Abstract

EVALUATION OF GENOTYPE AND PHENOTYPE METHODS FOR DETECTION OF BIOFILM FORMED BY STAPHYLOCOCCUS EPIDERMIDIS ISOLATED FROM PATIENTS IN SOME HOSPITALS OF BAGHDAD CITY

Nihad Khalawe Tektook*, Rajwa Hassen Essa, Susan Saadi Hussein

Abstract

Coagulase-negative staphylococci have important role as pathogen andmost common cause of bacteremia related to indwelling device, S.epidermidis was the most frequently isolated species in blood culturesand most important of the skin flora, it can cause severe infections afterpenetrates anatomic barriers, because it produces various proteases,peptidases, surface lipoproteins that promote host tissue adherence andbiofilms. The research included isolated 50 S. epidermidis strains fromclinical specimen (60% blood culture , 22% catheters urine , 12%wound and burn swab as well as 6% skin and nasal swab from hospitalstaff.) from 480 patients at ( Imam Ali ,Al-Kendy, Al-wasety, Ibn-Albalade and Baghdad )Hospital, In a period of study ( February to July 2014) .Identified and diagnostic thesebacteria by APi 20, VIETK 2 system, as well as classical method. Slime producing whichdetected by three phenotyping methods 60% of bacterial isolate were positive biofilmproduced by microtiter plate, while ( 38, 16)% respectively were positive for both tube andCRA methods. While (34,20,10,2)% of the S. epidermidis isolates from blood culture, urinecatheters, wound and burn swab as well as swab of Skin and nasal hospital staff producedbiofilm phenotypically.The results indicated that the IcaA gene had the highest rate in bloodculture (34 %) and Catheter urine specimen (20%) followed by IcaD gene which wasdetected in 38 % of blood culture and 20% of Catheter urine specimen. The prevalence ofIcaA gene (66%) was low versus that of IcaD gene (72%). 27, 28 strain ofstaph.epidermidis were biofilm-positive for Ica A and Ica D respectively by Mtp while 15strain were positive to both IcaA and IcaD by tube methods. Most positive both genotype (Ica A, Ica D) and biofilm produced Were 28(56%) while negative for both of them and negative biofilm produced were 13(26%), While 5(10%) were positive for Ica A / D and negative for phenotype (biofilm produce). In relation of S.epidermidis, 66% (29/50) of clinical strain present Ica genes and slime producing. While four only out of 50 clinical strain are producing slime but losing the Ica genes also 26% (13/50) of clinical strain were non-slime producing and Ica genes were negative.

Keywords: Staph. Epidermidis, biofilms, Ica(Intercellular adhesion).