Risk factors for colonization with extended-spectrum cephalosporin-resistant and carbapenem-resistant Enterobacterales among hospitalized patients in Guatemala: An Antibiotic Resistance in Communities and Hospitals (ARCH) study

Objectives

The spread of extended-spectrum cephalosporin-resistant Enterobacterales (ESCrE) and carbapenem-resistant Enterobacterales (CRE) has resulted in increased morbidity, mortality, and health care costs worldwide. To identify the factors associated with ESCrE and CRE colonization within hospitals, we enrolled hospitalized patients at a regional hospital located in Guatemala.

Methods

Stool samples were collected from randomly selected patients using a cross-sectional study design (March-September, 2021), and samples were tested for the presence of ESCrE and CRE. Hospital-based and household variables were examined for associations with ESCrE and CRE colonization using lasso regression models, clustered by ward (n = 21).

Results

A total of 641 patients were enrolled, of whom complete data sets were available for 593. Colonization with ESCrE (72.3%, n = 429/593) was negatively associated with carbapenem administration (odds ratio [OR] 0.21, 95% confidence interval [CI] 0.11-0.42) and positively associated with ceftriaxone administration (OR 1.61, 95% CI 1.02-2.53), as was reported hospital admission within 30 days of the current hospitalization (OR 2.84, 95% CI 1.19-6.80). Colonization with CRE (34.6%, n = 205 of 593) was associated with carbapenem administration (OR 2.62, 95% CI 1.39-4.97), reported previous hospital admission within 30 days of current hospitalization (OR 2.58, 95% CI 1.17-5.72), hospitalization in wards with more patients (OR 1.05, 95% CI 1.02-1.08), hospitalization for ≥4 days (OR 3.07, 95% CI 1.72-5.46), and intubation (OR 2.51, 95% CI 1.13-5.59). No household-based variables were associated with ESCrE or CRE colonization in hospitalized patients.

Conclusion

The hospital-based risk factors identified in this study are similar to what has been reported for risk of health care-associated infections, consistent with colonization being driven by hospital settings rather than community factors. This also suggests that colonization with ESCrE and CRE could be a useful metric to evaluate the efficacy of infection and prevention control programs in clinics and hospitals.

The colonization of Penicillium oxalicum SL2 on rice root surface increased Pb interception capacity of iron plaque and decreased Pb uptake by roots

The exploration of microbial resources to reduce Pb accumulation in rice attracted great attention. In this study, we found Penicillium oxalicum SL2, a Pb-tolerant strain with good capability of dissolving phosphorus and stabilizing Pb in soil, was able to colonize on the root surface of rice seedlings without additional carbon sources, and promoted the secretion of metabolites related to amino acid metabolism, organic acid metabolism, signal transduction and other pathways in rhizosphere exudates, in which the secretion of oxalate increased by 47.7 %. However, P. oxalicum SL2 increased Fe(II) proportion and Fe availability on the root surface, resulting in iron plaque content decrease. Moreover, by converting root surface Pb from Pb-Fe state to PbC2O4 and Pb-P compounds, P. oxalicum SL2 increased Pb intercept capacity of iron plaque by 118.0 %. Furthermore, P. oxalicum SL2 regulated element distribution on the root surface, and reduced the relative content of Pb on the maturation zone of root tip, which was conducive to reducing Pb uptake by apoplastic pathway and the risk of Pb accumulation in root system. Our findings further revealed the interaction between P. oxalicum SL2 and rice root, providing a theoretical basis for the development and application of microbial agents in Pb-contaminated farmland.

Oxidative stress, biofilm-formation and activity responses of P. aeruginosa to microplastic-treated sediments: Effect of temperature and sediment type

Climate change and plastic pollution are the big environmental problems that the environment and humanity have faced in the past and will face in many decades to come. Sediments are affected by many pollutants and conditions, and the behaviors of microorganisms in environment may be influenced due to changes in sediments. Therefore, the current study aimed to explore the differential effects of various microplastics and temperature on different sediments through the metabolic and oxidative responses of gram-negative Pseudomonas aeruginosa. The sediments collected from various fields including beaches, deep-sea discharge, and marine industrial areas. Each sediment was extracted and then treated with various microplastics under different temperature (-18, +4, +20 and 35 °C) for seven days. Then microplastics were removed from the suspension and microplastic-exposed sediment samples were incubated with Pseudomonas aeruginosa to test bacterial activity, biofilm, and oxidative characteristics. The results showed that both the activity and the biofilm formation of Pseudomonas aeruginosa increased with the temperature of microplastic treatment in the experimental setups at the rates between an average of 2-39 % and 5-27 %, respectively. The highest levels of bacterial activity and biofilm formation were mainly observed in the beach area (average rate +25 %) and marine industrial (average rate +19 %) sediments with microplastic contamination, respectively. Moreover, oxidative characteristics significantly linked the bacterial activities and biofilm formation. The oxidative indicators of Pseudomonas aeruginosa showed that catalase and glutathione reductase were more influenced by microplastic contamination of various sediments than superoxide dismutase activities. For instance, catalase and glutathione reductase activities were changed between -37 and +169 % and +137 to +144 %, respectively; however, the superoxide dismutase increased at a rate between +1 and + 21 %. This study confirmed that global warming as a consequence of climate change might influence the effect of microplastic on sediments regarding bacterial biochemical responses and oxidation characteristics.

Development of a risk prediction model for subsequent infection after colonization with carbapenem-resistant Enterobacterales: a retrospective cohort study

BACKGROUND

Colonization of carbapenem-resistant Enterobacterale (CRE) is considered as one of vital preconditions for infection, with corresponding high morbidity and mortality. It is important to construct a reliable prediction model for those CRE carriers with high risk of infection.

METHODS

A retrospective cohort study was conducted in two Chinese tertiary hospitals for patients with CRE colonization from 2011 to 2021. Univariable analysis and the Fine-Gray sub-distribution hazard model were utilized to identify potential predictors for CRE-colonized infection, while death was the competing event. A nomogram was established to predict 30-day and 60-day risk of CRE-colonized infection.

RESULTS

879 eligible patients were enrolled in our study and divided into training (n = 761) and validation (n = 118) group, respectively. There were 196 (25.8%) patients suffered from subsequent CRE infection. The median duration of subsequent infection after identification of CRE colonization was 20 (interquartile range [IQR], 14-32) days. Multisite colonization, polymicrobial colonization, catheterization and receiving albumin after colonization, concomitant respiratory diseases, receiving carbapenems and antimicrobial combination therapy before CRE colonization within 90 days were included in final model. Model discrimination and calibration were acceptable for predicting the probability of 60-day CRE-colonized infection in both training (area under the curve [AUC], 74.7) and validation dataset (AUC, 81.1). Decision-curve analysis revealed a significantly better net benefit in current model. Our prediction model is freely available online at https://ken-zheng.shinyapps.io/PredictingModelofCREcolonizedInfection/ .

CONCLUSIONS

Our nomogram has a good predictive performance and could contribute to early identification of CRE carriers with a high-risk of subsequent infection, although external validation would be required.

Culture dependent analysis of bacterial activity, biofilm-formation and oxidative stress of seawater with the contamination of microplastics under climate change consideration

Temperature changes due to climate change and microplastic contamination are worldwide concerns, creating various problems in the marine environment. Therefore, this study was carried out to discover the impact of different temperatures of seawater exposed to different types of plastic materials on culture dependent bacterial responses and oxidative characteristics. Seawater was exposed to microplastics obtained from various plastic materials at different temperature (-18, +4, +20, and +35 °C) for seven days. Then microplastics were removed from the suspension and microplastic-exposed seawater samples were analyzed for bacterial activity, biofilm formation and oxidative characteristics (antioxidant, catalase, glutathione, and superoxide dismutase) using Gram-negative Pseudomonas aeruginosa and Gram-positive Staphylococcus aureus. The results showed that the activity and biofilm formation of Pseudomonas aeruginosa and Staphylococcus aureus were affected through oxidative stress by catalase, glutathione, and superoxide dismutase due to the microplastic deformation by temperature changes. This study confirms that temperature changes as a result of climate change might influence microplastic degradation and their contamination impact in seawater in terms of bacterial metabolic and oxidation reactions.

The sequential microbial breakdown of pectin is the principal incident during water retting of jute (Corchorus spp.) bast fibres

The extraction of bast fibres such as jute from plant stems involves the removal of pectin, hemicellulose, and other noncellulosic materials through a complex microbial community. A consortium of pectinolytic bacterial strains has been developed and commercialized to reduce the retting time and enhance fibre quality. However, there are currently no studies on jute that describe the structural changes and sequential microbial colonization and pectin loss that occur during microbe-assisted water retting. This study investigated the stages of microbial colonization, microbial interactions, and sequential degradation of pectic substances from jute bark under controlled and conventional water retting. The primary occurrence during water retting of bast fibres is the bacterially induced sequential breakdown of pectin surrounding the fibre bundles. The study also revealed that the pectin content of the jute stem significantly decreases during the retting process. These findings provide a strong foundation for improving microbial strains for improved pectinolysis with immense industrial significance, leading to a sustainable jute-based "green" economy.

Derivation and validation of a predictive mortality model of in-hospital patients with Acinetobacter baumannii nosocomial infection or colonization

PURPOSE

Acinetobacter baumannii (Ab) is a Gram-negative opportunistic bacterium responsible for nosocomial infections or colonizations. It is considered one of the most alarming pathogens due to its multi-drug resistance and due to its mortality rate, ranging from 34 to 44,5% of hospitalized patients. The aim of the work is to create a predictive mortality model for hospitalized patient with Ab infection or colonization.

METHODS

A cohort of 140 sequentially hospitalized patients were randomized into a training cohort (TC) (100 patients) and a validation cohort (VC) (40 patients). Statistical bivariate analysis was performed to identify variables discriminating surviving patients from deceased ones in the TC, considering both admission time (T0) and infection detection time (T1) parameters. A custom logistic regression model was created and compared with models obtained from the "status" variable alone (Ab colonization/infection), SAPS II, and APACHE II scores. ROC curves were built to identify the best cut-off for each model.

RESULTS

Ab infection status, use of penicillin within 90 days prior to ward admission, acidosis, Glasgow Coma Scale, blood pressure, hemoglobin and use of NIV entered the logistic regression model. Our model was confirmed to have a better sensitivity (63%), specificity (85%) and accuracy (80%) than the other models.

CONCLUSION

Our predictive mortality model demonstrated to be a reliable and feasible model to predict mortality in Ab infected/colonized hospitalized patients.

Analysis of clinical characteristics of infections caused by shewanella species

PURPOSE

The Shewanella genus is a rare pathogen of marine origin. In recent years, there has been a continuous increase in infection cases caused by this bacterium, and we have observed the uniqueness of infections caused by this microorganism.

MATERIALS AND METHODS

This study conducted a retrospective analysis of the medical history and laboratory examination data of patients infected with the Shewanella genus over the past decade. Additionally, it employed bioinformatics methods to analyze the relevant virulence factors and antibiotic resistance genes associated with the Shewanella genus.

RESULTS

Over the past 10 years, we have isolated 51 cases of Shewanella, with 68.82% being Shewanella putrefaciens (35/51 cases) and 31.37% being Shewanella algae (16/51 cases). Infected individuals often had underlying diseases, with 39.22% (20/51) having malignant tumors and 25.49% (13/51) having liver and biliary system diseases primarily characterized by stones. The majority of patients, 62.74% (32/51), exhibited mixed infections, including one case with a combination of infections from three other types of bacteria and five cases with a combination of infections from two other types of bacteria. The identified microorganisms were commonly resistant to ticarcillin-clavulanic acid (23.5%), followed by cefoperazone-sulbactam (19.6%), ciprofloxacin (17.6%), and cefotaxime (17.6%). Bioinformatics analysis indicates that Shewanella can express bile hydrolysis regulators and fatty acid metabolism regulators that aid in adapting to the unique environment of the biliary tract. Additionally, it expresses abundant catalase, superoxide dismutase, and two-component signal transduction system proteins, which may be related to environmental adaptation. Shewanella also expresses various antibiotic resistance genes, including beta-lactamases and aminoglycoside modification enzymes. Iron carriers may be one of its important virulence factors.

CONCLUSIONS

We speculate that the Shewanella genus may exist as a specific colonizer in the human body, and under certain conditions, it may act as a pathogen, leading to biliary infections in the host.

The EC-COMPASS: Long-term, multi-centre surveillance of Enterobacter cloacae complex - a clinical perspective

BACKGROUND

Enterobacter cloacae complex (ECCO) comprises closely related Enterobacterales, causing a variety of infections ranging from mild urinary tract infections to severe bloodstream infections. ECCO has emerged as a significant cause of healthcare-associated infections, particularly in neonatal and adult intensive care.

AIM

The Enterobacter Cloacae COMplex PASsive Surveillance (EC-COMPASS) aims to provide a detailed multi-centre overview of ECCO epidemiology and resistance patterns detected in routine microbiological diagnostics in four German tertiary-care hospitals.

METHODS

In a sentinel cluster of four German tertiary-care hospitals, all culture-positive ECCO results between 1st January 2020 and 31st December 2022, were analysed based on Hybase® laboratory data.

FINDINGS

Analysis of 31,193 ECCO datasets from 14,311 patients revealed a higher incidence in male patients (P<0.05), although no significant differences were observed in ECCO infection phenotypes. The most common sources of ECCO were swabs (42.7%), urine (17.5%), respiratory secretions (16.1%), blood cultures (8.9%) and tissue samples (5.6%). The annual bacteraemia rate remained steady at approximately 33 cases per hospital. Invasive ECCO infections were predominantly found in oncology and intensive care units. Incidences of nosocomial outbreaks were infrequent and limited in scope. Notably, resistance to carbapenems was consistently low.

CONCLUSION

EC-COMPASS offers a profound clinical perspective on ECCO infections in German tertiary-healthcare settings, highlighting elderly men in oncology and intensive care units as especially vulnerable to ECCO infections. Early detection strategies targeting at-risk patients could improve ECCO infection management.

Epidemiology and molecular characterization of carbapenem-resistant Klebsiella pneumoniae isolated from neonatal intensive care units in General Hospital of Ningxia Medical University, China, 2017-2021

OBJECTIVES

This study aimed to retrospectively investigate the epidemiology and molecular characteristics of carbapenem-resistant Klebsiella pneumoniae (CRKP) isolates from neonatal intensive care units (NICU) between 2017 and 2021.

METHODS

The antibacterial susceptibility of all strains was assessed using the VITEK 2 compact system. The presence of antibiotic resistance, virulence genes, sequence types (STs), capsular (K) types, and the wzi genes was determined through polymerase chain reaction (PCR). Molecular typing was performed by pulsed-field gel electrophoresis (PFGE) using the restriction enzyme XbaI. Additionally, the virulence potential of peg344-positive strains was evaluated using the string test and mouse intraperitoneal infection models. Whole-genome sequencing was conducted on the DNB system and PacBio platforms.

RESULTS

A total of 46 CRKP isolates were collected during the study period. Out of these, 93.47% (43/46) were identified as CRKP strains belonging to the ST76-K10 type carrying blaNDM-5. It was observed that CRKP infection resulted in more severe clinical symptoms compared to CRKP colonization. Among the CRKP strains, a hypervirulent CRKP strain called KP-63, belonging to the ST23 type, was identified. This strain exhibited high mortality in the mouse infection model and was found to possess virulence genes. Genomic alignment analysis revealed a significant similarity between the virulence plasmid from KP-63 strain (pKP-63) and pK2044 from the hypervirulent K. pneumoniae strain NTUH-2044.

CONCLUSIONS

There has been a potential dissemination of ST76-K10 type CRKP carrying blaNDM-5 in the NICU at Ningxia Hospital. Neonatal CRKP infection has been found to cause more severe clinical symptoms than colonization. Furthermore, we have discovered a CR-hvKP strain of ST23 with serotype K1, which exhibits a significant resemblance in its virulent plasmid to pK2044. Therefore, it is crucial to enforce effective measures to restrict the spread and hinder the evolution of CRKP within the hospital.

Epidemiology of carbapenem-resistant Acinetobacter baumannii colonization in neonatal intensive care units: A systematic review and meta-analysis

BACKGROUND

The rising prevalence of carbapenem-resistant Acinetobacter baumannii (CRAB) in neonatal intensive care units (NICUs) represents an escalating challenge in healthcare settings, particularly in managing hospital-acquired infections (HAIs). Studies across various World Health Organization regions have documented a significant incidence of CRAB-related HAIs, with rates as high as 41.7 cases per 1000 patients in ICUs, accounting for 13.6% of all HAIs. These infections pose a doubled mortality risk compared to infections with carbapenem-susceptible Acinetobacter baumannii. A particularly concerning aspect of CRAB colonization is its asymptomatic nature, enabling its transmission through healthcare workers (HCWs) or the NICU environment to vulnerable neonates with developing immune systems.

AIM

To explore the prevalence of CRAB colonization in NICUs, focusing on neonates, healthcare workers, and the environmental samples, to enhance epidemiological understanding and inform targeted interventions.

METHODS

We conducted according to PRISMA 2020 checklist guidelines, a comprehensive literature search across multiple databases including MEDLINE (Ovid), EMBASE (Ovid), Global Health (Ovid), Web of Science, and Global Index Medicus. Studies were selected based on predetermined criteria, primarily involving neonates, HCWs, and environmental swabs, using culture or molecular methods to detect CRAB colonization. We excluded studies that did not specifically focus on NICUs, were duplicates, or lacked necessary data. The study selection and quality assessment were conducted independently by two reviewers. Data extraction involved collecting comprehensive details about each study. Our statistical analysis used a random-effects model to calculate the pooled prevalence and confidence intervals, stratifying results by regional location. We assessed study heterogeneity using Cochran's Q statistic and I² statistic, with regression tests employed to evaluate potential publication bias.

RESULTS

We analyzed 737 records from five databases, ultimately including 13 studies from ten countries. For neonates, the pooled prevalence was 4.8% (95%CI: 1.1% to 10.5%) with the highest rates observed in South-East Asia (10.5%; 95%CI: 2.4% to 23.3%). Among HCWs, a single Indian study reported a 3.3% prevalence. Environmental samples showed a prevalence of 2.3% (95%CI: 0% to 9.3%), with the highest rates in South-East Asia (10%; 95%CI: 4.2% to 17.7%). Significant heterogeneity was found across studies, and no publication bias was detected.

CONCLUSION

This systematic review highlights a significant prevalence of CRAB colonization in neonates across various regions, particularly in South-East Asia, contrasting with lower rates in high-income countries. The study reveals a gap in research on HCWs colonization, with only a single study from India reporting moderate prevalence. Environmental samples indicate moderate levels of CRAB contamination, again higher in South-East Asia. These findings underscore the need for more extensive and focused research on CRAB colonization in NICUs, including exploring the roles of HCWs and the environment in transmission, understanding antimicrobial resistance patterns, and developing effective prevention measures.

Adding vortexing to the Maki technique provides no benefit for the diagnosis of catheter colonization or catheter-related bacteremia

BACKGROUND

A previous study compared vortexing and Maki techniques for the diagnosis of catheter-related bloodstream infection (CRBSI), and concluded that vortexing was not superior to Maki method.

AIM

To determine whether the combined use of vortexing and Maki techniques provides profitability versus the Maki technique for the diagnosis of catheter tip colonization (CTC) and CRBSI.

METHODS

Observational and prospective study carried out in an Intensive Care Unit. Patients with suspected catheter-related infection (CRI) and with one central venous catheter for at least 7 days were included. The area under the curve (AUC) of the Maki technique, the vortexing technique and the combination of both techniques for the diagnosis of CTC and CRBSI were compared.

RESULTS

We included 136 episodes of suspected CRI. We found 21 cases of CTC of which 10 were also CRBSI cases. Of the 21 CTC episodes, 18 (85.7%) were diagnosed by Maki technique and vortexing technique, 3 (14.3%) only by the technique of Maki, and none only by technique of vortexing. Of the 10 CRBSI episodes, 9 (90.0%) were diagnosed by the techniques of Maki and vortexing, 1 (10.0%) was diagnosed only by the technique of Maki, and none only by the technique of vortexing. We no found differences in the comparison of AUC between the technique of Maki and the combination of Maki and vortexing techniques for the diagnosis of CTC (P = 0.99) and CRBSI (P = 0.99).

CONCLUSION

The novel finding of our study was that the combined use of vortexing and Maki techniques did not provide profitability to the technique of Maki alone to CRBSI diagnosis of.

The cAMP receptor protein gene contributes to growth, stress resistance, and colonization of Actinobacillus pleuropneumoniae

Porcine infectious pleuropneumonia (PCP) is a severe disease of porcine caused by Actinobacillus pleuropneumoniae (APP). The spread of PCP remains a threat to the porcine farms and has been known to cause severe economic losses. The cAMP receptor protein (CRP) serves as a pivotal player in helping bacteria adapt to shifts in their environment, particularly when facing the challenges posed by bacterial infections. In this study, we investigated the role of CRP in APP. Our results revealed that crp mutant (Δcrp) strains were more sensitive to acidic and osmotic stress resistance and had lower biofilm formation ability than wild-type (WT) strains. Furthermore, the Δcrp strains showed deficiencies in anti-phagocytosis, adhesion, and invasion upon interaction with host cells. Mice infected with the Δcrp strains demonstrated reduced bacterial loads in their lungs compared to those infected with the WT strains. This study reveals the pivotal role of crp gene expression in regulating pleuropneumonia growth, stress resistance, iron utilization, biofilm formation, phagocytosis, adhesion, invasion and colonization. Our discoveries offer novel perspectives on understanding the development and progression of APP infections.

Nitrogen removal intensification of biofilm through bioaugmentation with Methylobacterium gregans DC-1 during wastewater treatment

The increasing concern for environmental remediation has led to a search for effective methods to remove eutrophic nutrients. In this study, Methylobacterium gregans DC-1 was utilized to improve nitrogen removal in a sequencing batch biofilm reactor (SBBR) via aerobic denitrification. This bacterium has the extraordinary characteristics of strong auto-aggregation and a high ability to remove nitrogen efficiently, making it an ideal candidate for enhanced treatment of nitrogen-rich wastewater. This strain was used for the bioassessment of a test reactor (SBBRbio), which showed a shorter biofilm formation time compared to a control reactor (SBBRcon) without this strain inoculation. Moreover, the enhanced biofilm was enriched in TB-EPS and had a wider variety of protein secondary structures than SBBRcon. During the stabilization phase of SBBRbio, the EPS molecules showed the highest proportion of intermolecular hydrogen bonding. It is possible that bioaugmentation with this strain positively affects the structural stability of biofilm. At influent ammonia loadings of 100 and 150 mg. L-1, the average reduction of ammonia and nitrate-nitrogen was higher in the experimental system compared to the control system. Additionally, nitrite-N accumulation was lower and N2O production decreased compared to the control. Analysis of the microbial community structure demonstrated successful colonization in the bioreactor by a highly nitrogen-tolerant strain that efficiently removed inorganic nitrogen. These results illustrate the great potential of this type of denitrifying bacteria in the application of bioaugmentation systems.

Clinical performance of BALF droplet digital PCR for differential diagnosis of Pneumocystis jirovecii pneumonia and Pneumocystis jirovecii colonization

BACKGROUND

Accurate differentiation between Pneumocystis jirovecii (Pj) infection and colonization is crucial for effective treatment.

METHODS

From September 2016 to June 2022, 89 immunocompromised patients with unexplained lung infiltrates and clinical suspicion of Pj pneumonia were enrolled at Peking University People's Hospital. Bronchoalveolar lavage fluid (BALF) of these patients were detected by quantitative PCR (qPCR) and droplet digital PCR (ddPCR).

RESULTS

The performance of ddPCR was superior to qPCR in detecting Pj infection. Area under the curve was 0.97 (95 %CI: 0.94-1) for ddPCR of the BALF in all patients. The optimal threshold value for discriminating Pj infection from colonization by ddPCR was 13.98 copies/test, with a sensitivity of 97.96 %, specificity of 85.71 %. No obvious correlation between ddPCR copy number and disease severity was observed.

CONCLUSION

BALF ddPCR exhibits robust potential in detecting Pj and effectively discriminating colonization and infection.

Endogenous origin of Pseudomonas aeruginosa infecting hospitalized patients in Ecuador

Recent evidence suggests that Pseudomonas aeruginosa, a bacterium that has the ability to cause deadly infections in hospitalized patients, could originate in the patient's own flora. We employed the Oxford Nanopore platform to obtain whole genome sequences (WGS) from clinical and rectal screen P. aeruginosa strains belonging to 15 patients from two hospitals. Our study found evidence that clinical and rectal isolates were clonal, with some evidence suggesting that the infecting strain was present in the patient's intestine at the time of admission, ruling out hospital acquisition. The use of WGS analysis is crucial to detect alternative sources of P. aeruginosa to develop new preventive measures against these serious infections.

Incidence and risk factors for subsequent infections among rectal carriers with carbapenem-resistant Klebsiella pneumoniae: a systematic review and meta-analysis

BACKGROUND

Carbapenem-resistant Klebsiella pneumoniae (CRKp) is a major pathogen causing nosocomial infections with a high mortality and poor prognosis. Gastrointestinal carriage has been acknowledged as the primary reservoir of CRKp infections.

AIM

To explore the incidence and risk factors associated with CRKp infection following colonization.

METHODS

The PubMed, Web of Science, and Cochrane Library databases were searched for relevant articles published between December 1998 and June 2023. Pooled estimates with a 95% confidence interval (CI) were calculated for the incidence rate, whereas pooled odds ratios (ORs) were calculated for the risk factors for which the OR was reported in three or more studies.

FINDINGS

Fourteen studies were included in the review with 5483 patients for the assessment of incidence, whereas seven of these studies with 2170 patients were included for the analysis of risk factors. In the meta-analysis, the incidence of CRKp infections after colonization was 23.2% (17.9-28.5). Additionally, three independent risk factors for subsequent CRKp infections were identified as admission to the intensive care unit (ICU) (2.59; 95% CI: 1.64-4.11), invasive procedures (2.53; 95% CI: 1.59-4.03), and multi-site colonization (6.24; 95% CI: 2.38-16.33).

CONCLUSION

This review reveals the incidence of CRKp infections in rectal carriers in different countries, emphasizing the role of rectal colonization with CRKp as an important source of nosocomial infections. Significantly, the risk factors indicated in this review can assist clinicians in identifying CRKp carriers with an elevated risk of subsequent infections, thereby enabling further measures to be taken to prevent nosocomial infections.

Faecal microbiota transplantation for multidrug-resistant organism decolonization in spinal cord injury patients: a case series

Introduction

The increase of multidrug-resistant (MDR) bacteria in healthcare settings is a worldwide concern. Isolation precautions must be implemented to control the significant risk of transmitting these pathogens among patients. Antibiotic decolonization is not recommended because of the threat of increasing antibiotic resistance. However, restoring gut microflora through faecal microbiota transplantation (FMT) is a hopeful solution.

Patients and method

In 2019-2022, FMT was indicated in seven patients of the Spinal Cord Unit at University Hospital Motol who were colonized with MDR bacterial strains. Five patients tested positive for carriage of carbapenemase-producing Enterobacteriaceae, and two were carriers of vancomycin-resistant enterococci. Isolation measures were implemented in all patients. Donor faeces were obtained from healthy, young, screened volunteers. According to local protocol, 200-300 ml of suspension was applied through a nasoduodenal tube.

Results

The mean age of the patients was 43 years. The mean length of previous hospital stay was 93.2 days. All patients were treated with broad-spectrum antibiotics for infectious complications before detecting colonisation with MDR bacteria. MDR organism decolonization was achieved in five patients, and consequently, isolation measures could be removed. Colonization persisted in two patients, one of whom remained colonized even after a third FMT. No adverse events were reported after FMT.

Conclusion

FMT is a safe and effective strategy to eradicate MDR bacteria, even in spinal cord injured patients. FMT can allow relaxation of isolation facilitates, the participation of patients in a complete rehabilitation program, their social integration, and transfer to follow-up rehabilitation centres.

The volatile organic compound acetoin enhances the colonization of Azorhizobium caulinodans ORS571 on Sesbania rostrata

Chemoreceptors play a crucial role in assisting bacterial sensing and response to environmental stimuli. Genome analysis of Azorhizobium caulinodans ORS571 revealed the presence of 43 putative chemoreceptors, but their biological functions remain largely unknown. In this study, we identified the chemoreceptor AmaP (methyl-accepting protein of A. caulinodans), characterized by the presence of the CHASE3 domain and exhibited a notable response to acetoin. Thus, we investigated the effect of acetoin sensing on its symbiotic association with the host. Our findings uncovered a compelling role for acetoin as a key player in enhancing various facets of A. caulinodans ORS571's performance including biofilm formation, colonization, and nodulation abilities. Notably, acetoin bolstered A. caulinodans ORS571's efficacy in promoting the growth of S. rostrata, even under moderate salt stress conditions. This study not only broadens our understanding of the AmaP protein with its distinctive CHASE3 domain but also highlights the promising potential of acetoin in fortifying the symbiotic relationship between A. caulinodans and Sesbania rostrata.

Modifiable Preoperative Risk Factors to Mitigate Postoperative Site Infection Following Pediatric Gastrostomy

PURPOSE

There are limited studies assessing modifiable preoperative risk factors for pediatric laparoscopic gastrostomy tubes (LGT) and percutaneous endoscopic gastrostomy (PEG) tubes. We sought to evaluate the effect of demographics and surgical/infectious history on the superficial infection rate following gastrostomy tube (GT) placement.

METHODS

After IRB approval, we conducted a single-institution retrospective cohort study from 2015 to 2021 of pediatric patients undergoing LGT or PEG tube. The primary outcome was cellulitis or abscess formation within 30-days and 90-days postoperatively. Statistical analyses were performed with t-tests, Chi-squared, and logistic regression(p ≤ 0.05).

RESULTS

There were 382 patients, with 181 (47%) LGT and 201 (53%) PEGs. LGT patients were younger (5.9 vs. 12.3 months, p < 0.001) and more likely to be admitted to the neonatal or cardiac intensive care unit prior to their GT. There were similar rates of prior surgical intervention (58% vs. 66%, p = 0.29) and previous infection (37% vs. 38%, p = 0.87) in both LGT and PEG patients. Within 30-days postoperatively, LGT patients had a higher superficial infection rate (12% vs. 6%, p = 0.04). On multivariate regression, Black race (Odds Ratio 0.10, p = 0.03) was protective and prior Staphylococcus colonization (OR 2.35, p = 0.04) increased the odds of infection. In those patients colonized with Staphylococcus, 21% developed a superficial site infection compared to 9% in those not colonized (p = 0.01).

CONCLUSION

These data suggest prior Staphylococcus colonization is a significant risk factor for superficial infection following GT. Further work into preoperative decolonization strategies may provide an avenue to decrease the high infection rate in this common pediatric procedure.

LEVEL OF EVIDENCE

Level III.

Global Indigenous gender concepts, gender-based violence and resilience: A scoping review

BACKGROUND & OBJECTIVE

The legacy of colonialism includes ongoing trauma and disruption of traditional teachings on relationality, which has contributed to Indigenous populations being disproportionately exposed to gender-based violence (GBV). GBV in Indigenous populations is explored to consider gender-specific findings and points of resilience in relational networks.

PARTICIPANTS & SETTING

Included articles sampled Indigenous groups in Canada, US, Mexico, Guatemala, and Israel. All participants self-identified as Indigenous, and were either GBV survivors or service providers working in GBV contexts.

METHODS

A scoping review was conducted in OVID Medline, Embase, APA Psycinfo, and Informit Indigenous Collection, using keywords for Indigenous peoples, gender concepts, and GBV. Articles were screened and extracted by two reviewers; a third reviewer resolved conflicts.

RESULTS

Our search yielded one mixed-method study and seven qualitative studies, all published since 2016. North American studies identified colonial, patriarchal disruptions (e.g. residential schools) to positive pre-contact gender norms (e.g. non-hierarchical roles) that contribute to emerging GBV. Studies conducted in Guatemala and Israel also described local patriarchal cultures contributing to GBV. Lack of understanding of the Two-Spirit identity (i.e. supra-binary gender identity used by Indigenous persons) led to harmful attitudes and stigma. Interpersonal support and return to traditional matriarchal practices were identified as key resilience processes.

CONCLUSIONS

There is limited literature on Indigenous gender concepts and GBV, particularly regarding GBV against males and Two-Spirit persons. Colonization-related violence and/or patriarchal gender norms were identified as precursors for GBV. Decolonization processes should be further explored to address GBV in Indigenous populations.

Can daily bathing with 4% chlorhexidine + daily chlorhexidine wipe for 1 week be effective in decolonizing Candida auris colonization?

BACKGROUND

Herein, it is aimed to present the decolonizing rates of Candida auris colonized cases after daily bathing with 4% chlorhexidine plus daily cleaning with 4% chlorhexidine wipe for 1 week (will be mentioned as DCHX).

METHODS

The study period was from October, 2021, to November, 2022. Inclusion criteria were (i) age > 18, (ii) receiving DCHX, (iii) proven C. auris carrier on auricular, or axillar or inguinal swab surveillance cultures up to 5-day period before DCHX. Cases with three consecutive negative surveillance cultures 3 days apart were considered to be decolonized.

RESULTS

A total of 38 cases [14 female, aged 61.8 ± 15.5 years] fulfilled the inclusion criteria. Six (15.8%), 23 (60.1%), and 22 cases (57.8%) were postauricular, inguinal, and axillary culture positive, respectively. Only three cases (7.9%) were triple culture positive. Nine cases (23.7%) had three consequent negative surveillance cultures after DCHX and were considered to be decolonized. There was no significant difference in decolonization rates of concomitant only antibiotic receiving cohort vs. concomitant antifungal + antibiotic receiving cohort (5/16 vs. 2/8, p = 1) were decolonized similarly. Of the nine C. auris decolonized cases, two developed C. auris infection in 30 days follow-up after decolonization. However, 10 (34.5%) of 29 non-decolonized cases developed C. auris infection (p: 0.450) within 30 days after surveillance culture positivity. Over all cohorts, day 30 mortality was 23.7% (9/38).

CONCLUSION

In conclusion, based on our observational and relatively small uncontrolled series, it appears that DCHX is not very effective in decolonizing C. auris carriers (especially in cases who are C. auris colonized in > 1 areas), although it is not completely ineffective.

Perinatal colonization with extended-spectrum beta-lactamase-producing and carbapenem-resistant Gram-negative bacteria: a hospital-based cohort study

BACKGROUND

Antimicrobial resistance (AMR) is a growing global health threat that contributes to substantial neonatal mortality. Bangladesh has reported some of the highest rates of AMR among bacteria causing neonatal sepsis. As AMR colonization among newborns can predispose to infection with these bacteria, we aimed to characterize the frequency of and risk factors for colonization of mothers and newborns during hospitalization for delivery.

METHODS

We enrolled pregnant women presenting for delivery to a tertiary care hospital in Faridpur, Bangladesh. We collected vaginal and rectal swabs from mothers pre- and post-delivery, rectal swabs from newborns, and swabs from the hospital environment. Swabs were plated on agars selective for extended-spectrum-beta-lactamase producing bacteria (ESBL-PB) and carbapenem-resistant bacteria (CRB). We performed logistic regression to determine factors associated with ESBL-PB/CRB colonization.

RESULTS

We enrolled 177 women and their newborns during February-October 2020. Prior to delivery, 77% of mothers were colonized with ESBL-PB and 15% with CRB. 79% of women underwent cesarean deliveries (C-section). 98% of women received antibiotics. Following delivery, 98% of mothers and 89% of newborns were colonized with ESBL-PB and 89% of mothers and 72% of newborns with CRB. Of 290 environmental samples, 77% were positive for ESBL-PB and 69% for CRB. Maternal pre-delivery colonization was associated with hospitalization during pregnancy (RR for ESBL-PB 1.24, 95% CI 1.10-1.40; CRB 2.46, 95% CI 1.39-4.37). Maternal post-delivery and newborn colonization were associated with C-section (RR for maternal CRB 1.31, 95% CI 1.08-1.59; newborn ESBL-PB 1.34, 95% CI 1.09-1.64; newborn CRB 1.73, 95% CI 1.20-2.47).

CONCLUSIONS

In this study, we observed high rates of colonization with ESBL-PB/CRB among mothers and newborns, with pre-delivery colonization linked to prior healthcare exposure. Our results demonstrate this trend may be driven by intense use of antibiotics, frequent C-sections, and a contaminated hospital environment. These findings highlight that greater attention should be given to the use of perinatal antibiotics, improved surgical stewardship for C-sections, and infection prevention practices in healthcare settings to reduce the high prevalence of colonization with AMR organisms.

Infection prevention-how can we prevent transmission of community-onset methicillin-resistant Staphylococcus aureus?

BACKGROUND

Staphylococcus aureus is a versatile organism, capable of existing as a commensal organism while also possessing pathogenic potential. The emergence of clinically and genetically distinct strains of methicillin-resistant S. aureus (MRSA), termed community-onset MRSA (CO-MRSA), resulted in an epidemic of invasive and skin and soft tissue infections (SSTI) in otherwise healthy individuals without traditional risk factors. Colonization with S. aureus is a risk factor for developing infection and also a source of transmission to close contacts. Outbreaks of S. aureus SSTI have been described in crowded settings and within households. Thus, preventive strategies are essential to interrupt recurrent infections.

OBJECTIVES

The objective of this narrative review is to provide a comprehensive, evidence-based approach to prevent transmission of CO-MRSA. We highlight key clinical trials that emphasize the importance of household and environmental S. aureus colonization in propagating household transmission. Finally, we highlight research priorities to prevent S. aureus infection.

SOURCES

We cite primary literature from peer-reviewed publications as sources for this review.

CONTENT

Our recommended approach to the management of individuals presenting with skin abscesses includes optimal treatment of the initial infection and hygiene education. Decolonization measures should be recommended for individuals with recurrent SSTIs or whose household members have SSTIs. Targeted decolonization with topical antimicrobials should be prescribed to all affected individuals within the household.

IMPLICATIONS

S. aureus infections result in substantial mortality and morbidity because of the high incidence of recurrent skin infections. Although current decolonization strategies are beneficial, interventions are often costly to families and effectiveness wanes over time. Results from a recently completed trial evaluating integrated periodic decolonization and household environmental hygiene will further add to our understanding of what constitutes a sustainable decolonization approach. In addition, novel preventive strategies are being developed such as S. aureus vaccines, lytic agents, probiotics, microbiota transplants, and phage therapy.

Eradication of community-onset Methicillin-resistant Staphylococcus aureus carriage: a narrative review

BACKGROUND

Methicillin-resistant Staphylococcus aureus (MRSA) colonization increases infection risk in both patients and healthy individuals. Decolonization therapy has been proven to reduce S. aureus infections, but data on the effectiveness of individual decolonization strategies in community-onset MRSA carriage are scarce.

OBJECTIVES

The aim of this narrative review was to summarize the evidence on strategies for the elimination of MRSA colonization in community-onset MRSA carriers.

SOURCES

PubMed database was searched for studies on MRSA eradication, from inception to July 2023.

CONTENT

Topical therapy is proven to be effective in nasal-only carriage and in temporary load reduction. Mupirocin nasal ointment in combination with chlorhexidine body wash is highly effective in nasal-only MRSA carriers in the community as well. In patients with extra-nasal colonization, addition of orally administered antibiotics likely increases success rates compared with topical therapy alone. Studies on systemic treatment of extra-nasal MRSA decolonization are subject to a high heterogeneity of antimicrobial agents, treatment duration, and control groups. The majority of evidence supports the use of a combination of topical therapy with rifampin and another antimicrobial agent. Decolonization treatment with probiotics is a promising novel non-antibiotic strategy. However, achieving long-term decolonization is more likely in countries with low MRSA prevalence, given the risk of recolonization in a context of high MRSA prevalence.

IMPLICATIONS

The decision to pursue community-onset MRSA eradication treatment in the individual patient should be based on the combination of the treatment objective (short-term bacterial load reduction in health care settings vs. long-term eradication in community settings), and the likelihood of successful decolonization. The latter is influenced by both individual risk factors for treatment failure, and the risk of recolonization. The addition of a combination of systemic antibiotics is rational for extra-nasal long-term decolonization. To determine the most effective systemic antimicrobial agents in MRSA decolonization, more research is needed.

Disease suppression, growth promotion and colonization attributes of resident endophytic bacteria against white root rot (Dematophora necatrix Hartig) of apple

The inherent potential of apple plants was investigated to explore bacterial endophytes and their role in suppressing Dematophora necatrix, the causative pathogen of white root rot disease. Resultantly 34 endophytic bacteria isolated from healthy apple plants, and subsequently 6 most efficient isolates viz., Bacillus megaterium strain EA3, Enterobacter sp. strain EA7, Bacillus megaterium strain EK2, Stenotrophomonas maltophilia strain EK6, Acinetobacter nosocomialis strain ES2 and Pseudomonas aeruginosa strain ES8 depicting anti-pathogen interactions through preliminary screening were assessed further under in vitro, glasshouse and field conditions against white root rot pathogen/disease. Maximum mycelial growth inhibition (80.37%) was obtained with S. maltophilia strain EK6 encouraging for its seed treatment and soil application thereby providing significant effective control (87.91%) of white root rot under glasshouse conditions to other five bacterial endophytes evaluated simultaneously, followed by field efficacy of 83.70%. In addition, it has significantly enhanced the growth parameters of apple trees under both glasshouse and field conditions. The inoculated healthy plants were assessed for endophytic colonization which revealed maximum endosphere colonialism by S. maltophilia strain EK6. Additionally, confocal microscopic images of transverse sections of root cells colonized by bacterial endophytes as compared to untreated control implied their persistence and establishment in endosphere of apple seedlings. The study provides the first report on interaction between apple associated bacterial root endophytes and D. necatrix. The obtained endophytic strains could be employed as alternative for mitigating white root rot disease in future.

Surveillance on meticillin-sensitive Staphylococcus aureus colonization and infection in a neonatal intensive care unit

BACKGROUND

Meticillin-sensitive Staphylococcus aureus (MSSA) infection is a significant health concern in neonatal intensive care units (NICUs). Bacterial colonization increases the risk of subsequent infection, leading to morbidity and mortality.

AIM

To report the findings of a retrospective cohort study on the surveillance of MSSA colonization and infection in NICU patients.

METHODS

The weekly microbial surveillance results for MSSA colonization in the throat, nose, anus, and groin, as well as invasive and non-invasive MSSA infections, were analysed from November 2020 to June 2022. The MSSA infection and colonization risk were compared after adjustment for confounders by stepwise logistic regression analysis.

FINDINGS

Three hundred and eighty-three neonates were screened; 42.8% (N=164) were MSSA colonized. Significant risk factors for MSSA colonization were length of stay, vaginal delivery and extreme low gestational age <28 weeks (ELGAN) (all P<0.05). The surveillance detected 38 (9.9%) mild MSSA infections and 11 (2.9%) invasive MSSA infections. Neonatal colonization with MSSA is a major risk factor for MSSA infection overall (29.3% in colonized/infected vs 70.7% colonized/not-infected and 0.5% in not-colonized/infected vs 99.5% in not-colonized/not-infected infants) and invasive MSSA infections (6.1% in colonized/infected vs 93.9% in colonized/not-infected and 0.5% in non-colonized/infected vs 99.5% not-colonized/not-infected infants). Also, extreme low birth weight (<1000 g), ELGAN and invasive ventilation were significant risk factors for MSSA infections (all, P<0.05).

CONCLUSIONS

The link between postnatal MSSA colonization and subsequent MSSA infection offers possibilities for prevention. Additional research is needed to explore the association between vaginal birth and the pathogenesis of neonatal MSSA colonization.

Native human and mouse skin infection models to study Candida auris-host interactions

The World Health Organization (WHO) declared certain fungal pathogens as global health threats for the next decade. Candida auris (C. auris) is a newly emerging skin-tropic multidrug-resistant fungal pathogen that can cause life-threatening infections of high mortality in hospitals and healthcare settings. Here, we address an unmet need and present novel native ex vivo skin models, thus extending previous C. auris-host interaction studies. We exploit histology and immunofluorescence analysis of ex vivo skin biopsies of human adult and fetal, as well as mouse origin infected with C. auris via distinct routes. We demonstrate that an intact skin barrier efficiently protects from C. auris penetration and invasion. Although C. auris readily grows on native human skin, it can reach deeper layers only upon physical disruption of the barrier by needling or through otherwise damaged skin. By contrast, a barrier disruption is not necessary for C. auris penetration of native mouse skin. Importantly, we show that C. auris undergoes morphogenetic changes upon skin penetration, as it acquires pseudohyphal growth phenotypes in deeper human and mouse dermis. Taken together, this new human and mouse skin model toolset yields new insights into C. auris colonization, adhesion, growth and invasion properties of native versus damaged human skin. The results form a crucial basis for future studies on skin immune defense to colonizing pathogens, and offer new options for testing the action and efficacy of topical antimicrobial compound formulations.

Synergistic effect of silicon and arbuscular mycorrhizal fungi reduces cadmium accumulation by regulating hormonal transduction and lignin accumulation in maize

Cadmium (Cd) stress causes serious damage to plants, inducing various physiological and biochemical disruptions that lead to reduced plant biomass and compromised growth. The study investigated the combined effects of silicon (Si) and arbuscular mycorrhizal fungi (AMF) on mitigating Cd stress in plants, revealing promising results in enhancing plant tolerance to Cd toxicity. Under Cd stress, plant biomass was significantly reduced (-33% and -30% shoot and root dry weights) as compared to control. However, Si and AMF application ameliorated this effect, leading to increased shoot and root dry weights (+47% and +39%). Furthermore, Si and AMF demonstrated their potential in reducing the relative Cd content (-43% and -36% in shoot and root) in plants and positively influencing plant colonization (+648%), providing eco-friendly and sustainable strategies to combat Cd toxicity in contaminated soils. Additionally, the combined treatment in the Cd-stressed conditions resulted in notable increases in saccharide compounds and hormone levels in both leaf and root tissues, further enhancing the plant's resilience to Cd-induced stress. Si and AMF also played a vital role in positively regulating key lignin biosynthesis genes and altering lignin-related metabolites, shedding light on their potential to fortify plants against Cd stress. These findings underscore the significance of Si and AMF as promising tools in addressing Cd toxicity and enhancing plant performance in Cd-contaminated environments.

Organotypic 3D Ex Vivo Co-culture Model of the Macro-metastasis/Organ Parenchyma Interface

The macro-metastasis/organ parenchyma interface (MMPI) is gaining increasing significance due to its prognostic relevance for cancer (brain) metastasis. We have developed an organotypic 3D ex vivo co-culture model that mimics the MMPI and allows us to evaluate the histopathological growth pattern (HGP) and infiltration grade of the tumor cells into the neighboring brain tissue and to study the interactions of cancer and glial cells ex vivo. This system consists of a murine brain slice and a 3D tumor plug that can be co-cultured for several days. After slicing the brain of 5- to 8-day-old mice, a Matrigel plug containing fluorescent-labelled tumor cells is placed next to it, so that tumor cells in the 3D plug and glial cells in the brain slice can interact at the interface for up to 96 h. To facilitate the positioning of the co-culture and increase the reproducibility of the model, a brain spacer can be used. The HGP and infiltration of the tumor cells into the brain slice as well as the activation of the glial cells can be assessed by live and/or confocal microscopy after immunofluorescence staining of microglia and/or astrocytes. Alternatively, the co-culture can also be used for other purposes, such as RNA analysis. This organotypic 3D ex vivo co-culture offers a perfect tool for preliminary screenings before in vivo experiments and reduces the number of animals, thus contributing to the 3R concept as a central precept in preclinical research.

Polyhydroxyalkanoate production by the plant beneficial rhizobacterium Pseudomonas chlororaphis PCL1606 influences survival and rhizospheric performance

Pseudomonas chlororaphis PCL1606 (PcPCL1606) is a model rhizobacterium used to study beneficial bacterial interactions with the plant rhizosphere. Many of its beneficial phenotypes depend on the production of the antifungal compound 2-hexyl, 5-propyl resorcinol (HPR). Transcriptomic analysis of PcPCL1606 and the deletional mutant in HPR production ΔdarB strain, assigned an additional regulatory role to HPR, and allowed the detection of differentially expressed genes during the bacterial interaction with the avocado rhizosphere. Interestingly, the putative genes phaG (PCL1606_46820) and phaI (PCL1606_56560), with a predicted role in polyhydroxyalkanoate biosynthesis, were detected to be under HPR control. Both putative genes were expressed in the HPR-producing wild-type strain, but strongly repressed in the derivative mutant ΔdarB, impaired in HPR production. Thus, a derivative mutant impaired in the phaG gene was constructed, characterized and compared with the wild-type strain PcPCL1606 and with the derivative mutant ΔdarB. The phaG mutant had strongly reduced PHA production by PcPCL1606, and displayed altered phenotypes involved in bacterial survival on the plant roots, such as tolerance to high temperature and hydrogen peroxide, and decreased root survival, in a similar way that the ΔdarB mutant. On the other hand, the phaG mutant does not have altered resistance to desiccation, motility, biofilm formation or adhesion phenotypes, as displayed by the HPR-defective ΔdarB mutant have. Interestingly, the mutant defective in PHA production also lacked a biocontrol phenotype against the soilborne pathogenic fungus Rosellinia necatrix, even when the derivative mutant still produced the antifungal HPR compound, demonstrating that the final biocontrol phenotype of PcPCL1606 first requires bacterial survival and adaptation traits to the soil and rhizosphere environment.

Factors affecting vancomycin-resistant Enterococcus faecium colonization of in-hospital patients in different wards

Objectives

The prevalence of vancomycin-resistant Enterococcus faecium (VRE) infection at a medical center in Eastern Taiwan rose to 80.6%, exceeding the average prevalence of 55.6% among all medical centers nationwide during the same period. In recent years, the number of cases of VRE infection detected among hospitalized patients has increased annually. However, most of these patients in different wards are asymptomatic carriers. Therefore, restricting active screening to high-risk units will not improve the current situation, and it is necessary to review the risk factors for VRE colonization to provide a reference for future infection control policies.

Materials and Methods

Between 2014 and 2019, there were 3188 VRE-positive cultures reported at our institution, as per the electronic medical records system.

Results

In the medical and surgical wards, patients who received penicillin (odds ratios [ORs]: 2.84 and 4.16, respectively) and third-generation cephalosporins (ORs: 3.17 and 6.19, respectively) were at higher risk of VRE colonization. In intensive care units, the use of carbapenems (OR: 2.08) was the most significant variable.

Conclusion

This study demonstrated that the risk factors for VRE colonization differed between wards. Thus, policies should be established according to the attributes of patients in each ward, and active screening tests should be performed according to individual risks, instead of a policy for comprehensive mass screening.

Carboxymethyl konjac glucomannan-chitosan complex nanogels stabilized emulsions incorporated into alginate as microcapsule matrix for intestinal-targeted delivery of probiotics: In vivo and in vitro studies

In this study, we developed a novel delivery system using carboxymethyl konjac glucomannan-chitosan (CMKGM-CS) nanogels stabilized single and double emulsion incorporated into alginate hydrogel as microcapsule matrix for intestinal-targeted delivery of probiotics. Through in vitro experiments, it was demonstrated that alginate hydrogel provided favorable biocompatible growth conditions for the proliferation of Lactobacillus reuteri (LR). The alginate hydrogel containing single (ASE) or double emulsions (ACG) enhanced the resistance of LR to various adverse environments. Simulated gastrointestinal digestion experiments revealed that the survivability of LR in free, CON, ASE and ACG group decreased by 6.45 log CFU/g, 4.21 log CFU/g, 1.26 log CFU/g and 0.65 log CFU/g, respectively. In vivo studies conducted in mice showed that ACG maintained its integrity during passage through the stomach and released the probiotics in the targeted intestinal area, whereas the pure alginate hydrogels (CON) were prematurely released in the gastrointestinal tract. Moreover, the viable counts of ACG in different intestinal segments (jejunum, ileum, cecum, and colon) were increased by 1.11, 1.42, 1.68, and 1.89 log CFU/g, respectively, after 72 h of oral administration compared to the CON group. This research contributed valuable insights into the development of an effective microbial delivery system with potential applications in the biopharmaceutical and food industries.

[Multiple PCR ALLPLEX TM ENTERO-DR for multidrug-resistant Enterobacteriaceae management at Albacete University Hospital]

OBJECTIVE

Multi-resistant Enterobacteriaceae (MRE) are a public health threat, with screening and isolation strategies being important to stop its dissemination. Multiplex PCR is a novel method capable of rapid diagnosis with high sensitivity and specificity. In this study, our objective was to evaluate its application to multidrug-resistant Enterobacteriaceae management since its implementation in our hospital.

METHODS

An observational retrospective descriptive study of multiplex PCR ALLPLEX TM ENTERO-DR results to screen inpatients colonized by MRE took place from November 2019 to May 2021. We calculated the percentage of positive, negative, non-identifiable or invalid results, identified microorganisms, reason for requesting it and subsequent actions. Median and I.R. from sampling time to partial and theoretical culture time, and since last colonization/infection depending on test results were calculated.

RESULTS

Resistance mechanisms were detected in 31.47% of tests, being E. coli ESBL (68.99%) the most frequently isolated microorganism. Median time to partial result was 5.75 hours (I.R.: 2.67), having statistically significant differences with theoretical time. The most important reason to request the test was screening (80.12%) and the most frequent action taken was not to isolate (41.70 %). Whenever forty-nine months or more since last colonization/infection have passed, only 14.81% of the samples tested positive.

CONCLUSIONS

Multiplex PCR is a useful test to manage colonized patients, capable of giving a rapid result and allowing for quicker decision-making, contributing to a good use of resources and patient comfort.

Candida spp. in Human Intestinal Health and Disease: More than a Gut Feeling

Fungi are an essential part of the normal collection of intestinal microorganisms, even though their collective abundance comprises only 0.1-1% of all fecal microbes. The composition and role of the fungal population is often studied in relation to early-life microbial colonization and development of the (mucosal) immune system. The genus Candida is frequently described as one of the most abundant genera, and altered fungal compositions (including elevated abundance of Candida spp.) have been linked with intestinal diseases such as inflammatory bowel disease and irritable bowel syndrome. These studies are performed using both culture-dependent and genomic (metabarcoding) techniques. In this review, we aimed to summarize existing data on intestinal Candida spp. colonization in relation to intestinal disease and provide a brief overview of the biological and technical challenges in this field, including the recently described role of sub-species strain variation of intestinal Candida albicans. Together, the evidence for a contributing role of Candida spp. in pediatric and adult intestinal disease is quickly expanding, even though technical and biological challenges may limit full understanding of host-microbe interactions.

Multidrug-resistant Gram-negative bacterial colonization in patients, carriage by healthcare workers and contamination of hospital environments in Ghana

BACKGROUND

Patients already colonized with multidrug-resistant (MDR) Gram-negative bacteria (GNB) on admission to critical care units may be an important source of transmission of these bacteria in hospitals. We sought to determine the prevalence of MDR GNB colonization in patients, staff and the ward environment and to assess the risk factors for colonization of patients in wards.

METHODS

The study was conducted from April 2021 to July 2021 in a teaching hospital in Ghana. MDR GNB were isolated from rectal, and hand swabs were taken from patients on admission and after 48 h. Swabs from HCW's hands and the ward environment were also taken. Risk factors for colonization with MDR GNB were assessed using univariate and multivariate analysis.

RESULTS

MDR GNB rectal colonization rate among patients was 50.62% on admission and 44.44% after 48 h. MDR GNB were isolated from 6 (5.26%) and 24 (11.54%) of HCW's hand swabs and environmental swabs, respectively. Previous hospitalization (p-value = 0.021, OR, 95% CI= 7.170 (1.345-38.214) was significantly associated with colonization by MDR GNB after 48 h of admission. Age (21-30 years) (p-value = 0.022, OR, 95% CI = 0.103 (0.015-0.716) was significantly identified as a protective factor associated with a reduced risk of rectal MDR GNB colonization.

CONCLUSION

The high colonization of MDR GNB in patients, the carriage of MDR GNB on HCW's hands, and the contamination of hospital environments highlights the need for patient screening and stringent infection prevention and control practices to prevent the spread of MDR GNB in hospitals.

Negligible role for pneumococcal surface protein A (PspA) and pneumococcal surface protein C (PspC) in the nasopharyngeal colonization of mice with a serotype 6B pneumococcal strain

Streptococcus pneumoniae colonizes the human nasopharynx asymptomatically, but it can also cause several diseases, including otitis media, pneumonia, bacteremia, and meningitis. The colonization of the nasopharynx by the bacteria is an essential step for the pneumococcus to invade other sites and cause diseases. Pneumococcal surface protein A (PspA) and Pneumococcal surface Protein C (PspC) are important virulence factors and have been described to play roles in adhesion and immune evasion. In this study, we immunized mice subcutaneously with the recombinant α-helical region of PspA and/or PspC combined with different adjuvants to assess protection against colonization with the serotype 6B strain BHN418. Though high serum levels of specific IgG were detected, none of the formulations led to reduction in the colonization of the nasopharynx. The negative result may be due to the poor induction of IgG2c, which has been previously correlated with protection against pneumococcal colonization in mice. Furthermore, BHN418 pspA and pspC single and double knockouts were evaluated in colonization experiments and no differences in bacterial load were observed. In competition assays with the wild-type strain, borderline to no reduction was observed in the loads of the knockouts. Our results contrast with data from the literature using other pneumococcal strains, showing that the role of PspA and PspC in colonization can vary depending on the background of the knockout strain studied. BHN418 has been selected for its capacity to colonize humans in experimental challenge studies and may have redundant factors that compensate for the lack of PspA and PspC during nasopharyngeal colonization of mice.

Impact of intestinal colonization by Gram-negative bacteria on the incidence of bloodstream infections and lethality in critically ill neonates

BACKGROUND

Early detection of antimicrobial-resistant microorganisms is crucial to prevent subsequent invasive infections and contain their spread in the Neonatal Intensive Care Unit (NICU). This study aims to investigate the association between intestinal colonization (IC) by Gram-negative bacteria and the risk of bloodstream infection (BSI) in critically ill neonates.

METHODS

Data from the electronic medical records of 678 newborns admitted to a NICU Brazilian between 2018 and 2022 were retrospectively analyzed. Participants were monitored by the National Health Security Network.

RESULTS

Among neonates, 6.9 % had IC (56.9 % attributed to Acinetobacter baumannii); of these, 19.1 % developed BSI (66.7 % by Staphylococcus spp.). Within the A. baumannii colonization, 34.5 % occurred during an outbreak in September 2021. Colonized individuals had a longer mean length of stay (49.3 ± 26.4 days) and higher mortality rate (12.8 %) compared to non-colonized individuals (22.2 ± 16.9 days; 6.7 %, respectively). Previous use of antimicrobials and invasive devices significantly increased the risk of colonization. Colonization by drug-resistant microorganisms, along with the occurrence of BSI, was associated with increased mortality and reduced survival time.

CONCLUSIONS

IC contributed to the incidence of BSI, leading to more extended hospital stays and higher mortality rates. Its early detection proved to be essential to identify an outbreak and control the spread of resistant microorganisms within the NICU.

Microbiology and management of respiratory infections in children with tracheostomy

Tracheostomy-related respiratory infections are common, though the diagnosis and management can be challenging in children. The goal of this review article was to provide an overview of the current knowledge known about recognizing and treating respiratory infections in this population and to emphasize future areas for further research. While several small and retrospective papers attempt to provide information, there remain more questions than answers. We have reviewed ten published articles to understand this topic, bringing to light significant variation in clinical practices across institutions. While identifying the microbiology is important, it is also crucial to recognize when to treat. Differentiating acute infection, chronic infection, and colonization are important features that influence the treatment of lower respiratory tract infection in children with a tracheostomy.

Clinical significance and burden of carbapenem-resistant Enterobacterales (CRE) colonization acquisition in hospitalized patients

BACKGROUND

Carbapenem-resistant Enterobacterales (CRE) infections have a significant morbidity and mortality toll. The clinical significance and associated burden of CRE colonization rather than infection state are not frequently investigated. We aimed to assess the outcomes of CRE colonized patients compared to matched controls.

METHODS

A secondary analysis of a 1:2 matched case-control study at a tertiary hospital in northern Israel (January-2014 to June-2017). Cases were adults who newly acquired CRE colonization during hospitalization. Controls were inpatients negatively screened for CRE, matched by age, hospitalization division and total days of hospitalization 90 days prior to screening. Our primary outcome was 1-year all-cause mortality. Secondary outcomes included 30-day mortality, diagnosis of any clinical infection, overall days of hospital stay and bloodstream infections all in 1-year follow-up. We estimated crude and propensity score weighted estimates for study outcomes.

RESULTS

We included a total of 1019 patients: 340 CRE colonized and 679 non-colonized controls. After adjustment, CRE colonization was not associated with increased 1-year mortality (weighted OR 0.98, 95% CI 0.64-1.50, p = 0.936). CRE colonized patients had 1.7 times the odds of clinical infection of any cause (weighted odds ratio (OR) 1.65, 95% CI 1.06-2.56, p = 0.025). CRE colonized patients had increased length of hospital stay compared to controls (weighted OR 1.52, 95%CI 1.10-2.10, p < 0.001) among 1-year survivors.

CONCLUSIONS

CRE colonization may not be independently associated with mortality but with higher risk of clinical infections and longer hospital stays. Infection prevention and antimicrobial stewardship are of utmost importance to prevent acquisition and infections in colonized patients.

ELK3-ID4 axis governs the metastatic features of triple negative breast cancer

Purpose

Cancer cell metastasis is a multistep process, and the mechanism underlying extravasation remains unclear. ELK3 is a transcription factor that plays a crucial role in regulating various cellular processes, including cancer metastasis. Based on the finding that ELK3 promotes the metastasis of triple-negative breast cancer (TNBC), we investigated whether ELK3 regulates the extravasation of TNBC by forming the ELK3-ID4 axis. ID4 functions as a transcriptional regulator that interacts with other transcription factors, inhibiting their activity and subsequently influencing various biological processes associated with cell differentiation, survival, growth, and metastasis.

Methods

We assessed the correlation between the expression of ELK3 and that of ID4 in TNBCs using bioinformatics analyses, QRT-PCR, western blot analysis, luciferase reporter assays, and chromatin immunoprecipitation. Migration, adhesion, invasion, and lung metastasis assays were employed to determine whether the ELK3-ID4 axis regulates the metastatic features of TNBC.

Results

We found that ELK3 binds directly to a binding motif close to the ID4 promoter to repress promoter activity. The expression of E-cadherin in TNBC was regulated by the ELK3-ID4 axis. In vitro and in vivo analyses showed that inhibiting ID4 expression in ELK3-knockdown MDA-MB-231 (ELK3KD) cells restored the ability to extravasate and metastasize.

Conclusion

The results indicate that the ELK3 regulates ID4 promoter activity, and that the ELK3-ID4 axis regulates the metastatic characteristics of TNBC cells. Additionally, the data suggest that the ELK3-ID4 axis regulates metastasis of TNBCs by modulating expression of E-cadherin.

Anti-diarrheal drug loperamide induces dysbiosis in zebrafish microbiota via bacterial inhibition

BACKGROUND

Perturbations of animal-associated microbiomes from chemical stress can affect host physiology and health. While dysbiosis induced by antibiotic treatments and disease is well known, chemical, nonantibiotic drugs have recently been shown to induce changes in microbiome composition, warranting further exploration. Loperamide is an opioid-receptor agonist widely prescribed for treating acute diarrhea in humans. Loperamide is also used as a tool to study the impact of bowel dysfunction in animal models by inducing constipation, but its effect on host-associated microbiota is poorly characterized.

RESULTS

We used conventional and gnotobiotic larval zebrafish models to show that in addition to host-specific effects, loperamide also has anti-bacterial activities that directly induce changes in microbiota diversity. This dysbiosis is due to changes in bacterial colonization, since gnotobiotic zebrafish mono-colonized with bacterial strains sensitive to loperamide are colonized up to 100-fold lower when treated with loperamide. Consistently, the bacterial diversity of gnotobiotic zebrafish colonized by a mix of 5 representative bacterial strains is affected by loperamide treatment.

CONCLUSION

Our results demonstrate that loperamide, in addition to host effects, also induces dysbiosis in a vertebrate model, highlighting that established treatments can have underlooked secondary effects on microbiota structure and function. This study further provides insights for future studies exploring how common medications directly induce changes in host-associated microbiota. Video Abstract.

The updates on metastatic mechanism and treatment of colorectal cancer

Colorectal cancer (CRC) is a main cause of cancer death worldwide. Metastasis is a major cause of cancer-related death in CRC. The treatment of metastatic CRC has progressed minimally. However, the potential molecular mechanisms involved in CRC metastasis have remained to be comprehensively clarified. An improved understanding of the CRC mechanistic determinants is needed to better prevent and treat metastatic cancer. In this review, based on evidence from a growing body of research in metastatic cancers, we discuss the cellular and molecular mechanisms involved in CRC metastasis. This review reveals both the molecular mechanisms of metastases and identifies new opportunities for developing more effective strategies to target metastatic relapse and improve CRC patient outcomes.

Impacts of colonization on Indigenous food systems in Canada and the United States: a scoping review

BACKGROUND

Indigenous populations in Canada and the United States (US) have maintained reciprocal relationships with nature, grounded in respect for and stewardship of the environment; however, disconnection from traditional food systems has generated a plethora of physical and mental health challenges for communities. Indigenous food sovereignty including control of lands were found to be factors contributing to these concerns. Therefore, our aim was to conduct a scoping review of the peer-reviewed literature to describe Indigenous disconnection from Indigenous food systems (IFS) in Canada and the US.

METHODS

Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses for Scoping Reviews (PRISMA-SR) and Joanna Briggs Institute guidelines, we searched MEDLINE, SCOPUS, International Bibliography of the Social Sciences, Sociological Abstracts, and Bibliography of Native North Americans. Data was extracted from 41 studies and a narrative review completed based on study themes.

RESULTS

The overarching theme identified in the included studies was the impact of colonization on IFS. Four sub-themes emerged as causes for Indigenous disconnection from traditional food systems, including: climate change; capitalism; legal change; and socio-cultural change. These sub-themes highlight the multiple ways in which colonization has impacted Indigenous food systems in Canada and the US and important areas for transformation.

CONCLUSIONS

Efforts to reconnect Indigenous knowledge and values systems with future food systems are essential for planetary health and sustainable development. Traditional knowledge sharing must foreground authentic Indigenous inclusion within policymaking.

Maize Seedlings Colonization with Serendipita indica and Its Colonization Efficiency Analysis

Maize is one of the most important crops in the world, and ensuring its successful growth and productivity is crucial for global food security. One way to enhance maize growth and productivity is by improving the colonization of its roots by beneficial microorganisms. In this regard, Serendipita indica, a plant growth-promoting fungus, has gained attention for its ability to enhance plant growth and productivity, especially in cereal crops and medicinal plants. Previous studies have shown that S. indica can colonize various plant species, including maize, but the efficiency of the colonization process in maize seedlings has not been extensively characterized. This protocol outlines a method for efficient colonization of maize seedlings with the beneficial fungus S. indica. The protocol includes the preparation of stock solutions, maintenance and growth of S. indica, surface sterilization and germination of seeds, preparation of S. indica chlamydospores, and colonization of maize plants with S. indica. The advantages of this protocol include the use of surface sterilization techniques that minimize contamination, the production of a large number of viable chlamydospores, and efficient colonization of maize seedlings with S. indica. This protocol may be useful for researchers studying the role of S. indica in promoting plant growth and combating biotic and abiotic stress. Additionally, this protocol may be used in the development of biofertilizers using S. indica as a means of increasing crop yields and reducing dependence on synthetic fertilizers. Overall, this protocol offers a reliable and efficient method for colonizing maize seedlings with S. indica and may have potential applications in the agricultural industry. This study also provides a valuable tool for researchers interested in studying plant-microbe interactions in maize and highlights the potential of S. indica as a biocontrol agent to enhance maize productivity under adverse conditions. Key features • This protocol builds upon the method developed by Narayan et al. (2022), and its application optimized for the root endophytic symbiotic fungus S. indica. • This protocol also allows for histochemical analysis to visualize the colonized fungal spores in the root cells of host plant species. • This protocol helps in mathematical calculation of the percent colonization or efficiency of colonization. • This protocol utilizes readily available laboratory equipment, including a light microscope, autoclave, and laminar flow hood, ensuring ease of reproducibility in other research laboratories.

Novel methodologies for host-microbe interactions and microbiome-targeted therapeutics in 3D organotypic skin models

BACKGROUND

Following descriptive studies on skin microbiota in health and disease, mechanistic studies on the interplay between skin and microbes are on the rise, for which experimental models are in great demand. Here, we present a novel methodology for microbial colonization of organotypic skin and analysis thereof.

RESULTS

An inoculation device ensured a standardized application area on the stratum corneum and a homogenous distribution of bacteria, while preventing infection of the basolateral culture medium even during prolonged culture periods for up to 2 weeks at a specific culture temperature and humidity. Hereby, host-microbe interactions and antibiotic interventions could be studied, revealing diverse host responses to various skin-related bacteria and pathogens.

CONCLUSIONS

Our methodology is easily transferable to a wide variety of organotypic skin or mucosal models and different microbes at every cell culture facility at low costs. We envision that this study will kick-start skin microbiome studies using human organotypic skin cultures, providing a powerful alternative to experimental animal models in pre-clinical research. Video Abstract.

The effects of microbial fertilizers application on growth, yield and some biochemical changes in the leaves and seeds of guar (Cyamopsis tetragonoloba L.)

Guar (Cyamopsis tetragonoloba L.) is a summer legume that is becoming a crucial industrial crop because of its high gum and protein content. Thus far, the combined effects of arbuscular mycorrhizal fungi (AMF) and Bradyrhizobium on the yield and chemical composition of guar plants are not well studied. Therefore, the current investigation was designed to estimate the individual as well as the combined effects of AMF and Bradyrhizobium on plant growth, yield and nutritional quality of seeds and leaves of guar. AMF and/or Bradyrhizobium inoculation improved chemical composition of guar seeds and its morpho-physiological (plant height, fresh weight, dry weight, and yield production) traits. In addition to increased guar growth and yield production, the inoculation of AMF and/or Bradyrhizobium increased guar leaf and seed minerals, fiber, lipids, crude protein and ash contents. At primary metabolites, there were increases in sugar levels including raffinose stachyose, verbascose and galactomannan. These increases in sugar provided a route for organic acids, amino acids and fatty acids production. Interestingly, there was an increase in essential amino acids and unsaturated fatty acids. At the bioactive secondary metabolite levels, biofertilizers improved phenols and flavonoids levels and anthocyanin and polyamines biosynthesis. In line with these increases, precursors of anthocyanin (phenylalanine, p-coumaric acid, and cinnamic acid) and the levels of polyamines (diaminopropane, putrescine, cadaverine, spermidine, spermine, and agmatine) were increased. Overall, for the first time, our study shed the light on how AMF and Bradyrhizobium improved guar yield and metabolism. Our findings suggested that the combined inoculation of AMF and Bradyrhizobium is an innovative approach to improve guar growth, yield production and yield quality.

Phylogeography of the true freshwater crab, Geothelphusa dehaani: Detected dual dispersal routes via land and sea

Dispersal is an important factor that determines the potential for colonization to pioneer sites. Although most decapods employ seaward migration for reproduction with a planktonic larval phase, true freshwater crabs spend their entire life cycle in freshwater. Therefore, it is expected that genetic regionality can be easily detected. In this study, we focused on true freshwater crabs, Geothelphusa Stimpson, 1858. Herein, we reveal the evolutionary history and dispersal patterns of freshwater crustaceans. We collected and genetically analyzed 283 specimens at 138 localities across the Japanese Islands. Phylogenetic analyses were conducted on the combined dataset (mtDNA COI, 16S, and nDNA ITS1, histone H3 regions) and the data set based on the mtDNA COI region. The phylogenetic relationships detected 10 clades that were highly monophyletic. The highlights of this study were the discovery of several cryptic species or undescribed species, and the completely different heterogeneous dual dispersal pathways within a single species; i.e., both land and ocean routes. Although it was concluded that Japanese crabs are basically genetically divided by straits, strong evidence for dispersion via ocean currents was also detected (i.e., a "sweepstake"). It was also confirmed that Geothelphusa dehaani (White, 1847) could survive in seawater.

Rearranging and completing the puzzle: Phylogenomic analysis of bark beetles Dendroctonus reveals new hypotheses about genus diversification

Studies carried out on bark beetles within Dendroctonus have been extensive and revealed diverse information in different areas of their natural history, taxonomy, evolution, and interactions, among others. Despite these efforts, phylogenetic hypotheses have remained obscured mainly due to limited information analyzed (taxonomic, gene sampling, or both) in studies focused on obtaining evolutionary hypotheses for this genus. With the aim of filling these gaps in the evolutionary history for Dendroctonus, we analyzed ∼1800 loci mapped to a reference genome obtained for 20 of the 21 species recognized to date, minimizing the impact of missing information and improving the assumption of orthology in a phylogenomic framework. We obtained congruent phylogenetic topologies from two phylogenomic inference strategies: loci concatenation (ML framework) and a multispecies coalescent model (MSC) through the analysis of site pattern frequencies (SNPs). Dendroctonus is composed of two major clades (A and B), each containing five and four subclades, respectively. According to our divergence dating analysis, the MRCA for Dendroctonus dates back to the early Eocene, while the MRCA for each major clade diverged in the mid-Eocene. Interestingly, most of the speciation events of extant species occurred during the Miocene, which could be correlated with the diversification of pine trees (Pinus). The MRCA for Dendroctonus inhabited large regions of North America, with all ancestors and descendants of clade A having diversified within this region. The Mexican Transition Zone is important in the diversification processes for the majority of clade A species. For clade B, we identified two important colonization events to the Old World from America: the first in the early Oligocene from the Arctic to Asia (via Beringia), and the second during the Miocene from the Arctic-Western-Alleghany region to Europe and Siberia (also via Beringia). Our genomic analyses also supported the existence of hidden structured lineages within the frontalis complex, and also that D. beckeri represent a lineage independent from D. valens, as previously suggested. The information presented here updates the knowledge concerning the diversification of a genus with remarkable ecological and economic importance.

Pneumococcal colonization and severity of pneumonia in hospitalized Cambodian children following introduction of the 13-valent pneumococcal conjugate vaccine

Objectives

This study sought to characterize pneumococcal colonization and clinical/radiological features in Cambodian children admitted to hospital with an illness compatible with pneumonia following national introduction of the 13-valent pneumococcal conjugate vaccine (PCV13).

Methods

Children aged 0-59 months admitted to Angkor Hospital for Children who met the World Health Organization (WHO) case definition for clinical pneumonia were enrolled over a 3-year period. Clinical, radiological and vaccination data were collected at enrolment. A nasopharyngeal swab was collected for detection of pneumococcal colonization using the WHO standard culture method.

Results

Between 1 September 2015 and 31August 2018, 2209 analysable illness episodes were enrolled. Pneumococci were detected in 943/2209 (42.7%) children. PCV13 serotypes were detected less frequently in children who had been vaccinated appropriately for their age compared with undervaccinated children: 309/567 (53.6%) vs 216/342 (63.2%) (P=0.006). Age-appropriate PCV13 vaccination was negatively associated with hypoxic presentation [adjusted odds ratio (aOR) 0.72, 95% confidence interval (CI) 0.60-0.87; P=0.0006] and primary endpoint pneumonia on chest x ray (aOR 0.69, 95% CI 0.54-0.90; P=0.006).

Conclusions

The introduction of PCV13 in Cambodia was associated with a decline in vaccine serotype nasopharyngeal colonization, and clinical and radiological severity in children hospitalized with clinical pneumonia.