RESEARCH PROJECTS
Bacterial Endotoxin (LPS) LPS has a broad spectrum of activities. For years, the investigator
has been studying various aspects of LPS. These include; structure-function
relationship, effect on platelets, ability to induce CSF production, means
of neutralizing it’s hypotensive and other effects, effect of antibiotics
and aspirin on it’s biological activity, it’s interaction with the CD14
receptor and the effect of hemoglobin on some of it’s properties. Ongoing
research involves the investigation of it’s possible role in the Inflammatory
Response Syndrome as a consequence of cardiac by-pass. A.M. Abdelnoor.
(Supported by AUB-URB.)
Human Leucocyte Antigens (HLA) HLA class I and II frequencies in Lebanese religious groups
were determined. HLA associations with certain diseases (in Lebanese) and
recurrent spontaneous abortions were investigated. The effect of HLA matching
on the duration of survival of kidney transplants is being investigated.
HLA profiles are being determined by the Complement Dependent Cytotoxicity
test. Recently, DNA typing (alleles) has been introduced in the investigators
laboratory and is being pursued. A.M. Abdelnoor. (Supported by LNCSR.)
Infectious diseases Immunological (mainly ELISA, Western Blot, Radial Immunofiffusion)
and/or Molecular (mainly PCR) techniques have been utilized to study infectious
agents and/or diseases. Infectious diseases or agents included Tuberculosis,
Typhoid, Brucellosis, Hemophilus influenza, Streptococcus sanguis,
Measles and SSPE, CMV, HIV, HTLV I/II and Hepatitis B and C. A number of
studies involved prevalence aspects. Ongoing research involves the genotyping
of HIV isolates from Lebanese (in collaboration with CDC) and a study on
the prevalence of anti-HTLV I/II antibodies in patients on hemodialysis.
A.M. Abdelnoor. (Supported by MPP and Center for Disease Control (CDC).)
DNA vaccines In a pilot study we succeeded in constructing a plasmid which
induced immunity in mice against Salmonella typhimurium. Plans are
underway to produce a DNA vaccine against Pseudomonas aeruginosa.
A.M.
Abdelnoor. (Supported by AUB-URB.)
Genotyping of HIV isolated from patients in Lebanon Twenty-six HIV isolates from patients in Lebanon have been
genotyped. Ten belonged to HIV-1 subtype A and 10 to subtype B. Work in
progress deals with genotyping the remaining 6 isolates which did not belong
to subtypes A or B. A.M. Abdelnoor, G. Matar, J. Moukhbat and
M. Uwaydah, W. Heneine. (Supported Center for Disease Control.)
Identification of causative allergens in allergic asthma and rhinitis In one study we identified the causative allergens in a group
of Lebanese asthmatics. This study is being pursued to include patients
with rhinitis. ELISA techniques are being utilized in this project. For
publications see CV. A.M. Abdelnoor and G. Zaytoun. (Supported
by MPP.)
PCR-RFLP analysis of the TEM Beta-lactamase gene in gram-negative bacteria with unusual susceptibilities to beta-lactam antibiotics We have typed TEM-Beta lactamase gene by PCR-RFLP analysis
on gram -ve bacteria with unusual susceptibilities to beta-lactam antibiotics.
Twenty seven gram -ve isolates were obtained from patients and ten reference
strains of various TEM types were used. PCR-amplification of an 858 bp
fragment on the TEM beta-lactamase gene was done using specific primers.
Restriction Fragment Length Polymorphism (RFLP) analysis was done using
HhaI,
MseI and Sau3AI restriction endonucleases and composite patterns
were generated. Our data have shown that 25/27 test isolates were nitrocefin
positive. Of these, nine showed along with the ten reference strains the
858 bp fragment. These nine consisted of: one
E. coli and one P.
aeruginosa resistant to aztreonam and susceptible to all tested other
beta-lactams, one P. aeruginosa and two S. maltophilia, susceptible
to ceftazidime and resistant to all other tested beta-lactams. Restriction
analysis done on the nine PCR amplicons in comparison to the reference
strain, have shown that: 1) six had the TEM1-A composite profile, and 2)
three had the composite profile for TEM-5. G.M. Matar, N. El Haddad,
and M. Uwaydah. (Supported by AUB-DTS.)
Characteristics of pathogens encountered in otitis externa in a group of Lebanese patients A prospective study of 63 patients who presented to the emergency
room at the American University of Beirut, Medical Center during a 3-months
period with the diagnosis of either unilateral or bilateral otitis externa.
The incidence of bilateral ear involvement was 20%. The organisms recovered
were mainly Pseudomonas aeruginosa, and/or Staphylococcal species.
P.
aeruginosa isolates were all susceptible to aminoglycosides, oral quinolones
and ceftazidime. In conclusion, our study has shown that the commonest
pathogen recovered from cases of otitis externa was P. aeruginosa
and was associated with yellowish to greenish dischaand moderate to severe
swelling. Studies are underway to further characterize these isolates at
the molecular level and determine a relationship between severity of symptoms
and particular genotypes of P. aeruginosa.
G.M. Matar, H. Harakeh,
and U. Hadi. (Supported by LNCSR.)
Comparative analysis of random amplified polymorphic DNA subtypes of Pseudomonas aeruginosa isolates recovered from patients with otitis external in relation to severity of symptoms Random amplified polymorphic DNA (RAPD) analysis was done
on 34 isolates of Pseudomonas aeruginosa obtained from 22 patients
who presented to the emergency room in a medical center during a 3-month
period with the diagnosis of either unilateral or bilateral otitis externa.
Our data have shown that 19 RAPD patterns [A-S], were obtained out of the
34 isolates. Six of 20 isolates had RAPD pattern B. Six other isolates
of the 20 had RAPD pattern C. The remaining 4 of 10 patients had RAPD patterns
other than B and C. The results may indicate that 2 strains of P. aeruginosa
are responsible for severity of symptoms. G.M. Matar, H. Harakeh, and
U. Hadi. ( Supported by LNCSR.)
PCR-based detection and subtyping of bacterial etiology of otitis media with effusion in infected Lebanese children We developed and evaluated a two-step PCR-based protocol with
universal primers and genus-or species specific primers for the detection
of the most prevalent bacterial etiologies of otitis media with effusion
(OME) in children from Lebanese hospitals. DNA was extracted from samples,
and PCR was initially done with DNA extracts by using the universal primers
RW01 and DG74, which flank and ~ 370-bp fragment found in the 16S rRNA
gene of all bacterial species. For the identification of specific bacteria,
we used in three separate reaction mixtures, a genus-or species-specific
primer along with universal primer. RAPD was done on 9 H.influenzae
DNA samples using a 1-mer primer for subtyping purposes. Thirty-five samples
(74.5%) gave the expected 370-bp band. Of the 35 PCR-positive samples tested,
33 (94.3%) were positive for Haemophilus, 3 (8.6%) for Streptococcus,
and 10 (28.6%) for M. catarrhalis. Ten (28.6%) exhibited a mixed
infection and were positive for both Haemophilus and M. catarrhalis.
RAPD analysis showed a single pattern denoting the presence of a single
strain of H.influenzae in detected infections. G.M. Matar, N.
Sidani, M. Fayad, and U. Hadi. (Supported by LNCSR.)
Nosocomial bacterial pathogens: prevalence and antimicrobial resistance patterns This is an ongoing non-interventive surveillance study of
prevailing bacterial species and their susceptibility-resistance patterns
to a variety of antimicrobial agents in clinical use. Standard laboratory
procedures and API System were employed for precise species designation.
Susceptibility to different antimicrobial agents was tested using standardized
methods, including disk-agar diffusion and agar dilution techniques ( National
Committee for Clinical Laboratory Standards) and the Etest strips (AB Biodisk).
Strains producing extended-spectrum b -lactamases
were detected by ceftazidime/clavulanate combination strips. All results
have been complied in computer files and different susceptibility-resistance
profiles have been identified. M. Uwaydah (Supported by Pfizer Pharmaceutical
Corp.)
Occurrence, laboratory detection, and characterization of antimirobical heteroresistance in commonly encountered bacterial pathogens The term “heteroresistance” refers to a peculiar phenomenon
of antimicrobial drug resistance whereby different sub-populations within
the same pure strain exhibit varying susceptibility to antimicrobial agents.
Although its importance as a key feature of methicillin-resistant staphylococci
has been long established, its occurrence in other bacterial pathogens
has not received serious attention. The commonly used antimicrobial susceptibility
testing techniques are not reliable in detecting this phenomenon; consequently,
its relevance to drug resistance of bacterial pathogens, other than staphylococci,
has remained uncertain. In 1996, a preliminary study that was conducted
in our laboratory has demonstrated the presence of heteroresistance in
a variety of aerobic Gram-negative bacilli. This study aims at pursuing
those findings for the purpose of: (a) defining the frequency of heteroresistant
strains among commonly encountered bacterial pathogens, and (b) characterizing
the resistant sub-populations with reference to several parameters including
growth rate, metabolic activities, and antimicrobial susceptibility/resistance
patterns. M. Uwaydah. (Supported byAUB Research Committee/Massabki
Fund.)
Abdelnoor, A.M., Antigen processing/presenting and oncogenesis. Critical Reviews in Oncogenesis. 8 (4), 381-393, 1997. ———, Endotoxin research in Lebanon. International Endotoxin Society Newsletter, 7, 4-5, 1997. ———, MHC class I antigens in the Lebanese population. Eastern Mediterranean Health Journal, 3, 578, 1997. ———, Human Leucocyte Antigen frequencies. Lebanese Medical Journal, 46, 52-54, 1998. ———, HLA-B27 and the spondylarthropathies. Arthritis and Rheumatism, 41, 949, 1998. Abdelnoor, G.E., Matar, G.M., Charara, H., Abdelnoor, A.M., Detection of anti-hepatitis C-virus antibodies and hepatitis C-virus RNA in Lebanese hemodialysis patients. European Journal of Epidemiology, 13, 863-867, 1997. Bikhazi, A., Nahle, S., Kreydiyyeh, R., Haddad, R., Bitar, K., and Abdelnoor, A.M. Endotoxin binding on capillary endothelium and myocyte plasma membranes in perfused rat heart. Journal of Endotoxin Research, 4 (5), 45-51, 1977. Kanaan, S.A., Safieh-Garabedian, B., Haddad, J.F., Atweh, S.F., Abdelnoor, A.M., Jabbour, S.J., and Saadeh, N.E., Effects of various analgesic and anti-inflammatory drugs on endotoxin induced hyperalgesia in rats and mice. Pharmacology, 54, 285-297, 1997. Malak, R.R., and Abdelnoor, A.M., Human Leucocyte Antigen frequencies in a selected group of Lebanese Greek Orthodox. Lebanese Medical Journal, 45 (2), 75-83, 1997. Malak, R.R., Matar, G.M., and Abdelnoor, A.M., SDS-PAGE of Mononuclear cell protein lysates of HLA-identical twins and HLA non-identical individuals. DIRASAT, 24 (2), 105-111, 1997. Peiniazak, D.*, Baggs, J.*, Ju, D.J.*, Matar, G.M., Abdelnoor, A.M. Mokhbat, J.E. Uwaydah, M., Bizri. A.R., Ramos, C.A.*, Janini, L.M.*, Tanuri, A.*, Fridlund*, C., Schable, C.*, Heyndrickx, L.*, Rayfield, M.A.*, and Heneine, W., Evidence for introduction of HIV-2 and multiple HIV-1 subtypes in Lebanon. Emerging Infectious Diseases, 4, 649-656, 1998. Ramadan, F., Hamadeh, F., Abdelnoor, A.M., Identification of allergens in a selected group of asthmatics in Lebanon. European Journal of Epidemiology, 14 (7), 687-191, 1998. Matar, G., Aboul Khoudoud, W., Fayad, M., Mikati, M., Abdelnoor, A.M., A two step protocol for the identification of the etiology of bacterial meningitis in CSF by PCR-amplification of the 16S ribosomal RNA gene. Eastern Journal of Medicine, 4, 27-31, 1999. Matar, G.M., Hayes, P.S., Bibb, W.F., and Swaminathan, B., A listeriolysin O-based latex agglutination test for the rapid detection of Listeria monocytogenes in foods. Journal Food Protection, 60, 1-5, 1997. Matar, G.M., Jaalouk, D.E., and Uwaydah, M., PCR detection of methicillin resistance determinant (mecA, mecI-mecR1) genes in clinical isolates of staphylococci. Revue Medicale Libanaise, 9,145-148, 1997. Matar, G.M., Sidani, N., Fayad, M., and Hadi, U., Two-step PCR for the identification of the etiology of otitis media with effusion in infected Lebanese children. Journal Clinical Microbiology, 36, 1185-1118, 1998. Uwaydah, M., Khalil, A., Shamsuddine, N., Matar, F., and Araj, G.F., Brucella-infected ovarian dermoid cyst causing initial treatment failure in a patient with acute brucellosis. Infection, 36, 131-132, 1998. Uwaydah, M., Monitoring of antibiotic usage and bacterial
susceptibility patterns: a decade of experience with ceftazidime. Modern
Medicine, 15, 37-40, 1998.
ABSTRACTS,
PRESENTATIONS AND PROCEEDINGS
Abdelnoor, A.M., Matar, G.M., Naboulsi-Khalil, M., and Ramadan, F., diagnosis of tuberculosis using the 38kda antigen. The FASEB Journal. 13 (4), A635, 1999. Matar, G.M., Aboul khoudoud, W., Fayad, M., Mikati, M., and Abdelnoor, A.M., Two step PCR for the identification of etiology meningitis in CSF of infected patients. Abstracts of the American Society for Microbiology Annual Meeting, 98 (150), 1998. Hadi, U., Sidani, N, Fayad, M., Ramadan, H., and Matar, G.M., PCR-based identification and subtyping of the etiology of bacterial otitis media with effusion in infected children. American Society of Pediatric Otolaryngology (ASPO), Palm Beach, Fl., 98, P.28, 1998. Harakeh, H., Rizk, M., Uwaydah, M., and Matar, G.M., Random amplified polymorphic DNA typing of Enterococcus faecalis. American Society for Microbiology Annual Meeting 98th, Abstract no. C-89 P. 146, 1998. Matar, G.M., Aboulkhoudoud, W., Fayad, M., Mikati, M., and Abdelnoor, A., Identification of the etiology of bacterial meningitis in cerebrospinal fluid using a two-step PCR amplification of the 16S ribosomal RNA. Third International Meeting on Molecular Epidemiology and Evolutionary Genetics of Infectious Diseases (MEEGID-3), Rio De Janeiro, Bresil. Abstract no. 36. P.74,1998. Matar, G.M., Sidani, N., Fayad, M., and Hadi, U., PCR-based detection and subtyping of the etiology of otitis media with effusion in infected children. Annual Society of Microbiology Annual Meeting 99th, Chicago , IL., 1999. Harakeh, H.S., Abdelnoor, A.M., and Matar, G.M., Random amplified
polymorphic DNA typing of streptococcus sanguis isolated from human oral
cavity and dental caries. American Society for Microbiology Annual Meeting
99th, Chicago, IL., 1999.
Aboul khoudoud, W., PCR-detection of the etiology of bacterial meningitis and herpes simplex virus encephalitis in cerebrospinal fluid (1998). G.M. Matar. Anouti, F., Development and evaluation of a PCR-based assay for detection of the diarrheal enterotoxin-producing B. cereus isolates by amplification of a target sequence on hb1A gene (1997). G.M. Matar. Helwaneh, R., The antibacterial effect of the constituents of Nigella sativa oil (1997). A. M. Abdelnoor. Mikael, L., Effect of hemoglobin on the activity of bacterial lipopolysaccharide, (1997). A. M. Abdelnoor. Mansur, S., HLA class I and II typing of a selected group of Druze in Lebanon (1997). A. M. Abdelnoor. Sidani, N., PCR-identification of the bacterial etiology of
otitis media with effusion in children (1997). G.M. Matar.
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