Enterococcus Infections in Children
Introduction to Enterococcus Infections in Children
Enterococci are gram-positive, facultatively anaerobic bacteria that are part of the normal intestinal flora in humans. While generally considered commensal organisms, enterococci can cause significant infections, particularly in healthcare settings and in immunocompromised individuals. In children, enterococcal infections pose unique challenges due to their increasing prevalence and antibiotic resistance patterns.
The two most clinically relevant species in this group are:
- Enterococcus faecalis (responsible for about 80-90% of enterococcal infections)
- Enterococcus faecium (responsible for most of the remaining infections)
These organisms have emerged as important nosocomial pathogens, particularly in pediatric intensive care units and among immunocompromised children. Understanding enterococcal infections in children is crucial for effective management and prevention of healthcare-associated complications.
Epidemiology of Enterococcus Infections in Children
Enterococcal infections have become increasingly significant in pediatric populations, particularly in specific settings:
- Neonatal Intensive Care Units (NICUs): Enterococci are a common cause of late-onset sepsis in premature infants.
- Pediatric Intensive Care Units (PICUs): Higher rates of enterococcal infections are seen in critically ill children.
- Oncology and Transplant Units: Immunocompromised children are at increased risk for enterococcal infections.
Factors contributing to the increasing prevalence of enterococcal infections include:
- Widespread use of broad-spectrum antibiotics, leading to selection of resistant strains
- Increased use of invasive procedures and indwelling devices
- Prolonged hospital stays, especially in intensive care settings
- Rising prevalence of vancomycin-resistant enterococci (VRE)
Studies have shown that enterococci account for a significant proportion of healthcare-associated infections in children, including bloodstream infections, urinary tract infections, and surgical site infections. The emergence of VRE has further complicated the management of these infections in pediatric populations.
Pathogenesis of Enterococcus Infections
The pathogenesis of enterococcal infections in children involves several key factors:
- Intrinsic Antibiotic Resistance:
- Enterococci possess intrinsic resistance to many commonly used antibiotics.
- This allows them to survive and proliferate in the presence of antibiotic pressure.
- Virulence Factors:
- Enterococcal surface protein (Esp) enhances biofilm formation and colonization.
- Aggregation substance (AS) promotes adherence to host tissues and bacterial aggregation.
- Gelatinase and cytolysin contribute to tissue damage and invasion.
- Biofilm Formation:
- Ability to form biofilms on medical devices and host tissues.
- Biofilms protect bacteria from host immune responses and antibiotics.
- Acquired Antibiotic Resistance:
- Enterococci can acquire resistance genes through horizontal gene transfer.
- VRE strains pose significant treatment challenges.
- Host Factors:
- Immunocompromised state in many pediatric patients increases susceptibility.
- Disruption of normal gut flora by antibiotics allows for enterococcal overgrowth.
In pediatric patients, particularly neonates and immunocompromised children, these pathogenic mechanisms of enterococci, combined with host vulnerability, can lead to significant infections. The ability of enterococci to survive in hospital environments further contributes to their role in nosocomial infections.
Clinical Manifestations of Enterococcus Infections in Children
Enterococcal infections in children can manifest in various ways, depending on the site of infection and the patient's underlying health status. Common clinical presentations include:
- Urinary Tract Infections (UTIs):
- Most common type of enterococcal infection in children
- Symptoms may include fever, dysuria, frequency, and abdominal pain
- Often associated with urinary tract abnormalities or catheterization
- Bloodstream Infections:
- Often associated with central venous catheters or other indwelling devices
- May present with fever, chills, and signs of sepsis
- In neonates, presentations can be subtle and include temperature instability or feeding intolerance
- Endocarditis:
- More common in children with congenital heart defects or prosthetic heart valves
- Symptoms may include persistent fever, new or changing heart murmur, and embolic phenomena
- Intra-abdominal and Pelvic Infections:
- Can occur following abdominal surgery or in association with intra-abdominal abscesses
- Symptoms may include abdominal pain, fever, and signs of peritonitis
- Central Nervous System Infections:
- Rare but can occur, especially in children with neurosurgical devices
- May present with fever, headache, altered mental status, or signs of increased intracranial pressure
- Neonatal Infections:
- Can cause early-onset or late-onset sepsis in newborns
- Presentations may be nonspecific and include respiratory distress, poor feeding, or temperature instability
It's important to note that in many cases, especially in neonates and young infants, the signs and symptoms of enterococcal infections can be nonspecific and may mimic other conditions. This underscores the importance of maintaining a high index of suspicion in at-risk pediatric populations, particularly those with recent antibiotic exposure or prolonged hospitalization.
Diagnosis of Enterococcus Infections in Children
Diagnosing enterococcal infections in children requires a combination of clinical assessment and laboratory investigations. The diagnostic approach includes:
- Clinical Evaluation:
- Thorough history and physical examination
- Assessment of risk factors (e.g., recent antibiotic use, presence of indwelling devices)
- Microbiological Studies:
- Blood cultures: At least two sets from separate sites are recommended
- Urine culture for suspected UTIs
- Culture of other relevant specimens (e.g., cerebrospinal fluid, wound swabs)
- Antimicrobial susceptibility testing, including screening for vancomycin resistance
- Laboratory Tests:
- Complete blood count with differential
- C-reactive protein (CRP) and procalcitonin levels
- Renal and liver function tests
- Imaging Studies:
- Echocardiography in cases of suspected endocarditis
- Ultrasound or CT scans for suspected intra-abdominal infections
- Renal ultrasound in cases of recurrent UTIs
- Molecular Methods:
- PCR-based techniques for rapid identification of enterococcal species
- Detection of specific resistance genes (e.g., vanA, vanB for vancomycin resistance)
Interpretation of results requires careful consideration of the clinical context. For blood cultures, the number of positive cultures and the quantity of growth can help distinguish true infections from contamination. In urinary tract infections, the presence of pyuria along with a significant colony count of enterococci is suggestive of true infection rather than colonization.
The emergence of rapid diagnostic techniques, including matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), has improved the speed and accuracy of enterococcal identification and resistance detection. This can lead to more timely and appropriate antibiotic therapy, which is crucial in managing these infections in children.
Treatment of Enterococcus Infections in Children
Treatment of enterococcal infections in children requires a tailored approach based on the site of infection, severity of illness, and antimicrobial susceptibility patterns. Key aspects of management include:
- Antimicrobial Therapy:
- For non-VRE infections:
- Ampicillin or penicillin is often the first choice for susceptible strains
- Vancomycin for penicillin-resistant strains
- For VRE infections:
- Linezolid is often used, especially in children
- Daptomycin may be considered for bloodstream infections
- Duration of therapy depends on the site and severity of infection, typically ranging from 7-14 days for uncomplicated UTIs to 4-6 weeks for endocarditis
- For non-VRE infections:
- Management of Indwelling Devices:
- Removal of infected central venous catheters or other devices is often necessary for successful treatment
- In some cases, antibiotic lock therapy may be attempted to salvage long-term central lines
- Supportive Care:
- Fluid management and hemodynamic support in cases of sepsis
- Nutritional support, especially in neonates and critically ill children
- Monitoring Response to Treatment:
- Serial blood cultures to document clearance of bacteremia
- Tracking of inflammatory markers (e.g., CRP) to assess response
- Close clinical monitoring for improvement or development of complications
- Management of Complications:
- Surgical intervention may be required for endocarditis, intra-abdominal abscesses, or other deep-seated infections
- Collaboration with relevant subspecialists (e.g., infectious disease, cardiology, urology) as needed
Antibiotic stewardship is crucial in the management of enterococcal infections to prevent further development of antimicrobial resistance. This includes appropriate dosing, duration of therapy, and de-escalation of antibiotics when possible based on culture results.
In neonates and young infants, particular attention must be paid to the dosing and monitoring of antibiotics due to their unique pharmacokinetics and the potential for toxicity. Additionally, the use of combination therapy (e.g., ampicillin plus gentamicin) may be considered for severe infections or endocarditis to achieve synergistic bactericidal activity.
Prevention of Enterococcus Infections in Children
Preventing enterococcal infections in pediatric populations, especially in healthcare settings, is crucial. Key preventive strategies include:
- Hand Hygiene:
- Strict adherence to hand hygiene protocols by healthcare workers, patients, and visitors
- Use of alcohol-based hand rubs or proper handwashing techniques
- Contact Precautions:
- Implementation of contact precautions for patients colonized or infected with VRE
- Use of gowns and gloves when caring for these patients
- Antibiotic Stewardship:
- Judicious use of antibiotics to prevent selection of resistant strains
- Implementation of antibiotic stewardship programs in healthcare facilities
- Limiting the use of broad-spectrum antibiotics when possible
- Device Management:
- Proper insertion and maintenance of central lines and urinary catheters
- Prompt removal of unnecessary indwelling devices
- Environmental Cleaning:
- Regular and thorough cleaning of patient care areas
- Proper disinfection of shared equipment
- Screening and Surveillance:
- Active surveillance for VRE in high-risk units (e.g., NICUs, oncology units)
- Prompt isolation of VRE-positive patients
- Staff Education and Training:
- Ongoing education on infection prevention practices
- Regular audits and feedback on compliance with prevention protocols
- Patient Cohorting:
- Grouping patients with VRE in designated areas when possible
- Assigning dedicated staff to care for VRE-positive patients
In neonatal units, additional measures may include:
- Promoting early enteral feeding with breast milk when possible
- Minimizing the duration of parenteral nutrition
- Implementing skin care protocols to maintain skin integrity
Implementing these preventive strategies requires a multidisciplinary approach involving healthcare providers, infection control specialists, and hospital administration. Regular review and updating of prevention protocols based on local epidemiology and emerging evidence are essential for maintaining their effectiveness.
Furthermore, educating patients and families about the importance of hand hygiene and proper antibiotic use can help extend prevention efforts beyond the healthcare setting. This is particularly important for children with chronic medical conditions who may have frequent healthcare encounters.
Enterococcus Infections in Children
- What are the two most common species of Enterococcus causing infections in humans?
Enterococcus faecalis and Enterococcus faecium - Where are Enterococci normally found in the human body?
Gastrointestinal tract - What is the most common type of Enterococcal infection in children?
Urinary tract infection (UTI) - Which risk factor predisposes children to Enterococcal infections?
Prolonged hospitalization - What is the most common source of Enterococcal bacteremia in hospitalized children?
Intravascular catheters - Which antibiotic combination is commonly used to treat serious Enterococcal infections?
Ampicillin plus gentamicin - What is the term for Enterococcus resistant to vancomycin?
Vancomycin-resistant Enterococcus (VRE) - Which antibiotic is often used to treat VRE infections?
Linezolid - What is the most common clinical presentation of Enterococcal endocarditis in children?
Subacute bacterial endocarditis - Which underlying condition predisposes children to Enterococcal endocarditis?
Congenital heart disease - What is the recommended duration of antibiotic treatment for Enterococcal endocarditis?
4-6 weeks - Which laboratory test is used to detect Enterococcus in clinical specimens?
Culture on blood agar or selective media - What is the Gram stain appearance of Enterococcus?
Gram-positive cocci in pairs or short chains - Which biochemical test is used to differentiate Enterococcus from other streptococci?
Bile esculin test - What is the significance of high-level aminoglycoside resistance in Enterococcus?
Loss of synergistic effect when combined with cell wall-active agents - Which type of hemolysis is typically seen with Enterococcus on blood agar?
Alpha-hemolysis or gamma-hemolysis - What is the role of biofilm formation in Enterococcal infections?
It contributes to antibiotic resistance and persistence of infection - Which Enterococcal surface protein is associated with increased virulence?
Esp (Enterococcal surface protein) - What is the significance of the vanA gene in Enterococcus?
It confers high-level vancomycin resistance - Which infection control measure is crucial in preventing the spread of VRE in hospitals?
Contact precautions - What is the role of probiotic therapy in preventing Enterococcal infections?
It may help restore normal gut flora and prevent colonization - Which neonatal infection is sometimes caused by Enterococcus?
Neonatal sepsis - What is the recommended empiric antibiotic for suspected Enterococcal UTI in children?
Ampicillin - Which imaging study is often performed in children with recurrent Enterococcal UTIs?
Voiding cystourethrogram (VCUG) - What is the significance of Enterococcus in polymicrobial intra-abdominal infections?
It can contribute to antibiotic resistance and treatment failure - Which surgical site infections are commonly associated with Enterococcus in children?
Abdominal and cardiac surgeries - What is the recommended duration of antibiotic treatment for uncomplicated Enterococcal UTI?
7-14 days - Which molecular typing method is used for epidemiological investigations of Enterococcal outbreaks?
Pulsed-field gel electrophoresis (PFGE) - What is the role of echocardiography in managing Enterococcal bacteremia in children?
To detect endocarditis
