Ziad Daoud

Countrywide Spread of Community- and Hospital-Acquired Extended-Spectrum β-Lactamase (CTX-M-15)-Producing Enterobacteriaceae in Lebanon

ABSTRACT A prospective study was carried out to assess the extent of carriage of extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae at both hospital and community levels in Lebanon. A total of 1,442 fecal samples were collected from hospital-based patients and 58 from health care workers of six Lebanese tertiary care general hospitals located in different areas of Lebanon between January and March 2003. A total of 382 fecal samples were also collected from healthy subjects between April and June 2003. The samples analysis led to the identification of 118 strains as ESBL producers based on the synergistic effects between clavulanate and selected β-lactams (ceftazidime and cefotaxime). These strains were isolated from 72 subjects: 61 patients, 2 health care workers, and 9 healthy subjects. One representative strain per subject was selected, and a total of 72 nonduplicate ESBL producers, including a high majority of Escherichia coli (n = 56), Klebsiella pneumoniae (n = 9), Enterobacter cloacae (n = 6), and Citrobacter freundii (n = 1), were characterized. The molecular analysis revealed that the majority of the strains (83%) express CTX-M-15 ESBL (pI 8.6). SHV-5a ESBL (pI 8.2) was produced by 18% of the strains. DNA macrorestriction analysis of ESBL-producing E. coli presented 38 different genotypes, revealing the absence of clonal link among these strains. In addition to the fact that the present study highlights the emergence and the countrywide dissemination of CTX-M-15-producing E. coli in Lebanon, it represents the first report of an SHV-5a-producing C. freundii.

A Plasmid-Borne blaOXA-58 Gene Confers Imipenem Resistance to Acinetobacter baumannii Isolates from a Lebanese Hospital

ABSTRACT We investigated the basis of the carbapenem resistance of 17 multidrug-resistant Acinetobacter baumannii clinical isolates collected from 2004 to 2005 at the Saint George University Hospital in Beirut, Lebanon. A. baumannii isolates were clonally related and were susceptible to colistin and trimethoprim-sulfamethoxazole, susceptible or intermediate to ampicillin-sulbactam and meropenem, and resistant to all other antimicrobials. Conjugation experiments demonstrated that resistance to imipenem could be transferred along with a plasmid containing the carbapenem-hydrolyzing oxacillinase blaOXA-58 gene. The plasmid that we called pABIR was 29,823 bp in size and showed a novel mosaic structure composed of two origins of replication, four insertion sequence (IS) elements, and 28 open reading frames. The blaOXA-58 gene was flanked by IS18 and ISAba3 elements at the 5′ and 3′ ends, respectively. The production of the carbapenem-hydrolyzing oxacillinase OXA-58 was apparently the only mechanism for carbapenem resistance in A. baumannii isolates causing the outbreak at the Lebanese Hospital.

Molecular epidemiology of carbapenem-resistant Acinetobacter baumannii strains in intensive care units of multiple Mediterranean hospitals

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Antibacterial Activity of the Extracts Obtained from Rosmarinus officinalis, Origanum majorana, and Trigonella foenum-graecum on Highly Drug-Resistant Gram Negative Bacilli

Our aim was to determine the antimicrobial activity of three selected plants ( Rosmarinus officinalis, Origanum majorana, and Trigonella foenum-graecum) against Extended Spectrum Beta Lactamase (ESBL)—producing Escherichia coli and Klebsiella pneumoniae— and to identify the specific plant fraction responsible for the antimicrobial activity. The plants were extracted with ethanol to yield the crude extract which was further subfractionated by different solvents to obtain the petroleum ether, the dichloromethane, the ethyl acetate, and the aqueous fractions. The Minimum Inhibitory Concentrations (MIC) and Minimum Bactericidal Concentrations (MBC) were determined using broth microdilution. The MICs ranged between 1.25 and 80  𝜇 g / 𝜇 l . The majority of these microorganisms were inhibited by 80 and 40  𝜇 g / 𝜇 l of the crude extracts. The petroleum ether fraction of Origanum majorana significantly inhibited 94% of the tested strains. Ethyl acetate extracts of all selected plants exhibited relatively low MICs and could be therefore described as strong antibacterial.

Escherichia coli Isolated from Urinary Tract Infections of Lebanese Patients between 2000 and 2009: Epidemiology and Profiles of Resistance.

The purpose of this study was to investigate the bacterial etiology of urinary tract infections in one of the busiest hospitals of Lebanon and to examine the epidemiologic and microbiologic properties of Escherichia coli isolated from urinary tract infections of Lebanese patients over a 10-year period. Methods. This retrospective study analyzed the data generated between 2000 and 2009 (10,013 Gram-positive and Gram-negative bacteria). Bacterial identification was based on standard culture and biochemical characteristics of isolates. Antimicrobial susceptibility was tested by the disk diffusion method, and ESBL production was detected by synergy with third-generation cephalosporins and amoxiclav. Results. E. coli was the most frequent isolate throughout the ten years (60.64% of the total isolates). It was followed by Klebsiella pneumoniae and Proteus sp., Pseudomonas aeruginosa, Enterococcus sp., and Streptococcus agalactiae. E. coli occurred more frequently in women (69.8%) than in men (61.4%). The lowest percentage of susceptibility of E. coli was manifested against piperacillin and ampicillin. An increase in the production of ESBL was observed (2.3% in 2000 to 16.8% in 2009). Conclusions. The etiology of urinary tract infections and their susceptibility profiles are important to be evaluated in countries like Lebanon where a severe misuse of antibiotics at all levels is observed.

Surveillance of antimicrobial resistance in Lebanese hospitals: retrospective nationwide compiled data.

Antimicrobial resistance is closely linked to antimicrobial use and is a growing concern worldwide. Antimicrobial resistance increases healthcare costs substantially in many countries, including Lebanon. National data from Lebanon have, in the most part, been limited to a few academic hospitals. The Lebanese Society of Infectious Diseases conducted a retrospective study to better describe the antimicrobial susceptibility patterns of bacterial isolates in Lebanon. Data were based on records retrieved from the bacteriology laboratories of 16 different Lebanese hospitals between January 2011 and December 2013. The susceptibility results of a total 20684 Gram-positive and 55594 Gram-negative bacteria were analyzed. The prevalence rate of methicillin-resistant Staphylococcus aureus was 27.6% and of vancomycin-resistant Enterococcus spp was 1%. Streptococcus pneumoniae had susceptibilities of 46% to oxacillin, 63% to erythromycin, and 98% to levofloxacin. Streptococcus pyogenes had susceptibilities of 94% to erythromycin and 95% to clindamycin. The mean ampicillin susceptibility of Haemophilus influenzae, Salmonella spp, and Shigella spp isolates was 79%, 81.3%, and 62.2%, respectively. The extended-spectrum beta-lactamase production rate for Escherichia coli was 32.3% and for Klebsiella spp was 29.2%. Acinetobacter spp showed high resistance to most antimicrobials, with low resistance to colistin (17.1%). Pseudomonas spp susceptibilities to piperacillin-tazobactam and imipenem were lower than 80% (79.7% and 72.8%, respectively). This study provides population-specific data that are valuable in guiding antimicrobial use in Lebanon and neighbouring countries and will help in the establishment of a surveillance system for antimicrobial resistance following the implementation of a nationwide standardization of laboratory methods and data entry.

Carriage of beta-lactamase-producing Enterobacteriaceae among nursing home residents in north Lebanon

BACKGROUND Multidrug-resistant (MDR) Enterobacteriaceae can cause severe infections with high morbidity, mortality, and health care costs. Individuals can be fecal carriers of these resistant organisms. Data on the extent of MDR Enterobacteriaceae fecal carriage in the community setting in Lebanon are very scarce. The aim of this study was to investigate the fecal carriage of MDR Enterobacteriaceae among the elderly residents of two nursing homes located in north Lebanon. METHODS Over a period of 4 months, five fecal swab samples were collected from each of 68 elderly persons at regular intervals of 3-4 weeks. Fecal swabs were subcultured on selective media for the screening of resistant organisms. The phenotypic detection of extended-spectrum beta-lactamase (ESBL), AmpC, metallo-beta-lactamase (MBL), and Klebsiella pneumoniae carbapenemase (KPC) production was performed using the beta-lactamase inhibitors ethylenediaminetetraacetic acid, phenylboronic acid, and cloxacillin. A temocillin disk was used for OXA-48. Multiplex PCRs were used for the genotypic detection of ESBL and carbapenemase genes, and sequencing was performed to identify CTX-M-15. The medical records of each subject were reviewed on a regular basis in order to assess the risk factors associated with MDR Enterobacteriaceae fecal carriage. RESULTS Over the study period, 76.5% of the recruited elderly persons were at least one-time carriers. A total of 178 isolates were obtained. Phenotypic testing revealed that 91.5% of them were ESBL producers, 4% were AmpC producers, 2.8% were co-producers of ESBL and AmpC, and 1.7% were co-producers of OXA-48 and ESBL. Recent antibiotic intake was found to be the only independent risk factor associated with the fecal carriage of MDR Enterobacteriaceae. CONCLUSIONS The high prevalence of MDR Enterobacteriaceae detected in this study and the emergence of carbapenem resistance is alarming. Efficient infection control measures and antibiotic stewardship programs are urgently needed in these settings in order to limit the spread of resistant strains.

Results from the Survey of Antibiotic Resistance (SOAR) 2011–13 in the Gulf States

OBJECTIVES To provide surveillance data on the susceptibility of community-acquired respiratory tract isolates from four Gulf and Near East countries from 2011 to 2013. METHODS MICs were determined using Etests(®) for all antibiotics evaluated except erythromycin, where testing was by disc diffusion. Susceptibility was assessed using CLSI, EUCAST and pharmacokinetic/pharmacodynamic (PK/PD) breakpoints. RESULTS Seven hundred and twenty-six respiratory isolates comprising 265 isolates of Streptococcus pneumoniae, 125 isolates of Streptococcus pyogenes and 336 isolates of Haemophilus influenzae were collected from Bahrain, Lebanon, Oman and the United Arab Emirates (UAE). Among S. pneumoniae, susceptibility to penicillin was low in the UAE and Bahrain. Macrolide susceptibility was ∼45%-60% in the UAE and Oman but higher in Lebanon (73.7%) and Bahrain (84%-85%). Penicillin susceptibility using CLSI intravenous breakpoints was >85% in all countries. Antibiotic susceptibility of S. pneumoniae was lower in UAE and Oman. Among S. pyogenes isolates, resistance to erythromycin was highest in Oman (31.6%) but <20% in the other countries. In H. influenzae, susceptibility to most antibiotics was high, except for ampicillin in Lebanon (70.2%) and amoxicillin in Oman (95.4%). Lebanon also had a high percentage (14.9%) of β-lactamase-positive isolates with non-susceptibility to ampicillin. Amoxicillin/clavulanic acid susceptibility was >95% in all countries. Use of EUCAST versus CLSI breakpoints demonstrated profound differences for cefaclor and cefuroxime in S. pneumoniae and H. influenzae, with EUCAST showing lower susceptibility. CONCLUSIONS There was considerable variability in susceptibility among countries in the same region. Thus, continued surveillance is necessary to track future changes in antibiotic resistance.

Detection of genotoxicity in hospital wastewater of a developing country using SOS chromotest and Ames fluctuation test

Background: Hospitals discharge considerable amounts of chemicals in their wastewaters that may be genotoxic or present serious health hazards. The genotoxic potential of wastewater in a Lebanese University Hospital was evaluated using the SOS Chromotest and the Ames fluctuation test. Different concentrations were tested to determine the recommended dilution for each sample to decrease its genotoxicity. Methods: The samples were taken from 5 different pits, 2 times per day in the morning and in the afternoon during two 1-week (5 days) periods in February and August 2011. SOS Chromotest and the Ames fluctuation were used to test genotoxicity. Results and conclusions: This study revealed that hospital wastewater was mostly genotoxic. 50% of the samples were positive for genotoxicity in the SOS Chromotest and 67.5% in the Ames fluctuation test. Genotoxicity of the sample was affected by the time, day, and season of sample collection. Different pits, representing different wastewater collection points, also varied with respect to the intensity of genotoxicity. Other genotoxic tests are currently underway to further evaluate the toxicity of these samples and to identify the genotoxic com pounds. This study shows that hospital wastewater must be carefully monitored and proper disposal or treatment measures need to be implemented.

A novel mutation in pmrB mediates colistin resistance during therapy of Acinetobacter baumannii

Acinetobacter baumannii is a highly versatile nosocomial pathogen. Multidrug resistance among A. baumannii isolates led to the use of colistin, subsequently giving rise to colistin-resistant strains. In this study, the genetic and phenotypic profiles of two colistin-resistant A. baumannii isolates were investigated. Two A. baumannii isolates were obtained from Patient 1 (C071 and C440) and three isolates were obtained from Patient 2 (C080, C314 and C428). Susceptibility profiles were determined by VITEK®2 and Etest. Clonality was determined by RAPD analysis and trilocus multiplex PCR. The pmrCAB operon was sequenced and common carbapenemase genes were screened for by PCR. Doubling times, haemolysis, surface motility, biofilm formation, siderophore production and proteolytic activity were phenotypically determined. Finally, whole-genome sequencing was performed for all five isolates. Isolates C440 and C428 were resistant to colistin and were clonally identical to their sensitive counterparts. The cause of colistin resistance was traced to the previously described P233S mutation in pmrB of C440 and to a novel ΔI19 mutation in pmrB of C428. blaOXA-58-like and blaGES-5 from the strains of Patients 1 and 2, respectively, were also detected. C440 had attenuated proteolytic activity and was positive for siderophore production compared with C071. No difference in in vitro virulence was detected between isolates C080, C314 and C428. In conclusion, one common and one novel mutation were encountered in pmrB from two distinct colistin-resistant A. baumannii isolates. These mutations caused colistin resistance during therapy in two distinct clones, and only one of them had altered in vitro virulence.