About Morganella species

a powerpoint slide on Morganella

1. Morganella
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2. Classification
Phylum: Proteobacteria
Class: Gammaproteobacteria
Order: Enterobacteriales
Family: Enterobacteriaceae
Genus: Morganella
Species: morganii
Sub species: morganii(trehalosenon-fermenter)
Biogroups: A,B,C,D
Sub species: sibonii(trehalosefermenter)
Biogroups: E,F,G
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3. Subspeciesfurtherdividedintobiogroups
Fourbiogroups(A,B,C,andD)ofM.morganii
subspeciesmorganii
Basedlargelyontheabilityofstrainstoformlysineor
ornithinedecarboxylaseorbothorneither.
BiogroupAisODC+/LDC-,BiogroupBODC+/LDC+,
BiogroupCisODC-/LDC-,BiogroupDisODC-/LDC+,
Threebiogroups(E,F,andG)ofM.morganii
subspeciessibonii
Basedontheabilityofstrainstoproducelysineor
ornithinedecarboxylaseorboth,andindoleandgrowin
thepresenceofKCN
BiogroupEisODC+/LDC+,BiogroupFisODC-/LDC
variable,andBiogroupGisODC+/LDC-
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4. Genus name: named after the British bacteriologist H. de R.
Morgan, who first studied this organism.
G + C content of the DNA is 50 mol%.
HABITAT
Intestinal and feces pathogen of man, other mammals, and
reptiles.
MACROSCOPIC APPEARANCE
Some Morganellastrains appear hemolytic when cultured
on Blood Agar, while others produce a reddish-brown
pigmentation.
METABOLIC PROPERTIES
Facultativelyanaerobic. Chemoorganotrophic, having both
fermentative and respiratory type metabolism. Acid
production from mannose, but gas is not produced.
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5. MICROSCOPIC APPEARANCE
Gram Stain: Gram-negative.
Morphology: Straight rods.
Size: 0.6-0.7 micrometers by 1.0-1.7 µm.
Motility: Motile by peritrichousflagella (less than 30
˚c) and nonmotile(above 30°C), swarming does not
occur.
Capsules: None.
Spores: None.
Other: Originally classified in the genus Proteus as
Proteus morganii.
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6. KEY BIOCHEMICAL REACTIONS
Oxidase-negative.
Catalase-positive.
Urease-positive.
Indole-positive.
Voges-Proskauer-positive.
Simmons-Citrate-negative.
Methyl-Red-positive.
H
2 S-negative.
Phenylalanine deaminase:positive.
Ornithine-decarboxylase-positive.
Produces acid from mannose.
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7. RECOMMENDED MEDIA
For culture: TrypticSoy Agar (TSA), Blood Agar 5%.
For selective isolation: MacConkeyAgar, EMB Agar,
SeleniteBroth, TetrathionateBroth.
For maintenance: TrypticSoy Agar for short-term
maintenance and lyophilizationfor long-term
preservation.
INCUBATION
Temperature: 35 degrees C. Time: 18-24 hours.
Atmosphere: Aerobic.
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8. Fermentation of carbohydrates
•Acidifyglucose,usuallywithgasformation,
andmannose
•Donotacidifylactose,sucrose,salicin,
mannitol,xylose,adonitol,orinositol.
•Becauseofaninabilitytoacidifysucroseand
lactose,M.morganiistrainsformcolorless
coloniesonMacConkey,eosin-methylene
blue,xylose-lysine-deoxycholate,and
Salmonella-Shigellaagars.
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9. Introduction
Morganellamorganii
Are small, Gram-negative, motile
bacilli, but unlike Proteus species
do not produce swarming on solid
media.
Oxidase negative; catalase, indole,
citrate and urease positive.
They are facultativelyanaerobic
and non-encapsulatedfound in
the feces and intestines of
humans, dogs, and other
mammals.
Growon blood agar or on Mac-
Conkeyagar.
Fermentsglucose and mannose
but not lactose.
Decarboxylateornithine,
hydrolyze urease, and reduce
nitrates.
Do not liquefy gelatin and do
not produce hydrogen sulfide.
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10. It is known to be a causative organism of opportunistic
infectionsin the respiratory tract, the urinary tract, and in
wound infections.
It can cause devastating infections in the neonates and
postoperative stages, especially in diabetic patients .
The risk of infection is particularyhigh when a patient
becomes neutropenic(neutrophils) as a result of
myelosuppressive(bonemarrowsuppresion) chemotherapy
.
Massive hemolysiscan be associated with bacterial
infection and has been reported mainly in cases of
Clostridialor Vibriosepsis .
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11. History
The first isolation of this bacteria was done by a man named Castellani
in 1905, and he named it Bacterium columbensea.
In 1906 when Morgan came across this bacteria while studying
summer infantailediarrhea.
he was unaware that it was indeed the same bacteria that was found by
Castellani. Morgan described this as a non-lactose fermenting bacteria
-different from the other Bacillus type bacteria. He named this
Morgan's Bacillus .
It was later named, in 1919, Bacillus morganiiby Winslow.
Years later, Raussperformed further evaluation of the bacteria and
realized it was very similar to the Proteusgroup and although there
were marked differences, he renamed the bacteria Proteus morganii.
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12. History....contd
Finally in 1943, Fulton made the connection that the
bacteria Proteus morganiiwas in fact the same bacteria
discovered by Castellaniin 1905 and he proposed a new
genus name of Morganella. The species would be called M.
morganiiand Castellani'sspecies would be called M.
columbensis. M. morganiiwas unable to ferment lactose or
sucrose but was able to produce indole.
In 1962, Ewing found the M. columbensiswas actually E.
coli,which left M. morganiias the only species in the
genus. This led Ewing to disregard the genus and relate
moganiito the Proteus genus.
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13. Finally in 1976, morganiiwas put in its rightful place in the
genus of Morganella.
The differentiation between the two genera was finally
made by Brenner using DNA-DNA hybridization, which
showed less than 20% homology between P. morganiiand
Proteus. The differences were further backed by the ability
for trehalosefermentation (O'Hara et al., 2000).
Morganellais also distinguishable from the genus Proteus
by the lysine iron agar test and by the ability of the genus
Proteusto differentiate in to swarmercells when
colonizing a new habitat (Manos & Belas, 2006).
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14. Clinical manifestations
GI diarrhoea
Sepsis(presence of pus forming bacteria or their toxins in blood or
tissues)
Pneumonia
Wound infections
Pericarditis(inflammation of pericardium)
Chorioaminonitis(inflammation of the fetal membranes (amnion
and chorion)
Endophthalmitis(purulent inflammation of the intraocular
fluids)
Empyema(collection of pus in body cavity)
Spontaneous bacterial peritonitis (inflamationof peritoneum)
CNS infections
Ear and sinus infections
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15. Genome structure
.M. morganiihas a complete genome sequence
(3,826,919-bp) with a G+C content of 51.15%
3,565 protein-coding sequences
Genes encoding for drug resistance are ;
ampC-ampR, MBL, Telluriteresistance operon, and
Tetracycline resistance
blaCTX-M, blaSHV, blaTEM, blaOXA
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16. VIRULENCE FACTORS
Adhesins
Hemolysin
Calcium-dependent
The hemolysinis serologically and functionally identical to E.
coli hemolysinHlyAand is associated with high virulence of
strains for mice and chick embryos
Urease
Constitutively produced
Active at acidic pH, promote colonization of intestinal
epithelium protecting against the acidity of stomach
Other enzymes
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17. PATHOGENICITY
There is considerable evidence that Morganella
species play a pathogenic role in urinary tract
infections, particularly for those of nosocomial
origin. It is an opportunistic secondary invaders
rather than a primary pathogen at other sites and
has been isolated from bacteremias, respiratory
tract, and wound infections.
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18. Type IV pili: adheres to hosts
The ability ofMorganellato cause infections in the urinary tract may be
due to the MR/K hemagglutininthat enhances adherence to urinary
catheters . Additionally,Morganellaproduces a urease that predisposes
to encrustation of urinary catheters .
TheMorganellaureasealso can be activated at a low pH, which may
enhance the bacterial survival at low pH.This can have many adverse
effects including the formation of stones causing renal damage, and it
can also lead to a urinary tract infection (Manos & Belas, 2006).
Morganellaspecies may also produce a hemolysin, which enhances
virulence by lysing erythrocytes due to the formation of hydrophilic
pores in the cell wall .
Due to its highly mobile state, Morganellais able to rapidly colonize
the gut. Coupled with enlargement of the Peyer’spatches in the gut
and specific IgAresponses, it is able to change the environment of the
host very quickly.
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19. Risk factors for M. morganii
infection include the following
Prior exposure to ampicillinand other beta-lactam
antibiotics
Diabetes mellitus
Advanced age
Surgical procedures
Perinatalexposure
Abscesses or soft tissue infections following snakebite
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20. Antibiotic tests
Susceptible to Resistant to
Cefepime
Imipenem
Meropenem
Piperacillin
Aminoglycosides
Ceftazidime
Other 3
rd
generation
cephalosporins
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21. Laboratory diagnosis
Specimens:faeces,urine, wound and ear discharges
Diagnosis: culture
Identification of M. morganiiis made by recovery of small,
non-fermenting colonies, oxidase-negative, catalase and
indole-positive gram-negative rods on blood agar or
MacConkey agar.
M. morganiiferments glucose and mannose but not
lactose.
M morganiiis motile(at temprbelow 30°C), facultatively
anaerobic, and nonencapsulated, and it hydrolyzes urease
and reduces nitrates.
Unlike Proteusspecies, swarming does not occur.
M. morganiiurinary tract infections are often associated
with an alkaline urine pH.
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22. Culture on phenylalanine deaminaseagar medium : + Production of
green colour(Phenylpyruvicacid thus formed reacts with ferric
chloride producing a green colored compound thus turning the
medium dark green).
Mac-Conkeyagar: flat, colorless 2 to 3 mm non-lactose fermenting
colonies.
Sheep-blood agar: flat, colorless 2 to 3 mm colonies, no swarming,
Some strains appear hemolytic, while others produce a reddish-brown
pigmentation.
Eosin-methyleneBlue Agar (EMB): colorless or light purple colonies.
Triple Sugar Iron Agar (TSI): Yellow butt, red slant (K/A) = ferments
glucose only, no H
2S,no gas
Catalase: +
Oxidase: -
IMViC: +++-
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23. ANTIMICROBIAL THERAPY
The antibiotic of choice depends upon the site of infection, the
nature of the host and the local pattern and prevalence of
resistance.
Bacteremia: A third-generation cephalosporin , aminoglycoside
+cephalosporin::a course of at least 2 weeks appears reasonable.
Urinary Tract Infection:oralquinolones likeciprofloxacin,
third generation cephalosporins andtrimethoprim-
sulfamethoxazole.
Wound Infection:abroad-spectrum agent such aspiperacillin-
tazobactam, third generation cephalosporinslikeceftriaxone,
cefipimeor a quinolonewith an antianaerobicdrug.
For infections caused by an ESBL-producing strain, the drug of
choice is generally a carbapenem.
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24. Intra-abdominalInfection: Broad-spectrum antibiotic such
aspiperacillin-tazobactamare the first choice;other options include
the use of third generation cephalosporins likeceftriaxone, cefipimeor
afluoroquinolone.
Neonatal Infections: a third generation cephalosporin such
ascefotaximeand an aminoglycoside.
UnderlyingDiseases: treatment of other diseases
Thethird-generation cephalosporins ceftriaxone, cefotaxime, and
ceftazidime are more active againstMorganella, with MIC90s ranging
from 0.03 to 32mg/mL .The MICs for cefotaxime and ceftazidime are
0.015 and 0.06mg/mL for inducible strains but 4 and 8mg/mL for
constitutive hyperproducers, respectively.
Trimethoprim-sulfamethoxazoleis also active against
someMorganella(MIC50s-0.06mg/mL; MIC90s 16mg/mL)
Thefluroquinolonesare highly active againstMorganella, with the
MIC90s for most isolates below 0.25 mg/mL
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25. VACCINES
There are no vaccines in development
againstMorganella.
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26. PREVENTION OR INFECTION
CONTROL MEASURES
•Checking of rectal conlonizersof this
organism, vigorous handwahing
practices, use of contact isolation for
infected or colonized patients could
prevent the spread of antimicrobial
resistance and ESBL producers.
•Hospital policy regarding antibiotic use
may play important role in scenarios
when multiple clones of ESBL producers
are present in hospital.
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27. References
Chen et al ,2012, Whole-genome sequencing and identification
of MorganellamorganiiKT pathogenicity-related genes,BMC
genomics, licensee BioMedCentral Ltd.
Monas j and belasR (2006), prokaryotes
,www.yumphu.com/articles ,(6),245-269.
ParijaSC,(2012) textbook of microbiology and immunology,2
nd
edition, A division of Reed Elsevier India private ltd., India .
O’Hara, C. M., Brenner, F. W. & Miller, J. M.
(2000).Classification,identification, and clinical significance of
Proteus,Providencia, and Morganella.ClinMicrobiolRev 13,534–
546.
Patil AB, Nadagir SD, Lakshminarayana SA,and Syeda FM.
(2012),Morganellamorganii, subspecies morganii, biogroupA:
An unusual causative pathogen of brain abscess, J NeurosciRural
Pract. 3(3): 370–372.
https://microbewiki.kenyon.edu/index.php/Morganella_margan
aii
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