Antimicrobial susceptibility and management of bacterial skin and soft tissue infections at Moi Teaching and Referral Hospital, Eldoret, Kenya

Abstract

Background:Bacterial skin and soft tissue infections (SSTIs) are the second most common indication for antimicrobial therapy. The causative bacterial organisms are increasingly resistant, and are posing a great challenge and threat to public health, key among these being Methicillin-resistant Staphylococcus aureus (MRSA). There is little data on local antimicrobial susceptibility patterns in SSTIs and hence the approach to treatment remains a challenge. Objectives:To determine the antimicrobial susceptibility of bacterial organisms causing SSTIs and the antimicrobial management of SSTIs at the Moi Teaching and Referral Hospital (MTRH). Methods:This was a cross sectional descriptive study. Census sampling was done on patients diagnosed andadmitted with SSTIs at MTRH between January and December 2014. Pus and tissue from abscesses, cellulitis and wound infections were cultured. Bacteria were identified using gram stain and biochemical tests including indole, catalase, coagulase, oxidase, voges-proskeur, urease, bacitracin, aesculin, methyl red and citrate tests. Antimicrobial susceptibility was done using the disc diffusion method. Results:Out of 84 bacteria cultured, Staphylococcus aureus constituted 47.6%. MRSA constituted 45% of Staphylococcus aureus. Over 80% of Staphylococcus aureus were susceptible to vancomycin and ceftazidime. Likewise, other gram positive bacteria, including Enterococcus spp., coagulase negative staphylococci and Streptococcus pyogenes were susceptible to vancomycin and clindamycin. Gram-negative bacteria were 25, and most were susceptible to meropenem and amikacin (>80%). However, Acinetobacter baumanii were not susceptible to any antimicrobial tested. Flucloxacillin and metronidazole were most used as empiric therapy, which was effective against the etiologic bacteria in 18%. Conclusions:The most common cause of SSTIs was Staphylococcus aureus, which were susceptibile to vancomycin and clindamycin. Gram-negative bacteria were susceptible to meropenem and amikacin. Most empiric therapy was not appropriate. Recommendations:Vancomycin, clindamycin, meropenem and amikacin should be used for the empiric treatment of severe SSTIs. De-escalation of this antimicrobial therapy should then be done according to the antimicrobial susceptibility results.