Common Infectious Cause Research Articles

A Brg1-Rme1 circuit in Candida albicans hyphal gene regulation.

Major Candida albicans virulence traits include its ability to make hyphae, to produce a biofilm, and to damage host cells. These traits depend upon expression of hypha-associated genes. A gene expression comparison among clinical isolates suggested that transcription factor Rme1, established by previous studies to be a positive regulator of chlamydospore formation, may also be a negative regulator of hypha-associated genes. Engineered RME1 overexpression supported this hypothesis, but no relevant rme1Δ/Δ mutant phenotype was detected. We reasoned that Rme1 may function within a specific regulatory pathway. This idea was supported by our finding that an rme1Δ/Δ mutation relieves the need for biofilm regulator Brg1 in biofilm formation. The impact of the rme1Δ/Δ mutation is most prominent under static or "biofilm-like" growth conditions. RNA sequencing (RNA-seq) of cells grown under biofilm-like conditions indicates that Brg1 activates hypha-associated genes indirectly via repression of RME1: hypha-associated gene expression levels are substantially reduced in a brg1Δ/Δ mutant and partially restored in a brg1Δ/Δ rme1Δ/Δ double mutant. An rme1Δ/Δ mutation does not simply bypass Brg1, because iron homeostasis genes depend upon Brg1 regardless of Rme1. Rme1 thus connects Brg1 to the targets relevant to hypha and biofilm formation under biofilm growth conditions.IMPORTANCECandida albicans is a major fungal pathogen of humans, and its ability to grow as a surface-associated biofilm on implanted devices is a common cause of infection. Here, we describe a new regulator of biofilm formation, RME1, whose activity is most prominent under biofilm-like growth conditions.

The VanS sensor histidine kinase from type-B VRE recognizes vancomycin directly.

When v ancomycin- r esistant e nterococci (VRE) sense the presence of vancomycin, they remodel their cell walls to block antibiotic binding. This resistance phenotype is controlled by the VanS protein, a histidine kinase that senses the antibiotic or its effects and signals for transcription of resistance genes. However, the mechanism by which VanS detects the antibiotic has remained unclear, with no consensus emerging as to whether the protein interacts directly with vancomycin, or instead detects some downstream consequence of vancomycin's action. Here, we show that for one of the most clinically relevant types of VRE, type B, VanS is activated by direct binding of the antibiotic. Such mechanistic insights will likely prove useful in circumventing vancomycin resistance.

Insights into Pathogenesis of Trachoma.

Trachoma is the most common infectious cause of blindness worldwide. This review investigates the pathogenesis of trachoma, focusing on its causative agent, transmission pathways, disease progression, and immune responses. Trachoma is caused by serovars A-C of the bacterium Chlamydia trachomatis (Ct). Transmission occurs through direct or indirect exchanges of ocular and nasal secretions, especially in regions with poor hygiene and overcrowded living conditions. The disease is initiated in early childhood by repeated infection of the ocular surface by Ct. This triggers recurrent chronic inflammatory episodes, leading to the development of conjunctival scarring and potentially to trichiasis, corneal opacity, and visual impairment. Exploring the pathogenesis of trachoma not only unveils the intricate pathways and mechanisms underlying this devastating eye disease but also underscores the multifaceted dimensions that must be considered in its management.

Group B Streptococcus and Intraamniotic Inflammation and Infection.

Intraamniotic inflammation and infection complicate 2% to 5% of term deliveries. Group B Streptococcus (GBS) is a common cause of intraamniotic infection associated with invasive neonatal disease and maternal morbidity. Universal vaginal-rectal screening for GBS colonization is recommended between 36 and 37 weeks. Intrapartum antibiotic prophylaxis is recommended for individuals with positive GBS screens and other risk factors. Intravenous penicillin is the preferred antimicrobial agent. Individuals with penicillin allergies may receive cefazolin for low-risk allergies and either clindamycin or vancomycin for high-risk allergies, depending on their antimicrobial susceptibilities. Clinical trials are underway to evaluate the safety and immunogenicity of maternal anti-GBS vaccine candidates.

Identification of distinct genotypes in circulating RSV A strains based on variants in the virus replication-associated genes.

Respiratory syncytial virus (RSV) is a common cause of respiratory infection that often leads to hospitalization of infected younger children and older adults. RSV is classified into two strains, A and B, each with several subgroups or genotypes. One issue with the definition of these subgroups is the lack of a unified method of identification or genotyping. We propose that genotyping strategies based on the genes coding for replication-associated proteins could provide critical information on the replication capacity of the distinct subgroups, while clearly distinguishing genotypes. Here, we analyzed the virus replication-associated genes N, P, M2, and L from de novo assembled RSV A sequences obtained from 31 newly sequenced samples from hospitalized patients in Philadelphia and 78 additional publicly available sequences from different geographic locations within the United States. In-depth analysis and annotation of variants in the replication-associated proteins identified the polymerase protein L as a robust target for genotyping RSV subgroups. Importantly, our analysis revealed non-synonymous variations in L that were consistently accompanied by conserved changes in its co-factor P or the M2-2 protein, suggesting associations and interactions between specific domains of these proteins. Similar associations were seen among sequences of the related human metapneumovirus. These results highlight L as an alternative to other RSV genotyping targets and demonstrate the value of in-depth analyses and annotations of RSV sequences as it can serve as a foundation for subsequent in vitro and clinical studies on the efficiency of the polymerase and fitness of different virus isolates.IMPORTANCEGiven the historical heterogeneity of respiratory syncytial virus (RSV) and the disease it causes, there is a need to understand the properties of the circulating RSV strains each season. This information would benefit from an informative and consensus method of genotyping the virus. Here, we carried out a variant analysis that shows a pattern of specific variations among the replication-associated genes of RSV A across different seasons. Interestingly, these variation patterns, which were also seen in human metapneumovirus sequences, point to previously defined interactions of domains within these genes, suggesting co-variation in the replication-associated genes. Our results also suggest a genotyping strategy that can prove to be particularly important in understanding the genotype-phenotype correlation in the era of RSV vaccination, where selective pressure on the virus to evolve is anticipated. More importantly, the categorization of pneumoviruses based on these patterns may be of prognostic value.

Function and contribution of two putative Enterococcus faecalis glycosaminoglycan degrading enzymes to bacteremia and catheter-associated urinary tract infection.

Enterococcus faecalis is a common cause of healthcare-acquired bloodstream infections and catheter-associated urinary tract infections (CAUTIs) in both adults and children. Treatment of E. faecalis infection is frequently complicated by multi-drug resistance. Based on protein homology, E. faecalis encodes two putative hyaluronidases, EF3023 (HylA) and EF0818 (HylB). In other Gram-positive pathogens, hyaluronidases have been shown to contribute to tissue damage and immune evasion, but the function in E. faecalis has yet to be explored. Here, we show that both hylA and hylB contribute to E. faecalis pathogenesis. In a CAUTI model, ΔhylA exhibited defects in bladder colonization and dissemination to the bloodstream, and ΔhylB exhibited a defect in kidney colonization. Furthermore, a ΔhylAΔhylB double mutant exhibited a severe colonization defect in a model of bacteremia while the single mutants colonized to a similar level as the wild-type strain, suggesting potential functional redundancy within the bloodstream. We next examined enzymatic activity, and demonstrate that HylB is capable of digesting both hyaluronic acid (HA) and chondroitin sulfate in vitro, while HylA exhibits only a very modest activity against heparin. Importantly, HA degradation by HylB provided a modest increase in cell density during the stationary phase and also contributed to dampening of lipopolysaccharide-mediated NF-κB activation. Overall, these data demonstrate that glycosaminoglycan degradation is important for E. faecalis pathogenesis in the urinary tract and during bloodstream infection.

Thyroid tuberculosis mimicking multinodular goiter: a case report

BackgroundMycobacterium tuberculosis is the second most common infectious cause of death in adults worldwide. The ability of this organism to efficiently establish latent infection has enabled it to spread to nearly one-third of individuals worldwide. Approximately 8 million new cases of active tuberculosis disease occur each year, leading to about 1.7 million deaths. The disease incidence is magnified by the concurrent epidemic of human immunodeficiency virus infection. A total of 1.3 million people died from tuberculosis in 2022. In 2022, an estimated 10.6 million people fell ill with tuberculosis worldwide, including 5.8 million men, 3.5 million women, and 1.3 million children. We report a case of thyroid tuberculosis presenting as multinodular goiter. Neck ultrasound was done and revealed abscess collection on the background of multinodular colloid goiter. The diagnosis of thyroid tuberculosis was confirmed by a positive GeneXpert of the pus sample and the presence of extensive caseous necrosis on cytopathology examination. Furthermore, anterior neck swelling may provide a diagnostic challenge by clinically mimicking multinodular goiter or thyroid neoplasms. Owing to its rarity and its tendency to pose a clinical diagnostic challenge, we decided to report it.Case presentationA 60-year-old retired female Ethiopian high-school teacher presented to University of Gondar Hospital, Gondar, Ethiopia with firm, nontender multinodular anterior neck swelling measuring at largest 2 × 3 cm that moves with swallowing. GeneXpert of the pus sample and cytopathology examination confirmed the diagnosis of thyroid tuberculosis, and the patient was started on 2 rifampicin−ethambutol−isoniazid−pyrazinamide/4 rifampicin−isoniazid 3 tablets by mouth/day, which is defined as the preferred first-line anti-tuberculosis regimen in Ethiopia, and pyridoxine 50 mg by mouth per day for 6 months. Since then, she has been followed with regular liver function tests. The patient has shown a smooth course with no significant adverse effects encountered. Currently, the patient has completed her anti-tuberculosis treatment and is doing well.ConclusionIn the clinical evaluation of a patient with anterior neck swelling, tuberculosis must be considered as a differential diagnosis in subjects from endemic areas for early diagnostic workup and management.

A Rare Case of Invasive Thyroid Aspergillosis Revealed on 18F-FDG-PET/CT.

Invasive aspergillosis (IA) represents a common form of fungal infection caused by various species of Aspergillus that most frequently affect immunocompromised patients. Typically, this disease occurs preferentially in high-risk groups including patients infected with the human immunodeficiency virus (HIV), patients with leukemia, patients with autoimmune diseases, and organ transplant patients undergoing medical immunosuppression. Considered the second most common cause of opportunistic fungal infection in humans after Candida albicans, this pathogen predominantly affects the lungs, but it may also spread by a hematogenous route to various organs and have a heterogeneous presentation. Owing to its high iodine levels, high perfusion, and enclosed capsule, the thyroid gland is considered to have a lower susceptibility to microbial invasion, and it is fairly uncommon to find associated infectious nodules. In metabolic imaging, 18F-FDG-PET/CT has become increasingly useful for detecting a wide range of infectious and inflammatory diseases and is already the gold standard for certain indications. According to the literature, no studies of hypermetabolic nodular thyroid aspergillosis on 18F-FDG-PET/CT confirmed on histology have yet been reported. Here, we report the first case of a patient with a heterogeneous presentation of IA and the presence of a hypermetabolic nodule in the thyroid with a surprising result.

Impact of the COVID-19 pandemic on extended-spectrum β-lactamase producing Escherichia coli in urinary tract and blood stream infections: results from a nationwide surveillance network, Finland, 2018 to 2022

BackgroundBefore the COVID-19 pandemic there has been a constant increase in antimicrobial resistance (AMR) of Escherichia coli, the most common cause of urinary tract infections and bloodstream infections. The aim of this study was to investigate the impact of the COVID-19 pandemic on extended-spectrum β-lactamase (ESBL) production in urine and blood E. coli isolates in Finland to improve our understanding on the source attribution of this major multidrug-resistant pathogen.MethodsSusceptibility test results of 564,233 urine (88.3% from females) and 23,860 blood E. coli isolates (58.8% from females) were obtained from the nationwide surveillance database of Finnish clinical microbiology laboratories. Susceptibility testing was performed according to EUCAST guidelines. We compared ESBL-producing E. coli proportions and incidence before (2018–2019), during (2020–2021), and after (2022) the pandemic and stratified these by age groups and sex.ResultsThe annual number of urine E. coli isolates tested for antimicrobial susceptibility decreased 23.3% during 2018–2022 whereas the number of blood E. coli isolates increased 1.1%. The annual proportion of ESBL-producing E. coli in urine E. coli isolates decreased 28.7% among males, from 6.9% (average during 2018–2019) to 4.9% in 2022, and 28.7% among females, from 3.0 to 2.1%. In blood E. coli isolates, the proportion decreased 32.9% among males, from 9.3 to 6.2%, and 26.6% among females, from 6.2 to 4.6%. A significant decreasing trend was also observed in most age groups, but risk remained highest among persons aged ≥ 60 years.ConclusionsThe reduction in the proportions of ESBL-producing E. coli was comprehensive, covering both specimen types, both sexes, and all age groups, showing that the continuously increasing trends could be reversed. Decrease in international travel and antimicrobial use were likely behind this reduction, suggesting that informing travellers about the risk of multidrug-resistant bacteria, hygiene measures, and appropriate antimicrobial use is crucial in prevention. Evaluation of infection control measures in healthcare settings could be beneficial, especially in long-term care.

Povidone-iodine in vitro antiseptic efficacy as a function of exposure duration, concentration, preparation, and length of storage.

Although 5% povidone-iodine (PVP-I) is frequently used as an ocular antiseptic agent, there is a lack of consensus regarding the effects of PVP-I concentration, storage after opening, and compounded preparation on PVP-I antisepsis. We performed a series of in-vitro experiments to determine the impact of these factors on PVP-I's inhibition of common causes of post-procedural eye infection. Inhibition of microorganism growth was measured in-vitro as a function of active PVP-I exposure time. In control experiments, PVP-I was inactivated before microorganism exposure. Tested PVP-I solutions varied in concentration (0.6%, 5%, or 10%), length of storage after opening (0, 7, or 30days), and preparation (commercial vs.compounded from stock PI solution). Tested pathogens included S. epidermidis, S. viridans, P. aeruginosa, methicillin-resistant S. aureus, methicillin-sensitive S. aureus, and C. albicans. PVP-I solutions inhibited all bacterial growth by 3min and fungal growth by 15s. Compared to 5% PVP-I, the 0.6% PVP-I was less effective in inhibiting S. viridans growth (200 ± 0 colonies vs. 7 ± 8 at 30s, P = 0.0004; 183 ± 21 vs. 0 ± 0 at 1min, P = 0.018), but more effective in inhibiting P. aeruginosa (30 ± 20 vs. 200 ± 0 at 15s, P = 0.019). Compared to commercial and newly-opened PVP-I solutions, compounded preparations and solutions stored for 7 or 30days after bottle opening either preserved or improved antiseptic efficacy against tested microorganisms. Concentration of PVP-I solution affects antiseptic efficacy within 1min of exposure, but all solutions performed equivalently at 3min. In contrast to results of prior studies investigating dilute PVP-I, the 0.6% PVP-I did not demonstrate a uniformly equivalent or superior anti-septic effect. Compounded preparation and storage length after bottle opening did not decrease PVP-I antiseptic activity.

Neonatal Enteroviral Meningoencephalitis: Clinical and Paraclinical Characteristics of a Nosocomial Outbreak in Colombia

Enteroviruses (EVs) are a common cause of infection in neonates, they spread from person to person by a variety of routes and can cause severe symptoms and complications, including meningoencephalitis, myocarditis, and hepatic failure. We report the clinical and paraclinical characteristics of six patients diagnosed in a hospital cluster with late-onset sepsis, mostly preterm newborns. The most common symptoms were the same as a sepsis-like syndrome, the predominant sign of presentation was fever. The most frequent laboratory finding was elevated C-reactive protein, and later positive cerebrospinal fluid multiplex for EVs. Support treatment was given. A benign course was observed. Seizures were the only complication, with a normal electroencephalography at 6-month follow-up. In-hospital cases would benefit from a high clinician suspicion and early detection for achieving immediate isolation and containment measures to limit the spread to sick and vulnerable newborns, avoiding clusters.

Granulomatosis with polyangiitis masquerading as disseminated tuberculosis in presence of bilateral lung cavities and hemorrhagic infarct

Lung cavitations with constitutional symptoms are usually associated with pulmonary tuberculosis due to its high prevalence and are the most common infectious cause in India. Granulomatosis with polyangiitis (GPA) with the systemic pulmonary disease will have different radiological presentations such as nodule, mass, and consolidation with or without cavitation. In this case report, we have reported a 40-year-old female presented with cough, fever, and weight loss of 6 months duration with chest imaging suggestive of bilateral cavitary lung disease. She was labeled as a case of disseminated tuberculosis due to involvement of the central nervous system and empirically treated with anti-tuberculosis treatment (ATT) without microbiological evidence of tuberculosis in smear and cartridge-based nucleic acid amplification tests. The absence of clinical response and radiological worsening to empirical ATT gives a clue for an alternate diagnosis. Bronchoscopy workup documented Aspergillus colonization and vasculitis workup in the presence of cavitary lung disease documented abnormally raised proteinase 3 anti-neutrophil cytoplasmic antibodies titers. She was treated with a combination of systemic methylprednisolone and azathioprine with voriconazole. Her clinical response was observed in 4 weeks and radiological response with complete radiological clearance of pulmonary cavitations was documented after 6 months of treatment. We recommend prompt workup and ruling out GPA in all cases with pulmonary cavitations with negative microbiological workup and no empirical ATT should be given in the era of rapid microbiological tests with good sensitivity and specificity.

The Next Target for Readmission Reporting? Exploring Readmission Rates of Patients with CLABSI

Background: Multi-drug resistant organisms (MDROs) are a common cause of healthcare-associated infections, particularly central line-associated bloodstream infections (CLABSIs). Prior research has shown that MDROs cause up to 67% of CLABSIs and have up to a 37% increase in 30 day readmission, which is higher than readmission rates for other conditions reported to the Centers for Medicare and Medicaid Services (CMS). The objective of the study was to determine overall 90-day readmission rates, and if there was a difference in readmission rate within 90 days post discharge for patients who had a MDRO as the causative pathogen of their CLABSI compared to patients who did not have an MDRO. Methods: A retrospective analysis of patient data from a nine-hospital system was performed on patients who had a CLABSI and were discharged alive between January 1st, 2018, and December 31st, 2019. Basic descriptive statistics were performed, and the potential differences in readmission rates were examined using Chi-square analyses. Results: The overall readmission rate for all CLABSIs was 46.9%. The chi-square analysis determined there was not a significant difference in readmission rates in patients who had a MDRO CLABSI compared to patients with a non-MDRO CLABSI (59.1% vs. 44.6%, x2= 1.564 , p= 0.211). Conclusion: There was not a significant difference in readmission rates between patients with an MDRO CLABSI compared to a non-MDRO CLABSI. However, the overall readmission rate for this patient population was much higher than seen in previous literature and other publicly reported readmission rates. Additional research is recommended to explore if the increased CLABSI readmission rates seen are a unique finding to this health system.

Assessing chlorhexidine resistance in MRSA isolates from hospitals in Cleveland, OH and Detroit, MI

Background: Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most common causes of procedure-related, skin, and soft-tissue infections. Hospitalized patients who are colonized with MRSA are at a higher risk of developing invasive infections after discharge. Chlorhexidine, an antiseptic/disinfectant, has been used to reduce carriage and prevent infections in these patients. Studies have shown chlorhexidine resistance among MRSA strains. Chlorhexidine resistance is associated with qac genes, which encode multidrug efflux pumps that increase bacterial tolerance to disinfectant agents. The global distribution and prevalence of qacA and qacB genes are highly variable. One study reported that qacA and qacB genes could be found in 0.9% - 83.3% of clinical MRSA isolates worldwide. The goal of this study was to determine the prevalence of chlorhexidine resistance and identify the resistance-associated genes from our MRSA samples using whole genome sequencing (WGS). Methods: 474 MRSA samples were obtained from hospitals in Detroit, MI (287) and Cleveland, OH (187). Whole genome sequencing was performed using the NextSeq (Illumina Inc., CA) platform. The sequencing data was analyzed using ResFinder 4.1, a publicly available database that can be used to identify acquired genes and chromosomal mutations mediating antimicrobial resistance. The output was organized into a data sheet to visualize the presence of the genes of interest. Results: The qacA gene was present in only one MRSA sample from the Cleveland area hospital. In the samples from Detroit, 14 out of 287 showed disinfectant resistance genes. The qacA, qacB, and qacD were present in 1, 6, and 7 samples, respectively. The prevalence of any qac gene in the Cleveland area samples was 0.5%. Meanwhile, the prevalence of any qac gene in Detroit area samples was 4.9%. Among the 7 samples that have qacD gene, 6 samples have more than one copy of qacD. Conclusions: The prevalence of the “qac” gene varied widely based on the origin of the samples. Detroit area samples had more qac genes prevalence than Cleveland area samples. Chlorhexidine is a widely used antiseptic/disinfectant, and it plays a vital role in reducing carriage and preventing infection among hospitalized patients colonized with MRSA. Monitoring and addressing MRSA-reduced susceptibility to chlorhexidine is imperative for maintaining the effectiveness of infection control practices such as decolonization.

The Association Between Antibiotic Resistance and Biofilm Production in Klebsiella pneumoniae Isolated from Urinary Tract Infections.

Background and aims This research investigates the link between biofilm formation and antibiotic resistance among Klebsiella pneumoniae bacteria in Sana'a city, Yemen, a common cause of hospital-acquired infections and community-acquired infections. Methods: A 6-month study investigated 300 urinary tract infections samples, with 241 culture-positive. Standard methods were used for isolation and identification, including biofilm production and antibiogram susceptibility patterns of Klebsiella pneumoniae. Results: The study reveals that penicillin resistance is linked to Klebsiella pneumoniae's ability to form biofilms. Ampicillin-resistant isolates formed biofilms 97.5% of the time, while non-biofilm-producing isolates had a lower rate of resistance. Carbapenem group resistance was also significant, with Meropenem-resistant isolates forming biofilms 42.5% of the time. Cephalosporin resistance ranged from 80-95% for Biofilm-Forming Isolates, while Quinolones resistance ranged from 65-82%. Aminoglycoside resistance was also significant, with gentamicin and amikacin resistance rates being 42.5% and 42.5%, respectively. These findings highlight the importance of understanding the phenotypes of Klebsiella pneumoniae in forming biofilms. Conclusion: The study found a strong correlation between the biofilm production of Klebsiella pneumoniae and antibiotic resistance, with quinolones and cephalosporins being the least active, while carbapenems and aminoglycosides showed slight sensitivity.

Gastrointestinal parasitic infections: Prevalence and risk factors in West Ismailia, Arab Republic of Egypt

BackgroundThis study aimed to determine the prevalence of gastrointestinal parasites (GIP) in the rural community of West Ismailia and its associated risk factors. Human infection by GIP is natural and expected. There are few records concerning parasitic infection in the rural areas of the Ismailia Governorate.MethodsFrom 520 individuals, sociodemographic and risk factors information were retrieved. Fecal samples were collected, concentrated, and tested for GIP infection using a microscopic examination.ResultsThe West Ismailia study population had a 40.4% prevalence of GIP infection, including single and concomitant parasite infections. The most common cause of GIP infection was protists (38%). Entamoeba sp., Blastocystis sp., and G. duodenalis were the most common parasites. Poly-parasitism was prevalent within the West Ismailia region. Age, abdominal symptoms, perianal itching, ownership of numerous animal species, exposure to turbid water, previous parasitic infection (PPI), and non-treatment reception of PPI were all considered significant factors associated with GIP infection. Specific individuals from the same family have been observed to have identical GIP.ConclusionGIP infection remains underestimated in rural areas. Periodic screening and treatment for GIP infection in children and public education on GIP hazards and prevention, focusing on personal hygiene, are recommended. Family members of affected individuals should be screened and treated for GIP.

Surveillance and Prediction of Risk Factors for Central Line-Associated Bloodstream Infections in Saudi Arabia.

Although central line-associated bloodstream infection (CLABSI) is the most common type of healthcare-associated infection among patients with inserted devices, few studies have comprehensively evaluated the related risk factors. This retrospective study analyzed the risk factors, predictors, causative organisms, and impact of CLABSI on clinical outcomes mortality, and length of stay (LOS) in older adults. We included 36 patients diagnosed with CLABSI according to the Centers for Disease Control and Prevention criteria at King Abdulaziz University Hospital during 2013-2014 casesand 375 control patients controls. Risk factors were evaluated using a multivariate logistic regression analysis. Cases and controls did not differ significantly in age or sex distribution. However, cases had a significantly longer LOS than controls 78 vs. 19 days, p < 0.001. One-third of 12/36 CLABSI cases were admitted to the medical intensive care unit (MICU). Most had renal disease, acute coronary syndrome, and used steroids. Additionally, 34 cases (94.4%) and 2 cases (5.6%) presented with primary and secondary infections, respectively, and hypotension was the most prevalent symptom (12/36).The internal jugular vein was the most common insertion site, and the nasogastric tube and mechanical ventilator were the most common insertion devices. Seven cases died, and three deaths were attributed to bloodstream infection (BSI). The most common cause of blood infection was Staphylococcus epidermidis, followed by Klebsiella pneumoniae. The present study reveals age, LOS, total parenteral nutrition/partial parenteral nutrition (TPN/PPN), and transplantation as the independent risk factors/predictors of CLABSI.

Completed genome and emergence scenario of the multidrug-resistant nosocomial pathogen Staphylococcus epidermidis ST215

BackgroundA multidrug-resistant lineage of Staphylococcus epidermidis named ST215 is a common cause of prosthetic joint infections and other deep surgical site infections in Northern Europe, but is not present elsewhere. The increasing resistance among S. epidermidis strains is a global concern. We used whole-genome sequencing to characterize ST215 from healthcare settings.ResultsWe completed the genome of a ST215 isolate from a Swedish hospital using short and long reads, resulting in a circular 2,676,787 bp chromosome and a 2,326 bp plasmid. The new ST215 genome was placed in phylogenetic context using 1,361 finished public S. epidermidis reference genomes. We generated 10 additional short-read ST215 genomes and 11 short-read genomes of ST2, which is another common multidrug-resistant lineage at the same hospital. We studied recombination’s role in the evolution of ST2 and ST215, and found multiple recombination events averaging 30–50 kb. By comparing the results of antimicrobial susceptibility testing for 31 antimicrobial drugs with the genome content encoding antimicrobial resistance in the ST215 and ST2 isolates, we found highly similar resistance traits between the isolates, with 22 resistance genes being shared between all the ST215 and ST2 genomes. The ST215 genome contained 29 genes that were historically identified as virulence genes of S. epidermidis ST2. We established that in the nucleotide sequence stretches identified as recombination events, virulence genes were overrepresented in ST215, while antibiotic resistance genes were overrepresented in ST2.ConclusionsThis study features the extensive antibiotic resistance and virulence gene content in ST215 genomes. ST215 and ST2 lineages have similarly evolved, acquiring resistance and virulence through genomic recombination. The results highlight the threat of new multidrug-resistant S. epidermidis lineages emerging in healthcare settings.

CONCURRENT KLEBSIELLA BACTEREMIA IN TWO INFANTS WITH SEVERE RESPIRATORY SYNCYTIAL VIRUS INFECTION.

Respiratory syncytial virus (RSV) is the most common cause of lower respiratory tract infections in children. In most previously healthy infants, RSV infection is self-limited and resolves without complications. The risk of bacteremia is low in young febrile infants with RSV infection. Herein, we report two previously healthy infants with severe RSV infection who had concurrent Klebsiella bacteremia.

Longitudinal humoral analysis in RSV-infected infants identifies pre-existing RSV strain-specific G and evolving cross-reactive F antibodies

Respiratory syncytial virus (RSV) is among the most common causes of lower respiratory tract infection (LRTI) and hospitalization in infants. However, the mechanisms of immune control in infants remain incompletely understood. Antibody profiling against attachment (G)and fusion (F)proteins in children less than 2 years of age, with mild (outpatients) or severe (inpatients) RSV disease, indicated substantial age-dependent differences in RSV-specific immunity. Maternal antibodies were detectable for the first 3months of life, followed by a long window of immune vulnerability between 3 and 6months and a rapid evolution of FcγR-recruiting immunity after 6months of age. Acutely ill hospitalized children exhibited lower G-specific antibodies compared with healthy controls. With disease resolution, RSV-infected infants generated broad functional RSV strain-specific G-responses and evolved cross-reactive F-responses, with minimal maternal imprinting. These data suggest an age-independent RSV G-specific functional humoral correlate of protection, and the evolution of RSV F-specific functional immunity with disease resolution.