Antibody-Mediated Serum Resistance Protects Pseudomonas aeruginosa During Bloodstream Infections.

BACKGROUND: Pseudomonas aeruginosa is a frequent pathogen isolated from bacterial bloodstream infection (BSI) and is associated with high mortality. To survive in the blood, P aeruginosa must resist the bactericidal action of complement (ie, serum killing). Antibodies usually promote serum killing through the classical complement pathway; however, "cloaking antibodies" (cAbs) have been described, which paradoxically protect bacteria from serum killing. The relevance of cAbs in P aeruginosa BSI is unknown. METHODS: Serum and P aeruginosa were collected from a cohort of 100 patients with BSI. Isolates were tested for sensitivity to healthy control serum (HCS). cAb prevalence was determined in sera. Patient sera were mixed with HCS to determine if killing of the matched isolate was inhibited. RESULTS: Overall, 36 patients had elevated titers of cAbs, and 34 isolates were sensitive to HCS killing. Fifteen patients had cAbs and HCS-sensitive isolates; of these patients, 14 had serum that protected their matched bacteria from HCS killing. Patients with cAbs were less likely to be neutropenic or have comorbidities. CONCLUSIONS: cAbs are prevalent in patients with P aeruginosa BSI and allow survival of otherwise serum-sensitive bacteria in the bloodstream. Generation of cAbs may be a risk factor for the development of BSI.

Guideline of guidelines: management of recurrent urinary tract infections in women.

OBJECTIVE: To compare recurrent urinary tract infection (rUTI) guidelines from major urological and non-urological organisations internationally and identify areas of consensus and discrepancy. METHODS: PubMed, Google Scholar and the official webpages of major urological, gynaecological, infectious diseases and general practice organisations were searched for rUTI guidelines in March 2022. Nine guidelines were included for review: European Association of Urology, National Institute for Health and Care Excellence (NICE), Society of Obstetricians and Gynaecologists of Canada, American Academy of Family Physicians, Mexican College of Gynaecology and Obstetrics Specialists, Swiss Society of Gynaecology and Obstetrics, Spanish Society of Infectious Diseases and Clinical Microbiology, German Association of Scientific Medical Societies, and the combined American Urological Association/Canadian Urological Association/Society of Urodynamics, Female Pelvic Medicine and Urogenital Reconstruction. RESULTS: The definition and evaluation of rUTIs, and antibiotic prophylaxis strategies, were mostly consistent across guidelines, and emphasised the importance of obtaining urine cultures and limiting cystoscopy and upper tract imaging in women without risk factors. Variable recommendations were noted for symptomatic treatment, self-initiated antibiotics, and antibiotic-sparing preventative strategies such as cranberry, vaginal oestrogen, immunoactive prophylaxis with OM-89, intravesical glycosaminoglycan instillation, and phytotherapeutics. Recent randomised evidence supports the use of methenamine hippurate. Either continuous or post-coital prophylactic antibiotics were supported by all guidelines. None of the guidelines were tailored to the management recurrent complicated UTI. CONCLUSION: Multiple rUTI guidelines were identified and mostly limited their recommendations to otherwise healthy non-pregnant women with uncomplicated cystitis. Variation was noted, particularly in antibiotic-sparing preventative strategies. Some conflicting recommendations are due to more recent guidelines including updated evidence. Future guidelines should consider recommendations to assist management of complex patient groups, such as recurrent complicated UTI.

The Genomic Epidemiology of Clinical Burkholderia pseudomallei Isolates in North Queensland, Australia.

Background:Burkholderia pseudomallei, the causative agent of melioidosis, is highly genetically recombinant, resulting in significant genomic diversity. Multiple virulence factors have been associated with specific disease presentations. To date, there are limited data relating to genomic diversity and virulence factors associated with melioidosis cases in North Queensland, Australia. Aim: To describe the genetic diversity of B. pseudomallei and identify virulence factors associated with clinical risk factors and patient outcomes. Methods: Whole genome sequencing of clinical isolates was performed and analysed with clinical data obtained from a retrospective melioidosis cohort study. Results: Fifty-nine distinct sequence types (STs) were identified from the 128 clinical isolates. Six STs comprised 64/128 (50%) isolates. Novel STs accounted for 38/59 (64%) STs, with ST TSV-13 as the most prevalent (n = 7), and were less likely to possess an LPS A genotype or YLF gene cluster (p < 0.001). These isolates were most likely to be found outside the inner city (aOR: 4.0, 95% CI: 1.7-9.0, p = 0.001). ST TSV-13 was associated with increased mortality (aOR: 6.1, 95% CI: 1.2-30.9, p = 0.03). Patients with a history of alcohol excess were less likely to be infected by fhaB3 (aOR 0.2, 95% CI: 0.1-0.7, p = 0.01) or YLF (aOR: 0.4, 95% CI: 0.2-0.9, p = 0.04) positive isolates. Conclusions: There are a significant number of novel sequence types in Townsville, Australia. An emerging novel ST appears to have an association with geographic location and mortality. Ongoing investigation is required to further understand the impact of this ST on the Townsville region.

Seropositivity and geographical distribution of Strongyloides stercoralis in Australia: A study of pathology laboratory data from 2012-2016.

BACKGROUND: There are no national prevalence studies of Strongyloides stercoralis infection in Australia, although it is known to be endemic in northern Australia and is reported in high risk groups such as immigrants and returned travellers. We aimed to determine the seropositivity (number positive per 100,000 of population and percent positive of those tested) and geographical distribution of S. stercoralis by using data from pathology laboratories. METHODOLOGY: We contacted all seven Australian laboratories that undertake Strongyloides serological (ELISA antibody) testing to request de-identified data from 2012-2016 inclusive. Six responded. One provided positive data only. The number of people positive, number negative and number tested per 100,000 of population (Australian Bureau of Statistics data) were calculated including for each state/territory, each Australian Bureau of Statistics Statistical Area Level 3 (region), and each suburb/town/community/locality. The data was summarized and expressed as maps of Australia and Greater Capital Cities. PRINCIPAL FINDINGS: We obtained data for 81,777 people who underwent serological testing for Strongyloides infection, 631 of whom were from a laboratory that provided positive data only. Overall, 32 (95% CI: 31, 33) people per 100,000 of population were seropositive, ranging between 23/100,000 (95% CI: 19, 29) (Tasmania) and 489/100,000 population (95%CI: 462, 517) (Northern Territory). Positive cases were detected across all states and territories, with the highest (260-996/100,000 and 17-40% of those tested) in regions across northern Australia, north-east New South Wales and north-west South Australia. Some regions in Greater Capital Cities also had a high seropositivity (112-188/100,000 and 17-20% of those tested). Relatively more males than females tested positive. Relatively more adults than children tested positive. Children were under-represented in the data. CONCLUSIONS/SIGNIFICANCE: The study confirms that substantial numbers of S. stercoralis infections occur in Australia and provides data to inform public health planning.

Trends in Strongyloides stercoralis Faecal Larvae Detections in the Northern Territory, Australia: 2002 to 2012.

Strongyloides stercoralis is a soil-transmitted helminth (STH) endemic to tropical and subtropical areas. We reviewed the temporal detection trends in patients with S. stercoralis larvae present in faecal samples, in Northern Territory (NT) Government Health facilities, between 2002 and 2012. This was a retrospective observational study of consecutive patients with microbiologically confirmed detection of S. stercoralis in faeces. The presence of anaemia, eosinophilia, polyparasitism, and geographic and demographic data, were included in the assessment. S. stercoralis larvae were present in 389 of 22,892 faecal samples (1.7%) collected across the NT over 11 years, examined by microscopy after formol ethyl acetate concentration. 97.7% of detections were in Indigenous patients. Detections, by number, occurred in a biphasic age distribution. Detections per number of faecal samples collected, were highest in the 0⁻5 year age group. Anaemia was present in 44.8%, and eosinophilia in 49.9% of patients. Eosinophilia was present in 65.5% of the ≤5 age group, compared to 40.8% of >5 year age (p < 0.0001). Polyparasitism was present in 31.4% of patients. There was an overall downward trend in larvae detections from 2.64% to 0.99% detections/number of faecal samples year between 2002 and 2012, consistent with the trends observed for other local STHs. S. stercoralis remains an important NT-wide pathogen.