selection of antibiotics for empiric therapy in clinical practice linda l. van etta, md, facp

Selection of Antibiotics forSelection of Antibiotics for Empiric Therapy in Clinical Practice Empiric Therapy in Clinical Practice

Linda L. Van Etta, MD, FACP

Clinical presentation

Usual pathogens

Sensitivity of pathogen(s) to antibiotics

Drug/host interactions(allergies, renal & liver function,distribution in body, route, cost,duration of therapy)

Please remember:Please remember:

the antibiotic choices listed for each diagnosis are represenative. Different hospitals and clinics may use other agents based on their antibiograms of their organisms or based on their purchasing group

All choices are for empiric therapy. Antibiotic therapy is altered based on culture results

Central Nervous SystemCentral Nervous System

Bacterial Meningitis - Neonate Bacterial Meningitis - Neonate or Infantsor Infants

Clinical presentation: poor feeding, irritability, fever, lethargy

May not have nuchal rigidity


Strep, group B or D

Enterobacteriaceae

H. influenzae

Listeria

Meningococci

Pneumococci


Cefotaxime

+ Ampicillin

+ Dexamethasone

Bacterial Meningitis - AdultBacterial Meningitis - Adult

Clinical presentation- headache, fever, confusion

Nuchal rigidity


Meningococci

Pneumococci

Listeria


Ceftriaxone or cefotaxime

+ Vancomycin

+ Dexamethasone

Brain AbscessBrain Abscess

Clinical presentation- often stroke like picture with focal neurological deficits, headache

May not be febrile!


Streptococci (60-70%)

Bacteroides (20-40%)

Enterobacteriaceae (25-33%)

Staph aureus (10-15%)

HIV (+) = toxoplasmosis


Ceftriaxone or cefotaxime

+ Metronidazole

EncephalitisEncephalitis

Clinical presentation- confusion, headache, may have fever

Exposure history, season of year


Herpes simplex arboviruses rabies parasitic


Acyclovir (HSV) Others- symptomatic treatment only

Respiratory TractRespiratory Tract

Otitis MediaOtitis Media

Clinical presentation- ear pain, may have fever

Tympanic membrane-red, cloudy fluid behind

Otitis MediaOtitis Media

Pneumococci (25-50%)

H. influenzae (15-30%)

B. catarrhalis (3-30%)

Staph aureus (1%)

Group A strep (2%)

“Sterile” (35%, viral)

Otitis Media (choose one)Otitis Media (choose one)

Amoxicillin Erythromycin Trimethoprim/Sulfamethoxazole Amoxicillin/Clavulanic acid Cefuroxime azithromycin 3rd generation oral cephalosporins (Cefaclor)

PharyngitisPharyngitis

Clinical presentation- sore throat, may have fever

PharyngitisPharyngitis

Group A, C, G strep

“Viral”

EBV

Pharyngitis- for lab proven Pharyngitis- for lab proven streptococcal infection (choose streptococcal infection (choose one)one)

Penicillin

Erythromycin

Clindamycin

Treat for 10 days

Pneumonia: Community-acquiredPneumonia: Community-acquired

Clinical presentation- cough, fever, sputum production, occ. dyspnea

Infiltrate on CXR

Pneumonia: Community-acquiredPneumonia: Community-acquired

Pneumococci H. influenzae Mycoplasma pneumoniae Legionella Viral:

Hanta influenza others

Pneumonia: Community-acquired Pneumonia: Community-acquired (choose one)(choose one)

Doxycycline Respiratory fluoroquinolone:

moxifloxacin,gatifloxacin,levofloxacin

Ceftriaxone or Cefotaxime + azithromycin

Piperacillin / tazobactam combined with a resp. fluoroquinolone for severe cases

Influenza-rimantadine or oseltamivir

Pneumonia: Hospital-acquiredPneumonia: Hospital-acquired

Clinical presentation- cough, fever, sputum production developing after >72 hours in the hospital


Pseudomonas sp.

Klebsiella sp.

Enterobacter sp.


Cephalosporin, 3rd generation or anti-pseudomonal penicillin

Combined with

Cipro or aminoglycoside

Cystic FibrosisCystic Fibrosis

Pseudomonas aeruginosa*

Staph aureus

Burkholdia (Pseudomonas) cepacia

Cystic FibrosisCystic Fibrosis

Tobramycin- inhaled

AP penicillin or ceftazidime

Ciprofloxacin

(always use 2 drugs)

TMP/sulfa (for Burkholdia)

HIV / AIDS PatientsHIV / AIDS Patients

Clinical presentation

Organisms

Antimicrobial agents


Pneumocystis

(R/O TB)


TMP/sulfa or

Clindamycin + primaquine or

Atovaquone or

Dapsone + trimethoprim

Always use steroids

Genitourinary TractGenitourinary Tract

CystitisCystitis

Clinical presentation- urinary frequency, dysuria, hematuria, urgency

CystitisCystitis

Enterobacteriaceae (E. coli)

Staph saprophyticus

Enterococcus

Cystitis (choose one)Cystitis (choose one)

TMP/SMX

TMP

Ciprofloxacin

3 day treatment course

PyelonephritisPyelonephritis

Clinical presentation- fever, flank or back pain, hematuria

PyelonephritisPyelonephritis

Enterobacteriaceae

Enterococci

Pyelonephritis (choose one)Pyelonephritis (choose one)

TMP/SMX

Cephalosporin (3rd) or AP Pen

Gentamicin

Ciprofloxacin

Treat for 2 weeks

ProstatitisProstatitis

Clinical presentation- perineal pain, low back pain, dysuria, frequency, may have fever and chills

Prostatic tenderness on rectal exam


Enterobacteriaceae

Pseudomonas sp.

Chlamydia and gonoccocus in younger patients


Tetracycline

TMP/SMX

Ciprofloxacin

Ofloxacin

UrethritisUrethritis

Clinical presentation-dysuria, frequency

UrethritisUrethritis

Chlamydia trachomatis

Urethritis (choose one)Urethritis (choose one)

Tetracycline / Doxycycline

Ofloxacin

Azithromycin

Salpingitis (PID)Salpingitis (PID)

Clinical presentation-pelvic or lower abdominal pain, fever

Tenderness and possible mass on pelvic exam


Gonococcus

Chlamydia

Bacteroides

Enterobacteriaceae

Streptococci


Doxycycline + Ceftriaxone + Metronidazole

or Cefoxitin + doxycycline

or

Ofloxacin + metronidazole

Gastrointestinal TractGastrointestinal Tract

Cholecystitis / CholangitisCholecystitis / Cholangitis

Clinical presentation- RUQ pain, fever, nausea

Tenderness in RUQ on exam


Enterobacteriaceae (68%)

Enterococci (14%)

Cl. perfringens (7%)

Bacteroides (10%)


Ceftriaxone + Metronidazole

AP Pen Metronidazole

DiverticulitisDiverticulitis

Clinical presentation-left, lower abdominal pain with fever and diarrhea or bloody stools

Tenderness over LLQ on abdominal exam

DiverticulitisDiverticulitis

Enterobacteriaceae

Bacteroides sp.

Enterococci

Diverticulitis (choose one combo)Diverticulitis (choose one combo)

Gentamicin + Clindamycin

Ceftriaxone + metronidazole

AP Pen + Metronidazole

Amoxacillin/clavulanate

Ciprofloxacin + metronidazole

TMP/SMX + metronidazole

Dysentery / DiarrheaDysentery / DiarrheaSevere, fever, or bloodySevere, fever, or bloody

Clinical presentation- diarrhea, may be bloody, may have fever


Shigella sp.

Campylobacter jejuni

Salmonella

E. coli 0157:H7


Ciprofloxacin

TMP/sulfa, erythromycin

Do not treat E coli 0157-increases risk of complications

Dysentery / DiarrheaDysentery / DiarrheaMild or moderateMild or moderate

Clinical presentation – diarrhea, no fever usually, no bloody stools


Enteropathogenic E. coli

Rotaviruses

Norwalk agent


(fluids)

(antimotility agents)

Pseudomembranous enterocolitisPseudomembranous enterocolitis

Clinical presentation-diarrhea, may be bloody

Tenderness on abdominal exam Risk of developing toxic megacolon May develop without antibiotic

exposure, but usually associated


Clostridium difficile


Metronidazole

or

Vancomycin (oral)

Bone and Soft Tissue InfectionsBone and Soft Tissue Infections

CellulitisCellulitis

Clinical presentation- swelling, redness, painful soft tissue area, may have fever

CellulitisCellulitis

Group A strep

Staph aureus

Cellulitis (choose one)Cellulitis (choose one)

Clindamycin

Nafcillin or Oxacillin

Cefazolin / Cephalothin

Penicillin G

Septic Arthritis - AdultSeptic Arthritis - Adult

Clinical presentation- painful, swollen, warm joint


Staph aureus

Group A strep

Gonococci

Pneumococci

Borrelia burgdorferi (Lyme)



or

Ceftriaxone (neg. rods) or Cefotaxime

Treat for 4 weeks

Consider Vancomycin if MRSA problem locally

Osteomyelitis (adults)Osteomyelitis (adults)

Clinical presentation- bone pain, may have chronic, draining wound or sinus over the site

Often history of trauma or previous surgery at site

Osteomyelitis (adults)Osteomyelitis (adults)

Staph aureus

Osteomyelitis (adults)-choose oneOsteomyelitis (adults)-choose one


Vancomycin (for MRSA concern)

Cephalothin (1st generation)

Clindamycin

Puncture FootPuncture Foot

Pseudomonas aeruginosa

Puncture FootPuncture Foot

AP Pen or Ceftazidime +

APAG or FQ

Bacterial EndocarditisBacterial Endocarditis

Bacterial Endocarditis - AcuteBacterial Endocarditis - Acute

Clinical presentation- fever, night sweats

Heart murmur on exam


Viridans strep (30-40%)

Staph aureus (20-35%)

Group D strep (5-18%)


Penicillin G or Ampicillin +gentamicin

Nafcillin +rifampin

Vancomycin

Case studiesCase studies

7 y.o. Girl7 y.o. Girl

Chief Complaint Dysuria and urinary frequency x 2 days No fever, flank pain, trauma, hematuria (gross),

or emesis

Physical Exam Mild suprapubic tenderness T-37.0, P-71

7 yr old girl7 yr old girl

Dx?

Tests?


UA 100-200 WBC/hpf 5-10 RBC/hpf

Urine Gram Stain 15-25 gram negative rods/hpf

Specimen sent for culture

RX: ____________________


Culture Grew

>100,000 ml E. coli sensitive to amoxicillin, sulfa, cefazolin, ciprofloxacin


Recommended

IVP

Voiding cystogram

Cystoscopy

27 y.o. Male Pediatric Resident27 y.o. Male Pediatric Resident

Chief Complaint Cough, chest pain, fever x 2 days, headache

History of Present Illness “URI” symptoms for several days Developed nonproductive cough and fever Day before admission noted right-sided

pleuritic pain and cough productive of blood-tinged sputum


Physical Exam

Moderately ill

VSS, Temp - 103ºF

Chest - fine, moist rales RLL posteriorly

27 yr old male pediatric resident27 yr old male pediatric resident

Dx? Tests?

27 yr old pediatric resident27 yr old pediatric resident

WBC-8,700/ul Legionella urinary antigen-neg Pneumococal urinary antigen-neg C-reactive protein-4.5 mg/dL


Gram Stain (sputum) Many PMNs Few (+) cocci Occasional (-) rod

RX: ___________________


Sputum culture - grew normal flora

54 y.o. Female54 y.o. Female

Chief Complaint Pain in right leg, chills and fever

History of Present Illness Hx of phlebitis, now has chronic edema, especially

right leg 18 hours prior to admission noted pain in leg that

became progressively worse Few hours later noted redness, swelling & blisters;

then chills and fever developed


Physical Exam VSS, Temp 102.6ºF Right leg indurated, erythematous, swollen,

large bullae from ankle to knee

54 yr old female54 yr old female

Dx? Tests?


WBC-14,600 CRP-18.2 Blood cultures x 2-results pending Wound culture-moderate WBC, moderate

Gram + cocci

Rx_____________


Blood culture and culture of skin lesions grew Group A beta hemolytic streptococci

Patient improved with parenteral clindamycin and warm packs

69 y.o. Male69 y.o. Male

Chief Complaint Fever, cough, pain in left leg

History of Present Illness 10 days PTA fever and cough productive

of purulent sputum 8 days PTA severe pain left knee 7 days PTA knee swollen, very hot and

tender


Physical Exam

Acutely ill, dyspneic

VSS, Temp – 103.6ºF

Chest - rales left mid lung field, posteriorly

Left knee - swollen, tender, erythematous, hot

69 yr old male69 yr old male

Dx? Tests?


WBC-17.600 CRP-25.6 Blood cultures x 2 –results pending Creatinine-1.1 Other tests?


Arthrocentesis Turbid fluid 70,000 WBC, 95% PMNs Sugar - 15 mg% Protein - 6 grams %

Gram Stain (+) cocci, in pairs

RX: __________________


Blood cultures and synovial fluid grew

Streptococcus pneumoniae

Patient was treated with ceftriaxone 2 gms IV q 24 hrs for 4 weeks


Chief complaint : abdominal pain and fever

HPI: 3 days of increasing abdominal pain, mild diarrhea, and fever to 100.4


P.E: T-38, BP-130/72, P-96, R-19 Lungs-clear, CV- RR, no murmur Abdomen- tender with rebound diffusely,

absent bowel sounds


Dx? Tests?


WBC-18,600 with 92% neutrophils Creatinine-1.8, BUN-34 AST-24 Other tests?


CT abdomen/pelvis-diverticula of sigmoid colon with inflammatory changes, paracolonic inflammatory mass, and peritoneal fluid.

Rx:______________


Blood cultures were negative Peritoneal cultures grew-E coli, Bacteroides

species, Fusobacterium species, Enterococcus faecalis, and Enterobacter cloacae


Patient recovered after surgical resection of the sigmoid colon with formation of a colostomy and peritoneal irrigation combined with

Antibiotic therapy- metronidazole combined with ciprofloxacin and piperacillin/tazobactam for 10 days


Chief complaint: confusion HPI: lives alone, found by her friend in bed at

home this morning-confused, weak, unsteady on feet, speaking in nonsensical sentences


Physical exam: T-37, BP 122/63. P-73, R-16 Lungs-clear, CV-RR, no murmur, Abd-soft,

non-tender Neuro-neck supple, expressive aphasia,

DTRs-equal and reactive, toes down-going bilaterally


Dx? Tests?


CSF- WBC 34 with 72% mononuclear, RBC 75, glucose-64, protein-45

CSF- gram stain – few WBC, no bacteria seen

CT brain- normal Additional tests?


MRI brain- enhancement of the temporal region on the left

Rx:__________________


CSF PCR was positive for herpes simplex

Patient recovered with intravenous acyclovir-10 mg/kg IV q 8 hrs for 21 days

selection of antibiotics for empiric therapy in clinical practice linda l. van etta, md, facp

Documents

fever slide

facp slide

days slide

cxr slide

oseltamivir slide

toxoplasmosis slide

viral slide

season of year slide