Investigating the effect of some physical and nutritional factors on Klebsiella pneumoniae biofilm formation

One hundred clinical samples were collected from different pathological conditions. After the final diagnosis, 50 clinical bacterial isolates belonging to Klebsiella pneumoniae were obtained by 50%, and the percentage of isolates obtained from sputum was 23 (46%), urine 22 (44%), feces 2 (4%), and tracheal pus 3 (6%). The isolates were cultured and diagnosed in the conventional ways, and for the final diagnosis and antibiotic sensitivity test (AST), the Vitek2 system was used. All isolates of K.pneumoniae were highly resistant to antibiotics: 92% against cefepime, ceftazidime, ciprofloxacin, levofloxacin, and ceftriaxone; 72% against imipenem and meropenem; 68% against trimethoprim/sulfamethoxazole; 60% against tobramycin; 56% against gentamicin; and 44% against amikacin and 36%, while it was highly sensitive to 96% for each of piperacillin, ticarcillin/clavulanic acid, and Piperacillin/Tazobactam were 96%. The results of the study showed the ability of K. pneumoniae isolates to form biofilms using the 100% Microtiter Plate method but in varying formations. 26 isolates (52%), 15 isolates (30%), and 9 isolates (18%) showed strong, medium, and weak abilities respectively. Glucose, lactose, and yeast extract were among the best nutrients affecting the increase of biofilm formation. On the other hand, the temperature at 37°C and 25°C and the pH at 7, 8, and 9 had a positive effect on the production of biofilms.