Purpose:
To compare antibiotic susceptibility patterns of conjunctival bacterial flora isolated from patients with and without chronic blepharoconjunctivitis (CBC).
Methods:
Patients with CBC (n = 60) and without CBC (n = 40) were enrolled after approval by the local Ethics Committee. Conjunctival cultures were obtained from both eyes by rotation of a swab moistened in thioglycolate through the inferior fornix from the nasal to the temporal side, covering all sides of the swab and inoculated into thioglycolate broth for bacterial growth. Identification of organisms and antibiotic susceptibility testing were performed with the Vitek 2 system (bioMerieux®).
Results:
Fifty-two patients with CBC completed the study and had a significantly higher rate of positive thioglycolate broth cultures (94%) compared to a 58% positive culture rate in 40 patients without CBC (P < 0.0001). Among the 142 bacteria isolated the most common were coagulase-negative Staphylococcus (CNS) in 81,8% (n = 36 of total 44 isolates) in patients without CBC and 69,4% (n = 68 of total 98 isolates) in patients with CBC. The rates of antibiotic resistance for CNS in the group with CBC were high to the penicillins (82.4%), mezlocillin (60.3%), ciprofloxacin (22.1%), norfloxacin and ofloxacin (20.6%) and levofloxacin (17.7%). In the group without CBC resistance rates were as follows: the penicillins (69.4%), mezlocilin (27.8%), ciprofloxacin (11.1%), norfloxacin, ofloxacin and levofloxacin with (13.9%). In both groups CNS were relatively more sensitive to the cephalosporins, carbapenems, aminoglycoside, gatifloxacin, moxifloxacin and vancomycin.
Conclusions:
Chronic blepharoconjunctivitis eyes have a significantly higher number of positive cultures and rate of antibiotic resistance of isolated Coagulase negative Staphylococcus compared to eyes without CBC. Therefore, patients with chronic blepharoconjunctivitis might benefit from a course of topical antibiotic prior to surgery to reduce conjunctival bacterial load.
Keywords: clinical research methodology • conjunctiva • microbial pathogenesis: clinical studies