Early assessment of blood culture negativity as a potential support tool for antimicrobial stewardship

Objective

To assess whether 48-h negative blood culture (BC) bottles are still negative at the classic 120-h incubation endpoint and whether 48 h might be the time to make antimicrobial therapy decisions.

Methods

Data from the first collected bottles from bloodstream infection (BSI) episodes of single patients were retrospectively analyzed. Probabilities of bottles being negative at the classic endpoint were calculated from 0 to 120 h of incubation.

Results

Among BC-negative episodes (4018/4901 [82.0%]), most (2097/4018 (52.2%) occurred in medicine patients. At 48 h, probability was 100.0% (95% CI, 99.9-100.0) for all 4018 patients. Of these, 1244 (31.0%) patients remained on antibiotics until 120 h. Excluding 401 (32.2%) patients who received antibiotics for another (non-bloodstream) infection, 843 (67.8%) of 1244 patients could have merited early (48-h) discontinuation of antibiotics. Stopping treatment in these patients would have led to saving 5201 days of access (943 [18.1%] days), watch (3624 [69.7%] days), or reserve (634 [12.2%]) AWaRe groups' antibiotics, which correspond to 65.6% (5201/7928) of days of administered antibiotics in all 1244 patients.

Conclusion

As an early indicator of BC negativity, the 48-h endpoint could reliably support antimicrobial stewardship, but the clinical judgment remains imperative especially when BSI is highly suspected.

Human Campylobacter spp. infections in Italy

PURPOSE

Campylobacter is a frequent cause of enteric infections with common antimicrobial resistance issues. The most recent reports of campylobacteriosis in Italy include data from 2013 to 2016. We aimed to provide national epidemiological and microbiological data on human Campylobacter infections in Italy during the period 2017-2021.

METHODS

Data was collected from 19 Hospitals in 13 Italian Regions. Bacterial identification was performed by mass spectrometry. Antibiograms were determined with Etest or Kirby-Bauer (EUCAST criteria).

RESULTS

In total, 5419 isolations of Campylobacter spp. were performed. The most common species were C. jejuni (n = 4535, 83.7%), followed by C. coli (n = 732, 13.5%) and C. fetus (n = 34, 0.6%). The mean age of patients was 34.61 years and 57.1% were males. Outpatients accounted for 54% of the cases detected. Campylobacter were isolated from faeces in 97.3% of cases and in 2.7% from blood. C. fetus was mostly isolated from blood (88.2% of cases). We tested for antimicrobial susceptibility 4627 isolates (85.4%). Resistance to ciprofloxacin and tetracyclines was 75.5% and 54.8%, respectively; resistance to erythromycin was 4.8%; clarithromycin 2% and azithromycin 2%. 50% of C. jejuni and C. coli were resistant to ≥ 2 antibiotics. Over the study period, resistance to ciprofloxacin and tetracyclines significantly decreased (p < 0.005), while resistance to macrolides remained stable.

CONCLUSION

Campylobacter resistance to fluoroquinolones and tetracyclines in Italy is decreasing but is still high, while macrolides retain good activity.

A Machine Learning Predictive Model of Bloodstream Infection in Hospitalized Patients

The aim of the study was to build a machine learning-based predictive model to discriminate between hospitalized patients at low risk and high risk of bloodstream infection (BSI). A Data Mart including all patients hospitalized between January 2016 and December 2019 with suspected BSI was built. Multivariate logistic regression was applied to develop a clinically interpretable machine learning predictive model. The model was trained on 2016-2018 data and tested on 2019 data. A feature selection based on a univariate logistic regression first selected candidate predictors of BSI. A multivariate logistic regression with stepwise feature selection in five-fold cross-validation was applied to express the risk of BSI. A total of 5660 hospitalizations (4026 and 1634 in the training and the validation subsets, respectively) were included. Eleven predictors of BSI were identified. The performance of the model in terms of AUROC was 0.74. Based on the interquartile predicted risk score, 508 (31.1%) patients were defined as being at low risk, 776 (47.5%) at medium risk, and 350 (21.4%) at high risk of BSI. Of them, 14.2% (72/508), 30.8% (239/776), and 64% (224/350) had a BSI, respectively. The performance of the predictive model of BSI is promising. Computational infrastructure and machine learning models can help clinicians identify people at low risk for BSI, ultimately supporting an antibiotic stewardship approach.

Changes in clinical, demographic, and outcome patterns of children hospitalized with non-SARS-CoV-2 viral low respiratory tract infections before and during the COVID pandemic in Rome, Italy

INTRODUCTION

We performed this study aiming to evaluate changes in epidemiology, clinical presentation and outcomes of children hospitalized for viral lower respiratory tract infections (LRTI).

METHODS

We performed a retrospective study of children younger than 18 years of age hospitalized for LRTIs with a positive respiratory viral testing from 2018 to 2022. We compared need of pediatric intensive care unit (PICU), invasive ventilation, and other respiratory support, viral etiologies, clinical presentations, imaging, and laboratory results in the precovid (2018-2019) and covid (2020-2022) period.

RESULTS

A total of 523 were included in the analysis. In the pandemic period, the detection of influenza was 95% less likely to occur (odds ratio [OR]: 0.05; 95% confidence interval [95% CI]: 0.02-0.12; p < .001), likewise the detection of adenovirus was 77% less likely to occur (OR: 0.23; 95% CI: 0.10-0.51; p < .001). In the pandemic period, the number of codetections increased from 15.52% in 2018 to 57.25% in 2022, resulting in a significantly increasing trend (p < .001). The odds of transfer to PICU was more than five times greater during the pandemic period (OR: 5.31; 95% CI: 1.78-15.86; p = .003).

CONCLUSIONS

We found that the pattern of LRTI in children during COVID-19 pandemic significantly changed in terms of etiologies and increased severity.

Association of piperacillin/tazobactam MIC and mortality in a cohort of ceftriaxone-resistant Escherichia coli bloodstream infections treated with piperacillin/tazobactam and carbapenems: a multicentric propensity score-weighted observational cohort study

OBJECTIVES

To assess the impact of piperacillin/tazobactam MICs on in-hospital 30 day mortality in patients with third-generation cephalosporin-resistant Escherichia coli bloodstream infection treated with piperacillin/tazobactam, compared with those treated with carbapenems.

METHODS

A multicentre retrospective cohort study was conducted in three large academic hospitals in Italy between 2018 and 2022. The study population comprised patients with monomicrobial third-generation cephalosporin-resistant E. coli bloodstream infection, who received either piperacillin/tazobactam or carbapenem therapy within 48 h of blood culture collection. The primary outcome was in-hospital 30 day all-cause mortality. A propensity score was used to estimate the likelihood of receiving empirical piperacillin/tazobactam treatment. Cox regression models were performed to ascertain risk factors independently associated with in-hospital 30 day mortality.

RESULTS

Of the 412 consecutive patients included in the study, 51% received empirical therapy with piperacillin/tazobactam, while 49% received carbapenem therapy. In the propensity-adjusted multiple Cox model, the Pitt bacteraemia score [HR 1.38 (95% CI, 0.85-2.16)] and piperacillin/tazobactam MICs of 8 mg/L [HR 2.35 (95% CI, 1.35-3.95)] and ≥16 mg/L [HR 3.69 (95% CI, 1.86-6.91)] were significantly associated with increased in-hospital 30 day mortality, while the empirical use of piperacillin/tazobactam was not found to predict in-hospital 30 day mortality [HR 1.38 (95% CI, 0.85-2.16)].

CONCLUSIONS

Piperacillin/tazobactam use might not be associated with increased mortality in treating third-generation cephalosporin-resistant E. coli bloodstream infections when the MIC is <8 mg/L.

Epidemiology, time course, and risk factors for hospital-acquired bloodstream infections in a cohort of 14,884 patients before and during the COVID-19 pandemic

OBJECTIVE

COVID-19 pandemic has changed in-hospital care and was linked to superimposed infections. Here, we described epidemiology and risk factors for hospital-acquired bloodstream infections (HA-BSIs), before and during COVID-19 pandemic.

METHODS

This retrospective, observational, single-center real-life study included 14,884 patients admitted to hospital wards and intensive care units (ICUs) with at least one blood culture, drawn 48 h after admission, either before (pre-COVID, N = 7382) or during pandemic (N = 7502, 1203 COVID-19+ and 6299 COVID-19-).

RESULTS

Two thousand two hundred and forty-five HA-BSI were microbiologically confirmed in 14,884 patients (15.1%), significantly higher among COVID-19+ (22.9%; ptrend < .001). COVID-19+ disclosed a significantly higher mortality rate (33.8%; p < .001) and more ICU admissions (29.7%; p < .001). Independent HAI-BSI predictors were: COVID-19 (OR: 1.43, 95%CI: 1.21-1.69; p < .001), hospitalization length (OR: 1.04, 95%CI: 1.03-1.04; p < .001), ICU admission (OR: 1.38, 95%CI: 1.19-1.60; p < .001), neoplasms (OR:1.48, 95%CI: 1.34-1.65; p < .001) and kidney failure (OR: 1.81, 95%CI: 1.61-2.04; p < .001). Of note, HA-BSI IRs for Acinetobacter spp. (0.16 × 100 patient-days) and Staphylococcus aureus (0.24 × 100 patient-days) peaked during the interval between first and second pandemic waves in our National context.

CONCLUSIONS

Patients with HA-BSI admitted before and during pandemic substantially differed. COVID-19 represented a risk factor for HA-BSI, though not confirmed in the sole pandemic period. Some etiologies emerged between pandemic waves, suggesting potential COVID-19 long-term effect on HA-BSIs.

Single-center, prospective, and observational study on the management and treatment of impetigo in a pediatric population

OBJECTIVE

Ozenoxacin is a new antibiotic used to treat non-bullous impetigo. The aim of this study is to evaluate the microbiological and clinical efficacy of topical ozenoxacin 1% cream after 5-day twice-daily treatment, in pediatric patients with impetigo.

PATIENTS AND METHODS

This observational and prospective study included patients aged 6 months to 18 years, with non-bullous impetigo. Efficacy was measured using the Skin Infection Rating Scale (SIRS) and microbiological culture at the first visit (T0), at the second visit after 72 hours (T1) and after 5 days (T2). Safety and tolerability were also evaluated.

RESULTS

A total of 50 patients was enrolled. A reduction of SIRS score >10% after 72 hours of treatment was noticed in all patients, while a complete reduction was assessed after 5 days in all the population. Microbiologic success rates for ozenoxacin at T1 was 92% (four patients had original pathogens in the specimen culture from the skin area), whereas at T2, it was 100%.

CONCLUSIONS

Topical ozenoxacin has strong efficacy in treating impetigo in pediatric patients. Ozenoxacin's clinical and microbiological rapid onset of response led to consider this antibiotic a novel efficacy option for the treatment of impetigo.

Retrospective Study on Staphylococcus aureus Resistance Profile and Antibiotic Use in a Pediatric Population

The growing phenomenon of antibiotic resistance and the presence of limited data concerning the pediatric area prompted us to focus on Staphylococcus aureus infection in this study, its antibiotic resistance profile, and the therapeutic management of affected children. We conducted a retrospective study by collecting clinical data on infants and children with antibiogram-associated S. aureus infection. We enrolled 1210 patients with a mean age of 0.9 years. We analyzed the resistance patterns and found 61.5% resistance to oxacillin, 58.4% resistance to cephalosporins, 41.6% resistance to aminoglycosides, and 38.3% resistance to fluoroquinolones. Importantly, we found no resistance to glycopeptides, a key antibiotic for MRSA infections whose resistance is increasing worldwide. We also found that the main risk factors associated with antibiotic resistance are being aged between 0 and 28 days, the presence of devices, and comorbidities. Antibiotic resistance is a growing concern; knowing the resistance profiles makes it possible to better target the therapy; however, it is important to use antibiotics according to the principles of antibiotic stewardship to limit their spread.

Respiratory viruses in the pre and post-pandemic periods in an Italian tertiary hospital

We have appreciated the article published by Bardsley and colleagues describing the seasonal circulation of respiratory syncytial virus (RSV) in UK children, and we hope to contribute to increase information on this intriguing and elusive topic. We describe our epidemiological trend with the aim to add a small brick to the current knowledge regarding respiratory infections due to RSV and other respiratory viruses in an era that is changing due to a radical change in the evaluation of respiratory symptoms following the pandemic event.

Incidence of bloodstream infections due to multidrug-resistant pathogens in ordinary wards and intensive care units before and during the COVID-19 pandemic: a real-life, retrospective observational study

PURPOSE

SARS-COV-2 pandemic led to antibiotic overprescription and unprecedented stress on healthcare systems worldwide. Knowing the comparative incident risk of bloodstream infection due to multidrug-resistant pathogens in COVID ordinary wards and intensive care-units may give insights into the impact of COVID-19 on antimicrobial resistance.

METHODS

Single-center observational data extracted from a computerized dataset were used to identify all patients who underwent blood cultures from January 1, 2018 to May 15, 2021. Pathogen-specific incidence rates were compared according to the time of admission, patient's COVID status and ward type.

RESULTS

Among 14,884 patients for whom at least one blood culture was obtained, a total of 2534 were diagnosed with HA-BSI. Compared to both pre-pandemic and COVID-negative wards, HA-BSI due to S. aureus and Acinetobacter spp. (respectively 0.3 [95% CI 0.21-0.32] and 0.11 [0.08-0.16] new infections per 100 patient-days) showed significantly higher incidence rates, peaking in the COVID-ICU setting. Conversely, E. coli incident risk was 48% lower in COVID-positive vs COVID-negative settings (IRR 0.53 [0.34-0.77]). Among COVID + patients, 48% (n = 38/79) of S. aureus isolates were resistant to methicillin and 40% (n = 10/25) of K. pneumoniae isolates were resistant to carbapenems.

CONCLUSIONS

The data presented here indicate that the spectrum of pathogens causing BSI in ordinary wards and intensive care units varied during the pandemic, with the greatest shift experienced by COVID-ICUs. Antimicrobial resistance of selected high-priority bacteria was high in COVID positive settings.

COVID-19 increased in Italian children in the autumn and winter 2021-2022 period when Omicron was the dominant variant

AIM

We examined the prevalence of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in children during the autumn and winter season from 1 September 2021 to 30 January 2022 and compared it with the same period in 2020-2021.

METHODS

This study was carried out int the paediatric emergency department (PED) of a tertiary Italian hospital. We compared the clinical and demographical features of all children who presented during the two study periods and tested positive for SARS-CoV-2.

RESULTS

During the 2021-2022 autumn and winter season 5813 children presented to the PED, 19.0% were tested for SARS-CoV-2 and 133 (12.0%) of those tested positive. In 2020-2021, 2914 presented to the PED, 12.3% were tested, and 30 (8.3%) of those tested positive. There were no statistically significant differences in clinical severity during the two study periods, despite a higher percentage of neurological symptoms in 2020-2021. Of the SARS-CoV-2-positive cases, 29/133 (21.8%) were hospitalised during the 2021-2022 season and 10/30 (33.3%) during the previous one. Only 3/163 children required intensive care.

CONCLUSION

The greater spread of SARS-CoV-2 was probably due to the greater transmissibility of the Omicron variant, but the symptoms were mild and only 3 children required intensive care.

Efficient Recovery of Candida auris and Five Other Medically Important Candida Species from Blood Cultures Containing Clinically Relevant Concentrations of Antifungal Agents

Candida auris and other Candida species (C. albicans, C. glabrata, C. parapsilosis, C. tropicalis, and C. krusei) are important causes of bloodstream infection. Early or prolonged treatment with antifungal agents is often required. The inhibitory effect of antifungal agents in the patients' bloodstream may compromise the sensitivity of blood culture (BC) to diagnose and/or monitor patients with candidemia. Using a clinical BC simulation model, we compared antimicrobial drug-neutralizing BC media in BacT/Alert FA PLUS (FAP) or Bactec Plus Aerobic/F (PAF) bottles with non-neutralizing BC media in Bactec Mycosis IC/F (MICF) bottles to allow Candida growth in the presence of 100%, 50%, or 25% peak serum level (PSL) antifungal concentrations. In total, 117 organism/antifungal combinations were studied, and Candida growth was detected after incubating bottles into BacT/Alert VIRTUO or Bactec FX BC systems. Compared to control (without antifungal) bottles, both FAP and PAF bottles with 100% PSL antifungal concentrations allowed 100% recovery for C. auris, C. glabrata, and C. parapsilosis, whereas recovery was below 100% for C. albicans, C. krusei, and C. tropicalis. MICF bottles were less efficient at 100%, 50%, or 25% PSL antifungal concentrations, for all Candida species, except for C. auris. While azoles and amphotericin B did not hinder Candida growth in FAP or PAF bottles, echinocandins allowed C. auris, C. glabrata, and C. parapsilosis to grow in FAP, PAF, or MICF bottles. Overall, the maximum time to detection was 4.6 days. Taken together, our findings emphasize the reliability of BCs in patients undergoing antifungal treatment for candidemia. IMPORTANCE While echinocandins remain the preferred antifungal therapy for candidemia, bloodstream infections caused by C. auris, C. glabrata, or, at a lesser extent, C. parapsilosis may be difficult to treat with these antifungal agents. This is in view of the high propensity of the above-mentioned species to develop antifungal resistance or tolerance during treatment. Azoles and amphotericin B are possible alternatives. Thus, optimizing the recovery of Candida from BCs is important to exclude the likelihood of negative BCs for Candida species, owing to the inhibitory effect of antifungal agents present in the blood sample with which BCs are inoculated. Consistently, our results about the recovery of medically important Candida species (including C. auris) from simulated BCs in BacT/Alert FAP, Bactec PAF, or Bactec MICF bottles containing clinically relevant antifungal concentrations add support to this research topic, as well as to the use of BCs for monitoring the clinical and therapeutic course of candidemia.

Susceptibility of Meropenem-Resistant and/or Carbapenemase-Producing Clinical Isolates of Enterobacterales (Enterobacteriaceae) and Pseudomonas aeruginosa to Ceftazidime-Avibactam and Ceftolozane-Tazobactam as Assessed by In Vitro Testing Methods

This study aimed to assess the comparability of in vitro susceptibility testing methods to ceftazidime-avibactam (CZA) and ceftolozane-tazobactam (C/T). Meropenem-resistant and/or carbapenemase-producing clinical isolates of Enterobacterales (Enterobacteriaceae) and Pseudomonas aeruginosa were tested by both bioMérieux ETEST and VITEK-2 AST-N397 card and compared with a Micronaut AST-system broth microdilution (BMD) method. CZA and C/T MICs were interpreted using EUCAST breakpoints. Of the 153 Enterobacteriaceae isolates, 55.6% and 0.0% (VITEK 2) and 56.9% and 0.0% (ETEST and BMD) were susceptible to CZA and C/T, respectively. Of 52 P. aeruginosa isolates, 50.0% and 40.4% (VITEK 2, ETEST, and BMD) were susceptible to CZA and C/T, respectively. The essential agreement (EA) was 96.1% (197/205; VITEK 2 versus BMD) and 95.6% (196/205; ETEST versus BMD) for CZA testing, whereas EA was 98.0% (201/205; VITEK 2 versus BMD) and 96.6% (198/205; ETEST versus BMD) for C/T testing. The categorical agreement (CA) was 98.0% (201/205; VITEK 2 versus BMD) and 100% (ETEST versus BMD) for CZA testing, whereas CA was 100% (VITEK 2 versus BMD) and 100% (ETEST versus BMD) for C/T testing. Categorical errors regarded four Enterobacteriaceae isolates. VITEK 2 and ETEST yielded equivalent CZA and C/T susceptibility testing results, compared to the BMD method, in such a clinical context.

Characteristic of IgA and IgG antibody response to SARS-CoV-2 infection in an Italian referral COVID-19 Hospital

INTRODUCTION

Antibody response plays a fundamental role in the natural history of infectious disease. A better understanding of the immune response in patients with SARS-CoV-2 infection could be important for identifying patients at greater risk of developing a more severe form of disease and with a worse prognosis.

METHODS

We performed a cross-sectional analysis to determine the presence and the levels of both anti-SARS-CoV-2 IgG and IgA in a cohort of hospitalized patients with confirmed infection at different times in the natural history of the disease. Patients enrolled when admitted at the emergency department were prospectively followed up during hospital stay.

RESULTS

Overall, 131 patients were considered with a total of 237 samples processed. Cross-sectional analysis showed that seroconversion for IgA seems to occur between days 6 and 15, while IgG response seems to occur slightly later, peaking at day 20 after symptoms onset. Both IgA and IgG were maintained beyond 2 months. Severe patients showed a higher IgA response compared with mild patients when analyzing optical density (8.3 versus 5.6, p < 0.001). Prospective analysis conducted on 55 patients confirmed that IgA appear slightly earlier than IgG. After stratifying for the severity of disease, both the IgA and IgG responses were more vigorous in severe cases. Moreover, while IgG tended to stabilize, there was a relevant decline after the first month of IgA levels in mild cases.

CONCLUSION

IgA and IgG antibody response is closely related, although seroconversion for IgA occurs earlier. Both IgA and IgG are maintained beyond 2 months. Severe patients showed a more vigorous IgA and IgG response. IgA levels seem to decline after 1 month since the onset of symptoms in mild cases. Our results should be interpreted with cautions due to several limitations in our study, mainly the small number of cases, lack of data on viral load and clinical setting.

Escherichia coli resistance patterns, empiric and targeted antibiotic prescriptions in children: a single center experience

BACKGROUND AND AIM

Antibiotic resistance represents one of the major public health issues, due to the potential future ineffectiveness of available antibiotics. However, epidemiological studies on E. coli antibiotic resistance patterns in the pediatric population are limited.

METHODS

We conducted a retrospective analysis on children younger than 18 years of age admitted to the Department of Pediatrics from April 2016 to April 2018 with E. coli isolation on biological materials.

RESULTS

205 subjects were included in the study (mean age 1.6 years). We found an overall low rate of resistance of E. coli isolates to Amoxicil-lin/Clavulanate (20%), Cephalosporins (6.3%) and Aminoglycosides (6.3%), while no isolates were resistant to Carbapenems. Presence of invasive devices and intensive care admissions were as-sociated with resistance to Cephalosporines (P < 0.001; OR 9.21, 95% CI 2.7 - 31.39) and Amino-glycosides (P < 0.004; OR 5.42, 95% CI 1.71 - 17.15), while no factors associated with resistance to the other antibiotics were found.

CONCLUSIONS

Aminoglycosides and Cephalosporins were frequently used as empiric therapy, whereas targeted therapies aimed at sparing these classes of antibiotics once antibiograms were available have not always been established. These data may inform local antimicrobial stewardship and guide the development of programs aiming at a better use of antibiotics.

Protective effect of SARS-CoV-2 preventive measures against ESKAPE and Escherichia coli infections

BACKGROUND/OBJECTIVES

We investigated whether behavioral precautions adopted during Coronavirus disease (COVID-19) pandemic also influenced the spreading and multidrug resistance (MDR) of ESKAPEEc (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii [AB], Pseudomonas aeruginosa, Enterobacter spp and Escherichia Coli, [EC]) among Intensive Care Unit (ICU) patients.

SUBJECTS/METHODS

We performed a single-center retrospective study in adult patients admitted to our COVID-19-free surgical ICU. Only patients staying in ICU for more than 48 hours were included. The ESKAPEEc infections recorded during the COVID-19 period (June 1, 2020 - February 28, 2021) and in the corresponding pre-pandemic period (June 1, 2019 - February 28, 2020) were compared. An interrupted time series analysis was performed to rule out possible confounders.

RESULTS

Overall, 173 patients in the COVID-19 period and 132 in the pre-COVID-19 period were investigated. The ESKAPEEc infections were documented in 23 (13.3%) and 35 (26.5%) patients in the pandemic and the pre-pandemic periods, respectively (p = 0.005). Demographics, diagnosis, comorbidities, type of surgery, Simplified Acute Physiology Score II, length of mechanical ventilation, hospital and ICU length of stay, ICU death rate, and 28-day hospital mortality were similar in the two groups. In comparison with the pre-pandemic period, no AB was recorded during COVID-19 period, (p = 0.017), while extended-spectrum beta-lactamase-producing EC infections significantly decreased (p = 0.017). Overall, the ESKAPEEc isolates during pandemic less frequently exhibited multidrug-resistant (p = 0.014).

CONCLUSIONS

These findings suggest that a robust adherence to hygiene measures together with human contact restrictions in a COVID-19 free ICU might also restrain the transmission of ESKAPEEc pathogens.

From infections to preventive actions monitoring in health facilities: an experience on MDROs

 

Healthcare-Associated Infections (HAIs) and Antimicrobial Resistance (AMR) involve high costs both in health and economic terms for patients and health systems. Implementing Infection Prevention and Control (IPC) programs is critical to decrease infectious agents' transmission in healthcare settings. The aim of this study is to assess if the monitoring of Contact Precautions could decrease the incidence of Multi-Drug Resistant Organisms (MRDOs) infections. This pilot study was conducted in a teaching hospital in Rome. A checklist of 16 items was developed to assess the compliance to Contact Precautions in 11 hospital wards in which MRDOs were detected between November and December 2020. It was administered on-site both interviewing healthcare professionals and through direct observation. A paired t-test with α = 5% was used to compare the number of alert organisms in the first quarter of 2020 respect to the first quarter of 2021 before and after implementing the surveillance checklist. A total of 30 checklists were analyzed. The rate of compliance to Contact Precautions was high for the proper use of personal protective equipment (100%), the intensified room cleaning (100%) and the presence of isolation mark (100%), while it was low for the active screening of contacts (53%). Mean MDROs infections rate decreased from 4.94 to 4.37 for every 1000 hospitalization day, with an average decrease of 0.57. However, the paired t-test showed that there was no statistically significant difference between the mean number of MDROs infections before and after the implementation of the checklist (p > 0.05). Despite the good adherence to IPC program, the low infection rate decrease, is probably due to the impact of COVID-19 on the HAIs surveillance and prevention practices. Even if the check-list administration could be a useful tool to reduce MDROs infections, it should be associated to other prevention strategies during the COVID-19 pandemic in order to achieve a successful outcome.

Key messages

Preventing Healthcare-Associated Infections represents a priority public health challenge in order to improve patient safety and health system economic sustainability.

The COVID-19 pandemic has shown that healthcare facilities should enhance efforts in their IPC programs to reduce Healthcare-Associated Infections.

Time to Positivity of Blood Cultures Could Inform Decisions on Antibiotics Administration in Neonatal Early-Onset Sepsis

(1) Background: Empirical antibiotics for suspected neonatal early-onset sepsis are often prolonged administered, even in the absence of clinical signs of infection, while awaiting the blood cultures results. The C-reactive protein is widely used to guide antibiotic therapy, although its increase in the first hours of life is not always evidence of infection. The aim of this study was to evaluate the time to positivity (TTP) of blood cultures (BC) that develop pathogens in our population of neonates and determine whether TTP could safely inform the decisions on empirical antibiotic discontinuation in neonatal early-onset sepsis and reduce the use of unnecessary antibiotics. (2) Methods: We retrospectively collected data of all newborns ≥ 34 weeks admitted to the Neonatal Intermediate-Care Unit at Policlinico “A. Gemelli” University Hospital (Rome, Italy) from 2014 to 2018, with suspected early-onset sepsis (EOS). The TTP was the time in hours from the first BC inoculation to the bacterial growth. We defined as positive BC only those with a pathogenic organism. (3) Results: In total, 103 out of 20,528 infants born in the five-year study period were admitted to our Neonatal Intermediate-Care Unit because of a suspected EOS and enrolled into the study. The mean TTP of pathogenic organisms was 17.7 ± 12.5 h versus 80.5 ± 55.8 h of contaminants (p = 0.003). We found ten positive BCs. The TTP of BC was lower than 12, 36, and 48 h in 80%, 90%, and 100% of cases, respectively. CRP levels on admission were similar in infants with a positive and negative BC (p = 0.067). The discontinuation of therapy in asymptomatic infants 48 h after initiation would have resulted in a saving of 217 days of antibiotics (31.1% of total days administered). (4) Conclusion: From our data, the TTP of blood cultures that develop pathogens is less than 48 h in 100% of cases. Therefore, in late preterm and full-term infants with suspected EOS, stopping empiric antibiotics 48 h after initiation may be a safe practice to reduce unnecessary antibiotic use, when blood cultures are negative and infants asymptomatic.

Reduction of bacterial colonization at the exit site of peripherally inserted central catheters: A comparison between chlorhexidine-releasing sponge dressings and cyano-acrylate

INTRODUCTION

A serious complication associated with Central Venous Access Device (CVAD) is infection because of bacterial contamination, either by the extra-luminal or by the intra-luminal route.We evaluated the efficacy, the safety, and the cost-effectiveness of two strategies for non-inferiority in controlling bacterial colonization of the exit-site of Peripherally-Inserted Central Catheters (PICC).

METHODS

After PICC placement, a skin swab of the exit site was taken and cultured. In group A the exit site was sealed with N-butyl-cyanoacrylate glue, while in group B a chlorhexidine-releasing sponge dressing was applied. A second skin culture was taken at day 7.

RESULTS

A total of 51 patients were enrolled in each group. In 42 patients the second skin culture was not performed because of 20 patients were lost at follow-up or deceased and in 22 patients the dressing needed to be changed early, because of local bleeding (13 cases, in group B) or because of dressing detachment (four in group A and five in group B). The microbiological study was completed in 36 patients in group A and 24 in group B. No microorganisms were isolated in any patient.

CONCLUSIONS

Both strategies were effective in controlling bacterial colonization. Glue was effective in reducing local bleeding, and it was more cost-effective than sponge dressing. During the first week, when local bleeding and bacterial colonization must be prevented, glue might be more appropriate than chlorhexidine-releasing dressing; after the first week chlorhexidine-releasing dressing might be preferable, considering that the safety of glue application on the skin for prolonged periods is still questionable.

Diabetic foot infections: a comprehensive overview

Diabetic foot ulcers (DFUs), a micro-vascular complication, are associated with a substantial increase in morbidity and mortality. DFUs are a complicated mixture of neuropathy, peripheral arterial diseases, foot deformities, and infections. Foot infections are frequent and potentially devastating complications. Infection prospers in more than half of all foot ulcers and is the factor that most often leads to lower extremity amputation. The complications of microbial flora span the spectrum from superficial cellulitis to chronic osteomyelitis and gangrenous extremity lower limb amputations. Wounds without confirmed soft tissue or bone infections do not require antibiotic therapy. Mild and moderate infections need empiric therapy covering Gram-positive cocci, while severe infections caused by drug-resistant organisms require broad-spectrum anti-microbials targeting aggressive Gram-negative aerobes and obligate anaerobes.

Characterisation and risk factor profiling of Pseudomonas aeruginosa urinary tract infections: pinpointing those likely to be caused by multidrug-resistant strains

This study aimed to characterise UTIs caused by Pseudomonas aeruginosa in hospitalised adults and to identify risk factors for infections caused by multidrug-resistant (MDR) strains. A retrospective case-case-control study was conducted in two Italian teaching hospitals. Totally, 242 monomicrobial P. aeruginosa UTIs were analysed; 65 (26.9%) were caused by MDR strains. Clinical treatment failure at 72 h in 215 patients receiving empirical therapy was more frequent in MDR versus non-MDR cases [35/59 (59.3%) vs. 55/156 (35.3%); P = 0.001], particularly when a β-lactam/β-lactamase inhibitor or fluoroquinolone was initially prescribed. By Day 7 (when all regimens were consistent with antimicrobial susceptibility results), treatment failure rates were similar [MDR 15/65 (23.1%) vs. non-MDR 25/177 (14.1%); P = 0.09]. In-hospital mortality rates remained low in both groups [6/65 (9.2%) vs. 22/177 (12.4%); P = 0.49], but median hospital stay for MDR cases was longer (48 vs. 22 days; P ≤ 0.001). Models for predicting MDR and non-MDR P. aeruginosa UTIs displayed good discriminatory power. Presence of ≥3 risk factors for MDR P. aeruginosa UTI was associated with an OR for this outcome of 7.44 (95% CI 3.24-17.57; P < 0.001; specificity 91%, accuracy 75%). The model for predicting non-MDR P. aeruginosa UTI displayed similar accuracy (74%) with a risk factor burden threshold of ≥2 (OR = 7.02, 95% CI 4.61-10.70; P < 0.001). Risk factor assessment can identify UTIs in hospitalised patients likely to be caused by MDR P. aeruginosa, thereby facilitating targeted infection control and timelier effective treatment.

Age-related Trends in Adults with Urinary Tract Infections Presenting to the Emergency Department: A 5-Year Experience

INTRODUCTION

Urinary tract infections (UTIs) are among the most common bacterial infections, affecting 150 million people worldwide each year. Importantly, the incidence of UTI increases markedly with age. The increasing resistance to empirically prescribed antimicrobial agents complicates the management of this disease. This makes UTI an important issue in increasingly aging population and updated epidemiological investigation is advisable. To understand the epidemiological variation in UTI resistance patterns among differently aged populations, we conducted a retrospective study among patients presenting to the emergency department (ED) of a large tertiary-care hospital in Italy during January 2013 and June 2017.

METHODS

1281 patients who presented with UTI symptoms to the ED, were stratified into four age categories: young adults (18-44 years old;), adults (45-64), the elderly (65-84), and the oldest old (≥ 85). Inclusion criteria were urine collected in ED patients with UTI symptoms and first positive culture from one given patient in a given year.

RESULTS

362 (28.2%) patients had a urine culture with positive result, leading to a total of 459 germs isolated, stratified into four categories: young adults (58 isolates, 12.6%), adults (98, 21.4%), the elderly (174, 37.9%), and the oldest old (129, 28.1%). Escherichia coli represents the 60% of all monomicrobial infections, followed in frequency by Klebsiella pneumoniae (15%), and Enterococcus faecalis (5%). The other 20% of the infections are caused by various germs. The most common association of germs in polymicrobial is E. coli + E. faecalis, accounting for the 28% of all infections. Overall, we found a peak of susceptibility to amoxicillin (AMX) in the oldest old ( 81%), significantly higher compared to young adults (54%), adults (47%) and elderly (35%) (p<0,001). For ciprofloxacin (CIP) there is a greater susceptibility in the young adult (55.5%), but not so marked compared to the other three groups; for fosfomicin (FOS) the susceptibility was greater in the group of adults (60%) compared to young adults, elderly and the oldest old. Also for trimethoprim/ sulfamethoxazole (TMP-SMX) we found greater susceptibility in the adult group (60%), followed by the oldest old (57,6%), young adults (49%) and elderly (47%).

CONCLUSION

Age-related differences in antimicrobial-resistant microorganisms were evident for adults with UTI, and could potentially contribute to the risk of inappropriate empirical therapy in elderly patients. Thus, different empirical antimicrobial regimens should be considered for distinct age groups.

Monitoring of Particle Environmental Pollution and Fungal Isolations During Hospital Building-Work Activities in a Hematology Ward

Building-work activities could cause dust contamination and fungal spores' dissemination. A significant relationship was found between building-work activities and the incidence of invasive aspergillosis, in profoundly immunocompromised patients. Renovation-works activities were carried out by four building sites of the hematology ward in a Teaching Hospital without the interruption of clinical activities. These sites were monitored by environmental sampling to determine the particles and fungi count. Clinical surveillance was made using galactomannan antigen test as a proxy for invasive aspergillosis diagnosis. A definitive diagnosis of IA was confirmed by clinical and radiological features. The galactomannan antigen test showed no significant difference between presence (2,75%) and absence (5,03%) of renovation work activities (p=0,522). During the renovation activities, an increment of IA cases with respect to the control period was not recorded. The particle counts showed higher values of small and big-diameter particles before the renovation works if compared to the end of the activities. It was probably due to the containment measures implemented during and immediately after the final phases of the building site. The Fungi counts showed no significant differences between the phase before and after the renovation activities. Our findings show that is possible to perform renovation work, during clinical activities, by increasing clinical and environmental surveillance.

In vitro synergism of colistin in combination with N-acetylcysteine against Acinetobacter baumannii grown in planktonic phase and in biofilms

Objectives

To investigate the potential synergism of colistin in combination with N-acetylcysteine against Acinetobacter baumannii strains grown in planktonic phase or as biofilms.

Methods

Sixteen strains were investigated, including nine colistin-susceptible (MIC range 0.5–1 mg/L) and seven colistin-resistant (MIC range 16–256 mg/L) strains. Synergism of colistin in combination with N-acetylcysteine was investigated by chequerboard assays. The activity of colistin/N-acetylcysteine combinations was further evaluated by time–kill assays with planktonic cultures (three colistin-resistant strains and one colistin-susceptible strain) and by in vitro biofilm models (three colistin-resistant and three colistin-susceptible strains).

Results

Chequerboard assays revealed a relevant synergism of colistin/N-acetylcysteine combinations with all colistin-resistant strains, whereas no synergism was observed with colistin-susceptible strains. Time–kill assays showed a concentration-dependent potentiation of colistin activity by N-acetylcysteine against colistin-resistant strains, with eradication of the culture by combinations of N-acetylcysteine at 8000 mg/L plus colistin at 2 or 8 mg/L. A static effect during the first 8 h of incubation was demonstrated with the colistin-susceptible strain exposed to 0.25 × MIC colistin plus 8000 mg/L N-acetylcysteine. A remarkable antibiofilm synergistic activity of 8 mg/L colistin plus 8000 mg/L N-acetylcysteine was demonstrated with all colistin-resistant and colistin-susceptible strains. The effects were greater with colistin-resistant strains (marked reduction of viable biofilm cells was observed at sub-MIC colistin concentrations).

Conclusions

N-acetylcysteine, at concentrations achievable by topical administration, was shown to revert the colistin-resistant phenotype in A. baumannii, and to exert a relevant activity against biofilms of colistin-susceptible and colistin-resistant A. baumannii strains.

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.

Direct use of eazyplex® SuperBug CRE assay from positive blood cultures in conjunction with inpatient infectious disease consulting for timely appropriate antimicrobial therapy in Escherichia coli and Klebsiella pneumoniae bloodstream infections

Objectives: To describe a rapid workflow based on the direct detection of Escherichia coli (Ec) and Klebsiella pneumoniae (Kp) producing CTX-M extended-spectrum β-lactamase (ESBL) and/or carbapenemases (eg, KPC, VIM) from blood cultures (BCs) and the infectious disease (ID) consulting for timely appropriate antimicrobial therapy. Methods: This observational, retrospective study included adult patients with a first episode of Ec or Kp bloodstream infection (BSI) in a large Italian university hospital, where an inpatient ID consultation team (IDCT) has been operational. Results from the BCs tested for detecting bla _CTX-M, bla _KPC, bla _NDM, bla _OXA-48-like, and bla _VIM genes by the eazyplex^® SuperBug CRE assay in Ec and Kp organisms had been notified for antimicrobial therapy consulting. Results: In 321 BSI episodes studied, we found that 151 (47.0%) of Ec or Kp organisms harbored bla _CTX-M and/or bla _KPC and/or bla _VIM (meantime from BC collection: 18.5 h). Empirical antimicrobial treatment was appropriate in 21.8% (33/151) of BSIs, namely 5.9% (3/51) of BSIs caused by KPC/VIM producers and 30.0% (30/100) of BSIs caused by CTX-M producers. After notification of results, the IDCT modified antimicrobial therapy (mean time from BC collection: 20 h) such that the proportion of appropriate treatments increased to 84.8% (128/151) of BSIs, namely 70.6% (36/51) of BSIs caused by KPC/VIM producers and 92.0% (92/100) of BSIs caused by CTX-M producers. Conclusion: Our study shows that a rapid diagnostic-driven clinical strategy allowed for early prescription of potentially effective antimicrobial therapy in BSIs caused by CTX-M ESBL- and/or KPC/VIM carbapenemase-producing Ec and Kp organisms.

In vitro Evaluation of BACT/ALERT® VIRTUO®, BACT/ALERT 3D®, and BACTEC™ FX Automated Blood Culture Systems for Detection of Microbial Pathogens Using Simulated Human Blood Samples

Blood culture (BC) is still the standard for diagnosing bloodstream infections (BSIs), especially those caused by bacteria and fungi. Infection-complicating sepsis or septic shock often occurs at BSI onset, making necessary to improve the diagnostic yield of positive BCs. Among the BC systems currently available, the BACT/ALERT® VIRTUO® (VIRTUO) system has been developed to shorten time to detection (TTD) of positive BCs. In this study, we assessed TTD for 330 clinically relevant species including 14 Gram-positive, 14 Gram-negative, and 5 yeast isolates in spiked human blood samples that were tested in parallel with VIRTUO BACT/ALERT® 3D (BTA3D) and BACTEC™ FX (BACTEC) systems. We inoculated 30 colony-forming unit (CFU) from each microbial suspension into BACT/ALERT® Plus or BACTEC™ Plus (aerobic/anaerobic or pediatric) BC bottles, and we used two different blood volumes to simulate, respectively, the BCs collected from adult and pediatric patients. Of 2,610 bottles tested, 2,600 (99.6%) signaled positive in the three systems. Only the BACTEC system did not detect Staphylococcus lugdunensis isolates in anaerobic bottles. Among adult simulated cultures, the median TTD was significantly shorter for aerobic/anaerobic bottles incubated in VIRTUO (11.6 h and 10.1 h) compared to bottles incubated in either BTA3D (13.3 and 12.3 h) or BACTEC (13.5 and 12.2 h) system. Among pediatric simulated cultures, the median TTD was significantly shorter for bottles incubated in VIRTUO (11.2 h) compared to bottles incubated in either the BTA3D (13.0 h) or BACTEC (12.5 h) system. Compared to BTA3D and/or BACTEC systems, VIRTUO allowed faster growth detection for most of the 33 microbial species tested. Notable examples were Salmonella spp. (7.4 h by VIRTUO vs. 10.1 h and 9.2 h by either BTA3D or BACTEC) and Streptococcus agalactiae (8.1 h by VIRTUO vs. 10.3 and 9.4 h by either BTA3D or BACTEC). The few notable exceptions included Stenotrophomonas maltophilia and some Candida species. Together, these findings confirm that VIRTUO has greater potential of improving the laboratory detection of bacteremia and fungemia than the progenitor BTA3D or the competitor BACTEC system.

A 72-h intervention for improvement of the rate of optimal antibiotic therapy in patients with bloodstream infections

Antimicrobial stewardship programs are implemented to optimize the use of antibiotics and control the spread of antibiotic resistance. Many antimicrobial stewardship interventions have demonstrated significant efficacy in reducing unnecessary prescriptions of antibiotics, the duration of antimicrobial therapy, and mortality. We evaluated the benefits of a combination of rapid diagnostic tests and an active re-evaluation of antibiotic therapy 72 h after the onset of bloodstream infection (BSI). All patients with BSI from November 2015 to November 2016 in a 1100-bed university hospital in Rome, where an Infectious Disease Consultancy Unit (Unità di Consulenza Infettivologica, UDCI) is available, were re-evaluated at the bedside 72 h after starting antimicrobial therapy and compared to two pre-intervention periods: the UDCI was called by the ward physician for patients with BSI and the UDCI was called directly by the microbiologist immediately after a pathogen was isolated from blood cultures. Recommendations for antibiotic de-escalation or discontinuation significantly increased (54%) from the two pre-intervention periods (32% and 27.2%, p < 0.0001). Appropriate escalation also significantly increased (22.5%) from the pre-intervention periods (8.1% and 8.2%, p < 0.0001). The total duration of antibiotic therapy decreased with intervention (from 21.9 days [standard deviation, SD 15.4] in period 1 to 19.3 days [SD 13.3] in period 2 to 17.7 days in period 3 [SD 11.5]; p = 0.002) and the length of stay was significantly shorter (from 29.7 days [SD 29.3] in period 1 to 26.8 days [SD 24.7] in period 2 to 24.2 days in period 3 [SD 20.7]; p = 0.04) than in the two pre-intervention periods. Mortality was similar among the study periods (31 patients died in period 1 (15.7%), 39 (16.7%) in period 2, and 48 (15.3%) in period 3; p = 0.90). Rapid diagnostic tests and 72 h re-evaluation of empirical therapy for BSI significantly correlated with an improved rate of optimal antibiotic therapy and decreased duration of antibiotic therapy and length of stay.

Trimethoprim-sulfamethoxazole therapy for patients with carbapenemase-producing Klebsiella pneumoniae infections: retrospective single-center case series

OBJECTIVE

The objective of the study was to evaluate the efficacy and tolerability of trimethoprim-sulfamethoxazole (also known as co-trimoxazole, TMPS) to treat Klebsiella pneumoniae (Kp)-K. pneumoniae carbapenemase (KPC) infections.

METHODS

Clinical data of patients with a TMPS-susceptible Kp-KPC infection were collected as a case series.

RESULTS

We report clinical outcomes and tolerability for 14 patients infected by Kp-KPC strains susceptible to TMPS, including three bloodstream infections. In ten cases (71.4%), TMPS was administered as monotherapy. In all but one case, Kp-KPC infection was cured. In the remaining patient, therapy was discontinued because of an adverse event.

CONCLUSIONS

The use of TMPS to treat TMPS-susceptible Kp-KPC infections seems promising.

Comparison of Mycoplasma IES, Mycofast Revolution and Mycoplasma IST2 to detect genital mycoplasmas in clinical samples

INTRODUCTION

Culture is regarded as the gold standard for the detection of genital mycoplasma in clinical samples. Commercially available diagnostic kits, based on liquid broth cultures, provide interesting alternatives to conventional culture. We assessed the laboratory performances of Mycoplasma IES (IES), the Mycofast Revolution (REV) and Mycoplasma IST 2 (IST2) compared to A7 agar plates for the detection of Ureaplasma urealyticum and Mycoplasma hominis in clinical samples.

METHODOLOGY

From April to July 2013, endocervical or vaginal samples were collected from sexually active women with abnormal vaginal discharge. Each specimen was tested in parallel using the three commercial kits and the A7 agar plates.

RESULTS

A total of 303 samples were included in this study, 35.6% (108/303) of which were positive on A7 plates. Sensitivities for the detection of U. urealyticum of IES, REV and IST2 were 100%, 96.2% and 95.3%, respectively while those for M. hominis were of 92.8%, 92.8% and 85.7%, respectively. Specificity was 100% for the 3 methods. Concerning antimicrobial susceptibility testing, full agreement between IES and REV was documented.

CONCLUSIONS

The Mycoplasma IES kit was found to be equivalent or superior compared to other commercial culture-based assays for a rapid and accurate identification of U. urealyticum and M. hominis and detection of resistance. It might be considered a cost-effective tool for detection of these organisms, particularly attractive in developing countries.

Catheter-related bacteremia by Cupriavidus metallidurans

Cupriavidus bacteremia is a rare infection and identification of the pathogen is difficult. We present four cases of bacteremia by Cupriavidus metallidurans that were initially identified to the genus level by both Bruker and Vitek matrix-assisted laser desorption ionization-time of flight mass spectrometry and later identified to the species level by 16S rRNA gene sequencing. To our knowledge, these are the first cases of C. metallidurans catheter-related infections. Patients were successfully treated with antibiotic therapy and catheter removal.

Application of MALDI-TOF mass spectrometry in clinical diagnostic microbiology

Matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) has recently emerged as a powerful technique for identification of microorganisms, changing the workflow of well-established laboratories so that its impact on microbiological diagnostics has been unparalleled. In comparison with conventional identification methods that rely on biochemical tests and require long incubation procedures, MALDI-TOF MS has the advantage of identifying bacteria and fungi directly from colonies grown on culture plates in a few minutes and with simple procedures. Numerous studies on different systems available demonstrate the reliability and accuracy of the method, and new frontiers have been explored besides microbial species level identification, such as direct identification of pathogens from positive blood cultures, subtyping, and drug susceptibility detection.

Surveillance of bacterial and fungal infections in the postoperative period following liver transplantation: a series from 2005-2011

Orthotopic liver transplantation (OLT) is a life-saving procedure for the treatment of many end-stage diseases, but infectious and acute rejection episodes remain major causes of morbidity and mortality. Bacterial and fungal infections can be due to intra-abdominal, biliary, respiratory, urinary, wound, central venous catheters (CVC) or unknown sources. Using the computerized database of our microbiology laboratory, we analyzed all the bacterial and fungal infections in the first three months following OLT among 151 consecutive adult recipients at single center between January 2005 and December 2011. Samples included blood, bile CVC, urine, and bronchoalveolar lavage (BAL) specimen. Culture and identification of the isolated microorganisms was done in accordance with standard microbiological procedures. Three hundred thirteen samples from the above sites showed positive results for gram-positive cocci (n = 137; 43.8%), gram-negative rods (n = 156; 49.8%), and Candida species (n = 19; 6.1%). One patient (0.3%) experienced a CVC-related infection caused by Fusarium oxysporum. Bacterial and particularly biliary tract infections seem to play major roles in morbidity and mortality in the first three months following OLT. The major contributors to patient morbidity and mortality were candidemia and/or invasive candidiasis mainly from the biliary tract and/or CVC-related infections.

Risk factors and outcomes of candidemia caused by biofilm-forming isolates in a tertiary care hospital

Background

Very few data exist on risk factors for developing biofilm-forming Candida bloodstream infection (CBSI) or on variables associated with the outcome of patients treated for this infection.

Methods and Findings

We identified 207 patients with CBSI, from whom 84 biofilm-forming and 123 non biofilm-forming Candida isolates were recovered. A case-case-control study to identify risk factors and a cohort study to analyze outcomes were conducted. In addition, two sub-groups of case patients were analyzed after matching for age, sex, APACHE III score, and receipt of adequate antifungal therapy. Independent predictors of biofilm-forming CBSI were presence of central venous catheter (odds ratio [OR], 6.44; 95% confidence interval [95% CI], 3.21–12.92) or urinary catheter (OR, 2.40; 95% CI, 1.18–4.91), use of total parenteral nutrition (OR, 5.21; 95% CI, 2.59–10.48), and diabetes mellitus (OR, 4.47; 95% CI, 2.03–9.83). Hospital mortality, post-CBSI hospital length of stay (LOS) (calculated only among survivors), and costs of antifungal therapy were significantly greater among patients infected by biofilm-forming isolates than those infected by non-biofilm-forming isolates. Among biofilm-forming CBSI patients receiving adequate antifungal therapy, those treated with highly active anti-biofilm (HAAB) agents (e.g., caspofungin) had significantly shorter post-CBSI hospital LOS than those treated with non-HAAB antifungal agents (e.g., fluconazole); this difference was confirmed when this analysis was conducted only among survivors. After matching, all the outcomes were still favorable for patients with non-biofilm-forming CBSI. Furthermore, the biofilm-forming CBSI was significantly associated with a matched excess risk for hospital death of 1.77 compared to non-biofilm-forming CBSI.

Conclusions

Our data show that biofilm growth by Candida has an adverse impact on clinical and economic outcomes of CBSI. Of note, better outcomes were seen for those CBSI patients who received HAAB antifungal therapy.

Intestinal parasites isolated in a large teaching hospital, Italy, 1 May 2006 to 31 December 2008

Intestinal parasites account for the majority of parasitic diseases, particularly in endemic areas. Most are transmitted via contaminated food. Because of increased immigration and travel, enteric parasitoses are now distributed worldwide. Between May 2006 and December 2008, we examined stool specimens from 5,351 patients (4,695 Italians, 656 non-Italians) for ova and parasites using microscopy, culture techniques, and molecular methods. Stools from 594 patients (11.1%) were contaminated and for all patients samples combined, a total of 700 intestinal parasites were counted. Ninety of the 594 infected patients had more than one parasite in their stools. Parasites causing intestinal disease occurred in 8.8% of patients. The prevalence was over twice as high among non-Italians (26.8% vs 8.9% in Italians, p<0.001) and higher in males (13.0% vs 9.5% in females, p=0.003). Most isolates were pathogenic protozoa, including in decreasing order of frequency: Blastocystis hominis, Giardia intestinalis, Entamoeba histolytica, and Cyclospora cayetanensis. The latter two species tended to be more common in Italians, although not at significant level (3.6% (15/418) vs 1.7% (3/176) in non-Italians, OR: 2.15; 95%CI: 0.60–11.70, p=0.22). Helminthes were found in 28 patients, mainly non-Italians (5.7% (10/176) vs 4.3% (18/418), OR: 1.34; 95%CI: 0.54–3.13, p=0.47). Ascaris lumbricoides and Hymenolepis nana were the most common. Strongyloides stercoralis, Enterobius vermicularis, Taenia spp. and Trichuris trichiura were also found. Intestinal parasites are a serious problem in developing countries, but should not be underestimated in industrialised countries.

Evaluation of matrix-assisted laser desorption ionization-time-of-flight mass spectrometry in comparison to rpoB gene sequencing for species identification of bloodstream infection staphylococcal isolates

As a result of variable expression of biochemical characters, misidentification by conventional phenotypic means often occurs with clinical isolates belonging to Staphylococcus species. Therefore, we evaluated the use of matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS) for the identification of 450 blood isolates of the most relevant staphylococcal species, using sequence analysis of the rpoB gene as the reference method. A correct species identification by MALDI-TOF was obtained in 99.3% (447/450), with only three isolates being misidentified. In addition, MALDI-TOF correctly identified all the staphylococcal subspecies studied, including Staphylococcus capitis subsp. capitis and subsp. urealyticus, Staphylococcus cohnii subsp. urealyticus, Staphylococcus hominis subsp. novobiosepticus and subsp. hominis, Staphylococcus saprophyticus subsp. saprophyticus, Staphylococcus schleiferi subsp. schleiferi and Staphylococcus sciuri subsp. sciuri. Thus, MALDI-TOF MS-based species identification of staphylococci can be routinely achieved without any substantial costs for consumables or the time needed for labour-intensive DNA sequence analysis.

Ventriculitis due to Staphylococcus lugdunensis: two case reports

Introduction

Staphylococcus lugdunensis is an unusually virulent coagulase-negative staphylococcus that has rarely been implicated in central nervous system infections.

Case presentation

Two children hospitalized in the Neurosurgery Unit developed ventriculitis caused by methicillin-resistant Staphylococcus lugdunensis following placement of external ventriculostomy drains. The causative organisms were identified by molecular studies. The patients recovered without significant sequelae after high doses of intrathecal vancomycin.

Conclusion

Distinguishing Staphylococcus lugdunensis from other coagulase-negative staphylococcus species is crucial because it carries a substantial risk for severe central nervous system infections displayed by patients with implanted cerebrospinal fluid devices. Clinicians should not underestimate the importance of the isolation of this species from cerebrospinal fluid specimens.

Biofilm production by Candida species and inadequate antifungal therapy as predictors of mortality for patients with candidemia

Nosocomial Candida bloodstream infections rank among infections with highest mortality rates. A retrospective cohort analysis was conducted at Catholic University Hospital to estimate the risk factors for mortality of patients with candidemia. We reviewed records for patients with a Candida bloodstream infection over a 5-year period (January 2000 through December 2004). Two hundred ninety-four patients (42.1% male; mean age +/- standard deviation, 65 +/- 12 years) were studied. Patients most commonly were admitted with a surgical diagnosis (162 patients [55.1%]), had a central venous catheter (213 [72.4%]), cancer (118 [40.1%]), or diabetes (58 [19.7%]). One hundred fifty-four (52.3%) patients died within 30 days. Of 294 patients, 168 (57.1%) were infected by Candida albicans, 64 (21.7%) by Candida parapsilosis, 28 (9.5%) by Candida tropicalis, and 26 (8.8%) by Candida glabrata. When fungal isolates were tested for biofilm formation capacity, biofilm production was most commonly observed for isolates of C. tropicalis (20 of 28 patients [71.4%]), followed by C. glabrata (6 of 26 [23.1%]), C. albicans (38 of 168 [22.6%]), and C. parapsilosis (14 of 64 [21.8%]). Multivariable analysis identified inadequate antifungal therapy (odds ratio [OR], 2.35; 95% confidence interval [95% CI], 1.09 to 5.10; P = 0.03), infection with overall biofilm-forming Candida species (OR, 2.33; 95% CI, 1.26 to 4.30; P = 0.007), and Acute Physiology and Chronic Health Evaluation III scores (OR, 1.03; 95% CI, 1.01 to 1.15; P < 0.001) as independent predictors of mortality. Notably, if mortality was analyzed according to the different biofilm-forming Candida species studied, only infections caused by C. albicans (P < 0.001) and C. parapsilosis (P = 0.003) correlated with increased mortality. Together with well-established factors, Candida biofilm production was therefore shown to be associated with greater mortality of patients with candidemia, probably by preventing complete organism eradication from the blood.

Predictors of mortality in patients with bloodstream infections caused by extended-spectrum-beta-lactamase-producing Enterobacteriaceae: importance of inadequate initial antimicrobial treatment

Bloodstream infections (BSI) caused by extended-spectrum beta-lactamase (ESBL)-producing organisms markedly increase the rates of treatment failure and death. We conducted a retrospective cohort analysis to identify risk factors for mortality in adult in-patients with BSI caused by ESBL-producing Enterobacteriaceae (ESBL-BSI). Particular attention was focused on defining the impact on the mortality of inadequate initial antimicrobial therapy (defined as the initiation of treatment with active antimicrobial agents >72 h after collection of the first positive blood culture). A total of 186 patients with ESBL-BSI caused by Escherichia coli (n = 104), Klebsiella pneumoniae (n = 58), or Proteus mirabilis (n = 24) were identified by our microbiology laboratory from 1 January 1999 through 31 December 2004. The overall 21-day mortality rate was 38.2% (71 of 186). In multivariate analysis, significant predictors of mortality were inadequate initial antimicrobial therapy (odds ratio [OR] = 6.28; 95% confidence interval [CI] = 3.18 to 12.42; P < 0.001) and unidentified primary infection site (OR = 2.69; 95% CI = 1.38 to 5.27; P = 0.004). The inadequately treated patients (89 of 186 [47.8%]) had a threefold increase in mortality compared to the adequately treated group (59.5% versus 18.5%; OR = 2.38; 95% CI = 1.76 to 3.22; P < 0.001). The regimens most commonly classified as inadequate were based on oxyimino cephalosporin or fluoroquinolone therapy. Prompt initiation of effective antimicrobial treatment is essential in patients with ESBL-BSI, and empirical decisions must be based on a sound knowledge of the local distribution of pathogens and their susceptibility patterns.

Evaluation of the new VITEK 2 extended-spectrum beta-lactamase (ESBL) test for rapid detection of ESBL production in Enterobacteriaceae isolates

Extended-spectrum beta-lactamases (ESBLs) are a large, rapidly evolving group of enzymes that confer resistance to oxyimino cephalosporins and monobactams and are inhibited by clavulanate. Rapid reliable detection of ESBL production is a prerequisite for successful infection management and for monitoring resistance trends and implementation of intervention strategies. We evaluated the performance of the new VITEK 2 ESBL test system (bioMérieux, Inc, Hazelwood, Mo.) in the identification of ESBL-producing Enterobacteriaceae isolates. We examined a total of 1,129 clinically relevant Enterobacteriaceae isolates (including 218 that had been previously characterized). The ESBL classification furnished by the VITEK 2 ESBL test system was concordant with that of the comparison method (molecular identification of beta-lactamase genes) for 1,121 (99.3%) of the 1,129 isolates evaluated. ESBL production was correctly detected in 306 of the 312 ESBL-producing organisms (sensitivity, 98.1%; positive predictive value, 99.3%). False-positive results emerged for 2 of the 817 ESBL-negative isolates (specificity, 99.7%; negative predictive value, 99.3%). VITEK 2 ESBL testing took 6 to 13 h (median, 7.5 h; mean +/- SD, 8.2 +/- 2.39 h). This automated short-incubation system appears to be a rapid and reliable tool for routine identification of ESBL-producing isolates of Enterobacteriaceae.

Caspofungin activity against clinical isolates of azole cross-resistant Candida glabrata overexpressing efflux pump genes

OBJECTIVES

Several studies have documented the potent in vitro activity of caspofungin against Candida spp. This is of special concern for Candida glabrata infections that are often resistant to many azole antifungal agents and, consequently, difficult to treat. The aim of the present study was to expand the data on the in vitro activity of caspofungin against azole-resistant isolates of C. glabrata.

METHODS

A total of 50 clinical isolates of C. glabrata were tested for susceptibility to caspofungin. The isolates were cross-resistant to multiple azoles, including fluconazole, itraconazole, ketoconazole and voriconazole. Expression of the resistance-related CgCDR1 and CgCDR2 genes was evaluated by quantitative RT-PCR analysis. The MICs of caspofungin were determined by using the National Committee for Clinical Laboratory Standards M27-A2 reference method.

RESULTS

C. glabrata isolates exhibited increased expression of the CDR efflux pump(s), and this was in accordance with their high-level azole resistance. In contrast, all the isolates were highly susceptible to caspofungin (100% of isolates were inhibited at <or=1 mg/L).

CONCLUSIONS

Our results represent further evidence for the excellent antifungal potency of caspofungin, particularly against C. glabrata isolates expressing cross-resistance to azoles.

Role of AFR1, an ABC transporter-encoding gene, in the in vivo response to fluconazole and virulence of Cryptococcus neoformans

We have recently demonstrated that upregulation of the ATP binding cassette (ABC) transporter-encoding gene AFR1 in Cryptococcus neoformans is involved in the in vitro resistance to fluconazole of this yeast. In the present study, we investigated the role of AFR1 in the in vivo response to fluconazole in a mouse model of systemic cryptococcosis. Mice were infected with a wild-type fluconazole-susceptible strain of C. neoformans, strain BPY22; an afr1 mutant, BPY444, which displayed hypersusceptibility to fluconazole in vitro; or an AFR1-overexpressing strain, BPY445, which exhibited in vitro resistance to the drug. In each of the three groups, infected animals were randomly assigned to fluconazole treatment or untreated-control subgroups. As expected, fluconazole prolonged survival and reduced fungal tissue burdens (compared with no treatment) in BPY22- and BPY444-infected mice, whereas it had no significant effects in mice infected with BPY445. When the pathogenicities of these strains in mice were investigated, strain BPY445 was significantly more virulent than BPY22 following inhalational or intravenous inoculation, but mice infected with BPY444 survived significantly longer than BPY22-infected animals only when infection was acquired via the respiratory tract. In in vitro macrophage infection studies, strain BPY445 also displayed enhanced intracellular survival compared with strains BPY22 and BPY444, suggesting that its increased virulence may be due to its reduced vulnerability to the antimicrobial factors produced by phagocytic cells. These findings indicate that the upregulation of the AFR1 gene is an important factor in either determining the in vivo resistance to fluconazole or influencing the virulence of C. neoformans.