Sterilisation and Disinfection

A 32-year-old female surgical nurse presents to occupational health with a history of recurrent needle-stick injuries over the past 6 months. The hospital's infection control committee is reviewing sterilization protocols for reusable surgical instruments in the operating theatre. During an audit, they discover that several instrument trays are being processed through a steam autoclave at 121°C for only 10 minutes at 15 psi, despite manufacturer recommendations of 15–20 minutes. Three weeks later, a post-operative patient develops a surgical site infection with Mycobacterium tuberculosis. Which sterilization parameter was most likely compromised, leading to survival of this pathogen?

A 28-year-old male patient undergoes an emergency laparotomy for a perforated duodenal ulcer at a rural hospital in Uttar Pradesh. Post-operatively, he develops a surgical site infection with Clostridium difficile. The hospital's central sterile supply department (CSSD) uses a low-temperature hydrogen peroxide gas plasma sterilizer for heat-sensitive endoscopic instruments. However, an audit reveals that the sterilizer's chamber was not properly vented after the sterilization cycle, and residual hydrogen peroxide vapor remained in the instrument packaging. The surgeon used the instruments without allowing adequate aeration time. Which property of hydrogen peroxide gas plasma sterilization was not respected, increasing the risk of tissue toxicity and instrument contamination?

A clinical laboratory in Delhi performs routine disinfection of work surfaces and equipment using a quaternary ammonium compound (QAC). The laboratory director suspects that the disinfectant solution may have lost potency due to prolonged storage. Which investigation would be most appropriate to assess the antimicrobial efficacy of the disinfectant solution?

A hospital microbiology laboratory receives a batch of surgical instruments that must be sterilized before use in the operating theatre. The instruments include stainless steel forceps, rubber tubing, and heat-sensitive plastic components. Which investigation or test would be most appropriate to verify the efficacy of the sterilization process employed?

A 55-year-old surgeon at a tertiary care hospital requires sterilisation of reusable surgical instruments contaminated with Mycobacterium tuberculosis. Which of the following is the drug of choice for chemical sterilisation in this scenario?