Prophylactic single-dose of gentamicin and metronidazol in patients undergoing transrectal ultrasound-guided prostate biopsy: A prospective clinical study

Carolina D'Elia1, Emanuela Trenti1, Greta Spoladore1, Salvatore Mario Palermo1, Christian Ladurner1, Peter Mian1, Armin Pycha1
  • 1 Ospedale Generale di Bolzano (Bolzano)

Objective

Prostate biopsy, conducted with aim to detect prostate cancer, is not free from complications, with a post biopsy prostatitis rate ranging between 1 and 5% [1]; prostatitis is a frequent cause of hospitalization and can lead to urosepsis, a life threatening condition.
EAU Guidelines recommend antibiotic phrophylaxis with fluoroquinolones, that provide high bioavailability and excellent penetration into the prostate tissue, preferring to ciprofloxacin ofloxacin [2].
The Global Prevalence Study of Infections in Urology study documented how the transrectal approach is more prevalent among urologists (97%), as well as quinolones are the most widely used prophylaxis (91%).
However, especially at our latitudes, in recent years there has been developed Escherichia coli strains resistant to fluoroquinolones.
A recent study by Taylor et al, which evaluated 865 patients, that underwent transrectal prostate biopsy at the Vancouver General Hospital, showed that 19% of the subjects presented coliform strains resistant to ciprofloxacin, and the patients most at risk of developing these resistances were patients with cardiac valve replacement history and who had used fluoroquinolones within the previous 3 months [3].
The aim of our study was to evaluate efficacy and safety of a new phrophylaxis protocol using gentamicin 3 mg/kg in association with metronidazol 500 mg single shot in patients undergoing 20 cores transrectal ultrasound guided prostate biopsy in a single urologic center in Italy.

Materials and Methods

A prosepective study was conducted between June and Decemeber 2016 in our center; we prospectively evaluated 136 patients undergoing 20 core ultrasound prostate biopsy.
The procedures were performed according to the indications of the EAU Guidelines for prostate cancer detection or in adherence of a prostate cancer active surveillance protocol.
The following pre operative characteristics were registered and analyzed: age, comorbidities according to Chralson comorbidity index, serum total PSA. Patients were pre operative evaluated with urinalysis and urin culture.
Prior to ultrasound, a digital rectal exam was conducted and prostate volume was extimated trough a rectal ultrasound.
On the morning of the procedure, rectal enema was performed, and antibiotic prophylaxis with gentamicin 3 mg/kg and metronidazol 500 mg was administered to all patients.
All the patients underwent a 20 cores transrectal ultrasound guided prostate biopsy and were discharged in the same day.
Two weeks after the procedures the patients were evaluated in ou outpatients clinic, with the aim to communicate the histological examination and to assess possible complications.
Pre and post operative complication were recordered and registerd according to Clavien Dindo classification.

Results

We prospectively evaluated 136 patients that received single shot prophylaxis with gentamicine 3mg/kg and metronidazol 500 mg; 98/136 (72%) received metronidazol ev, whereas 38 (28%) x os.
Mean age of the cohort was 65.71 + 8.49 years, whereas more represented Charlson comorbidity index was 0 (65%).
Mean PSA was 11.32 + 19.00ng/ml and mean prostate volume was 42.91 + 20.99cc.
59% of the patients presented a negative rectal examination; mean operative time was 11.52 + 5.32min .
Only 12 pts had a positive urine culture, and only one of this was resistant to quinolones; 10/53 rectal swabs was positive, with one ESBL E. Coli resistant to quinolones.
22% of our patients developed fever or dysuria after the procedure; only 4/29 presented a positive urinalysis, and none of these was quinolones resistants; moreover, 5 patients presented positive haemoculture, only one resistant to quinolones.
Due to the high incidence of fever and prostatitis, we evaluated the presence of complications risk factors.
The two groups, nevertheless, did not presented any differences regarding age (65.6 + 8.26 VS 63.67 + 9.23), CCI, presence of positive urine culture or positive rectal swab ( all p > 0.05).

Discussions

In our cohort, the presence of fluoroquinolones resistant strains in urinary culture was lower than expected.
Nevertheless, 22% of our patients developed fever or acute prostatitis after the procedure, documenting that a one shot prophylaxis with gentamicine 3 mg/kg and metronidazol 500 mg is not a safe or effective pre operative prophylaxis.
Our study presents, moreover, possible limitations, as the single center design, the multisurgeon basis, the relatively low number of patients enrolled and lack of randomization.
Larger, randomized prospective trials are needed, with the aim to establish a safer and cost effective prophylaxis for patients undergoing ultrasound guided rectal prostate biopsy.

Conclusion

In our cohort, the presence of fluoroquinolones resistant strains in urinary culture was lower than expected, whereas the post procedure fever / prostatitis / readmission rate was significatively higher than in literature (22%; 29/136 patients).
We did not, find, moreover, any differences between the two groups of analyzed patients; our data suggest, therefore, that a one shot prophylaxis with gentamicine 3 mg/kg and metronidazol 500 mg is not a safe or effective procedure for patients undergoing transrectal ultrasound guided prostate biopsy.
Due to the limitations of our study, larger randomized trials are needed, with the aim to establish a cost effective prophylaxis.

References

1. Linvert K.A., Kabalin J.N., Terris M.K. Bacteremia and bacteriuria after transrectal ultrasound guided prostate biopsy. J Urol. 2000;164:76–80.
2. Aron M, Rajeev TP, Gupta NP. Antibiotic prophylaxis for transrectal needle biopsy of the prostate: a randomized controlled study. BJU Int 2000 Apr:85(6):682-5.
3. Taylor S, Margolick J, Abughosh Z, Goldenberg SL, Lange D, Bowie WR, Bell R, Roscoe D, Machan L, Black P. Ciprofloxacin resistance in the faecal carriage of patients undergoing transrectal ultrasound guided prostate biopsy. BJU Int. 2013 May;111(6):946-53.

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