Chapter 140. Infections Due to the HACEK Group and Miscellaneous Gram-Negative Bacteria (Part 4) Chryseobacterium Species (Formerly Flavobacterium) C. meningosepticum is an important cause of nosocomial infections, including outbreaks due to contaminated fluids (e.g., disinfectants and aerosolized antibiotics) and sporadic infections due to indwelling devices, feeding tubes, and other fluid-associated apparatuses. Patients with nosocomial C. meningosepticum infection usually have underlying immunosuppression (e.g., related to malignancy). C. meningosepticum has been reported to cause meningitis (primarily in neonates), sepsis, endocarditis, bacteremia, soft tissue infections, and pneumonia. C. indologenes has caused bacteremia, sepsis, and pneumonia, typically in immunocompromised patients with indwelling devices. Chryseobacterium Infections: Treatment Chryseobacteria are often susceptible to fluoroquinolones, TMP-SMX, imipenem, and third- or fourth-generation cephalosporins, but susceptibility testing should be performed. Pasteurella multocida P. multocida is a bipolar-staining, gram-negative coccobacillus that colonizes the respiratory and gastrointestinal tracts of domestic animals; oropharyngeal colonization rates are 70–90% in cats and 50–65% in dogs. P. multocida can be transmitted to humans through bites or scratches, via the respiratory tract from contact with contaminated dust or infectious droplets, or via deposition of the organism on injured skin or mucosal surfaces during licking. Most human infections affect skin and soft tissue; almost two-thirds of these infections are caused by cats. Patients at the extremes of age or with serious underlying disorders (e.g., cirrhosis) are at increased risk for systemic manifestations, including meningitis, peritonitis, osteomyelitis, endocarditis, and septic shock, but cases have also occurred in healthy individuals. If inhaled, P. multocida can cause acute respiratory tract infection, particularly in patients with underlying sinus and pulmonary disease. Pasteurella multocida Infections: Treatment P. multocida is susceptible to penicillin, ampicillin, ampicillin/sulbactam, second- and third-generation cephalosporins, tetracyclines, and fluoroquinolones. β-lactamase-producing strains have been reported. Miscellaneous Organisms Agrobacterium radiobacter (tumefaciens) has usually been associated with infection in the presence of medical devices, including intravascular catheter– related infections, prosthetic-joint and prosthetic-valve infections, and peritonitis caused by dialysis catheters. Most cases occur in immunocompromised hosts, especially individuals with malignancy or HIV infection. Strains are usually susceptible to fluoroquinolones, third-generation cephalosporins, imipenem, TMP- SMX, and aminoglycosides. Chromobacterium violaceum, although rarely a human pathogen, reportedly has been responsible for life-threatening infections with severe sepsis and metastatic abscesses, particularly in children with defective neutrophil function (e.g., those with chronic granulomatous disease). C. violaceum is generally susceptible to ciprofloxacin (500 mg every 12 h PO or 400 mg every 12 h IV), TMP-SMX, and gentamicin. Plesiomonas shigelloides is a freshwater organism that causes acute diarrhea (Chap. 122) and occasionally serious extraintestinal disease, most commonly in immunocompromised hosts. Ochrobactrum anthropi causes infections related to central venous catheters in compromised hosts; other invasive infections have been described. Other organisms include Weeksella species; various CDC groups, such as EF4 and Ve-2; Flavimonas species; Sphingobacterium species; Protomonas species; Oligella urethralis; and Shewanella putrefaciens. The reader is advised to consult subspecialty texts and references for further guidance on these organisms. Further Readings Brouqui P, Raoult D: Endocarditis due to rare and fastidious bacteria. Clin Microbiol Rev 14:177, 2001 [PMID: 11148009] Chometon S et al: Specific real- time polymerase chain reaction places Kingella kingae as the most common cause of osteoarticular infections in young children. Pediatr Infect Dis J 26:377, 2007 Elliott TSJ et al: Guidelines for the antibiotic treatment of endocarditis in adults: Report of the Working Party of the British Society for Antimicrobial Chemotherapy. J Antimicrob Chemother 54:971, 2004 [PMID: 15546974] Goldberg MH, Katz J: Infective endocarditis caused by fastidious oro- pharyngeal HACEK micro- organisms. J Oral Maxillofac Surg 64:969, 2006 [PMID: 16713816] Huang ST et al: Clinical characteristics of invasive Haemophilus aphrophilus infections. J Microbiol Immunol Infect 38:271, 2005 [PMID: 16118675] Jolivet-Gougeon A et al: Antimicrobial treatment of Capnocytophaga infections. Int J Antimicrob Agents 29:367, 2007 Martino R et al: Bacteremia caused by Capnocytophaga species in patients with neutropenia and cancer: Results of a multicenter study. Clin Infect Dis 33:E20, 2001 Paturel L et al: Actinobacillus actinomycetemcomitans endocarditis. Clin Microbiol Infect 10:98, 2004 [PMID: 14759235] Shie SS et al: Characteristics of Achromobacter xylosoxidans bacteremia in northern Taiwan. J Microbiol Immunol Infect 38:277, 2005 [PMID: 16118676] Udaka T et al: Eikenella corrodens in head and neck infections. J Infect 54:343, 2007 Bibliography Darras-Joly C et al: Haemophilus endocarditis: Report of 42 cases in adults and review. Clin Infect Dis 24:1087, 1997 [PMID: 9195062] Das M et al: Infective endocarditis caused by HACEK microorganisms. Annu Rev Med 48:25, 1997 [PMID: 9046942] Holt HM et al: Shewanella algae and Shewanella putrefaciens : Clinical and microbiological characteristics. Clin Microbiol Infect 11:347, 2005 [PMID: 15819859] Janda JM et al: Evolving concepts regarding the genus Aeromonas : An expanding panorama of species, dise ase presentations, and unanswered questions. Clin Infect Dis 27:332, 1998 [PMID: 9709884] Jolivet-Gougeon A et al: In vitro susceptibilities of Capnocytophaga isolates to beta-lactam antibiotics and beta- lactamase inhibitors. Antimicrob Agents Chemother 44:3186, 2000 [PMID: 11036049] Jorgensen JH, Hindler JF: New consensus guidelines from the Clinical and Laboratory Standards Institute for antimicrobial susceptibility testing of infrequently isolated or fastidious bacteria. Ciln Infect Dis 44:280, 2007 Kaiser RM et al: Clinical significance and epidemiology of NO- 1, an unusual bacterium associated with dog and cat bites. Emerg Infect Dis 8:171, 2002 [PMID: 11897069] Kimura R et al: Pasteurella multocida septicemia caused by close contact with a domes tic cat: Case report and literature review. J Infect Chemother 10:250, 2004 [PMID: 15365869] Kugler KC et al: Determination of the antimicrobial activity of 29 clinically important compounds tested against fastidious HACEK group organisms. Diagn Microbiol Infect Dis 34:73, 1999 [PMID: 10342111] Lee CC et al: Fatal case of community- acquired bacteremia and necrotizing fasciitis caused by Chryseobacterium meningosepticum : Case report and review of the literature. J Clin Microbiol 44:1181, 2006 [PMID: 16517926] Molina-Cabrillana J et al: Outbreak of Achromobacter xylosoxidans pseudobacteremia in a neonatal care unit related to contaminated chlorhexidine solution. Eur J Clin Microbiol Infect Dis 26:435, 2007 Paju S et al: Heterogeneity of Actinobacillus actinomycetemcomitans strains in various human infections and relationships between serotype, genotype and antimicrobial susceptibility. J Clin Microbiol 38:79, 2000 [PMID: 10618067] Paul K, Patel SS: Eikenella corrodens infections in children and adolesc ents: Case report and review of the literature. Clin Infect Dis 33:54, 2001 [PMID: 11389495] von Graevenitz A: The role of Aeromonas in diarrhea: A review. Infection 35:59, 2007 Yagupsky P: Kingella kingae: From medical rarity t o an emerging paediatric pathogen. Lancet Infect Dis 4:358, 2004 [PMID: 15172344] . Chapter 140. Infections Due to the HACEK Group and Miscellaneous Gram-Negative Bacteria (Part 4) Chryseobacterium Species (Formerly Flavobacterium). nosocomial infections, including outbreaks due to contaminated fluids (e.g., disinfectants and aerosolized antibiotics) and sporadic infections due to indwelling devices, feeding tubes, and other. medical devices, including intravascular catheter– related infections, prosthetic-joint and prosthetic-valve infections, and peritonitis caused by dialysis catheters. Most cases occur in immunocompromised