Nutrient concentration, loads and retention in a semiarid micro-estuary: The relative contribution of baseflow and flood events.

Estuaries are a significant source of nutrients to the marine environment. The magnitude of this source is a function of nutrients load reaching the estuary and removal (attenuation) within estuaries. Most estuarine research is conducted in large estuaries, which do not reflect the processes in small estuaries in urban and semi-arid regions where flood water is a substantial portion of the annual discharge and the estuarine baseflow is often low and dominated by wastewater. To improve the understanding of nutrient attenuation and load into the Mediterranean, we conducted high-resolution nutrient sampling in the eutrophic Alexander micro-estuary as a test case. We sampled once per month during baseflows (years 2014-2019) and hourly during floods (years 2016-2018). The concentrations of inorganic nutrients (phosphorous (P) and nitrogen (N)) were extremely high during baseflows. Dissolved ammonium and particulate P were the only nutrients that were in the estuary (by 55 % and 30 %, respectively). Floods were rare, occurring ~4 % of the time, but contributed 62 % of the annual water discharge of the Alexander micro-estuary (14.7 ± 3.8 106 m3 y-1). The concentration of all dissolved nutrients decreased during floods but was higher than expected (DIN 584 ± 50 µmol L-1, phosphate 21 ± 2 µmol L-1), accounting for 42 % and 55 % of the overall annual DIN (123.5 ± 44.9-ton yr-1) and P (6.7 ± 1.9 ton yr-1) loads to sea, respectively. The N:P ratios were 16 and 34 during baseflow and flood events, respectively. Previously, nutrient loads were calculated by multiplying baseflow-measured concentrations by the total water volume of baseflow and floods. Our calculations, based on high-resolution sampling, revealed lower annual loads of P and N to the sea that were 56 % and 89 % of previous estimates, which is a considerable difference in an oligotrophic system such as the eastern Mediterranean.

Environmental shedding of toxigenic Clostridioides difficile by asymptomatic carriers: A prospective observational study.

OBJECTIVES: The aim was to compare the burden of environmental shedding of toxigenic Clostridioides difficile among asymptomatic carriers, C. difficile-infected (CDI) patients and non-carriers in an inpatient non-epidemic setting. METHODS: C. difficile carriage was determined by positive toxin-B PCR from rectal swabs of asymptomatic patients. Active CDI was defined as a positive two-step enzyme immunoassay/polymerase chain reaction (EIA/PCR) test in patients with more than three unformed stools/24 hr. C. difficile environmental contamination was assessed by obtaining specimens from ten sites in the patients' rooms. Toxigenic strains were identified by PCR. We created a contamination scale to define the overall level of room contamination that ranged from clean to heavy contamination. RESULTS: One hundred and seventeen rooms were screened: 70 rooms inhabited by C. difficile carriers, 30 rooms by active CDI patients and 17 rooms by non C. difficile -carriers (control). In the carrier rooms 29 (41%) had more than residual contamination, from which 17 (24%) were heavily contaminated. In the CDI rooms 12 (40%) had more than residual contamination from which three (10%) were heavily contaminated, while in the control rooms, one room (6%) had more than residual contamination and none were heavily contaminated. In a multivariate analysis, the contamination score of rooms inhabited by carriers did not differ from rooms of CDI patients, yet both were significantly more contaminated than those of non-carriers odd ratio 12.23 and 11.16 (95% confidence interval 1.5-99.96 p 0.0195, and 1.19-104.49 p 0.035), respectively. DISCUSSION: Here we show that the rooms of C. difficile carriers are as contaminated as those of patients with active CDI and significantly more than those of non-carriers.

Universal screening for Clostridioides difficile in a tertiary hospital: risk factors for carriage and clinical disease.

OBJECTIVES: The role of asymptomatic carriers in Clostridioides difficile infection (CDI) epidemiology is not fully understood. Our aim was to evaluate CD carriage prevalence on admission, associated risk factors, and the risk of developing CDI. METHODS: A 10-week surveillance program for CD carriage of all medical patients admitted to the Sheba Medical Centre was implemented, utilizing an admission rectal swab PCR. Healthcare facility-onset CDI (HO-CDI) was recorded and divided into HO-CDI diagnosed in CD carriers and non-carriers. RESULTS: A total of 4601 admissions were recorded in 3803 patients; 2368 patients had technically analysable rectal swabs, of whom 81 (3.4%) were CD carriers. A multivariate logistic regression model showed that previous hospitalization, old age (>85 years) and low Norton scores were significant independent predictors of CD carriage. Carriers were more likely to receive antimicrobial therapy during hospitalization than non-carriers were. The incidence of HO-CDI in non-carriers was 4.6 cases per 10 000 patient-days; the incidence of HO-CDI in carriers was 76.7 cases per 10 000 patient-days (RR 16.6, 95% CI 4.0-69.1, p .002). CONCLUSIONS: In a prospective study, the rate of CD carriage on admission in medical patients was 3.4%. CD carriers were older, frailer, and more likely to have been hospitalized recently. HO-CDI incidence was significantly higher among CD carriers than among non-carriers, with at least a third of CDI in screened patients developing in carriers. Targeted screening of high-risk groups for CD carriage should be further considered.

The Zellweger syndrome: subcellular pathology, neuropathology, and the demonstration of pneumocystis carinii pneumonitis in two siblings.

The first Scandinavian cases of Zellweger syndrome (ZS) are described. A brother and sister, children of first cousins, had the typical clinical symptoms and pathological findings. Extensive metabolic studies in the boy were negative. Pipecolic acid in the urine was not elevated. Both children died at 14 weeks of age. Two months earlier the girl had suffered severe intestinal bleeding. Both had pneumocystic carinii pneumonia at autopsy although no evidence of immune deficiency had been found in the boy. The girl had used up her visible iron depots while the boy still had abundant but probably physiologic amounts of hemosiderin in the RES. Most of the cerebral abnormalities are unspecfic and possibly related to anoxia or other causes of delayed maturation. The white matter abnormalities in ZS patients may only be quantitatively different from the common "fatty metamorphosis" in infants. Previously reported ultrastructural abnormalities (absence of peroxisomes and very sparse smooth endoplasmic reticulum, as well as mitochondrial abnormalities) which are possibly unique for ZS, are confirmed. It is stressed that these were seen despite phenobarbital treatment which normally stimulates the formation of smooth endoplasmic reticulum.

Bee and wasp stings of the eye. Retained intralenticular wasp sting: A case report.

Two different stages should be considered in the management of bee and wasp stings to the eye. The first is the acute stage of activity of the specific insect venom on the structures the eye. The reaction of the eye to the particular insult is considered here in regard to the anterior and posterior segments of the eye. The second stage is that of the retained intraocular foreign body, the inert sting. Little is known about the reaction of the eye to the presence of chitinous sting and its effect on the structures of the eye. We report a follow-up study of a sting retained for 28 years, and emphasise the benign and quiescent course of the case. Guidelines for treatment and management in such cases are described.