Marcescens Infection Research Articles

A comprehensive analysis of the defense responses of Odontotermes formosanus (Shiraki) provides insights into the changes during Serratia marcescens infection

BackgroundOdontotermes formosanus (Shiraki) is a highly damaging agroforestry pest. Serratia marcescens is a broad-spectrum insecticidal pathogen and is highly lethal to O. formosanus. However, little is known about the mechanism between them. To improve the biological control of pests, a more in-depth analysis of the interactions between the pests and the pathogens is essential.ResultsWe used RNA-seq, enzyme activity assays and real-time fluorescent quantitative PCR (qPCR) to explore the defense responses of O. formosanus against SM1. RNA-seq results showed that 1,160, 2,531 and 4,536 genes were differentially expressed at 3, 6 and 12 h after SM1 infection, and Kyoto Encyclopedia of Genes and Genomes (KEGG) results indicated that immune response and energy metabolism were involved in the defense of O. formosanus against SM1. Reactive oxygen species (ROS) levels and ROS synthesis genes were significantly elevated, and the antioxidant system were induced in O. formosanus after SM1 infection. In addition, the cellular immune genes were affected, and the Toll, immune deficiency (Imd), Janus kinase/signal transducer and activator of transcription (JAK/STAT), c-Jun N-terminal Kinase (JNK) and melanization pathways were activated. In vitro, Oftermicin, an antimicrobial peptide, had a significantly inhibitory effect on SM1. Furthermore, the expression levels and enzyme activities of phosphofructokinase (PFK), lactate dehydrogenase (LDH), succinate dehydrogenase (SDH) and isocitrate dehydrogenase (IDH) in glycolysis and tricarboxylic acid (TCA) cycles were increased.ConclusionsOur results clearly demonstrated that O. formosanus defended against SM1 by activating the antioxidant system, innate immunity and energy metabolism. This study would provide useful information for the development of biological controls of O. formosanus.

Serratia marcescens outbreak in a neonatal intensive care unit associated with contaminated handwashing sinks

PurposeThis article describes the origin of a S. marcescens outbreak in a neonatal intensive care unit (NICU). Materials and methodsA retrospective case-control study including 12 S. marcescens-positive and 22 S. marcescens-negative neonates in the NICU was performed to identify the source of the outbreak. S. marcescens isolates were collected during the outbreak and analyzed using whole-genome sequencing (WGS). IQ-Tree software, BEAST2 software package and SCOTTI software were used to construct a phylogenetic tree and a propagation path map. ResultsThe index case occurred on February 21st and outbreak ended on March 9th, 2021, affecting a total of 12 neonates (2 with S. marcescens infection and 10 with S. marcescens colonization). Multivariate logistic regression identified that the distance of <0.8 m between the bed unit and the sink (odds ratio [OR], 20.50; 95 % confidence interval [CI], 1.09–384.86), a large number of rotating nurses within a week (OR 2.58, 95 % CI, 1.09–6.11) and use of humidification water in the incubator (OR 189.70, 95 % CI, 2.76–13027.31) were significant increased risk factors for S. marcescens infection or colonization in the outbreak. WGS sifted out a predominant clone between contaminated handwashing sinks and patients, suggesting that cross-transmission was involved in the dissemination of S. marcescens. ConclusionContaminated handwashing sinks can be a communication intermediary of S. marcescens infection or colonization of neonates in the NICU. A distance of <0.8 m between the bed unit and the sink, and a large number of rotating nurses might play important roles in this outbreak. Attention should be paid to sinks contamination and contact transmission to prevent outbreaks.

Late Subcutaneous Infection Caused by Serratia marcescens Following Hyaluronic Acid Injection: A Case Report and Systemic Review.

The field of cosmetic filler injection has experienced rapid development over the past two decades, especially in facial augmentation utilizing hyaluronic acid (HA) fillers. Gram-negative bacteria are found to be the main pathogens of infective nodules after HA injection. The occurrence of cutaneous infections attributed to Serratia marcescens is exceedingly rare and predominantly noted in patients with compromised immune systems. To summarize the clinical features, diagnosis, and treatment of subcutaneous infection caused by Serratia marcescens following hyaluronic acid injection. A rare case of cutaneous Serratia marcescens infection following hyaluronic acid injection was presented. A comprehensive review of the published literature describing the management of skin infection caused by S. marcescens in immunocompetent patients was then conducted, which encompassed three case series and eight case reports published between 1999 and 2017. Data extraction included information on authors, gender, age, signs and symptoms, previous treatment, corresponding management strategies, and follow-up duration. Serratia marcescens were isolated in abscesses (n = 6, 35.29%), painful nodules (n = 2, 11.76%), ulcers (n = 6, 35.29%), and others (n = 3, 17.65%). In cases providing salvage plans (n = 11), quinolones were shown to be the most effective antibiotics for salvage, with eight full recoveries (72.73%), and trimethoprim-sulfamethoxazole was the second most useful antibiotic (18.18%). With the help of pathogen examination and drug-sensitive tests, sensitive aminoglycosides, quinolone (especially moxifloxacin), or TMP-SMX for at least 2 weeks can be considered as the first-line treatment of late subcutaneous infection caused by Serratia marcescens following hyaluronic acid injection.

Effects of two transglutaminases on innate immune responses in the oriental armyworm, Mythimna separata.

Transglutaminase (TGase) is a key enzyme that mediates hemolymph coagulation and is thought to contribute to the elimination of pathogenic microorganisms in invertebrates. The objective of this study was to elucidate the involvement of TGase in insect immune responses via functional analysis of this enzyme in the oriental armyworm, Mythimna separata,using recombinant proteins and RNA interference technique. We identified two TGase genes, mystgase1 and mystgase2, in Mythimna separata and found that both genes are expressed in all surveyed tissues in M. separata larvae. Significant changes were induced in hemocytes following Escherichia coli injection. Injection of Gram-positive bacteria (Micrococcus luteus) and Gram-negative bacteria (Escherichiacoli and Serratia marcescens) into larvae triggered a time-specific induction of both mystgase1 and mystgase2 in hemocytes. Recombinant MysTGase1 and MysTGase2 proteins bound to both E. coli and M. luteus, localizing within bacterial clusters and resulting in agglutination in a Ca2+-dependent manner. The hemocytes of larvae injected with recombinant MysTGase1 or MysTGase2 exhibited enhanced phagocytic ability against E. coli, improved in vivo bacterial clearance, and increased resistance to S. marcescens, decreasing larval mortality rate. Conversely, RNA interference targeting mystgase1 or mystgase2 significantly reduced hemocyte phagocytic capability, decreased bacterial clearance, and increased susceptibility to S. marcescens infection, thereby increasing larval mortality rate. The findings of this study are anticipated to expand our understanding of the function of TGases within insect immune responses and may contribute to developing new pest control strategies.

Organism-specific Trends in Carbapenem-resistant Enterobacterales Infections in a Cohort of Hospitalized Patients, 2012–2022

Background: Carbapenem-resistant Enterobacterales (CRE) infections are an urgent public health threat. An estimated 12,700 CRE (including E. coli, Klebsiella spp., and Enterobacter spp.) infections occurred in the United States in 2020. While the estimated incidence of CRE infections has been relatively stable between 2012 and 2020, organism-specific trends, including those for organisms not typically included in CRE surveillance definitions, have not been described. We estimated the annual rate of carbapenem-resistant Enterobacterales infections, disaggregated by organism, from 2012 to 2022. Methods: Data on inpatient hospitalizations from a dynamic cohort of short-term acute care hospitals reporting microbiology data between 2012 and 2022 were obtained from the PINC AI Database and the BD Insights Research Database. We included patients with clinical isolates of E. coli, Enterobacter spp., Klebsiella spp., Citrobacter spp., Serratia marcescens, Proteus mirabilis, and Morganella spp. and sufficient susceptibility results to identify carbapenem resistance. We limited our analysis to incident isolates, defined as a patient’s first isolate of a given organism and carbapenem resistance phenotype in a 14-day period. We calculated the annual rate of carbapenem-resistant infections per 10,000 hospitalizations for each organism. Results: There were 3,018,792 incident isolates from 55.8 million hospitalizations included in the analysis. Overall, 31,226 incident carbapenem-resistant isolates were identified. The rate of carbapenem-resistant infections varied by organism and over time (Table 1). The rate of carbapenem-resistant Klebsiella spp. infections appeared to decline from 3.94 in 2012 to 2.44 infections per 10,000 hospitalizations in 2022. The rate of carbapenem-resistant Enterobacter spp. infections appeared to increase from 1.05 in 2012 to 1.44 infections per 10,000 hospitalizations in 2022. The rate of carbapenem-resistant E. coli infections also appeared to increase, from 0.61 in 2012 to 0.85 infections per 10,000 hospitalizations in 2022. Rates of carbapenem-resistant Proteus mirabilis, Morganella spp., Citrobacter spp., or Serratia marcescens infections were similar in 2022 compared to 2012. Conclusions: Disaggregating data by organism revealed heterogeneous trends, with apparent increases in rates of carbapenem-resistant Enterobacter spp. and E. coli infections and apparent decreases in rates of carbapenem-resistant Klebsiella spp. infections. Organism-specific CRE analyses may provide additional insight into CRE epidemiology.

Pink colored breast milk! Serratia marcescens infection, series of 4 cases.

Pink coloration of breast milk is uncommon and it´s associated with colonization by Serratia marcescens, which is most frequently isolated in intensive care settings. Misinterpretation of the pink coloration may lead to premature cessation of breastfeeding. The objective is to present four cases of pink discoloration. Two retrospective and two prospective cases of pink discoloration in breast milk are described, which were reported to the lead author. Four healthy mother-infant pairs with documented pink discoloration are presented. S. marcescens was isolated from breast milk samples. All four infants were asymptomatic and underwent enterobacteria cultures. The mothers received outpatient antibiotic treatment, and two infants received treatment as well. Subsequent cultures yielded negative results, and the pink discoloration ceased. All mothers successfully resumed breastfeeding. There are very few reported cases of pink breast milk in the global literature. Colonization by S. marcescens is not an indication for discontinuation of breastfeeding.

Secondary serratia marcescens infection in tinea capitis in children with kerion manifestation

Secondary serratia marcescens infection in tinea capitis in children with kerion manifestation

Current Epidemiological Status and Antibiotic Resistance Profile of Serratia marcescens.

The spread of antibiotic resistance represents a serious worldwide public health issue, underscoring the importance of epidemiology research in determining antimicrobial strategies. The purpose of this research was to investigate antibiotic resistance in Serratia marcescens isolates from clinical samples over seven years at the University Hospital "San Giovanni di Dio e Ruggi d'Aragona" in Salerno, Italy. S. marcescens is an important opportunistic pathogen associated with a wide spectrum of clinical diseases, including pneumonia, keratitis, meningitis, and urinary tract and wound infections. Outbreaks of nosocomial infections by S. marcescens strains have been documented in high-risk settings, mainly affecting immunocompromised patients and newborns. The primary objective of this study is to assess the rates of antibiotic resistance over the years to deal with a future emergency which includes the failure of various therapies due to antibiotic resistance. During the investigation, a total of 396 species of S. marcescens were isolated from various clinical samples, mainly from broncho-aspirates and sputum (31.6%) and blood cultures (21.5%). Antibiotics that showed the greatest susceptibility included ceftazidime/avibactam, amikacin, trimethoprim/sulfamethoxazole, and selected members of the cephalosporin class. However, a disconcerting trend of increasing rates of carbapenem resistance was outlined over the observation period. The absence of effective countermeasures, combined with growing antibiotic resistance that negates the effectiveness of multiple antibiotics, highlights the potential for S. marcescens infections to trigger serious clinical complications and increased mortality rates. The surveillance of Serratia marcescens infections constitutes a pivotal element in refining empiric therapy to mitigate the dissemination of antimicrobial resistance.

Importance of core microRNA pathway genes and microRNAs associated with the defense of Odontotermes formosanus (Shiraki) against Serratia marcescens infection

MicroRNAs (miRNAs) are noncoding small regulatory RNAs involved in diverse biological processes. Odontotermes formosanus (Shiraki) is a polyphagous pest that causes economic damage to agroforestry. Serratia marcescens is a bacterium with great potential for controlling this insect. However, knowledge about the miRNA pathway and the role of miRNAs in O. formosanus defense against SM1 is limited. In this study, OfAgo1, OfDicer1 and OfDrosha were differentially expressed in different castes and tissues. SM1 infection affected the expression of all three genes in O. formosanus. Then, we used specific double-stranded RNAs to silence OfAgo1, OfDicer1 and OfDrosha. Knockdown of these genes enhanced the virulence of SM1 to O. formosanus, suggesting that miRNAs were critical in the defense of O. formosanus against SM1. Furthermore, we sequenced miRNAs from SM1-infected and uninfected O. formosanus. 33 differentially expressed (DE) miRNAs were identified, whereby 22 were upregulated and 11 were downregulated. Finally, the miRNA-mRNA networks were constructed, which further suggested the important role of miRNAs in the defense of O. formosanus against SM1. Totally, O. formosanus miRNA core genes defend against SM1 infection by regulating miRNA expression. This study elucidates the interactions between O. formosanus and SM1 and provides new theories for biological control.

Rare post-operative intracranial abscess due to Serratia marcescens: what we can learn from it?

BackgroundNosocomial infections caused by Serratia marcescens mostly occurred in pediatrics and it was very rarely reported after adult surgery. Here, an intracranial abscess caused by Serratia marcescens was reported.Case summaryWe report a rare case of a postoperative intracranial abscess caused by Serratia marcescens in a 63-year-old male patient with a left parietal mass. The patient underwent resection of the mass on June 1, 2022, and the postoperative pathology revealed an angiomatous meningioma, WHO I. He then experienced recurrent worsening of right limb movements, and repeated cranial CT scans showed oozing blood and obvious low-density shadows around the operation area. Delayed wound healing was considered. Subsequently, a large amount of pus was extracted from the wound. The etiological test showed that Serratia marcescens infection occurred before the removal of the artificial titanium mesh. Antibiotics were initiated based on the results of drug susceptibility tests. At present, the patient is recovering well and is still closely monitored during follow-up.ConclusionIt is rare for Serratia marcescens to cause brain abscesses without any obvious signs of infection. This report provided in detail our experience of a warning postoperative asymptomatic brain abscess caused by an uncommon pathogen.

A preliminary exploration on the mechanism of the carbapenem-resistance transformation of Serratia marcescens in vivo

BackgroundThe infection of carbapenem-resistant organisms was a huge threat to human health due to their global spread. Dealing with a carbapenem-resistant Serratia marcescens (CRSM) infection poses a significant challenge in clinical settings. This study aims to provide insights into strategies for controlling CRSM infection by exploring the transformation mechanism of carbapenem-resistance.MethodsWe used whole genome sequencing (WGS) to investigate the mechanism of carbapenem resistance in 14 S. marcescens isolates in vivo. The expression level of related genes and the minimum inhibitory concentration of meropenem (MICMEM) were also evaluated to confirm the mechanism of carbapenem resistance.ResultsSeven groups of S. marcescens, each consisting of two strains, were collected from a hospital and displayed a shift in MICMEM from low to high levels. Homology analysis revealed that the isolates in five groups were significantly different from the remaining two. WGS and experimental evidence indicated that four groups of strains developed carbapenem resistance by acquiring the blaKPC (obtaining group), while two groups (persisting group) increased the expression level of the blaKPC. In contrast, isolates in the last group (missing group) did not carry the blaKPC. All strains possessed multiple β-lactamase genes, including blaCTX−M−14, blaSRT−1, and blaSRT−2. However, only in the missing group, the carbapenem-resistant strain lost an outer membrane protein-encoding gene, leading to increased blaCTX−M−14 expression compared to the carbapenem-susceptible strain.ConclusionThe study findings suggest that S. marcescens strains developed diverse carbapenem resistance in vivo through the evolution of drug resistance, rather than through clone replacement. We hypothesize that carbapenem resistance in S. marcescens was due to certain clonal types with a distinct mechanism.

Association Between Serratia marcescens Contamination and Hygiene Compliance in Orthokeratology.

Given the characteristics of Serratia marcescens (S. marcescens), this study aimed at investigating its presence in the hands and contact lens cases of orthokeratology wearers, along with the status of bacterial contamination. The 39 patients received the questionnaires about the background of orthokeratology and hygiene habits. A total of 39 contact lens cases and 39 hand samples from the patients were collected at Show Chwan Memorial Hospital from June to August in 2020 and sent to National Chung Cheng University for DNA extraction and PCR identification. The results indicated a detection rate of 5.13% for S. marcescens in the contact lens cases and 12.82% in the hand samples. Additionally, 66.67% of contact lens case samples and 30.77% of hand samples found positive for 16s bacterial amplicons. The relationship between hand contamination and the duration of contact lens usage were revealed for both S. marcescens (p=0.021) and 16s bacterial amplicons (p=0.048). The results indicated that hand hygiene is more critical than focusing on contact lens hygiene when it comes to preventing S. marcescens infections. Nevertheless, both proper hand and contact lens hygiene practices can reduce the detection of bacterial eye pathogens, especially a common intestinal bacterium.

Outbreak of Serratia marcescens in the Neonatal Intensive Care Unit of a Tertiary Care Hospital in Mexico.

We describe an outbreak of Serratia marcescens (S. marcescens) infection in the neonatal intensive care unit at Women's Hospital in Sinaloa, Mexico. In April 2021, an outbreak of S. marcescens infection was identified. A case was identified as any patient who tested positive for S. marcescens and showed signs of an infectious process. S. marcescens was isolated from the blood cultures of 15 neonates with clinical signs of neonatal sepsis. Statistical analysis showed that all neonates had an invasive medical device. The problem was controlled after hospital hygiene and sanitation measures were strengthened. The study provides evidence of an outbreak of nosocomial bacteremia due to the cross-transmission of S. marcescens. The findings highlight the need for hospitals to implement strict hygiene measures, especially regarding hand washing, to prevent future outbreaks.

History and Presence of Serratia marcescens

Serratia marcescens is an important member of the order Enterobacterales, even though it was initially considered to be slightly virulent. Today it is an indisputable fact that Serratia is an important opportunistic pathogen responsible for a wide range of nosocomial infections. The main risk group is immunocompromised patients, both adults and newborns, and patients after different medical interventions such as bronchoscopy, central venous catheterization, urinal catheters, surgical drainage, tracheostomy, and mechanical ventilation. This species is documented as a causative agent of a variety of infections with different clinical presentations – bloodstream infections, respiratory and urinary tract infections, wound infections, and skin and soft tissue infections. In addition, S. marcescens is of high significance as an opportunistic pathogen due to its antibiotic resistance, which makes the treatment difficult. The types and the epidemiology of S. marcescens infections are presented and discussed in detail in this review.

Cladosporium sphaerospermum extract inhibits quorum sensing associated virulence factors of Serratia marcescens

Serratia marcescens is now becoming a propensity for its highly antimicrobial-resistant clinical infections. Currently, it provides a novel strategy to prevent and control microbial infection by regulating S. marcescens quorum sensing (QS). Deep-sea-derived fungi are rich in QS bioactive constituents. In this work, the extracts from Cladosporium sphaerospermum SCSGAF0054 showed potent QS-related virulence factors and biofilm-inhibiting activities against S. marcescens NJ01. The swimming motility and multiple virulence factors such as prodigiosin, exopolysaccharide (EPS), lipase, protease and hemolysin were moderately inhibited by the extracts at varied concentrations. The confocal laser scanning microscope (CLSM) and scanning electron microscope (SEM) images revealed that C. sphaerospermum extracts moderately arrested biofilm formation and cell viability. Further, real-time quantitative PCR (RT-qPCR) analysis revealed that expressions of genes associated with virulence factors, flhD, fimA, fimC, bsmA, bsmB, pigA, pigC, and shlA, were significantly down-regulated compared with control. In addition, the extracts combined with imipenem inhibited the QS system of S. marcescens NJ01, disrupted its preformed biofilm, released the intra-biofilm bacteria and killed the bacteria gradually. Therefore, the extracts combined with imipenem can partially restore bacterial drug sensitivity. These results suggest that the extracts from SCSGAF0054 effectively interfere with the QS system to treat S. marcescens infection alone or combining with classical antimicrobial drugs.

Predictors of Positive Repeat Blood Cultures in Patients With Gram-Negative Bacilli Bacteremia

Introduction Bloodstream infections occur commonly in the United States and are associated with significant morbidity and mortality. Bacteremia caused by gram-positive organisms has established guidelines for the use of follow-up blood cultures (FUBCs), whereas the use of FUBCs in bacteremia due to gram-negative bacilli (GNBs) does not. One study showed that positive FUBCs were more common in gram-positive coccus bacteremia (21%) than in GNB bacteremia (6%), calling into question the overall clinical utility of using FUBCs in GNB bacteremia. We investigated the factors associated with positive FUBCs in patients with GNB bacteremia in our institution to better guide clinical practice. Methods We used a case-control design for this study. We included patients 18 years or older admitted to our hospitals between January 1, 2014, and December 31, 2018, for a duration of ≥24 hours and who had a positive blood culture (BC) for GNB. Cases were defined as any patient with a positive FUBC drawn ≥24 hours after the initial positive BC. Control subjects were defined as patients with a negative FUBC after an initial positive BC. Characteristics of cases and control subjects were compared using descriptive statistics. A multivariable regression model using stepwise variable selection was used to identify factors significantly associated with having a positive FUBC. Results We identified 70 cases meeting the inclusion criteria. We compared these 70 cases with 528 control subjects. The cases and control subjects did not differ significantly in age, sex, race, or other predefined comorbid conditions. Significant predictors for having a positive FUBC included (1) organism resistance to initial antibiotic therapy (odds ratio [OR], 3.26; P = 0.035), (2) glomerular filtration rate less than 30 mL/min (OR, 2.35; P = 0.010), (3) initial admission to critical care unit (OR, 1.72; P = 0.049), (4) central line–associated infection (OR, 3.99; P = 0.004), (5) Klebsiella group infection (OR, 2.18; P = 0.015), and (6) Serratia marcescens infection (OR, 3.53; P = 0.037). Initial discordant BC was a negative predictive factor (OR, 0.44; P = 0.018). Follow-up blood culture drawn more than 48 hours after the initial positive BC had a lower likelihood of being positive than those drawn 24 to 48 hours after the initial BC (OR, 0.59; P = 0.037). Discussion We identified 6 independent risk factors for positive FUBCs as delineated previously. These factors provide guidance for further research and for future guideline development. The timing of the FUBCs had a significant impact on positivity. Follow-up blood cultures in GNB bacteremia should be obtained more than 48 hours after the initial positive BC.

Arare Serratia marcescens-associated acute endocarditis of atricuspid valve in an intravenous drug user : Acase report and literature review.

Serratia marcescens is agram-negative bacillus that is an opportunistic agent in respiratory tract infections, urinary tract infections, and septicemia. It is rarely also acause of infective endocarditis which follows arapid and devastating course, typically in persons with history of intravenous drug use (IDU). This article reports afatal case of a27-year-old patient with aknown history of IDU, who presented with clinical symptoms concerning right-sided endocarditis as well as signs of acute respiratory distress syndrome. Finally, adetailed review of the literature is provided concerning the acute endocarditis of atricuspid valve, especially associated with Serratia marcescens infection.

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

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

Epidemiology of Serratia marcescens infections in NICU of a Teaching and Research Hospital in Northern Italy.

Serratia marcescens (Sm) is a known cause of infection and colonization in neonates receiving intensive care. The aim of this study was to identify the risk factors for colonization and infection with Sm in Neonatal Intensive Care Unit (NICU) of a tertiary care Hospital. A case-control study was conducted from January to December 2011 in neonates admitted to the NICU. Cases are patients with a microbiologically confirmed infection or colonization, controls were randomly chosen among patients admitted to the same NICU. Globally, 39 acquired infections or colonizations were identified. Among factors related to pregnancy, only premature delivery was independently associated to the risk of infection; as well as mechanical ventilation and catheterization for parenteral nutrition, considering indwelling devices. Prolonged administration with antibiotics were also related to the risk of infection. Among Sm strains which have been tested to antibiotics, all have been resistant to amoxicillin/clavulanic acid and to colistin. This study confirms the association between Sm infection or colonization and low gestational age. Invasive medical devices and medications, strictly necessary in care-support of preterm neonates, are likely related to Sm infection too. Preventive control strategies are expected to be effective in the control of Sm spread in NICUs.

SERRATIA MARCESCENSBACTERAEMIA IN PRETERM NEONATE - A CASE REPORT

Background: Serratia marcescenshas emerged as opportunist in increasing number of hospital-associated infections in neonatal intensive care unit (NICUs), particularly as bloodstream infections. It is known to cause outbreaks in the NICUs, with high mortality rate in the vulnerable preterm population. Case presentation: We present a case of one and half month-old preterm neonate who had complaints of intolerance to feeding and failure to thrive. Clinical investigation revealed anaemia and increased inflammatory markers. Blood culture showed growth ofS marcescens.In antimicrobial susceptibility testing, the isolate showed susceptibility to all β-lactams, aminoglycosides and sulfamethoxazole-trimethoprim, but treatment failure occurred with empirical amikacin and piperacillin-tazobactam. Institution of meropenem showed good response. Discussion: In premature babies with very low birth weight along with prolonged NICU stay predisposed them to S marcescens infection. The capacity of S marcescens to resist antibiotic therapy in vivo in spite of the in vitro sensitivity was exemplified in our case. Conclusion: This case study portrays the important feature of S marcescens to develop in-vivo resistance despite being sensitive by in vitro testing which led to therapeutic failure. Carbapenem could be a choice in such treatment failure cases due S marcescens.