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Associate Professor of Urology
Department of Urology
Malmö University Hospital
Urology is a growing speciality as a consequence of the increasing average age of the population, significant technical advances and improved care which have led to a subsequent broadening of the indications treatable by surgery.
Technical advances have dramatically changed the surgical approach to most treatments. While open surgery is performed to remove a substantial number of malignant tumours, eg, localised prostate cancer, invasive bladder cancer, and cancer of the kidney, testis and penis, and to restore a functional, low-pressure urinary tract in case of anatomic abnormal changes, the laparoscopic approach is gaining in importance in several European centres. Kidney stones, when requiring surgical treatment are, nowadays, preferably treated by extracorporeal shock-wave lithotripsy (ESWL) or endourological procedures, while open procedures have become rare.
Infections in urology
Nosocomial or hospital-acquired infections are estimated to affect 5–10% of all patients admitted to hospital.(1) Urinary tract infection (UTI) is the most common healthcare associated infection, accounting for approximately one-quarter of all infections.(2,3) Most infections are limited to catheter-associated bacteriuria, but they may easily develop into a complicated upper urinary tract bacterial infection or septicaemia. Gram-negative bacterial strains are the most frequent pathogens (approximately 60–80%) although Gram-positive species are present in a substantial number of cases (some 20–40%).(4)
All urological instrumentation may be followed by UTI, ranging from simple bacteriuria to life-threatening septicaemia. These infections can be prevented by a series of measures (Panel 1) including proper antibiotic prophylaxis. The expected frequency of infection is clearly associated with the type of urological diagnosis and therapeutic procedure, and is shown in Table 1.(4) For open surgery, the rate of surgical site infection will depend on the level of contamination of the surgical wound class.(5) Bacteriuria and complicated UTI are the most frequent infectious complications in endourological surgery.
In opting for antibiotic prophylaxis, the urologist has to consider:
General patient related risk factors for surgical site infections are given in Panel 2. Moreover, there are endogenous risk factors to consider, such as anatomical abnormalities, genetic determinants and concomitant diseases. Also, there are exogenous risk factors such as treatment with an indwelling catheter, the presence of a urinary tract calculus or implanted devices. The type of procedure is of particular importance – a short “easy” intervention will, for instance, place the patient at lower risk as compared with a more difficult, time consuming intervention. The pre-operative assessment is, thus, of great importance in determining choice of antibiotic prophylaxis, type of drug, administration route and length of the prophylactic course.(4)
No clearcut information and recommendations can be issued, as there are great variations in Europe regarding bacterial distribution and, especially, bacterial sensitivity to different antibiotics.
Antimicrobial resistance is usually higher in the Mediterranean countries than in northern Europe, and correlated to the four-fold difference in consumption of antibiotics. For instance, ampicillin resistance in Spain and Portugal are reported to be 54% and 45% respectively, as compared with 16% in Sweden. Quinolone resistance is reported at over 20% in several southern European countries but only a few percent in the northern countries.(6) Local knowledge of these two aspects of a pathogens is, consequently, of paramount importance when setting up a rational antibiotic prophylactic policy. It also highlights the need for controlling the use of antimicrobial agents.
Pathogen type varies according to the procedure. Gram-negative strains will be the most frequent in endoscopic procedures and clean contaminated operations (those involving the opening of the urinary tract and/or the bowel), while Gram-positive strains may cause wound infections in prosthetic implant surgery.
Choice of antimicrobial agents
Almost all antimicrobial agents could be used for prophylaxis. Oral administration is as good as other routes in most clinical situations, such as core biopsy of the prostate, transurethral resection of the prostate and standard ureteroscopy, while intravenous administration is recommended for longer operations involving the bowel (reconstructive surgery), complicated endourological interventions and for patients at high risk.
It is advisable to use different drugs for prophylaxis and therapy, reserving the more powerful antibiotics for therapy. The drug’s spectrum of action should cover most expected procedure-related pathogens, keeping the local susceptibility pattern in mind. It is also reasonable to use different drugs to reduce the ecological pressure. The regimen’s length should be kept as short as possible and, regrettably, we still have too little evidence-based information about rational length of antibiotic prophylactic regimens for most urological procedures.
Principles of antibiotic prophylaxis
It is important to keep in mind that the use of antibiotics in urological surgery is only one of several measures aimed at preventing the emergence of a healthcare associated infection in conjunction with diagnostic and therapeutic procedures. A working group of the European Society of Infection in Urology, a member of the European Association of Urology, has developed guidelines for the treatment of genitourinary infections and practical antibiotic prophylaxis to support European urologists.(7)
As a baseline, urological operations follow the same principles as general surgery. Clean operations – patients considered as “free” from bacterial contamination at the time of intervention, do usually not require antibiotic prophylaxis. On the other hand, patients undergoing clean contaminated procedures should be given antibiotics with a prophylactic intention. Those undergoing contaminated and dirty operations are given antimicrobial agents with a therapeutic intention.
A source of controversy in urology is the relevance of the “natural” bacterial load harboured in the urethra, vagina and prostate. This load is of such importance in patients suffering from a disease of the lower genitourinary tract that some authors consider the local environment as contaminated.(8) This is also probably true for endourological interventions such as percutaneous stone surgery and advanced ureteroscopic operations(9) because the upper urinary tract can harbour bacteria despite a “sterile” urine culture.
Transurethral resection of the prostate is the best-studied urological intervention. A meta-analysis has revealed the advantages of a short- to medium-term regimen to protect the patients against UTI and, especially, to save a substantial number of patients from upper UTI and septicaemia.(10)
Patients with an indwelling catheter, nephrostomy tube or other stent device should be considered as having bacteriuria. They should be treated in advance, between three and seven days prior to surgery, to have sterile urine at the time of surgery, and be covered well beyond the intervention, usually for some seven to 10 days or longer, depending on the type of operation and underlying condition.(9)
There is a given timeframe during which antibiotic prophylaxis should be administered. The optimal time appears to be up to two hours before but not later than two hours after the start of an intervention.(11,12) The rationale for this is to reach a peak concentration at the time of highest risk during the procedure and an active concentration throughout the operation. A prolonged, difficult operation could require repeated dosage.
Antibiotic prophylaxis is one of several measures used to reduce the incidence of healthcare associated infections following urological procedures. It requires careful preoperative assessment and individualisation considering the patient’s characteristics and potential risk factors, expected pathogens and their susceptibility profile, ecological aspects, pharmacological properties of different antibiotics, local medical strategies and costs. A judicious use of antibiotic prophylaxis will protect the patient against hazardous complications, reduce overall costs and limit the overall use of antimicrobial agents. However, our knowledge is still limited and further relevant procedure related clinical studies are highly desired.