Life-threatening Escherichia coli cellulitis in
patients with haematological malignancies
S. Sunder,1,2E. Haguenoer,2,3D. Bouvet,2,3S. Lissandre,4A. Bree,5
D. Perrotin,2,6E. Helloin,5P. Lanotte,2,3C. Schouler5and A. Guillon2,6
Received 8 January 2012
Accepted 6 May 2012
1Service de Me ´decine Interne et Maladies Infectieuses, CHRU de Tours, France
2Universite ´ Franc ¸ois Rabelais de Tours, France
3Service de Bacte ´riologie–Virologie, CHRU de Tours, France
4Service d’He ´matologie et The ´rapie Cellulaire, CHRU de Tours, France
5INRA, UR 1282 Infectiologie Animale et Sante ´ Publique, Nouzilly, France
6Service de Re ´animation Me ´dicale, CHRU de Tours, France
Cellulitis due to Escherichia coli is rare and usually secondary to a cutaneous portal of entry. Skin
and soft tissue infections (SSTI) secondary to E. coli bacteraemia have been reported exclusively
in immunodeficient patients. Here, we report two cases of serious cellulitis secondary to E. coli
bacteraemia in patients with haematological malignancies. Both isolated strains belonged to
phylogenetic group B2 and harboured some of the main virulence factor genes commonly found
in extra-intestinal pathogenic E. coli (ExPEC), including neuC, iro and fimH. Cellulitis due to E.
coli seems to be linked to the immunocompromised status of patients rather than to a highly
virulent clone. Nevertheless, some of the virulence factors appear to be important because both
isolates belong to phylogenetic group B2. This aetiology should be considered in SSTI in patients
with haematological malignancies.
Cellulitis is an acute spreading infection of the skin,
extending more deeply than erysipelas to reach subcuta-
neous tissues. Although most cases of cellulitis are caused by
group A streptococci, a number of other micro-organisms
may be responsible for this disease, including other b-
haemolytic streptococci, Staphylococcus aureus, Haemophilus
influenzae in children, Capnocytophaga canimorsus, follow-
ing a dog or cat bite, and Pseudomonas aeruginosa (Stevens
et al., 2005). Cellulitis due to Escherichia coli is rare and less
documented. Uropathogenic E. coli and other strains that
cause extra-intestinal infections are grouped under the term
2000). Recently, a Slovenian team (Petkovsek et al., 2009)
studied thevirulencefactorprofileof E.coliisolatedfromskin
andsoft tissueinfections(SSTI).They foundthat these strains
exhibited a remarkable virulence potential, comparable to
thatof E.colistrains isolated from urinary tract infections and
cases of bacteraemia. However, in all cases, the portal of entry
was cutaneous (surgical wounds, foot ulcers, fistulae, trau-
matic wounds, etc.). No reported cases of cellulitis were
secondary to an E. coli bloodstream infection.
Here, we report two cases of cellulitis associated with
bacteraemia without pyomyositis caused by E. coli in
patients with haematological malignancies (multiple myel-
oma and chronic lymphoid leukaemia). In both cases, the
phenotypic and molecular characteristics of the isolates
A 71-year-old man was admitted tointensivecareunit(ICU)
in January 2010 for septic shock. He had a medical history of
multiple myeloma from 2008, which was treated with
dexamethasone (40 mg day21twice a week for 2 months)
for cytopenia, with a recent asymptomatic recurrence. The
patient reported 2 days of progressive fever with pain,
swelling and erythema of the upper right limb. He was
initially admitted in a secondary health care centre and
treated with a fluid loading of 3500 ml, continuous injection
of norepinephrine, 2 g of ceftriaxone, 280 mg of gentamicin
and 200 mg of ketoprofen. On admission to the ICU, the
upper right limb was erythematic, bullous and tender; there
signs were: Glasgow coma scale 10, blood pressure 76/28
mmHg with anuria, pulse 96 beats min21and a temperature
Abbreviations: ExPEC, extra-intestinal pathogenic E. coli; ICU, intensive
care unit; MLST, multilocus sequence typing; SSTI, skin and soft tissue
infections; ST, sequence type.
Journal of Medical Microbiology (2012), 61, 1324–1327
1324 042366G2012 SGM Printed in Great Britain
of 37.7 uC. Laboratory investigations revealed a white cell
countof 1.16109l21withneutropenia (0.76109l21),plate-
lets 186109l21, haemoglobin 5.8 g dl21, serum creatinine
198 mmol l21, procalcitonin 8.21 ng ml21and prothrombin
time was prolonged. Blood gas showed metabolic acidosis
with lactate 5.4 mmol l21. Antimicrobial therapy was
modified for imipenem (1 g every 8 h) and gentamicin.
Axial CT image of the right limb showed diffuse superficial
soft-tissue swelling; there was no evidence of local fluid
collection or abscess formation in the deep musculature, nor
subcutaneous air or bone destruction. A surgical exploration
of the upper right limb showed no extension of infection to
the fascia. Cellulitis without primary superficial skin lesion
was diagnosed. The patient died on the same day. E. coli was
isolated from a skin biopsy culture without any other aerobic
or anaerobic bacteria. Moreover, only one blood culture was
(aminopenicillins, carboxypenicillins, cephalosporins and
penems), aminoglycosides and quinolones. The isolates were
only resistant to co-trimoxazole. The molecular analysis was
only performed on the isolate from skin biopsy. Unfor-
tunately, the isolate from blood was not preserved because
the positive blood culture was performed in another hospital
before the admission of the patient in the ICU.
A 53-year-old man was hospitalized in November 2009
following 3 days of fever with cutaneous eruption, ten days
after receiving chemotherapy (rituximab+dexamethaso-
ne+endoxan) for lymphoid leukaemia (stage C). The
patient received co-trimoxazole as a prophylaxis (400/
80 mg daily). On admission, his temperature was 39.2 uC,
blood pressure 86/58 mmHg and pulse 108 beats min21.
He had three erythematic skin lesions: on his left shoulder,
left thigh and left ankle. There was no arthritis (the joints
were painless, non-inflammatory and motilities were
preserved). There was no intravascular device. Laboratory
investigations found a white blood cell count of 1.16109
l21with neutropenia of 0.046109l21, platelets 586109
l21, haemoglobin 8.5 g dl21, serum creatinine 86 mmol l21,
and C-reactive protein 275 mg l21. Blood pressure was
rapidly normalized after loading of 1000 ml of physio-
logical serum. He was treated intravenously with ceftriax-
one (1 g daily) and amikacin (1200 mg) in the emergency
department and was transferred to the haematology
department. Twenty-four hours after admission, vanco-
mycin (2 g daily) was introduced and an injection of
granulocyte colony-stimulating factor (G-CSF) was given.
E. coli was isolated from two different blood cultures with a
time-to-positivity under 16 h. Among the b-lactams tested,
the strain was resistant to aminopenicillins and carboxy-
penicillins and susceptible to cephalosporins and penems.
It was also susceptible to aminoglycosides and quinolones
and was resistant to co-trimoxazole. Urine was sterile.
Cutaneous echography revealed no abscess. A skin biopsy
was performed. Aerobic and anaerobic cultures remained
sterile after 5 days of incubation. Histology confirmed the
diagnosis of cellulitis without evidence of bacteria or
mycelium. Colonoscopy did not reveal any digestive injury.
Due to the positivity of the blood culture, antimicrobial
therapy was changed to a combination of ciprofloxacin and
amoxicillin–clavulanic acid. The outcome was favourable
with regression of aplasia.
Blood cultures in both aerobic and anaerobic conditions
were performed with the BACTEC blood culture system
(Becton Dickinson). Cultures of skin biopsies were per-
formed in Schaedler broth with vitamin K3 (Oxoid) and on
various agar plates (trypticase soy agar supplemented with
5% horse blood, 5% blood Columbia agar and chocolate
agar plus PolyViteX (Oxoid)), incubated in different
atmospheres (aerobic, anaerobic and atmosphere with 5%
CO2, respectively) for 5 days. Antimicrobial susceptibility
was determined by the agar diffusion method performed on
Mueller–Hinton for blood culture isolates or by the Vitek
system (bioMe ´rieux) for skin biopsy samples. Susceptibility
test results were interpreted according to the French
guidelines of the Antibiogram Committee of the French
Society of Microbiology (CA-SFM, 2010).
Following the consent of the patients or their family, the two
strains of E. coli were deposited at the Biological Resource
Centre of INRA (Institut National de la Recherche Agro-
nomique, France) under accession numbers CIRM-BP-494
(skin biopsy isolate from patient 1) and CIRM-BP-495
(blood isolate from patient 2). The following analyses were
performed for each isolate: determination of the phylogen-
etic group, using a triplex PCR (Clermont et al., 2000);
determination of serotype by conventional serotyping; and
determination of the genotype by multilocus sequence
typing (MLST) (Wirth et al., 2006).
PCRs were performed to determine the presence of genes
encoding virulence factors representative of the main classes
of identified ExPEC virulence determinants, including
adhesins (papC, sfa/foc, afa, eae, fimH and its variant
fimAv), toxins (hlyA, cdt1, cdt2 and cnf1), iron capture
systems (iutA, iroN, iroB and iucD), invasin (ibeA) and
protectin (neuC), as well as a gene encoding an autotran-
sporter (tsh) (Johnson et al., 2001; Lefort et al., 2011).
Both isolates belonged to phylogenetic group B2. The results
of tests for virulence gene carriage are presented in Table 1.
Both isolates were positive for some classical ExPEC-
associated virulence genes. Both isolates possessed genes
codingforfimbriae (P fimbriae and/ortype1 fimbriae),iron
capture systems (Iro system and/or aerobactin) and the
capsular antigen K1. Only the isolate from patient 2
possessed the ibeA gene. Serotypes of isolates were O1
(patient 1) and O18 (patient 2). MLST showed two different
isolates, exhibiting two different combinations of alleles
among the seven sequenced loci, with no alleles in common.
These patterns correspond to sequence type (ST) ST357 for
patient 1 and to ST95 for patient 2.
Cellulitis due to Escherichia coli
Here, we report two cases of serious cellulitis caused by E.
coli in patients with haematological malignancies. SSTIs
caused by Gram-negative bacteria, notably E. coli, are not
common and present as primary skin infections with a
cutaneous portal of entry (Moet et al., 2007). Neither of
our patients had any cutaneous lesions. We supposed that
the skin infection was secondary to bloodstream infection
from a digestive source (translocation). Very few cases of
this have been described in the literature and the few
reported cases all occurred in immunocompromised patients
(Brzozowski & Ross, 1997; Kang et al., 2010; Sleiman et al.,
2007; Yoon et al., 1998).
Recently, E. coli seems to have emerged as a serious problem
among patients with haematological malignancies. In a
series of six cases of E. coli pyomyositis, three patients
required transfer to intensive care and two patients died.
Molecular analysis revealed that five of the six isolates
originated from the same E. coli lineage (ST131, phylogen-
etic group B2) (Vigil et al., 2010). The ST of the two clinical
cases reported here were different (ST357 and ST95).
Clinical presentationwaslocallylesssevere: cellulitiswithout
pyomyositis, one with a single location and the other with
multiple locations. Nevertheless, the prognosis seems to be
poor, with the death of one of the two patients. Non-
neutropenic patients may also be affected; in fact, patient 1
was only treated with corticotherapy. Consequently, among
patients with haematological malignancies, E. coli SSTI
secondary to blood diffusion appears as a polymorphous
syndrome with poor prognosis. While immunosuppression
is likely to play a role in disease outcome, bacterial virulence
may also have an impact on the pathogenesis.
Both E. coli strains belonged to phylogenetic group B2,
which was the main group found in a prospective study
aimed at characterizing the risk factors for E. coli bac-
teraemia (Lefort et al., 2011). E. coli of the B2 group usually
carry more of virulence-associated genes than those of other
phylogenetic groups (Johnson et al., 2002). The two isolates
were of serogroups O1:K1 (patient 1) and O18:K1 (patient
2). Isolates belonging to these serogroups are frequently
identified in urinary tract infections, bacteraemia and
neonatal meningitis (Ananias & Yano, 2008; Blanco et al.,
1996; Croxen & Finlay, 2010). MLST showed that neither
strain had any lineage. Up to now, only 12 strains have been
recorded as ST357 in the MLST database at the Environ-
mlst.ucc.ie/mlst/dbs/Ecoli/GetTableInfo_html). All are of
human origin, except one, which is of avian origin. Half of
them are known to be pathogenic and were isolated from
urinary tract infections or bacteraemia. Eleven of these
ST357 strains belonged to serological group K1. ST95 has
been more frequently observed, with 144 recorded strains, of
which 75% were of human origin. Fifty-six per cent of the
human pathogens from this ST are known to be pathogenic;
52% of them were isolated from urinary infections, 29%
from meningitis cases (mainly neonatal meningitis) and
16.5% from bacteraemia. ST95 complex has been reported
Table 1. Characteristics of studied Escherichia coli isolates
papC, P fimbriae; sfa/foc, S and F1C fimbriae; afa, afimbrial adhesion; eae, intimin adherence protein; fimH, type 1 fimbriae; fimAv, type 1 fimbriae avian pathogenic variant; iutA, receptor of the
ferric aerobactin; iroB/iroN, siderophore systems; iucD, aerobactin; ibeA, invasion of brain endothelium A; neuC, K1 capsule; hlyA, haemolysin; cnf1, cytotoxic necrotizing factor 1; cdt1/cdt2,
cytolethal distending toxin; tsh, autotransporter.
Iron capture systems
*Sequence type determined by MLST.
S. Sunder and others
1326 Journal of Medical Microbiology 61
to contain most of the related bacteria of serogroup O1, O2 Download full-text
and O18 which express the K1 polysaccharide (Mora et al.,
2009; Wirth et al., 2006).
Molecular analysis revealed that both strains harboured
virulence-factor genes commonly found in ExPEC. Both
isolates possessed neuC. E. coli isolated from patient 1
possessed the ibeA gene, encoding IbeA invasine, which is
involved in crossing the blood–brain barrier. Because of the
limited number of strains studied, we are not able to
determine whether these virulence-factor genes play a
direct role in the pathogenesis of E. coli SSTI.
In summary, cellulitis due to E. coli seems to be attributed
to the immunocompromised status of patients, induced by
haematological malignancy and worsened by the immu-
nosuppressive treatments, rather than to a highly virulent
strain, although the role of some virulence factors remains
to be determined.
In contrast to the E. coli pyomyositis cases reported by Vigil
et al. (2010), the isolates in our cases did not belong to the
virulent and multidrug-resistant E. coli lineage ST131,
which has been identified as an emerging cause of
fluoroquinolone-resistant and ESBL-positive extra-intest-
inal E. coli infection worldwide. Thus, the emergence of E.
coli SSTIs cannot be explained by the dissemination of this
clone alone, and other E. coli lineages may be involved.
Because of their potential for morbidity, Enterobacteriaceae,
notably E. coli, should be considered in cases of cellulitis in
patients with haematological malignancies. These patients
frequently use the health system and asantimicrobial therapy
is common in the field of haematology, initial antibacterial
treatment could consist of broad-spectrum b-lactams.
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