Open Access Original Research Article

Bacterial Contaminants and Heavy Metal Accumulating Potentials of Fin-Fishes (Synodontis obesus and Marcusenius senegalensis) from Humic Freshwater

Okon, Ufokette Christopher, Umana, Senyene Idorenyin, O. K. Fatunla, N. O. Abiaobo, Essien, Joseph Peter

Journal of Advances in Microbiology, Page 1-14
DOI: 10.9734/JAMB/2017/36528

The bacterial contaminants and heavy metal accumulating potentials of fin-fishes (Synodontis obesus and Marcusenius senegalensis) from the humic ecosystem of Eniong River, Akwa Ibom State were investigated. The results obtained revealed that the bacterial loads varied with the type of fin-fish and were much higher in fish intestines, when compared with the skin and gills. The heterotrophic bacterial loads obtained exceeded the 1.2 x 105cfu/g limit recommended for fresh fishes. High and unsafe fecal coliform (1.1 ± 0.1 x 103cfu/g -2.0 +0.39x 103cfu/g) loads were also obtained. Heavy metal analysis also revealed the presence of Cd, Cr, Cu, Ni and Pb in the humic sediment. Concentrations of Cd (4.71 ± 0.34 to 4.91± 0.39 mg/kg), Cr (18.06 ± 5.78 to 20.22 ± 1.11 mg/kg), Cu (35.33 ± 3.25 to 40.28 ± 2.44 mg/kg), Ni (2.16 ± 0.07 to  2.26 ± 0.18 mg/kg) and Pb (175.85 ± 7.75 to 191. 08 ± 20.11 mg/kg) were found in the order Pb>Cu>Cr>Cd>Ni. Sequential extraction method (SEM) of analysis revealed the poor bioavailability status of heavy metals in sediment. It also showed that the percentage of bio-available and non-bio-available fractions of metals in sediment varied with the type of metals. Cu with 62.04% availability rate was the most bio-available element, as against Pb with 25.22% availability rate. These correspond to their 32.4% and 65.2 % residual potency rates. The calculated Biota to Sediment Accumulating Factor values for heavy metals in the fin-fishes revealed varied levels of accumulation in fishes. Cu (3.73±1.39 mg/kg) in Synodontis obesus was the most accumulated. However, analysis of the bio-accumulation factors (BCF values) revealed generally low accumulation determined by fish type as well as the metal fractions and bio-available status. The results indicate the poor microbiological quality and poor potential of the fin-fishes as sentinel organism for metals contamination monitoring. These call for proper processing of aquatic foods  as well as routine monitoring (but with alternative sentinels) to arrest the growing influence of anthropogenic activities on the level of heavy metals in Eniong River.


Open Access Original Research Article

Phytochemical and Antimicrobial Activity Screening of Ether Extract of Afromomum melegueta Seed

F. U. Eneh, C. N. Ezekwesili, G. C. Ugochukwu, U. T. Okolo

Journal of Advances in Microbiology, Page 1-8
DOI: 10.9734/JAMB/2017/36869

Aim: The search for new antimicrobials as a result of antibiotic failure has led to the development of new antibiotic scaffolds. In the African sub-continent, this has translated to exploration of her rich flora for potential leads. This work investigated the antimicrobial potential of ether extract of Afromomum melegueta seeds against three candidate microbes- Escherichia coli, Staphylococcus aureus and Candida albicans.

Methodology: Seeds of A. melegueta were extracted with petroleum ether using cold maceration technique; standardized chemical tests were employed for phytochemical screening and the agar-well diffusion method used for antimicrobial analysis of the obtained extract.

Results: Findings indicate that the extract displayed dose-dependent inhibitory effect on the growth of E. coli, S. aureus and C. albicans with maximum inhibition zones of 5, 10 and 3 mm at extract concentration of 25, 20 and 25%, respectively. The observed antimicrobial activity may be as a consequence of the phytochemistry of the seeds, as preliminary phytochemical screening revealed the seeds to contain saponin, flavonoid, cardiac glycoside, alkaloids, cyanogenic glycosides, tannin and phenolic compounds. The ability of the extract to inhibit microbes with diverse morphology indicates that the antimicrobial bioactive principles therein may have broad specificity.

Conclusion: The result of our study further reinforces the importance of A. melegueta seeds in ethnomedical practices and its use in culinary. Further investigation is however needed to isolate and mechanistically investigate the bioactive antimicrobial principles for potential development into generic antimicrobials.


Open Access Original Research Article

Occurrence of Bacterial Contaminants in Fin-fishes (Clarias gariepinus and Coptodon guineensis) from Humic Freshwater Ecosystem of Eniong River, Itu, Akwa Ibom State, Nigeria

Senyene I. Umana, Ufokette C. Okon, Mfoniso P. Uko, Maria P. Bassey

Journal of Advances in Microbiology, Page 1-12
DOI: 10.9734/JAMB/2017/36529

The occurrence of bacterial isolates in fin-fishes (Clarias gariepinus and Coptodon guineensis) from the humic ecosystem of Eniong River, Akwa Ibom State was investigated. The results obtained from pour plate analysis showed that the fin-fishes contained bacterial contaminants. The bacterial   loads varied with the type of fin-fish and were much higher in fish intestines, when compared with the skin and gills. The heterotrophic bacterial loads obtained exceeded the 1.2 x 105 cfu/g limit recommended for fresh fishes. High and unsafe fecal coliform (1.1 ± 0.57 x 103 cfu/g -2. ± 0.26 x 103 cfu/g) loads were also obtained. The culture-able bacteria species associated with the fin-fish samples include Staphylococcus sp, Klebsiella sp, Bacillus sp, Enterobacter, Streptococcus sp, Micrococcus sp, Lactobacillus, Serratia sp, Proteus sp, Salmonella sp, Shigella sp, and Escherichia coli. The percentage of occurrence of the isolates in the various fish samples was also found to vary with the fish species. Staphylococcus sp had the highest rate of occurrence of 63% and 44.4% in C. gariepinus and C. guineensis respectively while the least prevalent organism was Micrococcus sp with 7.41%, and Serratia and Shigella sp with 11.1% for C. gariepinus and C. guineensis respectively. Twelve bacterial species with variable virulent potentials were isolated. The analysis revealed that each of the isolates exhibited varying degree of virulence. Of the 12 bacterial isolates obtained from the various fish samples, ten (Bacillus cereus, Micrococcus sp, Streptococcus sp., Proteus sp, Serratia sp, Salmonella sp., Shigella sp., E. coli, Enterobacter sp and Lactobacillus sp had the potentials to produce lipases enzyme. This enzyme is responsible for breaking down lipids.  Among the isolates Stahylococcus aureus was the most virulent. The results indicate poor microbiological quality. These call for proper processing of aquatic foods as well as routine monitoring.


Open Access Original Research Article

Multidrug Resistance, V16S rRNA Gene Sequencing, High Frequency of Toxins Encoding Genes (tox, tdh, trh) in Parahaemolyticus and Non -parahaemolyticus Vibrios Isolated from Shellfish

Amira Mohamed Zakaria, Dalia Mohamed Sabri

Journal of Advances in Microbiology, Page 1-10
DOI: 10.9734/JAMB/2017/36875

PCR amplification of V16S-rRNA, tox, tdh, trh was applied as a molecular typing approach to identify potentially toxigenic vibrio species. Thirty vibrio strains were isolated from several types of shellfish collected from Ismailia district, Egypt. Isolates were recognized by conventional biochemical features and PCR amplification then tested for their sensitivity against twelve antibiotics. Multiple sequences alignment of V16S-rRNA indicated the high incidence of V.parahaemolyticus (n= 6) V. cholerae (n=5) and V. fluvialis  (n=5) among the investigated groups. V. harveyi (n=3), V. alginolyticus ( n=2 )V. vulnificus (n=1) and (n=8) vibrio sp were reported as well. Toxins encoding genes (tox, tdh, trh) shown high incidence frequency in the majority of the identified vibrio species. Identified isolates were reported as potential pathogenic and multiple antibiotic resistant with noticeably high resistant indexes ranged from (0.5-1). The results significantly emphasized that the isolates have been originated from potential risk sources of infection.


Open Access Original Research Article

RpoB Gene-Based Characterization of Non-Tuberculous Mycobacteria in Zimbabwe

Wadzanai Manjeese, Boniface Muzividzi, Joshua Mbanga, Jonathan Mufandaedza, Nyasha Chin’ombe

Journal of Advances in Microbiology, Page 1-7
DOI: 10.9734/JAMB/2017/36783

Aims: To characterize archived nontuberculous Mycobacteria (NTM) samples previously isolated from humans across Zimbabwe during the 2014 national tuberculosis survey. The rpoB gene of the isolates was targeted for characterization.

Study Design:  The research was an observational study where NTM samples previously isolated from Zimbabwean population were analysed by rpoB gene sequencing and phylogeny to identify NTM species.

Place and Duration of Study: Department of Medical Microbiology, University of Zimbabwe between September 2015 and July 2016.

Methodology: We obtained 99 NTM DNA samples from 963 NTM at NMRL, which we characterised using rpoB gene analysis after PCR amplification. The amplicons were sequenced and bioinformatics tools were used for speciation. The rpoB gene of DNA extracts from the NTM was amplified and the sequences were analysed using bioinformatics tools to identify the NTM to species level.

Results: From the 99 NTM isolates, 40 were sequenced and analyzed. The NTM were identified as belonging to 13 species. The species were M. palustre    (14.8%), M. aroisense (29.6%), M. parascrofulaceum (3.7%), M. arupense (7.4%), M. asiaticum (3.7%), M. malmoense (3.7%), M. lacus (3.7%), M. avium (7.4%), M. nonchromogenicum  (3.7%), M. gordonae (3.7%), M. aromaticivorans (3.7%), M. novocastrense (3.7%), M. bourgelatii (3.7%). One sample (3.7%) belonged to Mtb complex species (3.7%) and another one (3.7%) was closely related to S. oryzae. The most common species belonged to M. aroisense and M. palustre. The species showed a high degree of rpoB sequence diversity. Sequence analysis of the rifampicin resistance determining region (RRDR) showed the existence of only silent mutations.

Conclusion: Species of NTM from Zimbabwe showed a high degree of rpoB gene sequence diversity. This characteristic feature can therefore be used in diagnosis and identification of NTM in clinical specimens.