https://ojs.wpro.who.int/ 1WPSAR Vol 13, No 4, 2022 | doi: 10.5365/wpsar.2022.13.4.960 Case Report N osocomial infection among immunocompromised patients is an emerging problem commonly encountered with multidrug-resistant Gram- negative bacteria. Ralstonia spp. are waterborne Gram- negative bacteria, ubiquitous opportunistic environmental pathogens characterized as strong biofilm producers that are resistant to most antimicrobials. Notable strains are R. pickettii, R. mannitolilytica and R. insidiosa.1 R. insidiosa has recently had increasing clinical rel- evance,2 especially in hospitals, because it can survive in different ultra- or high-purification water systems used for industrial and laboratory methods.3,4 It can contaminate purified or distilled water used for medicinal procedures or products, and can survive in low-nutrient states and be resistant to commonly used antimicrobial agents such as chlorhexidine.5 The emergence of R. insidiosa as a causative agent of nosocomial infections was reported among immunocompromised individuals in the Czech Republic, where it led to bacteraemia among eight haemodialysis patients owing to contaminated haemodi- alysis solutions.6,7 A recent report from a Chinese tertiary hospital has noted the emergence of multidrug-resistant R. insidiosa in clinical isolates.8 In January 2021, the Department of Internal Medicine – Infectious Disease and Infection Prevention and Control Committee (IPCC) in the Philippines declared an outbreak in a haemodialysis unit in Baguio City when three patients were identified with Ralstonia bacterae- mia. Haemodialysis sessions were suspended until the investigation was completed. The objectives of this study were to describe the three cases of Ralstonia bacterae- mia and to report the identification process and control measures implemented for this outbreak of R. insidiosa in a haemodialysis unit in Baguio City. CASE SERIES In this study, a confirmed case was defined as a patient who underwent haemodialysis and experienced a tem- perature of more than 38.5 °C or chills during or after a Department of Internal Medicine, Baguio General Hospital and Medical Center, Baguio City, Philippines. b Infection Prevention and Control Committee, Baguio General Hospital and Medical Center, Baguio City, Philippines. Published: 27 December 2022 doi: 10.5365/wpsar.2022.13.4.960 Ralstonia insidiosa is an opportunistic pathogen considered an emerging problem among clinically vulnerable populations such as those with chronic kidney disease. This study presents three cases of Ralstonia bacteraemia among chronic kidney disease patients in a haemodialysis unit in Baguio City, the Philippines. Case 1 was an elderly male who experienced chills during two concurrent dialysis sessions. Case 2 was a young female who also experienced chills and dizziness during a dialysis session; as this was thought to be related to hypotension, she was admitted. Case 3 was an elderly female with known hypertension and diabetes who had been newly diagnosed with chronic kidney disease; she was brought to the emergency room hypotensive, dyspnoeic and disoriented with deranged laboratory parameters and was admitted to the intensive care unit. All three cases had blood cultures positive for R. insidiosa with an attack rate of 1.67%. Drug and device tracing were conducted and environmental samples collected to identify the source of infection. A sample from the faucet of the reprocessing machine in the haemodialysis unit that was positive for Ralstonia spp. was the source of the outbreak. Control measures were implemented and the haemodialysis unit was thoroughly cleaned. No further cases were reported, with active surveillance continuing until January 2022. Taken with previously published outbreaks, these findings suggest that medical products and devices can be contaminated with Ralstonia spp. and cause illness. Early identification of cases and the source of infection is required to prevent large outbreaks in this vulnerable population. Outbreak of Ralstonia bacteraemia among chronic kidney disease patients in a haemodialysis unit in the Philippines Denmarc R Aranas,a Bernard A Demota and Thea Pamela T Cajulaoa,b Correspondence to Denmarc R Aranas (email: aranasdenmarc@gmail.com) WPSAR Vol 13, No 4, 2022 | doi: 10.5365/wpsar.2022.13.4.960 https://ojs.wpro.who.int/2 Aranas et alRalstonia outbreak in a haemodialysis unit ward. Her chest tube was removed and the tip sent for culture. Blood samples from two sites were submitted for culture and antibody sensitivity testing. The chest tube tip culture was positive for Enterococcus faecalis and the blood culture was positive for bacteraemia with R. insidi- osa. Cefepime 500 mg intravenous once daily for 7 days was given for the Ralstonia bacteraemia. The patient recovered from the bacteraemia and was discharged. Case 3 Case 3 was a 69-year-old female with known hyperten- sion and diabetes mellitus. She had a 1-month history of bipedal oedema with decreasing urine output. She reported shortness of breath and progressive bipedal oedema in November 2020. She attended a different hospital where initial tests detected elevated creatinine, after which she was admitted and managed as a newly diagnosed chronic kidney disease patient secondary to hy- pertensive nephrosclerosis versus diabetic nephropathy. On 20 December 2020, the patient had bradycardia and hypotension at 80/50 mmHg and was given a dopamine drip. She was referred to our institution for haemodialysis the next day. The patient arrived at the emergency room with symptoms of drowsiness, disorientation and episodes of desaturation at 79% when on room air, and was afebrile. She had anicteric sclera, slightly pale palpe- bral conjunctiva and positive neck vein engorgement. Her chest findings had crackles in the middle and basal lobes. The patient had bradycardia with irregular rhythm and no murmurs. Extremities had pitting bipedal oedema, grade 3. The patient was assessed as having acute respira- tory failure secondary to encephalopathy, which had re- sulted from chronic kidney disease, newly diagnosed, and itself the result of hypertensive nephrosclerosis versus diabetic nephropathy, complicated urinary tract infec- tion, pulmonary congestion, metabolic acidosis, multiple electrolyte imbalance and anaemia; uncontrolled stage 2 hypertension; diabetes mellitus type 2, non-obese, non-insulin requiring; and suspected coronavirus disease (COVID-19). The patient was admitted to the intensive care unit for close monitoring and further management, and was then initiated on haemodialysis. A complete blood count revealed increased white blood cells with neutrophilic predominance. Blood culture detected the the session with a positive blood culture for R. insidiosa from December 2020. Clinical histories and laboratory examinations were reviewed for all reported patients. Active surveillance, whereby symptomatic patients from the haemodialysis unit had specimens collected for blood culture and sensitivity testing, was initiated, and continued until January 2022. All specimens underwent sensitivity testing for a range of antibiotics. Three patients from the haemodialysis unit fit the case definition (Table 1). The haemodialysis centre has 30 units catering to 180 dialysis patients; thus, the at- tack rate was 1.67%. Case 1 Case 1 was a 70-year-old male with known stage 5 chronic kidney disease secondary to hypertensive nephro- sclerosis. He was on maintenance haemodialysis twice a week at the haemodialysis unit. During a haemodialysis session on 9 December 2020, the patient experienced chills with no associated chest pain or fever. A specimen was collected for blood culture and sensitivity testing before discharge from the haemodialysis unit. Three days later, the patient underwent his next regular haemodi- alysis with recurrence of chills. After haemodialysis, the patient was sent to the emergency room. He was awake, comfortable, not in distress and had stable vital signs. The patient has an intact right internal jugular catheter. He was sent home and advised to continue maintenance medications and haemodialysis. The blood culture revealed growth of R. insidiosa. He was prescribed co- trimoxazole 800/160 one tablet daily for 7 days for the bacteraemia. The patient recovered from the bacteraemia and was discharged. Case 2 Case 2 was a 32-year-old female with known stage 5 chronic kidney disease secondary to chronic glomeru- lonephritis. She was on haemodialysis twice a week. A few hours before admission to the haemodialysis unit on 17 December 2020, she experienced chills, dizziness and body weakness, with hypotension at 80/60 mmHg. A 500 mL fast drip of normal saline solution was given and haemodialysis continued. As the chills and body weak- ness persisted, the haemodialysis was terminated and the patient was transferred to the emergency room. She was diagnosed with sepsis and admitted to the isolation WPSAR Vol 13, No 4, 2022 | doi: 10.5365/wpsar.2022.13.4.960https://ojs.wpro.who.int/ 3 Ralstonia outbreak in a haemodialysis unitAranas et al radiobacter, Bacillus spp., Sphingomonas paucimo- bilis, Pseudomonas putida, Pseudomonas stutzeri, Acinetobacter baumannii, Delftia acidovorans, Serratia plymuthica, Aeromonas hydrophila, Aeromonas punc- tata, Klebsiella oxytoca, coagulase-negative staphylo- cocci, Staphylococcus epidermidis, Staphylococcus haemolyticus and Leclercia adecarboxylata (Table 3). The faucet of the reprocessing machine was the only site that was positive for Ralstonia species. Standard and contact infection, prevention and control precautions and disinfection of equipment and the environment were implemented in the haemodi- alysis unit. The unit was monitored for effectiveness of these preventive measures with follow-up environ- mental swabs taken to ensure elimination of the source of infection. The wide range of organisms found in the haemodialysis unit indicates the need for maintaining a thorough general cleaning and regular disinfection protocol to prevent opportunistic infections. Upon the results of the environmental testing, thorough disinfec- tion and general cleaning of the haemodialysis unit was conducted. DISCUSSION Three cases of Ralstonia insidiosa infection were de- tected within the haemodialysis unit and were linked to a contaminated faucet in the haemodialysis reprocessing machine. Upon detection of these cases, haemodialysis sessions were suspended and an investigation com- menced. Environmental evidence determined the source of infection, after which the faucet of the haemodialysis growth of R. insidiosa. Co-trimoxazole 800/160 one tablet daily for 7 days was given for the bacteraemia. The patient recovered from the bacteraemia and was discharged. Antibiotic susceptibility testing Antibiograms of cases 1 and 2 were both resistant to amikacin and gentamicin with sensitivity to most of the other antibiotics tested. Case 2 was also resistant to piperacillin-tazobactam. Case 3 was sensitive or had intermediate results for all antibiotics (Table 2). INVESTIGATION AND CONTROL MEASURES A review of all drugs and devices used for each case from 15 days before the onset of symptoms until the confirmation of Ralstonia bacteraemia was conducted. On 10–15 January 2021, environmental samples were collected from 44 sites throughout the haemodialysis unit, including reprocessing tubing, faucets, suction tubing, suction containers, water sources, venous or arterial site coupling machines and bleach source machines. Samples were also collected from supplies, disinfectants, working areas and devices. All samples were cultured by the hospital’s Department of Pathol- ogy for identification to the genus level only. Sensitivity testing was not conducted as per the hospital protocol for environmental samples. Of the 44 collected samples, 25 were positive for a range of organisms, including: Ralstonia spp., Aeromonas spp., Pseudomonas aeruginosa, Rhizobium Table 1. Clinical characteristics of three cases of Ralstonia bacteraemia detected among chronic kidney disease patients at a single institution in Baguio City, the Philippines, 2020 Characteristics Case 1 Case 2 Case 3 Onset date 9 December 17 December 20 December Age/Sex 70/Male 32/Female 62/Female Comorbidities Chronic kidney disease, hypertension Chronic kidney disease, hypertension Chronic kidney disease, hypertension, diabetes mellitus Haemodialysis access Right internal jugular catheter Right internal jugular catheter Right internal jugular catheter Time on haemodialysis 1 year 1 year 2 months Presenting symptoms Chills Chills, hypotension Disoriented, hypotension, fever Treatment received for bacteraemia Co-trimoxazole 800/160 1 tablet once daily for 7 days Cefepime 500 mg intravenous once daily for 7 days Co-trimoxazole 800/160 1 tablet once daily for 7 days Outcome Discharged Discharged Discharged WPSAR Vol 13, No 4, 2022 | doi: 10.5365/wpsar.2022.13.4.960 https://ojs.wpro.who.int/4 Aranas et alRalstonia outbreak in a haemodialysis unit Table 2. Antibiogram of R. insidiosa isolates in blood cultures in the three clinical cases of Ralstonia bacteraemia detected among chronic kidney disease patients at a single institution in Baguio City, the Philippines, 2020 Table 3. Environmental samples from a haemodialysis unit where Ralstonia bacteraemia was detected among chronic kidney disease patients by site and results at a single institution in Baguio City, the Philippines, 10–15 January 2021 Antimicrobial Case 1 Case 2 Case 3 MIC (μg/mL) Interpretation MIC (μg/mL) Interpretation MIC (μg/mL) Interpretation Amikacin ≥64 R ≥64 R 8 S Cefepime 2 S 4 S ≤1 S Ceftazidime 16 I 16 I ≤1 S Ciprofloxacin ≤0.25 S ≤0.25 S ≤0.25 S Gentamicin ≥16 R ≥16 R 8 I Imipenem 2 S 2 S 2 S Meropenem 4 S 4 S 2 S Piperacillin/Tazobactam 64 I ≥128 R 64 I Trimethoprim/Sulfamethoxazole ≤20 S ≤20 S ≤20 S I: intermediate; MIC: minimum inhibitory concentration; R: resistant; S: sensitive. Sites Growth 1. Faucet, reprocessing machine Ralstonia spp. 2. Reprocessing tubing, station 2 Aeromonas spp. 3. Reprocessing tubing, hep c Pseudomonas aeruginosa 4. Reprocessing tubing, hep b No growth after 48 hours of incubation 5. Water processing machine knobs Rhizobium radiobacter 6. Point of use No growth after 48 hours of incubation 7. Product tank No growth after 48 hours of incubation 8. Acid mixer faucet No growth after 48 hours of incubation 9. Bubbler, station 3 Bacillus spp. 10. Oxygen port, station 20 Sphingomonas paucimobilis 11. Oxygen port, station 18 No growth after 48 hours of incubation 12. Panasonic refrigerator Bacillus spp. 13. Suction tubing 1 No growth after 48 hours of incubation 14. Suction tubing 2 No growth after 48 hours of incubation 15. Suction container 1 Pseudomonas putida 16. Suction container 2 No growth after 48 hours of incubation 17. Suction container 3 No growth after 48 hours of incubation 18. Venous site coupling, machine 30 Pseudomonas stutzeri 19. Arterial site coupling, machine 30 Acinetobacter baumannii 20. Water source, machine 30 No growth after 48 hours of incubation 21. Citro clean, machine 30 No growth after 48 hours of incubation 22. Bleach source, machine 30 No growth after 48 hours of incubation 23. Chair, machine 30 Staphylococcus haemolyticus 24. Venous site coupling, machine 13 No growth after 48 hours of incubation 25. Arterial site coupling, machine 13 No growth after 48 hours of incubation WPSAR Vol 13, No 4, 2022 | doi: 10.5365/wpsar.2022.13.4.960https://ojs.wpro.who.int/ 5 Ralstonia outbreak in a haemodialysis unitAranas et al the Czech Republic, eight cases of central venous cath- eter infections by Ralstonia insidiosa were observed; all isolates from cases had antibiotic sensitivities to beta- lactams and fluoroquinolones and were resistant to ami- noglycosides.9 Two isolates from this study had similar antibiotic sensitivities to fluoroquinolones, sulfonamide and carbapenems and resistance to aminoglycosides. One case’s isolate had antibiotic sensitivity to almost all drug classes with no resistance. In conclusion, three patients with chronic kidney disease who required haemodialysis developed bac- teraemia with R. insidiosa. All three cases had good clinical outcomes after identification of the organism and specific antibiotic treatment. The source of the con- tamination was identified through environmental testing of possible sites within the haemodialysis unit and was determined to be the faucet of the haemodialysis reprocessing machine. Taken with previously published outbreaks of Ralstonia spp., these findings suggest that medical products and devices can be contaminated with these species and should be suspected when cases are detected. Early identification of these cases and the source of infection is required to prevent large outbreaks and to ensure protection of vulnerable populations such as immunosuppressed patients with end-stage renal disease on haemodialysis. reprocessing machine was appropriately disinfected and cleaning of the haemodialysis unit was initiated. No fur- ther cases have been reported, with active surveillance continuing until January 2022. Several other outbreaks have been reported involving contaminated haemodialy- sis water as the source of infection.10,11 The low attack rate of 1.67% suggests that the three cases were more vulnerable to infection; however, most patients who require dialysis have similar disease profiles with additional comorbidities and are of older age. The finding that cases had the same access site of the internal jugular haemodialysis catheter does not con- tribute to increased vulnerability. Right-sided catheters do not relate to increased catheter-related dysfunction and infection. It is therefore possible that they had a greater chance of exposure to the source of infection.12 Treatment for the three cases in this study was 7 days of cefepime and co-trimoxazole only, given ac- cording to the sensitivity of the isolates. In other pub- lished outbreaks, most Ralstonia infections are treated with ciprofloxacin, amikacin piperacillin-tazobactam, meropenem or a combination of aminoglycosides and cephalosporins with a good response.8–10 There are no current standard recommendations for drugs or duration of treatment of Ralstonia bacteraemia. In a report from Sites Growth 26. Water source, machine 13 Delftia acidovorans 27. Bleach source, machine 13 No growth after 48 hours of incubation 28. Citro clean, machine 13 No growth after 48 hours of incubation 29. Oxygen tank, station 4 No growth after 48 hours of incubation 30. E-cart supply box No growth after 48 hours of incubation 31. Oxygen port, station 20 No growth after 48 hours of incubation 32. Water source, pantry Serratia plymuthica 33. Pantry sink, faucet Aeromonas, hydrophila; Aeromonas punctata; Klebsiella oxytoca 34. Water dispenser Bacillus spp. 35. Locker handles Staphylococcus condimenti 36. Telephone Pseudomonas stutzeri 37. Keyboard and mouse, station 2 Coagulase-negative staphylococci 38. Keyboard and mouse, station 1 Coagulase-negative staphylococci 39. Medicine table drawer handle Staphylococcus epidermidis 40. Medicine preparation table Bacillus spp. 41. Main door handle Staphylococcus haemolyticus 42. Dialysis stretcher Pseudomonas stutzeri 43. Weight log Leclercia adecarboxylata 44. Working area Pseudomonas stutzeri WPSAR Vol 13, No 4, 2022 | doi: 10.5365/wpsar.2022.13.4.960 https://ojs.wpro.who.int/6 Aranas et alRalstonia outbreak in a haemodialysis unit 4. Hoefel D, Monis P, Grooby W, Andrews S, Saint C. Profiling bacte- rial survival through a water treatment process and subsequent distribution system. J Appl Microbiol. 2005;99(1):175–86. doi:10.1111/j.1365-2672.2005.02573.x pmid:15960678 5. Ryan MP, Adley CC. The antibiotic susceptibility of water-based bacteria Ralstonia pickettii and Ralstonia insidiosa. J Med Mi- crobiol. 2013;62(7):1025–31. doi:10.1099/jmm.0.054759-0 pmid:23579396 6. Van der Beek D, Magerman K, Bries G, Mewis A, Declercq P, Peeters V, et al. Infection with Ralstonia insidiosa in two patients. Clin Microbiol Newsl. 2005;27(20):159–61. doi:10.1016/j.clin- micnews.2005.09.007 7. Orlíková H, Prattingerová J, Žemličková H, Melicherčíková V, Urban J, Sochorová M. [Bacteremia and sepsis caused by Ral- stonia insidiosa (Ralstonia pickettii-like) in dialysis patients in a Czech hospital in the period January-May 2011]. Zprávy Centra epidemiologie a mikrobiologie. 2011;20(8):290–4. [Czech] 8. Fang Q, Feng Y, Feng P, Wang X, Zong Z. Nosocomial bloodstream infection and the emerging carbapenem-resistant pathogen Ral- stonia insidiosa. BMC Infect Dis. 2019;19(1):334. doi:10.1186/ s12879-019-3985-4 pmid:31014269 9. Vošterová M, Barková J, Šrámek J. Catheter infections caused by Ralstonia insidiosa. Liberec. Czech Republic: Krajská nemocnice Liberec a.s.; 2011. Available from: https://www.edtnaerca.org/ resource/edtna/files/P%20097%20Catheter%20infections%20 caused%20by%20Ralstonia%20Isidios.pdf, accessed 15 Febru- ary 2022. 10. Tejera D, Limongi G, Bertullo M, Cancela M. Ralstonia picket- tii bacteremia in hemodialysis patients: a report of two cases. Rev Bras Ter Intensiva. 2016;28(2):195–8. doi:10.5935/0103- 507x.20160033 pmid:27410414 11. Vincenti S, Quaranta G, De Meo C, Bruno S, Ficarra MG, Carovillano S, et al. Non-fermentative gram-negative bacteria in hospital tap water and water used for haemodialysis and broncho- scope flushing: Prevalence and distribution of antibiotic resistant strains. Sci Total Environ. 2014;499:47–54. doi:10.1016/j.scito- tenv.2014.08.041 pmid:25173861 12. Engstrom BI, Horvath JJ, Stewart JK, Sydnor RH, Miller MJ, Smith TP, et al. Tunneled internal jugular hemodialysis catheters: impact of laterality and tip position on catheter dysfunction and infection rates. J Vasc Interv Radiol. 2013;24(9):1295–302. doi:10.1016/j.jvir.2013.05.035 pmid:23891045 Acknowledgements The authors thank the Infection Prevention and Control Committee of Baguio General Hospital and Medical Center, as well as all the nurses and staff for their support and guidance. Conflicts of interest The authors have no conflicts of interest to declare. Ethics statement Ethics approval was not required for the study because it was observational and anonymized case data were sourced from hospital medical records. Funding This research is a stand-alone project and was financed by the investigators. References 1. Xu Y, Nagy A, Bauchan GR, Xia X, Nou X. Enhanced biofilm forma- tion in dual-species culture of Listeria monocytogenes and Ralsto- nia insidiosa. AIMS Microbiol. 2017;3(4):774–83. doi:10.3934/ microbiol.2017.4.774 pmid:31294188 2. Ryan MP, Adley CC. Ralstonia spp.: emerging global opportunistic pathogens. Eur J Clin Microbiol Infect Dis. 2014;33(3):291–304. doi:10.1007/s10096-013-1975-9 pmid:24057141 3. Ryan MP, Pembroke JT, Adley CC. Genotypic and phenotypic di- versity of Ralstonia pickettii and Ralstonia insidiosa isolates from clinical and environmental sources including high-purity water. Diversity in Ralstonia pickettii. BMC Microbiol. 2011;11(1):194. doi:10.1186/1471-2180-11-194 pmid:21878094 https://www.edtnaerca.org/resource/edtna/files/P%20097%20Catheter%20infections%20caused%20by%20Ralstonia%20Isidios.pdf https://www.edtnaerca.org/resource/edtna/files/P%20097%20Catheter%20infections%20caused%20by%20Ralstonia%20Isidios.pdf https://www.edtnaerca.org/resource/edtna/files/P%20097%20Catheter%20infections%20caused%20by%20Ralstonia%20Isidios.pdf