Key Themes and Findings:
Dominant Organisms and Specimen Distribution:
- Enterobacterales: The most frequently isolated group of organisms across all specimens. They make up a significant proportion of isolates, particularly in blood, urine, and lower respiratory tract (LRT) samples. Specifically, Enterobacterales, excluding Salmonella and Shigella, accounted for 46.3% of all positive cultures. Escherichia coli and Klebsiella pneumoniae are frequently observed Enterobacterales.
- Non-Fermenting Gram-Negative Bacilli (NFGNB): A significant proportion of isolates, especially in LRT samples. Acinetobacter baumannii and Pseudomonas aeruginosa are the predominant NFGNB. NFGNB accounted for 25% of all positive cultures.
- Staphylococcus aureus and Coagulase-Negative Staphylococci (CoNS): Common, particularly in blood and superficial infections. Staphylococcus haemolyticus and Staphylococcus epidermidis are also found in significant numbers.
- Enterococci: Significant presence in urine and deep infections, with Enterococcus faecalis being the most common species.
- Fungi: Candida species are frequently isolated, predominantly from blood samples. Candida tropicalis and Candida albicans are most common, with the concerning presence of Candida auris. Fungal isolates made up 2.81% of isolates.
- Diarrheal Pathogens: Predominantly isolated from faecal specimens.
- Specific Specimen Observations:
- Blood: Staphylococcus hominis, Salmonella Typhi, Staphylococcus spp. are the top isolates.
- LRT: Stenotrophomonas maltophilia, Klebsiella spp., Proteus mirabilis and Serratia marcescens are frequent.
- Superficial Infection: Proteus mirabilis and Morganella morganii are notable.
- Deep Infection: Proteus mirabilis and Enterococcus spp. are common.
- Faeces: A diverse range of organisms including Salmonella spp., Aeromonas spp., diarrheagenic E. coli, Vibrio cholerae, and Shigella species.
Antimicrobial Resistance Trends:
- Enterobacterales:
- Significant resistance to commonly used antibiotics such as ciprofloxacin.
- Carbapenem resistance is observed, with imipenem and meropenem showing reduced susceptibility.
- E. coli and K. pneumoniae demonstrate varying levels of resistance to multiple antibiotic classes across different centres.
- Fosfomycin shows relatively good susceptibility rates for Enterobacterales.
- Salmonella Typhi:
- High susceptibility to ampicillin, azithromycin, cefixime, ceftriaxone, and chloramphenicol.
- Alarmingly high resistance to ciprofloxacin with some reduction in susceptibility to levofloxacin.
- Shigella flexneri:
- Significant resistance to ampicillin, with moderate resistance to trimethoprim-sulfamethoxazole
- Stenotrophomonas maltophilia:
- Generally susceptible to minocycline and trimethoprim-sulfamethoxazole.
- Pseudomonas aeruginosa: Demonstrates carbapenem resistance with presence of metallo beta-lactamase genes such as NDM and VIM
- Burkholderia cepacia: High rates of carbapenem resistance are seen with the presence of OXA23 & NDM resistance determinants.
- Staphylococcus aureus:
- High methicillin resistance (MRSA) rates, with variations across different regions.
- Good susceptibility to vancomycin and teicoplanin.
- Resistance to ciprofloxacin is high.
- Enterococci:
- High rates of resistance to vancomycin with the presence of the vanA gene.
- Candida species:
- Generally susceptible to anidulafungin, caspofungin, micafungin, voriconazole.
- Candida auris has shown a significant resistance to fluconazole.
- Candida glabrata has also shown resistance to fluconazole.
Molecular Mechanisms of Resistance:
- E. coli and K. pneumoniae: Resistance is often associated with specific genes:
- blaNDM, blaOXA-48, blaCTX-M-15, blaTEM, blaSHV are prevalent.
- The distribution of these genes varies significantly across different regional centres.
- Salmonella spp.:
- Resistance to fluoroquinolones is associated with mutations in gyrA and parC genes.
- Pseudomonas aeruginosa: Carbapenem resistance is driven by metallo beta-lactamase such as blaNDM and blaVIM
- Burkholderia cepacia: Resistance is driven by blaOXA23 and blaNDM genes.
- Staphylococcus aureus:
- hVISA (heteroresistant vancomycin-intermediate S. aureus) is associated with amino acid substitutions in graS, mprF and vraR genes.
- Mupirocin resistance was found to be due to mupA genes.
Trends Over Time:
- Enterococcus species: Show a fluctuation in yearly isolation trends.
- “Year-2022 (%) 6965/ 107053 (6.5)“
- “Year-2023 (%) 6999/ 99492 (7)“
- Candida species Show a fluctuation in yearly isolation trends.
- “Year-2020 (%) 2403/ 108465 (2.2)“
- “Year-2023 (%) 2493/ 99492 (2.5)“
- Salmonella Typhi: Ceftriaxone MIC shows a fluctuating trend over the years. Azithromycin MIC also shows variability over the years.
- The MIC50 and MIC90 for azithromycin in S. Typhi have varied over time.
- Aeromonas spp.: Fluctuating rates of resistance to cefixime.
- Shigella flexneri: Fluctuating rates of susceptibility to ampicillin and trimethoprim-sulfamethoxazole.
Regional Variations:
* The data reveals notable differences in the prevalence of specific organisms and resistance patterns across different surveillance centres, indicating the need for region-specific interventions.
Implications:
- The high prevalence of resistant organisms highlights the urgent need for antibiotic stewardship programs and infection prevention control measures.
- The data on molecular mechanisms of resistance can inform the development of new diagnostic tools and therapeutic strategies.
- The regional variations emphasize the importance of tailoring public health interventions to the local context.
Recommendations:
- Strengthen surveillance efforts to monitor the changing trends in AMR.
- Implement robust antibiotic stewardship programs in hospitals and communities.
- Promote research and development of new antibiotics and alternative therapies.
- Enhance infection prevention and control practices to reduce the spread of resistant organisms.
- Educate healthcare providers and the public about the rational use of antibiotics.
Conclusion:
The ICMR’s 2023 AMR Surveillance Network data highlights a complex and concerning scenario of antibiotic resistance in India. The findings underscore the need for a concerted, multi-pronged approach to tackle this global health threat. Continued surveillance, informed by molecular analysis, will be crucial for guiding effective strategies to mitigate the impact of AMR.
