Occurrence, ecological risk assessment and source apportionment of pharmaceuticals, steroid hormones and xenoestrogens in the Ghanaian aquatic environments.

Elevated levels of pharmaceuticals, steroid hormones and xenoestrogens (PSHXEs) in the aquatic environment pose a serious threat to the ecological balance. The endocrine disrupting PSHXEs in aquatic systems are linked to several adverse effects like reproductive health impairment, feminization, high mortality rate, decreased biodiversity etc. This study, therefore, sought to investigate the occurrence and the ecological risks posed by some selected PSHXEs and also conduct source apportionment of the PSHXEs in the Ghanaian aquatic environments. A total of 48 samples comprising 24 sediments and water each were taken from six waterbodies in Ghana. The samples were extracted using SPE cartridges for water and QuEChERS-dSPE for sediments. The analyses were done using Shimadzu Prominence UFLC 20A series. Ecological risk assessments were also conducted with the aid of USEPA T.E.S.T., whereas source apportionments were conducted using the APCS-MLR receptor model. Elevated mean total levels of PSHXEs ranging between 12,187 and 52,117 ng/L and 2,022-6,047 ng/g for water and sediment samples respectively were found. The risk quotients (RQ > 1) suggested a high risk posed by PSHXEs in water to organisms at the three trophic levels and also to benthic organisms in sediments of the Ghanaian aquatic environments for a short-term period. The APCS-MLR receptor model suggested three statistically significant sources (p < 0.05) designated by signature PSHXEs as domestic (major), mix hospital and industrial and agricultural waste sources. The source apportionment suggested increased use of steroid estrogens and anabolic drugs among the Ghana populace.

Evolutionary paths to macrolide resistance in a Neisseria commensal converge on ribosomal genes through short sequence duplications.

Neisseria commensals are an indisputable source of resistance for their pathogenic relatives. However, the evolutionary paths commensal species take to reduced susceptibility in this genus have been relatively underexplored. Here, we leverage in vitro selection as a powerful screen to identify the genetic adaptations that produce azithromycin resistance (≥ 2 µg/mL) in the Neisseria commensal, N. elongata. Across multiple lineages (n = 7/16), we find mutations that reduce susceptibility to azithromycin converge on the locus encoding the 50S ribosomal L34 protein (rpmH) and the intergenic region proximal to the 30S ribosomal S3 protein (rpsC) through short tandem duplication events. Interestingly, one of the laboratory evolved mutations in rpmH is identical (7LKRTYQ12), and two nearly identical, to those recently reported to contribute to high-level azithromycin resistance in N. gonorrhoeae. Transformations into the ancestral N. elongata lineage confirmed the causality of both rpmH and rpsC mutations. Though most lineages inheriting duplications suffered in vitro fitness costs, one variant showed no growth defect, suggesting the possibility that it may be sustained in natural populations. Ultimately, studies like this will be critical for predicting commensal alleles that could rapidly disseminate into pathogen populations via allelic exchange across recombinogenic microbial genera.

Perfluoroalkyl acids (PFAAs) in the Pra and Kakum River basins and associated tap water in Ghana.

Perfluoroalkyl acids (PFAAs) are persistent environmental pollutants that have been detected in various media including human serum. Due to concerns regarding their bioaccumulation and possible negative health effects, an understanding of routes of human exposure is necessary. PFAAs are recalcitrant in many water treatment processes, making drinking water a potential source of human exposure. This study presents the first report on contamination from PFAAs in river and drinking water in Ghana. The targeted PFAAs were perfluoroalkyl carboxylic acids (PFCAs) with C4-14 carbon chain and perfluoroalkane sulphonic acids (PFSAs) with C6, 8, 10. Five PFAA congeners - PFOA, PFOS, PFHxA, PFDA and PFPeA - were commonly detected in river and tap water. The mean concentrations of ∑PFAAs in the Kakum and Pra Rivers were 281 and 398ng/L, while tap water (supplied from the treatment of water from those rivers) contained concentrations of 197 and 200ng/L, respectively. PFOA and PFOS constituted about 99% of the ∑PFAAs. The risk quotient (RQ) attributed to drinking of tap water was estimated at 1.01 and 1.74 for PFOA and PFOS, respectively. For a country that has not produced these compounds, the RQs were unexpectedly high, raising concerns particularly about contamination from such emerging pollutants in local water sources. The study revealed limitations of local tap water treatment in getting rid of these emerging pollutants.