The antibiotic puzzle : Guidelines for the family physician

G Harding, S Field, R MacMahon, T Louie and the Prairie Consensus Conference Group. The a n tibiotic puzzle: Guidelines for the family physician. Can J Infect Dis 1997;8(Suppl C):2C-16C. Choosing the most appropriate antibiotic for the treatment of common infections is becoming increasingly complex. New drugs and new classes of antibiotics are being developed and made available, and emerging resistance and pharmacoeconomics play important roles. The Canadian healthcare system presents a unique challenge for prescribing physicians because pharmacoeconomic conside rations are becoming increasingly important. It is important that Canadian guidelines be developed to address the needs of Canadian physicians. A consensus conference was held in October 1996 to discuss appropria te guidelines for antibiotic recommendations for common adult respiratory, urinary tract a nd diabetic foot infections. In August 1997, the guidelines were reviewed and updated as part of a second meeti ng of the group on antimicrob ial resistance. The final recommendations constitute the information in this document. The panel of physicians and pharmaceutical doctors from the Prairie provi nces of Alberta, Saskatchewan and Man itoba included family physicians and specialists in internal medicine, resp irology, urology, infectious diseases, medical microbiology and pharmacoeconomics.

Le casse-tete de l'antibiotherapie Directives a ('intention du medecin de fa mille RESUME: Le choix de l"antibiotique le plus approprie pour le traitement des affections courantes devient de plus en plus complexe.De nouveaux medicaments et de nouvelles classes d'antibiotiques font constamment leur apparition sur le marche, sans compter que !'emergence des souches resistantes et que la pharmacoeconomie jouent aussi un role preponderant.Le systeme canadien de soins de sante pose un defi unique aux medecins de premier recours a cause de !'importance croissante accordee aux prin cipes de pharmacoeconomie.II est important de mettre au point des directives qui puissent repondre specifiquement aux besoins des medecins canadiens.Une conference consensuelle a eu lieu en octobre 1996; on ya discute des directives relatives a l'antibiotherapie appliquee aux infections respiratoires et urinaires courantes de l"adulte, ainsi qu'aux infections du pied chez le diabetique .En aout 1997, les directives ont ete passees en revue et mises a jour dans le cadre d'une seconde rencontre du groupe forme pour traiter de la resistance aux antimicrobiens.Les recommandations finales forment l'essentiel du present document.Un cornice de medecins et de pharmacologues des provinces de l'Ouest (Alberta, Saskatchewan et Manitoba) ete forme et regroupait des medecins de families , des internistes , des pneumologues, des urologues , des infectiologues, des microbiologistes et des specialistes de la pharmacoeconomie.
C hoosing the most appropriate antibiotic for the treatment of common infections is becoming increasingly complex.New drugs and new classes of antibiotics are being developed and made available, emerging resistance is still a factor and pharmacoeconomics plays a very important role.In addition, at times, standard first-line treatment may not be appropriate, especially when the risk and consequences of treatment failure are particularly high.The plan: With changing resistance profiles, regional microbiological prevalence differences and the availability of new anti-infective agents, therapeutic guidelines must be reviewed regularly and updated .It is important that Canadian guidelines be developed to address the needs of Canadian physicians.The need for practical guidelines for family physicians was identified.
The Canadian healthcare system presents a unique challenge for prescribing physicians because pharmacoeconomic considerations are becoming increasingly important.It is no longer acceptable to look at the cost of a drug alone.Cost analysis should consider indirect costs such as those associated with adverse effects, time lost from work and treatment failure, and intangible costs such as the cost of a life saved.In some instances the higher cost of second-line antibiotics can be justified if treatment is expected to reduce the risk of deterioration, which may result in hospitalization.Thus, where appropriate, pharmacoeconomics should be considered when making therapeutic recommendations.The panel: In October 1996, Dr Godfrey Harding brought together a panel of physicians and pharmaceutical doctors from the Prairie provinces of Alberta, Saskatchewan and Manitoba for a consensus conference to discuss appropriate guidelines for antibiotic recommendations for common adult respiratory, urinary tract and diabetic  foot infections.The panel included family physicians and specialists in internal medicine, respirology, urology, infectious diseases, medical microbiology and pharmacoeconomics.The panel 's mandate was to develop practical, current antibiotic treatment guidelines that would be useful to a family physician in everyday practice.
Team leaders (chairs) were identified before the workshop and included Ors Stephen Field, Ross MacMahon and Thomas Louie.After reviewing the pertinent literature, they developed working documents with references, which were handed out before the plenary sessions .The working documents with proposed recommendations were presented at a plenary session before the entire group for discussion.In addition , Dr George Zhanel gave a talk on pharmacoeconomic issues pertinent to these topic areas.The next day, the team leaders chaired small group breakout sessions on their respective topic areas, and the recommendations were revised.These recommendations were presented to the entire group and agreed upon at a second plenary session.In August 1997, the proposed guidelines were reviewed and updated as part of a second meeting of the group on antimicrobial resistance.The final recommendations, which constitute the information in this document, were agreed upon at the final plenary session

USE OF ANTIBIOTICS IN RESPIRATORY TRACT INFECTIONS
The etiological organisms involved in a respiratory tract infection are usually unknown when therapy is initiated, and an antibiotic must be chosen without the benefit of microbiological diagnosis .It may be difficult to confirm a diagnosis because of previous antibiotic therapy, normal flora or the presence of other contaminating potential pathogens in culture specimens.Antibiotic selection is based on the spectrum of pathogens usually seen in a particular setting.Acute sinusitis: Seventy per cent of bacterial isolates found in adults and children with acute sinusitis are Streptococcus pneumoniae and Hemophilus ifJ!luenz ae (1) .Nasal swab results do not correlate well with antral cultures , and such swabs are not recommended for culture.

Dose and duration
160/800 mg bid for 1 0 days 200 mg fi rst day, then 100 rn g once da ily fo r nine days 250 to 500 mg tid fo r 10 days Decongestants and analgesics are helpful in acute sinusitis , but nasal decongestants should not be given for more than five days to prevent rebound vasodilation.Antihistamines should be avoided because their anticholinergic effect can interfere with normal mucociliary clearance ( 1) .
Although 40% of cases of acute sinusitis resolve spontaneously, a therapeutic advantage to antibiotic therapy was demonstrated in some but not all studies ( 1-4).Tables 1 and 2 reflect the consensus agreement by the panel, with the caveat that local resistance profiles be considered when choosing therapy.Recent microbiological sensitivity surveys have shown a rising prevalence of penicillin-resistant s pneumoniae and beta-lactamase-producing H ifJ!luenz ae, which may be as high as 40% (5) .In view of the steady rise of antibiotic resistance, amoxicillin may not remain a first-line antibiotic choice in the future .Chronic sinusitis: Chronic sinusitis is usually the result of ostial obstruction due to allergy, deviated septum or nasal polyps.Topical steroids and antihistamines may Opportunistic organisms that can grow in obstructed sinuses include the anaerobes H iryluenzae and S aureus.Amoxicillin/clavulanate is effective against most anaerobes.Pseudomonas aeruginosa may be found if polyps are present and may be treated with ciprofloxacin.
Referral to a specialist is recommended for most patients.Surgery may be necessary if medical therapy is unsuccessful.

Recommendation for treatment of chronic sinusitis • Topical steroids and antihistamines • Prolonged antibiotic therapy for bacterial infection • Referral if medical treatment is unsuccessful
Acute exacerbations of chronic bronchitis: Measures to prevent acute exacerbation of chronic bronchitis include smoking cessation, vaccination against influenza and, in selected cases , vaccination against s pneumoniae.Exacerbations can be precipitated by a variety of triggers, both infectious and noninfectious.Patients should be advised to avoid irritants such as cigarette smoke during an exacerbation.Exacerbations should be treated with bronchodilators, corticosteroids, supplemental oxygen if the patient is hypoxemic and antibiotics.
Can J Infect Dis Vol 8 Su ppl C November/ December 1997

Recommendations for treatment of acute exacerbations of chronic bronchitis • Bronchodilators • Corticosteroids • Supplemental oxygen • Antibiotics
Canadian guidelines for the management of chronic bronchitis were published in 1994 (6).These recommendations stratified patients into five groups on the basis of severity of disease, partly defined by the forced expiratory volume in 1 s, number of exacerbations per year and presence of comorbidity.The panel adopted the guidelines mentioned above and agreed with the antibiotic choices detailed there, which were based on the likelihood of bacterial infection in a particular setting, risk of treatment failure and pharmacoeconomic considerations (Tables 3-5) .In addition, the panel fe lt that the stratification system for exacerbations developed by Anthonisen et al (7) was helpful.Type 1 exacerbations are characterized by increased dyspnea, increased sputum volume and purulence.Type 2 exacerbations are characterized by two of the above three symptoms.Type 3 exacerbations are characterized by one of the three symptoms and one other finding of fever, sore throat, nasal discharge, wheeze or cough.The efficacy of antibiotic therapy for Type 1 exacerbations of chronic bronchitis is well documented (7) .
In general, treatment failure suggests inflammation rather than infection, and the panel recommended sputum Gram stain and culture, and referral to a specialist for such cases.Group 5 -Bronchiectasis: Bronchiectasis is characterized by recurrent infections and ongoing sputum purulence.The panel recommended that patients in this group be referred for investigation and treatment.Patients should receive antibiotics tailored to the specific pathogens and the susceptibility of the pathogens found in the patient's sputum culture.Community-acquired pneumonia: Most patients with community-acquired pneumonia (CAP) can be managed as out-patients; however, CAP severe enough to warrant hospitalization has a mortality rate that may exceed 20% (8).Mortality is dependent on the extent of lung involvement, age, comorbidity and the need for mechanical ventilation.In nursing homes, the mortality rate may be as high as 40% (9).
For the majority of patients (Table 6), diagnostic information on the etiological agent is not available until several days after presentation.In most cases, sputum cultures are inconclusive, and it may be impossible to distinguish colonizing organisms from invasive organisms.Chest radiograph is often unhelpful in distinguishing among the common etiological causes of CAP (10) .Although microbiological evidence is preferred, the selection of an antibiotic is often made on the basis of epidemiological data, and clinical presentation and findings.
The Canadian Conference Group on Community-Acquired Pneumonia stratified CAP patients into four groups based on severity of illness, setting in which pneumonia developed, age, comorbidity and need for hospitalization (8).The recommendations presented here (Table 7) are based on their guidelines; local modification may be necessary to account for varying organism prevalence or antibiotic resistance profiles.These recommendations assume that documented evidence of pneumonia will be available during the course of treatment.
The panel also felt that nursing home patients should be considered separately because diagnosis and treatment are often unique in the nursing home setting.Patients with human immunodeficiency virus (HIV) and other forms of immunodeficiency were not included because these patients require consideration of a large number of opportunistic infections.Hospital-acquired pneumonia: Nosocomial pneumonia is the second most common hospital-acquired infection and the one that is most commonly fatal.The 6C overall mortality rate in Canada is estimated to be 32% (10).The incidence varies greatly depending on the type of medical service -Canadian tertiary care hospitals report incidence rates between 2.5 per 1000 admissions to the gynecology service and 67 per 1000 in the intensive care unit (8).Family physicians are rarely called upon to treat hospital-acquired pneumonia, and this condition was not addressed by the panel.

THE USE OF ANTIBIOTICS IN URINARY TRACT INFECTIONS AND PROSTATITIS
Thirty-five per cent of women aged 20 to 40 years will have at least one urinary tract infection (UT!) in their lifetime.In the general population, there are 25 times more UT!s in females than in males, although in institutional settings, the ratio is equivalent.
Over the past decade, the management of acute and recurrent cystitis and uncomplicated pyelonephritis has advanced, and there is now a general consensus on treatment (12).Conversely, there have been few advances in the management of complicated UT!s or chronic prostatitis, and antibiotic regimens for these conditions remain empirical (13).Acute uncomplicated UTI: Because the infecting organisms and their antimicrobial susceptibility profiles are predictable in young, healthy, nonpregnant females with typical symptoms of acute uncomplicated cystitis, pretreatment urine cultures are not recommended in this population.The diagnosis can be presumed if pyuria is present on microscopy or leukocyte esterase testing.A short course of empirical antimicrobial therapy can be prescribed.No follow-up visit or culture after therapy is necessary unless symptoms persist or recur.If pyuria is    It should be noted that resistance rates lo co-trimoxazole continue to rise and currently are in the order of 7 5% to 20% in the Canadian prairie provinces absent, or there are atypical clinical features or factors that suggest a complicated infection, a culture should be performed before therapy is started.In males, a culture is generally recommended.The efficacy of a three-day course of antibiotic is well documented (Table 8) (14)(15)(16)(17)(18).However, patients should BC be advised that some symptoms will not resolve immediately and may continue for more than three days.
Acute cystitis is very uncommon in young men.Sexual activity is a risk factor, whether the patient is heterosexual (19) or homosexual (20).Because of the relative rarity of the condition there are no controlled Ca n J Infect Dis Vol 8 Suppl C November/ Dece mber 1997 TABLE 9 Antibiotic treatment of recurrent cystitis treatment studies.A seven-day course of co-trimoxazole will cure most patients, and prolonged antibiotic therapy (four to six weeks of co-trimoxazole or a quinolone) is reserved for patients who develop recurrence (21) .Recurrent cystitis: Patients whose cystitis recurs after a three-day course of treatment for acute cystitis were stratified by the panel into two groups : those who relapse (early recurrence with the same organism within four weeks) and those who have reinfections.Patients who relapse should have culture and susceptibility testing performed and require a second seven-day course of treatment (Table 9).For patients with frequent reinfections (more than three in the preceding year), there are several options available -continuous low-dose prophylaxis (21)(22)(23)(24), postcoital prophylaxis (25)(26)(27) and intermittent self-therapy (28).Patient involvement is important in selecting the most appropriate strategy.Acute uncomplicated pyelonephritis: Symptoms of acute pyelonephritis are fever, flank pain and, in some cases, lower urinary tract symptoms.A midstream urine culture is recommended.In patients who are severely ill, are hemodynamically unstable, or have signs of septicemia or septic shock, hospital admission and parenteral therapy (Table 1 O) are indicated (29).If the patient fails to improve in 48 to 72 h, the likelihood of a complicated infection or a resistant pathogen must be considered.Investigation with a renal sonogram or computerized tomography should be considered in patients who are hemodynamically unstable or fail to improve.All patients should have a follow-up urine culture five to nine days after completion of therapy because there is a relapse rate of approximately 30%.Stable patients without nausea and vomiting can be managed safely with oral antibiotics on an out-patient basis (30).Acute pyelonephritis in pregnancy usually requires admission to hospital, and treatment with parenteral ampicillin and gentamicin (12).Quinolones are contraindicated in pregnancy.

Second-line Intravenous cefotaxime 1 g every 8 h Ceftriaxone g every 24 h
This regimen is to be followed by one with an oral antibiotic appropriate for use during pregnancy to complete a two-week course The recommendations defined below were derived from a substantial amount of clinical work in this area (31 -33) .Local resistance patterns must also be considered when choosing antibiotic therapy.Asymptomatic bacteriuria: Bacteriuria is common in the elderly, and the majority of patients are asymptomatic (34).Treatment is associated with a high inci-10C Dosage and duration 160/800 mg bid for 14 days 500 mg bid for 14 days 400 mg bid for 14 days 200 mg bid for 14 days 250/125 to 500/125 mg tid fo r 14 days 1.5 mg/kg/day intravenous 8 h or once daily (5 to 7 mg/kg/day) 1 to 2 g intravenous every 4 to 6 h 160/800 mg bid for 14 days 500 mg bid fo r 14 days 400 mg bid fo r 14 days 200 mg bid for 14 days dence of recurrence and may lead to development of antibiotic-resistant organisms (35).Untreated patients do not appear to have a higher morbidity or mortality rate.For this reason, asymptomatic infections are not routinely treated, although infections should be eradicated before genitourinary surgery or insertion of a prosthesis.In younger patients, the significance and management of asymptomatic bacteriuria is less clear.It should be eradicated in pregnant females, but repeated treatment of asymptomatic bacteriuria in healthy young females is not warranted (36).

Asymptomatic bacteriuria
No treatment except before instrumentation of the urinary tract or prosthetic surgery and during pregnancy.
UTI in pregnancy: Patients with UTis during pregnancy should be treated whether symptomatic or not (Table 11) (37).Approximately 30% of females with untreated asymptomatic bacteriuria in pregnancy develop acute symptomatic infection later in pregnancy, which may be associated with premature delivery (38) .The choice of antibiotics in pregnancy is limited, and quinolones are contraindicated (Table 12) (12,39,40) .Management of acute pyelonephritis in pregnancy usually requires admission to hospital and treatment with parenteral therapy, although out-patient therapy is safe and effective in selected patients.Catheter-associated UTI: Treatment of asymptomatic bacteriuria in patients with indwelling catheters has minimal benefit (41).Infection should be treated before urological surgery or insertion of a prosthesis (42).Within two weeks of catheter removal , 25% of untreated patients become symptomatic with either upper or lower UT! (43).
diagnosis of infection is often approximately 50% of febrile episodes in patients with in-   Antibiotics that may be used in pregnancy  dwelling catheters appear to originate from the urinary tract (44) .Parenteral treatment with ampicillin and gentamicin for 48 to 72 h until afebrile was recommended (12).

Grade D recommendations
Grade B recommendations for catheter-associated urinary tract infection (catheter in situ) • Asymptomatic bacteriuria -No treatment except before urological or prosthetic surgery • Symptomatic infection -Parenteral ampicillin and gentamicin until afebrile for 48 to 72 h Prostatitis: Acute prostatitis (Table 13) is a severe systemic illness characterized by a tender enlarged prostate, dysuria and urinary retention .Admission to hospital is often required.Stratification of chronic prostatitis has proven to be of limited value in developing guidelines for patient treatment.Diagnosis remains difficult because localization studies are time consuming, expensive and can cause discomfort to the patient.Treatment with antibiotics is moderately successful, and short term cure rates of 60% have been reported (45-4 7).The relapse rate following antibiotic treatment for chronic bacterial prostatitis is high.
The cause of chronic nonbacterial prostatitis is largely unknown.In the absence of inflammatory cells 12C in prostatic secretions or bacteriuria, prolonged antibiotic therapy is not indicated.Complicated UTis : UTls are associated with an underlying urinary tract abnormality, which may be caused by stones, recent urological surgery or renal cystic disease, or may be due to a significant systemic disorder such as diabetes, immunosuppression or a neurogenic bladder.There have been few controlled clinical trials, and therapy must be individualized according to presenting symptoms and comorbidity (12).The majority of patients are managed in the same way as those with acute pyelonephritis.Radiological investigation and urological consultation are often necessary.

ANTIBIOTIC TREATMENT OF DIABETIC FOOT INFECTIONS
Assessment and investigation: Diabetes mellitus affects close to 5% of the Canadian population, and foot infections are the most common reason for hospital admission among diabetics .At least half of the foot amputations performed each year are the result of diabetic foot infections ( 48) .
The pathogenetic processes leading to foot infection include peripheral neuropathy and occlusive vascular disease involving arteries in the lower third of the leg (49) , each of which are accelerated by poor diabetic control (50) .Recurrent (and unappreciated) trauma and re-  duced tissue perfusion increase the susceptibility of the foot to soft tissue infection, or to ulceration and chronic microbial colonization of foot lesions (51).Subsequent deeper infection of joints, bone or soft tissue planes may supervene.
Can J Infect Dis Vol 8 Suppl C November/ December 1997 When examining the infected foot (Table 14), the extent of cellulitis, necrosis and abscess formation and the presence of osteomyelitis must be assessed.A pedal pulse evaluation is important, and if the vascular system is compromised, further investigation with Doppler

USEO Y•DONOTCGn
ultrasound and angiography may be necessary.The chronic stable neuropathic foot ulcer, though colonized by microbes, seldom requires antimicrobial therapy.In this situation, treatment should be directed at relief from pressure and foot trauma (52).
Carefully obtained cultures are useful to guide antimicrobial selection.Superficial swabs are discouraged because surface contaminants are mixed with potential pathogens.More reliable cultures are collected from curettage material from a cleaned ulcer base, excised deep tissue or sinus cultures, particularly when probing of the sinus leads to subjacent bone (53).A wire swab, used elsewhere for urethral cultures, is a convenient tool to probe draining sinuses.When the wire probe leads to bone, there is an 89% predictive value for underlying osteomyelitis, a finding that reduces the need for nuclear imaging studies (53) .In cases of osteomyelitis, especially when necrotic bone is present, open debridement of infected tissue provides more reliable culture material.
Aerobic and anaerobic cultures usually reveal a polymicrobial infection, particularly in chronic and deep infections (51,54).Predominant pathogens include Staphylococcus aureus, anaerobic Gram-positive cocci, Bacteroides species, and enteric Gram-negative bacilli.
On the other hand, early acute infections are more likely to involve streptococcal and staphylococcal organisms as primary pathogens -Gram-negative organisms recovered from ulcer lesions are more likely colonizers in this situation (55) .Treatment: A team approach involving diabetology, diagnostic imaging, peripheral vascular surgery, orthopedic surgery, foot clinics and home care was recommended for the treatment of foot infections (56)(57)(58)(59)(60). Interventions include relief of trauma, pressure release, debridement of necrotic tissue, good diabetic control and referral to foot care.When indicated, vascular reconstructive surgery, including pedal bypass, was shown to reduce amputations and accelerate healing.Antibiotic therapy (Table 15) can be initiated empirically on clinical grounds, but subsequent therapy should depend on the type of pathogens recovered from cultures.
The duration of therapy of acute cellulitis is generally 10 to 14 days.If patients are started on intravenous therapy, stepdown to oral therapy should be considered once the infection is controlled (61).For patients with underlying osteomyelitis, prolonged therapy for as long as 12 to 15 weeks is required for durable cures (62,63) .Surgical debridement of dead bone is essential for cure.
Regarding the recommendations for antimicrobial therapy, equivalent outcomes are expected for each of the choices within each patient grouping.Ranking or selection is based on convenience, cost and adverse effect profiles.Enterococcal coverage may need to be considered when this organism is shown to persist in serial cultures from patients responding suboptimally, or when the organism is recovered in limb and lifethreatening infections .

First
mg bid for seven to 1 0 days 200 mg first day, th en 100 mg once da ily for seven to 10 days 250 to 500 mg tid for seven to 10 days If a course of first-line treatment fails, a second course with a different first-line antibiotic should be tried.Second-line antibiotics are indicated when first-line antibiotics have fa iled or there is a history of recent first-line failure Can J Infect Dis Vol 8 Suppl C November/ December •1997 uzzle: Guidelines for the family physician mg bid fo r three days 160/800 mg bid fo r seven days 100 mg bid for three days 50 to 100 mg qid for three days 250/125 mg tid fo r three days 100 to 250 mg bid fo r three days 200 mg bid fo r three days 400 mg bid fo r three days Second course of first-line (recurrence within four wee ks antibi oti c or of first infecti on) Urine culture required seco nd-line antibi oti c

Can J Infect Dis Vol 8
Suppl C Nove mber/ December 1997 Dose and duration Co-trimoxazole 40/ 200 mg on e dail y at bed lime or eve ry oth er night for six months If allergy to sulfa, nitrofurantoin 50 to 100 mg once daily at bed ti me or trimeth oprim •10 0 mg once daily al bedtime If intolerant or resistant, norfloxacin 200 mg once daily al bedtime Co-trimoxazole 40 to 80/ 200 lo 400 mg single dose If allergy to sulfa, nitrofurantoin 50 lo 100 mg single dose or cephalexin 25 0 mg single dose or ciprofloxacin 250 mg single dose Co-trimoxazole 32 0/ 1600 mg as a single dose or co-trimoxazole 160/800 mg bid fo r three days or any of th e aforementioned anti bioti cs fo r three days (grade D recommendati ons) Co-trim oxazole 160/800 mg bid fo r seven cl ays or trimeth oprim 100 mg bid for seve n cl ays or nitrofurantoin 50 to 100 mg qicl fo r seven cl ays Amox icillin/cl avulanate 25 0 to 500/125 mg lid for seven cl ays or ciprofl oxacin 25 0 mg bid fo r seven days or ofl oxacin 200 mg bid fo r seven cl ays or norfl oxacin 400 mg bid for seven days ro fl oxacin or ofl oxacin or doxycycl ine Ca n J Infect Dis Vol 8 Suppl C November/ December 1997

Antibiotic
Cephalex in 25 0 mg qi d fo r three to seve n days Ni trofurantoin 50 to 100 mg qid fo r three to seven days Concerns Ri sk of hemolyti c anemia in C6 PD defi cient pati ents Co-trimoxazole 160/800 mg bid fo r three to seven days Ri sk of kerni cleru s if used nea r lerm Amox icill in 250 to 500 mg tid fo r three to seven days Possible leral ogenesis High resistance rates It is recommended thal a follow-up urine sample be Laken Dose 1 to 2 g intraveno us every 4 to 6 h 3 to 5 mg/kg/day intrave nous every 8 h or 5 to 7 mg/kg/day once da ily 160/800 mg bid orally for fo ur Lo six weeks 500 mg bid orally fo r fo ur to six weeks 400 mg bid ora lly fo r fo ur to six weeks 300 mg bid orally fo r fo ur to six weeks •160/800 mg bid orall y fo r six lo 1 2 weeks 500 mg bid orally for six to 12 weeks 400 mg bid orally for six to 12 weeks 300 mg bid ora lly fo r six to 1 2 weeks 160/800 mg bid orally fo r fo ur to six weeks 500 mg bid orall y for fo ur to six weeks 25 0 to 500 mg bid orally fo r fo ur to six weeks 300 mg bid orally for fo ur to six weeks 100 mg bid orally for fo ur to six weeks Ca n J In fect D is Vol 8 Suppl C November/December 1997 USEC Y•DO

TABLE 2
Second-line antibiotic treatment for acute sinusitis CefixirneDose 250/125 to 500/1 25 mg tid for 10 to 14 days 500 mg bid for 10 to 14 days 500 mg first clay, th en 250 mg f r four cl ays 500 mg bid for •1 0 to 14 days 400 mg bid for 10 to 14 days 250 to 500 mg tid fo r 1 0 to 14 days 250 to 500 mg bid for 10 to 14 days 400 mg once daily for 10 to 14 days If second-line trea tment fails, refer patient to specialist.Other rea ons to consider referral are recurrent disease (grea ter than three episodes per yea r) and the development of complications such as mucoceles or orbita l extension

TABLE 3 Group 1 -
Acute bronchitis: Previously healthy patients with no other respiratory problems or comorbidity tr purulent sputum and/or fever is present, th e physician may consider prescribing an antibiotic.Amoxicillin, second generation cepha losporins or amoxicillin/clavulanate were not recommended because they fai l to provide coverage for Mycoplasrna pneurnoniae and Chl amyd ia pneumon iae. •

TABLE 5
Group 3 and 4 -Exacerbations of complicated chronic bronchitis: Patients with four or more exacerbations per year, fo rced expiratory volume in 1 s less than 50% predicted, older than 65 years of age or comorbid ity

TABLE 6
Suggested diagnostic tests for community-acquired pneumonia

TABLE 7 Antibiotic treatment of community-acquired pneumonia Grade D recommendation s Patient characteristics Group 1
Eryth romycin 1 giday in divided doses for 10 days If macrolide allergy, use doxycycline 200 mg firsl day, then 100 mg once daily for nine days If gastrointestinal inlolerance or a smoker, azilh ro mycin 500 mg firsl day, then 250 mg for four days or clarithromycin 250 to 500 mg bid for 10 days Amoxici llin/clavu lanale 500/125 mg tid for 10 days or cefaclor 500 mg Lid for 10 day or cefuroxime axetil 500 mg bid for 'IQ days If al lergic to penicillin, use co-trimoxazole 160/800 mg bid fo r 10 days If C pneumoniae or Legione/la species are a concern add Lo 450 mg tid w ith ciprofloxacin 500 Lo 750 mg bid for 10 days If C pneumoniae or Legione/la species are a concern, add erythromycin 2 giday in divided doses pneumoniae or Legionella species are a concern , add erythromycin 2 to 4 giclay in divided doses for 14 days Legionella species Can J In fect Dis Vol 8 Suppl C November/December 1997 Antibiotic recommendations erythromycin 2 giday in divided doses for 10 days or clarilhromycin 500 mg bid for 10 days or azithromycin 500 mg on day 1, then 250 mg daily for four days Amoxicillin/clavu lanate 500/125 mg Lid or cefuroxime axeti l 500 mg bid or cefaclor 500 mg tid or co-Lrimoxazole 160/800 mg bid If C pneumoniae or Legione/la species are a concern, add erythromycin •1 giday in divided doses In Lhe severely ill, use amoxicillin 500 mg Lid with ciprofloxacin 500 Lo 750 mg bid for 10 days or cefuroxime axeti l 500 mg bid for 10 clays with erythromy in 1 giday in divided doses If allergic to penicil lin, use clindamycin 300

TABLE 7 continued
Antibiotic treatment of community-acquired pneumonia *With the exception of ceftriaxone, the antibiotics may have to be adjusted for impaired renal (unction.Comorbidity: Chronic obstructive lung disease, diabetes mellitus, renal insufficiency, congestive heart failure, hospitaliza tion within previous year, postsplenectomy state, chronic alcoholism, malnutrition, altered mental status or suspected aspiration

Table 10
Antibiotic treatment of uncomplicated pyelonephritis:

TABLE 14
Investigation of diabetic foot infections

TABLE 15
Antibiotic treatment for diabetic foot infections Add metronidazole 250 to 500 mg bid for 7 4 days if patient responds suboptimally; tFor osteomyelitis *