Biofilm colonization of Mycobacterium abscessus: New threat in hospital-acquired surgical site infection.

INTRODUCTION: Rapidly growing non-tuberculous mycobacteria (NTM) are hazardous cause of post-operative soft tissue infection leading to nosocomial outbreaks following various surgical procedures, especially laparoscopic surgeries using heat sensitive, non-autoclavable surgical instruments. METHODOLOGY: Surgery department of our hospital noticed increase in rate of post-laparoscopic abdominal port site infection (PSI) and informed the Microbiology Department. A prospective investigational study of defined cases with the aim of source tracing and formulation of infection control measures was initiated. Pus or wound scrapings were collected and processed for aerobic, anaerobic bacteria and Mycobacterium, both by staining and culture. Environmental samples were collected from laparoscopic instruments, and different parts of operation theatre (OT). Mycobacterial isolates were speciated by line probe assay. All the cases were treated with clarithromycin and ofloxacin±amikacin. RESULTS: Among 15 cases of PSI, 11 patients had undergone laparoscopic cholecystectomy, 3 had laparoscopic mesh hernioplasty and one had laparoscopic orchidopexy. Of the 13 pus/discharge specimens examined, 11 revealed growth of NTM. All the isolates were identified as Mycobacterium abscessus by line probe assay. Scraping of biofilm from the disinfectant tray also produced growth of the same organism. Plastic trays used for disinfectants were replaced with metal trays and instructed to do mechanical scrubbing before autoclaving at regular interval. No similar PSI cases were notified after those measures were taken, till date. CONCLUSIONS: This study has shown the need of culture and identification of pathogens causing persistent post surgical wound infections and illuminated importance of rapid source tracing in resource constraint situation which could control outbreak.

Port-site infections by nontuberculous mycobacterium: A retrospective clinico-microbiological study.

BACKGROUND: Port-site infection (PSI) is a prevailing, chronic, nagging, treatment refractory complication of laparoscopic surgery (LS). It neutralizes the advantages of minimally invasive surgery and increases morbidity, treatment cost of patient, leading to loss of confidence on operating surgeon. PSIs are preventable with appropriate preoperative, intraoperative, and postoperative measures. Atypical mycobacterium is most commonly associated with nonhealing postlaparoscopic wound infections, causing outbreaks or sporadic cases worldwide. PURPOSE: We retrospectively studied the occurrence of nontuberculous mycobacterium (NTM) from PSIs following LS that did not respond to antibiotics used for pyogenic infections and having sterile routine aerobic cultures and their antimicrobial susceptibility pattern to guide proper management. METHODS: The study was done in a tertiary care hospital of Eastern India over a 1-year period which included PSI cases with delayed onset not responding to antibiotics, following different types of LS. Pus/discharge from 32 patients was collected and examined for isolation and identification of the causative agents. Gram stain and Ziehl-Neelsen staining methods were used for direct examination. Culture media included blood agar, Robertson's cooked meat broth, MacConkey agar, and Lowenstein-Jensen medium. Isolates from the cases were identified using biochemical tests or molecular methods and studied the antimicrobial susceptibility pattern by the standard microbiologic procedures. RESULTS: Mycobacterium abscessus (13) and Mycobacterium fortuitum (2) were isolated from 15 serosanguinous drainage obtained from 32 cases by routine microbiological techniques. All isolates analyzed for antimicrobial susceptibility pattern were highly sensitive to clarithromycin (93.3%), amikacin (93.3%), and imipenem (80%) but were variable to ciprofloxacin, ofloxacin, and linezolid. CONCLUSIONS: Our present study shows frequent association of NTM with laparoscopic port-site nonhealing chronic infection or wound dehiscence. Although direct microscopy can give us a clue to diagnosis, culture isolation is required for speciation and antimicrobial susceptibility testing, which helps formulate therapeutic regimen.