Ralstonia are gram-negative bacillus and rarely causes primary bacteremia and the infection is usually secondary to contaminated medical products, fluids and/or medications. R. picketti (formerly known as Pseudomonas picketti and Burkholderia picketti) is most commonly reported pathogen for sepsis and has been isolated from various clinical specimens like blood, urine and cerebrospinal fluid [4], from water including municipal drinking water supplies [5, 6], bottled water [7], dental water supplies [8, 9], hospital water supplies [10], space shuttle water systems, standard purified water, laboratory based high-purity water systems and industrial Ultra-pure/High Purity water, from plastic industrial water piping, medicine vials [11], contaminated saline solution [12], from respiratory therapy solutions and wound irrigation systems [13], and blood culture bottles [14]. This organism is not considered as a major pathogen and therefore it is not routinely looked for in hospital analysis. Ralstonia is an opportunistic human pathogen and seen in immunocompromised condition, as seen in the present case. The premature neonates are in an immunocompromised state making them prone to develop this infection. The recent studies have shown that Ralstonia is a growing opportunistic pathogen whole over the world [15].
Ralstonia picketti is an inhabitant of environment, is not considered a part of normal human flora and has been reported to cause nosocomial outbreak secondary to contaminated fluids [16]. Their transmission usually requires human contact with heavily contaminated medical devices or substances encountered in the hospital settings. The exact mode of transmission is not known but it likely involves exposure to contaminated medical devices. As R. picketti is one of the uncommon cause of infection in humans, very little is known about associated virulence factors [17].
The microbiological properties show no distinct appearance on blood agar and they are non-lactose fermenter on Mac Conkey Agar. The biochemical properties show variable growth at 42 °C, gas from nitrate and gelatin liquefaction, oxidation of lactose, positive for nitrate reduction, urea hydrolysis, xylose oxidation and glucose oxidation and negative for arginine hydrolysis, Lysine decarboxylase and oxidation of mannitol [4].
The treatment of Ralstonia spp. sepsis is difficult and challenging because this pathogen is resistant to many commonly used antibiotics, like β-lactams and aminoglycosides [18]. In the index case, the pathogen was only sensitive to Tetracycline and Tigecycline. We used Tigecycline, a tetracycline derivative as baby condition was critically sick and when we assessed risk benefit ratio we decided to start Tigecycline and baby improved after the change of antibiotics. There is lack of validated susceptibility testing that poses a substantial risk of erroneous interpretations. There are no definitive guidelines and the reliable therapeutic data is limited as R. picketti is one of the rarely isolated organism from human specimens. Ryan et al. in their study reported that numerous strains of R. picketti and R. insidiosa were highly resistant to the aminoglycoside (gentamicin) and the ß-lactam antibiotic aztreonam and were variably resistant to the Ticarcillin-clavulanic acid. The best antibiotic in the study were sulfamethoxazole/trimethoprim and the fluoroquinolone (ciprofloxacin) [19].
There are no recommended vaccination or prophylaxis protocols for Ralstonia because of the rarity of the infection despite the ubiquity of the organism. Hospital acquired infections can be controlled through the use of appropriate sterile technique and implementation of strict protocols for sterilization and disinfection of hospital supplies [15].
Kimura et al. conducted case–control study to determine risk factors for infection following outbreak of Ralstonia picketti bacteremia in nursery. There were 18 patients with 19 episode of infection and all cases were within 1 month. There was no neonatal death secondary to bacteremia because of low virulence of the bacteria. The source of this outbreak was contaminated heparin flush and the epidemic ended with discontinuation of it [20].
Vitaliti et al. reported a case of neonatal sepsis caused by R. picketti in a 26-week infant. The infant had Ralstonia sepsis at 25 days of postnatal life in form of apnea and bradycardia requiring mechanical ventilation. The infant died secondary to disseminated intravascular coagulation and fatal multiorgan failure [21].
Bonatti et al. reported a case of R. picketti in 29-week preterm infant. The infant had post-hemorrhagic hydrocephalus that was managed with ventriculo–peritoneal shunt system and there was isolation of R. picketti from the cerebrospinal fluid. This infection was thought secondary to the shunt and the preterm was discharged in well condition [22].
Forgie et al. reported a case of neonate who was operated for hypoplastic left heart syndrome at age of six day of postnatal life. The neonate received extracorporeal membrane oxygenation (ECMO) post-operatively and neonate developed R. picketti sepsis secondary to ECMO circuit. The neonate was treated with ciprofloxacin for 14 days and was discharged successfully [23].
Pandey et al. from India reported three case of R. picketti bacteremia in adult intensive care unit. The two patients succumbed to death were case of leukemia and were on immunosuppressive therapy and third case of thalassemia, even though on immunosuppressive medications was discharged successfully [24].
There is need for vigilance over the infection caused by Ralstonia especially in intensive care unit where they are more prone to cause sepsis. The role of routine antibiotic prophylaxis for Ralstonia is not recommended by us as the infection is very rare and widespread use of the antibiotics may lead to multidrug resistance in this organism. The health care person should have extra vigilance of other patients if a single case of Ralstonia is found (e.g. cause could be a contaminated saline solution batch or medicine vial) and should test specifically for R. picketti if multiple cases of sepsis suddenly present. There is recently an increase in the incidence of Ralstonia sepsis and this may be a time for physicians to consider whether changes are required to the current norms in prophylaxis, detection and/or monitoring.
Ralstonia picketti is not recognized as major pathogen and is an uncommon cause of neonatal sepsis. The source of infection is usually contaminated solutions and medical products. The management involves early detection, treatment with appropriate antibiotics and doing surveillance culture of the possible sources to identify the correct source.
