Heather C. Yun

Osteomyelitis in Military Personnel Wounded in Iraq and Afghanistan

BACKGROUND Orthopedic injuries occurring in Operations Iraqi Freedom and Enduring Freedom (OIF/OEF) are complicated by infections with multidrug resistant bacteria. We describe demographics and microbiology of OIF/OEF casualties with primary and recurrent osteomyelitis. METHODS A retrospective cohort study was performed of OIF/OEF casualties admitted to our facility from February 1, 2003 to August 31, 2006. Electronic records were queried for demographic information, bacteria recovered, antibiotic therapies and duration, site of osteomyelitis, orthopedic devices, and outcomes. RESULTS There were 110 patients with 139 hospitalizations for osteomyelitis; 94 involved lower extremities, 43 involved upper extremities, and 2 involved the axial skeleton. One hundred three admissions were initial episodes whereas 36 admissions were recurrences. The median age was 27 years; 95% were men. Duration of follow-up ranged from 2 weeks to 36 months. Those patients with orthopedic devices had recurrent infections more frequently (26 vs. 5%, p < 0.01). Bacteria, antibiotics, or infection site were not predictive of recurrence. Acinetobacter spp. (70 vs. 5%, p < 0.01), Klebsiella pneumoniae (18 vs. 5%, p = 0.04), and Pseudomonas aeruginosa (24 vs. 5%, p < 0.01) were more likely to be recovered during original episodes than during recurrences. Gram-positive organisms were more likely during recurrences; Staphylococcus aureus (13 vs. 53%, p < 0.01); methicillin susceptible S. aureus (5 vs. 22%, p < 0.01), methicillin resistant S. aureus (8 vs. 31%, p < 0.01). CONCLUSIONS The microbiology of osteomyelitis in veterans of OIF/OEF differs substantially depending upon whether the infection is new or recurrent. Gram-negative pathogens predominate early, being replaced with staphylococci after treatment, despite nearly universal use of gram- positive therapy.

Bacteria Recovered from Patients Admitted to a Deployed U.S. Military Hospital in Baghdad, Iraq

The predominant bacteria and antimicrobial susceptibilities were surveyed from a deployed, military, tertiary care facility in Baghdad, Iraq, serving U.S. troops, coalition forces, and Iraqis, from August 2003 through July 2004. We included cultures of blood, wounds, sputum, and urine, for a total of 908 cultures; 176 of these were obtained from U.S. troops. The bacteria most commonly isolated from U.S. troops were coagulase-negative staphylococci, accounting for 34% of isolates, Staphylococcus aureus (26%), and streptococcal species (11%). The 732 cultures obtained from the predominantly Iraqi population were Klebsiella pneumoniae (13%), Acinetobacter baumannii (11%), and Pseudomonas aeruginosa (10%); coagulase-negative staphylococci represented 21% of these isolates. These differences in prevalence were all statistically significant, when compared in chi2 analyses (p < 0.05). Antimicrobial susceptibility testing demonstrated broad resistance among the Gram-negative and Gram-positive bacteria.

History of Infections Associated With Combat-Related Injuries

Despite the innumerable variations in war-making throughout the millennia, wounds have always been characterized by devitalized tissue, the presence of foreign bodies, clots, fluid collection, and contamination by microorganisms. Even in the postantibiotic era, infections of these wounds remain a significant contributor to both morbidity and mortality. Shifts in causal organisms and their resistance profiles continue to challenge each new generation of therapeutics. This article reviews the history of war wound infections, with an emphasis on wound microbiology and combat casualty management during US conflicts from World War I through the end of 20th century.

Infections in combat casualties during Operations Iraqi and Enduring Freedom.

BACKGROUND Infections are a common acute and chronic complication of combat-related injuries; however, no systematic attempt to assess infections associated with US combat-related injuries occurring in Iraq and Afghanistan has been conducted. The Joint Theater Trauma Registry (JTTR) has been established to collect injury specific medical data from casualties in Iraq and Afghanistan. METHODS We reviewed the JTTR for the identification of infectious complications (IC) using International Classification of Diseases, 9th Revision (ICD-9) coding during two phases of the wars, before and after the end of the major ground operations in Iraq (19 March-May 31, 2003 and June 1, 2003-December 31, 2006). ICD-9 codes were combined into two categories; anatomic or clinical syndrome and pathogen. An IC was defined as the presence of ICD-9 codes that included both anatomic or clinical syndrome and a pathogen. RESULTS There were 425 patients evaluated in phase I and 684 in phase II with approximately one third having an IC. The most common anatomic or clinical syndrome codes were skin or wound followed by lung, and the most common pathogen code was gram-negative bacteria. The site of injury had varying rates of IC: spine or back (53%), head or neck (44%), torso (43%), and extremity (35%). Injury Severity Score and certain mechanisms of injury (explosive device, bomb, and landmine) were associated with an IC on multivariate analysis (p < 0.01). CONCLUSION Infections are common after combat-related injuries. Although the JTTR can provide general information regarding infections, improved data capture and more specific clinical information is necessary to improve overall combat-related injury infection care.

Recovery of Multidrug-Resistant Bacteria From Combat Personnel Evacuated From Iraq and Afghanistan at a Single Military Treatment Facility

U.S. combat casualties from Iraq and Afghanistan continue to develop infections with multidrug-resistant (MDR) bacteria. This study assesses the infection control database and clinical microbiology antibiograms at a single site from 2005 to 2007, a period when all Operation Iraqi Freedom (OIF)/Operation Enduring Freedom (OEF) casualties admitted to the facility underwent initial isolation and screening for MDR pathogens. During this 3-year period, there were 2,242 OIF/OEF admissions: 560 in 2005, 724 in 2006, and 958 in 2007. The most commonly recovered pathogens from OIF/OEF admission screening cultures were methicillin-resistant Staphylococcus aureus (MRSA), Klebsiella pneumoniae and Acinetobacter. The yearly nosocomial infection rate of these three pathogens among OIF/OEF admissions ranged between 2 and 4%. There were remarkable changes in resistance profiles for Acinetobacter, K. pneumoniae, and S. aureus over time. Despite aggressive infection control procedures, there is continued nosocomial transmission within the facility and increasing antimicrobial resistance in some pathogens. Novel techniques are needed to control the impact of MDR bacteria in medical facilities.

Tetracycline Susceptibility Testing and Resistance Genes in Isolates of Acinetobacter baumannii-Acinetobacter calcoaceticus Complex from a U.S. Military Hospital

ABSTRACT Infections with multidrug-resistant Acinetobacter baumannii-Acinetobacter calcoaceticus complex bacteria complicate the care of U.S. military personnel and civilians worldwide. One hundred thirty-three isolates from 89 patients at our facility during 2006 and 2007 were tested by disk diffusion, Etest, and broth microdilution for susceptibility to tetracycline, doxycycline, minocycline, and tigecycline. Minocycline was the most active in vitro, with 90% of the isolates tested susceptible. Susceptibilities varied significantly with the testing method. The acquired tetracycline resistance genes tetA, tetB, and tetA(39) were present in the isolates.

Correlation of American Burn Association sepsis criteria with the presence of bacteremia in burned patients admitted to the intensive care unit.

Severe burn injury is accompanied by a systemic inflammatory response, making traditional indicators of sepsis both insensitive and nonspecific. To address this, the American Burn Association (ABA) published diagnostic criteria in 2007 to standardize the definition of sepsis in these patients. These criteria include temperature (>39°C or <36°C), progressive tachycardia (>110 beats per minute), progressive tachypnea (>25 breaths per minute not ventilated or minute ventilation >12 L/minute ventilated), thrombocytopenia (<100,000/&mgr;l; not applied until 3 days after initial resuscitation), hyperglycemia (untreated plasma glucose >200 mg/dl, >7 units of insulin/hr intravenous drip, or >25% increase in insulin requirements over 24 hours), and feed intolerance >24 hours (abdominal distension, residuals two times the feeding rate, or diarrhea >2500 ml/day). Meeting >3 of these criteria should “trigger” concern for infection. In this initial assessment of the ABA sepsis criteria correlation with infection, the authors evaluated the ABA sepsis criterias correlation with bacteremia because bacteremia is not associated with inherent issues of diagnosis as occurs with pneumonia or soft tissue infections, and blood cultures are typically obtained due to concern for ongoing infections falling within the definition of “septic.” A retrospective electronic records review was performed to evaluate episodes of bacteremia in the United States Army Institute of Research from 2006 through 2007. A total of 196 patients were admitted during the study period who met inclusion criteria. The first positive and negative cultures, if present, from each patient were evaluated. This totaled 101 positive and 181 negative cultures. Temperature, heart rate, insulin resistance, and feed intolerance criteria were significant on univariate analysis. Only heart rate and temperature were found to significantly correlate with bacteremia on multivariate analysis. The receiver operating characteristic curve area for meeting >3 ABA sepsis criteria is 0.638 (95% confidence interval 0.573–0.704; P < .001). Among severe burn patients, the ABA trigger for sepsis did not correlate strongly with bacteremia in this retrospective chart review.

Infection prevention and control in deployed military medical treatment facilities.

Infections have complicated the care of combat casualties throughout history and were at one time considered part of the natural history of combat trauma. Personnel who survived to reach medical care were expected to develop and possibly succumb to infections during their care in military hospitals. Initial care of war wounds continues to focus on rapid surgical care with debridement and irrigation, aimed at preventing local infection and sepsis with bacteria from the environment (e.g., clostridial gangrene) or the casualtys own flora. Over the past 150 years, with the revelation that pathogens can be spread from patient to patient and from healthcare providers to patients (including via unwashed hands of healthcare workers, the hospital environment and fomites), a focus on infection prevention and control aimed at decreasing transmission of pathogens and prevention of these infections has developed. Infections associated with combat-related injuries in the recent operations in Iraq and Afghanistan have predominantly been secondary to multidrug-resistant pathogens, likely acquired within the military healthcare system. These healthcare-associated infections seem to originate throughout the system, from deployed medical treatment facilities through the chain of care outside of the combat zone. Emphasis on infection prevention and control, including hand hygiene, isolation, cohorting, and antibiotic control measures, in deployed medical treatment facilities is essential to reducing these healthcare-associated infections. This review was produced to support the Guidelines for the Prevention of Infections Associated With Combat-Related Injuries: 2011 Update contained in this supplement of Journal of Trauma.

Evaluation of potential environmental contamination sources for the presence of multidrug-resistant bacteria linked to wound infections in combat casualties.

OBJECTIVE To determine whether multidrug-resistant (MDR) gram-negative organisms are present in Afghanistan or Iraq soil samples, contaminate standard deployed hospital or modular operating rooms (ORs), or aerosolize during surgical procedures. DESIGN Active surveillance. SETTING US military hospitals in the United States, Afghanistan, and Iraq. METHODS Soil samples were collected from sites throughout Afghanistan and Iraq and analyzed for presence of MDR bacteria. Environmental sampling of selected newly established modular and deployed OR high-touch surfaces and equipment was performed to determine the presence of bacterial contamination. Gram-negative bacteria aerosolization during OR surgical procedures was determined by microbiological analysis of settle plate growth. RESULTS Subsurface soil sample isolates recovered in Afghanistan and Iraq included various pansusceptible members of Enterobacteriaceae, Vibrio species, Pseudomonas species, Acinetobacter lwoffii, and coagulase-negative Staphylococcus (CNS). OR contamination studies in Afghanistan revealed 1 surface with a Micrococcus luteus. Newly established US-based modular ORs and the colocated fixed-facility ORs revealed no gram-negative bacterial contamination prior to the opening of the modular OR and 5 weeks later. Bacterial aerosolization during surgery in a deployed fixed hospital revealed a mean gram-negative bacteria colony count of 12.8 colony-forming units (CFU)/dm(2)/h (standard deviation [SD], 17.0) during surgeries and 6.5 CFU/dm(2)/h (SD, 7.5; [Formula: see text]) when the OR was not in use. CONCLUSION This study demonstrates no significant gram-negative bacilli colonization of modular and fixed-facility ORs or dirt and no significant aerosolization of these bacilli during surgical procedures. These results lend additional support to the role of nosocomial transmission of MDR pathogens or the colonization of the patient themselves prior to injury.

Minocycline Therapy for Traumatic Wound Infections Caused by the Multidrug-resistant acinetobacter baumannii-acinetobacter calcoaceticus Complex

The Acinetobacter baumannii-Acinetobacter calcoaceticus complex has become an important cause of traumatic wound infections in US Army soldiers injured in Iraq. Treatment options for these infections are limited by the organisms ability to acquire broad antimicrobial resistance. Alternative antimicrobial agents that are safe and well tolerated are needed. Minocycline has activity against Acinetobacter and has been used by some in the treatment of pneumonia caused by this pathogen. We report a case series of 8 patients treated with minocycline for traumatic wound infections caused by the multidrug-resistant A. baumannii-A. calcoaceticus complex. Minocycline therapy led to clinical cure for 7 of these patients. The remaining patient experienced adverse effects from minocycline requiring a change in therapy. Minocycline is an alternative agent that may be an effective therapy for multidrug-resistant A. baumannii-A. calcoaceticus complex.