Common Source Of Infection Research Articles

187. Risk Factors and Outcomes of Patients with Serratia Bacteremia at an Academic Medical Center

Abstract Background The majority of reported Serratia infective endocarditis (SIE) in recent years are healthcare-associated. At our urban institution with a high prevalence of people who inject drugs (PWID), we noted an increasing number of Serratia bacteremias (SB) and SIE over the past decade. Our study describes patient factors associated with SB and SIE. Methods We evaluated charts of patients with SB at our institution between 2010 and 2022 to determine risk factors and clinical outcomes. Results There were 157 episodes of SB in 153 patients. The majority were male (57%), white (57%) with a mean age 53. The most common source of infection was catheter- line-associated infection (CLABSI) (27%), followed by primary bacteremia (19%). Twenty-six % were PWID with younger mean age (41 years). PWID had lower mortality than non-PWID (23% vs 44%, p=0.023). Sixty-nine (46%) were admitted to the intensive care unit (ICU) with significantly higher mortality associated with ICU admission (48% vs 8%, p=0.015). Echocardiograms were performed in 59% (93/157) of SB episodes and 14% had SIE (13/93). Most SIE (69%) occurred after 2017 with 89% in PWID (8/9). The most common comorbidity with SIE was injection drug use (IDU) (69%). All non-IDU SIE were CLABSI-related; 75% had hemodialysis catheters. Tricuspid valves were infected in 46%. Sixty-two % of those with SIE had septic emboli. Most SIE (69%) required ICU admission. Overall mortality was 31%. Only 2% (3/153) of patients with SB developed antibiotic resistance on therapy. Clinical worsening or failure occurred in 20% (32/157). Only 5% (7/157) had microbiologic recurrence within 30 days. 32% of discharged patients re-presented to the hospital within 30 days. Almost all deaths (92%) occurred during initial admission. Conclusion Patients with SB were quite ill with a high rate of in-hospital mortality; over half of the patients had antibiotic exposures prior to developing SB or presented within 90 days of a prior hospitalization. The majority of SB were line-associated, including all episodes of non-IDU SIE. IDU was the second most common comorbidity and PWID with SB had a higher rate of SIE, with most IDU-associated SIE diagnosed after 2017. This aligns with other recent studies documenting the increased prevalence of SB, especially in PWID. Disclosures Madeline King, PharmD, La Jolla: Advisor/Consultant|Shionogi: Advisor/Consultant

2779. Early Administration of Ceftazidime-Avibactam for Carbapenem-Resistant Enterobacterales Is Associated with Improved Clinical Success

Abstract Background Carbapenem-resistant Enterobacterales (CRE) are a significant public health threat. Ceftazidime-avibactam (CZA) retains activity against most carbapenemase-producing CRE and demonstrates favorable health outcomes compared to historically best available therapy. While early initiation of effective therapy is critical in serious infections, the impact of time to CZA initiation on CRE infection-related outcomes has yet to be assessed. Aim: to evaluate clinical outcomes of patients with CRE infections receiving early vs. late CZA as the first active β-lactam. Methods Multicenter, retrospective cohort of hospitalized adult patients from 2019-2022 with culture-positive CRE and infectious symptoms receiving early vs. late CZA as the first active β-lactam. Early and late CZA were defined as CZA administration within or after 48 hours of index culture collection, respectively. Primary outcome was a composite of clinical success defined as i) the absence of all-cause mortality or microbiological recurrence requiring therapy within 30 days from the end of CZA therapy and ii) continued infectious symptoms during CZA therapy. Results In total, 174 patients were included (≤48 hours n=52, >48 hours n=122). Median (IQR) age was 61 (53, 73) years and 56.3% were male. ICU admission rates were similar between early vs. late CZA (73.1% vs. 72.1%; P=0.921). Most common infection sources were respiratory (59.8%) and skin and skin structure (9.2%). Klebsiella pneumoniae was the most common CRE isolated (66%). The overall median (IQR) of CZA MIC was 2 (1,4). and there was no difference in the receipt of package insert CZA doses in the first 48 hours of CZA therapy between the early vs. late groups, respectively (1.9% vs. 5.2%; P=0.311). In total, 40/52 (76.9%) early and 68/122 (55.7%) late CZA patients met the clinical endpoint of clinical success (P< 0.001). The early and late CZA groups demonstrated similar ICU length of stay (LOS) (26 [9, 46] vs. 22 [12, 40]; P=0.431, respectively). Table 1. Baseline and Clinical Characteristics Conclusion In hospitalized adult patients with CRE infections, CZA administration within 48 hours of culture collection was associated with a higher rate of clinical success compared to CZA administered after 48 hours. Further studies in a larger patient cohort are warranted to verify these results. Disclosures Wesley D. Kufel, Pharm.D., BCPS, BCIDP, AAHIVP, Merck: Grant/Research Support Bryan White, PharmD, BCPS, BCIDP, Gilead Sciences: Advisor/Consultant Michael J. Rybak, PharmD, PhD, MPH, Abbvie, Merck, Paratek, Shionogi, Entasis, La Jolla, T2 Biosystems: Advisor/Consultant

2118. Comparative Analysis of Cefiderocol Mono- and Combination Therapy for Multi-Drug Resistant Gram-negative Infections

Abstract Background Multi-drug resistant gram-negative infections are a growing concern, necessitating the development of novel treatments. Cefiderocol (CFDC) is a new siderophore cephalosporin that targets the iron transport mechanism used by many gram-negative pathogens. We aimed to compare the clinical outcomes of CFDC monotherapy and combination therapy in various infection types. Methods We performed a retrospective cohort analysis at 5 academic medical centers from May 2022 to April 2023. Patients were included if they were ≥18 years old and received CFDC for ≥48 hours, excluding subsequent courses not separated by ≥90 days. The primary objective was composite clinical success (30-day survival, absence of 30-day infection recurrence and resolution of signs and symptoms), with secondary objectives including individual components of clinical success, on-treatment resistance, 30-day readmission, and adverse reactions. Descriptive statistics and logistic regression were used. Results We analyzed 70 patients, with 35 in each treatment group. The cohort was predominantly male (64.3%), had a mean age of 55.5 years (17.6), and 67% were admitted to the Intensive Care Unit. The mean (SD) APACHE II scores were 12.8 (7.5) for monotherapy and 14.9 (6.7) for combination therapy (p=0.22), while the mean (SD) Charlson comorbidity scores were 5.0 (3.6) and 4.5 (3.5) for the respective groups (p=0.61). The most common infection source was respiratory tract (54.3%), with Pseudomonas aeruginosa (55.7%) and Acinetobacter baumannii (25.7%) as the most frequently isolated pathogens. The median (IQR) CFDC mean inhibitory concentration (MIC) was 0.5 µg/mL (0.25-1.0). The 30-day mortality rates for the monotherapy and combination groups were 20% and 28.6%, respectively. There was no significant difference in composite clinical success between the groups (p=0.59). Conclusion Our preliminary data suggest that there is no difference in clinical success between CFDC monotherapy and combination therapy with another antibiotic. Further studies are needed to confirm these findings and evaluate the optimal use of CFDC in a variety of clinical settings. Disclosures Michael J. Rybak, PharmD, PhD, MPH, Abbvie, Merck, Paratek, Shionogi, Entasis, La Jolla, T2 Biosystems: Advisor/Consultant

207. The increased frequency and clinical characteristics of Streptococcus agalactiae serotype VIII from blood isolates at two tertiary care hospital in South Korea over 14 years

Abstract Background Invasive group B Streptococcus (GBS) infections are increasing among non-pregnant adults with underlying diseases. Previous studies have shown that the proportion of GBS serotype of pregnant women were differed from geographic regions. However, studies on the serotype of invasive GBS infection in non-pregnant adults are sparse. This study aimed to evaluate epidemiology and clinical characteristics of strains caused GBS bloodstream infection according to serotypes. Methods S. agalactiae blood isolates were collected between March 2007 and December 2021, and their clinical data were obtained from two tertiary hospital of South Korea. Species identification was performed using MALDI-TOF MS and serotyping test was performed using commercial latex particle agglutination kit. Antimicrobial susceptibility tests are conducted using automated equipment. Results A total of 130 patients with GBS bacteremia were identified and among them 125 isolates were serotypeable. The median age were 66 years and 46% were male. Serotype VIII was most dominant (31.5%) and Ib, III, Ia, V were as follows (20.8%, 13.8%, 12.3%, 11.5% retrospectively). The proportion of serotype VIII increased from 27.3% to 53.3% from 2015 to 2021. Most common source of GBS bloodstream infection were primary bacteremia (34.4%), followed by bone and joint infections (16.8%) and skin and soft tissue infections (13.6%). Cardiovascular disease (79.2%) was most frequently reported in GBS bacteremia patients, followed by malignancy (44.6%) and diabetes mellitus (40%). The 30-day mortality rate was 12.3% and there was no difference in 30-day mortality according to serotypes (log rank test P=0.39). In logistic regression analysis, high SOFA score was significantly associated with 30-day mortality (odd ratio 1.28, 95% C.I. 1.28-2.53, P< 0.01). All isolated GBS were susceptible to penicillin and resistances were identified against clindamycin, erythromycin and levofloxacin as 30%, 26.9%, 24.6% of the isolates, respectively. Conclusion We found the most common capsular serotype was VIII (31.5%) in Korea and the proportion of type VIII increasing over time. It is necessary to consider GBS vaccine in adults with underlying disease and its composition for serotype VIII according to epidemiologic characteristics. Disclosures All Authors: No reported disclosures

Network analysis of patterns and relevance of enteric pathogen co-infections among infants in a diarrhea-endemic setting.

Despite significant progress in recent decades toward ameliorating the excess burden of diarrheal disease globally, childhood diarrhea remains a leading cause of morbidity and mortality in low-and-middle-income countries (LMICs). Recent large-scale studies of diarrhea etiology in these populations have revealed widespread co-infection with multiple enteric pathogens, in both acute and asymptomatic stool specimens. We applied methods from network science and ecology to better understand the underlying structure of enteric co-infection among infants in two large longitudinal birth cohorts in Bangladesh. We used a configuration model to establish distributions of expected random co-occurrence, based on individual pathogen prevalence alone, for every pathogen pair among 30 enteropathogens detected by qRT-PCR in both diarrheal and asymptomatic stool specimens. We found two pairs, Enterotoxigenic E. coli (ETEC) with Enteropathogenic E. coli (EPEC), and ETEC with Campylobacter spp., co-infected significantly more than expected at random (both pairs co-occurring almost 4 standard deviations above what one could expect due to chance alone). Furthermore, we found a general pattern that bacteria-bacteria pairs appear together more frequently than expected at random, while virus-bacteria pairs tend to appear less frequently than expected based on model predictions. Finally, infants co-infected with leading bacteria-bacteria pairs had more days of diarrhea in the first year of life compared to infants without co-infection (p-value <0.0001). Our methods and results help us understand the structure of enteric co-infection which can guide further work to identify and eliminate common sources of infection or determine biologic mechanisms that promote co-infection.

In-hospital cardiac arrest due to sepsis – Aetiologies and outcomes in a Swedish cohort study

ObjectivesAwareness of causes of cardiac arrest is essential to prevent them. A recent review found that almost every sixth in-hospital cardiac arrest is caused by infection. Few studies have explored how infections cause cardiac arrest. AimTo describe the features, mechanisms and outcome of sepsis-related cardiac arrests. Material and methodsAll patients ≥18 years who suffered a cardiac arrest at Karolinska University Hospital between 2007 and 2022 with sepsis as the primary cause were included. Data were collected the Swedish Registry for Cardiopulmonary Resuscitation and medical records. The primary outcome was survival to discharge. ResultsOut of 2,327 in-hospital cardiac arrests, 5% (n = 123) suffered it due to sepsis, and 17% (21) survived to hospital discharge. Two thirds of patients were admitted to the hospital due to sepsis and suffered their cardiac arrest after a median of four days. About half (n = 59) had deranged vital signs before the event. Most were witnessed in general wards. In all, 47% (n = 58) had asystole and 24% (n = 30) as the first heart rhythm. The respiratory tract was the most common source of infection. Most patients were undergoing antibiotic therapy and one third had a positive microbiological culture with mixed gram-positive bacteria or Escherichia coli in the urine. ConclusionOur results suggest that sepsis is an uncommon and not increasing cause of in-hospital cardiac arrest and its outcome is in line with other non-shockable cardiac arrests. Deranged respiratory and/or circulatory vital signs precede the event.

Trend and Epidemiology of Tetanus in Nasarawa State, Nigeria: A Five Years Review

Background: Tetanus is a vaccine preventable, non-communicable disease known as lockjaw and characterized by muscle spasm. It is a forgotten disease in the developed world but remained an infection of public health importance in the developing countries. This study aimed to determine the trend in its epidemiology and outcome in Nasarawa state. Subjects and Method: A retrospective study using secondary data from the medical records of three selected health facilities, one each across the three senatorial zones of the state. All those who had tetanus were included while those with incomplete records, 5 were excluded. Data analysis was done using a statistical package for social sciences version 23. The dependent variable was the outcome of tetanus while the independent variables were incubation period, onset period, type of tetanus, risk factors, vaccination history, and manifestations of tetanus. Results: The subject consists of 53.8% males and single with age (Mean=15; SD=6.90). Four and 17 days were the shortest and longest incubation periods while one and six days were the shortest and longest onset periods respectively. A total of 24 (93.3%) patients had generalized tetanus. Nail puncture, road traffic accidents, and umbilical infection were the commonest sources of post-neonatal and neonatal tetanus in this study. Spasm is the commonest manifestation, present in 19 (73.1%) of the study population. This is closely followed by trismus in 57.7% of the cases. About half have a positive vaccination history. This study found case fatality of 7.7%. Conclusion: Generalized tetanus was the commonest type seen in this study, while nail puncture, road traffic accident and umbilical infection were the most common sources of infection. Although, more than half of the study subjects received immunization to prevent tetanus, the case fatality in this study was in one in twelve sufferers. Keywords: Epidemiology, review, tetanus, trend. Correspondence:Bello Surajudeen Oyeleke. Department of Paediatrics Dalhatu Araf Specialist Hospital. Shendam Road, PMB 07, Lafia, Nasarawa State. Email: surajudeenbello4@gmail.com. Mobile: +2347064641540.

Endotoxin removal therapy with Polymyxin B immobilized fiber column: a single center experience from EUPHAS2 registry

Although the precise clinical indication for initiation of PMX-HA is widely debated in the literature, a proper patient selection and timing of treatment delivery might play a critical role in the clinical course of a specific subphenotype of septic shock (endotoxic shock). In light of this view, since 2019, we have introduced in our clinical practice a diagnostic-therapeutic flowchart to select patients that can benefit the most from the treatment proposed. In addition, we reported in this study our experience of PMX-HA in a cohort of critically ill patients admitted to our intensive care unit (ICU). We analyzed a single centre, retrospective, observational web-based database (extracted from the EUPHAS2 registry) of critically ill patients admitted to the ICU between January 2016 and May 2021 who were affected by endotoxic shock. Patients were divided according to the diagnostic-therapeutic flowchart in two groups: Pre-Flowchart (Pre-F) and Post-Flowchart (Post-F). From January 2016 to May 2021, 61 patients were treated with PMX-HA out of 531 patients diagnosed with septic shock and of these, fifty patients (82%) developed AKI during their ICU stay. The most common source of infection was secondary peritonitis (36%), followed by community-acquired pneumonia (29%). Fifty-five (90%) out of 61 patients received a second PMX-HA treatment, with a statistically significant difference between the two groups (78% of the Pre-F vs. 100% of the Post-F group, p = 0.005). In both groups, between T0 and T120, the Endotoxin Activity Assay (EAA) decreased, while the SOFA score, mean arterial pressure (MAP), and Vasoactive Inotropic Score (VIS) improved with no statistically significant difference. Furthermore, when performing a propensity score matching analysis to compare mortality between the two groups, statistically significant lower ICU and 90-day mortalities were observed in the Post-F group [p = 0.016]. Although in this experienced centre data registry, PMX-HA was associated with organ function recovery, hemodynamic improvement, and current EAA level reduction in critically ill patients with endotoxic shock. Following propensity score-matched analysis, ICU mortality and 90-day mortalities were lower in the diagnostic-therapeutic flowchart group when considering two temporal groups based on strict patient selection criteria and timing to achieve PMX. Further Randomised Control Trials focused on centre selection, adequate training and a flowchart of action when assessing extracorporeal blood purification use should be performed.

Re-Operation Rates after Burr-Hole Aspiration of Brain Abscess

Objectives: To determine the re-operation rates after burr-hole aspiration of brain abscess. Materials &amp; Methods: The cross-sectional study was conducted from August 2022 to January 2023 at Jinnah Postgraduate Medical Centre (JPMC). A single burr-hole aspiration was used to treat a total of 64 cerebral abscess patients. Demographics, clinical presentation, predisposing variables, abscess location on imaging, and clinical outcomes were examined in medical records. Results: The study included 64 patients with 60.9% males and 39.1% females. Patients most commonly presented with headache (90.6%) and fever (81.2%) with the majority of patients (92.1%) aged less than 30 years. The commonest source of infection was congenital heart disease (29.6%) in both aspiration and re-aspirations (46.6%). The parietal region was the most common location in both aspiration (32.8%) and re-aspiration (40%) of abscesses with the majority (40%) of re-aspirations done in the 3rd postoperative month. Conclusion: Single burr-hole aspiration is a safe and effective method for the management of brain abscesses. It is a less invasive procedure and is associated with minimal complications. The learning curve is short and safely be performed by neurosurgeons in training. Keywords: Brain abscess, Burr-hole aspiration, Re-aspiration, Infection, Meningitis.

Virulence Mechanisms of Staphylococcal Animal Pathogens.

Staphylococci are major causes of infections in mammals. Mammals are colonized by diverse staphylococcal species, often with moderate to strong host specificity, and colonization is a common source of infection. Staphylococcal infections of animals not only are of major importance for animal well-being but have considerable economic consequences, such as in the case of staphylococcal mastitis, which costs billions of dollars annually. Furthermore, pet animals can be temporary carriers of strains infectious to humans. Moreover, antimicrobial resistance is a great concern in livestock infections, as there is considerable antibiotic overuse, and resistant strains can be transferred to humans. With the number of working antibiotics continuously becoming smaller due to the concomitant spread of resistant strains, alternative approaches, such as anti-virulence, are increasingly being investigated to treat staphylococcal infections. For this, understanding the virulence mechanisms of animal staphylococcal pathogens is crucial. While many virulence factors have similar functions in humans as animals, there are increasingly frequent reports of host-specific virulence factors and mechanisms. Furthermore, we are only beginning to understand virulence mechanisms in animal-specific staphylococcal pathogens. This review gives an overview of animal infections caused by staphylococci and our knowledge about the virulence mechanisms involved.

Native circulating Brucella melitensis lineages causing a brucellosis epidemic in Qinghai, China.

Since 2010, the cases and incidences of human brucellosis have been increasing annually in Qinghai (QH) Province. Molecular epidemiology and phylogenetic analyses of strains from this region are crucial to better understand the transmission of the disease and the evolutionary patterns of Brucella strains. In this study, classical bio-typing assay, multilocus variable-number tandem repeat analysis, and the whole-genome sequencing-single-nucleotide polymorphism approach were used to illustrate the epidemiological and evolutionary patterns of Brucella melitensis. A total of 54 B. melitensis bv. 3 strains were isolated and molecularly characterized, with all strains belonging to the East Mediterranean lineages. Cross-regional transmission events (i.e., between counties) were caused by common sources of infection, suggesting that predominant circulating genotypes are endemic in different regions. Strengthening surveillance in animal brucellosis and controlling infected animals' cross-border movement are necessary. Two strains isolated from humans and marmots were clustered in the same sub-clade, implying the possible existence of direct and/or indirect contact between sheep (and goats) and wildlife (marmots), but this needs to be verified by further investigations. The global-scale phylogenetic analysis indicated that 54 strains sorted into six subclades, four of which formed independent lineages, suggesting that the increase in the incidence rate of human brucellosis may be caused by local circulating lineages. Further strengthening the serology and pathogen surveillance of animals (wildlife) and humans will contribute to an in-depth understanding of the transmission chain of human brucellosis in this region.

Sepsis among Patients Admitted to the Intensive Care Unit of a Tertiary Care Centre.

Sepsis is a life-threatening dysfunction and is one of the common causes of admission in intensive care units. Early diagnosis and management improves the outcome of patients. The aim of this study was to find out the prevalence of sepsis among patients admitted to the intensive care unit of a tertiary care centre. A descriptive cross-sectional study was conducted among patients admitted to the intensive care unit of a tertiary care centre after obtaining ethical approval from the Institutional Review Committee. Data of patients admitted from 1 February 2022 to 31 January 2023 was collected between 6 April 2023 to 27 April 2023. Convenience sampling method was used. The point estimate was calculated at a 95% Confidence Interval. Among 1001 patients, the prevalence of sepsis was 278 (27.77%) (25-30.54, 95% Confidence Interval). Among them, 209 (75.17%) developed septic shock. The mean age was 56.6±19.34 years. Pneumonia 43 (15.46%) and genitourinary infection 43 (15.46%) were the most common sources of infection and the source was unknown in 124 (44.60%) of patients. Hypertension 75 (26.97%) was the most common comorbidity. Acute kidney injury 166 (59.71%) was the most common complication followed by thrombocytopenia 165 (59.35%) and transaminitis 79 (28.41%). The prevalence of sepsis among patients admitted to the intensive care unit was higher than other studies done in similar settings. infection; intensive care unit; sepsis; tertiary care centre.

Docking Complexes of Active Phytochemicals with VK-deficient Genes

Background:: Vitamin K (VK) deficiency occurs when the body does not have enough vitamin K to produce proteins that are essential for blood clotting and bone health. Vitamin K is a cofactor that plays a major role in various comorbidities. Over the years, efforts have been made to identify the interaction between natural compounds, such as K vitamers, that could play a sig-nificant role in regulation of the blood coagulation. We intended to obtain insights into the poten-tial therapeutic implications of phytochemicals for treating VK deficiency-related diseases by in-vestigating the interactions between phytochemicals and VK-deficient genes. Methods:: On active phytochemical docking complexes with VK-deficient genes, there is no spe-cific information available as of yet. In this computationally aided docking study, we were inter-ested in finding the pathogenic blood coagulation-related genes that are linked to VK deficiency. Based on literature reviews and databases, bioactive phytochemicals and other ligands were con-sidered. To provide precise predictions of ligand-protein interactions, docking parameters and scoring algorithms were thoroughly optimized. We have performed molecular docking studies and observed the way the complexes interact. Results:: Specific binding interactions between active phytochemicals and VK pathogenic muta-tions have been identified by the docking study. Hydrogen bonds, van der Waals interactions, and hydrophobic contacts, which are indications of high binding affinities, have been observed in the ligand-protein complexes. Few phytochemicals have demonstrated the ability to interact with the targets of VK-deficient genes, indicating their capacity to modify pathways relevant to VK defi-ciency. The results of the docking study have explained the three pathogenic genes, viz. VWF, F8, and CFTR, wherein VWF and F8 play important roles in blood coagulation and people with cyst-ic fibrosis, to have a deficiency in vitamin K. Thirty-five compounds from different plant and natural sources were screened through molecular docking, out of which two compounds have been considered as controls, including curcumin and warfarin (R-warfarin and S-warfarin), which are the most common anticoagulants readily available in the market. They act by inhibiting vita-min K epoxide reductase (VKOR), which is needed for the gamma-carboxylation of vitamin K-dependent factors. Conclusion:: A focus on other compounds, like theaflavin, ellagic acid, myricetin, and catechin was also made in this study as they show more binding affinity with the three pathogenic proteins. Based on the results, the complexes have been found to possess great potential and thus may be considered for further interaction studies. The potential for active phytochemicals to generate docking complexes with VK-deficient genes is highlighted in this computational analysis. Health disorders related to VK insufficiency may be significantly impacted by these interactions. To val-idate the expected interactions and determine the therapeutic potential of the identified phyto-chemicals, more experimental research, including in vitro and in vivo experiments, is needed.

Mortality and Outcomes of Patients Infected with Extensively Drug-Resistant Bacteria Admitted to Intensive Care Units

Background: The emergence of antimicrobial-resistant pathogens in intensive care units (ICU) makes treatment of these infections very difficult. Objectives: This study aimed to survey the resistance phenotype, risk factors, and possible treatment options for hospital-acquired infections (HAI) at ICUs in a referral university hospital. Methods: Samples were prepared from ICU patients with HAIs. Pathogens were isolated, and the resistance phenotype, prescribed antibiotics, mortality rate, associated risk factors, and clonal relationship of the isolates were assessed. Results: From 100 patients admitted to ICUs, 76 (76%) showed clinical symptoms of HAIs. The most common sources of infection were lung secretions (51.8%). The isolated bacteria were Gram-negative (77, 90.6%) and Gram-positive (9.4%). The most common isolated microorganism was the Acinetobacter baumannii complex (63.5%). The most effective antimicrobials were colistin (96.1%) and linezolid (100%) for Gram-negative and Gram-positive isolates, respectively. An extensively drug-resistant (XDR) phenotype was documented in all isolates of A. baumannii, Pseudomonas aeruginosa, and Serratia marcescens. The XDR phenotype was a significant risk factor only for mortality. A. baumannii had the highest mortality rate (66.6%) among all the isolates. While A. baumannii strains had limited diversity, the other species were highly divergent. Conclusions: The results revealed a high mortality rate for Gram-negative isolates, especially in adenosine triphosphate-binding cassette (ABC). The high genetic similarities of ABC strains might be an indication of neglecting infection control prevention. The use of cotrimoxazole and colistin instead of carbapenems can be promising for mortality reduction in the studied ICUs.

Clinical and Genomic Characterization of a Cohort of Patients With Klebsiella pneumoniae Bloodstream Infection.

The clinical and microbial factors associated with Klebsiella pneumoniae bloodstream infections (BSIs) are not well characterized. Prior studies have focused on highly resistant or hypervirulent isolates, limiting our understanding of K. pneumoniae strains that commonly cause BSI. We performed a record review and whole-genome sequencing to investigate the clinical characteristics, bacterial diversity, determinants of antimicrobial resistance, and risk factors for in-hospital death in a cohort of patients with K. pneumoniae BSI. We identified 562 patients at Massachusetts General Hospital with K. pneumoniae BSIs between 2016 and 2022. We collected data on comorbid conditions, infection source, clinical outcomes, and antibiotic resistance and performed whole-genome sequencing on 108 sequential BSI isolates from 2021 to 2022. Intra-abdominal infection was the most common source of infection accounting for 34% of all BSIs. A respiratory tract source accounted for 6% of BSIs but was associated with a higher in-hospital mortality rate (adjusted odds ratio, 5.4 [95% confidence interval, 2.2-12.8]; P < .001 for comparison with other sources). Resistance to the first antibiotic prescribed was also associated with a higher risk of death (adjusted odds ratio, 5.2 [95% confidence interval, 2.2-12.4]; P < .001). BSI isolates were genetically diverse, and no clusters of epidemiologically and genetically linked cases were observed. Virulence factors associated with invasiveness were observed at a low prevalence, although an unexpected association between O-antigen type and the source of infection was found. These observations demonstrate the versatility of K. pneumoniae as an opportunistic pathogen and highlight the need for new approaches for surveillance and the rapid identification of patients with invasive antimicrobial-resistant K. pneumoniae infection.

Antibacterial activity of Ag-graphene nanocomposites against Gram-Positive and Gram-negative bacteria

Background: Many pathogenic microorganisms, including bacteria, viruses, and fungi, which are common sources of disease and infection in both humans and animals, have a significant impact on human health. To combat these microorganisms, scientists and technicians are steadily attempting to develop novel and potent antimicrobial agents. Recently, graphene nanosheets (GNs) based nanocomposites (NCs) have shown promising potential as antibacterial activity against microorganisms. The present is an attempt to examine the antimicrobial effect of Silver (Ag)/GNs NCs against gram-positive (Bacillus thuringiensis, Staphylococcus aureus, and Enterococcus faecalis) and gram-negative (Salmonella typhi) bacteria. Methods: In this study, Ag/GNs NCs have been synthesized by the solvothermal method. X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), UV-vis spectroscopy, field emission scanning electron microscopy (FESEM), and X-ray photoelectron spectroscopy have all been used to study the Ag/GNs NCs. The antibacterial activity of synthesized GO and Ag/GNs NCs was evaluated against microorganisms using the disk diffusion method. Results: The elemental analysis of synthesized nanomaterial revealed that GO and Ag ions have been reduced by citric acid, and led to the successful formation of Ag/GNs NCs. The resultant NCs have been examined for their antibacterial activity against gram-positive (Bacillus thuringiensis, Staphylococcus aureus, and Enterococcus faecalis) and gram-negative (Salmonella typhi) bacteria. It was observed that Ag/GNs NCs markedly inhibit gram-positive and gram-negative bacteria. Conclusion: The prepared Ag/GNs NCs have the potential for long-term gram-positive and gram-negative bacteria-targeting antibacterial activities and grasp the ability in combating public health threats.

Prevalence and Antimicrobial Resistance Profile of Diarrheagenic Escherichia coli from Fomites in Rural Households in South Africa.

Diarrheagenic Escherichia coli (DEC) pathotypes are the leading cause of mortality and morbidity in South Asia and sub-Saharan Africa. Daily interaction between people contributes to the spreading of Escherichia coli (E. coli), and fomites are a common source of community-acquired bacterial infections. The spread of bacterial infectious diseases from inanimate objects to the surrounding environment and humans is a serious problem for public health, safety, and development. This study aimed to determine the prevalence and antibiotic resistance of diarrheagenic E. coli found in toilets and kitchen cloths in the Vhembe district, South Africa. One hundred and five samples were cultured to isolate E. coli: thirty-five samples were kitchen cloths and seventy-five samples were toilet swabs. Biochemical tests, API20E, and the VITEK®-2 automated system were used to identify E. coli. Pathotypes of E. coli were characterised using Multiplex Polymerase Chain Reaction (mPCR). Nine amplified gene fragments were sequenced using partial sequencing. A total of eight antibiotics were used for the antibiotic susceptibility testing of E. coli isolates using the Kirby-Bauer disc diffusion method. Among the collected samples, 47% were positive for E. coli. DEC prevalence was high (81%), with ETEC (51%) harboring lt and st genes being the most dominant pathotype found on both kitchen cloths and toilet surfaces. Diarrheagenic E. coli pathotypes were more prevalent in the kitchen cloths (79.6%) compared with the toilet surfaces. Notably, hybrid pathotypes were detected in 44.2% of the isolates, showcasing the co-existence of multiple pathotypes within a single E. coli strain. The antibiotic resistance testing of E. coli isolates from kitchen cloths and toilets showed high resistance to ampicillin (100%) and amoxicillin (100%). Only E. coli isolates with hybrid pathotypes were found to be resistant to more than three antibiotics. This study emphasizes the significance of fomites as potential sources of bacterial contamination in rural settings. The results highlight the importance of implementing proactive measures to improve hygiene practices and antibiotic stewardship in these communities. These measures are essential for reducing the impact of DEC infections and antibiotic resistance, ultimately safeguarding public health.

Photodynamic therapy for Cutibacterium acnes decolonization of the shoulder dermis

Introduction Cutibacterium acnes (C. acnes) is a common source of infection in shoulder surgery. 5-Aminolevulinic acid (5-ALA) is a naturally occurring metabolite of C. acnes that creates an exothermic reaction when activated by blue light. The purpose of this study was to evaluate the efficacy of preoperative photodynamic therapy using topical 5-ALA to decrease C. acnes colonization. Methods Patients were randomized to receive topical 5-ALA skin solution activated by blue light photodynamic therapy or standard of care preoperative skin preparation. Prior to skin incision, two punch biopsy specimens were taken from the portal sites and were incubated for 13 days. Culture positivity rate, days until positive, and semiquantitative growth classification were analyzed. Results Fifty patients undergoing arthroscopic shoulder surgery were randomized. The overall positive culture rate was 54%. All cultures were positive for C. acnes except for one. Sixty-four percent of standard preparation patients and 44% of investigational group patients had at least one positive culture for C. acnes. There was no significant difference between groups in patients with at least one positive C. acnes culture ( p = 0.49). Conclusion The use of photodynamic therapy undergoing arthroscopic shoulder surgery did not significantly reduce colonization of C. acnes as compared to standard preparation. Level of Evidence Level II.

Outbreak of highly pathogenic avian influenza A(H5N1) clade 2.3.4.4b virus in cats, Poland, June to July 2023.

BackgroundOver a 3-week period in late June/early July 2023, Poland experienced an outbreak caused by highly pathogenic avian influenza (HPAI) A(H5N1) virus in cats.AimThis study aimed to characterise the identified virus and investigate possible sources of infection.MethodsWe performed next generation sequencing and phylogenetic analysis of detected viruses in cats.ResultsWe sampled 46 cats, and 25 tested positive for avian influenza virus. The identified viruses belong to clade 2.3.4.4b, genotype CH (H5N1 A/Eurasian wigeon/Netherlands/3/2022-like). In Poland, this genotype was responsible for several poultry outbreaks between December 2022 and January 2023 and has been identified only sporadically since February 2023. Viruses from cats were very similar to each other, indicating one common source of infection. In addition, the most closely related virus was detected in a dead white stork in early June. Influenza A(H5N1) viruses from cats possessed two amino acid substitutions in the PB2 protein (526R and 627K) which are two molecular markers of virus adaptation in mammals. The virus detected in the white stork presented one of those mutations (627K), which suggests that the virus that had spilled over to cats was already partially adapted to mammalian species.ConclusionThe scale of HPAI H5N1 virus infection in cats in Poland is worrying. One of the possible sources seems to be poultry meat, but to date no such meat has been identified with certainty. Surveillance should be stepped up on poultry, but also on certain species of farmed mammals kept close to infected poultry farms.

Emergence and potential transmission route of avian influenza A (H5N1) virus in domestic cats in Poland, June 2023.

In June 2023, a fatal disease outbreak in cats occurred in Poland. Most cases tested in Poland (29 of 47) were positive for highly pathogenic avian influenza (HPAI) A (H5N1) virus. Genetic analyses revealed clade 2.3.4.4b with point mutations indicative of initial mammalian hosts adaptations. Cat viral sequences were highly similar (n = 21), suggesting a potential common infection source. To investigate possible infection routes, our group tested food samples from affected households. HPAI H5N1 virus was detected in one poultry meat sample.