also be seen in soldiers, given the conditions prevalent in intensive-care units (ICUs) and hospital wards when universal precautions are not adhered to.

Concerns Regarding Acinetobacter baumannii

One condition that is more prevalent in OEF and OIF troops than in civilian settings is infection with Acinetobacter calcoaceticus-baumannii complex, a well-recognized cause of wound infection in general and among military troops in particular (CDC 2004; Davis et al. 2005). The complex is also a cause of nosocomially-acquired infection when wounded, infected soldiers are intermingled with other patients in the ICU, emergency room, or hospital ward. Acinetobacter spp. infection has been discovered in wounds from OEF and OIF and in European and American hospitals because of nosocomial transmission (CDC 2004; Davis et al. 2005; Joly-Guillou 2005). It is likely that wound infections become a nidus for nosocomial transmission to others, particularly in an ICU setting, because of suboptimal handwashing by hospital personnel (Joly-Guillou 2005). A. baumannii is the species isolated most often.

Acinetobacter spp. infection was described decades ago as a cause of postsurgical urinary tract infections, but in the early 21st century is seen more often as an extremity wound infection, a respiratory tract infection, or bacteremia (CDC 2004; Davis et al. 2005; Joly-Guillou 2005). The human body louse has been reported to be a likely vector (La Scola and Raoult 2004). Multiple-drug-resistant A. baumannii has been reported in troops deployed in OIF and OEF (CDC 2004; Davis et al. 2005; Zapor and Moran 2005), in Israelis hospitalized in Tel-Aviv (Abbo et al. 2005), in patients in a Brazilian tertiary referral hospital (Reis et al. 2003), and in South Korean hospital patients (Lee et al. 2003). Environmental sources are ubiquitous, including soil and river water worldwide, including in the United States (Ash et al. 2002). Examples of extremity infections include osteomyelitis, postburn lesions, open fractures, and deep wounds. The origin of Acinetobacter spp. infection can therefore be the original soil contamination due to the injury, a hospital, or, very rarely, a community source unrelated to a known wound. A patient’s history and epidemiologic circumstances can indicate which source is most likely to be responsible.

Although most Acinetobacter spp. infections are not life-threatening, multiple-drug-resistant strains are now prevalent among US military troops returning from OEF and OIF (CDC 2004; Davis et al. 2005). Extended use of combination antibiotics to which the organisms are sensitive was successful in curing all patients in a case series of 23 infected US soldiers reported in 2005 (Davis et al. 2005). Among the 38 isolates obtained from these 23 men, susceptibility varied from 3% to 29% for amoxicillin-clavulanate, cefepime, cefotetan, ceftazidime, ceftriaxone, ciprofloxacin, gentamicin, tobramycin, and trimethoprim and sulfamethoxazole. About half the 38 isolates were sensitive to amikacin and to ampicillin and sulbactam. Imipenem was effective against 89% of the multiple-drug-resistant strains. Colistin was effective against 100%, but only three isolates were tested (Davis et al. 2005). To minimize the risk of nosocomial A. baumannii spread, Iraqi-based US military facilities now isolate new wound patients until results of colonization swabs are known (Davis et al. 2005). Earlier generation antibiotics that are not in widespread current use (including colistin and polymyxin B) have been administered to multiple-drug-resistant A. baumannii patients. However, A. baumannii resistant to polymyxin B was reported in Brazil in 2003 (Reis et al. 2003).

The Brooke Army Medical Center experience in San Antonio suggested a median of 6 days and a maximum of 12 days between an OIF- or OEF-acquired war injury and the presentation of Acinetobacter spp. in a defined wound or bone infection (bone, draining

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