# Results from the Survey of Antibiotic Resistance (SOAR) 2018–21 in India: data based on CLSI, EUCAST (dose-specific) and pharmacokinetic/pharmacodynamic (PK/PD) breakpoints

## TL;DR

This study analyzed antibiotic resistance in respiratory tract infection bacteria from India using different testing methods.

## Contribution

The paper compares antibiotic susceptibility results using CLSI, EUCAST, and PK/PD breakpoints for first-line drugs in India.

## Key findings

- High-dose ceftriaxone and moxifloxacin showed strong activity against Streptococcus pneumoniae.
- Cefdinir and second-generation cephalosporins had lower effectiveness against the studied bacteria.
- Ceftriaxone was the only drug effective against both Streptococcus pneumoniae and Haemophilus influenzae.

## Abstract

Antibiotic susceptibility determination of community-acquired respiratory tract infection (CA-RTI) isolates of Streptococcus pneumoniae and Haemophilus influenzae were collected from India (2018–21).

MICs were determined by CLSI broth microdilution; susceptibility data were interpreted using CLSI, EUCAST and pharmacokinetic/pharmacodynamic (PK/PD) breakpoints.

S. pneumoniae (n = 177) and H. influenzae (n = 171) isolates were collected from four hospital laboratories and two private laboratories in India. Only 41.2% pneumococci were penicillin susceptible by CLSI oral/EUCAST low-dose breakpoints, but 94.4% were susceptible by EUCAST high-dose/CLSI IV breakpoints. Good activity (≥89.8%, CLSI or PK/PD breakpoints) was observed for amoxicillin, amoxicillin/clavulanic acid, cefotaxime, ceftriaxone, levofloxacin, and moxifloxacin. Cefdinir and second-generation cephalosporins were less active (27.7%–64.4%). Tetracyclines, macrolides and trimethoprim/sulfamethoxazole showed poor activity (18.6%–31.1%). EUCAST breakpoints indicated >90% susceptibility to high-dose ceftriaxone and penicillin, moxifloxacin and high-dose levofloxacin. Lower susceptibility to other cephalosporins and aminopenicillins was observed with EUCAST versus CLSI or PK/PD breakpoints. Most H. influenzae isolates (91.8%) were β-lactamase negative; 13 and 5 were β-lactamase-negative ampicillin-resistant following EUCAST and CLSI criteria, respectively. Antibiotic susceptibility was ≥84.8% (CLSI) for all antibiotics except trimethoprim/sulfamethoxazole (23.4%). Susceptibility by EUCAST was similar, except for cefuroxime (oral) with no susceptible isolates versus 95.3% by CLSI and ≤29.8% versus ≥85.4% for fluoroquinolones.

Some therapeutic options against S. pneumoniae and H. influenzae from CA-RTI in India remain, but only ceftriaxone covers both bacterial species using both guidelines. Continued surveillance of antibiotic susceptibility is important to monitor changes and trends in susceptibilities and for guiding empiric therapy of CA-RTIs.