Enterobacter cloacae

A bacteria found in the feces of humans and other animals and in sewage, soil, and water.

It is occasionally found in urine and pus and in other pathologic materials from animals.

Species of the genus Enterobacter.

Other members of this family include Klebsiella, Escherichia, Citrobacter, S2242atia, Salmonella, and Shigella species.

A serious cause of nosocomial infection.

Gram-negative, facultatively anaerobic, rod-shaped bacteria that occurs in water, sewage, soil, meat, hospital environments, and on the skin and in the intestinal tract of man and animals as a commensal.

Bacteria with an outer membrane that contains lipopolysaccharides from which lipid-A plays a major role in sepsis.

Lipid-A, endotoxin, is the major stimulus for the release of cytokines, which are the mediators of systemic inflammation and its complications.

All Enterobacteriaceae ferment glucose and are able to grow in aerobic and anaerobic cultures.

MacConkey agar is a lactose-containing medium that is selective for nonfastidious gram-negative bacilli such as Enterobacteriaceae.

Responsible for various infections, including bacteremia, lower respiratory tract infections, skin and soft-tissue infections, urinary tract infections, endocarditis, intra-abdominal infections, septic arthritis, osteomyelitis, and ophthalmic infections.

Enterobacter species can also cause various community-acquired infections, including UTIs, skin and soft-tissue infections, and wound infections.

Risk factors for nosocomial Enterobacter infections include recent hospitalization, exposure to invasive procedures in the previous 72 hours, treatment with antibiotics in the past 30 days, and the presence of a central venous catheter.

These agents cause significant morbidity and mortality and resistance to multiple antibiotics.

Enterobacter species possess inducible beta-lactamases.

Third-generation cephalosporins should be avoided because resistance can quickly appear.

Rarely cause disease in healthy individuals.

An opportunistic pathogen that possesses an endotoxin known to play a major role in the pathophysiology of sepsis and its complications.

Community-acquired Enterobacter infections are occasionally seen.

Patients most susceptible to such infections are those who stay in the hospital and especially the ICU for prolonged periods.

Major risk factors of Enterobacter infection exposure to antimicrobial agents, malignancy, hepatobiliary disease, gastrointestinal ulcers, presence of intravenous catheters, burns, mechanical ventilation, and immunosuppression.

Source of infection may be endogenous or exogenous to the patient as the species is ubiquitous.

Healthcare personnel, healthcare equipment, and parenteral fluids can be the source of infections.

Enterobacter species contain a subpopulation of organisms that produce a beta-lactamase at low-levels, and follwing exposure to broad-spectrum cephalosporins, this subpopulation predominates.

Carbapenems and cefepime have a more stable beta-lactam ring against the lactamase produced by resistant strains of Enterobacter.

Second most common gram-negative nosocomial organism behind Pseudomonas aeruginosa.

Represents 4.7% of bloodstream infections in ICU settings.

Enterobacter species represent 3.1% of bloodstream infections in non-ICU hospital units.

Enterobacter species comprised 13.5% of the 75,000 gram negative isolates from ICU’s between 1993-2004.

Enterobacter species to be the eighth most common cause of healthcare facility associated infections and the fourth most common gram-negative cause of healthcare facility associated infections.

National Nosocomial Infections Surveillance System (NNIS) demonstrated that Enterobacter species caused 11.2% of pneumonia cases in ICUs, ranking third after Staphylococcus aureus and P aeruginosa.

Among pediatric patients in ICUs Enterobacter species isolated in 9.8% of pneumonias, 6.8% of bloodstream infections, and 9.5% for UTIs.

Enterobacter species among the most frequent pathogens involved in surgical site infections.

The Intensive Care Antimicrobial Resistance Epidemiology (ICARE) surveillance report revealed the rates of Enterobacter resistance to third-generation cephalosporins were 25.3% in ICUs, 22.3% among non-ICU inpatients, 10.1% among ambulatory patients, and as high as 36.2% in pediatric ICUs.

Most important factor in determining the risk of mortality of an Enterobacter infection is the severity of the underlying disease.

Outcome of Enterobacter infections associated with the presence of shock, presence of bacteremia, pneumonia, renal insufficiency, ICU presence, previously surgery, thrombocytopenia, presence of hemorrhage, intravascular and or urinary catheters, previous surgery, neutropenia, immunosuppressice therapy, and antibiotic resistance.

Empirical aminoglycoside use and appropriate initial antibiotic therapy were associated with lower mortality rates.

Risk factors for mortality included cephalosporin resistance, trimethoprim-sulfamethoxazole resistance, mechanical ventilation, and nosocomial infection.

Mortality rates associated with Enterobacter infections range from 15-87%, with most reported rates range from 20-46%.

Of all Enterobacter infections, E cloacae infection is associated with the highest mortality rate.

Enterobacteremia with cephalosporin resistant organisms is associated with a 30-day mortality rate that significantly exceeds that of infections with susceptible strains (33.7% vs 18.6%).

Enterobacter pneumonia associated with a higher mortality rate than pneumonia due to many other gram-negative bacilli.

Mortlaity rate from Enterobacter pneumonia ranges from 14-71%.

Enterobacter endocarditis has an overall mortality rate of about 44%.

Infections have no racial predilection.

Male-to-female ratio of bacteremia is 1.3-2.5:1.

Enterobacter infections are most common in neonates and in elderly individuals.

Enterobacter sakazakii has been reported as a cause of sepsis and meningitis, complicated by ventriculitis, brain abscess, cerebral infarction, and cyst formation, and has also been associated with contaminated powdered formula for infants.

Enterobacter cloacae, followed by E aerogenes, are implicated most frequently in Enterobacter bacteremia cases.

Mixed bacteremia is common.

Previous antibiotic exposure may predispose to Enterobacter pneumonia, as may chronic obstructive pulmonary disease, diabetes mellitus, alcoholism, malignancy, and neurologic disease.

Enterobacter species are a significant cause of ventilator-associated pneumonia, post-lung transplant pneumonia.

Enterobacter skin and soft-tissue infections are hospital-acquired and include cellulitis, fasciitis, myositis, abscesses, and wound infections.

There is a trend that traditional wound infections with Staphylococci is being replaced by Enterobacter species and other nosocomial pathogens

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