Browsing by Author "Mwega, Elisa"

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Antibiotic-resistant microbial populations in urban receiving waters and wastewaters from Tanzania
(Environmental Chemistry and Ecotoxicology, 2023) Ripanda, Asha Shabani; Rwiza, Mwemezi J; Nyanza, Elias Charles; Miraji, Hossein; Bih, Numfor Linda; Mzula, Alexanda; Mwega, Elisa; Njau, Karoli N; Vuai, Said Ali Hamad; Machunda, Revocatus L
Antimicrobial resistance against certain medications in the pathogenic microbial community is globally increasing due to the continual discharge and disposal of pharmaceuticals in the environment. The phenomenon resulted in significant antibiotic resistance among several exposed Enterobacteriaceae species, with wastewater treatment plants (WWTPs) and rivers serving as significant reservoirs. Despite antibiotic resistance being a tragedy, particularly in treating diseases by using antibiotics, local and regional studies indicating the severity, resistant species and the molecular level insight into these pathogens are scarce, thus requiring immediate intervention. This study, therefore, investigated wastewater from wastewater treatment ponds and receiving waters for the presence of resistant patho- gens through phenotypical and molecular approach screening of their genes. Among the 57 analyzed samples, 18 (67%, n = 27) isolates of Klebsiella spp.., 4 (80%, n = 5) isolates of Proteus spp., 1 (100%, n = 1) of isolated Pseudomonas aeruginosa and 6 (18%, n = 34) of E. coli found were resistant to at least 1 among the tested antibiotics. E. coli had an 83% higher proportion of multi-drug resistance (MDR) than Klebsiella spp.., which had 68.5%, and no MDR was shown by P. aeruginosa isolates. Among the 20 bacterial isolates of antibiotic-resistant genes, showed that E. coli harboured 39%, followed by 22% of Klebsiella spp. Eleven (11) isolates of these 20 (55%) contained sulphonamides resistant genes: Sul 1 (n = 4) and Sul 2 (n = 7). Ten (10) isolates (50%) contained the tetracycline- resistant genes in which 4 isolates showed the Tet A, Tet B – 1 and 5 isolates contained Tet D. β-lactamases (bla CTX-M and bla SHV) were found in 7 isolates (35%). The existence of these antibiotic-resistant species in the urban receiving and wastewater presents a threat of transmission of diseases to humans and animals that are not cured by the existing medications, jeopardizing public health safety.
Antimicrobial susceptibility of flavobacteriaceae isolates from nile tilapia (oreochromis niloticus) in Tanzania
(African Journal of Microbiology Research, 2020) Mwega, Elisa; Chengula, Augustino; Colquhoun, Duncan; Mutoloki, Stephen; Mdegela, Robinson; Evensen, Øystein; Wasteson, Yngvild
This study aimed to assess antimicrobial susceptibility of members of the family Flavobacteriaceae isolated from Nile tilapia (Oreochromis niloticus). Antimicrobial susceptibility of 67 Flavobacteriaceae isolates originating mainly from ponds and Lake Victoria against 19 antimicrobial agents was determined by the broth micro dilution method. Overall, most isolates were susceptible to enrofloxacin (97%; MIC 90 2 μg/ml) followed by novobiocin (85%, MIC 90, 4 μg/ml) and the aminoglycoside streptomycin (85%; MIC 90 , 128 μg/ml). Some isolates were also susceptible towards trimethoprim/sulfamethoxazole (77.6%), neomycin and florfenicol both at 62.7%. Susceptibility levels were low for tylosin tartrate (32.8%), clindamycin and sulphathiazole both at (23.9%), ceftiofur (6%), spectinomycin (6%) and tetracyclines/oxtetracyclines (4.5%). In contrast, β-Lactams (amoxicillin, penicillin), gentamycin and erythromycin exhibited very poor activity against Flavobacteriaceae isolates. The extent of antimicrobial susceptibility did not vary significantly among isolates from farmed and wild fish isolates (P > 0.01). The highest Multiple Antimicrobial Resistance (MAR) index was observed in Chryseobacterium indologenes (0.89) and the lowest in Chaetoderma indicum isolates (0.32). Our results indicate that most of Flavobacteriaceae isolates are multidrug resistance, and this may be associated with intrinsic resistance mechanisms to a broad range of antimicrobial agents. However, the need remains to carryout in-depth study to understand better the underlying genetic mechanisms given that the magnitude and trend for susceptibility was comparable between isolates from aquaculture and fisheries. The findings from this study give us insight into appropriate choice of antimicrobial agents for effective treatment of infections caused by these isolates.
Determination of bacterial load and antibiotic Susceptibility testing of bacteria isolated from students’ toilets At Sokoine University of Agriculture, Morogoro, Tanzania
(Journal of Health, Medicine and Nursing, 2014) Chengula, Augustino; Lushino, Asha; Mzula, Alexanda; Mafie, Eliakunda; Mwega, Elisa; Makundi, Isaac; Peter, Emma
The circulation of infectious diseases in the community settings in urban and rural areas remains to be a hectic problem. One of the sources of microbial diseases is toilets. This study aimed at isolating, identifying and establishing bacterial loads associated with public restrooms in students’ hostels at Sokoine University of Agriculture in Morogoro, Tanzania. Samples were collected from a total of thirty toilets (60 samples) in different surfaces; (i) surfaces associated with toilets (toilet seats and toilet bowls), (ii) surfaces routinely touched with hands (door handles in and out of the restrooms, faucet handles and toilet flush handles) and (iii) the restroom floors. Samples were inoculated in MacConkey and Blood agar and then incubated at 37 o C for 24 hours. All isolates were sub cultured and identified based on macro- and micro-morphology and Standard Biochemical Tests. The establishment of total bacteria load was done using Standard Plate Count Method. The sensitivity testing of the isolates were carried out using the Disk Diffusion Method on nutrient agar plate. The following bacteria genera and species were isolated from the students’ toilets; Staphylococcus aureus (25.0%), Escherichia coli (36.7%), Pseudomonas aeruginosa (13.3%), Streptococcus pyogenes (6.7%), Proteus mirabilis (6.7%) and Klebsiella pneumonia (11.6%). The results from total bacterial count indicated that the surfaces routinely touched with hands had highest bacteria load compared to restroom floor and toilet seats. However, the differences of means among the surfaces were not statistically significant (P= 0.6762). Sensitivity testing of the isolates against commonly used antibiotics in the study area showed that all bacterial isolates tested were resistant and intermediate resistant to at least one antibiotic.