Organism Description Drug of choice

1.Staphylococcus aureus Skin and soft tissue infections nafcillin, oxacillin,

Acute endocarditis- tricuspid valve dicloxacillin
Pneumonia mrsa resistant- vancomycin
Osteomyelitis and septic arthritis
Toxic gastroenteritis –mayo salad!
Scalded skin syndrome
Toxic shock syndrome

2. staphylococcus epidermidis Creates a biofilm Vancomycin

Prosthetics

3. staphylococcus Second most common cause of uti in women Fluoroquinolones

saphrophyticus Tmp-smx

4. staphylococcus pyogenes Impetigo contangiosa Penicillin G

Erysipelas
GAHBS Cellulitis
Pharyngitis- most common
Scarlet fever/ second disease- centrifugal rash,
pastia’s line
Strep toxic shock syndrome
Necrotizing fasciitis- fourniers gangrene
Acute rheumatic fever
Apsgn

5. streptococcus agalactiae Uti in preggo Penicillin G

Neonatal pneumonia, sepsis and meningitis
GBS Endometritis Penicillin G and
aminoglycoside for serious
infections

6. group d strep Uti in catheters Penicillin plus gentamycin

Biliary tract infections
Git surgeries with cardiac complications Vanco for pen resistance

Linezolid for vanco

resistance

7. streptococcus pneumonia Pneumonia- mc in adults, rust colored sputum Penicillin G

Otitis media- mc in child
Bac meningitis- mc in adults Levofloxacin or vanco with
Sinusitis ceftri for pen resistance
Septic shock

8. viridans streptococci Dental carries Pen G with aminoglycoside

Subacute bacterial endocarditis (gentamycin)
Brain absecess
Vanco for pen resistance

Linezolid for vanco

resistance
9. bacillus anthracis Cutaneous anthrax Cutaneous: Ciprofloxacin
Inhalation anthrax
Gastro anthrax Inhalation/gastro: Cipro doxy
with (rifam, vanco, pen,
Medusa head morphology in culture imipenem, clinda, clarith)

10. bacillus cereus Emetic form:Fried rice Food poisoning- sympto tx

Diarrheal form: meat vegs
Ophth: Vanco, clinda, cipro,
Opthalmitis- soil contaminated object, loss of light genta
perception within 48 hrs

11. clostridium tetani Muscle spasm Metronidazole or penicillin

Lock jaw
Risus sardonicus
Opisthotonus

Neonatal tetanus- 3 to 28 days of life becomes rigid

and has spasm

12. clostridium botulinum Food born – diplopia, mydriasis ptosis Trivalent botulinum antitoxin
Infant botulism- honey, floppy baby syndrome Immunoglobulin
Wound botulism
Metronidazole

Penicillin

13. clostridiuom perfringens Gas gangrene Penicillin for gas gangrene

Food poisoning- enterotoxin, water diarrhea with
cramps, resolves in 24 hrs Supportive for food
poisoning

14. clostridiuom difficile Psuedomembranous entercolitis Metronidazole

Antibiotic use- clinda cephalosphrins and ampi Oral vanco

Toxic megacolon

15. corynebacterium Pseudomembrane Penicillin or erythromycin

diptheriae Diphtheria
Myocarditis- av condution block dysrhythmia
Neural involvement- GBS peripheral nerve palsies

16. listeria moncytogenes Granulomatosis infanseptica- late miscarriage, birth Apmi +- genta
complicated by sepsis, multi organ abscess
Tmp-smx
Late onset listeriosis- meningitis, meningoenceph

Adult listeriosis- second most common cause >50 yo,

mc in immunocompromised

17. actinomyces israelii Oral/facial absecess penicillin

Follows dental caries/extraction
PIDS from IUDS
18. Neisseria meningitides Meningitis- mc 2-18 yo Penicillin

close quarters- dorm military Meningococcemia- purpura fluminans Ceftriaxone or cefotaxine for
camps meningococcal and
Waterhouse- friderichsen syndrome- most severe form septicemia
of meningo
Rifamp/cipro- prophylaxis

19. Neisseria gonorrhea Gonococcal urethritis Ceftriaxone+ doxy

Cervical gonorrhea
co infection with clam Gonococcal arthritis- mcc of septic arthritis in sexually Erythro- baby
trachomatis active individuals
Ophthalmia neonat
Mcc of severe form of conjunctivitis

20. Moraxella (branhamella Otitis media in children Azith or clarith

catarrhalis) Sinusitis
Bronchitis Co-amox
COPD exacerbation
Oral second or third gen
cephals

Tmp-smx

21. haemophilus influenze Meningitis- mcc 3 to 36 mos, sensorineural hearing Co amox

(HIB) loss, mental retard, seizures, deafness, death
Actute epiglottitis- mcc, thumb sign on xray Ceftri for meningitis
Pneumonia
Cellulitis Rifamp for close contacts
Septic arthritis

22. bordetella pertussis Whooping cough/tuspirina Erythromycin

7-10 days incubation period
Household- erythromycin
catarrhal phase
- 1-2 weeks, sipon etc, highly contagious,
antibiotics most effective

paroxysmal phase
- 2-4 weeks, whoop, antibiotics ineffective

convalescent phase
- 3-4 weeks diminished cough
- complications- seizures pneumonia, enceph

23. legionella pneumophila Pontiac fever Azithromycin

Levoflox
Atypical pneumonia doxycycline
- confusion
- non bloody diarrhea
- hyponat
- Proteinuria
- Hematuria
24. e. coli Neonat meningitis UTI: ampi or sulfo
Uti Meningitis: 3rd gen cephals
Nosocomial sepsis
Diarrhea Aminoglycosides
Etec- travelers fluoroquinolones
Epec- watery diarrhea long duration in infants
Eiec- bloody diarrhea
Ehec/stec- 0157:H7, undercooked meat, shiga like
toxin , hemorrhagic colitis, HUS

25. shigella spp Bacillary dysentery Flouroquinolones

.
s. dysenteriae mcc epidemic Azith
dysentery Tmp-smx
s. sonnei mcc bacillary
dysentery

26. vibrio spp. Shooting star/ fast darting motility Tetra azith shortens duration

v. cholerae- fecal oral route Washerwoman sign Parahemoliticus vulnificus:

Rice watery stools minocycline or cefotaxime
v. parahemoliticus
contaminated raw seafood

v. vulnificus- shellfish
handlers

27. campylobacter jejuni Mcc of bacterial gastroenteritis Symptomatic tx

Associated with GBS
curved comma shaped, gram Reactive arthritis Eryth for severe
neg rod with single polar - urethritis
flagellum - uveitis
- arthritis

28. helicobacter pylori PUD-mcc Triple therapy:

Omeprazole
Associated with gastric carcinoma, malt lymphoma Clarithromycin
Amoxicillin or metro

Quad therapy
Tetra
Omep
Metro
Bismuth subsaliculate

29. klebsiella pneumoniae Necrotizing pneumonia- friedlanders pneumonia, mcc Culture guided tx
in alcoholics, currant jelly sputum Cephals
Uti Aminoglycosides

30. proteus mirabilis Complicated uti assoc with nephrolith Ampi

Tmp-smx
31. pseudomonas aerginosa Skin and soft tissue- hot tub folliculitis, green nail Antipseudomonal penicillins-
syndrome. ticarcillin, piperacillin

Bone and cartilage infections- pubic osteomyelitis with Penicillin + beta lactam
iv drug users inhibitor- ticar- clavulanate,
Ear- mcc of otitis externa pip taz

Pneumonia- necrotizing, fleur de lis pattern 3rd gen cephals- ceftazidime

High risk cap- bronchiectasis, cystic fibrosis 4th gen cephals- cefepime
Git infections, typhlitis
monbactam- aztreonam
Shanghai fever
carbapenems- imipenem,
rd
Uti- mcc 3 nosocomial uti doripenem, etrapenem

Sepsis- ecthyma gangrenousum, febrile neutropenia flouroquionolones-

ciprofloxacin

suitable combinations-
ceftazidime+ amik
piperacillin + amik
aziocillin+ amik

rifamp for refractory cases

32. bacteriodes fragilis Abdominal abscess Metronidazole- doc

Peritonitis
predominant anaerobe of the Pericarditis Clinda
human colon Endocarditis Chlorphen
Cerebral abscess Carba
spreads to blood or bowel or 2nd gen fq
peritoneum during bowel
trauma, perforation or surgery.

33. yersina enterocolitica Mesenteric lymphadenitis

Unpasteurized milk Pseudoappendicitis

Acute enterocolitis

34. brucella spp Brucellosis- undulating fever (fever peaks in the Doxcy + genta or strep or
evening normal in the am) rifamp
dogs, cattle,pigs, goats
direct contact with livestock or
aborted placentas

35. Francisella Tularensis Tularemia Streptomycin DOC

rabbits and squirrels Ulcergrandular- ulcer develops at the bite site with Genta
swelling of the focal lymph node doxy

Pneumonia
Oculoglandular
Typhoidal
36. Yersinia pestis Bubonic plague- bubo Strepto or genta
Septicemic plague
most virulent bacteria! Pneumonic plague Doxy

wild rodents, city rats,

squirrels and prairie dogs in
the us

37. pasteurella multocida Wound infection may progress to nearby bones and Pen G
joints
bite from cat or dog Doxy
human bite: eikenella 3rd gen cephals
corodens

38. mycobacterium Exudative, granulomatous lesions PPD

tuberculosis Primary complex- ghon focus >5 Immunocom
Secondary complex- simon focus >10 chronic
>15 all others
mycobacterium avium
intracellular complex (MAC)- category 1
aids px with cd4< 50 new, extraPTB
- 2hrze/4hr

category 1a
new ExtraPTB in cns/bones/
joints
- 2hrze/10hrze

cat 2
previously treated, relapse,
extraPTB
- 2hrze/1hrze/5hre
-
cat 2a
previously treated, relapse
ExtraPTB in cns bones and
joints
- 2hrze/1hr/9hre

Rifampicin resistant or
multidrug resistant -
pyrazinamide, kanamycin,
levofloxacin, prothionamide,
cycloserine, streptomycin for
18 months!

Extensively drug resistant-

individualized based on DST
and previous tx
40. mycobacterium leprae Hansens dse- mcc crippling of the hand Rifampin
Ulnar and median- clawed hand Dapsone
Posterior tibial- plantar insensitivity and clawed toes
Common peroneal- foot drop Lepromatous leprosy-
rifampin dapsone
Erythema nodusum- tender red nodules or humps on clofazimine
both shins tx with thalidomide

41. mycoplasma pneumoniae Atypical pneumonia-mcc Macrolides- erythro, azith,

Tracheobronchitis clarith
no cell wall Extra pulmonary manifestations:
cholesterol in membrane - SJS- mcc Tetra- doxy
dome shaped colonies forming - Erythema multiforme
fried egg or mulberry - Hemolysis Quinolones- cipro, levo
appearance - Raynauds
- GBS Pen and cephalos do not
work no cell wall!

42. treponema palladium Primary S. Benzathine Pen G

- painless chancre Erythromycin
coiled spirochete Secondary S. Doxycilin
dark field microscopy - macupapular rash on palms and soles
VDRL, PRP- screening test - condylomata lata- warts after 1-3 months Jarish herxheimer reaction-
Latent S. acute worsening of
FTA-ABS, TPHA- - 25% may relapse to secondary symptoms after pen is started
confirmatory test tertiary syphilis
- gumas
t. palladium- venereal - aortitis
t. pertenue- yaws - tabes dorsalis- Argyll Robertson pupil- can
t. endemicum- bejel accommodate but does not react
t. carateum- Pinta - dementia paralytica
congenital syphilis
- snuffles/ saddle nose
- saber shins
- mulberry molar
- Hutchinson triad (Hutchinson teeth,
senosineural hearing loss, interstitial keratitis)
- Rhagades
- Higoumenakis sign (enlargement of the sternal
portion of the clavicle)
- Synovitis
- Pulmonary hermorrhage- mcc death

43. borreliella burgdoferi Lyme disease Early- doxy- DOC, amox,

Stage 1- early localized stage cefuroxime
white footed mouse/ white tail Erythema chronicum migrans
deer Late-iv pen, ceftriaxone
Stage 2- early disseminated stage
ixodes ticks Multiple ECM, bells palsy, av block, myocariditis,
arthritis of large joints

Stage 3- onion skin lesion, acrocderamtitis chronica

atrophicane, enceph
44. leptospira interrogans 2-20 days incubation period Mild- doxy, ampi, amox

spiral shaped with hooks on Acute leptospiremic phase- spiking temps, headaches, Severe- penG, ampi, ceftri,
both ends calf tenderness, conjuctival suffusion cefox

infected urine open wound Immune leptospiruric phase- emergence of IgM,

hx of wadding in flooded aseptic meningitis, pulmonary involvement (snowflake
waters lesion), glumerolonephritis
hx of exposure to animals
(butchers) Weils syndrome- bleeding jaundince uremia, orange
skin cast
leptomat-gold standard Mcc respi failure due to massive pulmonary
hemorrhage

45. chlamydia trachomatis Trachoma- leading infectious disease of blindness, Genital and eye- doxy
chronic conjunctivitis- halberstader-prowazek
uses ATP inclusions Erythro-infants

Genital tract infections- mcc of std Std- ceftriaxone

Neonatal pneumonia Azith- systemic

Stocato cough

Lymphogranuloma venerum
Buboes
+ frei test

46. chlamydophilia Atypical pneumonia Doxy

pneumoniae erythro

taiwan acute respi agents

47. chlamydophila psittaci bird fanciers disease- pneumonia, malaise, anorexia, azith
photophobia
bird fanciers disease from
parrots parakeets macaws
cockatiels
48. dermatophytes Inflamed circular borders containing papules and Topical imidazole
vesicles surrounding a clear area of skin
trichophyton,microsporum,epi Oral griseofuluvin for tinea
dermophyton – skin hair and inguium and tinea capitis
nails t. corporis- ringworm
t. cruris- jock itch
t. pedis- athletes foot
t. capitis- scalp
t. unguium- nails
t. manum
t. barbae- facial hair

49. malassezia furfur Pityriasis versicolor- hyperpigmented or Dandruff shampoo- selenium

hypopigmented macules on patches of skin localized in sulfide
basidomycete the stratum corneum
short hyphae yeast like cells- Topical imidazole
conidia
spag and meatballs
50. sporothrix schenkii Local pustule or ulcer with nodules along lymphatics Cutaneous- postassium
after a punctured wound iodide
cigar shaped, asteroid bodies Oral itraconazole
Cutaneous and disseminated form
on culture- fine septate Systemic
hyphae, daisy like clusters of Ampho B
conidia

rose thorns
rose handlers/ gardeners

51. coccidiodes immitis Valley fever- common in Filipino living in latin and Ampho B
southwest usa Itraconazole
desert areas of the
southwestern use and northern -influenza like illness, erythema nodusum, lung Meningitis- fluconazole
mexico infiltrates, arthralgias, meningitis

arthrospores form spherules

filled with endospores of
coccidiodes

mode of infection is inhalation

52. histoplasma capsulatum Histoplasmosis- chronic pneumonia Ampho B

Itraconazole
endemic in the missisipi river Erythema nodosum
and ohio valleys Meningitis- flucomazole
Tongue ulcerations
bird droppings bat guano

inhalation thru microconida

develop into budding inside
macrophage, spreads to liver
and spleen

53. blastomyces dermatitidis Blastomycosis Itraconazole

Chronic pneumonia
inhalation on conidia Ulcerated granulomas Ampho B
eastern and central US Verrucous skin leisions that look like CA
Lytic bone lesions
round yeast with broad Prostatitis
based bud

54. paracoccidiodes Paracoccidiodomycosis itraconazole

brasilinesis Chronic pneumonia
Painful ulcers on the mouth and nose
restricted to central and south 30-50 yo male
America

thick yeast with multiple

buds in wheel configuration
mariners wheel
55. Candida albicans Oral thrush Oropharyngeal and
esophageal- nystatin swish
oval yeast with single bud or Vulvovaginitis- cottage cheese and swallow
as psuedohyphae
Skin infections- satellite lesions Skin- clotrimazole

Diaper rash Disseminated- ampho B

Intertrigo
Onychomycosis Prophy- fluconazole

Immunocomp host- psuedomembranouse esophagitis,

subcutaneous nodules, right sided endocarditis

56. Cryptococcus neoformans Cryptococcosis Ampho b + flucytosine

-lung infection, meningitis, enceph followed by fluconazole
bird or pigeon droppings soap bubble leisons

oval yeast with narrow Phrophy- fluconazole

based bud surrounded by a
wide polysaccharide capsule

predisposing factors:
antibiotic use, steroid,
transplant, chemo, aids

57. aspergillus spp Allergic bronchopulmonary aspergillosis- igE Allergic bronchopulmonary

mediated, expectoration of brownish bronchial plugs aspergillosis- corticosteroids
fumigatus, flavus, niger
Aspergilloma- fungus ball Invasive- voriconazole,
septate hyphae that forms a caspofungin
v shape Invasilve apser- necrotizing pneumonia, cresent shape
sign xray Posaconazole- for prophy of
inhalation of airborne conidia invasive asper and candida
Aflatoxin- liver CA for severely
immunocompromised

58. Rhizopus Mucormyosis- dka, neurtopenic patients, fungi in Ampho B

Rhizomucor cribiform palate,
Mucor Rhino-orbito- cerebral infection
Black necrotic eschar on face
Broad non septated
branching hyphae right
angle 90

59. pneumocystis jirovecii pneumocystis jirovecii pneumonia- Tmp-smx

occurs when cd4<200
disc shaped yeast, often aids defining illness Sulfa allergies- pentamidine
exsist in clusters, contains frothy exudate that blocks oxygen exchange Dapsone
several intracystic bodies bilat ground glass infiltrates Atovaquone
 Parasitology
Protozoa Infective stage Diagnostic stage Spectrum of disease Treatment
1. entamboeba Mature cyst Troph- found in Amebic colitis- Carrier state
histolytic diarrheal stools, dysentery without fever, • Diloxanide furoate-
nucleus has small flask shaped colon doc
central nucleus and • Iodoquinol
most invasive parasite fine chromatin Ameboma- • Paromomycin
among entameba granules granulomatous lesion at
cecal or rectosigmoid Amebic colitis:
pseudopod-forming Cyst- non diarrheal areas • Metronidazole
non flagellated stools has 4 nuclei • Tinidazole
protozoa Amebic liver abscess- • Diloxanide furoate
postersuperior aspect of • Paromomycin
fecal oral the right lobe
Mc extraintestinal form
Amebic liver abscess:
• Metronidazole
• Tinidazole

2. giardia lamblia Cyst Throph- diarrheal Acute infection- metronidazole

stools, pear shaped, 2 abdominal pain, watery
flagellate that lives in nuclei, 4 flagella, foul smelling, flatus like
the duodenum, suction disk rotten eggs, no fever
jejunum and upper
ileum Cyst- diarrheal and Chronic- constipation
formed stools weight loss steatorrhea
falling leaf motility

fecal oral

3. cryptosporidium Oocyst Oocyst in kinyoun Self limiting non bloody Nitrazoxanide

hominis acid fast diarrhea

thick walled oocyst

4. balantidium coli Cyst Large ciliated troph Balantidial dysentery- Tetracycline DOC
with a V shaped locally invasive causing
only ciliated nucleus in the stool colonic ulcers (round metronidazole
protozoan that causes based wide neck ulcers)
human disease

pigs are main

reservoir
5. trichomona Troph Troph in wet mount Trichomoniasis- watery Metronidazole 2g
vaginalis foul smelling greenish
discharge, itching and
exsist only as troph burning.
pear shaped
flagellated, jerky Strawb cervix
movement
ping pong
transmission

6. plasmodium spp Sporozites Troph Destruction of rbc Chloroquine- malariae

Enlarged spleen and falci
anopheles minimus
flavirostris Chlorquine + primaquine-
Punctuate dots: ovale and vivax
Vivax and ovale-
punctuate granulations, Quinine + doxy/
schuffner clindamycin- falciparum

Falciparum- coarse Artesunate + doxy/clinda

granulations, maurer or mefloquine/ malarone-
falciparum
Malariae- fine dots,
zieman
Prophylaxis

Falci- malignant tertian Chlorquine- areas without

Malariae- benign resistance to falci
quartan
Malarone/ mefloquine –
areas with resistance to
falci

Doxy- multidrug resistant

to falci

Primaquine- terminal
prophy for ovale and
vivax

7. toxoplasma Fecal oocysts Cresent shaped Immunocompetent- Sulfadiazine+

Troph asymptomatic pyrimethamine

IgM Immunocompromised- Sulfa allergies- clinda +

Enceph, brain abscess pyrimethamine
Cyst maybe seen in seen as multiple ring
the tissue enhacing lesions

Congenital toxo-
abortion, still birth,
neonat with hydroceph,
enceph, choriorentinits
and hepatosplenomegaly
8. leishmania spp Promastigotes Amastigotes Tropicana, Mexicana or Sodium stibogluconate
oriental sore-ulcerating
bite of a female sand single or multiple skin Second line- ampho B
fly sores pentamide

Brailiensis or espundia-
attacks the mucosal
dermal junction of the
mouth and nose

Donovani or kalazar-
infects macrophage
migrates to liver and
spleen, hepatomegaly

9. babesis microti Intraerythocytic ring Babesiosis Mild to moderate-

shaped trophozite in Flu like symptoms atovaquone+ azith
ixodes tick tetrads in a form of Hepatosplenomeg and
maltese cross anemia may occur Severe- quinidine + clinda

10. cyclospora Spherical oocyst Watery diarrhea Tmp-smx

cayetanensis

fecal oral
11. isospora belli Oocyst Oocyst in fecal Immunocompromised Tmp-smx
specimens px- chronic profuse
watery diarrhea

12. trypanosoma Metacyclic Tryposmastigote in Cardiac muscle is the Doc for actute- nifurtimox
cruzii trypomastigote blood smear most frequently affected

feces of reduviid bug Bone marrow Actute phase- chagoma,

aspirate unilateral palberal
Culture swelling, resolves
Xenodiagnoses around 2 months

Chronic form-
myocarditis dilated
cardiomyopathy
Megacolon

Leading cause of CHF

in latin America
13. trypanosoma Metacyclic Tryposmastigote in Sleeping sickness as a Suramin for blood borne
brucei trypomastigote blood result of demyelinating
enceph Melarsoprol for CNS
tsetse fly painful bite penetration
Trypanosomal chancre

Winterbottoms sign-
enlargement of the
posterior cervical
lymphonodes

Kerandels sign- deep

parasthesia

Morula cells of mott-

plasma cells with
cytoplasmic
immunoglobulin

14. acanthamoeba Troph Occurs in imc Pentamidine

castellani
Keratitis Ketoconazole flucytosine
mc in contact lense Granulomatous amenic
enceph

15. naegleroa fowleri Troph Penetrate nasal mucosa Ampho B

and cribiform plate
fresh water lakes
Primary amebic enceph

16. dinoflagellates Facial paralysis total Supportive

paralysis and resp
red tide failure in 15 mins- Neostigmine and
mc in PH pyrodinium saxitoxin edrophonium to improve
bahamense var muscle weakness
compressum Facial paralysis, slurred
speech ataxia, diarrhea
in 15 minutes-
brevetoxin

Diarrhea, n&v,
abdominal pain in 30
mins- okadiac acid

Diarrhea, short term

memory loss, seizures in
30 minutes- domoic
acid