Peritoneal Dialysis-associated Peritonitis Due to Streptococcus oralis Three Weeks after Peritoneal Dialysis Initiation

Abstract

A 60-year-old man with end-stage renal disease due to nephrosclerosis had a peritoneal dialysis catheter (PD) embedded with stepwise initiation of peritoneal dialysis using Moncrief and Popovich's technique three months ago. PD was initiated three weeks after creating an exit site. He presented with abdominal pain and fever a day before admission and was diagnosed with PD-associated peritonitis caused by Streptococcus oralis. Medical consultation after admission revealed a history of wisdom tooth extraction following PD catheter placement, resulting in delayed wound healing. Transient bacteremia can occur after tooth extraction, leading to PD-associated peritonitis. Contemplating the oral milieu in patients undergoing PD is pertinent.

Introduction

Peritoneal dialysis (PD)-associated peritonitis is a severe complication that leads to a decrease in fluid and solute removal, PD catheter removal, transition to hemodialysis (HD), encapsulation peritoneal sclerosis (EPS), and mortality (1-5). Exogenous infections, such as touch contamination and exit-site and tunnel infections, are the most common routes of infection. However, peritonitis arising from an intestinal source or bacteremia, which are the etiologies of endogenous infections, is also important (6,7).

Transient bacteremia after dental procedures is widely recognized and may lead to peritonitis (8,9). Streptococcus oralis is a member of the viridans group streptococci (VGS) that form the normal flora of the nose, oropharynx, skin, gastrointestinal tract, and female reproductive system (10,11). Few cases of PD-associated peritonitis due to S. oralis have been reported, although none have been associated with dental procedures or oral infection (12-14).

We herein report a case of PD-associated peritonitis due to S. oralis following a dental procedure that developed three weeks after PD initiation.

Case Report

A 60-year-old man with end-stage renal disease selected PD as renal replacement therapy. His medical history included hypertension, dyslipidemia, and hyperuricemia, for which he took pitavastatin and febuxostat daily. His activities of daily living were unremarkable, and he was a nonsmoker and did not consume alcohol regularly.

Three months prior, a PD catheter had been inserted by stepwise initiation of PD using Moncrief and Popovich's (SMAP) technique. The exit site had been created three weeks before admission, and PD had been started on the same day. His PD exchange procedure was uneventful, and he was discharged. His PD prescription consisted of 2 ambulatory exchanges of 2-liter (Reguneal LCa 1.5%™; Baxter, Tokyo, Japan) dwell volume during the day and at night. He used an ultraviolet (UV) light-based PD catheter connection system (Tsunagu^Ⓡ; Baxter).

One day before his admission, he was transported to another hospital with complaints of abdominal pain and a fever. He was treated with intravenous ampicillin sulbactam after blood and peritoneal fluid culture for suspected PD-associated peritonitis. Initially, his blood pressure was stable; however, the next day, his systolic blood pressure dropped to 60 mmHg. As he was unresponsive to saline administration, he was treated with vasoactive agents (noradrenaline and vasopressin), and his systolic blood pressure rose to 80 mmHg. The patient's antibiotic treatment was changed from ampicillin sulbactam to intravenous meropenem and intraperitoneal cephazolin, and he was transferred to our hospital.

On admission, he was alert and oriented. A physical examination demonstrated a blood pressure of 92/61 mmHg on vasoactive agents (noradrenaline and vasopressin), respiratory rate of 12 breaths per minute, heart rate of 94 beats per minute, temperature of 36.9°C, and oxygen saturation of 99% on a nasal cannula with an oxygen flow rate of 2 L/min. No physical abnormalities were observed except for muscular defense and tenderness throughout the abdomen. There were no findings suggestive of exit site or tunnel infection. Blood laboratory data showed the following: white blood cell (WBC) count, 18,000 /μL; hemoglobin, 9.6 g/dL; platelets, 261,000 /μL; sodium, 138 mmol/L; potassium, 3.1 mmol/L; chloride, 106 mmol/L; creatinine, 6.33 mg/dL; blood urea nitrogen, 48.5 mg/dL; albumin, 2.7 g/dL; C-reactive protein, 19.96 mg/dL; total bilirubin, 0.9 mg/dL; aspartate aminotransferase, 16 IU/L; alanine aminotransferase, 30 IU/L; procalcitonin, 64.56 mg/dL; and endotoxin was undetectable. An arterial blood analysis showed a pH of 7.348, PCO₂ of 39.0 mm Hg, HCO₃^- of 19.4 mmol/L, lactate of 27 mg/dL (reference range, 4-14 mg/dL), and anion gap of 15 mmol/L, indicating lactic acidosis. The PD effluent was cloudy, with a WBC count of 2,095 /μL (neutrophils, 50%; macrophages, 15%). Contrast-enhanced computed tomography (CT) of the abdomen did not reveal any abscess in the abdominal cavity or around the PD catheter. He was diagnosed with septic shock due to PD-associated peritonitis.

Although third-generation cephalosporin or aminoglycoside are recommended for Gram-negative coverage in the 2022 guidelines of the International Society for PD (ISPD) (15), we administered intravenous meropenem in addition to intraperitoneal cefazolin and intravenous vancomycin to cover for Gram-negative bacteremia with extended-spectrum beta-lactamase (ESBL)-producing pathogens. The 2022 ISPD guidelines recommend first-generation cephalosporins or vancomycin as empiric therapy for Gram-positive coverage. Since vancomycin is inferior to cephazolin in antibacterial activity against methicillin-susceptible Staphylococcus aureus (MSSA) (16), we administered both vancomycin and cephazolin to address both methicillin-resistant Staphylococcus aureus (MRSA) and MSSA infections.

He recovered from a state of shock, and the administration of vasoactive agents was stopped that day. The WBC count in the PD effluent had decreased to <100/nL on day 10 (Figure). On day 11, S. oralis was detected in the PD effluent culture at the previous hospital. Two sets of blood cultures obtained simultaneously turned out to have a negative result. The dental question revealed that the patient had undergone extraction of a wisdom tooth after two days of prophylactic oral cefcapene pivoxil hydrochloride administration one week before initiating PD. Although this had delayed wound healing after tooth extraction, it had not been reported to his attending doctor at his clinic appointment before PD initiation. The wisdom tooth extraction scar was slightly erythematous but not painful. As S. oralis is susceptible to a wide range of antibiotics, antibiotics were changed to intravenous administration of cephazolin only. Although the 2022 guideline of ISPD recommends two weeks of appropriate antibiotics for streptococcal peritonitis (15), an intermittent fever was occasionally observed despite a decreased WBC count in the PD effluent. We administered antibiotics for approximately three weeks until the fever disappeared. Transthoracic echocardiography showed mild myocardial hypertrophy but no vegetation.

Figure.

Clinical course after admission. CEZ: cefazolin, MEPM: meropenem, NAD: noradrenaline, VAP: vasopressin, VCM: vancomycin, i.p.: intraperitoneal injection, i.v.: intravenous injection

His clinical course was uneventful, and he was transferred to the previous hospital on day 23. During hospitalization, dialysis management was switched from PD to HD. The patient resumed PD one week after transfer and was discharged after confirmation of no recurrence of peritonitis.

Discussion

S. oralis is a VGS, which are the common cause of infective endocarditis and bacteremia associated with dental procedures (17). PD-associated peritonitis due to S. oralis is rarely reported, and no cases associated with dental procedures have been cited (12-14). In our case, although touch contamination via saliva could not be ruled out, the patient had used a UV light-based PD catheter connection system during the PD exchanges. Furthermore, we confirmed that the patient was able to perform the PD exchange procedure uneventfully on his own at the time of PD induction and that he practiced masking and hand washing during the exchange. Touch contamination therefore seemed unlikely, as the patient had developed peritonitis during the delayed wound healing following tooth extraction.

Although there have been no previous reports of PD-associated peritonitis resulting from S. oralis bacteremia, S. tigurinus, a VGS like S. oralis, was detected by 16S rRNA gene sequencing analysis from blood and peritoneal fluid in patients with end-stage renal failure and liver failure (18). In that report, the oral cavity was assumed to be the entry site for S. tigurinus. PD-associated peritonitis may have occurred in the present case due to bacteremia after dental procedures.

The SMAP technique used in our case is a stepwise PD induction method. The PD catheter is inserted into the abdominal cavity, an external portion of the catheter is buried temporarily under the skin, and the exit site is made at the time of PD induction. Aseptic formation of a subcutaneous tunnel is expected to prevent catheter-related infection (19). Since the SMAP technique allows the timing of PD initiation to be adjusted, if delayed wound healing after tooth extraction had been known in advance, PD initiation could have been postponed to prevent peritonitis.

The 2016 guidelines of ISPD state that streptococci frequently originate from the mouth and that transient bacteremia is common after dental procedures and may lead to peritonitis. Prophylactic antibiotics before extensive dental procedures may be reasonable (without grading) (20). The patient had received prophylactic oral cefcapene pivoxil hydrochloride prior to tooth extraction and was well-sensitive to this antibiotic. However, the efficacy of prophylactic administration of antibiotics prior to dental procedures has not been established (21). The 2022 guidelines of ISPD only state that clinical trials are also required to assess the benefits and harms of antibiotic prophylaxis before gastroscopy and dental procedures (15). Patients with end-stage renal disease have impaired immunologic responses. In the present case, wound healing was delayed after tooth extraction, so a longer period of oral antibiotics may have been necessary.

Oral hygiene affects a variety of diseases. Patients with chronic kidney disease who have poor oral hygiene have an increased risk of overall and cardiovascular death via inflammation, infection, protein energy loss, and atherosclerosis (22). In a prospective international cohort study of 675 PD patients participating in the PD Outcomes and Practice Patterns Study (PDOPPS), poor oral health was associated with an increased risk of peritonitis and death. That study observed a 24% prevalence of poor oral health, and 65% of the participants did not consider their oral hygiene a significant handicap (23). A retrospective observational study in Japan reported that improving oral hygiene habits was significantly associated with less-frequent peritonitis (24). In the present case, the patient was found to have undergone dental procedures after developing peritonitis. PD hand hygiene, related to the PD exchanges as well as oral hygiene, is also important for PD patients.

PD-associated peritonitis due to VGS responds well to antibiotics and carries a lower mortality risk than other streptococci despite an increased risk of subsequent refractory peritonitis after the index episode (25). Our patient initially developed septic shock but was soon weaned from vasoactive agents. Among the two earlier case reports of PD-associated peritonitis caused by S. oralis, one relapsed after several months (13); however, the other had no recurrence for nine months (14). At the time of writing this report, our patient had not experienced recurrent peritonitis for three years since these events. The period during which the patient had undergone PD was the coronavirus disease 2019 (COVID-19) pandemic. With the advent of this pandemic, hand washing and mask wearing became thoroughly promoted in Japan. In China, where infection control is as strict as in Japan, the incidence of peritonitis in the six months before and after the start of the COVID-19 pandemic showed a decrease in cases caused by Gram-positive infections following the start of the pandemic (26).

While the present study emphasizes the importance of hand hygiene, we suspect that adherence to mask wearing is also essential. The reason why peritonitis caused by S. oralis did not recur in this patient after the index episode may be the absence of contamination from saliva due to wearing a mask as well as the absence of oral disease.

Conclusions

This report describes a case of PD-associated peritonitis due to S. oralis following a dental procedure that developed three weeks after PD initiation. Dental procedures can cause PD peritonitis via transient bacteremia. In the case of PD induction by the SMAP technique, it is necessary to ensure that there are no signs of infection at the time of PD initiation. PD patients may not pay sufficient attention to their oral health and should be instructed in not only hand hygiene but also oral hygiene.

Informed consent was obtained from the patient.

The authors state that they have no Conflict of Interest (COI).