Physiochemical analyses and molecular characterization of heavy metal-resistant bacteria from Ilesha gold mining sites in Nigeria

BACKGROUND

The contribution of the processes involved and waste generated during gold mining to the increment of heavy metals concentration in the environment has been well established. While certain heavy metals are required for the normal functioning of an organism, certain heavy metals have been identified for their deleterious effects on the ecosystem and non-physiological roles in organisms. Hence, efforts aimed at reducing their concentration level are crucial. To this end, soil and water samples were collected from Ilesha gold mining, Osun State, Nigeria, and they were subjected to various analyses aimed at evaluating their various physicochemical parameters, heavy metal concentration, heavy metal-resistant bacteria isolation, and other analyses which culminated in the molecular characterization of heavy metal-resistant bacteria.

RESULTS

Notably, the results obtained from this study revealed that the concentration of heavy metal in the water samples around the mining site was in the order Co > Zn > Cd > Pb > Hg while that of the soil samples was in the order Co > Cd > Pb > Hg > Zn. A minimum inhibitory concentration test performed on the bacteria isolates from the samples revealed some of the isolates could resist as high as 800 ppm of Co, Cd, and Zn, 400 ppm, and 100 ppm of Pb and Hg respectively. Molecular characterization of the isolates revealed them as Priestia aryabhattai and Enterobacter cloacae.

CONCLUSION

Further analysis revealed the presence of heavy metal-resistant genes (HMRGs) including merA, cnrA, and pocC in the isolated Enterobacter cloacae. Ultimately, the bacteria identified in this study are good candidates for bioremediation and merit further investigation in efforts to bioremediate heavy metals in gold mining sites.

Abstract S3-07: Impact of radiotherapy on complications and patient-reported satisfaction with breast reconstruction: Findings from the prospective multicenter MROC study

Background: Patients considering both post-mastectomy radiation (RT) and reconstruction require robust information regarding the expected outcomes of different combinations of approaches in order to make preference-concordant decisions.

Methods: In a prospective multicenter cohort study (the Mastectomy Reconstruction Outcomes Consortium, MROC, funded by NCI 1RO1CA152192) of women diagnosed with breast cancer at 11 institutions between 2012-15, we compared responses of 553 radiated and 1461 non-radiated pts who received different approaches to reconstruction. The primary dependent variables of interest were development of any breast complications (e.g. hematoma, wound infection) by one year post-reconstruction, along with satisfaction measured with the validated BREAST-Q instrument. Mixed-effects regression models assessed impact of reconstruction type and RT on the outcomes of interest. Covariate adjustment included reconstruction timing, age, extent of disease, bilateral vs unilateral treatment, chemotherapy receipt, nodal management, BMI, smoking, diabetes, race, ethnicity, education, employment, income, marital status, and hospital site.

Results: Median age was 49. Bilateral mastectomy was received by 45.6% of radiated and 53.3% of non-radiated pts (p=0.002). Autologous reconstruction was more commonly received by radiated pts (38.3% vs 25.1%, p<0.001). Immediate reconstruction was less common in radiated pts (82.6% vs 95.6%, p<0.001). By one year, at least one complication occurred in 28.8% of radiated pts (30.8% of implant pts and 25.5% of autologous pts) and 22.3% of non-radiated pts (20.4% of implant pts and 28.1% of autologous pts). Among pts with ≥2 years of follow up, a complication had occurred by 2 years in 34.1% of 331 radiated pts vs 22.5% of 946 non-radiated pts. Multivariable analysis showed immediate reconstruction, bilateral treatment, & higher BMI to be predictive of developing a complication by one year. RT effect differed by reconstruction type; RT was associated with 2.1 (95% CI = 1.45, 3.10) times higher odds of complication in implant pts, while showing no difference in autologous pts (OR=1.3, 95% CI = 0.76, 2.09). RT effect on patient outcomes also differed by reconstruction types. In implant pts, adjusted mean BREAST-Q satisfaction with breast scores were significantly lower in radiated pts than in non-radiated pts (51.5 vs. 58.0 at 1 year, p<.001; 48.9 vs. 59.8 at 2 years, p<.001), while satisfaction in autologous pts did not differ by radiation (61.3 in radiated vs. 63.5 in non-radiated at 1 year; 62.8 vs. 65.8 at 2 years). Similarly, in implant pts, satisfaction with outcomes was significantly lower in radiated versus non-radiated pts (66.5 vs. 70.8 at 1 year; p=0.03; 64.4 vs. 70.6 at 2 years, p =0.03), while there were no significant differences in autologous pts (72.7 vs. 75.2 in radiated vs. non-radiated at 1 year; 71.3 and 75.3 at year 2).

Conclusions: In the largest prospective multicenter study of outcomes of breast reconstruction to date, autologous reconstruction appears to yield superior patient-reported outcomes and lower risk of complications than implant-based approaches among patients receiving PMRT.

Citation Format: Jagsi R, Momoh AO, Qi J, Hamill JB, Billig J, Kim HM, Pusic AL, Wilkins EG. Impact of radiotherapy on complications and patient-reported satisfaction with breast reconstruction: Findings from the prospective multicenter MROC study [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr S3-07.