New ICMR report highlights growing resistance in bacteria to antibiotics critical for human health

The Indian Council of Medical Research’s (ICMR) Antimicrobial Resistance Research and Surveillance Network has published its annual report for 2023, marking the seventh comprehensive review of antimicrobial resistance (AMR) trends in India, covering data from January to December 2023.

The report focused on commonly used antibiotics for treating diseases such as upper respiratory infections, fevers, diarrhoea, pneumonia, sepsis, community-acquired pneumonia and other bloodstream infections. These antibiotics were tested against bacteria such as Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Staphylococcus aureus, isolated from specimens collected in outpatient departments (OPD), wards and intensive care units (ICU).

The paper revealed an alarming trend of increasing antibiotic resistance and declining susceptibility of common pathogenic bacteria. The report is based on the analysis of 99,492 culture-positive isolates from various specimens, including blood, urine, superficial infections, the lower respiratory tract (LRT), deep infections, sterile sites and faeces. Twenty-one regional centres from across India, both public and private, contributed to the surveillance.

The isolates were tested for their susceptibility to a range of antibiotics, including amikacin (aminoglycoside), cefotaxime and ceftazidime (third-generation cephalosporins), ciprofloxacin and levofloxacin (fluoroquinolones), piperacillin-tazobactam, imipenem, meropenem (carbapenems) and colistin (a polymyxin).

These antibiotics are classified as Critically Important Antimicrobials (CIA) and Highest Priority Critically Important Antimicrobials (HPCIA) by the World Health Organization (WHO), underscoring the importance of their prudent use in human and animal health to preserve their efficacy.

For example, E coli was found to be the most persistent across OPD, ICU and ward settings. It showed poor susceptibility to cefotaxime, ceftazidime, ciprofloxacin and levofloxacin, with overall susceptibility rates of less than 20 per cent.

Susceptibility to most antibiotics has decreased over time, with piperacillin-tazobactam dropping from 56.8 per cent in 2017 to 42.4 per cent in 2023 and amikacin from 79.2 per cent to 68.2 per cent over the same period, the paper showed. The susceptibility of E coli to carbapenems has also notably declined, with imipenem falling from 81.4 per cent in 2017 to 62.7 per cent in 2023 and meropenem from 73.2 per cent to 66 per cent.

Similarly, Klebsiella pneumoniae exhibited reduced susceptibility, with piperacillin-tazobactam falling from 42.6 per cent to 26.5 per cent, imipenem from 58.5 per cent to 35.6 per cent and meropenem from 48 per cent to 37.6 per cent. Fluoroquinolone resistance also increased, with ciprofloxacin susceptibility dropping from 32 per cent to 17.1 per cent over seven years.

Pseudomonas aeruginosa also showed a gradual increase in resistance to carbapenems, with imipenem resistance rising from 26 per cent in 2017 to 38.5 per cent in 2023 and meropenem from 31.3 per cent to 34.5 per cent. Resistance to fluoroquinolones has similarly increased, with ciprofloxacin resistance rising from 26 per cent to 38.5 per cent and levofloxacin from 31.3 per cent to 34.5 per cent over the same period.

In addition, Salmonella typhi, which causes gastroenteritis (diarrhoea, vomiting, fever and abdominal cramps), showed over 95 per cent resistance to fluoroquinolones.

The data indicated a concerning rise in resistance to CIAs and HPCIAs, which are essential for treating serious human infections. Resistance rates among key bacterial pathogens, such as Escherichia coli, Klebsiella pneumoniae and Staphylococcus aureus, have increased significantly.

Overall, the report highlighted a troubling increase in antibiotic resistance and declining bacterial susceptibility, underscoring the need for stronger antibiotic stewardship measures.

Previously, a report by the Delhi-based think tank, Centre for Science and Environment (CSE), also highlighted the misuse of several antibiotics from these classes in food-producing animals in India.

CSE identified 27 types of CIAs from seven classes, including macrolides, ketolides, third-generation cephalosporins and fluoroquinolones, being used in dairy, poultry and aquaculture for both therapeutic and non-therapeutic purposes. The report emphasised the need to conserve critically important antibiotics for human health.