Percutaneous nephrolithotomy, as is known, is a commonly used surgical procedure for nephrolithiasis. Despite use of a prophylactic antibiotic, postoperative bacteremia and fever are reported as 37% and 74% [5
]. In a surgical practice, despite application of prophylaxis and preoperative sterile urine, life-threatening systemic infections may develop [6
]. No proved use of prophylactic antibiotic with preoperative sterile urine exists; however, short-term prophylaxis is generally preferred. This short-term prophylaxis is usually maintained up to the postoperative 48th hour [7
]. Previous studies show that preoperative single antibiotic dose will be enough for patients with preoperative sterile urine culture, without a risk of upper urinary tract infection. In our study, one can state that there is no statistical difference between CTX and CIPRO either for single dose or long-term use.
The study of Charton et al. sparked a critical argument about prophylaxis before PNL. That study stated that no major septic complication was observed without prophylaxis. Only 10% of the patients were exposed to fever and 35% of them suffered from urinary tract infection but they said that short-term prophylaxis was more reasonable [8
]. Another study by Mariappan et al. alleged that ciprofloxacin prophylaxis administered for one week before PNL significantly decreased the urosepsis risk in 98 patients with stones >20
mm and/or pelvicaliceal dilatation that displays a fourfold risk of increase. That study 18 of 46 (39%) patients in the control group developed SIRS, whereas only 7 of 52 (13.4%) patients in the treatment group developed SIRS. They also reported that one-week administration of ciprofloxacin prophylaxis decreased positivity of pelvicaliceal culture three times, stone culture positivity two times, and risk of developing SIRS three times. That study indicated that 2 patients developing septic shock were diagnosed with positive stone culture, while 4 of 7 patients developing SIRS in the treatment group with infected stone culture, and one of them had positive pelvicaliceal culture [6
As we know, SIRS is an important predictive factor for urosepsis. Prevalence of bacteruria or bacteremia with SIRS is accepted as urosepsis in our study. SIRS incidence after PNL is reported as 15.5% for the ciprofloxacin group and 8.8% for the ceftriaxone group. An important result concluded from our study is that 3 patients accepted as urosepsis are from ciprofloxacin group in which SIRS is seen to be relatively high. In the study arranged by Mariappan et al. that included 54 patients, while 42% of patients had positive upper urinary tract culture (pelvic and stone), only 5.6% of them had positive urine culture from bladder. There was no identical colonization between upper and lower urinary tract in their study [9
]. In our study preoperative urine culture was sterile for all patients. 33.3% of patients had positive stone culture and pelvicaliceal culture. It is seen from our study that urine from bladder does not reflect all urinary system.
The incidence of infected stone culture is defined as 5.6–77.3% [10
]. According to Gault et al. low incidence of infected stone (5.6%) in their study depends on long-term preoperative treatment with fluoroquinolones and lower prevalence of infected stone in Canada [10
]. Fowler reported a 77.3% incidence rate and found that only 12.5% of patients with infected stone had positive urine culture form bladder [11
]. Similarly, McCartnaey and Bratell repeated the weak correlation between infected stone and urine culture from bladder [12
]. Dogan et al. evaluated the data retrieved from 338 patients who underwent PNL retrospectively. They reported positive stone culture to be 34% (115/338) [15
]. Similarly in our study, positive stone culture rate is 31.1% although all patients had sterile urine preoperatively. Our study and other studies emphasize that preoperative urine culture is not a predictive factor for postoperative stone culture.
One of the interesting results of our study is that pelvicaliceal urine culture is not enough to detect positive stone culture. Only one out of 28 patients with positive stone culture had positive pelvicaliceal urine culture. Dogan et al. reported similar results. They diagnosed only one patient with positive pelvicaliceal urine culture out of 19 patients with positive stone culture [16
In our study group there was no colonization from blood culture of 3 urosepsis cases and other SIRS cases. Martin et al. observed bacteremia in only 50% of septic patients [17
]. Again, Clayman defined the post-PNL bacteremia rate as 2% [18
According to the study of Margel et al., positivity of stone or urine culture is accepted as relative risk for SIRS. They said that bladder urine culture is not enough to show an infection of upper urinary tract. In contrast, pelvicaliceal and stone culture are more powerful predictive factors for urosepsis. They also reported that bigger stones are more likely to get infected than smaller ones [19
]. Again in the same study, it is said that patients with history of urinary tract infection are exposed to a higher risk of developing SIRS [19
]. When Mariappan et al. compared different culture samples and SIRS, they found out that positive pelvicaliceal urine culture and stone culture increased risk of developing SIRS for four times [9
Shigeta et al. pointed out to a critical conclusion in their study which included 54 patients. They diagnosed 10% of the patients with an infected stone and found out that in cases of a stone size bigger than 30
mm, bacteruria is more common [20
]. In our study stone burden is related with SIRS or with urosepsis in the ciprofloxacin group but there is no such relationship with the ceftriaxone group. Similarly, Mariappan's study shows that stones are bigger in the cases developing SIRS. On the other hand, in cases without SIRS, infected stones are relatively smaller than the noninfected stones (29,8
]. In our study stone burden in cases with SIRS and positive stone culture is 4.4
, while it is 4.3
in the group with negative stone culture.
Importance of preoperative factors, such as infected stones, positive cultures, more stone burden, longer operation time, more irrigation fluid, and participating the systemic infections are reported in numerous articles [9
]. In our study, however, only operation time was found to be related with SIRS in both antibiotic groups.
Postoperative fever will not be important if patients given antibiotic pre- and postoperatively have negative urine culture, and if hemodynamically they are stabile because postoperative fever does not always mean sepsis. With regards to this issue, Cadeddu et al. stated that an urgent investigation of postoperative fever is unnecessary if preoperative sterile culture is prevalent, preoperative antibiotic is given and patient is hemodynamically stable [21
]. To our knowledge, there is no need to initiate or change antibiotics for hemodynamically stable patients with postoperative fever. But thorough management of septic complication together with a microbiologic investigation should be done with cultures during preoperative, postoperative, and febrile periods.
In our study colonization of microorganisms was not documented in every patient with postoperative fever or SIRS. Possibly, this may be because prophylactic antibiotic prevents proliferation of microorganisms, or increased inflammatory mediators trigger postoperative fever by surgical manipulation. We assume that the rates of infection and urosepsis in our series are lower than those reported in the literature, due to selection of patients with no internal problem, no risk of urinary tract infection, yet who have a normal urinary structure, or use of effective prophylactic antibiotics against microorganisms that would lead to contamination.
Truck and Bronsema mostly isolated E. coli
and usually other microorganisms like Proteus, Klebsiella, Enterobacter
, from population after PNL, during endoscopic procedures in their studies [22
]. In our study, the most commonly isolated microorganisms from all culture samples are coagulase negative Staphylococcus
, and the second one is E. coli
with a rate of 26%. Related to this, Margel et al. isolated Enterococcus
, a gram-positive bacterium with rate of 74% [19
]. In our study coagulase negative Staphylococcus
is the most commonly isolated organism from positive stone culture (64%). In the multicentre study performed by Farrell et al., ciprofloxacin was found to be quite effective against uropathogenic microorganisms. In this study antibiotic sensitivity rates of E. coli
, Klebsiella pneumonia
, Pseudomonas auroginosa
, and Proteus mirabilis are, respectively, reported to be 98%, 94%, 89% and 87% [24
]. Although we did not perform antibiotic sensitivity for all positive cultures, and gram-positive organisms were isolated usually from culture samples, isolated gram-positive and negative organisms seemed to have similar sensitivity for both ciprofloxacin and ceftriaxone.