Cockroach-Associated Food-Borne Bacterial Pathogens from Some Hospitals and Food Handling Establishment in Addis Ababa
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Date
2004-06
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Addis Ababa University
Abstract
A study was carried out to determine the role of cockroaches as reservoirs and vectors
of food-borne bacterial pathogens in some hospitals and food handling establishments
in Addis Ababa. A total of 1600 adult cockroaches were captured aseptically from eight
study sites between December 2002 and June 2003, and all were identified as Blattella
germanica. Ten cockroaches were pulled as one sample from each of the eight study
areas and killed with chloroform. Using selective media, their external surface wash and
internal (gut) homogenates, after adequate decontamination of the extemal surface,
were culturally examined for the presence of Salmonella, Shigella, Escherichia coli
0157:H7, Staphylococcus aureus and Bacillus cereus. We have also initiated challenge
studies to evaluate survival and excretion of Salmonella B, Shigella B, and
Staphylococcus aureus in B. germanica following ingestion of 10 6 CFU/g of
contaminated food. In the process of isolation and identification of the test pathogens,
12 Salmonella spp., 2 Shigella B, 2 E. coli 0157, 17 S. aureus and 25 B. cereus isolates
were made. Furthermore, most of the isolates were resistant to two or more
antimicrobial drugs in a susceptibility test. In the challenge experiment, cultural
examination of fecal pellets showed that Salmonella and S. aureus could be excreted
for 35 and 14 days post infection, respectively. However, culture examination of fecal
pellets of Shigella B infected cockroaches failed to yield the bacterium for 30 days post
infection. These results indicate that cockroaches (B. germanica) are the possible
reservoirs and vectors of multi-drug resistant food-borne pathogens in hospitals and
food-catering areas that may be responsible for nosocomial and community acquired
infections. Hence, there is a need to implement effective cockroach controlling programs focusing on hygiene. Continuous surveillance and rational use of antimicrobial
drugs are also required in order to minimize the emergence and spread of drug resistant
pathogenic bacteria by cockroaches. Further work is essential to establish the natural
transmission of human food-bome diseases by cockroaches
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Biology