Susceptibility of Eikenella corrodens to newer and older quinolones

Abstract

The susceptibilities of 44 clinical strains and a reference strain (ATCC 23834) of EikeneUa corrodens were determined by agar dilution. All isolates were very susceptible (MICs, <2 ,ug/ml) to amifloxacin, ciprofloxacin, difloxacin, enoxacin, norfloxacin, ofloxacin, and Win 35439. Eikenella corrodens is a fastidious gram-negative rod that has been implicated as a pathogen in a variety of infections including abscesses, dental infections, sinusitis, osteomyelitis, lower respiratory tract infections, and endocarditis (1-4, 6, 8, 10, 11). Multiple prior studies have reported that all clinical strains of E. corrodens were susceptible to penicillin G (1, 5, 9). Recently, Trallero et al. (12) reported the isolation of beta-lactamase-producing E. corrodens from intraabdominal abscesses in a 10-year-old boy. Consequently, they recommended that clinical laboratories should now "initiate susceptibility studies of these organisms." E. corrodens is resistant to clindamycin, penicillinase-resistant penicillins, and currently available oral cephalosporins (1, 5). There is, therefore, a need for an oral antimicrobial agent that is consistently active against E. corrodens.The new quinolones are a group of oral agents that have a broad spectrum of activity (13). They are currently undergoing clinical trials in a variety of situations in which E. corrodens is a potential pathogen (7). We therefore studied the in vitro activity of penicillin, vancomycin, and new and old quinolones against members of our stock strain collection, as well as against 20 recently isolated strains of E. corrodens.All 44 strains tested were clinical isolates and were identified by standard criteria (1). ries, Carson, Calif.) supplemented with 5 ,ug of hemin per ml and 0.25% Fildes enrichment (Difco Laboratories, Detroit, Mich.) and incubated overnight in 5 to 10% CO2. The turbidity of growth was adjusted to one-half of a McFarland standard no. 1. Mueller-Hinton agar plates were supplemented with 5% sheep blood and quinolone concentrations from 16 to 0.004 ,ug/ml. Penicillin G concentrations ranged from 0.3 to 40 ,ug/ml, and vancomycin concentrations ranged from 0.25 to 64 ,ug/ml. The plates were inoculated with a Steers replicator (Craft Machine Inc., Chester, Pa.). Antimicrobial solutions were freshly prepared for each test according to the instructions of the manufacturers. Control plates without antimicrobial agents were inoculated before and after each series of antimicrobial agent-containing plates was inoculated. All plates were incubated in 5 to 10% CO2 for 48 h and then examined. Control strains (E. corrodens ATCC 23834, Staphylococcus aureus ATCC 25923 and Escherichia coli ATCC 25922) were tested simultaneously on each run.

Clinical Features of Patients with Invasive Eikenella corrodens Infections and Microbiological Characteristics of the Causative Isolates

“…This bacterium was also reported to be resistant to antistaphylococcal penicillins, aminoglycosides, vancomycin, and erythromycin [22,23]. Penicillin, ampicillin, quinolones, and second-and third-generation cephalosporins are reported to be active against Eikenella corrodens, with tetracycline considered a potential alternative [22][23][24][25]. Susceptibility to first-and second-generation cephalosporins varies [6,25].…”

Intrapocket Chemotherapy in Adult Periodontitis Using a New Controlled‐Release Insert Containing Ofloxacin (PT‐01)

“…OFLX has been proven to have strong bactericidal effects against periodontopathic bacteria in vitro. 32,33 Topical OFLX was effective in experimental Periodontitis in hamsters infected with Actinomyces viscosas34 and in rats ligatured with silk and subsequently infected with Eikenella corrodens.35…”

In Vitro Activities of a New Des-Fluoroquinolone, BMS 284756, and Seven Other Antimicrobial Agents against 151 Isolates of Eikenella corrodens

“…Eikenella corrodens has a somewhat peculiar antimicrobial susceptibility pattern, being susceptible to penicillin but resistant to penicillinase-resistant penicillins such as dicloxacillin, erythromycin, other macrolides, clindamycin, metronidazole, and aminoglycosides (8,9). The fluoroquinolones have been previously shown to be active against E. corrodens (10), but most have limited activity against anaerobic bacteria which are frequent copathogens in oral flora-based infections.…”

“…corrodens has a unique antibiotic susceptibility profile (3,(8)(9)(10) as it is usually susceptible to beta-lactam antibiotics, such as penicillin and ampicillin, but is resistant to penicillinaseresistant penicillins, such as dicloxacillin. Penicillin-resistant strains of E. corrodens have been increasingly isolated from human clinical specimens (23,24).…”

“…Negative reactions were observed for catalase, urease, lysine decarboxylase, arginine dihydrolase, esculin hydrolysis, indole production, and acidification of carbohydrates. Susceptibility testing was performed as previously reported (8,9). Brucella agar supplemented with hemin, vitamin K1, and laked sheep blood was the basal medium.…”