Here is a list of some bacteria which causes diseases in man. Also learn about its prevention and control.
1. Salmonella Typhosa:
Rods, 0.6 to 0.7 by 2 μ, occurring singly, in pairs, and occasionally in short chains. Motile by means of peritrichous flagella; sometimes non-motile. Gram-negative.
Disease Produced – The cause of typhoid fever in man. An acute infectious disease characterized by continued fever, involvement of lymphoid tissues, enlargement of spleen, rose spots on the trunk, irritation of walls of gastrointestinal tract with formation of ulcers and production of diarrhea. During first two weeks organism may be recovered from blood; from urine and feces after second week. Widal reaction becomes positive during second week. Disease may be transferred to laboratory animals by inoculation.
Carriers – Typhoid fever may be transferred from person to person by individuals known as carriers. A carrier is one who has recovered from the disease but still continues to discharge the bacilli in the intestinal contents. These organisms are no longer pathogenic to the carrier but are capable of producing typhoid fever when they reach the intestinal tracts of other persons.
Carriers generally harbor the organisms in their gall bladder, which is believed to be the reservoir of the bacilli. Removal of the gall bladder appears to be the best method for the treatment of some carriers.
Diagnosis – Antigenic structure – 9, 12, (Vi), d. Motile species contain two antigenic components – (i) flagellar or H antigen and (ii) somatic or O antigen.
Agglutinins may be produced against both components. During infection, both kinds of agglutinins present in blood serum. Typhoid fever may be diagnosed by testing for presence of agglutinins in blood stream.
Widal Reaction – A specific agglutination test for diagnosis of typhoid fever. Test performed by mixing gradually increasing dilutions of patient’s serum with a suspension of typhoid bacilli and observing for presence of agglutination the organisms. Since reaction of patient’s serum does not become positive until during second week of infection, test of no value in early days of disease.
During first few days of disease, it is better to make a diagnosis by isolating the organism from feces, preparing a suspension, and testing for agglutination against a specific immune serum.
Source of Infection – Feces and urine of infected persons or carriers.
Mode of Transmission – Transmitted through direct contact with patients or carriers. Foods contaminated by fingers of typhoid patients or carriers. The most common source of typhoid outbreaks is through milk contaminated by a dairy worker. Oysters and shellfish, grown in sewage-polluted waters, may harbor the organism. Water-borne epidemics, due to sewage contamination, sometimes occur.
Incubation Period – From 3 to 35 days, usually 7 to 14 days.
Susceptibility and Immunity – Susceptibility to disease is general. Natural immunity exists to some extent in adults. Permanent acquired immunity usually follows recovery from disease. Active artificial immunity of about 2 years’ duration developed by inoculation with typhoid bacterin.
Bacterin prepared by growing a freshly isolated smooth strain on a solid medium, suspending growth in saline, standardizing suspension to contain about 1 billion cells per milliliter, killing organisms at 53°C. for 1 hr., then preserving with 0.25 per cent tricresol.
Three injections of bacterin in doses of 500 million, 1 billion, and 1 billion at intervals of 7 to 10 days are generally sufficient for establishing a satisfactory active immunity.
Prevalence – Widely distributed throughout world. Endemic in some rural areas in United States but occurring now commonly as sporadic cases and small carrier epidemics. Incidence steadily falling owing to protection of water, food, and milk supplies.
Prevention and Control – Protection and purification of water supplies. Sanitary disposal of human sewage. Pasteurization of milk and milk products. Sanitary control of foods and shellfish. Fly control and protection of foods against fly contamination. Periodic examination of individuals who handle foods for public consumption. Immunization of population by use of a bacterin. Education of public on sources of infection and modes of transmission.
Isolation of Infected Individuals – Disinfection of all bowel and urinary discharges and articles contaminated with such discharges. Vaccination of susceptible members in family or household of patient. Administration of chloramphenicol in large oral dose followed by oral doses every 6 hr. until temperature normal, then smaller doses for total of 2 weeks.
2. Salmonella Schottmuelleri:
Rods 0.6 to 0.7 by 2 to 3 μ, occurring singly and in pairs. Usually motile by means of peritrichous flagella. Gram-negative.
Disease Produced – The cause of paratyphoid fever in man. Also responsible for cases of food poisoning. The disease is not naturally found in animals. Infection characterized by continued fever, involvement of the lymphoid tissues of the intestines, enlargement of the spleen, and sometimes rose spots on the trunk; usually accompanied by a diarrheal condition. Organism may be present in feces, urine, and blood and may be identified by fermentation and serological reactions.
Source of Infection – Feces and urine of infected persons or carriers; water or foods contaminated with discharges of infected persons or healthy carriers.
Mode of Transmission – By direct contact with infected persons or by articles soiled with discharges of infected persons; through water, food, and milk contaminated with discharges of infected persons or carriers; and by insects.
Incubation Period – From 1 to 10 days.
Susceptibility and Immunity – Susceptibility is general. Natural immunity believed to exist in some persons. Acquired immunity is usually permanent after recovery from disease. Active artificial immunity of about 2 years duration developed after inoculation with a bacterin.
Prevalence – Occurs sporadically or in limited outbreaks from contact with infected persons or from contaminated water, milk, and other foods.
Prevention and Control – Protection and purification of water supplies. Sanitary disposal of human sewage. Pasteurization of milk and milk products. Sanitary control of foods and shellfish. Fly control and protection of foods against fly contamination. Periodic examination of individuals who handle foods for public consumption. Immunization of population by use of a bacterin. Education of public on sources of infection and modes of transmission.
Isolation of Infected Individuals – Disinfection of all bowel and urinary discharges and articles contaminated with such discharges. Vaccination of susceptible members in family or household of patient. Administration of chloramphenicol in large oral dose every 6 hr. until temperature normal, then smaller oral doses for total of 2 weeks.
3. Salmonella Paratyphi:
Rods, 0.6 by 3 to 4 μ, occurring singly. Usually motile by means of peritrichous flagella. Gram- negative.
Disease Produced – The cause of paratyphoid fever in man. Also responsible for cases of food poisoning. Disease is not naturally found in animals. Infection characterized by continued fever, involvement of the lymphoid tissues of the intestines, enlargement of the spleen, and sometimes rose spots on the trunk; usually accompanied by a diarrheal condition. Organism may be present in feces, urine, and blood and may be identified by fermentation and serological reactions.
Source of Infection – Feces and urine of infected persons or carriers; water or foods contaminated with discharges of infected persons or healthy carriers.
Mode of Transmission – By direct contact with infected persons or by articles soiled with discharges of infected persons; through water, food, and milk contaminated with discharges of infected persons or carriers; and by insects.
Incubation Period – From 1 to 10 days.
Susceptibility and Immunity – Susceptibility is general. Natural immunity believed to exist in some persons. Acquired immunity is usually permanent after recovery from disease. Active artificial immunity of about 2 years’ duration developed after inoculation with a bacterin.
Prevalence – Occurs sporadically or in limited outbreaks from contact with infected persons or from contaminated water, milk, and other foods.
Prevention and Control – Protection and purification of water supplies. Sanitary disposal of human sewage. Pasteurization of milk and milk products. Sanitary control of foods and shellfish. Fly control and protection of foods against fly contamination. Periodic examination of individuals who handle foods for public consumption. Immunization of population by use of a bacterin. Education of public on sources of infection and modes of transmission.
Isolation of Infected Individuals – Disinfection of all bowel and urinary discharges and articles contaminated with such discharges. Vaccination of susceptible members in the family or household of patient. Administration of chloramphenicol in large oral dose every 6 hr. until temperature normal, then smaller oral doses for total of 2 weeks.
4. Salmonella Typhimurium:
Rods, 0.5 by 1 to 1.5 μ, occurring singly. Motile by means of peritrichous flagella. Gram-negative.
Disease Produced – Causes food-poisoning in man. A natural pathogen for all warm-blooded animals.
Source of Infection – Feces and urine of infected persons or carriers; water or foods contaminated with discharges of infected persons or healthy carriers.
Mode of Transmission – By direct contact with infected persons, or by articles soiled with discharges of infected persons or carriers; through water, food, and milk contaminated with discharges of infected persons or carriers; and by flies.
Incubation Period – From 1 to 10 days.
Susceptibility and Immunity – Susceptibility is general. Natural immunity believed to exist in some persons. Acquired immunity usually permanent after recovery from disease. Active artificial immunity of about 2 years duration developed after inoculation with a bacterin.
Prevention and Control – Protection and purification of water supplies. Sanitary disposal of human sewage. Pasteurization of milk and milk products. Sanitary control of foods and shellfish. Fly control and protection of foods against fly contamination. Periodic examination of individuals who handle foods for public consumption. Immunization of population by use of a bacterin. Education of public on sources of infection and modes of transmission.
Isolation of Infected Individuals – Disinfection of all bowel and urinary discharges and articles contaminated with such discharges. Vaccination of susceptible members in the family or household of patient. Chloramphenicol and tetracyclines have limited and irregular effect.
5. Salmonella Enteritidis:
Rods, 0.6 to 0.7 by 2 to 3 μ, occurring singly, in pairs, and occasionally in short chains. Motile by means of peritrichous flagella. Gram-negative.
Disease Produce – A cause of food poisoning in man. Organism produces natural infections in domestic and wild animals. Disease usually characterized by acute diarrhea with abdominal cramps, fever, nausea, and vomiting. Organism may be recovered from feces or from site of localized infection during acute illness.
Source of Infection – Feces and urine of infected persons or carriers; water or foods contaminated with discharges of infected persons or healthy carriers.
Mode of Transmission – By direct contact with infected persons, or by articles soiled with discharges of infected persons; through water, food, and milk contaminated with discharges of infected persons or carriers; and by insects.
Incubation Period – From 1 to 10 days.
Susceptibility and Immunity – Susceptibility is general. Natural immunity believed to exist in some persons. Acquired immunity usually permanent after recovery from disease. Active artificial immunity of about 2 years’ duration developed after inoculation with a bacterin.
Prevalence – Occurs sporadically or in limited outbreaks from contact with infected persons or from contaminated water, milk, and other foods.
Prevention and Control – Protection and purification of water supplies. Sanitary disposal of human sewage. Pasteurization of milk and milk products. Sanitary control of foods and shellfish. Fly control and protection of foods against fly contamination. Periodic examination of individuals who handle foods for public consumption. Immunization of population by use of a bacteria. Education of public on sources of infection and modes of transmission.
Isolation of infected individuals. Disinfection of all bowel and urinary discharges and articles contaminated with such discharges. Vaccination of susceptible members in the family or household of patient. Chloramphenicol and tetracyclines have limited and irregular effect.