RESUMO
Soft-tissue invasive fungal infections are increasingly recognized as significant entities directly contributing to morbidity and mortality. They complicate clinical care, requiring aggressive surgical debridement and systemic antifungal therapy. To evaluate new topical approaches to therapy, we examined the antifungal activity and cytotoxicity of Manuka Honey (MH) and polyhexamethylene biguanide (PHMB). The activities of multiple concentrations of MH (40%, 60%, 80%) and PHMB (0.01%, 0.04%, 0.1%) against 13 clinical mould isolates were evaluated using a time-kill assay between 5 min and 24 h. Concentrations were selected to represent current clinical use. Cell viability was examined in parallel for human epidermal keratinocytes, dermal fibroblasts and osteoblasts, allowing determination of the 50% viability (LD50) concentration. Antifungal activity of both agents correlated more closely with exposure time than concentration. Exophiala and Fusarium growth was completely suppressed at 5 min for all PHMB concentrations, and at 12 and 6 h, respectively, for all MH concentrations. Only Lichtheimia had persistent growth to both agents at 24 h. Viability assays displayed concentration-and time-dependent toxicity for PHMB. For MH, exposure time predicted cytotoxicity only when all cell types were analyzed in aggregate. This study demonstrates that MH and PHMB possess primarily time-dependent antifungal activity, but also exert in vitro toxicity on human cells which may limit clinical use. Further research is needed to determine ideal treatment strategies to optimize antifungal activity against moulds while limiting cytotoxicity against host tissues in vivo.
Assuntos
Biguanidas/farmacologia , Desinfetantes/farmacologia , Fibroblastos/efeitos dos fármacos , Fungos/efeitos dos fármacos , Mel , Queratinócitos/efeitos dos fármacos , Osteoblastos/efeitos dos fármacos , Biguanidas/toxicidade , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Desinfetantes/toxicidade , Fibroblastos/fisiologia , Fungos/fisiologia , Humanos , Queratinócitos/fisiologia , Dose Letal Mediana , Testes de Sensibilidade Microbiana , Osteoblastos/fisiologia , Fatores de TempoRESUMO
BACKGROUND: The role of microbial colonization in disease is complex. Novel molecular tools to detect colonization offer theoretical improvements over traditional methods. We evaluated PCR/Electrospray Ionization-Time-of-Flight-Mass Spectrometry (PCR/ESI-TOF-MS) as a screening tool to study colonization of healthy military service members. METHODS: We assessed 101 healthy Soldiers using PCR/ESI-TOF-MS on nares, oropharynx, and groin specimens for the presence of gram-positive and gram-negative bacteria (GNB), fungi, and antibiotic resistance genes. A second set of swabs was processed by traditional culture, followed by identification using the BD Phoenix automated system; comparison between PCR/ESI-TOF-MS and culture was carried out only for GNB. RESULTS: Using PCR/ESI-TOF-MS, at least one colonizing organism was found on each individual: mean (SD) number of organisms per subject of 11.8(2.8). The mean number of organisms in the nares, groin and oropharynx was 3.8(1.3), 3.8(1.4) and 4.2(2), respectively. The most commonly detected organisms were aerobic gram-positive bacteria: primarily coagulase-negative Staphylococcus (101 subjects: 341 organisms), Streptococcus pneumoniae (54 subjects: 57 organisms), Staphylococcus aureus (58 subjects: 80 organisms) and Nocardia asteroides (45 subjects: 50 organisms). The mecA gene was found in 96 subjects. The most commonly found GNB was Haemophilus influenzae (20 subjects: 21 organisms) and the most common anaerobe was Propionibacterium acnes (59 subjects). Saccharomyces species (30 subjects) were the most common fungi detected. Only one GNB (nares E. coli) was identified in the same subject by both diagnostic systems. CONCLUSION: PCR/ESI-TOF-MS detected common colonizing organisms and identified more typically-virulent bacteria in asymptomatic, healthy adults. PCR/ESI-TOF-MS appears to be a useful method for detecting bacterial and fungal organisms, but further clinical correlation and validation studies are needed.
Assuntos
Bactérias/isolamento & purificação , Fungos/isolamento & purificação , Microbiota , Militares , Reação em Cadeia da Polimerase/métodos , Espectrometria de Massas por Ionização por Electrospray , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Adulto , Bactérias/genética , Bactérias/crescimento & desenvolvimento , Escherichia coli/genética , Escherichia coli/crescimento & desenvolvimento , Escherichia coli/isolamento & purificação , Feminino , Fungos/genética , Fungos/crescimento & desenvolvimento , Bactérias Gram-Negativas/genética , Bactérias Gram-Negativas/crescimento & desenvolvimento , Bactérias Gram-Negativas/isolamento & purificação , Saúde , Humanos , Masculino , Técnicas Microbiológicas/métodos , Técnicas de Diagnóstico Molecular/métodos , Projetos Piloto , Staphylococcus aureus/genética , Staphylococcus aureus/crescimento & desenvolvimento , Staphylococcus aureus/isolamento & purificação , Adulto JovemRESUMO
Invasive fungal wound infections (IFIs) are increasingly reported in trauma patients and cause considerable morbidity and mortality despite standard of care treatment in trauma centers by experienced medical personnel. Topical agents such as oil of melaleuca, also known as tea tree oil (TTO), have been proposed for adjunctive treatment of IFIs. We evaluated the activity of TTO against filamentous fungi associated with IFIs by testing 13 clinical isolates representing nine species via time-kill assay with seven concentrations of TTO (100%, 75%, 50%, 25%, 10%, 5%, and 1%). To ascertain the safety of topical application to wounds, cell viability assays were performed in vitro using human fibroblasts, keratinocytes, osteoblasts, and umbilical vein endothelial cells with 10 concentrations of TTO (75%, 50%, 25%, 10%, 5%, and 10-fold serial dilutions from 1 to 0.0001%) at five time points (5, 15, 30, 60, and 180 min). Compatibility of TTO with explanted porcine tissues was also assessed with eight concentrations of TTO (100%, 75%, 50%, 25%, 10%, 5%, 1%, and 0.1%) at the time points used for cellular assays and at 24 h. The time-kill studies showed that fungicidal activity was variable between isolates. The effect of TTO on cell viability was primarily concentration dependent with significant cytotoxicity at concentrations of ≥ 10% and ≥ 50% for cells lines and whole tissue, respectively. Our findings demonstrate that TTO possesses antifungal activity against filamentous fungi associated with IFIs; furthermore that negligible effects on whole tissues, in contrast to individual cells, were observed following exposure to TTO. Collectively, these findings indicate a potential use of TTO as topical treatment of IFIs.
Assuntos
Antifúngicos/farmacologia , Antifúngicos/toxicidade , Fungos/efeitos dos fármacos , Melaleuca/química , Óleo de Melaleuca/farmacologia , Óleo de Melaleuca/toxicidade , Animais , Antifúngicos/isolamento & purificação , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Células Endoteliais/efeitos dos fármacos , Fibroblastos/efeitos dos fármacos , Fungos/isolamento & purificação , Humanos , Queratinócitos/efeitos dos fármacos , Micoses/microbiologia , Osteoblastos/efeitos dos fármacos , Suínos , Óleo de Melaleuca/isolamento & purificação , Infecção dos Ferimentos/microbiologiaRESUMO
BACKGROUND: Biofilms are associated with persistent infection. Reports characterizing clinical infectious outcomes and patient risk factors for colonization or infection with biofilm forming isolates are scarce. Our institution recently published a study examining the biofilm forming ability of 205 randomly selected clinical isolates. This present study aims to identify potential risk factors associated with these isolates and assess clinical infectious outcomes. METHODS: 221 clinical isolates collected from 2005 to 2012 and previously characterized for biofilm formation were studied. Clinical information from the associated patients, including demographics, comorbidities, antibiotic usage, laboratory values, and clinical infectious outcomes, was determined retrospectively through chart review. Duplicate isolates and non-clinical isolates were excluded from analysis. Associations with biofilm forming isolates were determined by univariate analysis and multivariate analysis. RESULTS: 187 isolates in 144 patients were identified for analysis; 113 were biofilm producers and 74 were not biofilm producers. Patients were primarily male (78 %) military members (61 %) with combat trauma (52 %). On multivariate analysis, the presence of methicillin-resistant Staphylococcus aureus (p < 0.01, OR 5.09, 95 % CI 1.12, 23.1) and Pseudomonas aeruginosa (p = 0.02, OR 3.73, 95 % CI 1.46, 9.53) were the only characteristics more likely to be present in the biofilm producing isolate group. Infectious outcomes of patients with non-biofilm forming isolates, including cure, relapse/reinfection, and chronic infection, were similar to infectious outcomes of patients with biofilm-forming isolates. Mortality with initial infection was higher in the biofilm producing isolate group (16 % vs 5 %, p = 0.01) but attributable mortality was low (1 of 14). No characteristics examined in this study were found to be associated with relapse/reinfection or chronic infection on multivariate analysis. CONCLUSIONS: Bacteria species, but not clinical characteristics, were associated with biofilm formation on multivariate analysis. Biofilm forming isolates and non-biofilm forming isolates had similar infectious outcomes in this study.
Assuntos
Infecções Bacterianas/patologia , Biofilmes/crescimento & desenvolvimento , Staphylococcus aureus Resistente à Meticilina/fisiologia , Pseudomonas aeruginosa/fisiologia , Adulto , Infecções Bacterianas/microbiologia , Demografia , Feminino , Humanos , Masculino , Staphylococcus aureus Resistente à Meticilina/isolamento & purificação , Pessoa de Meia-Idade , Análise Multivariada , Pseudomonas aeruginosa/isolamento & purificação , Recidiva , Estudos Retrospectivos , Fatores de RiscoRESUMO
Escherichia coli is the most common colonizing and infecting organism isolated from U.S. service members injured during deployment. Our objective was to evaluate the phenotypic and genotypic changes of infecting and colonizing E. coli organisms over time and across facilities to better understand their transmission patterns. E. coli isolates were collected via surveillance cultures and infection workups from U.S. military personnel injured during deployment (June 2009 to May 2011). The isolates underwent antimicrobial susceptibility testing, pulsed-field gel electrophoresis, and multiplex PCR for phylotyping to determine their resistance profiles and clonality. A total of 343 colonizing and 136 infecting E. coli isolates were analyzed, of which 197 (57%) and 109 (80%) isolates, respectively, produced extended-spectrum ß-lactamases (ESBL). Phylogroup A was predominant among both colonizing (38%) and infecting isolates (43%). Although 188 unique pulsed-field types (PFTs) were identified from the colonizing isolates, and 54 PFTs were identified from the infecting isolates, there was a lack of PFT overlap between study years, combat zones, and military treatment facilities. On a per-subject basis, 26% and 32% of the patients with serial colonizing isolates and 10% and 21% with serial infecting isolates acquired changes in their phylogroup and PFT profiles, respectively, over time. The production of ESBL remained high over time and across facilities, with no substantial changes in antimicrobial susceptibilities. Overall, our results demonstrated an array of genotypic and phenotypic differences for the isolates without large clonal clusters; however, the same PFTs were occasionally observed in the colonizing and infecting isolates, suggesting that the source of infections may be endogenous host organisms.
Assuntos
Portador Sadio/microbiologia , Infecções por Escherichia coli/microbiologia , Escherichia coli/classificação , Escherichia coli/isolamento & purificação , Militares , Adulto , Portador Sadio/epidemiologia , Análise por Conglomerados , Estudos de Coortes , Eletroforese em Gel de Campo Pulsado , Escherichia coli/genética , Escherichia coli/fisiologia , Infecções por Escherichia coli/epidemiologia , Feminino , Genótipo , Humanos , Masculino , Testes de Sensibilidade Microbiana , Tipagem Molecular , Fenótipo , Reação em Cadeia da Polimerase , Fatores de Tempo , Adulto JovemRESUMO
BACKGROUND: Complex traumatic injuries sustained by military personnel, particularly when involving extremities, often result in infectious complications and substantial morbidity. One factor that may further impair patient recovery is the persistence of infections. Surface-attached microbial communities, known as biofilms, may play a role in hindering the management of infections; however, clinical data associating biofilm formation with persistent or chronic infections are lacking. Therefore, we evaluated the production of bacterial biofilms as a potential risk factor for persistent infections among wounded military personnel. METHODS: Bacterial isolates and clinical data from military personnel with deployment-related injuries were collected through the Trauma Infectious Disease Outcomes Study. The study population consisted of patients with diagnosed skin and soft-tissue infections. Cases (wounds with bacterial isolates of the same organism collected 14 days apart) were compared to controls (wounds with non-recurrent bacterial isolates), which were matched by organism and infectious disease syndrome. Potential risk factors for persistent infections, including biofilm formation, were examined in a univariate analysis. Data are expressed as odds ratios (OR; 95% confidence interval [CI]). RESULTS: On a per infected wound basis, 35 cases (representing 25 patients) and 69 controls (representing 60 patients) were identified. Eight patients with multiple wounds were utilized as both cases and controls. Overall, 235 bacterial isolates were tested for biofilm formation in the case-control analysis. Biofilm formation was significantly associated with infection persistence (OR: 29.49; CI: 6.24-infinity) in a univariate analysis. Multidrug resistance (OR: 5.62; CI: 1.02-56.92), packed red blood cell transfusion requirements within the first 24 hours (OR: 1.02; CI: 1.01-1.04), operating room visits prior to and on the date of infection diagnosis (OR: 2.05; CI: 1.09-4.28), anatomical location of infected wound (OR: 5.47; CI: 1.65-23.39), and occurrence of polymicrobial infections (OR: 69.71; CI: 15.39-infinity) were also significant risk factors for persistent infections. CONCLUSIONS: We found that biofilm production by clinical strains is significantly associated with the persistence of wound infections. However, the statistical power of the analysis was limited due to the small sample size, precluding a multivariate analysis. Further data are needed to confirm biofilm formation as a risk factor for persistent wound infections.
Assuntos
Biofilmes , Militares/estatística & dados numéricos , Infecção dos Ferimentos/epidemiologia , Infecção dos Ferimentos/microbiologia , Adulto , Estudos de Casos e Controles , Doença Crônica , Feminino , Humanos , Masculino , Fatores de Risco , Estados Unidos/epidemiologia , Ferimentos e Lesões/microbiologia , Adulto JovemRESUMO
BACKGROUND: Biofilm formation is a major virulence factor contributing to the chronicity of infections. To date few studies have evaluated biofilm formation in infecting isolates of patients including both Gram-positive and Gram-negative multidrug-resistant (MDR) species in the context of numerous types of infectious syndromes. Herein, we investigated the biofilm forming capacity in a large collection of single patient infecting isolates and compared the relationship between biofilm formation to various strain characteristics. METHODS: The biofilm-forming capacity of 205 randomly sampled clinical isolates from patients, collected from various anatomical sites, admitted for treatment at Brooke Army Medical Center (BAMC) from 2004-2011, including methicillin-resistant/methicillin susceptible Staphylococcus aureus (MRSA/MSSA) (n=23), Acinetobacter baumannii (n=53), Pseudomonas aeruginosa (n=36), Klebsiella pneumoniae (n=54), and Escherichia coli (n=39), were evaluated for biofilm formation using the high-throughput microtiter plate assay and scanning electron microscopy (SEM). Relationships between biofilm formation to clonal type, site of isolate collection, and MDR phenotype were evaluated. Furthermore, in patients with relapsing infections, serial strains were assessed for their ability to form biofilms in vitro. RESULTS: Of the 205 clinical isolates tested, 126 strains (61.4%) were observed to form biofilms in vitro at levels greater than or equal to the Staphylococcus epidermidis, positive biofilm producing strain, with P. aeruginosa and S. aureus having the greatest number of biofilm producing strains. Biofilm formation was significantly associated with specific clonal types, the site of isolate collection, and strains positive for biofilm formation were more frequently observed to be MDR. In patients with relapsing infections, the majority of serial isolates recovered from these individuals were observed to be strong biofilm producers in vitro. CONCLUSIONS: This study is the first to evaluate biofilm formation in a large collection of infecting clinical isolates representing diverse types of infections. Our results demonstrate: (1) biofilm formation is a heterogeneous property amongst clinical strains which is associated with certain clonal types, (2) biofilm forming strains are more frequently isolated from non-fluid tissues, in particular bone and soft tissues, (3) MDR pathogens are more often biofilm formers, and (4) strains from patients with persistent infections are positive for biofilm formation.
Assuntos
Infecções Bacterianas/microbiologia , Biofilmes , Bactérias Gram-Negativas/fisiologia , Bactérias Gram-Positivas/fisiologia , Antibacterianos/farmacologia , Doença Crônica , Farmacorresistência Bacteriana , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Negativas/isolamento & purificação , Bactérias Gram-Positivas/efeitos dos fármacos , Bactérias Gram-Positivas/isolamento & purificação , Humanos , RecidivaRESUMO
BACKGROUND: Staphylococcus aureus [methicillin-resistant and methicillin-susceptible (MRSA/MSSA)] is a leading cause of infections in military personnel, but there are limited data regarding baseline colonization of individuals while deployed. We conducted a pilot study to screen non-deployed and deployed healthy military service members for MRSA/MSSA colonization at various anatomic sites and assessed isolates for molecular differences. METHODS: Colonization point-prevalence of 101 military personnel in the US and 100 in Afghanistan was determined by swabbing 7 anatomic sites. US-based individuals had received no antibiotics within 30 days, and Afghanistan-deployed personnel were taking doxycycline for malaria prophylaxis. Isolates underwent identification and testing for antimicrobial resistance, virulence factors, and pulsed-field type (PFT). RESULTS: 4 individuals in the US (4 isolates- 3 oropharynx, 1 perirectal) and 4 in Afghanistan (6 isolates- 2 oropharynx, 2 nare, 1 hand, 1 foot) were colonized with MRSA. Among US-based personnel, 3 had USA300 (1 PVL+) and 1 USA700. Among Afghanistan-based personnel, 1 had USA300 (PVL+), 1 USA800 and 2 USA1000. MSSA was present in 40 (71 isolates-25 oropharynx, 15 nare) of the US-based and 32 (65 isolates- 16 oropharynx, 24 nare) of the Afghanistan-based individuals. 56 (79%) US and 41(63%) Afghanistan-based individuals had MSSA isolates recovered from extra-nare sites. The most common MSSA PFTs were USA200 (9 isolates) in the US and USA800 (7 isolates) in Afghanistan. MRSA/MSSA isolates were susceptible to doxycycline in all but 3 personnel (1 US, 2 Afghanistan; all were MSSA isolates that carried tetM). CONCLUSION: MRSA and MSSA colonization of military personnel was not associated with deployment status or doxycycline exposure. Higher S. aureus oropharynx colonization rates were observed and may warrant changes in decolonization practices.
Assuntos
Militares , Staphylococcus aureus/isolamento & purificação , Adulto , Afeganistão , Farmacorresistência Bacteriana , Feminino , Humanos , Masculino , Staphylococcus aureus/classificação , Staphylococcus aureus/efeitos dos fármacos , Estados Unidos , Fatores de Virulência/metabolismoRESUMO
BACKGROUND: The US military has seen steady increases in multidrug-resistant (MDR) gram-negative bacteria (GNB) infections in casualties from Iraq and Afghanistan. This study evaluates the prevalence of MDR GNB colonization in US military personnel. METHODS: GNB colonization surveillance of healthy, asymptomatic military personnel (101 in the US and 100 in Afghanistan) was performed by swabbing 7 anatomical sites. US-based personnel had received no antibiotics within 30 days of specimen collection, and Afghanistan-based personnel were receiving doxycycline for malaria chemoprophylaxis at time of specimen collection. Isolates underwent genotypic and phenotypic characterization. RESULTS: The only colonizing MDR GNB recovered in both populations was Escherichia coli (p=0.01), which was seen in 2% of US-based personnel (all perirectal) and 11% of Afghanistan-based personnel (10 perirectal, 1 foot+groin). Individuals with higher off-base exposures in Afghanistan did not show a difference in overall GNB colonization or MDR E. coli colonization, compared with those with limited off-base exposures. CONCLUSION: Healthy US- and Afghanistan-based military personnel have community onset-MDR E. coli colonization, with Afghanistan-based personnel showing a 5.5-fold higher prevalence. The association of doxycycline prophylaxis or other exposures with antimicrobial resistance and increased rates of MDR E. coli colonization needs further evaluation.
Assuntos
Antibacterianos/farmacologia , Portador Sadio/epidemiologia , Farmacorresistência Bacteriana Múltipla , Infecções por Escherichia coli/epidemiologia , Escherichia coli/efeitos dos fármacos , Militares , Adulto , Afeganistão/epidemiologia , Portador Sadio/microbiologia , Escherichia coli/isolamento & purificação , Infecções por Escherichia coli/microbiologia , Feminino , Humanos , Masculino , Prevalência , Estados Unidos/epidemiologia , Adulto JovemRESUMO
BACKGROUND: Acinetobacter baumannii-calcoaceticus complex (ABC) isolates are often multidrug-resistant, including to carbapenems. Chromogenic media can facilitate the rapid detection of Gram-negative bacteria, often with the addition of supplements to a base chromogenic medium to detect resistance. We examined various combinations of available media to detect imipenem resistance among 107 ABC clinical isolates. METHODS: CHROMagar Orientation, CHROMagar KPC, and CHROMagar Acinetobacter, by itself, with Acinetobacter supplement, with KPC supplement, or CHROMagar Acinetobacter with increasing concentrations (1, 2.5, and 5 ml/l) of a new CR102 supplement, were examined. RESULTS: Sensitivity for the detection of isolates was high (> 98%) for all formulations. Specificity was high for CHROMagar Acinetobacter with 2.5 ml/l and 5 ml/l of the CR102 supplement, at 95.3% and 97.7%, respectively, with positive predictive values of 97% and 98.5%. Negative predictive values of these 2 formulations were 100%. CONCLUSIONS: CHROMagar Acinetobacter with the addition of the CR102 supplement at 2.5 ml/l and 5ml/l is highly sensitive and specific for the detection of imipenem-resistant ABC, and may be useful for the rapid detection of imipenem-resistant ABC in clinical samples.
Assuntos
Infecções por Acinetobacter/microbiologia , Acinetobacter baumannii/efeitos dos fármacos , Acinetobacter calcoaceticus/efeitos dos fármacos , Antibacterianos/farmacologia , Técnicas de Tipagem Bacteriana/métodos , Imipenem/farmacologia , Acinetobacter baumannii/classificação , Acinetobacter baumannii/isolamento & purificação , Acinetobacter calcoaceticus/classificação , Acinetobacter calcoaceticus/isolamento & purificação , Meios de Cultura , Humanos , Testes de Sensibilidade Microbiana , Valor Preditivo dos Testes , Resistência beta-LactâmicaRESUMO
BACKGROUND: Methicillin-resistant (MRSA) and methicillin-susceptible (MSSA) Staphylococcus aureus colonization is associated with increased rates of infection. Rapid and reliable detection methods are needed to identify colonization of nares and extra-nare sites, particularly given recent reports of oropharynx-only colonization. Detection methods for MRSA/MSSA colonization include culture, PCR, and novel methods such as PCR/electrospray ionization time-of-flight mass spectrometry (ESI-TOF-MS). METHODS: We evaluated 101 healthy military members for S. aureus colonization in the nares, oropharynx, axilla, and groin, using CHROMagar S. aureus medium and Xpert SA Nasal Complete PCR for MRSA/MSSA detection. The same subjects were screened in the nares, oropharynx, and groin using PCR/ESI-TOF-MS. RESULTS: By culture, 3 subjects were MRSA-colonized (all oropharynx) and 34 subjects were MSSA-colonized (all 4 sites). PCR detected oropharyngeal MRSA in 2 subjects, which correlated with culture findings. By PCR, 47 subjects were MSSA-colonized (all 4 sites); however, 43 axillary samples were invalid, 39 of which were associated with deodorant/anti-perspirant use (93%, p < 0.01). By PCR/ESI-TOF-MS, 4 subjects were MRSA-colonized, 2 in the nares and 2 in the oropharynx; however, neither of these correlated with positive MRSA cultures. Twenty-eight subjects had MSSA by PCR/ESI-TOF-MS, and 41 were found to have possible MRSA (S. aureus with mecA and coagulase-negative Staphylococcus (CoNS)). CONCLUSION: The overall 3% MRSA colonization rate is consistent with historical reports, but the oropharynx-only colonization supports more recent findings. In addition, the use of deodorant/anti-perspirant invalidated axillary PCR samples, limiting its utility. Defining MRSA positivity by PCR/ESI-TOF-MS is complicated by co-colonization of S. aureus with CoNS, which can also carry mecA.
Assuntos
Técnicas Bacteriológicas/métodos , Portador Sadio/diagnóstico , Espectrometria de Massas/métodos , Reação em Cadeia da Polimerase/métodos , Infecções Estafilocócicas/diagnóstico , Staphylococcus aureus/isolamento & purificação , Adolescente , Adulto , Portador Sadio/microbiologia , Feminino , Humanos , Masculino , Resistência a Meticilina , Militares , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/química , Staphylococcus aureus/genética , Staphylococcus aureus/crescimento & desenvolvimento , Adulto JovemRESUMO
Epidemiologic evidence suggests a beneficial effect of HMG-CoA reductase inhibitors (statins) in sepsis, and in-vitro data exist for antimicrobial activity of statins against some bacteria and fungi. We examined whether statin exposure at physiologic concentrations enhances activity of selected antimicrobials against Acinetobacter baumannii, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Escherichia coli. Broth microdilution was performed with and without dose-ranging concentrations of lovastatin, fluvastatin, atorvastatin, pravastatin and simvastatin. No effects on antimicrobial activity were demonstrated.
Assuntos
Antibacterianos/farmacologia , Interações Medicamentosas , Bacilos e Cocos Aeróbios Gram-Negativos/efeitos dos fármacos , Inibidores de Hidroximetilglutaril-CoA Redutases/farmacologia , Testes de Sensibilidade MicrobianaRESUMO
Enterobacter cloacae is a Gram-negative rod with multidrug-resistant potential due to chromosomally-induced AmpC ß-lactamase. We evaluated characteristics, antibiotic utilization, and outcomes associated with battlefield-related E. cloacae infections (2009-2014). Single initial and serial E. cloacae isolates (≥24 hours from initial isolate from any site) associated with a clinical infection were examined. Susceptibility profiles of initial isolates in the serial isolation group were contrasted against last isolate recovered. Characteristics of 112 patients with E. cloacae infections (63 [56%] with single initial isolation; 49 [44%] with serial isolation) were compared to 509 patients with bacterial infections not attributed to E. cloacae. E. cloacae patients sustained more blast trauma (78%) compared to non-E. cloacae infections patients (75%; p<0.001); however, injury severity scores were comparable (median of 34.5 and 33, respectively; p = 0.334). Patients with E. cloacae infections had greater shock indices (median 1.07 vs 0.92; p = 0.005) and required more initial blood products (15 vs. 14 units; p = 0.032) compared to patients with non-E. cloacae infections. Although E. cloacae patients had less intensive care unit admissions (80% vs. 90% with non-E. cloacae infection patients; p = 0.007), they did have more operating room visits (5 vs. 4; p = 0.001), longer duration of antibiotic therapy (43.5 vs. 34 days; p<0.001), and lengthier hospitalizations (57 vs. 44 days; p<0.001). Patients with serial E. cloacae had isolation of infecting isolates sooner than patients with single initial E. cloacae (median of 5 vs. 8 days post-injury; p = 0.046); however, outcomes were not significantly different between the groups. Statistically significant resistance to individual antibiotics did not develop between initial and last isolates in the serial isolation group. Despite current combat care and surgical prophylaxis guidelines recommending upfront provision of AmpC-inducing antibiotics, clinical outcomes did not differ nor did significant antibiotic resistance develop in patients who experienced serial isolation of E. cloacae versus single initial isolation.
Assuntos
Cloaca , Enterobacter cloacae , Humanos , Animais , Antibacterianos/uso terapêutico , Hospitalização , Escala de Gravidade do FerimentoRESUMO
INTRODUCTION: Multidrug-resistant (MDR) Gram-negative infections complicate care of combat casualties. We describe the clinical characteristics, resistance patterns, and outcomes of Pseudomonas aeruginosa infections in combat casualties. METHODS: Combat casualties included in the Trauma Infectious Disease Outcomes Study with infections with and without P. aeruginosa isolation during initial hospitalization were compared. Pseudomonas aeruginosa from initial wound, blood, and serial isolates (≥7 days from previous isolate) collected from June 2009 through February 2014 was subjected to antimicrobial susceptibility testing, pulsed-field gel electrophoresis, and whole genome sequencing for assessing clonality. Multidrug resistance was determined using the CDC National Healthcare Safety Network definition. RESULTS: Of 829 combat casualties with infections diagnosed during initial hospitalization, 143 (17%) had P. aeruginosa isolated. Those with P. aeruginosa were more severely injured (median Injury Severity Score 33 [interquartile range (IQR) 27-45] vs 30 [IQR 18.5-42]; P < .001), had longer hospitalizations (median 58.5 [IQR 43-95] vs 38 [IQR 26-56] days; P < .001), and higher mortality (6.9% vs 1.5%; P < .001) than those with other organisms. Thirty-nine patients had serial P. aeruginosa isolation (median 2 subsequent isolates; IQR: 1-5), with decreasing antimicrobial susceptibility. Ten percent of P. aeruginosa isolates were MDR, associated with prior exposure to antipseudomonal antibiotics (P = .002), with amikacin and colistin remaining the most effective antimicrobials. Novel antimicrobials targeting MDR Gram-negative organisms were also examined, and 100% of the MDR P. aeruginosa isolates were resistant to imipenem/relabactam, while ceftazidime/avibactam and ceftolozane/tazobactam were active against 35% and 56% of the isolates, respectively. We identified two previously unrecognized P. aeruginosa outbreaks involving 13 patients. CONCLUSIONS: Pseudomonas aeruginosa continues to be a major cause of morbidity, affecting severely injured combat casualties, with emergent antimicrobial resistance upon serial isolation. Among MDR P. aeruginosa, active antimicrobials remain the oldest and most toxic. Despite ongoing efforts, outbreaks are still noted, reinforcing the crucial role of antimicrobial stewardship and infection control.
Assuntos
Infecções por Pseudomonas , Pseudomonas aeruginosa , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Farmacorresistência Bacteriana Múltipla , Humanos , Testes de Sensibilidade Microbiana , Infecções por Pseudomonas/tratamento farmacológico , Infecções por Pseudomonas/epidemiologiaRESUMO
The Acinetobacter baumannii-calcoaceticus complex (ABC) is associated with increasing carbapenem resistance, necessitating accurate resistance testing to maximize therapeutic options. We determined the accuracy of carbapenem antimicrobial susceptibility tests for ABC isolates and surveyed them for genetic determinants of carbapenem resistance. A total of 107 single-patient ABC isolates from blood and wound infections from 2006 to 2008 were evaluated. MICs of imipenem, meropenem, and doripenem determined by broth microdilution (BMD) were compared to results obtained by disk diffusion, Etest, and automated methods (the MicroScan, Phoenix, and Vitek 2 systems). Discordant results were categorized as very major errors (VME), major errors (ME), and minor errors (mE). DNA sequences encoding OXA beta-lactamase enzymes (bla(OXA-23-like), bla(OXA-24-like), bla(OXA-58-like), and bla(OXA-51-like)) and metallo-ß-lactamases (MBLs) (IMP, VIM, and SIM1) were identified by PCR, as was the KPC2 carbapenemase gene. Imipenem was more active than meropenem and doripenem. The percentage of susceptibility was 37.4% for imipenem, 35.5% for meropenem, and 3.7% for doripenem. Manual methods were more accurate than automated methods. bla(OXA-23-like) and bla(OXA-24-like) were the primary resistance genes found. bla(OXA-58-like), MBLs, and KPC2 were not present. Both automated testing and manual testing for susceptibility to doripenem were very inaccurate, with VME rates ranging between 2.8 and 30.8%. International variability in carbapenem breakpoints and the absence of CLSI breakpoints for doripenem present a challenge in susceptibility testing.
Assuntos
Acinetobacter baumannii/efeitos dos fármacos , Acinetobacter calcoaceticus/efeitos dos fármacos , Antibacterianos/farmacologia , Proteínas de Bactérias/genética , Carbapenêmicos/farmacologia , Testes de Sensibilidade Microbiana/métodos , beta-Lactamases/genética , Infecções por Acinetobacter/tratamento farmacológico , Infecções por Acinetobacter/microbiologia , Acinetobacter baumannii/isolamento & purificação , Acinetobacter calcoaceticus/isolamento & purificação , Antibacterianos/uso terapêutico , Carbapenêmicos/uso terapêutico , Doripenem , Farmacorresistência Bacteriana , Humanos , Imipenem/farmacologia , Meropeném , Tienamicinas/farmacologiaRESUMO
We determined minimum inhibitory concentrations of rifampicin, nitrofurantoin, amoxicillin-clavulanic acid, and cefdinir, plus a combination of amoxicillin-clavulanic acid and cefdinir by broth microdilution for mainly wound isolates of Escherichia coli and Klebsiella pneumoniae. E. coli and K. pneumoniae susceptibilities increased by combining amoxicillin-clavulanic acid and cefdinir.
Assuntos
Antibacterianos/farmacologia , Infecções por Enterobacteriaceae/microbiologia , Escherichia coli/efeitos dos fármacos , Klebsiella pneumoniae/efeitos dos fármacos , Administração Oral , Combinação Amoxicilina e Clavulanato de Potássio/farmacologia , Cefdinir , Cefalosporinas/farmacologia , Farmacorresistência Bacteriana Múltipla , Escherichia coli/isolamento & purificação , Humanos , Klebsiella pneumoniae/isolamento & purificação , Testes de Sensibilidade Microbiana , Nitrofurantoína/farmacologia , Rifampina/farmacologia , Infecção dos Ferimentos/microbiologiaRESUMO
Recent reclassification of the Klebsiella genus to include Klebsiella variicola, and its association with bacteremia and mortality, has raised concerns. We examined Klebsiella spp. infections among battlefield trauma patients, including occurrence of invasive K. variicola disease. Klebsiella isolates collected from 51 wounded military personnel (2009-2014) through the Trauma Infectious Disease Outcomes Study were examined using polymerase chain reaction (PCR) and pulsed-field gel electrophoresis. K. variicola isolates were evaluated for hypermucoviscosity phenotype by the string test. Patients were severely injured, largely from blast injuries, and all received antibiotics prior to Klebsiella isolation. Multidrug-resistant Klebsiella isolates were identified in 23 (45%) patients; however, there were no significant differences when patients with and without multidrug-resistant Klebsiella were compared. A total of 237 isolates initially identified as K. pneumoniae were analyzed, with 141 clinical isolates associated with infections (remaining were colonizing isolates collected through surveillance groin swabs). Using PCR sequencing, 221 (93%) isolates were confirmed as K. pneumoniae, 10 (4%) were K. variicola, and 6 (3%) were K. quasipneumoniae. Five K. variicola isolates were associated with infections. Compared to K. pneumoniae, infecting K. variicola isolates were more likely to be from blood (4/5 versus 24/134, p = 0.04), and less likely to be multidrug-resistant (0/5 versus 99/134, p<0.01). No K. variicola isolates demonstrated the hypermucoviscosity phenotype. Although K. variicola isolates were frequently isolated from bloodstream infections, they were less likely to be multidrug-resistant. Further work is needed to facilitate diagnosis of K. variicola and clarify its clinical significance in larger prospective studies.
Assuntos
Antibacterianos/uso terapêutico , Farmacorresistência Bacteriana Múltipla/genética , Infecções por Klebsiella/tratamento farmacológico , Klebsiella pneumoniae/genética , Klebsiella pneumoniae/patogenicidade , Klebsiella/genética , Klebsiella/patogenicidade , Lesões Relacionadas à Guerra/tratamento farmacológico , Infecção dos Ferimentos/tratamento farmacológico , Adulto , Bacteriemia/diagnóstico , Bacteriemia/tratamento farmacológico , Bacteriemia/epidemiologia , Bacteriemia/microbiologia , DNA Bacteriano/genética , DNA Bacteriano/isolamento & purificação , Alemanha/epidemiologia , Humanos , Klebsiella/isolamento & purificação , Infecções por Klebsiella/diagnóstico , Infecções por Klebsiella/epidemiologia , Klebsiella pneumoniae/isolamento & purificação , Masculino , Testes de Sensibilidade Microbiana , Militares , Filogenia , Reação em Cadeia da Polimerase , Estudos Retrospectivos , Resultado do Tratamento , Virulência/genética , Lesões Relacionadas à Guerra/diagnóstico , Lesões Relacionadas à Guerra/epidemiologia , Lesões Relacionadas à Guerra/microbiologia , Infecção dos Ferimentos/diagnóstico , Infecção dos Ferimentos/epidemiologia , Infecção dos Ferimentos/microbiologia , Adulto JovemRESUMO
Antimicrobial resistance is depleting the pharmacopeia of agents clinically useful against Gram-negative bacilli. As the number of active agents diminishes, accurate susceptibility testing becomes critical. We studied the susceptibilities of 107 isolates of the Acinetobacter baumannii-calcoaceticus complex to amikacin, gentamicin, and tobramycin using disk diffusion, Etest, as well as the Phoenix, Vitek 2, and MicroScan automated systems, and compared the results to those obtained by broth microdilution. Genes encoding aminoglycoside-modifying enzymes (AMEs) were detected by multiplex PCR, and clonal relationships were determined by pulsed-field gel electrophoresis. Tobramycin was the most active aminoglycoside (27.1% of isolates were susceptible). Disk diffusion and Etest tended to be more accurate than the Vitek 2, Phoenix, and MicroScan automated systems; but errors were noted with all methods. The Vitek 2 instrument incorrectly reported that more than one-third of the isolates were susceptible to amikacin (a very major error). Isolates were polyclonal, with 26 distinct strains, and carried multiple AME genes unrelated to the strain type. The presence of the ant(2")-Ia gene was statistically associated with resistance to each aminoglycoside. The AME genotype accounted for the resistance profile observed in a minority of isolates, suggesting the involvement of multiple resistance mechanisms. Hospital pharmacy records indicated the preferential use of amikacin over other aminoglycosides in the burn intensive care unit, where aminoglycoside resistance is prevalent. The resistance in that unit did not correlate with a predominant strain, AME genotype, or total annual aminoglycoside consumption. Susceptibility to tobramycin increased, even though susceptible isolates carried AME genotypes predicting the inactivation of tobramycin. Determination of the relative contribution of multiple concurrent resistance mechanisms may improve our understanding of aminoglycoside resistance in the Acinetobacter baumannii-calcoaceticus complex.
Assuntos
Acinetobacter baumannii/efeitos dos fármacos , Acinetobacter calcoaceticus/efeitos dos fármacos , Aminoglicosídeos/farmacologia , Antibacterianos/farmacologia , Erros de Diagnóstico/estatística & dados numéricos , Farmacorresistência Bacteriana , Acinetobacter baumannii/classificação , Acinetobacter baumannii/genética , Acinetobacter calcoaceticus/classificação , Acinetobacter calcoaceticus/genética , Adulto , Técnicas de Tipagem Bacteriana , Genes Bacterianos , Genótipo , Humanos , Testes de Sensibilidade Microbiana , Adulto JovemRESUMO
BACKGROUND: Staphylococcus aureus infections complicate care of combat-related injuries and can independently result in skin and soft-tissue infections during deployments or training. Community-associated methicillin-resistant S. aureus (CA-MRSA) strains seem to produce severe disease but retain susceptibility to many oral antimicrobials. This study characterizes 84 MRSA isolates recovered from wound cultures at a combat support hospital in Iraq. METHODS: MRSA strains recovered from December 2007 through March 2009 were analyzed. Antimicrobial resistance testing was determined by broth microdilution and the BD Phoenix Automated Microbiology System. The genotypic pattern was analyzed by pulsed-field gel electrophoresis and polymerase chain reaction identification of resistance and virulence genes. RESULTS: No MRSA isolates from wound cultures were resistant to vancomycin. The most active oral antistaphylococcal agents were tetracycline (95% susceptibility), trimethoprim-sulfamethoxazole (94%), and clindamycin (94%). Of agents not typically recommended as monotherapy, 98% of isolates were susceptible to rifampin, 91% to moxifloxacin, and 60% to levofloxacin. The most common pulsed-field type (PFT) was USA300 (79%). The typical staphylococcal cassette chromosome mec IV elements carrying the CA-MRSA resistance genes were present in 88% of the isolates. Panton-Valentine leukocidin virulence genes were identified in 88% of isolates, including 100% of PFT USA300. The virulence gene associated with an arginine catabolic mobile element was present in 75% of isolates, including 94% of PFT USA300. CONCLUSION: This study is the first genotypic and phenotypic characterization of CA-MRSA recovered from wound cultures in a deployed combat hospital. The pattern noted was similar to that seen in soldiers stationed in the United States.
Assuntos
Hospitais Militares , Guerra do Iraque 2003-2011 , Resistência a Meticilina , Staphylococcus aureus Resistente à Meticilina/isolamento & purificação , Alta do Paciente , Infecções Estafilocócicas/microbiologia , Infecção dos Ferimentos/microbiologia , DNA Bacteriano/análise , Eletroforese em Gel de Campo Pulsado , Genótipo , Humanos , Incidência , Staphylococcus aureus Resistente à Meticilina/genética , Reação em Cadeia da Polimerase , Valor Preditivo dos Testes , Prognóstico , Estudos Retrospectivos , Infecções Estafilocócicas/epidemiologia , Estados Unidos/epidemiologia , Infecção dos Ferimentos/epidemiologiaRESUMO
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.