Antibiotic resistance has become a major public health concern around the world. This is exacerbated by the non-discovery of novel drugs, the development of resistance mechanisms in most of the clinical isolates of bacteria, as well as recurring infections, hindering disease treatment efficacy. In vitro data has shown that antibiotic combinations can be effective when microorganisms are resistant to individual drugs. Recently, advances in the direction of combination therapy for the treatment of multidrug-resistant (MDR) bacterial infections have embraced antibiotic combinations and the use of nanoparticles conjugated with antibiotics. Nanoparticles (NPs) can penetrate the cellular membrane of disease-causing organisms and obstruct essential molecular pathways, showing unique antibacterial mechanisms. Combined with the optimal drugs, NPs have established synergy and may assist in regulating the general threat of emergent bacterial resistance. This review comprises a general overview of antibiotic combinations strategies for the treatment of microbial infections. The potential of antibiotic combinations with NPs as new entrants in the antimicrobial therapy domain is discussed.

Coastal water resources are habitually exposed to indiscriminate anthropogenic pollution. However, due to their negative consequences to the public health, recreational waters require continuous monitoring for disease-causing organisms as a way of preventing ailments associated with swimming. As a result, the present study assessed the physicochemical parameters and microbial loads of water samples collected from six different sampling points on Kidd's Beach using standard analytical procedures. Generated data were analysed with One-way ANOVA and spearman correlation (at 95%). The physicochemical qualities varied as follows: pH (7.21–8.23), temperature (18.46–27.63 °C), turbidity (0–25.67 NTU), electrical conductivity (22723–62067 μS/cm), total dissolved solids (7662–31037 mg/L), and salinity (8.95–41.84 PSU). All these measured parameters were significantly different ( P < 0.05) with respect to the sampling sites. Presumptive Enterococcus counts ranged from 64 – 168 CFU/100 mL of water samples. Out of 409 presumptive Enterococcus isolates obtained from the culture-based method, 67 were confirmed to be Enterococcus by PCR-techniques. From the 67 confirmed isolates, 19 (E. faecalis ) and 40( E. feacium ) while 8(other species that were non-targeted). Findings from this study shown that Kidd's Beach water samples contain some pathogenic bacteria that pose high risk to the public health and make it to be unfit for recreational use when compared to DWAF and US EPA guidelines. Therefore, effort should be made to strictly control all activities contributing to the level of pollution in the marine environment.

Multidrug-resistant organisms have increased the prevalence of infectious diseases and have become the leading source of death globally. The adverse effects associated with conventional antibiotics cannot be underestimated, and as a result, the quest for antibacterial agents has received great attention over the years. Therefore, the current research was designed to synthesize and examine the antibacterial properties of two metallic nanoparticles, silver nanoparticles (AgNPs) and zinc oxide nanoparticles (ZnONPs), as well as their antibiotic combination therapy against multidrug-resistant bacteria. AgNPs and ZnONPs were synthesized by the coprecipitation method and characterized. Thereafter, their antibacterial activity against multidrug-resistant bacteria was investigated using the microdilution technique. Subsequently, the interactions between the synthesized nanoparticles and antibiotics were evaluated by checkerboard assay. Time-kill assays were carried out to assess bacteriostatic or bactericidal effects, and the cytotoxicity study was carried out by MTT assay. The SEM analysis of AgNPs and ZnONPs were spherical with an average size of 21.03 and 43.37 nm, respectively. FTIR analysis showed the characteristics of the metal−oxygen vibrational band for both materials around 450 cm −1 , which indicated the successful synthesis of these antibacterial agents. The EDX characterization revealed Zn and O with 77.89% and 18.24% abundance in ZnONPs and Ag with 95.65% abundance in AgNPs. UV−vis absorption spectra of AgNPs was obtained around 400 nm. ZnONPs showed a moderate antibacterial effect against Enterococcus species with a MIC range of 2.5−5 mg/mL, while AgNPs demonstrated a strong antibacterial effect against the tested bacterial strains with a MIC range of 0.078−0.039 mg/mL. The ZnONPs were found to be cytotoxic against Vero cell lines at the tested concentrations, whereas AgNPs had no cytotoxic effect at lower concentrations. Their combination activities showed synergetic and additive effects. These findings revealed that these synthesized materials could serve as alternate antibacterial agents against multidrug-resistant Acinetobacter baumanni and Enterococcus species.

Enterococci are a group of significant disease-causing bacteria, which have developed resistance to several conventionally used antibiotics. Of the 67 confirmed Enterococcus species from Kidd's Beach, 40 (59.7%) were E. faecium, 19 (28.4%) were E. faecalis. The highest level of resistance was observed against rifampicin (83.6%) followed by erythromycin (64.2%), tetracycline (52.2%), linezolid (46.3%), tetracycline (46.3%), and vancomycin (32.8%). Ninety-six per cent of the Enterococcus spp. was found to be multi-drug resistant. MAR indices vary from 0.3 to 0.9. Two virulence determinants (ace and gelE) were detected and six resistance determinants were identified as follows: ermB (19%), tetM (30%), tetL (19%), gyrA (13%), ampC (1.5%) and Van C2/3 (4.5%). The presence of enterococci (E. faecium and E. faecalis) in Kidd's Beach waters harbouring virulence genes that facilitate multiple antibiotic resistance signifies a possible health threat for beach goers.

The composition and approximate concentrations of three trace metals-iron (Fe), zinc (Zn) and magnesium (Mg)-of 160 samples of Macrobrachium vollenhovenii (African river prawn) from Badagry creek were investigated for four months across the rainy and dry seasons. Length and weight of the prawns varied from 15.0cm-17.6cm and 72.76g-130.65g respectively. The approximate analysis was performed in triplicates and the collected data were analyzed using analysis of variance and T-test. Mean values for protein were 52.18±1.11% (rain) and 43.13±1.13% (dry); lipids were 9.65±0.65% (rain) and 3.50±0.55% (dry); ash were 23.39±1.06% (rain) and 12.00±1.11% (dry); crude fibre were 9.15±0.42% (rain) and 9.35±6.08% (dry); moisture content were 4.08±0.44% (rain) and 31.25±5.23% (dry), and carbohydrate were 1.58±0.07% (rain) and 1.35±0.17% (dry). Protein, ash, moisture and lipids values at different seasons were significantly different (p = 0.05). The trace metal values of the species were within standard recommended range set by World Health Organization. The mean values for zinc (Zn) were 5.10±0.64 (rain) and 5.16±0.27 (dry) mg/100g; magnesium (Mg)-20.00±1.02 (rain) and 18.00±1.10 (dry) mg/100g and iron (Fe)-3.03±0.40 (rain) and 2.59±0.39 (dry) mg/100g. There was no significant difference of Zn and Fe contents between seasons (p = 0.05), but the values for magnesium were significantly different (p = 0.05). This study indicated that, Macrobrachium vollenhovenii, from Badagry creek could be very useful as an alternative source of high-quality protein, energy and mineral supply for human consumption and even for feed formulation for animals because they contain considerable amount of trace metals.