Single Bacterial Infection Research Articles

A new protocol for multispecies bacterial infections in zebrafish and their monitoring through automated image analysis.

The zebrafish Danio rerio has become a popular model host to explore disease pathology caused by infectious agents. A main advantage is its transparency at an early age, which enables live imaging of infection dynamics. While multispecies infections are common in patients, the zebrafish model is rarely used to study them, although the model would be ideal for investigating pathogen-pathogen and pathogen-host interactions. This may be due to the absence of an established multispecies infection protocol for a defined organ and the lack of suitable image analysis pipelines for automated image processing. To address these issues, we developed a protocol for establishing and tracking single and multispecies bacterial infections in the inner ear structure (otic vesicle) of the zebrafish by imaging. Subsequently, we generated an image analysis pipeline that involved deep learning for the automated segmentation of the otic vesicle, and scripts for quantifying pathogen frequencies through fluorescence intensity measures. We used Pseudomonas aeruginosa, Acinetobacter baumannii, and Klebsiella pneumoniae, three of the difficult-to-treat ESKAPE pathogens, to show that our infection protocol and image analysis pipeline work both for single pathogens and pairwise pathogen combinations. Thus, our protocols provide a comprehensive toolbox for studying single and multispecies infections in real-time in zebrafish.

Post Caesarean Surgical Site Infection: Incidence, Prevalence, Risk Factors and Microbiological Profile of Tertiary Care Hospital, Jaipur

Background: In the past few decades, the prevalence of cesarean sections (CS) has continuously increased worldwide making it one of the most frequent surgical procedures. CS can often save a patient's life, but there are chances of postoperative consequences such as surgical site infections (SSI). During this study we have determine the occurrence and risk factors associated surgical site infections in women undergoing CS. Methodology: This is a prospective study conducted in a tertiary care hospital. Total 280 women were selected whose undergoes elective or emergency CS during May 2023 – July 2023. Each woman was properly examined and followed for 7 days to developed SSI. Bacterial profile and antibiotics pattern were examined to relate other factors associated with SSI. Results: Among 280 candidate 59 candidate suspected for SSI which are 4.74%. after microbiological analysis 5 samples were failed to produce culture, 54 (5.18%) samples were identified as SSI. Among 54 samples 77. 78% (n=42) observed as Single bacterial infection and 22.22 (n=12) observed as Mixed bacterial infection. Among all Coagulase negative staphylococci spp (CoNS) showed the highest infection 22.23% followed by Staphylococcus aureus 16.95% highest infection was observed in higher age candidate (>30) 37.04%, rural candidate 59.26%, obese candidate 31.48% and Lower-class candidate 53.70%. Conclusion: This study showed the high incidence of SSI after CS which highlighted the urgent need of prevent and surveillance of SSI. Considering patients demographic and medical history incidences of SSI can be reduced.

Comparative analysis of the application efficiency of gold nanoparticles-based SERS in four foodborne pathogenic microbes

It has been widely reported that SERS can detect foodborne pathogenic bacteria, but SERS has only been limited to the detection of purified single bacteria. However, there’s few single bacterial infections in the natural state were found at the most time, and rare comparative investigations of different Gram-negative and Gram-positive bacteria by SERS exist. At the present study, we are aiming at the comparative analysis of the detection efficiency toward different foodborne pathogenic microbes by a conventional citrate-reduced gold colloid, including Escherichia coli, Salmonella enteritidis, Staphylococcus aureus and Listeria monocytogenes. The SERS spectra of samples were collected with sterile 0.5% NaCl solution as aggregating compound. First, the stability of each bacterial were detected with gold nanoparticles. Afterward, SERS signals of the four bacteria were compared at different concentrations, and it was found that Gram-positive and Gram-negative bacteria have different minimum sensitivity and detection stability. Next, the mixed bacterial SERS detection was applied to classify and identify the similar Raman spectra. Spectral data were analyzed using multivariate data analysis methods, including principal component analysis (PCA) and hierarchical cluster analysis (HCA). The SERS procedure we proposed, which utilized gold nanoparticles adsorbing on bacteria and multivariate analysis, allowed differentiation of species. The results of this pilot study demonstrate the potential of SERS to rapidly identify Gram-negative and Gram-positive foodborne pathogens.

Multifunctional integration of tungsten oxide (WO3) coating: A versatile approach for enhanced performance of antibiotics against single mixed bacterial infections

Nanomaterials containing tungsten (TNMs), characterized by diverse nanostructures had been extensively used in biomedical sector. Despite numerous reports focusing on TNM applications in specific biomedical areas, there is a noticeable absence of comprehensive studies that focused on detailed characterization of nanomaterials along with their biological applications. The present work described the structural, morphological, and antimicrobial properties of tungsten oxide (WO3) nanoparticles coated by antibiotics (nanobiotics), and their application on single and mixed bacterial culture. The nanobiotics included in this study were WO3 coated with ampicillin (W+A), WO3 coated with penicillin (P+W), and WO3 coated with ciprofloxacin (C+W). Techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray spectroscopy (EDX), Fourier transforms infrared spectroscopy (FTIR), Rrman spectroscopy, and UV–visible spectroscopy were used to characterize synthesized nanoparticles. The minimum inhibitory concentration of C+W nanobiotic against S. aureus, E. coli, and mixed culture (S. aureus +E. coli) was lower than that of P+W and A+W. The impact of incubation period showed significant differences for each of nanobiotic against S. aureus, E. coli, and mixed culture. However, there were also non-significant differences among incubation periods for antibacterial activity of nanobiotics. It was pertinent to note that percentage variation in susceptibility of S. aureus with respect to mixed culture remained higher as compared to E. coli, indicating it stronger candidate imposing resistance. This paper thus suggested the strategy of coating of antibiotics with with WO3 nanoparticles as an ideal combination for resistance modulation against single and mixed culture bacteria.

Mycobacterium tuberculosis complex molecular networks and their regulation: Implications of strain heterogeneity on epigenetic diversity and transcriptome regulation

Tuberculosis has been a public health crisis since the 1900, which has caused the highest mortalities due to a single bacterial infection worldwide, that was recently further complicated by the Coronavirus disease 2019 pandemic. The causative agent of Tuberculosis, Mycobacterium tuberculosis, belongs to a genetically well-characterized family of strains known as the Mycobacterium tuberculosis complex, which has complicated progress made towards eradicating Tuberculosis due to pathogen-specific phenotypic differences in the members of this complex. Mycobacterium tuberculosis complex strains are genetically diverse human- and animal-adapted pathogens belonging to 7 lineages (Indo-Oceanic, East-Asian, East-African Indian, Euro-American, M. africanum West Africa 1, M. africanum West Africa 2 and Ethopia), respectively and the recently identified Lineage 8 and M. africanum Lineage 9. Genomic studies have revealed that Mycobacterium tuberculosis complex members are ∼99 % similar, however, due to selective pressure and adaptation to human host, they are prone to mutations that have resulted in development of drug resistance and phenotypic heterogeneity that impact strain virulence. Furthermore, members of the Mycobacterium tuberculosis complex have preferred geographic locations and possess unique phenotypic characteristics that is linked to their pathogenicity. Due to the recent advances in development next generation sequencing platforms, several studies have revealed epigenetic changes in genomic regions combined with “unique” gene regulatory mechanisms through non-coding RNAs that are responsible for strain-specific behaviour on in vitro and in vivo infection models. The current review provides up to date epigenetic patterns, gene regulation through non-coding RNAs, together with implications of these mechanisms in down-stream proteome and metabolome, which may be responsible for “unique” responses to infection by members of the Mycobacterium tuberculosis complex. Understanding lineage-specific molecular mechanisms during infection may provide novel drug targets and disease control measures towards World Health organization END-TB strategy.

Self-promoted electroactive biomimetic mineralized scaffolds for bacteria-infected bone regeneration

Infected bone defects are a major challenge in orthopedic treatment. Native bone tissue possesses an endogenous electroactive interface that induces stem cell differentiation and inhibits bacterial adhesion and activity. However, traditional bone substitutes have difficulty in reconstructing the electrical environment of bone. In this study, we develop a self-promoted electroactive mineralized scaffold (sp-EMS) that generates weak currents via spontaneous electrochemical reactions to activate voltage-gated Ca2+ channels, enhance adenosine triphosphate-induced actin remodeling, and ultimately achieve osteogenic differentiation of mesenchymal stem cells by activating the BMP2/Smad5 pathway. Furthermore, we show that the electroactive interface provided by the sp-EMS inhibits bacterial adhesion and activity via electrochemical products and concomitantly generated reactive oxygen species. We find that the osteogenic and antibacterial dual functions of the sp-EMS depend on its self-promoting electrical stimulation. We demonstrate that in vivo, the sp-EMS achieves complete or nearly complete in situ infected bone healing, from a rat calvarial defect model with single bacterial infection, to a rabbit open alveolar bone defect model and a beagle dog vertical bone defect model with the complex oral bacterial microenvironment. This translational study demonstrates that the electroactive bone graft presents a promising therapeutic platform for complex defect repair.

Distribution Patterns of Pathogens Causing Lower Respiratory Tract Infection Based on Metagenomic Next-Generation Sequencing.

Lower Respiratory Tract Infection (LRTI) is a leading cause of morbidity and mortality worldwide. In this study, the distribution patterns of causative pathogens in LRTI were evaluated within a city-level hospital by combining conventional microbiological tests (CMT) with metagenomic next-generation sequencing (mNGS). This retrospective cohort study involved 160 patients suspected of having LRTI in a single center. Specimens, including bronchoalveolar lavage fluid (BALF), blood, tissue, sputum, and pus were utilized to identify pathogens. The seasonal prevalence of pathogens and co-pathogens involved in multiple infections was analyzed. A total of 137 patients with 156 samples were included in this study. Pseudomonas aeruginosa, Corynebacterium striatum, Klebsiella pneumoniae, Candida, and human herpesvirus were the top prevalent pathogens. We observed seasonal dynamic variation in the top prevalent bacteria (Pseudomonas aeruginosa and Klebsiella pneumoniae) and herpesvirus (Epstein-Barr virus and Human herpesvirus-7). The majority of patients had single bacterial infections, followed by instances of bacterial-viral co-infections, as well as mixed infections involving bacteria, fungi, and viruses. Notably, the spectrum of co-infecting pathogens was broader among the elderly population, and positive Spearman correlations were observed among these co-infecting pathogens. Co-infections were prevalent among patients with LRTI, and the pathogens displayed distinct seasonal distribution patterns. The findings underscored the significance of comprehending pathogen distribution and epidemic patterns, which can serve as a basis for early etiological identification.

Etiological and clinical characteristics of severe pneumonia in pediatric intensive care unit (PICU)

ObjectiveTo analyze the etiological distribution characteristics of pediatric patients with severe pneumonia admitted to the Pediatric Intensive Care Unit (PICU), in order to provide a reference for the rational use of clinical antimicrobial drugs.MethodsA retrospective analysis of pediatric patients admitted to PICU with a diagnosis of severe pneumonia from January 2018 to December 2021 was performed and statistical analysis of pathogenic characteristics was performed.ResultsA total of 649 pathogens were detected in 515 children, with a positive detection rate of 77.48%. Bacteria were detected at the highest rate (40.52%), followed by viruses (34.35%), atypical pathogens (19.72%) and fungal (4.31%). Gram-positive infections were dominated by Staphylococcus aureus (39.56%) and Streptococcus pneumoniae (32.97%), and Gram-negative infections were dominated by Acinetobacter Bahmani (16.28%) and Haemophilus influenzae (15.12%), followed by Klebsiella pneumoniae (13.95%) and Pseudomonas aeruginosa (12.21%). Viral infections were dominated by respiratory syncytial virus (25.65%) and EB virus (20.43%), fungal infections were dominated by Candida albicans (50.0%). The proportion of children infected with single pathogen (49.62%) was comparable to that of those with mixed infections (50.38%). There were statistically significant differences in the distribution of children with single pathogen infection by gender (P < 0.05). The age distribution of children with single bacterial, single viral and single fungal infections was statistically different (P < 0.05). There was no significant difference in the distribution of onset season in children with single pathogen infections (P > 0.05), but the number of children with single viral infections was significantly higher in winter and spring than that in summer and autumn, and the difference was statistically significant (P < 0.05). A mixture of 2 pathogens (77.61%) accounted for the majority of mixed infections, there were statistical differences in the distribution of bacterial + viral infection in terms of gender, age, and onset season (P < 0.05), children with viral + mycoplasma infection in terms of gender and age (P < 0.05), and children with viral + fungal infection in terms of gender (P < 0.05), and children with bacterial + mycoplasma infection in terms of age and onset season (P < 0.05). Among the children infected with 3 pathogens, there were statistically significant differences in the distribution of bacterial + viral + fungal and viral + mycoplasma + fungal infections in terms of gender (P < 0.05), and children with bacterial + viral + mycoplasma infection in terms of age (P < 0.05), while there was no significant difference in the distribution of onset season (P > 0.05). There were no significant differences in the distribution of children infected with 4 pathogens in terms of gender, age and onset season (P > 0.05).ConclusionThe pathogens of pediatric patients with severe pneumonia in PICU commonly involves bacteria and viruses. As the age of children grows, the detection rate of bacteria shows a decreasing trend, and the pathogenic spectrum gradually changes from bacteria to mycoplasma and viruses, and the number of mixed infections gradually increase. Rational selection of antimicrobial drugs needs to consider pathogenic characteristics of different age, gender, and onset season in clinical practice.

The Role of IL-6 and IL-17 in SARS CoV-2 Patients with Secondary Bacterial Pneumonia

The current study was conducted in Kirkuk city at Al-Shifaa 14 hospital from November 2021 to March 2022, indicated the bacteria causing secondary pneumonia isolated from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) patients and the role of IL-6 and IL-17 in these infection.&#x0D; Sputum samples were used to obtain the bacterial isolates, and API testing was used to confirm the species level identification. Using an enzyme-linked immunosorbent assay (sandwich ELISA), the levels of IL-6 and IL-17 in the blood were evaluated. The study documented several bacterial species in a single infection (56/87.5%) or mixed bacterial infection (8/12.5%). The most common isolated bacteria species was Klebsiella pneumoniae (35.95%) followed by Staphylococcus aureus (31.25%), E. coli (17.19%), Pseudomonas aeruginosa (10.94%), and (1.56%) for each of Klebsiella oxytoca, Acinetobacter baumannii and Cronobacter sakazakii. The study recorded a high significant difference (P &lt;0.01) between the patients (22.2±6.82) pg/mL and the control group (58.39±11.15) pg/ mL concerning IL-6 also a high significant difference (P &lt;0.01) between the patients (101.79±27.13) pg/mL and the control group (58.39±11.15) pg/mL concerning IL-17.&#x0D; In conclusion, K. pneumoniae and S. aureus were the predominant isolated bacteria from COVID-19 patient's lung and there was a highly significant increase in IL-6 and IL-17 levels in secondary bacterial pneumonia in COVID-19 patients.

Evaluation of InTray Cassettes Directly from Blood Cultures for the Diagnosis of Sepsis in Clinical Bacteriology Laboratories as an Alternative to Classic Culture Media.

Culture media is fundamental in clinical bacteriology for the detection and isolation of bacterial pathogens. However, in-house media preparation could be challenging in low-resource settings. InTray® cassettes (Biomed Diagnostics) could be a valid alternative as they are compact, ready-to-use media preparations. In this study, we evaluate the use of two InTray media as a subculture alternative for the diagnosis of bloodstream infections: the InTray® Müller-Hinton (MH) chocolate and the InTray® Colorex™ Screen. The InTray MH chocolate was evaluated in 2 steps: firstly, using simulated positive blood cultures (reference evaluation study), and secondly, using positive blood cultures from a routine clinical laboratory (clinical evaluation study). The Colorex Screen was tested using simulated poly-microbial blood cultures. The sensitivity and specificity of the InTray MH chocolate were respectively 99.2% and 90% in the reference evaluation study and 97.1% and 88.2% in the clinical evaluation study. The time to detection (TTD) was ≤20 h in most positive blood cultures (99.8% and 97% in the two studies, respectively). The InTray® MH Chocolate agar showed good performance when used directly from clinical blood cultures for single bacterial infections. However, mixed flora is more challenging to interpret on this media than on Colorex™ Screen, even for an experienced microbiologist.

Mutual Effects of Single and Combined CFTR Modulators and Bacterial Infection in Cystic Fibrosis.

Cystic fibrosis transmembrane conductance regulator (CFTR) modulators improve clinical outcomes with varied efficacies in patients with CF. However, the mutual effects of CFTR modulators and bacterial adaptation, together with antibiotic regimens, can influence clinical outcomes. We evaluated the effects of ivacaftor (IVA), lumacaftor (LUM), tezacaftor, elexacaftor, and a three-modulator combination of elexacaftor, tezacaftor, and ivacaftor (ETI), alone or combined with antibiotics, on sequential CF isolates. IVA and ETI showed direct antimicrobial activities against Staphylococcus aureus but not against Pseudomonas aeruginosa. Additive effects or synergies were observed between the CFTR modulators and antibiotics against both species, independently of adaptation to the CF lung. IVA and LUM were the most effective in potentiating antibiotic activity against S. aureus, while IVA and ETI enhanced mainly polymyxin activity against P. aeruginosa. Next, we evaluated the effect of P. aeruginosa pneumonia on the pharmacokinetics of IVA in mice. IVA and its metabolites in plasma, lung, and epithelial lining fluid were increased by P. aeruginosa infection. Thus, CFTR modulators can have direct antimicrobial properties and/or enhance antibiotic activity against initial and adapted S. aureus and P. aeruginosa isolates. Furthermore, bacterial infection impacts airway exposure to IVA, potentially affecting its efficacy. Our findings suggest optimizing host- and pathogen-directed therapies to improve efficacy for personalized treatment. IMPORTANCE CFTR modulators have been developed to correct and/or enhance CFTR activity in patients with specific cystic fibrosis (CF) genotypes. However, it is of great importance to identify potential off-targets of these novel therapies to understand how they affect lung physiology in CF. Since bacterial infections are one of the hallmarks of CF lung disease, the effects (if any) of CFTR modulators on bacteria could impact their efficacy. This work highlights a mutual interaction between CFTR modulators and opportunistic bacterial infections; in particular, it shows that (i) CFTR modulators have an antibacterial activity per se and influence antibiotic efficacy, and (ii) bacterial airway infections affect levels of CFTR modulators in the airways. These findings may help optimize host- and pathogen-directed drug regimens to improve the efficacy of personalized treatment.

Initial blood cultures in pediatric patients with central line infections and short bowel syndrome can direct a treatment plan that can reduce hospital length of stay

BackgroundChildren with short bowel syndrome requiring parenteral nutrition are at high risk of recurrent central line–associated bloodstream infections requiring inpatient admission. Predicting responses to treatment at admission could help revise our current treatment algorithm and reduce the length of stay. MethodsWe conducted a retrospective study of all intestinal rehabilitation clinic patients admitted for central line–associated bloodstream infections at our academic hospital between January 2018 and June 2021. Demographic, blood culture, and treatment response data were analyzed. ResultsThere were 180 separate admissions for central line–associated bloodstream infections, involving 24 patients who met the inclusion and exclusion criteria. The average length of stay was 9.4 days, and 77.1% of the admissions exceeded the predicted length of stay. All patients were treated according to the standard protocols. In the initial blood cultures, 64.4%, 10.6%, and 25% grew a single bacterium, a single fungus, and multiple organisms, respectively. After treatment initiation, 73.3% of single bacterial infections did not show additional positive cultures. However, 78.9% and 48.9% of fungal and multiple organism infections, respectively, had multiple positive cultures, even after initiating treatment. All positive repeat cultures were treated with an ethanol lock for 24 hours in addition to continued treatment. The treatment preserved 90.5% of the catheters. ConclusionPatients experiencing short bowel syndrome admitted for central line–associated bloodstream infections with initial cultures growing fungi or multiple organisms frequently had multiple positive cultures, whereas those with a single bacterial organism did not. Discharging patients who grew a single bacterial organism and placing an initial ethanol lock on those with multiple or fungal organisms could reduce the average length of stay, even if some of these patients would require readmission for line removal.

Metagenomic next-generation sequencing for accurate diagnosis and management of lower respiratory tract infections

ObjectivesThis study aimed to evaluate the clinical value of metagenomic next-generation sequencing (mNGS) in patients with suspected lower respiratory tract infections. MethodsThis retrospective study reviewed patients with suspected lower respiratory tract infections at the Wuhan Union Hospital. Data including demographic, laboratory, and radiological profiles; treatment; and outcomes were recorded and analyzed. ResultsmNGS identified pathogenic microbes in 100/140 (71.4%) patients, although 135 (96.4%) had received empiric antibiotic treatment before the mNGS tests. Single bacterial infection (35/100, 35%) was the most common type of infection in patients with positive mNGS results, followed by single fungal infection (14/100, 14%), bacterial-viral coinfection (14/100, 14%), single viral infection (12/100, 12%), bacterial-fungal coinfection (9/100, 9%), fungal-viral coinfection (9/100, 9%), and bacterial-fungal-viral coinfection (7/100, 7%). Moreover, compared with culture test, mNGS showed higher sensitivity (63/85, 74.1% vs 22/85, 25.9% P = 0.001) and lower processing time (24 hours vs 48 hours). Antibiotic treatment was adjusted or confirmed based on the mNGS results in 123 (87.9%) patients, including five (3.6%), 33 (23.6%), and 85 (60.7%) patients, in whom treatment was downgraded, upgraded, and unchanged, respectively. Almost all patients, regardless of escalation, de-escalation, or no change in treatment, showed significant improvement in clinical symptoms and inflammatory indicators. In addition, 17 (12.1%) patients were referred to Wuhan Pulmonary Hospital for further treatment because of confirmed or suspected tuberculosis. ConclusionmNGS could be a promising technique for microbiological diagnosis and antibiotic management, potentially improving outcomes for patients.

Clinical evaluation of metagenomic next-generation sequencing for detecting pathogens in bronchoalveolar lavage fluid collected from children with community-acquired pneumonia.

This study is to evaluate the usefulness of pathogen detection using metagenomic next-generation sequencing (mNGS) on bronchoalveolar lavage fluid (BALF) specimens from children with community-acquired pneumonia (CAP). We retrospectively collected BALF specimens from 121 children with CAP at Tianjin Children's Hospital from February 2021 to December 2021. The diagnostic performances of mNGS and conventional tests (CT) (culture and targeted polymerase chain reaction tests) were compared, using composite diagnosis as the reference standard. The results of mNGS and CT were compared based on pathogenic and non-pathogenic organisms. Pathogen profiles and co-infections between the mild CAP and severe CAP groups were also analyzed. The overall positive coincidence rate was 86.78% (105/121) for mNGS and 66.94% (81/121) for CT. The proportion of patients diagnosed using mNGS plus CT increased to 99.18%. Among the patients, 17.36% were confirmed only by mNGS; Streptococcus pneumoniae accounted for 52.38% and 23.8% of the patients were co-infected. Moreover, Bordetella pertussis and Human bocavirus (HBoV) were detected only using mNGS. Mycoplasma pneumoniae, which was identified in 89 (73.55%) of 121 children with CAP, was the most frequent pathogen detected using mNGS. The infection rate of M. pneumoniae in the severe CAP group was significantly higher than that in the mild CAP group (P = 0.007). The symptoms of single bacterial infections (except for mycoplasma) were milder than those of mycoplasma infections. mNGS identified more bacterial infections when compared to the CT methods and was able to identify co-infections which were initially missed on CT. Additionally, it was able to identify pathogens that were beyond the scope of the CT methods. The mNGS method is a powerful supplement to clinical diagnostic tools in respiratory infections, as it can increase the precision of diagnosis and guide the use of antibiotics.

P006 MICROBIOLOGY OF CHRONIC MESH INFECTION

Abstract Aim Mesh infection represents a significant concern due to its terrible consequences. Mesh sinus, infected seromas, mesh extrusion, and mesh-related enteric fistulas are common complications associated with synthetic mesh. This study aimed to review the microbiota of mesh infection in a series of 100 patients submitted to mesh explantation. Material and Methods We reviewed the charts of patients presenting with a history of mesh infection lasting six months or more after mesh placement. All patients submitted to further abdominal wall repair with complete removal of the infected mesh and presenting a positive culture were included. The microbiota analysis was based on positive cultures obtained from the fluids and tissues surrounding the mesh or a positive culture of the mesh itself. Microorganisms were divided into gram-positive or gram-negative, aerobic or anaerobic, and fungi. Results Pure aerobic gram-positive cultures were encountered in 50% of the patients, followed by a combination of aerobic gram-positive/gram-negative (9%) and pure gram-negative cultures (6%). Anaerobes were recovered from 31% of patients. Fungi were recovered from 6%. Staphylococcus aureus was identified in 64% of cultures, with methicillin-resistant Staphylococcus aureus present in 42% and methicillin-sensitive Staphylococcus aureus in 22%. Among aerobic gram-negative infections, six (17%) were caused by multi-resistant bacteria, including Pseudomonas aeruginosa, Proteus mirabilis, Acinetobacter baumanii, Klebsiella pneumoniae complex, and Enterobacter cloacae complex. Conclusions Pure Staphylococcus aureus infections, occurring in 29%, accounted for most single bacterial infections. Gram-negative infections and anaerobes were commonly encountered in polymicrobial infections. Most fungi cultures occurred in patients with enteric fistulas.

Efficacy, Safety and Tolerability of a New 10% Intravenous Immunoglobulin for the Treatment of Primary Immunodeficiencies

We report here the results of a phase 3 study to assess the efficacy, safety, and tolerability of GC5107, a new 10% liquid intravenous immunoglobulin (IVIG) in preventing serious bacterial infections in patients with primary immunodeficiency (ClinicalTrials.gov: NCT02783482). Over a 12-month study period, 49 patients aged 3 to 70 years with a confirmed diagnosis of primary immunodeficiency received GC5107 at doses ranging from 319 to 881 mg/kg body weight every 21 or 28 days, according to their previous IVIG maintenance therapy. A total of 667 infusions of GC5107 were administered comprising a total of 45.86 patient-years of treatment. A single acute serious bacterial infection occurred during the study, resulting in an incidence of 0.02 events per patient-year (upper 99% one-sided confidence interval limit: 0.21), meeting the prespecified primary efficacy endpoint. The mean incidence of infections other than acute serious bacterial infections was 2.9 infections per patient-year. Efficacy was also demonstrated by the low mean annualized rate of hospitalizations due to infection (0.1 day) and the mean annualized duration of hospitalizations (0.1 day). The mean rate of intravenous and oral antibiotic use was 0.1 day and 13.2 days, respectively. There was a mean of 7.1 days of missed work, school, or daycare days. The proportion of infusions with temporally associated adverse events (TAAEs) occurring during or within 72 hours after GC5107 infusion was 0.24 (upper 95% one-sided confidence interval limit: 0.31), meeting the pre-specified primary safety endpoint. Overall, 149 of 667 infusions (22%) were associated with TAAEs. The most common TAAE was headache, reported by 49% of patients. More than 98% (731/743) of all adverse events that occurred throughout the 12-month study period were mild or moderate. More than 98% of infusions were completed without discontinuation, interruption or rate reduction. There were no treatment-emergent serious adverse events related to GC5107 or study discontinuations due to an adverse event. Overall, pharmacokinetic parameters for GC5107 were within the range of those reported in studies of other marketed IVIG products. Results of the present study demonstrate that GC5107 is an effective, safe and well-tolerated treatment for patients with primary immunodeficiency.

Value of procalcitonin and critical illness score in etiological diagnosis and prognosis of sepsis caused by intra-abdominal infections

To compare the early and late predictive values of critical illness score (CIS) and procalcitonin (PCT) in septic patients with blood stream infection (BSI) induced by intra-abdominal infection (IAI), and to identify the value of PCT in etiological diagnosis. The clinical data of patients with at least one positive blood culture within 24 hours admission to the emergency department of China-Japan Friendship Hospital from January 2014 to December 2019 and with final diagnosis of IAI induced sepsis were enrolled. Sequential organ failure assessment (SOFA), mortality in emergency department sepsis (MEDS), Logistic organ dysfunction system (LODS), and acute physiology and chronic health evaluation II (APACHE II) scores were calculated based on the parameters on the day of admission. Differences in various indicators among different Gram-stained bacterial infections and among patients with different prognosis at 28 days or 60 days were compared. Receiver operator characteristic curve (ROC curve) was used to analyze the value of PCT in differential etiological diagnosis of IAI induced sepsis caused by single bacterial infection, and the predictive value of CIS and PCT on 28-day and 60-day death of septic patients with BSI induced by IAI. A total of 221 septic patients with IAI caused by single bacterial infection were enrolled. The 28-day mortality was 19.9% (44/221), and the 60-day mortality was 25.8% (57/221). Mortality caused by Gram-positive (G+) bacterial infection of patients was significantly higher than that caused by Gram-negative (G-) bacterial infection (28 days: 34.6% vs. 11.4%, 60 days: 42.0% vs. 16.4%, both P < 0.01). Compared with patients with G+ bacterial infection, the PCT value of patients with G- bacterial infection was higher [μg/L: 4.31 (0.71, 25.71) vs. 1.29 (0.32, 10.83), P < 0.05]. Compared with survival group, the values of CIS and PCT in death group were higher, either in 28 days or in 60 days [death group vs. survival group in 28 days: SOFA score was 6.0 (4.0, 10.0) vs. 3.0 (2.0, 5.0), MEDS score: 11 (9, 14) vs. 6 (6, 9), LODS score: 4.0 (2.0, 6.0) vs. 1.0 (0, 2.0), APACHE II score: 17.0 (15.0, 24.0) vs. 12.0 (8.0, 15.0), PCT (μg/L): 3.48 (1.01, 26.70) vs. 2.45 (0.32, 15.65); death group vs. survival group in 60 days: SOFA score: 6.0 (4.0, 10.0) vs. 3.0 (2.0, 5.0), MEDS score: 9 (6, 14) vs. 6 (6, 9), LODS score: 4.0 (1.0, 5.0) vs. 1.0 (0, 2.0), APACHE II score: 16.5 (12.0, 20.0) vs. 12.0 (8.0, 15.0), PCT (μg/L): 2.67 (0.98, 17.73) vs. 2.22 (0.31, 16.75); all P < 0.05]. ROC curve showed that: (1) the area under ROC curve (AUC) of PCT in the diagnosis of IAI induced sepsis with single bacterial infection was 0.740 [95% confidence interval (95%CI) was 0.648-0.833]. When the optimal cut-off value of PCT was 1.82 μg/L, the sensitivity of diagnosis of G- bacterial infection was 74.0%, and the specificity was 68.2%. When PCT value was higher than 10.92 μg/L, the specificity of diagnosis of G- bacterial infection could reach 81.8%. (2) In the prediction of 28-day and 60-day mortality for septic patients with BSI induced by IAI, the APACHE II score achieved the highest AUC [28 days: 0.791 (95%CI was 0.680-0.902), 60 days: 0.748 (95%CI was 0.645-0.851)]. APACHE II score higher than 14.5 could help to predict 28-day and 60-day mortality for IAI patients with negative predictive values of 94.9% and 88.5%. However, the predictive value of PCT for septic patients with BSI induced by IAI was relatively lower [28-day AUC: 0.610 (95%CI was 0.495-0.725), 60-day AUC: 0.558 (95%CI was 0.450-0.667)]. PCT is more reliable in the identification of pathogen type among IAI induced sepsis with BSI, while APACHE II score may perform better in predicting early and late mortality.

Modified induced membrane technique and pedicled skin (myocutaneous) flap for chronic tibial osteomyelitis in patients with diabetes

To investigate the effectiveness of modified induced membrane technique and pedicled skin (myocutaneous) flap for chronic tibial osteomyelitis in patients with diabetes. A clinical data of 22 diabetic patients with chronic tibial osteomyelitis between January 2017 and March 2019 was retrospectively analyzed. There were 15 males and 7 females with an average age of 52 years (range, 44-65 years). The course of diabetes was 3-12 years (mean, 6.1 years). The course of chronic osteomyelitis was 4 months to 7 years (mean, 3.3 years). The chronic osteomyelitis was rated as type Ⅲ in 9 cases and as type Ⅳ in 13 cases according to the Cierny-Mader classification criteria. Bacterial culture showed 21 cases of single bacterial infection and 1 case of mixed bacterial infection. Preoperative color Doppler ultrasound and CT angiography confirmed that the anterior and posterior tibial arteries were unobstructed. In the first stage of treatment, the bone and soft tissue defects were filled with antibiotic bone cement after the lesion was thoroughly debrided; the length of bone defect was 4-9 cm (mean, 5.6 cm), and the size of soft tissue defect was 5 cm×2 cm to 10 cm×7 cm. After 7-10 days, the bone cement was removed and a new antibiotic bone cement was filled into the bone defect. Meanwhile, the pedicled skin (myocutaneous) flap was performed to repair the wound. After 7-12 weeks, the inflammatory indexes returned to normal, autogenous iliac bone or combined with artificial bone was used to repair the bone defect in the second stage of treatment. The wound healing, bone defect healing, complications, and the number of successful treatments were recorded. The satisfaction of the skin flap efficacy and the function of the affected limb were evaluated. Local necrosis of the skin flap occurred in 3 cases after operation, leading to delayed healing of the wound; the other 19 flaps survived successfully, leading to primary healing of the wound. The skin grafts survived completely and the incisions healed by first intention. All cases were followed up 13-28 months with an average of 20 months. The infection recurred in 2 cases within 12 months after operation, and the bone defects healed after treated by modified induced membrane technique. The bone defect healing rate was 100%; the bone healing time was 6-10 months, with an average of 8.9 months; the infection control rate and successful treatment rate were 90.9% (20/22) and 90.9% (20/22), respectively. At 12 months after operation, according to the satisfaction evaluation standard of skin flap efficacy formulated by ZHANG Hao et al., all were satisfied. According to Johner-Wruhs adjacent joint function method, the limb function recovery was excellent in 13 cases, good in 7 cases, and fair in 2 cases, with an excellent and good rate of 90.9%. For the treatment of chronic tibial osteomyelitis in patients with diabetes without vascular occlusion, the modified induced membrane technique and pedicled skin (myocutaneous) flap can repair bone and soft tissue defects, and control the infection at the same time, the short- and medium-term effectiveness are good.

MO976GENDER AND AGE DISPARITY IN INFECTIOUS COMPLICATIONS AFTER KIDNEY TRANSPLANTATION

Abstract Background and Aims Number of older patients with end stage kidney disease has been increasing, therefore there are increased number of older kidney transplant recipients. Potent immunosuppression (IS) used in patients after kidney transplantation (KTx) lowered the incidence of acute kidney rejection but increased the risk of post-transplant infection and sepsis as the most common non-cardiac cause of death. Older adults are at high risk of infections due to functional impairment and multiple comorbidities leading to poor outcome after KTx. Nowadays, no change in IS or prophylactic therapy is recommended based on the age of an adult KTx recipient. Female gender may be risk factor for infection after KTx due immunomodulatory effect of sex hormones such as estradiol. Methods The aim of our analysis was to find whether there are sex differences in the incidence of single and repeat infection and whether there is increased incidence of single and recurrent infectious complications in older kidney transplant recipients. Results Our analysis consisted of 100 patients after KTx (66 males, 34 females), average age 47,5 ± 12,6 years, treated with anti-thymocyte globulin as an induction IS. Male gender was a protective factor for the incidence of following infections in the 1st month after KTx: infection in general (P = 0.0054), recurrent infection (P = 0.0239), bacterial (P = 0.0125) and mycotic infection (P = 0.0103), recurrent bacterial infection (P = 0.0258). From the 1st to 6th month after KTx, female gender was identified as a risk factor for the incidence of infection in general (P = 0.0218), bacterial (P = 0.0186) and mycotic infection (P = 0.0318), repeat infection (P = 0.0216), recurrent bacterial infection (P = 0.0368). From 6th to 12th month after KTx, female gender was found as a risk factor for the incidence of bacterial infection (P = 0.0144), single infection (P = 0.0355), recurrent infection (P = 0.0007), single bacterial infection (P = 0.0309). Age &amp;gt; 60 years was not found as a risk factor for the incidence of single, repeat infection regarding its etiology. In our analysis we did not found correlation between gender and the incidence of single or recurrent infection of any etiology, we did not find significant differences in the severity of infections reflected by need for hospitalization, intensive care unit or use of vasopressors neither in gender, nor in older patients. In our study we did not confirm gender or age as a risk factor for the acute kidney rejection. Conclusion In our analysis, we found significant sex differences in the incidence of bacterial, viral, mycotic, single and repeat infection in different time intervals after kidney transplantation, while we did not confirmed age &amp;gt; 60 years is a risk factor for the infectious complications after KTx.

Co-infection of H9N2 Influenza A Virus and Escherichia coli in a BALB/c Mouse Model Aggravates Lung Injury by Synergistic Effects.

Pathogens that cause respiratory diseases in poultry are highly diversified, and co-infections with multiple pathogens are prevalent. The H9N2 strain of avian influenza virus (AIV) and Escherichia coli (E. coli) are common poultry pathogens that limit the development of the poultry industry. This study aimed to clarify the interaction between these two pathogens and their pathogenic mechanism using a mouse model. Co-infection with H9N2 AIV and E. coli significantly increased the mortality rate of mice compared to single viral or bacterial infections. It also led to the development of more severe lung lesions compared to single viral or bacterial infections. Co-infection further causes a storm of cytokines, which aggravates the host’s disease by dysregulating the JAK/STAT/SOCS and ERK1/2 pathways. Moreover, co-infection mutually benefited the virus and the bacteria by increasing their pathogen loads. Importantly, nitric oxide synthase 2 (NOS2) expression was also significantly enhanced by the co-infection. It played a key role in the rapid proliferation of E. coli in the presence of the co-infecting H9N2 virus. Therefore, our study underscores the role of NOS2 as a determinant for bacteria growth and illustrates its importance as an additional mechanism that enhances influenza virus-bacteria synergy. It further provides a scientific basis for investigating the synergistic infection mechanism between viruses and bacteria.