Mitochondrial DNA variation in Aedes aegypti (Diptera: Culicidae) mosquitoes from Jeddah, Saudi Arabia.

Wolbachia (Hertig 1936) (Rickettsiales: Ehrlichiaceae) has emerged as a valuable biocontrol tool in the fight against dengue by suppressing the transmission of the virus through mosquitoes. Monitoring the dynamics of Wolbachia is crucial for evaluating the effectiveness of release programs. Mitochondrial (mtDNA) markers serve as important tools for molecular tracking of infected mitochondrial backgrounds over time but require an understanding of the variation in release sites. In this study, we investigated the mitochondrial lineages of Aedes aegypti (Linnaeus 1762) in Jeddah, Saudi Arabia, which is a prospective release site for the "wAlbBQ" Wolbachia-infected strain of this mosquito species. We employed a combination of comprehensive mitogenomic analysis (including all protein-coding genes) and mtDNA marker analysis (cox1 and nad5) using data collected from Jeddah. We combined our mitogenome and mtDNA marker data with those from previous studies to place mitochondrial variation in Saudi Arabia into a broader global context. Our findings revealed the presence of 4 subclades that can be broadly categorized into 2 major mitochondrial lineages. Ae. aegypti mosquitoes from Jeddah belonged to both major lineages. Whilst mitogenomic data offered a higher resolution for distinguishing Jeddah mosquitoes from the wAlbBQ strain, the combination of cox1 and nad5 mtDNA markers alone proved to be sufficient. This study provides the first important characterization of Ae. aegypti mitochondrial lineages in Saudi Arabia and offers essential baseline information for planning future molecular monitoring efforts during the release of Wolbachia-infected mosquitoes.

Plasmodium falciparum formins are essential for invasion and sexual stage development.

The malaria parasite uses actin-based mechanisms throughout its lifecycle to control a range of biological processes including intracellular trafficking, gene regulation, parasite motility and invasion. In this work we assign functions to the Plasmodium falciparum formins 1 and 2 (FRM1 and FRM2) proteins in asexual and sexual blood stage development. We show that FRM1 is essential for merozoite invasion and FRM2 is required for efficient cell division. We also observed divergent functions for FRM1 and FRM2 in gametocyte development. Conditional deletion of FRM1 leads to a delay in gametocyte stage progression. We show that FRM2 controls the actin and microtubule cytoskeletons in developing gametocytes, with premature removal of the protein resulting in a loss of transmissible stage V gametocytes. Lastly, we show that targeting formin proteins with the small molecule inhibitor of formin homology domain 2 (SMIFH2) leads to a multistage block in asexual and sexual stage parasite development.

A case of Neurospora sitophila causing PD peritonitis.

We describe a rare case of fungal peritoneal dialysis (PD) peritonitis caused by the ascomycete fungus Neurospora sitophila (N. sitophila). The patient had little response to initial antibiotics and PD catheter removal was necessary for source control. The fungal biomarker ß-d-glucan (BDG) was positive prior to N. sitophila being cultured and remained positive for 6 months after discharge. Use of BDG early in the assessment of PD peritonitis may reduce time to definitive therapy in fungal peritonitis.

Developing Wolbachia-based disease interventions for an extreme environment.

Aedes aegypti mosquitoes carrying self-spreading, virus-blocking Wolbachia bacteria are being deployed to suppress dengue transmission. However, there are challenges in applying this technology in extreme environments. We introduced two Wolbachia strains into Ae. aegypti from Saudi Arabia for a release program in the hot coastal city of Jeddah. Wolbachia reduced infection and dissemination of dengue virus (DENV2) in Saudi Arabian mosquitoes and showed complete maternal transmission and cytoplasmic incompatibility. Wolbachia reduced egg hatch under a range of environmental conditions, with the Wolbachia strains showing differential thermal stability. Wolbachia effects were similar across mosquito genetic backgrounds but we found evidence of local adaptation, with Saudi Arabian mosquitoes having lower egg viability but higher adult desiccation tolerance than Australian mosquitoes. Genetic background effects will influence Wolbachia invasion dynamics, reinforcing the need to use local genotypes for mosquito release programs, particularly in extreme environments like Jeddah. Our comprehensive characterization of Wolbachia strains provides a foundation for Wolbachia-based disease interventions in harsh climates.

Spread of Covid-19 in hemodialysis centres; the effects of ventilation and communal transport.

AIMS: Hemodialysis (HD) patients are at increased risk of respiratory infections, due to increased use of communal travel, waiting areas, close proximity to others when dialysing, and contact with healthcare personnel. We wished to determine the major factors associated with transmission of COVID-19 within dialysis centres. METHODS: We compared the differences in the number of COVID-19 infections in patients and staff in 5 dialysis centres during the 1st COVID-19 pandemic between March and June 2020, and analyzed differences between centres. Isolation policies and infection control practices were identical between centres. RESULTS: 224 (30.3%) patients tested positive for COVID-19, by reverse transcriptase polymerase chain reaction, ranging from 4.8% (centre 1 size 55 patients) to 41.5% (centre 5-248 patients) p = 0.007. Communal transport had a significant effect; with 160 of 452 (35.4%) patients using communal testing positive compared to 22.2% of those not using communal transport (X214.5, p < 0.001). Staff sickness varied; 35 of 36 (97.3% centre 5) dialysis staff contracting COVID-19, compared to 60% from centre 4 (189 patients 30 staff) (p < 0.001). Whereas centre 5 had no natural ventilation, and fan assisted ventilation did not meet standards for air changes and air circulation, centre 4 met ventilation standards. CONCLUSIONS: Although there are many potential risk factors accounting for the increased risk of COVID-19 infection in hemodialysis patients, we found that differences in communal transport for patients and ventilation between centres was a major contributor accounting for the differences in patients testing positive for COVID-19 and staff sickness rates. This has important practical applications for designing kidney dialysis centres.

The Value of Perfusion Fluid Culture Analysis in Deceased Donor Renal Transplants: A 10-Year Single-Center Experience.

Microbiological analysis of kidney perfusion/transport solution is not routinely performed in all transplant centers. This paper gives a 10-year descriptive single-center experience of the routine culture of perfusion fluid in deceased donor renal transplant recipients as well as the prophylactic treatment of certain organisms if identified. Data were collected retrospectively on all deceased donor transplants performed between 2009 and 2018. Organisms detected were classified as either pathologic, of uncertain pathogenicity, or contaminants. Treatment was guided by the microbiology team. A total of 661 specimens were analyzed. Organisms were cultured in 168 of 661 (25.4%) of these samples. The most frequent organisms identified were skin and oral flora (n = 95, 42%). The majority of organisms identified (131 of 226, 58%) necessitated prophylactic treatment on the advice of our microbiology department. On 7 (4.2%) occasions, the perfusion fluid cultures grew organisms not covered by the routine antimicrobial prophylaxis, and on 15 occasions Candida albicans was isolated. Candida isolates were treated preemptively with 1 month of antifungal treatment. There were no infective sequelae in this group.

Epidemiology and impact of bloodstream infections among kidney transplant recipients: A retrospective single-center experience.

BACKGROUND: Bloodstream infection (BSI) represents an important source of morbidity and mortality, as well as an increasing therapeutic challenge, among solid organ transplant recipients. Understanding the epidemiological and microbiological characteristics of BSI following renal transplantation is paramount to the implementation of appropriate preventative and therapeutic measures. METHODS: We conducted a retrospective review of all BSI episodes occurring between July 2009 and April 2016 in adult patients, who received a renal transplant at Royal Free London hospital. RESULTS: A total of 116 episodes of BSI occurred in 87 patients, 43 (49.4%) of them men. The mean age at BSI was 54.37 ± 12.81 years. Late-onset BSI (>12 months post transplant) represented 55.2%, with the median time to BSI being 16.28 month. Sixty-seven patients had single BSI and 20 had recurrent episodes. Enterobacteriaceae were responsible for 73.7% of BSI, with Escherichia coli the commonest causative organism (46.6%). The urinary tract was the most frequent source of infection in 56.9%. Among the E. coli infections, 100% of the tested isolates were sensitive to meropenem, ertapenem, tigecycline, and fosfomycin, and >90% were sensitive to piperacillin-tazobactam, amikacin, and colistin. Lower susceptibility rates were encountered for ceftriaxone (70.6%), amoxicillin-clavulanic acid (48.1%), cotrimoxazole (40.4%), trimethoprim (37.3%), and amoxicillin (21.6%). During BSI, the median serum creatinine increased from a reference of 131 µmol/L to a peak of 219 µmol/L. Acute kidney injury (AKI) complicated 75/116 BSI episodes (64.7%)-stage 1: 34, stage 2: 31, and stage 3 AKI: 10 episodes. After 3 months, the median creatinine remained elevated at 146 µmol/L. The 3-month mortality rate was 8% (7/87), and the death-censored graft loss was 6.9% (6/87). No significant difference was seen between BSI of urinary and non-urinary sources in the incidence of AKI (χ2  = 0.24, P = .6) or the percentage of creatinine change between baseline and peak and 3-month creatinines (P = .2 and .7 respectively). CONCLUSIONS: Urinary tract infection remains the commonest source of systemic infection among kidney transplant recipients and resistance to commonly used frontline antibiotics is common; thus, prevention and early detection are paramount. The appropriate choice of initial empirical antibiotic is vital to improve the outcome. Each unit needs to understand the epidemiology of organisms causing BSI in their transplant patients and their antibiotic susceptibilities.

Sensitivity and specificity of Matrix-Associated Laser Desorption/Ionization - Time of Flight Mass Spectrometry (MALDI-TOF MS) in discrimination at species level for Acinetobacter bacteremia.

We aimed to establish the role of MALDI-TOF MS on species discrimination of phenotypically indistinguishable A. baumannii, A. pittii and A. nosocomialis. Compared to multiplex PCR, the gold standard, MALDI-TOF MS yielded a high sensitivity for A. baumannii (97.9%) and specificity for A. pittii (98.9%) and A. nosocomialis (100%).

Infection Rates Following Buttonhole Cannulation in Hemodialysis Patients.

Arteriovenous fistula (AVF) is the preferred access for hemodialysis (HD). Buttonhole (BH) needling has increased following the introduction of "blunt" fistula needles. Although some reported advantages for BH needling, others have reported increased infection risk. As such we reviewed our center practice, and the effect of both nasal screening and eradication and re-education and training programs. We audited the outcomes of 881 HD patients dialyzed between November 2009 and May 2012, divided into three groups: 175 dialyzing exclusively by central venous catheter (CVC), 478 exclusively by area needling AVF (AVF) and 219 by BH. There were 31 Staphylococcus aureus bacteremias (SABs); 14 (45.2%) dialyzing with CVCs, 12 (38.7%) BH and five (16.1%) AVF. The 30 day mortality rate for SAB was 7.5% with a complication rate of 22.6%. The hazard ratio for first SAB was significantly greater for both CVC and BH access compared to AVF (5.3 (95% CI -1.9-18.6), P < 0.001 and 3.6 (1.3-96), P = 0.011, respectively). During the study SAB rates per 1000 CVC days were 0.21, compared to 0.15 for BH. After major re-education and asepsis technique campaigns the SAB rate for BH fell to 0.06, but quickly returned to 0.17. Extending BH needling to all our dialysis centers, SAB infection rates increased to those not dissimilar to CVC access. Despite re-education programs coupled with a strict asepsis policy and active SA eradication, followed by audit cycles, the increased infection risk with BH remained, such that we have limited BH to self-care patients.

Arteriovenous fistula survival with buttonhole (constant site) cannulation for hemodialysis access.

Buttonhole needling for arteriovenous fistulae (AVF) has increased in popularity among dialysis centers. Concerns have been raised about the risks of infection, so we reviewed our experience of buttonhole needling in 227 adult patients on hemodialysis. The mean buttonhole AVF survival was 27.0 months, in 227 patients, 61.1% male, mean age 63.8 ± 15.5 years, 45.8% with diabetes mellitus, median dialysis vintage 19 months (6.5-42.8). Ninety-six patients transferred to rope ladder AVF cannulation, because of cannulation failure in 25%, persistent bleeding at the needling site in 24%, fistula thrombosis in 14%, and infections in 15%. Because of persistent methicillin-sensitive Staphylococcus aureus (MSSA) or methicillin-resistant S. aureus (MRSA) colonization, 18.8% discontinued buttonhole needling. Transfer from buttonhole needling was more common for people with diabetes (X = 6.57; p = 0.035), older patients (odds ratio, 0.985; p = 0.007), and persistent MSSA/MRSA colonization (odds ratio, 0.88; p = 0.037). Eleven episodes of suspected buttonhole S. aureus bacteremia occurred giving a bacteremia rate of 2.94 per 100 patient years, and 15 local infections giving an infection rate of 4.01 per 100 patient years. In this large series of buttonhole AVF access, although infection rates were increased, more patients discontinued buttonhole needling because of technical cannulation problems and persistent bleeding from needle tracks.

Candida nivariensis isolated from a renal transplant patient with persistent candiduria-Molecular identification using ITS PCR and MALDI-TOF.

We report on the isolation of Candida nivariensis from a renal transplant patient with persistent candiduria. Biochemical profiling misidentified isolates as Candida glabrata (3/5) and Candida inconspicua (2/5). All isolates produced white colonies on CHROMagar(™) Candida medium. Internal transcribed spacer (ITS) ribosomal gene sequence analysis and MALDI-TOF-MS analysis (Bruker Biotyper(™) 2.0) identified all isolates as C. nivariensis, demonstrating the utility of MALDI-TOF as a rapid, accurate approach for the identification of cryptic Candida species.

'An unusual response of dental sepsis to antibiotics: parallels with the Jarisch-Herxheimer reaction'.

Spreading odontogenic infections are a common source of hospital admissions to Oral and Maxillofacial Surgery (OMFS) units. This report describes an unusual reaction to routine treatment for a spreading odontogenic infection in a healthy male with no known allergies, requiring the patient to be managed supportively in the resuscitation room. The patient deteriorated rapidly after the administration of paracetamol, intravenous fluids, steroids and antibiotics, demonstrating delusional behaviour, fever, rigors, tachycardia and hypoxia. Fever associated with sepsis can lead to confusional states, but similar symptoms have been described in the literature as a reaction to antibiotic therapy known as Jarisch-Herxheimer (J-H) reaction. This is potentially the first time a J-H like reaction has been described in the context of dental sepsis. The authors feel that the OMFS team should be aware of possible sequelae of medical therapy in patients with acute dental sepsis and be confident in their management of these complications.