Antibiotic susceptibility of four Enterobacteriaceae strains (Enterobacter cloacae, Citrobacter freundii, Salmonella typhi and Shigella sonnei) isolated from wastewater, surface water and groundwater in the equatorial zone of Cameroon (Central Africa)

Abstract

The health problems caused waterborne pathogens bacteria belonging to the Enterobacteriaceae family are aggravated by the rise of antimicrobial resistant bacteria phenomenon. This has been identified as one of the biggest global health challenges. The present study aims to make a comparative approach of the sensitivity/resistance to antibiotics of 4 Enterobacteriaceae Enterobacter cloacae, Citrobacter freundii, Salmonella typhi and Shigella sonnei isolated from wastewater, streams and groundwater in Yaounde town (Cameroon, Central Africa). Bacteria were isolated using standard methods their identification using the API 20E systems. The antibiogram tests were carried out using the Müller-Hinton antibiotic disc diffusion method. Results showed that inhibition diameters of antibiotic varied (P<0.05) with respect to the bacterial species on one hand, and with respect to the type of water harbored cells on the other hand. The proportion of bacterial strains of each isolated species, and which were sensitive or resistant varied from one antibiotic to another within the same antibiotics family. For β-lactams tested, no E. cloacae strain has been sensitive. The proportion of sensitive strains of other species varied between 5.88% and 23.53%. For the 2 aminoglycosides tested, 5.88% of the strains of each isolated species were resistant to gentamycin. Of the 3 quinolones tested, all strains of E. cloacae and C. freundii isolated were fully resistant to Norfloxacin and of Ofloxacin. For the 3 Sulfonamides+trimethoprim, all strains of C. freundii and S. typhi isolated were resistant to Nurofurantoin and Fosfomycin. Most of bacteria strains isolated in wastewater and surface water were resistant to all the antibiotics tested. Many bacterial strains tested were multi-resistant. This multidrug resistance was more marked in E. cloacae and C. freundii species isolated from wastewater and surface water. This represents a health risk for humans and the aquatic environment.

Sensitivity to antibiotics of bacteria of the genus Aeromonas isolated from developed groundwater points and some surface water points in the Commune of Nkolafamba (Centre Cameroon)

“…The results of the antibiogram tests mostly show Aeromonas resistant to the antibiotics tested, although there may be intermediate reactions or the bacteria are sometimes sensitive depending on the species identified and the water point sampled (tables VI and VII). Similar results were obtained by [13] on Pseudomonas isolated from Douala and Yaoundé rivers ; and by [32], who studied the importance of the properties of the aquatic biotope in Yaoundé on the susceptibility of certain Enterobacteriaceae to antibiotics from the aminoglycoside family. This strong resistance is due to the constant presence of residues of active substances (fertilizers, detergents, drugs) in the water, thus increasing the contact time and bacterial resistance according to the one health approach [29].…”

“…Correlations were noted between the diameters of inhibition of the bacteria after the antibiogram and the physicochemical variables of the water sampled (Table XI). Antibiotic resistance is a function of the place of isolation of the bacterial species considered and of the abiotic variables of the place of isolation [32].…”

Impact of heavy metal residues on the diversity of bacteria isolated from a few water points in areas of agricultural activity

“…However, this contamination depends on the pollution load of the contaminant and the permeability of the overlying soil. This result is similar to that obtained by [25], in groundwater and surface water in the city of Yaoundé.…”

“…These results have revealed the presence of several pathogens such as Escherichia coli, Salmonella, Shigella among others, witnesses of faecal contamination. Similar results were also obtained by [25], in Yaoundé and by [27] in Soa, who have analyzed drinking water and bacteria isolated witnesses of faecal contamination and opportunistic bacteria such as E. coli, Vibrio, Klebsiella, Salmonella, Shigella and Pseudomonas.…”

“…Moreover, the high concentration and the permanent presence of Salmonella throughout the study and Vibrio particularly during the dry seasons, provides information on the degree of pollution of these waters and would confirm the idea of the permanent reappearance of epidemics and their monitoring [25],The finding that bacteria of the genus Vibrio were most often identified during dry seasons could be due to the fact that according to [10]; water in the dry season is rarely renewed, which weakens the rate of natural purification of watercourses. The content of these waters in bacteria of the Vibrio and Salmonella genera is higher than the maximum allowable concentrations for these microorganisms in drinking water.…”