was cured by treatment with tigecycline. R. planticola is a rare and possibly underestimated pathogen in terms of its pathogenicity, and with potential gain of the bla_NDM-1 gene, it might produce “superbugs” that can pose a threat to public health. Early detection of this pathogen is, therefore, critical to the selection of effective therapies.

Footnotes

Acknowledgment

This work was supported by a special fund for medical and health program of Zhejiang Province (2010KYB045).

Disclosure Statement

No competing financial interests exist.

References

Bagley

S.T.

, Seidler

R.J.

, and Brenner

D.J.

. 1981. Klebsiella planticola sp. nov.: a new species of Enterobacteriaceae found primarily in nonclinical environments. Curr. Microbiol., 6:105–109.

Drancourt

, Bollet

, Carta

, and Rousselier

. 2001. Phylogenetic analyses of Klebsiella species delineate Klebsiella and Raoultella gen. nov., with description of Raoultella ornithinolytica comb. nov., Raoultella terrigena comb. nov. and R. planticola comb. nov. Int. J. Syst. Evol. Micr., 51:925–932.

Freney

, Fleurette

, Gruer

L.D.

, Desmonceaux

, Gavini

, and Leclerc

. 1984. Klebsiella trevisanii colonisation and septicaemia. Lancet, 1:909.

, Xie

, Fu

, Zhou

, and Zhou

. 2015. Nosocomial pneumonia caused by carbapenem-resistant Raoultella planticola: a case report and literature review. Infection, 43:245–248.

Freney

, Gavini

, Alexandre

, Madier

, Izard

, Leclerc

, and Fleurette

. 1986. Nosocomial infection and colonization by Klebsiella trevisanii. J. Clin. Microbiol., 23:948–950.

Castanheira

, Deshpande

L.M.

, DiPersio

J.R.

, Kang

, Weinstein

M.P.

, and Jones

R.N.

. 2009. First descriptions of blaKPC in Raoultella spp. (R. planticola and R. ornithinolytica): report from the SENTRY Antimicrobial Surveillance Program. J. Clin. Microbiol., 47:4129–4130.

Puerta-Fernandez

, Miralles-Linares

, Sanchez-Simonet

M.V.

, Bernal-Lopez

M.R.

, and Gomez-Huelgas

. 2013. R. planticola bacteraemia secondary to gastroenteritis. Clin. Microbiol. Infec., 19:E236–E237.

Tseng

S.P.

, Wang

J.T.

, Liang

C.Y.

, Lee

P.S.

, Chen

Y.C.

, and Lu

P.L.

. 2014. First Report of blaIMP-8 in R. planticola. Antimicrob. Agents Chemother., 58:593–595.

Yokota

, Gomi

, Miura

, Sugano

, and Morisawa

. 2012. Cholangitis with septic shock caused by R. planticola. J. Med. Microbiol., 61:446–449.

10.

A.Y.

, Leslie

K.A.

, Baskette

, and Elsayed

. 2012. R. planticola bacteraemia. J. Med. Microbiol., 61:1488–1489.

11.

Lam

P.W.

, and Salit

I.E.

. 2014. R. planticola bacteremia following consumption of seafood. Can. J. Infect. Dis. Med., 25:e83–e84.

12.

Salmaggi

, Ancona

, Olivetti

, Pagliula

, and Ramirez

G.A.

. 2014. R. planticola-associated cholangitis and sepsis: a case report and literature review. QJM Int. J. Med., 107:911–913.

13.

O'Connell

, Kelly

, and NiRiain

. 2010. A rare case of soft-tissue infection caused by R. planticola. Case. Rep. Med., 2010: PMID: 20811592; DOI: 10.1155/2010/134086.

14.

Wolcott

, and Dowd

. 2010. Molecular diagnosis of R. planticola infection of a surgical site. J. Wound Care, 19:329–332.

15.

Kim

S.H.

, Roh

K.H.

, Yoon

Y.K.

, Kang

D.O.

, Lee

D.W.

, Kim

M.J.

, and Sohn

J.W.

, 2012. Necrotizing fasciitis involving the chest and abdominal wall caused by R. planticola. BMC Infect. Dis., 12:59.

16.

Teo

, Wild

, Ray

, and Chadwick

. 2012. A rare case of cholecystitis caused by R. planticola. Case. Rep. Med., 2012:601641.

17.

Ershadi

, Weiss

, Verduzco

, Chia

, and Sadigh

. 2014. Emerging pathogen: a case and review of R. planticola. Infection, 42:1043–1046.

18.

Olson

D.S.

Jr , Asare

, Lyons

, and Hofinger

D.M.

. 2013. A novel case of R. planticola urinary tract infection. Infection, 41:259–261.

19.

Koukoulaki

, Bakalis

, Kalatzis

, Belesiotou

, Papastamopoulos

, Skoutelis

, and Drakopoulos

. 2014. Acute prostatitis caused by R. planticola in a renal transplant recipient: a novel case. Transpl. Infect. Dis., 16:461–464.

20.

Yoon

J. H.

, Ahn

Y.H.

, Chun

J.I.

, Park

H.J.

, and Park

B.-K.

. 2015. Acute Raoultella planticola cystitis in a child with rhabdomyosarcoma of the bladder neck. Pediatr. Int., 57:985–987.

21.

Alves

M.S.

, Riley

L.W.

, and Moreira

B.M.

. 2007. A case of severe pancreatitis complicated by R. planticola infection. J. Med. Microbiol., 56:696–698.

22.

Zuberbuhler

, Abedin

, and Roudsari

. 2014. A novel case of chronic conjunctivitis in a 58-year-old woman caused by Raoultella. Infection, 42:927–929.

23.

Yong

, Toleman

M.A.

, Giske

C.G.

, Cho

H.S.

, Sundman

, Lee

, and Walsh

T.R.

. 2009. Characterization of a new metallo-β-lactamase gene, blaNDM-1, and a novel erythromycin esterase gene carried on a unique genetic structure in Klebsiella pneumoniae sequence type 14 from India. Antimicrob. Agents Chemother., 53:5046–5054.

24.

Yang

, Fang

, Fu

, Du

, Shen

, and Yu

. 2015. Dissemination of NDM-1-producing Enterobacteriaceae mediated by the IncX3-type plasmid. PLoS One, 10:1–9.

25.

Kumarasamy

K.K.

, Toleman

M.A.

, Walsh

T.R.

, Bagaria

, Butt

, Balakrishnan

, Chaudhary

, Doumith

, Giske

C.G.

, Irfan

, Krishnan

, Kumar

A.V.

, Maharjan

, Mushtaq

, Noorie

, Paterson

D.L.

, Pearson

, Perry

, Pike

, Rao

, Ray

, Sarma

J.B.

, Sharma

, Sheridan

, Thirunarayan

M.A.

, Turton

, Upadhyay

, Warner

, Welfare

, Livermore

D.M.

, and Woodford

. 2010. Emergence of a new antibiotic resistance mechanism in India, Pakistan, and the UK: a molecular, biological, and epidemiological study. Lancet Infect. Dis., 10:597–602.

26.

Qureshi

Z.A.

, Paterson

D.L.

, Potoski

B.A.

, Kilayko

M.C.

, Sandovsky

, Sordillo

, Polsky

, Adams-Haduch

J.M.

, and Doi

. 2012. Treatment outcome of bacteremia due to KPC-producing Klebsiella pneumoniae: superiority of combination antimicrobial regimens. Antimicrob. Agents Chemother., 56:2108–2113.