J Antimicrob Chemother 2011; 66: 2308 – 2311doi:10.1093/jac/dkr293 Advance Access publication 15 July 2011
Primary antibiotic resistance of Helicobacter pylori strains isolated
from Portuguese children: a prospective multicentre study
Mo´nica Oleastro 1*, Jose´ Cabral 2, Paulo Magalha˜es Ramalho 3,4, Piedade Sande Lemos 5, Eleonora Paixa˜o 6,
Joa˜o Benoliel 1, Andrea Santos 1 and Ana Isabel Lopes 3,4
1Departamento de Doenc¸as Infecciosas, Instituto Nacional Sau´de Dr Ricardo Jorge, Lisboa, Portugal; 2Unidade de GastrenterologiaInfantil, Centro Hospitalar Lisboa Central, Lisboa, Portugal; 3Unidade de Gastrenterologia Pedia´trica, Hospital Universita´rio de SantaMaria, Lisboa, Portugal; 4Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal; 5Unidade de Gastrenterologia Pedia´trica,
Hospital Fernando da Fonseca, Lisboa, Portugal; 6Departamento de Epidemiologia, Instituto Nacional Sau´de Dr Ricardo Jorge,
*Corresponding author. Tel: +351-217-508-179/217-519-231; Fax: +351-217-526-400; E-mail: [email protected]
Received 28 March 2011; returned 6 May 2011; revised 9 June 2011; accepted 21 June 2011
Objectives: The aim of this study was to prospectively assess the pattern of evolution of primary resistance toantibiotics in Helicobacter pylori strains isolated from Portuguese children over a 10 year period (2000– 09).
Methods: A total of 1115 H. pylori strains were tested for antibiotic susceptibility to clarithromycin, metronida-
zole, amoxicillin, ciprofloxacin and tetracycline.
Results: H. pylori strains were isolated from children and adolescents [ages 4 months –18 years (mean age10.17+4.03 years)], comprising 562 (50.4%) boys and 553 (49.6%) girls. Overall, the primary resistance ratewas 34.7% to clarithromycin, 13.9% to metronidazole and 4.6% to ciprofloxacin, while 6.9% were resistantto two of these antibiotics simultaneously. Resistance to amoxicillin and to tetracycline was not detected. Ingeneral, the resistance rate was not associated with gender or the children’s age. European ethnicity, whencompared with an African background, was associated with clarithromycin resistance [P ¼ 0.002; odds ratio(OR) ¼ 0.30; 95% confidence interval (CI) 0.14–0.66], while the inverse situation was observed for metronida-zole (P,0.001; OR ¼ 3.50; 95% CI 1.90– 6.45). No significant temporal trend was noticed for resistance to clar-ithromycin and metronidazole, whereas ciprofloxacin and double-resistance rates have significantly increasedover time (P ¼ 0.004 and P ¼ 0.05, respectively).
Conclusions: The primary resistance rate of H. pylori strains isolated from Portuguese children to the commonlyused anti-H. pylori antibiotics used is high. Additionally, the increasing trend of ciprofloxacin-resistant anddouble-resistant strains may compromise H. pylori eradication in a high-prevalence population.
Keywords: H. pylori, temporal trend, Portugal
The most common first-line regimen for the eradication of
H. pylori consists of a combination of clarithromycin or metroni-
Helicobacter pylori colonizes the human gastric mucosa of more
dazole, with amoxicillin, plus a proton pump inhibitor (PPI). Pro-
than 50% of the world’s population, with infection always elicit-
ing an acute immune response that fails, however, in achieving
fluoroquinolones, tetracyclines or rifamycin-based therapies.
spontaneous eradicaThe lifelong persistence of this infec-
Considering both the large percentage of the infected population
tion may result in the development of non-ulcer dyspepsia
and the high and increasing rates of antibiotic resistance
(NUD), which may further progress to severe gastric diseases,
reported worldwide, the issue of treatment is thus currently
such as peptic ulcer disease (PUD) and two forms of gastric
unsolved and particularly problematic.
cancer [adenocarcinoma and mucosa-associated lymphoid
The actual prevalence of H. pylori antibiotic resistance among
children in Portugal is not known. The present study aimed to
# The Author 2011. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved.
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Primary H. pylori resistance in Portuguese children
prospectively assess the pattern of evolution of primary resist-
ance to antibiotics in H. pylori strains isolated from Portuguese
Overall, the primary resistance rate of H. pylori was 34.7%
children over a 10 year period (2000– 09), as well as identify
(n¼ 387) to clarithromycin (median MIC 0.016 mg/L, range
0.016– 256), 13.9% (n¼ 155) to metronidazole (median MIC0.25 mg/L, range 0.016– 256) and 4.6% (n¼ 51) to ciprofloxacin.
Simultaneous resistance to two of these antibiotics occurred in6.9% (n¼ 76) of the isolates, of which 72.4% (n ¼55) were resist-
ant to both clarithromycin and metronidazole, 23.7% (n¼ 18) to
From January 2000 to December 2009, a total of 1115 H. pylori strains
both clarithromycin and ciprofloxacin, and 3.9% (n¼ 3) to metro-
were prospectively isolated from Portuguese children and adolescents
nidazole and ciprofloxacin. One strain was simultaneously resist-
attending the three Paediatric Gastroenterology Units in the Lisbon
ant to these three antibiotics. Resistance to amoxicillin (median
area for severe and/or recurrent upper gastrointestinal symptoms sug-
MIC 0.016 mg/L, range 0.016–0.5) and tetracycline was not
gestive of organic disease and considered sufficiently relevant to justify
an upper endoscopy and antibiotic treatment. Demographic and clinical
No overall significant trend for resistance to clarithromycin or
data were collected retrospectively. None of the patients had been
metronidazole was noticed. Indeed, considering three time
treated for H. pylori infection before endoscopy. Clinical strains were cul-
periods, 2000 –02 (n¼ 191), 2003 –05 (n¼ 320) and 2006–09
tured from a pool of colonies from antral biopsy specimens.
(n¼ 604), a stationary trend could be observed for both these
antibiotics (Table although between 2000 –02 and 2003 –
05, a significant decrease in the metronidazole resistance ratewas observed (P ¼0.037) (Table ). The clarithromycin and
Susceptibility testing was performed using Etest (bioMe´rieux, Marcy
metronidazole MIC values were also stable throughout the
l’E´toile, France) for clarithromycin, metronidazole and amoxicillin, and
time period studied (data not shown).
by disc diffusion (Oxoid, Hampshire, UK) for ciprofloxacin and tetracycline.
In contrast, the resistance rate to ciprofloxacin has been signifi-
The MIC breakpoints used were ≥1 mg/L for clarithromycin, .8 mg/L for
cantly rising over time, particularly during the period 2006 –09
metronidazole and .0.5 mg/L for amoxicillin, according to previous refer-
(P ¼ 0.004), and the same scenario has been observed for the
By disc diffusion, strains were classified as resistant if growth inhi-bition zones were ,20 mm for ciprofloxacin (5 mg) and ,17 mm for
double-resistant strains (P ¼ 0.050) (Figure ).
tetracycline (30 mg) [Comite´ de l’Antibiogramme de la Socie´te´ Franc¸aise
The univariate analysis showed that, overall, there was no
de Microbiologie, Recommendations 2010 (Edition de Janvier 2010),
association of resistance to clarithromycin, metronidazole or
ciprofloxacin with children’s gender or disease outcome(Table except that metronidazole resistance was morecommon in older children (group aged 11–18 years), particularly
when comparing with the youngest children (13.7% versus 9.9%,
Statistical analysis was performed with the statistical package PASW
respectively; P ¼0.051; OR ¼1.76; 95% CI 1.00 –3.10). Resistance
Statistics version 18.01 (IBM SPSS Statistics, release 18.0, July 2009).
to clarithromycin was associated with European ethnicity, when
Pearson’s x2 test and 95% confidence intervals (CIs) were used. Identifi-
compared with an African background (37.0% versus 15.1%,
cation of variables associated with H. pylori antibiotic resistance was per-
respectively; P ¼ 0.002; OR¼ 0.30; 95% CI 0.14– 0.66), while,
formed by univariate logistic regression and confirmed by multiple
inversely, resistance to metronidazole was more common
logistic regression analysis. The level of significance was set at 5%.
among African children (35.8% versus 13.8%, respectively;P,0.001; OR¼ 3.50; 95% CI 1.90–6.45). No significantly
related factors were related to ciprofloxacin and double resist-ance (Table ). All the associations found were confirmed by
multiple logistic regression analysis (data not shown).
Within a 10 year observation period, 1115 H. pylori strains were iso-lated from children and adolescents, ages 4 months –18 years
(mean age 10.17+4.03 years), comprising 562 (50.4%) boysand 553 (49.6%) girls. Children were stratified into three age
The present study, concerning primary resistance to antibiotics of
groups: 0 –5 years (163, 14.6%); 6 –10 years (430, 38.6%); and
H. pylori strains isolated between 2000 and 2009 from 1115
11 –18 years (522, 46.8%). Information on ethnicity was available
Portuguese children, shows that the overall resistance rate
for 615 (55.2%) children, with the following distribution: 554
remains high, in particular to clarithromycin (34.7%). These
(90.1%) European [mostly Portuguese (98%)], 53 (8.6%) African
data are corroborated by a recent European multicentre study
and 8 (1.3%) Asian or Caucasian/European. According to clinical
on antibiotic resistance of H. pylori strains showing that children
outcome, most of the children (96%, n¼ 1069) presented with
from south Europe presented a significant risk for primary clari-
NUD (comprising severe recurrent abdominal pain, reflux-like dys-
thromycin resistance, which is likely a consequence of a recog-
pepsia, vomiting, coeliac disease and unexplained refractory side-
nized overuse in the past and the persistent use nowadays of
ropenic anaemia) and 4.0% (n¼ 44) had PUD. This latter condition
macrolides for the treatment of upper respiratory tract infections
was significantly more common in older children [5.4% versus
in those In our study, the only factor associated with
2.8%; P ¼ 0.021; odds ratio (OR) ¼2.12; 95% CI 1.13 –3.99] and
clarithromycin resistance was European ethnicity, compared with
also in boys (63.6% versus 36.4%; P¼ 0.025; OR¼ 2.04; 95% CI
an African background, as shown in previous studies.– The high
H. pylori clarithromycin primary resistance recently reported in
Table 1. Univariate analysis of factors associated with H. pylori primary resistance to clarithromycin, metronidazole and ciprofloxacin amongpaediatric patients
aP value obtained by univariate logistic model.
Statistically significant P values (,0.05) are highlighted in bold.
Figure 1. Temporal trend for H. pylori resistance to ciprofloxacin and to two of the antibiotics simultaneously (clarithromycin, metronidazole orciprofloxacin), considering three time periods: 2000–02 (00–02, n ¼191), 2003–05 (03– 05, n¼320) and 2006–09 (06– 09, n¼604).
children from several European countries, as well as from other
The metronidazole primary resistant rate observed in our
parts of the developed world, emphasizes that this is a
study (13.9%) was about 2-fold lower than the average rate
reported for European childr– This discrepancy may be
Primary H. pylori resistance in Portuguese children
only partially explained by the lower percentage of children withAfrican ethnicity (8.6%) than that reported in other studies. This
result also contrasts with the high primary resistance seen
This work was partially supported by the BNP Paribas patronage.
among Portuguese adults (32.3%),and likely reflects differ-ences in metronidazole consumption according to the patient’sage. Indeed, the lack of a metronidazole paediatric formulation
in Portugal may discourage parents to treat their children, result-ing in less exposure to this antibiotic.
The high rate of metronidazole resistance detected in our
study among African children (35.8%) is in agreement withother reports and consistent with its extensive use for treating
parasitic diseases in tropical countries.Metronidazole resistance
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In conclusion, this is the first H. pylori antibiotic resistance
multicentre study ever conducted in Portugal, comprising a
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Summary of Assurances & Risks from Committee Meetings Name of Group: Date of meeting: Key issues arising: Board approval to roll out e-PRF to remainder of Trust; Manchester patient safety culture review; Community working through Know Your Blood Pressure campaign, to include funding from the British Heart Foundation; Senior manager from outside the Trust working 2 da
Antabus® 1. NOMBRE DEL MEDICAMENTO Forma de administración Antabus se administra por vía oral. Añadir los comprimidos prescritos en un vaso de agua o zumo de frutas hasta su completa disolución y beber inmediatamente. 2. COMPOSICIÓN CUALITATIVA Y CUANTITATIVA Preferiblemente, Antabus debe tomarse al levantarse, aunque en pacientes que presentan efectos sedante puede tomarse Cada