Prevalence of rectal carbapenem resistant Enterobacterales carriage among patients attending healthcare facilities in Ibadan, Nigeria: a descriptive study.

BACKGROUND: Carbapenem Resistant Enterobacterales (CRE) infections are increasingly associated with or directly responsible for morbidity and mortality from bacterial infections in sub-Saharan Africa where there are limited antibiotic options. CRE rectal colonization of patients in healthcare facilities provides a reservoir of these organisms and could potentially cause invasive infections in these settings. The prevalence of rectal carriage among patients attending healthcare facilities in Nigeria has not been previously described. We set out to assess the prevalence of rectal CRE carriage and their antibiotic susceptibility patterns among patients attending healthcare facilities in Nigeria. METHODS: A descriptive cross-sectional study was carried out from December 2021 to September 2022 in Ibadan, in which patients attending primary, secondary and tertiary healthcare facilities were screened for rectal carriage of CRE by microscopy, culture and sensitivity of rectal swab specimens. RESULTS: A total of 291 patients were screened; 45 (15.5%), 66 (22.7%) and 180 (61.8%) at primary, secondary and tertiary healthcare facilities, respectively. All but one of them had received a third-generation cephalosporin or carbapenem in the preceding 30 days. The mean age was 28.8 years and 55.7% were male. Overall, 51 (17.5%) participants had CRE colonization, with 5(11.1%), 9(13.6%) and 37(20.6%) at primary, secondary and tertiary healthcare facilities, respectively (p = 0.243). Regarding antimicrobial susceptibility, 43(84.3%) CRE isolates were resistant to at least 3 different classes of antibiotics while two Escherichia coli isolates were resistant to all 5 classes of antibiotics tested. The lowest rates of CRE resistance were to tigecycline (6, 11.5%) and colistin (8, 15.7%). CONCLUSIONS: In this first study on CRE colonization in Nigeria, we found that a substantial proportion of patients in three levels of healthcare facilities had rectal carriage of CRE, including pan-resistant isolates. Active surveillance and appropriate infection prevention and control practices (IPC) need to be urgently strengthened to mitigate the risk of active CRE infection. TRIAL REGISTRATION: Not applicable.

The TAK1/JNK axis participates in adaptive immunity by promoting lymphocyte activation in Nile tilapia.

The transforming growth factor beta-activated kinase 1 (TAK1)/c-Jun N-terminal kinase (JNK) axis is an essential MAPK upstream mediator and regulates immune signaling pathways. However, whether the TAK1/JNK axis harnesses the strength in regulation of signal transduction in early vertebrate adaptive immunity is unclear. In this study, by modeling on Nile tilapia (Oreochromis niloticus), we investigated the potential regulatory function of TAK1/JNK axis on lymphocyte-mediated adaptive immune response. Both OnTAK1 and OnJNK exhibited highly conserved sequences and structures relative to their counterparts in other vertebrates. Their mRNA was widely expressed in the immune-associated tissues, while phosphorylation levels in splenic lymphocytes were significantly enhanced on the 4th day post-infection by Edwardsiella piscicida. In addition, OnTAK1 and OnJNK were significantly up-regulated in transcriptional level after activation of lymphocytes in vitro by phorbol 12-myristate 13-acetate plus ionomycin (P + I) or PHA, accompanied by a predominant increase in phosphorylation level. More importantly, inhibition of OnTAK1 activity by specific inhibitor NG25 led to a significant decrease in the phosphorylation level of OnJNK. Furthermore, blocking the activity of OnJNK with specific inhibitor SP600125 resulted in a marked reduction in the expression of T-cell activation markers including IFN-γ, CD122, IL-2, and CD44 during PHA-induced T-cell activation. In summary, these findings indicated that the conserved TAK1/JNK axis in Nile tilapia was involved in adaptive immune responses by regulating the activation of lymphocytes. This study enriched the current knowledge of adaptive immunity in teleost and provided a new perspective for understanding the regulatory mechanism of fish immunity.

Preliminary snapshot reveals a relationship between multidrug-resistance and biofilm production among enterobacteriaceae isolated from fecal samples of farm-raised poultry in ceará, Brazil.

Antimicrobial resistance and biofilm formation by microbial pathogens pose a significant challenge to poultry production systems due to the persistent risk of dissemination and compromise of bird health and productivity. In this context, the study aimed to investigate the occurrence of different multiresistance phenotypes and the biofilm-forming ability of Enterobacteriaceae isolated from broiler chicken excreta in poultry production units in Ceará, Brazil. Samples were collected from three distinct broiler breeding facilities and subjected to isolation, identification, antibiotic susceptibility testing, phenotypic screening for ß-lactamases enzymes, and biofilm formation evaluation. Seventy-one strains were identified, being Escherichia coli (37 %) and Proteus mirabilis (32 %), followed by Klebsiella pneumoniae (11 %), Providencia stuartii (9 %), Klebsiella aerogenes (6 %), Alcaligenes faecalis (4 %), and Salmonella sp. (1 %). A significant proportion (87 %) of multiresistant strains were detected. For the phenotypic evaluation of ß-lactamases production, strains with resistance to second and third-generation cephalosporins and carbapenems were tested. About 4 of 6 and 10 of 26 were positive for inducible chromosomal AmpC ß-lactamase and extended-spectrum ß-lactamase (ESBL), respectively. Regarding biofilm formation, it was observed that all MDR strains were capable of forming biofilm. In this sense the potential of these MDR bacteria to develop biofilms becomes a significant concern, representing a real threat to both human and animal health, as biofilms offer stability, antimicrobial protection, and facilitate genetic transfer.

Bacterial diversity and specific taxa are associated with decolonization of carbapenemase-producing enterobacterales after fecal microbiota transplantation.

OBJECTIVES: We evaluated the effect of fecal microbiota transplantation (FMT) on the clearance of carbapenemase-producing Enterobacterales (CPE) carriage. METHODS: We performed a prospective, multi-center study, conducted among patients who received a single dose of FMT from one of four healthy donors. The primary endpoint was complete clearance of CPE carriage two weeks after FMT with a secondary endpoint at three months. Shotgun metagenomic sequencing was performed to assess gut microbiota composition of donors and recipients before and after FMT. RESULTS: Twenty CPE-colonized patients were included in the study, where post-FMT 20% (n = 4/20) of patients met the primary endpoint and 40% (n = 8/20) of patients met the secondary endpoint. Kaplan-Meier curves between patients with FMT intervention and the control group (n = 82) revealed a similar rate of decolonization between groups. Microbiota composition analyses revealed that response to FMT was not donor-dependent. Responders had a significantly lower relative abundance of CPE species pre-FMT than non-responders, and 14 days post-FMT responders had significantly higher bacterial species richness and alpha diversity compared to non-responders (p < 0.05). Responder fecal samples were also enriched in specific species, with significantly higher relative abundances of Faecalibacterium prausnitzii, Parabacteroides distasonis, Collinsella aerofaciens, Alistipes finegoldii and Blautia_A sp900066335 (q<0.01) compared to non-responders. CONCLUSION: FMT administration using the proposed regimen did not achieve statistical significance for complete CPE decolonization but was correlated with the relative abundance of specific bacterial taxa, including CPE species.

Epidemiology of Citrobacter spp. infections among hospitalized patients: a systematic review and meta-analysis.

BACKGROUND: Infections due to Citrobacter species are increasingly observed in hospitalized patients and are often multidrug-resistant. Yet, the magnitude and burden of Citrobacter spp. resistance in the hospital setting have not been reported. We aimed to evaluate the epidemiology of Citrobacter spp. infections among hospitalized patients, their main resistance patterns and Citrobacter spp. involvement in hospital outbreaks. METHODS: We conducted a systematic review and meta-analysis of published literature (PROSPERO registration Jan-2023, CRD42023390084). We searched Embase, Medline and grey literature for studies on hospitalized patients diagnosed with Citrobacter spp. infections, and nosocomial outbreaks due to Citrobacter spp. published during the years 2000-2022. We included observational, interventional, surveillance studies and outbreak reports. Outcomes of interest were the frequency of Citrobacter spp. infections among hospitalized patients and 3rd generation cephalosporin and/or carbapenem resistance percentages in these infections. We used random-effects models to generate pooled outcome estimates and evaluated risk of bias and quality of reporting of outbreaks. RESULTS: We screened 1609 deduplicated publications, assessed 148 full-texts, and included 41 studies (15 observational, 13 surveillance and 13 outbreak studies). Citrobacter spp. urinary tract- and bloodstream infections were most frequently reported, with Citrobacter freundii being the main causative species. Hospital-acquired infection occurred in 85% (838/990) of hospitalized patients with Citrobacter infection. After 2010, an increasing number of patients with Citrobacter spp. infections was reported in observational studies. Pooled frequency estimates for Citrobacter spp. infections could not be generated due to lack of data. The pooled prevalence of ESBL and carbapenemase producers among Citrobacter isolates were 22% (95%CI 4-50%, 7 studies) and 18% (95%CI 0-63%, 4 studies), respectively. An increased frequency of reported Citrobacter outbreaks was observed after 2016, with an infection/colonization ratio of 1:3 and a case-fatality ratio of 7% (6/89 patients). Common outbreak sources were sinks, toilets, contaminated food and injection material. Implemented preventive measures included environmental cleaning, isolation of positive patients and reinforcement of hand hygiene. Only seven out of 13 outbreaks (54%) were definitively controlled. CONCLUSION: This review highlights the clinical importance of endemic and epidemic Citrobacter spp. in healthcare settings. As an emerging, multidrug­resistant nosocomial pathogen it requires heightened awareness and further dedicated surveillance efforts.

Three novel Enterobacter cloacae bacteriophages for therapeutic use from Ghanaian natural waters.

Infections caused by multidrug-resistant (MDR) bacteria are a growing global concern. Enterobacter cloacae complex (ECC) species are particularly adept at developing antibiotic resistance. Phage therapy is proposed as an alternative treatment for pathogens that no longer respond to antibiotics. Unfortunately, ECC phages are understudied when compared to phages of many other bacterial species. In this Ghanaian-Finnish study, we isolated two ECC strains from ready-to-eat food samples and three novel phages from natural waters against these strains. We sequenced the genomic DNA of the novel Enterobacter phages, fGh-Ecl01, fGh-Ecl02, and fGh-Ecl04, and assessed their therapeutic potential. All of the phages were found to be lytic, easy to propagate, and lacking any toxic, integrase, or antibiotic resistance genes and were thus considered suitable for therapy purposes. They all were found to be related to T4-type viruses: fGh-Ecl01 and fGh-Ecl04 to karamviruses and fGh-Ecl02 to agtreviruses. Testing of Finnish clinical ECC strains showed promising susceptibility to these novel phages. As many as 61.1% of the strains were susceptible to fGh-Ecl01 and fGh-Ecl04, and 7.4% were susceptible to fGh-Ecl02. Finally, we investigated the susceptibility of the newly isolated ECC strains to three antibiotics - meropenem, ciprofloxacin, and cefepime - in combination with the novel phages. The use of phages and antibiotics together had synergistic effects. When using an antibiotic-phage combination, even low concentrations of antibiotics fully inhibited the growth of bacteria.

Overview on the role of dietary Spirulina platensis on immune responses against Edwardsiellosis among Oreochromis niloticus fish farms.

Edwardsiellosis is a bacterial fish disease that mostly occurs in freshwater farms and is characterized by a high mortality rate. Edwardsiella tarda strain was recovered from 17 fish out of 50 Nile tilapia, which were harboring clinical signs of systemic septicemia. The level of un-ionized ammonia (NH3) in the fish farm's water was 0.11-0.15 mg/L, which was stressful for the Nile tilapia.Sequencing of the gyrB1 gene confirmed that the isolate was E. tarda JALO4, and it was submitted to NCBI under the accession number PP449014. The isolated E. tarda harbored the virulence gene edw1 AHL-synthase (quorum sensing). In addition, the isolate was sensitive to trimethoprim and sulfamethoxazole mean while it was intermediate to florfenicol. The median lethal dose (LD50) of E. tarda JALO4 was determined to be 1.7 × 105 CFU/mL in Nile tilapia.In the indoor experiment, Nile tilapia (45.05 ± 0.4 g), which received dietary Spirulina platensis (5 and 10 g/kg fish feed), showed optimum growth and feed utilization. Meanwhile, after receiving dietary S. platensis, the fish's feed conversion ratio (FCR) was significantly enhanced compared to the control, which was 1.94, 1.99, and 2.88, respectively. The expression of immune-related genes interleukin (IL)-1ß and tumor necrosis factor (TNF)-α were upsurged in E. tarda-challenged fish with higher intensity in S. platensis groups. Dietary S. platensis at a dose of 10 g/kg fish feed could provide a relative protection level (RPL) of 22.2% Nile tilapia challenged against E. tarda. Nile tilapia experimentally infected E. tarda, drastically altering their behavior: higher operculum movement, low food apprehension, and abnormal swimming dietary S. platensis (10 g/kg fish feed) could rapidly restore normal status.It was concluded that Edwardsiellosis could alter Nile tilapia behavior with a high loss in fish population. Fish received dietary-S. platensis could rapidly restore normal behavior after E. tarda infection. It is recommended the incorporation of S. platensis at doses of 10 g/kg into the Nile tilapia diet to boost their immunity and counteract E. tarda infection.

Some virulence genes are associated with antibiotic susceptibility in Enterobacter cloacae complex.

BACKGROUND: Enterobacter cloacae complex (ECC) including different species are isolated from different human clinical samples. ECC is armed by many different virulence genes (VGs) and they were also classified among ESKAPE group by WHO recently. The present study was designed to find probable association between VGs and antibiotic susceptibility in different ECC species. METHODS: Forty-five Enterobacter isolates that were harvested from different clinical samples were classified in four different species. Seven VGs were screened by PCR technique and antibiotic susceptibility assessment was performed by disk-diffusion assay. RESULT: Four Enterobacter species; Enterobacter cloacae (33.3%), Enterobacter hormaechei (55.6%), Enterobacter kobei (6.7%) and Enterobacter roggenkampii (4.4%) were detected. Minimum antibiotic resistance was against carbapenem agents and amikacin even in MDR isolates. 33.3% and 13.3% of isolates were MDR and XDR respectively. The rpoS (97.8%) and csgD (11.1%) showed maximum and minimum frequency respectively. Blood sample isolated were highly virulent but less resistant in comparison to the other sample isolates. The csgA, csgD and iutA genes were associated with cefepime sensitivity. CONCLUSION: The fepA showed a predictory role for differentiating of E. hormaechei from other species. More evolved iron acquisition system in E. hormaechei was hypothesized. The fepA gene introduced as a suitable target for designing novel anti-virulence/antibiotic agents against E. hormaechei. Complementary studies on other VGs and ARGs and with bigger study population is recommended.

Microbiological survey and genomic analysis of Cronobacter sakazakii strains isolated from US households and retail foods.

Cronobacter species are opportunistic pathogens that are capable of causing morbidity and mortality, particularly in infants. Although the transmission dynamics involved in Cronobacter infections remain largely unknown, contaminated powdered infant formula (PIF) has been linked to 30% of Cronobacter sakazakii cases involving invasive illness in infants. As several lines of evidence have implicated the domestic environment in PIF contamination, we undertook a microbiological survey of homes (N = 263) across the US. Cronobacter spp. and C. sakazakii were isolated from 36.1% and 24.7% of US homes, respectively, with higher recovery rates observed for floor and kitchen surfaces. Multi-locus sequence typing indicated that the dominant strain was C. sakazakii ST4, the sequence type most commonly associated with neonatal meningitis. For comparison purposes, retail foods (N = 4,009) were also surveyed, with the highest contamination frequencies (10.1%-26.3%) seen for nut products, seeds, and grains/baked goods/flours. The sequence type profile of isolates recovered from homes mirrored that of isolates recovered from retail foods, with increased representation of ST1, ST4, ST13, ST17, and ST40. Analysis of 386 whole genomic sequences revealed significant diversity. Redundancies were only observed for isolates recovered from within the same domicile, and there were no identical matches with sequences archived at the NCBI pathogen database. Genes coding for putative virulence and antibiotic resistance factors did not segregate with clinically significant sequence types. Collectively, these findings support the possibility that contamination events occurring within the home should not be overlooked as a contributor to community-onset Cronobacter infections. IMPORTANCE: Cronobacter sakazakii is an opportunistic pathogen that can cause significant morbidity and mortality in neonates. Its transmission dynamics are poorly understood, though powered infant formula (PIF) is thought to be the major transmission vehicle. How the PIF becomes contaminated remains unknown. Our survey shows that roughly 1/4 of US homes are contaminated with Cronobacter sakazakii, particularly in the kitchen setting. Our analyses suggest that the domestic environment may contribute to contamination of PIF and provides insights into mitigating the risk of transmission.

ß-lactam resistant phenotypes reported by VITEK®2 advanced expert systemTM (AES) compared to whole genome sequencing in Enterobacterales from North and Latin America.

The VITEK®2 AES ß-lactam phenotypes of 488 Enterobacterales from North and Latin America generated by the VITEK®2 were compared to the resistance genotypes provided by whole genome sequencing (WGS). The AES provided phenotypic reports for 447 (91.6 %) isolates, including isolates harbouring carbapenemases (195; 43.6 %), ESBLs (103; 23.0 %) and transferable AmpCs (tAmpC; 28; 6.3 %) genes, as well as wildtype isolates (WT; 121; 27.1 %). Overall, the AES report was accurate for 433/447 (96.9 %) isolates. The AES accurately reported carbapenemase, ESBL, and tAmpC phenotypes for 93.7 %, 93.7 %, and 98.4 % of isolates, respectively, and sensitivity/specificity rates were 96.4 %/91.7 %, 98.1 %/92.4 %, 82.1 %/99.5 %, and 100 %/98.8 %. 14 isolates carrying carbapenemase (7 total; 3 KPC, 2 MBL, 2 OXA-48-like), ESBL (2), and tAmpC-encoding genes (5) were not correctly identified by AES. The AES phenotypic report detected resistance mechanisms among Enterobacterales rapidly and could significantly aid future antimicrobial stewardship initiatives and patient care.

Carbapenem-resistant Enterobacteriaceae in the livestock, humans and environmental samples around the globe: a systematic review and meta-analysis.

Carbapenem-resistant Enterobacteriaceae (CRE) have diminished treatment options causing serious morbidities and mortalities. This systematic review and meta-analysis assessed the prevalence and associated factors of Enterobacteriaceae infections in clinical, livestock and environmental settings globally. The population intervention comparison and outcome strategy was used to enroll studies using the preferred reporting system for systematic review and meta-analysis to include only cross-sectional studies. Search engines used to retrieve articles included journal author name estimator, PubMed, Google Scholar and African Journals Online (AJOL). The Newcastle-Ottawa scale was used to assess the quality of studies. Sixteen articles from 2013 to 2023 in Africa, Asia, Europe and South America were studied. The pooled prevalence of CRE was 43.06% (95% CI 21.57-66.03). Klebsiella pneumoniae (49.40%), Escherichia coli (26.42%), and Enterobacter cloacae (14.24%) were predominant. Klebsiella pneumoniae had the highest resistance with the blaKPC-2 in addition to blaNDM, blaOXA-48, blaIMP and blaVIM. The blaKPC-2 genes occurrence was associated with environmental (P-value < 0.0001) and South American studies (P-value < 0.0001), but there was no difference in the trends over time (P-value = 0.745). This study highlights the high rates of CRE infections, particularly within blaKPC production. Monitoring and surveillance programs, research and infection control measures should be strengthened. Additionally, further studies are needed to explore the mechanisms driving the predominance of specific bacterial species and the distribution of resistance genes within this bacterial family.

Carbapenemase-producing enterobacterales colonisation status does not lead to more frequent admissions: a linked patient study.

BACKGROUND: Hospitals in any given region can be considered as part of a network, where facilities are connected to one another - and hospital pathogens potentially spread - through the movement of patients between them. We sought to describe the hospital admission patterns of patients known to be colonised with carbapenemase-producing Enterobacterales (CPE), and compare them with CPE-negative patient cohorts, matched on comorbidity information. METHODS: We performed a linkage study in Victoria, Australia, including datasets with notifiable diseases (CPE notifications) and hospital admissions (admission dates and diagnostic codes) for the period 2011 to 2020. Where the CPE notification date occurred during a hospital admission for the same patient, we identified this as the 'index admission'. We determined the number of distinct health services each patient was admitted to, and time to first admission to a different health service. We compared CPE-positive patients with four cohorts of CPE-negative patients, sampled based on different matching criteria. RESULTS: Of 528 unique patients who had CPE detected during a hospital admission, 222 (42%) were subsequently admitted to a different health service during the study period. Among these patients, CPE diagnosis tended to occur during admission to a metropolitan public hospital (86%, 190/222), whereas there was a greater number of metropolitan private (23%, 52/222) and rural public (18%, 39/222) hospitals for the subsequent admission. Median time to next admission was 4 days (IQR, 0-75 days). Admission patterns for CPE-positive patients was similar to the cohort of CPE-negative patients matched on index admission, time period, and age-adjusted Charlson comorbidity index. CONCLUSIONS: Movement of CPE-positive patients between health services is not a rare event. While the most common movement is from one public metropolitan health service to another, there is also a trend for movement from metropolitan public hospitals into private and rural hospitals. After accounting for clinical comorbidities, CPE colonisation status does not appear to impact on hospital admission frequency or timing. These findings support the potential utility of a centralised notification and outbreak management system for CPE positive patients.

Molecular characteristics and evaluation of the phenotypic detection of carbapenemases among Enterobacterales and Pseudomonas via whole genome sequencing.

Background/purposes: The continuously increasing carbapenem resistance within Enterobacterales and Pseudomonas poses a threat to public health, nevertheless, the molecular characteristics of which in southern China still remain limited. And carbapenemase identification is a key factor in effective early therapy of carbapenem-resistant bacteria infections. We aimed to determine the molecular characteristics of these pathogens and compare commercial combined disc tests (CDTs) with the modified carbapenem inactivation method (mCIM) and EDTA-CIM (eCIM) in detecting and distinguishing carbapenemases using whole genome sequencing (WGS). Methods: A total of 78 Enterobacterales, 30 Pseudomonas were obtained from two tertiary hospitals in southern China. Susceptibility tests were conducted using an automated VITEK2 compact system with confirmation via the Kirby-Bauer method. The WGS was conducted on all clinical isolates and the molecular characteristics were analyzed by screening the whole genome sequences. CDTs with or without cloxacillin, mCIM, and eCIM, were performed and compared by taking WGS results as the benchmark. Results: A total of 103 carbapenem non-susceptible and 5 carbapenem susceptible bacteria were determined, with Klebsiella pneumoniae (42.7%), Pseudomonas aeruginosa (23.3%) and Escherichia coli (18.4%) being most prevalent. Carbapenemase genes were detected in 58 (56.3%) of the 103 carbapenem-non-susceptible clinical isolates, including 46 NDM, 6 KPC, 3 IMP, 1 IPM+VIM,1NDM+KPC, and 1 OXA-181. Carbapenemase-producing isolates were detected more frequently in Enterobacterales (76.3%). Among K. pneumoniae, the major sequence types were st307 and st11, while among E. coli and P. aeruginosa, the most prevalent ones were st410 and st242 respectively. For carbapenemase detection in Enterobacterales, the mCIM method achieved 100.00% (95% CI, 92.13-100.00%) sensitivity and 94.44% (70.63-99.71%) specificity (kappa, 0.96); for Pseudomonas, detection sensitivity was 100% (5.46-100.00%), and 100% (84.50-100.00%) specificity (kappa, 0.65). Commercial CDT carbapenemase detection sensitivity for Enterobacterales was 96.49% (86.84-99.39%), and 95.24% (74.13-99.75%) specificity (kappa, 0.90); for Pseudomonas, carbapenemase detection sensitivity was 100.00% (5.46-100.00%) and 37.93% (21.30-57.64%) specificity (kappa, 0.04). When cloxacillin testing was added, CDT specificity reached 84.61% (64.27-94.95%). Conclusion: The molecular epidemiology of carbapenem-non-susceptible isolates from pediatric patients in Southern China exhibited distinctive characteristics. Both the mCIM-eCIM combination and CDT methods effectively detected and differentiated carbapenemases among Enterobacterales isolates, and the former performed better than CDT among Pseudomonas.

Raoultella planticola Urinary Tract Infection Presenting as Hyperbilirubinemia in a 3-Day-Old Infant.

Raoultella planticola is a Gram-negative, aerobic, nonmotile bacterium that is ubiquitous in the environment usually implicated in opportunistic infections. There have been very few reported cases of Raoultella planticola infection in the pediatric population. Most of these reports have been in cases of neonatal septicemia. This case report describes a case of a 3-day-old Hispanic full-term male that presented with recalcitrant hyperbilirubinemia despite maximal phototherapy found to have urinary tract infection with Raoultella planticola on multiple cultures. The patient's hyperbilirubinemia appropriately responded to treatment of the UTI. This report highlights that, albeit rare, neonatal UTI can present as recalcitrant hyperbilirubinemia. Raoultella planticola is a rare organism that is normally found in the environment but may be a bona fide etiologic agent in neonatal UTI.

Integrated Analysis of Patient Networks and Plasmid Genomes to Investigate a Regional, Multispecies Outbreak of Carbapenemase-Producing Enterobacterales Carrying Both blaIMP and mcr-9 Genes.

BACKGROUND: Carbapenemase-producing Enterobacterales (CPE) are challenging in healthcare, with resistance to multiple classes of antibiotics. This study describes the emergence of imipenemase (IMP)-encoding CPE among diverse Enterobacterales species between 2016 and 2019 across a London regional network. METHODS: We performed a network analysis of patient pathways, using electronic health records, to identify contacts between IMP-encoding CPE-positive patients. Genomes of IMP-encoding CPE isolates were overlaid with patient contacts to imply potential transmission events. RESULTS: Genomic analysis of 84 Enterobacterales isolates revealed diverse species (predominantly Klebsiella spp, Enterobacter spp, and Escherichia coli); 86% (72 of 84) harbored an IncHI2 plasmid carrying blaIMP and colistin resistance gene mcr-9 (68 of 72). Phylogenetic analysis of IncHI2 plasmids identified 3 lineages showing significant association with patient contacts and movements between 4 hospital sites and across medical specialties, which was missed in initial investigations. CONCLUSIONS: Combined, our patient network and plasmid analyses demonstrate an interspecies, plasmid-mediated outbreak of blaIMPCPE, which remained unidentified during standard investigations. With DNA sequencing and multimodal data incorporation, the outbreak investigation approach proposed here provides a framework for real-time identification of key factors causing pathogen spread. Plasmid-level outbreak analysis reveals that resistance spread may be wider than suspected, allowing more interventions to stop transmission within hospital networks.SummaryThis was an investigation, using integrated pathway networks and genomics methods, of the emergence of imipenemase-encoding carbapenemase-producing Enterobacterales among diverse Enterobacterales species between 2016 and 2019 in patients across a London regional hospital network, which was missed on routine investigations.

Interpreting the results of rapid molecular diagnostic tests for carbapenem-resistant Enterobacterales infection: current clinical perspective while waiting for further evidence.

INTRODUCTION: Carbapenem-resistant Enterobacterales (CRE) causing severe infections in humans have represented an important challenge for clinicians worldwide during the past two decades. AREAS COVERED: Novel ß-lactams and ß-lactam/ß-lactamase inhibitor combinations have led to a shift in the first-line approach to the treatment of severe CRE infections from polymyxin-based regimens to treatment with less toxic agents. This new scenario offers the opportunity to apply rapid molecular diagnostic tests for CRE infection to identify different types of carbapenemases. Herein, the authors provide an overview of this subject and follow it with their expert perspectives. EXPERT OPINION: When considering studies actually measuring the clinical impact of rapid molecular tests in real-life scenarios, high certainty evidence from randomized controlled trials is still limited and not focused on CRE infections. Nonetheless, it is indisputable that rapid molecular tests have been shown to impact early therapeutic choices (in terms of both escalation and de-escalation) when used in real-life settings, thus issues in the clinical interpretation of their results are already relevant. Overall, increased expertise is required for the appropriate interpretation of rapid molecular tests for personalized antibiotic selection by understanding their strengths and limitations.

Clinical differences between Raoultella spp. and Klebsiella oxytoca.

Purpose: Raoultella spp. is a genus of bacteria that is known to be closely related to Klebsiella. It has been debated whether Raoultella should be reclassified as a subgroup of Klebsiella. The aim of this study is to compare clinical aspects of Raoultella and Klebsiella oxytoca, a species of Klebsiella that is known to be bacteriologically similar to Raoultella spp. Methods: Using data collected at a tertiary care hospital in the United States, we identified 43 patients with Raoultella infection and 1173 patients with Klebsiella oxytoca infection. We compared patient demographics (age and sex), hospitalization status, isolation sites and antibiotic resistance profiles between the two species. Results: There was no significant difference in patient demographics between the two bacteria species. The proportions of intensive care unit (ICU) admission were higher among patients with Raoultella infection (p=0.008). The most common site of isolation was urine for both species (39.5% of all patients with Raoultella spp. vs. 59.3% for K. oxytoca). The second most common site of isolation was blood stream for Raoultella spp. (23.3%) and respiratory tract for K. oxytoca (10.8%). Except for the high proportion of resistant isolates of Raoultella spp. for Trimethoprim/sulfamethoxazole, the antibiotic susceptibility profiles were similar between the two bacteria species. Both were susceptible to ciprofloxacin and meropenem. Conclusion: While there are no significant differences in the patient demographics and antibiotic susceptibility profiles between Raoultella spp. and K. oxytoca, Raoultella may cause more serious infection requiring ICU admissions. Also, Raoultella may cause blood stream infection more frequently than K. oxytoca.

Exogenous NADH promotes the bactericidal effect of aminoglycoside antibiotics against Edwardsiella tarda.

The global surge in multidrug-resistant bacteria owing to antibiotic misuse and overuse poses considerable risks to human and animal health. With existing antibiotics losing their effectiveness and the protracted process of developing new antibiotics, urgent alternatives are imperative to curb disease spread. Notably, improving the bactericidal effect of antibiotics by using non-antibiotic substances has emerged as a viable strategy. Although reduced nicotinamide adenine dinucleotide (NADH) may play a crucial role in regulating bacterial resistance, studies examining how the change of metabolic profile and bacterial resistance following by exogenous administration are scarce. Therefore, this study aimed to elucidate the metabolic changes that occur in Edwardsiella tarda (E. tarda), which exhibits resistance to various antibiotics, following the exogenous addition of NADH using metabolomics. The effects of these alterations on the bactericidal activity of neomycin were investigated. NADH enhanced the effectiveness of aminoglycoside antibiotics against E. tarda ATCC15947, achieving bacterial eradication at low doses. Metabolomic analysis revealed that NADH reprogrammed the ATCC15947 metabolic profile by promoting purine metabolism and energy metabolism, yielding increased adenosine triphosphate (ATP) levels. Increased ATP levels played a crucial role in enhancing the bactericidal effects of neomycin. Moreover, exogenous NADH promoted the bactericidal efficacy of tetracyclines and chloramphenicols. NADH in combination with neomycin was effective against other clinically resistant bacteria, including Aeromonas hydrophila, Vibrio parahaemolyticus, methicillin-resistant Staphylococcus aureus, and Listeria monocytogenes. These results may facilitate the development of effective approaches for preventing and managing E. tarda-induced infections and multidrug resistance in aquaculture and clinical settings.

Pantoea dispersa peritoneal dialysis catheter-related infection.

Enteric gram-negative bacteria-associated peritoneal dialysis (PD) peritonitis is common. These organisms are such as Escherichia coli, Klebsiella and Enterobacter species. Pantoea dispersa belongs to the order Enterobacterales, it has known benefits and a role in agricultural and environmental biotechnology. Pantoea dispersa, although still relatively rare, is being increasingly recognised to cause human infections. We are reporting a case of PD peritonitis caused by Pantoea dispersa in a kidney failure patient on continuous ambulatory peritoneal dialysis (CAPD). His peritonitis was treated well with intraperitoneal antibiotics and the patient can resume his CAPD therapy. The increasing reports of Pantoea dispersa-related human infections warrant concerns, both in immunocompromised and immunocompetent patients.

The impact of colistin-based regimens on mortality compared to other antimicrobials in patients with carbapenem-resistant Enterobacterales bacteremia in South African hospitals: a cross-sectional study.

BACKGROUND: Treatment of carbapenem-resistant Enterobacterales (CRE) infections in low-resource settings is challenging particularly due to limited treatment options. Colistin is the mainstay drug for treatment; however, nephrotoxicity and neurotoxicity make this drug less desirable. Thus, mortality may be higher among patients treated with alternative antimicrobials that are potentially less efficacious than colistin. We assessed mortality in patients with CRE bacteremia treated with colistin-based therapy compared to colistin-sparing therapy. METHODS: We conducted a cross-sectional study using secondary data from a South African national laboratory-based CRE bacteremia surveillance system from January 2015 to December 2020. Patients hospitalized at surveillance sentinel sites with CRE isolated from blood cultures were included. Multivariable logistic regression modeling, with multiple imputations to account for missing data, was conducted to determine the association between in-hospital mortality and colistin-based therapy versus colistin-sparing therapy. RESULTS: We included 1 607 case-patients with a median age of 29 years (interquartile range [IQR], 0-52 years) and 53% (857/1 607) male. Klebsiella pneumoniae caused most of the infections (82%, n=1 247), and the most common carbapenemase genes detected were blaOXA-48-like (61%, n=551), and blaNDM (37%, n=333). The overall in-hospital mortality was 31% (504/1 607). Patients treated with colistin-based combination therapy had a lower case fatality ratio (29% [152/521]) compared to those treated with colistin-sparing therapy 32% [352/1 086]) (p=0.18). In our imputed model, compared to colistin-sparing therapy, colistin-based therapy was associated with similar odds of mortality (adjusted odds ratio [aOR] 1.02; 95% confidence interval [CI] 0.78-1.33, p=0.873). CONCLUSION: In our resource-limited setting, the mortality risk in patients treated with colistin-based therapy was comparable to that of patients treated with colistin-sparing therapy. Given the challenges with colistin treatment and the increasing resistance to alternative agents, further investigations into the benefit of newer antimicrobials for managing CRE infections are needed.