A total of 100 poultry farms in northern and middle areas of Jordan were sampled to investigate the bacteria associated with airsacculitis in broiler chickens. Of 170 bacterial isolates, 88.2% were identified as Escherichia coli, 8.8% as Ornithobacterium rhinotracheale, and 3% as Bordetella avium. Fourteen serotypes of E. coli were identified among 66 typeable isolates and the remainder were untypeable. The most prevalent serotypes were O1, O8, and O78. The main serotype of O. rhinotracheale was serotype A. Experimental inoculation of O. rhinotracheale via intravenous, intratracheal, and intra-air sac routes resulted in growth retardation, thickening in the air sacs, arthritis, and liver necrosis. Reisolation of O. rhinotracheale from the air sacs, liver, trachea, heart, and spleen at day 7 postinoculation confirmed its role. In vitro susceptibility testing revealed that E. coli isolates were sensitive to gentamicin and colistin, O. rhinotracheale to tetracyline, and B. avium to most of the nine antibiotics examined.

Listeria monocytogenes is a food borne pathogen which usually infects individuals with impaired cellular immunity and the healthy. Gastrointestinal tract (GIT) of the humans has lots of defensive mechanisms placed to prevent pathogens from establishing themselves and cause infectious diseases. Survival depends on the pathogen’s ability to overcome such preventive mechanism of the host. Listeria monocytogenes exhibits array of mechanisms that ensure its survival against these stressor. These stressors include gastric acid, bile salt, low oxygen tension, antimicrobial peptides e.t.c. Acid tolerance system (ATR), glutamate decarboxylase system (GAD), BilE system, MVs, oxygen sensors are used by Listeria monocytogenes to enhance its chances of survival within host. Our interest here is to look at such adaptive mesures with respect to the stressors encountered.

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