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

Antibiotic prophylaxis in pediatric dog bite injuries: Infection rates and prescribing practices

Objective

Pediatric dog bite injuries are a major public health concern and antibiotic prophylaxis is often prescribed due to concern about the development of infection. The Infectious Diseases Society of America recommends 3‒5 days of antibiotic prophylaxis for high-risk dog bites. The purpose of our study was to compare infection rates among patients receiving antibiotic prophylaxis and those who did not receive antibiotic prophylaxis.

Methods

We conducted a retrospective cohort study of children aged 3 months to 17 years enrolled in the healthcare systems' affiliated accountable care organization (ACO). Eligible children with a dog bite injury presented at an urgent care center or emergency department between 2016 and 2019. We excluded children who were immunosuppressed or had bites that required closure by a surgeon. An electronic health record review was completed and ACO claims data were used to determine if a prescription was filled. Patients with an International Classification of Diseases (ICD)-10 code concerning for infection within 7 days of injury were recorded as having a bite infection.

Results

A total of 2653 non-immunosuppressed children presented for care of dog bite injuries and 672 children met eligibility criteria. Thirty-five children developed an infection of their injury. Of the 539 children who received antibiotic prophylaxis, 5.8% developed an infection and 3.0% of the 133 children who did not receive antibiotic prophylaxis developed an infection (p = 0.28).

Conclusion

The overall infection rate for pediatric dog bite injuries was 5.2%. In our single-center study, no difference in infection rates was found between those receiving and not receiving antibiotic prophylaxis.

Simplified Spectrum Score (S3) app for pathogen-agnostic antimicrobial drug spectrum ranking to assess for antimicrobial de-escalation events

Antimicrobial/antibiotic de-escalation (ADE) is a key feature of antimicrobial stewardship programs (ASP) that relies mainly on individual panels for determining ADE events based on subjective ranking of antibiotics' spectrum activity. The lack of consensus among ASP experts leads to reproducibility issues in the measure of this clinical outcome, making difficult to assess its real impact on patient care. The S3 score (Simplified Spectrum Score) app was developed to allow an objective ranking of antibiotics. Ranking was achieved by developing a database harboring pairs of bacteria-antibiotics for which each molecule was assigned a score based on published and clinically validated data from a recognized international committee. S3 score shows a strong correlation relationship and substantial agreement to a clinically validated spectrum score, and its framework enables any person to use it for ADE detection without assuming prior knowledge or training. In addition, its design enables regular updates and sustainability.

Bifidobacterium bifidum Suppresses Gut Inflammation Caused by Repeated Antibiotic Disturbance Without Recovering Gut Microbiome Diversity in Mice

The gut microbiome is a dynamic community that significantly affects host health; it is frequently disturbed by medications such as antibiotics. Recently, probiotics have been proposed as a remedy for antibiotic-induced dysbiosis, but the efficacy of such treatments remains uncertain. Thus, the effect of specific antibiotic-probiotic combinations on the gut microbiome and host health warrants further research. We tested the effect vancomycin, amoxicillin, and ciprofloxacin on mice. Antibiotic administration was followed by one of the following recovery treatments: Bifidobacterium bifidum JCM 1254 as a probiotic (PR); fecal transplant (FT); or natural recovery (NR). Each antibiotic administration and recovery treatment was repeated three times over 9 weeks. We used the Shannon Index and Chao1 Index to determine gut microbiome diversity and assessed recovery by quantifying the magnitude of microbial shift using the Bray-Curtis Index of Dissimilarity. We determined the community composition by sequencing the V3-V4 regions of the 16S ribosomal RNA gene. To assess host health, we measured body weight and cecum weight, as well as mRNA expression of inflammation-related genes by reverse-transcription quantitative PCR. Our results show that community response varied by the type of antibiotic used, with vancomycin having the most significant effects. As a result, the effect of probiotics and fecal transplants also varied by antibiotic type. For vancomycin, the first antibiotic disturbance substantially increased the relative abundance of inflammatory species in the phylum Proteobacteria, such as Proteus, but the effect of subsequent disturbances was less pronounced, suggesting that the gut microbiome is affected by past disturbance events. Furthermore, although gut microbiome diversity did not recover, probiotic supplementation was effective in limiting cecum size enlargement and colonic inflammation caused by vancomycin. However, for amoxicillin and ciprofloxacin, the relative abundances of proinflammatory species were not greatly affected, and consequently, the effect of probiotic supplementation on community structure, cecum weight, and expression of inflammation-related genes was comparatively negligible. These results indicate that probiotic supplementation is effective, but only when antibiotics cause proinflammatory species-induced gut inflammation, suggesting that the necessity of probiotic supplementation is strongly influenced by the type of disturbance introduced to the community.

Clinical Guidelines for the Antibiotic Treatment for Community-Acquired Skin and Soft Tissue Infection

Skin and soft tissue infection (SSTI) is common and important infectious disease. This work represents an update to 2012 Korean guideline for SSTI. The present guideline was developed by the adaptation method. This clinical guideline provides recommendations for the diagnosis and management of SSTI, including impetigo/ecthyma, purulent skin and soft tissue infection, erysipelas and cellulitis, necrotizing fasciitis, pyomyositis, clostridial myonecrosis, and human/animal bite. This guideline targets community-acquired skin and soft tissue infection occurring among adult patients aged 16 years and older. Diabetic foot infection, surgery-related infection, and infections in immunocompromised patients were not included in this guideline.

Practice Guidelines for the Diagnosis and Management of Skin and Soft Tissue Infections: 2014 Update by the Infectious Diseases Society of America

A panel of national experts was convened by the Infectious Diseases Society of America (IDSA) to update the 2005 guidelines for the treatment of skin and soft tissue infections (SSTIs). The panel's recommendations were developed to be concordant with the recently published IDSA guidelines for the treatment of methicillin-resistant Staphylococcus aureus infections. The focus of this guideline is the diagnosis and appropriate treatment of diverse SSTIs ranging from minor superficial infections to life-threatening infections such as necrotizing fasciitis. In addition, because of an increasing number of immunocompromised hosts worldwide, the guideline addresses the wide array of SSTIs that occur in this population. These guidelines emphasize the importance of clinical skills in promptly diagnosing SSTIs, identifying the pathogen, and administering effective treatments in a timely fashion.

Dog and cat bite-associated infections in children

Millions of people throughout the world are bitten by animals each year. About 90 % of the bites are caused by dogs and cats, and infections are the most common complications. As children are the most frequently bitten subjects, pediatricians should provide parents with everything they need to know in order to confront the problem. However, this does not seem to be case and, as the treatment of bite wounds is frequently inappropriate and delayed, the risk of acute infection and sequelae is increased. The main aim of this review is to discuss the epidemiology, microbiology, and clinical characteristics of infections due to dog and cat bites in children, and suggest the best approach to their management. Analysis of the published literature shows that prompt treatment is necessary in order to reduce the risk of infection. The therapeutic measures include wound washing, specific prophylaxis (i.e., tetanus and/or rabies), and antibiotics in the case of immunocompromised patients or deep wounds (particularly if there is evidence of edema or crushing), facial bites, or any wound over a tendon or bone.

Animal bite-associated infections: microbiology and treatment

Human and animal bites may lead to serious infection. The organisms involved tend to originate from the oral cavity of the offending biter, as well as the environment where the injury occurred. A variety of aerobic as well as anaerobic organisms have been isolated from bite wounds, with infection ranging from localized cellulitis to systemic dissemination, leading to severe disease ranging from abscess to bone and joint infection, to endocarditis and brain abscess. Immediate wound management, including recognition of the most commonly associated infectious pathogens, and judicious use of empiric antibiotics are crucial in providing the best care after a bite. Here, we discuss the common animal bite associated infections, and provide the most up to date information regarding their management.

Use of Appropriate Antimicrobials in Wound Management

The primary goal of wound management is to achieve a functional closure with minimal scarring. Preventing infection is important to facilitate the healing process. Most simple, uncomplicated wounds do not need systemic antibiotics but benefit from the use of topical antibiotics. Judicious use of antibiotics reduces unnecessary adverse events and helps reduce the development of resistance. Although antibiotics can help reduce infection risk and promote healing, they are not a substitute for good local wound care, in particular irrigation and surgical débridement. This article reviews the role of antibiotics in emergency department wound management.

Management of human and animal bite wounds: an overview

Serious infections can result from wounds that are caused by bites from animals and humans. Organisms recovered from bite wounds generally originate from the oral cavity of the biting animal, as well as from the patient's skin flora. Anaerobes have been isolated from animal and human bite wound infections, especially those associated with abscess formation. In addition to local wound infections, common complications, such as lymphangitis, septic arthritis, tenosynovitis, and osteomyelitis, and uncommon complications, such as endocarditis, meningitis, brain abscess, and sepsis, may occur. Wound management includes proper local care and, when needed, antimicrobial therapy.

Low risk of infection in selected human bites treated without antibiotics

To assess the need for antibiotics in low-risk human bite wounds, a prospective, double-blind, placebo-controlled study involving 127 patients presenting with low-risk human bite wounds over 2 years to a 40,000 visit per year major academic ED was performed. Low-risk bites penetrated only the epidermis and did not involve hands, feet, skin, overlying joints, or cartilaginous structures. Exclusion criteria included age less than 18 years, puncture wounds, immunocompromise, allergy to penicillin or related compound, or bites greater than 24 hours old. Patients were randomly assigned to receive either a cephalexin/penicillin combination or placebo. One hundred twenty-five patients completed the study. Infection developed in 1 of 62 patients receiving placebo (1.6%, 95% confidence interval CI, 0-7.3%). Infection developed in 0 of 63 patients receiving the cephalexin/penicillin combination (0%, 95% CI, 0-4.6%). Antibiotic treatment of some low-risk human bite wound could be unnecessary. Infection rates appear similar in low-risk human bite wounds whether treated with antibiotics or placebo.

Microbiology and management of human and animal bite wound infections

This article describes the microbiology, diagnosis, and management of human and animal bite wound infections. Various organisms can be recovered from bite wounds that generally result from aerobic and anaerobic microbial flora of the oral cavity of the biting animal, rather than the victim's own skin flora. The role of anaerobes in bite wound infections has been increasingly appreciated. Anaerobes were isolated from more than two thirds of human and animal bite wound infections, especially those associated with abscess formation. This article describes several of the organisms found in the bites of various species. In addition to local wound infection, other complications may occur, including lymphangitis, local abscess, septic arthritis, tenosynovitis, and osteomyelitis. Rare complications include endocarditis, meningitis, brain abscess, and sepsis with disseminated intravascular coagulation, especially in immunocompromised individuals. Wound management includes the administration of proper local care and the use of proper antimicrobial agents when needed.

Management of lacerations in the emergency department

The goals of wound management are simple: avoid infection and achieve a functional and aesthetically pleasing scar. This is achieved by reducing tissue contamination, debriding devitalized tissue, and restoring perfusion in poorly perfused wounds, in conjunction with a well-approximated skin closure.

The Management of Dog Bites

Objective

To review the contemporary management of dog bites with an emphasis on clinical presentation, wound care, microbiology, antimicrobial prophylaxis, and treatment.

Data Sources

The published literature was searched by use of MEDLINE (1990-December 2000) and bibliographic reviews of relevant textbooks and review articles.

Data Selection and Extraction

Review articles, case reports, appropriate meta-analyses, and relevant textbook chapters dealing with mammalian bites and their management were evaluated. All pertinent information was synthesized and incorporated into the present review.

Data Synthesis

The incidence of serious and fatal dog bites has increased because of the acquisition of larger, more aggressive breeds. School-age children and young adults are at the highest risk. Most bites occur on the upper extremities, although head and neck bites are also common. The risk of infection is greatest for crush injuries, puncture wounds, and hand wounds. Infection tends to develop within 24–36 hours of the injury. Complications include osteomyelitis, septic arthritis, tenosynovitis, and septicemia. Most infections are polymicrobial and involve organisms isolated from the skin of the patient and the indigenous oral flora of the dog. Bites should be initially managed under accepted wound care protocols. Wound closure remains controversial and should be reserved for facial and head wounds. Immobilization and elevation are essential for therapeutic success. Prophylactic antibiotics should be reserved for bites at high risk for infection and the immunocompromised host. Whether for prophylaxis or treatment, empiric antimicrobial therapy should be directed against the most common bacteria: Pasteurella spp., streptococci, staphylococci, and anaerobes. Duration and route are dependent on the location and severity of the wound.

Conclusions

Dogs remain the major cause of mammalian bites in the US. It is important for clinicians to have an understanding of the contemporary management of dog bites. Good wound care is central to the prevention and treatment of complications. Appropriate antimicrobial therapy should be directed against both aerobic and anaerobic flora. Careful monitoring is imperative, and antibiotic changes should be made based on clinical response and, if appropriate, the results of culture and sensitivity reports.

Treating mammalian bite wounds

The incidence of dog, cat and human bites has been increasing steadily and represents an important cause of morbidity and mortality in the United States. Approximately half of all Americans will suffer a bite wound during their lifetime, and the annual medical costs of managing these injuries has been estimated to be over $100 million. Possible complications may include disfigurement, dismemberment and infection. Effective management requires rapid medical evaluation and may necessitate surgical intervention and prophylactic antibiotic therapy. As bite wounds are microbiologically diverse and most often polymicrobial in nature, selection of an appropriate antibiotic regimen requires knowledge of common pathogens. Close clinical follow-up is recommended to minimize the risk of late complications.

Newer concepts in antimicrobial therapy

Antimicrobial agents continue to play a significant role in clinical practice not only due to their active role in the treatment of bacterially induced infections. The accompanying anti-inflammatory characteristics and their antagonism against superantigens add to their importance. The practitioner must also be aware of both overt and covert unwanted effects. During the past decade, the new quinolones, advanced macrolides, and better cephalosporins have been introduced. The staid penicillins have been up-graded with the addition of a beta-lactamase inhibitor. Many antibiotics have been available for several decades but new uses for them and their derivatives permit the dermatologist to have a more versatile armamentarium. Rifamycin has been shown to be effective in the treatment of leishmaniasis. The new macrolide, clarithromycin, will reduce the lesions of acne vulgaris and acne rosacea. Although phototoxicity was well recognised in the sulfonomides, several quinolones can create similar light-induced problems. Bullous diseases are known to be instigated by the penicillins, while vasculitis may be caused by a quinolone. Even porphyria has been reported to be induced by a tetracycline. Antimicrobial therapy has been an integral part of dermatologic practice since the introduction of the sulfa drugs six decades ago. Whether skin is affronted by more pathogenic bacteria than any other organ or whether the percentage of infectious etiologies is greater for cutaneous maladies than for other organ afflictions is not germane to this presentation. The facts remain that signs and symptoms of many dermatitides are diminished or even eliminated by antimicrobials [1, 2, 3, 4].

Bacteriologic analysis of infected dog and cat bites. Emergency Medicine Animal Bite Infection Study Group

BACKGROUND AND METHODS

To define better the bacteria responsible for infections of dog and cat bites, we conducted a prospective study at 18 emergency departments. To be eligible for enrollment, patients had to meet one of three major criteria for infection of a bite wound (fever, abscess, and lymphangitis) or four of five minor criteria (wound-associated erythema, tenderness at the wound site, swelling at the site, purulent drainage, and leukocytosis). Wound specimens were cultured for aerobic and anaerobic bacteria at a research microbiology laboratory and, in some cases, at local hospital laboratories.

RESULTS

The infected wounds of 50 patients with dog bites and 57 patients with cat bites yielded a median of 5 bacterial isolates per culture (range, 0 to 16) at the reference laboratory. Significantly more isolates grew at the reference laboratory than at the local laboratories (median, 1; range, 0 to 5; P<0.001). Aerobes and anaerobes were isolated from 56 percent of the wounds, aerobes alone from 36 percent, and anaerobes alone from 1 percent; 7 percent of cultures had no growth. Pasteurella species were the most frequent isolates from both dog bites (50 percent) and cat bites (75 percent). Pasteurella canis was the most common isolate of dog bites, and Past. multocida subspecies multocida and septica were the most common isolates of cat bites. Other common aerobes included streptococci, staphylococci, moraxella, and neisseria. Common anaerobes included fusobacterium, bacteroides, porphyromonas, and prevotella. Isolates not previously identified as human pathogens included Reimerella anatipestifer from two cat bites and Bacteroides tectum, Prevotella heparinolytica, and several porphyromonas species from dog and cat bites. Erysipelothrix rhusiopathiae was isolated from two cat bites. Patients were most often treated with a combination of a beta-lactam antibiotic and a beta-lactamase inhibitor, which, on the basis of the microbiologic findings, was appropriate therapy.

CONCLUSIONS

Infected dog and cat bites have a complex microbiologic mix that usually includes pasteurella species but may also include many other organisms not routinely identified by clinical microbiology laboratories and not previously recognized as bite-wound pathogens.

Activities of HMR 3004 (RU 64004) and HMR 3647 (RU 66647) compared to those of erythromycin, azithromycin, clarithromycin, roxithromycin, and eight other antimicrobial agents against unusual aerobic and anaerobic human and animal bite pathogens isolated from skin and soft tissue infections in humans

The activities of HMR 3004 and HMR 3647 and comparator agents, especially macrolides, were determined by the agar dilution method against 262 aerobic and 120 anaerobic strains isolated from skin and soft tissue infections associated with human and animal bite wounds. HMR 3004 and HMR 3647 were active against almost all aerobic and fastidious facultative isolates (MIC at which 90% of the isolates are inhibited [MIC90], < or = 0.5 and 1 microg/ml, respectively) and against all anaerobes [Bacteroides tectum, Porphyromonas macacae (salivosa), Prevotella heparinolytica, Porphyromonas sp., Prevotella sp., and peptostreptococci] at < or = 0.25 and < or = 0.5 microg/ml, respectively, except Fusobacterium nucleatum (HMR 3004, MIC90 = 16 microg/ml; HMR 3647, MIC90 = 8 microg/ml) and other Fusobacterium species (MIC90, 1 and 2 microg/ml, respectively). In general, HMR 3004 and HMR 3647 were more active than any of the macrolides tested. Azithromycin was more active than clarithromycin against all Pasteurella species, including Pasteurella multocida subsp. multocida, Eikenella corrodens, and Fusobacterium species, while clarithromycin was more active than azithromycin against Corynebacterium species, Weeksella zoohelcum, B. tectum, and P. heparinolytica.

In vitro activity of Bay 12-8039, a new 8-methoxyquinolone, compared to the activities of 11 other oral antimicrobial agents against 390 aerobic and anaerobic bacteria isolated from human and animal bite wound skin and soft tissue infections in humans

The in vitro activity of Bay 12-8039, a new oral 8-methoxyquinolone, was compared to the activities of 11 other oral antimicrobial agents (ciprofloxacin, levofloxacin, ofloxacin, sparfloxacin, azithromycin, clarithromycin, amoxicillin clavulanate, penicillin, cefuroxime, cefpodoxime, and doxycycline) against 250 aerobic and 140 anaerobic bacteria recently isolated from animal and human bite wound infections. Bay 12-8039 was active against all aerobic isolates, both gram-positive and gram-negative isolates, at < or = 1.0 microg/ml (MICs at which 90% of isolates are inhibited [MIC90s < or = 0.25 microg/ml) and was active against most anaerobes at < or = 0.5 microg/ml; the exceptions were Fusobacterium nucleatum and other Fusobacterium species (MIC90s, > or = 4.0 microg/ml) and one strain of Prevotella loeschii (MICs, 2.0 microg/ml). In comparison, the other quinolones tested had similar in vitro activities against the aerobic strains but were less active against the anaerobes, including peptostreptococci, Porphyromonas species, and Prevotella species. The fusobacteria were relatively resistant to all the antimicrobial agents tested except penicillin G (one penicillinase-producing strain of F. nucleatum was found) and amoxicillin clavulanate.

Comparative in vitro activities of DU-6859a, levofloxacin, ofloxacin, sparfloxacin, and ciprofloxacin against 387 aerobic and anaerobic bite wound isolates

The activities of DU-6859a, levofloxacin, ofloxacin, sparfloxacin, and ciprofloxacin against bite wound isolates were determined by the agar dilution method. DU-6859a was the most active compound (MICs, < or = 0.125 microg/ml) against all Pasteurella species, Staphylococcus aureus, and streptococci; anaerobes were susceptible to < or = 0.5 microg/ml, except fusobacteria, which were susceptible to < or = 2 microg/ml. Against aerobes, levofloxacin was more active than ofloxacin (MIC at which 90% of isolates are inhibited [MIC90], < or = 1.0 microg/ml for both) and sparfloxacin and ciprofloxacin were also active (MIC90s, < or = 0.25 and < 1 microg/ml, respectively).

Advances in medical and antibiotic management of infective endocarditis

Infective endocarditis remains a serious medical problem despite advancements in laboratory detection, echocardiographic techniques, and newer antibiotic agents. This article summarizes the microbial agents in infective endocarditis, in addition to developments in medical and antibiotic management.

Dog, cat, and human bites: a review

It is estimated that half of all Americans will be bitten by an animal or another human being during their lifetimes. The vast majority of the estimated 2 million annual mammalian bite wounds are minor, and the victims never seek medical attention. Nonetheless, bite wounds account for approximately 1% of all emergency department visits and more than $30 million in annual health care costs. Infection is the most common bite-associated complication; the relative risk is determined by the species of the inflicting animal, bite location, host factors, and local wound care. Most infections caused by mammalian bites are polymicrobial, with mixed aerobic and anaerobic species. The clinical presentation and appropriate treatment of infected bite wounds vary according to the causative organisms. Human bite wounds have long had a bad reputation for severe infection and frequent complication. However, recent data demonstrate that human bites occurring anywhere other than the hand present no more of a risk for infection than any other type of mammalian bite. The increased incidence of serious infections and complications associated with human bites to the hand warrants their consideration and management in three different categories: occlusional/simple, clenched fist injuries, and occlusional bites to the hand. This article reviews dogs, cat, and human bite wounds, risk factors for complications, evaluation components, bacteriology, antimicrobial susceptibility patterns, and recommended treatments. Epidemiology, clinical presentation, and treatment of infections caused by Pasteurella multocida, Capnocytophaga canimorsus, Eikenella corrodens, and rhabdovirus (rabies only) receive particular emphasis.

Comparative in vitro activities of azithromycin, Bay y 3118, levofloxacin, sparfloxacin, and 11 other oral antimicrobial agents against 194 aerobic and anaerobic bite wound isolates

The activities of sparfloxacin, levofloxacin, Bay y 3118, azithromycin, cefprozil, loracarbef, and nine other oral antimicrobial agents against 194 aerobic and anaerobic clinical bite wound isolates were determined by the agar dilution method. Sparfloxacin, levofloxacin, and Bay y 3118 were active against all aerobic isolates (MICs at which 90% of the isolates are inhibited [MIC90], < or = 1.0 microgram/ml for sparfloxacin and levofloxacin and 0.1 microgram/ml for Bay y 3118) and many anaerobic isolates, with the exception of the fusobacteria. Azithromycin was more active than erythromycin by 1 to 2 dilutions against many aerobes, including Pasteurella multocida and Eikenella corrodens, and by 2 to 4 dilutions against anaerobic isolates. Cefprozil was more active (MIC90, < or = 1 microgram/ml) than loracarbef (MIC90, < or = 4 micrograms/ml) against aerobic gram-positive isolates, but both had poor activity (MIC90, > or = 16 micrograms/ml) against peptostreptococci. Both cefprozil and loracarbef had MIC90s of < or = 0.5 micrograms/ml against P. multocida.

A review of the microbiology of amoxycillin/clavulanic acid over the 15 year period 1978-1993

A review of the published literature over the period 1978-1993 was undertaken to assess any changes in the prevalence of beta-lactamase-producing bacterial pathogens and also any changes in the susceptibility in these pathogens to amoxycillin/clavulanate. The review has involved the examination of over 1500 publications. The review shows that in general there has been an increase in the frequency of beta-lactamase-producing pathogens resistant to ampicillin and amoxycillin but there is no evidence for any significant increase in resistance to amoxycillin/clavulanate over the period of the review.

The management of dog bites and dog bite infections to the hand

Dog bites account for approximately one of 200 emergency room visits. The majority of bites are from dogs known to the victim. Due to the numerous small compartments and the thin covering of soft tissue over the bones and joints, bite wounds to the hand are more likely to become infected that are bites to the arm, leg, or face. Improper management can result in significant morbidity and prolonged treatment. This article discusses the microbiology of dog bite wounds, antibiotic selection, and proper wound management.

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

The in vitro activities of sparfloxacin, temafloxacin, ciprofloxacin, ofloxacin, clarithromycin, erythromycin, tetracycline, cephalothin, penicillin G, and amoxicillin-clavulanic acid against 173 recent clinical bite wound isolates were determined by agar dilution. Sparfloxacin was active against all strains (MIC for 90% of strains tested, < or = 1 micrograms/ml) except for most fusobacteria and one-third of the Prevotella spp. The other fluoroquinolones had similar activities but higher MICs, especially for streptococci. Clarithromycin was more active against many isolates including Pasteurella multocida than erythromycin, with MICs of < or = 2 micrograms/ml (versus 4 micrograms/ml for erythromycin).

Ofloxacin. A reappraisal of its antimicrobial activity, pharmacology and therapeutic use

Ofloxacin is a fluoroquinolone whose primary mechanism of action is inhibition of bacterial DNA gyrase. In vitro it has a broad spectrum of activity against aerobic Gram-negative and Gram-positive bacteria, although it is poorly active against anaerobes. Ofloxacin, unlike most other broad spectrum antibacterial drugs, can be administered orally as well as intravenously. Penetration into body tissues and fluids is highly efficient. Clinical trials with orally and intravenously administered ofloxacin have confirmed its potential for use in a wide range of infections, where it has generally proved as effective as standard treatments. Ofloxacin in well tolerated, and in comparison with other available fluoroquinolones is less likely to cause clinically relevant drug interactions. Ofloxacin thus offers a valuable oral treatment (with an option for intravenous administration if necessary) for use in a wide range of clinical infections, but with a particular advantage in more severe or chronic infections when recourse to parenteral broad spectrum agents would normally be required, thereby providing cost savings and additionally allowing outpatient treatment.

Erythromycin failure with subsequent Pasteurella multocida meningitis and septic arthritis in a cat-bite victim

We report the case of a 75-year-old woman who developed Pasteurella multocida meningitis and septic arthritis while being treated for a cat-bite wound infection with erythromycin. Review of the literature revealed that erythromycin has poor in vitro activity against this bacterium and has been associated with serious clinical failures. We recommend that erythromycin not be prescribed for empiric therapy of established animal-bite infections. Suggestions for optimal empiric therapy of animal-bite infections and the differential diagnosis of severe cat-bite-associated sepsis are discussed.

Management of human and animal bite wounds

Bite wounds, usually by dogs, cats, and human beings, affect one of two Americans during his or her lifetime and 1 to 2 million Americans annually. Despite the relative frequency of bite wounds, there are few prospective studies to define optimal care; consequently, diverse methods are used. In this article I review the incidence, bacteriology, clinical spectrum, complications, and treatment of animal and human bite wounds. The spectrum of pathogenic bacteria that cause bite infections is broader than is generally appreciated and includes both aerobic and anaerobic bacteria. Pasteurella multocida is found in only 20% to 25% of dog bite wounds. In choosing empiric antimicrobial therapy, clinicians must consider the diverse causative bacteria and their characteristic susceptibility patterns. Liberal irrigation and elevation of the injured part are also cornerstones of therapy. Early, aggressive medical and surgical management can minimize, if not prevent, complications.

Fluoroquinolone antimicrobial agents

The fluoroquinolones, a new class of potent orally absorbed antimicrobial agents, are reviewed, considering structure, mechanisms of action and resistance, spectrum, variables affecting activity in vitro, pharmacokinetic properties, clinical efficacy, emergence of resistance, and tolerability. The primary bacterial target is the enzyme deoxyribonucleic acid gyrase. Bacterial resistance occurs by chromosomal mutations altering deoxyribonucleic acid gyrase and decreasing drug permeation. The drugs are bactericidal and potent in vitro against members of the family Enterobacteriaceae, Haemophilus spp., and Neisseria spp., have good activity against Pseudomonas aeruginosa and staphylococci, and (with several exceptions) are less potent against streptococci and have fair to poor activity against anaerobic species. Potency in vitro decreases in the presence of low pH, magnesium ions, or urine but is little affected by different media, increased inoculum, or serum. The effects of the drugs in combination with a beta-lactam or aminoglycoside are often additive, occasionally synergistic, and rarely antagonistic. The agents are orally absorbed, require at most twice-daily dosing, and achieve high concentrations in urine, feces, and kidney and good concentrations in lung, bone, prostate, and other tissues. The drugs are efficacious in treatment of a variety of bacterial infections, including uncomplicated and complicated urinary tract infections, bacterial gastroenteritis, and gonorrhea, and show promise for therapy of prostatitis, respiratory tract infections, osteomyelitis, and cutaneous infections, particularly when caused by aerobic gram-negative bacilli. Fluoroquinolones have also proved to be efficacious for prophylaxis against travelers' diarrhea and infection with gram-negative bacilli in neutropenic patients. The drugs are effective in eliminating carriage of Neisseria meningitidis. Patient tolerability appears acceptable, with gastrointestinal or central nervous system toxicities occurring most commonly, but only rarely necessitating discontinuance of therapy. In 17 of 18 prospective, randomized, double-blind comparisons with another agent or placebo, fluoroquinolones were tolerated as well as or better than the comparison regimen. Bacterial resistance has been uncommonly documented but occurs, most notably with P. aeruginosa and Staphylococcus aureus and occasionally other species for which the therapeutic ratio is less favorable. Fluoroquinolones offer an efficacious, well-tolerated, and cost-effective alternative to parenteral therapies of selected infections.