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1.  Outbreak of Serratia marcescens Bloodstream Infections in Patients Receiving Parenteral Nutrition Prepared by a Compounding Pharmacy 
Nineteen Serratia marcescens bloodstream infections, including 9 deaths, were linked to contaminated parenteral nutrition prepared by a compounding pharmacy. The investigation identified several deficiencies in sterile compounding procedures, reaffirming the need for improved adherence to sterile compounding standards.
Background. Compounding pharmacies often prepare parenteral nutrition (PN) and must adhere to rigorous standards to avoid contamination of the sterile preparation. In March 2011, Serratia marcescens bloodstream infections (BSIs) were identified in 5 patients receiving PN from a single compounding pharmacy. An investigation was conducted to identify potential sources of contamination and prevent further infections.
Methods. Cases were defined as S. marcescens BSIs in patients receiving PN from the pharmacy between January and March 2011. We reviewed case patients’ clinical records, evaluated pharmacy compounding practices, and obtained epidemiologically directed environmental cultures. Molecular relatedness of available Serratia isolates was determined by pulsed-field gel electrophoresis (PFGE).
Results. Nineteen case patients were identified; 9 died. The attack rate for patients receiving PN in March was 35%. No case patients were younger than 18 years. In October 2010, the pharmacy began compounding and filter-sterilizing amino acid solution for adult PN using nonsterile amino acids due to a national manufacturer shortage. Review of this process identified breaches in mixing, filtration, and sterility testing practices. S. marcescens was identified from a pharmacy water faucet, mixing container, and opened amino acid powder. These isolates were indistinguishable from the outbreak strain by PFGE.
Conclusions. Compounding of nonsterile amino acid components of PN was initiated due to a manufacturer shortage. Failure to follow recommended compounding standards contributed to an outbreak of S. marcescens BSIs. Improved adherence to sterile compounding standards, critical examination of standards for sterile compounding from nonsterile ingredients, and more rigorous oversight of compounding pharmacies is needed to prevent future outbreaks.
PMCID: PMC4305132  PMID: 24729502
compounding; contamination; outbreak; nutrition; Serratia
2.  Kinetic properties of Serratia marcescens adenosine 5'-diphosphate glucose pyrophosphorylase. 
Journal of Bacteriology  1976;127(1):193-203.
The regulatory properties of partially purified adenosine 5'-diphosphate-(ADP) glucose pyrophosphorylase from two Serratia marcescens strains (ATCC 274 and ATCC 15365) have been studied. Slight or negligible activation by fructose-P2, pyridoxal-phosphate, or reduced nicotinamide adenine dinucleotide phosphate (NADPH) was observed. These compounds were previously shown to be potent activators of the ADPglucose pyrophosphorylases from the enterics, Salmonella typhimurium, Enterobacter aerogenes, Enterobacter cloacae, Citrobacter freundii, Escherichia aurescens, Shigella dysenteriae, and Escherichia coli. Phosphoenolpyruvate stimulated the rate of ADPglucose synthesis catalyzed by Serratia ADPglucose pyrophosphorylase about 1.5- to 2-fold but did not affect the S0.5 values (concentration of substrate required for 50% maximal stimulation) of the substrates, alpha-glucose-1-phosphate, and adenosine 5'-triphosphate. Adenosine 5'-monophosphate (AMP), a potent inhibitor of the enteric ADPglucose pyrophosphorylase, is an effective inhibitor of the S. marcescens enzyme. ADP also inhibits but is not as effective as AMP. Activators of the enteric enzyme counteract the inhibition caused by AMP. This is in contrast to what is observed for the S. marcescens enzyme. Neither phosphoenolpyruvate, fructose-diphosphate, pyridoxal-phosphate, NADPH, 3-phosphoglycerate, fructose-6-phosphate, nor pyruvate effect the inhibition caused by AMP. The properties of the S. marcescens HY strain and Serratia liquefaciens ADPglucose pyrophosphorylase were found to be similar to the above two S. marcescens enzymes with respect to activation and inhibition. These observations provide another example where the properties of an enzyme found in the genus Serratia have been found to be different from the properties of the same enzyme present in the enteric genera Escherichia, Salmonella, Shigella, Citrobacter, and Enterobacter.
PMCID: PMC233051  PMID: 6432
3.  Growth and survival of Serratia marcescens under aerobic and anaerobic conditions in the presence of materials from blood bags. 
Journal of Clinical Microbiology  1993;31(7):1826-1830.
Several patients receiving blood transfusions during the summer of 1991 developed bacteremia after the transfusion. In all cases, the infection was caused by Serratia marcescens. The same strain of Serratia marcescens was isolated from the patients and from the outer surface of unfilled blood bags. The transport containers for the blood bags were made anoxic by using a catalyst in order to prevent microbial growth. The survival and growth of S. marcescens K202, which was isolated from the blood bags, was studied at different oxygen concentrations in deionized water containing materials derived from the blood bags. The rate of survival and growth of S. marcescens was highest under anaerobic conditions, in which growth occurred with all materials and even in deionized water alone. In contrast, S. marcescens did not survive in control cultures under semi-anaerobic and aerobic conditions. Growth was observed, however, under both aerobic and semi-anaerobic conditions in the presence of each of the tested blood bag materials. These findings indicate that the conditions in the transport containers for the blood bags were favorable for the survival and growth of S. marcescens.
PMCID: PMC265640  PMID: 8349760
Journal of Bacteriology  1963;85(4):918-926.
Bateman, J. B. (U.S. Army Biological Laboratories, Fort Detrick, Frederick, Md.) and F. Elizabeth White. Effect of relative humidity on the survival of Serratia marcescens in concentrated glycerol and sucrose solutions. J. Bacteriol. 85:918–926. 1963.—The effects of sucrose and glycerol upon the ability of Serratia marcescens to grow when restored to a normal medium after exposure to solutions of these substances were examined, with special attention to the prevailing thermodynamic activity of water in these solutions as a factor of supposed primary importance in influencing survival or death of cells. The data were notable for the absence of any zones of instability such as those found when the water activity is changed by exposure of washed cells to water vapor at controlled relative humidities (RH). The cells survived indefinitely at room temperature in concentrated sucrose solutions; in glycerol solutions of equilibrium RH values from 20 to 90, the first-order decay constants were about 0.03 to 0.1 hr−1. These results, considered together with the contrasting phenomenon of narrow lethal humidity zones found in vapor-phrase equilibration experiments, were explained generally in terms of competitive interactions involving concentrated intrinsic and adventitious solutes, the cell water, and the organized structures of the cell, whose integrity was considered to depend ultimately upon the net effect of these various interactions.
PMCID: PMC278245  PMID: 14044963
5.  Relative Humidity and the Killing of Bacteria 
Applied Microbiology  1961;9(6):567-571.
The viability of washed moist cells of Serratia marcescens after storage has been measured in relation to variations in the prior treatment of the cells and in conditions of storage. The factors considered were: (i) water content during storage; (ii) method of arriving at water content (partial drying in vacuum or freeze-drying and addition of water); (iii) presence or absence of air during storage.
Increasingly rapid decay occurs as the water content at which the cells are stored is diminished from above 90% to 20 or 30% (“critical” water content). It occurs in presence or absence of air and it occurs whether the final water content is approached by removal of water from wet cells or by addition of water to freeze-dried cells.
The rate of decay during storage at 20 to 30% water is somewhat diminished by the presence of air (“protective” effect of air).
As the water content is further reduced to less than 10%, the stability of cells stored in a vacuum approaches that of wet cells. In presence of air the reverse is true: the stability decreases until at less than 1% water, the decay rate is about as great as at the “critical” water content (“toxic” effect of air).
Particularly rapid decay of S. marcescens at the “critical” water content has escaped attention in aerosol studies because accurate control of relative humidity (RH) in this region, RH 94 to 99%, is virtually impossible in such studies. On the other hand, values of decay rates referred to measured water contents are quite unreliable in the 20 to 80% RH zone because the corresponding variation of water content is too small to measure reliably. Thus data of the kind reported in this paper cannot be directly compared to the published results of studies of air-borne bacteria, although they are relevant to the practical question of air-borne infection in humid atmospheres.
PMCID: PMC1057789  PMID: 13865722
6.  Survival of Airborne Bacteria in a High Urban Concentration of Carbon Monoxide1 
Applied Microbiology  1973;25(1):86-91.
Vegetative cells of Serratia marcescens 8UK, Sarcina lutea, and spores of Bacillus subtilus var. niger were held in aerosols, with and without an urban concentration of CO (85 μliters per liter or ppm), for up to 6 hr at 15 C and a relative humidity (RH) of approximately 0, 25, 50, 75, and 95%. It was found that CO enhanced the death rate of S. marcescens 8UK at least four- to sevenfold at low RH (ca. 1 to 25%), but protected the cells at high RH (ca. 90%). Death rates of S. lutea, with or without added CO, were comparatively low over the entire RH range. However, in the first hour, airborne S. lutea held in CO-containing air were more stable than those in air without added CO (i.e., CO protection). A marked increase in the death rate (up to 70-fold) occurred in the subsequent 5 hr within the RH range of approximately 0 to 75%. Statistical analysis indicated that aerosol decay rates of B. subtilus var. niger spores decreased significantly, when held in a CO-containing as compared to a non-CO-containing atmosphere, in the 0 to 85% RH range. Thus, the data presented indicate that CO in the urban environment may have a protective or lethal effect on airborne bacteria, dependent upon at least the microbial species, aerosol age, and relative humidity. A mechanism for CO death enhancement and protection of airborne S. marcescens 8UK is suggested to involve CO uncoupling of an energy-requiring death mechanism and an energy-requiring maintenance mechanism at high and low RH, respectively.
PMCID: PMC380740  PMID: 4631439
7.  Systematic Analysis of White Pox Disease in Acropora palmata of the Florida Keys and Role of Serratia marcescens 
Applied and Environmental Microbiology  2015;81(13):4451-4457.
White pox disease (WPD) affects the threatened elkhorn coral, Acropora palmata. Owing in part to the lack of a rapid and simple diagnostic test, there have been few systematic assessments of the prevalence of acroporid serratiosis (caused specifically by Serratia marcescens) versus general WPD signs. Six reefs in the Florida Keys were surveyed between 2011 and 2013 to determine the disease status of A. palmata and the prevalence of S. marcescens. WPD was noted at four of the six reefs, with WPD lesions found on 8 to 40% of the colonies surveyed. S. marcescens was detected in 26.9% (7/26) of the WPD lesions and in mucus from apparently healthy colonies both during and outside of disease events (9%; 18/201). S. marcescens was detected with greater frequency in A. palmata than in the overlying water column, regardless of disease status (P = 0.0177). S. marcescens could not be cultured from A. palmata but was isolated from healthy colonies of other coral species and was identified as pathogenic pulsed-field gel electrophoresis type PDR60. WPD lesions were frequently observed on the reef, but unlike in prior outbreaks, no whole-colony death was observed. Pathogenic S. marcescens was circulating on the reef but did not appear to be the primary pathogen in these recent WPD episodes, suggesting that other pathogens or stressors may contribute to signs of WPD. Results highlight the critical importance of diagnostics in coral disease investigations, especially given that field manifestation of disease may be similar, regardless of the etiological agent.
PMCID: PMC4475871  PMID: 25911491
8.  Kinetic Analysis of Growth Rate, ATP, and Pigmentation Suggests an Energy-Spilling Function for the Pigment Prodigiosin of Serratia marcescens▿  
Journal of Bacteriology  2008;190(22):7453-7463.
Serratia marcescens is a gram-negative environmental bacterium and opportunistic pathogen. S. marcescens expresses prodigiosin, a bright red and cell-associated pigment which has no known biological function for producing cells. We present here a kinetic model relating cell, ATP, and prodigiosin concentration changes for S. marcescens during cultivation in batch culture. Cells were grown in a variety of complex broth media at temperatures which either promoted or essentially prevented pigmentation. High growth rates were accompanied by large decreases in cellular prodigiosin concentration; low growth rates were associated with rapid pigmentation. Prodigiosin was induced most strongly during limited growth as the population transitioned to stationary phase, suggesting a negative effect of this pigment on biomass production. Mathematically, the combined rate of formation of biomass and bioenergy (as ATP) was shown to be equivalent to the rate of prodigiosin production. Studies with cyanide inhibition of both oxidative phosphorylation and pigment production indicated that rates of biomass and net ATP synthesis were actually higher in the presence of cyanide, further suggesting a negative regulatory role for prodigiosin in cell and energy production under aerobic growth conditions. Considered in the context of the literature, these results suggest that prodigiosin reduces ATP production by a process termed energy spilling. This process may protect the cell by limiting production of reactive oxygen compounds. Other possible functions for prodigiosin as a mediator of cell death at population stationary phase are discussed.
PMCID: PMC2576671  PMID: 18805986
9.  Serum bactericidal activity and postantibiotic effect in serum of patients with urinary tract infection receiving high-dose amikacin. 
Ten patients received a 30-min infusion of amikacin (30 mg/kg) on day 1 and 15 mg/kg on day 2. Mean serum creatinine was 1.1 +/- 0.3 (standard deviation) mg/dl before and 1.0 +/- 0.3 mg/dl 3 days after the second infusion. Mean serum amikacin concentrations before, at the end of infusion, and 1, 6, 12, and 24 h after 30 and 15 mg/kg were 0, 157, 79, 31, 16, 5, 5, 85, 51, 19, 12, and 5 mg/liter, respectively. Five strains each of Staphylococcus aureus, Staphylococcus epidermidis susceptible and resistant to oxacillin, Streptococcus (Enterococcus) faecalis, corynebacterium sp. strain JK, Listeria monocytogenes, Mycobacterium fortuitum (three strains), Klebsiella pneumoniae, Serratia marcescens, Acinetobacter calcoaceticus, and Pseudomonas aeruginosa were tested. Serum bactericidal activities (SBAs) were greater than or equal to 1:8 in greater than or equal to 80% of the sera 1 and 6 h after 30 mg/kg and in greater than or equal to 60% of the sera 1 and 6 h after 15 mg/kg against Staphylococcus aureus and Staphylococcus epidermidis susceptible to oxacillin, A. calcoaceticus, and K. pneumoniae. L. monocytogenes, Serratia marcescens, and P. aeruginosa had lower SBAs. Very low or no activity was observed against oxacillin-resistant staphylococci and Streptococcus faecalis. The study of the killing rate in serum confirmed these results. Postantibiotic effect was studied by incubating a strain from each species in serum samples obtained 1 and 6 h after both regimens for 0.5, 1, or 2 h. The duration of postantibiotic effect depended on the duration of contact and the concentration of amikacin for the following organisms: oxacillin-susceptible staphylococci, L. monocytogenes, P. aeruginosa, A. calcoaceticus, K. pneumoniae, and Serratia marcescens. M. fortuitum was killed after 30 min of contact. No postantibiotic effect was observed with Streptococcus faecalis, Corynebacterium sp. strain JK, or oxacillin-resistant staphylococci. Amikacin at 30 mg/kg provided high levels and SBAs against susceptible pathogens. Prolonged postantibiotic effects were observed. No signs of nephrotoxicity occurred.
PMCID: PMC174872  PMID: 3116918
10.  Value of microbiology study in congenital nasolacrimal duct obstruction 
Saudi Journal of Ophthalmology  2012;26(2):223-228.
Evaluation of the effect of different microorganisms on congenital nasolacrimal duct obstruction (CNLDO) tightness and whether probing or silastic intubation is likely to fail in a particular microorganism infection.
The culture and sensitivity results of lacrimal drainage system (LDS) discharge samples from patients with CNLDO were reviewed. Different microorganisms were correlated with the severity of nasolacrimal duct (NLD) obstruction observed during surgical intervention. The success rates of probing and silastic intubation as a primary procedure for each identifiable microorganism were documented. Statistical analysis was conducted to correlate the type of microorganism with the tightness of CNLDO and treatment failure.
Out of 181 specimens, 22 had no growth (12.1%). LDS with positive culture had 76.6% successful probing (n = 49) and 82.1% successful silastic intubation (n = 78). Gram-positive and Gram-negative species were almost equally detected. The most prevalent organisms were Streptococcus pneumoniae and Hemophilus influenzae (48.1% and 39.2%, respectively). Tight CNLDO was more prevalent in Serratia marcescens (n = 2; 100%) and Staphylococcus aureus (n = 4; 33.3%) infections with a 7.75 Odds ratio [95% confidence interval (CI), 1.67–34.63]. Staphylococcus aureus had 37.5% successful probing; however, success was achieved in all cases with silastic intubation. Serratia marcescens infections had 100% successful silastic intubation.
Microbiology study can predict tight CNLDO and helps in choosing the most successful treatment option. CNLDO with Staphylococcus infection and Serratia marcescens were likely to have tight NLD obstruction and silastic intubation had better outcomes.
PMCID: PMC3729323  PMID: 23960996
Microbiology; Congenital; Nasolacrimal duct; Obstruction
11.  A rare pathogen for subacute osteomyelitis in adolescent: Serratia marcescens 
•Serratia species are rare pathogens for osteomyelitis.•Orthopedic surgeons should be aware of opportunistic microorganism like serratia.•Osteomyelitis is one of the factors for union delay or nonunion, we should be alert.•Osteomyelitis treatment consists of debridement and antibiotics.
There are various pathogens reported for osteomyelitis. Osteomyelitis is bone infection which produces pain and fever, also threatens bone instability. It can lead to nonunion. The purpose of this report was to describe a case with union delay of the tibia due to serratia marcescens osteomyelitis. Serratia marcescens is an unexpected pathogen for subacute osteomyelitis in adolescence. Because of difficulty of diagnosis, treatment can be delayed or the situation can cause complications like nonunion or loss of function.
Serratia marcescens is an unexpected pathogen for subacute osteomyelitis in adolescence. Because of difficulty of diagnosis, treatment can be delayed or cause complications like nonunion or loss of function. We present a meningomyelocele female adolescent operated with distal tibia varus osteotomy for correcting ankle valgus deformity. Insufficient healing was determined at osteotomy side on radiographs. The patient's erythrocyte sedimentation rate and CRP level was slightly higher with minimal clinical inflammation. MRI examination showed abscess formation at T2 imaging. Debridement, grafting and circular external fixation was performed. Sulperazon was started for drug therapy. Union was achieved after compression and distraction osteogenesis by circular external fixator.
Orthopedic surgeons should be aware of opportunistic infections like serratia and keep in mind as a probable cause of disease.
Osteomyelitis is one of our main problems in orthopedics. Serratia does not come to mind as a causative factor when we learn the patient has osteomyelitis. We give treatment for the most expected pathogens like staphylococcus species firstly. This shows us the importance of bone biopsies and wound culture tests. Presented case is diagnosed as serratia osteomyelitis after culture results and given treatment with antibiotics and debridement.
Orthopedic surgeons should be aware of opportunistic infections like serratia and keep in mind when diagnosing the unexpected problem.
PMCID: PMC4353985  PMID: 25704404
Serratia marcescens; Osteomyelitis; Infection; Debridement; Orthopedics; Meningomyelocele
12.  Requirement for Serratia marcescens Cytolysin in a Murine Model of Hemorrhagic Pneumonia 
Infection and Immunity  2014;83(2):614-624.
Serratia marcescens, a member of the carbapenem-resistant Enterobacteriaceae, is an important emerging pathogen that causes a wide variety of nosocomial infections, spreads rapidly within hospitals, and has a systemic mortality rate of ≤41%. Despite multiple clinical descriptions of S. marcescens nosocomial pneumonia, little is known regarding the mechanisms of bacterial pathogenesis and the host immune response. To address this gap, we developed an oropharyngeal aspiration model of lethal and sublethal S. marcescens pneumonia in BALB/c mice and extensively characterized the latter. Lethal challenge (>4.0 × 106 CFU) was characterized by fulminate hemorrhagic pneumonia with rapid loss of lung function and death. Mice challenged with a sublethal dose (<2.0 × 106 CFU) rapidly lost weight, had diminished lung compliance, experienced lung hemorrhage, and responded to the infection with extensive neutrophil infiltration and histopathological changes in tissue architecture. Neutrophil extracellular trap formation and the expression of inflammatory cytokines occurred early after infection. Mice depleted of neutrophils were exquisitely susceptible to an otherwise nonlethal inoculum, thereby demonstrating the requirement for neutrophils in host protection. Mutation of the genes encoding the cytolysin ShlA and its transporter ShlB resulted in attenuated S. marcescens strains that failed to cause profound weight loss, extended illness, hemorrhage, and prolonged lung pathology in mice. This study describes a model of S. marcescens pneumonia that mimics known clinical features of human illness, identifies neutrophils and the toxin ShlA as a key factors important for defense and infection, respectively, and provides a solid foundation for future studies of novel therapeutics for this important opportunistic pathogen.
PMCID: PMC4294263  PMID: 25422267
13.  Relationship Between Atmospheric Temperature and Survival of Airborne Bacteria 
Applied Microbiology  1970;19(2):245-249.
Effects of temperatures ranging from −40 to 49 C on the behavior of airborne Serratia marcescens, Escherichia coli, and Bacillus subtilis var. niger were investigated. Aerosol decay rates of B. subtilis spores were not significantly affected by the temperature and remained approximately constant within the temperature range studied. The survival of airborne S. marcescens and E. coli was closely related to the temperature. An increase in temperature from −18 to 49 C resulted in a progressive increase of the biological death rate, and the relationship between the biological death rate and the temperature appeared to be linear. An increase in temperature from 24 to 49 C resulted in significantly reduced aerosol recoveries of the two vegetative organisms. At −40 C, the aerosol recovery of all three agents was consistently lower than at −18 to 24 C.
PMCID: PMC376659  PMID: 4985428
14.  Evaluation of RapID onE system for identification of 379 strains in the family Enterobacteriaceae and oxidase-negative, gram-negative nonfermenters. 
Journal of Clinical Microbiology  1994;32(4):931-934.
The ability of the RapID onE system (Innovative Diagnostic Systems, Inc., Norcross, Ga.) to identify 364 strains in the family Enterobacteriaceae and 15 oxidase-negative, gram-negative, nonfermentative rods was evaluated. Kits were inoculated with no. 2 McFarland standard suspensions, and reactions were interpreted after 4 h of incubation at 35 degrees C. Overall, the method correctly identified (to the species level or to the genus level for salmonellas and non-Shigella sonnei Shigella species) 363 strains (95.8%) without additional tests. For four strains (1.0%), additional tests were required to delineate the correct identification from a range of two or more possibilities; these included one Serratia liquefaciens (Serratia marcescens or Serratia liquefaciens), one Serratia rubidaea (Serratia rubidaea or Serratia odorifera), one Salmonella typhi (Leminorella richardii or Salmonella sp.) and one Yersinia enterocolitica (Yersinia frederiksenii, Yersinia intermedia, or Yersinia enterocolitica). Twelve strains (3.2%) were misidentified or yielded codes with no identification; these comprised one Citrobacter amalonaticus (no identification), three Enterobacter hormaechei (not in the RapID onE database; two Enterobacter amnigenus, one Enterobacter sp.), one Serratia liquefaciens (Enterobacter cloacae), one Serratia rubidaea (no identification), four Serratia fonticola (not in RapID onE database; two Enterobacter aerogenes, one Serratia marcescens, one not identified), one Proteus mirabilis (Proteus penneri), and one Proteus vulgaris (Providencia rustigianii). If the seven strains not included in the database had been excluded, correct identification rates would have risen to 97.6% without additional tests and 98.7% with additional tests, with misidentification rates dropping to 1.3%. The RapID onE system is easy to set up and the results are easy to read, and the system provides an accurate, nonautomated commercially available method for the same-day identification of members of the family Enterobacteriaceae and oxidase-negative, gram-negative nonfermenters.
PMCID: PMC263165  PMID: 8027345
15.  Packed bed reactor for degradation of simulated cyanide-containing wastewater 
3 Biotech  2014;5(5):641-646.
The discharge of cyanide-containing effluents into the environment contaminates water bodies and soil. Effective methods of treatment which can detoxify cyanide are the need of the hour. The aim of the present study is to develop a bioreactor for complete degradation of cyanide using immobilized cells of Serratia marcescens RL2b. Alginate-entrapped cells of S. marcescens RL2b were used for complete degradation of cyanide in a packed bed reactor (PBR). Cells grown in minimal salt medium (pH 6.0) were harvested after 20 h and exhibited 0.4 U mg−1 dcw activity and 99 % cyanide degradation in 10 h. These resting cells were entrapped using 3 % alginate beads and packed in a column reactor (20 × 1.7 cm). Simulated cyanide (12 mmol l−1)-containing wastewater was loaded and fractions were collected after different time intervals at various flow rates. Complete degradation of 12 m mmol l−1 (780 mg l−1) cyanide in 10 h was observed at a flow rate of 1.5 ml h−1. The degradation of cyanide in PBR showed direct dependence on retention time. The retention time of cyanide in the reactor was 9.27 h. The PBR can degrade 1.2 g of cyanide completely in 1 day.
PMCID: PMC4569630
Serratia marcescens RL2b; Packed bed reactor; Cyanide; Retention time
16.  Size and UV Germicidal Irradiation Susceptibility of Serratia marcescens when Aerosolized from Different Suspending Media 
Experimental systems have been built in laboratories worldwide to investigate the influence of various environmental parameters on the efficacy of UV germicidal irradiation (UVGI) for deactivating airborne microorganisms. It is generally recognized that data from different laboratories might vary significantly due to differences in systems and experimental conditions. In this study we looked at the effect of the composition of the suspending medium on the size and UVGI susceptibility of Serratia marcescens in an experimental system built in our laboratory. S. marcescens was suspended in (i) distilled water, (ii) phosphate buffer, (iii) 10% fetal calf serum, (iv) phosphate-buffered saline (saline, 0.8% sodium chloride), and (v) synthetic saliva (phosphate-buffered saline with 10% fetal calf serum). At low humidity (36%), S. marcescens suspended in water-only medium was the most susceptible to UVGI, followed by those in serum-only medium. The count median diameters (CMDs) for culturable particles from water-only and serum-only media were 0.88 and 0.95 μm, respectively, with the measurements based on their aerodynamic behavior. The bacteria suspended in phosphate buffer, synthetic saliva, and phosphate-buffered saline had similar UVGI susceptibility and CMD at 1.0, 1.4, and 1.5 μm, respectively. At high humidity (68%) the CMD of the particles increased by 6 to 16%, and at the same time UVGI susceptibility decreased, with the magnitude of decrease related to the type of suspending medium. In conclusion, the choice of suspending medium influenced both size and UVGI susceptibility of S. marcescens. These data are valuable for making comparisons and deciding on the use of an appropriate medium for various applications.
PMCID: PMC383042  PMID: 15066792
17.  Serratia marcescens outbreak in a neonatal intensive care unit: crucial role of implementing hand hygiene among external consultants 
Serratia marcescens represents an important pathogen involved in hospital acquired infections. Outbreaks are frequently reported and are difficult to eradicate. The aim of this study is to describe an outbreak of Serratia marcescens occurred from May to November 2012 in a neonatal intensive care unit, to discuss the control measures adopted, addressing the role of molecular biology in routine investigations during the outbreak.
After an outbreak of Serratia marcescens involving 14 neonates, all admitted patients were screened for rectal and ocular carriage every two weeks. Extensive environmental sampling procedure and hand sampling of the staff were performed. Antimicrobial susceptibility pattern and molecular analysis of isolates were carried out. Effective hand hygiene measures involving all the external consultants has been implemented. Colonized and infected babies were cohorted. Dedicated staff was established to care for the colonized or infected babies.
During the surveillance, 65 newborns were sampled obtaining 297 ocular and rectal swabs in five times. Thirty-four Serratia marcescens isolates were collected: 11 out of 34 strains were isolated from eyes, being the remaining 23 isolated from rectal swabs. Two patients presented symptomatic conjunctivitis. Environmental and hand sampling resulted negative. During the fifth sampling procedure no colonized or infected patients have been identified. Two different clones have been identified.
Ocular and rectal colonization played an important role in spread of infections. Implementation of infection control measures, involving also external specialists, allowed to control a serious Serratia marcescens outbreak in a neonatal intensive care unit.
PMCID: PMC4301457  PMID: 25582674
Serratia marcescens; Outbreak; Neonatal intensive care unit; Molecular epidemiology; Ocular colonization; Rectal colonization; Hand hygiene
18.  Case‐control analysis of endemic Serratia marcescens bacteremia in a neonatal intensive care unit 
Serratia marcescens is an opportunistic gram‐negative rod which typically infects compromised hosts.
To identify risk factors, signs, and outcomes associated with non‐epidemic S marcescens bacteremia in a neonatal intensive care unit (NICU).
The records of infants with S marcescens bacteremia while in the Yale‐New Haven Hospital NICU from 1980–2004 were reviewed. A matched case‐control study was performed by comparing each case of S marcescens to 2 uninfected controls and 2 cases of Escherichia coli bacteremia.
Twenty‐five sporadic cases of S marcescens bacteremia were identified. Eleven available isolates were determined to be different strains by pulse field gel electrophoresis. Infants with S marcescens bacteremia had median gestational age and birth weight of 28 weeks and 1235 grams, respectively. Compared to matched, uninfected controls, infants with S marcescens bacteremia were more likely to have had a central vascular catheter (OR = 4.33; 95% CI (1.41 to 13.36)) and surgery (OR = 5.67; 95% CI (1.81 to 17.37)), and had a higher overall mortality (44% vs 2%; OR = 38.50; 95% CI (4.57 to 324.47)). Compared to E coli matched controls, infants with S marcescens bacteremia had later onset of infection (median of 33 days of life vs 10; p<0.001), prolonged intubation (OR = 5.76; 95% CI (1.80 to 18.42)), and a higher rate of CVC (OR = 7.77; 95% CI (2.48 to 24.31)) use at the time of infection. A higher rate of meningitis (24% vs 7%; OR = 3.98; 95% CI (1.09 to 14.50)) was observed with S marcescens bacteremia compared to E coli.
S marcescens bacteremia occurs sporadically in the NICU, primarily in premature infants requiring support apparatus late in their hospital course. Associated meningitis is common and mortality high.
PMCID: PMC2675455  PMID: 17088342
19.  Development of Quantitative Real-Time PCR Assays for Detection and Quantification of Surrogate Biological Warfare Agents in Building Debris and Leachate▿  
Applied and Environmental Microbiology  2007;73(20):6557-6565.
Evaluation of the fate and transport of biological warfare (BW) agents in landfills requires the development of specific and sensitive detection assays. The objective of the current study was to develop and validate SYBR green quantitative real-time PCR (Q-PCR) assays for the specific detection and quantification of surrogate BW agents in synthetic building debris (SBD) and leachate. Bacillus atrophaeus (vegetative cells and spores) and Serratia marcescens were used as surrogates for Bacillus anthracis (anthrax) and Yersinia pestis (plague), respectively. The targets for SYBR green Q-PCR assays were the 16S-23S rRNA intergenic transcribed spacer (ITS) region and recA gene for B. atrophaeus and the gyrB, wzm, and recA genes for S. marcescens. All assays showed high specificity when tested against 5 ng of closely related Bacillus and Serratia nontarget DNA from 21 organisms. Several spore lysis methods that include a combination of one or more of freeze-thaw cycles, chemical lysis, hot detergent treatment, bead beat homogenization, and sonication were evaluated. All methods tested showed similar threshold cycle values. The limit of detection of the developed Q-PCR assays was determined using DNA extracted from a pure bacterial culture and DNA extracted from sterile water, leachate, and SBD samples spiked with increasing quantities of surrogates. The limit of detection for B. atrophaeus genomic DNA using the ITS and B. atrophaeus recA Q-PCR assays was 7.5 fg per PCR. The limits of detection of S. marcescens genomic DNA using the gyrB, wzm, and S. marcescens recA Q-PCR assays were 7.5 fg, 75 fg, and 7.5 fg per PCR, respectively. Quantification of B. atrophaeus vegetative cells and spores was linear (R2 > 0.98) over a 7-log-unit dynamic range down to 101 B. atrophaeus cells or spores. Quantification of S. marcescens (R2 > 0.98) was linear over a 6-log-unit dynamic range down to 102 S. marcescens cells. The developed Q-PCR assays are highly specific and sensitive and can be used for monitoring the fate and transport of the BW surrogates B. atrophaeus and S. marcescens in building debris and leachate.
PMCID: PMC2075066  PMID: 17720820
20.  Iron transport systems of Serratia marcescens. 
Journal of Bacteriology  1992;174(4):1378-1387.
Serratia marcescens W225 expresses an unconventional iron(III) transport system. Uptake of Fe3+ occurs in the absence of an iron(III)-solubilizing siderophore, of an outer membrane receptor protein, and of the TonB and ExbBD proteins involved in outer membrane transport. The three SfuABC proteins found to catalyze iron(III) transport exhibit the typical features of periplasmic binding-protein-dependent systems for transport across the cytoplasmic membrane. In support of these conclusions, the periplasmic SfuA protein bound iron chloride and iron citrate but not ferrichrome, as shown by protection experiments against degradation by added V8 protease. The cloned sfuABC genes conferred upon an Escherichia coli aroB mutant unable to synthesize its own enterochelin siderophore the ability to grow under iron-limiting conditions (in the presence of 0.2 mM 2.2'-dipyridyl). Under extreme iron deficiency (0.4 mM 2.2'-dipyridyl), however, the entry rate of iron across the outer membrane was no longer sufficient for growth. Citrate had to be added in order for iron(III) to be translocated as an iron citrate complex in a FecA- and TonB-dependent manner through the outer membrane and via SfuABC across the cytoplasmic membrane. FecA- and TonB-dependent iron transport across the outer membrane could be clearly correlated with a very low concentration of iron in the medium. Expression of the sfuABC genes in E. coli was controlled by the Fur iron repressor gene. S. marcescens W225 was able to synthesize enterochelin and take up iron(III) enterochelin. It contained an iron(III) aerobactin transport system but lacked aerobactin synthesis. This strain was able to utilize the hydroxamate siderophores ferrichrome, coprogen, ferrioxamine B, rhodotorulic acid, and schizokinen as sole iron sources and grew on iron citrate as well. In contrast to E. coli K-12, S. marcescens could utilize heme. DNA fragments of the E. coli fhuA, iut, exbB, and fur genes hybridized with chromosomal S. marcescens DNA fragments, whereas no hybridization was obtained between S. marcescens chromosomal DNA and E. coli fecA, fhuE, and tonB gene fragments. The presence of multiple iron transport systems was also indicated by the increased synthesis of at least five outer membrane proteins (in the molecular weight range of 72,000 to 87,000) after growth in low-iron media. Serratia liquefaciens and Serratia ficaria produced aerobactin, showing that this siderophore also occurs in the genus Serratia.
PMCID: PMC206435  PMID: 1531225
21.  Pore-Forming Toxins Induce Macrophage Necroptosis during Acute Bacterial Pneumonia 
PLoS Pathogens  2015;11(12):e1005337.
Necroptosis is a highly pro-inflammatory mode of cell death regulated by RIP (or RIPK)1 and RIP3 kinases and mediated by the effector MLKL. We report that diverse bacterial pathogens that produce a pore-forming toxin (PFT) induce necroptosis of macrophages and this can be blocked for protection against Serratia marcescens hemorrhagic pneumonia. Following challenge with S. marcescens, Staphylococcus aureus, Streptococcus pneumoniae, Listeria monocytogenes, uropathogenic Escherichia coli (UPEC), and purified recombinant pneumolysin, macrophages pretreated with inhibitors of RIP1, RIP3, and MLKL were protected against death. Alveolar macrophages in MLKL KO mice were also protected during S. marcescens pneumonia. Inhibition of caspases had no impact on macrophage death and caspase-1 and -3/7 were determined to be inactive following challenge despite the detection of IL-1β in supernatants. Bone marrow-derived macrophages from RIP3 KO, but not caspase-1/11 KO or caspase-3 KO mice, were resistant to PFT-induced death. We explored the mechanisms for PFT-induced necroptosis and determined that loss of ion homeostasis at the plasma membrane, mitochondrial damage, ATP depletion, and the generation of reactive oxygen species were together responsible. Treatment of mice with necrostatin-5, an inhibitor of RIP1; GW806742X, an inhibitor of MLKL; and necrostatin-5 along with co-enzyme Q10 (N5/C10), which enhances ATP production; reduced the severity of S. marcescens pneumonia in a mouse intratracheal challenge model. N5/C10 protected alveolar macrophages, reduced bacterial burden, and lessened hemorrhage in the lungs. We conclude that necroptosis is the major cell death pathway evoked by PFTs in macrophages and the necroptosis pathway can be targeted for disease intervention.
Author Summary
Necroptosis is a pro-inflammatory mode of programmed cell death that is marked by the intentional disruption of host membranes and the release of pro-inflammatory cytosolic components into the milieu. Until just recently necroptosis was not appreciated to play a role during infectious disease. Herein, we demonstrate that alveolar macrophages exposed to the nosocomial pathogen Serratia marcescens undergo necroptosis and this leads to enhanced disease severity. We subsequently demonstrate that necroptosis is the principle mode of cell death experienced by macrophages following their exposure to bacteria that produce pore-forming toxins (PFTs). We dissect the molecular mechanisms by which PFTs induce necroptosis and demonstrate that loss of ion homeostasis at the cell membrane and mitochondrial damage result in ATP depletion and ROS generation that together are responsible. Finally, we demonstrate that inhibition of necroptosis by various means is protective against hemorrhagic pneumonia caused by S. marcescens.
PMCID: PMC4676650  PMID: 26659062
22.  The characterization of upper-room ultraviolet germicidal irradiation in inactivating airborne microorganisms. 
Environmental Health Perspectives  2002;110(1):95-101.
In this study, we explored the efficacy of upper-room ultraviolet germicidal irradiation (UVGI) in reducing the concentration of Serratia marcescens and Mycobacterium bovis bacille Calmette-Guérin (BCG) aerosols in enclosed places. We constructed a facility (4.5 m x 3 m x 2.9 m) in which both ceiling- and wall-mounted UV fixtures (UV output: 10W and 5W respectively) were installed. The use of ceiling- and wall-mounted UV fixtures (total UV output: 15W) without mixing fan reduced the concentration of S. marcescens aerosols by 46% (range: 22-80%) at 2 air changes per hour (ACH) and 53% (range: 40-68%) at 6 ACH. The use of ceiling- and wall-mounted UV fixtures with mixing fan increased the UV effectiveness in inactivating S. marcescens aerosols to 62% (range: 50-78%) at 2 ACH and to 86% (81-89%) at 6 ACH. For BCG aerosols, UV effectiveness in inactivating BCG aerosols at 6 ACH were 52% (range: 11-69%) by ceiling-mounted UV fixture only (total UV output: 10W) and 64% (51-83%) by both ceiling- and wall-mounted UV fixtures (total UV output: 15W). Our results indicated that the equivalent ventilation rate attributable to upper-room UVGI for BCG aerosols ranged from 1 ACH to 22 ACH for ceiling-mounted UV fixtures and from 6.4 ACH to 28.5 ACH for ceiling- and wall-mounted UV fixtures. Both generalized linear and generalized additive models were fitted to all our data. The regression results indicated that the number of UV fixtures, use of mixing fan, and air exchange rate significantly affected UV effectiveness (p < 0.01, 0.01, 0.01 respectively). However, the strain difference (S. marcescens vs. BCG) appeared less important in UV effectiveness (p = 0.26). Our results also indicated that UV effectiveness increased at higher temperature ((italic)p(/italic) < 0.01), lower dry-bulb temperature ((italic)p(/italic) = 0.21), and colder air from a supply grill located near the ceiling (p = 0.22).
PMCID: PMC1240698  PMID: 11781170
Journal of Bacteriology  1962;84(6):1297-1302.
Zimmerman, Leonard (U.S. Army Biological Laboratories, Fort Detrick, Frederick, Md.). Survival of Serratia marcescens after freeze-drying or aerosolization at unfavorable humidity. I. Effects of sugars. J. Bacteriol. 84:1297–1302. 1962.—Suspensions of Serratia marcescens were subjected to freeze-drying or to aerosolization at unfavorable humidity levels. The survival of the cells during one or the other of these treatments was markedly improved in the presence of common sugars, but no one sugar stabilized the cells against both stresses. The protective effects of the sugars were correlated with their penetrability into cells; minimally penetrable sugars stabilized cells against aerosolization, and freely penetrable sugars stabilized cells during freeze-drying. These results were attributed to the modifications of intracellular water content induced by the presence of the sugars in the cell suspensions.
PMCID: PMC278062  PMID: 14003706
24.  Effects of Lipid Emulsion and Multivitamins on the Growth of Microorganisms in Peripheral Parenteral Nutrition Solutions 
Background: Blood stream infections caused by Bacillus cereus or Serratia marcescens in patients receiving peripheral parenteral nutrition (PPN) have occasionally been reported in Japan, but these microorganisms are not major causes of blood stream infections in patients receiving total parenteral nutrition via a central venous catheter. In Japan, commercially available PPN solutions contain amino acids, glucose, and electrolytes, but not contain lipid emulsion (LE) and multivitamins (MV). In this study, the effects of LE and MV on the growth of microorganisms such as Bacillus cereus, Serratia marcescens, Staphylococcus aureus, and Candida albicans in PPN solutions were investigated. Methods: A commercial 3% amino acid and 7.5% glucose solution with electrolytes (AF) was used as the base solution to prepare test solutions (LAF, AFV, and LAFV) containing LE, MV, or both. Specifically, 20% LE was added to AF in a ratio of 1:9 to prepare LAF. MV was added to AF and LAF to prepare AFV and LAFV, respectively. A specified number of each microorganism was added to each 100 mL of AF, LAF, AFV, and LAFV in sterile plastic flasks, and all flasks were allowed to stand at room temperature. The number of colony forming units per mL of each microorganism was counted at 0, 24, and 48 hours after the addition of each microorganism. Results: Both Bacillus cereus and Serratia marcescens increased rapidly in AF as well as in LAF, AFV, and LAFV. Staphylococcus aureus did not increased in AF, but increased slightly in LAF and increased rapidly in AFV and LAFV. Candida albicans increased slightly in AF and increased rapidly in LAF, AFV, and LAFV. Conclusions: The results suggest the followings: if microbial contamination occurs, 1) Bacillus cereus and Serratia marcescens can grow rapidly in PPN solutions consisting of amino acids, glucose and electrolytes; 2) Staphylococcus aureus cannot grow without LE and MV, but can grow rapidly with MV; 3) Candida albicans can grow slowly without LE and MV, and the addition of LE or MV accelerates its growth.
PMCID: PMC3714382  PMID: 23869182
microbial growth; parenteral nutrition; lipid emulsion; multivitamins; PPN; BSI.
25.  Genetic Dissection of Anopheles gambiae Gut Epithelial Responses to Serratia marcescens 
PLoS Pathogens  2014;10(3):e1003897.
Genetic variation in the mosquito Anopheles gambiae profoundly influences its ability to transmit malaria. Mosquito gut bacteria are shown to influence the outcome of infections with Plasmodium parasites and are also thought to exert a strong drive on genetic variation through natural selection; however, a link between antibacterial effects and genetic variation is yet to emerge. Here, we combined SNP genotyping and expression profiling with phenotypic analyses of candidate genes by RNAi-mediated silencing and 454 pyrosequencing to investigate this intricate biological system. We identified 138 An. gambiae genes to be genetically associated with the outcome of Serratia marcescens infection, including the peptidoglycan recognition receptor PGRPLC that triggers activation of the antibacterial IMD/REL2 pathway and the epidermal growth factor receptor EGFR. Silencing of three genes encoding type III fibronectin domain proteins (FN3Ds) increased the Serratia load and altered the gut microbiota composition in favor of Enterobacteriaceae. These data suggest that natural genetic variation in immune-related genes can shape the bacterial population structure of the mosquito gut with high specificity. Importantly, FN3D2 encodes a homolog of the hypervariable pattern recognition receptor Dscam, suggesting that pathogen-specific recognition may involve a broader family of immune factors. Additionally, we showed that silencing the gene encoding the gustatory receptor Gr9 that is also associated with the Serratia infection phenotype drastically increased Serratia levels. The Gr9 antibacterial activity appears to be related to mosquito feeding behavior and to mostly rely on changes of neuropeptide F expression, together suggesting a behavioral immune response following Serratia infection. Our findings reveal that the mosquito response to oral Serratia infection comprises both an epithelial and a behavioral immune component.
Author Summary
In malaria vector mosquitoes, the presence of bacteria and malaria parasites is tightly linked. Bacteria that are part of the mosquito gut ecosystem are critical modulators of the immune response elicited during infection with malaria parasites. Furthermore, responses against oral bacterial infections can affect malaria parasites. Here, we combined mosquito gut infections with the enterobacterium Serratia marcescens with genome-wide discovery and phenotypic analysis of genes involved in antibacterial responses to characterize molecular processes that control gut bacterial infections thus possibly affecting the mosquito susceptibility to infection by malaria parasites. Our data reveal complex genetic networks controlling the gut bacterial infection load and ecosystem homeostasis. These networks appear to exhibit much higher specificity toward specific classes of bacteria than previously thought and include behavioral response circuits involved in antibacterial immunity.
PMCID: PMC3946313  PMID: 24603764

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