Evaluation of microbiological profile and antibiogram of aerobic bacteria isolated from pus samples

Abstract

Purulent wound infections are quite complicated to manage because of multidrug resistant bacteria. The main purpose of the present study was to assess the prevalence, microbiological profile and antibiograms of aerobic bacteria isolated from pus samples. One hundred pus sam-ples sent to the microbiology laboratory from surgical departments over a period of six months were analyzed. Isolation and detection of culture isolates was done by using standard bacteriological techniques and antibiotic susceptibility testing was performed by disc diffusion method by following CLSI guidelines on Muller-Hinton (MH) agar. Highest number of pus samples were from incision and drainage (23.8%) followed by chronic non-healing ulcer (19.04%). Twenty one different bacterial isolates were obtained from one hundred pus samples. S. aureus was the predominant bacteria (28.5%) followed by coagulase-negative Staphylococci (23.8%). The results of the antibiotics susceptibility testing illustrated that majority of the isolated organisms were MDR. S. aureus showed highest sensitivity to antibiotics like linezolid (83.3%) and teicoplanin (50%). Among the five isolated strains of coagulase-negative Staphylococci (CONS), three of them were MDR and the other two showed sensitivity to antibiotics cefaperazone, co-trimoxazole and ticarcillin/clavulanic acid (20%). Among the 9 isolates of Enterobacteriaceae, one isolate of E. coli (11.1%), two isolates of Klebsiella species (22.2%) showed ESBL pro-duction. The isolated four strains of P. aeruginosa showed ESBL pro-duction (44.4%) by CAZ/CA antibiotic susceptibility testing. These or-ganisms were screened for carbapenemase production through Modified Hodge test, 5 strains possess carbapenemase enzyme pro-duction (71.4%) and thus acquire resistance to carbapenem antibiotics. Carbapenemase production was not detected in the 2 isolates of P. aeruginosa among the 4 tested strains. The overall results showed that 85% of the isolated strains showed MDR to certain classes of antibiotics.