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Brodie's abscess is a subacute or chronic osteomyelitis characterised by an intraosseous abscess. It may present months to years after the inciting event. Staphylococcus aureus is the most common causative organism of Brodie's abscess, while Gram-negative bacteria are uncommon causative organisms. A combination of culture-directed antibiotics and surgical debridement is key to successful management. This case report describes a patient with a history of minor trauma preceding the development of Brodie's abscess of the calcaneus caused by Serratia marcescens This was managed successfully with surgical debridement, followed by oral antibiotics., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

Objective: The primary goal of this study was to establish the current microbial trends in vertebral osteomyelitis/discitis (VOD) amid the opioid epidemic and to determine if intravenous drug use (IVDU) predisposes one to a unique microbial profile of infection., Methods: The authors performed a retrospective cohort study consisting of 1175 adult patients diagnosed with VOD between 2011 and 2022 at a single quaternary center. Data were acquired through retrospective chart review, with pertinent demographic and clinical information collected., Results: Staphylococcus aureus was the most cultured organism in both the IVDU and non-IVDU groups at 56.1% and 40.7%, respectively. In the IVDU cohort, Serratia marcescens was the next most prevalently cultured organism at 13.9%., Conclusions: The present study demonstrates that in the IVDU population S. marcescens is an organism of high concern. The potential for Serratia spp. infection should be accounted for when selecting empirical antimicrobial therapy in VOD patients.

The occurrence and transmission of carbapenemase-producing-Enterobacterales (CPE) on a global scale has become a major issue. Clinical reports are rarely providing information on the genomic and plasmid features of carbapenem-resistant Serratia marcescens . Our objective was to investigate the resistance and transmission dynamics of two carbapenem-resistant S. marcescens that are resistant to carbapenem and have caused bacteremia in China. Blood specimens were taken from two individuals with bacteremia. Multiplex PCR was employed to identify genes that code for carbapenemase. Antimicrobial susceptibility tests and plasmid analysis were conducted on S. marcescens isolates SM768 and SM4145. The genome of SM768 and SM4145 were completely sequenced using NovaSeq 6000-PE150 and PacBio RS II platforms. Antimicrobial resistance genes (ARGs) were predicted using the ResFinder tool. S1 nuclease pulsed-field gel electrophoresis (S1-PFGE) and southern blotting were employed to analyze plasmids. Two S. marcescens that produced KPC-2 were identified from bloodstream infections. The antimicrobial susceptibility testing demonstrated that both of the isolates had a resistance to various antibiotics. The whole-genome sequence (WGS) and plasmid analysis revealed the presence of bla KPC-2 -bearing IncR plasmids and multiple plasmid-borne antimicrobial resistance genes in the isolates. Our comparative plasmid analysis suggested that the two IncR plasmids identified in this study could be derived from a common ancestor. Our findings revealed the emergence of bla KPC-2 -bearing IncR plasmid in China, which could be a hindrance to the transmission of KPC-2-producing S. marcescens in clinical settings., Competing Interests: The authors declare that the research was conducted without any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Jia, Huang, Zhang, Sheng, Chu, Xu and Xu.)

Serratia marcescens is a ubiquitous bacterium from order Enterobacterales displaying a high genetic plasticity that allows it to adapt and persist in multiple niches including soil, water, plants, and nosocomial environments. Recently, S. marcescens has gained attention as an emerging pathogen worldwide, provoking infections and outbreaks in debilitated individuals, particularly newborns and patients in intensive care units. S. marcescens isolates recovered from clinical settings are frequently described as multidrug resistant. High levels of antibiotic resistance across Serratia species are a consequence of the combined activity of intrinsic, acquired, and adaptive resistance elements. In this review, we will discuss recent advances in the understanding of mechanisms guiding resistance in this opportunistic pathogen., Competing Interests: The authors declare there are no competing interests., (©2022 Tavares-Carreon et al.)

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., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

The bacterium Serratia marcescens can cause opportunistic infections in humans and in animals. In veterinary settings, the diversity, reservoirs and modes of transmission of this pathogen are poorly understood. The phenotypes and genotypes of Serratia spp. isolated from dogs, cats, horses, a bird and a rabbit examined at an Australian veterinary hospital between 2008 and 2019 were characterised. The isolates were identified as S. marcescens (n = 15) or S. ureilytica (n = 3) and were placed into four distinct phylogenetic groups. Nine quasi-clonal isolates associated with post-surgical complications in different patients displayed high levels of resistance to the antimicrobials fluoroquinolones, cephalosporins, aminoglycosides, and to the disinfectant chlorhexidine. A Serratia sp. with a similar resistance profile was also isolated from chlorhexidine solutions used across the Hospital, suggesting that these infections had a nosocomial origin. A genomic island encoding a homolog of the Pseudomonas MexCD-OprJ biocide efflux system was detected in the chlorhexidine-tolerant Serratia. The nine multi-drug resistant Serratia isolates also possessed a Ser-83-Ile mutation in GyrA conferring fluoroquinolone resistance, and carried a large IncHI2 conjugative plasmid encoding antimicrobial and heavy metal resistances. This replicon was highly similar to a plasmid previously detected in a strain of Enterobacter hormaechei recovered from the Hospital environment. IncHI2 plasmids are commonly found in Enterobacteriaceae, but are rarely present in Serratia spp., suggesting that this plasmid was acquired from another organism. A chlorhexidine-tolerant Serratia isolate which lacked the IncHI2 plasmid was used in mating experiments to demonstrate the transfer of multi-drug resistance from a E. hormaechei donor. This study illustrates the importance of environmental surveillance of biocide-resistance in veterinary hospitals., Competing Interests: The authors have declared that no competing interests exist.

The newer beta-lactam-inhibitor combination (BLIC) antibiotics are available in South Africa (SA) for the treatment of carbapenem-resistant Enterobacterales infections. We describe the successful use of ceftazidime-avibactam (CA) for the treatment of a child with persistent carbapenem-resistant Serratia marcescens bacteraemia, and the challenges faced using this lifesaving antibiotic, including access to susceptibility testing, procurement process, cost and complexity of deciding when, how and for how long to use it. Furthermore, the burden of carbapenem resistance is increasing in SA, and inappropriate use of CA and other newer BLIC antibiotics, such as ceftolozane-tazobactam, will inevitably endanger their longevity. A careful balance must be struck between removing unnecessary obstacles and delays in initiating these antibiotics for life-threatening infections, and additional antimicrobial stewardship-guided interventions aimed at preserving their therapeutic use.

Background: Serratia marcescens becomes an apparent nosocomial pathogen and causes a variety of infections. S. marcescens possess various virulence factors that are regulated by intercellular communication system quorum sensing (QS). Targeting bacterial virulence is a proposed strategy to overcome bacterial resistance. Sitagliptin anti-QS activity has been demonstrated previously and we aimed in this study to investigate the effects of antidiabetic drugs vildagliptin and metformin compared to sitagliptin on S. marcescens pathogenesis., Methods: We assessed the effects of tested drugs in subinhibitory concentrations phenotypically on the virulence factors and genotypically on the virulence encoding genes' expressions. The protection of tested drugs on S. marcescens pathogenesis was performed in vivo. Molecular docking study has been conducted to evaluate the interference capabilities of tested drugs to the SmaR QS receptor., Results: Vildagliptin reduced the expression of virulence encoding genes but did not show in vitro or in vivo anti-virulence activities. Metformin reduced the expression of virulence encoding genes and inhibited bacterial virulence in vitro but did not show in vivo protection. Sitagliptin significantly inhibited virulence factors in vitro, reduced the expression of virulence factors and protected mice from S. marcescens. Docking study revealed that sitagliptin is more active than metformin and fully binds to SmaR receptor, whereas vildagliptin had single interaction to SmaR., Conclusion: The downregulation of virulence genes was not enough to show anti-virulence activities. Hindering of QS receptors may play a crucial role in diminishing bacterial virulence.

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., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2021. No commercial re-use. See rights and permissions. Published by BMJ.)

Serratia marcescens is an emerging opportunistic bacterium that can cause healthcare-associated infections. The high rate of multidrug resistance and the ability to produce a set of virulence factors, by which it can produce infectious diseases makes it urgent to find an alternative approach to the treatment of such infections. Disarming of virulence by targeting of quorum sensing (QS) as the regulating mechanism of virulence is a promising approach that has no effect on bacterial growth that is considered a key factor in emergence of resistance. This study was designed to investigate the ability of sub-inhibitory concentrations (sub-MICs) of sotolon to attenuate virulence of a clinical isolate of S. marcescens. Sotolon at 25 and 50 μg/ml inhibited 35.2 and 47.5% of biofilm formation, respectively. The inhibition of swimming motility were 41.4 and 69.3%, while that of swarming motility were 77.6 and 86.8% at 25 and 50 µg/ml, respectively. Moreover, sotolon reduced prodigiosin production by 76.6 and 87.6% at concentrations of 25 and 50 µg/ml, respectively. Protease activity was reduced by 25 µg/ml of sotolon by 54.8% and was completely blocked at 50 µg/ml. The relative expression of genes regulating virulence factors decreased by 40% for fimA, 29% for fimC, 59% for flhC, 57% for flhD, 39% for bsmB, 37% for rssB, 49% for rsmA, 54% for pigP, and 62% for shlA gene in the presence of 50 µg/ml sotolon. In conclusion, sotolon is an anti-virulence agent that could be used for the treatment of S.marcescens hospital-acquired infections.

Background: Serratia marcescens is a well-known cause of nosocomial infectious outbreaks in the neonatal intensive care unit, with a high mortality rate in the vulnerable preterm population. However, it is not typically associated with neonatal sepsis secondary to intrapartum vertical transmission. We present the case of a preterm male born at 25 weeks and 4 days of gestation in Okinawa, Japan with culture-proven S. marcescens chorioamnionitis and sepsis, as well as a review of the previously published literature., Methods: We conducted a literature search utilizing MeSH indexing with the headings [chorioamnionitis], [Serratia], and [infant, newborn] limited to "humans" with a publication date range between 1950 and 2020., Results: All reported cases of preterm S. marcescens chorioamnionitis occurred in coastal locations. The majority of cases resulted in spontaneous abortion, and we found no published reports of confirmed S. marcescens chorioamnionitis in conjunction with viable preterm delivery and positive neonatal cultures. In the case presented herein, S. marcescens chorioamnionitis with associated neonatal sepsis was confirmed by positive placental and blood cultures. Bacterial clearance was achieved following an antibiotic course consisting of 5 days of gentamicin and 14 days of meropenem therapy., Conclusions: S. marcescens is an uncommon cause of chorioamnionitis that can have devastating neonatal consequences, especially in the at-risk preterm population., Competing Interests: The authors have no funding or conflicts of interest to disclose., (Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.)

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 .

Background: Antibiotic-resistant members of the family Enterobacteriaceae are among the serious threats to human health globally. This study reports the anti-pathogenic activity of Punica granatum peel extract (PGPE) against a multi-drug resistant, beta-lactamase producing member of this family i.e. Serratia marcescens., Objective: This study aimed at assessing the anti-pathogenic activity of PGPE against the gramnegative bacterial pathogen S. marcescens and identifying the molecular targets of this extract in the test bacterium., Methods: Effect of PGPE on S. marcescens growth and quorum sensing (QS)-regulated pigment production was assessed through broth dilution assay. In vivo anti-infective and prophylactic activity of PGPE was assessed employing the nematode worm Caenorhabditis elegans as a model host. Differential gene expression in PGPE-exposed S. marcescens was studied through a whole transcriptome approach., Results: PGPE was able to modulate QS-regulated pigment production in S. marcescens without exerting any heavy growth-inhibitory effect at concentrations as low as ≥2.5 μg/mL. It could attenuate the virulence of the test bacterium towards the worm host by 22-42% (p≤0.01) at even lower concentrations (≥0.5 μg/mL). PGPE also exerted a post-extract effect on S. marcescens. This extract was found to offer prophylactic benefit too, to the host worm, as PGPE-pre-fed worms scored better (34-51%; p≤0.001) survival in face of subsequent bacterial attack. Differential gene expression analysis revealed that PGPE affected the expression of a total of 66 genes in S. marcescens by ≥1.5 fold., Conclusion: The anti-virulence effect of PGPE against S. marcescens is multifaceted, affecting stress-response machinery, efflux activity, iron homeostasis, and cellular energetics of this bacterium notably. Among the major molecular targets identified in this study are LPS export transporter permease (LptF), t-RNA pseudouridine synthase (TruB), etc., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Antibiotic resistance amongst microbial pathogens is a mounting serious issue in researchers and physicians. Various alternatives to overcome the multidrug-resistant bacterial infections are under search, and biofilm growth inhibition is one of them. In this investigation, a polymeric drug delivery system loaded with multi-serratial drugs to improve the delivery of drugs against urinary tract infection causative Serratia marcescens . The chitosan grafted pyromellitic dianhydride - cysteine (CS-g-PMDA-CYS) was conjugated with AuNPs by using the -SH group of CYS and RF (rifampicin) and INH (isoniazid) were loaded in AuNPs-fused CS-g-PMDA-CYS system. Several physicochemical techniques characterized this fabricated AuNPs/RF/INH/CS-g-PMDA-CYS system. The successful encapsulation of RF and INH in AuNPs-fused CS-g-PMDA-CYS polymer had confirmed, and it observed the loading capacity for RF and INH was 9.02% and 13.12%, respectively. The in vitro drug discharge pattern was perceived high in pH 5.5 compared with pH 7.4. The AuNPs/RF/INH/CS-g-PMDA-CYS escalates 74% of Caenorhabditis elegans survival during Serratia marcescens infection by aiming biofilm development and virulence in S. marcescens . Author postulate that the fabricated system is a promising drug carrier and delivery system for inhibition of multidrug-resistant bacterias like S. marcescens .

Multidrug resistance prompts the search for new sources of antibiotics with new targets at bacteria cell. To investigate the antibacterial activity of Cinnamomum cassia L. essential oil (CCeo) alone and in combination with antibiotics against carbapenemase-producing Klebsiella pneumoniae and Serratia marcescens. The antimicrobial susceptibility of the strains was determined by Vitek® 2 and confirmed by MALDI-TOF/TOF. The antibacterial activity of CCeo and its synergism with antibiotics was determined using agar disk diffusion, broth microdilution, time-kill, and checkboard methods. The integrity of the bacterial cell membrane in S. marcescens was monitored by protein leakage assay. CCeo exhibited inhibitory effects with MIC = 281.25 μg.mL-1. The association between CCeo and polymyxin B showed a decrease in terms of viable cell counts on survival curves over time after a 4 hour-treatment with a FIC index value of 0.006. Protein leakage was observed with increasing concentrations for CCeo and CCeo + polymyxin B treatments. CCeo showed antibacterial activity against the studied strains. When associated with polymyxin B, a synergistic effect was able to inhibit bacterial growth rapidly and consistently, making it a potential candidate for the development of an alternative treatment and drug delivery system for carbapenemase-producing strains., Competing Interests: The authors have declared that no competing interests exist.

Background: Serratia marcescens is an emerging pathogen that causes a variety of health care associated infections. S. marcescens is equipped with an arsenal of virulence factors such as biofilm formation, swimming and swarming motilities, prodigiosin, protease and others which enable it to initiate and cause the infection. These virulence factors are orchestrated under the umbrella of an intercellular communication system named Quorum sensing (QS). QS allows bacterial population to synchronize the expression of virulence genes upon detection of a chemical signaling molecule. Targeting bacterial virulence is a promising approach to attenuate bacteria and enhances the ability of immune system to eradicate the bacterial infection. Drug repurposing is an advantageous strategy that confers new applications for drugs outside the scope of their original medical use. This promising strategy offers the use of safe approved compounds, which potentially lowers the costs and shortens the time than that needed for development of new drugs. Sitagliptin is dipeptidyl peptidase-4 (DPP-4) inhibitor, is used to treat diabetes mellitus type II as it increases the production of insulin and decreasing the production of glucagon by the pancreas. We aimed in this study to repurpose sitagliptin, investigating the anti-virulence activities of sitagliptin on S. marcescens., Methods: The effect of sub-inhibitory concentrations of sitagliptin on virulence factors; protease, prodigiosin, biofilm formation, swimming and swarming motilities was estimated phenotypically. The qRT-PCR was used to show the effect of sitagliptin on the expression of QS-regulated virulence genes. The in-vivo protective activity of sitagliptin on S. marcescens pathogenesis was evaluated on mice., Results: Sitagliptin (1 mg/ml) significantly reduced the biofilm formation, swimming and swarming motilities, prodigiosin and protease. The qRT-PCR confirmed the effect on virulence as shown by down regulating the expression of fimA, fimC, flhC, flhD, bsmB, rssB, rsmA, pigP, and shlA genes. Moreover, the in-vivo findings showed the efficient ability of sitagliptin to weaken S. marcescens pathogenesis., Conclusion: Sitagliptin is a promising anti-virulence agent against S. marcescens that may be beneficial in the control of healthcare associated infections caused by S. marcescens., Competing Interests: The authors have declared that no competing interests exist.

Background: Although the factors associated to bacterial resistance in patients with asymptomatic bacteriuria (ASB) have been studied in pregnant, fertile age women, patients with spinal cord injury, and those with urogynecological disorders, nothing is known about the factors associated with multidrug-resistant (MDR) bacteria in patients with ASB and planned urological procedures. This study therefore sought to identify the sociodemographic and clinical factors associated with MDR bacteria in a cohort of patients with ASB scheduled for urological procedures., Methods: We conducted a nested case-control study on a cohort of patients with ASB and planned urological procedures at 3 Colombian medical centers. Cases were patients with MDR bacteria and controls were patients without MDR bacteria., Results: A total of 184 patients were included, 41.8% (n = 77) of whom presented ASB with MDR bacteria. The factors linking ASB with MDR bacteria were: advanced age (odds ratio, 1.03; 95% confidence interval, 1.01-1.06) and hospitalization within the 3-month period before surgery (odds ratio, 2.35; 95% confidence interval, 1.08-5.21)., Conclusions: Bacterial resistance is frequent among patients with ASB and planned urological procedures. Advanced age and prior hospitalization should be borne in mind for patients with planned urological procedures because they are factors associated with the presence of MDR bacteria., (Copyright © 2019 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.)

The present study aimed to further clarify the genetic mechanisms responsible for the antimicrobial resistance of Serratia marcescens (S. marcescens) using RNA sequencing. Three drug‑susceptible S. marcescens strains (named MYQT1, MYQT2, and MYQT3) and three multidrug‑resistant S. marcescens strains (named MYQT4, MYQT5, and MYQT6) were isolated from six different patients and subjected to RNA sequencing. Differentially expressed genes (DEGs) between the multidrug‑resistant S. marcescens strains and drug‑susceptible strains were screened and compared, followed by functional enrichment analysis. In addition, a protein‑protein interaction (PPI) network was constructed, and significant modules were extracted from it. Genes enriched in the significant modules were subjected to further enrichment analysis. MYQT3 had very a different expression pattern from MYQT1 and MYQT2, and thus, MYQT3 was excluded from the following analysis. A total of 225 DEGs were identified, of which SMDB11_RS09300 (GTP cyclohydrolase FolE2) was the most significantly upregulated with a log2 FC of 6.4; these DEGs were enriched in different GO terms, including hydrogen sulfide biosynthetic process, sulfur compound transmembrane transporter activity, and ABC transporter complex. Additionally, several genes were identified to be important genes in the PPI network, including SMDB11_RS17755 (upregulated; glutamate synthase large subunit), SMDB11_RS00590 (upregulated; sulfite reductase subunit α), and SMDB11_RS04505 (upregulated; cystathionine β‑synthase). Thus, SMDB11_RS09300, SMDB11_RS17755, SMDB11_RS00590, and SMDB11_RS04505 may play significant roles in the antimicrobial resistance of S. marcescens by participating in folate metabolism or the integrity of cell membranes. However, further experiments are required to clarify these findings.

We investigated the role of the resistance-nodulation-cell division superfamily (RND) efflux system on intrinsic multidrug resistance in Serratia marcescens. We identified eight putative RND efflux system genes in the S. marcescens Db10 genome that included the previously characterized systems, sdeXY, sdeAB, and sdeCDE. Six out of the eight genes conferred multidrug resistance on KAM32, a drug hypersensitive strain of Escherichia coli. Five out of the eight genes conferred resistance to benzalkonium, suggesting the importance of RND efflux systems in biocide resistance in S. marcescens. The energy-dependent efflux activities of five of the pumps were examined using a rhodamine 6 G efflux assay. When expressed in the tolC-deficient strain of E. coli, KAM43, none of the genes conferred resistance on E. coli. When hasF, encoding the S. marcescens TolC ortholog, was expressed in KAM43, all of the genes conferred resistance on E. coli, suggesting that HasF is a major outer membrane protein that is used by all RND efflux systems in this organism. We constructed a sdeXY deletion mutant from a derivative strain of the clinically isolated multidrug-resistant S. marcescens strain and found that the sdeXY deletion mutant was sensitive to a broad spectrum of antimicrobial agents.

Serratia marcescens belongs to the family Enterobacteriaceae, which is commonly found in water, soil, animals, insects, plants. Although S. marcescens displays relatively low virulence, it causes nosocomial infections and outbreaks in severely immunocompromised or critically ill patients, particularly in settings such as intensive care units (ICUs), especially neonatal units (NICUs). This microorganism gives rise to a wide range of clinical manifestations in newborns: from asymptomatic colonization to keratitis, conjunctivitis, urinary tract infections, pneumonia, surgical wound infections, sepsis, bloodstream infection and meningitis. The most frequent site of infection is the bloodstream, followed by the respiratory apparatus and the gastrointestinal tract. Strains of S. marcescens involved in epidemic events have frequently proved to be multi-resistant. Indeed, this species displays intrinsic resistance to several classes of antibiotics. Often, the specific source of the infection cannot be identified. However, the contaminated hands of healthcare workers are believed to be a major vehicle of its transmission. In neonatal intensive care units, colonized or infected newborns are the main potential source of S. marcescens , particularly in the respiratory apparatus, but also in the gastrointestinal tract. The early identification of colonized or infected patients and the prompt implementation of infection control measures, particularly rigorous hand hygiene and contact precautions, are essential in order to curb the spread of infection.

Soft tissue infections occur in over 30% of patients with chemotherapy-induced neutropenia. Gram-positive bacterial infections predominate early in neutropenia, and likelihood of infection by resistant bacteria and fungi increases with prolonged neutropenia. Prior infections and exposures influence the risk of rare pathogens. A 55-year-old woman with chemotherapy-induced neutropenia was scratched on her forearm by a dog. She cleaned the wound with isopropanol and was treated empirically with amoxicillin-clavulanate. Over the next 4 days, she developed fever along with erythema, edema, and mild tenderness of the forearm without purulence or crepitus. She was hospitalized and received empiric treatment with intravenous vancomycin, piperacillin-tazobactam, tobramycin, and voriconazole. Despite therapy, her fevers persisted and the cellulitis progressed for over a week. After 10 days of hospitalization, her neutrophil count began to recover and a bulla developed at the wound site. Culture of the bullous fluid grew Serratia marcescens, and antibiotics were switched to cefepime based on susceptibility. She defervesced and showed substantial improvement of cellulitis within 48 hours and was discharged on oral ciprofloxacin. Serratia marcescens skin infections are rare, and this may be the first report of Serratia cellulitis associated with trauma from dog contact. This case highlights the need to consider unusual pathogens based on exposure history and immune status and to obtain cultures from fluid collections or tissue in cases of treatment-resistant soft tissue infections.

Aim: Serratia marcescens clinical isolates are increasingly resistant to antibiotics. Therefore, the treatment of infections caused by S. marcescens becomes difficult. The aim of this study was to examine the antimicrobial resistance profiles of S. marcescens bacteria isolated from various clinical specimens according to body regions and clinics and to evaluate for enzyme production rates associated with antibiotic resistance of these isolates., Materials and Methods: Blood culture samples were incubated in a fully automated BACTEC-FX system. Identification and antibiogram processing was carried out by fully automated VITEK 2 identification and antibiogram system. The obtained results were retrospectively screened., Results: S. marcescens was identified in a total of 158 clinical specimens. The departments where S. marcescens was most commonly identified were the Anesthesia Intensive Care Unit (25.9%), followed by Chest Diseases (19.6%). Serratia isolates were most commonly determined in blood culture (35.4%) and sputum culture (24.6%). Resistance rates to ceftriaxone and ceftazidime were 22.7% and 19.6%, respectively. However, the rate of resistance detected to cefotaxime and gentamicin (0.6%) was very low., Conclusion: Clinical isolates of Serratia exhibited highest resistance to ceftriaxone, ceftazidime, and piperacillin/tazobactam. However, it was found that the tested Serratia strains did not exhibit high resistance to other antibiotics. Our results suggest that cefotaxime and gentamicin are the most suitable antibiotics for treatment. The extended-spectrum β-lactamase and inducible β-lactamase ratios were found to be decreased by 6%-7%. Although different results may be obtained from different hospitals and regions, it should not be forgotten that Serratia strains may be resistant to many antibiotics and that the results of antibiotic susceptibility testing may help plan antibiotic treatment., Competing Interests: There are no conflicts of interest.

Background: Human infections with Serratia spp. are generally limited to Serratia marcescens and the Serratia liquefaciens complex. There is little data regarding the infections caused by the remaining Serratia spp., as they are seldom isolated from clinical specimens., Methods: In this health care setting in Kathmandu, Nepal routine blood culture is performed on all febrile patients with a temperature >38°C or when there is clinical suspicion of bacteremia. During 2015 we atypically isolated and identified several Serratia spp. We extracted clinical data from these cases and performed whole genome sequencing on all isolates using a MiSeq system (Ilumina, San Diego, CA, USA)., Results: Between June and November 2015, we identified eight patients with suspected bacteremia that produced a positive blood culture for Serratia spp., six Serratia rubidaea and five Serratia marcescens. The S. rubidaea were isolated from three neonates and were concentrated in the neonatal intensive care unit between June and July 2015. All patients were severely ill and one patient died. Whole genome sequencing confirmed that six Nepalese S. rubidaea sequences were identical and indicative of a single-source outbreak., Conclusions: Despite extensive screening we were unable to identify the source of the outbreak, but the inferred timeline suggested that these atypical infections were associated with the aftermath of two massive earthquakes. We speculate that deficits in hygienic behavior, combined with a lack of standard infection control, in the post-earthquake emergency situation contributed to these unusual Serratia spp. outbreaks.

Rationale: Serratia marcescens (S. marcescens) is an opportunistic pathogen of the Enterobacteriaceae family. Although S. marcescens is known to cause sepsis, meningitis, endocarditis, urinary system and ocular infections, skin infections are sporadic. Squamous cell carcinoma (SCC) is the most aggressive skin cancer type that is often located in the head and neck region, and rarely in the scalp tissue., Patient Concerns: An 89-years-old male patient was diagnosed with SCC three years ago. The frontal region of the skull showed an ulcerated tumor, irregular borders, and exophytic growth pattern. The destruction of the frontal bone made the vibrating brain tissue visible, and the lower part had haemopurulent flow., Diagnoses: Gram staining showed the proliferation of gram (-) bacilli. Bacteria were identified as non-pigmented S. marcessens in the wound culture. To the best of our knowledge, there have not been any cases reported with S. marcescens causing cutaneous infections on SCC. Therefore, our report is the first case in the literature., Interventions: According to the culture antibiogram, S. marcescens was ciprofloxacin sensitive. Consequently, 1000 mg/day ciprofloxacin was initiated for 14 days., Outcomes: Purulent exudate in skin cancers may be caused by the nature of carcinoma tissue as well as the colonization of opportunistic pathogen microorganisms as seen in our patient., Lessons: Examination of the wound cultures and elimination of infections are critical in these cases.

Objectives: Antibiotic selective pressure may result in changes to antimicrobial susceptibility throughout the course of infection, especially for organisms that harbour chromosomally encoded AmpC β-lactamases, notably Enterobacter spp., in which hyperexpression of ampC may be induced following treatment with cephalosporins. In this study, we document a case of bacteraemia caused by a blaSME-1-harbouring Serratia marcescens that subsequently developed resistance to expanded-spectrum cephalosporins, piperacillin/tazobactam and fluoroquinolones, over the course of several months of treatment with piperacillin/tazobactam and ciprofloxacin., Methods: Susceptibility testing and WGS were performed on three S. marcescens isolates from the patient. β-Lactamase activity in the presence or absence of induction by imipenem was measured by nitrocefin hydrolysis assays. Expression of ampC and blaSME-1 under the same conditions was determined by real-time PCR., Results: WGS demonstrated accumulation of missense and nonsense mutations in ampD associated with stable derepression of AmpC. Gene expression and β-lactamase activity of both AmpC and SME-1 were inducible in the initial susceptible isolate, but were constitutively high in the resistant isolate, in which total β-lactamase activity was increased by 128-fold., Conclusions: Although development of such in vitro resistance due to selective pressure imposed by antibiotics is reportedly low in S. marcescens, our findings highlight the need to evaluate isolates on a regular basis during long-term antibiotic therapy.

Background: Quorum sensing is a cell-to-cell communication system in bacteria that controls the production of virulence factors. Serratia marcescens is a causative agent of hospital-acquired infections that shows high resistance to antibiotics. This makes the treatment of these infections difficult. Quorum sensing regulates the production of virulence factors of S. marcescens such as prodigiosin, protease, swimming and swarming motilities and formation of biofilms. Inhibition of quorum sensing may be an alternative to antibiotic treatment to avoid emergence of resistance., Objectives: Testing the ability of glyceryl trinitrate to inhibit quorum sensing and virulence factors of Serratia marcescens ., Methods: The inhibiting activities of sub-inhibitory concentration of glyceryl trinitrate against the quorum-sensing regulated violacein pigment in Chromobacterium violaceum CV026 was performed to evaluate the anti-quorum sensing effect of glyceryl trinitrate. The anti-virulence activity was assessed against prodigiosin, protease, biofilm formation in addition to swimming and swarming motilities., Results: Glyceryl trinitrate at at a concentration of 0.25 mg/ml produced significant inhibitory effects against violacein (67.01%), prodigiosin (82.67%), protease, swimming (36.72%) and swarming (79.31%) motilities and biofilm formation (87.83%)., Conclusion: Glyceryl trinitrate is a quorum sensing and virulence inhibitor that may be useful in treatment of nosocomial infections caused by Serratia marcescens .

Purpose: There is currently a paucity of published literature focused on the treatment of infections caused by NDM-producing organisms., Methods: We describe a case of a bacteraemia caused by an extensively drug-resistant (XDR) New Delhi metallo-β-lactamase (NDM)-producing Serratia marcescens and review the treatment options for XDR NDM-producing Enterobacteriaceae., Results: Infections caused by New Delhi beta-lactamase (NDM)-producing Enterobacteriaceae are becoming increasingly prevalent worldwide. The presence of the enzyme results in multidrug-resistant and extensively drug-resistant phenotypes which often pose a treatment challenge. Despite this challenge, case reports and series have demonstrated good clinical outcomes with numerous treatment options in comparison to infections due to KPC-producing Enterobacteriaceae., Conclusions: Further good-quality research focused on the treatment of NDM-producing Enterobacteriaceae is warranted.

Purpose: To present our experience in the management of superior ophthalmic vein thrombosis (SOVT), which is a rare, but extremely serious condition if not recognized and managed promptly and appropriately., Methods: Two patients with septic and aseptic SOVT are presented. Clinical characteristics, radiographic features, management techniques, and outcomes are described., Results: In the first case thrombosis occurred as a complication of functional endoscopic sinus surgery. In the second case thrombosis occurred as a complication of untreated inflammatory bowel disease: ulcerative colitis. Both cases resulted with permanent unilateral blindness., Conclusion: SOVT is a rare entity. There are no guidelines, just recommendations for disease management. Based on our experience, broad-spectrum intravenous antibiotic, anticoagulation, and steroid therapy should be promptly introduced and if needed surgical intervention. SOVT can lead to devastating complications which include permanent loss of vision and in some cases a fatal outcome.

The emergence and spread of carbapenem-resistant gram-negative bacteria poses a serious threat to human health worldwide. Currently, little is known about the molecular mechanisms underlying carbapenem resistance and their prevalence among gram-negative bacteria in Egypt. In this study, we analyzed carbapenemase production in gram-negative bacteria isolated from hospitalized patients in Egypt in 2014. All isolates were subjected to phenotypic and genotypic susceptibility testing for carbapenem resistance. Our results indicated a high level of carbapenem-resistant gram-negative bacteria in Egypt, with 50.8% of the isolates harboring at least one carbapenem resistance gene. OXA-48-like and NDM-1 were the most prevalent carbapenemases, being detected in 49.2%, and 47.7% of carbapenemase-positive isolates, respectively, whereas Verona integron-encoded metallo-β-lactamase (VIM) was detected in only 26.2% of carbapenemase-positive isolates. This study reports for the first time carbapenemase-producing Serratia marcescens, Morganella morganii, and bla VIM-1-like -producing Pseudomonas aeruginosa in Egypt. It is also the first demonstration of the coexistence of different carbapenemases, being detected in 21.5% of carbapenemase-positive isolates. Effective antibiotic supervision, regional surveillance, and early detection of carbapenemase producers are imperative to prevent their future spread to epidemic levels.

Acute bacterial parotitis is uncommon in young adults. Infection with Serratia marcescens is even rarer and usually found in hospitalized patients. This case report focuses on a young woman with acute bacterial parotitis caused by S. marcescens that required a longer-than-normal course of antibiotics.

The intrinsic polymyxin resistance displayed by Serratia marcescens makes the acquisition of carbapenemase encoding genes a worrisome event. This study report a SME-4-producing S. marcescens isolate causing septic shock in Brazil. The insertion of novel resistance determinants and their consequent spread in our territory is noteworthy., (Copyright © 2017 Elsevier Inc. All rights reserved.)

The metallo-beta-lactamase GIM-1 has been found in various bacterial host species nearly exclusively in western Germany. However, not much is known about the epidemiology of GIM-1-positive Serratia marcescens Here we report on a surprisingly protracted regional dissemination. In-hospital transmission was investigated by using conventional epidemiological tools to identify spatiotemporal links. Strain typing was performed using pulsed-field gel electrophoresis (PFGE) and whole-genome sequencing (WGS). Bayesian phylogeny was used to infer the time axis of the observed occurrence. Thirteen S. marcescens strains from 10 patients from 6 different German hospitals were investigated. Suspected in-hospital transmissions were confirmed by molecular typing at a higher resolution by WGS than by PFGE. A detailed sequence analysis demonstrated the spread of one predominant strain variant but also provided evidence for transfer of the bla GIM-1 gene cassette between different strains. A Bayesian phylogenetic analysis showed that the most recent common ancestor of the identified clonal cluster could be dated back to April 1993 (95% highest posterior density interval, January 1973 to March 2003) and that this strain might have already harbored the bla GIM-1 at that time and, therewith, years before the first detection of this resistance gene in clinical specimens. This study shows a long-standing clonal and plasmid-mediated expansion of GIM-1-producing S. marcescens that might have gone unnoticed in the absence of a standardized and effective molecular screening for carbapenemases. The systematic and early detection of resistance is thus highly advisable, especially for the prevention of potentially long-term dissemination that may progress beyond control., (Copyright © 2017 American Society for Microbiology.)

Purpose: In 2013, the German Commission for Hospital Hygiene and Infectious Disease Prevention (KRINKO) stated that extending weekly colonisation screening from very low birth weight (VLBW) infants (<1500 g) to all patients in the Neonatal Intensive Care Unit (NICU) might be useful., Methods: After implementing this recommendation, we detected a previously unnoticed cluster of Serratia marcescens. Strains were typed by Pulsed Field Gel Electrophoresis (PFGE)., Results: Over 6 months, 19 out of 159 infants acquired S. marcescens. Twelve of the nineteen patients with S. marcescens were non-VLBW infants, and they were colonised significantly earlier than were VLBW infants (median 17 vs. 28 days; p < 0.01). Molecular typing revealed a polyclonal outbreak with multiple strain types leading to one or two transmissions each and a dominating outbreak strains being involved in an explosive outbreak involving eight neonates., Conclusion: The revised KRINKO recommendation may help identify unnoticed outbreaks. Colonised non-VLBW patients may be an underestimated source of S. marcescens.

Unlabelled: Serratia marcescens is a Gram-negative, encapsulated, motile, anaerobic, non-sporulating bacillus that belongs to the Enterobacteriaceae family. It is found in water, soil, plants, food, and garbage. S. marcescens is an opportunistic pathogen. It usually causes nosocomial infections, such as lung and genitourinary infections, sinusitis, otitis, endocarditis, and sepsis. Skin infections caused by S. marcescens are rare. To describe three new cases of skin ulcers of the leg caused by S. marcescens and review the relevant literature. We investigated three patients admitted for ulcers on the leg., Results: In two patients, post-traumatic aetiology was concluded. The modality of infection was not identified for the other patient. One patient was diabetic. All patients recovered with specific antibiotic therapy (ciprofloxacin, ceftriaxone and levofloxacin, respectively). Skin ulcers due to S. marcescens are very rare. The three cases presented here add to the limited literature of skin infections caused by S. marcescens.

We present 2 cases of a 3-month-old girl and boy who were diagnosed with an infected pseudoaneurysm 2 months after undergoing left-sided modified Blalock-Taussig shunt (mBTS) operations for pulmonary atresia. Because the shunts in both cases were nearly obstructed, they underwent a 2-stage surgical approach: classic BTS operations through a right thoracotomy to establish sufficient pulmonary flow and infected graft removal through a median sternotomy after close observation of the state of the aneurysms. By utilizing autologous tissue from a different thoracic entry, both patients were successfully managed and recovered without any recurrence of infection., (Copyright © 2016 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)

The role of Serratia marcescens changed from a harmless saprophytic microorganism to an important opportunistic human pathogen. It often causes nosocomial device-associated outbreaks and rarely serious invasive community acquired infections. We present a case of a community-acquired Serratia marcescens bacteremia leading to Respiratory Distress Syndrome in a previously healthy 51-year-old man without identifiable risk factors. Full recovery was achieved with solely medical treatment and observation in ICU during three days. To our knowledge it is an extremely uncommon presentation and just few cases have been previously reported in the literature.

Background: Many antibiotics have no effect on Gram-positive and Gram-negative microbes, which necessitates the prescription of broad-spectrum antimicrobial agents that can lead to increased risk of antibiotic resistance. These pathogens constitute a further threat because they are also resistant to numerous beta-lactam antibiotics, as well as other antibiotic groups. This study retrospectively investigates antimicrobial resistance in hospitalized patients suffering from pneumonia triggered by Gram-negative Serratia marcescens or Proteus mirabilis., Methods: The demographic and clinical data analyzed in this study were obtained from the clinical databank of the HELIOS Clinic, Witten/Herdecke University, Wuppertal, Germany, for inpatients presenting with pneumonia triggered by S. marcescens or P. mirabilis from 2004 to 2014. An antibiogram was conducted for the antibiotics utilized as part of the management of patients with pneumonia triggered by these two pathogens., Results: Pneumonia was caused by Gram-negative bacteria in 115 patients during the study period from January 1, 2004, to August 12, 2014. Of these, 43 (37.4 %) hospitalized patients [26 males (60.5 %, 95 % CI 45.9 %-75.1 %) and 17 females (39.5 %, 95 % CI 24.9 %-54.1 %)] with mean age of 66.2 ± 13.4 years had pneumonia triggered by S. marcescens, while 20 (17.4 %) patients [14 males (70 %, 95 % CI 49.9 %-90.1 %) and 6 females (30 %, 95 % CI 9.9 %-50.1 %)] with a mean age of 64.6 ± 12.8 years had pneumonia caused by P. mirabilis. S. marcescens showed an increased antibiotic resistance to ampicillin (100 %), ampicillin-sulbactam (100 %), and cefuroxime (100 %). P. mirabilis had a high resistance to tetracycline (100 %) and ampicillin (55 %). S. marcescens (P < 0.0001) and P. mirabilis (P = 0.0003) demonstrated no resistance to cefepime in these patients with pneumonia., Conclusions: S. marcescens and P. mirabilis were resistant to several commonly used antimicrobial agents, but showed no resistance to cefepime.

Objectives: This systematic review and meta-analysis compared effects of different antibiotics on mortality in patients with bloodstream infections caused by Enterobacteriaceae with chromosomal AmpC β-lactamase., Methods: Databases were systematically searched for studies reporting mortality in patients with bloodstream infections caused by AmpC producers treated with carbapenems, broad-spectrum β-lactam/β-lactamase inhibitors (BLBLIs), quinolones or cefepime. Pooled ORs for mortality were calculated for cases that received monotherapy with these agents versus carbapenems., Registration: PROSPERO international prospective register of systematic reviews (CRD42014014992; 18 November 2014)., Results: Eleven observational studies were included. Random-effects meta-analysis was performed on studies reporting empirical and definitive monotherapy. In unadjusted analyses, no significant difference in mortality was found between BLBLIs versus carbapenems used for definitive therapy (OR 0.87, 95% CI 0.32-2.36) or empirical therapy (OR 0.48; 95% CI 0.14-1.60) or cefepime versus carbapenems as definitive therapy (OR 0.61; 95% CI 0.27-1.38) or empirical therapy (0.60; 95% CI 0.17-2.20). Use of a fluoroquinolone as definitive therapy was associated with a lower risk of mortality compared with carbapenems (OR 0.39; 95% CI 0.19-0.78). Three studies with patient-level data were used to adjust for potential confounders. The non-significant trends favouring non-carbapenem options in these studies were diminished after adjustment for age, sex and illness severity scores, suggestive of residual confounding., Conclusions: Despite limitations of available data, there was no strong evidence to suggest that BLBLIs, quinolones or cefepime were inferior to carbapenems. The reduced risk of mortality observed with quinolone use may reflect less serious illness in patients, rather than superiority over carbapenems., (© The Author 2015. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.)

Serratia marcescens is a Gram-negative bacillus belonging to the Enterobacteriaceae family. Because of increasing reports of antimicrobial resistance, this bacterium has received considerable attention and has emerged as an important pathogen. In order to reveal clinical and microbiological characteristics of S. marcescens cutaneous infection and to suggest appropriate antibiotic treatment, we retrospectively analyzed 17 strains isolated from wound swabs of Korean patients between November 2005 and March 2014. A total of 13 patients (five men and eight women) were included in our study, with a mean age of 46.3 years (range, 21-82). Based on medical history, seven patients were classified as immunocompromised. Prior predisposing factors for infections were noted in 12 patients, including pre-existing leg ulcers or dermatitis (5/13), preceding cancer surgeries (2/13), plastic surgeries and filler injection (2/13), traumas (2/13) and medical procedures following cutaneous abscess (1/13). Cutaneous infections showed various clinical presentations, including spontaneous dermal abscess, fingernail change, painful nodules and papular erosions. We found that third- and fourth-generation cephalosporins, gentamicin, levofloxacin and meropenem appeared active against all 17 strains in vitro. Clinically, all patients treated with empirical first-generation cephalosporin showed treatment resistance, and oral quinolone monotherapy was the most preferred antibiotic regimen without treatment failure, with an average treatment duration of 25 days (range, 14-42). This study demonstrates the various clinical presentations and treatment responses for cutaneous S. marcescens infection. Moreover, we suggest that initial antibiotic coverage should be broad enough to account for multidrug resistance in this rare pathogen., (© 2015 Japanese Dermatological Association.)