Prevalence and virulence potential of Aeromonas spp. isolated from human diarrheal samples in North East Italy

IMPORTANCE

In this work, we demonstrate the epidemiologic relevance of the Aeromonas genus as the cause of infective diarrhea in North East Italy, both in children and adult subjects, with the significative presence of highly pathogenic strains. Aeromonas strains possess a heterogeneous armamentarium of pathogenicity factors that allows the microbe to affect a wide range of human intestinal epithelial cell processes that justify the ability to induce diarrhea through different mechanisms and cause diseases of variable severity, as observed for other gastrointestinal pathogens. However, it remains to be determined whether specific genotype(s) are associated with clinical pictures of different severity to implement the diagnostic and therapeutic approaches for this relevant enteric pathogen.

Suppression of a SARS-CoV-2 outbreak in the Italian municipality of Vo'

On 21 February 2020, a resident of the municipality of Vo', a small town near Padua (Italy), died of pneumonia due to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection¹. This was the first coronavirus disease 19 (COVID-19)-related death detected in Italy since the detection of SARS-CoV-2 in the Chinese city of Wuhan, Hubei province². In response, the regional authorities imposed the lockdown of the whole municipality for 14 days³. Here we collected information on the demography, clinical presentation, hospitalization, contact network and the presence of SARS-CoV-2 infection in nasopharyngeal swabs for 85.9% and 71.5% of the population of Vo' at two consecutive time points. From the first survey, which was conducted around the time the town lockdown started, we found a prevalence of infection of 2.6% (95% confidence interval (CI): 2.1-3.3%). From the second survey, which was conducted at the end of the lockdown, we found a prevalence of 1.2% (95% CI: 0.8-1.8%). Notably, 42.5% (95% CI: 31.5-54.6%) of the confirmed SARS-CoV-2 infections detected across the two surveys were asymptomatic (that is, did not have symptoms at the time of swab testing and did not develop symptoms afterwards). The mean serial interval was 7.2 days (95% CI: 5.9-9.6). We found no statistically significant difference in the viral load of symptomatic versus asymptomatic infections (P = 0.62 and 0.74 for E and RdRp genes, respectively, exact Wilcoxon-Mann-Whitney test). This study sheds light on the frequency of asymptomatic SARS-CoV-2 infection, their infectivity (as measured by the viral load) and provides insights into its transmission dynamics and the efficacy of the implemented control measures.

Suppression of a SARS-CoV-2 outbreak in the Italian municipality of Vo'

On 21 February 2020, a resident of the municipality of Vo', a small town near Padua (Italy), died of pneumonia due to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection¹. This was the first coronavirus disease 19 (COVID-19)-related death detected in Italy since the detection of SARS-CoV-2 in the Chinese city of Wuhan, Hubei province². In response, the regional authorities imposed the lockdown of the whole municipality for 14 days³. Here we collected information on the demography, clinical presentation, hospitalization, contact network and the presence of SARS-CoV-2 infection in nasopharyngeal swabs for 85.9% and 71.5% of the population of Vo' at two consecutive time points. From the first survey, which was conducted around the time the town lockdown started, we found a prevalence of infection of 2.6% (95% confidence interval (CI): 2.1-3.3%). From the second survey, which was conducted at the end of the lockdown, we found a prevalence of 1.2% (95% CI: 0.8-1.8%). Notably, 42.5% (95% CI: 31.5-54.6%) of the confirmed SARS-CoV-2 infections detected across the two surveys were asymptomatic (that is, did not have symptoms at the time of swab testing and did not develop symptoms afterwards). The mean serial interval was 7.2 days (95% CI: 5.9-9.6). We found no statistically significant difference in the viral load of symptomatic versus asymptomatic infections (P = 0.62 and 0.74 for E and RdRp genes, respectively, exact Wilcoxon-Mann-Whitney test). This study sheds light on the frequency of asymptomatic SARS-CoV-2 infection, their infectivity (as measured by the viral load) and provides insights into its transmission dynamics and the efficacy of the implemented control measures.

Prevalence of intestinal parasitoses detected in Padua teaching hospital, Italy, March 2011 - February 2013

The aim of this study was to evaluate the distribution of parasitic intestinal infections in patients attending Padua teaching hospital during a two-year period. Between 1st March 2011 and 28th February 2013, we examined stool specimens from 7341 patients (6127 Italians, 1214 non-Italians) for ova and parasites using microscopy, rapid enzyme immunoassays, culture techniques and molecular methods. Stools of 1080 patients (14.71%) were positive for parasites; a total of 1349 intestinal parasites were counted. Protozoa were detected in 1028/1080 patients (95.19%), while helminths were present in 80/1080 patients (7.41%). The protozoa most commonly detected were Blastocystis spp., Dientamoeba fragilis and Giardia duodenalis. Enterobius vermicularis was the helminth most frequently encountered. Of the 1080 infected patients, 227 (21.02%) had more than one parasite in their stool. To conclude, in Italy intestinal parasitoses must be unquestionably considered in differential diagnoses of gastrointestinal diseases. For this purpose, sound knowledge of epidemiology is essential.

Vibrio cholerae non-O1, non-O139 bacteraemia associated with pneumonia, Italy 2016

This paper describes an elderly male patient, living in the Veneto Region, Italy, who developed Vibrio cholerae bacteraemia and pneumonia. Some days previously, while on holiday in the Lagoon of Venice, he had been collecting clams in seawater, during which he suffered small abrasions of the skin. On admission to hospital, he was confused, had fever and a cough, but neither diarrhoea nor signs of gastroenteritis were found. Both blood and stool cultures grew V. cholerae of non-O1 non-O-139 type, and the patient recovered after prompt administration of intravenous ceftriaxone for 2 weeks. This clinical case emphasises the role of global warming and climate changes in causing increasing numbers of water-borne infections.

Aeromonas spp.: an emerging pathogen?

The aim of this study is to identify and monitor the presence of <em>Aeromonas</em> spp. strains in stool cultures. We analyzed 5564 stool cultures from September 2012 to August 2013. Sixty-three patients were positive for Aeromonas spp. The most frequent symptoms were: diarrhea (46.0%) and abdominal pain (12.7%). Pediatric subjects were 28. Samples’ microscopic examination showed leukocytes in 38.1% of cases. It is still controversial whether Aeromonas are responsible for human gastroenteritis, but their presence in faecies of symptomatic patients supports their etiologic role. We propose search for toxins by polymerase chain reaction to identify strains that require an antibiotic therapy.

[Disinfection is prevention]

Prevention of outbreaks is very important in haemodialysis units because of the high risk of infectious complications caused by contaminated water or equipment. Our aim was to evaluate the efficiency of a chloride based disinfectant for haemodialysis machines. Five different machines were tested for infection by culturing water drawn from both inlet (point A) and outlet (point B) of the dialyser and from the waste site (point C). Six series of tests were analysed during a 3-week period. In the first week water was drawn from point A before and after disinfection on two different days; during the second and third weeks the same procedure was performed at points B and C, respectively. Three non-contaminated samples of 2 mL each were sent to the microbiology department for cultures. Samples from point B grew a number of bacteria even after the disinfectant for the water system was changed. We conclude that machine contamination is due to patients and, therefore, a very accurate cleaning and disinfection of system components is essential. This procedure can avoid isolation of infected patients. Prevention of infection is a complex procedure and should engage water systems, machines, as well as environment and nurses.