Impact of Whole Genome Sequencing to investigate transmission of Serratia marcescens in Neonatal Intensive Care Unit.

Newborns admitted to neonatal intensive care units (NICU) are at increased risk of health care-associated infections. Serratia marcescens represent the third most common pathogen in NICU outbreaks. Here we present an outbreak investigation performed using Whole Genome Sequencing (WGS) analyses and the control measures implemented to limit the spread of S. marcescens in the NICU of an Italian hospital. In February 2023 S. marcescens was isolated from six newborns, when in 2022 this pathogen was isolated only from two samples in the same ward. Measures for infection prevention were adopted. Routinary surveillance screening, performed with rectal swabs collected at admission and weekly thereafter, was implemented to search for S. marcescens presence. Environmental samples were collected. All the isolates, obtained from the conjunctival swab of six newborns, from rectal swab of two newborns who did not develop infections, as well as from the aerators of two faucets, were sequenced. WGS analyses showed no correlation between the isolates from newborns and environmental isolates. The implementation of the measures for infection prevention and control had enabled us to successfully control the outbreak within a short period. WGS analyses proved to be crucial in outbreak investigation to limit the spreading of the pathogens.

Serratia marcescens-associated subcutaneous abscess in a dog.

This report describes the clinical presentation and progression of a Serratia marcescens-associated subcutaneous abscess in a dog with hypothyroidism, hyperadrenocorticism and diabetes mellitus. The S. marcescens isolate was resistant to several antibiotics. Treatment with antibiotics and topical antiseptics was not successful.

Implementation of a PCR-based strategy to control an outbreak by Serratia marcescens in a Neonatal Intensive Care Unit.

OBJECTIVES: To evaluate the clinical and epidemiological impact of a new molecular surveillance strategy based on qPCR to control an outbreak by Serratia marcescens in a Neonatal Intensive Care Unit (NICU). METHODS: We design a specific qPCR for the detection of S. marcescens in rectal swabs of patients admitted to a NICU. We divided the surveillance study into two periods: (a) the pre-PCR, from the outbreak declaration to the qPCR introduction, and (b) the PCR period, from the introduction of the qPCR until the outbreak was solved. In all cases, S. marcescens isolates were recovered and their clonal relationship was analysed by PFGE. Control measures were implemented during the outbreak. Finally, the number of bloodstream infections (BSI) was investigated in order to evaluate the clinical impact of this molecular strategy. RESULTS: Nineteen patients colonized/infected by S. marcescens were detected in the pre-PCR period (October 2020-April 2021). On the contrary, after the PCR implementation, 16 new patients were detected. The PFGE revealed 24 different pulsotypes belonging to 7 different clonal groups, that were not overlapping at the same time. Regarding the clinical impact, 18 months after the qPCR implementation, no more outbreaks by S. marcescens have been declared in the NICU of our hospital, and only 1 episode of BSI has occurred, compared with 11 BSI episodes declared previously to the outbreak control. CONCLUSIONS: The implementation of this qPCR strategy has proved to be a useful tool to control the nosocomial spread of S. marcescens in the NICU.

Serratia marcescens Endocarditis.

Severe infections due to Serratia marcescens have been documented with increasing frequency in persons who inject drugs and are frequently associated with nosocomial outbreaks. S marcescens endocarditis is rare, and there are very few, if any, reported cases secondary to an infected wound acquired at home. We present such a case in an immunocompetent 50-year-old man with paraplegia for 30 years and chronic decubitus ulcers who likely contracted the rare opportunistic Serratia following sacral wound contact with unclean surfaces in his hotel room bathroom. While it is also possible that the organism was obtained during a hospital admission 2 months before the positive blood cultures, he was found sitting with his ulcer in direct contact with red-pigmented accumulations on the shower floor. Therefore, it is more likely that he acquired the infection outside of the hospital setting. Early and effective management with advanced cardiac techniques and appropriate antibiotic coverage resulted in a positive outcome.

Serratia marcescens Necrotizing Fasciitis of the Ankle: A Case Report.

Necrotizing fasciitis is a devastating inflammatory infection requiring emergent medical treatment and surgical intervention. Even with timely management, the mortality rate of necrotizing fasciitis approaches 25%. The causative bacteria invade fascial planes and express toxins that advance rapidly. Here, we document a rare case of necrotizing fasciitis from Serratia marcescens infection. Serratia marcescens is capable of inducing a necrotizing inflammatory cascade mediated by extracellular cytotoxin and lipase. In this case report, a 90-year-old man presented to our emergency department from a long-term care facility with a relatively benign-appearing ulcer with surrounding cellulitis on the right ankle. Blood cultures and wound cultures confirmed the organism to be S marcescens. A multidisciplinary team was consulted for management. The patient received antibiotic therapy and medical support, but because of his comorbid conditions and social situation, the designated medical decision maker opted for comfort care rather than aggressive surgical debridement. The patient progressed through the clinical stages of necrotizing fasciitis. Within 36 hours, the patient died as result of sepsis-induced organ failure.

Validation of a New PCR-Based Screening Method for Prevention of Serratia marcescens Outbreaks in the Neonatal Intensive Care Unit.

BACKGROUND: Serratia marcescens may cause severe nosocomial infections, mostly in very low birth weight infants. Since S. marcescens exhibits by far the highest adjusted incidence rate for horizontal transmission, it can cause complex outbreak situations in neonatal intensive care units. OBJECTIVE: The aim of this study was to establish a fast and highly sensitive colonization screening for prompt cohorting and barrier nursing strategies. METHODS: A probe-based duplex PCR assay targeting the 16S rRNA gene of S. marcescens was developed and validated by using 36 reference strains, 14 S. marcescens outbreak- and nonoutbreak isolates, defined by epidemiological linkage and molecular typing, and applied in 1,347 clinical specimens from 505 patients. RESULTS AND CONCLUSIONS: The novel PCR assay proved to be highly specific and had an in vitro sensitivity of 100 gene copies per reaction (∼15 bacteria). It showed a similar (in laryngeal/tracheal specimens) or even higher (in rectal/stoma swabs) in vivo sensitivity in comparison to routine microbial culture and was much quicker (<24 h vs. 2 days). By combining different oligonucleotide primers, there was robust detection of genetic variants of S. marcescens strains. PCR inhibition was low (1.6%) and observed with rectal swabs only. Cohort analysis illustrated applicability of the PCR assay as a quick tool to prevent outbreak scenarios by allowing rapid decisions on cohorting and barrier nursing. In summary, this novel molecular screening for colonization by S. marcescens is specific, highly sensitive, and substantially accelerates detection.

A rare occurrence of Serratia rubidaea in a patient with ear discharge.

Serratia species are not as frequent as with more virulent members of the Enterobacteriaceae. However, when infections do arise, they are largely associated with Serratia marcescens. Presently, about 10 species of Serratia are recognized and infections caused by the remaining Serratia species are seldom recorded in literature, as they are not often isolated from clinical specimens. This is a case report of Serratia rubidaea isolated from ear discharge of a 35-year old female patient with no co-morbidities and with known history of chronic otomastoiditis for which the patient had undergone left modified radical mastoidectomy. Isolation of this bacterium from clinical specimens is rare; however, it can be an etiological agent for infections in patients who have undergone invasive procedures. The patient was managed with antibiotics and on otoendoscopy at follow-up, no discharge was observed.

Serratia Marcescens Endophthalmitis and Bacteraemia following Complicated Cataract Surgery.

A 93-year-old male presented with left eye pain, fever and loss of vision two days after complicated cataract surgery. A diagnosis of Serratia marcescens endophthalmitis and systemic bacteremia was made after the organism was identified on vitreous and peripheral blood cultures. This case demonstrates that an aggressive intraocular infection can lead to bacteremia.

The First Case Report of Endocarditis Caused by Serratia fonticola.

The cases of human infections caused by Serratia fonticola are relatively rare. The few cases that have been reported primarily describe skin and soft tissue, urinary, and biliary tract infections. We describe a case of a 59-year-old man with infected bilateral lower extremity wounds who developed endocarditis due to S fonticola confirmed with transesophageal echocardiogram. The patient was treated with 6 weeks of antibiotic therapy and had an uneventful recovery. After a thorough review of the literature using PubMed and Google Scholar, we concluded that this is the first reported case of endocarditis caused by S fonticola.

Evaluation of CHROMagar™-Serratia agar, a new chromogenic medium for the detection and isolation of Serratia marcescens.

A comparative analysis of the performance of the new selective chromogenic CHROMagar™-Serratia culture medium for detection and isolation of Serratia marcescens was undertaken. A total of 134 clinical isolates (95 S. marcescens with and without carbapenemase production and 39 non-S. marcescens isolates) and 96 epidemiological samples (46 rectal swabs and 50 from environmental surfaces) were studied. Diagnostic values when compared with CHROMagar™-Orientation medium were 96.8% sensitivity, 100% specificity, 100% positive predictive value and 88.5% negative predictive value. In conclusion, CHROMagar™-Serratia shows an excellent ability for differentiation of S. marcescens among clinical isolates and in environmental samples.

Serrating through vascular access catheters: a great masquerader with severe systemic manifestations.

Serratia marcescens, time and again, has demonstrated its ability to easily adhere and infect vascular access catheters, making them a bona fide source of hospital outbreaks and contributing to adverse patient outcomes. We present a unique case of a severe recurrent Serratia infection, leading to persistent bacteria in the blood, haematogenous dissemination and subsequent development of abscesses, to a degree not reported in the literature before. These infections are exceedingly challenging to eradicate, owing to multiple virulence mechanisms and the deep seeding ability of this microorganism. Serratia infections require a multifaceted approach with intricacies in identification, therapeutics and surveillance, all of which are sparsely reported in the literature and reviewed in this report.

Infection of the hip joint by Serratia marcescens.

A 72-year-old male patient presented to the hospital because of sudden inability to bear weight and without a history of trauma. A fracture of the head of the femur was identified on CT scan of the pelvis. In his history, the patient had a hospital admission 3 months earlier, during which he had a urinary catheter, and a urine specimen was analysed. The same pathogen was found in the patient urine and in the head of the femur specimen. This is a report of blood-borne spread of Serratia marcescens infection from the urothelium to the hip joint, responsible for spontaneous fracture of the femoral head without history of trauma.

Serratia marcescens Infection-Associated Loss of Vision: A Case Report in a Patient with a History of Intravenous Drug Use.

BACKGROUND Serratia marcescens infections have historic association with injection drug use. The present report is about a 53-year-old man with a history of intravenous (IV) drug use who presented with acute loss of vision due to endophthalmitis associated with disseminated S. marcescens infection. CASE REPORT A 53-year-old man with a history of active illicit IV drug use presented with a chief complaint of loss of vision in his left eye for 5 days. He also reported having a fever, chills, and shortness of breath. While in the Emergency Department, he became hypotensive and hypoxic. He needed to be intubated and was started on vasopressor support. An ophthalmological examination was suspicious for endophthalmitis. The patient underwent a vitreous tap with injection of intravitreal antibiotics on the day of admission. An echocardiogram showed severe tricuspid endocarditis requiring valve replacement. He also was found to have a left lung/pleural abscess, which was surgically drained. Later, a left eye vitrectomy was performed and the intravitreal antibiotics were repeated; the treatment was unsuccessful and enucleation eventually was required. In addition, the patient had gastric bleeding and underwent esophagogastroduodenoscopy, which showed ischemic stomach ulcers suggestive of septic emboli. Cultures of the patient's blood, tricuspid valve, lung abscess, and vitreous fluid revealed S. marcescens. He was treated long term with a 2-drug antibiotic regimen and discharged in stable condition. CONCLUSIONS We have presented a rare case of acute loss of vision due to endophthalmitis in a patient with a history of IV drug use, which was associated with disseminated infection with the Gram-negative saprophyte S. marcescens.

Lytic lesion of skull: a rare presentation of chronic granulomatous disease.

An 18-month-old boy presented with lytic lesion of skull and recurrent abscesses with Serratia marcescens The extensive work up revealed a gene mutation confirming the diagnosis of chronic granulomatous disease (CGD). This case scenario underscores the importance of exploring the possibility of immunodeficiency if there is a history of recurrent abscesses with atypical organism. The case also demonstrates that CGD can present as lytic lesion of skull.

Late-onset Subconjunctival Abscess Secondary to Serratia marcescens Associated With Unexposed Ahmed Glaucoma Valve Implant.

PURPOSE: The purpose of this study was to report a rare case of late-onset subconjunctival abscess associated with an unexposed Ahmed glaucoma valve implant secondary to Serratia marcescens, a rare conjunctival pathogen. METHODS: Case description including clinical imaging and literature review of glaucoma drainage device (GDD)-related infections. CASE PRESENTATION: A 73-year-old man presented with blurring of vision, redness, and pain on his right eye 2 months after Ahmed glaucoma valve implantation for advanced postpenetrating-keratoplasty glaucoma. The patient was nonsmoker, had fairly controlled type 2 diabetes mellitus on insulin, and had undergone multiple eye surgeries on the right eye. On ocular examination, the conjunctiva was injected with fairly delineated yellowish-white subconjunctival material in the superotemporal quadrant with no associated tube exposure or leak, and the anterior chamber was quiet. The patient was assessed with Ahmed glaucoma valve infection with subconjunctival abscess and was treated by Ahmed glaucoma valve explant with directed systemic and topical antimicrobial therapy. The culture and sensitivity results revealed S. marcescens sensitive to ciprofloxacin, ceftazidime, gentamicin, and amikacin. Despite the virulence of the pathogen, the eye was saved. CONCLUSIONS: Ahmed glaucoma valve infection with subconjunctival abscess secondary to S. marcescens is rare. GDD-related infections should be suspected in patients presenting with blurring of vision, pain, and redness even in the absence of tube exposure. Early diagnosis and treatment with culture-guided antimicrobial therapy combined with GDD explant is fundamental in optimizing the visual outcome.