OBJECTIVE: KPC-2-producing Pseudomonas aeruginosa high-risk sequence type (ST) 463 is increasingly prevalent in China and poses severe threats to public health. In this study, we aimed to investigate within-host adaptive evolution of this clone during therapy.
METHODS: Using nine serial respiratory isolates from a post-lung transplantation patient undergoing multiple antibiotic treatments, we conducted genomic, transcriptomic and phenotypic analyses to uncover the adaptive mechanisms of a KPC-2-producing ST463 P. aeruginosa strain.
RESULTS: The early-course isolates exhibited low-level resistance to ceftazidime/avibactam (CZA), facilitated by the blaKPC-2 gene\'s presence on both chromosome and plasmid, and its overexpression. Comparative genomic analysis revealed that chromosomal integration of blaKPC-2 resulted from intracellular replicative transposition of the plasmid-derived IS26-blaKPC-2-IS26 composite transposon. As the infection progressed, selective pressures, predominantly from antibiotic interventions and host immune response, led to significant genomic and phenotypic changes. The late-course isolates developed a Δ242-GT-243 deletion in plasmid-encoded blaKPC-2 (blaKPC-14) after sustained CZA exposure, conferring high-level CZA resistance. Increased expression of pili and extracellular polysaccharides boosted biofilm formation. A D143N mutation in the global regulator vfr rendered the strain aflagellate by abrogating the ability of fleQ to positively regulate flagellar gene expression. The enhancement of antibiotic resistance and immune evasion collaboratively facilitated the prolonged survival of ST463 P. aeruginosa within the host.
CONCLUSIONS: Our findings highlight the remarkable capacity of ST463 P. aeruginosa in adapting to the dynamic host pressures, supporting its persistence and dissemination in healthcare.

Vancomycin has been reported to cause vancomycin flushing reaction (VFR), a hypersensitivity reaction that mostly occurs after intravenous administration. The incidence of VFR in a patient receiving intraperitoneal vancomycin is rare. We report a case of a female peritoneal dialysis (PD) patient with a PD-related peritonitis who developed VFR after intraperitoneal administration of 2000 mg vancomycin. Seventy-five minutes after instillation, she developed flushing, a pruritic erythema on the upper body and swelling of the lips. Blood results revealed a vancomycin plasma concentration of 54.8 mg/L and a normal tryptase level. During a relapse of her PD-related peritonitis, vancomycin was successfully reintroduced in a 50% reduced dose. No symptoms of VFR developed, and the corresponding vancomycin plasma concentration was 33.6 mg/L. Intraperitoneal treatment was continued with 500 mg vancomycin every 2-3 days with frequently measured, adequate trough levels ranging from 15-22 mg/L. This case illustrates the risk factors for the development of VFR after intraperitoneal administration of vancomycin, namely a high and concentrated loading dose together with a low body weight, a fast peritoneal transport state and peritonitis. Reintroduction of vancomycin after occurrence of VFR is safe, but a lower loading dose or a slower instillation rate is recommended.

Despite the number of cholera outbreaks reported worldwide, only a few cases are recorded among returning European travellers. We describe the case of a 41-year-old male, returning to Italy after a stay in Bangladesh, his origin country, who presented with watery diarrhoea. Vibrio cholerae and norovirus were detected in the patient\'s stools via multiplex PCR methods. Direct microscopy, Gram staining, culture and antibiotic susceptibility tests were performed. The isolates were tested using end-point PCR for the detection of potentially enteropathogenic V. cholera. Serotype and cholera toxins identification were carried out. Whole genome sequencing and bioinformatics analysis were performed, and antimicrobial resistance genes identified. A phylogenetic tree with the most similar genomes of databases previously described was built. Sample of the food brought back by the patient were also collected and analysed. The patient was diagnosed with V. cholerae O1, serotype Inaba, norovirus and SARS-CoV-2 concomitant infection. The isolated V. cholerae strain was found to belong to ST69, encoding for cholera toxin, ctxB7 type and was phylogenetically related to the 2018 outbreak in Dhaka, Bangladesh. Adopting a multidisciplinary approach in a cholera non-endemic country ensured rapid and accurate diagnosis, timely clinical management, and epidemiological investigation at national and international level.

Pseudomonas aeruginosa is a leading cause of hospital-acquired infections. Treatment of P. aeruginosa infections is difficult given its multiple virulence mechanisms, intrinsic antibiotic resistance mechanisms, and biofilm-forming ability. Auranofin, an approved oral gold compound for rheumatoid arthritis treatment, was recently reported to inhibit the growth of multiple bacterial species. Here, we identify P. aeruginosa\'s global virulence factor regulator Vfr as one target of auranofin. We report the mechanistic insights into the inhibitory mechanism of auranofin and gold(I) analogues to Vfr through structural, biophysical, and phenotypic inhibition studies. This work suggests that auranofin and gold(I) analogues have potential to be developed as anti-virulence drugs against P. aeruginosa.

Delayed treatment is associated with a higher risk of severe malaria. In malaria-endemic areas, the main factors associated with delay in seeking healthcare are low educational level and traditional beliefs. In imported malaria, determinants of delay in seeking healthcare are currently unknown.
We studied all patients presenting with malaria, from 1 January 2017 to 14 February 2022, in the hospital of Melun, France. Demographic and medical data were recorded for all patients, and socio-professional data were recorded for a subgroup of hospitalized adults. Relative-risks and 95% confidence intervals were determined using univariate analysis by cross-tabulation.
There were 234 patients included, all travelling from Africa. Among them, 218 (93%) were infected with P. falciparum, 77 (33%) had severe malaria, 26 (11%) were <18 years old and 81 were included during the SARS-CoV-2 pandemic. There were 135 hospitalized adults (58% of all patients). The median time to hospital admission (THA) , defined by the period from onset of symptoms to arrival at hospital, was 3 days (IQR = 2-5). A THA ≥3 days tended to be more frequent in travellers visiting friends and relatives (VFR; RR = 1.44, 95% CI = [1.0-2.05], P = 0.06), while it was less frequent in children and teenagers (RR = 0.58, 95% CI = [0.39-0.84], P = 0.01). Gender, African background, unemployment, living alone and absence of referring physician were not associated with delay in seeking healthcare. Consulting during the SARS-CoV-2 pandemic was neither associated with a longer THA nor with a higher rate of severe malaria.
In contrast to an endemic area, socio-economic factors did not impact on delay in seeking healthcare in imported malaria. Prevention should focus on VFR subjects, who tend to consult later than other travellers.

The opportunistic pathogen Pseudomonas aeruginosa relies upon type IV pili (Tfp) for host colonization and virulence. Tfp are retractile surface appendages that promote adherence to host tissue and mediate twitching motility, a form of surface-associated translocation. Tfp are composed of a major structural pilin protein (PilA), several less abundant, fiber-associated pilin-like proteins (FimU, PilV, PilW, PilX, and PilE), and a pilus-associated tip adhesin and surface sensor (PilY1). Several proteins critical for Tfp biogenesis and surface sensing are encoded by the fimU-pilVWXY1Y2E operon. Tfp biogenesis is regulated by the global transcription factor Vfr and its allosteric effector, cyclic AMP (cAMP). Our investigation into the basis for reduced Tfp production in cAMP/vfr mutants revealed a defect in the expression of the fimU operon. We found that cAMP/Vfr activation of the fimU operon occurs via direct binding of Vfr to a specific fimU promoter sequence. We also refined the role of the AlgZ/AlgR two-component system in fimU regulation by demonstrating that phosphorylation of the response regulator AlgR is required for maximal binding to the fimU promoter region in vitro. Vfr also regulates expression of the algZR operon, revealing an indirect regulatory loop affecting fimU operon transcription. Overall, these results demonstrate that two linked but independent regulatory systems couple the expression of Tfp biogenesis and surface sensing genes and highlight the regulatory complexity governing expression of P. aeruginosa virulence factors. IMPORTANCE Pseudomonas aeruginosa is an opportunistic pathogen responsible for a wide range of infections. An extensive repertoire of virulence factors aid in P. aeruginosa pathogenesis. Type IV pili (Tfp) play a critical role in host colonization and infection by promoting adherence to host tissue, facilitating twitching motility and mediating surface-associated behaviors. The fimU operon encodes several pilus-associated proteins that are essential for proper Tfp function and surface sensing. In this study, we report that linked but independent regulatory systems dictate Tfp biogenesis. We also demonstrated the importance of different phosphorylation states of the AlgZ/AlgR two-component system and its role in Tfp biogenesis. Overall, this study furthers our understanding of the complex regulatory mechanisms that govern the production of a critical and multifaceted virulence factor.

BACKGROUND: The study aimed to analyse the likelihood of imported malaria in people with a suggestive clinical picture and its distinctive characteristics in a hospital in the south of Madrid, Spain.
METHODS: Observational retrospective study that consisted of a review of all medical files of patients with any malaria test registered at Móstoles University Hospital between April 2013 and April 2018. All suspected malaria cases were confirmed by Plasmodium spp. polymerase chain reaction (PCR).
RESULTS: Of the 328 patients with suspected malaria (53.7% migrant-travellers; 38.7% visitors; 7.6% travellers), 108 cases were confirmed (101 by Plasmodium falciparum), accounting for a 33% positive sample rate. Sixteen cases were diagnosed only by PCR. Patients with malaria, compared to those without, presented predominantly with fever (84% vs. 65%), were older (34 vs. 24 years), sought medical attention earlier (17d vs. 32d), had a greater number of previous malaria episodes (74% vs. 60%), lower levels of platelets (110,500µL vs. 250,000µL), and higher of bilirubin (0.6 mg/dL vs. 0.5 mg/dL). Severe malaria was present in 13 cases; no deaths were recorded. Malaria diagnosis showed a bimodal distribution with two peaks: June to September and November to January.
CONCLUSIONS: Malaria is still a common diagnosis among febrile patients coming from the tropics specially among migrant travellers. Fever, thrombocytopenia, and/or high bilirubin levels should raise suspicion for this parasitic infection. Prompt diagnosis is crucial to avoid severe cases and deaths.

Background: Italy is considered an area with very low HAV (hepatitis A virus) endemicity. Currently in Italy the anti-HAV vaccine is recommended only for specific risk groups and there is no universal vaccination program. The aim of this study was to assess the level of immunity against hepatitis A in a sample of children and adolescents from the province of Florence. Methods: A total of 165 sera were collected from subjects aged 1 to 18 years, proportionally selected according to the general population size and stratified by age and sex. A qualitative evaluation of anti-HAV antibodies was performed using the enzyme-linked immunosorbent assay (ELISA). Anamnestic and vaccination status data were also collected. Results: Our study showed a hepatitis A seroprevalence of 9.1% in the enrolled population. A statistically significant difference in the prevalence of anti-HAV was found between Italian and non-Italian subjects. About half of the population having anti-HAV antibodies was reported to be vaccinated, and no cases of hepatitis A were found. Conclusions: The data from our study confirmed Tuscany as an area with low HAV endemicity and showed that hepatitis A seroprevalence is significantly higher in foreign children and adolescents. The presence of more seropositive subjects than those vaccinated was probably due to a natural immunization achieved through a subclinical infection and/or to underreporting of the surveillance systems.

Pseudomonas aeruginosa is a wide-spread γ-proteobacterium that produces the biosurfactant rhamnolipid that has a great commercial value due to excellent properties of low toxicity and high biodegradability. However, this bacterium is an opportunist pathogen that constitutes an important health hazard due to its production of virulence-associated traits and its high antibiotic resistance. Thus, it is highly desirable to have a non-virulent P. aeruginosa strain for rhamnolipid production. It has been reported that strain ATCC 9027 is avirulent in mouse models of infection, and it is still able to produce rhamnolipid. Thus, it has been proposed to be suitable for it industrial production, since it encodes a defective LasR quorum sensing (QS) transcriptional regulator that is the head of this regulatory network. However, the restoration of virulence factor production by overexpression of rhlR (the gene encoding a QS-transcriptional regulator which is under the transcriptional control of LasR) is not sufficient to restore its virulence in mice. It is desirable to obtain a deeper understanding of ATCC 9027 attenuated-virulence phenotype and to assess the safety of this strain to be used at an industrial scale. In this work we determined whether increasing the expression of the pore-forming toxin encoded by the exlBA operon in strain ATCC 9027 had an impact on its virulence using Galleria mellonella and mouse models of infections. We increased the expression of the exlBA operon by overexpressing from a plasmid its transcriptional activator Vfr or of the Vfr ligand cyclic AMP produced by CyaB. We found that in G. mellonella ATCC 9027/pUCP24-vfr and ATCC 9027/pUCP24-cyaB gained a virulent phenotype, but these strains remained avirulent in murine models of P. aeruginosa infection. These results reinforce the possibility of using ATCC 9027 for industrial biosurfactants production.

To evaluate if cost and availability of antimalarials are barriers to malaria chemoprophylaxis and treatment, we surveyed retail pharmacies in Minneapolis/Saint Paul and New York City on the price and stocking of antimalarials. We demonstrated extreme price variability among pharmacies and limited availability for some recommended antimalarials.