High prevalence of antibiotic-resistant and metal-tolerant cultivable bacteria in remote glacier environment

Wasim Sajjad; Barkat Ali; Hewen Niu; Nikhat Ilahi; Muhammad Rafiq; Ali Bahadur; Abhishek Banerjee; Shichang Kang

doi:10.1016/j.envres.2023.117444

High prevalence of antibiotic-resistant and metal-tolerant cultivable bacteria in remote glacier environment

Environ Res. 2023 Dec 15;239(Pt 2):117444. doi: 10.1016/j.envres.2023.117444. Epub 2023 Oct 18.

Authors

Wasim Sajjad¹, Barkat Ali¹, Hewen Niu², Nikhat Ilahi³, Muhammad Rafiq⁴, Ali Bahadur¹, Abhishek Banerjee¹, Shichang Kang⁵

Affiliations

¹ State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China.
² State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China; National Field Science Observation and Research Station of Yulong Snow Mountain Cryosphere and Sustainable Development, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China.
³ State Key Laboratory of Herbage Improvement and Grassland Agro-Ecosystems, College of Ecology, Lanzhou University, Lanzhou, 730000, China.
⁴ Department of Microbiology, Faculty of Life Sciences and Informatics, Engineering and Management Sciences, Balochistan University of Information Technology, Quetta, Pakistan.
⁵ State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China. Electronic address: shichang.kang@lzb.ac.cn.

PMID: 37858689
DOI: 10.1016/j.envres.2023.117444

Abstract

Studies of antibiotic-resistant bacteria (ARB) have mainly originated from anthropic-influenced environments, with limited information from pristine environments. Remote cold environments are major reservoirs of ARB and have been determined in polar regions; however, their abundance in non-polar cold habitats is underexplored. This study evaluated antibiotics and metals resistance profiles, prevalence of antibiotic resistance genes (ARGs) and metals tolerance genes (MTGs) in 38 ARB isolated from the glacier debris and meltwater from Baishui Glacier No 1, China. Molecular identification displayed Proteobacteria (39.3%) predominant in debris, while meltwater was dominated by Actinobacteria (30%) and Proteobacteria (30%). Bacterial isolates exhibited multiple antibiotic resistance index values > 0.2. Gram-negative bacteria displayed higher resistance to antibiotics and metals than Gram-positive. PCR amplification exhibited distinct ARGs in bacteria dominated by β-lactam genes bla_CTX-M (21.1-71.1%), bla_ACC (21.1-60.5%), tetracycline-resistant gene tetA (21.1-60.5%), and sulfonamide-resistant gene sulI (18.4-52.6%). Moreover, different MTGs were reported in bacterial isolates, including mercury-resistant merA (21.1-63.2%), copper-resistant copB (18.4-57.9%), chromium-resistant chrA (15.8-44.7%) and arsenic-resistant arsB (10.5-44.7%). This highlights the co-selection and co-occurrence of MTGs and ARGs in remote glacier environments. Different bacteria shared same ARGs, signifying horizontal gene transfer between species. Strong positive correlation among ARGs and MTGs was reported. Metals tolerance range exhibited that Gram-negative and Gram-positive bacteria clustered distinctly. Gram-negative bacteria were significantly tolerant to metals. Amino acid sequences of bla_ACC,bla_CTX-M,bla_SHV,bla_ampC,qnrA, sulI, tetA and bla_TEM revealed variations. This study presents promising ARB, harboring ARGs with variations in amino acid sequences, highlighting the need to assess the transcriptome study of glacier bacteria conferring ARGs and MTGs.

Keywords: Antibiotic resistant genes; Antibiotic-resistant bacteria; Baishui glacier; Metals tolerance genes; Remote glacier environment.

MeSH terms

Angiotensin Receptor Antagonists
Angiotensin-Converting Enzyme Inhibitors
Anti-Bacterial Agents / analysis
Anti-Bacterial Agents / pharmacology
Bacteria
Drug Resistance, Bacterial / genetics
Genes, Bacterial*
Gram-Negative Bacteria / genetics
Ice Cover* / microbiology
Metals / analysis
Prevalence

Substances

Angiotensin Receptor Antagonists
Angiotensin-Converting Enzyme Inhibitors
Anti-Bacterial Agents
Metals