Introduction: Bacterial isolates and control strains stocking is an integral part of clinical microbiology laboratories. This is an essential step in maintaining quality. Preserving the strains without altering the character is an essentiality. There are different stock culture preparations studied in past showing varied level of performance. Aim: To evaluate the performance in terms of longevity and phenotypic character preservation of Peptone Glycerol Broth (PGB) in comparison to Brucella Glycerol Broth (BGB) and Skim Milk (SKM). Materials and Methods: The present study was a prospective analytical study. Three quality control strains and seven clinical isolates with different types of resistance were stocked in triplicates with cryobead based peptone broth with 15% glycerol, Brucella Broth (BB) with 15% glycerol and 10% SKM and stored at -80°C. Isolates were revived in monthly pattern, quarterly pattern and once after 10 months to assess the variations in viability and loss of phenotypic properties arising out of repeated freeze thaw and contaminations. Viability was assessed by time taken to produce observable confluent growth on revival. Metabolic characters and antibiotic susceptibility testing were compared before and after stock revival at intervals. Results: The phenotypic characters like metabolic features and antibiotic susceptibility were preserved with all three preparations both with repeated freeze thaw and single freeze thaw at the end of 10 months. PGB and BGB had a 100% revival rate of stored isolates with a confluent growth at 24 hours in comparison to 93.56% with SKM. Conclusion: Cryobead preparation of peptone broth-15% glycerol can be used as an effective preparation for stock culture maintenance of non-fastidious bacteria and yeast.

Klebsiella is a pathogen that causes a significantly high number of community-acquired and hospital-acquired infections, with infections being one of the leading causes of death in ICU patients worldwide due to increasing antibiotic-resistance and a lack of therapeutic options. A total of 230 Klebsiella spp. were collected from various clinical samples. After initial identification, the drug-resistant strain was subjected to standard Clinical Laboratory and Standards Institute methods such as Kirby–Bauer disc diffusion. All isolates were screened and confirmed for ESBL/AmpC β-lactamase/carbapenemase production. The isolated Klebsiella spp. were found to be K. pneumonia (89%), K. oxytoca (6.5%), and K. aerogenes (4.5%). Among the 230 isolates, 80 (34.7%) isolates were found to be ESBL producers via screening; of these, 53 (23.5%) were verified by a confirmatory test. Moreover, 115 isolates (50%) were screened as AmpC producers; of these, 23 isolates (10%) were verified by a confirmatory test. Carbapenemase producers accounted for 69 (30%) isolates, identified by screening; 25 (10.86%) were verified by a confirmatory test. ESBL producers accounted for the majority of Klebsiella spp. isolates, followed by carbapenem and AmpC producing strains.