Vol. 21, September, 2008

1/21 CHITINASE PRODUCTION BY SERRATIA MARCESCENS AND ITS ANTAGONISM AGAINST PLANT PATHOGENIC FUNGI.

Hoda H. El-Hendawy, Mohamed E. Osman and Marwa R. Abd El-Salam

Botany & Microbiology Department, Faculty of Science, Helwan University,

Ain Helwan, Egypt.

Five local S. marcescens isolates as well as a reference isolate were able to hydrolyze chitin when grown on nutrient agar containing 1% colloidal chitin. Chitinase production by the six isolates was further studied and found to be optimal with 1% colloidal chitin concentration, pH 7-9 at 30oC. Addition of gelatin to the medium containing 1% colloidal chitin increased chitinase production by the isolates including the reference one. In contrast, addition of corn oil, pectin and starch reduced the enzyme production by all isolates in relation to control containing colloidal chitin only. Differences in chitinase production was also obtained by the different isolates when addition of various nitrogen sources. The antagonistic activity of S. marcescens isolates was tested against some plant pathogenic fungi.

 

 

2/21 AEROBIC AND FACULTATIVE ANAEROBIC BACTERIA ISOLATED FROM UPPER RESPIRATORY TRACT OF LYBIAN PRESCHOOL CHILDREN

Kamel A. El-Ghareeb and Khaled M. Bofaris*

Dept. of Microbiology and Immunology, Faculty of Pharmacy, Al-Azhar University, Cairo, Egypt

*Dept. of E.N.T., Faculty of Medicine, Omar Almokhtar University, Al bida, Lybia

Acute and chronic respiratory tract infections are important health problems among young and adult ages, and have serious impact on economy in many countries. This study was performed to isolate and identify the bacterial causes of upper respiratory tract diseases in infants using standard biochemical and microbiological techniques. In this study 80 (44%) bacterial isolates were obtained from the 180 cases. In case of tonsillitis 38 (47.5%), followed by 20 bacterial isolates from cases of sinusitis (25%) and 22 bacterial isolates from chronic otitis media (27.5%) obtained from 95, 62 and 23 cases respectively. These findings revealed that the most common bacteria causing upper respiratory tract infections in infants were Staph. aureus (31.6%) followed by Proteus spp. and E. coli (16.3%) for each, Klebsiella spp. (8.8%) and P. aeruginosa (5%). Antibiotic sensitivity of bacterial isolates results showed that most isolated microorganisms were highly sensitive to Amikacin, Imipenem, Gentamicin, Ofloxacin, Cefotaxime and Rifampicin.

 

 

3/21 CORRELATION BETWEEN THE ROLE OF CELL FRACTION AND ANTIBIOTIC SUSCEPTIBILITY OF KLEBSIELLA PNEUMONIAE.

Fathy A. Mansour, Yehia A.O. Ellazek, Rawya I. Badr*

and Moustafa M. El-Shaer**

Department of Botany, Faculty of Science, Mansoura University, Egypt.

*Department of Medical Microbiology and Immunology Faculty of Medicine, Mansoura University, Egypt.

**Medical Specialized Hospital, Mansoura University, Egypt.

Klebsiella pneumoniae (K. Pneumoniae) is a Gram-negative opportunistic bacterial pathogen primarily infecting immunocompromised individuals who are hospitalized and suffer from severe underlying diseases. K. pneumoniae can cause a range of infections, from mild urinary tract infections to severe septicemia and bacterial pneumonia with mortality rates that may exceed 50%. The aim of this study was to detect the frequency of K. pneumoniae causing nosocomial infections in Mansoura University Hospitals with detection of different factors increase the risk of their acquisition. Also detection of strains that produce ESβLase enzyme as amajor cause of treatment failure in hospital infected patients. Moreover detection the presence of some genes which carry ESβLase enzyme. Besides that detection if the cell wall may be a cause of resistant beside the inside cell enzyme.Clinical samples were collected, regardless the type of infection and the sex of patients, This study was carried out over a period of 8 months from January 2006 to August 2006 . During that period 1368 samples were collected from different wards in Mansoura University Hospitals (MUHs). Out of 1368 samples, 172 yielded positive culture results for K. pneumoniae Phenotypic characterization was performed using cultural characteristics and morphological appearance in Gram stained smears and conventional biochemical reactions. API 20E was used to confirm isolation of K. pneumoniae. Resistogram using Kirbey Bauer method was conducted to study the antibiotic susceptibility of the isolates. All the isolated strains exhibited sensitivity to imipenem and most of them were sensitive to amikacin. Whereas very high resistant occured to Cefuroxime. Klebsiella pneumoniae were isolated especially from patients with abuse of broad spectrum antibiotics, prolonged hospital stay and Catheterized patient. Screening for ESβLs was performed using double disk synergy test, their production was detected in 51 cases at a percentage of 29.7%. Specific risk factors identified in patients infected with an ESBL-producing, included prolonged hospital stay, intubation, Catheterized patient and emprical exposure to antibiotics. PCR for detecting the presence of the genes SHV-2, CTX-M2 and OXA-1 from the isolated K. pneumoniae ESβLs was performed. The genes SHV-2, CTX-M2 and OXA-1 was detected in 51 (74.5%, 5.9% and 3.9%) respectively.Cell Fractionation used to detect if the cell wall may be a cause of resistant beside the inside cell wall enzyme. That occure when cell wall has impermeability to used antibiotic to enter inside. The present result found that resistant of some samples is not due to the inside cell wall enzyme but due to impermeability of cell wall.

 

 

4/21 BACTERIAL CONTAMINATION OF CURRENCY NOTES IN EGYPT

Kamel A. El-Ghareeb

Depart. of Microbiology and Immunology Faculty of Pharmacy, Al-Azhar University, Cairo, Egypt

In this study two hundreds and fifty samples of paper currency were collected from the general community in Cairo for bacteriological contamination. Bacteria isolated were S. aureus 15.69% Micrococci 4.8%, Bacillus 8%, E. coli 10.8% and both Klebsiella and Proteus 6.4%. Among dirty currency notes bacterial contamination were more (95%) than they were among clean (50%) and mint (0%) currency notes. Lower denomination notes were more likely to be contaminated than were higher denomination notes. Bacterial contamination were most frequent in notes obtained from butchers, (85%), followed by fish shop (80%), bus conductors 70%, food sellers 42% and Pharmacies 25% but Banks (0%). The most pathogenic bacteria isolated from currency notes were tested for antibiotic susceptibility. Isolates of different organism were resistant to some tested antibiotics. The most resistant organism was Proteus followed by Klebsiella spp. The results suggest that the currency notes contaminated with bacteria may serve as sources of infection and therapeutic problems especially that showing great antibiotic resistance. Personal hygiene to reduce risk of infection is recommended.

 

 

5/21 BACTERIAL FLORA OF CULTURED FISHES IN THE FISH FARM OF CROSS RIVER UNIVERSITY OF TECHNOLOGY, OBUBRA CAMPUS, NIGERIA.

Gabriel Ujong Ikpi and Ben Offem

Department of Fisheries, Faculty of Agriculture, Cross River University of Technology, Obubra Campus.

Random sampling of fish specimens with weights ranging from 170.0g to 240.0g from the Cross River University of Technology, Obubra Campus, numbering 120 from the cichlid and catfish families were investigated for the bacteria species present in them. The fish specimens Oreochromis niloticus, Tilapia zillii and Heterobranchus bidorsalis, were sacrificed by pitting and Inoculum from the fish organs cultured on McConkey agar (McC) and Trypticase soy agar (TSA). The media were incubated aerobically at 250C and 370C for 18 to 24 hours from which pure culture of the bacteria species were identified using standard procedures. The eight bacteria species identified were; Pseudomonas fluorescens, Aeromonas hydrophila, Proteus vulgaris, Escherichia coli, Staphylococcus aureus,Klebsiella aerogenes, Edwardsiella tarda and Flexibacter columnaris, with bacterial loads ranging from 4.8 X 103 and 2.3 x 103 Colony Forming Units (cfu)/g from the organs. The cfu of bacteria of fishes in the aquarium followed a pattern similar to that of the pond but was proportionately lower. (P< 0.05). The presence of Staphylococcus aureus and Escherichia coli in the fishes from the ponds is suggestive of faecal contamination. The data generated was subjected to Analysis of Variance (ANOVA). The clinical significance of their occurrence in human beings is discussed.

 

6/21 CHARACTERIZATION OF CRUDE OIL–DEGRADING MICROBIAL POPULATION IN CONTAMINATED ARABIAN GULF SOILS

Kawther F. Abed and Suaad S. Alwakeel

Botany Department, University of Riyadh, Riyadh, Saudi Arabia

Microorganisms play a crucial rule in the biodegradation and bioremediation of soils contaminated with crude oil or polycyclic aromatic hydrocarbons (PAH). Saudi Arabia, being one of the largest oil producing countries, no published data about the bacterial community involved in this economical, natural and environmentally safe process of bioremediation. The present study was undertaken to identify and characterize crude oil degrading bacterial population in 12 polluted oil field soil samples collected from the Eastern region. Five bacterial strains, consisting of Acinetobacter baumannii, Bacillus sp., Corynebacterium sp., Serratia marcescens and Sternotrophomonas maltophilia, were isolated from contaminated soil samples. Out of those 5 bacterial strains, Acinetobacter baumannii, Corynebacterium sp. and Serratia marcescens, showed very good growth on media containing Saudi Aramco Arabian Light crude oil as the only carbon source. These bacterial species were studied further for their abilities to degrade in vitro crude oil samples. Corynebacterium sp. (91.5%) and Acinetobacter sp., (85.4%) demonstrated better in vitro crude oil degradation than Serratia marcescens (82.7%). Based upon the random amplified polymorphic DNA polymerase chain reaction (RAPD-PCR) data and results of genetic similarity matrix analysis, these crude-oil biodegrading bacterial isolates could be clustered into two distant phylogenetic groups. Group-1 consisted of Acinetobacter baumannii, Cornybacterium sp. and Serratia marcescens which shared 23.5% genetic similarity whereas Group-2, consisting of Cornybacterium Sp and Serratia marcescens, shared 46.2% genetic similarity. To our knowledge this is the first molecular analysis ofhydrocarbon-degrading microbial populations in Arabian Gulf soils. It is hoped that our results will provide baseline data for future studies aiming at the bioremediation of crude-oil contaminated soil in Saudi Arabia.

 

 

7/21 IN VITRO BACTERICIDAL ACTIVITY OF CEFEPIME COMBINED WITH CIPROFLOXACIN, IMIPENEM, TOBRAMYCIN AND AMIKACIN AGAINST EXTENDED SPECTRUM β-LACTAMASE AND NON-EXTENDED SPECTRUM β-LACTAMASE PRODUCING ORGANISMS

Mansour E. Aggag, Mohamed A. Fawzy, Nadia M. El-Guink, Hesham M. Saeed and Nelly M.Abdel-Moneim

Department of Pharmaceutical Microbiology, Faculty of Pharmacy,

Alexandria University, Egypt

In a trial to overcome the resistance caused by the extended spectrum β-lactamase (ESBL)-producing isolates, a number of combinations consisting of cefepime (FEP) and one of the following antibiotics amikacin (AK), tobramycin (TOB), imipenem (IPM) and ciprofloxacin (CIP) were designed and assessed by the time-kill curve method. Combinations with a β-lactamase inhibitor, potassium clavulanate (4 mg/ml), were also included. These combinations were tested against two isolates of each K. pneumoniae (K6 and K11) and E. coli (E9 and E19); ESBL-producers and non-producers. Assessing these combinations against the non-ESBL producers (K6 and E19), synergy was demonstrated with no cell recovery from tobramycin/ cefepime combination when tested against both isolates. Complete killing of E19 was obtained by imipenem/cefepime and ciprofloxacin/cefepime combinations. The addition of potassium clavulanate increased greatly the killing rates of all the tested combinations against the ESBL-producing isolates leading to the complete killing of K11 and E9 demonstrating marked synergy. On the other hand, the presence of potassium clavulanate did not affect significantly the killing rates of ESBL non-producers.

8/21 PRODUCTION AND CHARACTERIZATION OF THERMOSTABLE β-GALACTOSIDASE BY FREE AND IMMOBILIZED ASPERGILLUS NIGER CULTURES

Rania M.A. Abedin, Ghada A.Yossef, Reem M. Allam and Samy A. El-Assar

Botany Department (Microbiology), Faculty of Science, Alexandria University,

Alexandria, Egypt

In the course of exploring new microbial sources of extracellular β-galactosidase, immobilized Aspergillus niger cells was found to excrete elevated quantities of a thermostable form of the enzyme. The enzyme activity was maximal when luffa pulp (LP) and sponge immobilized supports were used. The production of β-galactosidase improved significantly with immobilization, reached a maximum enzyme yield 1.492 U/ml by using luffa pulp (LP) as a support for immobilization of the Aspergillus niger mycelia, when compared with the enzyme activity produced by the free Aspergillus niger mycelia (1.298 U/ml). Optimal cultural conditions for maximum enzyme production by the free mycelia were lactose 1.5%, yeast extract 1%, KH2PO4 0.125%, MgSO4.7H2O 0.175% and wheat bran 4% and a cultivation time of 3 days at 33oC and pH 7 on a static state resulting in a maximal enzyme activity of (2.456) U/ml. While, the optimized culture medium for maximum enzyme production by the immobilized mycelia on LP was contained, maltose 1.5%, tryptone 1.2%, KH2PO4 0.125%, MgSO4.7H2O 0.2%, wheat bran 4% and (5g of LP cubes / 50ml flask) as an immobilization support for adsorption of Aspergillus niger mycelia and a cultivation time of 4 days at 33oC and pH 7 on shaken cultures resulting in a maximal enzyme activity of (2.773U/ml). Scanning electron microscope studies indicated the adsorption of Aspergillus niger mycelia to LP and sponge immobilization supports. Also, the effect of some reaction conditions on the activity of crude β-galactosidase from immobilized Aspergillus niger mycelia were studied resulted in 1.4-fold increased level of thermostable β-galactosidase. The pH and temperature optima of the crude enzyme extract were 5.4 and 60oC, respectively. The enzyme was stable at a temperature up to 80 oC retaining about 50% and 32% of the original activity after 15 min and 30 min of incubation at this temperature, respectively. Ca2+, Ba2+and Mn2+ stimulated the enzyme activity up to (16,11,4-fold), while Na1+, Cu2+, Zn2+ and Hg2+ inhibited the activity of β-galactosidase. Data collected in the present study are of value and indispensable when β-galactosidase from immobilized Aspergillus niger mycelia is employed in practical and industrial applications.

9/21 DESIGN OF TRIPLE ANTIBIOTIC COMBINATION SYSTEM EFFECTIVE AGAINST RESISTANT CLINICAL STRAINS OF PSEUDOMONAS AERUGINOSA.

Abd El-Ghany E. El-Khouly, Hamida M. Abou Shleib, Nadia M. El-Guink and Moustafa I. El-Ammori

Department of Pharmaceutical Microbiology, Faculty of Pharmacy, Alexandria University, Egypt.

Clinical isolates of Pseudomonas aeruginosa are often resistant to several common antibiotics including those anticipated as antipseudomonas. Although the antimicrobial combination of two antibiotics was more effective than the single agent, however in many instances, it was of limited effect. In this study, we propose a design for triple combination which is more promising. This design not only produced a more effective system, but also indicated the minimum effective limit of each component to give the maximum efficiency required. The design was tested using two triple combinations; the first system consisted of Amikacin (AK), Cefoperazone (CEF) and Ciprofloxacin (CIP), while the second system consisted of Bacitracin (B), Neomycin (N) and Polymyxin B (PB). Eight clinical strains of Ps. aeruginosa with different susceptibilities to the tested antibiotics were used for the combination studies. The results obtained using the developed checkerboard test were evaluated by the fractional MIC (FIC) index and were plotted on a triphase diagram. All the tested strains of Ps.aeruginosa were effectively inhibited and killed by the three - component combinations. In both tested systems, synergistic effect was obtained with all the tested isolates including the most resistant strains Ps3 and Ps4. For the most resistant strain, in the first system, the MICs for each antibiotic alone were AK: 25, CEF: 62.5, CIP: 1.6 µg/ml, these decreased to 1.56, 1.0, 0.2 µg/ml in the combination respectively. In the second system, the MIC for PB alone was 8 µg/ml, while B and N each alone had no inhibitory effect. However, the triple combination was most effective, and the MICs for B, N and PB in the combination were, 125, 125, 0.5 µg/ml respectively. The results showed a good correlation between the FIC index and the triangular diagram design. The principle and magnitude of the proposed design is discussed.

 

 

10/21 EFFICIENCY OF DETECTION OF MYCOBACTERIUM TUBERCULOSIS BY PCR ANALYSIS

Hassan A.M. Samaha

Department of Clinical Laboratory Sciences, Faculty of Applied Medical Sciences, Aljouf University, Saudi Arabia.

Resurgence of new M. tuberculosis epidemics, one decade ago, coupled with HIV complications prompted the initiatives for quick, sensitive and specific tests for detection of M. tuberculosis in clinical samples. One of these tests is polymerase chain reaction (PCR). This study is deemed necessary to evaluate the comparative diagnostic advantages of Polymerase Chain Reaction (PCR) test for confirmation of pulmonary tuberculosis with M. tuberculosis in clinical cases. Sputum specimens collected from 50 patients were investigated using Ziehl Neelsen (ZN) stain after digestion-decontamination and centrifugation. Decontaminated specimens were cultured on Lowenstien Jensen (LJ) medium for 8 weeks followed by biochemical identification of isolates. It was found that28/50 samples (56%) were positive for Acid Fast bacilli (AFB) with direct smear stained with Z.N. stain, whereas 34/50 samples (68%) gave mycobacterial growth on LJ medium showing sensitivity, specificity, positive predictive value (PPV) , and negative predictive value (NPV), 82.35%, 100%, 100%, and 72.72%, respectively, using LJ culture as a gold standard. On the other hand, 24/32 (75%) of clinical cases were PCR +ve LJ culture +ve, whereas 1/32 (3.125%) was PCR –ve LJ +ve making sensitivity, specificity, PPV, and NPV, 96%, 71.42%, 92.3%, 72.72%, respectively, using LJ as gold standard. Although PCR testing is a highly sensitive test for diagnosis of pulmonary TB, AFB smear method was superior in specificity and PPV with slightly lower than PCR in sensitivity. Since AFB smear is cheap, quick and not technically demanding, this should limit PCR to: 1) specific clinical cases as differentiation between M. tuberculosis complex and Mycobacterium avium complex (MAC) or other Mycobacterium other than tuberculosis (MOTT) in HIV patients, 2) precious samples such as those obtained with probably reduced positive culture.

 

11/21 ANTIBACTERIAL EFFECT OF HONEY AGAINST BACTERIA ISOLATED FROM BURN-WOUND INFECTIONS OF SOME PATIENTS IN AIN SHAMS UNIVERSITY HOSPITAL

Saadia M. Hassanein, Hassan M. Gebreel and Abdel-Rahman A. Hassan

Microbiology Department, Faculty of Sciences, Ain Shams University, Cairo, Egypt

Honey is an ancient remedy for the treatment of infected wounds. Four types of honey (Citurs, Clover, Nigella and eljabaly) were used. Six different species of bacteria were isolated from 120 burn- wound patients in Ain Shams University Hospital, namely Aeromonas schubertii, Haemophilius paraphrohaemlyticus, Micrococcus luteus, Cellulosimicrobium cellulans, Listonella anguillarum and Acinetobacter baumannii. A comparative study between the known groups of 18 antibiotics and honey was carried out to evaluate the importance of using honey in burn-wound treatment on the 6 isolated species and compared with the effect of different types of honey on the same becateria. It was found that eljabaly has strong inhibitory effect in comparison to other mentioned types. Concentration of 25% of eljablaly showed inhitbition of 4 types, whereas 30% was potent enough to destroy the 6 isolated bacteria. Data shown that its antibacterial activity was attributed to its high osmolarity and hypertonic sugar concentration and low PH values. Amino and fatty acids, total proteins patterns were significantly changed. Total lipids of bacterial species was sharply decreased.

 

 

12/21 GROWTH AND SURVIVAL OF MICROORGANISMS IN HEAT-TREATED MILK

Shabaan M.A. Taha and Samer A. Meleigy

Department of Microbiology, National Center for Radiation Research and Technology (NCRRT), Naser City, Cairo, Egypt

The effect of heating on microbiological quality of skim milk as well as growth and survival of pathogenic bacteria in raw and heat-treated milk were investigated. The raw skim milk samples contained the highest total bacterial count (TBC), total mold and yeast (TMY), lactic acid bacteria (LAB) and Enterobacteriaceae and contaminated with E. coli, Aeromonas hydrophila, Bacillus cereus, Staphylococcus aureus, and Enterococcus faecalis, and there was no detection of Listeria monocytogenes and Salmonella species. Pasteurization of skim milk reduced TBC, TMY and LAB and Enterobacteriaceae, E. coli, Aeromonas hydrophila, Bacellus cereus, Staphylococcus aureus, Enterococcus faecalis were undetectable. Boiling of skim milk reduced total bacterial counts about 4 log cycles, whereas the other microbial groups were reduced to undetectable levels. Autoclaving and ultra high temperature (UHT) of milk caused complete reduction of all microbial groups including pathogenic bacteria. Heat treatments caused a small decrease in the pH as compared with raw milk. Growth of different pathogenic bacteria in raw and heat-treated milk at 37oC caused markedly decrease in pH of skim milk rather than at 4oC. There was decrease in counts of A. hydrophila, E. coli and Staphylococcus aureus during growth in raw milk at 37oC or 4oC compared with other microorganisms. Growth of A. hydrophila, E. coli and Staphylococcus aureus in heat-treated milk at 37oC was reduced gradually with increasing temperature of heat treatments to undetectable level especially in UHT milk. These results also showed that Bacillus cereus,Enterococcus faecalis and Salmonella species grew better in heat-treated milk compared with other microorganisms.

 

 


13/21 PHENOTYPIC EVALUATION OF IMIPENEM AND MEROPENEM ACTIVITY AGAINST SOME GRAM-NEGATIVE MULTIRESISTANT CLINICAL ISOLATES

Nadia M. El-Guink

Department of Pharmaceutical Microbiology, Faculty of Pharmacy,

Alexandria University, Egypt

Carbapenems are important agents for the therapy of infectionsdue to multidrug-resistant Gram-negative bacilli. The development of carbapenem resistance due to metallo-beta-lactamases (MBLs) is an increasing problem all around the world, which poses the importance of the early identification of MBLs in clinical microbiology laboratories and the development of rapid, effective and easy methods for their detection.A total of 52 multi-resistant clinical isolates of Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa, with various MICs of imipenem (IPM) and meropenem (MEM) 0.0125 - >50 µg /ml were examined for the production of MBLs with different phenotypic laboratory tests. All isolates were evaluated by the double disc synergy test (DDST), the combined disc test (CDT), the modified Hodge test, and the modified three-dimensional test for detection of MBLs in cell extracts. Moreover, selected, representative isolates were also tested using the viable count technique. In the resistant isolates that exhibited MICs of IPM and MEM > 4 µg /ml, the CDT with IPM/IPM+0.1M EDTA or MEM/MEM+0.1M EDTA and the DDST with IPM or MEM 15 mm apart from 0.1M EDTA showed positive results for MBL production. In the modified three dimensional crude enzyme test, the resistant strains showed positive results for MBL production and gave antagonistic effects on the addition of 0.1M EDTA to the cell extracts. In the viable count technique addition of 0.25 or 1% EDTA to IPM or MEM highly increased the bactericidal activities of both carbapenems against the resistant strains by about 6 and 4 log in the number of survivors respectively. In conclusion, the CDT and the DDST together, and the modified three-dimensional test are effective methods for the routine detection of MBLs. Moreover, the viable count technique is a good objective confirmatory test. However, in this study, the modified Hodge test and the use of thiol-based compounds as mercaptoacetic acid (MAA) appeared to be inconvenient for the detection of MBLs in the laboratory, as they did not give encouraging results.

14/21 STATISTICAL EVALUATION OF ENVIRONMENTAL FACTORS LIMITING POLY(-e-CAPROLACTONE) NANOPARTICLE BIODEGRADATION IN SALINE HABITATS

Dunia-Manal M. Abou-Zeid, Eman H. Barakat and Soraya A. Sabry

Microbiology Division, Botany Department, Faculty of Science, Alexandria University, Egypt

Saline environments are important for surface extension and have ecological significance, but, as all other ecosystems, are impacted by pollution. Nevertheless, little information is available on the biodegradation of synthetic pollutants such as polyesters in such habitats. This is the first report on the elucidation of environmental factors limiting Poly-e-caprolactone (PCL) disintegration under salt stress. For this purpose and for the first time, PCL nanoparticle depolymerization was combined with a sequential optimization strategy based on statistical experimental design using a locally isolated halotolerant Aspergillus flavus Sw3 strain. The fungus was capable of growing on emulsified PCL as a sole carbon source and disintegrated the polyester as revealed by scanning electron microscopy (SEM) of commercialized PCL-S MATER Bi ZF03U films. A two-level Plackett–Burman multifactorial design was used to determine the impact of 11 variables on PCL nanoparticles degradation capabilities. Among the tested variables, an increase in NH4SO4-and a decrease in NaCl and polyester concentration were found to be the most significant. Indeed, a 3.2-fold increase in PCL depolymerase enzyme activity (15.04 IU mL-1) was recorded in the preoptimized medium compared to the basal condition settings. Subsequently, response surface methodology was applied to elucidate the level of the three significant factors affecting environmental PCL degradation. The Box–Behnken design identified nitrogen source (6.5-7.5 gL-1) and polyester availability (0.2-0.38 gL-1) as significant, as well as salt stress (20-40 gL-1) as a limiting factor for the production of the PCL depolymerizing enzyme. Under the optimized conditions, a 4.3 increase and hence a maximized PCL depolymerase activity of 20.2 IU mL-1 was recorded.

 

 

15/21 THE EFFECTIVITY OF PLANT GROWTH- PROMOTING RHIZOBACTERIA TO ENHANCE GROWTH OF LUPINE AND CHICKPEA

Maha A. Hewedy1, Abdel- Wahab, A.M2; El. Mokadem, M.T3 and El. Sayed, S.Y.4

1,3: Botany depart, Faculty of Women for Arts, Science and Education,

Ain Shams University.

2,4: Dept. of Agric. Microbiology, Soil, Water and Envrion. Res. Institute, ARC, Giza, Egypt.

Three rhizobacterial strains i.e., Serratia sp., Paenibacillus polymyxa and Pseudomonas flourescens were examined in vitro for achieving the traits that being related to plant growth promoting effects as well as, two pot experiments were carried out to study the impacts of rhizobacterial co-inoculation on growth of lupine or chickpea plants under sand soil conditions. Rhizobaterial strains were applied either singly or combined with nodulating Bradyhizobium (lupine) or Mesorhizobium (chickpea) plants or as mixed inoculants. The qualitative assay revealed that the tested PGPRs expressed variable magnitudes of PGP – related properties with superiority of P. polymyxa and Serratia sp. in IAA, siderophores, as well as P-solubilization. Inoculants which comprised Bradyrhizobium or Rhizobium with Serratia exhibited superiority for hastening all parameters under investigation.

16/21 PHYSIOLOGICAL AND GENETIC STUDIES ON THE ANTIMICROBIAL ACTIVITY OF SOME MEDICINAL PLANT EXTRACTS

Salama M. El Darier, Amani M.D. El Ahwany, Hoda H. Yusef and Aman A. Sorour

Botany Department, Faculty of Science, Alexandria University, Alexandria, Egypt

Agar diffusion method was used to determine the antibacterial activity of ethanolic extract of the three medicinal plants [(Carum copticum (Ajowan), Cetraria islandica (Iceland Moss) and Alpinia galangal (Galangal )] against seven bacterial species selected from different pathogenic groups. They were Agrobacterium tumefasciens, Erwinia sp, Klebsiella sp, E.coli, Proteus sp, Bacillus cereus and Bacillus thuringiensis. All of the three tested plants showed antimicrobial activity against all tested species. The most effective antimicrobial extract was that of Carum copticum. The presence of the Carum copticum extract in liquid culture medium, resulted in a sharp growth inhibition within the eight initial hours of bacterial growth. Intracellular bacterial proteins were examined on SDS gel electrophoresis. Growth of bacterial species in presence of Carum copticum extract in culture medium resulted in an additional protein bands which could be expressed as stress proteins only in response to adverse conditions. Transmission electron microscope clearly demonstrated that Carum copticum extract caused membrane damage and cytoplasmic coagulations. Plasmid curing led to a 5 fold increase in sensitivity of Agrobacterium tumefasciens to Carum copticum extract compared to the control.

 

17/21 RETROSPECTIVE STUDY ON TUBERCULOSIS AND HIV COINFECTION AMONG PATIENTS ADMITTED INTO TWO HEALTH CENTERS IN TRIPOLI- LIBYA

Fathi T. Al-Sabie, Vivek S. Agwan, Rasha A. Alghanimi and Nehal Y. Ghashoot

Department of Microbiology, Faculty of Pharmacy, Al-Fateh University for Medical Sciences, Tripoli -Libya.

In this study the data, concerning 60 human immunodeficiency virus (HIV) infected patients, who presented themselves at Tripoli Central Hospital and Libyan National Center for Infectious Diseases Prevention and Control, and 351 TB infected patients who presented at Libyan National Center for Infectious Diseases Prevention and Control, from 1 January 2007 to 30 December 2007, were collected and analyzed. The study included the results of detection of HIV in the serum of the patients, which was done by the use of quantitative polymerase chain reactions (QPCR), and the changes of CD4 and CD8, that were determined by ELISA technique. Also the results of the TB infected patients, which included tuberculin skin test, sputum microscopy for acid fast bacilli (AFB) and chest X-rays (CXR) for the suspected patients, beside the clinical symptoms. It was found that among a total of 60 HIV positive patients, 8 patients (13.3%) were also TB positive. Cases included more males (83.3%)   than females (16.7%). Positive history of intravenous (IV) drug abuse was number one risk factor with 32(53.3%) patients, sexual contact outside marriage 10(16.6%), dental extraction 6(10.0%), history of receiving blood and blood products and presence of HIV infected person in family 5(8.3%) each . No obvious risk factor was noticed in 2(3.5%) patients. Among a total of 351 TB infected cases, 59 patients (16.8%) were also HIV positive. The results showed that CD4 count increased and HIV- PCR quantity decreased by treatment among pure HIV patients more, than those coinfected with TB. The data of some blood parameters (hemoglobin %, WBC and platelets) more improved by treatment among HIV patients compared to those in HIV patients confected with TB.

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