Comparative activities of cefuroxime, amoxicillin-clavulanic acid, ciprofloxacin, enoxacin, and ofloxacin against aerobic and anaerobic bacteria isolated from bite wounds

Abstract

We studied the comparative in vitro activities of 10 oral antimicrobial agents against 147 aerobic and 61 anaerobic bacteria making up species in 13 genera (Staphylococcus aureus, streptococci, Eikenella corrodens, Pasteurella multocida, Haemophilus-Actinobacillus spp., M-5, EF-4, Moraxella spp., Flavobacterium Ilb, Bacteroides melaninogenicus, Bacteroides spp., Fusobacterium spp., and Peptostreptococcus spp.) that were isolated from bite wounds. Cefuroxime was generally >fourfold more active than cephalexin and cefadroxil against all aerobic isolates, including Pasteurella multocida. The fluoroquinolones were highly active against most aerobic isolates but were less active against anaerobic isolates. Ciprofloxacin was generally more active than either enoxacin or ofloxacin. Discrepancies of >30% in the interpretation of susceptibilities between break points suggested by the National Committee for Clinical Laboratory Standards and those related to oral dose peak levels (one-half to one-quarter of maximum achievable concentrations) were noted in 14% (18 of 130) of the instances.The choice of an appropriate antimicrobial regimen for infections caused by animal and human bites poses a dilemma for clinicians. Approximately 80% of bite wounds harbor potential pathogens, including many unusual and fastidious aerobic and anaerobic bacteria (10). Anaerobic bacteria can be isolated from approximately 30 and 60% of animal and human bite wounds, respectively (2, 6, 7, 10), and their isolation has been associated with more severe clinical infections (11). Yet, in an era of cost-consciousness, these wounds are often not cultured aerobically and are rarely cultured anaerobically except in research studies. To compound these problems, most clinical laboratories are unable to determine the in vitro susceptibilities of fastidious aerobic and anaerobic bacteria that are frequently isolated from bite wounds.Consequently, clinicians must sometimes rely on the medical literature to guide therapeutic choices, both empiric and specific. Only two systematic susceptibility studies with large numbers and varieties of bite pathogens exist in the English language literature (2, 9). In these studies both a high percentage of 3-lactamase-producing bacteria (2) and the emergence of bacteria that are resistant to commonly used antimicrobial agents have been noted in several genera of isolates obtained from bite wounds (9). Information about newer alternative therapeutic agents and their in vitro activities against the full spectrum of species isolated from bite wounds is therefore needed to help guide clinicians.Cefuroxime axetil, the new orally administered, esterified formulation of cefuroxime, and ciprofloxacin, an oral fluoroquinolone antibacterial agent, have recently been approved for use in skin and soft tissue infections. Ofloxacin and enoxacin are two other oral fluoroquinolones under investigation that have potential use in skin and soft tissue infections. Since these agents can be used to treat animal and human bite wound infections...

Neisseria weaveri sp. nov. (formerly CDC Group M-5), from Dog Bite Wounds of Humans

“…Although it may be that the patient had a pet dog from which the isolate was acquired, it is also possible that group M-5 strains can be carried in the human oral cavity. Like several other organisms associated with dog bite wounds, group M-5 strains are susceptible to erythromycin, penicillin, and tetracycline (5,11). The organism appears to be widely distributed geographically as our study (Table 1) Characteristics which differentiate N. weaveri from phylogenetically closely related taxa and from phenotypically similar taxa are shown in Table 3.…”

Comparative susceptibilities of 173 aerobic and anaerobic bite wound isolates to sparfloxacin, temafloxacin, clarithromycin, and older agents

“…They have been noted to be active against the aerobic but not many of the anaerobic bacteria isolated from human and animal bite wounds (6,16). Consequently, there is interest in the potential utility of other quinolones.…”

“…Prior studies (3,6,8,9) have noted a high percentage of 3-lactamaseproducing bacteria and the emergence of resistance to commonly used antimicrobial agents in several genera of isolates obtained from bite wounds. Consequently, information about newer alternative therapeutic agents and their in vitro activities against the full spectrum of species isolated from bite wounds is needed to help guide therapeutic choices.The use of fluoroquinolones, such as ciprofloxacin and ofloxacin (6,16), for treating bite wound infections has been considered. They have been noted to be active against the aerobic but not many of the anaerobic bacteria isolated from human and animal bite wounds (6, 16).…”

“…Prior studies (3,6,8,9) have noted a high percentage of 3-lactamaseproducing bacteria and the emergence of resistance to commonly used antimicrobial agents in several genera of isolates obtained from bite wounds. Consequently, information about newer alternative therapeutic agents and their in vitro activities against the full spectrum of species isolated from bite wounds is needed to help guide therapeutic choices.…”

“…The use of fluoroquinolones, such as ciprofloxacin and ofloxacin (6,16), for treating bite wound infections has been considered. They have been noted to be active against the aerobic but not many of the anaerobic bacteria isolated from human and animal bite wounds (6,16).…”