- Email: [email protected]
Is the treatment of Enterobius vermicularis co-infection necessary to eradicate Dientamoeba fragilis infection?
Accepted Manuscript Title: Is the treatment of Enterobius vermicularis coinfection necessary to eradicate Dientamoeba fragilis infection? Author: Jos´e A. Boga Susana Rojo Jonathan Fern´andez Mercedes Rodr´ıguez Carmen Iglesias Pablo Mart´ınez-Camblor Fernando V´azquez Azucena Rodr´ıguez-Guardado PII: DOI: Reference:
S1201-9712(16)31070-0 http://dx.doi.org/doi:10.1016/j.ijid.2016.05.027 IJID 2632
To appear in:
International Journal of Infectious Diseases
Received date: Revised date: Accepted date:
28-2-2016 24-5-2016 27-5-2016
Please cite this article as: Boga JA, Rojo S, Fern´andez J, Rodr´ıguez M, Iglesias C, Mart´ınez-Camblor P, V´azquez F, Rodr´ıguez-Guardado A, Is the treatment of Enterobius vermicularis coinfection necessary to eradicate Dientamoeba fragilis infection?, International Journal of Infectious Diseases (2016), http://dx.doi.org/10.1016/j.ijid.2016.05.027 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
1 2 3
Highlights
4
Treatment failure was significantly more frequent in patients with E. vermicularis coinfection (6 vs.
5
0, p=0.022, OR 2.263 [1.617-3.167]) and in those with a children in the family (0 vs. 6, p=0.080,
6
OR 1.654 [1.299-2.106]).
Metronidazole had a cure rate of 87.8%.
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M
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7 8
1 Page 1 of 9
8
Is the treatment of Enterobius vermicularis coinfection necessary to eradicate Dientamoeba
9
fragilis infection?
10
José A. Boga, Susana Rojo. Jonathan Fernández, Mercedes Rodríguez, Carmen Iglesias, Pablo Martínez-Camblor,
11
Fernando Vázquez, Azucena Rodríguez-Guardado.
12 José A. Boga. Servicio de Microbiología. Hospital Universitario Central de Asturias. Oviedo, Spain
14
Susana Rojo. Servicio de Microbiología. Hospital Universitario Central de Asturias. Oviedo, Spain
15
Jonathan Fernández. Servicio de Microbiología. Hospital Universitario Central de Asturias. Oviedo, Spain
16
Mercedes Rodríguez. Servicio de Microbiología. Hospital Universitario Central de Asturias. Oviedo, Spain
17
Carmen Iglesias. Servicio de Microbiología. Hospital Universitario Central de Asturias. Oviedo, Spain
18
Pablo Martínez-Camblor. Oficina de Investigación Biosanitaria (OIB) de Asturias. Oviedo, Spain and Universidad
19
Autónoma de Chile. Santiago, Chile.
20
Fernando Vázquez. Servicio de Microbiología. Hospital Universitario Central de Asturias. Oviedo, Spain
21
Azucena Rodríguez-Guardado. Unidad de Medicina Tropical, Hospital Universitario Central de Asturias. Oviedo,
22
Spain
24
Running title: Treatment of E. vermicularis and D. fragilis infection.
ed
23
M
an
us
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ip t
13
26 27
Corresponding author:
pt
25
Azucena Rodríguez-Guardado
29
Tropical Medicine Unit.
30
Hospital Universitario Central de Asturias.
31
Avenida Roma s/n 33011, Oviedo. Spain
32
E-mail: [email protected]
33
Phone: +34985108000 (39177)
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34 35 36 37 38 39
2 Page 2 of 9
39
Abstract Objectives
41
Dientamoeba fragilis is a pathogenic protozoan of the human gastrointestinal tract with a
42
worldwide distribution, which has emerged as an important and misdiagnosed cause of chronic
43
gastrointestinal illnesses such as diarrhea and "irritable-bowel-like" gastrointestinal disease. Very
44
little research has been conducted on the use of suitable antimicrobial compounds. Furthermore,
45
higher rates of coinfection with Enterobius vermicularis have been described suggesting that E.
46
vermicularis could influence the treatment of D. fragilis-infected patients. To study this, we have
47
evaluated the treatment of E. vermicularis- and D. fragilis-coinfected patients.
48
Design
49
Forty-nine patients with Dientamoeba fragilis infection, including 25 (51.0%) patients co-infected
50
with Enterobius vermicularis, were studied. All of them were treated with metronidazole. Patients
51
with E. vermicularis coinfection and/or an E. vermicularis-positive case in the family were treated
52
with mebendazole.
53
Results
54
Metronidazole treatment failure was significantly more frequent in patients with E. vermicularis
55
coinfection and in patients with children in the family.
56
Conclusions
57
Coinfection with E. vermicularis may act as a factor favoring D. fragilis infection by preventing
58
eradication measures and suggest that both parasites may be treated simultaneously.
Ac ce
pt
ed
M
an
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40
59 60
Keywords: Dientamoeba fragilis; treatment; metronidazole; Enterobius vermicularis; parasites
61
infection.
62 63 64 3 Page 3 of 9
64 Dientamoeba fragilis is a pathogenic protozoan of the human gastrointestinal tract with a
66
worldwide distribution. It has emerged as an important and misdiagnosed cause of chronic
67
gastrointestinal illnesses such as diarrhea and "irritable-bowel-like" gastrointestinal disease.1,2
68
Higher rates of coinfection with Enterobius vermicularis have been described in previous papers3,4.
69
Despite the growing importance of this parasite, very little research has been conducted on the use
70
of suitable antimicrobial compounds. Recently, a randomized research to evaluate the efficacy of
71
metronidazole in children with negative conclusions has been performed5. In this paper, the
72
influence of E. vermicularis and its treatment in the usefulness of metronidazole is evaluated.
73
A standard protocol for screening of imported diseases is routinely used in all of the individuals, which are
74
attended by our unit for the first time, regardless of race, sex, origin and symptomatology. All of those
75
individuals, who were infected by D. fragilis between January 2012 and January 2014, as well as
76
theirs infected households contacts were enrolled in this retrospective, descriptive study. This
77
research is part of an overall project entitled "Usefulness of molecular diagnosis techniques in
78
Parasitology" validated and approved by the Ethical Committee of Clinical Investigation of Asturias
79
(Spain).
80
A clinical history, including diarrhea within the preceding three months, nature of the diarrhea,
81
abdominal pain, intensity of fever, nausea and/or vomiting, urticaria, anal pruritus, anorexia and
82
weight loss, was collected. Diarrhea was defined as at least three unformed or liquid stools per day
83
for at least three days. Treatment history included antiparasitological drugs, as well.
84
Blood tests and biochemical analysis, including liver enzyme level, were performed in all patients.
85
Eosinophilia was defined as >500 eosinophils/mm3.
86
Three stool samples per patient were concentrated by using Copropack Extraction Kit C100
87
(Cromakit, Spain) according to manufacturer’s instructions then, stained with lugol and screened
88
under light microscope with a low magnification to detect helminth eggs, protozoa trophozoites and
89
cysts. An immunofluorescence test (MERIFLUOR® Cryptosporidium/Giardia kit, Meridian
Ac ce
pt
ed
M
an
us
cr
ip t
65
4 Page 4 of 9
Bioscience, USA) was performed using concentrated stool samples to detect Cryptosporidium spp
91
and Giardia lamblia. Genome detection of D. fragilis as well as Entamoeba histolytica and dispar
92
were detected in stool samples, previously extracted by using QIAmp DNA stool Mini kit (Qiagen,
93
Netherland), with two methods based on polymerase chain reaction (PCR) previously described6,7.
94
A pinworm test was performed in stool samples of all patients with D. fragilis. Thus, pinworm eggs
95
or a few adult worms, which were adhered to a piece of transparent cellophane tape applied to the
96
anal region on 2 consecutive mornings right after the infected person woke up and before any bowel
97
movement or cleansing (bath or shower), were identified by examination under a microscope.
98
Parasitological controls were performed four and eight weeks after the end of the treatment in all
99
patients. Patients who failed to deliver one or more pieces of cellophane tape or stool samples or
100
had received anti-parasitic treatment in the previous six months or were infected by other parasites
101
different to E. vermicularis were excluded.
102
All patients were treated with metronidazole 500 mg/8 hours (25-35 mg/kg/day in three doses in
103
children). Patients with E. vermicularis coinfection and/or an E. vermicularis-positive case in the
104
family were treated with mebendazole 100 mg/12 hours during three days.
105
Qualitative variables were compared using the χ2 test, the Fisher exact test, when necessary. For
106
quantitative variables, the Student t test for non paired variables or the Mann-Whitney U test were
107
used. Significance was designated at p<0.05. Multivariate analysis was performed using logistic
108
regression (enter method) to identify variables that showed an independent association with the
109
treatment failure. The variables included in the model are those with statistically significant
110
association (p <0.05) in the bivariate analysis. All tests were performed with the SPSS 15 software
111
for Windows (SPSS Inc., Chicago, IL, USA).
112
Forty-nine patients were studied and treated. Fifty-three percent of them were male. The mean age
113
was 30 years (range 3-71). Eighteen patients were less than fourteen years old. Most of them came
114
from Spain (65.3%), followed by Equatorial Guinea (12.2%), Pakistan (10.2%), Colombia (8.2%),
115
and Paraguay (4.1%). In immigrant patients, the average time of permanence in Spain prior the first
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pt
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M
an
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5 Page 5 of 9
consultation was 853 [±540] days and no patients had travelled to their country of origin in the last
117
year. Twenty-nine patients (59.2%) were asymptomatic. As for the remaining patients, the most
118
frequent symptoms were abdominal pain (10 patients) and diarrhea (3 patients). Only one patient
119
described anal pruritus. Twenty-seven patients (55%) had hypereosinophilia in blood, 17 of them
120
were asymptomatic. The mean of eosinophilia was 1361 [±1676] cells/mm3. Twenty-five (51%)
121
patients had a co-infection with E. vermicularis, 64% of them were children under 14 years.
122
All of them were treated with metronidazole with a cure rate of 87.8%. Thus, forty-three patients
123
had complete resolution of symptoms and a normalization of eosinophils levels. Nevertheless, six
124
patients showed a persistence of D. fragilis in control stool samples taken four weeks after the
125
treatment. No differences in sex or age between the cured and uncured patients were found. No
126
significant differences were found after studying whether the age under 14 years was associated
127
with treatment failure (3 vs. 3, p=0.656). Treatment failure was significantly more frequent in
128
patients with E. vermicularis coinfection (6 vs. 0, p=0.013, OR 1.316 [1.056-1.454]) and in those
129
with a children in the family (6 vs. 0, p=0.065, OR 1.231 [1.042-1.454]). All patients with treatment
130
failure were asymptomatic (Table 1).
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Table 1. Characteristics of cured and uncured patients. Parameter
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Demographic Characteristics Sex (M/F) Age Age under 14 years Children under 14 in family (yes/no) E. vermicularis detection Coinfected by E. vermicularis (yes/no) Relative with E. vermicularis (yes/no) Asymptomatic (Yes/No)
Cured N=43
Uncured N= 6
22/21 30[21] 15/28 26/17 19/24 27/16 23/20
P value
OR
4/2 27[17] 3/3 6/0
0.395 0.421 0.656 0.065
NS NS NS 1.231[1.042-1.454]
6/0 6/0 6/0
0.013 0.079 0.034
1.316[1.056-33.29] 1.222[1.041-1.435] 1.261[1.047-1.518]
133
A second treatment with paromomycin (25–35 mg/kg/day, usually divided in three doses for 5–10
134
days) was administered to the six patients with no response to metronidazole. A parasitological
135
control test was performed in all of these patients with negative results at four and eight weeks after
136
the end of the treatment indicating that all of them had responded to it. 6 Page 6 of 9
Dientamoeba fragilis is a trichomonad parasite, which has been described as a cause of
138
gastrointestinal disease. Although several reports support the efficacy of metronidazole for the
139
treatment of D. fragilis infection, others researches report treatment failures and relapses. Preiss et
140
al. (1991) administered metronidazole (30 mg/kg/day for 10 days) to children, resulting to be
141
effective in 70% of the cases. The remaining 30% of the cases required up to three follow-up
142
treatments for complete resolution of parasites and symptoms8. Vandenberg et al. (2006) reported a
143
parasitological and clinical cure in 8 out of 12 patients, although no dosage information was given9.
144
Although Stark et al. (2010) reported a similar cure rate to that found by us (80% of cases), a
145
relatively high rate of treatment failures/relapses (21.4%) was associated with the use of
146
metronidazole. The majority of treatment failures was associated with a three-day course of
147
metronidazole and was less likely with a longer duration of therapy1.
148
A recently randomized research with children showed that although eradication of D. fragilis was
149
significantly greater in a group of metronidazole-treated infected-patients than in a group of
150
placebo-treated infected-patients, it declined rapidly from 2 weeks to 8 weeks after the end of
151
treatment (62.5% and 24.9%, respectively). These data do not support the routine use of
152
metronidazole in the treatment of D. fragilis positive children with chronic gastrointestinal
153
symptoms5. In this research, a pinworm prevalence of 24% and a relative risk [1.20 (95% CI, 1.01,
154
1.44)] for post-treatment of D. fragilis infection when being pinworm positive were reported.
155
Higher pinworm prevalence (51%) and a similar relative risk were observed in our study, where all
156
patients with E. vermicularis infection were treated with mebendazole and the parasite was
157
eradicated at four and eight weeks after the end of treatment.
158
E. vermicularis has been associated to transmission of D. fragilis due to the higher rates of
159
coinfection described in several researches as well as the isolation of D. fragilis DNA in the surface
160
of E. vermicularis eggs3,4. Our results support the hypothesis that coinfection with E. vermicularis
161
may act as a factor favoring D. fragilis infection by preventing eradication measures and suggest
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7 Page 7 of 9
that both parasites may be treated simultaneously. The fact that E.vermicularis is a common parasite
163
in child population support that treatment failures is more common in this age group.
164
Further research would be necessary to evaluate the role of the association of D. fragilis and E.
165
vermicularis when choosing a treatment and if the use of mebendazole improves the treatment of D.
166
fragilis infection.
167
Conflict of interest statement
168
All authors state that there is no financial and personal relationships with other people or
169
organisations that could inappropriately influence (bias) their work. This study has not been funded
170
by any source. This work has been approved by the Ethical Committee of the Hospital Universitario
171
Central
us
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Asturias
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172 173
References
174
1. Stark D, Barratt J, Roberts T, Marriott D, Harkness J, Ellis J. A review of the clinical
175
presentation of dientamoebiasis. Am. J Trop Med Hyg 2010;82:614-9. 2. Gray TJ, Kwan YL, Phan T, Robertson G, Cheong EY, Gottlieb T. Dientamoeba fragilis: a
177
family cluster of disease associated with marked peripheral eosinophilia. Clin Infect Dis
178
2013;57:845-8.
180 181
cr
3. Girginkardeşler N, Kurt O, Kilimcioğlu AA, Ok UZ. Transmission of Dientamoeba fragilis: evaluation of the role of Enterobius vermicularis. Parasitol Int 2008;57:72-5. 4.
182
Ögren J, Dienus O, Löfgren S, Iveroth P, Matussek A. Dientamoeba fragilis DNA
us
179
ip t
176
detection in Enterobius vermicularis eggs. Pathog Dis 2013;69:157-8.
5. Röser D, Simonsen J, Stensvold CR, Olsen KE, Bytzer P, Nielsen HV et al. Metronidazole
184
therapy for treating dientamoebiasis in children is not associated with better clinical outcomes: a
185
randomized, double-blinded and placebo-controlled clinical trial. Clin Infect Dis 2014;58:1692-
186
9.
M
6.
Khairnar K, Parija SCA novel nested multiplex polymerase chain reaction (PCR) assay for
ed
187
an
183
differential detection of Entamoeba histolytica, E. moshkovskii and E. dispar DNA in stool
189
samples. BMC Microbiol 2007;7:47.
7. Stark D, Beebe N, Marriott D, Ellis J, Harkness J. Detection of Dientamoeba fragilis in fresh
191 192
stool specimens using PCR. Int J Parasitol 2005;35:57-62. 8. Preiss U, Ockert G, Broemme S, Otto A. On the clinical importance of Dientamoeba fragilis infections in childhood. J Hyg Epidemiol Microbiol Immunol 1991;35:27-34.
193 194
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190
pt
188
9.
Vandenberg O, Peek R, Souayah H, Dediste A, Buset M, Scheen R, et al. Clinical and
195
microbiological features of dientamoebiasis in patients suspected of suffering from a parasitic
196
gastrointestinal illness: a comparison of Dientamoeba fragilis and Giardia lamblia infections. Int
197
J Infect Dis 2006;10:255-61.
9 Page 9 of 9
S1201-9712(16)31070-0 http://dx.doi.org/doi:10.1016/j.ijid.2016.05.027 IJID 2632
To appear in:
International Journal of Infectious Diseases
Received date: Revised date: Accepted date:
28-2-2016 24-5-2016 27-5-2016
Please cite this article as: Boga JA, Rojo S, Fern´andez J, Rodr´ıguez M, Iglesias C, Mart´ınez-Camblor P, V´azquez F, Rodr´ıguez-Guardado A, Is the treatment of Enterobius vermicularis coinfection necessary to eradicate Dientamoeba fragilis infection?, International Journal of Infectious Diseases (2016), http://dx.doi.org/10.1016/j.ijid.2016.05.027 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
1 2 3
Highlights
4
Treatment failure was significantly more frequent in patients with E. vermicularis coinfection (6 vs.
5
0, p=0.022, OR 2.263 [1.617-3.167]) and in those with a children in the family (0 vs. 6, p=0.080,
6
OR 1.654 [1.299-2.106]).
Metronidazole had a cure rate of 87.8%.
Ac ce
pt
ed
M
an
us
cr
ip t
7 8
1 Page 1 of 9
8
Is the treatment of Enterobius vermicularis coinfection necessary to eradicate Dientamoeba
9
fragilis infection?
10
José A. Boga, Susana Rojo. Jonathan Fernández, Mercedes Rodríguez, Carmen Iglesias, Pablo Martínez-Camblor,
11
Fernando Vázquez, Azucena Rodríguez-Guardado.
12 José A. Boga. Servicio de Microbiología. Hospital Universitario Central de Asturias. Oviedo, Spain
14
Susana Rojo. Servicio de Microbiología. Hospital Universitario Central de Asturias. Oviedo, Spain
15
Jonathan Fernández. Servicio de Microbiología. Hospital Universitario Central de Asturias. Oviedo, Spain
16
Mercedes Rodríguez. Servicio de Microbiología. Hospital Universitario Central de Asturias. Oviedo, Spain
17
Carmen Iglesias. Servicio de Microbiología. Hospital Universitario Central de Asturias. Oviedo, Spain
18
Pablo Martínez-Camblor. Oficina de Investigación Biosanitaria (OIB) de Asturias. Oviedo, Spain and Universidad
19
Autónoma de Chile. Santiago, Chile.
20
Fernando Vázquez. Servicio de Microbiología. Hospital Universitario Central de Asturias. Oviedo, Spain
21
Azucena Rodríguez-Guardado. Unidad de Medicina Tropical, Hospital Universitario Central de Asturias. Oviedo,
22
Spain
24
Running title: Treatment of E. vermicularis and D. fragilis infection.
ed
23
M
an
us
cr
ip t
13
26 27
Corresponding author:
pt
25
Azucena Rodríguez-Guardado
29
Tropical Medicine Unit.
30
Hospital Universitario Central de Asturias.
31
Avenida Roma s/n 33011, Oviedo. Spain
32
E-mail: [email protected]
33
Phone: +34985108000 (39177)
Ac ce
28
34 35 36 37 38 39
2 Page 2 of 9
39
Abstract Objectives
41
Dientamoeba fragilis is a pathogenic protozoan of the human gastrointestinal tract with a
42
worldwide distribution, which has emerged as an important and misdiagnosed cause of chronic
43
gastrointestinal illnesses such as diarrhea and "irritable-bowel-like" gastrointestinal disease. Very
44
little research has been conducted on the use of suitable antimicrobial compounds. Furthermore,
45
higher rates of coinfection with Enterobius vermicularis have been described suggesting that E.
46
vermicularis could influence the treatment of D. fragilis-infected patients. To study this, we have
47
evaluated the treatment of E. vermicularis- and D. fragilis-coinfected patients.
48
Design
49
Forty-nine patients with Dientamoeba fragilis infection, including 25 (51.0%) patients co-infected
50
with Enterobius vermicularis, were studied. All of them were treated with metronidazole. Patients
51
with E. vermicularis coinfection and/or an E. vermicularis-positive case in the family were treated
52
with mebendazole.
53
Results
54
Metronidazole treatment failure was significantly more frequent in patients with E. vermicularis
55
coinfection and in patients with children in the family.
56
Conclusions
57
Coinfection with E. vermicularis may act as a factor favoring D. fragilis infection by preventing
58
eradication measures and suggest that both parasites may be treated simultaneously.
Ac ce
pt
ed
M
an
us
cr
ip t
40
59 60
Keywords: Dientamoeba fragilis; treatment; metronidazole; Enterobius vermicularis; parasites
61
infection.
62 63 64 3 Page 3 of 9
64 Dientamoeba fragilis is a pathogenic protozoan of the human gastrointestinal tract with a
66
worldwide distribution. It has emerged as an important and misdiagnosed cause of chronic
67
gastrointestinal illnesses such as diarrhea and "irritable-bowel-like" gastrointestinal disease.1,2
68
Higher rates of coinfection with Enterobius vermicularis have been described in previous papers3,4.
69
Despite the growing importance of this parasite, very little research has been conducted on the use
70
of suitable antimicrobial compounds. Recently, a randomized research to evaluate the efficacy of
71
metronidazole in children with negative conclusions has been performed5. In this paper, the
72
influence of E. vermicularis and its treatment in the usefulness of metronidazole is evaluated.
73
A standard protocol for screening of imported diseases is routinely used in all of the individuals, which are
74
attended by our unit for the first time, regardless of race, sex, origin and symptomatology. All of those
75
individuals, who were infected by D. fragilis between January 2012 and January 2014, as well as
76
theirs infected households contacts were enrolled in this retrospective, descriptive study. This
77
research is part of an overall project entitled "Usefulness of molecular diagnosis techniques in
78
Parasitology" validated and approved by the Ethical Committee of Clinical Investigation of Asturias
79
(Spain).
80
A clinical history, including diarrhea within the preceding three months, nature of the diarrhea,
81
abdominal pain, intensity of fever, nausea and/or vomiting, urticaria, anal pruritus, anorexia and
82
weight loss, was collected. Diarrhea was defined as at least three unformed or liquid stools per day
83
for at least three days. Treatment history included antiparasitological drugs, as well.
84
Blood tests and biochemical analysis, including liver enzyme level, were performed in all patients.
85
Eosinophilia was defined as >500 eosinophils/mm3.
86
Three stool samples per patient were concentrated by using Copropack Extraction Kit C100
87
(Cromakit, Spain) according to manufacturer’s instructions then, stained with lugol and screened
88
under light microscope with a low magnification to detect helminth eggs, protozoa trophozoites and
89
cysts. An immunofluorescence test (MERIFLUOR® Cryptosporidium/Giardia kit, Meridian
Ac ce
pt
ed
M
an
us
cr
ip t
65
4 Page 4 of 9
Bioscience, USA) was performed using concentrated stool samples to detect Cryptosporidium spp
91
and Giardia lamblia. Genome detection of D. fragilis as well as Entamoeba histolytica and dispar
92
were detected in stool samples, previously extracted by using QIAmp DNA stool Mini kit (Qiagen,
93
Netherland), with two methods based on polymerase chain reaction (PCR) previously described6,7.
94
A pinworm test was performed in stool samples of all patients with D. fragilis. Thus, pinworm eggs
95
or a few adult worms, which were adhered to a piece of transparent cellophane tape applied to the
96
anal region on 2 consecutive mornings right after the infected person woke up and before any bowel
97
movement or cleansing (bath or shower), were identified by examination under a microscope.
98
Parasitological controls were performed four and eight weeks after the end of the treatment in all
99
patients. Patients who failed to deliver one or more pieces of cellophane tape or stool samples or
100
had received anti-parasitic treatment in the previous six months or were infected by other parasites
101
different to E. vermicularis were excluded.
102
All patients were treated with metronidazole 500 mg/8 hours (25-35 mg/kg/day in three doses in
103
children). Patients with E. vermicularis coinfection and/or an E. vermicularis-positive case in the
104
family were treated with mebendazole 100 mg/12 hours during three days.
105
Qualitative variables were compared using the χ2 test, the Fisher exact test, when necessary. For
106
quantitative variables, the Student t test for non paired variables or the Mann-Whitney U test were
107
used. Significance was designated at p<0.05. Multivariate analysis was performed using logistic
108
regression (enter method) to identify variables that showed an independent association with the
109
treatment failure. The variables included in the model are those with statistically significant
110
association (p <0.05) in the bivariate analysis. All tests were performed with the SPSS 15 software
111
for Windows (SPSS Inc., Chicago, IL, USA).
112
Forty-nine patients were studied and treated. Fifty-three percent of them were male. The mean age
113
was 30 years (range 3-71). Eighteen patients were less than fourteen years old. Most of them came
114
from Spain (65.3%), followed by Equatorial Guinea (12.2%), Pakistan (10.2%), Colombia (8.2%),
115
and Paraguay (4.1%). In immigrant patients, the average time of permanence in Spain prior the first
Ac ce
pt
ed
M
an
us
cr
ip t
90
5 Page 5 of 9
consultation was 853 [±540] days and no patients had travelled to their country of origin in the last
117
year. Twenty-nine patients (59.2%) were asymptomatic. As for the remaining patients, the most
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frequent symptoms were abdominal pain (10 patients) and diarrhea (3 patients). Only one patient
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described anal pruritus. Twenty-seven patients (55%) had hypereosinophilia in blood, 17 of them
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were asymptomatic. The mean of eosinophilia was 1361 [±1676] cells/mm3. Twenty-five (51%)
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patients had a co-infection with E. vermicularis, 64% of them were children under 14 years.
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All of them were treated with metronidazole with a cure rate of 87.8%. Thus, forty-three patients
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had complete resolution of symptoms and a normalization of eosinophils levels. Nevertheless, six
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patients showed a persistence of D. fragilis in control stool samples taken four weeks after the
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treatment. No differences in sex or age between the cured and uncured patients were found. No
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significant differences were found after studying whether the age under 14 years was associated
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with treatment failure (3 vs. 3, p=0.656). Treatment failure was significantly more frequent in
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patients with E. vermicularis coinfection (6 vs. 0, p=0.013, OR 1.316 [1.056-1.454]) and in those
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with a children in the family (6 vs. 0, p=0.065, OR 1.231 [1.042-1.454]). All patients with treatment
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failure were asymptomatic (Table 1).
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Table 1. Characteristics of cured and uncured patients. Parameter
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Demographic Characteristics Sex (M/F) Age Age under 14 years Children under 14 in family (yes/no) E. vermicularis detection Coinfected by E. vermicularis (yes/no) Relative with E. vermicularis (yes/no) Asymptomatic (Yes/No)
Cured N=43
Uncured N= 6
22/21 30[21] 15/28 26/17 19/24 27/16 23/20
P value
OR
4/2 27[17] 3/3 6/0
0.395 0.421 0.656 0.065
NS NS NS 1.231[1.042-1.454]
6/0 6/0 6/0
0.013 0.079 0.034
1.316[1.056-33.29] 1.222[1.041-1.435] 1.261[1.047-1.518]
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A second treatment with paromomycin (25–35 mg/kg/day, usually divided in three doses for 5–10
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days) was administered to the six patients with no response to metronidazole. A parasitological
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control test was performed in all of these patients with negative results at four and eight weeks after
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the end of the treatment indicating that all of them had responded to it. 6 Page 6 of 9
Dientamoeba fragilis is a trichomonad parasite, which has been described as a cause of
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gastrointestinal disease. Although several reports support the efficacy of metronidazole for the
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treatment of D. fragilis infection, others researches report treatment failures and relapses. Preiss et
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al. (1991) administered metronidazole (30 mg/kg/day for 10 days) to children, resulting to be
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effective in 70% of the cases. The remaining 30% of the cases required up to three follow-up
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treatments for complete resolution of parasites and symptoms8. Vandenberg et al. (2006) reported a
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parasitological and clinical cure in 8 out of 12 patients, although no dosage information was given9.
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Although Stark et al. (2010) reported a similar cure rate to that found by us (80% of cases), a
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relatively high rate of treatment failures/relapses (21.4%) was associated with the use of
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metronidazole. The majority of treatment failures was associated with a three-day course of
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metronidazole and was less likely with a longer duration of therapy1.
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A recently randomized research with children showed that although eradication of D. fragilis was
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significantly greater in a group of metronidazole-treated infected-patients than in a group of
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placebo-treated infected-patients, it declined rapidly from 2 weeks to 8 weeks after the end of
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treatment (62.5% and 24.9%, respectively). These data do not support the routine use of
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metronidazole in the treatment of D. fragilis positive children with chronic gastrointestinal
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symptoms5. In this research, a pinworm prevalence of 24% and a relative risk [1.20 (95% CI, 1.01,
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1.44)] for post-treatment of D. fragilis infection when being pinworm positive were reported.
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Higher pinworm prevalence (51%) and a similar relative risk were observed in our study, where all
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patients with E. vermicularis infection were treated with mebendazole and the parasite was
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eradicated at four and eight weeks after the end of treatment.
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E. vermicularis has been associated to transmission of D. fragilis due to the higher rates of
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coinfection described in several researches as well as the isolation of D. fragilis DNA in the surface
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of E. vermicularis eggs3,4. Our results support the hypothesis that coinfection with E. vermicularis
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may act as a factor favoring D. fragilis infection by preventing eradication measures and suggest
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7 Page 7 of 9
that both parasites may be treated simultaneously. The fact that E.vermicularis is a common parasite
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in child population support that treatment failures is more common in this age group.
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Further research would be necessary to evaluate the role of the association of D. fragilis and E.
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vermicularis when choosing a treatment and if the use of mebendazole improves the treatment of D.
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fragilis infection.
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Conflict of interest statement
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All authors state that there is no financial and personal relationships with other people or
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organisations that could inappropriately influence (bias) their work. This study has not been funded
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by any source. This work has been approved by the Ethical Committee of the Hospital Universitario
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References
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1. Stark D, Barratt J, Roberts T, Marriott D, Harkness J, Ellis J. A review of the clinical
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presentation of dientamoebiasis. Am. J Trop Med Hyg 2010;82:614-9. 2. Gray TJ, Kwan YL, Phan T, Robertson G, Cheong EY, Gottlieb T. Dientamoeba fragilis: a
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family cluster of disease associated with marked peripheral eosinophilia. Clin Infect Dis
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2013;57:845-8.
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3. Girginkardeşler N, Kurt O, Kilimcioğlu AA, Ok UZ. Transmission of Dientamoeba fragilis: evaluation of the role of Enterobius vermicularis. Parasitol Int 2008;57:72-5. 4.
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Ögren J, Dienus O, Löfgren S, Iveroth P, Matussek A. Dientamoeba fragilis DNA
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