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