A survey on species and prevalence rate of bacterial agents isolated from cockroaches in three hospitals.

The presence of cockroaches has health implications, such as nosocomial infection, as the insects move freely from areas within and around hospitals that may harbor pathogenic organisms. The goals of the present study were to determine species of bacteria isolated from cockroaches found in three Tehran hospitals, and to determine distribution of potential vectors by species and sex. The study is descriptive laboratory research. A total of 305 cockroaches from three species were trapped and identified: Periplaneta americana (65.6%), Blatella germanica (12.1%), and Blatta orientalis (22.3%). From these potential vectors, 19 species of bacteria were isolated and identified. After transportation of cockroaches to the laboratory, separation of the whole-homogenized suspension of each species was carried out. Identification of the isolated bacteria was performed according to Burgey's Manual of Determinative Bacteriology, 9th Edition. The most common species of bacteria isolated from cockroaches were Escherichia coli, Streptococcus Group D, Bacillus spp., Klebsiella pneumoniae, and Proteus vulgaris. No statistical significance was found between sex and species of cockroach carrying bacteria (p > 0.05), but significance was found for sex in Citrobacter freundii, Staphylococcus aureus, and Streptococcus non-group A&B (p < 0.05).

Laboratory evaluation of dimethyl phthalate against Anopheles stephensi and Culex pipiens.

Two repellents includes Iranian and Merck dimethyl phthalate (DMP) were evaluated against Anopheles stephensi and Culex pipiens, using American Society for Testing and Material (ASTM) standard ED 951-83 procedure, a free choice method based on the variable dose-fixed time. Also a modified of ASTM method we used for determination of effective dosages of the repellents. In ASTM method there were no significant differences between the two repellents (Iranian and Merck's DMP) as indicated by the ED50 and ED95 values (p > 0.05). But, there were significant differences in repellent sensitivity between An. stephensi and Cx. pipiens at the ED95 level. In modified ASTM method there were no significant differences between the two repellents against An. stephensi, as indicated by the ED50 values (p > 0.05). But, there are significant differences between the two repellents against Cx. pipence based on ED50 value. Results of this study showed that the Iranian synthesized DMP has necessary potential and specificity to compare with Merck manufactured product.