Cloacae Bacteremia Research Articles

Avatrombopag Safe and Effective in Treatment of Severe Refractory Thrombocytopenia in a Pediatric Patient with Philadelphia Chromosome Positive Acute Lymphoblastic Leukemia Following Allogeneic Hematopoietic Stem Cell Transplantation

Background: Persistent thrombocytopenia following allogeneic stem cell transplantation (alloHSCT) leads to an increase in morbidity and mortality. Causes of severe thrombocytopenia following HSCT include poor graft function, graft-versus-host disease (GVHD), infections, drug toxicities, underlying autoimmune diseases and relapse of underlying disease. Treatments can include thrombopoietin receptor agonists (TPO-RA), immunomodulators, and stem cell boost. Avatrombopag is a second generation TPO-RA approved for the treatment of primary chronic immune thrombocytopenia (ITP) in adult patients with poor response to standard treatments or in patients with chronic liver disease (CLD) associated thrombocytopenia requiring surgical interventions. Phase III clinical trials have shown greater platelet responses in chronic ITP and reduced transfusion needs in patients with CLD. Avatrombopag differs from other TPO-RA medications due to majority of elimination occurring in the gut, thus avoiding hepatic toxicity. Additionally, it does not require dietary restrictions. As there is limited literature in pediatric patients following alloHSCT, we describe the use of avatrombopag in a pediatric patient with chronic severe thrombocytopenia (<10 x10 3/uL) post HSCT. Objective: To describe the use of avatrombopag for severe refractory thrombocytopenia in a pediatric alloHSCT recipient. Case Presentation: We present a 14-year-old Hispanic male with Philadelphia chromosome positive acute lymphoblastic leukemia (Ph+ ALL) who received a maternal haploidentical HSCT with myeloablative conditioning and post-transplant cyclophosphamide. His post HSCT course was complicated by adenoviremia, hepatic variant GVHD, Enterobacter cloacae bacteremia and poor graft function. Seven months following HSCT, patient was found to be severely pancytopenic. Bone marrow morphology demonstrated 20-30% cellularity without evidence of leukemia relapse or GVHD. Lab evaluation was not consistent with transplant associated thrombotic microangiopathy. He received a stem cell boost for presumed poor graft function. Patient demonstrated partial response by resolution of neutropenia and anemia; however, severe thrombocytopenia persisted. Multiple bone marrow evaluations remained negative for disease with full donor chimerism and negative TCR clonality. CXCL9 was noted to be elevated at 4270 and Immature Platelet fraction was elevated at 8.8. Platelet antibodies remained negative and all findings consistent with persistent severe ITP. Multiple treatments including romiplostim; eltrombopag; high dose immune globulin (IVIG); rituximab; methylprednisolone; and decitabine were not successful in improving platelet count (Figure 1). Evaluation for severe thrombocytopenia remained negative. During the course of severe thrombocytopenia, patient required several hospitalizations for symptomatic thrombocytopenia, requiring multiple platelet transfusions. Due to the severity of disease, he was granted a compassionate use investigational new drug (IND 165837) for avatrombopag and began on day +332. Dosing was initiated at 20 mg daily with a dosage adjustment to achieve platelet recovery to >50 x10 3/uL free from transfusion. The dose was titrated per manufacturer to maximum dose of 40 mg daily with response to platelet count >100 x10 3/uL in approximately 6 weeks time. By three months of treatment, dose was titrated down 40 mg three times a week and 20 mg on alternating days. Patient continues to maintain platelets above 100 x10 3/uL with no medication toxicities or adverse events noted. Patient has been able to return to his pre-alloHSCT lifestyle including contact sports and re-immunizations.

Cefepime Dosing in a Critically Ill Neonate Receiving Continuous Renal Replacement Therapy With the Cardio-Renal Pediatric Dialysis Emergency Machine (CARPEDIEM).

We report on a former 27-week gestational age infant who was placed on the Cardio-Renal Pediatric Dialysis Emergency Machine (CARPEDIEM) at 4 months post-menstrual age while receiving cefepime treatment for an Enterobacter cloacae bacteremia and persistent peritonitis secondary to an infected peritoneal dialysis catheter. Using therapeutic drug monitoring while assessing the clearance of cefepime on continuous renal replacement therapy (CRRT), we were able to successfully treat this patient's infection while also minimizing the risk of side effects from this medication. Current literature supports dosing in adult patients on all modalities of CRRT with effluent flow rates of 20 to 25 mL/kg/hr; however, pharmacokinetic data on cefepime dosing in pediatric CRRT are scant. This case report describes the successful dosing strategy used for this patient while on various rates of continuous veno-venous hemodialysis with CARPEDIEM. Therapeutic drug monitoring of cefepime should be considered in critically ill pediatric patients on CARPEDIEM receiving CRRT.

Clinical characteristics and outcome of bacteraemia caused by Enterobacter cloacae and Klebsiella aerogenes: more similarities than differences

The genus Enterobacter is a common cause of nosocomial infections. Historically, the most frequent Enterobacter species were those of Enterobacter cloacae complex and Enterobacter aerogenes. In 2019, E. aerogenes was re-classified as Klebsiella aerogenes owing to its higher genotypic similarity with the genus Klebsiella. Our objective was to characterise and compare the clinical profiles of bacteraemia caused by E. cloacae and K. aerogenes. This 3-year multicentre, prospective cohort study enrolled consecutive patients with bacteraemia by E. cloacae or K. aerogenes. Baseline characteristics, bacteraemia features (source, severity, treatment), antibiotic susceptibility, resistance mechanisms and mortality were analysed. The study included 285 patients with bacteraemia [196 (68.8%) E. cloacae and 89 (31.2%) K. aerogenes]. The groups showed no differences in age, sex, previous use of invasive devices, place of acquisition, sources or severity at onset. The Charlson score was higher among patients with E. cloacae bacteraemia [2 (1-4) vs. 1 (0.5-3); P=0.018], and previous antibiotic therapy was more common in patients with K. aerogenes bacteraemia (57.3% vs. 41.3%; P=0.01). Mortality was 19.4% for E. cloacae and 20.2% for K. aerogenes (P = 0.869). Antibiotic susceptibility was similar for both species, and the incidence of multidrug resistance or ESBL production was low (6% and 5.3%, respectively), with no differences between species. Bacteraemias caused by E. cloacae and K. aerogenes share similar patient profiles, presentation and prognosis. Patients with E. cloacae bacteraemia had more co-morbidities and those with K. aerogenes bacteraemia had received more antibiotics.

Obstructive Jaundice Due to Duodenal Ulcer Induced by Lenvatinib Therapy for Hepatocellular Carcinoma

An 82-year-old man with hepatocellular carcinoma presented with upper abdominal pain, vomiting, and jaundice. He had been taking a standard lenvatinib dose for three months. Although acute cholangitis was suggested, imaging studies failed to detect the biliary obstruction site. An endoscopic examination following discontinuation of lenvatinib and aspirin revealed multiple duodenal ulcers, one of which was formed on the ampulla of Vater and causing cholestasis. Endoscopic biliary drainage and antibiotics improved concomitant Enterobacter cloacae bacteremia. Ulcer healing was confirmed after rabeprazole was replaced with vonoprazan and misoprostol. Our case shows that lenvatinib can induce duodenal ulcers resulting in obstructive jaundice.

Cluster Analysis and Genetic Characterization of Enterobacter cloacae Complex from Blood Cultures

Background: Enterobacter cloacae bacteremia is reported as an important cause of morbidity and mortality. The members of E. cloacae complex are clinically involved in nosocomial infections. Objectives: The purpose of this study was to investigate the prevalence of E. cloacae complex and its members in blood samples and conduct the hsp60 cluster analysis and genotyping of the isolates. Methods: Eight isolates of E. cloacae complex were collected from blood cultures of hospitalized patients during the study period (December 2012 to November 2013). The hsp60 sequencing was done for the genetic classification. Pulsed-field gel electrophoresis (PFGE) was used for genotyping of the isolates. Results: Fifty percent of the isolates belonged to two E. hormaechei subspecies. Three isolates (37.5%) clustered within genotype III while only one isolate fitted cluster XIII genotype (12.5%). Pulsed-field gel electrophoresis analysis revealed four different pulsotypes. Conclusions: Different E. cloacae complex species and subspecies unequally contribute to the pathogenesis of blood infections and the subspecies of E. hormaechei were found to be most prevalent. Moreover, the common E. cloacae pulsotypes were observed to essentially produce identical hsp60 sequence types, indicating the probable clonality of isolates with identical pulsotypes.

2429. The Epidemiology and Outcomes of Enterobacter cloacae Bloodstream Infections in Children

BackgroundBloodstream infections cause significant morbidity and mortality in children admitted to intensive care units (ICUs). Enterobacter cloacae bloodstream infections can be particularly challenging to treat given increasing antibiotic resistance and presence of inducible β-lactamases on some strains. The objective of this study was to describe the epidemiology and clinical outcomes for critically ill children with E. cloacae bloodstream infections.MethodsWe performed a retrospective cohort study of children ≤19 years hospitalized in the critical care unit at the Children National Medical Center in Washington, DC with E. cloacae bloodstream infections between 2007 and 2016. We excluded polymicrobial infections. We performed chart review to collect baseline characteristics, treatment regimens, and outcomes. Recurrence of infection was defined as new E. cloacae bacteremia within 30 days of discontinuing antibiotics for initial infection.ResultsTwenty-six episodes of E. cloacae bacteremia met inclusion criteria. Median age was 7 months (IQR 2–16 months), and 6/26 (23%) patients were African-American. All patients had at least one underlying chronic medical condition, the most common being neuromuscular (35%), end-stage renal disease (27%), oncologic (12%), and short bowel syndrome (15%). Central venous catheter was present in 18 (75%) patients and 10 (38%) had hemodynamic instability requiring vasopressor support at time of bacteremia. Seven isolates (27%) were not susceptible to third-generation cephalosporins. Antibiotic treatment varied, with 7 (27%) receiving carbapenems empirically within 72 hours. Mean duration of bacteremia was 2.9 days. Infection recurred within 30 days in 2 patients (8%) and 2 patients (8%) died within 30 days of the initial positive blood culture.ConclusionAll episodes of E. cloacae bacteremia occurring in children admitted to the ICU occurred in patients with underlying comorbid conditions, and more than half of affected children were infants <1 year. More than one-third of these infections were associated with severe sepsis and nearly one in ten infected patients died within one monthDisclosures All authors: No reported disclosures.

Detection of Curli Biogenesis Genes Among Enterobacter cloacae Isolated From Blood Cultures

Background: Enterobacter cloacae bacteremia infection is an significant cause of morbidity and mortality in both developing and developed countries. Curli fibrils are considered the most important virulence factor in these bacteria. Objectives: The purpose of this research was to detect curli biogenesis genes among Enterobacter cloacae isolated from blood cultures. Materials and Methods: Nine E. cloacae isolates were collected from blood cultures of inpatients admitted to three hospitals in the Tehran, Iran during December 2012 to November 2013. Confirmation of identity of the infecting organism as E. cloacae was performed by API20E system and the presence of a csgA and csgD genes by PCR using csgA and csgD specific primers. Results: All of E. cloacae bloodstream strains (100%) harbored csgD gene (curli biogenesis activator) and seven (77.75%) carried csgA gene (curli major subunit) which is indicative of wide distribution of this virulence factor among our isolates. Conclusions: Extensive presence of curli biogenesis genes (csgD and csgA) among E.cloacae strains and probably expression of those crucial role of this virulence factor in E. cloacae pathogenesis and invasiveness.

Cefepime Therapy for Monomicrobial Enterobacter cloacae Bacteremia: Unfavorable Outcomes in Patients Infected by Cefepime-Susceptible Dose-Dependent Isolates

A new category of cefepime susceptibility, susceptible dose dependent (SDD), for Enterobacteriaceae, has been suggested to maximize its clinical use. However, clinical evidence supporting such a therapeutic strategy is limited. A retrospective study of 305 adults with monomicrobial Enterobacter cloacae bacteremia at a medical center from 2008 to 2012 was conducted. The patients definitively treated with in vitro active cefepime (cases) were compared with those treated with a carbapenem (controls) to assess therapeutic effectiveness. The 30-day crude mortality rate is the primary endpoint, and clinical prognostic factors are assessed. Of 144 patients receiving definitive cefepime or carbapenem therapy, there were no significant differences in terms of age, sex, comorbidity, source of bacteremia, disease severity, or 30-day mortality (26.4% versus 22.2%; P = 0.7) among those treated with cefepime (n = 72) or a carbapenem (n = 72). In the multivariate analysis, the presence of critical illness, rapidly fatal underlying disease, extended-spectrum beta-lactamase (ESBL) producers, and cefepime-SDD (cefepime MIC, 4 to 8 μg/ml) isolates was independently associated with 30-day mortality. Moreover, those infected by cefepime-SDD isolates with definitive cefepime therapy had a higher mortality rate than those treated with a carbapenem (5/7 [71.4%], versus 2/11 [18.2%]; P = 0.045). Cefepime is one of the therapeutic alternatives for cefepime-susceptible E. cloacae bacteremia but is inefficient for cases of cefepime-SDD E. cloacae bacteremia compared with carbapenem therapy.

Prevalence of fecal carriage of extended-spectrum- and metallo-β-lactamase-producing gram-negative bacteria among neonates born in a hospital setting in central Saudi Arabia.

BACKGROUND AND OBJECTIVECommensal neonatal fecal flora constitute a reservoir of antibiotic resistance. The aim of this study was to characterize the prevalence of fecal carriage of extended spectrum beta-lactamases (ESBLs) and carbapenemase producing gram-negative bacteria among 150 neonates who were born in two hospitals in central Saudi Arabia.PATIENTS AND METHODSFrom June 2012 to Janauary 2013, 150 healthy neonates ≤7 days of age were screened for intestinal enteric bacteria colonization and the influence of age, mode of delivery, body weight and breast feeding of neonates on colonzation rates. The isolates were identified manually and by VITEK 2 and antibiotic susceptibility was tested. Phenotypic tests were performed to seek ESBL and metallo-β-lactamase (MBL) producers in recovered isolates.RESULTSAmong 150 fecal specimens, 188 gram-negative rods were recovered. E coli (n=130; 69.1%) was the commonest organism followed by Klebsiella pneumoniae (n=23; 12.2%), Pseudomonas aeuroginosa (n=14; 7.5%), Acinetobacter baumannii (n=9; 4.8%), Enterobacter spp. (n=9; 4.8%) and Morganella morganii (n=3; 1.6%). E coli colonization during the first day of life was 95.5% (n=43/45), which was relatively higher than in subsequent days. The colonization rate of E coli among low weight babies (≤3 kg) was significantly higher than fully grown neonates (≥4 kg)(P=.03). The prevalence of ESBL and MBL was 15.0% (n=28/188) and 1.6% (n=3/188). The prevalence rates of ESBL in E coli, K pneumoniae, E cloacae, M morganii and E aerogenes were 16.9% (n=22/130), 4.3 % (n=1/23), 60% (n=3/5), 33.3% (n=1/3), and 25% (n=1/4), respectively. All E cloacae with ESBLs and MBLs were resistant to all tested antibiotics including carbapenems.CONCLUSIONWithin the first week of life, the most important determinants of gut enteric bacteria composition in neonates were age in days, body weight, mode of delivery, and type of neonatal feeding. The findings of ESBLs- and MBLs-producing enteric bacteria as neonate-gut colonizers may have wider implication or linkage to prevention of nosocomial and community-acquired infections by these strains.

Dynamics of MDR Enterobacter cloacae outbreaks in a neonatal unit in Nepal: insights using wider sampling frames and next-generation sequencing.

ObjectivesThere are limited data on Enterobacter cloacae outbreaks and fewer describing these in association with NDM-1. With whole-genome sequencing, we tested the hypothesis that a cluster of 16 E. cloacae bacteraemia cases in a Nepali neonatal unit represented a single clonal outbreak, using a wider set of epidemiologically unrelated clinical E. cloacae isolates for comparison.MethodsForty-three isolates were analysed, including 23 E. cloacae and 3 Citrobacter sp. isolates obtained from blood cultures from 16 neonates over a 3 month period. These were compared with two contemporaneous community-associated drug-resistant isolates from adults, a unit soap dispenser isolate and a set of historical invasive isolates (n = 14) from the same geographical locality.ResultsThere were two clear neonatal outbreaks and one isolated case in the unit. One outbreak was associated with an NDM-1 plasmid also identified in a historical community-associated strain. The smaller, second outbreak was likely associated with a contaminated soap dispenser. The two community-acquired adult cases and three sets of historical hospital-associated neonatal isolates represented four additional genetic clusters.ConclusionsE. cloacae infections in this context represent several different transmission networks, operating at the community/hospital and host strain/plasmid levels. Wide sampling frames and high-resolution typing methods are needed to describe the complex molecular epidemiology of E. cloacae outbreaks, which is not appropriately reflected by routine susceptibility phenotypes. Soap dispensers may represent a reservoir for E. cloacae and bacterial strains and plasmids may persist in hospitals and in the community for long periods, sporadically being involved in outbreaks of disease.

Enterobacter cloacae septicaemia complicating rotavirus gastroenteritis: a case report

Rotavirus infections are a common cause of gastroenteritis in infants and young children worldwide. Although rotavirus gastroenteritis is usually self-limiting in healthy infants, approximately 33% of cases of severe diarrhoea require hospitalization (1). Small intestinal epithelium dysfunction during rotavirus gastroenteritis is well-documented. Enteric Gram-negative bacteraemia as a complication of rotavirus-associated gastroenteritis has been reported in healthy children (2). It is believed that steroid treatment for any purpose may increase the risk of invasion of the mucosa by endogenous enteric bacterial flora and gastrointestinal mucosal damage via rotavirus infection. There are only 2 reported cases of secondary enteric Gram-negative bacteraemia in infants with rotavirus infection who were treated with corticosteroids for panhypopituitarism and congenital adrenal hyperplasia (3). In this paper we report the case of a patient with nosocomial rotavirus-associated gastroenteritis complicated by Enterobacter cloacae bacteraemia who was treated with adrenocorticotrophic hormone (ACTH) for infantile spasm.

717Clinical characteristics and outcome of metallo-β-lactamase-producing Enterobacter cloacae bacteremia at a tertiary care cancer center in Japan

717Clinical characteristics and outcome of metallo-β-lactamase-producing Enterobacter cloacae bacteremia at a tertiary care cancer center in Japan

A Study of 5 Cases of Enterobacter cloacae Bacteremia Caused by Nosocomial Infection

A Study of 5 Cases of Enterobacter cloacae Bacteremia Caused by Nosocomial Infection

Comparison of the clinical and microbiologic characteristics of patients with Enterobacter cloacae and Enterobacter aerogenes bacteremia: a prospective observation study

We compared the characteristics and outcomes of 172 Enterobacter cloacae bacteremia and 67 Enterobacter aerogenes bacteremia (EAB) cases. Antimicrobial resistance rates to E. cloacae were higher than those to E. aerogenes. However, EAB more frequently presented as septic shock and was associated with poorer outcomes.

Pyléphlébite septique associée à une septicémie à Enterobacter cloacae

Septic pylephlebitis or purulent thrombosis of the portal venous system generally results from a progressive extension of suppurated thrombophlebitis, secondary to an intrabdominal infection. Germs most often found are Escherichia coli and Streptococcus, isolation of Enterobacter cloacae is unusual. We report a particular observation of septic pylephlebitis associated with E. cloacae bacteremia, without biliary, digestive or pancreatic lesion on the CT-scan. The antibiotic sensitivity pattern of the isolated germ and the negative epidemiologic investigation pled in favour of community acquired infection. The infection resolved with antibiotics and anticoagulation, followed by total repermeation of the portal system.

Disseminated fusariosis in a recipient of a bone-marrow transplant

A 58-year-old man, with acute myeloid leukaemia, had undergone matched-unrelated donor haemopoietic stem-cell transplantation a month before, and was hospitalised having not engrafted, with an Enterobacter cloacae bacteraemia. During hospitalisation, he developed multiple nodular skin lesions. His blood pressure was 154/94 mm Hg, pulse was 65 beats per min, temperature was 36·7°C, and respirations were 20 breaths per min. He had multiple erythematous mildly tender nodules on his abdomen, thorax, and extremities (figure, A).

Community-acquired bacteremia and acute cholecystitis due to Enterobacter cloacae: a case report

IntroductionEnterobacter cloacae is responsible for 65-75% of all Enterobacter infections, bacteremia being the most common syndrome. The majority of infections are nosocomially acquired and in patients with predisposing factors.Case presentationWe present a case of E. cloacae bacteremia secondary to acute cholecystitis in a 60-year-old man with recent diagnosis of cholelithiasis. The diagnosis was established with abdominal echography and positive blood and biliary cultures. The patient was managed successfully with cholecystectomy and antibiotic therapy.ConclusionThe peculiarity of our case is the development of community-acquired bacteremia due to E. cloacae with a clear infectious focus, as a single agent isolated in several blood cultures, in a patient without severe underlying diseases, prior antimicrobial use or previous hospital admission. Although the majority of Enterobacter spp. infections are nosocomially acquired, primary bacteremia being the most common syndrome, these pathogens may also be responsible for community-acquired cases. Patients without predisposing factors may also be affected.

Retrospective analysis of bacteremia because of Enterobacter cloacae compared with Escherichia coli bacteremia

A total of 52 patients of Enterobacter cloacae bacteremia from a University hospital during the period from January 2000 to June 2005 were analysed and compared with a reference group comprising 52 patients of Escherichia coli bacteremia. Overall, E. cloacae ranked the tenth in all pathogens of bacteremia accounting for 2.8% of the total patients. Although the incidence of E. cloacae bacteremia was low, the attributable mortality rate till achieved 13.5%. Most patients (86.5%) with E. cloacae bacteremia were hospital-acquired. The overwhelming majority of patients (92.3%) were men, while almost half of the patients (48.1%) were from the Department of Urological Surgery with underlying diseases such as urinal obstruction, kidney transplantation and kidney tumours. Possible risks factors associated with E. cloacae bacteremia included immunocompromised status, long-term hospitalisation and invasive procedures or surgeries. E. cloacae bacteremia significantly differed from E. coli bacteremia in a number of clinical aspects, including underlying diseases, portal of entry, infection type, risks factors, laboratory findings and appropriateness of empirical antibiotic therapy. Besides the high prevalence of resistance to cephalosporins, most E. cloacae blood isolates were also resistant to ciprofloxacin (resistance rate, 67.3%), gentamicin (73.1%) and tobramycin (73.1%). Based on the findings of the present study, E. cloacae is probably an important pathogen of bacteremia occurring in male patients with underlying urinal system illnesses.

Serratia marcescens bacteremia traced to an infused narcotic.

From June 30, 1998, through March 21, 1999, several patients in the surgical intensive care unit of a hospital acquired Serratia marcescens bacteremia. We investigated this outbreak. A case was defined as the occurrence of S. marcescens bacteremia in any patient in the surgical intensive care unit during the period of the epidemic. To identify risk factors, we compared patients with S. marcescens bacteremia with randomly selected controls. Isolates from patients and from medications were evaluated by pulsed-field gel electrophoresis. The hair of one employee was tested for fentanyl. Twenty-six patients with S. marcescens bacteremia were identified; eight (31 percent) had polymicrobial bacteremia, and seven of these had Enterobacter cloacae and S. marcescens in the same culture. According to univariate analysis, patients with S. marcescens bacteremia stayed in the surgical intensive care unit longer than controls (13.5 vs. 4.0 days, P<0.001), were more likely to have received fentanyl in the surgical intensive care unit (odds ratio, 31; P<0.001), and were more likely to have been exposed to two particular respiratory therapists (odds ratios, 13.1 and 5.1; P<0.001 for both comparisons). In a multivariate analysis, receipt of fentanyl and exposure to the two respiratory therapists (adjusted odds ratio for one therapist, 6.7; P=0.002; adjusted odds ratio for the other therapist, 9.5; P=0.02) remained significant. One respiratory therapist had been reported for tampering with fentanyl; his hair sample tested positive for fentanyl. Cultures of fentanyl infusions from two case patients yielded S. marcescens and E. cloacae. The isolates from the case patients and from the fentanyl infusions had similar patterns on pulsed-field gel electrophoresis. After removal of the implicated respiratory therapist, no further cases occurred. An outbreak of S. marcescens and E. cloacae bacteremia in a surgical intensive care unit was traced to extrinsic contamination of the parenteral narcotic fentanyl by a health care worker. Our findings underscore the risk of complications in patients that is associated with illicit narcotic use by health care workers.

Outbreak investigation of nosocomial enterobacter cloacae bacteraemia in a neonatal intensive care unit.

Over a period of 7 months, 23 patients hospitalized in a neonatal intensive care unit (NICU) developed nosocomial Enterobacter cloacae bacteraemia. Contaminated saline for preparing heparin solution was initially identified as the common source of E. cloacae bacteraemia. Although environmental sanitation was enforced, the outbreak continued. E. cloacae has always been isolated from various cultures of the environmental specimens, from the hands of personnel and from the faeces of patients. All of the 23 bacteraemic isolates and 8 stool isolates from infected infants, as well as the 17 isolates from environmental specimens were found to be of the same genotype using the polymerase chain reaction-based DNA fingerprinting method. After various infection control methods were instituted, the outbreak eventually came under control. For epidemiological investigation, 23 neonates without E. cloacae bacteraemia were matched for case-control study. Nineteen (83%) of the case-patients were premature. The significant risk factors leading to E. cloacae bacteraemia in the NICU included small gestation age, low birthweight, exposure to personnel with contaminated hands and the presence of E. cloacae in the stool carriage (p=0.003, 0.007, 0.018 and 0.040, respectively). The gastrointestinal tracts of the patients and environmental surfaces appeared to be the principal sites of bacterial reservoir. In conclusion, the outbreak of E. cloacae bacteraemia was caused by a particular strain and possibly via multiple modes of transmission, including a bottle of contaminated saline as an initial common source, endogenous spread from the gastrointestinal tract and successive cross-infections between patients, hands of personnel and the environment. Effective infection control requires a multidisciplinary approach and reinforcement of infection control procedures, including aseptic technique, hand washing, proper isolation and disinfection of environmental surfaces.