Prevalence of Staphylococci Among Dental Staff and Their Antibiotic Resistance Pattern.

,


2-Identification of Staphylococci:
The

RESULTS AND DISCUSSION
carried on DNA fragment known as the Staphylococcal cassette mec ( SCCmec ), which encodes the pencillin binding protein -2a (PBP-2a) that inhibits the action of βlactam antibiotics[6], so PBP2 continues in cell wall synthesis even in the presence of high concentration of βlactam antibiotics; also MRSA produce a βlactamase enzyme which damage the functional perfection of βlactam antibiotics by spliting the βlactam ring of pencillin molecules [9] which enable them to cause particular clinical syndroms [10].In addition to their antibacterial resistance, MRSA strains are able to produce biofilm: a dynamic and complex multi-layer cellular matrix which is considered to be a major virulence factor [11], once biofilm was formed, the eradication of Staphylococcal infection in patient become very difficult, in addition, biofilm promotes the horizontal spread of antibiotic-resistant determinants [12].The source of MRSA infection in dental clinics could be infected or colonized patients, dentists and environmental surfaces, air and water syringes, dental chair, pushbuttons, light handles [13].Resistance of S.aureus to antimicrobial agents can take place by intrinsic or acquired resistance, the emergence of multi-drug resistance may indicate the presence of efflux pumps which contributes to the antimicrobial resistance of many bacteria [14].The study aims to estimate the carriage of Staphylococci spp on nares and hands among dental staff and their antibiotic resistance pattern.
include swabs from noses and hands of the dental workers (dentists and assistants) in the dental teaching hospital -University of Mosul, samples were collected for the period of 17 th Dec. 2020 to 9 th Feb. 2021 by using a sterile cotton swab; 200 samples were collected (100f rom nose) and (100 from hands) , transferred to the laboratory inside vial contains Nutrient broth [8] [15].From (n=100) dental staff (dentists = 96, and assistants = 4);they were ( males 61 ; female 39), their ages ranged between(17-50) years ;100 swabs from nose and 100 swabs from hands were taken.

Table 3 -
sensitivity of Staphylococcal isolates to oxacillin using minimum inhibitory concentration (MIC) using Vitek-2

Table 4 -
Result of sensitivity testing of samples using Kirby -Bauer method.Staph.Aureus is the most isolated bacteria in our samples than other bacteria, especially in nose samples.An obvious level of resistance was exhibited against βlactam antibiotics.the