Cockroaches as vectors of bacteria in hospital environments.

Abstract

Cockroaches have become one of the most common pests due to their wide distribution in human dwellings, kitchens, food outlets and the hospital. In hospitals their wide abundancy may be related to poor sanitary conditions, plenty of food sources, environments which are unhygienic and moist shady places. This study was carried out to evaluate the microbial fauna of cockroaches in a hospital environment as proxy to Health acquired infections. Two different species of cockroaches Periplaneta americana and Blatella germanica were collected in the canteen and the main kitchen of a hospital in Gweru. The former and the latter were cultured using standard procedures and antibiotic susceptibility tests were done. Microbial isolation was done for the two species of cockroaches by growing saline suspensions of the cockroach samples onto selective and differential media. Bacterial isolates were identified by biochemical tests. Medically important microorganisms were isolated from their external surface and their internal surface. These bacteria were Proteus spp, Klebsiella spp, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus. The susceptibilities of Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella spp, Escherichia coli, and Proteus species to 6 antibiotics were tested. Most of the gram negative bacteria were resistant to amoxicillin, Augmentin and streptomycin and sensitive to ciprofloxacin and chloramphenicol. Enumeration was also conducted using saline suspensions of the internal and external washings and the range from P. americana to B. germanica from external washings were 3.60 ×104 to 3.20×104 cfu/ml respectively and for the internal washings 3.40 ×104 to 3.23 ×104 cfu/ml respectively .The data collected was subjected to Two-way analysis of variance (ANOVA) using SPSS version 21. Two-way Anova results showed that there is no statistically significant interaction between type of washings and type of species in influencing the mean total bacterial count (p>0.05). Two-way Anova data also revealed that the mean total bacterial count of periplaneta americana was significantly higher than that of blatella germanica (p<0.05). In conclusion, all cockroaches harboured pathogenic bacteria with multidrug resistance, this means that cockroaches play a potential role in the epidemiology of nosocomial infections in this hospital.