Antibiotic Resistance Profiles among Enteric Bacteria Isolated from Wastewater in Septic Tanks

  • Christopher Mutuku Department of Biological Sciences, Chuka University, P.O Box, 109-60400, Chuka, Kenya.
Keywords: Enteric bacteria, multidrug resistance, septic tanks, wastewater.


This study was carried out to assess the antibiotic resistance profiles of 95 isolates of enteric bacteria obtained from wastewater in septic tanks within Chuka University in Kenya which houses laboratories, animal farm, crop demonstration and research farm, student hostels and a health Centre. The isolates were differentiated into four genera. E.coli was the predominant organism (41 isolates). The others were Salmonella (19), Proteus (13) and Klebsiella (22). The strains were subjected to different classes of antibiotics including β-lactams, macrolide, tetracycline and sulfa drugs. The study revealed an increase in resistance to Penicillins and a decreased resistance to the tetracycline and the cephalosporin assayed. 84.2% (80) of the strains resisted amoxyclav, 76.8% (73) ampicillin and 64.2% (61) oxacillin. Others were vancomycin 47.4% (45), erythromycin 47.4% (45), co-trimoxazole 41.1% (39), doxycycline 36.8% (35) and ceptazidime 31.6% (30). All the strains recorded multiple drug resistance with E.coli being the most resistant to the antibiotics, followed by Salmonella, Klebsiella and Proteus. Drug resistance in E.coli was significantly different from the other strains, P<0.05. However, drug resistance between Salmonella and Klebsiella strains was not significantly different (P>0.05). Drug sensitivity among the four bacterial genera was not significantly different (P=0.01). It is anticipated that the findings of this study will provide an understanding of the changing antibiotic resistance trends in enteric bacteria from sewage effluent and help design improved sewage treatment strategies to contain the spread of drug resistance which poses a great public health risk. The report also emphasizes the necessity of continuous surveillance of antibiograms of enteric bacteria in order to rationalize their treatment protocols.


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