Bacterial Pathogenesis/Infections PDF

Terminology related to Bacterial Pathogenesis/Infections  Important Terms Infection: The colonisation and/or invasion and multiplication of pathogenic microrganisms in the host with or without the manifestation of disease Disease: An abnormal condition of body function(s)...

Terminology related to Bacterial Pathogenesis/Infections  Important Terms Infection: The colonisation and/or invasion and multiplication of pathogenic microrganisms in the host with or without the manifestation of disease Disease: An abnormal condition of body function(s) or structure that is harmful to the affected individual (host) – may be caused by a pathogen Vector: an animal that transfers an infectious agent from one host to another, usually an insect (Arthropod) Carrier: (Carrier State): A symptomless individual who is host to a pathogenic microorganism with the potential to pass the pathogen to others  Important Terms PATHOGENS: Microbes capable of causing disease in the host. A HOST is any organism (Human) that another organism (Bacteria) lives in or on. The PARASITE is the organism living inside (endoparasite) or on (ectoparasite) the HOST. This means the parasite benefits at the expense of the host. The host-parasite relationship is typically species specific. SAPROPHYTES: Free living microbes subsisting on dead or decaying organic matter.  Important Terms SYMBIOSIS: neutral, antagonistic or synergistic relationship between two dissimilar organisms (SYMBIOTES, SYMBIONTS) living in close association with each other. COMMENSALISM : relationship between two species in which one is benefited, and the other is not affected, neither negatively nor positively. PARASITISM (+/-): relationship between two species in which one benefits (parasite) from the other (host); usually involves negative effects on the host. MUTUALISM: mutually beneficial relationship between two species.  Important Terms Microbial Pathogenesis: Process of causing disease/ the ability a species of bacteria to produce disease Colonization: Presence of microbes at a site of body Does not imply tissue damage or disease symptoms Does not imply multiplication of the microbe Virulence: The measure/degree of pathogenicity of a strain belonging to a pathogenic species. Commonly ascertained by measuring the dosage (no of organism) required to cause disease  Important Terms Primary/True Pathogen: Any microorganism capable of causing disease; an infecting agent Opportunistic pathogens: (Potentially Pathogenic) bacteria Do not cause disease under normal conditions but can cause disease in immunocompromised patients, or when they find their way to another site other than their normal habitat. Nosocomial pathogen: a pathogen that causes an infection acquired in a hospital setting that was not present in the host prior to admissionànosocomial infection  Important Terms Primary Infection - Initial infection with a parasite in a host Reinfection - Subsequent infections with same parasite in the host Secondary Infection - New parasite setting up infection in a host when resistance is lowered Focal Infection (Focal Sepsis) - Localised infections à may lead to sepsis Generalized Infection - Systemic infections Cross Infection - A new infection in a patient set up from another host  Important Terms Nosocomial/Hospital acquired infection - Cross infection acquired in hospitals Endogenous Infection - From within the body Exogenous Infection - From outside the body Inapparent Infection (Subclinical Infection) - Clinical effects are not apparent Atypical Infection - Characteristic clinical manifestations are not present Latent Infection - Hidden infection  Important Terms Epidemic: Disease occuring in an area in numbers exceeding the normal expectancy Endemic: The infection is constantly present at a low level in a specific population Pandemic: A widespread epidemic occuring widely throughout a country, continent, or globally