This article aims to recognise Ralstonia as a rising threat in healthcare settings and understand its diagnostic, therapeutic, and infection control implications. It offers practical insights for managing bloodstream infections in high-risk patients.

The genus includes species such as Ralstonia pickettii and Ralstonia mannitolilytica, which are known for their ability to survive in aqueous environments and contaminate medical devices, solutions, and pharmaceuticals.

Their clinical significance has grown due to outbreaks in healthcare settings, frequently linked to contaminated fluids and equipment [1], [2]. Ralstonia infections present significant challenges for healthcare providers due to their resistance to common antimicrobial agents [3].

Pathogenesis

1. Ralstonia species are environmental organisms with low inherent virulence, yet they can cause significant infections in vulnerable hosts.
2. They are capable of forming biofilms, which facilitate persistence on medical devices such as intravenous catheters and in hospital water systems [4], [5].
3. Their resistance to disinfectants and ability to pass through standard 0.2-micron filters contribute to their role in healthcare-associated infections [4].
4. Once in the bloodstream, Ralstonia may evade host immune responses, especially in patients with compromised immunity or those undergoing invasive procedures [2], [5].

Clinical Presentation

1. Infections caused by Ralstonia most commonly present as bloodstream infections or sepsis, particularly in hospitalised patients. Symptoms may include fever, chills, hypotension, and signs of systemic inflammatory response.
2. Immunocompromised patients, neonates, and those in intensive care units (ICUs) are at greatest risk.
3. The clinical course can range from mild to severe, depending on the host’s underlying condition and the promptness of intervention and management.

Discussion of Cases in Brief

This case series analyses 23 patients diagnosed with Ralstonia bacteremia via blood cultures. The cohort includes both pediatric and adult patients, with a slight male predominance.

Most cases were identified in critical care settings, including the ICU, NICU, and pediatric ICU (PICU). The duration of ICU stay varied widely, with some patients being admitted for over two weeks. The majority were admitted at the time of diagnosis, with only a few being discharged or deceased.

Notably, several patients had prolonged ICU stays (up to 28 days), and a subset required ventilatory support. The presence of comorbidities such as prematurity in neonates, underlying chronic illnesses, and the use of invasive devices was common among those affected [1],[3].

These findings suggest that Ralstonia infections predominantly affect those with significant healthcare exposure and underlying vulnerabilities [5].

Factors Affecting the Pathogen

Several factors contribute to the pathogenicity and persistence of Ralstonia in healthcare settings:

1. Environmental Resilience: Ralstonia can survive in water, saline, and disinfectant solutions [4],[5].
2. Biofilm Formation: This ability enhances survival on medical devices and resistance to cleaning [4].
3. Intrinsic Resistance: They often exhibit partial resistance to commonly used antibiotics [2],[5].
4. Vulnerable Hosts: The highest risks are encountered in neonates, immunocompromised patients, and those with prolonged hospital stays or invasive devices [3].

Diagnostics

1. Diagnosis of Ralstonia infection relies on blood culture and subsequent microbiological identification. Automated blood culture systems may detect the organism, but definitive identification often requires advanced techniques such as MALDI-TOF mass spectrometry or molecular methods [1].
2. Susceptibility testing is essential due to variable resistance patterns noted in different isolates [2], [5].
3. In this case series, all diagnoses were confirmed by automated blood cultures for identification and antibiotic sensitivity testing, underscoring the importance of vigilant microbiological surveillance in high-risk units [4], [2].

Treatment

1. Management of Ralstonia infections involves prompt initiation of appropriate antimicrobial therapy, guided by susceptibility testing [3].
2. This organism often demonstrates resistance to several beta-lactam antibiotics, necessitating the use of alternative agents such as beta-lactam beta-lactamase inhibitor combination, carbapenems, fluoroquinolones or cotrimoxazole in some cases[2].
3. Additionally, removal of contaminated devices and addressing potential sources of infection are critical for achieving successful outcomes [1],[5].
4. Supportive care in the ICU, including hemodynamic support and ventilatory assistance, may be required for severe cases [3].

Disclaimer: The views and opinions expressed in this article are those of the author and do not necessarily reflect the official policy or position of M3 India.

About the author of this article: Dr. Vaidehi Mehta is an MD Microbiology, Professor and Head, Department of Microbiology, Parul Institute of Medical Science and Research, Parul University, Vadodara.