Hospital Acquired & UTIs

Use of Lab Tests for Dx. of Legionnaires' Disease

transtracheal aspirate culture 90% sensitivity & 100% specificity; sputum culture; DFA staining of sputum; urinary antigen testing; antibody serology

Workup for New Fever in a Hospitalized Patient History: _(1)_ Features of hospitalization: _(2)_

(1) Headache Cough Abdominal pain Diarrhea Flank pain Dysuria Urinary frequency Leg pain (2) Presence of IV devices Urinary catheter use Performance of surgical procedures Use of new medications

Legionella Infections Etiology: _(1)_ EpidemiologY: _(2)_

(1) Aerobic, gram-negative bacilli whose natural habitats are fresh-water aquatic environments May multiply in man-made aquatic reservoirs L. pneumophilia causes 80-90% of human Legionella infections (2) 3-15% of CAP'S 10-50% of nosocomial pneumonias when a hospital's water supply is colonized with organism

Hospital Infection Control

Cross-infection is particularly important & hand washing single most important measure Minimizing invasive procedures & vascular & bladder catherizations to those that are absolute necessary

Risk factors for Surgical Wound Infection

Presence of a drain Longer preoperative hospital stay Preoperative shaving of field Longer duration of surgery Presence of an untreated remote infection Higher risk- surgeon

Bacteremia & IV Device-Related Infection Treatment

Therapy should be directed at most likely cause of infection & chosen on basis of C/S If an infection is known to be related to an intravascular device or when no other source of infection is apparent, device should be removed & catheter tip sent for quantitative culture New intravascular device should be inserted at a different site

Acute Bacterial Prostatitis Diagnosis: _(1)_ Treatment: _(2)_

(1) C/S urine usually yield bacterial pathogen Vigorous prostatic massage should be avoided Gram staining of urine may be useful in guiding empiric therapy for catheter-associated cases (2) Acute prostatitis in which gram-negative pathogens detected in urine IV TMP-SMZ(160/800 mg bid) or Cephalosporin Fluroquinolone Aminoglycoside Acute prostatitis in which gram + cocci detected in urine Nafcillin(1-2 g q 4h) Catheter associated acute prostatitis Fluroquinolone, third generation cephalosporin, or an aminoglycoside until etiologic agent has been isolated & tested for sensitivity

Legionella Infections Host-specific risk factors: _(1)_ Pontiac Fever: _(2)_

(1) Cigarette smoking Chronic lung disease Advanced age Immunosuppression (2) Occurs in epidemics, with high attack rates reflecting airborne transmission

Chronic Bacterial Prostatitis Pathogens: _(1)_ Treatment: _(2)_

(1) E.coli, Klebsiella, Proteus, or other uropathogenic organisms Evidence for causative roles of Ureaplasma urealyticum and C. trachomatis is inconclusive (2) Fluroquinolones(Ciprofloxacin, 500 mg BID) have been more successful than other agents but must be given at least 12 weeks to be effective

Hospital Acquired Infections Risk factors for UTI: _(1)_ Risk factors for Primary Bacteremia: _(2)_

(1) Female sex Prolonged urinary catherization Absence of systemic antibiotics Inappropriate catheter care (2) Presence of an indwelling intravascular device Hyperalimentation

Acute Pyelonephritis Clinical Manifestations: _(1)_ Diagnosis & Treatment: _(2)_

(1) Fever, shaking chills, nausea, vomiting & diarrhea Flank pain & dysuria CVA tenderness (2) Women with symptoms characteristic of acute uncomplicated cystitis may be treated empirically Either on basis of Hx and PE alone or after confirmatory microscopy or leukocyte esterase determination

Tularemia Ulceroglandular (75-85%) : _(1)_ Oculoglandular disease: _(2)_ Pulmonary: _(3)_ Typhoidal form: _(4)_

(1) Follows skin inoculation of F. tularenesis; a papule forms & evolves into a punched-out-appearing ulcer with a necrotic base Large, tender regional LN's develop (2) Develops after inoculation into eye & presents as purulent conjunctivitis & regional lymphadenopathy (3)High mortality rate & may complicate other forms of disease or follow inhalation of organism Presents as nonproductive cough & bilateral patchy infiltrates (4) Rare in US Presents as fever without skin lesions or adenopathy

Brucellosis Epidemiology: _(1)_ Clinical Manifestations: _(2)_

(1) Humans become infected by exposure to animal tissues ( slaughterhouse workers, butchers) or by ingestion of untreated milk or milk products or raw meat (2) Acute illness after a 7- to 21-d incubation period, although incubation period may be as long as several months

Bacteremia & IV Device-Related Infection Signs & Symptoms: _(1)_ Etiologic organisms of concern: _(2)_

(1) Only presenting symptom may be fever Exit site of an existing or previous IV line should be evaluated for erythema, induration, tenderness, &/or purulent drainage (2) Candida spp. S. aureus Enterococci

Pneumonia Signs & Symptoms Non-ICU patients: _(1)_ Signs & Symptoms ICU patients: _(2)_

(1) Pneumonia should be suspected in setting of a new infiltrate on CXR, a new cough, fever, leukocytosis, & sputum production (2) Signs in ICU pts & especially intubated pts may be more subtle; purulent sputum & abnormal CXR's are common Look for change in character or quantity of sputum in an intubated pt with fever, with or without accompanying CXR changes note: **if u rn't sure, tx for both organisms. Important*

DDx of New Fever in a Hospitalized Patient Infectious Causes: _(1)_ Noninfectious Sources: _(2)_

(1) UTI Wound Infection Pneumonia Bacteremia Antibiotic-associated diarrhea caused by Clostridium difficile Decubitus ulcers Sinusitis (2) Drug fever- may occur with or without eosinophilia or rash Thrombophlebitis PTE

*Pneumonia *

*will keep ppl in hospital longest*

Etiologic Organisms in Nosocomial Pneumonia's

+Gram-negative aerobic bacilli: P. aeruginosa K. pneumoniae Enerobacter spp- +S. aureus +Viruses - RSV & adenovirus +Depending on institution, following pathogens may be of special concern: MRSA Xanthomonas spp. Flavobacterium spp. Legionella spp

Pathogenesis of UTI's

1. Bacteria gain access to bladder via urethra 2. Ascent of bacteria from bladder may follow & may lead to upper tract disease

Hospital Acquired Infections Frequency of Infections

1. UTI(40-45%) 2. Surgical wound infections(25-30%) 3. Pneumonia(15-20%) 4. Bacteremia(5-7%)

Hospital Acquired Infections

AKA Nosocomial infections Defined as a infection acquired during or as a result of hospitalization Generally manifest after 48 h of hospitalization Epidemiology -3-5 % of pts admitted to an acute-care hospital in US acquire a new infection -Translates into 2 million nosocomial infections per year with an annual cost > $2 billion

Surgical Wound Infection Index for assessing risk of wound infections developed with factors

Abdominal surgery Surgery lasting > 2 hours Contaminated or dirty-infected surgery 3 or more Dx. for one patient

Epidemiology of UTI's Can categorize as catheter-associated(nosocomial) or non-catheter-associated(community acquired)

Acute infections are very common Vast majority of symptomatic cases involve young women Sexual activity augments the risk of infection UTI's rare among men < 50

Legionella Infections Modes of transmission

Aerosolization Aspiration Direct instillation into lung during respiratory tract manipulation Direct human-to- human transmission is thought not to occur

Bacteriuria Indwelling Foley catheters

Bacteriuria develops in at least 10-15% of hospitalized pts with indwelling urethral catheters Risk of infection about 3-5 % per day of catheterization

Tularemia DX

Based on serological agglutination tests Four-fold rise in titer over 2-3 weeks is Dx of acute infection A single titer of > 1:160 constitutes presumptive evidence of infection Gram's staining of material usually yields - results; special stains & indirect fluorescent antibody may be revealing Culture & isolation difficult, pose a major risk to laboratory personnel, & should be attempted only in labs with adequate isolation techniques & experienced personnel

Brucellosis Dx.

Basis of potential exposure, compatible clinical features, & elevated levels of Brucella agglutinins In nonendemic areas a titer of > 1:160 is considered + On endemic areas a titer of 1:320 or 1:640 is significant, & IgM assays are + in early infection Most definitive evidence of infection is isolation of organism from blood or BM, optimally with special culture techniques Cultures may take up to 6 weeks to become + but ultimately are + in 50-70% of cases Samples in which presence of Brucella is suspected should be so labeled to alert lab to use special cultural techniques & to be aware of hazard posed by this material to lab personnel

Workup for New Fever in a Hospitalized Patient Laboratory Test

CBC with differential CXR Blood and urine C/S LFT's ? Abdominal studies ? Routine aerobic cultures for sputum, stool, or other relevant body fluids ? Testing of stool for C. difficile toxin in cases of diarrhea ?

Bacteriuria Clinical Manifestations

Can be asymptomatic Dysuria, frequency, urgency, & suprapubic pain 1/3 of pts with such symptoms & significant bacteriuria have concomitant clinically silent upper tract disease Remember ~ 30 % of women with acute dysuria do not have significant bacteriuria

Bartonellosis Treatment

Cat-scratch disease is generally self limited & resolves spontaneously Azithromycin 500 mg PO on day 1, 250 mg PO on days 2-5 for disseminated disease Ciprofloxacin & doxycycline also used

Tularemia Epidemiology

Caused by Francisella tularensis a bipolar-staining, pleomorphic bacillus transmitted to humans by insect bites, skin contact, inhalation, or ingestion of material from multiple species of wild animals In US., transmission takes place primarily through skin contact with infected wild rabbits or by tick or deerfly bite Common in Arkansas, Oklahoma, & Missouri; these states account for > 50% of U.S. cases

Plague Epidemiology

Caused by Yersinia pestis, a gram-negative coccobacillus Sporadic cases of human disease and is transmitted by bite of rodent flea, predominantly in SW USA Less commonly, plague is contracted via airborne droplets In its pulmonic form, can be transmitted from person to person

Plague Treatment

DOC for plague is streptomycin(1 g IM q 12h for 10 d) Gentamicin(1.0-1.7 mg/kg IV q8h) & tetracycline(500 mg PO or IV q 6h) are alternatives Pts with pneumonic plague should be placed in respiratory isolation & contacts should receive prophylactic tetracycline(250-500 mg PO qid) Death almost always due to a delay in Rx

Tularemia Treatment

DOC streptomycin(7.5-10 mg/kg IM q 12 h) for 7-10 d In severe infections, 15 mg/kg q 12 h may be used for first 48-72 h Gentamicin(1.7 mg/kg IV or IM q8h) also may be used

Asymptomatic Bacteriuria

Development parallels that of symptomatic infection Rare among men < 50 Common among women 20-50 Common among elderly of either sex

Primary Y. pestis pneumonia Clinical Manifestations

Develops after an incubation period of 1-4 d Acute onset of fever, chills, myalgias, headache, cough, & dyspnea CXR shows involvement of a single lobe progressing to multilobar involvement Illness is fulminant, & death occurs within 2-6 d in absence of treatment Meningitis is a serious but unusual manifestation

Urine C/S

Diagnosis of cystitis uncertain? UTI suspected Complicating factors present Colony count of > 10 5/mL in voided midstream specimen usually indicated infection In symptomatic women with pyuria, counts of 10 2-10 4/mL of E. coli, Klebsiella, Proteus, or S. saprophyticus may also indicate infection Bacteriuria to any degree in suprapubic aspirate or presence of > 102 bacteria/mL in urine obtained by catheterization

Clinical Clues Suggestive of Legionares' Disease

Diarrhea High fever(> 104) Numerous neutrophils but no organisms revealed by Gram's stain of respiratory secretions Hyponatremia(< 131 meq/L) Failure to respond to B-lactam drugs (penicillin's or cephalosporins) & aminoglycosides Occurrence of illness in an environment in which water supply is known contaminated with Legionella Onset of symptoms within 10 days after discharge form hospital

Clinical Manifestations Pontiac Fever

Disease syndrome linked to legionella Acute, self-limited, flu-like illness Characterized by malaise, fatigue, myalgias, fever, & HA Pneumonia does not develop

Cat-Scratch Disease Clinical Manifestations

Dissemination of infection is rare in immunocompetent hosts & causes meningoencephalitis, osteomyelitis, or hepatitis Conjunctival infection with preauricular lymphadenopathy is referred to as Parinaud's oculoglandular syndrome

Brucellosis Treatment

Doxycline(100 mg bid) plus gentamicin(3-5 mg/kg IV qd in 3 divided doses) x 4 weeks followed by a combination of doxycycline & rifampin 600-900 mg PO qd for 4-8 weeks Repeat blood C/S & IgG measurements should be performed every 3-6 months for 2 years

Pathogens in Uncomplicated UTI's Defined as those unassociated with catheters, urologic abnormalities, or calculi

E. coli causes ~ 80% Proteus, Klebsiella and Enterobacter account for lesser percentages of cases Staphylococcus saprophyticus causes 10-15% of acute symptomatic UTI's in young women

Surgical Wound Infections Signs &Symptoms

Erythema extending > 2 cm beyond margin of wound Localized tenderness & induration Fluctuance, drainage of purulent material Dehiscence of sutures In pts with sternal wounds, ongoing fever or development of rocking or instability of sternum may indicate need for surgical exploration of wound

Acute Bacterial Prostatitis

Etiology in non-catheter-associated cases Common gram-negative urinary tract pathogens(E. coli or Klebsiella) Etiology in catheter-associated cases Nosocomially acquired gram-negative rods or enterococci

Trench Fever Clinical Manifestations

Febrile illness recently emerged in homeless persons (in whom infection has been caused by B. quintana) & persons bitten by ticks (B. henselae) Fever, HA, & aseptic meningitis are common symptoms Bacteremia can persist for weeks

Risk Factors for UTI's

Female gender Sexual activity Pregnancy GU obstruction Neurogenic bladder dysfunction Vesicoureteral reflux Hematogenous pyelonephritis (occurs most often in debilitated pts.) Staphylococcemia or candidemia may lead to metastatic renal parenchymal infection

Common Signs & Symptomsof Brucellosis

Fever & chills Fatigue Anorexia Weight loss Sweats HA Myalgias Lower back pain Constipation Sore throat Dry cough Localized infections Osteomyelitis (LS vertebrae) Arthritis Splenic abscess Epidymoorchitis CNS infection Endocarditis

Acute Bacterial Prostatitis Clinical Manifestations

Fever, chills, dysuria, and extreme prostatic tenderness May occur spontaneously(younger men) or in association with indwelling urethral catheter Often asymptomatic Prostate usually feels normal on palpation Perineal or lower back pain or obstructive symptoms in some cases Pattern of relapsing cystitis in a middle-aged man suggest Dx & due to intermittent spread of prostatic infection

Urinary Tract Infection Signs and Symptoms

Fever, dysuria, frequency, leukocytosis, & flank pain or CVA tenderness correlate well with bladder infection or pyelonephritis in pts who have had urinary catheters in place In pts with fever alone, findings of WBCs without epithelial cells in urinary sediment or detection of leukocyte esterase or nitrite is suggestive of UTI Urine C/S + for a single organism in an asymptomatic hospitalized pt is not diagnostic of UTI

Microscopy of Urine

Finding of bacteria on a gram-stained unspun specimen indicates a colony count of at least 10 5/mL Finding of bacteriuria with leukocyte casts suggests pyelonephritis Increased WBC's with white cell casts or mixed white cell-epithelial casts are considered to be renal in origin Numbers of 30 or more white cells per high power field suggest an acute infection

Cat-Scratch Disease Clinical Manifestations

Follows a primary skin inoculation by lick, scratch, or bite of a cat B. henselae, a ting gram-negative rod, is now thought to be only causative agent Frequently a skin lesion develops after 3-5 d at primary site of inoculation Tender lymphadenopathy occurs after 1-2 weeks & persists for 3-6 weeks or longer

Pathogens in Complicated UTI's Defined as recurrent or catheter-associated infection, infections following urologic manipulation, & in setting of GU obstruction or calculi

Gram Negatives E. Coli, Proteus, Klebsiella, Enterobacter, Pseudomonas & Serratia Gram Positives Enterococci Staphylococcus aureus

Clinical Manifestations of Legionella Pneumonia

High fever Nonproductive cough GI symptoms SOB & confusion are common Chest exam reveals rales early in course & evidence of consolidation as disease progresses Abnormalities on CXR are evident on presentation but are nonspecific Pleural effusion 1/3 of cases

Hospital Acquired Infections Risk factors for Pneumonia

ICU stay Intubation Altered level of consciousness(especially with a NG tube in place) Old age Chronic lung disease Prior surgery Use of H2 blockers or antiacids

Bartonellosis Diagnosis

Identified in tissues by Warthin-Starry silver stain In cases involving immunocompromised hosts, bacteria may be isolated from cultures of blood & other sites although lengthy incubation(2-4 h) i required PCR testing of clinical specimens for definitive ID of Bartonella sp. Serology is + in 70-90% of pts with cat-scratch diseases

Pyuria

If two or > leukocytes per HPF appear in non-contaminated urine, specimen is probably abnormal.

WBC Casts

Most typical for acute pyelonephritis, but they may also be present with glomerulonephritis Presence indicates inflammation of kidney, because such casts will not form except in kidney

Legionella Infections Treatment

Newer macrolides & quinolones DOC For severely ill pts, rifampin(600 mg PO or IV q 12h) is combined with a newer macrolide or a quinolone for initial therapy Clinical response usually occurs within 3-5 d, after which pt may be switched to oral therapy to complete a 10-to 14-d course Tetracycline's & TMP-SMZ are alternative agents Pontiac fever is treated supportively, without antibiotics

Bubonic Plague Clinical Manifestations

Rapid onset of fever, myalgias, arthralgias, & painful lymphadenopathy (the bubo) after a 2-to 6-d incubation period If left untreated, bubonic plaque may progress to sepsis, hypotension, DIC, & death within 2-10 d Secondary pneumonia develops in 10-20% of pts, characteristically with initially diffuse interstitial pneumonitis in which sputum production is scant

Tularemia Clinical Manifestations

Several different clinical syndromes, most of which are associated with fever, chills, HA, & myalgias, after a 2-to 10-d incubation period

Plague Diagnosis

Since unusual in the US., a high index of clinical suspicion & a thorough epidemiological history are required for timely diagnosis & prompt institution of specific therapy Lab diagnosis is usually based on stains & cultures of blood, sputum, an aspirated bubo, or CSF Stains reveal characteristic bipolar "safety-pin" forms Culture is usually + but requires 48-72 h Serology may serve to confirm cases

Workup for New Fever in a Hospitalized Patient Physical Exam

Skin Pulmonary Abdomen(RUQ ?) Costovertebral angles Surgical wounds Lower extremities Current or old IV sites

Pasteurella Multocida

Small gram-negative coccobacillus Transmitted by bites or scratches from animals, particularly cats & dogs Infections are characterized by rapid development of intense inflammation & purulent discharge High risk of deep tissue infections, including osteomyelitis, tendon sheath involvement, or septic arthritis

Hospital Infection Control Category-specific isolation measures

Strict Isolation for chickenpox Contact isolation for staphylococcal wound infections Respiratory isolation for untreated meningitis AFB isolation for suspected TB, with fulfillment of specific ventilation requirements Enteric precautions for C. difficle diarrhea Drainage/secretion precautions for minor wound infections Universal precautions have largely replaced blood and body fluid precautions

Treatment [pyelonephritis??]

Uncomplicated cystitis in nonpregnant women whose post treatment follow-up can be ensured Trimethoprim-sulfamethoxazole(TMP-SMZ; 4 single-strength tablets) or a quinolone Uncomplicated cystitis in nonpregnant women of longer standing or when follow-up is less reliable 3-day course of TMP-SMZ( 1 double-strength tablet bid) or quinolone Complicated cystitis in females & all males with cystitis 7-14 day course of TMP-SMZ or quinolone Acute cystitis in pregnancy 3-7 d of amoxicilin, nitrofurantoin, or a ceplalosporin For women with acute urethritis Choose treatment according to suspected pathogen Doxycycline 100 mg PO bid x 7 days for C. trachomatis For acute uncomplicated pyelonephritis 14-d course of a fluroquinolone, an aminoglycoside, or a third-generation cephalosporin TMP-SMZ also acceptable in areas where resistance to this agent among E.Coli strains causing pyelonephritis remains low Mildly symptomatic pts can be treated orally from onset All others should receive IV therapy until their condition improves Complicated UTI's Require broad-spectrum therapy(Ceftriaxone, 1 g IV q 12h) until sensitivity data become available Confirmed asymptomatic bacteriuria 7 days of treatment with an oral agent to which isolate is sensitive Recurrent symptomatic bacteruria Prophylaxis daily or thrice weekly with agents such as nitrofurantoin(50mg) or TMP-SMZ(80/400 mg)

Brucellosis

Zoonosis caused by four species of aerobic-gram-negative bacilli Brucella melitensis (most common) acquired from goats, sheep & camels B. suis acquired from hogs B. abortus acquired from cattle B canis acquired form dogs