Transient gut retention and persistence of Salmonella through metamorphosis in the lesser mealworm, Alphitobius diaperinus (Coleoptera: Tenebrionidae)

Abstract

Aims: This study was undertaken to determine the retention of Salmonella through Alphitobius diaperinus metamorphosis and its contribution, through defecation, to external contamination. Methods and Results: Insects were exposed to a tagged Salmonella enterica and evaluated for external elimination. (i) Each day for 3 weeks, a filter collected frass from a restrained insect for analysis. (ii) Exposed larvae in a closed container were followed through pupation, and newly emerged adults were examined for their retention of marker bacteria. Conclusions: Exposed adults and larvae produced Salmonella‐positive frass for an average of 8 days, ranging from 6 to 11 days and 6 to 12 days, respectively. Nineteen per cent of the larvae carried Salmonella through metamorphosis and eclosion, with 5% of the pupal exuviae being positive as well. Significance and Impact of the Study: Many sources of foodborne pathogens within the poultry production facilities, including reservoir populations, currently go unrecognized. This diminishes the ability of producers to mitigate the transfer of pathogens between animals, humans and the environment. Poultry management standards accept the reutilization of litter. Alphitobius diaperinus survive between flock rotations on the reutilized litter, and it was demonstrated in this study that the Salmonella they carry can survive with them.

The lesser mealworm Alphitobius diaperinus: a noxious pest or a promising nutrient source?

“…Adults and larvae of A. diaperinus can retain Salmonella for an average of 8 days, whereas Salmonella has the capacity to persist through the metamorphic changes, as newly emerged adults have been found positive to Salmonella , following exposure of the larvae to the bacterium (Crippen et al . ). Moreover, a threshold level of bacterial load may be required to facilitate transmission between A. diaperinus and its environment (Crippen et al .…”

“…Recently, the use of GFP‐tagged marker bacteria has elucidated the mechanisms involved in the vectoring and transmission of Salmonella and subsequently the infection of poultry flocks within poultry production facilities (Crippen et al . , ). For instance, Crippen et al .…”

Occurrence and antimicrobial resistance of Salmonella serotypes isolates recovered from poultry of Western Paran, Brazil

“…So the control of dissemination of Salmonella is dependent on the control of transmission sources (Frederick and Huda, 2011). One reason that may explain the presence of S. enteritidis in poultry refers to the high incidence of mealworm (Alphitobius diaperinus) considered a pest and transmission vector of Salmonella (Crippen et al, 2012). Therefore, the mealworm elimination in broilers is considered an important measure for controlling the salmonellosis in poultry (Leffer et al, 2010).…”

Insects as Food for Insectivores

“…both externally and internally ( Crippen et al, 2009). Additionally, Salmonella could be detected in newly emerged adult beetles from infected larvae, suggesting some bacteria are carried through metamorphosis (Crippen et al, 2012). Because several species of grain beetles (Tenebrio sp and Z. morio) are commonly used as feeder insects, it seems likely that these species could serve as a vector of Salmonella spp.…”