INFECTIOUS DISEASESYMPTOMS/EXAM
■ CA-MRSA patients frequently present with skin or soft tissue infections
(especially nonhealing wound infections), but may develop necrotizing
pneumonia, necrotizing fasciitis, or rapidly fatal septicemia, endocarditis,
or osteomyelitis.
■ HA-MRSA infection is also most frequently found in skin and soft tissue
infections. It is also commonly found in the bloodstream, followed by the
lower respiratory and urinary tracts.
DIAGNOSIS
■ The most accurate methods are PCR to detect the mecAgene and latex
agglutination tests to detect the protein product of mecA, penicillin-binding
protein 2a.
■ Traditional culture and sensitivity techniques are acceptable, such as
oxacillin–salt agar screening plates and cefoxitin disk diffusion tests.
TREATMENT
■ CA-MRSA is typically responsive to a variety of common antibiotics, eg,
trimethoprim-sulfamethoxazole, rifampin, minocycline, doxycycline, lev-
ofloxacin, and clindamycin. Local sensitivities may vary.
■ Suspected HA-MRSA should be treated empirically with vancomycin. Pa-
tients unable to tolerate vancomycin or who develop vancomycin-resistant
MRSA may use linezolid or daptomycin.
■ Culture sensitivities should be reviewed when available to guide therapy.
■ Eradication of nasal colonization can be accomplished by using mupirocin
2% ointment 0.5 g in each nostril twice a day for 5 days.
Rabies
80% of cases in the United States attributed to bats
SYMPTOMS/EXAM
■ Incubation period: 30–90 days
■ Prodrome (days 1–4): flulike symptoms +pain/paresthesia at bite site (80%)
■ CNS involvement:
■ Agitation
■ Hydrophobia (violent inability to swallow)
■ Muscular spasms →paresis of mouth/periphery
■ Altered mental status/opisthotonos
DIFFERENTIAL
Other CNS infection (eg, encephalitis, meningitis), tetanus, cholinergic poi-
soning, Guillain-Barré, polio
DIAGNOSIS
■ ED=clinical (may see elevated CSF protein)
■ Final=postmortem brain analysis/CSF titers
Symptomatic rabies infections
are almost invariably fatal,
thus wound prophylaxis is the
key to surviving the disease.