Abstract

INHIBITION OF Acinetobacter baumannii ADHESION BY ANTI-FIMBRIAL ANTIBODY: THE FIMBRIAL ANTIGEN EFFECTIVENESS

Author(s): Hadeel K. Musafer*,Rajwa H. Essa

Objective:Collecting samples of Acinetobacter baumanniitaken from different clinical cases of wounds, septicemia, and urinary tract infections. That was accomplishedby taking  (296)  samples  from  Baghdad  educational hospital and  Ibn-al-Baladi hospital.  Samples  were  cultured  on  solid media  (McConkey  and  blood  agars),  and  according  to microscopical, cultural, and biochemical identification, in addition to using API 20-E system, (21) isolates of A. baumanniiwere identified and in percentage of 47.619, 9.523, 14.285, and 28.571 for wound, blood, sputum, and urine samples, respectively. Methods:detection of fimbriated bacterial isolates among 21 isolates, and all those isolated were  fimbriae  forming  isolates;  isolate  number  (9)  was  selected  as  an  effective  isolate  in  formation  of  fimbriae.  Non-forming  fimbriae  isolate  of  Shigella  flexneri  is  used  as negative  control. Results  and  Conclusion:the  average  of  adherence  of  fimbriated  bacterial  cell  with  human  epithelial  cells  was  reached  (50)  adherent  bacterial  cell  per epithelial cell  compared  with  the  average  of  adherence of  control isolate  (12)  adherent  bacterial cell  per  epithelial cell,  the inhibition processes  are performed:  Inhibition  of bacterial  adherence  by  specific  antibodies  of  fimbriae  antigen  showed  inhibition  effect  of  adherence  in  respect  to  fimbriatedisolate A.  baumannii9  also  the  subminimum inhibitory  concentration  for  four  antibiotics  (Gentamicin,  Tobramycin, Cefepime,  and  Amikacin)  inhibit  the  adherence  of  fimbriated  isolate.  The  isolates  (used  in  the  study) have the ability to agglutinate Saccharomyces cerevisiae and human red blood corpuscles (RBCs). The study of effect of different fimbriae extract concentrations (25, 50, 100 μg/ml)  on  immune  cells;  consequently,  reached  to  the  following  results:  Concentrations  of  (25,  50,  100)  μg/ml  showed  a  negative  effect  on  lymphocyte  and  PMNs  viability which  increased  significantly  (P≤0.05)  with  increasing  of  fimbriae  extract  concentration.  On  the  other  hand,  concentrations  of  (25,  50)  μg/ml  of  fimbriae  extract  caused  a significant increase (P≤0.05) noticed in the average of T-cells forming the active T-Rosette (41.3, 54.3)% and the total (62, 81)% compared with control which reached (28.3, 40.6)% respectively. The present study results revealed an increase in phagocytosis of killed yeast cells by phagocytes. To our knowledge this is the first preliminary report in Iraq  showed  the  role  of  fimbriated A. baumanniiin  adherence  on  epithelial  cell  and  inhibition  of  this  adhesion  by  specific  antibody,  also  this  report  investigated  the  role  of fimbrial antigen on some immune cell.

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