PATHOGENIC GRAM NEGATIVE COCCI AND RODS

rvsd 4 July 1993, 3 August 1994, 1 Aug 01, 28 Feb 02, 1 Mar 02, 22 July 02, 30 July 03, 28 July 04, 1 Aug07, 15 Aug 07

TFC, 2nd, p 275-299, also Jensen & Wright, Medical Microbiology, TFC’s 7th, pp 304-314, 8th: 304-316, Bauman 2nd: 565-591

Bergey's Manual of Systematic Bacteriology, (1984) four volumes (See p. 756 for overview)

 

Pathogenic Gram negative Beta proteobacteria: can use diffusable nutrients from decomposition, release endotoxin

    Neisseria:                  only Gm- cocci that are pathogenic: fac. anaerobic, diplococci (p 565)

                                        pathogenic have fimbria and capsules, parasitic on mucous mem.

        N. gonorrhoea       STD, susceptible to drying, many are PPNG, (p 567)

                                        diagnosis: gm- diplococci in PMN fr purulent urethral exudate, grow on chocolate agar

                                        50% infected women assymptomatic. Speerm can carry up GU tract, cause PID

          N. meningitidis      (p 568) PoE: nasopharynx, to meningococcemia to meningitis. Up to 40% pop. are carriers, crowding favors

 

Gamma Proteobacteria: Gm-, chemoheterotrophic. Contain most of the Gm- pathogens, especially nosocomial

Enterobacteriaceae          active fermenters, TSI, IMViC differentiates (indole, methyl red, Voges-Proskauer = pink rxn in alkali, citrate). (See p.570 for differentiating scheme)

                                        All release endotoxins, (Remember lipid A and O lipopolysaccharide)

                                        many produce bacteriocins which can lyse other bact with

    Escherichia coli             (p 573) opportunistic, enteropathogenic most common cause GIitis, 1° cause UTI, (plasmid carried.) Jack-in-the-Box problem, beef contamination by strain O157:H7, bloody diarrhea.

    Klebsiella pneumoniae  (P 574) pediatric septicaemia, pneumonia is prominent in alcoholics, UTIs, wound infections

    Serratia marcescens      (p 574) red pigment in some, opportunistic, nosocomial in debilitated: GU, resp., heart valves, meningitis, formerly used as test of germ warfare (1949 & 1968).

    Proteus (vulgaris)         highly motile, norm in fecal flora, incr with antibiotics, cause GU, burn & wound infections, common nosocomial UTI (44% of catheterized Pts have P. mirabilis in urine). swarms on agar medium, can trigger kidney stones, causes infant diarrhea, resistant to many antibiotics, funky smell (p 575)

    Salmonella                     lac-, common in poultry, turtles, antibiotic-treated cattle, differentiate by Kauffmann-White serological tests of O (LPS) and H (flagellar) antigens

        S. typhi                     (storm) fecal/oral, contaminated food, drink, esp drinking water, enters thru GI to lymph vessels, shed in stool, causes typhoid fever with septicemia. (See p 576)

         S. typhimurium          (storm mouse) gastroenteritis ("food poisoning"), 1-3 days after ingstn of contam food (poultry, now some beef) no septicemia. 33% of eggs carry?

    Shigella dysenteriae      inhabits, inflms colon, bloody diarrhea, 2nd most com. travelers = bacillary dysentery (p 578)

 

    Yersinia pestis               bubonic plague, rapid invsn, overwhelming sepsis. endemic: SW ground squirrels (p 579)

    Enterobacter                  com. in soil, GU, nosocomial

 

Pasteurellaceae: very sm. bacilli & coccobacilli, fastidious, non-motile, most parasites, attack mucous memb.

    Hemophilus influenzae:    (P 581) com inhab of upr rsp muc memb. children: otitis media, meningitis (6 mo to 2 yr), etc. (req. blood for growth, need heme and NAD+ ), 2° infctn p colds, can cause pinkeye.

    Bordetella pertussis:        (P 583 & 585) (throughout cough) transmission: resp route, grows on surf trachea & bronchi, inhibit cilia. Causes whooping cough (10 week course!) vaccine = killed cells in DPT shots

 

GAMMA PROTEOBACTERIA: Largest group of proteobacteria, great variety of physiological types

   Pseudomonas aeruginosa   (false, simple organism) psychrophilic, monotrichous, makes pigments (pyocyanin and fluorescein, p 586), infects burns, wounds, resists many antibiotics. Transmitted in H2O, nosocomial. Other species denitrify soil via anaerobic respiration, reduce NO3- releasing N2 to the air

   Francisella tularensis:      zoonosis, trnsmted by flea, tick fr rodents, rabbit fever, tularemia, fever, myalgia

   Legionella spp.                   (P 589) inhabits warm-water supplies, causes Legionairre's Disease: debilitated persons