Patients with a penicillin allergy are LEAST likely to have a cross-reaction with:
Allergy to antimicrobial agents must be considered prior to prescribing them. First, it is important to ascertain whether a patient has had any type of allergic reaction in association with administration of a particular antibiotic. However, one should take care to ensure that the purported reaction consists of true allergic symptoms and signs, such as urticaria, bronchospasm, or other similar manifestations, rather than indigestion or nausea. Penicillin allergy is quite common, the reported incidence ranging from 0.7 to 10%. Although avoiding the use of any beta-lactam drug is appropriate in patients who manifest significant allergic reactions to penicillins, the incidence of cross-reactivity appears low for all related agents, with 1% cross-reactivity for carbapenems, 5 to 7% cross-reactivity for cephalosporins, and extremely small or nonexistent cross-reactivity for monobactams.
What is the estimated risk of transmission of human immunodeficiency virus (HIV) from a needlestick from a source with HIV-infected blood?
While alarming to contemplate, the risk of human immunodeficiency virus (HIV) transmission from patient to surgeon is low. As of May 2011, there had been six cases of surgeons with HIV seroconversion from a possible occupational exposure, with no new cases reported since 1999. Of the numbers of health care workers with likely occupationally acquired HIV infection (n = 200), surgeons were one of the lower risk groups (compared to nurses at 60 cases and nonsurgeon physicians at 19 cases). The estimated risk of transmission from a needlestick from a source with HIV-infected blood is estimated at 0.3%.
Closure of an appendectomy wound in a patient with perforated appendicitis who is receiving appropriate antibiotics will result in a wound infection in what percentage of patients?
Surgical management of the wound is also a critical determinant of the propensity to develop an SSI. In healthy individuals, class I and II wounds may be closed primarily, while skin closure of class III and IV wounds is associated with high rates of incisional SSIs ( ~25-50%). The superficial aspects of these latter types of wounds should be packed open and allowed to heal by secondary intention, although selective use of delayed primary closure has been associated with a reduction in incisional SSI rates. It remains to be determined whether National Nosocomial Infections Surveillance (NNIS) system type stratification schemes can be employed prospectively in order to target specific subgroups of patients who will benefit from the use of prophylactic antibiotic and/ or specific wound management techniques. One clear example based on cogent data from clinical trials is that class III wounds in healthy patients undergoing appendectomy for perforated or gangrenous appendicitis can be primarily closed as long as antibiotic therapy directed against aerobes and anaerobes is administered. This practice leads to SSI rates of approximately 3 to 4%.
A chronic carrier state occurs with hepatitis C infection in what percentage of patients?
Hepatitis C virus (HCV), previously known as non-A, non-B hepatitis, is an RNA flavivirus first identified specifically in the late 1980s. This virus is confined to humans and chimpanzees. A chronic carrier state develops in 75 to 80% of patients with the infection, with chronic liver disease occurring in threefourths of patients who develop chronic infection. The number of new infections per year has declined since the 1980s due to routine testing of blood donors for this virus. Fortunately, HCV is not transmitted efficiently through occupational exposures to blood, with the seroconversion rate after accidental needlestick approximately 1.8%.
Possible exposure to anthrax should be initially treated with:
Inhalational anthrax develops after a 1- to 6-day in cubation period, with nonspecific symptoms including malaise, myalgia, and fever. Over a short period of time, these symptoms worsen, with development of respiratory distress, chest pain, and diaphoresis. Characteristic chest roentgenographic findings include a widened mediastinum and pleural effusions. A key aspect in establishing the diagnosis is eliciting an exposure history. Rapid antigen tests are currently under development for identification of this gram-positive rod. Postexposure prophylaxis consists of administration of either ciprofloxacin or doxycycline. If an isolate is demonstrated to be penicillin-sensitive, the patient should be switched to amoxicillin. Inhalational exposure followed by the development of symptoms is associated with a high mortality rate. Treatment options include combination therapy with ciprofloxacin, clindamycin, and rifampin; clindamycin added to blocks production of toxin, while rifampin penetrates into the central nervous system and intracellular locations.
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