Treatment of Specific Infections and Miscellaneous Antibiotics

Chapter 58


Treatment of Specific Infections and Miscellaneous Antibiotics






Therapeutic Overview


The student and the beginning clinician may be overwhelmed by the numerous antibiotics that are available. Table 58-1 serves as a general summary of common offending organisms for various infections. Both the first treatment choice and the alternative treatment suggestions listed are based on a compendium of various authorities.



TABLE 58-1


Empirical Antimicrobial Treatment∗

















































































































































































































































Site of Infection Usual Causes First-Choice Treatment, Oral Alternative Treatments
SKIN AND SOFT TISSUE
Impetigo S. aureus and group A strep dicloxacillin mupirocin topical, azithromycin, clarithromycin, erythromycin, oral cephalosporin second generation (cephalexin)
Cellulitis, extremities Group A strep, occasionally group B, C, and G; S. agalactiae TMP/SMX 250-500 mg bid po in areas where MRSA isolates account for 15% of infections erythromycin, AM/CL azithromycin, clarithromycin, clindamycin, levofloxacin
ANIMAL BITES
Cat P. multocida, S. aureus AM/CL 875 mg bid or 500 mg tid cefuroxime 500 mg q12h, doxycycline 100 mg bid
Dog P. multocida, P. canis, S. aureus, Bacteroides spp, Fusobacterium AM/CL 875 mg bid or 500 mg tid Adults: clindamycin 300 mg qid plus Cipro 500 mg bid
Children: clindamycin 8-16 mg/kg/day plus TMP/SMX
Human S. viridans, S. epidermidis, Corynebacterium, S. aureus, Eikenella, Bacteroides AM/CL 875 mg bid × 5 days clindamycin, either ciprofloxacin or TMP/SMX
Infected postoperative wound S. aureus, group A strep, Enterobacteriaceae Oral cephalosporin, first generation or AM/CL dicloxacillin
RESPIRATORY
Otitis media
No antibiotics in past month		 S. pneumoniae, H. influenzae, M. catarrhalis, group A strep, Enterobacteriaceae amoxicillin azithromycin, clarithromycin
Antibiotics in past month   amoxicillin, AM/CL, cefdinir, cefpodoxime, cefprozil, or cefuroxime  
ACUTE SINUSITIS
No antibiotics in past month S. pneumoniae, H. influenzae, M. catarrhalis amoxicillin, AM/CL, cefdinir, cefpodoxime, cefuroxime × 10 days clarithromycin, azithromycin, TMP/SMX, doxycycline, or fluoroquinolones
Antibiotics in past month   AM/CL or fluoroquinolones (adults) × 10 days  
Treatment failure   Mild to moderate: AM/CL + extra amoxicillin or cefpodoxime, cefuroxime, or cefdinir Severe: gatifloxacin, levofloxacin, moxifloxacin
Pharyngitis Group A, C, G strep, C. diphtheriae, A. haemolyticum, M. pneumoniae penicillin V po × 10 days; oral first-generation cephalosporin in areas of high resistance Erythromycin x 10 days, oral cephalosporin second generation × 4-6 days, clindamycin or azithromycin × 5 days, clarithromycin × 10 days
Acute bacterial exacerbation of COPD S. pneumoniae, H. influenzae, M. catarrhalis Mild: No antibiotics Moderate: amoxicillin, doxycycline (TMP/SMX), cephalosporin Severe: AM/CL, azithromycin, clarithromycin, oral cephalosporin, fluoroquinolones with enhanced activity vs. S. pneumoniae
PNEUMONIA
Ages 1 to 3 months C. trachomatis, RSV virus, Bordetella erythromycin IV  
Ages 1 to 24 months S. pneumoniae, H. influenzae, chlamydia, mycoplasma cefuroxime IV  
Ages 3 months to 5 years S. pneumoniae, mycoplasma, chlamydia erythromycin, clarithromycin, azithromycin  
Ages 5 to 18 years Mycoplasma, S. pneumoniae, C. pneumoniae clarithromycin 500 mg bid, azithromycin doxycycline, erythromycin
Ages 18 years and older Mycoplasma, chlamydia, S. pneumoniae, Legionella, H. influenzae, K. pneumoniae azithromycin, clarithromycin, doxycycline fluoroquinolone with enhanced activity vs. S. pneumoniae, oral cephalosporin second generation, AM/CL, doxycycline
PROPHYLAXIS FOR PROCEDURES
Dental, esophageal, and URI procedures Streptococcus viridans, other streptococci, enterococci, staphylococci amoxicillin 2 g, children 50 mg/kg 1. clindamycin 600 mg, children 20 mg/kg
2. cephalexin 2 g, children 50 mg/kg
3. azithromycin or clarithromycin 500 mg, children 15 mg/kg
Gastrointestinal (excluding esophageal) and genitourinary procedures Enteric gram-negative bacilli, anaerobes, enterococci amoxicillin 2 g, children 50 mg/kg IV gentamicin or vancomycin
GI INFECTIONS
Mouth Oral microflora infection, polymicrobial clindamycin 300-450 mg q6h AM/CL 875 mg bid or 500 mg tid
Gastroenteritis Usually viral; amebiasis, L. monocytogenes, V. cholerae Culture, treat cause  
Diarrhea, traveler’s E. coli, shigella, salmonella, Campylobacter, C. difficile, amebiasis Mild: ciprofloxacin 750 mg × 1 dose
Severe: fluoroquinolone bid × 3 days		 azithromycin usual dose, or 1000 mg x 1 dose
Amebiasis, giardiasis: tinidazole 2000 mg po × 3 days
Diarrhea, severe Shigella, Salmonella, C. jejuni, E. coli 0157 H7, E. histolytica, C. difficile fluoroquinolone (Cipro) 500 mg q12h × 5-7 days
metronidazole 500 mg tid × 10-14 days		 TMP/SMX bid (resistance common)
vancomycin 125 mg qid po × 10-14 days; first choice if moderately to severely ill
Diverticulitis Enterobacteriaceae, P. aeruginosa, Bacteroides spp, enterococci TMP/SMX bid or ciprofloxacin 500 mg bid metronidazole 500 mg q6h × 7-10 days AM/CL 500 mg tid po × 7-10 days
RENAL/GU
UTI E. coli, S. saprophyticus, enterococci Force fluids and flush for 24 hours. Then TMP/SMX × 3 days, fluoroquinolone × 3 days if still symptomatic. nitrofurantoin, fosfomycin, oral cephalosporin, doxycycline, amoxicillin
Pyelonephritis E. coli, S. saprophyticus, enterococci fluoroquinolone × 7 days AM/CL, oral cephalosporin, TMP/SMX DS
VAGINAL INFECTIONS
Candidiasis C. albicans Vaginal antifungals × 3-7 days; see separate table Immediate-relief fluconazole plus azole or hydrocortisone cream; fluconazole 150 mg po × 1 dose
Severe: fluconazole × 2 days plus 7 days azole
Chronic: terconazole × 14 days; if resistant, switch to a more potent preparation
Bacterial vaginosis Gardnerella, Bacteroides, others metronidazole 500 mg bid × 7 days metronidazole 2 g × 1 dose clindamycin
Trichomonas T. vaginalis tinidazole (Tindamax ) 2000 mg po × 1 day metronidazole
PROSTATITIS
Acute N. gonorrhoeae or C. trachomatis Use 160 mg TMP and 800 mg SMX bid (or Septra DS bid or Bactrim DS 1 bid) Fluoroquinolones (ciprofloxacin 250-500 mg po bid or ofloxacin 400 mg po bid)
Chronic E. coli, Klebsiella, P. mirabilis, P. aeruginosa, E. faecalis Fluoroquinolones (ciprofloxacin 250-500 mg po bid or ofloxacin 400 mg po bid) Use 160 mg TMP and 800 mg/SMX bid (or Septra DS bid or Bactrim DS 1 bid)
STDs
Gonorrhea N. gonorrhoeae ceftriaxone 250 mg IM single dose cefixime 400 mg po in single dose (not for girls younger than 12) or single-dose injectable cephalosporin regimens plus azithromycin 1 g po in a single dose or doxycycline 100 mg/day × 7 days
Ophthalmia neonatorum Prophylaxis for N. gonorrhoeae erythromycin (0.5%) ophthalmic ointment into both eyes once at birth  
Chancroid Haemophilus ducreyi azithromycin 2 g po in a single dose ceftriaxone 250 mg IM in a single dose OR ciprofloxacin 500 mg po bid × 3 days or erythromycin base 500 mg po tid × 7 days.
Syphilis T. pallidum benzathine penicillin G 2.4 million units IM × 1 dose is the preferred treatment for all stages of syphilis doxycycline 100 mg po bid × 14 days or tetracycline 500 mg po qid × 14 days may be used for those allergic to penicillin.
Chlamydia C. trachomatis azithromycin 1 g × 1 dose, doxycycline 100 mg bid × 7 days erythromycin base 500 mg qid × 7 days, erythromycin ethylsuccinate 800 mg qid × 7 days, difloxacin 300 mg bid × 7 days, levofloxacin 500 mg qd × 7 days
Granuloma inguinale (donovanosis) Calymmatobacterium granulomatis doxycycline 100 mg po bid × 21 days is standard treatment  
FEMALE REPRODUCTIVE
Mastitis S. pneumoniae, S. pyogenes, S. aureus, H. influenzae, P. aeruginosa dicloxacillin 500 mg q6h clindamycin 300 mg q6h
SYSTEMIC FEBRILE
Lyme disease B. burgdorferi doxycycline 100 mg bid × 10-14 days; or amoxicillin 500 mg tid, cefuroxime 500 mg bid × 14-21 days erythromycin 250 mg qid
Rocky Mountain spotted fever R. rickettsii doxycycline 100 mg po bid × 7 days chloramphenicol 50 mg/kg/day IV q6h × 7 days


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AM/CL, Augmentin.


Fluoroquinolones with enhanced activity vs. S. pneumo: gatifloxacin, levofloxacin, and moxifloxacin.


∗Treatment recommendations, dosages, and therapy may vary, depending on age, pregnancy, or lactation. Consult the latest CDC recommendations at www.CDC.gov.


This chapter presents antimicrobial therapy according to disease- or site-specific recommendations. Treatments presented include recommendations for both children and adults when available. These are general guidelines for simple infections, with no complicating factors. See up-to-date specific drug information and check dosages before prescribing, especially for children and the elderly, because recommendations often vary with changing resistance patterns.



Skin and Soft Tissue Infections, Including Impetigo


Guidelines are provided by the Infectious Diseases Society of America (www.idsociety.org):



Impetigo is a contagious infection of the skin that is common in children. The lesions are macules, vesicles, bullae, pustules, and honey-colored crusts that usually appear on the face and other exposed skin. Systemic antibiotics usually are required. However, mupirocin (Bactroban) can be used for topical treatment of mild impetigo.



SSSI guidelines from the Infectious Diseases Society of America suggest vancomycin and telavancin for hospitalized patients with methicillin-resistant Staphylococcus aureus (MRSA).



Cellulitis


Although most cellulitis seen in primary care is easily treated, the provider must rule out the following complicated patients for whom they should seek referral:



• Cellulitis, erysipelas: Group A strep, occasionally group B, C, or G; Streptococcus pyogenes, S. aureus (uncommon)


• Necrotizing fasciitis, “flesh-eating bacteria”: Usually polymicrobic with gram-positive and gram-negative and anaerobic; groups A, C, and G strep, Vibrio, enterococci, staphylococci, Escherichia coli, Pseudomonas, Proteus, Serratia, Clostridium. These patients require hospitalization.


• Diabetic: Group A strep, S. aureus, Enterobacteriaceae, clostridia (rare). Patients often are complicated and require hospitalization. Treatment usually is provided until 3 days after resolution of inflammation.


• S. aureus remains a possibility and should be considered if first-line treatment is not successful. Culturing an open wound seldom produces useful information; often the report comes back with multiple organisms. Site of infection and how infection was acquired will often reveal the most likely causative organism. Community-acquired MRSA infection is increasingly common; it should be diagnosed early and treated with medications such as Septra or doxycycline. Vancomycin has become the standard in areas where MRSA infections exceed 15% of the isolate. Alternatives to vancomycin also should be considered so widespread vancomycin resistance may be delayed, if possible. Consider levofloxacin, tetracycline, clindamycin, rifampin, gentamicin, linezolid, daptomycin, and tigecycline. Consult the latest CDC guidelines regularly for recommendations as they are issued.



Animal Bites




The location and type of the wound are important factors, as is the type of animal, in selection of appropriate treatment for the bite wound. Unprovoked animal bites should raise the suspicion of rabies. Cat bites are more likely to become infected than are human or dog bites. Human bites by children are not likely to become infected; infection is more likely with bites by adults. Dog bites are very unlikely to become infected.


Give the patient a tetanus/diphtheria booster if not vaccinated within the previous 5 years. Do not suture/glue the wound closed if it has been longer than 12 hours since the bite occurred, or if the injury is a hand wound or a cat bite. Prophylaxis is recommended for bites on the hand or in the genital region, for human or cat bites, for crush and puncture wounds, and for the treatment of patients with impaired immune systems.




Respiratory Tract Infections


By far, the most common causative agent is a virus, which causes an acute self-limiting disease that should not be treated with an antibiotic. Influenza is caused by a virus and can be treated with the drugs listed in Chapter 15. Evidence suggests that antibiotics, especially broad-spectrum antibiotics, continue to be overused for adult URIs.



Otitis Media




Signs and symptoms that indicate a need for antibiotic treatment include otalgia, fever, otorrhea, or a bulging yellow or red tympanic membrane. Simple effusion (i.e., presence of fluid in the middle ear with no signs or symptoms of acute infection) does not have to be treated with antibiotics. Much controversy has arisen about treatment with antibiotics in the past. However, doctors and patients are becoming comfortable with the new approach of treating with an antibiotic only if clearly indicated. Patients with tympanic membrane perforation, chronic or recurrent infection, craniofacial abnormalities, or immune compromise should be referred to an ENT specialist for treatment. How recently the patient has been treated with antibiotics will affect the antibiotic choice.

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Jul 22, 2016 | Posted by in PHARMACY | Comments Off on Treatment of Specific Infections and Miscellaneous Antibiotics

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