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. Gramnegative 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.