Contaminated feed-borne Bacillus cereus aggravates respiratory distress post avian influenza virus H9N2 infection by inducing pneumonia

Abstract

Avian influenza virus subtype H9N2 is identified in chickens with respiratory disease while Bacillus cereus ( B. cereus ) has been frequently isolated from chicken feed in China. However, the roles of co-infection with these two pathogens remain unclear. In the present study, SPF chicks were intragastrically administered with 10 8 CFU/mL of B. cereus for 7 days and then inoculated intranasally with 100 EID 50 of H9N2 three days later. Alternatively, chickens were initially inoculated with H9N2 and then with B. cereus for one week. Post administration, typical respiratory distress persisted for 5 days in both co-infection groups. Gizzard erosions developed in the groups B. cereus /H9N2 and B. cereus group on 7 th day while in group H9N2/ B. cereus on 14 th day. More importantly, both air-sac lesions and lung damage increased significantly in the co-infection group. Significant inflammatory changes were observed in the B. cereus group from day 7 to day 21. Moreover, higher loads of H9N2 virus were found in the co-infected groups than in the H9N2 group. Newcastle Disease Virus (NDV) specific antibodies were decreased significantly in the H9N2/ B. cereus group compared to the B. cereus and the B. cereus /H9N2 groups. Nonspecific IgA titers were reduced significantly in the B. cereus group and the H9N2/ B. cereus group compared to the control group. In addition to this, lower lymphocyte proliferation was found in the con-infection groups and the H9N2 group. Hence, feed-borne B. cereus contamination potentially exacerbates gizzard ulceration and aggravates H9N2-induced respiratory distress by inhibiting antibody-mediated immunity and pathogen clearance. Thus controlling the B. cereus contamination in poultry feed is immediately needed.

Gastric Ulceration and Immune Suppression in Weaned Piglets Associated with Feed-Borne Bacillus cereus and Aspergillus fumigatus

“…[24]. In our previous study, feed-borne B. cereus co-infection with avian influenza virus (H9N2) has produced significant gizzard erosions and ulceration(GEU) in all bird groups by damaging to the epithelium of the digestive tract, which facilitates other susceptible pathogens [19]. More recently, chickens exposed to the B. cereus co-infection with Chlamydia psittaci developed a severe GEU syndrome suggesting that injury to the koilin layer of the gizzard with B. cereus toxins could directly affect the gizzard membrane, while the intraesophageal C. psittaci infection also promotes the development of the GEU [26].…”

“…Afterwards, positive tubes were streaked onto Mannitol Yolk Polymyxine Agar (MYP) (Oxoid, Beijing, China), and then colonies were grown for 18-24 h at 30 • C. Typical colonies grown on MYP were confirmed with a biochemical test as described previously [31]. Furthermore, isolates of Bacillus spp were identified by molecular analysis using the 16s rRNA gene, nheA gene, nheB gene, nheC gene, Em1gene and CytK gene as previously described [19]. The MPN of B. cereus was detected based on the number of tubes at each dilution in which the presence of B. cereus was noted [32].…”

Mimicking the passage of avian influenza viruses through the gastrointestinal tract of chickens

“…However, gizzard pathology has been observed in infections mainly with bacteria and fungi, but also with (non-enveloped and thus more resistant) adenoviruses (Gjevre et al, 2013). As for influenza infections, a recent report describes that a co-infection with H9N2 virus potentially exacerbates gizzard ulceration induced by feed-borne Bacilus cereus contamination, but the virus alone does not cause gizzard damage (Zhang et al, 2019). Thus, it seems unlikely that Influenza viruses infect cells of the gizzard on a regular basis.…”

Extent of microbiological contamination among swabs drawn from selected wards and kitchens at AL -Yarmouk Teaching Hospital in Baghdad –Iraq

“…During this year, the most identified organism in our wards was Gram-positive Bacillus 26.8% (n=197). Bacillus is very pathogenic and could develop fatal infections, mainly in neonatal and immunocompromised patients , Zhang et al(2019). Moreover, Bacillus cereuscould cause gastrointestinal bleeding, necrosis and fatty changes in liver, Dhafer (2018).…”