Isolation and characterization of bacteria recovered from wounds of hospitalized diabetic patients in Northern KwaZulu-Natal
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Date
2016
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University of Zululand
Abstract
Diabetes mellitus is a world health concern with about 2.28 million cases recorded in South Africa in 2015. One of the complications of diabetes is the development of chronic wounds that contribute to longer hospitalization and bacterial infection. If not treated properly, the wounds may lead to the emergence of antibiotic resistant bacteria that require viable alternative treatment. The aim of the study was to isolate and identify bacteria present in wounds of diabetic patients, characterize their antibiotic susceptibility patterns and determine the potential of medicinal plant extracts to inhibit bacterial growth. The wound specimen were collected and plated on selective and differential media. Identification was done through biochemical characterization, API and 16S rDNA sequencing. The antibiotic susceptibility patterns were determined through the Kirby-Bauer disk diffusion assay while the antibacterial activities of the plant extracts were evaluated through the agar-well diffusion method. The plants were first screened for the presence of phytochemicals and extracts of dichloromethane, acetone and water were prepared separately. The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) of the active extracts were determined. A total of 42 isolates were recovered from 83% of the patients sampled from three hospitals (X, Y, and Z). Gram-negative bacilli from Enterobacteriaceae were predominant followed by Staphylococci spp and Enterococcus faecalis. The bacteria exhibited resistance to penicillin (100%), ampicillin (91%), cefepime (60%), ceftazidime (55%) and gentamicin (52%). Hospital X’s bacteria were found to be most resistant to erythromycin (80%) and ciprofloxacin (70%), while hospital Z’s bacteria were most resistant to vancomycin (50%) and penicillin (50%), with Hospital Y’s bacteria showing the most resistance to imipenem (45%). Multidrug resistance patterns were exhibited by Enterococci (83%), Enterobacteriaceae (55%), non-Enterobacteriaceae bacilli (50%), Staphylococci (50%) and Gram-positive bacilli (33%). Most bacteria tested on plant extracts were resistant. However, zones of inhibition ranging from 11±0.1-22±0.6 mm, were observed against the acetone extract of P. glomerata and the aqueous and acetone extracts of C. fendleri. The MIC values ranged from 10- 20 mg/ml and MBC values at 5-v > 20 mg/ml. The observed antibacterial activities could be attributed to the presence of phytochemicals in the plants. The resistance associated with bacteria recovered in diabetic wounds is a serious health concern that limits antibiotic treatment options as it has been observed the study, therefore necessitating the need to explore lead active compounds in medicinal plants that may aid wound healing.
Description
A dissertation submitted to the Faculty of Science and Agriculture in fulfillment of the requirements for the Degree of Masters in the Department of Biochemistry and Microbiology at the University Of Zululand, 2016
Keywords
bacteria --wounds --diabetes --South africa