Cockroaches are among the most common pests in public dwellings and health facilities. Their presence can raise safety concerns, especially as they maybe carriers of pathogenic organisms. This study was carried out to isolate and identify the bacterial flora from German cockroaches (Blattella germanica). Cockroaches collected by hand catches from two public hospital environments in Tebessa city (northeast Algeria) were screened for microbial load from their external surfaces and alimentary tract using standard bacterial protocols. A total of 174 bacterial isolates were isolated from 39 German cockroach specimens. The most common and abundant bacterial species belonged to the Pseudomonas group (23.5%) and Serratia (13.2%). Pathogens like Staphylococcus aureus were also isolated, as well as opportunistic pathogens like Klebsiella species and food spoilage bacteria such as Enterobacter and Citrobacter species were isolated from both external surface and digestive tract of the insect. Generalized linear models (GLM) were performed to analyze the variation of abundances and occurrences of bacterial isolates harboured by B. germanica. The GLMs revealed that the main factors affecting variation of bacterial diversity and abundance were sex and hospital (P < 0.001). The findings of this study suggest that German cockroach acts as reservoir and potential vector of some bacterial pathogens.

Actinomycetes from unexplored habitats are considered as a promising source for novel bioactive compounds with a broad range of biological activities. A study was carried out to isolate and identify rare actinomycetes producing antimicrobial from a natural wetland. Water samples from Fetzara Lake (North eastern-Algeria) were collected and subjected to rare actinomycetes isolation using different rich media. Eight selected actinomycetes were screened in vitro for hydrolytic enzymes, antibacterial and anticandidal activities. Based on the 16S rRNA sequencing, the eight actinomycetes isolates were categorized into four different rare genera Actinomadura, Nocardia, Nonomuraea and Micromonospora. Interestingly, significant anticandidal and antibacterial activities against both Gram-positive and Gram-negative bacteria were observed. Furthermore, the actinomycetes isolates were able to produce different hydrolytic enzymes with potential industrial and food processing applications such as amylase, cellulase, protease and lipase. Overall, the study revealed that the selected aquatic rare actinomycetes recovered from Fetzara Lake presented good candidates to be explored as new sources of bioactive compounds.

The current study highlights some knowledge on the diversity and structure of insect communities and trophic groups living in Sabkha Djendli (semi-arid area of Northeastern Algeria). The entomofauna was monthly sampled from March to November 2006 using pitfall traps at eight sites located at the vicinity of the Sabkha. Structural and diversity parameters (species richness, Shannon index, evenness) were measured for both insect orders and trophic guilds. The canonical correspondence analysis (CCA) was applied to determine how vegetation parameters (species richness and cover) influence spatial and seasonal fluctuations of insect assemblages. The catches totalled 434 insect individuals classified into 75 species, 62 genera, 31 families and 7 orders, of which Coleoptera and Hymenoptera were the most abundant and constant over seasons and study stations. Spring and autumn presented the highest values of diversity parameters. Individual-based Chao-1 species richness estimator indicated 126 species for the total individuals captured in the Sabkha. Based on catch abundances, the structure of functional trophic groups was predators (37.3%), saprophages (26.7%), phytophages (20.5%), polyphages (10.8%), coprophages (4.6%); whereas in terms of numbers of species, they can be classified as phytophages (40%), predators (25.3%), polyphages (13.3%), saprophages (12%), coprophages (9.3%). The CCA demonstrated that phytophages and saprophages as well as Coleoptera and Orthoptera were positively correlated with the two parameters of vegetation, especially in spring and summer. While the abundance of coprophages was positively correlated with species richness of plants, polyphage density was positively associated with vegetation cover. The insect community showed high taxonomic and functional diversity that is closely related to diversity and vegetation cover in different stations of the wetland and seasons.