Page 971 - Hall et al (2015) Principles of Critical Care-McGraw-Hill

702 PART 5: Infectious Disorders

C krusei and C glabrata are fully susceptible to fluconazole. Candida krusei recognized on routine testing. 82,83 If systemic antimicrobial agents are
is usually highly resistant to fluconazole but is uncommonly encoun- given for other reasons, they delay the development of CAB during the
tered except in patients from Hematology, Oncology, or Transplantation first 4 days, but subsequently organisms with extensive antimicrobial
unit. Candida glabrata is the most common non-albicans species and resistance become prevalent, such as enterococci, coagulase-negative
its prevalence has risen in recent years, especially in ICU, the elderly, staphylococci, Candida, and Pseudomonas species. In addition to dura-
diabetics, and cancer patients. Susceptibility of C glabrata to fluconazole tion of catheterization, older age and female sex are independently
is highly variable with MICs ranging from 0.25 to 256 μg/mL, with associated with a higher prevalence of CAB. 84
MIC and MIC of 4 μg/mL and 16 μg/mL, respectively. The majority Ascent of bacteria to the bladder from the urethral meatus occurs
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50
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of cases of C glabrata confined to the kidneys and urinary tract will be outside the lumen of the catheter, when a modern closed drainage
cured by fluconazole. A French study showed that 21.6% of ICU urinary system is used. The space between the catheter and the urethra is filled
isolates were due to C glabrata in 2006. 71 by a variable amount of fluid, mucus, and inflammatory exudate, in
For patients who have had adverse effects due to fluconazole or who which progressive ascending multiplication of organisms is presumed to
have failed fluconazole, flucytosine and intravenous amphotericin-B occur. In a small minority of patients, the organism originates from the
deoxycholate are alternatives. Flucytosine has good activity against collecting bag and ascends intraluminally. In the latter case, the collect-
most Candida isolates and is also concentrated in urine. However, when ing bag is contaminated during disconnections of the distal catheter or
used alone, resistance develops easily and treatment is limited by bone during emptying of the bag near the drainage port. Intraluminal spread,
marrow and gastrointestinal toxicity. Amphotericin-B deoxycholate is preceded by overgrowth of bacteria in the bag, is the mechanism associ-
also an effective alternative to fluconazole. Because urinary concentra- ated with most epidemics of CAB. Such epidemics are usually traced
tions of amphotericin-B deoxycholate exceed MICs for most Candida to a breakdown in Infection Control due to inadequate hand-washing,
for days or weeks following a single 1 mg/kg dose, renal and infusion- colonization of urine collection jugs, or contamination during sampling
related toxicities will be limited by the recommended short duration of of urine or manipulation of the catheter. 85-87 Catheter-associated bacte-
1 to 7 days. Lipid formulations of amphotericin-B should not be used riuria rarely causes local symptoms. The catheter limits exposure of
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because of low concentrations of the active drug in urine and renal tissue; the urethral mucosa to infected urine, preventing dysuria and urgency,
failure has been described in experimental Candida pyelonephritis. and continually decompresses the bladder, preventing urgency and fre-
Amphotericin-B deoxycholate bladder washouts, although effective for quency. However, symptoms of cystitis commonly arise after removal of
cystitis, have been largely abandoned in favor of fluconazole, 76,77 but may the catheter. 88
occasionally have a role for fluconazole-resistant species confined to The attribution of systemic symptoms to CAB with any certainty is
the bladder. Because of minimal urinary excretion, other azoles and the problematic. Fever, rigors, altered mental status, malaise, and lethargy
echinocandins are not recommended. There are animal studies and one are often attributed to CAB, with a presumption of renal involvement.
small report of success with caspofungin for Candida pyelonephritis. However, no objective test is available to prove or disprove that CAB
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However, because of limited clinical data and poor urinary concentra- has ascended to the kidneys. Flank pain and renal angle tenderness, if
tion, caution must be exercised if an echinocandin or voriconazole is present, are highly suggestive. In patients with fever initially attributed
used for renal candidiasis. to CAB, an alternative diagnosis frequently emerges over the following
For critically ill unstable patients with disseminated candidiasis, an days. A prospective study of almost 1500 hospitalized patients with
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echinocandin (caspofungin, anidulafungin or micafungin) is recom- urinary catheters, many in ICU, showed 235 cases with CAB. Seventy
mended initially over fluconazole because it covers resistant species nine had bacteremia, but almost all were vascular cannula related. Only
better, is fungicidal, and a superior outcome has been demonstrated in four patients had concordant results from urine and blood, but only one
one randomized controlled trial. In stable patients who are improving bacteremia was definitely of urinary origin, and another was possibly.
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on an echinocandin, a switch to fluconazole is desirable, when the isolate It is commonly difficult in practice to distinguish whether a patient
has been identified as a species susceptible to fluconazole (C albicans, has CAUTI or asymptomatic CAB and another cause of sepsis. Many
C parapsilosis, and C tropicalis). Fluconazole will also ensure complete patients with CAB and fever receive antimicrobial therapy directed at
eradication from the urinary tract. Duration of antifungal therapy is the urinary organism with uncertain benefit but sometimes with col-
14 days after resolution of all clinical findings, drainage of any abscess, lateral damage. In a stable febrile patient simply changing or removing
and relief of obstruction. Fungus ball requires early aggressive surgical the urinary catheter while holding antimicrobial therapy and observing
debridement and fluconazole. If access to the renal collecting system is closely is warranted. In patients without features of sepsis, screening
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available, adjunctive irrigation with amphotericin-B deoxycholate at a for CAB should be discouraged, as positive cultures commonly give
concentration of 50 mg/L of sterile water may be useful but carries a risk rise to inappropriate antimicrobial use. Although only 50% of CAB is
13
of nephrotoxicity. recognized in routine care, the majority so recognized go on to receive
inappropriate treatment. 83,89,91 Asymptomatic CAB should only be
CATHETER-ASSOCIATED BACTERIURIA treated before instrumentation of the urinary tract or in transplant and
AND CANDIDURIA neutropenic patients.
Efforts are warranted to limit the number of catheter-days, as duration of
Catheterization of the bladder is initially unavoidable in most patients use is the most important remedial factor. Urinary catheterization should
in the ICU. The National Healthcare Safety Network (NHSN) reported not be used routinely to avoid incontinence. Bedside bladder scanners may
that in 2006 to 2008 approximately 75% of patient-days in US adult ICUs be useful at confirming urinary retention before proceeding to catheteriza-
were spent with a urinary catheter in place. In the United States, the tion. The number of catheter-days can be reduced by withdrawal of the
2
Centers for Medicare and Medicaid Services have decided that CAUTI catheter as soon as the indication no longer applies. These include alert
is “a reasonably preventable complication” for which hospitals are no and stable patients who can void to a bottle or commode, patients with
longer to receive additional payment. This assertion has stimulated a anuric renal failure for whom once-a-day intermittent catheterization will
renewed interest in prevention but also raises the possibility that inap- suffice, and male patients with an intact voiding mechanism who can be
propriate screening and treatment of catheter-associated bacteriuria managed with condom drainage. Intermittent catheterization can be used
(CAB) will follow as an unintended consequence. 80 in stable patients with neurogenic bladders and in some patients with
One percent of patients will acquire bacteriuria from a single “in-out” disturbed consciousness.
catheterization. Subsequent development of CAB is time dependent. Disconnections of the collecting tube-catheter junction increase
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The incidence of CAB varies from 3% to 7% per day in prospective bacteriuria risk. Samples should always be taken by aspiration of urine
research studies, using daily urine culture, but only 50% of these are through the distal catheter or collection port, after local disinfection.

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