Teicoplanin

Antimicrobial susceptibility tests of the clinical isolates against different antimicrobials were performed in Müller–Hinton agar (MHA) using the standard disk diffusion technique (modified Kirby–Bauer method) and interpreted as per Clinical and Laboratory Standards Institute guidelines.16 The following antimicrobial agents were tested: ampicillin (10 μg), cefoxitin (30 μg), ciprofloxacin (5 μg), chloramphenicol (30 μg), clindamycin (2 μg), cotrimoxazole (25 μg), doxycycline (30 μg), erythromycin (15 μg), gentamicin (10 μg), minocycline (30 μg), rifampicin (5 μg), teicoplanin (30 μg), tetracycline (30 μg) and vancomycin (30 μg) (HiMedia Laboratories, Mumbai, Maharashtra, India). S. aureus ATCC 25923 was used as the control organism.
Isolates were considered multidrug resistant (MDR) based on the guidelines recommended by the joint initiative of the European Centre for Disease Prevention and Control (ECDC) and the Centers for Disease Control and Prevention (CDC).17 (link) According to those guidelines, the isolates showing non-susceptibility to at least one agent in three or more antimicrobial categories were identified as MDR.
S. aureus isolates showing positive D zone test were considered as resistant to clindamycin.

To isolate C. jejuni, the cecal content of commercial broiler chickens was collected and processed (Singh and Mallick, 2019 (link)). Processed samples were plated onto a blood Free Campylobacter Selectivity Agar Base medium (HiMedia, India) supplemented with CAT selective supplement (cefoperazone 8 mg/L, amphotericin 10 mg/L, and teicoplanin 4 mg/L) (HiMedia, India) and incubated for 36-48 h at 42°C. Colonies were examined for characteristic morphological appearance followed by biochemical analysis including catalase, oxidase, and hippurate hydrolysis test. Further, selected colonies were checked for the presence of 16S rRNA and other major genes encoding virulence factors (GEVFs), including hipO, cadF, ciaB genes.
The standard C. jejuni strain (NCTC 11168; Genbank ID: AL111168.1) was obtained through the NIH Biodefense and Emerging Infections Research Repository, NIAID, NIH: Campylobacter jejuni subsp. jejuni, Strain NCTC 11168, NR-126.

During the study period, 1290 patients were admitted in the PICU, out of which 1018 patients stayed >48 h. As calculated sample size was 196, convenient sampling was carried out to achieve the sample size. Rectal swabs were collected after 48 h of admission to PICU and inoculated onto bile esculin sodium azide agar containing 6mg/L vancomycin (Himedia laboratories, Mumbai, India).[5 (link)] Black/brown colonies were presumptively identified as Enterococcus and confirmed to species level based on Facklam and Collins standard biochemical tests.[24 (link)] Minimum inhibitory concentration (MIC) of vancomycin and teicoplanin was determined by agar dilution method for all the enterococcal isolates grown on BEA as per the Clinical and Laboratory Standard Institute guidelines.[25 ] MIC of ≥32 was considered as resistant to both vancomycin and teicoplanin. The antimicrobial susceptibility of the isolates to other antibiotics, namely, ampicillin, high-level gentamicin, tetracycline, and linezolid was also performed by Kirby-Bauer disc diffusion method.[26 ] Association of VRE colonization with demographic features of the patients and various risk factors for VRE colonization were assessed based on previous studies.

We performed antimicrobial susceptibility test of the isolates by the Kirby–Bauer method adhering to clinical and laboratory standard institute (CLSI) guidelines against following antimicrobial discs: amikacin (10 µg), cefalexin (30 µg), ceftriaxone (30 µg), ofloxacin (5 µg), vancomycin (30 µg), linezolid (30 µg), and teicoplanin (30 µg) (HiMedia, India). We checked the quality of all the discs by testing them against Staphylococcus aureus ATCC 25923 before use.