Colonization Factor Research Articles

Sweet complexity: O-linked protein glycosylation in pathogenic Neisseria.

The genus Neisseria, which colonizes mucosal surfaces, includes both commensal and pathogenic species that are exclusive to humans. The two pathogenic Neisseria species are closely related but cause quite different diseases, meningococcal sepsis and meningitis (Neisseria meningitidis) and sexually transmitted gonorrhea (Neisseria gonorrhoeae). Although obvious differences in bacterial niches and mechanisms for transmission exists, pathogenic Neisseria have high levels of conservation at the levels of nucleotide sequences, gene content and synteny. Species of Neisseria express broad-spectrum O-linked protein glycosylation where the glycoproteins are largely transmembrane proteins or lipoproteins localized on the cell surface or in the periplasm. There are diverse functions among the identified glycoproteins, for example type IV biogenesis proteins, proteins involved in antimicrobial resistance, as well as surface proteins that have been suggested as vaccine candidates. The most abundant glycoprotein, PilE, is the major subunit of pili which are an important colonization factor. The glycans attached can vary extensively due to phase variation of protein glycosylation (pgl) genes and polymorphic pgl gene content. The exact roles of glycosylation in Neisseria remains to be determined, but increasing evidence suggests that glycan variability can be a strategy to evade the human immune system. In addition, pathogenic and commensal Neisseria appear to have significant glycosylation differences. Here, the current knowledge and implications of protein glycosylation genes, glycan diversity, glycoproteins and immunogenicity in pathogenic Neisseria are summarized and discussed.

The adjuvant BcfA activates antigen presenting cells through TLR4 and supports TFH and TH1 while attenuating TH2 gene programming.

Adjuvants added to subunit vaccines augment antigen-specific immune responses. One mechanism of adjuvant action is activation of pattern recognition receptors (PRRs) on innate immune cells. Bordetella colonization factor A (BcfA); an outer membrane protein with adjuvant function, activates TH1/TH17-polarized immune responses to protein antigens from Bordetella pertussis and SARS CoV-2. Unlike other adjuvants, BcfA does not elicit a TH2 response. To understand the mechanism of BcfA-driven TH1/TH17 vs. TH2 activation, we screened PRRs to identify pathways activated by BcfA. We then tested the role of this receptor in the BcfA-mediated activation of bone marrow-derived dendritic cells (BMDCs) using mice with germline deletion of TLR4 to quantify upregulation of costimulatory molecule expression and cytokine production in vitro and in vivo. Activity was also tested on human PBMCs. PRR screening showed that BcfA activates antigen presenting cells through murine TLR4. BcfA-treated WT BMDCs upregulated expression of the costimulatory molecules CD40, CD80, and CD86 and produced IL-6, IL-12/23 p40, and TNF-α while TLR4 KO BMDCs were not activated. Furthermore, human PBMCs stimulated with BcfA produced IL-6. BcfA-stimulated murine BMDCs also exhibited increased uptake of the antigen DQ-OVA, supporting a role for BcfA in improving antigen presentation to T cells. BcfA further activated APCs in murine lungs. Using an in vitro TH cell polarization system, we found that BcfA-stimulated BMDC supernatant supported TFH and TH1 while suppressing TH2 gene programming. Overall, these data provide mechanistic understanding of how this novel adjuvant activates immune responses.

Pathogenicity of enterotoxigenic Escherichia coli in Caenorhabditis elegans as an alternative model host.

Enterotoxigenic Escherichia coli (ETEC), one of the diarrheagenic E. coli, is the most common cause of diarrhea in developing country and in travelers to those areas. In this study, Caenorhabditis elegans was used as an alternative model host to evaluate ETEC infections. The ETEC strain ETEC1, which was isolated from a patient with diarrhea, possessed enterotoxins STh, LT1, and EAST1 and colonization factors CS2 and CS3. Live ETEC1 shortened the life span and body size of C. elegans in association with increased expression of enterotoxin genes and intestinal colonization. In contrast, heat-killed ETEC1 did not affect the life span of C. elegans. Caenorhabditis elegans infected with ETEC1 showed upregulated expression of genes related to insulin-like peptides and host defense responses. These results suggest that ETEC1 exhibits pathogenicity through intestinal colonization and enterotoxin production in C. elegans. This system is useful as an ETEC infection model.

Prevalence, antimicrobial resistance, and genetic lineages of nasal Staphylococcus aureus among medical students at a Spanish University: detection of the MSSA-CC398-IEC-type-C subclade

Medical students could be a potential source of Staphylococcus aureus transmission to patients. This cross-sectional study involved samples collected from both nasal nostrils. Samples were processed for S. aureus recovery; the antimicrobial resistance (AMR) phenotype was determined by disc diffusion assays and the spa types and AMR genotypes by PCR/sequencing. A structured questionnaire was administered to students to collate data related to potential risk factors of nasal colonization. Ninety-eight students were included, 50 % were colonized by S. aureus and 12.2 % by MRSA. The mecA gene was detected in all MRSA isolates. The MSSA-CC398-IEC-type C lineage was found among 16.3 % of nasal carriers, of which t571 was the predominant spa-type. MRSA isolates were ascribed to spa types t2226 (CC5, 12 isolates) and t3444 (new spa type, 1 isolate). All MRSA were multi-drug resistant and MSSA were predominantly resistant to erythromycin-clindamycin (inducible-type, mediated by ermT gene). High rates of S. aureus and MRSA nasal carriages were observed in this study. The predominance of the CC398 lineage among MSSA (emergent invasive lineage) represent a relevant finding of public health concern. The role of medical students as potential source of MRSA and MSSA-CC398 transmissions in hospital and community needs to be elucidated in detail.

Genomic and epidemiological insight of an outbreak of carbapenemase-producing Enterobacterales in a Portuguese hospital with the emergence of the new KPC-124

BackgroundCarbapenemase-producing Enterobacterales (CPE) is an increasing problem in healthcare settings. This study aimed to identify the source of a CPE outbreak that occurred in 2022, in a tertiary hospital in the North of Portugal, to identify exposed patients, and to assess the risk of becoming CPE-positive following hospital admission. MethodsA multi-disciplinary investigation was conducted including descriptive, analytical, and molecular epidemiology, environmental screening, and assessment of infection control measures. Clinical and environmental isolates were analyzed using whole-genome sequencing and phylogenetic analysis. Additionally, a prospective observational cohort study was conducted to further investigate the risk factors associated with the emergence of new cases in cohorts of CPE-negative admitted patients. ResultsWe observed the presence of multispecies KPC-, IMP-, and/or NDM-producing isolates. Genetically indistinguishable clinical and environmental isolates were found on the same room/ward. The ST45 KPC-3-producing Klebsiella pneumoniae clone was the responsible for the outbreak. During patients’ treatment, we detected the emergence of resistance to ceftazidime-avibactam, associated with mutations in the blaKPC-3 gene (blaKPC-46, blaKPC-66 and blaKPC-124, the last variant never previously reported), suggesting a vertical evolutionary trajectory. Patients aged ≥ 75 years, hygiene/feeding-care dependent, and/or subjected to secretion aspiration were risk factors for CPE colonization after hospital admission. Additionally, cases with previous admission to the emergency department suggest that CPE dissemination may occur not only during hospitalization but also in the emergency department. ConclusionOverall, the study highlights that selection pressure with antibiotics, like ceftazidime-avibactam, is a contributing factor to the emergence of new β-lactamase variants and antibiotic resistance. It also shows that the hospital environment can be a significant source of CPE transmission, and that routine use of infection control measures and real-time molecular epidemiology investigations are essential to ensure the long-term termination of CPE outbreaks and prevent future resurgences.

HMO-primed bifidobacteria exhibit enhanced ability to adhere to intestinal epithelial cells.

The ability of gut commensals to adhere to the intestinal epithelium can play a key role in influencing the composition of the gut microbiota. Bifidobacteria are associated with a multitude of health benefits and are one of the most widely used probiotics for humans. Enhanced bifidobacterial adhesion may increase host-microbe, microbe-nutrient, and/or microbe-microbe interactions, thereby enabling consolidated health benefits to the host. The objective of this study was to determine the ability of human milk oligosaccharides (HMOs) to enhance bifidobacterial intestinal adhesion in vitro. This study assessed the colonisation-promoting effects of HMOs on four commercial infant-associated Bifidobacterium strains (two B. longum subsp. infantis strains, B. breve and B. bifidum). HT29-MTX cells were used as an in vitro intestinal model for bacterial adhesion. Short-term exposure of four commercial infant-associated Bifidobacterium strains to HMOs derived from breastmilk substantially increased the adherence (up to 47%) of these probiotic strains. Interestingly, when strains were incubated with HMOs as a four-strain combination, the number of viable bacteria adhering to intestinal cells increased by >90%. Proteomic analysis of this multi-strain bifidobacterial mixture revealed that the increased adherence resulting from exposure to HMOs was associated with notable increases in the abundance of sortase-dependent pili and glycosyl hydrolases matched to Bifidobacterium bifidum. This study suggests that HMOs may prime infant gut-associated Bifidobacterium for colonisation to intestinal epithelial cells by influencing the expression of various colonization factors.

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

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

Role of Probiotics in Preventing Carbapenem-Resistant Enterobacteriaceae Colonization in the Intensive Care Unit: Risk Factors and Microbiome Analysis Study.

Older patients with multiple comorbidities often necessitate prolonged hospital stays and antibiotic treatment in the intensive care unit (ICU), leading to a rise in multidrug-resistant organisms like carbapenem-resistant Enterobacteriaceae (CRE). This study examined risk factors for carbapenem-resistant Enterobacteriaceae colonization in the ICU and assessed probiotics' preventive role. In this single-center, retrospective study, 9099 ICU patients were tested for stool CRE culture from March 2017 to April 2022. We excluded 136 patients with CRE colonization within one week post-admission and 26 who received probiotics before CRE colonization. Ultimately, 8937 CRE-negative patients were selected. Logistic analysis identified CRE colonization risk factors and evaluated probiotics' influence, including Saccharomyces boulardii or Lactobacillus rhamnosus, used by 474 patients (5.3%) in the ICU. Compared with data on initial admission, 157 patients (1.7%) had newly discovered CRE colonization before discharge. In a multivariate analysis, coronavirus disease 2019, the ICU, tube feeding, antibiotics such as aminoglycoside, extended-spectrum penicillin, stool vancomycin-resistance enterococci colonization, and chronic kidney disease were significantly associated with de novo CRE infection. However, probiotic use was negatively correlated with CRE infection. Managing risk factors and administering probiotics in the ICU may help prevent CRE colonization; large randomized prospective studies are needed.

Prevalence of and risk factors for intestinal colonisation by multidrug-resistant Gram-negative bacteria in patients with haematological malignancies: A systematic review and meta-analysis

BackgroundPatients with haematological malignancies (HM patients) are at high risk of infections caused by multidrug-resistant Gram-negative bacteria (MDR-GNB). MDR-GNB intestinal colonisation is associated with MDR-GNB infections. The aim of this systematic review and meta-analysis on HM patients was to pool the prevalence of and risk factors for intestinal colonisation by MDR-GNB, including carbapenem-resistant Enterobacterales (CRE) and extended-spectrum β-lactamase (ESBL)-producing Enterobacterales, reported in previous studies. MethodsThis study was conducted according to the protocol registered in PROSPERO (CRD42022374425). PubMed, Embase, Web of Science, Ovid MEDLINE(R) ALL and Cochrane Library were searched from inception to 25 October 2022. Observational studies reporting CRE and/or ESBL intestinal colonisation in HM patients were included. Subgroup analyses were conducted by study region. ResultsA total of 21 402 HM patients from 32 studies were analysed. The pooled CRE and ESBL colonisation rates were 21.7% [95% confidence interval (95%CI) 18.7–24.8] and 19.2% (95%CI 13.9–24.5), respectively. Prior exposure to tigecycline [odds ratio (OR) 3.99, 95%CI 2.08–7.68], carbapenem (OR 1.84, 95%CI 1.13-2.97) or penicillin (OR 1.72, 95%CI 1.05–2.83), as well as chemotherapy (OR 2.45, 95%CI 1.05–5.73), neutropenia (OR 1.88, 95%CI 1.08–3.26) and acute myeloid leukaemia (AML; OR 1.86, 95%CI 1.33–2.61), were risk factors for CRE colonisation in HM patients. Prior antibiotic exposure was a risk factor for ESBL colonisation in HM patients (OR 4.90, 95%CI 2.76–8.70). ConclusionsThis study shows the high prevalence of MDR-GNB (CRE and ESBL) colonisation in HM patients and explains associated factors for the colonisation. The results provide evidence for MDR-GNB infection control in HM management.

Risk factors for the colonization of carbapenem-resistant Enterobacteriaceae in patients transferred to a small/medium-size hospital in Korea: a retrospective study

Purpose: This study aimed to identify the colonization rate of carbapenem-resistant Enterobacteriaceae (CRE), the characteristics of CRE isolates, and risk factors for CRE colonization in patients transferred to the general wards of a small/medium-sized hospital.Methods: This retrospective study was conducted on patients who underwent CRE culture tests within 24 hours of admission among patients transferred to a small/medium-sized hospital. Forty-seven patients confirmed as positive for CRE were classified as belonging to the patient group. For the control group, 235 patients (five times the number of the patient group) were matched by sex, age, and diagnosis, and then selected at random. Data were analyzed using descriptive analysis and multiple logistic regression analysis.Results: The CRE colonization rate was 5% (47 out of 933 patients), and Klebsiella pneumoniae (68.0%) was the most common isolate of CRE. The positivity rate of carbapenemase-producing Enterobacteriaceae was 61.7%. The risk factors for CRE colonization included renal disease (odds ratio [OR]=4.93; 95% confidence interval [CI], 1.49-16.31), heart disease (OR=3.86; 95% CI, 1.35-11.01), indwelling urinary catheters (OR=4.43; 95% CI, 1.59-12.36), and cephalosporin antibiotic use (OR=8.57; 95% CI, 1.23-59.60). Conclusion: Having a comorbid renal or cardiac disease, an indwelling urinary catheter, or a history of exposure to cephalosporin antibiotics could be classified as risk factors for CRE colonization in patients transferred to small and medium-size hospitals. It is necessary to perform active infection control through proactive CRE culture testing of patients with risk factors.

2604. Contact With School-Aged Children is a Major Risk Factor for Pneumococcal Colonization in Older Adults

Abstract Background Important questions remain about the role of older adults in driving transmission of pneumococcus in the community. This is a critical question for understanding the potential indirect effects of using pneumococcal conjugate vaccines (PCVs) in older adults. For non-institutionalized individuals, the most likely source of adult-to-adult transmission is in the household. The goal of this study was to characterize the dynamics and risk factors for acquisition of pneumococcus in older adults. Methods We designed a longitudinal study to sample adults > 60 years of age living in the same household (New Haven, CT), and without younger contacts residing in the household. Saliva samples and questionnaires regarding social behaviors and health status were obtained every 2 weeks for a period of 10 weeks. DNA extracted from culture-enriched saliva was tested using qPCR for pneumococcus genes piaB and lytA. Results Across the two study seasons (November 2020-August 2021, November 2021-September 2022), 184 individuals from 93 households were sampled and completed all 6 visits. Overall, 31/184 (16.8%) individuals were colonized on at least one time point based on qPCR detection of piaB. Two individuals were colonized at 6/6 time points, and two others were colonized at 5/6 time points during the 10-week sampling period. In 7/93 (7.5%) households, both members were colonized, though not necessarily at the same time point. Pneumococcal colonization was substantially higher among individuals who had contact with children < 18 years as compared to those with no recent contact with children (9.4% vs 2.3%). Participants who reported recent contact with < 5 year olds and 5-9 year olds had particularly elevated prevalence (14.3%; 13.0%, respectively). Conclusion Pneumococcal acquisition related to adult-to-adult transmission is low. Contact with pre-school and young school-aged children was the most important factor that influenced acquisition rates of pneumococcus among older adult households. Disclosures Anne L. Wyllie, PhD, Co-Diagnostics: Board Member|Merck: Grant/Research Support|Pfizer: Advisor/Consultant|Pfizer: Grant/Research Support Ronika Alexander-Parrish, RN, MAEd, Pfizer, Inc.: Employee|Pfizer, Inc.: Stocks/Bonds Adriano Arguedas, Medical director, Pfizer: Emplyee|Pfizer: Stocks/Bonds Bradford D. Gessner, M.D., M.P.H., Pfizer: I am an employee of Pfizer|Pfizer: Stocks/Bonds Daniel M. Weinberger, PhD, GSK: Advisor/Consultant|Merck: Advisor/Consultant|Merck: Grant/Research Support|Pfizer: Advisor/Consultant|Pfizer: Grant/Research Support

724. Prevalence and Risk Factors for Carbapenem Resistant Enterobacterales Colonization on Admission to Two Intensive Care Units in India

Abstract Background Carbapenem-resistant Enterobacterales (CRE) infections are endemic in Indian hospitals however, studies examining intestinal colonization of CRE on admission to intensive care units (ICUs) are very limited. This study examines the prevalence and risk factors for CRE colonization on admission to two ICUs in a tertiary-care hospital in India. Methods Peri-rectal swabs were collected from consented patients prospectively enrolled between December 16, 2022 and March 31, 2023 in the medical ICU (MICU) and surgical ICU (SICU). Swabs were plated on selective agar (CHROMagarTMmSuperCARBATM) within 24 hours of collection for CRE isolation. Identification and susceptibility of presumed CRE isolates were confirmed by VITEK2. The modified carbapenem inactivation (mCIM) test and the EDTA carbapenem inactivation method (eCIM) were used to assess carbapenemase production. Information on CRE colonization risk factors (hospitalization and ICU stay in last one year, transfer from outside hospital, long-term hemodialysis) was collected. Results A total of 453 patients were admitted to both ICUs during the study period and 158 patients gave consent. Overall CRE prevalence among 158 patients was 54% (86/158). Peri-rectal swab was obtained within 48 hours of admission for 78 patients (Figure 1), and CRE prevalence in this cohort was 42% [33/78], with significantly higher prevalence noted among patients in the MICU compared to SICU (63% [17/27] vs 31% [16/51], p=0.007). Hospitalization, or ICU admission within the last 1 year, and long-term dialysis were significantly associated with CRE colonization (Table 1). Among 33 patients with CRE colonization on admission, the most common CRE isolated was Klebsiella pneumoniae (59% [20/34 isolates]) followed by Escherichia coli (38% [13/34 isolates]). Among the 34 CRE isolates, 19 were metallo-beta-lactamase producers and 15 were serine carbapenemase producers. Table 1 Conclusion High prevalence of CRE colonization on admission was observed in the two ICUs, with prior hospitalization significantly associated with CRE colonization. Significantly higher proportion of CRE colonization was seen in the MICU as compared to SICU. Future studies should examine the risk factors associated with CRE acquisition during hospitalization to design interventions. Disclosures All Authors: No reported disclosures

The Impact of MRSA Colonization on Healthcare-Associated Infections in Long-Term Care Facility Residents: A Whole-Genome Sequencing-Based Study.

Methicillin-resistant Staphylococcus aureus (MRSA) colonization has been considered a risk factor for the development of infection, however, there are no studies that have compared the colonizing and infecting strains using whole-genome sequencing (WGS). The aim of this study is to determine the prevalence of and risk factors for MRSA colonization among long-term care facilities (LTCF) residents of Tenerife (Spain), and to analyze the epidemiological relationship between the colonizing and infecting strains using WGS. A point-prevalence study was carried out at 14 LTCFs in Tenerife from October 2020 to May 2021. Nasal swabs were cultured for MRSA. Colonized residents were followed up for two years. A phylogenetic comparison between colonization and infection strains was performed using WGS. A total of 764 residents were included. The prevalence of colonization by MRSA was 28.1% (n = 215), of which 12 (5.6%) subsequently developed infection. A close genetic relationship between colonization and infection isolates was found in three of the four (75%) residents studied. Our study confirms that colonized residents can develop serious MRSA infections from the same nasal colonization strain. Given the high prevalence of MRSA colonization in these centers, it is necessary to implement strategies with preventive measures to avoid the development of infection and the transmission of MRSA.

Vancomycin resistant enterococcus risk factors for hospital colonization in hematological patients: a matched case-control study

BackgroundVancomycin-resistant enterococcus (VRE) was the fastest growing pathogen in Europe in 2022 (+ 21%) but its clinical relevance is still unclear. We aim to identify risk factors for acquired VRE rectal colonization in hematological patients and evaluate the clinical impact of VRE colonization on subsequent infection, and 30- and 90-day overall mortality rates, compared to a matched control group.MethodsA retrospective, single center, case–control matched study (ratio 1:1) was conducted in a hematological department from January 2017 to December 2020. Case patients with nosocomial isolation of VRE from rectal swab screening (≥ 48 h) were matched to controls by age, sex, ethnicity, and hematologic disease. Univariate and multivariate logistic regression compared risk factors for colonization.ResultsA total of 83 cases were matched with 83 controls. Risk factors for VRE colonization were febrile neutropenia, bone marrow transplant, central venous catheter, bedsores, reduced mobility, altered bowel habits, cachexia, previous hospitalization and antibiotic treatments before and during hospitalization. VRE bacteraemia and Clostridioides difficile infection (CDI) occurred more frequently among cases without any impact on 30 and 90-days overall mortality. Vancomycin administration and altered bowel habits were the only independent risk factors for VRE colonization at multivariate analysis (OR: 3.53 and 3.1; respectively).ConclusionsAntimicrobial stewardship strategies to reduce inappropriate Gram-positive coverage in hematological patients is urgently required, as independent risk factors for VRE nosocomial colonization identified in this study include any use of vancomycin and altered bowel habits. VRE colonization and infection did not influence 30- and 90-day mortality. There was a strong correlation between CDI and VRE, which deserves further investigation to target new therapeutic approaches.

Evaluation of Mode of Delivery and Various Postnatal Factors on Acquisition of Oral Streptococcus mutans in Infants: A Prospective Study.

The objective of the current study is to assess and establish a relationship between the mode of delivery and postnatal factors in the early colonization of Streptococcus mutans (S. mutans) in infants' oral cavities. The primary goal of the investigation is to assess and compare the oral microflora of newborns immediately after birth and at 3, 6, 9, and 12 months of age in babies born by normal vaginal delivery and lower segment cesarean section and divided into (group III) and (group V), respectively. Around 50 mother-baby pairs in total had their swab samples collected for the identification of S. mutans and were monitored for a year. The role of other postnatal factors in the acquisition of S. mutans in infants was also evaluated. Data analysis showed that different postnatal factors like feeding patterns, oral hygiene practices, and socioeconomic factors affected the infant's oral cavity's initial colonization by S. mutans. Infants' first exposure to oral S. mutans depends on the delivery method and various postnatal factors. Sharma N, Bhargava N, Boruah B, et al. Evaluation of Mode of Delivery and Various Postnatal Factors on Acquisition of Oral Streptococcus mutans in Infants: A Prospective Study. Int J Clin Pediatr Dent 2023;16(5):663-666.

Treatment with a Lactococcus lactis that chromosomally express E. coli cfaI mitigates salivary flow loss in a Sjögren’s syndrome-like disease

Sjögren’s Syndrome (SjS) results in loss of salivary and lacrimal gland excretion due to an autoimmune attack on these secretory glands. Conventional SjS treatments address the symptoms, but not the cause of disease. Recognizing this deficit of treatments to reverse SjS disease, studies were pursued using the fimbriae from enterotoxigenic E. coli, colonization factor antigen I (CFA/I), which has anti-inflammatory properties. To determine if CFA/I fimbriae could attenuate SjS-like disease in C57BL/6.NOD-Aec1Aec2 (SjS) females, the Lactococcus lactis (LL) 301 strain was developed to chromosomally express the cfaI operon. Western blot analysis confirmed CFA/I protein expression, and this was tested in SjS females at different stages of disease. Repeated dosing with LL 301 proved effective in mitigating salivary flow loss and in reducing anti-nuclear antibodies (ANA) and inflammation in the submandibular glands (SMGs) in SjS females and in restoring salivary flow in diseased mice. LL 301 treatment reduced proinflammatory cytokine production with concomitant increases in TGF-β+ CD25+ CD4+ T cells. Moreover, LL 301 treatment reduced draining lymph and SMG follicular T helper (Tfh) cell levels and proinflammatory cytokines, IFN-γ, IL-6, IL-17, and IL-21. Such evidence points to the therapeutic capacity of CFA/I protein to suppress SjS disease and to have restorative properties in combating autoimmune disease.

The adhesin SCF1 mediates Candida auris colonization

Candida auris is an emerging human fungal pathogen that can rapidly spread and cause outbreaks of invasive infections. Santana et al. discovered that a novel surface colonization factor (SCF1), and a conserved adhesin, Iff4109, mediates C. auris colonization on abiotic surfaces, skin, and virulence in vivo.

Modelled-Microgravity Reduces Virulence Factor Production in Staphylococcus aureus through Downregulation of agr-Dependent Quorum Sensing.

Bacterial contamination during space missions is problematic for human health and damages filters and other vital support systems. Staphylococcus aureus is both a human commensal and an opportunistic pathogen that colonizes human tissues and causes acute and chronic infections. Virulence and colonization factors are positively and negatively regulated, respectively, by bacterial cell-to-cell communication (quorum sensing) via the agr (accessory gene regulator) system. When cultured under low-shear modelled microgravity conditions (LSMMG), S. aureus has been reported to maintain a colonization rather than a pathogenic phenotype. Here, we show that the modulation of agr expression via reduced production of autoinducing peptide (AIP) signal molecules was responsible for this behavior. In an LSMMG environment, the S. aureus strains JE2 (methicillin-resistant) and SH1000 (methicillin-sensitive) both exhibited reduced cytotoxicity towards the human leukemia monocytic cell line (THP-1) and increased fibronectin binding. Using S. aureus agrP3::lux reporter gene fusions and mass spectrometry to quantify the AIP concentrations, the activation of agr, which depends on the binding of AIP to the transcriptional regulator AgrC, was delayed in the strains with an intact autoinducible agr system. This was because AIP production was reduced under these growth conditions compared with the ground controls. Under LSMMG, S. aureus agrP3::lux reporter strains that cannot produce endogenous AIPs still responded to exogenous AIPs. Provision of exogenous AIPs to S. aureus USA300 during microgravity culture restored the cytotoxicity of culture supernatants for the THP-1 cells. These data suggest that microgravity does not affect AgrC-AIP interactions but more likely the generation of AIPs.

Comparison of risk factors for Methicillin Resistant Staphylococcus aureus (MRSA) colonization in healthy newborns, born to mothers with and without MRSA colonization.

To compare the risk factors for MRSA colonization in healthy newborns, born of mothers with and without MRSA colonization. This case control study was conducted in post-natal unit of Lady Willingdon Hospital, affiliated with King Edward Medical University/Mayo Hospital, Lahore from January to June 2017. The vaginal and anterior nares swabs for MRSA culture were collected from mothers within six hours before planned delivery and the neonatal anterior nares swabs for MRSA culture were taken within one hour of birth. All the samples were cultured in Paediatric Microbiology laboratory in Mayo Hospital. Data were analyzed through SPSS 20.0 and logistic regression was applied for risk factors analysis. Out of total 80 mothers and their newborns, 15 (18.75%) mothers and 16 neonates (20%) were MRSA colonized. The frequency of MRSA colonization in mothers' anterior nares and vaginal swab was 17.5% and 1.25% respectively. The significant risk factors were prolonged rupture of membranes for >18 hours (p-value 0.02, odds ratio 11.85, 95% CI 1.41-99.3), birth weight <2500 grams (p-value 0.01, odds ratio 5.39, 95% CI 1.35-21.4), history of presence of meconium (p-value 0.006, odds ratio 7.30, 95% CI 1.78-29.8). The non-significant factors were age of mother (p-value 0.682, odds ratio 0.765, 95% CI 1.0.212-2.76), parity (p-value 0.185, odds ratio 3.82, 95% CI 0.46-31.66) , gestation (p-value 0.615, odds ratio 0.797, 95% CI 0.714-0.89) , mode of delivery (p-value 0.576, odds ratio 0.543, 95% CI 0.062-4.76), sex of baby (p-value 0.546, odds ratio 0.683, 95% CI 0.196-2.37) and presentation of baby at birth (p-value 0.47, odds ratio 0.795, 95% CI 0.71-0.89). The presence of meconium, prolonged rupture of membranes and low birth weight were the significant risk factors for MRSA colonization in healthy new-borns, born to mothers with and without MRSA colonization.

A First in Human Clinical Trial Assessing the Safety and Immunogenicity of Two Intradermally Delivered Enterotoxigenic Escherichia coli CFA/I Fimbrial Tip Adhesin Antigens with and without Heat-Labile Enterotoxin with Mutation LT(R192G).

Enterotoxigenic E. coli (ETEC) is a leading cause of diarrhea in travelers as well as for children living in low- to middle-income countries. ETEC adhere to intestinal epithelium via colonization factors (CFs). CFA/I, a common CF, is composed of a polymeric stalk and a tip-localized minor adhesive subunit, CfaE. Vaccine delivery by the transcutaneous immunization of dscCfaE was safe but was poorly immunogenic in a phase 1 trial when administered to volunteers with LTR(192G) and mLT. To potentially enhance the immunogenicity of CfaE while still delivering via a cutaneous route, we evaluated the safety and immunogenicity of two CfaE constructs administered intradermally (ID) with or without mLT. CfaE was evaluated as a donor strand-complemented construct (dscCfaE) and as a chimeric construct (Chimera) in which dscCfaE replaces the A1 domain of the cholera toxin A subunit and assembles non-covalently with the pentamer of heat-labile toxin B (LTB). Subjects received three ID vaccinations three weeks apart with either dscCfaE (1, 5, and 25 µg) or Chimera (2.6 and 12.9 µg) with and without 0.1 µg of mLT. Subjects were monitored for local and systemic adverse events. Immunogenicity was evaluated by serum and antibody-secreting cell (ASC) responses. The vaccine was well-tolerated with predominantly mild and moderate local vaccine site reactions characterized by erythema, induration and post-inflammatory hyperpigmentation. High rates of serologic and ASC responses were seen across study groups with the most robust responses observed in subjects receiving 25 µg of dscCfaE with 0.1 mcg of LT(R192G). Both ETEC adhesin vaccine prototypes were safe and immunogenic when co-administered with mLT by the ID route. The observed immune responses induced with the high dose of dscCfaE and mLT warrant further assessment in a controlled human infection model.