Abstract

The increasing trends of insect associated bacterial infection in humans are severely hampered by disparaging number of bacteria obtained with the culture-based technique. This study therefore determined how the analysis of the 16S rDNA sequences would compare in terms of precision and reliability to the most adoptable culture-based technique. Results obtained depict enhanced accuracy of  molecular technique over the cultural method as only 249 (69%) of the total isolates were correctly identified by the cultural method to represent a total of 114 (31%)  discrepant species while 100% correct identification was observed with the molecular technique. The most predominant of these bacterial isolates from both the external surfaces and the gut environment was Escherichia coli 43 (20.8%) and 24 (15.5%) respectively. The Gram positive organisms isolated were Staphylococcus aureus, Bacillus subtilis, Staphylococcus epidermidis, and Enterococcus faecalis with a prevalence rate of 8 (3.8%), 14 (6.7%), 8 (3.8%) and 9 (4.3%) from external surfaces and 2 (1.3%), 6 (3.9%), 2 (1.3%) and 7 (4.5%) from gut environment respectively. The least isolated organisms in the external surfaces were Serratia marscencens and Citrobacter werkmanii with a distribution rate of 3(1.4%) while Citrobacter freundii 2(1.3%) was the least isolated organism from cockroach gut environment. This study therefore showed that the molecular analysis of the 16S rDNA sequences is more efficient than culture-based technique for the identification of bacterial contaminants of cockroaches because occurrences of misidentification are very much abated by this method. 

Key words: Bacterial contaminants, Cockroaches (Periplaneta americana), cultural technique, molecular technique.