Asymptomatic bacteriuria 無症狀菌尿症
2018-09-21 UPTODATE 建議
複雜性UTI診斷:
Diagnosis — The diagnosis of acute complicated UTI is made in the following clinical scenarios:
1. 發燒. 或其他全身性症狀. 畏寒. 神智改變.
2. 軀幹疼痛. 懷疑腎臟發炎. 通常伴隨發燒或其他膀胱炎症狀. CT可看到腎臟周圍發炎. 有時候伴隨膿瘍. 但CT正常無法排除輕微腎盂腎炎.
3. 發燒或敗血症. 排除其他感染源.. 如果沒有膿尿. 不太可能是複雜性 UTI.
●Symptoms of cystitis (dysuria, urinary urgency, and/or urinary frequency) along with fever (>99.9ºF/37.7ºC) or other signs or symptoms of systemic illness, such as chills, rigors 嚴格.嚴酷, or acute mental status changes. In such cases, pyuria and bacteriuria support the diagnosis.
●Flank pain and/or costovertebral angle tenderness in the setting of pyuria and bacteriuria. This is suggestive of pyelonephritis. Fever and typical symptoms of cystitis are usually present, but their absence does not rule out the diagnosis. CT findings that support the diagnosis include low attenuation extending to the renal capsule on contrast enhancement with or without swelling and complications such as renal abscesses. However, a normal CT does not rule out the possibility of mild pyelonephritis.
●Fever or sepsis without localizing symptoms in the setting of pyuria and bacteriuria may be attributed to UTI if other causes have been ruled out. Careful clinical assessment is necessary. The diagnosis of is unlikely if pyuria is absent.
因複雜性 UTI 住院病患. 依據病患是否可能有多重抗藥性細菌的危險因子, 決定使用的藥物種類. 依照流程圖, 先評估病患是否需要收 ICU. 是否敗血症. 是否尿道阻塞.
再來評估是否有抗藥性: 尿培養出MDR細菌. 曾經使用 FQ. BAKTAR. 廣效效 BETA-LACTAM. 三代以上的頭孢素抗生素. 曾經去高抗藥性地區旅行. (印度.以色列. 西班牙. 墨西哥). 如果以上皆否. 可選擇
CEFTRIAXONE 1gm QD.
tazocin 3.375g Q6H 或 TAZOCIN 4.5g Q6H
CIPROXIN 400 MG Q12H IV.
CIPROXIN 500 mg PO BID
CIPROXIN 1000 mg EXTENDED RELEASE QD.
CRAVIT 750 mg IV QD.
CRAVIT 750 mg PO QD.
如果懷疑是抗藥性的 Gram positive infection. 加入下列一種
VANCOMYCIN 15mg/kg. Q12H
DAPTOMYCIN,UVOM 6mg/kg QD
LINEZOLID 600 mg IV OR oral Q12H
●No risk factors for infection with a multidrug-resistant gram-negative organism (table 2) – For these patients, we favor ceftriaxone (1 gram IV once daily) or piperacillin-tazobactam (3.375 grams IV every six hours) for parenteral treatment because of their safety profile and narrow spectrum compared with other parenteral agents. Oral or parenteral fluoroquinolones (ciprofloxacin or levofloxacin) are also reasonable alternatives if the patient has not had a urinary isolate resistant to fluoroquinolones in the prior three months and the community prevalence of E. coli fluoroquinolone resistance is not known to be higher than 10 percent.
Concern for particular pathogens should further inform the choice between these options. If Enterococcus or Staphylococcus species are suspected (eg, because of prior urinary isolates or gram-positive cocci on a current urine Gram stain), piperacillin-tazobactam is preferred because it has activity against these organisms (if the patient cannot use piperacillin-tazobactam because of allergies or otherwise, vancomycin plus one of the other gram-negative agents can be used). If drug-resistant gram-positive organisms are suspected because of previous urinary isolates or other risk factors, vancomycin (for MRSA) or linezolid or daptomycin (for vancomycin-resistant Enterococcus [VRE]) should be added. If there is a risk of P. aeruginosa (eg, because of prior urinary isolates or febrile neutropenia), piperacillin-tazobactam at a higher dose (4.5 grams IV every eight hours) or a fluoroquinolone should be chosen. Other antipseudomonal agents that can be used include cefepime (2 grams IV every eight hours) and ceftazidime (2 grams IV every eight hours).
●At least one risk factor for infection with a multidrug-resistant gram-negative organism (table 2) – For these patients, we favor empiric treatment with an antipseudomonal carbapenem (imipenem 500 mg IV every six hours, meropenem 1 gram IV every eight hours, or doripenem 500 mg IV every eight hours).
Concern for particular pathogens should further inform regimen selection. If Enterococcus species or MRSA are suspected (eg, because of prior urinary isolates or gram-positive cocci on a current urine Gram stain), we add vancomycin (for MRSA) or daptomycin or linezolid (for vancomycin-resistant Enterococcus [VRE]).
Advanced cephalosporin or carbapenem combinations with beta-lactamase inhibitors (such as ceftazidime-avibactam, ceftolozane-tazobactam, and meropenem-vaborbactam) also have activity against some ESBL-producing and multidrug-resistant P. aeruginosa isolates and are effective for acute complicated UTI [29-31], but because of cost and antimicrobial stewardship concerns, they should only be used in select cases of highly resistant infections. If carbapenem resistance is suspected based on prior susceptibility testing results, an infectious diseases consult should be obtained.
Results of urine culture and susceptibility testing should be followed to ensure that the chosen empiric antimicrobial regimen is appropriate and to guide selection of definitive therapy.
complicated cystitis UTI 抗生素選擇
泌尿道感染應該使用多少天的抗生素
哪些情況需考慮作尿液培養(eMedicine連結)
Urine Culture
Urine culture remains the criterion standard for the diagnosis of UTI. Collected urine should be sent for culture immediately; if not, it should be refrigerated at 4°C. Two culture techniques (dip slide, agar) are widely used and accurate.
The 2010 Infectious Disease Society of America (IDSA) consensus limits for cystitis and pyelonephritis in women are more than 1000 colony-forming units (CFU)/mL and more than 10,000 CFU/mL, respectively, for clean-catch midstream urine specimens. Historically, the definition of UTI was based on the finding at culture of 100,000 CFU/mL of a single organism. However, this misses up to 50% of symptomatic infections, so the lower colony rate of greater than 1000 CFU/mL is now accepted. [22]
The definition of asymptomatic bacteriuria still uses the historical threshold. Asymptomatic bacteruria in a female is defined as a urine culture (clean-catch or catheterized specimen) growing greater than 100,000 CFU/mL in an asymptomatic individual.
Note that any amount of uropathogen grown in culture from a suprapubic aspirate should be considered evidence of a UTI. Approximately 40% of patients with perinephric abscesses have sterile urine cultures.
An uncomplicated UTI (cystitis) does not require a urine culture unless the woman has experienced a failure of empiric therapy. Obtain a urine culture in patients suspected of having an upper UTI or a complicated UTI, as well in those in whom initial treatment fails.
If the patient has had a UTI within the last month, relapse is probably caused by the same organism. Relapse represents treatment failure. Reinfection occurs in 1-6 months and usually is due to a different organism (or serotype of the same organism). Obtain a urine culture for patients who are reinfected.
If a Gram stain of an uncentrifuged, clean-catch, midstream urine specimen reveals the presence of 1 bacterium per oil-immersion field, it represents 10,000 bacteria/mL of urine. A specimen (5 mL) that has been centrifuged for 5 minutes at 2000 rpm and examined under high power after Gram staining will identify lower numbers. In general, a Gram stain has a sensitivity of 90% and a specificity of 88%.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2875701/
Urine culture
The diagnosis of UTI from simple cystitis to complicated pyelonephritis with sepsis can be established with absolute certainty only by cultures of urine. The major indications for urine cultures are:
Patients with symptoms or signs of UTIs;
Follow-up of recently treated UTI;
Removal of indwelling urinary catheter;
Screening for asymptomatic bacteriuria during pregnancy; and
Patients with obstructive uropathy and stasis, before instrumentation.
Urine specimens must be cultured promptly within 2h or can be preserved by refrigeration or a suitable chemical additive (boric acid sodium formate). Acceptable methods of collection are:
Midstream urine after careful washing;
Urine obtained by single catheterization;
Urine obtained by supra pubic needle aspiration; and
Sterile needle aspiration of urine from the tube of a closed catheter drainage system.
Results of cultures depend on the clinical setting in which bacteriuria occurs. For example, E. coli are found in the urine of 80-90% of patients with acute uncomplicated cystitis and acute uncomplicated pyelonephritis. Many patients with staghorn calculi harbour urea-splitting proteus organisms in their urine. Klebsiella, Pseudomonas and Enterobacter infections are commonly acquired in the hospital. The presence of Staphylococcus aureus often is a clue to concomitant Staphylococcal bacteremia, unless an underlying risk factor exists.
Micro-organisms in young men are similar to the organisms that cause uncomplicated infections in women. Enterococci and coagulase-negative staphylococci are more common in elderly men; most likely representing recent instrumentation or catheterization. C. albicans is rarely encountered except in patients with indwelling catheters, nosocomial UTIs or relapsing infections after multiple courses of antibiotics. Although the likely organism and usual susceptible patterns are sufficient to guide initial empiric therapy of uncomplicated UTI, adequate treatment of acute bacterial pyelonephritis and complicated UTIs necessitates precise therapy based on isolation of the causative bacterium and its antimicrobial susceptibility.[13]
Significant bacteriuria
It is defined as the presence of 100 000 or more colony forming units (CFU) per ml of urine. This Kass[1] criteria has been questioned and bacterial counts of 102 or more organism per ml particularly when accompanied by pyuria (>10 wbc/mm3) provide impressive evidence of urinary tract infection in symptomatic young women.[2] The Infectious Disease Society of America (IDSA) gave a slightly more relaxed consensus definition requiring 103 organisms per ml to diagnose cystitis and 104 per ml for pyelonephritis.[3]
Clinical setting
Asymptomatic bacteriuria 無症狀菌尿症
This is especially common in women as evidenced by a minimum prevalence of 2-4% in young and 10% in elderly women. The cumulative prevalence of asymptomatic bacteriuria in women increases about 1% per decade throughout life regardless of ethnicity and geographic locations.
In contrast to women, the occurrence of asymptomatic bacteriuria in men is rare until after 55 years of age, at which time the prevalence increases per decade and approaches the rate in elderly women. Prostatic hypertrophy and increased likelihood of instrumentation account for the bacteriuria in older men.[11]
Differences between men and women in the rates of bacteriuria have been attributed to the shorter female urethra and its proximity to the vagina and rectal mucosa and their abundant microbial flora.
Clinical Features
Acute urethral syndrome
The cardinal symptoms of frequency and dysuria occur in more than 90% of ambulatory patients with acute genitourinary tract infections. However, one-third to one- half of all these patients do not have significant bacteriuria, although most have pyuria. These patients have acute urethral syndrome which can mimic both bladder and renal infections. Vaginitis, urethritis and prostatitis are common causes of the acute urethral syndrome.[14]
Vaginitis
The presence of an abnormal vaginal discharge (leucorrhoea) and irritation makes vaginitis the likely cause of dysuria unless a concomitant UTI can be confirmed by culture. Candida albicans, the most common specific cause of vaginitis, can be demonstrated by culture or by finding yeast cells in a gram-stained smear of vaginal secretions or in a saline preparation with the addition of potassium hydroxide.
Trichomoniasis can be documented with a saline preparation that shows the motile protozoa of trichomonas vaginitis. Generally, nonspecific vaginitis is associated with gardenerella vaginitis. A clue of this diagnosis is the presence of many small Gram-negative bacilli that adhere to vaginal epithelial cells.
Urethritis
Acute urinary frequency, dysuria and pyuria in the absence of vaginal symptoms favor the diagnosis of urethritis or UTI. Chlamydia trachomatis is the common cause of the acute urethral syndrome in women and of nonspecific urethritis in men. Neisseria gonorrhoeae is an important cause of urethritis and dysuria. Herpes simplex virus, usually type 2, is another sexually transmitted agent that can cause severe dysuria through ulceration in close proximity to the urethral orifice. The diagnosis of Herpes progenitalis can be confirmed by finding giant multinucleated transformed cells in epidermal scrapings stained with Wright's stain (Tzanck Smear), by isolating the virus in tissue cultures or by direct fluorescent antibody test.
Prostatitis
Prostatitis is a common problem in men that causes dysuria and urinary frequency in middle-aged and younger men more frequently than urinary tract infection do. Prostate syndromes have classically been divided into four clinical entities
Acute bacterial prostatitis
Chronic bacterial prostatitis
Nonbacterial prostatitis
Prostatodynia
Recently, consensus classification of prostatitis syndromes has come up. This classification includes four categories and two subcategories.[15]
Acute bacterial prostatitis;
Chronic bacterial prostatitis;
Chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS);
Asymptomatic inflammatory prostatitis.
CP/CPPS has been divided in to two sub-categories:
Inflammatory CP/CPPS; and
Non- inflammatory CP/CPPS
Acute bacterial prostatitis: The patient often appears acutely ill with the sudden onset of chills and fever, urinary frequency and urgency, dysuria, perineal and low back pain and constitutional symptoms. Rectal examination should be avoided because of the risk of precipitating sepsis, but may disclose a tender, hot and swollen prostate. Microscopic examination of the urine usually displays numerous white cells. Urine culture is usually positive for enteric Gram-negative bacteria and Gram-positive bacteria staphylococci and enterococci are less frequently isolated.
Chronic bacterial prostatitis: Relapsing UTIs is a hallmark of chronic bacterial prostatitis. Urinary frequency, dysuria, nocturia and low back and perineal pain are the usual symptoms, although patients may have a minimum of symptoms between UTIs. The patient is often afebrile, does not appear acutely ill, and may have an unremarkable prostate examination. Initially, there is a negative midstream urine examination and culture but after prostate massage, the urine is positive for white blood cells and culture grows a uropathogen.
Nonbacterial prostatitis: This is the most common form of chronic prostatitis. It mimics chronic bacterial prostatitis clinically and displays inflammatory cells on post-prostate massage specimens. However, a bacteriological culture of urine and prostatic secretions are sterile. The etiology is unknown, but some evidence exists for an infectious cause involving organisms that are difficult to culture.
Prostatodynia: This has also been referred to as chronic noninflammatory prostatitis. Clinically, it presents with symptoms similar to other forms of chronic prostatitis. It is distinguished by the absence of inflammatory cells or uropathogens from all specimens.
Chronic prostatitis/chronic pelvic pain syndrome: The traditional classification suggested that the prostate was the cause for some patients (nonbacterial prostatitis), whereas other problems were responsible in others (prostatodynia). The characteristic symptoms for either group were very poorly defined. CP/ CPPS acknowledges the central role of pain complaints in the syndrome. Also there is inherent recognition that the prostate gland may not be responsible for every patient's symptoms. Its two subcategories are as follows:
Inflammatory CP/CPPS: The consensus classification considers symptomatic patients without bacteriuria but who have inflammation in their expressed prostate secretions, their voided bladder 3 (VB3) or their semen fluid analysis (SFA), to have inflammatory CP/CPPS.
Noninflammatory CP/CPPS: Patients without inflammation in their expressed prostate secretions, their voided bladder 3 (VB3) or their semen fluid analysis (SFA) are considered to have noninflammatory CP/CPPS.
Asymptomatic inflammatory prostatitis: The consensus classification also includes a category for patients with objective evidence of prostatic inflammation noted during histological evaluation of prostatic tissue. This diagnosis commonly occurs in patients who have inflammation documented during evaluation of other urologic conditions, for example, prostatic evaluated for a raised prostate-specific antigen. Another example is seminal fluid inflammation noted during evaluation from an infertile couple. The long-term consequences of such asymptomatic inflammation are unknown. Further, only limited data are available on the relative merits of antimicrobial or other therapies for such asymptomatic patients.
Urinary tract infection: Despite the mimicking syndromes, a presumptive diagnosis of infections of urinary tract can be established economically by analyzing urine in patients with characteristic signs and symptoms. Acute uncomplicated UTIs mainly occur in women of child-bearing age. The presenting features are only suggestive of the site of infection. Patients with bacterial cystourethritis, as distinct from urethritis caused by sexually transmitted disease (STD) pathogens, will have prior episodes and experienced symptoms for less than one week and will experience suprapubic pain
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