Heamolytic activities, deoxyribonuclease production and in-vitro flouroquinolones susceptibility profile of aerobic gram positive cocci associated with acne vulgaris

Abstract

Bacteriological investigations were carried out on forty–six (46) swabbed samples from the pustular and nodulocystic skin lesions of undergraduate students with acne vulgaris using standard bacteriological methods. The fluoroquinolones susceptibility profiles, heamolytic activities, deoxyribonuclease production were determined using Kirby –Bauer disc diffusion methods, Columbia Blood Agar (CBA) and Deoxyribonuclease (DNase) agar, respectively. The results showed that all the 46 clinical samples showed positive growth, with 24 (52.2%) having single bacterium isolated. Co-infection with two bacterial species was seen in 24 (28.3%), while polybacterial growth was present in 9 (19.6%) of the samples. Staphylococcus aureus was the most prevalent aerobic Gram positive cocci associated with acne vulgaris with 32 (42.1%) occurrences, followed by Staphylococcus epidermidis 26 (34.2%) and Micrococcus spp 18 (23.9%). Sixteen of the isolates produced α – haemolysin, 25 (32.9%) produced β – haemolysin and 35 (46.1%) produced no haemolysin (γ-haemolysis). Of the 16 α – haemolysin producers, Staphylococcus aureus produced the highest 9 (56.3%), followed by Staphylococcus epidermidis 5 (31.3%) and Micrococcus spp 2(12.5%). Of the seventy – six aerobic Gram positive cocci isolated only 33 (43.4) were DNase producers, while 43 (56.6) were non-DNase producers. Staphylococcus aureus were highly sensitive to Moxifloxacin, while 26 (81.3%) were sensitive to Lomefloxacin and Gatifloxacin. Staphylococcus epidermidis and Micrococcus spp were highly sensitive to Gatifloxacin, Moxifloxacin, Lomefloxacin and Levofloxacin. The results also showed that 17 (65.4%) and 13 (50.0%) of Staphylococcus epidermidis were sensitive to Pefloxacin and Nalidixic, respectively. Consequently, this study has shown that fluoroquinolones could be drugs of choice to administer to patients with acne vulgaris.