The impact of COVID-19 pandemic control on vaccine-preventable invasive bacterial diseases in Piedmont (Italy).

PURPOSE: The impact of SARS-CoV-2 pandemic on other pathogens is largely unknown. We aimed to compare the prevalence of vaccine-preventable invasive bacterial infections before and during the pandemic in Piedmont (Italy). METHODS: We defined the monthly incidence of S. pneumoniae, H. influenzae and N. meningitides-invasive diseases from January 2010 to June 2021. Then, we compared the mean monthly cases during the previous 5 years (2015-2019) and the monthly cases in 2020 or 2021. RESULTS: We found significant reductions for invasive pneumococcal diseases (IPDs) in adults and H. influenzae-invasive diseases in 2020 and 2021 in comparison to the previous years, but not for invasive meningococcal diseases and IPDs in children. CONCLUSIONS: Further data are needed to confirm these findings and define possible post-pandemic evolutions in the epidemiology of vaccine-preventable invasive bacterial diseases.

Epidemiology and Impact of Anti-Pneumococcal Vaccination and COVID-19 on Resistance of Streptococcus pneumoniae Causing Invasive Disease in Piedmont, Italy.

BACKGROUND: The international surveillance of antimicrobial resistance (AMR) reports S. pneumoniae as one of leading causes of death associated with AMR. Against invasive disease, several vaccinations are available and a reduction in AMR in S. pneumoniae has been observed. Here, we evaluated the impact of anti-pneumococcal vaccination policy and the SARS-CoV2 outbreak on AMR in S. pneumoniae causing invasive disease. METHODS: We collected all strains of S. pneumoniae causing invasive disease from 2008 in the Piedmont region (Italy). Each strain was typed in order to identify the serogroup and data about AMR were collected. The population under surveillance was classified as infants, children, adults, and the old population. RESULTS: We collected n = 2076 S. pneumoniae strains, with 21.9% and 40.3% being resistant to penicillin G and erythromycin, respectively. We reported an increased risk of infection with penicillin-resistant S. pneumoniae among all populations and evaluated whether the infection was caused by a serotype included in the vaccine formulation. A similar increase was observed after the SARS-CoV2 outbreak. CONCLUSIONS: In the Piedmont region, subsequently to the introduction of anti-pneumococcal vaccination, a significant increase in the risk of penicillin G-resistant invasive pneumococcal disease among infants and old population was reported. No significant impact was found for the SARS-CoV2 outbreak.

Performance Evaluation of BD Phoenix and MicroScan WalkAway Plus for Determination of Fosfomycin Susceptibility in Enterobacterales.

BACKGROUND: Fosfomycin is an old bactericidal drug that has gained increasing interest in the last decade for its potential use in multi-drug resistant gram-negative infections. However, evidence on fosfomycin susceptibility testing reports a poor correlation between commercial methods vs. reference agar dilution (AD) for Enterobacterales (EB). The study aimed at assessing the performance of two automated systems for the determination of fosfomycin susceptibility in EB clinical isolates. METHODS: Fosfomycin susceptibility testing results of two collections of 100 non-duplicate clinical EB strains obtained using two different platforms (BD Phoenix and MicroScan WalkAway Plus) were compared with those obtained by AD. Categorical agreement (CA), major error (ME) and very major error (VME) rates were calculated. RESULTS: BD Phoenix exhibited a 6.9% rate of false-resistant results and achieved a CA of 69%, whereas MicroScan WalkAway Plus achieved 3.7% of false-resistant results and 72% of CA. Both automated systems showed poor detection of resistant isolates, with 49.1% and 56.2% of false-susceptible results for BD Phoenix and Microscan WalkAway Plus, respectively. CONCLUSIONS: Overall, agar dilution remains the most suitable method for routine laboratory antimicrobial susceptibility testing of fosfomycin on Enterobacterales strains, given the poor performance of automated systems. The application of both automated systems, in the clinical laboratories reporting of fosfomycin, should be reviewed in light of the accuracy results falling below the acceptable threshold.

Comparison of Three Different Commercial Methods for Fosfomycin Susceptibility Testing in Pseudomonas aeruginosa.

The lack of internationally approved breakpoint and a handy susceptibility testing reduces fosfomycin usefulness against Pseudomonas aeruginosa. Previous works defined low or moderate agreement between commercial methods and the reference method (agar dilution [AD]). In particular, data lack about testing against P. aeruginosa. We compared disk diffusion (DD), E-test (ET), and automated broth microdilution (BMD) to AD by testing 150 P. aeruginosa isolates. We obtained better categorical agreement (CA) for DD and ET for minimal inhibitory concentration >128 mg/L (84.7% and 92.7%, respectively), but with high very major error (VME). BMD had the lowest VME rate (2/42), but with 64% CA and 52/108 major errors. We cannot define a method comparable to AD. Larger studies, as well as the definition of a breakpoint value are needed for fosfomycin against P. aeruginosa.

Evaluation of BD Phoenix and Microscan WalkAway for determination of fosfomycin susceptibility in Staphylococcus aureus.

We evaluate the performance of BD Phoenix (BD Diagnostic; Hunt Valley, MD) and MiscroScan WalkAway (Beckman Coulter Inc; Carlsbad, CA) systems versus reference agar dilution method for fosfomycin susceptibility determination in 200 Staphylococcus aureus clinical isolates. Both methods exhibit ≤89.0% of categorica agreement and ≥63.3% of very major error. All commercial antimicrobial susceptibility systems show poor concordance with reference method.

Carbapenemase detection testing in the era of ceftazidime/avibactam-resistant KPC-producing Enterobacterales: A 2-year experience.

OBJECTIVES: The aim of this study was to investigate the prevalence of ceftazidime/avibactam (CZA) resistance among carbapenemase-producing Enterobacterales (CPE) blood culture isolates as well as the performance of the main carbapenemase phenotypic detection methods to identify KPC variants associated with CZA resistance. METHODS: Non-duplicate CPE strains isolated from blood cultures during 2018-2020 were tested for antimicrobial susceptibility. Molecular testing was used to identify carbapenemase-producers. Strains harbouring blaKPC and with a CZA minimum inhibitory concentration (MIC) ≥8 mg/L were investigated by sequencing. Subsequentially, five phenotypic carbapenemase detection methods were evaluated on these strains, namely the modified carbapenem inactivation method (mCIM), Rapidec® Carba NP, the disk diffusion synergy test, NG-Test CARBA® 5 and RESIST-5 O.O.K.N.V. RESULTS: Overall, the CZA resistance rate was high (13.7%) and remained relevant (5.9%) excluding metallo-ß-lactamases-producers. All isolates harbouringblaKPC mutants (n = 8) were associated with reduced carbapenem MICs and negative results by all detection methods based on revelation of enzyme activity. Lateral flow immunoassays failed to detect KPC-31 (n = 4) and KPC-33 (n = 2) but correctly identified KPC-14 (n = 2). Conversely, isolates harbouring wild-type KPC genes (n = 3) were associated with high-level CZA resistance and carbapenem resistance and tested positive by all of the evaluated methods. CONCLUSION: In the era of CZA-based therapies, molecular blaKPC identification followed by a carbapenem hydrolysis-based phenotypic assay could be the most reasonable diagnostic algorithm to detect all KPC-producers and to identify mutants associated with impaired carbapenemase activity and CZA resistance.

An unpleasant souvenir: Endoscopic finding of Trichuris trichiura (Nematoda: Trichuridae).

Whipworms are responsible for up to 500 million cases of trichuriasis worldwide, with higher endemicity in tropical and sub-tropical countries. In non-endemic countries, trichuriasis can be accidentally diagnosed upon colonoscopy, often in the presence of negative microscopy. Here, we describe an incidental diagnosis of trichuriasis in an HIV patient residing in a non-endemic area (i.e., Turin, Italy), six months after his return from Antigua. The species-level diagnosis was made thanks to PCR-based molecular identification of Trichuris sp. following optical microscopy detection. Overall, this case highlights the importance of improving parasitic diseases diagnosis through cutting-edge clinical and laboratory diagnostic tools alongside advanced training of specialists in the area of parasitology.