Incidence of infectious complications following transrectal ultrasound-guided prostate biopsy in Calgary, Alberta, Canada: A retrospective population-based analysis

Development of an effective predictive screening tool for prostate cancer using the ClarityDX machine learning platform

The current prostate cancer (PCa) screen test, prostate-specific antigen (PSA), has a high sensitivity for PCa but low specificity for high-risk, clinically significant PCa (csPCa), resulting in overdiagnosis and overtreatment of non-csPCa. Early identification of csPCa while avoiding unnecessary biopsies in men with non-csPCa is challenging. We built an optimized machine learning platform (ClarityDX) and showed its utility in generating models predicting csPCa. Integrating the ClarityDX platform with blood-based biomarkers for clinically significant PCa and clinical biomarker data from a 3448-patient cohort, we developed a test to stratify patients' risk of csPCa; called ClarityDX Prostate. When predicting high risk cancer in the validation cohort, ClarityDX Prostate showed 95% sensitivity, 35% specificity, 54% positive predictive value, and 91% negative predictive value, at a ≥ 25% threshold. Using ClarityDX Prostate at this threshold could avoid up to 35% of unnecessary prostate biopsies. ClarityDX Prostate showed higher accuracy for predicting the risk of csPCa than PSA alone and the tested model-based risk calculators. Using this test as a reflex test in men with elevated PSA levels may help patients and their healthcare providers decide if a prostate biopsy is necessary.

Ciprofloxacin Alone vs. Ciprofloxacin plus an Aminoglycoside for the Prevention of Infectious Complications following a Transrectal Ultrasound-Guided Prostate Biopsy: A Retrospective Cohort Study

The purpose of this study was to evaluate the impact of augmented prophylaxis (ciprofloxacin augmented with an aminoglycoside) compared with that of empirical prophylaxis (ciprofloxacin alone) on transrectal post-prostate biopsy infectious complication (PBIC) rates. A retrospective cohort study evaluated 2835 patients receiving either augmented or empirical prophylactic regimen before undergoing a transrectal ultrasound-guided prostate biopsy between January 2010 and October 2018. The patients were compared according to prophylactic regimen received. The incidence of PBICs and the impact of risk factors were evaluated. A total of 1849 patients received the empirical regimen, and 986 patients received the augmented regimen. The composite PBIC rate was 2.1% (n = 39) and 0.9% (n = 9) (p = 0.019), respectively, and the SIRS rate was 1.9% and 0.8% (p = 0.020), respectively. Of the 50 patients presenting with a PBIC, 29 (58%) had positive cultures (blood and/or urine) for Escherichia coli, of which 28 (97%) were ciprofloxacin-resistant. Taking a fluoroquinolone in the previous 6 months and having a previous urinary tract infection within 1 year prior to the biopsy had significant impact on PBIC rates (p = 0.009 and p = 0.011, respectively). Compared with ciprofloxacin alone, augmented prophylaxis was associated with significantly lower PBICs.

MRI-based nomogram for the prediction of prostate cancer diagnosis: A multi-centre validated patient–physician decision tool

Objective:

To update and externally validate a magnetic resonance imaging (MRI)-based nomogram for predicting prostate biopsy outcomes with a multi-centre cohort.

Materials and methods:

Prospective data from five UK-based centres were analysed. All men were biopsy naïve. Those with missing data, no MRI, or prostate-specific antigen (PSA) > 30 ng/mL were excluded. Logistic regression analysis was used to confirm predictors of prostate cancer outcomes including MRI-PIRADS (Prostate Imaging Reporting and Data System) score, PSA density, and age. Clinically significant disease was defined as International Society of Urological Pathology (ISUP) Grade Group ⩾ 2 (Gleason grade ⩾ 7). Biopsy strategy included transrectal and transperineal approaches. Nomograms were produced using logistic regression analysis results.

Results:

A total of 506 men were included in the analysis with median age 66 (interquartile range (IQR) = 60–69). Median PSA was 6.6 ng/mL (IQR = 4.72–9.26). PIRADS ⩾ 3 was reported in 387 (76.4%). Grade Group ⩾ 2 detection was 227 (44.9%) and 318 (62.8%) for any cancer. Performance of the MRI-based nomogram was an area under curve (AUC) of 0.84 (95% confidence interval (CI) = 0.81–0.88) for Grade Group ⩾ 2% and 0.85 (95% CI = 0.82–0.88) for any prostate cancer.

Conclusion:

We present external validation of a novel MRI-based nomogram in a multi-centre UK-based cohort, showing good discrimination in identifying men at high risk of having clinically significant disease. These findings support this risk calculator use in the prostate biopsy decision-making process.

Level of evidence:

2c

The molecular mechanisms of fluoroquinolone resistance found in rectal swab isolates of Enterobacterales from men undergoing a transrectal prostate biopsy: the rationale for targeted prophylaxis

Background

Transrectal ultrasound-guided prostate biopsy (TRUS-Bx) is considered an essential urological procedure for the histological diagnosis of prostate cancer. It is, however, considered a “contaminated” procedure which may lead to infectious complications. Recent studies suggest a significant share of fluoroquinolone-resistant rectal flora in post-biopsy infections.

Methods

The molecular mechanisms of fluoroquinolone resistance, including PMQR (plasmid-mediated quinolone resistance) as well as mutation in the QRDRs (quinolone-resistance determining regions) of gyrA, gyrB, parC and parE, among Enterobacterales isolated from 32 of 48 men undergoing a prostate biopsy between November 2015 and April 2016 were investigated. Before the TRUS-Bx procedure, all the patients received an oral antibiotic containing fluoroquinolones.

Results

In total, 41 Enterobacterales isolates were obtained from rectal swabs. The MIC of ciprofloxacin and the presence of common PMQR determinants were investigated in all the isolates. Nine (21.9%) isolates carried PMQR with qnrS as the only PMQR agent detected. DNA sequencing of the QRDRs in 18 Enterobacterales (E. coli n = 17 and E. cloacae n = 1) isolates with ciprofloxacin MIC ≥ 0.25 mg/l were performed. Substitutions in the following codons were found: GyrA—83 [Ser → Leu, Phe] and 87 [Asp → Asn]; GyrB codon—605 [Met → Leu], ParC codons—80 [Ser → Ile, Arg] and 84 [Glu → Gly, Met, Val, Lys], ParE codons—458 [Ser → Ala], 461 [Glu → Ala] and 512 [Ala → Thr]. Six isolates with ciprofloxacin MIC ≥ 2 mg/l had at least one mutation in GyrA together with qnrS.

Conclusions

This study provides information on the common presence of PMQRs among Enterobacterales isolates with ciprofloxacin MIC ≥ 0.25 mg/l, obtained from men undergoing TRUS-Bx. This fact may partially explain why some men develop post-TRUS-Bx infections despite ciprofloxacin prophylaxis.

Antibiotic prophylaxis for transrectal ultrasound-guided prostatic biopsies: a comparison of two regimens

Background

There were controversies about the appropriate antibiotic prophylaxis regimen in order to decrease the incidence of post-transrectal ultrasound-guided prostatic biopsies (TRUS-PB) infectious complications. This study was conducted to compare the efficacy of two antibiotics prophylaxis regimens for TRUS-PB. In group 1, patients received single IV dose of 1 g amikacin 30 min before the procedure followed by oral ciprofloxacin 500 mg immediately after TRUS-PB. Group 2 patients received the same antibiotics, but ciprofloxacin started 1 day prior to TRUS-PB. Then ciprofloxacin was given twice daily for a total of 5 days in both groups.

Results

The study included 146 patients (54 in group 1 and 92 in group 2). The baseline characters (age, comorbidities, ASA score, PSA, prostate size and presence of urethral catheter) were comparable for both groups. Post-biopsy sepsis was observed in three patients (5.6%) in group 1 and one patient in group 2 (1.1%, P = 0.143). Sepsis was successfully managed in three, while one patient (1.9%) from group 1 required ICU admission for management of septic shock.

Conclusions

The incidence of sepsis after TRUS-PB is low when dual antibiotic prophylaxis (ciprofloxacin and amikacin) was used. Starting ciprofloxacin 1 day before TRUS-PB decreased the incidence of sepsis as well as its severity.

Phenotypic screening for quinolone resistance in Escherichia coli

Recent studies show that rectal colonization with low-level ciprofloxacin-resistant Escherichia coli (ciprofloxacin minimal inhibitory concentration (MIC) above the epidemiological cutoff point, but below the clinical breakpoint for resistance), i.e., in the range > 0.06-0.5 mg/L is an independent risk factor for febrile urinary tract infection after transrectal ultrasound-guided biopsy (TRUS-B) of the prostate, adding to the other risk posed by established ciprofloxacin resistance in E. coli (MIC > 0.5 mg/L) as currently defined. We aimed to identify the quinolone that by disk diffusion best discriminates phenotypic wild-type isolates (ciprofloxacin MIC ≤ 0.06 mg/L) of E. coli from isolates with acquired resistance, and to determine the resistance genotype of each isolate. The susceptibility of 108 E. coli isolates was evaluated by ciprofloxacin, levofloxacin, moxifloxacin, nalidixic acid, and pefloxacin disk diffusion and correlated to ciprofloxacin MIC (broth microdilution) using EUCAST methodology. Genotypic resistance was identified by PCR and DNA sequencing. The specificity was 100% for all quinolone disks. Sensitivity varied substantially, as follows: ciprofloxacin 59%, levofloxacin 46%, moxifloxacin 59%, nalidixic acid 97%, and pefloxacin 97%. We suggest that in situations where low-level quinolone resistance might be of importance, such as when screening for quinolone resistance in fecal samples pre-TRUS-B, a pefloxacin (S ≥ 24 mm) or nalidixic acid (S ≥ 19 mm) disk, or a combination of the two, should be used. In a setting where plasmid-mediated resistance is prevalent, pefloxacin might perform better than nalidixic acid.

Circulating blood miRNAs for prostate cancer risk stratification: miRroring the underlying tumor biology with liquid biopsies

Current risk stratification methods for prostate cancer – although they have seen marked improvements over the past decades – are far from perfect. Despite the significant utility of prostate-specific antigen as a biomarker to monitor for disease recurrence, it cannot predict which tumors will recur or recommend the best treatment for patients. Similarly, although biopsies are imperative for diagnosis and staging, they are saddled with limitations and risks. We must move toward a noninvasive biomarker that has predictive and prognostic efficacy. We therefore review the current literature on circulating miRNA biomarkers, apply their use to two significant clinical problems (ie, how limitations of prostate biopsies can impact diagnosis and treatment management, and the need to tailor treatment for a clinically heterogeneous disease), and evaluate how circulating miRNAs have inherent properties that make them ideal liquid biomarkers. We also outline current gaps in knowledge that must be addressed before they can be implemented into routine clinical practice. With further research on their function and validation of their biomarker utility in large prospective cohorts, circulating miRNAs will likely prove to be the liquid biopsies of tomorrow.

A significant percentage of patients with transrectal biopsy-related infections have positive blood cultures but negative urine cultures. A literature review and meta-analysis

BACKGROUND

Infectious complications after transrectal prostate biopsy are rare. Nevertheless, since these are frequent procedures, the burden of infectious complications is high. Considering the increasing antimicrobial resistance, microbiological confirmation is important to guide antimicrobial therapy.

METHODS

We reviewed PubMed for original studies providing concurrent urine and blood culture data in symptomatic patients with transrectal biopsy-related infectious complications. We performed a proportions meta-analysis (with MedCalc) and calculated the pooled yield of urine and blood cultures and the pooled discordance rate between urine and blood cultures.

RESULTS

Our review identified 41 studies, involving 852 patients with infectious complications after transrectal prostate biopsy and sufficient data to calculate discordance. The pooled yield of urine cultures was 64.6% (95% CI: 56.2-72.3%, I² 83%), the pooled yield of blood cultures was 43% (95% CI: 36.5-49.7%, I² 74%) and the pooled discordance rate was 14% (95% CI: 10.6-17.8%, I² 53%). In subgroup analyses the pooled discordance was; 19.6% (95% CI: 11.8-28.9%, I² 31%) in 113 patients presenting within 2 calendar days after the biopsy and 11.2% (95% CI: 4.5-20%, I² 47%) in 143 patients presenting with fever and symptoms of lower urinary tract symptoms. The statistical and methodological heterogeneity of included studies was high.

CONCLUSION

Obtaining blood cultures is reasonable in all patients presenting with systemic symptoms suggestive of infection after a transrectal prostate biopsy. Blood cultures can provide additional microbiological data in about 1 of 7 patients with post-biopsy infectious complications. Prospective studies are needed to validate these results.

Rectal E. coli above ciprofloxacin ECOFF associate with infectious complications following prostate biopsy

Transrectal prostate biopsies carry the risk of infection. By using non-selective culture plates, instead of commonly used ciprofloxacin (CIP)-containing plates, we analyzed the association between Escherichia coli CIP minimal inhibitory concentration (MIC) and post-biopsy infectious complications. A pre-biopsy rectal swab was taken from 207 consecutive men, scheduled for transrectal 12-core prostate biopsy with CIP 750 mg as the mostly used prophylaxis. CIP MIC of rectal Gram-negative bacilli was determined from a chromogenic agar. Rectal E. coli were categorized to resistant (R) and intermediate (I) isolates together (R + I, MIC > 0.25 mg/l) and to sensitive (S, MIC ≤ 0.25 mg/l) using EUCAST clinical breakpoints. In addition, epidemiological cutoff (ECOFF R, MIC > 0.064 mg/l) was used for categorization. Eighteen (8.7%) men showed CIP R + I E. coli by the EUCAST breakpoints and 41 (19.8%) using the ECOFF R criteria. During follow-up, 15 (7.2%) men had infectious symptoms, of which 9 (4.3%) were culture-confirmed infections. Only 4 (26.7%) of these 15 patients showed R + I E. coli in the rectal swab according to EUCAST, but 10 (66.7%) using the ECOFF cutoff. Rectal E. coli CIP R + I by the EUCAST clinical breakpoints associated with infectious complications with OR 5.7 (95% CI 1.5-21.8, P = 0.005) and ECOFF R E. coli by OR 10.7 (95% CI 3.0-37.6, P < 0.001). Men carrying rectal E. coli with moderately lowered CIP susceptibility (MIC > ECOFF 0.064 mg/l) were identified and, interestingly, they showed a high risk of developing infectious symptoms after the biopsy. This explains why some men develop infectious complications despite appropriate antibiotics before prostatic biopsies.

TRIAL REGISTRATION

NCT02140502.

Spondylodiscitis with Epidural and Psoas Muscle Abscesses as Complications After Transrectal Ultrasound-guided Prostate Biopsy: Report of a Rare Case

A 71-year-old man presented with spondylodiscitis with epidural and psoas muscle abscesses following transrectal ultrasound (TRUS)-guided prostate biopsy. These rare complications were detected by computed tomography of the abdomen and magnetic resonance imaging of the lumbar spine. The patient was successfully treated with antibiotics and underwent neurosurgery. Awareness of presentations such as backache and weakness of the lower limbs after prostate biopsy is important as these symptoms are usually mistaken for bone or muscle problems and often not recognized as being related to infection.

Integration of free-hand 3D ultrasound and mobile C-arm cone-beam CT: Feasibility and characterization for real-time guidance of needle insertion

This work presents development of an integrated ultrasound (US)-cone-beam CT (CBCT) system for image-guided needle interventions, combining a low-cost ultrasound system (Interson VC 7.5MHz, Pleasanton, CA) with a mobile C-arm for fluoroscopy and CBCT via use of a surgical tracker. Imaging performance of the ultrasound system was characterized in terms of depth-dependent contrast-to-noise ratio (CNR) and spatial resolution. US-CBCT system was evaluated in phantom studies simulating three needle-based procedures: drug delivery, tumor ablation, and lumbar puncture. Low-cost ultrasound provided flexibility but exhibited modest CNR and spatial resolution that is likely limited to fairly superficial applications within a ∼10cm depth of view. Needle tip localization demonstrated target registration error 2.1-3.0mm using fiducial-based registration.

Increase of prostate biopsy-related bacteremic complications in southern Finland, 2005-2013: a population-based analysis

BACKGROUND

The most severe manifestations of prostate biopsy complications are bacteremic infections. These complications are increasing alarmingly.

METHODS

A retrospective cohort study of 17 183 transrectal prostate biopsies performed at the Helsinki and Uusimaa hospital district in southern Finland during 2005-2013. Biopsies were linked to a database of positive blood cultures, yielding 111 bacteremic cases, and yearly bacteremia rates were determined. By multiple regression analysis, demographic risk factors of the whole biopsy cohort for developing bacteremia or fluoroquinolone (FQ)-resistant bacteremia were studied. Clinical risk factors for bacteremia caused by an FQ-resistant organism and for serious bacteremic outcomes were studied by univariate and multivariate analyzes.

RESULTS

The average bacteremia rate was 0.7% (111 of 17 183 biopsies) and an increase was observed from 0.5% in 2005 (95% confidence interval (CI): 0.3-0.9) to 1.2% in 2012 (95% CI 0.8-1.8); 53.2% were caused by an FQ-resistant organism. In univariate regression analysis, previous biopsy sessions and increasing calendar year of biopsy associated with the risk of developing bacteremia (odds ratio (OR) 1.232, 95% CI: 1.020-1.488, P=0.030 and OR 1.164, 95% CI: 1.079-1.255, P<0.001, respectively), but only increasing calendar year of biopsy remained statistically significant (OR 1.155, 95% CI: 1.070-1.247, P<0.001) in multivariate analysis. Foreign travel within 3 months was associated with FQ resistance in multivariate analysis (OR 7.158, 95% CI: 1.042 to infinite, P=0.045). The study failed to show any significant clinical risk factors for serious bacteremic outcomes (requiring intensive care, developing deep infection foci or death).

CONCLUSIONS

The postbiopsy bacteremia rate doubled during the study period and half of the cases were caused by FQ-resistant organisms. Recent foreign travel increased the risk for FQ resistance. Future research efforts should be aimed at better identifying risk factors, targeted prophylaxis and reducing the need for biopsies.

Malakoplakia of the prostate masquerading as locally advanced prostate cancer on mpMRI

A 66-year-old man was referred for urological evaluation for an abnormal digital rectal exam (cT2a, subtle nodule at left base, 121 cc prostate) and an elevated prostate specific antigen (PSA) of 8.0 ng/ml. Subsequent 12-core transrectal ultrasound (TRUS)-guided biopsy revealed Gleason 3+4 adenocarcinoma in seven of 12 cores, including all six cores on the right side and one core at the left apex. No extraprostatic extension was identified. Post-biopsy, the patient developed urinary retention requiring a catheter, as well as an Escherichia coli (E. coli) urinary tract infection (UTI) requiring hospitalization and intravenous antibiotics.

Extraintestinal Pathogenic Escherichia coli, a Common Human Pathogen: Challenges for Vaccine Development and Progress in the Field

Extraintestinal pathogenic Escherichia coli (ExPEC) is the most common gram-negative bacterial pathogen in humans. ExPEC causes the vast majority of urinary tract infections (UTIs), is a leading cause of adult bacteremia, and is the second most common cause of neonatal meningitis. Increasing multidrug resistance among ExPEC strains constitutes a major obstacle to treatment and is implicated in increasing numbers of hospitalizations and deaths and increasing healthcare costs associated with ExPEC infections. An effective vaccine against ExPEC infection is urgently needed. The O antigen, a component of the surface lipopolysaccharide, has been identified as a promising vaccine target. With the availability of a novel bioconjugation technology it is expected that multivalent O antigen conjugate vaccines can be produced at industrial scale. Clinical proof of concept of a 4-valent O antigen conjugate vaccine is ongoing. An ExPEC vaccine effective against strains that are associated with major diseases and resistant to multiple drugs could be routinely delivered to individuals at risk of developing severe E. coli infection, such as elderly people, individuals undergoing abdominal surgery and prostatic biopsy procedures, and persons at risk of recurrent and/or complicated UTI.

Rapid increase in multidrug-resistant enteric bacilli blood stream infection after prostate biopsy - A 10-year population-based cohort study

BACKGROUND

Bloodstream infection following a transrectal prostate biopsy is a well-known and feared complication. Previous studies have shown an increase in multi-resistant bacterial infections as a consequence of higher usage of antibiotics in investigated populations. Our aim was to analyze bacterial resistance patterns in positive blood cultures, after prostate biopsies in Stockholm, Sweden, where the use of antibiotics has been low and decreasing during the last 10 years.

METHODS

From the three pathology laboratories in Stockholm, reports of prostate examinations were retrieved (n = 56,076) from 2003 to 2012. By linking men to the National Patient Register all but prostate core biopsies were excluded (n = 12,024). Prostate biopsies in men younger than 30 years of age were excluded (n = 5) leaving 44,047 biopsies for analysis. From laboratory information systems data regarding blood cultures were retrieved. Proportions of blood cultures within 30 days by year were calculated. Crude and adjusted logistic regression models were used to estimate ORs.

RESULTS

In total, 44,047 prostate biopsies were performed in 32,916 men over 10 years. On 620 occasions a blood culture was drawn within 30 days of the biopsy; 266 of these were positive. The proportions with positive blood cultures in 2003 and 2012 were 0.38 and 1.14%, respectively. The proportion of multidrug-resistant bacteria increased significantly during the study. In the crude and the adjusted analysis, the year of biopsy and Charlson Comorbidity Index were associated with the risk of having a positive blood culture.

CONCLUSION

Multidrug-resistant enteric bacilli are becoming a problem in Sweden, despite low antimicrobial use. Men need to be informed about the increasing risks of infectious complications of transrectal prostate biopsy. One out of 50 men undergoing a prostate biopsy will develop symptoms suggestive of a bloodstream infection after the biopsy and one in 100 men will have a positive blood culture.

Complications of transrectal ultrasound-guided prostate biopsy: impact of prebiopsy enema

Purpose

Transrectal ultrasound (TRUS)-guided biopsy of the prostate is usually safe. However, some patients are hospitalized owing to complications from TRUS biopsy. We identified the risk factors for complications and effective preventive measures for treating complications after TRUS biopsy.

Materials and Methods

Medical records and radiological images of 1,083 patients who underwent TRUS biopsy of the prostate over 10 years in Gyeongsang National University Hospital were examined retrospectively to investigate the correlation between complications after TRUS biopsy and preventive antibiotics, prebiopsy enema, number of biopsy cores, and pathological findings.

Results

Complications occurred in 69 patients (6.4%). The complication rates of the 1,008 patients who received antibiotics and the 75 patients who did not were 6.3% and 8.0%, respectively (p=0.469). Complication rates of the pre-biopsy enema group (n=658) and the group without prebiopsy enema (n=425) were 4.7% and 8.9%, respectively (p=0.007). Complication rates of the 6-core biopsy group (n=41) and the 12-core biopsy group (n=955) were 7.3% and 6.3%, respectively (p=0.891). Complication rates of the prostate cancer group (n=306) and the no prostate cancer group (n=713) were 6.2% and 6.6%, respectively (p=0.740).

Conclusions

A prebiopsy enema was associated with a reduced risk of complications after TRUS biopsy. Preventive antibiotics, number of biopsy cores, and pathological findings did not significantly influence the complication rate.