Chapter 140. Infections Due to the HACEK Group and Miscellaneous Gram-Negative Bacteria (Part 2) ppsx

Chapter 140. Infections Due to the HACEK Group and Miscellaneous Gram-Negative Bacteria (Part 2) Kingella kingae Because of improved microbiologic methodology, isolation of K. kingae is increasingly common. Inoculation of clinical specimens (e.g., synovial fluid) into aerobic blood culture bottles enhances recovery of this organism. In recent series, K. kingae has been the third most common cause of septic arthritis in children <24 months of age; staphylococcal and streptococcal species remain most prevalent. Invasive K. kingae infections with bacteremia are associated with upper respiratory tract infections and stomatitis. Both K. kingae colonization and primary herpes—a major cause of stomatitis—peak in children 6–48 months of age. K. kingae bacteremia can present with a petechial rash similar to that seen in Neisseria meningitidis sepsis. Infective endocarditis, unlike other infections with K. kingae, occurs in older children and adults. The majority of patients have preexisting valvular disease. There is a high incidence of complications, including arterial emboli, cerebrovascular accidents, tricuspid insufficiency, and congestive heart failure with cardiovascular collapse. Endocarditis Caused by HACEK Organisms: Treatment See Table 140-1. Native-valve endocarditis should be treated for 4 weeks with antibiotics, whereas prosthetic-valve endocarditis requires 6 weeks of therapy. The cure rates for HACEK prosthetic-valve endocarditis appear to be high. Unlike prosthetic-valve endocarditis caused by other gram-negative organisms, HACEK endocarditis is often cured with antibiotic treatment alone— i.e., without surgical intervention. Table 140- 1 Treatment of Endocarditis Caused by HACEK Group Organisms a Organism Initial Therapy Alternative Agents Commen ts Haemophilus species, Actinobacillus actinomycetemcomita Ceftriaxo ne (2 g/d) Ampicillin/sulbact am (3 g of ampicillin q6h) or fluoroquinolones b Ampicill in ± an aminoglycoside can be used if ns the organism does not produce β- lactamase. c Cardiobacteriu m hominis Penicillin (16– 18 mU/d in 6 divided doses) or ampicillin (2 g q4h) Ceftriaxone (2 g/d) or ampicillin/sulbactam (3 g of ampicillin q6h) An aminoglycoside (gentamicin, 3 mg/kg per day in 3 divided doses) may be added, but its value has not been proven. The organism is usually pansensitive, but high- level penicillin resistance has been reported. Eikenella corrodens Ampicilli n (2 g q4h) Ceftri axone (2 g/d) or fluoroquinolones b The organism is typically resistant to clindamycin, metronidazole, and aminoglycoside s. Kingella kingae Ceftriaxo ne (2 g/d) or ampicillin (3 g q6h) Fluoroquinolones b The prevalence of β-lactamase- producing strains is increasing. Efficacy for invasive infections is best demonstrated for first- line treatments. a Susceptibility testing should be performed in all cases to guide therapy. b Fluoroquinolones are not recommen ded for treatment of children <17 years of age. c European guidelines for endocarditis recommend the addition of gentamicin (3 mg/kg per day in 3 divided doses for 2–4 weeks). . Chapter 140. Infections Due to the HACEK Group and Miscellaneous Gram-Negative Bacteria (Part 2) Kingella kingae Because of improved microbiologic. prosthetic-valve endocarditis requires 6 weeks of therapy. The cure rates for HACEK prosthetic-valve endocarditis appear to be high. Unlike prosthetic-valve endocarditis caused by other gram-negative. age; staphylococcal and streptococcal species remain most prevalent. Invasive K. kingae infections with bacteremia are associated with upper respiratory tract infections and stomatitis. Both K.