Isolation and Identification Enterobacter asburiae from Consumed Powdered Infant Formula Milk (PIF) in the Neonatal Intensive Care Unit (NICU)

Enterobacter asburiae (E. asburiae) is a facultative anaerobic, non-spore-forming gram-negative rod-shaped bacterium belonging to the family of Enterobacteriaceae. It is an opportunistic pathogen that its strains are isolated from a variety of clinical and environmental specimens. Since powdered infant formula milk (PIF) is not a sterile product, it is an excellent medium for bacterial growth. The aim of this study was to isolate and identify E. asburiae from PIF in the neonatal intensive care unit (NICU) and determine antimicrobial susceptibility patterns of this bacterium. A total 125 PIF samples were purchased from drug stores between June 2011 to March 2012. E. asburiae was isolated according to FDA method. For final confirmation, biochemical tests embedded in the API-20E system were used. The drug susceptibility test was performed using the disc diffusion method according to CLSI recommendations. Out of the 125 PIF samples investigated, 2 (1.6%) samples were positive for E. asburiae. All isolated strains were uniformly susceptible to aztreonam, cefotaxim, amikacin, streptomycin, nalidixic acid, meropenem, tetracycline, ceftazidime, and colistin. Variable susceptibility was seen to the some antimicrobial agents tested. Each country should categorize its own designed guidelines for the preparation and handling of PIF adapted to the local environment. Moreover, the pathogenesis of the E. asburiae in infants hospitalized in NICU and other groups such as immunosuppressed patients and HIV infected individuals is uncertain and requires further study.

Isolation, identification and antimicrobial susceptibility of Pantoea (Enterobacter) agglomerans isolated from consumed powdered infant formula milk (PIF) in NICU ward: First report from Iran

BACKGROUND AND OBJECTIVES

Pantoea agglomerans is a Gram-negative rod in the Enterobacteriaceae family. It is reported as both commensal and opportunistic pathogen of animals and humans. This organism is potential candidates as powdered infant milk formula-borne opportunistic pathogen. The aim of our study was to perform isolation, identification and antimicrobial susceptibility pattern of Pantoea (Enterobacter) agglomerans strains isolated from consumed powdered infant formula milk (PIF) in NICU ward.

MATERIALS AND METHODS

A of total 125 powdered infant formula milk (PIF) samples were purchased from hospital drug stores between June 2011 to March 2012. P. agglomerans was isolated according to FDA method. For final confirmation, biochemical tests embedded in the API-20E system were used. The drug susceptibility test was performed using the disc diffusion method according to CLSI guidelines.

RESULTS

Out of the 125 samples investigated, 8 (6.4%) samples were positive for P. agglomerans and these were uniformly susceptible to tigecycline, chloramphenicol, cefepime, levofloxacin, minocycline and colistin. Fifty percent of isolates were resistant to cefotaxime, moxifloxacin, cotrimoxazole and ticarcillin.

CONCLUSION

Controlling the primary populations of P. agglomerans during the PIF production process and preventing post processing contamination, by using suitable microbiological guidelines, is accessible. Sanitary practices for the preparation of infant formula in both the home and hospitals should be carefully controlled.