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Gonorrhea is caused by Neisseria gonorrhoeae. For men, classic manifestations of gonorrhea include urethritis and oropharyngeal exudates with lymphadenopathy. In women, classic manifestations are cervicitis, infertility, ectopic pregnancy, chronic pelvic pain, and pelvic inflammatory disease, but women commonly may be asymptomatic. Nucleic acid amplification test is preferred for diagnosing genital and extragenital gonococcal infections. Ceftriaxone cures about 98%-99% of uncomplicated gonorrhea infections, but dual treatment with ceftriaxone and azithromycin is recommended. Retesting is recommended 3 months after treatment because patients with gonorrhea constitute a high-risk group with potential for reinfection.

Fungal infections within the central nervous system (CNS) occur more commonly in patients with immunosuppressive conditions but occasionally are diagnosed in immunocompetent patients as well. This may reflect the route of infection and the specific pathogen. Fungal infections resulting from hematogenous seeding are typically encountered in patients with profound and prolonged immunosuppression (including neutropenia); however, pathogens such as Cryptococcus gattii and some dimorphic fungi can also produce CNS disease in otherwise healthy persons. A common avenue of infection in immunocompetent patients is traumatic or nosocomial inoculation, including neurosurgical procedures, foreign body implants, and contaminated spinal fluid injections.

The medical management of infectious diseases and antimicrobial therapy can be a daunting task for health care professionals. Although expansive textbooks and online resources are available, we believe that a more simplified, quick reference guide is needed for the day-to-day office and hospital clinical practice. This book is designed to provide information about infectious diseases and antimicrobial therapy in a format that is readily accessible and easily applicable to the clinical environment. Highlights of this book include simplified and thorough drug dosing recommendations for renal function and renal replacement therapies, drugs of choice for specific organisms (including bacteria, fungi, and viruses), and simplified antimicrobial and management recommendations for specific infectious syndromes.

This section contains tables covering spectrum of activity, preferred treatment and alternate treatment options various classes of bacteria, fungi, and viruses. Bacterial drug resistance issues are also reviewed.

The medical management of infectious diseases and antimicrobial therapy can be a daunting task for health care professionals. Although expansive textbooks and online resources are available, we believe that a more simplified, quick reference guide is needed for the day-to-day office and hospital clinical practice. This book is designed to provide information about infectious diseases and antimicrobial therapy in a format that is readily accessible and easily applicable to the clinical environment. Highlights of this book include simplified and thorough drug dosing recommendations for renal function and renal replacement therapies, drugs of choice for specific organisms (including bacteria, fungi, and viruses), and simplified antimicrobial and management recommendations for specific infectious syndromes.

This section contains tables and text covering pediatric and neonatal antimicrobial dosing for an extensive list of antimicrobials, vancomycin, and aminoglycosides. Adjustments needed for patients with renal impairment, infusion rates, and monitoring are also included.

This section contains tables covering fundamentals for an extensive list of antimicrobials. Pharmacokinetics, drug levels, toxicity, clinical monitoring, antimicrobials, laboratory monitoring are reviewed.

This section contains tables and text covering an exhaustive group of infectious syndromes including respiratory tract infections, infective endocarditis, intravascular catheter-related infections, central nervous system infections, urinary tract infections, soft-tissue infections, osteomyelitis, gastrointestinal infections, tick-borne infections, tuberculosis, sexually transmitted diseases, HIV, hepatitis, and fungal and zoonotic infections. Vaccination schedules, travel medicine, and bioterrorism are also reviewed.

•Clinical: The diagnosis of meningitis is suggested by the constellation of headache, fever, and neck stiffness. Some patients may also experience changes in mental status.•Radiology: Computed tomograms or magnetic resonance imaging of the brain may be indicated for immunocompromised patients and patients with papilledema or focal neurologic deficits. However, neuroimaging should not delay initiation of antimicrobial therapy....

• Peritoneal infection without an obvious source• Adult patients with cirrhosis and ascites (higher risk: gastrointestinal [GI] bleeding, previous spontaneous bacterial peritonitis [SBP], or low protein concentration in ascitic fluid) or, occasionally, congestive heart failure, malignancy, or connective tissue disease• Pediatric patients with postnecrotic cirrhosis, nephrotic syndrome, or urinary tract infections...

• Obtain confirmatory human immunodeficiency virus (HIV) testing by rapid test or enzyme-linked immunosorbent assay (ELISA); optimally repeat HIV viral load (VL) and CD4 T-cell (CD4) count 2 times before initiation of therapy; a substantial change in CD4 count is generally >30%• Perform VL immediately before treatment initiation (or change in therapy) and again 2–8 weeks later; for the latter, the optimal decrease would be at least 1 log...

•Clinical: Acute monoarticular swelling, typically of a large joint, with fever and pain•Radiology: Normal osseus structures (early) with soft-tissue swelling•Laboratory: Elevated leukocytes, erythrocyte sedimentation rate, and C-reactive protein•Arthrocentesis: >50,000–100,000 leukocytes (predominantly neutrophils), absence of crystals, Gram stain often negative...

• Viridans streptococci•Staphylococcus aureus• Enterococci• HACEK organisms• Same as native valves, plus• Coagulase-negative staphylococci• Fungi• Gram-negative rods (early postoperative period)The diagnosis of infective endocarditis (IE) rests on demonstrated evidence of cardiac involvement and persistent bacteremia due to microorganisms that typically cause endocarditis. Establishing a microbiologic diagnosis is critical to therapeutic decisions. Every effort should be made to identify the causative organism....

• Human immunodeficiency virus (HIV) transmission risk is about 0.3% (about 1 in 300)• About 0.1% after mucous membrane exposure• • Hepatitis B virus (HBV) for nonvaccinated persons when blood from source is:• HBsAg (hepatitis B surface antigen) positive ...

•Risk factors: Ubiquitous organism; CD4 count •Clinical disease• Exertional dyspnea, fever, nonproductive cough, and chest discomfort that gets worse over days to weeks• Hypoxemia; chest radiographs vary (most commonly show diffuse bilateral, symmetrical interstitial infiltrate but may be relatively normal early in course and can have atypical presentation)...

Several protocols exist, but this is the one used at Mayo Clinic. (See also guidelines that follow for pulse [extended-interval or once-daily] dosing.)Creatinine clearance (ClCr) calculation: Males: (140−age[y])×(weight[kg])...

•Ludwig angina: Acute soft tissue infection usually of dental origin; spreads rapidly and is bilateral; involves submandibular and sublingual spaces and can spread to the neck; may include respiratory obstruction from edema•Acute necrotizing ulcerative gingivitis (eg, Vincent angina, trench mouth): Mixed bacterial infection with gingival ulcerations and gingival breakdown, usually due to poor dental hygiene...

•Group I (photochromogens): Produces pigment in light: Mycobacterium kansasii, M marinum, M simiae•Group II (scotochromogens): Produces pigment in dark: M scrofulaceum, M szulgai, M xenopi, M gordonae•Group III (nonphotochromogens): No pigment: M avium-intracellulare complex (MAC), M haemophilum, M ulcerans, M malmoense, M terrae...

Numerous species of ticks have been associated with transmission of infectious diseases to humans. Recognizing the type of tick and its geographic distribution can aid identification of select bacterial, viral, and protozoan infection risk assessment.• Consists of the hard ticks that transmit nearly all tick-borne human diseases; 2–30 mm...

• Abrupt-onset, purulent urethral discharge and dysuria are more common with Neisseria gonorrhoeae than with Chlamydia trachomatis and other nongonococcal urethritis (NGU) pathogens• Mucopurulent or purulent urethral discharge and dysuria, which can occur with any pathogen, often impede clinical distinction• Gram stain of urethral discharge shows >5 leukocytes per high-power field (HPF)...

•General information: Four species are known to cause disease in humans: B abortus (cattle), B canis (kennel-raised dogs), B melitensis (goats and sheep), and B suis (swine)•Geographic distribution: Mediterranean (eg, Spain, Italy, Greece), Latin America, Middle East (eg, Saudi Arabia, Syria, Iraq, Kuwait)...

Surgical prophylaxis should be directed toward the microorganism likely to cause infection after the operation.• Infusion just before incision is critical to success but continuation beyond a 24-hour maximum (48-hour maximum for cardiac surgery) is not necessary; resistance and complications may result from prolonged use of prophylaxis...

• Neonate: Full-term newborn 0–4 weeks postnatal age• Infant: 1 month to 1 year of age• Child: >1 year to 12 years of age• Adolescent: 13–18 years of age• Adult: >18 years of ageThe following tables do ...

•Clinical: Localized pain and tenderness of involved bone; systemic signs and symptoms of acute hematogenous osteomyelitis•Radiology: Bone destruction or sequestrum in chronic cases; use of nuclear scanning, magnetic resonance imaging, or computed tomography may aid diagnosis and staging•Laboratory: White blood cell count is often normal; erythrocyte sedimentation rate and C-reactive protein are usually elevated...

(See also section on Soft Tissue Infections: Necrotizing or Toxigenic, pages 206-209.)• Diagnosis is largely based on history and physical examination.• Recurrent cellulitis is common (≥20% of patients).• Leukocytosis may or may not be found.• Blood cultures have low yields (about 2–4%)....

The guidelines for the prevention of infective endocarditis (IE) issued by the American Heart Association underwent a major revision in 2007. Key changes include the following: • Dental procedures have been found to be associated with a small number of cases of IE. Thus, even if prophylaxis was 100% effective, it would prevent only an extremely small number of cases....

The recommended immunization schedule for those 0–6 years is presented in Figure 5. For those who fall behind in the immunization schedule or start late, see the catch-up schedule available on the CDC Web site: http://www.cdc.gov/vaccines/recs/schedules/downloads/child/catchup-schedule-praHepatitis B (HepB) vaccine. (Minimum age: Birth.) •...

• Insect bite precautions are essential.•DEET (N,N-diethyl-meta-toluamide) or picaridin-containing insect repellents• Concentration: A DEET concentration of 20–50% is safe for both adults and children >2 months of age. A DEET concentration of >50% is NOT recommended because it affords no additional benefit....

This chapter approaches the field of infectious diseases from 3 perspectives. This third section reviews antimicrobial agents. The mechanisms of action, spectrums of activity, clinical uses, routes of excretion, and toxic effects of various antimicrobial agents are emphasized. Antibacterials such as penicillins, cephalosporins, carbapenems, aminoglycosides, tetracyclines, and fluoroquinolones are reviewed. Antifungals such as the azoles, polyenes, and echinocandins are also covered. Antivirals such as acyclovir, famciclovir, oseltamivir, and foscarnet are included as well.

• A high index of suspicion is critical in the diagnosis of necrotizing or toxigenic soft tissue infections.• Minor or major trauma can predispose patients to necrotizing soft tissue infections, which are more common in obese patients, patients with diabetes mellitus, and immunocompromised patients....

(Note: Several vancomycin dosing and monitoring protocols exist; this is the one used at Mayo Clinic.)•Loading dose: Consider 20–30 mg/kg, especially in critically ill patients with serious infections such as meningitis, health care–associated pneumonia, or endocarditis.•Maintenance dose: Give 15–20 mg/kg based on actual body weight for most patients (20 mg/kg is reasonable when aiming for a trough range of 15–20 mcg/mL). Adjust based on serum levels. See also the following sections on hemodialysis and continuous renal replacement therapy....

•Candida•Cryptococcus neoformans and C gattii• Other: Saccharomyces, Trichosporon, etcTwo different growth forms: Outside the body (25°C), they grow as a mold, producing hyphae and having asexual reproduction of spores; inside the body (37°C), they grow in a yeast form...

Diagnostic criteria include productive cough, symptoms of upper respiratory infection, and negative findings on chest radiographs. Viral agents are the most common cause; antibiotics are therefore not beneficial.•Viral causes: Influenza, parainfluenza, and other respiratory viruses affect >70% of patients•Less common but potentially antibiotic-responsive infectious agents...

Information in the following tables does NOT apply to the dosing of antimicrobials in neonates.• Measure vancomycin serum levels (trough) in cases of:• Unstable or changing renal function• Administration of other nephrotoxic drugs• Positive blood cultures or other cultures...

• Catheter cultures should be performed only if a catheter-related bloodstream infection (CRBSI) is suspected. Do NOT obtain routine or surveillance blood cultures through catheters.• Always draw peripheral and blood cultures through the catheter lumen before starting empiric antimicrobial therapy.A definite diagnosis of CRBSI requires one of the following: ...

The following tables do NOT apply to the dosing of antimicrobials in neonates.

•Define the host: Identify factors that influence the type of infection, disease progression, and prognosis, which include:• Host factors such as patient age, immune status (eg, immunosuppression or the absence of a spleen), the presence of foreign bodies (eg, central venous catheter, permanent pacemaker, intracardiac defibrillator, prosthetic heart valves, prosthetic joints), or other comorbid conditions, ...

• Group of mycobacteria causing tuberculosis (TB) in mammals• Composed of Mycobacterium tuberculosis, M bovis, M africanum, M microti, M canetti, and M mungi; producing similar clinical TB in mammals•M tuberculosis causes TB in humans, whereas other species predominantly cause disease in animals...