The Effect of Preoperative Chlorhexidine Gluconate Cleanse on Lower Extremity Surgical Site Infections: A Retrospective Cohort Study

BACKGROUND

Lower extremity surgical sites are at an increased risk of wound infection following Mohs micrographic surgery.

OBJECTIVE

To evaluate the rate of lower extremity surgical site infections following a 14-day regimen of preoperative 4% chlorhexidine gluconate (CHG) rinses and postoperative wound occlusion for 14 days.

MATERIALS AND METHODS

Retrospective data were collected from procedures performed by the senior author from January 2022 through June 2023. To meet inclusion, patients must have completed waist-down CHG soak and rinse for 14 days before surgery, including the day before surgery. In addition, the patient must have kept the dressing clean, dry, and intact until the postoperative appointment at 14 days.

RESULTS

A total of 100 Mohs cases met inclusion criteria. Zero patients developed a surgical site infection.

CONCLUSION

Chlorhexidine gluconate preoperative rinsing and postoperative occlusion for 14 days may minimize the risk of wound infection. Although further research is indicated, an opportunity exists for the adoption of CHG into routine clinical practice in the outpatient dermatology setting.

The Host-Pathogen Interplay: A Tale of Two Stories within the Cornea and Posterior Segment

Ocular infectious diseases are an important cause of potentially preventable vision loss and blindness. In the following manuscript, we will review ocular immunology and the pathogenesis of herpesviruses and Pseudomonas aeruginosa infections of the cornea and posterior segment. We will highlight areas of future research and what is currently known to promote bench-to-bedside discoveries to improve clinical outcomes of these debilitating ocular diseases.

Stability Characterization of the Novel Anti-Cancer HM-10/10 HDL-Mimetic Peptide

Epithelial adenocarcinoma of the ovary and colon are associated with the highest rates of cancer-related deaths in women in the U.S. The literature supports the role of HDL-associated apolipoproteins in the treatment of cancer and other pro-inflammatory diseases. Previously, we developed a novel 20-amino acid mimetic peptide, HM-10/10, which potently inhibits tumor development and growth in colon and ovarian cancer. Here, we report the properties of HM-10/10 relative to its stability in vitro. The results demonstrated that HM-10/10 had the highest half-life in human plasma compared to plasma from other species tested. HM-10/10 demonstrated stability in human plasma and simulated gastric environment, increasing its promise as an oral pharmaceutical. However, under conditions modeling the small intestine, HM-10/10 demonstrated significant degradation, likely due to the peptidases encountered therein. Furthermore, HM-10/10 demonstrated no evidence of time-dependent drug-drug interactions, although it demonstrated CYP450 induction slightly above cutoff. As proteolytic degradation is a common limitation of peptide-based therapeutics, we are pursuing strategies to improve the stability properties of HM-10/10 by extending its bioavailability while retaining its low toxicity profile. HM-10/10 holds promise as a new agent to address the international women's health crisis of epithelial carcinomas of the ovary and colon.

Differentiation of Francisella tularensis Subspecies and Subtypes

The highly infectious and zoonotic pathogen Francisella tularensis is the etiologic agent of tularemia, a potentially fatal disease if untreated. Despite the high average nucleotide identity, which is >99.2% for the virulent subspecies and >98% for all four subspecies, including the opportunistic microbe Francisella tularensis subsp. novicida, there are considerable differences in genetic organization. These chromosomal disparities contribute to the substantial differences in virulence observed between the various F. tularensis subspecies and subtypes. The methods currently available to genotype F. tularensis cannot conclusively identify the associated subpopulation without using time-consuming testing or complex scoring matrices. To address this need, we developed both single and multiplex quantitative real-time PCR (qPCR) assays that can accurately detect and identify the hypervirulent F. tularensis subsp. tularensis subtype A.I, the virulent F. tularensis subsp. tularensis subtype A.II, F. tularensis subsp. holarctica (also referred to as type B), and F. tularensis subsp. mediasiatica, as well as opportunistic F. tularensis subsp. novicida from each other and near neighbors, such as Francisella philomiragia, Francisella persica, and Francisella-like endosymbionts found in ticks. These fluorescence-based singleplex and non-matrix scoring multiplex qPCR assays utilize a hydrolysis probe, providing sensitive and specific F. tularensis subspecies and subtype identification in a rapid manner. Furthermore, sequencing of the amplified F. tularensis targets provides clade confirmation and informative strain-specific details. Application of these qPCR- and sequencing-based detection assays will provide an improved capability for molecular typing and clinical diagnostics, as well as facilitate the accurate identification and differentiation of F. tularensis subpopulations during epidemiological investigations of tularemia source outbreaks.

Individuals with CYP2C8 and CYP2C9 reduced metabolism haplotypes self-adjusted ibuprofen dose in the Coriell Personalized Medicine Collaborative

OBJECTIVES

The objectives of this study were to determine whether differences in CYP2C8 and CYP2C9 haplotype influence the dose of ibuprofen self-administered by individuals, and to examine the potential relationship between CYP2C8 and CYP2C9 reduced metabolism haplotypes and adverse events.

PARTICIPANTS AND METHODS

We investigated relationships between genetic variations in CYP2C8 and CYP2C9 and ibuprofen use, dose, and side effects (reported by questionnaire) in 445 participants from the Coriell Personalized Medicine Collaborative.

RESULTS

Carriers of reduced metabolism haplotypes for CYP2C8 (*2, *3, *4) and CYP2C9 (*2, *3) were significantly (P=0.0171) more likely than those lacking these variants to take less than the recommended dose of ibuprofen, after controlling for sex, age, race, and cohort. In contrast to ibuprofen dose, there were no differences in ibuprofen use frequency or reported side effects based on haplotype. However, there are often no early signs of acute kidney injury, the most serious side effect of elevated ibuprofen exposure.

CONCLUSION

These results suggest a subset of individuals with genetic variation in CYP2C8 and CYP2C9 recognize that they obtain adequate drug efficacy with lower ibuprofen doses, or take lower doses due to prior side effects. However, most (82.6%) individuals with reduced metabolism haplotypes nonetheless took recommended or higher doses, potentially putting them at increased risk for side effects.

rs11670527 Upstream of ZNF264 Associated with Body Mass Index in the Coriell Personalized Medicine Collaborative

INTRODUCTION

the effects of obesity on health are a concern for the military as they affect the fitness to serve of active service members, increase costs to the Military Health System, and reduce quality of life for veterans and beneficiaries. Although obesity can be influenced by behavioral and environmental factors, it has also been shown to be associated with genetic risk factors that are not fully understood.

MATERIALS AND METHODS

we performed a genome-wide association study of 5,251 participants in the Coriell Personalized Medicine Collaborative, which includes 2,111 Air Force participants. We applied a generalized linear model, using principal component analysis to account for population structure, and analyzed single-variant associations with body mass index (BMI) as a continuous variable, using a Bonferroni-corrected P-value threshold to account for multiplicity.

RESULTS

we identified one genome-wide significant locus, rs11670527, upstream of the ZNF264 gene on chromosome 19, associated with BMI.

CONCLUSIONS

the finding of an association between rs11670527 and BMI adds to the growing body of literature characterizing the complex genetics of obesity. These efforts may eventually inform personalized interventions aimed at achieving and maintaining healthy weight.

Francisella tularensis Subtype A.II Genomic Plasticity in Comparison with Subtype A.I

Although Francisella tularensis is considered a monomorphic intracellular pathogen, molecular genotyping and virulence studies have demonstrated important differences within the tularensis subspecies (type A). To evaluate genetic variation within type A strains, sequencing and assembly of a new subtype A.II genome was achieved for comparison to other completed F. tularensis type A genomes. In contrast with the F. tularensis A.I strains (SCHU S4, FSC198, NE061598, and TI0902), substantial genomic variation was observed between the newly sequenced F. tularensis A.II strain (WY-00W4114) and the only other publically available A.II strain (WY96-3418). Genome differences between WY-00W4114 and WY96-3418 included three major chromosomal translocations, 1580 indels, and 286 nucleotide substitutions of which 159 were observed in predicted open reading frames and 127 were located in intergenic regions. The majority of WY-00W4114 nucleotide deletions occurred in intergenic regions, whereas most of the insertions and substitutions occurred in predicted genes. Of the nucleotide substitutions, 48 (30%) were synonymous and 111 (70%) were nonsynonymous. WY-00W4114 and WY96-3418 nucleotide polymorphisms were predominantly G/C to A/T allelic mutations, with WY-00W4114 having more A+T enrichment. In addition, the A.II genomes contained a considerably higher number of intact genes and longer repetitive sequences, including transposon remnants than the A.I genomes. Together these findings support the premise that F. tularensis A.II may have a fitness advantage compared to the A.I subtype due to the higher abundance of functional genes and repeated chromosomal sequences. A better understanding of the selective forces driving F. tularensis genetic diversity and plasticity is needed.

Proximal-type epithelioid sarcoma: case report of an unusual presentation

Epithelioid sarcoma, first described by Enzinger in 1970, classically presents in young adults and usually arises in the distal extremities. The proximal-type variant, first described in 1997 as a rare aggressive form of sarcoma, usually arises more proximally. It carries a higher mortality rate than classical limb epithelioid sarcoma and is often resistant to multimodal treatment. We report the case of a 27-year old male who had a delayed diagnosis of proximal-type epithelioid sarcoma of the forearm. This was originally thought to be a necrotising soft tissue infection and was unfortunately metastatic at the time of eventual diagnosis. The clinical and histopathological features of this challenging tumour are discussed and the relevant literature is reviewed.

Francisella tularensis molecular typing using differential insertion sequence amplification

Tularemia is a potentially fatal disease that is caused by the highly infectious and zoonotic pathogen Francisella tularensis. Despite the monomorphic nature of sequenced F. tularensis genomes, there is a significant degree of plasticity in the organization of genetic elements. The observed variability in these genomes is due primarily to the transposition of direct repeats and insertion sequence (IS) elements. Since current methods used to genotype F. tularensis are time-consuming and require extensive laboratory resources, IS elements were investigated as a means to subtype this organism. The unique spatial location of specific IS elements provided the basis for the development of a differential IS amplification (DISA) assay to detect and distinguish the more virulent F. tularensis subsp. tularensis (subtypes A.I and A.II) and subsp. holarctica (type B) strains from F. tularensis subsp. novicida and other near neighbors, including Francisella philomiragia and Francisella-like endosymbionts found in ticks. Amplicon sizes and sequences derived from DISA showed heterogeneity within members of the subtype A.I and A.II isolates but not the type B strains. These differences were due to a 312-bp fragment derived from the IS element ISFtu1. Analysis of wild-type F. tularensis isolates by DISA correlated with pulsed-field gel electrophoresis genotyping utilizing two different restriction endonucleases and provided rapid results with minimal sample processing. The applicability of this molecular typing assay for environmental studies was demonstrated by the accurate identification and differentiation of tick-borne F. tularensis. The described approach to IS targeting and amplification provides new capability for epidemiological investigations and characterizations of tularemia source outbreaks.

Large direct repeats flank genomic rearrangements between a new clinical isolate of Francisella tularensis subsp. tularensis A1 and Schu S4

Francisella tularensis subspecies tularensis consists of two separate populations A1 and A2. This report describes the complete genome sequence of NE061598, an F. tularensis subspecies tularensis A1 isolated in 1998 from a human with clinical disease in Nebraska, United States of America. The genome sequence was compared to Schu S4, an F. tularensis subspecies tularensis A1a strain originally isolated in Ohio in 1941. It was determined that there were 25 nucleotide polymorphisms (22 SNPs and 3 indels) between Schu S4 and NE061598; two of these polymorphisms were in potential virulence loci. Pulsed-field gel electrophoresis analysis demonstrated that NE061598 was an A1a genotype. Other differences included repeat sequences (n = 11 separate loci), four of which were contained in coding sequences, and an inversion and rearrangement probably mediated by insertion sequences and the previously identified direct repeats I, II, and III. Five new variable-number tandem repeats were identified; three of these five were unique in NE061598 compared to Schu S4. Importantly, there was no gene loss or gain identified between NE061598 and Schu S4. Interpretation of these data suggests there is significant sequence conservation and chromosomal synteny within the A1 population. Further studies are needed to determine the biological properties driving the selective pressure that maintains the chromosomal structure of this monomorphic pathogen.

Complete genome sequence of Francisella tularensis subspecies holarctica FTNF002-00

Francisella tularensis subspecies holarctica FTNF002-00 strain was originally obtained from the first known clinical case of bacteremic F. tularensis pneumonia in Southern Europe isolated from an immunocompetent individual. The FTNF002-00 complete genome contains the RD₂₃ deletion and represents a type strain for a clonal population from the first epidemic tularemia outbreak in Spain between 1997–1998. Here, we present the complete sequence analysis of the FTNF002-00 genome. The complete genome sequence of FTNF002-00 revealed several large as well as small genomic differences with respect to two other published complete genome sequences of F. tularensis subsp. holarctica strains, LVS and OSU18. The FTNF002-00 genome shares >99.9% sequence similarity with LVS and OSU18, and is also ∼5 MB smaller by comparison. The overall organization of the FTNF002-00 genome is remarkably identical to those of LVS and OSU18, except for a single 3.9 kb inversion in FTNF002-00. Twelve regions of difference ranging from 0.1–1.5 kb and forty-two small insertions and deletions were identified in a comparative analysis of FTNF002-00, LVS, and OSU18 genomes. Two small deletions appear to inactivate two genes in FTNF002-00 causing them to become pseudogenes; the intact genes encode a protein of unknown function and a drug:H⁺ antiporter. In addition, we identified ninety-nine proteins in FTNF002-00 containing amino acid mutations compared to LVS and OSU18. Several non-conserved amino acid replacements were identified, one of which occurs in the virulence-associated intracellular growth locus subunit D protein. Many of these changes in FTNF002-00 are likely the consequence of direct selection that increases the fitness of this subsp. holarctica clone within its endemic population. Our complete genome sequence analyses lay the foundation for experimental testing of these possibilities.

Genomic deletion marking an emerging subclone of Francisella tularensis subsp. holarctica in France and the Iberian Peninsula

Francisella tularensis subsp. holarctica is widely disseminated in North America and the boreal and temperate regions of the Eurasian continent. Comparative genomic analyses identified a 1.59-kb genomic deletion specific to F. tularensis subsp. holarctica isolates from Spain and France. Phylogenetic analysis of strains carrying this deletion by multiple-locus variable-number tandem repeat analysis showed that the strains comprise a highly related set of genotypes, implying that these strains were recently introduced or recently emerged by clonal expansion in France and the Iberian Peninsula.

Paired-end sequence mapping detects extensive genomic rearrangement and translocation during divergence of Francisella tularensis subsp. tularensis and Francisella tularensis subsp. holarctica populations

Comparative genome hybridization of the Francisella tularensis subsp. tularensis and F. tularensis subsp. holarctica populations have shown that genome content is highly conserved, with relatively few genes in the F. tularensis subsp. tularensis genome being absent in other F. tularensis subspecies. To determine if organization of the genome differs between global populations of F. tularensis subsp. tularensis and F. tularensis subsp. holarctica, we have used paired-end sequence mapping (PESM) to identify regions of the genome where synteny is broken. The PESM approach compares the physical distances between paired-end sequencing reads of a library of a wild-type reference F. tularensis subsp. holarctica strain to the predicted lengths between the reads based on map coordinates of two different F. tularensis genome sequences. A total of 17 different continuous regions were identified in the F. tularensis subsp. holarctica genome (CR(holar)(c)(tica)) which are noncontiguous in the F. tularensis subsp. tularensis genome. Six of the 17 different CR(holarctica) are positioned as adjacent pairs in the F. tularensis subsp. tularensis genome sequence but are translocated in F. tularensis subsp. holarctica, implying that their arrangements are ancestral in F. tularensis subsp. tularensis and derived in F. tularensis subsp. holarctica. PCR analysis of the CR(holarctica) in 88 additional F. tularensis subsp. tularensis and F. tularensis subsp. holarctica isolates showed that the arrangements of the CR(holarctica) are highly conserved, particularly in F. tularensis subsp. holarctica, consistent with the hypothesis that global populations of F. tularensis subsp. holarctica have recently experienced a periodic selection event or they have emerged from a recent clonal expansion. Two unique F. tularensis subsp. tularensis-like strains were also observed which likely are derived from evolutionary intermediates and may represent a new taxonomic unit.

Are paediatric burns more common in asylum seekers? An analysis of paediatric burn admissions

The number of asylum seekers in Ireland has increased dramatically over the last 10 years. Based on our impression that the number of children admitted to our burn unit was disproportionately represented by children of asylum seekers we performed an audit to establish (1) what proportion of admissions are from this subgroup and (2) the characteristics of their burns. All paediatric burn admissions from May 2003 to April 2004 were reviewed. Data collected from a retrospective chart review included patient demographics and details of the burn injuries. The National Census of 2002 and the Office of the Refugee Applications Commissioner were consulted for population statistics. Total burn admissions for the period were 126: Irish nationals (n=107), non-national residents (n=2), asylum seekers (n=14) and patients of unknown asylum status (n=3, excluded from study). In the asylum seeker group, the median age was 18.6 months (range 10 months-5.3 years) with the majority less than 2 years (n=11). All burns occurred in the domestic setting. Scalds accounted for 13 cases, one contact burn occurred from a hot grill. The median total body surface area burned was 5.7% (range 1.5-26%). The National Census of 2002 recorded a population of 3,917,203. With less than 12,000 asylum seekers in the country, they comprise only approximately 0.3% of the population yet they account for 11.4% of the burn patients admitted to our unit, p<0.0001. Children of asylum seekers are over-represented in our series of paediatric admissions for burns and are more likely than Irish children to sustain a burn at a younger age and in the domestic setting. This may indicate an increased risk of injury and warrants further investigation.

Detection of West Nile virus in mosquitoes by RT-PCR

A reverse transcriptase-polymerase chain reaction (RT-PCR) assay employing <<TaqMan>> detection technology was developed to identify West Nile virus in experimentally infected mosquitoes. The specificity of the assay was evaluated with the following viruses: eastern equine encephalitis, Ilheus, West Nile and yellow fever viruses. The limits of detection were determined using West Nile viral RNA extracted from serial dilutions of virus culture in infected mosquitoes. Limit of detection was 5 PFU from extracted mosquitoes. We were able to detect the presence of one infected mosquito in a pool of 50 repeatedly. When the RT-PCR was used with coded samples of intrathoracically-infected and uninfected mosquitoes, the assay detected the virus in all infected mosquitoes. Analytic sensitivity and specificity were 100%. This assay offers an efficient and rapid method of identifying West Nile virus in infected mosquitoes or cell culture.

Reduced nuclear import of human immunodeficiency virus type 1 preintegration complexes in the presence of a prototypic nuclear targeting signal

Nuclear import of the retroviral preintegration complex and integration of retroviral with host cell DNA are essential steps for completion of the virus life cycle. The preintegration complex of the lentivirus human immunodeficiency virus type 1 (HIV-1) displays karyophilic properties and, as a consequence, is rapidly directed to the host cell nucleus by an energy-dependent transport pathway. The karyophilic properties of nuclear proteins are governed by a nuclear localization sequence, the targeting function of which can be inhibited in the presence of excess targeting signals. Here we present evidence that the nuclear import of a large karyophile--the preintegration complex of HIV-1--is inhibited in the presence of a prototypic nuclear targeting signal of simian virus 40 T antigen. This points to a novel strategy which prevents establishment of the provirus by interrupting nuclear localization of HIV-1 DNA.

A nuclear localization signal within HIV-1 matrix protein that governs infection of non-dividing cells

Permissiveness of the host cell to productive infection by oncoretroviruses is cell-cycle dependent, and nuclear localization of viral nucleoprotein preintegration complexes will occur only after cells have passed through mitosis. In contrast, establishment of an integrated provirus after infection by the lentivirus HIV-1 is independent of host cell proliferation. The ability of HIV-1 to replicate in non-dividing cells is partly accounted for by the karyophilic properties of the viral preintegration complex which, after virus infection, is actively transported to the host cell nucleus. Here we report that the gag matrix protein of HIV-1 contains a nuclear localization sequence which, when conjugated to a heterologous protein, directs its nuclear import. In addition, HIV-1 mutants containing amino-acid substitutions in this nuclear localization signal integrate and replicate within dividing but not growth-arrested cells, and thus display a phenotype more representative of an oncoretrovirus.

Active nuclear import of human immunodeficiency virus type 1 preintegration complexes

After cell infection by the human immunodeficiency virus type 1 (HIV-1), nascent viral DNA in the form of a high molecular weight nucleoprotein preintegration complex must be transported to the nucleus of the host cell prior to integration of viral DNA with the host genome. The mechanism used by retroviruses for nuclear targeting of preintegration complexes and dependence on cell division has not been established. Our studies show that, after infection, the preintegration complex of HIV-1 was rapidly transported to the nucleus of the host cell by a process that required ATP but was independent of cell division. Functional HIV-1 integrase, an essential component of the preintegration complex, was not required for nuclear import of these complexes. The ability of HIV-1 to use host cell active transport processes for nuclear import of the viral preintegration complex obviates the requirement for host cell division in establishment of the integrated provirus. These findings are pertinent to our understanding of early events in the life cycle of HIV-1 and to the mode of HIV-1 replication in terminally differentiated nondividing cells such as macrophages (monocytes, tissue macrophages, follicular dendritic cells, and microglial cells).

Quiescent T lymphocytes as an inducible virus reservoir in HIV-1 infection

To better understand the basis for human immunodeficiency virus type 1 (HIV-1) persistence and latency, the form in which viral DNA exists in the peripheral T lymphocyte reservoir of infected individuals was investigated. In asymptomatic individuals, HIV-1 was harbored predominantly as full-length, unintegrated complementary DNA. These extrachromosomal DNA forms retained the ability to integrate upon T cell activation in vitro. In patients with acquired immunodeficiency syndrome (AIDS), there was an increase in integrated relative to extrachromosomal DNA forms. By analysis of DNA from patient lymphocyte subpopulations depleted of human lymphocyte antigen-Dr receptor-positive cells, quiescent T cells were identified as the source of extrachromosomal HIV-1 DNA. Thus quiescent T lymphocytes may be a major and inducible HIV-1 reservoir in infected individuals.

Posttranslational modifications within the HIV-1 envelope glycoprotein which restrict virus assembly and CD4-dependent infection

Alterations in two highly conserved N-linked glycosylation sites within the gp120 envelope glycoprotein of human immunodeficiency virus type I (HIV-1) implicated in the phenotype of a noncytopathic HIV-1 variant were introduced independently and in combination into a cytopathic, infectious HIV-1 clone by site-specific mutagenesis. Neither mutation affected the synthesis of HIV-1 envelope glycoproteins. However, one of the mutations restricted the ability of HIV-1 envelope to localize on the cell membrane and thus markedly impaired virus assembly. The HIV-1 assembly defect could be overcome in trans if site-specific mutants were packaged in HeLa cells constitutively producing wild-type HIV-1 envelope glycoprotein. In addition to inefficient virus assembly, this mutation impaired the ability of the virus to infect CD4+ T cells, but did not affect CD4-independent infection of muscle cells. These results suggest additional functions of posttranslational modification in virus replication (i.e., envelope glycoprotein transport). Given that such modifications can restrict CD4-mediated uptake without affecting CD4-independent uptake, variations in posttranslational env processing between different HIV-1 genotypes may affect virus tropism in vivo.

HIV-1 replication is controlled at the level of T cell activation and proviral integration

During progression of the Acquired Immune Deficiency Syndrome (AIDS), the human immunodeficiency virus type 1 (HIV-1) is harbored in CD4+ T cells, which act as the primary reservoir for the virus. In vitro, HIV-1 requires activated T cells for a productive infection; however, in vivo, the number of circulating T cells in the activated state that are potential targets for HIV-1 infection is low. We have investigated the ability of HIV-1 to infect resting T cells, and the consequences of such an infection. T cell activation was not required for HIV-1 infection; however, viral DNA was unable to integrate in resting T cells and was maintained extrachromosomally. Subsequent T cell activation allowed integration of extrachromosomal forms and led to a productive viral life cycle. Extrachromosomal forms of viral DNA were found to persist for several weeks after infection of resting T cells and, following T cell activation, these forms maintained their ability to integrate and act as a template for infectious virus. Several lines of evidence, including temporal analysis of HIV-1 replication and analysis of an HIV-1 integrase deletion mutant, indicated that extra-chromosomal HIV-1 DNA genomes were transcriptionally active. These results are compatible with a model whereby HIV-1 can persist in a non-productive extra-chromosomal state in resting T cells until subsequent antigen-induced or mitogen-induced T cell activation, virus integration and release. Thus agents that induce T cell activation may control the rate of HIV-1 replication and spread during AIDS progression.