Effects of combined ciprofloxacin and Neulasta therapy on intestinal pathology and gut microbiota after high-dose irradiation in mice.

Introduction: Treatments that currently exist in the strategic national stockpile for acute radiation syndrome (ARS) focus on the hematopoietic subsyndrome, with no treatments on gastrointestinal (GI)-ARS. While the gut microbiota helps maintain host homeostasis by mediating GI epithelial and mucosal integrity, radiation exposure can alter gut commensal microbiota which may leave the host susceptible to opportunistic pathogens and serious sequelae such as sepsis. To mitigate the effects of hematopoietic ARS irradiation, currently approved treatments exist in the form of colony stimulating factors and antibiotics: however, there are few studies examining how these therapeutics affect GI-ARS and the gut microbiota. The aim of our study was to examine the longitudinal effects of Neulasta and/or ciprofloxacin treatment on the gut microbiota after exposure to 9.5 Gy 60Co gamma-radiation in mice. Methods: The gut microbiota of vehicle and drug-treated mice exposed to sham or gamma-radiation was characterized by shotgun sequencing with alpha diversity, beta diversity, and taxonomy analyzed on days 2, 4, 9, and 15 post-irradiation. Results: No significant alpha diversity differences were observed following radiation, while beta diversity shifts and taxonomic profiles revealed significant alterations in Akkermansia, Bacteroides, and Lactobacillus. Ciprofloxacin generally led to lower Shannon diversity and Bacteroides prevalence with increases in Akkermansia and Lactobacillus compared to vehicle treated and irradiated mice. While Neulasta increased Shannon diversity and by day 9 had more similar taxonomic profiles to sham than ciprofloxacin-or vehicle-treated irradiated animals. Combined therapy of Neulasta and ciprofloxacin induced a decrease in Shannon diversity and resulted in unique taxonomic profiles early post-irradiation, returning closer to vehicle-treated levels over time, but persistent increases in Akkermansia and Bacteroides compared to Neulasta alone. Discussion: This study provides a framework for the identification of microbial elements that may influence radiosensitivity, biodosimetry and the efficacy of potential therapeutics. Moreover, increased survival from H-ARS using these therapeutics may affect the symptoms and appearance of what may have been subclinical GI-ARS.

The military gear microbiome: risk factors surrounding the warfighter.

Combat extremity wounds are highly susceptible to contamination from surrounding environmental material. This bioburden could be partially transferred from materials in immediate proximity to the wound, including fragments of the uniform and gear. However, the assessment of the microbial bioburden present on military gear during operational conditions of deployment or training is relatively unexplored. Opportunistic pathogens that can survive on gear represent risk factors for infection following injury, especially following combat blasts, where fibers and other materials are embedded in wounded tissue. We utilized 16S rRNA sequencing to assess the microbiome composition of different military gear types (boot, trouser, coat, and canteen) from two operational environments (training in Hawai'i and deployed in Indonesia) across time (days 0 and 14). We found that microbiome diversity, stability, and composition were dependent on gear type, training location, and sampling timepoint. At day 14, species diversity was significantly higher in Hawai'i samples compared to Indonesia samples for boot, coat, and trouser swabs. In addition, we observed the presence of potential microbial risk factors, as opportunistic pathogenic species, such as Acinetobacter, Pseudomonas, and Staphylococcus, were found to be present in all sample types and in both study sites. These study outcomes will be used to guide the design of antimicrobial materials and uniforms and for infection control efforts following combat blasts and other injuries, thereby improving treatment guidance during military training and deployment.IMPORTANCECombat extremity wounds are vulnerable to contamination from environments of proximity to the warfighter, leading to potential detrimental outcomes such as infection and delayed wound healing. Therefore, microbial surveillance of such environments is necessary to aid the advancement of military safety and preparedness through clinical diagnostics, treatment protocols, and uniform material design.

Meta-Analysis of Publicly Available Clinical and Preclinical Microbiome Data From Studies of Burn Injury.

Following burn injury, alterations in host commensal microbiota across body spaces may leave patients susceptible to opportunistic pathogens and serious sequelae such as sepsis. Generally, studies examining the microbiome postburn have had a limited sample size and lack of longitudinal data, which coupled with experimental and analytic variation, impacts overall interpretation. We performed a meta-analysis of publicly available sequencing data from preclinical and clinical burn studies to determine if there were consistent alterations in the microbiome across various anatomical sites and hosts. Ten human and animal 16S rRNA sequencing studies spanning respiratory, urinary, cutaneous, and gastrointestinal microbiomes were included. Taxonomic classification and alpha and beta diversity metrics were analyzed using QIIME2 v2021.8. Alpha diversity was consistently higher in control samples compared to burn-injured samples which were also different based on host and anatomical location; however, phylogenetic evaluation (ie, Faith PD) elucidated more significant differences compared to taxonomic metrics (ie, Shannon entropy). Beta diversity analysis based on weighted UniFrac showed that rodent specimens clustered less closely to humans than pig samples for both rectal and skin sources. Host species and performing institute were found to have a significant impact on community structure. In rectal samples, bacterial composition in pig and human burn samples included Bacteroidetes, Firmicutes, and Proteobacteria, while rodent samples were dominated by Firmicutes. Proteobacteria and Firmicutes increased on burned skin in each host species. Our results suggest that host species and the performing institute strongly influence microbiome structure. Burn-induced alterations in microbiome diversity and taxa exist across hosts, with phylogenetic metrics more valuable than others. Coordinated, multicenter studies, both clinical and preclinical, within the burn community are needed to more completely realize the diagnostic and therapeutic potential of the microbiome for improving outcomes postburn.

Effect of SARs-CoV-2 pandemic on infection prevention behaviors and bacterial burden of high touch surfaces in a medical/surgical setting.

This study aimed to determine the longitudinal efficacy of ultraviolet germicidal disinfection (UV-C) in a non-terminal disinfection context. Moreover, factors influencing enhanced infection prevention behaviors during the SARS-CoV-2 pandemic were evaluated. Sixty nursing staff from three medical/surgical wards in a large military hospital were recruited for a survey and microbiological sampling of high-touch surfaces (stethoscope, personal electronic device, common access card, and hospital ID badge) and portable medical equipment (wheelchairs and mobile commodes). Surveys included hand hygiene estimates, frequency/method of cleaning items of interest, perception of UV-C, and factors influencing the use of enhanced disinfection tools. Surveys and microbiological samples were performed prior to and after the installation of a rapid, automated ultraviolet disinfection enclosure for staff use. Both time points preceded the SARS-CoV-2 pandemic in the United States. A final survey/sampling time point was carried out eight months after the declaration of the COVID-19 pandemic. Participants' hand hygiene frequency did not increase throughout the study, with > 80% reporting a minimum of 4 hand hygiene events per patient hour. The cleaning frequency of high-touch surfaces (non-clinical) but not portable medical equipment increased after installation of a UV-C disinfection tool and was sustained eight months into the COVID-19 pandemic. While a modest decrease in bacterial burden was observed after UV-C intervention, a more significant reduction was observed across all surfaces during pandemic time sampling, though no detectable decrease in pathogenic contamination was observed at either time point. Motivators of UV-C use included fear of SARS-CoV-2 contamination and transmission, ease of device use, and access to rapid, automated disinfection tools while deterrents reported included technical concerns, lack of time, and preference for other disinfection methods. Automated, rapid-cycle UV-C disinfection can be efficacious for high-touch surfaces not currently governed by infection prevention and control guidelines. The introduction of enhanced disinfection tools like UV-C can enhance the overall cleaning frequency and is correlated with mild decreases in bacterial burden of high-touch surfaces, this is enhanced during periods of heightened infection threat. Evidence from this study offers insights into the factors which prompt healthcare workers to internalize/dismiss enhanced infection prevention procedures.

Respiratory Viral Pathogens Among U.S. Military Personnel at a Medical Treatment Facility in Hawaii From 2014 to 2019.

INTRODUCTION: Acute respiratory diseases account for a substantial number of outpatient visits and hospitalizations among U.S. military personnel, significantly affecting mission readiness and military operations. We conducted a retrospective analysis of respiratory viral pathogen (RVP) samples collected from U.S. military personnel stationed in Hawaii and tested at Tripler Army Medical Center from January 2014 to May 2019 in order to describe the etiology, distribution, and seasonality of RVP exposure in a military population. MATERIALS AND METHODS: Samples were analyzed by viral culture or multiplex PCR. Distribution of respiratory viruses over time was analyzed as well as subject demographic and encounter data. Presenting signs and symptoms were evaluated with each RVP. RESULTS: A total of 2,576 military personnel were tested, of which 726 (28.2%) were positive for one or more RVP. Among positive tests, the three most common viral pathogens detected were influenza A (43.0%), rhinovirus (24.5%), and parainfluenza (7.6%). Symptoms were generally mild and most frequently included cough, fever, and body aches. CONCLUSION: Our study evaluated respiratory virus prevalence, seasonality, and association with clinical symptoms for military personnel in an urban tropical setting in Oahu, HI, over a 5-year period. We show that viral prevalence and seasonality in Hawaii are distinct from those of the CONUS. Results contribute to the broader understanding of seasonality, clinical manifestation, and demographics of RVP among active duty military personnel stationed in Hawaii.

The prevalence of M. tuberculosis among acid fast bacilli cultures from military health system and veterans affairs beneficiaries in Hawaii and the Pacific Islands from 2002 to 2019.

The prevalence of tuberculosis among military health system (MHS) and Veterans Affairs (VA) beneficiaries in Hawaii and the Pacific Islands has not been previously reported. Our analysis evaluates the prevalence of M. tuberculosis (MTB) among acid fast bacilli culture(s) (AFB) tested at Tripler Army Medical Center (TAMC) on Oahu, HI and describes demographic factors associated with positive samples. We analyzed 9,768 AFBs from 4,129 individuals with AFB specimens processed at TAMC from January 2002 to November 2019: of those who were tested 3,178 were MHS beneficiaries and 951 were VA beneficiaries. There were a total of 40 individuals with MTB-positive cultures over the period of study: 31 MHS beneficiaries and 9 VA beneficiaries. Of the MTB-positive specimens, 93% were from pulmonary samples while the remainder were from lymph node aspirates (5%) and peritoneal samples (2%). Cumulative incidence rates of MTB-isolation were 1.8 per 100,000 MHS beneficiaries and 1.2 per 100,000 VA beneficiaries, both of which were lower than reported incidence rates in Hawaii, the U.S.-affiliated Pacific Islands and the United States for the study period. MHS beneficiaries of Asian-Pacific Islander race or ethnicity had nearly 20 times higher odds of positive AFB than white MHS beneficiaries (OR = 19.56, 95% CI 5.52, 69.29, p = < 0.001). This study demonstrated a higher odds of MTB-positivity associated with Asian-Pacific Islander race or ethnicity and low incidence rates of TB among MHS and VA beneficiaries in Hawaii and the Pacific Islands when compared with the civilian population.

Prevalence and Epidemiology of Mycoplasma genitalium in a Pacific-Region Military Population.

BACKGROUND: Mycoplasma genitalium is an important emerging sexually transmitted pathogen commonly causing urethritis in men, cervicitis, and pelvic inflammatory disease in women with potential of infertility. Accumulating evidence identifies the prevalence of M. genitalium similar to long recognized pathogens, Chlamydia trachomatis and Neisseria gonorrhoeae. The purpose of this study was to establish the prevalence and epidemiology of M. genitalium in a mid-Pacific military population. METHODS: A prospective analysis was conducted from routine specimens collected as standard of care for sexually transmitted infection (STI) testing at Tripler Army Medical Center on Oahu, HI. The prevalence of M. genitalium was determined using the Aptima M. genitalium assay, a transcription-mediated amplification test. A multivariate analysis was performed to assess the associations for this infection with other STIs and demographic factors. RESULTS: A total of 1876 specimens were tested in a 6-month period including 6 sample types from 1158 females and 718 males. Subject ages ranged from 18 to 76 years, with a median of 24 years (interquartile range, 21-29 years). The prevalence of M. genitalium was 8.8% overall (n = 165), 7.1% in females and 11.6% in males. Coinfection with M. genitalium occurred with another sexually-transmitted pathogen in 43 patients (18.3%), with C. trachomatis as the most common organism (n = 38). CONCLUSIONS: These data contribute to the evidence base for M. genitalium and STI screening in an active-duty military.

Antibiofilm activity of chitosan/epsilon-poly-L-lysine hydrogels in a porcine ex vivo skin wound polymicrobial biofilm model.

As antibiotic resistance continues to increase globally, there is an urgency for novel, non-antibiotic approaches to control chronic drug-resistant infections, particularly those associated with polymicrobial biofilm formation in chronic wounds. Also needed are clinically relevant polymicrobial biofilm models that can be utilized to assess the efficacy of innovative therapeutics against mature biofilms. We successfully developed a highly reproducible porcine ex vivo skin wound polymicrobial biofilm model using clinical isolates of multidrug-resistant Pseudomonas aeruginosa, methicillin-resistant Staphylococcus aureus, and Candida albicans. This ex vivo biofilm model was then used to assess the antimicrobial and antibiofilm properties of an easily fabricated chitosan hydrogel incorporating the natural antimicrobial peptide epsilon-poly-L-lysine. Antimicrobial activity was evaluated against planktonic cultures in vitro and against mature biofilms ex vivo. The antibiofilm efficiency of the hydrogels was especially pronounced against Pseudomonas aeruginosa, whose counts were reduced by 99.98% after 2 hours in vitro and by 99.94% after treatment for 24 hours when applied to 24 hour ex vivo polymicrobial wound biofilms. The activity of the hydrogels was lower against Staphylococcus aureus and ineffective against Candida albicans. Gram, Hucker-Twort staining of paraffin sections revealed balanced polymicrobial communities in mature 48 hour untreated biofilms. Treatment of 48 or 72 hour biofilms for 2 or 3 days with hydrogels that were applied within 5 hours after inoculation resulted in an impressive 96% and 97% reduction in biofilm thickness compared to untreated biofilms, respectively (P < .001). Likewise, topical gel treatment for 24 hours reduced biofilm thickness by 84% and 70%, respectively, when applied to mature biofilms at 24 and 48 hours after inoculation (P < .001). Thus, this ex vivo wound biofilm model provides a useful means to assess the efficacy of novel treatments to prevent and eradicate polymicrobial biofilms consisting of multidrug-resistant Pseudomonas aeruginosa, methicillin-resistant Staphylococcus aureus, and Candida albicans.

A Longitudinal Evaluation of the Bacterial Pathogens Colonizing Chronic Non-Healing Wound Sites at a United States Military Treatment Facility in the Pacific Region.

PURPOSE: The biology of chronic wounds is complex and many factors act concurrently to impede healing progress. In this study, the dynamics of microflora changes and their antibiotic susceptibility patterns were evaluated longitudinally over 30 days using data from 28 patients with a total of 47 chronic lower extremity wounds. MATERIALS AND METHODS: In this study, colonized wound isolates were characterized using cultural, biochemical, and VITEK 2 methods. Antibiotic susceptibility patterns of the wound isolates were analyzed using various phenotypic assays. Furthermore, antimicrobial resistance patterns and the presence of mutations were evaluated by a genotypic assay, whole-genome sequencing (WGS). RESULTS: Staphylococcus aureus and Pseudomonas aeruginosa were found to be the most common strains at early time points, while members of Enterobacteriaceae were prevalent at later stages of infection. Antimicrobial resistance testing and whole-genome sequencing revealed that the molecular and phenotypic characteristics of the identified wound pathogens remained relatively stable throughout the study period. It was also noted that Enterobacter and Klebsiella species may serve as reservoirs for quinolone resistance in the Pacific region. CONCLUSION: Our observations showed that wounds were colonized with diverse bacteria and interestingly their numbers and/or types were changed over the course of infection. The rapid genetic changes that accompanied the first 4 weeks after presentation did not directly contribute to the development of antibiotic resistance. In addition, standard wound care procedures did not appear to select for resistant bacterial strains. Future efforts should focus on defining those genetic changes associated with the wound colonizing microorganisms that occur beyond 4 weeks.

3D printing of face shields to meet the immediate need for PPE in an anesthesiology department during the COVID-19 pandemic.

BACKGROUND: Anesthesia providers are at risk for contracting COVID-19 due to close patient contact, especially during shortages of personal protective equipment. We present an easy to follow and detailed protocol for producing 3D printed face shields and an effective decontamination protocol, allowing their reuse. METHODS: The University of Nebraska Medical Center (UNMC) produced face shields using a combination of 3D printing and assembly with commonly available products, and produced a simple decontamination protocol to allow their reuse. To evaluate the effectiveness of the decontamination protocol, we inoculated bacterial suspensions of E. coli and S. aureus on to the face shield components, performed the decontamination procedure, and finally swabbed and enumerated organisms onto plates that were incubated for 12-24 hours. Decontamination effectiveness was evaluated using the average log10 reduction in colony counts. RESULTS: Approximately 112 face shields were constructed and made available for use in 72 hours. These methods were successfully implemented for in-house production at UNMC and at Tripler Army Medical Center (Honolulu, Hawaii). Overall, the decontamination protocol was highly effective against both E. coli and S. aureus, achieving a ≥4 log10 (99.99%) reduction in colony counts for every replicate from each component of the face shield unit. DISCUSSION: Face shields not only act as a barrier against the soiling of N95 face masks, they also serve as more effective eye protection from respiratory droplets over standard eye shields. Implementation of decontamination protocols successfully allowed face shield and N95 mask reuse, offering a higher level of protection for anesthesiology providers at the onset of the COVID-19 pandemic. CONCLUSIONS: In a time of urgent need, our protocol enabled the rapid production of face shields by individuals with little to no 3D printing experience, and provided a simple and effective decontamination protocol allowing reuse of the face shields.

Respiratory Viral Pathogens in Children Evaluated at Military Treatment Facilities in Oahu, Hawaii From 2014 to 2018: Seasonality and Climatic Factors.

Five-year retrospective analysis of respiratory viruses in children less than 18 years old at Tripler Army Medical Center and outlying clinics in Oahu. Respiratory syncytial virus and influenza A showed pronounced seasonality with peaks from September to December and December to March, respectively. Results provide a better understanding of the timing of viral preventive strategies in Oahu.

Rapid qualitative antibiotic resistance characterization using VITEK MS.

Development and standardization of simple, timely, and cost-effective antibiotic susceptibility assays are much needed to address the emergence of global resistance. The use of matrix-assisted laser desorption/ionization time of flight mass spectrometry is routine for bacterial identification. This study evaluated 2 assays using the VITEK MS for rapid detection and accurate differentiation of bacterial antibiotic susceptibility. We describe an extraction method and direct-on-target microdroplet growth assay (DOT-MGA). Non-susceptible and susceptible strains of Staphylococcus aureus, Enterococcus species, Escherichia coli, and Klebsiella pneumoniae were tested. The liquid extraction method and DOT-MGA proved to be reliable assays providing consistent differentiation between non-susceptible and susceptible strains. Results from this study support VITEK MS and these assays as rapid and accurate tools to augment traditional susceptibility testing. If implemented clinically, these assays can reduce the cost of patient care and the time to deliver critically needed treatment.

Assessment of surgical instrument bioburden after steam sterilization: A pilot study.

In environments in which manual decontamination and steam sterilization remains the primary method of sterilization, biofilm formation can increase the risk of disease transmission. To determine the risk of bacterial survival and contamination on surgical instruments, inoculated blood was dried on one instrument and steam sterilized (wrapped or unwrapped) in a set of 4 (including 3 clean). Two of 3 pathogens were recovered at a rate of 15% for unwrapped sets and 33% for wrapped sets.

Comparative effectiveness of rapid-cycle ultraviolet decontamination to chemical decontamination on high-touch communication devices.

BACKGROUND: This quantitative, comparative-descriptive study of inpatient units in a large military medical center was designed to compare the effectiveness of compact ultraviolet (UV-C) decontamination to standard chemical decontamination in reducing the microbial burden on Vocera (San Jose, CA) communication devices and to characterize changes in staff cleaning practices following UV-C device implementation. METHODS: Aerobic and anaerobic swabs were used to collect microbial samples from Vocera devices (n = 60) before and after chemical decontamination (first sampling) and before and after UV decontamination (second sampling). Cleaning behaviors were assessed by observation and oral inquiry during the baseline sampling and surveyed 8 weeks after UV-C device implementation. Outcomes included aerobic and anaerobic colony-forming units and prevalence of methicillin-resistant Staphylococcus aureus, vancomycin-resistant enterococci, or Clostridium difficile, as determined by standard microbiological methods. RESULTS: No differences were found between the two cleaning methods in their ability to reduce aerobic bacteria; however, UV-C was significantly more effective at reducing bacteria grown anaerobically (P < .01). This study elucidated an 8.3% prevalence of methicillin-resistant Staphylococcus aureus on Vocera devices in the inpatient environment. Initially, 42% of respondents reported deviations from manufacturer's cleaning guidelines, and 16.7% reported daily or more frequent cleaning of the Vocera devices. CONCLUSIONS: After implementation, UV-C decontamination reduced average cleaning time by 43% and increased the rate of daily Vocera cleaning to 86.5%. Respondents reported an overall 98% user satisfaction with the UV-C device.