Metal and antibiotic-resistance in psychrotrophic bacteria from Antarctic Marine waters

Abstract

In the wake of the findings that Antarctic krills concentrate heavy metals at ppm level, (Yamamoto et al. 1987), the Antarctic waters from the Indian side were examined for the incidence of metal and antibiotic-resistant bacteria during the austral summer (13th Indian Antarctic expedition) along the cruise track extending from 50 degrees S and 18 degrees E to 65 degrees S and 30 degrees E. The bacterial isolates from these waters showed varying degrees of resistance to antibiotics (Chloramphenicol, ampicillin, streptomycin, tetracycline and kanamycin) and metals (K(2)CrO(4), CdCl(2), ZnCl(2) and HgCl(2)) tested. Of the isolates screened, about 29% and 16% were resistant to 100 ppm of cadmium and chromium salt respectively. Tolerance to lower concentration (10 ppm) of mercury (Hg) was observed in 68% of the isolates. Depending on the antibiotics the isolates showed different percentage of resistance. Multiple drug and metal-resistance were observed. High incidence of resistance to both antibiotics and metals were common among the pigmented bacterial isolates. Increased resistance decreased the ability of bacteria to express enzymes. The results reiterate previous findings by other researchers that the waters of southern ocean may not be exempt from the spread of metal and antibiotic-resistance.

Insight into heavy metal resistome of soil psychrotolerant bacteria originating from King George Island (Antarctica)

“…Moreover, in 162 strains co-resistance (i.e., joint resistance to at least two toxic ions) phenotypes were revealed, which indicates that this phenomenon is not restricted to bacteria originating from the heavily contaminated regions. This high number of heavy metal-resistant bacteria in the Antarctic region may be surprising; however, it is in agreement with the results of other studies (De Souza et al 2006Tomova et al 2014Tomova et al , 2015. Moreover, the high incidence of resistance to heavy metals suggests that bacteria are able to cope and/or adapt to the occurrence of "pollutants" even in low humanimpacted environments (Lo Giudice et al 2013).…”

“…Studies of extreme, polar environments characterized by a still limited anthropogenic influence (e.g., High Arctic or Antarctica) are of great importance, as they may reveal novel genes encoding heavy metal-resistance and metabolism mechanisms, and show the role of naturally occurring microorganisms in biogeochemical cycles. The results of several studies revealed that bacteria isolated from various Arctic and Antarctic environments show resistances to various toxic, antimicrobial agents, such as antibiotics and heavy metals (De Souza et al 2006Lo Giudice et al 2013;Mangano et al 2014;Moller et al 2014;Tomova et al 2014;Perron et al 2015;Rahman et al 2015;Tomova et al 2015;González-Aravena et al 2016;Rodriguez-Rojas et al 2016). However, overall knowledge on the resistome of polar bacteria is still rather limited, and the lack of a systematic approach, combining chemical, microbiological, and molecular analyses, is apparent.…”

Antimicrobial activity and resistance to heavy metals and antibiotics of heterotrophic bacteria isolated from sediment and soil samples collected from two Antarctic islands

“…Both kinds of resistance are becoming a global phenomenon, with resistant bacteria that are ubiquitous and have been detected in Antarctic seawater (De Souza et al 2006). As suggested by Shruti et al (2012), the varying response of the tested bacteria to the heavy metals may be due to the differences in their cell-wall composition or to variations in resistance mechanisms.…”

“…Toxic compounds such as heavy metals, antibiotics, pesticides and other persistent pollutants can be transferred to the Antarctic continent through natural processes by mass flow in the atmosphere and water, improper disposal practices and/or incineration of wastes produced at research stations (De Souza et al 2006;Corsolini 2009;Lo Giudice et al 2013). In the Antarctic environment, the reduced growth rates of organisms due to the low temperature promote high concentrations of potential contaminants in the Antarctic biota (Grotti et al 2008;Mangano et al 2014).…”

Bacterial Isolates of Marine Coast as Commercial Producer of Protease

“…The metal accumulating (Cu, Cd, Ni, Vd) property of some marine bacteria make them potential sources for bioremediation (De et al, 2006;Miranda and Rojas, 2006). Bacterial isolates from marine waters demonstrated varying degrees of resistance to antibiotics like Chloramphenicol, ampicillin, streptomycin, tetracycline and kanamycin (Manivasagan et al, 2011;Souza et al, 2006). Certain bacterial isolates from marine coast of West Bengal have already been isolated and characterized.…”