Keywords : Biofilm


Comparison of Three Biofilm Detection Methods in Coagulase Negative Staphylococci Species

Ahmed Al-Jubory; Muhsin Ayoub Essa

Rafidain Journal of Science, 2021, Volume 30, Issue 2, Pages 1-15
DOI: 10.33899/rjs.2021.168342

This study was conducted with the aim of investigating the ability of Coagulase Negative Staphylococci (CoNS) for the detection of biofilms, which are considered as the main virulence factor in their pathogenicity. Three methods were used for this purpose, the tube method, congo red agar and tissue culture plate method. Thirty-seven isolates of the following bacteria were tested, which includes Staphylococcus epidermidis, S. saprophyticus, S. haemolyticus, S. hominis, S. lentus and S. sciuri.The results of the tube method showed that most isolates (64.5%) gave a moderate positive result, (32.3%) was weak positive and six isolates showed no ability to form biofilm, the congo red method showed that, the majority of isolates were a moderate positive result (89.3%) and nine isolates were negative for biofilm formation. As for the tissue culture plate method, the results ranged between (62.9%) a moderate positive and (31.4%) a weak positive, while only two isolates could not form biofilm. When comparing the efficiency of the three methods in detecting the ability of CoNS isolates to form biofilm, it was found that tissue culture plate method was the most efficient (94.6%), followed by the tube method (83.8%), and the congo red (75.7%).

Investigation of the Ability of some Bacteria Isolated from Intravenous Catheters to form Biofilms and the Effectiveness Ability of some Substances in Removing them

Raad M. Mahmmod; Amera M. Al-Rawi

Rafidain Journal of Science, 2020, Volume 29, Issue 3, Pages 14-26
DOI: 10.33899/rjs.2020.166315

The research included investigating some of the contaminated bacteria of the Cervical Vein Catheter (CVC) devices in patients with dialysis in  Ibn Sina Teaching Hospital (alternative site), then testing the ability of the isolated bacteria to form the biofilms in two ways, the  congo red agar and the tube method, as well as evaluating the effectiveness of some substances to remove the biofilms                       
   The results showed that the contaminated bacteria of the cervical venous catheter apparatus included: Staphylococcus aureus, Staphylococcus haemolyticus and Burkholderia cepacia. The current study also showed that the ability of the pathogenic bacteria above to form the biofilms by Tube Method came at 3,2 and 0, bacteria respectively, and its ability to the composition of the biofilms by the Congo Red Agar Method came at 2,2 and 0, bacteria respectively. The results also showed the high ability of Vancomycin and Meropemen 10% for each one, and Alum 20% as well as natural lemon juice undiluted to remove the biofims formed by the Staphylococcus aureus bacterium. As for the other materials that were used, they did not show any ability to remove the biofilms.                                                                                                

Contamination of Domestic Well Water in Nineveh Governorate with some Pathogenic Bacteria and Detection on its Ability to Biofilm Formation

Amera M. Al-Rawi; Manar F. Altaee

Rafidain Journal of Science, 2019, Volume 28, Issue 3, Pages 90-104
DOI: 10.33899/rjs.2019.163162

Due to the unavailability of the drinking water in Mosul city in the period between                      (2014-2017), people started digging wells in their houses to use it in daily life for consumption and irrigation. Forty well water samples were chosen for this study in living quarters (AL-Dubat, Adan, AL-Mouthana, AL-Noor, AL-Zhoor, AL-Jamiea, AL-Falah, AL-Baker). Some pathogenic bacteria were isolated and identified from well water digged in different areas in the left side of Mosul city and to study reconciliation to human consumption. Results showed that fifty-six bacterial isolates obtained included 21 of Escherichia coli, 10 of Aeromonas hydrophila, 8 of Pseudomonas aeroginosa, 7 of Pseudomonas florescens, and show two species ofKlebsiellabacteria, Klebsiella pneumonia and Klebsiella oxytoca 6 and 4 respectively.
Then the ability of these bacterial isolates to form biofilm was studied by using two methods; Tube method and Congo red method, isolates gave 100% positive results in its ability to biofilm formation by tube method. While by congo red Aeromonas and Pseudomons were unable to form biofilm.
Also the study included determination of antibiotic  sensitivity and resistance of bacterial isolates to different antibiotics as it is considered one of the important virulence factors , Results showed that there is variation in its sensitivity and resistance to these antibiotics.

The Effect of some Variables on the Quantity of Exopolysaccharide Produced by Klebsiella pneumoniae

Sumaya A. Al- Hamdoni

Rafidain Journal of Science, 2018, Volume 27, Issue 2, Pages 47-57
DOI: 10.33899/rjs.2018.145390

The current study attempted to compare the production of exopolysaccharide (EPS) by a clinical isolate Klebsiella pneumoniae under different selected conditions using the colorimetric method, phenol-sulfuric acid. The results revealed that the chemically defined medium was the most efficient for the production of free bacterial exopolysaccharide. The type and concentration of carbon source were of critical role in determining the amount of the yield EPS. The elevated fructose concentration furnished the highest level while lactose promoted the lowest yield. The pH ranges between 6- 8 of the medium promote the maximum production; lower and higher than this range the production will decrease. In the batch culture vessel used in the current study, a bacterium inoculum of 3-5% (v/v) produced a valuable amount of EPS after three days of incubation