Study of Population dynamics of cockroaches collected from Lahore with resistance patterns of their isolated microbial fauna

Abstract

Cockroaches are one of the most important pests in urban communities and are risky for human health because they play an important role in transmitting different diseases either mechanically or occasionally biologically. Environmental and sanitary conditions associated with demographic and socio-economic settings of an area could contribute to the prevalence of disease pathogens carried by cockroaches. The present study was aimed to determine taxonomical identification and diversity of cockroaches in hospitals and houses in Lahore, Pakistan and to evaluate the role of cockroaches in transmission of important disease pathogens by using microbial screening of outer surface and digestive tract. Resistance and susceptibility to antimicrobials and disinfectants was also investigated, followed by quantitative and qualitative analysis of total bacterial protein. Four species of cockroaches (P. americana, B. germanica, B. orientalis and B. lateralis) were identified in this study. B. germanica was found to be the most dominant indoors species with highest diversity indices followed by P. americana. Species diversity was highest in July–September, 2013 with highest Simpson index of diversity and Shannon index as well. Population index of B. germanica for hospitals was double than that of residential areas. Houses and hospitals were highly infested with P. americana and B. germanica as compared to offices, shopping malls/ departmental stores and universities. Whereas B. orientalis was commonly found in houses, institutes/universities followed by hospitals, while B. lateralis was common in institutes/ universities, houses and offices with basements and gardens. P. americana was found higher in all trimesters (mean 1179.50 + 351.77) and the analysis of variance revealed a significant difference between the groups (F(3,4)=9.65, P=0.005). Significant correlation was found among changes in temperature and abundance of P. americana in study area (Pearson correlation, r= 0.904, P= 0.04). Similarly temperature showed positive correlation with population of B. germanica (r= 0.958, P= 0.021) and B. orientalis (r= 0.987, P= 0.007). During the study, all cockroaches were found to be infected with at least one bacterium. The most common bacterium isolated from external surface of cockroaches was E. coli (10.31%), followed by S. aureus (10.09%), while P. aeruginosa (19.96%) was isolated from internal gut tract of cockroaches, followed by P. vulgaris (16.08%). Among hospitals the highest in external bacterial infection was observed on P. americana in Punjab Institute of Cardiology (PIC) (75.6%) while ii highest internal bacterial infection was observed in Sheikh Zaid Hospital (SZH) (30.8%). Same trend was observed for bacterial isolation from B. germanica in hospitals. Among houses highest external bacterial infection for P. americana (55.9%) and B. germanica (52%) was observed in samples collected from Shalamar- II. However, highest internal contamination (25.8%) for P. americana was observed in Mughalpura-I locality while highest internal infection (28.8%) for B. germanica was Model town-3 houses. Jaccard’s index of similarity was highest (0.3125) in houses while Bray-Curtis index of dissimilarity was highest for hospital (0.2174). The highest Shannon-Wiener’s diversity index value was found for Punjab Institute of Cardiology (2.610632). All cockroaches had also carried one or more species of medically important mould on their external surface. In this study the most common mold isolated and identified from First Fungal Culture Bank of Pakistan were A. oryzae (84%) and A. flavus (75%) while least common was G. candidum (22%). Cockroaches collected from Shadman-1, Johar town-1 and Shalamar-2 showed relatively high fungal prevalence. P. americana harboured more parasites as compared to B. germanica in both environment. E. coli protozoan was found as the most prevalent followed by E. vermiculari however, A, lumbricoides were least prevalent in hospitals and houses. Simpson Diversity index value of parasitic contaminants isolated from B. germanica collected from houses was 0.92133 and 0.91827 for hospitals. The Shannon-Weiner diversity index calculated value was found highest for P. americana at both sites houses and hospitals as 2.554291 and 2.536765 respectively, which predicted that the rate of parasitic contaminants of both species was not even. Both experimental sites were not significantly different in carriage of parasitic contaminants on cockroaches (F (1,6) =1.795, P= 0.229). Resistance to amoxicillin was found 100% for both gram negative and gram positive isolates followed by cephradine and tetracycline respectively. E. coli was observed as resistant to 3 out of 5 antibiotics (AML, CE, TE) followed by P. aeruginosa that showed resistance to amoxicillin and tetracycline. Germ Kill Vantocil FHC was found more effective bactericide than Germ kill Vantocil in current study. Germ kill Vantocil FHC exhibit highest inhibition zone diameter mean (27+11.575) for 12.5% diluton and 14+13.856 at 50% dilution. Similarly RIZD was 81.81% for 12.5%, dilution respectively. Protein bands of control group were compared with resistant bacterial samples and all protein bands are lying between 236216.2 kDa – 10000 kDa.