INFECTIONS - Medicine for Mountaineering and Other Wilderness Activities - page 304

ample, streptococci commonly cause pharyngitis and skin infections and are usually sens-
itive to the penicillin family of antibiotics. Bacteria resistant to penicillins but susceptible
tothequinolonefamilyofantibioticscausetyphoidfeverandbacillarydysentery.Identify-
ing the organism causing an infection so that the most appropriate antibiotic can be admin-
istered is highly desirable but usually is not possible in the wilderness or in remote towns
and villages.
Toeradicateaninfection,antibioticsmustbegiveninquantitieslargeenoughtoproduce
blood and tissue concentrations that kill or inhibit the growth of the causative organisms.
Dose recommendations should be followed carefully. If nausea or vomiting prevents oral
administration, or the antibiotic is not effective when given orally, it must be administered
byintramuscularorintravenousinjection.Intravenousadministrationofdrugsandfluidsin
the field has become more feasible with the development of disposable, plastic administra-
tion sets and may be necessary when high blood concentrations of antibiotics are required,
as in meningitis.
Once therapy with an antibiotic has been started, it should be continued until organisms
have been killed and until all signs and symptoms of the infection have been absent for
several days. Treatment usually lasts from five to twenty days, depending on the infection.
Shorter courses of therapy may result in relapse.
Antibiotics should not be given prophylactically to prevent infections except under spe-
cial circumstances. For example, most individuals with colds or minor wounds should not
be given an antibiotic to prevent pneumonia or a wound infection. Administration of an-
tibiotics in this manner does not prevent subsequent infection, and it may allow resistant
organisms to multiply and produce an infection that becomes difficult to treat.
Two frequently used families of antibiotics are the cephalosporins and the penicillins.
Penicillin V (Pen Vee K® and others) and cephalexin (Keflex® and others) are well-ab-
sorbed orally. If intramuscular injection is necessary, procaine penicillin G is used. The in-
travenous preparation of penicillin is aqueous or crystalline penicillin G, and a frequently
used intravenous cephalosporin is ceftriaxone (Rocephin®). Cephalexin is given orally for
less severe staphylococcal infections, except for those caused by strains of staphylococci
thataremethicillinresistant.Ampicillin,cephalexin,andciprofloxacinareusuallyeffective
against organisms that produce urinary tract infections. Trimethoprim-sulfamethoxazole
(TMP-SMX,Bactrim,Septra®,andothers),acombinationoftwoagents,oneofwhichisa
sulfonamide, is useful for treating a wide variety of infections, including typhoid fever and
bacillary dysentery, urinary tract infections, skin infections, and pneumonia. Ciprofloxacin
(Cipro®) and levofloxacin (Levaquin®) are quinolones that have a special role in bacil-
lary dysentery, urinary tract infections, and traveler's diarrhea. Because it affects growing
bones, ciprofloxacin should not be given to children.