Data from the European Antimicrobial Resistance Surveillance System
(EARSS) [www.earss.rivm] indicate that the highest levels of antibiotic
resistance have been found within the Mediterranean countries participating
in the system. On the other hand, information about the prevalence
of antimicrobial resistance in the non-European countries of the southern
and eastern Mediterranean has, in the past, been sparse. Nevertheless,
high levels of resistance have been reported in Streptococcus pneumoniae [1,2], Staphylococcus
aureus  as well as within species of the Enterobacteriacae
[4,5]. Unfortunately, besides being few in number, these studies have
been totally unrelated, using different methodologies and, as a result,
are difficult to compare .
This deficiency has been addressed by the Antibiotic Resistance Surveillance & Control
in the Mediterranean Region (ARMed) project [www.slh.gov.mt/armed]
which began in January 2003,7 and is funded by the European Commission
under the INCOMED programme of the DG Research Fifth Framework Protocol
(ICA3-CT-2002-10015). Over its four year funding period, this study
is documenting the prevalence of antibiotic resistance in southern
and eastern Mediterranean countries, as well as attempting to investigate
potential factors such as antibiotic consumption and infection control.
We report on the midway findings of ARMed-EARSS, the resistance epidemiology
subcomponent of the project.
ARMed-EARSS collects susceptibility test results from invasive isolates
of Staphylococcus aureus, Streptococcus pneumoniae, Escherichia coli,
Enterococcus faecium and faecalis routinely isolated from clinical
samples of blood and cerebrospinal fluid in the participating laboratories
situated in Algeria, Cyprus, Egypt, Jordan, Lebanon, Malta, Morocco,
Tunisia and Turkey. These laboratories are asked to send information
only about the first isolate of each organism from each patient. ARMed-EARSS
uses almost identical protocols to those adopted and validated by the
EARSS project, enabling comparison between data from the two projects.
The laboratories follow their routine procedures and breakpoints, which
in 86.8% of the participants were based on CLSI (formerly NCCLS) guidelines.
S. aureus testing determines oxacillin susceptibility by
an oxacillin screen plate (6 mg/l) or alternatively, by an oxacillin
disk test (1 µg or 5 µg) and a cefoxitin disk. ARMed laboratories
screen invasive S. pneumoniae isolates for oxacillin resistance
which, when found to be non-susceptible, is confirmed and determined
to intermediate or high-level resistance to penicillin by determination
of minimum inhibitory concentration (MIC) using E-test (AB Biodisk,
Solna, Sweden). The protocol for E. coli susceptibility testing requires
disc diffusion testing, amongst others, of a fluoroquinolone (ciprofloxacin
and/or ofloxacin) and a third-generation cephalosporin (cefotaxime
or ceftriaxone and/or ceftazidime). E-test confirmation is requested
in cases of resistance to third generation cephalosporins in E. coli
and vancomycin in enterococci. ARMed-EARSS protocols are accessible
at the ARMed website (http://www.slh.gov.mt/armed/earss.asp).
The website also includes an interactive function where maps for specific
drug-bug combinations for any of the participating countries can be
generated, as specified by the user.
To assess the reliability and comparability of susceptibility test
results, two external quality assurance (EQA) exercises were performed
in September 2003 and 2004 by all ARMed participating laboratories.
These exercises were performed in collaboration with UK NEQAS (United
Kingdom National External Quality Assessment Service) and undertaken
concurrently with those run by EARSS for their laboratories.
A total of 5883 isolates were investigated, as reported in the first
21 months of the project by the 53 participating ARMed laboratories,
which in turn serve 60 hospitals. Of these, 3017 (51.3%) were S.
aureus, 1567 (26.6%) were E. coli, 745 (12.7%) were S.
pneumoniae, 390 (6.6%) were E. faecalis, and 164 (2.8%)
were E. faecium. Resistance to penicillin in isolates of S.
pneumoniae was reported from all the collaborating countries except
for Malta and Cyprus (Fig. 1). When only data from countries reporting
at least 10 isolates during the study period were evaluated, the prevalence
of penicillin non-susceptibility S. pneumoniae ranged from 0% (Malta)
to 36% (Algeria) (median: 29% [interquartile range 18% – 33%]).
Except for Tunisia, macrolide non-susceptibility in S. pneumoniae was
generally lower than penicillin non-susceptibility for each country,
particularly in Turkey, where the difference was statistically significant
There was considerably greater variability for resistance within S.
aureus isolates [FIGURE 2]. Percentages of oxacillin resistance
- used as a marker for methicillin resistant Staphylococcus aureus (MRSA)
- varied from 10% in Lebanon to 65% in Jordan (median: 43% [IQR:
20 – 47%]). The most common resistance pattern showed co-resistance
to methicillin, erythromycin and gentamicin. These isolates were
particularly evident in Turkey where they accounted for more than
a third of all S. aureus isolates.
Even greater disparity was seen in the resistance patterns for E.
coli, mainly for fluoroquinolones and third generation cephalosporins
[FIGURE 3]. Resistance to third generation cephalosporins varied
from 3% in Malta to 72% in Egypt (median 18% [16 – 26%]) and
in the fluoroquinolones ranged from 5% in Algeria to 40% in Turkey
(median 27% [18 – 33%]). Multiresistant isolates were also
particularly evident. In fact, simultaneous resistance to four major
antimicrobial classes (aminoglycosides, third generation cephalosporins,
aminopenicillins, fluoroquinolones) was the second most common resistance
pattern seen and accounted for 13.7% of all isolates reported. Multiresistant E.
coli isolates were most commonly found in Egypt, comprising
more than half of all resistant isolates from that country, followed
by Turkey and Lebanon where around 30% were similarly multiply resistant
to three or more antibiotic groups.
Out of the five countries (Cyprus, Malta, Morocco, Tunisia and Turkey)
that provided data on more than 10 isolates of each of the enterococcal
species under investigation, only two reported vancomycin non-susceptibility
(intermediate or resistant): Turkey, with 0.9% (95% CI 0%–2%) E.
faecalis and 3.8% (2–7 %) E. faecium; and Cyprus,
with 2% (0%–14%) E. faecalis.
ARMed results have provided, for the first time, a standardised, comparable
snapshot on the prevalence of resistance in important clinically relevant
pathogens within hospitals in the southeastern Mediterranean. A median
of 43% for methicillin resistance within isolates of S. aureus confirms
that the Mediterranean region indeed constitutes a high prevalence
region for MRSA. It also correlates well with previous sporadic reports
from individual countries within the region [8-10]. It appears that
MRSA seems to be more widespread in the eastern Mediterranean than
in the south. Overall data from the hospitals in Cyprus, Egypt, Jordan
and Turkey all showed MRSA proportions in excess of 40%. Results from
the EARSS network, using the same methodology, have reported MRSA proportions
in excess of 30% from Croatia, France, Greece, Israel and Portugal
[11,12]. This would therefore indicate that the whole of the Mediterranean
region is a high prevalence region for MRSA.
On the other hand, resistance within E. coli to third generation
cephalosporins, and by association possibly extended-spectrum beta-lactamase
(ESBL) and/or Amp-C enzyme production, appears to be more significant
to those previously reported in the region. This seems especially the
case in the eastern Mediterranean where the centres in Turkey, Lebanon,
Jordan and Egypt reported average proportions in excess of 20%. The
figure of 72% resistance to third generation cephalosporins reported
from Egypt is one of the highest figures recorded for this resistance
trait. Nevertheless indications of high level resistance within Gram
negative pathogens in this region are not new. Bouchillon and colleagues,
studying isolates from 38 centres in 17 countries, reported the incidence
of ESBL production in Enterobacteriacae to be at its highest in their
Egyptian centres at 38.5% . El Kholy et al noted that 62% of E.
coli isolated from blood cultures in three Cairo hospitals were
non-susceptible to ceftazidime . The ARMed results seem to confirm
these previous reports and indicate that the situation may be even
more acute and widespread throughout the Mediterranean region than
previously indicated. In addition the presence of co-resistance to
other antibiotic groups further compounds the challenge posed by such
In contrast, the proportions of penicillin non-susceptibility in Streptococcus
pneumoniae (PNSP) isolates from the ARMed laboratories are broadly
in line with those already reported in centres within other Mediterranean
and Middle Eastern countries [15,16]. PNSP levels seem to be uniform
throughout the region and the apparent differences seen between eastern
and southern Mediterranean centres in S. aureus and E.
coli were not found in pneumococci. It is also interesting to
note that, contrary to reports from the European countries of the
region where macrolide resistance in pneumococci often exceeds that
of penicillin [15, 16], erythromycin non-susceptibility appears to
be less prevalent in the southeastern Mediterranean countries. Finally,
the presence of vancomycin resistance in enterococci from ARMed laboratories
in Turkey supports previous reports from this country .
The use of routinely collected clinical laboratory data provides the
advantage that epidemiological conclusions mirror the day-to-day situation
in the participating institutions. Furthermore, the choice of blood
culture isolates minimises sample bias and reflects the clinical situation
in the more severe infections. Unlike patients with less critical infections,
such as those of the respiratory and urinary tract, most patients with
signs of sepsis or meningitis will probably have a microbiological
sample taken. In addition, the major strength of the ARMed study resides
in the common methodology used throughout the different centres in
the nine participating countries. Any such study has the limitation
of depending on the accuracy and validity of the individual participating
laboratories, which can vary, especially in limited resource countries.
It is also hampered by the inability to perform third party reference
laboratory verification and do more detailed investigation in results
of particular significance. Nevertheless, the concurrent satisfactory
quality assurance results would suggest that this potential limitation
did not prejudice the conclusions reached from the preliminary data
collected by ARMed-EARSS to any significant degree .
In addition to the direct repercussions for the countries of the Mediterranean
region , the epidemiology of resistance in the southern and eastern
Mediterranean also has European implications. Human mobility in this
region is highly significant, in terms of both recognised travel (particularly
tourism) and the results of migration. The importation of multiresistant
organisms to European hospitals via patients arriving from countries
within the Mediterranean region is well documented [20,21]. Such an
occurrence may result in the possibility of subsequent intra-institutional
spread with the potential for an outbreak [22,23]. Prior knowledge
of the epidemiology of resistance in the Mediterranean region will
therefore facilitate the introduction of effective interventions on
initial contact with patients originating from this region and who
may be potentially colonised or infected with multiresistant organisms.
It should also prove beneficial for stakeholders in the countries involved
to plan and implement correct antibiotic stewardship programmes to
attempt control and possibly reduction of the incidence of antimicrobial
resistance in pathogens of critical importance .
The preliminary results from the ARMed project have started to shed new
light on the incidence of antimicrobial resistance in the south and
east of the Mediterranean. They appear to support and accentuate previous
sporadic reports suggesting a high prevalence in this region and indicate
that this is particularly the case in the eastern region where multiresistance
in S. aureus and E. coli seem to be especially high,
and higher than that reported in the other countries of the Mediterranean.
This picture will become clearer once the full duration of the study
is completed and a more comprehensive isolate database is established.
This study was undertaken as part of project ARMed (Antibiotic Resistance
Surveillance & Control in the Mediterranean region) which is funded
by the European Commission under the INCOMED programme of the DG Research
Fifth Framework Protocol (ICA3-CT-2002-10015).