Prospective observational pilot study of the T2Resistance panel in the T2Dx system for detection of resistance genes in bacterial bloodstream infections

Early initiation of antimicrobial therapy targeting resistant bacterial pathogens causing sepsis and bloodstream infections (BSIs) is critical for a successful outcome. The T2Resistance Panel (T2R) detects the following resistance genes within organisms that commonly cause BSIs directly from patient blood samples: blaKPC, blaCTXM-14/15, blaNDM/bla/IMP/blaVIM, blaAmpC, blaOXA, vanA, vanB, and mecA/mecC. We conducted a prospective study in two major medical centers for the detection of circulating resistance genes by T2R in patients with BSIs. T2R reports were compared to antimicrobial susceptibility testing (AST), phenotypic identification, and standard molecular detection assays. Among 59 enrolled patients, 25 resistance genes were identified: blaKPC (n = 10), blaNDM/bla/IMP/blaVIM (n = 5), blaCTXM-14/15 (n = 4), blaAmpC (n = 2), and mecA/mecC (n = 4). Median time-to-positive-T2R in both hospitals was 4.4 hours [interquartile range (IQR): 3.65-4.97 hours] in comparison to that for positive blood cultures with final reporting of AST of 58.34 h (IQR: 45.51-111.2 hours; P < 0.0001). The sensitivity of T2R to detect the following genes in comparison to AST was 100% for blaCTXM-14/15, blaNDM/bla/IMP/blaVIM, blaAmpC, mecA/mecC and 87.5% for blaKPC. When monitored for the impact of significant antimicrobial changes, there were 32 events of discontinuation of unnecessary antibiotics and 17 events of escalation of antibiotics, including initiation of ceftazidime/avibactam in six patients in response to positive T2R results for blaKPC. In summary, T2R markers were highly sensitive for the detection of drug resistance genes in patients with bacterial BSIs, when compared with standard molecular resistance detection systems and phenotypic identification assays while significantly reducing by approximately 90% the time to detection of resistance compared to standard methodology and impacting clinical decisions for antimicrobial therapy.

IMPORTANCE

This is the first reported study to our knowledge to identify key bacterial resistance genes directly from the bloodstream within 3 to 5 hours in patients with bloodstream infections and sepsis. The study further demonstrated a direct effect in modifying initial empirical antibacterial therapy in response to T2R signal to treat resistant bacteria causing bloodstream infections and sepsis.

SARS-CoV-2 Infection is Associated with Age- and Gender-Specific Changes in the Nasopharyngeal Microbiome

BACKGROUND

The recent Coronavirus Disease 2019 (COVID-19) pandemic has dramatically exposed our gap in understanding the pathogenesis of airborne infections. Within such a context, it is increasingly clear that the nasal cavity represents a critical checkpoint not only in the initial colonization phase but also in shaping any infectious sequelae. This is particularly relevant to COVID-19 in that the nasal cavity is characterized by high-level expression of the Severe Acute Respiratory Syndrome CoronaVirus 2 (SARS-CoV-2) receptor, Angiotensin-Converting Enzyme 2 (ACE2), all along the respiratory tract. As part of the nasal mucosa, commensal microbes harbored by the nasal cavity likely are far more than just innocent bystanders in the interaction between SARS-CoV-2 and the local microenvironment. Yet the role of the qualitative composition of the nasal microbiome is unclear, as is its function, whether protective or not.

METHODS

In this study, individuals undergoing SARS-CoV-2 molecular testing at the Hospital of Perugia (Italy) were recruited, with their residual material from the nasopharyngeal swabs being collected for microbiome composition analysis and short-chain fatty acid (SCFA) measurements (by 16S rRNA sequencing and gas chromatography-mass spectrometry), respectively.

RESULTS

After stratification by age, gender, and viral load, the composition of the nasopharyngeal microbiome appeared to be influenced by age and gender, and SARS-CoV-2 infection further determined compositional changes. Notwithstanding this variability, a restricted analysis of female subjects-once SARS-CoV-2-infected-unraveled a shared expansion of Lachnospirales-Lachnospiraceae, irrespective of the viral load and age. This was associated with a reduction in the branched SCFA isobutanoic acid, as well as in the SCFAs with longer chains.

CONCLUSIONS

Our results indicate that the nasopharyngeal microbiome is influenced by age, gender, and viral load, with consistent patterns of microbiome changes being present across specific groups. This may help in designing a personalized medicine approach in COVID-19 patients with specific patterns of nasal microbial communities.

Impaired neutralizing antibody efficacy of tixagevimab-cilgavimab 150+150 mg as pre-exposure prophylaxis against Omicron BA.5. A real-world experience in booster vaccinated immunocompromised patients

BACKGROUND

Tixagevimab-cilgavimab has been approved as primary pre-exposure prophylaxis in immunocompromised patients as support or replacement for vaccination, even though the Omicron variant of concern (VOC) was spreading at the time.

OBJECTIVES

The aim of our study was to evaluate the post-injection neutralising activity (NT90-Abs titre) against the Omicron BA.5 variant in fully vaccinated immunocompromised patients.

STUDY DESIGN

NT90-Abs titres against BA.5 and 20A.EU1 as well as anti-spike and anti-receptor-binding domain IgG were evaluated 0, 14, and 30 d after tixagevimab-cilgavimab administration. The primary end point was NT90-Abs titres ≥ 80 against BA.5 in ≥ 25% of patients, and the secondary end point was NT90-Abs titres ≥ 1280 against 20A.EU1 in >50% of patients on day 14.

RESULTS

At baseline, 35.2%, 37.02%, and 32.5% of booster vaccinated patients exhibited undetectable levels of anti-S and anti-RBD IgG antibodies such as NT90-Abs titres against A20.EU1. Moreover, 35 patients (61.5%) had undetectable NT90-Abs titres against BA.5. On day 14, IgG anti-S and anti-RBD levels were 3880 BAU/mL and 776.6 AU/mL, respectively. Only 12.5% of patients met a NT90-Abs titres ≥ 80 against BA.5, whereas the median NT90-Abs titre against 20A.EU1 was 1280. NT90-Abs titres against BA.5 were 64-fold lower than those against A20.EU1. Four patients (7.5%) had a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in the 3 months after treatment, all with a time gap between the booster vaccination and injection.

CONCLUSIONS

To date, tixagevimab-cilgavimab cannot be considered a substitute for vaccination but may be a useful supporting therapy if the recommended dose for pre-exposure prophylaxis is doubled.

Laboratory automation, informatics, and artificial intelligence: current and future perspectives in clinical microbiology

Clinical diagnostic laboratories produce one product-information-and for this to be valuable, the information must be clinically relevant, accurate, and timely. Although diagnostic information can clearly improve patient outcomes and decrease healthcare costs, technological challenges and laboratory workflow practices affect the timeliness and clinical value of diagnostics. This article will examine how prioritizing laboratory practices in a patient-oriented approach can be used to optimize technology advances for improved patient care.

Differences in the Expression Levels of SARS-CoV-2 Spike Protein in Cells Treated with mRNA-Based COVID-19 Vaccines: A Study on Vaccines from the Real World

Comirnaty (BNT162b2) and Spikevax (mRNA-1273) COVID-19 vaccines encode a full-length SARS-CoV-2 Spike (S) protein. To evaluate whether the S-protein expressed following treatment with the two vaccines differs in the real-world context, two cell lines were treated for 24 h with two concentrations of each vaccine, and the expression of the S-protein was evaluated using flow cytometry and ELISA. Vaccines were obtained from three vaccination centers in Perugia (Italy) that provided us with residual vaccines present in vials after administration. Interestingly, the S-protein was detected not only on the cell membrane but also in the supernatant. The expression was dose-dependent only in Spikevax-treated cells. Furthermore, the S-protein expression levels in both cells and supernatant were much higher in Spikewax-than in Comirnaty-treated cells. Differences in S-protein expression levels following vaccine treatment may be attributed to variations in the efficacy of lipid nanoparticles, differences in mRNA translation rates and/or loss of some lipid nanoparticles' properties and mRNA integrity during transport, storage, or dilution, and may contribute to explaining the slight differences in the efficacy and safety observed between the Comirnaty and Spikevax vaccines.

In vivo evolution to echinocandin resistance and increasing clonal heterogeneity in Candida auris during a difficult-to-control hospital outbreak, Italy, 2019 to 2022

A difficult-to-control outbreak of Candida auris is ongoing in a large tertiary care hospital in Liguria, Italy, where it first emerged in 2019. In a retrospective analysis, 503 cases of C. auris carriage or infection were observed between July 2019 and December 2022. Genomic surveillance identified putative cases that no longer occurred as part of one defined outbreak and the emergence of echinocandin (pandrug) resistance following independent selection of FKS1S639F and FKS1F635Y mutants upon prolonged exposure to caspofungin and/or anidulafungin.

COVID-19 infection-associated platelet and neutrophil activation is blunted by previous anti-SARS-CoV-2 vaccination

The effectiveness of vaccination against SARS-CoV-2 in preventing COVID-19 or in reducing severe illness in subjects hospitalized for COVID-19 despite vaccination has been unequivocally shown. However, no studies so far have assessed if subjects who get COVID-19 despite vaccination are protected from SARS-CoV-2-induced platelet, neutrophil and endothelial activation, biomarkers associated with thrombosis and worse outcome. In this pilot study, we show that previous vaccination blunts COVID-19-associated platelet activation, assessed by circulating platelet-derived microvesicles and soluble P-selectin, and neutrophil activation, assessed by circulating neutrophil extracellular trap (NET) biomarkers and matrix metalloproteinase-9, and reduces COVID-19-associated thrombotic events, hospitalization in intensive-care units and death.

Seven Years of Culture Collection of Neisseria gonorrhoeae: Antimicrobial Resistance and Molecular Epidemiology

The emergence of Neisseria gonorrhoeae isolates displaying resistance to antimicrobials, in particular to ceftriaxone monotherapy or ceftriaxone plus azithromycin, represents a global public health concern. This study aimed to analyze the trend of antimicrobial resistance in a 7-year isolate collection retrospective analysis in Italy. Molecular typing on a subsample of gonococci was also included. A total of 1,810 culture-positive gonorrhea cases, collected from 2013 to 2019, were investigated by antimicrobial susceptibility, using gradient diffusion method, and by the N. gonorrhoeae multiantigen sequence typing (NG-MAST). The majority of infections occurred among men with urogenital infections and 57.9% of male patients were men who have sex with men. Overall, the cefixime resistance remained stable during the time. An increase of azithromycin resistance was observed until 2018 (26.5%) with a slight decrease in the last year. In 2019, gonococci showing azithromycin minimum inhibitory concentration above the EUCAST epidemiological cutoff value (ECOFF) accounted for 9.9%. Ciprofloxacin resistance and penicillinase-producing N. gonorrhoeae (PPNG) percentages increased reaching 79.1% and 18.7% in 2019, respectively. The most common sequence types identified were 5,441, 1,407, 6,360, and 5,624. The predominant genogroup (G) was the 1,407; moreover, a new genogroup G13070 was also detected. A variation in the antimicrobial resistance rates and high genetic variability were observed in this study. The main phenotypic and genotypic characteristics of N. gonorrhoeae isolates were described to monitor the spread of drug-resistant gonorrhea.

Monitoring of indoor bioaerosol for the detection of SARS-CoV-2 in different hospital settings

Background

Spore Trap is an environmental detection technology, already used in the field of allergology to monitor the presence and composition of potentially inspirable airborne micronic bioparticulate. This device is potentially suitable for environmental monitoring of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) in hospital, as well as in other high-risk closed environments. The aim of the present study is to investigate the accuracy of the Spore Trap system in detecting SARS-CoV-2 in indoor bioaerosol of hospital rooms.

Methods

The Spore Trap was placed in hospital rooms hosting patients with documented SARS-CoV-2 infection (n = 36) or, as a negative control, in rooms where patients with documented negativity to a Real-Time Polymerase Chain Reaction molecular test for SARS-CoV-2 were admitted (n = 10). The monitoring of the bioaerosol was carried on for 24 h. Collected samples were analyzed by real-time polymerase chain reaction.

Results

The estimated sensitivity of the Spore Trap device for detecting SARS-CoV-2 in an indoor environment is 69.4% (95% C.I. 54.3-84.4%), with a specificity of 100%.

Conclusion

The Spore Trap technology is effective in detecting airborne SARS-CoV-2 virus with excellent specificity and high sensitivity, when compared to previous reports. The SARS-CoV-2 pandemic scenario has suggested that indoor air quality control will be a priority in future public health management and will certainly need to include an environmental bio-investigation protocol.

Immune correlates of protection by vaccine against SARS-CoV-2 in patients with chronic lymphocytic leukaemia

In chronic lymphocytic leukaemia (CLL) the efficacy of SARS-CoV-2 vaccination remains unclear as most studies have focused on humoral responses. Here we comprehensively examined humoral and cellular responses to vaccine in CLL patients. Seroconversion was observed in 55.2% of CLL with lower rate and antibody titres in treated patients. T-cell responses were detected in a significant fraction of patients. CD4⁺ and CD8⁺ frequencies were significantly increased independent of serology with higher levels of CD4⁺ cells in patients under a Bruton tyrosine kinase (BTK) or a B-cell lymphoma 2 (BCL-2) inhibitor. Vaccination skewed CD8⁺ cells towards a highly cytotoxic phenotype, more pronounced in seroconverted patients. A high proportion of patients showed spike-specific CD4⁺ and CD8⁺ cells producing interferon gamma (IFNγ) and tumour necrosis factor alpha (TNFα). Patients under a BTK inhibitor showed increased production of IFNγ and TNFα by CD4⁺ cells. Vaccination induced a Th1 polarization reverting the Th2 CLL T-cell profile in the majority of patients with lower IL-4 production in untreated and BTK-inhibitor-treated patients. Such robust T-cell responses may have contributed to remarkable protection against hospitalization and death in a cohort of 540 patients. Combining T-cell metrics with seroprevalence may yield a more accurate measure of population immunity in CLL, providing consequential insights for public health.

Prosthetic joint infection diagnosis applying the three-level European Bone and Joint Infection Society (EBJIS) approach

Sensitive and specific tests for the diagnosis of prosthetic joint infection (PJI) are lacking. The aim of this study was to report clinical and microbiological findings of consecutive patients diagnosed with PJI at the University Hospital of Perugia, Perugia, Italy, and to validate these diagnoses utilizing the European Bone and Joint Infection Society (EBJIS) three-level diagnostic approach from 2021. Patients with a PJI diagnosis were included in this study and examined retrospectively. Overall, 133 patients were diagnosed with PJI: mean age 72 years, 54.9% female, and 55.6% with more than one comorbidity. The most frequent involved joints were hip 47% and knee 42%. Aetiology was identified in 88/133 (66.2%): staphylococci resulted the most frequent microorganisms and over 80% (45/54) resulted rifampin susceptible. Applying the EBJIS approach, PJI diagnosis resulted: confirmed in 101 (75.9%), likely in 25 (18.8%), and unlikely in 7 (5.3%). Likely PJIs aetiology was Staphylococcus aureus 11/25, coagulase-negative staphylococci 8/25, Streptococcus agalactiae 3/25, viridans group streptococci 2/25, and Pseudomonas aeruginosa 1/25. No statistically significant differences were detected among the three diagnosis groups with regard to clinical characteristics with the exception of a higher number of confirmed PJIs occurring < 3 months after implantation. The logistic regression analysis did not disclose any independent predictor of confirmed PJIs. We recommend using all the diagnostic tests available to approach PJI diagnosis, and suggest caution before rejecting PJI diagnosis in the presence of highly virulent microorganisms from a single sample, in patients without sinus tract, and in those receiving antimicrobial at the time microbiologic samples are collected. Study approved by Umbrian Regional Ethical Committee, Perugia, Italy, Prot. N. 23,124/21/ON of 10.27.2021.

Effect of a UV-C Automatic Last-Generation Mobile Robotic System on Multi-Drug Resistant Pathogens

Background: Healthcare-associated infections caused by multi-drug resistant (MDR) pathogens are associated with increased mortality and morbidity among hospitalized patients. Inanimate surfaces, and in particular high-touch surfaces, have often been described as the source for outbreaks of nosocomial infections. The present work aimed to evaluate the efficacy of a last-generation mobile (robotic) irradiation UV-C light device R2S on MDR microorganisms in inanimate surfaces and its translation to hospital disinfection. Methods: The efficacy of R2S system was evaluated in environmental high-touch surfaces of two separate outpatient rooms of Perugia Hospital in Italy. The static UV-C irradiation effect was investigated on both the bacterial growth of S. aureus, MRSA, P. aeruginosa, and K. pneumoniae KPC and photoreactivation. The antimicrobial activity was also tested on different surfaces, including glass, steel, and plastic. Results: In the environmental tests, the R2S system decreased the number of bacteria, molds, and yeasts of each high-touch spot surface (HTSs) compared with manual sanitization. UV-C light irradiation significantly inhibits in vitro bacterial growth, also preventing photoreactivation. UV-C light bactericidal activity on MDR microorganisms is affected by the type of materials of inanimate surfaces. Conclusions: The last-generation mobile R2S system is a more reliable sanitizing procedure compared with its manual counterpart.

Role of Nucleocapsid Protein Antigen Detection for Safe End of Isolation of SARS-CoV-2 Infected Patients with Long Persistence of Viral RNA in Respiratory Samples

Background. In SARS-CoV-2 infection, viral RNA may persist in respiratory samples for several weeks after the resolution of symptoms. Criteria to assess the end of infectivity are not unequivocally defined. In some countries, time from diagnosis is the unique criterion used, in addition to symptom cessation. This study evaluates the role of the Lumipulse^® Antigen Assay (LAA) for the safe end of isolation of patients ≥21 days after the diagnosis of infection. Methods. A total of 671 nasopharyngeal swabs from patients diagnosed with infection at least 21 days before were assessed by RT-PCR and LAA, and the role of LAA in predicting the absence of infectivity was evaluated by virus cell culture. Results. Viable virus was present in 10/138 cultured samples. Eight out of ten infective patients suffered from a concomitant disease, predisposing them to long-term shedding of infective virus. In particular, infectious virus was isolated from 10/20 RT-PCR+/LAA+ cultured samples, whereas no viable virus was found in all 118 RT-PCR+/LAA– cultured swabs. LLA and RT-PCR agreed in 484/671 (72.1%) samples, with 100% and 26.7% concordance in RT-PCR negative and positive samples, respectively. Conclusions. Viable virus can be found ≥21 days after diagnosis in immunocompromised or severely ill patients. LAA better than RT-PCR predicts non-infectivity of patients and can be safely used to end isolation in cases with long persistence of viral RNA in the respiratory tract.

Accuracy and Impact on Patient Management of New Tools for Diagnosis of Sepsis: Experience with the T2 Magnetic Resonance Bacteria Panel

The rapid and accurate identification of pathogens responsible for sepsis is essential for prompt and effective antimicrobial therapy. Molecular technologies have been developed to detect the most common causative agents, with high sensitivity and short time to result (TTR). T2 Bacteria Panel (T2), based on a combination of PCR and T2 magnetic resonance, can identify directly in blood samples Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae, Pseudomonas aeruginosa, Enterococcus faecium, and Acinetobacter baumannii pathogens. This study evaluates the role of T2 in the diagnosis of sepsis and its impact on patient management, specifically in terms of TTR and the switch from empirical to directed therapy, comparing results of blood culture (BC) and T2 assay in 82 patients with sepsis. T2 significantly improved the detection of the causative agents of sepsis. For pathogens included in the panel, T2 sensitivity was 100% (95% CI 86.3–100.0), significantly higher than that of BC (54.8%, 95% CI 36.0–72.7). The TTR (median, IQR) of positive T2 (3.66 h, 3.59–4.31) was significantly shorter than that of the positive BC (37.58 h, 20.10–47.32). A significant reduction in the duration of empiric therapy and an increase in the percentage of patients with switched therapy was observed in patients with a positive T2 result. In conclusion, T2 can shorten and improve the etiological diagnosis of sepsis with a positive impact on patient management.

Evaluation of Lumipulse® G SARS-CoV-2 antigen assay automated test for detecting SARS-CoV-2 nucleocapsid protein (NP) in nasopharyngeal swabs for community and population screening

Objectives

To compare the Lumipulse® SARS-CoV-2 antigen test with the gold standard real-time reverse transcription-polymerase chain reaction (RT-PCR) for diagnosis of SARS-CoV-2 infection and to evaluate its role in screening programs.

Methods

Lumipulse® SARS-CoV-2 antigen assay was compared with the gold standard RT-PCR test in a selected cohort of 226 subjects with suspected SARS-CoV-2 infection, and its accuracy was evaluated. Subsequently, the test was administered to a real-life screening cohort of 1738 cases. ROC analysis was performed to explore test features and cutoffs. All tests were performed in the regional reference laboratory in Umbria, Italy.

Results

A 42.0% positive result at RT-PCR was observed in the selected cohort. The Lumipulse® system showed 92.6% sensitivity (95% CI 85.4–97.0%) and 90.8% specificity (95% CI 84.5–95.2%) at 1.24 pg/mL optimal cutoff. In the screening cohort, characterized by 5.2% prevalence of infection, Lumipulse® assay showed 100% sensitivity (95% CI 96.0–100.0%) and 94.8% specificity (95% CI 93.6–95.8%) at 1.645 pg/mL optimal cutoff; the AUC was 97.4%, NPV was 100% (95% CI 99.8–100.0%) and PPV was 51.1% (95% CI 43.5–58.7%).

Conclusions

The Lumipulse® SARS-CoV-2 antigen assay can be safely employed in the screening strategies in small and large communities and in the general population.

Is recurrence possible in coronavirus disease 2019 (COVID-19)? Case series and systematic review of literature

Can a patient diagnosed with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) be infected again? This question is still unsolved. We tried to analyze local and literature cases with a positive respiratory swab after recovery. We collected data from symptomatic patients diagnosed with SARS-CoV-2 infection in the Italian Umbria Region that, after recovery, were again positive for SARS-CoV-2 in respiratory tract specimens. Samples were also assessed for infectivity in vitro. A systematic review of similar cases reported in the literature was performed. The study population was composed of 9 patients during a 4-month study period. Among the new positive samples, six were inoculated in Vero-E6 cells and showed no growth and negative molecular test in culture supernatants. All patients were positive for IgG against SARS-CoV-2 nucleoprotein and/or S protein. Conducting a review of the literature, 1350 similar cases have been found. The presumptive reactivation occurred in 34.5 days on average (standard deviation, SD, 18.7 days) after COVID-19 onset, when the 5.6% of patients presented fever and the 27.6% symptoms. The outcome was favorable in 96.7% of patients, while the 1.1% of them were still hospitalized at the time of data collection and the 2.1% died. Several hypotheses have been formulated to explain new positive respiratory samples after confirmed negativity. According to this study, the phenomenon seems to be due to the prolonged detection of SARS-CoV-2 RNA traces in respiratory samples of recovered patients. The failure of the virus to replicate in vitro suggests its inability to replicate in vivo.

Search for SARS-CoV-2 RNA in platelets from COVID-19 patients

The frequent finding of thrombocytopenia in patients with severe SARS-CoV-2 infection (COVID-19) and previous evidence that several viruses enter platelets suggest that SARS-CoV-2 might be internalized by platelets of COVID-19. Aim of our study was to assess the presence of SARS-CoV-2 RNA in platelets from hospitalized patients with aconfirmed diagnosis of COVID-19. RNA was extracted from platelets, leukocytes and serum from 24 COVID-19 patients and 3 healthy controls, real-time PCR and ddPCR for viral genes were carried out. SARS-CoV-2 RNA was not detected in any of the samples analyzed nor in healthy controls, by either RT-PCR or ddPCR, while RNA samples from nasopharyngeal swabs of COVID-19 patients were correctly identified. Viral RNA was not detected independently of viral load, of positive nasopharyngeal swabs, or viremia, the last detected in only one patient (4.1%). SARS-CoV-2 entry in platelets is not acommon phenomenon in COVID-19 patients, differently from other viral infections.

Accelerate Pheno™ blood culture detection system: a literature review

Accelerate Pheno™ (ACC) is a fully automated system providing rapid identification of a panel of bacteria and yeasts, and antimicrobial susceptibility testing of common bacterial pathogens responsible for bloodstream infections and sepsis. Diagnostic accuracy for identification ranges from 87.9 to 100%, and antimicrobial susceptibility testing categorical agreement is higher than 91%. The present review includes peer-reviewed studies on ACC published to date. Both interventional and hypothetical studies evidenced the potential positive clinical role of ACC in the management and therapy of patients with bloodstream infections and sepsis, due to the important reduction in time to report, suggesting a crucial impact on the therapeutic management of these patients, provided the presence of a hospital antimicrobial stewardship program, a 24/7 laboratory operating time and a strict collaboration between clinical microbiologist and clinician. Further prospective multicenter studies are necessary to explore the impact of this system on mortality, length of stay and spread of multidrug-resistant organisms.

Trends in the Incidence and Antibiotic Resistance of Enterococcal Bloodstream Isolates: A 7-Year Retrospective Multicenter Epidemiological Study in Italy

The spread of resistance to vancomycin and other last-resort drugs in Enterococcus spp. remains of concern. In Italy, surveillance data for enterococcal bloodstream isolates in humans are scant. The aim of our study was to assess the incidence trends of bacteremias due to Enterococcus species and their prevalence trends of antimicrobial resistance. We retrospectively included all consecutive not-duplicate Enterococcus species isolated from blood cultures, in patients from 11 Italian hospitals (2011-2017). Incidence was defined as the number of isolates per 10,000 patient-days, while resistance prevalence was defined as the number of resistant strains divided by the number of tested strains. We included 4,858 isolates (59%, 36%, and 5% due to Enterococcus faecalis, E. faecium, and other Enterococcus spp., respectively). Over the study period, the incidence of bacteremias due to E. faecalis (incidence rate ratio [IRR]: 1.02, 95% confidence interval [CI]: 1.00-1.04, p = 0.008) and E. faecium increased (IRR: 1.03, 95% CI: 1.01-1.05, p < 0.001) alongside with the whole enterococcal bacteremias trend (IRR: 1.02, 95% CIs: 1.01-1.04, p = 0.002). A progressive increase in vancomycin-resistant E. faecium (VREfm) bacteremias was observed. Resistance to tigecycline and linezolid was rarely reported. The incidence of enterococcal bloodstream isolates is increasing in Italy, together with the prevalence of VREfm. Resistance to linezolid, a cornerstone drug used in the treatment of VRE bloodstream infection, remains negligible.

In vitro antibacterial activity of ceftazidime/avibactam in combination against planktonic and biofilm carbapenemase-producing Klebsiella pneumoniae isolated from blood

OBJECTIVES

The aim of this study was to report on in vitro tests of antibacterial activity of ceftazidime/avibactam in combination against planktonic or biofilm KPC carbapenemase-producing Klebsiella pneumoniae (KPC-Kp), the rate of KPC-Kp blood isolates in University of Perugia Hospital over a 5-year period, and their antimicrobial susceptibility patterns.

METHODS

The antibacterial activity of ceftazidime/avibactam in combination with other antimicrobials was assessed against planktonic and biofilm bacteria by Etest and checkerboard assay. A retrospective review of laboratory data was performed to evaluate the rate of KPC-Kp from blood samples and their antimicrobial susceptibility patterns.

RESULTS

Between 2014 and 2019, 130/4241 (3.1%) KPC-Kp were identified from blood cultures. Their rate increased from 2.3% in 2014-2015 to 4.5% over the last 3 years. Overall, 4.6% (6/130) of KPC-Kp isolates were susceptible to meropenem, 65.4% (85/130) to colistin, 65.1% (84/129) to tigecycline, 34.6% (45/130) to amikacin, 36.2% (42/116) to gentamicin, 40.2% (39/97) to fosfomycin and 91.5% (65/71) to ceftazidime/avibactam. Five of six ceftazidime/avibactam-resistant KPC-Kp were isolated from patients not treated with ceftazidime/avibactam. Synergism was detected both by Etest and checkerboard assay for the combination of ceftazidime/avibactam plus meropenem against planktonic isolates, whilst lower bactericidal activity was observed in biofilm KPC-Kp isolates.

CONCLUSIONS

Our in vitro data suggest that the combination of ceftazidime/avibactam plus meropenem has a synergistic antibacterial activity against planktonic bacteria, whilst a lower activity was detected against biofilm, suggesting worse clinical outcomes whenever biofilm infections are present. Further analyses are required to confirm these results before extending them to clinical practice.

Measles immunity in healthcare workers of an Italian hospital

BACKGROUND

In Italy, 4991 cases of measles were reported in 2017 and 322 involved healthcare workers (HCWs). These professionals are at high risk of infection and transmission of virus both to other hospital staff and importantly, to patients, some of whom may be at risk of severe illness and complications. According to the Italian National Immunization and Prevention Plan, all HCWs should have demonstrable evidence of immunity to measles and specific hospital surveillance is recommended. Given a recent measles outbreak recorded in Italy, which also involved HCWs, the aim of this study has been to assess the measles immunization status of the Perugia General Hospital's HCWs.

METHODS

A survey on all hospital staff was carried out, using a questionnaire to obtain information on demographic characteristics, personal history of measles and self-reported vaccination status, and offering the serological testing to HCWs who did not know their immune status.

RESULTS

Among the 1714 HCWs included in the study, 1207 (70%) were protected against measles (due to vaccination or natural infection), and 507 (30%) did not know their immune status. Of these, 461 subjects accepted a serological control, while 46 refused. Protective measles-specific IgG antibody titres were documented in 410/461 (89%) HCWs, and the percentage of immune subjects decreased with the age.

CONCLUSIONS

Our study shows that in Perugia General Hospital, 26% of HCWs under the age of 30 were not protected against measles. In Italy, campaigns promoting vaccination of HCWs are needed to prevent transmission of this infection in hospital setting.

Cocirculation of Hajj and non-Hajj strains among serogroup W meningococci in Italy, 2000 to 2016

In Italy, B and C are the predominant serogroups among meningococci causing invasive diseases. Nevertheless, in the period from 2013 to 2016, an increase in serogroup W Neisseria meningitidis (MenW) was observed. This study intends to define the main characteristics of 63 MenW isolates responsible of invasive meningococcal disease (IMD) in Italy from 2000 to 2016. We performed whole genome sequencing on bacterial isolates or single gene sequencing on culture-negative samples to evaluate molecular heterogeneity. Our main finding was the cocirculation of the Hajj and the South American sublineages belonging to MenW/clonal complex (cc)11, which gradually surpassed the MenW/cc22 in Italy. All MenW/cc11 isolates were fully susceptible to cefotaxime, ceftriaxone, ciprofloxacin, penicillin G and rifampicin. We identified the full-length NadA protein variant 2/3, present in all the MenW/cc11. We also identified the fHbp variant 1, which we found exclusively in the MenW/cc11/Hajj sublineage. Concern about the epidemic potential of MenW/cc11 has increased worldwide since the year 2000. Continued surveillance, supported by genomic characterisation, allows high-resolution tracking of pathogen dissemination and the detection of epidemic-associated strains.

The role of ozonized oil and a combination of tobramycin/dexamethasone eye drops in the treatment of viral conjunctivitis: a randomized clinical trial

Purpose

To determine whether topical tobramycin 0.3%/dexamethasone 0.1% plus ozonized oil eye drops reduces clinical signs and infectious viral titers of presumed viral conjunctivitis more than tobramycin/dexamethasone eye drops alone.

Methods

Prospective, single-blind, randomized, parallel-groups trial. Eighty patients with a clinical diagnosis of presumed viral conjunctivitis were randomizedly divided into two treatment groups: a study group and a control group, 40 for each group. Patients in the study group received topical tobramycin 0.3%/dexamethasone 0.1% eye drops, plus ozonized oil eye drops, both four times daily; patients in the control group received only topical tobramycin 0.3%/dexamethasone eye drops four times daily. The treatment was for seven days in both groups. Swabs were taken from the conjunctival fornix for adenovirus PCR analysis on the day of recruitment and at seven days follow-up. Clinical signs were also recorded on the day of recruitment and at follow-up examination: the main outcomes were conjunctival injection and conjunctival chemosis, graded on a 4-point clinical scale, presence or absence of superficial punctate keratitis and subepithelial corneal infiltrates.

Results

No statistically significant difference was reached in adenoviral infection negativization between the two groups, although the study group showed a higher number of PCR negative results at seven days follow-up. PCR real time detected adenoviral infection in 17 of 24 patients on the day of recruitment and it was positive in 4 patients on the seventh day (viral positivity reduction of 76%). In the control group PCR was positive for adenovirus in 18 of 24 patients on the day of recruitment and in 7 patients at seven days follow-up (reduction of 61%). There was statistically significant difference on conjunctival clinical signs between the study and control groups. Significant difference was also found on superficial punctate keratitis resolution between the study and the control group. In the former superficial punctate keratitis was detected in 14 eyes on the first day and in 5 eyes after seven days while in the latter superficial punctate keratitis was found in 124 eyes on the first day and in 6 eyes on the seventh day. No difference was found in subepithelial corneal infiltrates appearance between the two groups.

Conclusions

The use of ozonized-oil containing eye drops in combination with topical tobramycin 0.3%/dexamethasone 0.1% eye drops four times daily seems to reduce the signs of conjunctivitis, and the duration of viral infection, although it does not affect the subepithelial corneal infiltrates appearance.

Frequency and clinical correlates of antiphospholipid antibodies arising in patients with SARS-CoV-2 infection: findings from a multicentre study on 122 cases

OBJECTIVES

COVID-19 features include disseminated intravascular coagulation and thrombotic microangiopathy indicating a hypercoagulable state. We aimed to investigate antiphospholipid antibodies (aPL) prevalence and clinical relationships in a large cohort of COVID-19 patients.

METHODS

We analysed the prevalence and titres of serum aPL in 122 patients with COVID-19 and 157 with primary antiphospholipid syndrome (PAPS) and 91 with other autoimmune rheumatic diseases (oARD) for comparison. IgG/IgM anticardiolipin (aCL) and IgG/IgM anti-beta2glycoprotein I (β2GPI) were assayed using homemade ELISA, IgA aCL and anti-β2GPI by commercial ELISA kits and lupus anticoagulant (LAC) by multiple coagulation tests following updated international guidelines.

RESULTS

Prevalence of IgG and IgM aCL and of IgG and IgM anti-β2GPI across COVID-19 patients were 13.4%, 2.7%, 6.3% and 7.1%, being significantly lower than in PAPS (p<0.0001 for all). Frequency of IgG aCL and IgM anti-β2GPI was comparable to oARD (13.4% vs. 13.2% and 7.1% vs. 11%, respectively), while IgG anti-β2GPI and IgM aCL were lower (p<0.01). IgA aCL and IgA anti-β2GPI were retrieved in 1.7% and 3.3% of COVID-19 patients, respectively. Positive LAC was observed in 22.2% COVID-19 vs. 54.1% of PAPS (p<0.0001) and 14.6% of oARD (p=0.21). Venous or arterial thromboses occurred in 18/46 (39.1%) COVID-19 patients and were not associated with positive aPL (p=0.09).

CONCLUSIONS

Thrombosis is a frequent manifestation during COVID-19 infection. However, prevalence and titres of aPL antibodies or LAC were neither consistently increased nor associated with thrombosis when measured at a single timepoint, therefore not representing a suitable screening tool in the acute stage of disease.

Improving the etiological diagnosis of osteoarticular infections with the commercial multiplex real-time polymerase chain reaction SeptiFast®

Detection of etiological agents is pivotal for adequate therapy of osteoarticular bacterial infections. Culture often lacks sensitivity, especially in patients under antibiotic therapy. The present study investigates the potential clinical utility of the commercial multiplex real-time polymerase chain reaction SeptiFast® (SF) in the etiological diagnosis of osteoarticular infections. Results obtained from conventional culture and SF were compared in 86 osteoarticular specimens collected from patients with suspected infection. The number of specimens positive by SF (38/86, 44.18%) was significantly greater (P = 0.001) than that of specimens positive by culture (20/86, 23.25%). The sensitivity of SF was 48.71%, significantly higher than culture sensitivity (25.64%). Specificity was 100% for both tests. The overall diagnostic accuracy for SF was 53.48%, and that of culture was 32.55%. Even with the limitation of the low number of specimens, this study supports the usefulness of SF in the diagnosis of osteoarticular infections.

Accelerate Pheno™ system in sepsis by Gram-negative pathogens: four months of hospital experience

This study reports our experience with the Accelerate PhenoTM system (ACC) to guide management of patients with sepsis by Gram-negative pathogens. A diagnostic workflow, based on pathogen and resistance genes detection or ACC testing, was applied to 33 patients. Clinical and microbiological data were recorded, and analysis of broad-spectrum agents sparing was performed. Antimicrobial susceptibility results by ACC were available for 28 of 33 patients (84.85%). Among 434 microorganism-antimicrobial combinations, categorical agreement was 97.93%, very major errors 0.23%, major errors 1.15%, and minor errors 0.69%. Time to report (mean ± SD) of ACC results was 27.14±6.90 h from sample collection, significantly shorter (p<0.001, Δ = 19.96 h, 95% CI: 24.71-15.22) than that of the standard method (47.10±11.92 h). A switch from empiric to targeted therapy was observed in 14 of 28 patients (50.0%), duration of empiric therapy was 37.73±19.87 h, with a saving of 5.45 piperacillin/tazobactam and 5.28 carbapenems prescribed daily doses. Considering patients in which de-escalation would have been theoretically feasible, 27.69 prescribed daily doses of piperacillin/tazobactam and 19.08 of carbapenems could had been spared, compared to standard methods. In conclusion, ACC could impact positively on the management of septic patients by Gram-negative pathogens.

655. Detection of Antibiotic Resistance Genes in Clinical Samples using T2 Magnetic Resonance

Background

Antibiotic-resistant bacteria are spread through selective pressure from the use of broad-spectrum empirical therapies, mobile genetic elements that pass resistance genes between species, and the inability to rapidly and appropriately respond to their presence. Resistance gene identification is often performed with post culture molecular diagnostic tests. The T2Resistance Panel, which detects methicillin resistance genes mecA/C; vancomycin resistance genes vanA/B; carbapenemases bla_KPC, bla_OXA-48,bla_NDM, bla_VIM, and bla_IMP; AmpC β-lactamases bla_CMY and bla_DHA; and extended-spectrum β-lactamases bla_CTX-M directly from patient blood samples, is based on T2 magnetic resonance (T2MR), an FDA-cleared technology with demonstrated high sensitivity and specificity for culture-independent bacterial and fungal species identification. Here we report the clinical performance of T2MR detection of resistance genes directly from patient blood samples.

Methods

Patients with a clinical diagnosis of sepsis and an order for blood culture (BC) were enrolled in the study at two sites. BCs were managed using standard procedures and MALDI-TOF for species identification. Resistance testing with the T2MR assay was performed on a direct patient draw and compared with diagnostic test results from concurrent BC specimen and BC specimen taken at other points in time. The potential impact on therapy was evaluated through patient chart review.

Results

T2MR detected the same resistance genes as detected by post culture diagnostics in 100% of samples from concurrent blood draws. Discordant results occurred when T2MR was taken ≥48 hours after BC for patients on antimicrobial therapy. The average time to positive result was 5.9 hours with T2MR vs. 30.6 hours with post-culture molecular testing.

Conclusion

The T2Resistance Panel detected antibiotic resistance genes in clinical samples and displayed agreement with post culture genetic testing. T2MR results were achieved faster than culture-dependent diagnostic testing results and may allow for an earlier change from empiric to directed therapy. The use of culture-independent diagnostics like T2MR could enable a quicker response to antibiotic-resistant organisms for individual patients and developing outbreaks.

Disclosures

All authors: No reported disclosures.

Trends and prediction of antimicrobial susceptibility in urinary bacteria isolated in European emergency departments: the EuroUTI 2010-2016 Study

Objectives

To assess recent trends in susceptibility to antibiotics among urinary isolates isolated in European emergency departments (EDs) and to identify isolates with a high (90% or more) predicted probability of susceptibility to fluoroquinolones or third-generation cephalosporins (3GCs).

Methods

In this cross-sectional study, we included urine cultures obtained from adult patients between 2010 and 2016 in 24 European EDs. Temporal trends were assessed using time-series analysis and multivariate logistic models. Multivariate logistic models were also used to predict susceptibility to fluoroquinolones or 3GCs from patient age and sex, year, month and ED.

Results

We included 88242 isolates. Time-series analysis found a significant increase in susceptibility to fluoroquinolones and no significant trend for susceptibility to 3GCs. Adjusting for patient age and sex, ED and organism, multivariate models showed that susceptibility to 3GCs decreased from 2014 to 2016, while susceptibility to fluoroquinolones increased in 2015 and 2016. Among isolates from 2016, multivariate models predicted high probability of susceptibility to fluoroquinolones in 11% of isolates (positive predictive value 91%) and a high probability of susceptibility to 3GCs in 35% of isolates (positive predictive value 94%).

Conclusions

Susceptibility of ED urinary isolates to fluoroquinolones increased from 2014, while susceptibility to 3GCs decreased from 2015. Predictive models identified isolates with a high probability of susceptibility to fluoroquinolones or 3GCs. The ability of such models to guide the empirical treatment of pyelonephritis in the ED remains to be determined.

Multiplex Platforms for the Identification of Respiratory Pathogens: Are They Useful in Pediatric Clinical Practice?

Respiratory tract infections (RTIs) are extremely common especially in the first year of life. Knowledge of the etiology of a RTI is essential to facilitate the appropriate management and the implementation of the most effective control measures. This perspective explains why laboratory methods that can identify pathogens in respiratory secretions have been developed over the course of many years. High-complexity multiplex panel assays that can simultaneously detect up to 20 viruses and up to four bacteria within a few hours have been marketed. However, are these platforms actually useful in pediatric clinical practice? In this manuscript, we showed that these platforms appear to be particularly important for epidemiological studies and clinical research. On the contrary, their routine use in pediatric clinical practice remains debatable. They can be used only in the hospital as they require specific equipment and laboratory technicians with considerable knowledge, training, and experience. Moreover, despite more sensitive and specific than other tests routinely used for respiratory pathogen identification, they do not offer significantly advantage for detection of the true etiology of a respiratory disease. Furthermore, knowledge of which virus is the cause of a respiratory disease is not useful from a therapeutic point of view unless influenza virus or respiratory syncytial virus are the infecting agents as effective drugs are available only for these pathogens. On the other hand, multiplex platforms can be justified in the presence of severe clinical manifestations, and in immunocompromised patients for whom specific treatment option can be available, particularly when they can be used simultaneously with platforms that allow identification of antimicrobial resistance to commonly used drugs. It is highly likely that these platforms, particularly those with high sensitivity and specificity and with low turnaround time, will become essential when new drugs effective and safe against most of the respiratory viruses will be available. Further studies on how to differentiate carriers from patients with true disease, as well as studies on the implications of coinfections and identification of antimicrobial resistance, are warranted.

Measurement and prediction of antimicrobial resistance in bloodstream infections by ESKAPE pathogens and Escherichia coli

OBJECTIVES

This study aimed to evaluate a cumulative antimicrobial resistance index (ARI) as a possible key outcome measure of antimicrobial stewardship programmes (ASPs) and a tool to predict the antimicrobial resistance (AMR) trend.

METHODS

Antimicrobial susceptibility for Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterobacter spp. and Escherichia coli (ESKAPEEc) pathogens recovered from blood cultures during a 5-year period (2014-2018) was analysed to obtain a cumulative ARI. For each antibiotic tested, a score of 0, 0.5 or 1 was assigned for susceptibility, intermediate resistance or resistance, respectively, and the ARI was calculated by dividing the sum of these scores by the number of antibiotics tested. Cumulative ARIs of ESKAPEEc micro-organisms were compared and a mathematical prediction model for AMR trend was obtained.

RESULTS

In total, 1858 ESKAPEEc isolates were included in the study. The cumulative ESKAPEEc mean ARI increased significantly from 0.200 ± 0.01 in 2014 to 0.276 ± 0.02 in 2018 (P < 0.001). In multivariable regression analysis, factors significantly associated with ARI ≥ 0.5 were E. faecium, K. pneumoniae, P. aeruginosa and A. baumannii infection (P < 0.001) and infection occurring after 2014 (P < 0.05). Based on the prediction model obtained, in the absence of any interventional measure, a tendency to pandrug resistance of the ESKAPEEc group could be expected in the next 8-15 years.

CONCLUSION

The ARI could be a useful tool to measure the impact of ASPs on AMR. The increasing incidence of AMR among ESKAPEEc organisms underscores the needing for ASPs.

Approach to Neonates and Young Infants with Fever without a Source Who Are at Risk for Severe Bacterial Infection

INTRODUCTION

Among neonates and infants <3 months of age with fever without a source (FWS), 5% to 15% of cases are patients with fever caused by a serious bacterial infection (SBI). To favour the differentiation between low- and high-risk infants, several algorithms based on analytical and clinical parameters have been developed. The aim of this review is to describe the management of young infants with FWS and to discuss the impact of recent knowledge regarding FWS management on clinical practice.

MATERIALS AND METHODS

PubMed was used to search for all of the studies published over the last 35 years using the keywords: "fever without source" or "fever of unknown origin" or "meningitis" or "sepsis" or "urinary tract infection" and "neonate" or "newborn" or "infant <90 days of life" or "infant <3 months".

RESULTS AND DISCUSSION

The selection of neonates and young infants who are <3 months old with FWS who are at risk for SBI remains a problem without a definitive solution. The old Rochester criteria remain effective for identifying young infants between 29 and 60 days old who do not have severe bacterial infections (SBIs). However, the addition of laboratory tests such as C-reactive protein (CRP) and procalcitonin (PCT) can significantly improve the identification of children with SBI. The approach in evaluating neonates is significantly more complicated, as their risk of SBIs, including bacteremia and meningitis, remains relevant and none of the suggested approaches can reduce the risk of dramatic mistakes. In both groups, the best antibiotic must be carefully selected considering the clinical findings, the laboratory data, the changing epidemiology, and increasing antibiotic resistance of the most common infectious bacteria.

Carbapenemase-producing Enterobacteriaceae isolates resistant to last-line antibiotics in an Italian general hospital

The global dissemination of carbapenemase-producing Enterobacteriaceae (CPE) is of great concern for public health. These bacteria have the potential for rapid dissemination in healthcare settings and cause infections associated with high rates of morbidity and mortality. A total of 221 carbapenem non-susceptible Enterobacteriaceae isolates were collected from patients admitted to an Italian general hospital from January 2016 to March 2017. Among these isolates, 78.3% were carbapenemase producers: 96% were positive for the blaKPC gene and the remainder for the blaVIM gene (allelic variant VIM-1). CPE isolates were mainly Klebsiella pneumoniae, but we also detected carbapenemase enzymes in Citrobacter freundii, Enterobacter cloacae and Escherichia coli. Among CPE isolates, 79.2% exhibited co-resistance to two or more non-b-lactam agents and 38% of these isolates (all KPC-positive) were resistant to colistin. This percentage reached 55% among CPE isolated from the bloodstream. All patients with colistin-resistant CPE isolates recovered from blood samples showed an unfavorable outcome within 7 days from the first positive blood culture. Our data show the dissemination of a high percentage of CPE isolates co-resistant to last-line antibiotics. In addition, we report the first identification in our hospital of CPE isolates harboring the blaVIM gene and Escherichia coli harboring the blaKPC gene. These results underline the need to implement antibiotic stewardship and infection control programs, and emphasize the need for novel antimicrobial agents active against CPE.

Epitope unmasking in vulvovaginal candidiasis is associated with hyphal growth and neutrophilic infiltration

Vaginal candidiasis is a common disorder in women of childbearing age, caused primarily by the dimorphic fungus Candida albicans. Since C. albicans is a normal commensal of the vaginal mucosa, a long-standing question is how the fungus switches from being a harmless commensal to a virulent pathogen. Work with human subjects and in mouse disease models suggests that host inflammatory processes drive the onset of symptomatic infection. Fungal cell wall molecules can induce inflammation through activation of epithelial and immune receptors that trigger pro-inflammatory cytokines and chemokines, but pathogenic fungi can evade recognition by masking these molecules. Knowledge about which cell wall epitopes are available for immune recognition during human infection could implicate specific ligands and receptors in the symptoms of vaginal candidiasis. To address this important gap, we directly probed the surface of fungi present in fresh vaginal samples obtained both from women with symptomatic Candida vaginitis and from women that are colonized but asymptomatic. We find that the pro-inflammatory cell wall polysaccharide β-glucan is largely masked from immune recognition, especially on yeast. It is only exposed on a small percentage of hyphal cells, where it tends to co-localize with enhanced levels of chitin. Enhanced β-glucan availability is only found in symptomatic patients with strong neutrophil infiltration, implicating neutrophils as a possible driver of these cell wall changes. This is especially interesting because neutrophils were recently shown to be necessary and sufficient to provoke enhanced β-glucan exposure in C. albicans, accompanied by elevated immune responses. Taken together, our data suggest that the architecture of C. albicans cell wall can be altered by environmental stress during vaginal candidiasis.

Molecular Characterization of Penicillinase-Producing Neisseria gonorrhoeae Isolated in Two Time Periods, 2003-2004 and 2014-2015, in Italy

The emergence of antibiotic resistant strains poses a great concern for gonorrhea treatment. The aim of this study was to characterize penicillinase-producing Neisseria gonorrhoeae (PPNG) isolates collected in Italy in two time frames, 2003-2004 and 2014-2015. A total of 80 PPNG were characterized for the bla_TEM gene variant and the plasmid type. Furthermore, gonococci were typed using Neisseria gonorrhoeae multiantigen sequence typing. Antibiotic susceptibility assay was performed for penicillin, ciprofloxacin, ceftriaxone, and spectinomycin by Etest and minimum inhibitory concentration (MIC) test strip methods. The β-lactamase production was detected using nitrocefin test. Among PPNG isolates, four bla_TEM alleles were identified as follows: bla_TEM-1, bla_TEM-228, bla_TEMP14S, and bla_TEM-135. The African plasmid possessed the bla_TEM-1, bla_TEM-228, and bla_TEMP14S, whereas bla_TEM-135 was identified in Toronto/Rio and Asian plasmids. The percentage of isolates with the bla_TEM-1-carrying African plasmid increased from 42.5% in 2003-2004 to 55% in 2014-2015; conversely, the isolates with bla_TEM-135-carrying Toronto/Rio plasmid decreased from 57.5% to 35%. Among the isolates carrying the Toronto/Rio plasmids possessing bla_TEM-135, sequence type (ST)661 and ST5624 were found to be the predominant STs in both periods 2003-2004 and 2014-2015, respectively. More than half of the PPNG isolates were resistant to ciprofloxacin. Increase in the isolates carrying the African plasmid possessing bla_TEM-1 and a parallel decrease of the bla_TEM-135-carrying Toronto/Rio plasmid was observed. Moreover, PPNG isolate harbored Toronto/Rio plasmid with bla_TEM-135 belonged mainly to two major STs (ST661 and ST5624). Given the possible role of a mutated bla_TEM gene as an additional mechanism to extended spectrum β-lactamase resistance, it is crucial to monitor gonococci carrying these resistance genes.

NLRP3 inflammasome is a key player in human vulvovaginal disease caused by Candida albicans

The expression of host inflammatory and Candida albicans putative virulence factors was studied in women with vulvovaginal candidiasis (VVC; twenty) or colonized by the fungus but asymptomatic (carriers; fifteen) or non-colonized asymptomatic (ten subjects). Overexpression of genes encoding NLRP3 and caspase-1 inflammasome components sharply differentiated VVC patients from asymptomatic colonized or non-colonized women. Inflammasome expression was coupled with neutrophils recruitment in the vagina of VVC women and IL-1β and IL-8 production. Both cytokines were present, though to a lower concentration, also in the vaginal fluid of colonized and non-colonized women. Secretory aspartyl proteinases (SAPs) and hyphae associated genes HWP1 and ECE1 were upregulated in VVC but with some differences among infected women. The most overexpressed SAP gene was SAP2, that correlated with neutrophils accumulation. Our data provide clinical evidence that the intracytoplasmic activation of NLRP3 inflammasome complex plays a critical, pathogenesis-relevant role in human VVC.

Time trend analysis (2009-2016) of antimicrobial susceptibility in Neisseria gonorrhoeae isolated in Italy following the introduction of the combined antimicrobial therapy

Introduction

Neisseria gonorrhoeae (NG) antimicrobial susceptibility trends to azithromycin, cefixime and ceftriaxone were analyzed, from 2009 to 2016, to monitor changing antimicrobial susceptibility concomitant with the change in prescribing practice in 2012 from cefixime, or ceftriaxone, to ceftriaxone plus azithromycin. Patient characteristics predictive to be infected by antibiotic resistant N. gonorrhoeae were estimated. Finally, the protocol for the treatment of gonorrhoea, in comparison with the international guidelines, was also evaluated.

Materials and methods

Data on NG antimicrobial resistance were obtained from a network of sexually transmitted diseases clinics and other laboratories in 12 cities in Italy. We tested the 1,433 gonococci for antimicrobial susceptibility to azithromycin, cefixime and ceftriaxone using a gradient diffusion method. Logistic-regression methods with cluster robust standard errors were used to investigate the association of resistance categories with demographic and clinical patient characteristics and to assess changes in prescribing practices. To minimize bias due to missing data, all statistical models were fitted to data with forty rounds of multiple imputation, using chained equations.

Results

The percentage of isolates resistant to cefixime was 17.10% in 2009 and declined up to 1.39% in 2016; at the same time, those resistant to azithromycin was 23.68% in 2009 and 3.00% in 2012. Starting from 2013, azithromycin resistant gonococci tended to increase up to 7.44% in 2016. No ceftriaxone resistant isolates were observed. By multivariate analysis, the men who have sex with women (MSW) and women had a proportional adjusted OR of resistance of 1.25 (95%CI: 0.90; 1.73) and 1.67 (95%CI: 1.16; 2.40), respectively, in comparison with men who have sex with men (MSM). An aOR of resistance of 0.48 (95%CI: 0.21; 1.12) among NG isolated in the pharynx, compared with those isolated in genital sites, was calculated. The proportional aOR of resistance was 0.58 (95%CI: 0.38; 0.89) for presence vs absence of co-infection and 2.00 (95%CI: 1.36; 2.96) for past history vs no history of gonorrhoea.Finally, at least for the period 2013–2016, the older, subjects with anorectal or pharyngeal gonorrhoea infection, subjects with a co-infection, subjects with a previous gonorrhoea infection were not always correctly treated.

Conclusions

Overall, our findings suggest the shifts in N. gonorrhoeae susceptibility to cefixime and azithromycin in the time frame period. First of all, the increasing rate of azithromycin resistance in 2015–2016 in NG isolated in the country need to be monitor in the future. Finally, extensive information on treatment regimens may be useful to asses treatment adherence particularly for the older subjects, subjects with an anorectal or pharyngeal infection, subjects with a co-infection and subjects with a previous history of gonorrhoea. Gonorrhoea treatment strategy should be based on the evidence obtained by the local antimicrobial surveillance system and data about treatment failures.

Aqueous Humor Antimicrobial Activity: In Vitro Analysis after Topical 0.5% Chloramphenicol Application

PURPOSE

To assess aqueous humor antimicrobial activity in vitro after topical 0.5% chloramphenicol application.

MATERIALS AND METHODS

This investigation included 63 eyes from 65 cataract surgery patients. The study group of 48 eyes received preoperatively four topical applications of 0.5% chloramphenicol. The control group of 15 eyes was given no topical applications. Aqueous humor samples were collected for in vitro antimicrobial analysis using Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, and Pasteurella multocida organisms by means of disk diffusion test.

RESULTS

No inhibition halo was observed around all aqueous humor samples from all chloramphenicol-treated patients, irrespective of the sample quantity added to the paper disks, with no significant difference from aqueous humor from untreated control patients.

CONCLUSIONS

Aqueous humor displayed no bactericidal effect against any of the microorganisms evaluated after topical 0.5% chloramphenicol application.

Fatal Clostridium perfringens Septicemia After Colonoscopic Polypectomy, Without Bowel Perforation

Since its introduction, colonoscopy has played an important role as a diagnostic, therapeutic, and screening tool. In general, colonoscopy is regarded as a safe procedure, but complications may occur. The most dreaded of these complications is colonic perforation. Bacteremia postprocedure may occur, and although it is not uncommon, it rarely results in clinically significant complications. Patients with IBD (inflammatory bowel disease) are a high-risk population for bacteremia, which may leads to bowel wall overstepping by the bacteria. With regard to that, we report a fatal case of gas gangrene complicating colonoscopy polypectomy without bowel perforation in a healthy adult. To the best of our knowledge, only two other cases of retroperitoneal gas gangrene associated with colonoscopy polypectomy without bowel perforation have been described in international literature, but none of which was completed by a molecular biology analysis.

Diagnosis of Nocardia paucivorans central nervous system infection by DNA sequencing from paraffin-embedded tissue

Infections by Nocardia spp. are generally regarded as opportunistic diseases in immunocompromised patients, but can also affect immunocompetent subjects. Such infections represent an important diagnostic challenge for clinicians and microbiologists, and diagnosis is frequently delayed or even conducted post mortem. A 54-year-old man was admitted to our hospital because of ventriculitis and relapsing brain abscess. Five months prior, this patient had undergone external ventricular drain and surgery for a cerebellar abscess. Histopathology demonstrated pyogenic inflammatory reaction, microbiologic investigations proved negative and empiric antimicrobial therapy was administered for a total of eight weeks. Six weeks later, the patient developed relapsing neurologic manifestations. On reviewing the patient's clinical history it emerged that the patient had suffered pneumonia two months prior to neurosurgery, treated with amoxicillin/clavulanate 3g a day and levofloxacin 500mg a day for three weeks. On the CNS relapsing manifestations, nocardiosis was suspected and DNA sequencing from the formalin-fixed paraffin-embedded cerebellar tissue collected during neurosurgery allowed diagnosis of Nocardia paucivorans infection. The patient received medical therapy for 11 months. At follow-up, eight months after treatment was discontinued, the patient was aymptomatic. Nocardia spp. infections need to be suspected not only in immunocompromised, but also in immunocompetent patients. Proper samples need to be collected for proper microbiologic investigations. Paraffin-embedded tissue genomic sequencing can be a useful tool for diagnosis of nocardiosis.

Molecular sensitivity threshold of wet mount and an immunochromatographic assay evaluated by quantitative real-time PCR for diagnosis of Trichomonas vaginalis infection in a low-risk population of childbearing women

Vaginal trichomoniasis is a sexually transmitted infection caused by Trichomonas vaginalis, a flagellated protozoan. Diagnosis of T. vaginalis infection is mainly performed by wet mount microscopy, with a sensitivity ranging from 38% to 82%, compared to culture, still considered the gold standard. Commercial immunochromatographic tests for monoclonal-antibody-based detection have been introduced as alternative methods for diagnosis of T. vaginalis infection and have been reported in some studies to be more sensitive than wet mount. Real-time PCR methods have been recently developed, with optimal sensitivity and specificity. The aim of this study was to evaluate whether there is a molecular sensitivity threshold for both wet mount and imunochromatographic assays. To this aim, a total of 1487 low-risk childbearing women (median age 32 years, interquartile range 27-37) were included in the study, and underwent vaginal swab for T. vaginalis detection by means of a quantitative real-time PCR assay, wet mount and an immunochromatographic test. Upon comparing the results, prevalence values observed were 1.3% for real-time PCR, 0.5% for microscopic examination, and 0.8% for the immunochromatographic test. Compared to real-time PCR, wet mount sensitivity was 40% (95% confidence interval 19.1% to 63.9%) and specificity was 100% (95% CI 99.7% to 100%). The sensitivity and specificity of the immunochromatographic assay were 57.9% (95% CI 33.5% to 79.8%) and 99.9% (95% CI 99.6% to 100%), respectively. Evaluation of the wet mount results and those of immunochromatographic assay detection in relation to the number of T. vaginalis DNA copies detected in vaginal samples showed that the lower identification threshold for both wet mount (chi-square 6.1; P = 0.016) and the immunochromatographic assay (chi-square 10.7; P = 0.002) was ≥100 copies of T. vaginalis DNA/5 mcl of eluted DNA.

Diagnostic accuracy of presepsin (sCD14-ST) and procalcitonin for prediction of bacteraemia and bacterial DNAaemia in patients with suspected sepsis

Early diagnosis and prompt targeted therapy are essential for septic patients' outcome. Procalcitonin (PCT) has been shown to predict bacteraemia and bacterial DNAaemia. Presepsin, the circulating soluble form of CD14 subtype, increases in response to bacterial infections, and is considered a new, emerging, early marker for sepsis. We evaluated the diagnostic accuracy of presepsin in predicting bacteraemia and bacterial DNAaemia in 92 patients with suspected sepsis, and we compared it with that of PCT and C-reactive protein (CRP). Presepsin median values were significantly higher in bacteraemic vs non-bacteraemic patients [1290 pg ml-1, interquartile range (IQR) 1005-2041 vs 659 pg ml-1, IQR 381-979; P<0.001] and in patients with vs patients without bacterial DNAaemia (1297 pg ml-1, IQR 1001-2046 vs 665 pg ml-1, IQR 381-940; P<0.001). Receiver operating characteristics analysis showed an area under the curve (AUC) for presepsin of 0.788 [95 % confidence interval (CI): 0.687-0.889; P<0.001] in predicting bacteraemia and of 0.777 (95 % CI: 0.676-0.878; P<0.001) in predicting bacterial DNAaemia, lower, but not significantly different, than those of PCT (0.876, P=0.12 and 0.880, P=0.07, respectively). Both biomarkers performed significantly better than CRP, which had an AUC for bacteraemia of 0.602 and for DNAaemia of 0.632 (all P values <0.05). In conclusion, in patients with suspected sepsis, presepsin and PCT showed a good diagnostic accuracy in predicting both bacteraemia and bacterial DNAaemia, superior to CRP.

Pathogenic NLRP3 Inflammasome Activity during Candida Infection Is Negatively Regulated by IL-22 via Activation of NLRC4 and IL-1Ra

Candida albicans is a well-tolerated resident of human mucosal tissues. This implies that host defense mechanisms cooperate to limit inflammation while controlling fungal burden. The cytokine IL-22 and inflammasomes are essential components of the mucosal responses to C. albicans. How these components cooperate to mediate the balance of inflammation and host defense is not explored. We find that NLRP3 inflammasome activation promotes neutrophil recruitment and inflammation during infection and that this activity is counteracted by IL-22. Mechanistically, IL-22 activated NLRC4 for sustained production of the IL-1 receptor antagonist IL-1Ra, which restrained NLRP3 activity. Symptomatic infection in mice and humans occurred under conditions of IL-1Ra deficiency and was rescued in mice by replacement therapy with the recombinant IL-1Ra anakinra. Thus, pathogenic inflammasome activity during Candida infection is negatively regulated by the IL-22/NLRC4/IL-1Ra axis. Our findings offer insights into the pathogenesis of C. albicans and suggest therapeutic avenues for candidiasis.

Changing antimicrobial resistance profiles among Neisseria gonorrhoeae isolates in Italy, 2003 to 2012

The emergence of Neisseria gonorrhoeae isolates displaying resistance to antimicrobial agents is a major public health concern and a serious issue related to the occurrence of further untreatable gonorrhea infections. A retrospective analysis on 1,430 N. gonorrhoeae isolates, collected from 2003 through 2012, for antimicrobial susceptibility by Etest and molecular characterization by Neisseria gonorrhoeae multiantigen sequence typing (NG-MAST) was carried out in Italy. Azithromycin-resistant gonococci decreased from 14% in 2007 to 2.2% in 2012. Similarly, isolates with high MICs to cefixime (>0.125 mg/liter) decreased from 11% in 2008 to 3.3% in 2012. The ciprofloxacin resistance rate remains quite stable, following an increasing trend up to 64% in 2012. The percentage of penicillinase-producing N. gonorrhoeae (PPNG) significantly declined from 77% in 2003 to 7% in 2012. A total of 81 multidrug-resistant (MDR) gonococci were identified, showing 11 different antimicrobial resistance patterns. These were isolated from men who have sex with men (MSM) and from heterosexual patients. Two sequence types (STs), ST661 and ST1407, were the most common. Genogroup 1407, which included cefixime-, ciprofloxacin-, and azithromycin-resistant isolates, was found. In conclusion, a change in the antimicrobial resistance profiles among gonococci was identified in Italy together with a percentage of MDR isolates.

Procalcitonin better than C-reactive protein, erythrocyte sedimentation rate, and white blood cell count in predicting DNAemia in patients with sepsis

BACKGROUND

Procalcitonin (PCT) levels can be used to predict bacteremia and DNAemia in patients with sepsis. In this study, the diagnostic accuracy of PCT in predicting blood culture (BC) results and DNAemia, as detected by real-time PCR (RT-PCR), was compared with that of other markers of inflammation commonly evaluated in patients with suspected sepsis, such as C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), and white blood cell (WBC) count.

METHODS

A total of 571 patients for whom BC, blood RT-PCR, PCT, CRP, ESR, and WBC count were requested for laboratory diagnosis of sepsis were included in the study. Receiver operating characteristic curve analysis was performed to compare the ability of the above biomarkers to predict BC and blood RT-PCR results.

RESULTS

A total of 108 pathogens were identified by BC (79 pathogens, 14.5% positive rate) and/or RT-PCR (90 pathogens, 16.5% positive rate), after exclusion of 26 contaminated samples. The PCT areas under the curve (AUCs) in predicting BC (0.843; 95% CI 0.796-0.890; p < 0.0001) and RT-PCR (0.916; 95% CI 0.888-0.945; p < 0.0001) results were significantly greater than AUCs found for CRP, ESR, and WBC count.

CONCLUSIONS

PCT showed a better diagnostic accuracy than CRP, ESR, and WBC count in predicting DNAemia and bacteremia in patients with suspected sepsis.

Tolerability and efficacy of long-term treatment with daptomycin, ceftazidime and colistin in a patient with a polymicrobial, multidrug-resistant prosthetic joint reinfection: a case report

INTRODUCTION

Prosthetic joint infections are severe complications of joint implants. Further complications arise when polymicrobial and/or multidrug-resistant microorganisms are involved. Currently, there are limited data on the management of these infections and on the tolerability of long-term treatment with daptomycin, ceftazidime and colistin.

CASE PRESENTATION

A 55-year-old Caucasian woman who had a right hip prosthesis removed 1 year prior because of infection was admitted for prosthesis reimplantation. On admission at our hospital, anamnesis regarding etiology and management of prosthesis infection was not available. On clinical, laboratory findings and imaging studies infection was not suspected. A hip prosthesis was reimplanted. At surgery, histopathological and microbiological investigations were not taken. Three weeks after reimplantation, surgical site infection due to Enterobacter cloacae was diagnosed and oral ciprofloxacin was prescribed. Four days later, a periprosthesis fluid collection was evidenced and a percutaneous needle aspirate grew Staphylococcus epidermidis and S. haemolyticus. Enterobacter genome was also detected from the same sample. Teicoplanin and meropenem were added to ciprofloxacin without clinical improvement. Moreover, acetabular cup dislocation was documented. She underwent prosthesis explantation, debridement, and positioning of an antimicrobial mixed spacer. From the intraoperatory cultures S. epidermidis and Acinetobacter baumannii were grown. Daptomycin, ceftazidime, colistin and rifampin were administered. Four days later, rifampin was stopped due to a suspected liver toxicity. While undergoing therapy she presented recurrent episodes of wound dehiscence and on the 22nd week of treatment a further surgical debridement was performed, upon which the spacer was removed. At this time, intraoperative cultures resulted negative. Three months later, after a total of 8 months, antimicrobials were interrupted. Subsequently, a femoral transcondylar traction was positioned, and 3 weeks later a new prosthesis was reimplanted. At over 1 year after reimplantation she is well.

CONCLUSIONS

Our findings suggest that microbiologic investigations are mandatory even when prosthetic joint infection is not suspected. Molecular methods for identification of microorganisms can be used in addition to conventional cultures especially when patients are under antibiotic treatment. Daptomycin, ceftazidime and colistin can be administered for several months without side effects. Guidelines specifically addressing the diagnosis and the management of polymicrobial, multidrug-resistant prosthetic joint infections need to be developed.