Enterococcal Infections Research Articles

2205. Utilization of guiding comments imbedded within culture results to improve antimicrobial prescribing for enterococcal urinary tract infections in the ambulatory setting

Abstract Background Evaluate outcomes associated with utilizing guiding comments imbedded within the electronic health record’s (EHR) culture result to decrease the inappropriate use of cephalosporins in enterococcal urinary tract infections. Methods Data collected retrospectively from a regional health system from 02/01/22 to 02/28/23. Inclusion criteria was urine culture positive for enterococcus and active cephalosporin order. Exclusion criteria was cephalosporin treatment prescribed for a non-enterococcal organism and age less than 18 years. Patients were evaluated 6 months pre- and post-implementation of a microbiology comment added to streptococcus gamma and enterococcal cultures: “Enterococcus sp. are resistant to cephalosporins.” The primary outcome was rate of inappropriate prescribing of cephalosporins in enterococcal urinary tract infections in the ambulatory care setting. The secondary outcome was rate of 30-day follow-up visits required pre- and post-implementation of guiding comment. Follow-up was defined as either ambulatory visit, telephone visit, emergency department admission, or inpatient admission. Chi-Squared statistical test was utilized to compare nominal data. Results 93 patients were not included based on inclusion and exclusion criteria. 141 patients in the pre group and 146 patients in the post group were analyzed. After guiding comment implementation, the incidence of inappropriate treatment continuation decreased from 67.4% to 43.8% (RRR=35%, p=0.001). Follow up events included patient encounters related to urinary symptoms such as emergency department admissions, inpatient admission, ambulatory visits, and telephone encounters. Total patients requiring follow-up decreased from 44.7% (63/141) to 26.0% (38/146); 41.8% relative risk reduction (p = 0.001). Conclusion Providers assume enterococcus sensitivity to ampicillin equates to sensitivity to all beta-lactams. The implementation of guiding comments results significantly reduced the inappropriate use of cephalosporins to treat enterococcal urinary tract infections. Total follow-up visits were also significantly reduced which has the potential to improve patient experience. Enterococcal guiding comments should be implemented at heath care facilities when possible. Disclosures All Authors: No reported disclosures

Antimicrobial Activity of Ceragenins against Vancomycin-Susceptible and -Resistant Enterococcus spp.

Ceragenins (CSAs) are a new class of antimicrobial agents designed to mimic the activities of endogenous antimicrobial peptides. In this study, the antibacterial activities of various ceragenins (CSA-13, CSA-44, CSA-90, CSA-131, CSA-138, CSA-142, and CSA-192), linezolid, and daptomycin were assessed against 50 non-repeated Enterococcus spp. (17 of them vancomycin-resistant Enterococcus-VRE) isolated from various clinical specimens. Among the ceragenins evaluated, the MIC50 and MIC90 values of CSA-44 and CSA-192 were the lowest (2 and 4 μg/mL, respectively), and further studies were continued with these two ceragenins. Potential interactions between CSA-44 or CSA-192 and linezolid were tested and synergistic interactions were seen with the CSA-192-linezolid combination against three Enterococcus spp., one of them VRE. The effects of CSA-44 and CSA-192 on the MIC values of vancomycin were also investigated, and the largest MIC change was seen in the vancomycin-CSA-192 combination. The in vivo effects of CSA-44 and CSA-192 were evaluated in a Caenorhabditis elegans model system. Compared to no treatment, increased survival was observed with C. elegans when treated with ceragenins. In conclusion, CSA-44 and CSA-192 appear to be good candidates (alone or in combination) for the treatment of enterococcal infections, including those from VRE.

Molecular epidemiology, phenotypic and genomic characterization of antibiotic-resistant enterococcal isolates from diverse farm animals in Xinjiang, China

Multidrug-resistant (MDR) bacteria in farm environments can be transferred to humans through the food chain and occupational exposure. Enterococcus infections caused by linezolid resistant enterococci (LRE) are becoming more challenging to treat as their resistance to antibiotics intensifies. Therefore, this study investigated the molecular epidemiology, phenotypic and genomic characterization of enterococci in seven species of farm animals (sheep, chicken, swine, camel, cattle, equine, pigeon) anal swab from Xinjiang, China by agar dilution method, polymerase chain reaction (PCR), whole-genome sequencing (WGS) and bioinformatics analysis. A total of 771 samples were collected, 599 (78 %) were contaminated with Enterococcus spp., among which Enterococcus faecalis (350/599) was dominant. Antimicrobial susceptibility testing showed that high resistance was observed in rifampicin (80 %), tetracycline (71 %), doxycycline (71 %), and erythromycin (69 %). The results of PCR showed the highest prevalent antibiotic resistance genes (ARGs) were aac(6′)-aph(2″) (85 %), followed by tet(M) (73 %), erm(B) (62 %), and aph(3′)-IIIa (61 %). Besides, 29 optrA-carrying E. faecalis isolates belonging to 13 STs (including 3 new alleles) were detected, with ST714 (31 %, 9/29) being the dominant ST type. The phylogenetic tree showed that optrA-carrying E. faecalis prevalent in the intensive swine farm is mainly caused by clonal transmission. Notably, optrA gene in Enterococcus spp. isolate from camel was first characterized here. WGS of E. faecalis F109 isolate from camel confirmed the colocalization of optrA with other five ARGs in the same plasmid (pAFL-109F). The optrA-harboring genetic context is IS1216E-fexA-optrA-erm(A)-IS1216E. This study highlights the prevalence of MDR Enterococcus (≥88 %) and four ARGs (≥75 %) in swine (intensive farming), cattle (commercial farming), and chickens (backyard farming) are high and also highlights that optrA-carrying E. faecalis of farm animals incur a transmission risk to humans through environment, food consumption and others. Therefore, antibiotic-resistant bacteria (ARB) monitoring and effective control measures should be strengthened and implemented in diverse animals.

The Synergistic Activity of Rhamnolipid Combined with Linezolid against Linezolid-Resistant Enterococcus faecium.

Enterococci resistance is increasing sharply, which poses a serious threat to public health. Rhamnolipids are a kind of amphiphilic compound used for its bioactivities, while the combination of nontraditional drugs to restore linezolid activity is an attractive strategy to treat infections caused by these pathogens. This study aimed to investigate the activity of linezolid in combination with the rhamnolipids against Enterococcus faecium. Here, we determined that the rhamnolipids could enhance the efficacy of linezolid against enterococci infections by a checkerboard MIC assay, a time-kill assay, a combined disk test, an anti-biofilm assay, molecular simulation dynamics, and mouse infection models. We identified that the combination of rhamnolipids and linezolid restored the linezolid sensitivity. Anti-biofilm experiments show that our new scheme can effectively inhibit biofilm generation. The mouse infection model demonstrated that the combination therapy significantly reduced the bacterial load in the feces, colons, and kidneys following subcutaneous administration. This study showed that rhamnolipids could play a synergistic role with linezolid against Enterococcus. Our combined agents could be appealing candidates for developing new combinatorial agents to restore antibiotic efficacy in the treatment of linezolid-resistant Enterococcus infections.

Enterococcal Membrane Vesicles as Vaccine Candidates.

Enterococcus faecium is a leading cause of nosocomial infections, particularly in immunocompromised patients. The rise of multidrug-resistant E. faecium, including Vancomycin-Resistant Enterococci (VRE), is a major concern. Vaccines are promising alternatives to antibiotics, but there is currently no vaccine available against enterococci. In a previous study, we identified six protein vaccine candidates associated with extracellular membrane vesicles (MVs) produced by nosocomial E. faecium. In this study, we immunized rabbits with two different VRE-derived MV preparations and characterized the resulting immune sera. Both anti-MV sera exhibited high immunoreactivity towards the homologous strain, three additional VRE strains, and eight different unrelated E. faecium strains representing different sequence types (STs). Additionally, we demonstrated that the two anti-MV sera were able to mediate opsonophagocytic killing of not only the homologous strain but also three unrelated heterologous VRE strains. Altogether, our results indicate that E. faecium MVs, regardless of the purification method for obtaining them, are promising vaccine candidates against multidrug-resistant E. faecium and suggest that these naturally occurring MVs can be used as a multi-antigen platform to elicit protective immune responses against enterococcal infections.

Bacteraemia caused by non-faecalis and non-faecium Enterococcus species—a retrospective study of incidence, focus of infection, and prognosis

Background/aimEnterococcus faecalis and Enterococcus faecium cause human infections including bacteraemia and infective endocarditis (IE). Only few studies describing non-faecalis and non-faecium Enterococcus (NFE) infections have been conducted. We aimed to describe the incidence, prognosis, and focus of infection of bacteraemia with NFE.MethodsThis retrospective population-based study included all episodes of patients having a blood culture with growth of NFE between 2012 and 2019 in Region Skåne, Sweden. Information was collected from medical records. Episodes of bacteraemia caused by NFE were compared to episodes of bacteraemia caused by E. faecalis and E. faecium.ResultsDuring the study period, 136 episodes with NFE bacteraemia were identified corresponding to an incidence of NFE bacteraemia of 16 cases per 1,000,000 person-years among adults. Enterococcus casseliflavus (n=45), Enterococcus gallinarum (n=34), and Enterococcus avium (n=29) were the most common species. The most common foci of infection were biliary tract infections (n=17) followed by gastrointestinal infections (n=7). Urinary tract infections were not commonly caused by NFE (n=1), and no episodes of IE were caused by NFE. Polymicrobial bacteraemia was more common with NFE (73%) than with E. faecalis (35%) and E. faecium (42%). Community acquired infections were more common in bacteraemia with NFE compared to E. faecium. 30- and 90-day survival rates were 76% and 68%, respectively, and recurrent NFE bacteraemia was seen after 3% of the episodes.ConclusionBacteraemia caused by NFE is rare and is often polymicrobial. Biliary tract focus is common in NFE bacteraemia whereas IE and urinary tract focus are uncommon.

Examining Antimicrobial Resistance in Enterococcus Species: A Single-Center Cross-Sectional Study

Background: Antimicrobial resistance in Enterococcus species is a growing global concern. These bacteria, commonly found in the human gut, have resisted multiple antibiotics, making infections harder to treat. This poses a significant challenge for healthcare as it limits treatment options and highlights the urgent need for responsible antibiotic use and the development of new therapies. Aim of the study: The study aimed to determine the antimicrobial resistance pattern of Enterococcus Species at a tertiary care hospital in Bangladesh. Methods: This cross-sectional research occurred at Sample collected from deferent laboratories situated in rangpur and test/research perform, Department of Microbiology in prime institute of science and medical technology (PRISMET), Rangpur During March’ 2022 to March’ 2023. It spanned one year from [start date] to [end date]. The primary goal was to evaluate the antimicrobial susceptibility patterns of enterococci. Throughout the study, 1,450 samples were collected from various sources, including urine, blood, pus, swabs, and fluids. However, only 62 Enterococci isolates were successfully obtained. Standard microbiological protocols, such as microscopy and culture, were rigorously followed during sample processing. All clinical samples received at the Microbiology laboratory during the study were considered for inclusion. Data analysis was conducted using Microsoft Excel and presented with tables and graphs, while SPSS was employed for statistical analysis. Result: The study population primarily consisted of patients aged 36-75 (77.42%), averaging 52.01 years. Gender distribution was skewed towards males (59.68%). Enterococcus spp. They have dominated the microbial species (64.52%), with E. faecalis (14.52%) and E. faecium (11.29%) being prevalent. Urine samples were the most common (66.13%), followed by pus (11.29%) and swab (9.68%). Antibiotic susceptibility analysis showed varying results, with amoxicillin being sensitive in 87.10% of cases, while Cefixime, Ceftazidime, Ceftriaxone, and Cefotaxime exhibited over 96% resistance. Conclusion: This study highlights the rise of antimicrobial resistance (AMR) in Enterococcus species at a Bangladeshi tertiary care hospital. Once harmless, these bacteria now pose a severe risk to public health. Our research shows that E. faecalis and E. faecium have become resistant to many common antibiotics, particularly cephalosporins, urging immediate antibiotic stewardship and infection control. To combat this global health threat, we must explore novel treatments and employ a multidisciplinary approach to protect patients and healthcare systems from Enterococcus infections.

Are enterococcal bloodstream infections an independent risk factor for a poorer 5-year survival or just a marker for severity of illness?-The Munich multicentric enterococci cohort.

The present study provides a substantial contribution to literature, showing that patients with enterococcal bloodstream infections (BSI) have a lower survival rate than those with Escherichia coli (E. coli) bloodstream infections after adjusting for 17 limiting prognostic factors and excluding patients with a limited life expectancy [metastatic tumor disease, Charlson Comorbidity Index (CCI) (greater than or equal to) 5]. This difference in the 5-year long-term survival was mainly driven by Enterococcus faecium (ECFM) bloodstream infections, with vancomycin resistance not being a significant contributing factor. Our findings imply that E. faecium bloodstream infections seem to be an independent risk factor for poor long-term outcomes. As such, future research should confirm this relationship and prioritize investigating its causality through prospective studies.

Identification of Vancomycin Resistant Enterococcus Genes in Clinical Isolates

Vancomycin resistant enterococci (VRE) nosocomial diseases are rapidly spreading across the world. To treat these diseases is becoming a great challenge due to antibiotic resistance. The present study was aimed to estimate the prevalence of vancomycin resistant enterococci and to find out genes responsible for causing vancomycin resistance. One hundred different blood, wound and urine samples were collected from hospitalized patients at tertiary care health hospital, Lahore. On the basis of colony morphology, isolates of Enterococci were identified, Gram staining and biochemical tests including catalase test, Bile esculin test, growth in 6.5% NaCl, litmus milk reduction were performed. All the clinical isolates were checked for vancomycin resistant and 15% of all the samples were vancomycin resistant. Polymerase chain reaction (PCR) was performed for vancomycin resistance, enterococcal isolates to identify van genes responsible for resistance. In our study the presence of vanA gene was found in all 15 vancomycin resistant samples. vanB gene was not detected in any of the sample. The study highlights the increased VRE prevalence in clinicalisolates obtained from local hospital. The presence of vanA gene in all resistant samples is suggestive of its role as resistant gene. On the basis of these results there is an urgent need of establishing a rational antibiotic use policy for better management of enterococcal infections.

Antibiotic treatment of choice for urinary sepsis associated with ureteral lithiasis in Chile. Multicenter study

Inadequate antibiotic coverage in septic patients is associated with higher morbidity and mortality. This multicentric study reports antibiotic susceptibility in patients with ureterolithiasis-associated urosepsis, aiming to propose an optimal empirical therapy for this disease in the Chilean population. The prospective cohort study included patients from 7 Chilean hospitals who presented with ureterolithiasis and met sepsis criteria. We analyzed demographic data, vital signs at admission, and microbiological and radiological exams. We used descriptive statistics for the analysis of collected data. Initially, the study included 119 patients; 52 met the inclusion criteria. 77% were female, with a mean age of 52. 100% of the cohort had a urine culture taken at admission, whereas 48,7% had blood cultures. Escherichia Coli was the most common microorganism (73%), followed by Proteus Mirabilis (9.6%) and Klebsiella Pneumoniae (3.9%). Only two patients presented gram-positive pathogens. 100% of gram-negative bacteria were sensible to amikacin. The microorganisms found in our cohort were similar to those in international reports. Since the highest level of susceptibility was for amikacin, we propose its use as empirical therapy for urosepsis associated with ureterolithiasis in Chile. It is always necessary to consider the potential nephrotoxic effects of amikacin. An association of beta-lactams and glycopeptides should be considered in patients with risk factors for enterococcal infections.

Colonizer to Pathogen: A review on Enterococcal urinary tract infections

Abstract Enterococcus species has been historically known as part of the commensal flora of the normal human alimentary tract. Implicated in a wide array of illnesses encompassing bloodstream infections, urinary tract infections, wound infections as well as intra-abdominal infections, it has been rapidly emerging as a pathogen of interest owing to its propensity to acquire multidrug resistance. Due to the high antibiotic pressure in healthcare settings and salient intrinsic resistance to commonly used classes of antimicrobials, Enterococcus selectively proliferates in nosocomial settings. Their hardy nature and ability to resist a wide array of disinfectants enable them to proliferate on surfaces as well as provide for efficient transmission in hospital settings. Since Urinary tract infection (UTI) is one of the commonest infections caused by Enterococcus species. We attempt to comprehensively overview the paradigm shift of this erstwhile colonizer to one of the common uropathogen in hospital and community settings.

Analysis of the main bioactive compounds from Ocimum basilicum for their antimicrobial and antioxidant activity.

The interest in bioactives especially from botanicals to treat vancomycin-resistant enterococcal (VRE) infections is increased. Many species of Ocimum have a long history in folk medicinal and food industries. Nevertheless, their bioactive compounds remain unexplored. This study is aimed to assess the antimicrobial and antioxidant activity of basil leaf extract prepared using ethanol, methanol, and water. The ethanol and methanol extract have all the phytochemicals (alkaloids, flavonoids, phenolic compounds, tannins, saponins, quinones, carbohydrates, and proteins) except steroids and terpenoids. In addition to steroids and terpenoids, tannin was also absent in the aqueous extract. Total phenolic and flavonoid content was high in ethanol and followed by methanol and aqueous extract. Similarly, ethanol and methanol extract showed strong antimicrobial activity against VRE and MTCC strains at a concentration of 20mg/mL than aqueous extract. Among the 10 indicators, Staphylococcus aureus is highly susceptible to ethanol extract at a concentration of 8mg/mL and followed by other MTCC strains. Vancomycin-resistant enterococci pathogens were inhibited at the minimum inhibitory concentration of 14, 16, and 20mg/mL of ethanol, methanol, and aqueous extract. Further, on the basis of determining the absorbing material (nucleic acid and protein) at 260nm and scanning electron microscopic, it was confirmed that the loss of cell membrane integrity and cell membrane damage were the effective mechanisms of plant extract antimicrobial activity. All three solvents have shown remarkable antioxidant activity. Gas chromatography-mass spectrometry analysis of basil leaves ethanol extract identified 19 compounds with various therapeutic and food applications.

Vancomycin-resistant enterococcus bloodstream infection successfully managed with oritavancin and fosfomycin as sequential treatment

Bloodstream infections caused by vancomycin-resistant enterococci are increasingly reported and a consensus therapy does not exist. Oritavancin has shown good antimicrobial activity against VRE, but its use is mainly limited to skin, soft tissue, and/or bone infections. Fosfomycin is increasingly used for enterococcal infections (including bloodstream infections and endocarditis) as a partner drug given its anti-biofilm and synergistic properties. Recently in vitro and in vivo synergism between oritavancin and fosfomycin against VRE isolates has been demonstrated. Herein we report the case of a hematologic patient with a VRE bloodstream infection successfully treated with oritavancin and fosfomycin as sequential treatment.

Antibiotic choices among healthcare professionals for enterococcal bacteremia with patterns of resistance and risk factors of mortality, in settings of poor antibiotic stewardship program — a five-year retrospective cohort study

BackgroundEnterococcal bacteremia has become prevalent in the recent decade, especially in hospitalized patients. Moreover, the rise in resistance patterns against antibiotic drugs regarding enterococci infection, such as cephalosporins, ampicillin and vancomycin, is prevailing. The major driving force behind this is the incongruous use of antibiotics with a minor contribution from environmental stressors which calls for vigilant and prudent administration of evidence-based antibiotics.MethodsA retrospective study was conducted from January 1 2017 until December 31 2021, at the tertiary care center, Dr Ziauddin Hospital in Karachi, Pakistan.ResultsOur research revealed ampicillin resistance in 87 (63.5%), with an estimated 25 (18.8%) mortality. Male gender 19 (76%) and vancomycin resistance 13 (52%) were associated with increased mortality. Furthermore, appropriate antibiotic therapy reduced the risk of death compared with inappropriate and excessive use of antibiotics 10 (40%) vs. 15 (60%) vs. 20 (80%) respectively. Targeted therapy with amoxicillin/clavulanic acid was associated with lower mortality 1 (4%) and higher discharge rates 34 (32.1%). On Kaplan-Meier survival, targeted therapy with amoxicillin/clavulanic acid was associated with shorter hospital stays and prolonged survival. UTI was found as the most common source of enterococcal bacteremia 57 (41.6%), followed by respiratory 21 (15.3%) and intra-abdominal 13 (9.5%). In 26 (19%) patients, no identifiable source of infection was found.ConclusionVancomycin resistance and male gender were found independent risk factors for mortality. The use of inappropriate antibiotics significantly increases mortality in these patients. The appropriate antibiotic therapy reduces the risk of death. Furthermore, overuse of antibiotics didn’t reduce mortality; instead increased the financial burden and chances of developing multi-drug resistant strains of other organisms by increasing hospital stays of patients.

Antibiotic Resistance and Susceptibility Profile, with Biofilm Forming Potential Of Clinically Isolated Enterococcus Specie from Blood and Urine Samples

Enterococcus spp. is Gram-positive cocci bacteria among the normal flora in human intestine. Common species are Enterococcus fecalis and Enterococcus faecium. They work as probiotics and help in digestion and immune system modulation. Enterococci are opportunistic pathogens and can cause nosocomial infections. Biofilm is one of the factors that facilitate the antibiotic resistance, which is complex EPS (exopolysaccharides) structure surrounding microbial cells, making them resistant from antimicrobial treatments. Due to acquisition of different virulence factors and resistance from antibiotics, infections of Enterococcus spp., have increased. In this study antibiotic resistance and sensitivity profile with their ability to form biofilm, has been determined. Human blood and urine samples were taken from Memon Medical Hospital Karachi. Culture and sensitivity test was performed for the major groups of antibiotics used for treating enterococcal infections with analysis of biofilm formation. Highest resistance was observed against the antibiotic levofloxacin 90% and all organisms were sensitive from linezolid 100%. Overall organisms were resistance from one and more antibiotics. All organisms were able to form biofilms as well. Antibiotic resistance has become an alarming challenge for the health care globally. Enterococcal resistance from major groups of antibiotics for their treatment has increased the rate of nosocomial infections.

Multisite Phosphorylation Regulates GpsB Function in Cephalosporin Resistance of Enterococcus faecalis

Enterococci are normal human commensals and major causes of hospital-acquired infections. Enterococcal infections can be difficult to treat because enterococci harbor intrinsic and acquired antibiotic resistance, such as resistance to cephalosporins. In Enterococcus faecalis, the transmembrane kinase IreK, a member of the bacterial PASTA kinase family, is essential for cephalosporin resistance. The activity of IreK is boosted by the cytoplasmic protein GpsB, which promotes IreK autophosphorylation and signaling to drive cephalosporin resistance. A previous phosphoproteomics study identified eight putative IreK-dependent phosphorylation sites on GpsB, but the functional importance of GpsB phosphorylation was unknown. Here we used genetic and biochemical approaches to define three sites of phosphorylation on GpsB that functionally impact IreK activity and cephalosporin resistance. Phosphorylation at two sites (S80 and T84) serves to impair the ability of GpsB to activate IreK in vivo, suggesting phosphorylation of these sites acts as a means of negative feedback for IreK. The third site of phosphorylation (T133) occurs in a segment of GpsB termed the C-terminal extension that is unique to enterococcal GpsB homologs. The C-terminal extension is highly mobile in solution, suggesting it is largely unstructured, and phosphorylation of T133 appears to enable efficient phosphorylation at S80 / T84. Overall our results are consistent with a model in which multisite phosphorylation of GpsB impairs its ability to activate IreK, thereby diminishing signal transduction through the IreK-dependent pathway and modulating phenotypic cephalosporin resistance.

Impact of a new hospital with close to 100% single-occupancy rooms on environmental contamination and incidence of vancomycin-resistant Enterococcus faecium colonization or infection: a genomic surveillance study

Vancomycin-resistant Enterococcus faecium (VRE) is a leading cause of nosocomial infection, driven by its ability to spread between patients and persist in the hospital environment. To investigate the impact of a long-established cardiothoracic hospital moving to new premises with close to 100% single-occupancy rooms on the rates of environmentalcontamination and infection or colonization by VRE. Prospective environmental surveillance for VRE was conducted at five time-points between April and November 2019, once in the original building, and four times in the new building. Incidence rate ratios (IRRs) of VRE infection/colonization were determined for the one-year period before and after the hospital move, and compared to a nearby hospital. In the original location, the first environmental screen found 29% VRE positivity. The following four screens in the new location showed a significant reduction in positivity (1-6%; P<0.0001). The VRE infection/colonization rates were halved in the new location (IRR: 0.56; 95% confidence interval: 0.38-0.84), compared to the original location,contrasting with an increase in a nearby hospital (1.62; 1.17-2.27) over the same time-period. Genomic analysis of the environmental isolates was consistent with reduced transmission in the new hospital. The use of single-occupancy rooms was associated with reducedenvironmental contamination with VRE, and lower transmission and isolation of VRE from clinical samples. The cost-effectiveness of single-occupancy room hospitals in reducing healthcare-associated infections should be reassessed in the context of operational costs of emerging pandemic and increasing antimicrobial resistance threats.

Prevalence of Enterococcal Urinary Tract Infections With Positive Nitrites in Urinalysis in Pediatric Patients With High-Risk for Enterococcal Infections.

Enterococcus is a relatively uncommon pathogen that causes urinary tract infections (UTIs) in healthy children. Most enterococcal infections occur in patients with risk factors such as anatomical or functional urinary tract anomalies, also known as CAKUT (congenital anomalies of kidney and urinary tract). Children who are suspected of having UTIs and who have certain risk factors are often treated specifically for enterococcal infection as part of their empiric regimen. Our primary objective was to determine the prevalence of enterococcal UTIs among high-risk children, and specifically among those with positive nitrite tests, with the goal of avoiding treatment with specific anti-enterococcal agents. This retrospective study included all the episodes of UTI treated at a tertiary pediatric center during 2010 to 2018. The data collected from medical records included nephrological and urological risk factors, nitrite status, and isolated pathogens. Of 931 episodes of UTI, 467 (50%) were considered high-risk. In all, 24 of the latter had Enterococcus as a single pathogen; 23 (96%) of these occurred in patients with negative nitrites in the first urine dipstick taken. The sole patient with high-risk factors, a positive nitrite test and coexisting enterococcal UTI had a history of previous enterococcal UTIs. In pediatric patients with nephrological and urological risk factors, who have positive nitrites in urinalysis, the risk for enterococcal UTI appears substantially low. Therefore, in this context, specific anti-enterococcal empirical antibiotic therapy may be unnecessary.

Carbonic Anhydrase Inhibition as a Target for Antibiotic Synergy in Enterococci.

Enterococcus faecalis is a hospital-associated opportunistic pathogen that can cause infections with high mortality, such as infective endocarditis. With an increasing occurrence of multidrug-resistant enterococci, there is a need for alternative strategies to treat enterococcal infections. We isolated a gentamicin-hypersusceptible E. faecalis strain from a patient with infective endocarditis that carried a mutation in the alpha-carbonic anhydrase (α-CA) and investigated how disruption of α-CA sensitized E. faecalis to killing with gentamicin. The gentamicin-hypersusceptible α-CA mutant strain showed increased intracellular gentamicin uptake in comparison to an isogenic strain encoding full-length, wild-type α-CA. We hypothesized that increased gentamicin uptake could be due to increased proton motive force (PMF), increased membrane permeability, or both. We observed increased intracellular ATP production in the α-CA mutant strain, suggesting increased PMF-driven gentamicin uptake contributed to the strain's gentamicin susceptibility. We also analyzed the membrane permeability and fatty acid composition of isogenic wild-type and α-CA mutant strains and found that the mutant displayed a membrane composition that was consistent with increased membrane permeability. Finally, we observed that exposure to the FDA-approved α-CA inhibitor acetazolamide lowered the gentamicin MIC of eight genetically diverse E. faecalis strains with intact α-CA but did not change the MIC of the α-CA mutant strain. These results suggest that α-CA mutation or inhibition increases PMF and alters membrane permeability, leading to increased uptake of gentamicin into E. faecalis. This connection could be exploited clinically to provide new combination therapies for patients with enterococcal infections. IMPORTANCE Enterococcal infections can be difficult to treat, and new therapeutic approaches are needed. In studying an E. faecalis clinical strain from an infected patient, we found that the bacteria were rendered hypersusceptible to aminoglycoside antibiotics through a mutation that disrupted the α-CA. Our follow-on work suggested two different ways that α-CA disruption causes increased gentamicin accumulation in E. faecalis: increased proton motive force-powered uptake and increased membrane permeability. We also found that a mammalian CA inhibitor could sensitize a variety of E. faecalis strains to killing with gentamicin. Given that mammalian CA inhibitors are frequently used to treat conditions such as glaucoma, hypertension, and epilepsy, our findings suggest that these "off-the-shelf" inhibitors could also be useful partner antibiotics for the treatment of E. faecalis infections.

Enterococcus Species: A Systemic Review

Enterococci are gram-positive facultative anaerobes, these are commensals in the intestinal system of numerous animals, including humans. They affect hospitalized patients and cause nosocomial infections, respiratory infections, endocarditis, wound infections, UTIs, and other enterococcal infections. This discovery can be explained by hemolysin, gelatinase, aggregation substances, hyaluronidase, capsular polysaccharides, and cell wall carbohydrate. Various enterococcal spp. include Enterococcus avium Vancomycin resistance was acquired by enterococci throughout the antibacterial spectrum, primary antibiotic used regimen based on dual β lactams and aminoglycosides.