Bacteriology of War Wounds at the Time of Injury

Transcription

1 MILITARY MEDICINE, 171, 9:826, 2006 Bcteriology of Wr Wounds t the Time of Injury Gurntor: MAJ Clinton K. Murry, MC USA Contributors: MAJ Clinton K. Murry, MC USA*; MAJ Sturt A. Roop, MC USA ; LTC(P) Dune R. Hospenthl, MC USA*; COL Dvid P. Dooley, MC USA*; CPT Kimberly Wenner, MC USA ; MAJ John Hmmock, MC USA ; CPT Neil Tufen, MC USA ; MAJ Emmett Gourdine, MS USA Bcteril contmintion of wr wounds occurs either t the time of injury or during the course of therpy. Chrcteriztion of the bcteri recovered t the time of initil trum could influence the selection of empiric ntimicrobil gents used to prevent infection. In the spring of 2004, U.S. militry csulties who presented to the 31st Combt Support Hospitl in Bghdd, Irq, with cute trumtic injuries resulting in open wounds underwent erobic culture of their wounds to identify the bcteri colonizing the wounds. Forty-nine csulties with 61 seprte wounds were evluted. Wounds were locted predominntly in the upper nd lower extremities nd were primrily from improvised explosive devices or mortrs. Thirty wounds (49%) hd bcteri recovered on culture, with 40 bcteri identified. Eighteen csulties (20 wounds) hd undergone field medicl therpy (irrigtion nd/or ntimicrobil tretment); six of these hd nine bcteril isoltes on culture. Of the 41 wounds from 31 ptients who hd received no previous therpy, 24 grew 31 bcteri. Grm-positive bcteri (93%), mostly skin-commensl bcteri, were the predominnt orgnisms identified. Only three Grm-negtive bcteri were detected, none of which were chrcterized s brodly resistnt to ntimicrobil gents. The only resistnt bcteri recovered were two isoltes of methicillin-resistnt Stphylococcus ureus (MRSA). Our ssessment of wr wound bcterioly soon fter injury revels predominnce of Grmpositive orgnisms of low virulence nd pthogenicity. The presence of MRSA in wounds likely reflects the incresing incidence of community-cquired MRSA bcteri. These dt suggest tht the use of brod-spectrum ntibiotics with efficcy ginst more resistnt, Grm-negtive bcteri, such s Pseudomons eruginos nd Acinetobcter spp., is unnecessry in erly wound mngement. Introduction nfection in wr wounds cused gret morbidity, nd often I deth, in the prentibiotic er. The bcteriologicl fetures of these infections were well recognized, nd the evolution of the types of infections nd ttendnt pthogens ws well described, lthough physicins hd little in their rmmentrium other thn debridement with which to tret the ptient. 1 The rrivl of the ntibiotic er rdiclly chnged the tretment nd prognosis of those wounded in wr. Antibiotics begn to be used soon fter *Deprtment of Medicine, Infectious Disese Service, Brooke Army Medicl Center, Fort Sm Houston, TX Deprtment of Medicine, Pulmonry nd Criticl Cre Service, Willim Beumont Army Medicl Center, Fort Bliss, TX st Combt Support Hospitl, Bghdd, Irq. The opinions nd ssertions contined herein re the privte views of the uthors nd re not to be construed s officil or reflecting the views of the Deprtment of Defense or the U.S. government. This work ws prepred s prt of the uthors officil duties; therefore, there is no copyright to be trnsferred. This mnuscript ws received for review in My The revised mnuscript ws ccepted for publiction in November wounding, with the gol of preventing the ppernce of infection in the wound. Surprisingly, only one study hs chrcterized the spectrum of bcteri tht contminte the wound immeditely fter injury (which, if left untreted, would presumbly be the orgnisms to cuse lter wound infections). Tht study evluted cultures collected within few hours fter injury during the Vietnm Wr, reveling mixture of bcteri, mny presumbly nonpthogenic, in the wounds. 2 We hypothesized tht not only susceptible bcteri of less virulence but lso occsionlly resistnt nd pthogenic bcteri would be found to contminte wounds immeditely fter wounding. In this study, we chrcterize the bcteriologicl fetures of wr wounds ner the time of injury during the current Irq conflict. These dt my potentilly shpe the empiric choice of ntimicrobil gents to dequtely control contmintion nd to prevent future infection. Methods Ptient Popultion During the spring of 2004, U.S. militry csulties who rrived t the 31st Combt Support Hospitl (CSH) in Bghdd, Irq, with n cute trumtic injury resulting in n open wound were evluted for the presence of bcteri in their wounds. The 31st CSH ws referrl hospitl for trum throughout Irq. Most csulties (n 31) were directly trnsported by helicopter from the point of injury to the hospitl, rriving within 20 to 40 minutes fter injury. A minority of csulties (n 18) were ir-evcuted to the CSH fter stbiliztion by forwrd deployed physicins, who occsionlly irrigted nd dressed the wounds, infused ntimicrobil gents, or both. Dt collected for ech csulty included mechnism of injury, previous field medicl cre (including wound mngement), ntimicrobil use, nd loction of injury. All mjor wounds of ech csulty were cultured. A minority of ptients who rrived did not undergo seril culturing becuse of mss csulty situtions in which n unstble medicl condition, requiring rpid resuscittion, precluded dequte smpling. The wounding ptterns nd previous tretments of these ptients were similr to those of ptients who underwent culturing when resources were dequte. Culture Technique Two culture swbs (BBL CultureSwb Plus collection nd trnsport system for erobes nd nerobes; Becton Dickinson, Sprks, Mrylnd) were inserted into the wounds during stbiliztion in the emergency deprtment nd were then directly trnsported to the lbortory. Swbs were plted onto Columbi blood gr pltes, chocolte gr pltes, nd McConkey gr pltes nd into thioglycolte broth for the detection of erobic bcteri. Blood gr pltes nd McConkey gr pltes were 826

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3 Bcteriology of Wr Wounds incubted t 35 C in mbient ir nd chocolte gr pltes in the presence of 5 to 10% CO 2. The thioglycolte broth ws Grmstined if it becme turbid. Cultures were held for up to 5 dys before results were clssified s negtive. Results Forty-nine csulties with 61 seprte wounds were evluted. Wound sites cultured included 23 hed nd neck, 17 lower extremity, 15 upper extremity, 5 chest or bck, nd 1 bdomen. Wounds were cused by gunshots for three csulties (five wound smples), improvised explosive devices for 26 csulties (29 wound smples), mortrs for 14 csulties (21 wound smples), nd other mechnisms (e.g., rocket-propelled grende) for six csulties (six wound smples). Tbles I nd II chrcterize wound loctions nd mechnisms of injury for those with nd without field therpy, respectively. Thirty wounds (49%) hd the presence of bcteri in cultures tken t the time of initil presenttion to the CSH (Tbles I nd II). Forty different bcteri were identified (Tble III). Two orgnisms were detected in 10 smples nd one orgnism only ws found in the remining 20 smples. Grm-positive orgnisms (93%) were the predominnt orgnisms identified, with only three Grm-negtive bcteri detected. The predominnt Grmpositive orgnisms were overwhelmingly skin-commensl orgnisms. Two of the Stphylococcus ureus isoltes were methicillin-resistnt S. ureus (MRSA). Conspicuously bsent were streptococci (especilly Streptococcus pyogenes). The three Grm-negtive bcteri identified were not multidrug resistnt. Eighteen csulties (20 wound smples) underwent field medicl cre before evcution nd subsequent culture (Tble I). Six wounds hd the presence of bcteri fter field therpy (Tble I). Of the wounds treted only with field irrigtion (six wounds), none hd positive cultures. Wounds treted only with ntimicrobil gents (eight wounds) hd five positive cultures. Antimicrobil therpy in combintion with irrigtion ws used for six wounds, with one reveling positive culture. Three other wound cultures from ptients who underwent field therpy did not grow bcteri, lthough Grm stins of those cultures reveled Grm-negtive rods in one, Grm-positive diplococci in the second, nd Grm-positive diplococci with Grm-negtive rods in the third. Of the wounds tht did not undergo therpy, 24 hd the presence of bcteri (Tble II). Becuse of rpid evcution out of the CSH, no follow-up dt were vilble to compre our microbiologicl dt with eventul outcomes, especilly the development of wound infections. Discussion 827 Our dt chrcterizing the bcteriologicl fetures of wr wounds immeditely fter injury did not support our hypothesis tht occsionlly resistnt nd pthogenic bcteri would be found to contminte wounds immeditely fter wounding. We found predominnce (93%) of Grm-positive orgnisms, consisting chiefly of skin-commensl pthogens typiclly considered to be of low virulence nd pthogenicity. Resistnt Grm-negtive bcteri such s Pseudomons eruginos, Klebsiell spp., nd Acinetobcter spp. were not recovered. Unique to our dt ws the detection of MRSA s two of the four S. ureus isoltes. Although it ppers beneficil, we were not ble to firmly estblish the impct of forwrd medicl therpy with irrigtion nd/or ntimicrobil gents on the coloniztion rte of wr wounds. The bcteriologicl fetures of wr wounds re often chrcterized by the erly description by Fleming 1 from He reported the evolution of infection in wr wounds through three phses. The first phse consisted of wtery, foul-smelling, reddish brown dischrge ttributed to wound bcteri. Orgnisms typiclly recovered were sporulting nerobes (such s Clostridium spp.) nd streptococci. The second phse occurred 7 dys fter wounding, with trnsition from primrily nerobic infection to infection with nonsporulting bcteri of fecl origin (e.g., Escherichi coli nd Klebsiell spp.). Wounds were chrcterized s more purulent but TABLE I BACTERIAL WOUND CULTURE RESULTS, ACCORDING TO LOCATION AND MECHANISM OF INJURIES FOR PATIENTS WHO HAD UNDERGONE THERAPY IN THE FIELD BEFORE WOUND CULTURING AT THE CSH Antomicl Loction Mechnism of Injury (totl no.) No. Irrigtion Antimicrobils Irrigtion nd Antimicrobils Totl Positive Culture Totl Positive Culture Totl Positive Culture 0 0 Extremity IED (4) 2 0 Cefzolin (2) CNS (1), 2 CNS species (1) Mortr (1) 0 0 Cefzolin (1) CNS (1) 0 0 Other (3) Cefzolin (2), ciprofloxcin (1) 0 Hed nd neck IED (10) 3 0 Ceftrixone (1), cefzolin (2), vncomycin (1) CNS (1) Ceftrixone (1), cefzolin (2) CNS Pseudomons stutzeri (1),b Mortr (1) 0 0 Cefzolin (1) CNS Micrococcus (1),b 0 0 Chest, bck, IED (1) nd bdomen Totl IED, improvised explosive device; CNS, cogulse-negtive Stphylococcus spp. Numbers in prentheses indicte the number of wounds receiving ntimicrobil gents or wounds with corresponding bcteri. Bcteri found with the use of the corresponding ntimicrobil gent. b Both found in the sme wound culture.

4 828 Bcteriology of Wr Wounds TABLE II BACTERIAL WOUND CULTURE RESULTS, ACCORDING TO LOCATION AND MECHANISM OF INJURIES, FOR PATIENTS WHO HAD NOT UNDERGONE THERAPY BEFORE WOUND CULTURING AT THE CSH No. Antomicl Loction Mechnism of Injury Totl Positive Culture Extremity Gunshot 2 0 IED 9 3 CNS, 1 MRSA Mortr 12 7 CNS, 1 Stphylococcus ureus, 2 CNS CNS Other 1 1 MRSA Chryseobcterium meningosepticum Hed nd neck Gunshot 2 1 CNS IED 4 1 CNS CNS, 1 S. ureus Escherichi coli Mortr 4 1 CNS, 1 CNS CNS Other 2 1 CNS, 1 CNS CNS Chest, bck, nd bdomen Gunshot 1 1 CNS IED 1 0 Mortr 3 1 CNS Totl IED, improvised explosive device; CNS, cogulse-negtive Stphylococcus spp.; MRSA, methicillin-resistnt S. ureus. Numbers preceding bcteri indicte the number of cultures with corresponding bcteri. Both found in the sme wound culture. TABLE III BACTERIA CULTURED IN WAR WOUNDS FROM 49 CASUALTIES (61 WOUNDS) Grm-Positive Bcteri No. Grm-Negtive Bcteri No. Cogulse-negtive Stphylococcus 32 Pseudomons stutzeri 1 Stphylococcus epidermidis 12 Chryseobcterium meningosepticum 1 Stphylococcus uriculris 10 Escherichi coli 1 Stphylococcus hominis hominis 6 Stphylococcus wrneri 2 Stphylococcus cohnii cohnii 1 Stphylococcus sprophyticus 1 Stphylococcus ureus 4 Micrococcus sp. 1 Two isoltes were MRSA. such dringe then diminished progressively over 2 to 3 weeks. The third phse ws prolonged period with persistent prolifertion of pyogenic orgnisms nd resolution of fecl orgnisms. Representtive bcteri in this third phse included Stphylococcus spp. nd S. pyogenes. Modern surgicl mngement of wounds, focusing on ggressive debridement, likely led to the essentil disppernce of clostridil gs gngrene between World Wr I nd the Koren Wr. Implementtion of penicillin use fter wounding during World Wr II probbly led to the diminution of S. pyogenes infection, becuse this species remins universlly susceptible to this gent. The more recent expnded use nd broder spectr of ntimicrobil gents occurred simultneously with the ppernce of incresingly resistnt bcteri in wr wounds. 3,4 These orgnisms include multidrug-resistnt P. eruginos, extended-spectrum -lctmse-producing Klebsiell spp., nd Acinetobcter spp., ll of which hve ppered in wr wounds incurred during Opertion Irqi Freedom nd Opertion Enduring Freedom. 5 These bcteri pper to colonize wounds during definitive cre in hospitls. Erly wound culture dt re limited to one study performed by Tong, 2 describing the bcteri cultured from 63 wounds of 30 injured U.S. Mrines in Vietnm. Csulties presented within 2.5 hours fter injury, with cultures being obtined before initition of debridement or ntimicrobil tretment. Initil culture results reveled reltively even mixture of Grm-negtive nd Grm-positive bcteri, with predominnce of Stphylococcus epidermidis, Bcillus subtilis, Mimee-Herelle-Bcterium-Alcligenes (likely the orgnism now known s Acinetobcter), nd Enterobcter group. Cultures obtined 5 dys fter surgicl therpy nd implementtion of ntimicrobil tretment (typiclly penicillin with streptomycin sulfte, chlormphenicol sodium succinte, or colistin) reveled tht 84% of wounds grew Grm-negtive bcteri. S. epidermidis decresed from 24% of bcteril isoltes on dy 1 to 5% of isoltes on dy 5. In contrst, P. eruginos incresed from 2% of bcteril isoltes to 29% of isoltes between dys 1 nd 5. Bcteril contmintion of wr wounds occurs either t the time of injury or secondry to contmintion during the course of therpy. 6 The utility of ntimicrobil gents in the mnge-

5 Bcteriology of Wr Wounds ment of wr wounds soon fter n injury is supported by niml nd humn studies, especilly if debridement is delyed. 7,8 However, ntibiotics my influence wound flor, selecting more resistnt bcteri, risk tht remins unproven. 4 One current controversy tht is yet unresolved is the identifiction of the idel ntibiotic(s) for use in wr wound prophylxis. Rndomized prospective studies ssessing vrious tretment strtegies would be the idel mens to determine the role of ntimicrobil gents in csulty wound prophylxis. Questions to be ddressed would include whether therpy should be nrrow or brod in spectrum of ctivity nd how long therpy should continue, or even whether such prophylctic ntimicrobil therpy is clerly beneficil t ll. Given the circumstnces surrounding the cre of wr wounds, controlled studies hve not occurred nd re unlikely to be performed in the future. Antimicrobil gents tht were proposed for tcticl combt csulty cre by one U.S. Specil Opertions group include gtifloxcin for ptients with extremity wounds nd cefotetn for ptients with bdominl injuries, unconscious ptients, nd ptients in shock. 9 The Interntionl Committee of the Red Cross hs recommended penicillin for compound frctures, mputtions, or mjor soft tissue wounds. 10 If the injury is ssocited with lnd mines or therpy is delyed for 72 hours, then penicillin used in combintion with metronidzole is suggested. Our dt support potentil need for dequte Grm-positive coverge in cute wounds but do not suggest tht broder coverge ginst resistnt Grm-negtive bcteri needs to be provided immeditely fter wounding. The only resistnt bcteri we noted were rre MRSA isoltes. The presence of wr wound MRSA is not unexpected, given the incresing prevlence of community-cquired MRSA, which is known skin colonizer nd thus is likely introduced into wounds t the time of trum. 11 Approximtely 4% of wounded soldiers hd MRSA in wound cultures, which pproximtes the 3% coloniztion rte described mong ctive duty soldiers. 11 Our dt do not suggest tht the Grm-negtive bcilli recognized in wounds during recent conflicts (Vietnm, Somli, nd Irq) re inoculted t the time of injury. 2,5,12 Insted, it is more probble tht these orgnisms gin ccess to open wounds through contct with medicl cre, through mechnisms similr to those seen in civilin institutions. This study hs limittions. The dt re limited by potentil smpling bis ttributble to the dmittedly limited number of csulties nd wounds ssessed. In ddition, the use of culture swbs might not hve detected ll of the bcteri in the wounds s thoroughly s tissue smples would. However, given the size of the wounds, rndom smll tissue smples lso might hve missed the presence of bcteri. Anerobic cultures were not obtined, but nerobic bcteri hve been uncommonly recognized s cuse of wr wound infections since rpid evcution nd debridement hve become norml prctice (pproximtely since the Koren Wr). In ddition, these smples were obtined in one re of the world nd my not represent other regions with different ecosystems nd bcteri. An dditionl limittion ws the inbility to stndrdize tretment protocols before wound culture. Finlly, becuse this ws not longitudinl study, we were unble to chrcterize the development of infection lter in these csulties courses. However, the bcteri initilly colonizing wounds t the time of injury re the probble (t lest the first) orgnisms tht should be erdicted by erly wound mngement, to prevent the lter development of infection. In summry, wr wound cultures obtined immeditely fter injury during the current Irq conflict showed the presence of rnge of less pthogenic, Grm-positive, skin-commensl bcteri. Grm-negtive bcteri were rrely found in wounds t the time of initil injury, nd none ws multidrug resistnt. Similrly, MRSA ws uncommonly found in wounds. These dt emphsize the need for effective infection-control prctices, to prevent nosocomil trnsmission of resistnt bcteri such s P. eruginos, Klebsiell pneumoni, nd Acinetobcter spp. into wounds. These dt lso suggest tht the use of brod-spectrum ntibiotics is unnecessry in erly wound mngement, if indeed coloniztion (with possible subsequent infection) with resistnt orgnisms does not occur until fter contct with medicl cre. References Fleming A: The ction of chemicl nd physiologicl ntiseptics in septic wound. Br J Surg 1919; 7: Tong MJ: Septic complictions of wr wounds. JAMA 1972; 219: Kovric JJ, Mtsumoto T, Dobek AS, Hmit HF: Bcteril flor of one hundred nd twelve combt wounds. Milit Med 1968; 133: Klein RS, Berger SA, Yekutiel P: Wound infection during the Yom Kippur Wr: observtions concerning ntibiotic prophylxis nd therpy. Ann Surg 1975; 182: Centers for Disese Control nd Prevention: Acinetobcter bumnnii infections mong ptients t militry medicl fcilities treting injured U.S. service members, MMWR 2004; 53: Bowen TE, Bellmy RF: Emergency Wr Surgery, Ed 2. Wshington, DC, U.S. Government Printing Office, Mellor SG, Cooper GJ, Bowyer GW: Efficcy of delyed dministrtion of benzylpenicillin in the control of infection in penetrting soft tissue injuries in wr. J Trum 1996; 40(Suppl): S Jckson DS: Sepsis in soft tissue limb wounds in soldiers injured during the Flklnds cmpign, J R Army Med Corps 1984; 130: Butler F, O Connor K: Antibiotics in tcticl combt csulty cre, Milit Med 2003; 168: Betrncourt B, Dufour D, Jensen SK, Owen-Smith M, et l: Infections in wr wounds, Chp 8, pp In: Surgery for Victims of Wr. Edited by Moulde A. Genev, Switzerlnd, Interntionl Committee of the Red Cross, Ellis MW, Hospenthl DR, Dooley DP, Gry PJ, Murry CK: Nturl history of community-cquired methicillin-resistnt Stphylococcus ureus coloniztion nd infection in soldiers. Clin Infect Dis 2004; 39: Mbry RL, Holcomb JB, Bker AM, et l: United Sttes Army Rngers in Somli: n nlysis of combt csulties on n urbn bttlefield. J Trum 2000; 49: