Biofilm formation and the presence of intercellular adhesion locus "ica" among staphylococcal from catheter associated infections

Catheter infections are most commonly caused by staphylococci, either coagulase negative [CONS] or Staphylococcal aureus [S. aureus]. It has been established that clinical isolates often produce a biofilm, which is involved in adherence to biomaterials and provides enhanced resistance of bacteria against host defences and antibiotic treatment. This study aims to detect the biofilm forming ability of staphylococcal clinical isolates evaluated by Congo red agar plate test [CRA] and spectrophotometer, and to determine the occurrence of the of the icaA and icaD genes for biofilm production by PCR. This study included 50 staphylococcal strains 26 [52%] CONS and 24 [48%] S. aureus isolated from urine catheters, central venous catheters, peripheral venous catheters, collected from 137 catheterized patients attending neonatal, internal medicine and surgical intensive care units [ICUs] and 20 strains, [10 [50%] CONS, 10 [50%]] S. aureus] isolated from skin and nasal swabs collected from 40 healthy volunteers as a control group. The results showed that according to CRA, 14 [53%] CONS and 18 [75%] S. aureus strains were biofilm producers. While quantitative detection showed that 10 [38.4%] CONS and 14 [58.3%]S. aureus were strong biofilm forming, 2 [7.6%] CONS and 4 [16.6%] S. aureus strains were weak biofilm producers, and all strains of control group were non biofilm forming. Both icaA and icaD genes were present in 17 [65.5%] CONS and 19 [79.1%] S. aureus strains, [6 strains were PCR positive and negative with the other two tests] and absent in all strains of the control group. We concluded that CRA, spectrophotometer and PCR are all valid tests and we can use any of them in the diagnosis of catheter associated biofilm formation, the choice depends on the health condition of the patient, PCR is a rapid tool for diagnosis especially because a large number of catheterized patients are critically ill and rapid diagnosis is required

Evaluation of immunologic tests in the diagnosis of allergic rhinitis

Inhalant allergens are most frequently involved in allergic rhinitis. IgE antibodies bind to mast cells. Degranulation of those sensitized mast cells release mediators which are responsible for allergic rhinitis. In this work, serum samples of 45 patients, as well as serum samples of 15 control, were studied for total IgE concentration. Antibodies specific to a group of allergens are tested by Phadia Top procedure as well as Phadezyme RAST procedure which utilizes single specific allergen in each disc to specify accurately the causative allergen. Total IgE concentration ranged from 2-110 UK/L in controls [15 cases] and ranged from 18-900 UK/L in patients [45 cases]. 29 patients had IgE concentration> 110 UK/L, 15% of them were positive by Phadia Top test while 24% were positive by Phadezyme RAST test

role of Hepatitis C Virus infection in hepato-cellular carcinoma

The prevalence of antibodies to hepatitis [C] virus [anti-MCV] has been studied using HCV EIA, 2nd generation test in 20 cases of chronic liver disease [CLD], 20 cases of high risk of infection [blood donors and haemodialysis patients] and 10 healthy persons as a control group. All cases were tested for hepatitis [B] virus [HBV] markers as well as tumour markers. Anti-HCV positivity was found in 55% of cases of the CLD group, in 15% of haemodialysis patients and in 10% of the control group. Tumour markers were positive only in 35% of CLD group, who were also positive for anti-HCV. Our study revealed that HCV plays a more important role than HBV in causation of chronic liver disease and hepatocellular carcinoma. Blood transfusion and haemodialysis proved their importance in acquisition of HCV infection

Molecular analysis of virulence plasmids of invasive shigella species

A total of 48 isolates of Shigella species obtained from the Military Central Laboratories was examined for serotype, antibiotic resistance and invasiveness. The transferability and molecular structure of the virulence plasmids from each isolate were also examined. Twenty strains were evasive and 70% of these virulent strains were multidrug resistant. Ten virulent strains [tra+] transferred ampicillin resistance and virulence simultaneously, i.e. they carried conjugative plasmids; while the other strains [10 strains] were tra-. By plasmid analysis and DNA homology, almost all the virulent strains carried a large plasmid of 230 Kb, and 2-3 small cryptic plasmids [6.4, 3.3 and 2.7 Kb]. The results suggested that the cryptic plasmids can be transferred to other strains of the same species by conjugation or mobilization, predicting that the virulent multidrug resistant strains may no longer be restricted to a narrow range of serotypes in the near future. Further genetic analysis of virulence plasmids may be essential for the development of recombinant vaccines against Shigella species