Publication List for Department of Microbiology & Parasitology

Publication statistics for Department of Microbiology & Parasitology

  • Icon missing? Request it here.
  • 4

    Conference paper

  • 19

    Journal Article

  • 0


  • 0


  • 0

    PhD Thesis

  • 3

    Master Thesis

  • 0

    Final Year Project

  • 0

    Technical Report

  • 0

    Unpublished work

  • 0


Antimicrobial Sensitivity Patterns of Pseudomonas aeruginosa Isolates Obtained From Foot Ulcer Diabetes Patients in Tripoli, Libya.

Background: Pseudomonas aeruginosa is one of the most invasive organism that causes severe tissue damage in diabetic foot ulcers. A major problem in P. aeruginosa infection because of that it is commonly exhibits a high degree of resistance to antimicrobial agents .To improve appropriate antimicrobial therapy and reduce the incidence of antibiotics resistant bacteria, information on the antibiotic susceptibility to this bacterium is urgently needed. Therefore, the aim of this study was to isolate and determinate the antimicrobial susceptibility of the P. aeruginosa in diabetic foot ulcers patients. Methods: This study was carried out over the period between June 2014 to April 2015 at Tripoli Medical Center. A total of 120 bacterial isolates were cultured onto bacteriological media such as nutrient agar, MacConkey agar and blood agar. Identification of retrieved bacterial isolates was done using standard diagnostic microbiological laboratory methods and antibiogram was determined by VITEK ® 2 compact automated system. Results: Twenty one strains of P. aeruginosa from 120 diabetic foot ulcers were detected. P. aeruginosa isolates exhibited multidrug resistance to Ampicillin, Augmenting, Cefuroxime, Cefoxitin, Cefazolin, Ceftriaxone, Trimethoprim/sulfamethzole, Piperacillin. However, all isolates of P. aeruginosa were 100 % sensitive to Imipenem. Conclusion: P. aeruginosa infections of diabetic foot ulcers patients have multi-drug resistant. Imipenem is the empirical antibiotic of the choice. Key words: Pseudomonas aeruginosa, diabetic foot ulcer, antibiotics resistance arabic 17 English 114
Abdulkareem Elbaz, Abdulkareem Elbaz, Abdulgader Dhawi, Asma K. Elramalli, Ibrahim A. Algondi, , , Mustafa Saieh(12-2018)

Salmonella Enteritidis’ Proteins produce in Vitro and in Vivo Protection against Colonization

Salmonella enterica can be considered as one of the most important causes of foodpoisoning with poultry thought to be the main source. Although S. Typhimurium, S. Enteritidis and the vast majority of other Salmonella serovars generally produce little systemic disease in adult chickens, they are able to colonize the alimentary tract of poultry. The two caeca are the main sites of the colonization of Salmonellae in chickens, and the bacteria can be easily harvested from the caeca for analysis. Bacterial proteins analysed utilizing SDS-PAGE showed differences between in vitro and in vivo that out of about 40 protein bands of in vitro preparation only a few (3-5) bands can be visualized from in vivo preparations. We suggested that some avian proteases might be responsible. Accordingly, and to investigate the hypothesis that bacterial-precipitated protein harvested from chickens is thought to be more protective than bacteria grown in broth culture, the immunogenicity of protein-precipitated vaccines harvested from chicken intestine and those from broth culture (in vitro), were compared using bacterial proteins as an orally inoculated vaccine candidate in chicken. The results demonstrated that the in vitro sonicated proteins obtained from a nutrient broth culture had a much better protective vaccine effect than the in vivo sonicated proteins preparations harvested from bacteria grown in chickens arabic 14 English 81
Altayeb Elazomi, Elhadi Araibi, Abdulgader Dhawi, Hatem Khpiza, Susan Liddell, Margret Lovell, Paul Barrow(12-2016)

Identification of phenolic compounds, antibacterial and antioxidant activities of raisin extracts

In this study, antibacterial, antioxidant and phenolic compounds of raisin extracts was evaluated. Different solvent extraction methods were utilized to extract phenolic compounds from raisin. The phenolic compounds of raisin extracts was determined using HPLC and three compounds were found, catechin, quercetin and rutin. The antibacterial activity of the acetonic extract was tested against four bacterial pathogens viz. Staphylococcus aureus, Pseudomonas aeroginosa, Salmonella typhimurium and Escherichia coli using both disk diffusion and minimum inhibitory concentration (MIC) methods. The acetonic extract exhibited the highest activity against Staphylococcus aureus with zone of inhibition of 14mm and the MIC of 25 mg/ml. However, there was a little activity against E. coli and S. typhimurium. The methanolic extract showed good antioxidant activity as indicated by 2,2-diphenyl-1-picrylhydrazyl free radical assay (DPPH). In conclusion, raisin contains potent phenolic compounds and their application might function as promising natural preservative and antimicrobial agents in food industry and also good antioxidant food that helps to minimize the risk of degenerative diseases. arabic 11 English 86
Abdulgader Dhawi Alfitouri Dhawi(1-2021)

A Study of Bacterial Contamination on Libyan Paper Banknotes in Circulation

Paper currency is one of the potential vectors to transmit diseases, since banknotes continuously pass through different hands, as a medium of exchange, which increases the possibility of transferring pathogenic microorganisms and thus cross contamination. This study was carried out on one hundred and ninety-eight paper currency notes that were collected randomly in the city of Tripoli, Libya, from different communities namely, petrol and gas stations, supermarkets, mini markets, cafeterias and fast food restaurants, etc. The samples consist of four pieces, each of currency (Dirham) denominations (250, 500, 1.000 and 5.000 notes). Conventional and current microbiological techniques were used in order to isolate and identify the species of microorganisms that resulted in the following percentages: Enterobacter agglomerans 19%, Pseudomonas spp. 16%, S. aureus, Enterobacter cloacae 11%, Klebsiella pneumonia 11% and E. coli 10%. These results indicate that Libyan banknotes are commonly contaminated with pathogenic bacteria, which have the possibility of spreading human diseases. Higher denomination currency showed lower contamination. Consequently, great care should be taken during the handling of money for the safety of human health. arabic 10 English 65
Abdulgader Dhawi Alfitouri Dhawi(1-2021)

Bovine digital dermatitis and severe virulent ovine foot rot: a common spirochaetal pathogenesis

A potential pathological role for spirochaetes in bovine digital dermatitis (bovine DD) and severe virulent ovine foot rot (SVOFR) has been considered and a treponeme isolate obtained from each disease in the UK. In this work, we have investigated the hypothesis that the two diseases may have a shared (common) spirochaetal aetiology. Experiments were designed to identify serological similarities and differences between the two spirochaetes; an enzyme-linked immunosorbent assay (ELISA) was developed to detect anti-treponeme antibodies in the sera of cows and sheep against the two-treponeme isolates. Sera were further tested for antigen reactivity by Western blotting. Cattle and sheep with bovine DD and SVOFR, respectively, had increased seropositivity rates to both treponeme isolates, with different patterns of reactivity between farms. In some cattle herds, significant correlations were shown between antibodies to bovine DD treponemes and SVOFR treponemes (P0.05); sheep showed strong evidence of reactivity to one or the other treponeme antigens, but never to both. Western blotting against both treponeme antigens showed that they frequently displayed different antigen epitopes, although some minor bands were common to both organisms. The data suggest that there are a number of spirochaetes in UK farms, which could be involved in the pathogenesis of either bovine DD or SVOFR. arabic 13 English 83
Abdulgader Dhawi Alfitouri Dhawi(1-2021)

Characterization of a spirochaete isolated from a case ofbovine digital dermatitis

Aims: The aim of the study was to characterize a spirochaete isolated from thelesions of a cow with digital dermatitis (DD).Methods and Results: The characterization was on the basis of its light andelectron microscopic appearance, enzymic profile and DNA sequence analysisof its flagellin and 16S rRNA genes. The spirochaete was 6–8-lm long and 0Æ2–0Æ3 lm in diameter, and possessed seven to eight periplasmic flagella, withthree to five helical turns. The enzymic profile of the bacterium resembles, butis not identical to that of Treponema brennaborense. Its flagellin gene sequencewas identical to that of Treponema phagedenis but distinct from that of anovine spirochaete. Analysis of a 1477-bp region of the 16S rRNA genes indica-ted that this is a Treponema species and that it is indistinguishable from someisolates made from cases of bovine DD in the United States. Finally, electronmicroscopy revealed the presence of myovirus-like bacteriophage particles in allcultures of the treponeme examined.Conclusions: The spirochaete isolate was identified as a Treponema species clo-sely related to some isolates from the United States (by 16S rDNA) and to T.phagedenis (by flagellin gene sequence) and is associated with bacteriophageparticles.Significance and Impact of the Study: The fact that the isolates with the sameor very similar 16S rDNA sequences have been obtained from cases of bovineDD in cattle in different countries at different times, lends further support tothe hypothesis that treponemes play a role in the pathogenesis of this disease arabic 10 English 72
Abdulgader Dhawi Alfitouri Dhawi(1-2021)

Adaptation to the chicken intestine in Salmonella Enteritidis PT4 studied by transcriptional analysis

The transcriptional changes that occurred in Salmonella enterica serovar Enteritidis during colonization of the alimentary tract of newly hatched chickens were studied. A whole genome oligonucleotide microarray was used to compare the expression pattern with that from bacteria cultured in nutrient broth in vitro. Amongst other changes Salmonella Pathogenicity Island (SPI)-1, SPI-2 and SPI-5 genes were up-regulated in vivo suggesting a close association with the mucosa during colonization. Particular attention was paid to genes associated with metabolism of dicarboxylic acids and to responses to high osmolarity. Association between the colonization phenotype and gene mutations indicated that the latter was more important as a contribution to the colonization phenotype. arabic 12 English 89
Abdulgader Dhawi, Elazomi A, Jones M A, Lovell M A, Li H, Emes R D, Barrow P A(7-2011)
View publisher's website

Characterization of methicillin-resistant Staphylococcus aureus isolated at Tripoli Medical Center, Libya, between 2008 and 2014

Bacterial pathogens such as methicillin-resistant Staphylococcus aureus (MRSA) represent a well-known public health problem affecting both healthcare-associated and community populations. Past studies have clearly shown the value of characterizing problem organisms including MRSA through the use of molecular techniques (i.e. strain typing), with the aim of informing local, regional and national efforts in epidemiological analysis and infection control. The country of Libya represents a challenge for such analysis due to limited historical infectious disease information and major political unrest culminating in the Libyan Civil War (Libyan Revolution) in 2011. A MRSA study population of 202 isolates, cultured from patients in Tripoli Medical Center through this historical period (2008–2014), was characterized by both phenotypic and molecular methods. The results revealed a diversification of epidemic MRSA strains over time with generally increasing resistance to fluoroquinolone antibiotics. The study identified prevalent MRSA in comparison to known global epidemic types, providing unique insight into the change of strains and/or characteristics over time especially with reference to the potential influence of the political revolution (i.e. pre- and post-2011). arabic 17 English 111
Elloulu BenDarif, Asma Khalil , Abdunnabi Rayes , Emad Bennour , Abdulgader Dhawi, John J Lowe , Shawn Gibbs, Richard V Goering (12-2016)
publisher's website