Marwan Uwaydah

Antimicrobial susceptibility patterns of bacterial isolates at the american university medical center in Lebanon

In Lebanon, knowledge of the prevailing pattern of bacterial resistance to antimicrobial agents has been limited, particularly because of 15 years of civil strife. Thus, the current study was conducted to determine the antimicrobial susceptibility patterns of nonselected bacterial isolates recovered from recent clinical specimens, using the standardized disk agar diffusion technique. A total of 5216 isolates (1443 Gram positive and 3773 Gram negative) were examined. Over 92% of Staphylococcus aureus and coagulase-negative staphylococci (CNS) were resistant to penicillins. Methicillin resistance was more frequently noted among CNS (28%) compared with S. aureus (18%). For the pneumococci, 27% of the isolates were resistant to penicillin G. High but variable rates of multidrug resistance were encountered among Acinetobacter spp., Pseudomonas spp., Serratia spp., Citrobacter spp., and Enterobacter spp. Ampicillin resistance was detected in 65% of Escherichia coli and in 20% of Haemophilus influenzae isolates. Although one resistant Salmonella typhi strain was observed, 17% of other Salmonella spp. and 60% of Shigella spp. proved to be resistant to ampicillin, chloramphenicol, and cotrimoxazole. Among Vibrio cholerae isolates, high resistance to tetracycline (71%) and trimethoprim-sulfamethoxazole (94%) was observed. The overall antimicrobial resistance rates in Lebanon seem to fall between figures reported from the Arabian Gulf countries (higher) and those from medical centers in the United States (lower).

Moxalactam Therapy of Bacterial Meningitis in Adults

The therapeutic efficacy and attainable cerebrospinal fluid (CSF) concentrations of moxalactam, administered by intravenous drip in a dose of 2 g every 4 to 8 h, were evaluated in seven adult patients with bacterial meningitis. Streptococcus pneumoniae, Staphylococcus aureus, Pseudomonas aeruginosa, and Acinetobacter calcoaceticus var. anitratus, each caused infection in four patients, whereas Escherichia coli was the cause of infection in the other three patients. The mean moxalactam concentration in CSF was 14.7 μg/ml (range, 4.7 to 38 μg/ml) in the lumbar samples and 12.1 μg/ml (range, 4.4 to 27 μg/ml) in the ventricular samples. Depending on the time after antibiotic administration, the ratio of CSF to serum concentrations varied from 6.6 to 160%. Satisfactory improvement and negative CSF cultures were initially noted in all seven patients. Six patients were ultimately cured, and the death of the patient with Pseudomonas meningitis could not be clearly attributed to uncontrolled infection.

Treatment of typhoid fever with cefamandole.

Cefamandole therapy was evaluated in nine patients with typhoid fever. Six patients, including all five who received the antibiotic by continuous intravenous drip (8.0 g daily), were cured. Dosage schedules resulting in maintenance of antibiotic concentrations in serum high above the MIC seemed to correlate well with treatment success.

Cefazolin in the Treatment of Acute Enteric Fever

Cefazolin was used in the treatment of nine patients with acute enteric fever proven by positive blood cultures. In seven patients the causative organism was Salmonella typhi and in two it was Salmonella paratyphi B. Minimal inhibitory and minimal bactericidal concentrations of cefazolin against the nine isolates ranged between 1.95 and 3.90 μg/ml. Cefazolin was administered either intramuscularly or intravenously in a daily dose of 3 to 6 g for 11 to 16 days. The mean peak serum antibiotic concentration after a 0.5-g intravenous injection was 64.4 μg/ml, and the mean trough concentration, 3 h later, was 12.7 μg/ml. The highest serum inhibitory dilution at peak level was frequently 1/64, and at trough level it was 1/16 to 1/32. The acute infection was satisfactorily controlled in all patients. Phlebitis, complicating intravenous therapy, in five out of eight patients, was the only side effect observed. Relapse of typhoid fever, as documented by positive blood culture, occurred in one patient 11 days after treatment course was completed. More extensive clinical studies are required before drawing any conclusions regarding the efficacy of cefazolin in acute enteric fever.

Polymerase Chain Reaction Identification of Coagulase-Negative Staphylococci and of Strain Diversity and Spread of Staphylococcus epidermidis in a Major Medical Center in Lebanon

A 2-step polymerase chain reaction (PCR) assay and random amplification of polymorphic DNA (RAPD) analysis, respectively, were assessed to identify coagulase-negative staphylococci organisms to the species level and to determine the strain diversity and spread of Staphylococcus epidermidis, the most frequently isolated species, in a medical center in Beirut, Lebanon. Our data indicated that PCR was faster and was more efficient in identifying S. epidermidis isolates than is conventional biochemical testing. RAPD analysis have shown that S. epidermidis strains were scattered across the different clinical services, demonstrating various clusters of infection in the medical center.

Improved Primary Transplant Success Rates Using a Triple Regimen of Cyclosporine Microemulsion, Mycophenolate Mofetil and Prednisone

Group I included 105 consecutive primary renal transplants prospectively followed using a triple protocol of MMF (1 gm P.O. BID), ME-CsA (8-12mg/kg per day) and prednisone taper (60mg to 30mg over eight days). These included 34 Cadaver donors (CAD)(32.4%), 20 living unrelated donors (LUD)(19%), and 51 living related donors (LRD)(48.6%) that included five HLA identical and 46 haplo-identical and non-identical grafts. Group II included 137 consecutive transplant recipients with similar pretransplant demographics; CAD: 60/137 (43.8%), LUD 5 10/137 (7.3%), LRD 5 67/137 (48.9%), that included 11 HLA identical, and 56 HLA haplo-identical or nonidentical grafts. The number of retransplants in Group I (MMF) was five (4.76%) and in Group II 5 seven (5.11%). CsA dosing was diligently applied according to CsA target trough levels as previously reported. All patients received anti-CMV prophylaxis using high dose Acyclovir 3200 mg/day for D1/R2 and D2/R1 and Ganciclovir if ATG or OKT3 were used for rejection treatment.

Identification of an epidemic strain ofAcinetobacter baumanii using electrophoretic typing methods

Nosocomial infections due toAcinetobacter baumannii dramatically increased in a Lebanese medical center following an outbreak of hostilities in Lebanon in 1984. The incidence of infection caused by this organism has remained high in this institution, thus requiring the implementation of a strain typing system to aid in infection control. Three methods were investigated for their utility in differentiating among a representative group of 36 nosocomialAcinetobacter baumannii isolates obtained over a 10 month period from specimens of hospitalized patients. Isolates were typed by antibiogram analyses, plasmid fingerprinting, and total cell protein profiles. Only three distinct total cell protein profiles were detected, with one pattern accounting for 26 (72.2%) of the isolates. However, eight different plasmid profiles were observed, with 20 (55.5%) isolates having the same profile. Eleven distinct antibiograms were seen with the most prevalent pattern occuring in 21 isolates. Twenty of the 21 (95%) isolates with the common antibiogram also had the same plasmid profile and total protein profile (44.4% of total isolates). The combination of these three typing methods was useful in tracing the spread of these organisms in the medical center. The data obtained suggest the distribution of a common strain among at least six wards of this hospital.

Influence of HLA disparity, immunosuppressive regimen used, and type of kidney allograft on production of anti-HLA class-I antibodies after transplant and occurrence of rejection

We studied the effects of HLA disparity, immunosuppressive regimen used, and the type of kidney allograft on production of anti-HLA antibodies after transplant and the occurrence of rejection episodes. Five living-unrelated donors and 4 living-related donors kidney recipients received quadruple therapy (including sirolimus and mycophenolate mofetil). Fifteen living-unrelated donors and 19 living-related donors received triple therapy (excluding sirolimus). A single bolus of 4 to 6 mg/kg rabbit anti-human T-lymphocyte immune serum was included with both regimens. Recipients were studied over a 3-year period. Human leukocyte antigen profiles were determined by DNA (SSP) typing, and anti-HLA class-I antibodies were determined by the complement-dependent microcytotoxicity assay and an enzyme-linked immunosorbent assay. The degree of HLA disparity did not appear to affect anti-HLA antibody production or the occurrences of rejection episodes. None of the patients who received quadruple therapy developed anti-HLA class-I antibodies. Two living-unrelated donors and 2 living-related donors recipients who received triple therapy developed anti-HLA class-I antibodies. One of the 2 living-unrelated donors antibody-positive patients rejected the kidney and returned to dialysis, and the other patient has normal graft function 3 years after the transplant. The 2 living-related donors patients with normal graft function were antibody-positive 1 year after the transplant but were antibody-negative at 2 and 3 years after transplant. Sirolimus appeared to inhibit production of antibodies after transplant. Moreover, use of present day immunosuppressive agents diminishes the role of HLA matching in relation to the occurrence of rejection episodes.

Brucella melitensis infection of a branchial cyst.

Apostolova E, 2002, J INFECTION, V44, P271, DOI 10.1053-jinf.2002.0983; Corbel MJ, 2005, HARRISONS PRINCIPLES, P914; Huang RY, 2000, INT J PEDIATR OTORHI, V54, P167, DOI 10.1016-S0165-5876(00)00355-4; Lo Re V, 2001, J CLIN MICROBIOL, V39, P4210, DOI 10.1128-JCM.39.11.4210-4212.2001; Uwaydah M, 1998, INFECTION, V26, P131, DOI 10.1007-BF02767777

PCR-Based Detection, Restriction Endonuclease Analysis, and Transcription of tonB in Haemophilus influenzae and Haemophilus parainfluenzae Isolates Obtained from Children Undergoing Tonsillectomy and Adenoidectomy

ABSTRACT We developed and evaluated a PCR-based-restriction endonuclease analysis method to detect and analyze the tonBgene of Haemophilus influenzae and Haemophilus parainfluenzae from pediatric patients undergoing tonsillectomy and adenoidectomy. Multiple sites from the same patient, including the surface of adenoids and tonsils, as well as the core of tonsils, were cultured on chocolate agar and identified using standard procedures and the API NH Kit. A total of 55 H. influenzae isolates were recovered from different sites of 20 patients, and 32 H. parainfluenzae isolates were recovered from various sites of 12 patients. DNA was extracted from American Type Culture Collection strains and test isolates by the PureGene kit. Two primers, G1 (21-mer) and G2 (23-mer), were designed by us to amplify by PCR the tonB gene that consists of an 813-bp fragment. A nested PCR using primers T1 (23-mer) and T2 (24-mer) that flank an internal sequence to the gene of the order of 257 bp and restriction endonuclease digestion using XhoI and BglII were done to detect whether heterogeneity within the gene exists between the two species. Reverse transcription-PCR (RT-PCR) was finally done to detect transcription of the gene in both species. Our data have shown that the tonB gene was detected in both species. It is known to encode a virulent protein, TonB, in H. influenzae; however, demonstration of its presence in H. parainfluenzae is novel. Nested-PCR and restriction endonuclease analysis have shown that the tonB gene is apparently structurally the same in both species, with possible differences that may exist in certainH. parainfluenzae isolates. RT-PCR done on selected numbers of H. influenzae and H. parainfluenzae have shown that the tonB gene was transcribed in both species. This shows that the TonB protein, if expressed, may play a different role in the virulence in H. parainfluenzae since it is not needed for heme or heme complexes uptake as with H. influenzae.