Acquisition of multidrug-resistant Serratia marcescens by critically ill patients who consumed tap water during receipt of oral medication

Outbreak of Invasive Serratia marcescens among Persons Incarcerated in a State Prison, California, USA, March 2020-December 2022

Serratia marcescens is an environmental gram-negative bacterium that causes invasive disease in rare cases. During 2020-2022, an outbreak of 21 invasive Serratia infections occurred in a prison in California, USA. Most (95%) patients had a history of recent injection drug use (IDU). We performed whole-genome sequencing and found isolates from 8 patients and 2 pieces of IDU equipment were closely related. We also identified social interactions among patients. We recovered S. marcescens from multiple environmental samples throughout the prison, including personal containers storing Cell Block 64 (CB64), a quaternary ammonium disinfectant solution. CB64 preparation and storage conditions were suboptimal for S. marcescens disinfection. The outbreak was likely caused by contaminated CB64 and propagated by shared IDU equipment and social connections. Ensuring appropriate preparation, storage, and availability of disinfectants and enacting interventions to counteract disease spread through IDU can reduce risks for invasive Serratia infections in California prisons.

Faucet aerators as a reservoir for Carbapenem-resistant Acinetobacter baumannii: a healthcare-associated infection outbreak in a neurosurgical intensive care unit

Background

On January 7, 2019, we observed an outbreak of healthcare-associated infection (HAI) caused by Carbapenem-resistant Acinetobacter baumannii (CRAB) in the neurosurgical intensive care unit (NSICU). A follow-up epidemiological investigation was conducted, and an emergency response was initiated. We aimed to study the clonal transmission of CRAB and its possible source.

Methods

A matched case-control (1:2) study was performed to identify the possible predisposing factors. A multifaceted intervention was implemented to control the outbreak. We collected environmental samples from patients' rooms and living area of the staff. CRAB isolates were tested for genetic relatedness by Pulsed-Field Gel Electrophoresis (PFGE).

Results

Environmental sampling showed that a faucet aerator was contaminated with A. baumannii. Molecular typing revealed the only outbreak strain, which was isolated from tracheal aspirate cultures of the first case of community-acquired infection and 3 cases of HAI. In environmental samples, the outbreak strain was found only in the faucet aerator of the dining room. This CRAB outbreak was discovered in time, and further progress of this outbreak was prevented through a pre-set emergency response procedure.

Conclusions

The faucet aerator acted as a reservoir for bacteria in the outbreak, and contamination of the faucet aerator might have occurred from splashes originating from handwashing by the healthcare workers (HCWs). In high-risk areas, such as NSICU, the faucet aerators should not be used during an outbreak or they should be regularly cleaned and disinfected. The start-up criteria for the emergency response played a key role in controlling the CRAB outbreak, and its settings should be discussed more widely.

Serratia marcescens osteomyelitis in Cushing's disease

We report a case of a 46-year-old man with fever, hypotension and arthralgias of the ankles and knees after brain surgery for a pituitary tumour causing Cushing's disease. Blood and urine cultures isolated Serratia marcescens; antibiotic susceptibility testing showed sensitivity to piperacillin-tazobactan and ciprofloxacin. Articular MRI showed inflammation and necrosis of both knees and ankles, and left hip and right elbow (compatible with osteomyelitis). Culture of an ankle abscess on the ankle joint was positive for Serratia marcescens. Bone scintigraphy confirmed osteomyelitic lesions. Medical treatment included antibiotics and strong opioid therapy for 14 weeks. The patient was discharged clinically improved maintaining ciprofloxacin for 24 additional weeks based on clinical and analytic recovery.

Aetiology, source and prevention of waterborne healthcare-associated infections: a review

The purpose of this review is to discuss the scientific literature on waterborne healthcare-associated infections (HCAIs) published from 1990 to 2012. The review focuses on aquatic bacteria and describes both outbreaks and single cases in relation to patient characteristics, the settings and contaminated sources. An overview of diagnostic methods and environmental investigations is summarized in order to provide guidance for future case investigations. Lastly, on the basis of the prevention and control measures adopted, information and recommendations are given. A total of 125 reports were included, 41 describing hospitalized children. All cases were sustained by opportunistic pathogens, mainly Legionellaceae, Pseudomonadaceae and Burkholderiaceae. Hot-water distribution systems were the primary source of legionnaires’ disease, bottled water was mainly colonized by Pseudomonaceae, and Burkholderiaceae were the leading cause of distilled and sterile water contamination. The intensive care unit was the most frequently involved setting, but patient characteristics were the main risk factor, independent of the ward. As it is difficult to avoid water contamination by microbes and disinfection treatments may be insufficient to control the risk of infection, a proactive preventive plan should be put in place. Nursing staff should pay special attention to children and immunosuppressed patients in terms of tap-water exposure and also their personal hygiene, and should regularly use sterile water for rinsing/cleaning devices.

Plumbing of hospital premises is a reservoir for opportunistically pathogenic microorganisms: a review

Several bacterial species that are natural inhabitants of potable water distribution system biofilms are opportunistic pathogens important to sensitive patients in healthcare facilities. Waterborne healthcare-associated infections (HAI) may occur during the many uses of potable water in the healthcare environment. Prevention of infection is made more challenging by lack of data on infection rate and gaps in understanding of the ecology, virulence, and infectious dose of these opportunistic pathogens. Some healthcare facilities have been successful in reducing infections by following current water safety guidelines. This review describes several infections, and remediation steps that have been implemented to reduce waterborne HAIs.

[Endemic and epidemic. Investigation of a nosocomial outbreak]

The majority of healthcare associated infections are endemic, but outbreaks or epidemic infections also occur. The most frequent nosocomial endemic infections are catheter associated bacteremia, ventilator-associated pneumonia, surgical site infections and urinary catheter associated infections. These are conditions with a significant healthcare burden. Infection control measures are the mainstay for reducing their frequency and health impact. Other nosocomial infections occur in epidemic outbreaks, with potential and various negative consequences. A well conducted outbreak investigation can achieve good control at an early stage of the development of an outbreak. This research is divided into several stages that facilitate monitoring the development of the work in an orderly and efficiently manner. It also includes some guidelines for writing reports and scientific papers concerning outbreaks.

Serratia infections: from military experiments to current practice

Serratia species, in particular Serratia marcescens, are significant human pathogens. S. marcescens has a long and interesting taxonomic, medical experimentation, military experimentation, and human clinical infection history. The organisms in this genus, particularly S. marcescens, were long thought to be nonpathogenic. Because S. marcescens was thought to be a nonpathogen and is usually red pigmented, the U.S. military conducted experiments that attempted to ascertain the spread of this organism released over large areas. In the process, members of both the public and the military were exposed to S. marcescens, and this was uncovered by the press in the 1970s, leading to U.S. congressional hearings. S. marcescens was found to be a certain human pathogen by the mid-1960s. S. marcescens and S. liquefaciens have been isolated as causative agents of numerous outbreaks and opportunistic infections, and the association of these organisms with point sources such as medical devices and various solutions given to hospitalized patients is striking. Serratia species appear to be common environmental organisms, and this helps to explain the large number of nosocomial infections due to these bacteria. Since many nosocomial infections are caused by multiply antibiotic-resistant strains of S. marcescens, this increases the danger to hospitalized patients, and hospital personnel should be vigilant in preventing nosocomial outbreaks due to this organism. S. marcescens, and probably other species in the genus, carries several antibiotic resistance determinants and is also capable of acquiring resistance genes. S. marcescens and S. liquefaciens are usually identified well in the clinical laboratory, but the other species are rare enough that laboratory technologists may not recognize them. 16S rRNA gene sequencing may enable better identification of some of the less common Serratia species.

Serratia infections in a general hospital: characteristics and outcomes

We aimed to present our experience regarding infections caused by Serratia spp. in a region with relatively high antimicrobial resistance rates. We retrospectively reviewed the databases of the microbiological laboratory of the University Hospital of Heraklion, Crete (2/2004-12/2009). A total of 77 patients [67.5% men, mean age ± standard deviation (SD) = 56.9 ± 24.5 years) were identified; 37.7% were outpatients. Sixty-five (84.4%) of the 77 included patients had a Serratia marcescens isolate; the remaining 12 patients had a non-marcescens Serratia spp. The most frequently observed infections were respiratory tract infection (32.5%) and keratitis/endophthalmitis (20.8%). Seventy-three (94.9%) patients were cured. Four deaths were observed; three of them were considered as attributed to the Serratia infection. No difference was found regarding the characteristics and outcomes between patients with Serratia marcescens and non-marcescens infections. In addition, antipseudomonal penicillins and their combinations with beta-lactamase inhibitors, as well as carbapenemes, and fluoroquinolones exhibited high antimicrobial activity against both the tested Serratia marcescens and non-marcescens isolates. Our study adds useful information regarding the characteristics and outcomes of patients with Serratia infection, as well as the susceptibilities of the respective Serratia marcescens and non-marcescens isolates, in a region with relatively high levels of antimicrobial resistance.

Outbreak of severe sepsis due to contaminated propofol: lessons to learn

Nosocomial infections are a frequent concern in healthcare. Despite the available knowledge on nosocomial infections and preventive measures, outbreaks of infections continue to occur. An outbreak of severe sepsis in patients who underwent minor procedures in an operating theatre during two consecutive days is described and analysed in this study. We performed a retrospective cohort study using epidemiological data in order to investigate the source of infection together with microbiological and on-site investigations and interviews. Seven patients met the case definition of postoperative systemic inflammatory response syndrome (SIRS). All other patients operated on over the same period served as controls. Of the risk factors investigated, general anaesthesia and propofol were statistically significant (P=0.003). Klebsiella pneumoniae and Serratia marcescens were cultured from opened vials of propofol, propofol-related devices and from blood cultures from two of the patients. These strains were genotypically indistinguishable. Lapses in aseptic preparation, handling and storage of the propofol were observed, and were the most probable cause of the extrinsic contamination. The daily procedure of handling propofol was not performed according to the manufacturer's recommendations, the main departure being the use of a single-use vial for multiple patients. This study documents the risk of infection due to contaminated propofol and the importance of having written guidelines for its handling.

Outbreak of Serratia marcescens in a neonatal intensive care unit: contaminated unmedicated liquid soap and risk factors

This study describes an outbreak of Serratia marcescens and its investigation and control in a neonatal intensive care unit (NICU). During a three-month period, five infants were colonised or infected by a single strain of S. marcescens. A case-control study, culture surveys and pulse-field gel electrophoresis analysis implicated a bottle soap dispenser as a reservoir of S. marcescens (P=0.032). Infants with S. marcescens colonisation or infection were also more likely to have been exposed to a central or percutaneous venous catheter (P=0.05) and had had longer exposure to endotracheal intubation (P=0.05). Soap dispensers are used in many hospitals and may be an unrecognised source of nosocomial infections. This potential source of infection could be reduced by using 'airless' dispensers which have no air intake for the distribution of soap. Prompt intervention and strict adherence to alcoholic hand disinfection were the key factors that led to the successful control of this outbreak.

Outbreak of Serratia marcescens bloodstream and central nervous system infections after interventional pain management procedures

OBJECTIVES

To determine the cause of an outbreak of Serratia marcescens infections in patients after interventional pain management procedures at an outpatient pain clinic.

METHODS

We conducted a case-control study and collected clinical and environmental samples.

RESULTS

We identified 5 culture-confirmed case-patients and 2 presumptive case-patients who had no bacteria recovered from cultures. The 7 case-patients were compared with 28 controls who underwent procedures at the same clinic but did not develop symptoms of infection. All confirmed case-patients had S. marcescens bloodstream infections; 2 had concurrent S. marcescens central nervous system infections. Case-patients were more likely than controls to have procedures that used contrast solution or entered the epidural or intervertebral disc space (P< or =0.01 for each). All S. marcescens clinical isolates were indistinguishable by pulsed-field gel electrophoresis. We did not isolate S. marcescens from medications or environmental samples; however, S. marcescens was shown to survive and grow in contrast solution that was experimentally contaminated for up to 30 days. Single-dose vials of medication, including contrast solution, were used for multiple procedures; multiple medications were accessed with a common needle and syringe.

DISCUSSION

The findings of this investigation suggest contamination of a common medication, likely contrast solution, as the source of the outbreak. Practices, such as reusing single-dose medication vials and using a common needle and syringe to access multiple medications, could have led to contamination and propagation of S. marcescens and should be avoided in interventional pain management procedures.

Population-based laboratory surveillance for Serratia species isolates in a large Canadian health region

A population-based laboratory surveillance was conducted during a six-year period to define the incidence, demographic risk factors for acquisition, and anti-microbial susceptibilities of Serratia species isolates. A total of 715 incident Serratia species isolates were identified for an annual incidence of 10.8 per 100,000 residents; bacteremic disease occurred in 0.9 per 100,000 residents annually. The incidence increased with advancing age and males were at the highest risk. Ninety-two percent of the isolates were Serratia marcescens, and the majority (65%) of incident Serratia species isolates were of community onset. Ninety-five percent of isolates were susceptible to ciprofloxacin, 98% to gentamicin, 98% to trimethoprim/sulfamethoxazole, and >99% to imipenem. No yearly increase in resistance was observed. Serratia species isolation is most commonly of community onset and older patients and males are at increased risk. Despite reports of increasing resistance among Serratia species, the incidence in our region remains at a low stable rate.