Antibody-coated Bacteria Test Research Articles

Markers of ventilator-associated pneumonia

The diagnosis of ventilator-associated pneumonia (VAP) is difficult for several reasons. Firstly, clinical markers show a large percentage of false-positive and false-negative results. Secondly, microbiological diagnosis based on quantitative cultures of protected specimen brush (PSB), bronchoalveolar lavage (BAL), and endotracheal aspirates also present false-positive and false-negative results. Furthermore, definite results are delayed for 48-72 hours. For all these reasons it would be an advantage to have a biological marker of ventilator-associated pneumonia in clinical practice. Since clinical features of pneumonia in mechanically ventilated patients are neither specific nor sensitive, rapid markers of pneumonia might be of great assistance to the clinician in deciding whether to start an empiric antibiotic regimen. A marker of ventilator-associated pneumonia could be a rapid alternative diagnostic method which permits the definite diagnosis of pneumonia. Accordingly, specific markers of VAP, namely the presence of intracellular microorganisms, the detection of elastin fibres, the antibody-coated bacteria test, the level of endotoxin in bronchoalveolar lavage fluid, the local production of interleukin-8, the levels of lactate dehydrogenase, and decreased surfactant protein A, may be important as they can provide a rapid diagnosis of VAP. Among the markers alluded to above, the search for intracellular bacteria in polymorphonuclear leukocytes or macrophages is the most widely validated technique with an excellent specificity, provided that prior antibiotics are not given. However, this technique has its own limitations; it requires a considerable time effort for the microbiologist, and also compels the performance of BAL, a technique not always harmless to the patient.

Markers of ventilator-associated pneumonia

The diagnosis of ventilator-associated pneumonia (VAP) is difficult for several reasons. Firstly, clinical markers show a large percentage of false-positive and false-negative results. Secondly, microbiological diagnosis based on quantitative cultures of protected specimen brush (PSB), bronchoalveolar lavage (BAL), and endotracheal aspirates also present false-positive and false-negative results. Furthermore, definite results are delayed for 48-72 hours. For all these reasons it would be an advantage to have a biological marker of ventilator-associated pneumonia in clinical practice. Since clinical features of pneumonia in mechanically ventilated patients are neither specific nor sensitive, rapid markers of pneumonia might be of great assistance to the clinician in deciding whether to start an empiric antibiotic regimen. A marker of ventilator-associated pneumonia could be a rapid alternative diagnostic method which permits the definite diagnosis of pneumonia. Accordingly, specific markers of VAP, namely the presence of intracellular microorganisms, the detection of elastin fibres, the antibody-coated bacteria test, the level of endotoxin in bronchoalveolar lavage fluid, the local production of interleukin-8, the levels of lactate dehydrogenase, and decreased surfactant protein A, may be important as they can provide a rapid diagnosis of VAP. Among the markers alluded to above, the search for intracellular bacteria in polymorphonuclear leukocytes or macrophages is the most widely validated technique with an excellent specificity, provided that prior antibiotics are not given. However, this technique has its own limitations; it requires a considerable time effort for the microbiologist, and also compels the performance of BAL, a technique not always harmless to the patient.

Urinary tract infection in men — An internist's viewpoint

Urinary tract infection (UTI) in men relates to a combination of factors: 1) the presence of minimal to moderate obstruction which leads to impaired voiding and 2) the invasive ability of virulent strains of Escherichia coli. This was best illustrated in the study" of male urinary tract infection in the Veterans Administration cooperative study [1]. The study was developed to determine the duration of therapy necessary to achieve a reasonable cure rate for those men with significant urinary tract infection. However, in-depth studies of the patients and organisms indicated that they had mild obstruction of the urinary tract and urovirulent E. coli. Localization tests showed that all men had upper tract infection, but only one-half had prostate infection. It was also found that longer therapy for 12 weeks with co-trimoxazole was required for a greater than 50% cure rate compared to a cure rate of 20% in those given a standard 10-day course of therapy. After screening many patients with bacteriuria, 46 were found to be qualified for the study in three Veterans Administration Medical Centers. Twenty-nine of these patients had medical disease and 13 had urinary tract complications, all of which were mild. A post-voiding cystogram demonstrated a slight to moderate residual in 14 patients. All patients had repeatedly positive antibody-coated bacteria tests but only one-half had infection of the prostate by a localization study [1]. Pyuria was demonstrated in 95%. Pyuria defined as greater than 10 nucleated leukocytes/HPF has been shown to be a predictor of the probability of urinary tract infection or, as old style urologists called it, "dirty urine" [2]. Seventy percent had E. coli, the rest a variety of other pathogens. Of the ones with E. coli, 0 antigen was present in three-quarters, K antigen in one-half, and particular urovirulent OK antigen types were found frequently. In subsequent studies, two-thirds of these strains were found to adhere to the kidney, half with mannose-resistant adherence and half with mannose-susceptible adherence, whereas isolates from persons with bladder infection failed to adhere [3]. Adherence to the kidney correlated with surface hydrophobicity of the strains [3]. Hence, the organisms associated with male urinary tract infections can be considered to have urovirulent characteristics 60-70% of the time which favour adherence to the kidney. The therapeutic efficacy of co-trimoxazole is seen in Table 1. Response to therapy was more successful in those who received 12 weeks of therapy, had no evidence of prostatic infection and no evidence of post-voiding residual. These findings were confirmed in another series which showed that 6 weeks of co-trimoxazole was more successful than 10 days of therapy in men with urinary tract infection [4]. Recurrent infection was frequent in men but was only symptomatic in 20% (compared to 57% who had Table 1 : Therapeutic efficacy of co-trirnoxazole.

Single dose treatment failure in women with acute cystitis.

Single dose treatment regimens (SDT) are effective, inexpensive alternatives to longer courses of therapy for adult females with acute cystitis or asymptomatic bacteriuria. A number of SDT regimens consistently cure 85 to 100% of women with acute cystitis and 50 to 80% of women with asymptomatic bacteriuria. However, SDT is inherently less effective than longer regimens because many upper tract infections are not cured. Initial SDT studies suggested that most patients with significant renal invasive disease or underlying urological abnormalities fail therapy. As a result, SDT has been proposed as an efficient strategy to diagnose significant upper tract infections with accompanying pathology that merit additional investigation or treatment. Few studies have refuted or supported this hypothesis. Single-dose treatment studies show an association between the site of infection as determined by the antibody-coated bacteria (ACB) test and treatment outcome. Patients with ACB-negative tests have a cure rate of over 90% in almost all studies in which the organism is susceptible to the agent chosen. Patients with positive ACB tests tend to have treatment failure rates of 30 to 50%. However, imaging studies have not been carried out in parallel with these studies and the validity of using single-dose treatment failure to screen women for significant upper tract pathology has still not been established.

Clinical significance of candiduria: An update

Although candiduria is not an infrequent finding, its clinical significance is uncertain. Herein the pertinent literature including ours on candiduria and related conditions are reviewed, with emphasis on methods of differentiating true urinary candidiasis from simple colonization, using colony counts in urine specimens, antibody-coated bacteria test, serologic diagnosis including serum antibody titer, Candida antigen and metabolite assays. The predisposing factors and treatment in relation to antifungal susceptibility tests are also presented.

Do antibody-coated bacteria prove bacterial prostatitis?

Using the immunofluorescence technique in 187 patients with bacteriologically proven prostatitis according to the Meares-Stamey test demonstrated a significant amount of antibody-coated bacteria (ACB) in their ejaculates. The ACB test was useful to discriminate between chronic bacterial prostatitis and prostatodynia with a sensitivity of 65% and a specifity of 92%; likewise the ACB test is superior to complement and coeruloplasmin estimation in the ejaculate by radial immunodiffusion usually recommended for the differential diagnosis of inflammatory and psychosomatic diseases of the prostate.

The Diagnostic Utility of the Antibody-Coated Bacteria Test in Intubated Patients

Pilot study to determine if the presence of antibody-coated bacteria (ACB) in sputum specimens obtained from endotracheal tube suctioning would aid in the diagnosis of lower respiratory tract infection (LRTI). All endotracheally intubated and mechanically ventilated patients for a two-month period were recruited for study. The diagnosis of LRTI was based on a clinical suspicion sufficient enough to start or change antibiotic therapy. Specimens were obtained by blind endotracheal tube suctioning. After processing, sputum smears were stained with fluorescein-labelled antibody to the Fc portion of IgG, IgM, and IgA. More than five fluorescein-labelled bacteria per oil immersion field were considered positive smears. Seventy-one specimens were obtained from 36 patients. Eighteen specimens were positive in 12 patients, all of whom had LRTI. No specimen was positive in patients not diagnosed as having LRTI. The ACB test was positive in 12 of 25 patients with LRTI. Patients with LRTI but negative ACB were more likely to have received prior antibiotic therapy (p less than 0.001). ACB was positive prior to the clinical diagnosis of LRTI in seven of nine patients (av 4.1 days, range 2-6 days) and converted to negative in three specimens obtained seven or more days after starting appropriate antibiotics, while in three specimens it remained positive three-six days post treatment initiation. The ACB test appears to be highly specific for the presence of LRTI in intubated patients. Sensitivity of the test may be adversely affected by prior antibiotic therapy. A positive ACB test may predict the subsequent development of LRTI. Further study is warranted.

Kinetics and Comparative Efficacy of Ofloxacin versus Co-Trimoxazole in the Asymptomatic Bacteriuria of Elderly Subjects

In a prospective randomized study ofloxacin (400 mg orally once daily) versus co-trimoxazole (320/1,600 mg orally once daily) were given for 3 weeks in 30 and 22 elderly semimobile patients respectively, suffering from asymptomatic bacteriuria. From the obtained results it was evident that: (a) ofloxacin was superior to co-trimoxazole regarding eradication of bacteriuria (p less than 0.05) particularly in patients with a positive antibody-coated bacteria test; (b) a high rate of superinfections and reinfections with strains resistant to co-trimoxazole was observed in both groups indicative of hidden underlying conditions predisposing to urinary tract infections and (c) ofloxacin did not accumulate in serum during prolonged therapy but the half-life ranged between 8.3 and 10.2 h.

Antibody coated bacteria in urine of patients with recent spinal injury.

Twenty patients with an acute spinal injury were prospectively studied to assess the clinical importance of antibody coated bacteria (ACB) in the urine and the association among the different bacterial species with a positive antibody coated bacteria test. Clinical urinary tract infection was associated with a positive ACB test on 45% of occasions. Three hundred and ninety nine urine samples containing 541 bacterial isolates were assessed for the presence of ACB; 13% were found to be positive and 87% negative for ACB; 67% of urines contained a single bacterial isolate. Pseudomonas aeruginosa was most commonly associated with clinical urinary tract infection, found in 25% of episodes, followed by Proteus mirabilis (17.5%), Klebsiella sp (12.5%), and Proteus morganii (10%). Providencia stuartii, however, was most commonly associated with a positive ACB test (found in 17%). Other bacteria associated with a positive ACB test included Klebsiella sp (14%), Acinetobacter sp (12.5%), Pseudomonas aeruginosa (12%), Citrobacter sp (11.5%). A positive ACB test is not to be expected from a patient with spinal injury who has a catheter in place, and the test may provide a useful guide to identify those patients with an invasive infection. It is doubtful that a decision to treat or not treat bacteriuria could rest on the identification of the bacterial species alone.

Clinical Significance of the Antibody‐coated Bacteria Test in Patients with Candiduria

The clinical significance of the antibody-coated bacteria (ACB) test was evaluated with urine from 20 patients with candiduria. The relationship between the in vitro antibody-coating test for Candida albicans, urinary immunoglobulin (Ig) levels and serum antibody titres was evaluated in 40 patients without candiduria, 23 of whom had bacterial urinary tract infection (UTI). Urine specimens from 19 of the 20 patients with candiduria gave a positive result regardless of clinical symptoms; 12/23 specimens of urine from patients with bacterial UTI were positive for antibody-coated C. albicans cells, but there were no positive samples in the patients without UTI. All of the coating-positive patients had serum antibody titres greater than or equal to 1:160, the class of antibody being dependent on the urinary Ig levels. The ACB test for candiduria is of little clinical value in indicating invasive Candida UTI as the Candida cells appear to adhere to antibodies in urine contaminated with circulating fluids.

Review of the Efficacy of Oral Norfloxacin in Pyelonephritis and Nosocomial Urinary Tract Infection

One hundred thirty-eight patients with pyelonephritis were treated with norfloxacin, 400 mg twice daily. Women accounted for 74% of cases, and Escherichia coli was the predominant pathogen, accounting for 51% of organisms. Tests for antibody-coated bacteria (ACB) were performed in 48% of patients, and 72% (48 of 67) were positive. Forty percent of the patients had temperatures greater than 37.6 degrees C at the time of study entry. Patients who had both fevers and positive ACB tests had cure rates similar to those of afebrile, ACB-negative patients. Norfloxacin was also highly effective in the treatment of multiply resistant, nosocomial urinary tract infections (UTIs), in which Pseudomonas aeruginosa and E. coli predominated. It is concluded that, when used appropriately, i.e., in nonbacteremic patients who are able to absorb oral drugs, norfloxacin is a highly effective alternative modality in the therapy of certain UTIs that historically have been treated with parenteral antibiotics.

Southwestern Internal Medicine Conference: Prognosis in Pyelonephritis: Promise or Progress?

Prognosis in pyelonephritis, or upper urinary tract infection, is provided. This infection is not responsible for progressive renal disease in young or elderly patients but accounts for frequent febrile episodes in women of all ages and men after the age of 50. Vigorous local immune response develops with the infection, which never succeeds in eradicating bacteria but does limit the infection and provides a diagnostic test: the antibody-coated bacteria test. Emphasis is placed on the need for a localization test for upper tract infection because studies based exclusively on clinical criteria are invalid. Appropriate therapy for mildly ill patients is given with recommendations of combination therapy for severely ill persons. Long-term follow-up is critical because most patients with recurrent infections can be given preventive therapy without subjecting them to needless urologic evaluation.

Localization of Urinary Tract Infection in Elderly, Institutionalized Women With Asymptomatic Bacteriuria

We determined the site of urinary tract infection in 51 elderly, institutionalized women (mean age, 80.5 years) with asymptomatic bacteriuria by using the Fairley bladder washout technique. Thirty-four (67%) infections were localized in the kidney and 17 (33%) in the bladder. Women with renal infection were older than those with bladder infection (81.9 vs. 77.6 years of age; P = .04). The antibody-coated bacteria test had a sensitivity of 58%, specificity of 71%, positive predictive value of 82%, and negative predictive value of 43% for upper-urinary-tract infection. A quantitative urinary leukocyte count of greater than or equal to 20 leukocytes/mm3 had a positive predictive value of 80% and a negative predictive value of 88% for upper-urinary-tract infection. This study suggests that the majority of elderly, institutionalized women with asymptomatic bacteriuria have upper-urinary-tract infection. Both the antibody-coated bacteria test and the quantitative urinary leukocyte count may be useful as noninvasive tests for localization of urinary tract infection in this population.

Localization of urinary tract infection in elderly, institutionalized women with asymptomatic bacteriuria.

We determined the site of urinary tract infection in 51 elderly, institutionalized women (mean age, 80.5 years) with asymptomatic bacteriuria by using the Fairley bladder washout technique. Thirty-four (67%) infections were localized in the kidney and 17 (33%) in the bladder. Women with renal infection were older than those with bladder infection (81.9 vs. 77.6 years of age; P = .04). The antibody-coated bacteria test had a sensitivity of 58%, specificity of 71%, positive predictive value of 82%, and negative predictive value of 43% for upper-urinary-tract infection. A quantitative urinary leukocyte count of greater than or equal to 20 leukocytes/mm3 had a positive predictive value of 80% and a negative predictive value of 88% for upper-urinary-tract infection. This study suggests that the majority of elderly, institutionalized women with asymptomatic bacteriuria have upper-urinary-tract infection. Both the antibody-coated bacteria test and the quantitative urinary leukocyte count may be useful as noninvasive tests for localization of urinary tract infection in this population.

Single-dose cephalexin therapy for acute bacterial urinary tract infections and acute urethral syndrome with bladder bacteriuria.

The efficacy of single-dose therapy with 3 g of cephalexin was evaluated in 129 women with symptoms of acute uncomplicated lower urinary tract infections. Of 91 patients with significant bacteriuria, 61 (67%) were cured of their original infection; this was similar to the 54 to 79% cure rates reported in unselected populations of women of a wide age range treated for acute uncomplicated urinary tract infections with a single dose of amoxicillin or trimethoprim-sulfamethoxazole (J. Rosenstock, L. P. Smith, M. Gurney, K. Lee, W. G. Weinberg, J. N. Longfield, W. B. Tauber, and W. W. Karney, Antimicrob. Agents Chemother. 27:652-654, 1985; N. E. Tolkoff-Rubin, M. E. Wilson, P. Zuromskis, I. Jacoby, A. R. Martin, and R. H. Rubin, Antimicrob. Agents Chemother. 25:626-629, 1984). The cure rates of (87%) for our younger patients, those less than 25 years of age, was better than that (46%) for our patients over 40 years of age (P less than 0.001). Patients with infections that were negative in an antibody-coated bacteria test were cured at a significantly higher rate than those with infections that were positive in an antibody-coated bacteria test (71 versus 19%; P = 0.003). Those patients with infections caused by cephalexin-susceptible organisms were cured at a rate similar to that for patients with infections caused by cephalexin-resistant organisms (68 versus 50%; P = 0.62). The cure rate for suburban patients was 90%, versus 45% for inner-city patients (P = 0.008). Of the 28 women with acute urethral syndrome due to low-level bacteriuria, 27 were cured.

Single-Dose Therapy for Cystitis in Women-Reply

In Reply.— We appreciate Dr Bailey's comments and agree that trimethoprim-sulfamethoxazole appears to be a more effective single-dose agent for treating acute bacterial cystitis than are penicillins and cephalosporins. A recent review of published studies found single-dose amoxicillin to be less effective (mean efficacy, 72%) than single-dose trimethoprim-sulfamethoxazole (mean efficacy, 90%). 1 However, the best single-dose treatment regimen(s) can be ascertained only through randomized comparative trials. The explanation for the apparent difference in efficacy of single-dose trimethoprim-sulfamethoxazole and amoxicillin is unclear. The prevalence of amoxicillin-resistant Escherichia coli strains exceeds that of trimethoprim-sulfamethoxazole-resistant strains in Seattle, and thus offers a partial explanation. However, many reported failures involve E coli susceptible to both drugs. It is likely, although unproved, that the lesser efficacy of the penicillins and cephalosporins relates to their more rapid elimination from the body. This interesting question deserves further investigation. Regarding the antibody-coated bacteria test, published data demonstrate a

Single-Dose Therapy for Cystitis in Women

We evaluated single-dose regimens of trimethoprim-sulfamethoxazole, amoxicillin, and cyclacillin as treatment for acute cystitis in 38 women. The trial was prematurely stopped because of frequent treatment failures. At two days after treatment, all 13 patients given trimethoprim-sulfamethoxazole were cured, while four (31%) of 13 given amoxicillin and four (33%) of 12 given cyclacillin had persistent bacteriuria. At two weeks, 11 (85%) of 13 patients given trimethoprim-sulfamethoxazole, six (50%) of 12 given amoxicillin, and three (30%) of ten given cyclacillin were cured. One patient with positive results of antibody-coated bacteria testing who was treated with cyclacillin had signs and symptoms of acute pyelonephritis three days after treatment, and two patients treated with amoxicillin and one treated with trimethoprim-sulfamethoxazole converted antibody-coated bacteria test results from negative to positive after therapy. We conclude that single-dose treatment of cystitis in unselected women with cyclacillin and amoxicillin may result in low cure rates and that progression to acute pyelonephritis may occur following ineffective single-dose therapy.

A modified bladder washout test to improve diagnostic results in chronic urinary tract infections.

Bladder washout (BWO) and antibody-coated bacteria (ACB) tests were performed on 25 patients with radiological and/or clinical evidence of chronic upper urinary tract infection (UTI) and 12 patients with asymptomatic bacteriuria. Using a traditional single-washout procedure, the BWO test gave equivocal results in many cases of chronic pyelonephritis; this seemed mainly due to the lack of complete bladder sterilization. A modified procedure, including double sterilization and irrigation, biochemical typing of isolated bacteria, and evaluation of temporal pattern of bacteriuria recurrence, was then introduced. Although preliminary results of the modified BWO test demonstrated a general improvement in the diagnosis of the infection site, it seemed rather difficult, at least in chronic UTI, to establish localizing criteria based on definite numeric changes in bacterial counts after washout.

Single-dose treatment with netilmicin for different clinical forms of urinary tract infections.

A group of 44 patients with various clinical forms of urinary tract infections received a single dose of 300 mg netilmicin i.m. The treatment was efficacious in all patients with infections which were negative in the antibody-coated bacteria test and not complicated by anatomic and/or functional abnormalities of the kidneys and urinary tract. After three weeks the recurrence rate was only 19%. Single-dose treatment also proved very effective against urinary tract infections in renal transplant patients whose infection is almost always located in the lower urinary tract. In contrast, the short-term results of treatment were much poorer in complicated infections and particularly in urinary tract infections which were positive in the anti-body-coated bacteria test; here, the recurrence rate was 67%.

Antibody coated bacteria in ejaculatein bacterial prostatitis

In patients with bacteriologically proved prostatitis (Stamey test) ejaculate was examinedfor antibody-coated bacteria (ACB). Forty-four of the 68 patients (65%) with bacteriologically proved prostatitis had ACB in the ejaculate, but only 7 of 89 patients (8%) with prostatodynia. Concomitantly, coeruloplasmin and complement (C3) concentrations in the ejaculate were examined by radial immunodiffusion (RID). The ACB test had much higher specificity (92%) than RID, and the sensitivity of ACB was 65 per cent.