|Year : 2017 | Volume
| Issue : 2 | Page : 31-34
Posttransplant urinary tract infections and surgical site infections among renal transplant recipients in a transplant unit in Sri Lanka
Lilani Indrika Karunanayake1, Poogoda Kankanange Harischandra2, UB Rambukwella2, CT Hapuarachchi3, Tshokey Tshokey4
1 Department of Microbiology, Teaching Hospital, Kandy, Sri Lanka
2 Department of Surgery, Transplant Unit, Teaching Hospital, Kandy, Sri Lanka
3 Department of Bacteriology, Medical Research Institute, Colombo, Sri Lanka
4 Department of Microbiology, Teaching Hospital, Kandy, Sri Lanka; Department of Laboratory Medicine, Jigme Dorji Wangchuck National Referral Hospital, Thimphu, Bhutan
|Date of Web Publication||12-Sep-2017|
Department of Laboratory Medicine, Jigme Dorji Wangchuck National Referral Hospital, Thimphu, Bhutan
Source of Support: None, Conflict of Interest: None
Aim: Kidney transplant (KT) recipients are at higher risks of infections due to the chronic disease conditions, the surgical procedure and immunosuppressive therapy following transplantation. We aimed to assess the incidence and the microbiology of urinary tract infections (UTIs) and surgical site infections (SSIs) in KT recipients at the transplant unit in Kandy Teaching Hospital, Sri Lanka. Methods: A prospective, descriptive study was carried out in patients undergoing KT for 6 months postoperatively. A urine full report and culture were carried out before transplantation and on days 1, 3, 7 and monthly for 6 months posttransplantation. Urine specimens yielding growth of ≥105 CFU/ml were considered significant. In addition, patients were screened preoperatively for Staphylococcus aureus colonization by multi-site swabbing. The surgical sites were inspected daily for SSI. Results: Thirty-nine patients were recruited in the study. Two patients (5.1%) had preoperative UTI and 4 (10.3%) developed UTI within 6 months. Majority of post-KT UTI (75.0%) occurred in the 1st month. UTI was commonly due to coliforms (50.0%) while S. aureus and Pseudomonas spp. accounted 25% each. All screened patients were colonized with S. aureus and majority (62.9%) were methicillin-resistant S. aureus. Only 3 (8.6%) KT recipients had SSIs. Conclusion: The incidence of UTI in KT recipients within the first 6 months was 10.3%, and majority occurred in the 1st month. Patients, who were treated for UTI preoperatively, did not develop post-KT UTI. Coliforms were the most common organism. Although there was high S. aureus colonization index, the incidence of SSI in post-KT recipients was low.
Keywords: Kidney transplant, Sri Lanka, surgical site infections, urinary tract infections
|How to cite this article:|
Karunanayake LI, Harischandra PK, Rambukwella U B, Hapuarachchi C T, Tshokey T. Posttransplant urinary tract infections and surgical site infections among renal transplant recipients in a transplant unit in Sri Lanka. Indian J Transplant 2017;11:31-4
|How to cite this URL:|
Karunanayake LI, Harischandra PK, Rambukwella U B, Hapuarachchi C T, Tshokey T. Posttransplant urinary tract infections and surgical site infections among renal transplant recipients in a transplant unit in Sri Lanka. Indian J Transplant [serial online] 2017 [cited 2020 Jul 5];11:31-4. Available from: http://www.ijtonline.in/text.asp?2017/11/2/31/214385
| Introduction|| |
Kidney transplant (KT) recipients are at high risk of infections, both due to immunosuppression caused by the chronic disease, surgical procedure and the immunosuppressive therapy following transplantation. Urinary tract infections (UTIs) are the most common infections following KT  and are associated with increased graft failure and mortality. The global prevalence of post-KT UTI varies between 6% and 86%, and they commonly occur within the 1st year, especially the first 3–6 months following KT.
Commonly, asymptomatic bacteriuria may precede clinically significant UTI in these patients. They are often associated with acute pyelonephritis and bacteremia which may rapidly progress to irreversible urosepsis. Therefore, many experts recommend long-term antibiotic therapy for UTI within the first 6 months following KT  and screening and treatment of asymptomatic bacteriuria during this period.
Surgical site infections (SSIs) following KT lead to significant morbidity, increased antibiotic use and healthcare cost and prolonged hospital stay. Prevalence of SSIs following KT, which is considered a clean-contaminated surgery, ranges from 0% to 11% and 2%–7.5% with or without antibiotic prophylaxis, respectively. Staphylococcus aureus is an important pathogen causing SSI in KT recipients, and colonization with this organism is known to increase the risk., Preoperative screening for S. aureus carriage followed by decolonization strategies has been practised to reduce SSIs in cardiothoracic and orthopedic surgery. Some centers screen all electively admitted patients for methicillin-resistant S. aureus (MRSA). However, until now, there is no clear consensus on MRSA screening and decolonization for renal transplantation.
Kidney transplantation is routinely carried out at two centers in Sri Lanka; the transplant units in National Hospital of Sri Lanka, Colombo and Teaching Hospital Kandy (THK), Kandy. The transplant unit in THK performs about 80–85 living donor transplants and 5–8 cadaver donor transplants annually. There is a dedicated operating room with laminar airflow for KT. Both the donor and recipients undergo extensive routine screening as per KT protocols before the transplantation. Screening for S. aureus colonization was not routinely done. Patients with symptomatic or asymptomatic UTI from the preoperative urinary investigations were given appropriate antibiotic treatment and cure established before proceeding for KT. The KT recipients are given two doses of Augmentin 1.2 g through intravenous infusion as surgical antibiotic prophylaxis followed by oral Cotrimoxazole 480 mg daily up to 6 months as Pneumocystis carinii pneumonia prophylaxis with oral nystatin for 1 month posttransplant. The recipients are actively followed up, and treatments for conditions such as UTI or chest infection are initiated immediately at their earliest presentations.
Studies assessing the incidence and bacteriological profiles of posttransplant UTI and SSI among the KT recipient population in Sri Lanka are limited. Therefore, we carried out this study to identify the incidence and the bacterial etiology of UTI and SSI in post-KT patients in THK and to determine the risk associated with S. aureus colonization in post-KT infections.
| Methods|| |
A prospective, descriptive study was carried out from September 2009 for 6 months. All patients undergoing KT were enrolled after taking informed consent.
For all participants, a urine full report (UFR) and culture were obtained before the transplantation and on postoperative days 1, 3, 7 and monthly for 6 months following transplantation, and at any time, the patients became symptomatic. The urine specimens were processed at microbiology laboratory, THK, following standard laboratory protocols within 2 h of collection. The semi-quantitative method was used for urine culture, and a growth of ≥105 CFU/ml of urine was considered significant. Antibiotic susceptibility testing was carried out as per the Clinical and Laboratory Standards Institute guideline. Diagnosis of pre- or post-operative UTI was solely based on significant culture reports since UFR results in chronic kidney diseases are not considered reliable due to reduced urine output or anuria in some cases.
Patients were also screened for colonization with S. aureus before surgery using cotton swabs from anterior nares, throat, axillae, and perineum. Swabs from different sites were processed separately. Since it was not part of the protocol in the transplant unit, those patients colonized with S. aureus or MRSA did not undergo decolonization. Following KT, the surgical sites were inspected daily for SSI during ward rounds according to the United States Centre for Disease Control (CDC) criteria for superficial and deep incisional SSI. Swabs/pus were taken for culture from surgical wounds suspected of infection as decided by the examining surgeon. Swabs or pus thus collected were processed as per routine microbiological protocol.
| Results|| |
A total of 39 patients were recruited into the study, but preoperative urine culture results were available only in 36 patients and S. aureus screening swabs only in 35 patients.
In the preoperative urine culture, 33 of the 36 (91.7%) patients had no growth, 2 (5.6%) had preoperative symptomatic culture positive UTI with ≥105 CFU/ml of coliforms, and one patient (2.6%) had mixed growth which was not significant. Preoperative cultures were not done in two patients due to anuria.
All 35 screened patients were positive for S. aureus colonization in at least one screening swab. All the patients (100%) were positive for S. aureus in either axillary or nasal swabs while 97.1% were positive in either nasal or perineal swabs. In two patients, S. aureus was isolated only from nasal swabs. Only 54.3% of throat swabs had S. aureus. S. aureus isolated from one or more screening swabs in 22 of the 35 patients (62.9%) was MRSA [Table 1].
|Table 1: Summary of preoperative screening for Staphylococcus aureus by multi-site swabs (n=35)|
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The two patients with positive preoperative UTI were treated before transplantation, and cure was confirmed with a repeat urine culture after appropriate treatment. Neither of these two patients developed UTI following transplantation within the first 6 months. Four patients (10.3%) developed culture-positive UTI within the 6 months follow-up period postoperatively and were treated adequately. Of these four patients, 3 (75%) of them had UTI within the 1st month following KT. The majority (50%) of the posttransplant UTI were due to coliforms while S. aureus and Pseudomonas spp. were isolated in one patient each (25%). On day seven post-KT, four patients had positive urine culture with multiple mixed organisms but not significant quantitatively [Table 2].
Among those positive for S. aureus screening, one patient whose nasal and axillary swabs were positive had UTI with S. aureus on the 1st day posttransplant. Only 3 (7.7%) cases of SSIs were identified among the 39 patients; one deep and two supercial incisional SSIs. In the first patient, an extensive hematoma developed on the 2nd day posttransplant. Pus culture in this patient grew S. aureus. The patient died of pneumonia on posttransplant day twenty. This patient was positive in all four preoperative screening swabs for S. aureus. The second patient had a liquefying hematoma and pus culture did not yield any growth. He was also positive in all four sites in preoperative screening. The third patient had a slight discharging SSI. Pus culture was not done. He had a positive nasal swab for methicillin-sensitive S. aureus (MSSA) on preoperative screening. These two patients responded well to antibiotic treatment.
| Discussion|| |
UTIs remain among the most common infectious complication following KT in many studies.,,, Some studies have recommended surveillance for UTI for 3–6 months following KT to diminish the risk of renal failure since most episodes of infection-related renal impairment occur within this period.,
In our study, the incidence of UTI in renal transplant recipients was 10.3%. It was much higher in similar studies in other countries.,, In most studies, the most common bacteriological agent was Escherichia More Details coli., Similarly, in this study, the majority of posttransplant UTI were due to coliforms (50%). Interestingly, S. aureus and Pseudomonas spp. were also isolated from one patient each.
Similar to other studies, UTI was more common in the early posttransplant period with 75% occurring within the 1st month following KT in this study. The two patients who were treated for UTI preoperatively did not develop UTI following KT indicating the importance in the detection and treatment of preoperative UTI.
Mertz et al. had shown that S. aureus carriage is associated with an increased risk of infectious complications following surgery in patients with end-stage renal failure. Their study had utilized only throat and nasal swabs for detection of carriage. We used combined four-site swabbing which would have further increased the sensitivity.
A Scottish study for NHS Scotland found that universal nasal swabbing for MRSA appeared less effective in identifying patients with MRSA carriage. Using a combination of multiple body site swabs would increase ascertainment within a universal screening programme but at a significant cost in terms of staff time and resources. Nasal swabbing alone had identified only 66.4% of MRSA-positive admissions. For an additional second swab, detection increased by 2.4% by adding axilla screening, by 10.1% by adding throat screening, and by 15.8% by adding perineal screening. Optimum numbers of MRSA colonization (91.6% of gold standard positives) were detected by screening all four sites (nasal, throat, axillary, and perineal) but excluding axilla screening reduced this only minimally (90.3%).
In our study, the preoperative screening showed all the patients to be colonized with S. aureus with an MRSA rate of 62.9% (22/35). Local data showed the prevalence of MSSA and MRSA in ward setting at THK was 51.5% and 48.5%, respectively, with a higher MRSA prevalence in Intensive Care Unit (ICU) setting. The 100% colonization index in our study may be due to the fact that these patients had frequent hospital visits with regular hemodialysis and frequent invasive procedures.
Of the 22 (62.9%) MRSA-positive patients, 68.2% were from perineal swabs, 40.9% had positive nasal swabs, 27.3% were from axillary, and 13.6% were from throat swabs. In contrast to the study by Smith et al., a combination of perineal and nasal swabbing had identified 90.9% of the MRSA-positive patients. However, in both studies, the most sensitive dual swabbing for MRSA was achieved with combining nasal and perineal swabs.
In our study, the assessment of S. aureus carriage as a risk factor for postoperative infection among MRSA- and MSSA-positive patients was 2.44% and 4.88%, respectively. At the time of the study, preoperative swabbing for S. aureus carriage was not practised in the unit and only peroperative prophylaxis was used in all patients.
The incidence of SSI in the transplant unit, THK, was 7.7%. The low incidence of SSI in postrenal transplant patients despite the high carriage of S. aureus before transplantation implies that a dedicated operating theatre with laminar airflow system, strict adherence to standard precautions, good surgical techniques, and the use of antibiotic prophylaxis would have played a role.
| Conclusion|| |
The incidence of UTI in post-KT recipients was 10.3% within the first 6 months and majority occurred in the 1st month. Coliforms were the most common causal agent. Post-KT UTI was not seen in patients treated for preoperative UTI. This reinforced the importance of preoperative screening for UTI, early detection, and appropriate treatment.
The low incidence of SSI (7.7%) despite high carriage of S. aureus in post-KT patients was noteworthy. However, due to the complex nature of surgery and the use of immunosuppressive therapy, preoperative screening and decolonization regimen for S. aureus may be useful in these patients to minimize the risks of morbidity and mortality. A combined approach using nasal and axillary or nasal and perineal swabbing appears to be a cost-effective and acceptable alternative to four-site swabbing.
The authors acknowledge the assistance of staffs of microbiology laboratory and nursing staff of ttransplant unit, THK, Kandy and also all the participants of the study.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2]