Causative Pathogen In Patients Research Articles

Screening and Isolation of Protease Producing Bacteria from Diabetic Foot Ulcers

This study was conducted to detect bacterial causative pathogens in patients with diabetes foot ulcer infections and determine the protease enzyme. Samples were collected from 75 swabs were collected from patients suffering from diabetic foot ulcers referred to The Diabetic Center /Thi-Qar province. Data collected from patients included: age, gender and Period of infection. The results revealed that positive bacterial growth appeared in 54 (72 %) of diabetic foot ulcer specimen, and the most common isolates were Enterobacter cloaca 15(27.77%), followed by proteus mirabilis 12 (22.22%), Staphylococcus aureus 10 (18.51%), Escherichia coli 8 (14.81%), for each one Klebsiella pneumonia, Pseudomonas aeruginosa and Streptococcus pyogens 3(0.84%). The results of the Protease enzyme test were performed for all 54 isolates to determine the variable ability of these bacterial species isolated from didactic foot ulcers to produce this enzyme. The highest percentage production protease enzyme was 100 % for Pseudomonas aeruginosa, Staphylococcus aureus and 76.92% for proteus mirabilis, while the isolates showed a low production of 20.0 % for Enterobacter cloaca.

A novel score for early prediction of urinary tract infection risk in patients with acute ischemic stroke: a nomogram-based retrospective cohort study

This study aimed to construct and externally validate a user-friendly nomogram-based scoring model for predicting the risk of urinary tract infections (UTIs) in patients with acute ischemic stroke (AIS). A retrospective real-world cohort study was conducted on 1748 consecutive hospitalized patients with AIS. Out of these patients, a total of 1132 participants were ultimately included in the final analysis, with 817 used for model construction and 315 utilized for external validation. Multivariate regression analysis was applied to develop the model. The discriminative capacity, calibration ability, and clinical effectiveness of the model were evaluated. The overall incidence of UTIs was 8.13% (92/1132), with Escherichia coli being the most prevalent causative pathogen in patients with AIS. After multivariable analysis, advanced age, female gender, National Institute of Health Stroke Scale (NIHSS) score ≥ 5, and use of urinary catheters were identified as independent risk factors for UTIs. A nomogram-based SUNA model was constructed using these four factors (Area under the receiver operating characteristic curve (AUC) = 0.810), which showed good discrimination (AUC = 0.788), calibration, and clinical utility in the external validation cohort. Based on four simple and readily available factors, we derived and externally validated a novel and user-friendly nomogram-based scoring model (SUNA score) to predict the risk of UTIs in patients with AIS. The model has a good predictive value and provides valuable information for timely intervention in patients with AIS to reduce the occurrence of UTIs.

Lemierre syndrome: a hidden complication of sore throats

BackgroundLemierre syndrome is a rare but potentially life-threatening condition characterized by septic thrombophlebitis of the internal jugular vein, most commonly caused by Fusobacterium necrophorum.Case presentationA 46-year-old woman with no significant medical history presented with generalized neck swelling and fever. Despite seeking medical attention at multiple outpatient clinics for upper respiratory symptoms lasting 10 days, she only received symptomatic treatment for acute viral pharyngitis. A computed tomography (CT) scan of her neck revealed thrombophlebitis in the left internal jugular vein, and subsequent cultures indicated the presence of Klebsiella pneumoniae. The patient’s oxygen saturation levels suddenly dropped, and the CT scan identified bilateral peripheral consolidation areas in both lungs, consistent with septic emboli. These findings were consistent with a diagnosis of Lemierre syndrome. The patient was treated with 2 weeks of intravenous piperacillin/tazobactam and vancomycin, as well as anticoagulation therapy using heparin, and her symptoms resolved completely.ConclusionThis report presents an unusual occurrence of Lemierre syndrome caused by K. pneumoniae, a less frequently encountered causative pathogen in patients without diabetes mellitus. The case highlights the significance of timely and appropriate antibiotic use to prevent potential complications.

The diagnostic and clinical utility of microbial cell-free DNA sequencing in a real-world setting

Microbial cell free DNA sequencing is increasingly used for diagnosis of infection but few studies describe its utility in real-world settings. We performed a single-center retrospective case series of microbial cell free DNA testing using the Karius assay from 29 patient samples to define the clinical reasoning and the impact of testing. Indications fell into 3 categories, identifying a causative pathogen in patients with an infectious syndrome and negative microbiologic workup (15/29, 52%), seeking another pathogen when organisms identified by traditional diagnostics failed to explain the clinical presentation (9/29, 31%) and to "rule out" infection in patients with nonspecific symptoms and negative microbiologic workup (5/29, 17%). Clinical impact was positive in 13/29 (45%) and all were for patients with high pretest probability for infection. Impact was negative in 3/29 (10%) cases. There was no impact in 15/29 (52%) cases. Further work is needed to define the optimal timing accounting for test performance, and patient characteristics.

Usefulness of the FilmArray blood culture identification panel for identifying causative pathogens of bone and joint infections

As bone and joint infections (BJIs) require long-term treatment, identifying their causative pathogens is vital. However, the detection rate of conventional culturing remains inadequate. This study aimed to evaluate the usefulness of the FilmArray blood culture identification (BCID) panel for identifying causative pathogens in patients with BJIs. We tested a BCID panel using collected samples, in addition to conventional cultures. The primary outcome was to evaluate the diagnostic performance of the BCID panel, calculated using conventional culturing methods. A total of 44 patients who underwent BJI-related specimen collection were enrolled. Of the 44 patients, 22 were diagnosed with a BJI. Conventional culture identified 15 of 22 organisms (68.2%), whereas the BCID panel identified 14 of 22 organisms (63.4%). The overall sensitivity and specificity of the BCID panel were 73.3% and 57.1%, respectively, compared to those of the conventional culture. However, the sensitivity reached 100% when only pathogens included in the BCID panel were considered. In seven culture-negative cases, the BCID panel identified three organisms (42.9%). The BCID panel also indicated the appropriate therapy against a BJI caused by methicillin-resistant Staphylococcus aureus by detecting the mecA gene. This study demonstrated that the BCID panel has the potential for early and accurate diagnosis of the causative organism of BJI using specimens such as joint fluid and bone tissue. Our results suggest that BCID panels, in addition to routine culture, may improve our ability to diagnose the causative microorganisms of BJI in clinical practice, thereby contributing to the selection of appropriate antimicrobial agents.

Next-Generation Sequencing for Infectious Disease Diagnosis

Current diagnostic methods do not sufficiently identify disease-causing pathogens in severe infectious diseasecases. Prompt identification of causative microorganisms would improve the disease outcome because of antimicrobial treatment optimization. Next-generation sequencing (NGS) is a culture-free method that analyzes theentire microbial community within a sample. Metagenomic sequencing allows us to comprehensively and quantitatively obtain the genes in all organisms present in a clinical sample. Previous studies have attempted to identifypathogens using NGS in various infectious diseases; however, there are currently no established standard protocols to identify causative microorganisms. To establish the standard NGS methods for infectious diseases, studieshave been conducted for severe infectious diseases in our laboratory: acute encephalitis and encephalopathy,acute liver failure, acute myocarditis, blood stream infection and febrile neutropenia under immunocompromisedconditions, and respiratory failure. NGS has advantages over current diagnostic methods in identifying causativepathogens in patients with severe infectious diseases. The routine diagnostic workflow using NGS is expected tobe introduced in clinical settings. NGS can potentially be used to comprehensively analyze drug resistance mutations. Because a number of drug resistance mutations have been reported in patients with cytomegalovirus (CMV)infections treated with ganciclovir, full-length antiviral gene mutation analysis was conducted in congenital CMVinfections. Moreover, NGS can reveal the background microbiome in clinical samples of infectious diseases. Recently, we investigated neonatal respiratory distress-associated microorganisms from microbial genes found inplasma and gastric fluid and assessed their relationship with clinical findings. Because NGS is a comprehensiveanalysis, potential solutions, excluding identifying causative pathogens, are expected to be found.

Next-Generation Sequencing to Detect Pathogens in Pediatric Febrile Neutropenia: A Single-Center Retrospective Study of 112 Cases.

Background Febrile neutropenia (FN) is a frequent complication in immunocompromised patients. However, causative microorganisms are detected in only 10% of patients. This study aimed to detect the microorganisms that cause FN using next-generation sequencing (NGS) to identify the genome derived from pathogenic microorganisms in the bloodstream. Here, we implemented a metagenomic approach to comprehensively analyze microorganisms present in clinical samples from patients with FN.MethodsFN is defined as a neutrophil count <500 cells/µL and fever ≥37.5°C. Plasma/serum samples of 112 pediatric patients with FN and 10 patients with neutropenia without fever (NE) were sequenced by NGS and analyzed by a metagenomic pipeline, PATHDET.ResultsThe putative pathogens were detected by NGS in 5 of 10 FN patients with positive blood culture results, 15 of 87 FN patients (17%) with negative blood culture results, and 3 of 8 NE patients. Several bacteria that were common in the oral, skin, and gut flora were commonly detected in blood samples, suggesting translocation of the human microbiota to the bloodstream in the setting of neutropenia. The cluster analysis of the microbiota in blood samples using NGS demonstrated that the representative bacteria of each cluster were mostly consistent with the pathogens in each patient.ConclusionsNGS technique has great potential for detecting causative pathogens in patients with FN. Cluster analysis, which extracts characteristic microorganisms from a complex microbial population, may be effective to detect pathogens in minute quantities of microbiota, such as those from the bloodstream.

Vitreous and Chorioretinal Lesions in People Who Inject Drugs and Are Hospitalized with Bloodstream and Related Infections

To determine the prevalence of and to characterize vitreous and chorioretinal lesions, to identify causative organisms, and to correlate symptoms with ophthalmic involvement in people who inject drugs and are hospitalized with bloodstream infection (BSI), related metastatic foci of infection (MFI), or both. An academic hospital-based cross-sectional study. Patients admitted with BSI or MFI related to injection drug use (IDU). Patients underwent a complete eye examination within 72 hours of enrollment. Characteristics including gender; age; race; injection drug of choice (DOC); presence of coinfection with hepatitis B, hepatitis C, or human immunodeficiency virus; pathogen causing systemic infection and type of infection; and history of prior infection related to IDU were recorded. Presence of vitreous or chorioretinal findings, or both. Ninety-one unique patients with 96 separate hospitalizations for systemic infection were enrolled from March 28, 2018, through March 30, 2020. Vitreous or chorioretinal involvement was identified in 16 of 96 patients (16.7%). The most common ocular findings were intraretinal or white-centered hemorrhage in 9 of 96 patients, chorioretinal infiltrate in 8 of 96 patients, endophthalmitis in 5 of 96 patients, and cotton wool spots in 3 of 96 patients. Of the patients with ocular involvement, only 7 of 16 patients (44%) were symptomatic, and 5 of these were patients with endophthalmitis; the others showed chorioretinal infiltrates or intraretinal or white-centered hemorrhage and cotton wool spots. Staphylococcus aureus was the most common causative pathogen in patients with and without ocular findings. Presence of ocular symptoms, worse visual acuity, and injection DOC of methamphetamine were correlated with the presence of ocular findings. Patients without ocular symptoms with systemic infections related to IDU may have chorioretinal findings. Further study is needed to characterize better the epidemiologic features of these infections and to identify risk factors for ocular involvement in people who inject drugs.

Impaired host response and the presence of Acinetobacter baumannii in the serum microbiome of type-II diabetic patients.

SummaryType II diabetes (T2D) affects over 10% of the US population and is a growing disease worldwide that manifests with numerous comorbidities and defects in inflammation. This dysbiotic host response allows for infection of the host by numerous microorganisms. In the course of T2D disease, individuals can develop chronic infections including foot ulcers and periodontitis, which lead to further complications and opportunistic infections in multiple body sites. In this study, we investigated the serum of healthy subjects and patients with T2D with (T2DP) or without periodontitis for both microbiome signatures in addition to cytokine profiles. Surprisingly, we detected the presence of Acinetobacter baumanii in the serum of 23% individuals with T2D/T2DP tested. In T2DP, IL-1β, TNF-α, MCP-1, IL-6, IL-8, and IFN-γ were significantly elevated in ABC-positive subjects. As an emerging pathogen, A. baumanii infection represents a risk for impaired inflammation and the development of comorbidities in subjects with T2D.

Precision diagnosis and therapy of a case of brain abscesses associated with asymptomatic pulmonary arteriovenous fistulas

BackgroundBrain abscesses, a severe infectious disease of the CNS, are usually caused by a variety of different pathogens, which include Streptococcus intermedius (S. intermedius). Pulmonary arteriovenous fistulas (PAVFs), characterized by abnormal direct communication between pulmonary artery and vein, are a rare underlying cause of brain abscesses.Case presentationThe patient was a previous healthy 55-year-old man who presented with 5 days of headache and fever. Cerebral magnetic resonance imaging (MRI) suggested a brain abscess. Thoracic CT scan and angiography demonstrated PAVFs. Aiding by metagenomic next-generation sequencing (mNGS) of the cerebrospinal fluid (CSF) sample which identified S. intermedius as the causative pathogen, the patient was switched to the single therapy of large dose of penicillin G and was cured precisely and economically.ConclusionsIt is an alternative way to perform mNGS to identify causative pathogens in patients with brain abscesses especially when the results of traditional bacterial culture were negative. Further thoracic CT or pulmonary angiography should also be undertaken to rule out PAVFs as the potential cause of brain abscess if the patient without any known premorbid history.

2226. Impact of Prior and Concomitant Antibacterial Therapy on Outcomes in the ASPECT-NP Randomized, Controlled Trial of Ceftolozane/Tazobactam (C/T) vs. Meropenem (MEM) in Patients with Ventilated Nosocomial Pneumonia (NP)

BackgroundNP is a frequent healthcare-acquired infection associated with high mortality; rising resistance rates among causative Gram-negative pathogens require new treatment options. In the randomized, controlled, double-blind, phase 3 ASPECT-NP trial, C/T (at double the initially approved dose) was noninferior to MEM for ventilated NP in both primary and key secondary endpoints. Here we evaluate the impact of prior and concomitant Gram-negative antibacterial therapy on outcomes in that trial.MethodsMechanically ventilated patients with ventilator-associated or hospital-acquired pneumonia were randomized 1:1 to 3 g C/T or 1 g MEM, both by 1-h IV infusion every 8 hours for 8–14 days. Patients could receive ≤24 hours of active antibacterial therapy within ≤72 hours prior to first dose; longer durations were permitted in case of prior treatment failure (i.e., signs and/or symptoms of the current episode of ventilated NP persisted/worsened despite ≥48 hours of treatment). At sites with MEM-resistant Pseudomonas aeruginosa rates ≥15%, patients could optionally receive up to 72 h of adjunctive empiric aminoglycoside (amikacin was recommended) until study drug susceptibility was confirmed. Primary and key secondary endpoints, respectively, were 28-d all-cause mortality and clinical response at test of cure (TOC; 7–14 days after the end of therapy) in the intent to treat (ITT) population (all randomized patients).ResultsIn the C/T arm, 285/362 (79%) ITT patients received prior systemic Gram-negative therapy and 103/362 (28%) received adjunctive aminoglycoside, compared with 288/364 (79%) and 112/364 (31%) patients, respectively, in the MEM arm. In the microbiologic ITT population, causative pathogens in patients failing prior therapy at the time of enrollment (C/T 15%, MEM 11%) were mainly Klebsiella spp (33%), P. aeruginosa (17%), Escherichia coli (14%), and Acinetobacter baumannii (8%). Mortality and cure rates were comparable between C/T and MEM regardless of receipt of prior systemic or adjunctive Gram-negative therapy (table).ConclusionPrior and adjunctive Gram-negative antibacterial therapy did not affect the relative efficacy of C/T (at the 3-g dose) vs. MEM in these high-risk patients with Gram-negative ventilated NP. Disclosures All authors: No reported disclosures.

Microbiology of Aspiration Pneumonia

The number of patients with pneumonia has been increasing as the population ages, and most fatal pneumonia cases are the elderly with aspiration pneumonia. Although aspiration pneumonia leads to poor short- and long-term prognosis, there have been no practical ways to diagnose it precisely. Persistent subclinical aspiration without any subjective symptoms is problematic in clinical practice in patients with aspiration pneumonia, and physicians can only use aspiration risks such as brain infarction to diagnose aspiration pneumonia. Anaerobes have been believed to be major causative pathogens in aspiration pneumonia, based on data from the 1970's. In relation to these data, Marik insisted that there is a possible overestimation of anaerobes because 1) the sampling of microbiologic specimens was in the late phase in the course of the illness, especially frequently after developing complications such as abscesses, necrotizing pneumonia, or empyema thoracis; 2) the organisms recovered by percutaneous transtracheal aspiration (PTA) sampling could have been contaminated by the aspiration of oropharyngeal flora during the PTA procedure or colonized in the trachea; and 3) many of the patients had chronic alcoholism or were under general anesthesia. In addition, 4) oral care was not common in the 1970s, and 5) the patients in these reports were relatively young. Molecular biological approaches using the 16S ribosomal RNA (rRNA) gene have recently been used, and have enabled us to detect more exact pathogens compared to conventional bacterial culture. Using the method with the detection of the 16S rRNA gene, we evaluated the bacterial phylotypes in bronchoalveolar lavage fluid in patients with aspiration pneumonia and found that oral streptococci were the most detected phylotypes (31.0%), while anaerobes were only 6.0%. Our results suggest that oral streptococci are important, and anaerobes may have been overestimated as causative pathogens in patients with aspiration pneumonia.

Detection of bacterial DNA from central venous catheter removed from patients by next generation sequencing: a preliminary clinical study

BackgroundCatheter-related infection (CRI) is one of the serious challenges in clinical practice. This preliminary clinical study aimed to examine whether next-generation sequencing (NGS) targeting 16S rDNA, which was PCR-amplified directly from the tip of a central venous catheter (CVC), can be used to identify causative pathogens in CRI, compared to the culture method.MethodsHospitalized patients, from whom a CVC had just been removed, were prospectively enrolled and divided into the CRI-suspected and routine removal groups. DNA was extracted from the sonication fluid of CVC specimens derived from patients. For analysis of bacterial composition by NGS, the V3–V4 fragments of bacterial 16S rDNA were PCR-amplified, followed by index PCR and paired-end sequencing on an Illumina MiSeq device. Conventional culture methods were also performed in the CRI-suspected group.ResultsOf CVCs collected from the 156 enrolled patients (114 men; mean age 65.6 years), a total of 14 specimens [nine out of 31 patients suspected with CRI and five out of 125 patients without infection symptoms (routine removal group)] were PCR-positive. In five patients with definite CRI, Staphylococcus was the most frequently detected genus by NGS (4/5 specimens), although no pathogens were detected by NGS in the one remaining specimen. The genera identified by NGS were consistent with those from conventional culture tests. There was high agreement between NGS and the culture method in the CRI-suspected group, with sensitivity and specificity values of 80.0% and 76.9%, respectively; meanwhile, the false-positive rate of NGS was as low as 4.0% in the routine removal group. Moreover, several genera, besides the genus identified by culture test, were detected in each patient with definite CRI and surgical site infection (SSI). Additionally, in one patient with SSI, Enterococcaceae were detected not only by NGS but also by abdominal abscess drainage culture.ConclusionsNGS targeting 16S rDNA was able to analyze the bacterial composition of CVC specimens and detect causative pathogens in patients with CRI and was therefore suggested as a promising diagnostic tool for CRI.

Expression Levels of Interferon Regulatory Factor 5 (IRF5) and Related Inflammatory Cytokines Associated with Severity, Prognosis, and Causative Pathogen in Patients with Community-Acquired Pneumonia.

BackgroundCommunity-acquired pneumonia (CAP) is a common disease with significant morbidity and mortality. Interferon regulatory factor 5 (IRF5), which induces type I interferons (IFNs) and cytokines such as interleukin (IL)-6, tumor necrosis factor (TNF)-α, IL-10, and interferon gamma-induced protein (IP)10, is a key transcription factor involved in controlling the expression of proinflammatory cytokines and responses to infection. Here, we carefully investigated the role of IRF5 in regulating immune responses to CAP.Material/MethodsQRT-PCR was used to detect the mRNA levels of IRF5, IL-6, IL-10, IP10, TNF-α, and IFN-α in the peripheral blood of 71 CAP patients and 31 healthy controls, as well as in the bronchoalveolar lavage cells of 20 patients with CAP and 23 patients with lung cancer (using samples from the unaffected lung). Flow cytometry was performed to detect the protein level of IRF5, and a CBA flex set was used to detect the levels of these cytokines in the volunteers.ResultsThe expression levels of IRF5 and its related cytokines were significantly increased in CAP patients compared with the controls. Additionally, IRF5, IL-6, IL-10, and IP10 levels were found to be related with the severity of CAP. Furthermore, the levels of IRF5 and IFN-α increased significantly in the early phase of pneumonia caused by influenza virus infection.ConclusionsIRF5 and its related inflammatory cytokines are associated with the severity, prognosis, and causative pathogen of CAP patients. This finding may provide new drug targets for the prevention and treatment of severe pneumonia caused by influenza virus.

Prior antimicrobial therapy duration influences causative pathogens identification in ventilator-associated pneumonia

ObjectiveTo determine whether prior antimicrobial therapy, divided in recent or current antibiotic treatment, influences the identification rate and/or the type of causative pathogens in patients with suspected episodes of ventilator-acquired pneumonia. DesignMonocentric retrospective study. SettingIntensive car unit in a universitary hospital. Patients230 episodes of ventilator-associated pneumonia with a Clinical Pulmonary Infection Score≥6 were retrospectively evaluated. Based on the antimicrobial treatment regimen, we defined 3 groups: the no antimicrobial treatment group (VAP is suspected in patients that has never received antibiotics during the last 90days), group 2: the current antimicrobial therapy (VAP is suspected under antimicrobial therapy) and group 3: the recent antimicrobial therapy (VAP is suspected whereas an antimicrobial treatment has been used during the last 90days but discontinued for >24h). InterventionBacteriologic analysis using a protected distal sampling with microscopic examination, culture and microbial identification using MALDI-TOF. Measurements and main resultsSuspected episodes of VAP were sorted as follow: 70 suspected episodes in the no antimicrobial therapy group, 106 suspected episodes in the current antimicrobial therapy group and 54 suspected episodes in the recent antimicrobial therapy group. The rate of positive culture was significantly lower in the current antimicrobial treatment group (group 2) when compared to the recent (group 3) and to the no antimicrobial treatment groups (group 1) (42%, 68% and 86%, respectively). When compared to the recent antibiotherapy group, we observed that current antibiotherapy was significantly associated with a higher rate of MDR positive culture, mainly due to higher rate of MDR Pseudomonas aeruginosa. ConclusionIn patients with a high probability of VAP, current but not recent antibiotic use is associated with a lower rate of positive culture with a higher proportion of MDR pathogens, mostly MDR Pseudomonas aeruginosa.

The Etiology of Pyogenic Vertebral Osteomyelitis and Evaluation of Biopsy Specimen Cultures in Hospitalized Patients

Identifying the causative pathogens in patients with pyogenic vertebral osteomyelitis is important for optimizing antibiotic therapy. Thus, we examined patient characteristics and investigated the efficacy of the combined use of blood culture and image-guided biopsy culture for identifying the causative pathogens of pyogenic vertebral osteomyelitis. A case series study was conducted in hospitalized patients who were diagnosed with pyogenic vertebral osteomyelitis using electronic medical records. Twenty-three patients who had undergone both blood culture and image-guided biopsy to determine the causative pathogens were identified. Detailed patient characteristics were identified, and the detection rate of a causative pathogen was 57% using either blood or biopsy specimen culture. By combining the results of each culture, the detection rate was increased to 83%. We described the detailed characteristics of patients with pyogenic vertebral osteomyelitis from whom both blood and biopsy specimen cultures were obtained. We found that the combined use of blood culture and biopsy specimen culture is useful for enhancing the detection of causative pathogens in patients with pyogenic vertebral osteomyelitis.

Severe invasive streptococcal infection by Streptococcus pyogenes and Streptococcus dysgalactiae subsp. equisimilis.

Streptococcus pyogenes, a group A Streptococcus (GAS), has been recognized as the causative pathogen in patients with severe invasive streptococcal infection with or without necrotizing fasciitis. In recent epidemiological studies, Streptococcus dysgalactiae subsp. equisimilis (SDSE) has been isolated from severe invasive streptococcal infection. Complete genome sequence showed that SDSE is the closest bacterial species to GAS, with approximately 70% of genome coverage. SDSE, however, lacks several key virulence factors present in GAS, such as SPE-B, the hyaluronan synthesis operon and active superantigen against human immune cells. A key event in the ability of GAS to cause severe invasive streptococcal infection was shown to be the acquisition of novel genetic traits such as phages. Strikingly, however, during severe invasive infection, GAS destroys its own covRS two-component system, which negatively regulates many virulence factor genes, resulting in a hyper-virulent phenotype. In contrast, this phenomenon has not been observed in SDSE. The present review describes the epidemiology of severe invasive streptococcal infection and the detailed pathogenic mechanisms of GAS and SDSE, emphasizing findings from their genome sequences and analyses of gene expression.

Effect of perioperative mupirocin and antiseptic body wash on infection rate and causative pathogens in patients undergoing cardiac surgery

Preoperative nasal mupirocin has been shown to reduce surgical site infections (SSIs) in patients undergoing cardiac surgery. We analyzed the effect of mupirocin plus antiseptic body wash on SSI rate and etiology. Prospective SSI surveillance was done for patients undergoing cardiac surgery before and after implementation of mupirocin nasal ointment and chlorhexidine/octenidine body wash. Overall SSI rate was 8.6% (81 out of 945) for the control and 6.9% (58 out of 842) for the intervention cohort (P=.19). In multivariable analysis, the study protocol was associated with an odds ratio of 0.61 (95% confidence interval, 0.41-0.91; P=.015) with regard to any SSI. This effect was exclusively due to a reduction in superficial SSIs and was observed both in patients with preoperative and postoperative treatment initiation. Coagulase-negative staphylococci (CoNS), the most commonly isolated pathogen, were found in 37% and 48% (P=.19) of patients in the control and the intervention cohort, respectively. CoNS were methicillin resistant in 69% of cases. Mupirocin and antiseptic body wash reduced the rate of superficial but not deep or organ/space SSIs. Postoperative patient treatment may be critical in reducing the risk for superficial SSI, presumably due to a reduction of bacterial skin load. A high proportion of SSI was due to methicillin-resistant CoNS and thus not covered by routine perioperative antimicrobial prophylaxis.

Clinical implications for patients treated inappropriately for community-acquired pneumonia in the emergency department

BackgroundCommunity-acquired pneumonia (CAP) is one of the most common infections presenting to the emergency department (ED). Increasingly, antibiotic resistant bacteria have been identified as causative pathogens in patients treated for CAP, especially in patients with healthcare exposure risk factors.MethodsWe retrospectively identified adult subjects treated for CAP in the ED requiring hospital admission (January 2003-December 2011). Inappropriate antibiotic treatment, defined as an antibiotic regimen that lacked in vitro activity against the isolated pathogen, served as the primary end point. Information regarding demographics, severity of illness, comorbidities, and antibiotic treatment was recorded. Logistic regression was used to determine factors independently associated with inappropriate treatment.ResultsThe initial cohort included 259 patients, 72 (27.8%) receiving inappropriate antibiotic treatment. There was no difference in hospital mortality between patients receiving inappropriate and appropriate treatment (8.3% vs. 7.0%; p = 0.702). Hospital length of stay (10.3 ± 12.0 days vs. 7.0 ± 8.9 days; p = 0.017) and 30-day readmission (23.6% vs. 12.3%; p = 0.024) were greater among patients receiving inappropriate treatment. Three variables were independently associated with inappropriate treatment: admission from long-term care (AOR, 9.05; 95% CI, 3.93-20.84), antibiotic exposure in the previous 30 days (AOR, 1.85; 95% CI, 1.35-2.52), and chronic obstructive pulmonary disease (AOR, 2.05; 95% CI, 1.52-2.78).ConclusionInappropriate antibiotic treatment of presumed CAP in the ED negatively impacts patient outcome and readmission rate. Knowledge of risk factors associated with inappropriate antibiotic treatment of presumed CAP could advance the management of patients with pneumonia presenting to the ED and potentially improve patient outcomes.

Serodiagnosis Using Microagglutination Assay during the Food-Poisoning Outbreak in Japan Caused by Consumption of Raw Beef Contaminated with Enterohemorrhagic Escherichia coli O111 and O157

A microagglutination (MA) assay to identify antibodies to Escherichia coli O111 and O157 was conducted in sera collected from 60 patients during a food-poisoning outbreak affecting 181 patients in Japan which was caused by the consumption of contaminated raw beef. Enterohemorrhagic E. coli (EHEC) O111:H8 and/or O157:H7 was isolated from the stools of some of the patients, but the total rate of positivity for antibodies to O111 (45/60, 75.0%) was significantly higher than that for antibodies to O157 (10/60, 16.7%). The MA titers of antibodies to O111 measured in patients with hemolytic-uremic syndrome and bloody diarrhea were higher than those measured in patients with only diarrhea. In patients from whose stool no isolates of E. coli O111 and O157 were obtained, the positive antibody detection rates were 12/19 (63.2%) for O111 and 2/19 (10.5%) for O157, and the MA titers of antibodies to O111 measured were higher than those to O157. Similarly, the MA titers of antibodies to O111 were significantly higher than those to O157, regardless of the other groups, including groups O111, O111 and O157, and O157. These serodiagnosis results suggest that EHEC O111:H8 stx2 played a primary role in the pathogenesis of this outbreak. Furthermore, our findings suggest that the isolates from the patients' stool specimens were not always the major causative pathogen in patients with multiple EHEC infections, because the sera from patients from whose stools only O157 was isolated were positive for antibodies to O111. Measuring antibodies to E. coli O antigen is helpful especially in cases with multiple EHEC infections, even with a non-O157 serotype.