Document Detail

Enterobacter cloacae infection of an expanded polytetrafluoroethylene femoral-popliteal bypass graft: a case report.
Jump to Full Text
MedLine Citation:
PMID:  20459698     Owner:  NLM     Status:  PubMed-not-MEDLINE    
INTRODUCTION: Enterobacter cloacae infections are common among burn victims, immunocompromised patients, and patients with malignancy. Most commonly these infections are manifested as nosocomial urinary tract or pulmonary infections. Nosocomial outbreaks have also been associated with colonization of certain surgical equipment and operative cleaning solutions. Infections of an aortobifemoral prosthesis, an aortic graft, and arteriovenous fistulae are noted in the literature. To our knowledge, this is the first isolated account of an E. cloacae infection of a femoral-popliteal expanded polytetrafluoroethylene bypass graft.
CASE PRESENTATION: A 68-year-old Caucasian man presented with fever and rest pain in the right lower extremity five months after the placement of a vascular expanded polytetrafluoroethylene graft for femoral-popliteal bypass. Computed tomography angiography demonstrated peri-graft fluid that was aspirated percutaneously with image guidance and cultured to reveal E. cloacae. The graft was revised and then removed. The patient completed a six-week course of ceftazidime and is currently without signs of infection. There were no other reports of E. cloacae graft infections in any patients receiving treatment in the same surgical suite within a month of this report.
CONCLUSION: Isolated cases of E. cloacae infection of surgical bypass grafts are rare (unique in this setting). Clinicians should have a high index of suspicion for device contamination in such cases and should consider testing for possible microbial reservoirs. Graft removal is required due to the formation of biofilm and the recent emergence of Enterobacteriaceae producing extended-spectrum beta-lactamase in community acquired infections.
Ian Musil; Vanessa Jensen; Jolyon Schilling; Boyd Ashdown; Tyler Kent
Related Documents :
1576288 - Aortic bypass graft infection due to aspergillus: report of a case and review.
21161358 - Porcine kobuvirus from pig stool in korea.
20978578 - Recurrent rupture of an infected aortic arch.
6458258 - Development of an infection-resistant vascular prosthesis.
8853768 - The safety and efficacy of ranitidine bismuth citrate in combination with antibiotics f...
20551098 - Reactive arthritis and other musculoskeletal sequelae following an outbreak of salmonel...
Publication Detail:
Type:  Journal Article     Date:  2010-05-09
Journal Detail:
Title:  Journal of medical case reports     Volume:  4     ISSN:  1752-1947     ISO Abbreviation:  J Med Case Rep     Publication Date:  2010  
Date Detail:
Created Date:  2010-05-20     Completed Date:  2011-07-14     Revised Date:  2012-05-16    
Medline Journal Info:
Nlm Unique ID:  101293382     Medline TA:  J Med Case Rep     Country:  England    
Other Details:
Languages:  eng     Pagination:  131     Citation Subset:  -    
Tucson Hospitals Medical Education Program, 1501 N, Campbell Avenue, PO Box 245066, Tucson, Arizona 85724-5066, USA.
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

Full Text
Journal Information
Journal ID (nlm-ta): J Med Case Reports
ISSN: 1752-1947
Publisher: BioMed Central
Article Information
Download PDF
Copyright ?2010 Musil et al; licensee BioMed Central Ltd.
Received Day: 10 Month: 11 Year: 2009
Accepted Day: 9 Month: 5 Year: 2010
collection publication date: Year: 2010
Electronic publication date: Day: 9 Month: 5 Year: 2010
Volume: 4First Page: 131 Last Page: 131
Publisher Id: 1752-1947-4-131
PubMed Id: 20459698
DOI: 10.1186/1752-1947-4-131

Enterobacter cloacae infection of an expanded polytetrafluoroethylene femoral-popliteal bypass graft: a case report
Ian Musil13 Email:
Vanessa Jensen23 Email:
Jolyon Schilling3 Email:
Boyd Ashdown3 Email:
Tyler Kent3 Email:
1College of Medicine, University of Arizona, 1501 N Campbell Avenue, Tucson AZ 85724, USA
2Department of Surgery, University of Arizona, 1501 N. Campbell Avenue, PO Box 245066 Tucson, Arizona 85724-5066, USA
3Tucson Hospitals Medical Education Program, 1501 N. Campbell Avenue, PO Box 245066, Tucson, Arizona 85724-5066, USA


Enterobacter cloacae infections are seen commonly in burn victims, immunocompromised patients, and patients with malignancy [1]. The urinary and pulmonary systems are the organ systems most commonly colonized in these patients. E. cloacae bacteremia can also occur depending on the extent of immunocompromise.

Outbreaks of coloacae infections are recorded in a number of hospital settings. Sporadic cases of E. cloacae infections have been linked to contaminated admixed intravenous fluids, total parenteral nutrition solutions, enteral feedings, infant formula, cardioplegic solution, and blood products [2-4]. Another potential reservoir for nosocomial bacteremia is the heparin flush solution used to irrigate certain intravascular devices continually. This fluid had been implicated as a reservoir for outbreaks of device-associated bacteremia in several instances [5].

Less commonly, outbreaks are linked to the colonization of devices such as long-term tunneled hemodialysis catheters. Buxton and colleagues reported an epidemic of E. cloacae infections that was associated with disposable transducer domes. During their initial setup the chambers and domes were contaminated by the hands of hospital personal who had handled contaminated transducer heads [6]. West and colleagues also reported E. cloacae sepsis resulting from transducer dome cracks. In this study, disposable transducer domes were being re-sterilized with resultant cracks in the dome membrane holding bacteria. Case series also document the colonization of entire operative suites that require extensive decontamination [4].

Case presentation

A 68-year-old male presents to a rural clinic with a two-week history of claudication and a one-day history of rest pain and fever. His past medical history was relevant for lower extremity arterial insufficiency and claudication in his right leg for which he underwent a right femoral-popliteal above the knee bypass using a 6mm expanded polytetrafluoroethylene (ePTFE) graft in May 2007. The graft was revised a month later in July 2007 when surveillance ultrasound revealed an occlusion. Intra-operative findings at that presentation included extensive calcific atherosclerotic disease and aggressive intimal hyperplasia in the popliteal artery. A small seroma around the distal anastomosis was discovered and evacuated at that time. There was no evidence of graft infection after thrombectomy and revision. Our patient was started on coumadin to maintain graft patency. His initial recovery was unremarkable.

Four months later, our patient began to experience claudication for two weeks and then developed rest pain and fever. He did not display any tissue loss or sensory changes. On physical exam, our patient's distal incision was warm and slightly indurated. His temperature was 38.5?C. Pedal pulses were 2+ in the left extremity and could not be palpated on the right.

Computed tomography angiography (CTA) of our patient (Figure 1) revealed a peri-graft fluid collection in the popliteal fossa of the right lower extremity and an occluded femoral-popliteal graft. Our patient's white blood cell count was 9000 cells with a 73% neutrophilia and his sedimentation rate was 64 Westergren units (mm/h). A CT-guided aspiration of the peri-graft fluid (Figure 2) was cultured and revealed E. cloacae with sensitivity to extended-spectrum cephalosporins, including cefepime, cefpirome, and cefclidine. At that time, our patient was started on a third generation cephalosporin, 1g intravenous ceftazidime every eight hours.

Six hours later, the patient underwent removal of the graft. Endarterectomy with saphenous vein patch angioplasty was performed on the common femoral artery for severe atherosclerotic stenosis. Collaterals from the deep femoral artery were relied upon to perfuse the limb. Our patient completed a six-week course of ceftazidime, currently uses the limb without discomfort, and is without signs of infection.


Synthetic peripheral bypass vascular grafts carry a high morbidity [7]. The risk of complications is as high as 50% in some studies. These risks include hemorrhage, limb ischemia, amputation, revision, or infection [7,8]. Rates for peripheral lower extremity prosthetic graft infection are as high as 12% [7]. Risk factors for graft infection are similar to those for wound infection and include obesity, diabetes, cancer and other immunocompromised states, as well as the use of immunosuppressive therapies. Our patient had a history of lung cancer in remission, but was without other risk factors.

The most common pathogen in graft infection is Staphylococcus aureus, which is responsible for 35% of graft infections. Gram-negative rods account for another 20% of vascular graft infections. Other common organisms in these infections include coagulase negative Staphylococcus, Streptococcus milleri, Enterococcus faecium, Escherichia coli, Bacteroides fragilis, Candida albicans and Pseudomonus aeruginosa. Polymicrobial colonization is commonly seen in immunocompromised patients. Grafts that require groin incisions have the greatest risk for infection, possibly due to contamination by bowel flora at the time of implantation [9].

Nosocomial E. cloacae infections are not entirely uncommon. Their isolated occurrence among vascular prosthetic grafts is rare, however. There are accounts of E. cloacae infection of an aortobifemoral bypass prosthesis and reports of E. cloacae infection in other types of vascular grafts (including an aortic graft), but, to our knowledge, this is the first account of an E. cloacae infection in a femoral-popliteal ePTFE bypass graft [10,11]. ePTFE is a woven form of PTFE, the same polymer used in Teflon? (DuPont). Research demonstrates this material is particularly prone to infection and biofilm formation relative to autologous tissues [12].

From the clinical perspective, biofilms are a major problem, since these structures display greatly increased resistance to physical and chemical insults. Crucially, biofilms are resistant to antibiotic treatment, making them particularly difficult to eliminate from patients and contaminated surgical equipment [13]. Several case reports, as well as larger studies from Canada, France, Israel, Spain, Italy and the UK indicate that infections caused by extended spectrum Beta-lactamase (ESBL) Enterobacteriaceae is an emerging problem in outpatient settings [15]. Therefore, graft removal should always be considered.

Prosthetic vascular graft infections commonly occur without specific symptoms [14]. Some authors suggest surveillance in the absence of clinical symptoms with the use of indium scan to identify infection. Clinical symptoms arose in this patient before surveillance could be conducted. When signs and symptoms are present, diagnoses of graft infection is still difficult and must often rely on clinical basis alone as blood cultures are often negative [16]. Most authors suggest the use of CTA as the most appropriate study to identify infection when clinical suspicion is high [17]. Peri-graft fluid, ectopic air, abnormal tissue planes or soft tissue swelling, and pseudoaneurysm formation are all signs of graft infection on CT. Non-specific findings include fever, leukocytosis with left shift, and elevated inflammation markers (erythrocyte sedimentation rate, ESR; C-reactive protein, CRP). Absence of other signs of graft infection should prompt a thorough workup for other causes. CTA was used to identify the nidus of infection in our patient.

Management requires resection of the infected graft, arterial repair or bypass with autologous tissue, and long-term antibiotics [18]. Placement of a new prosthetic graft should be avoided in the presence of acute infection. Adjuvant techniques of endarterectomy or percutaneous revascularization may be helpful. The importance of standard hospital and operating room hygiene measures (disinfection of hands) must not be underestimated. These measures are paramount to the control and prevention of infection. When an isolated surgical case of E. cloacae occurs, clinicians should have a high index of suspicion for device contamination, consider testing for possible microbial reservoirs, and also consider documenting the case in the literature [14].


Currently, our patient experiences mild claudication, but no rest pain. He has no evidence of infection following the removal of his ePTFE graft, endarterectomy of the common femoral artery, saphenous vein patch, and intravenous ceftazidime. Additionally, there are no records of E. cloacae infection of any other patient at this hospital within a month of original graft placement. This makes widespread contamination of surgical equipment unlikely.


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.

Authors' contributions

VJ analyzed and interpreted the patient data regarding the vascular graft infection and was a major contributor in writing the manuscript. JS removed the graft, performed common femoral artery, and performed a saphenous vein patch of the common femoral artery. JS was also a major contributor in writing the manuscript. IM analyzed the patient's medical history and all patient labs and imaging studies, as well as contacting the patient for consent. IM was the major contributor to writing the manuscript. All authors read and approved the final manuscript.

Rodriguez Jornet A,Garcia Garcia M,Mariscal D,Fontanals D,Cortes P,Coll P,An outbreak of gram-negative bacteremia (GNB), especially enterobacter cloacae, in patients with long-term tunnelled haemodialysis cathetersNefrologiaYear: 200323433334314558333
Andersen BM,Sorlie D,Hotvedt R,Almdahl SM,Olafsen K,George R,Multiply beta-lactam resistant enterobacter cloacae infections linked to the environmental flora in a unit for cardiothoracic and vascular surgeryScand J Infect DisYear: 198921218119110.3109/003655489090399672727635
Hughes CF,Grant AF,Leckie BD,Baird DK,Cardioplegic solution: A contamination crisisJ Thorac Cardiovasc SurgYear: 19869122963023753734
Ayus JC,Sheikh-Hamad D,Silent infection in clotted hemodialysis access graftsJ Am Soc NephrolYear: 199897131413179644644
Brothers TE,Von Moll LK,Niederhuber JE,Roberts JA,Walker-Andrews S,Ensminger WD,Experience with subcutaneous infusion ports in three hundred patientsSurg Gynecol ObstetYear: 198816642953013127896
Buxton AE,Anderson RL,Klimek J,Quintiliani R,Failure of disposable domes to prevent septicemia acquired from contaminated pressure transducersChestYear: 197874550851310.1378/chest.74.5.508738087
FitzGerald SF,Kelly C,Humphreys H,Diagnosis and treatment of prosthetic aortic graft infections: Confusion and inconsistency in the absence of evidence or consensusJ Antimicrob ChemotherYear: 200556699699910.1093/jac/dki38216269550
Willwerth BM,Waldhausen JA,Infection of arterial prosthesesSurg Gynecol ObstetYear: 197413934464524277536
Rubin RH,Fischman AJ,Callahan RJ,Khaw BA,Keech F,Ahmad M,111In-labeled nonspecific immunoglobulin scanning in the detection of focal infectionN Engl J MedYear: 1989321149359402779615
Heyer KS,Modi P,Morasch MD,Matsumura JS,Kibbe MR,Pearce WH,Resnick SA,Eskandari MK,Secondary infections of thoracic and abdominal aortic endograftsJ Vasc Interv RadiolYear: 200920217317910.1016/j.jvir.2008.10.03219097807
Botella GF,G?mez LM,Gadea IL,Rubio FL,Cant? CC,Aortoenteric fistula secondary to aortobifemoral prosthesis infectionAnales de Medicina InternaYear: 200219524625012108001
Delorme JM,Guidoin R,Canizales S,Vascular access for hemodialysis: pathologic features of surgically excised Expanded Polytetrafluoroethylene graftsAnn Vasc SurgYear: 1992651752410.1007/BF020008231463665
Welch M,Mikkelsen H,Swatton JE,Smith D,Thomas GL,Glansdorp FG,Spring DR,Cell-cell communication in Gram-negative bacteriaMol BiosystYear: 20051319620210.1039/b505796p16880983
Chow JW,Yu VL,Shlaes DM,Epidemiologic perspectives on enterobacter for the infection control professionalAm J Infect ControlYear: 199422419520110.1016/0196-6553(94)90067-17985817
Johann D,Pitout D,Nordmann P,Laupland KB,Poirel L,Emergence of Enterobacteriaceae producing extended-spectrum ?-lactamases (ESBLs) in the communityJ Antimicrobial ChemotherapyYear: 2005561525910.1093/jac/dki166
Treiman GS,Copland S,Yellin AE,Lawrence PF,McNamara RM,Treiman RL,Wound infections involving infrainguinal autogenous vein grafts: A current evaluation of factors determining successful graft preservationJ Vasc SurgYear: 200133594895410.1067/mva.2001.11420911331833
Wolma FJ,Derrick JR,McCoy J,Management of infected arterial graftsAm J SurgYear: 1973126679880210.1016/S0002-9610(73)80074-14758802
Antonios VS,Noel AA,Steckelberg JM,Wilson WR,Mandrekar JN,Harmsen WS,Prosthetic vascular graft infection: A risk factor analysis using a case-control studyJ InfectYear: 2006531495510.1016/j.jinf.2005.10.00416310254


[Figure ID: F1]
Figure 1 

CT angiogram of a small seroma in the right popliteal fossa taken prior to seroma biopsy and removal of the femoral-popliteal ePTFE bypass graft. Arrows point to the location of the seroma.

[Figure ID: F2]
Figure 2 

CT image used in correlation with CT-guided drainage of the abscess created by graft infection. Cultures of aspirated material revealed colonies of E. cloacae. Arrows point to needle biopsy.

Article Categories:
  • Case report

Previous Document:  Early phase resolution of mucosal eosinophilic inflammation in allergic rhinitis.
Next Document:  Prescreening based on the presence of CT-scan abnormalities and biomarkers (KL-6 and SP-D) may reduc...