Quinolones and osteomyelitis: state-of-the-art

Exploring theories for the exponential 16-year rise in incidence of necrotising otitis externa in England

Background

Necrotising otitis externa is a severe, life-threatening infection. Epidemiological data demonstrate a dramatic rise in reported cases in England from 2002 to 2017. The reasons for this remain elusive.

Methods

A quantitative descriptive study was undertaken using epidemiological data from the Hospital Episode Statistics database. Cases from 2002 to 2017 were compiled and analysed. Four potential theories were explored to explain the rise in incidence.

Results

Within the 16-year period, 7327 necrotising otitis externa cases were reported. Annual necrotising otitis externa incidence increased 1142 per cent within the 16-year period, from 123 recorded cases in 2002 to 1405 cases in 2017. This correlates with an increasing prevalence of diabetes, an ageing population and likely increased physician awareness of necrotising otitis externa. There is insufficient evidence to support antibiotic resistance as a significant associated factor.

Conclusion

Correlation does not imply causation. It is likely that a combination of factors is contributing to the rise in necrotising otitis externa incidence, including increased physician recognition, diagnosis and accurate clinical coding.

A Prospective Randomized Trial to Assess Oral Versus Intravenous Antibiotics for the Treatment of Postoperative Wound Infection After Extremity Fractures (POvIV Study)

Patients surgically treated for infection after extremity fractures are typically discharged with a 6- to 12-week antibiotic regimen. Intravenous (IV) antibiotics are associated with significant cost and potential complications of deep vein thrombosis, line clotting, and sepsis. Many of the pathogens that cause musculoskeletal infection have both oral (PO) and IV antibiotic options with adequate bioavailability and antibacterial effect, yet IV antibiotics remain the standard of care absent evidence that PO options are clinically as efficacious. The POvIV study is a prospective, multicenter, randomized trial to compare PO with IV antibiotic therapy in patients with postoperative wound infections after extremity fractures. Patients between the ages of 18 and 84 who have a culture-positive surgical site infection after internal fixation for fracture repair or arthrodesis are approached for this study, and if they provide consent, are randomly assigned to receive either PO or IV antibiotics. Antibiotic selection is based on culture and sensitivity results. Randomization determines the route of administration. Patients are followed for 1 year after study enrollment. This study will be the largest prospective randomized trial to evaluate the safety and effectiveness of PO antibiotic use for treatment of postoperative wound infections. Results will inform clinician decisions on antibiotic delivery in patients with postoperative wound infections.

Diabetic foot ulcers: evaluation and management

Diabetic foot ulcers (DFUs) are a common complication of diabetes and present a significant health risk to patients, as well as impose a large economic burden. Evaluation for contributory factors that may impact general health or healing, such as hyperglycemia, peripheral artery disease, neuropathy, and nutritional status, is of the utmost importance. Management of DFUs requires involvement of a multidisciplinary team and a standardized approach to patient care. Standard therapy for DFUs includes offloading and debridement. Assessment and control of infection are critical, including determining the severity of the infection, which may drive therapeutic approaches. For recalcitrant ulcers, adjuvant therapies are used to hasten the healing process, and newer therapies are under investigation.

The management gram-negative bacterial haematogenous vertebral osteomyelitis: a case series of diagnosis, treatment and therapeutic outcomes

PURPOSE

The incidence of gram-negative bacterial haematogenous vertebral osteomyelitis (GNB HVO) is increasing. We performed a retrospective cohort study of patients with this type of infection in an effort to gain an improved understanding of the current clinical presentation, management and outcome.

METHODS

Between May 2007 and May 2010, all patients, over the age of 18 years, suffering from GNB HVO were identified and their microbiological diagnoses were evaluated.

RESULTS

This study identified seventy-nine patients with haematogenous vertebral osteomyelitis (HVO). Of these seventy-nine patients, 10 patients (12.66%) had Gram-negative organisms isolated. These organisms included Escherichia coli (4), Pseudomonas aeruginosa (3), Klebsiella pneumonia (1), Haemophilus influenza (1) and Enterobacter cloacae (1). Eight patients were successfully treated with antibiotics and/or surgery. Of the eight patients whose HVO was cured, five had Ciprofloxacin as part of their definitive antibiotic regime.

CONCLUSION

The treatment of GNB HVO is often challenging because of unpredictable resistance patterns and limited published data on effective treatment regimens. Our study has highlighted the need for prompt microbiological sampling and initiation of early appropriate antibiotic regime. The most effective treatment for GNB HVO was with oral Ciprofloxacin over a period of 6-8 weeks.

Molecular characterization of α-amylase from Staphylococcus aureus

Staphylococcus aureus is one of the prominent Gram positive human pathogen secretes many surface and secretary proteins including various enzymes and pathogenic factors that favour the successful colonization and infection of host tissue. α-amylase is one of the enzymes secreted by S. aureus which catalyses the breakdown of complex sugars to monosaccharides, which are required for colonization and survival of this pathogen in any anatomical locales. In the present study we have cloned, sequenced, expressed and characterized α-amylase gene from S. aureus ATCC12600. The recombinant enzyme has a molecular weight of 58kDa and the kinetics showed Vmax 0.0208±0.033 (mg/ml)/mg/min and Km 10.633±0.737mg/ml. The multiple sequence analysis showed α- amylase of S. aureus exhibited large differences with Bacillus subtilis and Streptococcus bovis. As the crystal structure of S. aureus α- amylase was unavailable, we used homology modelling method to build the structure. The built structure was validated by Ramachandran plot which showed 90% of the residues in the allowed region while no residue was found in the disallowed region and the built structure was close to the crystal structure with Z-Score: -6.85. The structural superimposition studies with α- amylases of Bacillus subtilis and Streptococcus bovis showed distinct differences with RMSD values of 18.158Åand 7.091Å respectively which correlated with enzyme kinetics, indicating α-amylase is different among these bacteria.

Management of malignant (necrotising) otitis externa

Although malignant (necrotising) otitis externa is not a common diagnosis, there have been a number of recently reported cases with pathogens other than Pseudomonas aeruginosa as the causative organism. In addition, there are many published reports of resistance to antibiotics in cases of malignant otitis externa caused by Pseudomonas aeruginosa. This review aims to assess the cases reported and to clarify the current opinion on the diagnostic criteria and management of such cases.

Treatment recommendations and strategies for the management of bone and joint infections

Bone and joint infections are a cause of rising concern, mainly owing to the increasing number of traumatic accidents, the appearance of new groups of patients at risk, the widespread use of prosthetic devices and the emergence of new patterns of antimicrobial resistance. Treatment guidelines and particular strategies for the management of such infections are reviewed. Decisions regarding the best therapeutic modality can be challenging and take into account the factors involved in infection staging, along with a better knowledge of the bacterial biofilm status. Surgery and antibiotic therapy are the keystones of the management, but overall the timing and length of treatment and follow-up should be posed to obtain the best quality of life for the patient. These infections are characteristically intriguing and sometimes need multiple surgical interventions and several courses of therapy. A multi-disciplinary approach is worthwhile in each institution. The collaboration of a specialized team composed by surgeons, pathologists, microbiologists and clinicians will permit diagnostic and therapeutic protocol-guided decisions.

Influência da ciprofloxacina na consolidação óssea de fraturas de fêmur em ratos

OBJETIVO: Apresentar um estudo experimental sobre o efeito da ciprofloxacina na resistência do calo ósseo de fraturas padronizadas de fêmures de ratos. MÉTODOS: Os ratos foram separados em dois grupos de oito animais: o grupo estudo (cipro) e o grupo controle. Os animais foram submetidos à fixação dos fêmures esquerdos com fio metálico intramedular e à confecção de fraturas padronizadas no mesmo osso. O grupo estudo recebeu ciprofloxacina e o grupo controle soro fisiológico durante seis semanas. Após este período, realizou-se estudo radiográfico controle e ensaio biomecânico de três pontos para obtenção da força de flexão mensurada em Newtons. RESULTADOS: As radiografias e a análise macroscópica demonstraram consolidação óssea em todas as fraturas. Foram comparados os resultados encontrados no estudo biomecânico entre os dois grupos, sendo que o grupo cipro apresentou resistência à força de flexão média 71,11 e o grupo controle, força de flexão média 74,78, não apresentando significância estatística (p = 0,601, test t). CONCLUSÃO: Não houve diferença estatística significante na resistência do calo ósseo de fraturas padronizadas de fêmur de ratos após o uso de ciprofloxacina em relação ao grupo controle.

Oral step-down therapy is comparable to intravenous therapy for Staphylococcus aureus osteomyelitis

BACKGROUND

We hypothesized that regimens with an early switch to oral antibiotics are as effective as prolonged parenteral regimens for staphylococcal osteomyelitis.

METHODS

We retrospectively reviewed records of adult patients with osteomyelitis caused by Staphylococcus aureus as determined by sterile site cultures, who had at least 6 months of follow-up post-therapy. The population was divided into two treatment groups: (1) an intravenous group (i.v.) that received > or = 4 weeks of parenteral therapy, and (2) a switch group that received < 4 weeks of intravenous followed by oral therapy.

RESULTS

A total of 72 patients (36 in each group) were identified with groups evenly matched for demographic and clinical characteristics. The overall apparent cure rate was 74%; 69% for the i.v. group and 78% for the switch group (P=0.59). Apparent cure rates were similar regardless of duration of intravenous therapy: 83% < 2 weeks, 72% 2-4 weeks, 75% 4-6 weeks and 66% > or = 6 weeks (P=0.68). Among the 39 patients who received rifampin-based combinations, those treated simultaneously with vancomycin and rifampin did significantly worse than those who received other rifampin combinations (P<0.02). Overall, MRSA infections responded poorly compared to MSSA (65% apparently cured versus 83%). However, 11/14 (79%) MRSA patients who received rifampin combinations, other than vancomycin and rifampin simultaneously, were apparently cured.

CONCLUSIONS

Overall outcomes did not differ significantly between i.v. and switch groups. Given the markedly lower costs and ease of administration, prolonged oral regimens after initial intravenous therapy may be a preferred regimen for staphylococcal osteomyelitis.

Penetration of moxifloxacin into sternal bone of patients undergoing routine cardiopulmonary bypass surgery

This study investigated plasma and bone concentrations of moxifloxacin following a single intravenous dose of 400mg to consider its potential role in the treatment of osteomyelitis. Eight patients who underwent routine cardiopulmonary bypass surgery were enrolled in the study. Plasma and bone samples were collected 2h and 5h after the end of infusion. High performance liquid chromatography was used for the determination of moxifloxacin concentrations. Mean plasma concentrations were 3.36 microg/mL and 2.93 microg/mL at 2h and 5h after the end of infusion. The concentrations in the body and manubrium of the sternal bone were 1.65 microg/g and 1.64 microg/g at 2h and 1.4 microg/g and 1.45 microg/g at 5h, respectively. Moxifloxacin showed good penetration into bone and could be considered for the treatment of osteomyelitis.

Cefotaxime-ciprofloxacin combination therapy for nontyphoid Salmonella bacteremia and paravertebral abscess after failure of monotherapy

Therapeutic failure of monotherapy with either a third-generation cephalosporin or a fluoroquinolone against nontyphoid salmonellae has been observed in clinical practice. Combination therapy with both agents is recommended in the literature for treating life-threatening infections. However, we know of no published case reports that indicate a therapeutic advantage of this combination therapy for nontyphoid salmonellae infections. We describe a 60-year-old man who had breakthrough bacteremia with vertebral osteomyelitis and paravertebral abscess caused by Salmonella enterica serotype Choleraesuis. This was not controlled with sequential monotherapy but was eventually cured with cefotaxime-ciprofloxacin combination therapy. The Etest showed that the strain was susceptible to cefotaxime and ciprofloxacin, but resistant to nalidixic acid. Cefotaxime and ciprofloxacin in combination may be considered as an option for difficult-to-treat salmonellosis.

Adult osteomyelitis

Adult osteomyelitis remains difficult to treat, with considerable morbidity and costs to the health care system. Bacteria reach bone through the bloodstream, from a contiguous focus of infection, from penetrating trauma, or from operative intervention. Bone necrosis begins early, limiting the possibility of eradicating the pathogens, and leading to a chronic condition. Appropriate treatment includes culture-directed antibiotic therapy and operative debridement of all necrotic bone and soft tissue. Treatment often involves a combination of antibiotics. Operative treatment is often staged and includes debridement, dead space management, soft tissue coverage, restoration of blood supply, and stabilization. Clinicians and patients must share a clear understanding of the goals of treatment and the difficulties that may persist after the initial course of therapy or surgical intervention. Chronic pain and recurrence of infection still remain possible even when the acute symptoms of adult osteomyelitis have resolved.

In vitro and in vivo release of ciprofloxacin from osteoconductive bone defect filler

OBJECTIVES

Impregnation of antimicrobial agents within biodegradable carriers with osteoconductive properties could provide the means for one-stage surgical treatment of osteomyelitis. In this study, the in vitro and in vivo antibiotic release from this type of bone defect filler was characterized.

METHODS

Cylindrical pellets (2.5 x 1.5 mm) were manufactured from bioabsorbable poly(L-lactide-co-glycolide) (PLGA) matrix, ciprofloxacin [8.3 +/- 0.1% (w/w)] and osteoconductive bioactive glass microspheres (90-125 microm) [27 +/- 2% (w/w)]. In vitro studies were carried out to delineate the release profile of the antibiotic. The antimicrobial activity of the release antibiotic was verified with MIC testing. In a time-sequence study in the rabbit, pellets were surgically implanted in the proximal tibia and the antibiotic concentrations achieved in bone were measured at 1, 2, 3, 4, 5 and 6 months.

RESULTS

In vitro elution studies showed sustained release of ciprofloxacin at a therapeutic level (>2 microg/mL) over a time period of 4 months. The released ciprofloxacin had maintained its antimicrobial capacity against five standard ATCC strains. In vivo, the delivery system produced high local bone concentrations (247.9 +/- 91.0 mug/g of bone) for a time period of 3 months with no significant systemic exposure. Histomorphometry and micro-CT imaging confirmed new bone formation around the pellets within 3 months as a sign of an independent osteoconductive property of the composite.

CONCLUSIONS

The tested composite seems to be a promising option for local therapy of surgically treated bone infections. The main advantages are the antibiotic release for a definite time period with therapeutic concentrations, which may minimize slow residual release at suboptimal concentrations.

Efficacy of ciprofloxacin-releasing bioabsorbable osteoconductive bone defect filler for treatment of experimental osteomyelitis due to Staphylococcus aureus

The concept of local antibiotic delivery via biodegradable bone defect fillers with multifunctional properties for the treatment of bone infections is highly appealing. Fillers can be used to obliterate surgical dead space and to provide targeted local bactericidal concentrations in tissue for extended periods. Eventually, the osteoconductive component of the filler could guide the healing of the bone defect. The present experimental study was carried out to test this concept in a localized Staphylococcus aureus osteomyelitis model in the rabbit (n = 31). A metaphyseal defect of the tibia was filled with a block of bone cement, followed by insertion of a bacterial inoculum. After removal of the bone cement and surgical debridement at 2 weeks, the defect was filled with a ciprofloxacin-containing (7.6% +/- 0.1%, by weight) composite (treated-infection group) or with a composite without antibiotic (sham-treated group). Both a positive control group (untreated-infection group) and a negative control group were also produced. The treatment response, monitored by positron emission tomography (PET) with fluorine-18-labeled fluorodeoxyglucose ([18F]FDG) at 3 and 6 weeks, showed rapidly decreasing amounts of [18F]FDG uptake in the treated-infection group (P = 0.001 compared with the results for the untreated-infection group at 6 weeks). The bacteriological analysis confirmed the eradication of the bone pathogen in the treated-infection group. However, three animals had culture-positive soft tissue infections. All animals in the sham-treated and untreated-infection groups had culture-positive bone infections with typical radiographic changes of osteomyelitis. Histomorphometry, peripheral quantitative computed tomography, and backscattered electron imaging of scanning electron microscopy images verified the osteoconductive properties of the bioactive glass microspheres within the composite. The median bone ciprofloxacin concentrations were 1.2 and 2.1 microg/g at two anatomic locations of the tibia. This is the first report to show the value of [18F]FDG PET for quantitative monitoring of the treatment response in bone infections. The collaborative results of bacteriologic and [18F-FDG] PET studies showed that use of the multifunctional composite was successful for eradication of the S. aureus pathogen from bone.

Outcomes of osteomyelitis among patients treated with outpatient parenteral antimicrobial therapy

PURPOSE

To examine the effects of diabetes, vascular disease, age, and antimicrobial therapy on clinical outcomes, including amputation rates, in patients with osteomyelitis treated in the outpatient setting.

METHODS

We performed a retrospective chart review of patients treated with intravenous antimicrobial therapy for osteomyelitis at an outpatient infectious diseases practice. All patients were followed for at least 6 months.

RESULTS

Four hundred and fifty-four patients qualified for inclusion, with follow-up information available for up to 10 years. One hundred and thirty-nine patients (31%) had recurrences and 27 (6%) had amputations. Of the recurrences, 108 (78%) occurred within 6 months and 132 (95%) within 1 year. In univariate analyses, peripheral vascular disease, diabetes, and the combination were all associated with the risk of recurrence; age (>70 years) was not. For osteomyelitis due to Staphylococcus aureus, the relative risk of recurrence, using a Cox regression model, was 0.8 for ceftriaxone (95% confidence interval [CI]: 0.4 to 1.5; P = 0.53), 1.1 for cefazolin (95% CI: 0.5 to 2.2; P = 0.80), and 2.5 for vancomycin (95% CI: 1.1 to 5.6; P = 0.04), as compared with the use of a penicillinase-resistant penicillin.

CONCLUSION

Diabetes and peripheral vascular disease are important factors in determining the prognosis of patients with osteomyelitis, but age is not. Almost all recurrences of osteomyelitis occur within 1 year. Recurrence rates with osteomyelitis associated with S. aureus appear to be higher with the use of vancomycin, whereas ceftriaxone and cefazolin appear to be similar to penicillinase-resistant penicillins.

Fluoroquinolones

The fluoroquinolone class of antimicrobial agents has expanded dramatically in the last 5 years and will continue to grow over the next decade. This article discusses the newer fluoroquinolones in detail, including pharmacokinetics, pharmacodynamics, safety, and drug interactions, and the spectrum of in vitro activity. Newer agents are compared and contrasted with the older ones, particularly ciprofloxacin and ofloxacin, and problems with liver toxicity and trovafloxacin are described. Finally, appropriate use of the fluoroquinolones is discussed, including their role in the treatment of urinary tract infections, sexually transmitted diseases, gastrointestinal infections, osteomyelitis, and respiratory tract infections.

Carrier systems for the local delivery of antibiotics in bone infections

Carriers used for the local delivery of antibacterial agents may be classified as nonbiodegradable or biodegradable. A major representative of the former category are the polymethylmethacrylate (PMMA) beads often impregnated with gentamicin which have been commercially available for the last 2 decades. Examples of the latter category include the collagen-gentamicin sponge, apatite-wollastonite glass ceramic blocks, hydroxyapatite blocks, polylactide/polyglycolide implants and the polylactate polymers. All of the above systems release antibiotics at concentrations exceeding those of the minimum inhibitory concentrations (MICs) for the most common pathogens of chronic osteomyelitis without releasing any antibiotic in the systemic circulation and without producing adverse effects. The major disadvantage of the PMMA beads is the need for their surgical removal at the completion of antibiotic release, which usually takes place 4 weeks after their implantation. The biodegradable carriers do not require surgical removal, and of those listed, the collagen-gentamicin sponge has been applied successfully over the last decade for bone infections. Among the other biodegradable systems which are still in experimental stages, polylactate polymers carrying quinolones seem very promising, since they are characterised by prolonged duration of release at concentrations 100 to 1000 times the MICs of the causative bacteria implicated in bone infections; preliminary results have shown these carriers to be very effective in the management of experimental osteomyelitis caused by methicillin-resistant Staphylococcus aureus. Further development of such biodegradable systems will provide a novel approach in the future for the eradication of chronic osteomyelitis.

Comparison of in vitro and in vivo release characteristics of sustained release ofloxacin microspheres

The sustained release nature of ofloxacin microspheres--to eradicate bacterial biofilm associated with chronic infections from sensitive strains of bacteria--was determined both in vitro and in vivo. Ofloxacin microspheres were prepared by emulsion solvent evaporation procedure using poly(glycolic acid-co-dl-lactic acid) (PLGA) as the biodegradable polymer. The microspheres were characterized by scanning electron microscopy, in vitro release in an incubator, and in vivo release in the rat subcutaneous model. The microspheres were highly spherical with a very smooth surface. Approximately 45% of the drug was released from microspheres in sizes of 125-250 microns and 250-425 microns in 2 days compared with approximately 22% from microspheres of size range 37-125 microns indicating that surface area of the microspheres did not control the kinetics of in vitro release. However, about 96% of the drug was released from the three different size ranges in 35 days. The in vitro release profile of microspheres of size range 125-250 microns is not significantly different from microspheres in sizes of 250-425 microns. The peak plasma level of ofloxacin in animals that received the drug suspension occurred within 2 hr and was higher than that of the microspheres that occurred by the end of the second day. The plasma of animals that received the free drug was depleted of ofloxacin by the end of the first day, but the drug was sustained above 0.5 microgram/mL in the plasma of animals that received the microspheres for about 3 weeks. The results suggest that biodegradable ofloxacin microspheres can be prepared that release the antibiotic in vivo for about 3 weeks. This should provide a means for continuous treatment of chronic infections in which bacterial biofilm can occur.

Effect of solvent composition during preparations on the characteristics of enoxacin microparticles

We have studied the effect of the solvent system during preparation on the morphology, encapsulation efficiency, and release characteristics of enoxacin microparticles intended for localized delivery to the bone for the treatment of bone infections. Microparticles of enoxacin were formulated using poly(glycolic acid-co-DL-lactic acid) (PGLA) of different viscosity grades by the solvent-evaporation technique. Microparticles prepared with pure dichloromethane had smoother surfaces and less tendency to aggregate than microparticles prepared with dichloromethane-acetone solvent mixtures, which had porous surfaces. Approximately 65% of the microparticles prepared with pure dichloromethane were < 125 microm in diameter compared with 16% (approx.) of microparticles prepared with dichloromethane-acetone mixtures. Increasing the proportion of acetone from dichloromethane-acetone, 10:0, to dichloromethane-acetone, 1:1, resulted in an increase in encapsulation efficiency from 25 to 37%, and an increase in the yield of microparticles harvested from 39 to 51%. Although a further increase in the amount of acetone to dichloromethane-acetone, 1:9, had no significant effect on the yield, aggregation, or fraction of microparticles below 125 microm in diameter, the encapsulation efficiency increased to 56%. Approximately 55% of enoxacin was released in 24 h for microparticles prepared with dichloromethane-acetone, 1:9, compared with 100% release in 10h and 2h for microparticles of the same size range prepared with dichloromethane-acetone, 1:1, and dichloromethane-acetone, 10:0, respectively. The results suggest that the composition of the dichloromethane-acetone solvent system significantly influences the encapsulation efficiency and the rate of release of enoxacin from microparticles. This is important for the formulation of sustained-release enoxacin microparticles for the localized treatment of osteomyelitis.

Lactic acid polymers as biodegradable carriers of fluoroquinolones: an in vitro study

A biodegradable polymer of DL-dilactide that facilitates release of ciprofloxacin or pefloxacin at levels exceeding MICs for the causative microorganisms of chronic osteomyelitis is described. Duration and peak of release were found to depend on the molecular weight of the polymer. Its characteristics make it promising for treating chronic bone infections.

Adult posttraumatic osteomyelitis of the tibia

Posttraumatic tibial osteomyelitis results from trauma or nosocomial infection from the treatment of trauma that allows organisms to enter bone, proliferate in traumatized tissue, and cause subsequent bone infection. The resulting infection is usually polymicrobial. The patient may be classified using the May and the Cierny-Mader classification systems. The diagnosis is based on the isolation of the pathogen(s) from the bone, or blood cultures. Appropriate therapy of posttraumatic tibial osteomyelitis includes adequate drainage, thorough debridement, obliteration of dead space, stabilization when necessary, wound protection, and specific antimicrobial therapy.

Antimicrobial treatment of chronic osteomyelitis

Chronic osteomyelitis has been a difficult problem for patients and the treating physicians. Appropriate antibiotic therapy is necessary to arrest osteomyelitis along with adequate surgical therapy. Factors involved in choosing the appropriate antibiotic(s) include infection type, infecting organism, sensitivity results, host factors, and antibiotic characteristics. Initially, antibiotics are chosen on the basis of the organisms that are suspected to be causing the infection. Once the infecting organism(s) is isolated and sensitivities are established, the initial antibiotic(s) may be modified. In selecting specific antibiotics for the treatment of osteomyelitis, the type of infection, current hospital sensitivity resistance patterns, and the risk of adverse reactions must be strongly appraised. Antibiotic classes used in the treatment of osteomyelitis include penicillins, beta-lactamase inhibitors, cephalosporins, other beta-lactams (aztreonam and imipenem), vancomycin, clindamycin, rifampin, aminoglycosides, fluoroquinolones, trimethoprim-sulfamethoxazole, metronidazole, and new investigational agents including teicoplanin, quinupristin/dalfopristin, and oxazolidinones. Traditional treatments have used operative procedures followed by 4 to 6 weeks of parenteral antibiotics. Adjunctive therapy for treating chronic osteomyelitis may be achieved by using beads, spacers, or coated implants to deliver local antibiotic therapy and/or by using hyperbaric oxygen therapy (once per day for 90-120 minutes at two to three atmospheres at 100% oxygen).

Outpatient parenteral antimicrobial therapy for osteomyelitis

OPAT for osteomyelitis is effective, safe, and well-established. There are particular considerations with osteomyelitis, however, that relate to patient selection and the plans of therapy. Orthopedic infections may impose physical considerations that need to be considered. Concomitant medical problems, such as diabetes, must be considered and may be good reasons for hospital care aside from the infection. Further investigations of treatment of osteomyelitis are clearly needed, with OPAT patients being good subjects to study.

Clinical applications of quinolones

The quinolone antimicrobials are the class of inhibitors of bacterial topoisomerases that has been developed most fully for clinical use in human medicine. Initial members of the class had their greatest potency against Gram-negative bacteria, but newly developed members have exhibited increased potency against Gram-positive bacteria and soon agents will be available with additional activity against anaerobic bacteria, providing a broad spectrum of potency. After nalidixic acid, the earliest member of the class which was used for treatment of urinary tract infections, the later fluoroquinolone congeners have had sufficient potency, absorption, and distribution into tissue for additional uses in treatment of sexually transmitted diseases, infections of the gastrointestinal tract, respiratory tract, skin, and bones and joints. Tolerability of these agents in usual doses has been good. Acquired bacterial resistance resulting from clinical uses has occurred in particular among staphylococci and Pseudomonas aeruginosa. Intense drug use and ability of resistant pathogens to spread have also contributed to development of resistance in initially more susceptible pathogens such as Escherichia coli and Neisseria gonorrhoeae in certain settings. Preservation of the considerable clinical utility of the quinolone class for the long term will be affected by the extent to which their use is judicious.