Antimicrobial resistance in Lebanon
George F Araj, PhD
American University of Beirut Medical Center, Beirut, Lebanon
The increase in resistance to antimicrobial agents among microorganisms has been recognized worldwide and Lebanon
is no exception. Since the cessation of civil war in the early 1990s, several studies conducted at the American
University of Beirut Medical Center have demonstrated the antimicrobial susceptibility patterns of bacteria (1-6),
mycobacteria (7) and Candida (8)
Moreover, an antibiogram annual report is generated for the associated 450-bed teaching hospital which provides
acute and tertiary care to patients of all ages in Lebanon. Each year, the hospital has approximately 16,000 admissions,
90,000 outpatient visits and 30,000 cases treated at the emergency unit. High frequency of antimicrobial resistance
is found among bacteria isolated at the American University of Beirut Medical Center (Table 1).
Observed Antibiotic Resistance
Among the Gram-positive cocci, the frequency of methicillin-resistant Staphylococcus
aureus (MRSA) rose from 3% in 1971 to 38% in 1998. Approximately
one-third of the penicillin-resistant Streptococcus pneumoniae had a penicillin MIC >1 ug/ml. Resistance to macrolides also appears
to be on the rise: Between 1992 and 1998, erythromycin resistance among S.
pyogenes and S.
viridans isolates rose from zero to 8% and 4% to 20%, respectively.
These, however, remain uniformly susceptible to penicillin. Thus far, no vancomycin-resistant enterococci have
been detected. Currently, enterococcus isolates are being collected to determine vancomycin and aminoglycoside
resistance based on established criteria.
Among Gram-negative bacteria in 1998, the prevalence of strains with extended spectrum beta-lactamases (ESBLs)
among Escherichia coli
and Klebsiella pneumoniae
isolates were 3.3% and 6.4%, respectively. Significant rates of multidrug-resistant nonfermenters have been observed
mainly among Acinetobacter spp.
and Pseudomonas spp.
Resistance to all commonly used antimicrobial agents was detected among four isolates of P.
aeruginosa. Strains of Acinetobacter
spp. susceptible only to imipenem were frequently encountered.
No antimicrobial resistance was detected among Salmonella
typhi; contrarily, non-typhi Salmonella
spp. exhibited resistance to ampicillin ranging from 17%
to 30% and to trimethoprim-sulphamethoxazole ranging from 6% to 15%.
Among Campylobacter spp.,
high resistance rates were encountered against several antimicrobial agents: ampicillin (31%), erythromycin (53%),
cipro-floxacin (61%), tetracycline (51%) and chloramphenicol (23%).
Drug resistance among M. tuberculosis
was also high for isolates recovered from both newly diagnosed cases and previously treated cases with higher resistancce
rates being observed in the latter group (Table 2). Overall, 14.6% of the isolates were resistant to two or more
Resistance rates of 0% to 6% were found in C. albicans against the tested antifungal drugs and in C. tropicalis only against itraconazole
(17%) (Table 3).
Bacterial, mycobacterial and Candida
isolates from Lebanon generally show high rates of antimicrobial resistance. Comparing these rates with those from
other regions in the world, Lebanon seems to fall between figures reported from the Persian Gulf countries which
are higher and those from medical centers in the United States and Europe which are lower. Continuous education,
surveillance and control programs are warranted to combat these high antimicrobial resistance rates in both Lebanon
and worldwide (9).
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