One hundred and fifty isolates were isolated and identified from patients with urinary tract infection, and they were belonged to five genera: E. coli 70 isolates (46.7%), Klebsiella 20 isolates (13.3%) [in which 18 isolates were Klebsiella pneumonia and 2 isolates were Klebsiella oxytoca], Proteus 18 isolates (12%), Enterobacter 13 isolates (8.7%), Pseudomonas 12 isolates (8.0%) and Staphylococcus 17 (11.3%) isolates [in which Staphylococcus epidermides 9 isolates and Staphylococcus aureus 8 isolates]. Ninety isolates (60%) were obtained from female while sixty isolates (40%) from male.
The antibiotic sensitivity pattern was examined for all (20) Klebsiella isolates and results showed that all the isolates (100%) were resistance to penicillin, 16 isolates (80%) were resistance to ampicillin and streptomycin 15, isolate (75%) were resistance to gentamicin and, 14 isolates (70%) were resistance to chloramphenicol, while all the isolates (100%) were sensitive to imipenem, and 14 isolates (70%) were sensitive to norfloxacin, 13 isolates (65%) were sensitive to cephalexin, 12 isolates (60%) were sensitive to tetracycline and cefotaxime and 11 isolates (55%) were sensitive to aztreonam.
A number of virulence factors of Klebsiella were detected, results showed that all the isolates (100%) were encapsulated, having colonization factor antigen type I (CFA / I), while 16 isolates (80%) were have colonization factor antigen type III (CFA / III). All the isolate (100%) were able to produce siderophore, while none of them were able to produce hemolysin.
Results showed that 75% of Klebsiella isolates were resistance to the serum bactericidal effect, while 25% of the isolates were sensitive. Also, all the isolates (100%) showed the ability to adhering to epithelial cells. However, MR1, MR2, MR10 and MR16 isolates had the highest level of adherence with an average of 20 bacteria per epithelial cell. All the isolates showed high resistance to the phagocytosis in which the phagocytosis percentage was decreased for all isolates and it was ranged between 7.5-15.0%.
To study the relationship between plasmids of Klebsiella pneumoniae MR1 and its pathogenicity, bacteria was treated with ethidium bromide. Results showed that there was a number of cured isolates which lost resistance for many antibiotics. Chloramphenicol and aztreonam resistance markers in this bacterium were carried on two different plasmids, while ampicillin and tetracycline resistance markers were carried on one plasmid. And the streptomycin and gentamicin resistance markers were carried either on chromosome or on mega plasmid which can not be cured.
The cured isolates MR1C1 and MR1C2 (which lost resistance to ampicillin, tetracycline, chloramphenicol and aztreonam) were choused to be tested for other virulence factors. Results showed that both isolates were capsulated but the capsule size was reduced, also both isolates were still have the ability to produce colonization factor antigen type I and III (CFA / I and III) and the ability to produce siderophores. However, resistance to serum bactericidal effect was decreased compared to MR1 isolate, and adherence ability of these two cured isolates was decreased in which the average of adherence cells became 2-7 bacterial cells / epithelial cell, also phagocytosis resistance was decreased in which phagocytosis percentage reached to 53% and 60% for the MR1C1 and MR1C2 respectively.
From these results it was concluded that genes encoding for the colonization factor antigen (CFA I / III) and siderophore production of Klebsiella pneumoniae MR1 are carried on chromosome, while gene encoding for capsule synthesis was carried on chromosome and regulated by plasmid gene (s). The changes in other properties (resistance to serum bactericidal effect, adhesion ability and phagocytosis resistance) may be due to the capsule reduction.
