The treatment of methicillin resistant Staphylococcus aureus (MRSA) infection is challenging
because of their high resistance to different antibiotics. The objectives of this study were to detect the
prevelance of S. aureus and MRSA carriage in ICU patients in Al Quwayiyah General Hospital and
to evaluate the performance of MRSA-Select agar media for rapid screening of MRSA Furthermore,
to describe the antibiotic susceptibility patterns of the S. aureus and MRSA isolates. During the
period from January to July 2018, a total of 278 patients admitted to the ICUs were screened for
MRSA. Culture of specimens was done on, MRSA-Select agar plate, Oxacillin Screen Agar BD
(Mueller-Hinton oxacillin agar screen plate containing4%Nacl and oxacillin 6mg/ml) and blood
agar. Suspected colonies of S. aureus were identified as by Gram stain, catalase, DNase, mannitol
fermentation, and coagulase positivity or by Vitek2 ID-GP card. All strains were tested with
Oxacillin disc diffusion method, Cefoxitin disc diffusion method, Latex agglutination test for
detection of PBP2a and Susceptibility testing of oxacillin-susceptible mecA-positive isolates by the
Vitek 2. The study showed that 56 (20.14%) isolates were MRSA, 45(16.18%) were MSSA,
164(58.99%) were CONS, 4 (1.44%) were Strept viridians, 2(0.71%) were gram negative bacteria, 3
(1.07%) were Corynebacterium spp., while 3 (1.07%) showed no growth. Antimicrobial
susceptibility results for the MSSA and MRSA isolates showed that all MRSA isolates were totally
resistant to β Ampicillin/sulbactam, Benzyle penicillin, Cefuroxime and Tetracycline while MSSA
isolates susceptibilities to same antibiotics were 75%, 60%, 98.7% and 75% respectively.
Susceptibility of MRSA to Quinupristin/dalfopristin, clindamycin, trimethoprim sulfamethoxazol,
erythromycin, streptomycin were 98%, 72.4%, 65.6%, 55.4% and 63.8% respectively, while MSSA
isolates showed more susceptibilities to same antibiotics which were 100%, 98.7%, 80.8%, 82.9 and
98.7% respectively. Both MRSA and MSSA isolates were 100% susceptible to levofloxacin,
linzolide, Tigecycline, vancomycin. the sensitivity and specificity of diagnostic methods for MRSA
by Oxacillin disc diffusion were 91.4% and 99.2% respectively, Cefoxitin disc diffusion were 98.5%
and 99.2%, MRSA -select agar were 99.2% and 98.4% respectively, Oxacillin Screen Agar were
97.1% and 100% respectively and Latex agglutination were 100% and 99.2%. Risks and infection
episodes due to Staph. aureus were significantly different between MRSA carriers versus MSSA
carriers and Colonization MRSA versus Other microorganisms. Total ICU acquired Staph. aureus
infection were occurred in 7.14% MRSA carriers, 3.05% MSSA carriers and 1.03% Other micro
organisms colonization. Conclusions: The prevalence of MRSA is high and rapidly increasing at Al
Quwayiyah General Hospital, as it is worldwide. Control measures to prevent the spread of MRSA in
hospital should continue with reinforcement of hygienic precautions and development of policies to
restrict the use of antibiotics. |
