BIOL 2421 Microbiology         Bacterial Diseases         Gram Negative [General]   Dr. Weis

Gamma Proteobacateria

          Largest subgroup of Gram negative bacteria, Families consist of:

          Pseudomonales, Legionellales, Vibrionales, Enterobacteriales,  Pasteuralles

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ENTEROBACTERIACEAE

            Comprised by Salmonella, Shigella, Escherichia, Klebsiella, Enterobacter, Serratia, Proteus, Morganella, Providencia, Yersinia, and others that affect plants.

            Gram negative rods

            Facultative anaerobes

            Oxidase (-)

            Catalase positive

            Ferment glucose

            Reduce nitrates to nitrites

            Virulence: Fimbria for attachment

                              Sex Pili for tranmsision of resistance (AB)

                              Bacteriocins à proteins that cause the lysis of related species

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Enterobacter

     E. aerogenes

     E. cloacae

            Nosocomial infection

            Reservoir: colon, soil, water, sewage

            Diseases: UTI, pneumonia

            Virulence factor: AB resistance

                                        Endotoxin

            TX: AB [broad spectrum penicillin]

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Klebsiella

            Klebsiella  pneumonia

                        Facultative anaerobe

                        Nonmotile

                        Nosocomial infections

                        Rare, but severe pulmonary infection

                        Reservoir: Human URT, soil, water

                        Clinical signs: dark brown to cherry red jelly like sputum

                                                Lung abscesses

                                                Empyema

                        Most common in diabetics, alcoholics, chronic respiratory disease

                        Virulence factor: polysaccharide capsule

                        TX: AB [cephalosporins and aminoglycocides]

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Serratia

     Serratia marcescens

            Nosocomial : catheters, Saline irrigation solutions          

            Reservoir: colon, soil, water

            Diseases: UTI, pneumonia

            Virulence factor: AB resistance

                                        Endotoxin

            TX: AB [broad spectrum penicillin]

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Proteeae (part of the Enterobacteriaeceae group)

            Comprised of Proteus, Morganella, Providencia

     Proteus

            P. mirabilis

            P. vulgaris

                        Highly motile. Peritrichous flagella

                        Habitat: colon, soil, water

                        Disease: UTI, wound sepsis (catheter infections)

                        Virulence: Endotoxin

                                          Urease +

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     Morganella

            M. morganii

                        Habitat: feces, soil, water

                        Clinical disease: found in superficial wounds where normal flora is absent

                                                   Infections of ear, sinuses, urinary tract

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     Providencia

            P. rettgeri

            P. alcalifaciens

            P. stuartii

                        Habitat: feces, soil, water

                        Clinical disease: found in superficial wounds where normal flora is absent

                                                   Infections of ear, sinuses, urinary tract

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Pasteurellales

            Nonmotile, gram neg rods

                        Haemophilus [see other notes]

                        Pasteurella

                                    Pasteurella multocida

                                                Pneumonia and sepsis in animals

                                                Zoonotic Dz: transmitted by animal bite [dog, cat]

                                                            Humans: abscess à arthritis

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Epsilon proteobacteria

            Slender gram neg rods

            Helical or vibroid

            Motile

            Microaerophilic

      Campylobacter

            Transmission: Indirectà contaminated or undercooked food; contaminated water

            C. jejuni

                        Clinical signs: Enteritis, ulcerative colitisàwatery, bloody diarrhea

                                    Can progress to endocarditis à septic arthritisà meningitis

                        DX: growth on selective media

                        TX: AB [erythromycin, ciprofloxacin]

            C. fetus

                        Diseases: bacteremia in susceptible patients [DM, cirrhosis]

                                        Diarrhea

            C. coli

                        Diseases: diarrhea

     Helicobacter pylori

            Diseases: peptic ulcers

                           Gastric carcinoma

            Virulence factor: Urease +

            TX: AB [metronidizole]

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OTHER ORGANISMS

Bacteroidetes

     Bacteroides fragilis

            Gram neg rod

            Anaerobic

            nonmotile

            Reservoir: Human intestine

            Diseases: PID, Peritonitis, Abscesses

            TX: Metronidizole

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Francisella tularensis

            Gram negative pleomorphic coccobacillus

            Non motile

            Non sporeformer

            Reservoir: Rabbits and Rodents that carry Type A

                              Water and aquatic mammals that carry Type B

            Transmission: Ingestion, inoculation, inhalation, contamination, biting vector

            Incubation: 5-8 days

            Clinical sign: Headache/chills/ fever à N/Vàpustular papule that ulcerates

                        Focal necrosis of infected organs:

                                                Finger, eye, Lymphatic system, liver, kidney, lung

            Virulence factors: capsule

                                      Endotoxin (LPS)

            TX: AB [streptomycin]

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Streptobacillus

            S. moniliformis

                        Causative agent of Streptobacillary rat bite fever

                        Reservoir: oropharynx of rats

                        Transmission: Direct (bite), Indirect (contamination of milk)

                        Clinical Signs: Flu like signsà rashà polyarthralgiaà endocarditis

                        DX: Id organism on culture of blood or joint fluid

                        TX: AB [penicillin or erythromycin]

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Plesiomonas shigelloides

            Gram neg rod

            Facultative anaerobe

            Reservoir: Gut of fish

            Transmission: Eating raw fish, contaminated food or water

            Clinical Disease: Diarrhea

            TX: AB

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Aeromonas hydrophilia

            Gram neg rod

            Reservoir: soil and water

            Transmission: contaminated food

            Clinical Disease: diarrhea

            Virulence factor: enterotoxin

            TX: AB

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Alcaligenaceae

            Alcaligenes denitrificans

            Alcaligenes faecalis: found in the soil and water, not a pathogen

            Bordetella pertusis

                        Gram neg bacillus

                        Aerobic

                        Nonmotile

                        Transmission: Respiratory droplet

                        Clinical Disease: Pertussis [Whooping cough]

                                    Malaise/ fever à mucus accumulatesà paroxysmal coughing

                        Virulence factor: Pili/Fimbria that attach to cili of URT cells

                        DX: organism on culture sample

                        TX: AB [penicillin, erythromycin]

                        Prevention: Vaccination [DTaP]  p = pertussis