Bacterial/fungal infection in hospitalized patients with COVID-19 in a tertiary hospital in the Community of Castilla y León, Spain

Emerging Antimicrobial Resistance

The burden of emerging antimicrobial resistance (AMR) in the United States is significant and even greater worldwide. Mitigation efforts have decreased the incidence and deaths from antimicrobial-resistant organisms in the United States. Yet more than 2.8 million antimicrobial-resistant infections occur every year and more than 35,000 patients die as a result. Infection prevention and control, data tracking, antimicrobial stewardship, vaccines, therapeutics, diagnostics, and sanitation are all required to decrease AMR threats. In 2019, in the second version of the Centers for Disease Control and Prevention (CDC) report on antibiotic-resistant threats, the agency categorized AMR threats as urgent, serious, concerning, or to be watched. This review will discuss the following aspects of each bacterium in the CDC report: estimated numbers of cases and deaths, identify the better known and impactful mechanisms of resistance, diagnostic testing and its limitations, and current and possible future therapies. This review also presents anatomical pathology case examples that highlight the altered morphology of antibiotic partially treated bacteria in tissues.

Ventilator-associated pneumonia (VAP) and pleural empyema caused by multidrug-resistant Acinetobacter baumannii in HIV and COVID 19 infected patient: A case report

We analyzed the case of a 49-year-old woman with HIV infection off-therapy with poor viro-immunological compensation, not vaccinated for SARS-COV-2, hospitalized for lobar pneumonia and severe COVID19-related respiratory failure in intensive care unit (ICU). The hospitalization was complicated by bacteraemic ventilator-associated pneumonia (VAP) caused by multidrug-resistant Acinetobacter baumannii (MDR-AB) isolated on pleural fluid culture, treated with colistin and cefiderocol for about 3 weeks. The molecular research of MDR-AB on transtracheal aspirate was negative following this therapy. The aim is to show the safety, efficacy and tolerability of colistin-based combination therapy with cefiderocol for Acinetobacter baumannii infection in HIV-infected patient.

Epidemiology of bacterial co-infections and risk factors in COVID-19-hospitalized patients in Spain: a nationwide study

BACKGROUND

We performed a nationwide population-based retrospective study to describe the epidemiology of bacterial co-infections in coronavirus disease 2019 (COVID-19)-hospitalized patients in Spain in 2020. We also analyzed the risk factors for co-infection, the etiology and the impact in the outcome.

METHODS

Data were obtained from records in the Minimum Basic Data Set (MBDS) of the National Surveillance System for Hospital Data in Spain, provided by the Ministry of Health and annually published with 2 years lag. COVID-19 circulated in two waves in 2020: from its introduction to 31st June and from 1st July to 31st December. The risk of developing a healthcare-associated bacterial co-infection and the risk for in-hospital and intensive care unit (ICU) mortality in co-infected patients was assessed using an adjusted logistic regression model.

RESULTS

The incidence of bacterial co-infection in COVID-19 hospitalized patients was 2.3%. The main risk factors associated with bacterial co-infection were organ failure, obesity and male sex. Co-infection was associated with worse outcomes including higher in-hospital, in-ICU mortality and higher length of stay. Gram-negative bacteria caused most infections. Causative agents were similar between waves, although higher co-infections with Pseudomonas spp. were detected in the first wave and with Haemophilus influenzae and Streptococcus pneumoniae in the second.

CONCLUSIONS

Co-infections are not as common as those found in other viral respiratory infections; therefore, antibiotics should be used carefully. Screening for actual co-infection to prescribe antibiotic therapy when required should be performed.

Antimicrobial resistance in patients with COVID-19: a systematic review and meta-analysis

BACKGROUND

Frequent use of antibiotics in patients with COVID-19 threatens to exacerbate antimicrobial resistance. We aimed to establish the prevalence and predictors of bacterial infections and antimicrobial resistance in patients with COVID-19.

METHODS

We did a systematic review and meta-analysis of studies of bacterial co-infections (identified within ≤48 h of presentation) and secondary infections (>48 h after presentation) in outpatients or hospitalised patients with COVID-19. We searched the WHO COVID-19 Research Database to identify cohort studies, case series, case-control trials, and randomised controlled trials with populations of at least 50 patients published in any language between Jan 1, 2019, and Dec 1, 2021. Reviews, editorials, letters, pre-prints, and conference proceedings were excluded, as were studies in which bacterial infection was not microbiologically confirmed (or confirmed via nasopharyngeal swab only). We screened titles and abstracts of papers identified by our search, and then assessed the full text of potentially relevant articles. We reported the pooled prevalence of bacterial infections and antimicrobial resistance by doing a random-effects meta-analysis and meta-regression. Our primary outcomes were the prevalence of bacterial co-infection and secondary infection, and the prevalence of antibiotic-resistant pathogens among patients with laboratory-confirmed COVID-19 and bacterial infections. The study protocol was registered with PROSPERO (CRD42021297344).

FINDINGS

We included 148 studies of 362  976 patients, which were done between December, 2019, and May, 2021. The prevalence of bacterial co-infection was 5·3% (95% CI 3·8-7·4), whereas the prevalence of secondary bacterial infection was 18·4% (14·0-23·7). 42 (28%) studies included comprehensive data for the prevalence of antimicrobial resistance among bacterial infections. Among people with bacterial infections, the proportion of infections that were resistant to antimicrobials was 60·8% (95% CI 38·6-79·3), and the proportion of isolates that were resistant was 37·5% (26·9-49·5). Heterogeneity in the reported prevalence of antimicrobial resistance in organisms was substantial (I2=95%).

INTERPRETATION

Although infrequently assessed, antimicrobial resistance is highly prevalent in patients with COVID-19 and bacterial infections. Future research and surveillance assessing the effect of COVID-19 on antimicrobial resistance at the patient and population level are urgently needed.

FUNDING

WHO.

The application of targeted nanopore sequencing for the identification of pathogens and resistance genes in lower respiratory tract infections

Objectives

Lower respiratory tract infections (LRTIs) are one of the causes of mortality among infectious diseases. Microbial cultures commonly used in clinical practice are time-consuming, have poor sensitivity to unculturable and polymicrobial patterns, and are inadequate to guide timely and accurate antibiotic therapy. We investigated the feasibility of targeted nanopore sequencing (TNPseq) for the identification of pathogen and antimicrobial resistance (AMR) genes across suspected patients with LRTIs. TNPseq is a novel approach, which was improved based on nanopore sequencing for the identification of bacterial and fungal infections of clinical relevance.

Methods

This prospective study recruited 146 patients suspected of having LRTIs and with a median age of 61 years. The potential pathogens in these patients were detected by both TNPseq and the traditional culture workups. We compared the performance between the two methods among 146 LRTIs-related specimens. AMR genes were also detected by TNPseq to prompt the proper utilization of antibiotics.

Results

At least one pathogen was detected in 133 (91.1%) samples by TNPseq, but only 37 (25.3%) samples contained positive isolates among 146 cultured specimens. TNPseq possessed higher sensitivity than the conventional culture method (91.1 vs. 25.3%, P < 0.001) in identifying pathogens. It detected more samples with bacterial infections (P < 0.001) and mixed infections (P < 0.001) compared with the clinical culture tests. The most frequent AMR gene identified by TNPseq was bla _TEM (n = 29), followed by bla _SHV (n = 4), bla _KPC (n = 2), bla _CTX-M (n = 2), and mecA (n = 2). Furthermore, TNPseq discovered five possible multi-drug resistance specimens.

Conclusion

TNPseq is efficient to identify pathogens early, thus assisting physicians to conduct timely and precise treatment for patients with suspected LRTIs.

Secondary Infections in Critically Ill Patients with COVID-19: A Retrospective Study

Patients with severe COVID-19, especially those followed in the ICU, are at risk for developing bacterial and fungal superinfections. In this study, we aimed to describe the burden of hospital-acquired superinfections in a cohort of consecutive, severe COVID-19 patients hospitalized between February and May 2021 in the intensive care unit (ICU) department of San Salvatore Hospital in Pesaro, Italy. Among 89 patients considered, 68 (76.4%) acquired a secondary infection during their ICU stay. A total of 46 cases of ventilator-associated pneumonia (VAP), 31 bloodstream infections (BSIs) and 15 catheter-associated urinary tract infections (CAUTIs) were diagnosed. Overall mortality during ICU stay was 48%. A multivariate analysis showed that factors independently associated with mortality were male gender (OR: 4.875, CI: 1.227–19.366, p = 0.024), higher BMI (OR: 4.938, CI:1.356–17.980, p = 0.015) and the presence of VAP (OR: 6.518, CI: 2.178–19.510, p = 0.001). Gram-negative bacteria accounted for most of the isolates (68.8%), followed by Gram-positive bacteria (25.8%) and fungi (5.3%). Over half of the infections (58%) were caused by MDR opportunistic pathogens. Factors that were independently associated with an increased risk of infections caused by an MDR pathogen were higher BMI (OR: 4.378, CI: 1.467–13.064, p = 0.0008) and a higher Charlson Comorbidity Index (OR: 3.451, 95% CI: 1.113–10.700, p = 0.032). Secondary infections represent a common and life-threatening complication in critically ill patients with COVID-19. Efforts to minimize the likelihood of acquiring such infections, often caused by difficult-to-treat MDR organisms—especially in some subgroups of patients with specific risk factors—must be pursued.

Profile of Co-Infection Prevalence and Antibiotics Use among COVID-19 Patients

Bacterial co-infection in COVID-19 patients significantly contributes to the worsening of the prognosis based on morbidity and mortality. Information on the co-infection profile in such patients could help to optimize treatment. The purpose of this study was to describe bacterial co-infections associated with microbiological, clinical, and laboratory data to reduce or avoid a secondary infection. A retrospective cohort study was conducted at Sant'Anna and San Sebastiano Hospital from January 2020 to December 2021. Bacterial co-infection was detected in 14.3% of the COVID-19-positive patients. The laboratory findings on admission showed significant alterations in the median D-dimer, C-reactive protein, interleukin-6, and lactate dehydrogenase values compared to normal values. All inflammatory markers were significantly elevated. The most common pathogens isolated from blood cultures were E. faecalis and S. aureus. Instead, the high prevalence of respiratory tract infections in the COVID-19 patients was caused by P. aeruginosa (41%). In our study, 220 (82.4%) of the COVID-19 patients received antimicrobial treatment. Aminoglycosides and β-lactams/β-lactamase inhibitors showed the highest resistance rates. Our results showed that older age, underlying conditions, and abnormal laboratory parameters can be risk factors for co-infection in COVID-19 patients. The antibiotic susceptibility profile of bacterial pathogen infection provides evidence on the importance, for the clinicians, to rationalize and individualize antibiotic usage.

Clinical Impact of COVID-19 on Multi-Drug-Resistant Gram-Negative Bacilli Bloodstream Infections in an Intensive Care Unit Setting: Two Pandemics Compared

Two mutually related pandemics are ongoing worldwide: the COVID-19 and antimicrobial resistance pandemics. This study aims to evaluate the impact of COVID-19 on multi-drug-resistant Gram-negative bacteria (MDR-GN) bloodstream infections (BSIs) in a single intensive care unit (ICU). We conducted a retrospective study including patients admitted to the ICU, reorganized for COVID-19 patients’ healthcare, with at least one confirmed MDR-GN BSI during 2019–2020. We compared clinical and microbiological features, incidence density, antibiotic therapy and mortality rate in pre- and during-COVID-19 pandemic periods. We estimated the impact of COVID-19 on mortality by means of univariate Cox regression analyses. A total of 46 patients were included in the study (28 non-COVID-19/18 COVID-19). Overall, 63 BSI episodes occurred (44/19), and non-COVID-19 patients had a higher incidence of MDR-GN BSIs and were more likely to present K. pneumoniae BSIs, while the COVID-19 group showed more A. baumannii BSIs with higher per pathogen incidence. COVID-19 patients presented more critical conditions at the BSI onset, a shorter hospitalization time from BSI to death and higher 30-day mortality rate from BSI onset. COVID-19 and septic shock were associated with 30-day mortality from MDR-GN BSIs, while early active therapy was a protective factor. In conclusion, COVID-19 showed a negative impact on patients with MDR-GN BSIs admitted to the ICU.

Bloodstream Infections in a COVID-19 Non-ICU Department: Microbial Epidemiology, Resistance Profiles and Comparative Analysis of Risk Factors and Patients' Outcome

Background: Bloodstream infections (BSI) caused by highly resistant pathogens in non-ICU COVID-19 departments pose important challenges. Methods: We performed a comparative analysis of incidence and microbial epidemiology of BSI in COVID-19 vs. non-COVID-19, non-ICU departments between 1 September 2020-31 October 2021. Risk factors for BSI and its impact on outcome were evaluated by a case-control study which included COVID-19 patients with/without BSI. Results: Forty out of 1985 COVID-19 patients developed BSI. The mean monthly incidence/100 admissions was 2.015 in COVID-19 and 1.742 in non-COVID-19 departments. Enterococcus and Candida isolates predominated in the COVID-19 group (p < 0.001 and p = 0.018, respectively). All Acinetobacter baumannii isolates were carbapenem-resistant (CR). In the COVID-19 group, 33.3% of Klebsiella pneumoniae was CR, 50% of Escherichia coli produced ESBL and 19% of Enterococcus spp. were VRE vs. 74.5%, 26.1% and 8.8% in the non-COVID-19 group, respectively. BSI was associated with prior hospitalization (p = 0.003), >2 comorbidities (p < 0.001), central venous catheter (p = 0.015), severe SARS-CoV-2 pneumonia and lack of COVID-19 vaccination (p < 0.001). In the multivariate regression model also including age and multiple comorbidities, only BSI was significantly associated with adverse in-hospital outcome [OR (CI95%): 21.47 (3.86−119.21), p < 0.001]. Conclusions: BSI complicates unvaccinated patients with severe SARS-CoV-2 pneumonia and increases mortality. BSI pathogens and resistance profiles differ among COVID-19/non-COVID-19 departments, suggesting various routes of pathogen acquisition.

Fungal Bloodstream Co-infection by Trichosporon asahii in a COVID-19 Critical Patient: Case Report and Literature Review

Opportunistic infections are serious complications in critically ill COVID-19 patients, especially co-infections with bacterial and fungal agents. Here we report a rare case of bloodstream co-infection by Trichosporon asahii, an emerging yeast, and Acinetobacterbaumannii, an opportunistic nosocomial pathogen, both multidrug resistant, in a tertiary hospital from southern Brazil. A review of the literature regarding similar cases is also included. Treatment with multiple antimicrobials failed, and the patient progressed to death four days after the diagnosis of bacteremia and fungemia.

Cefiderocol for Severe Carbapenem-Resistant A. baumannii Pneumonia: Towards the Comprehension of Its Place in Therapy

Cefiderocol use in A. baumannii pneumonia still represents an important matter of debate. The aim of this study is to describe 13 cases of carbapenem-resistant A. baumannii (CRAB) pneumonia treated with cefiderocol in real-life practice. We retrospectively included patients with CRAB pneumonia hospitalized at Fondazione Policlinico Universitario Agostino Gemelli Hospital treated with cefiderocol either in the general ward or the intensive care unit. A total of 11 patients out of 13 had ventilator-associated pneumonia caused by CRAB, and 12/13 patients had polymicrobial infection. We found a 30-day success rate of 54%. Cefiderocol may have a role when facing severe XDR A. baumannii pneumonia. Future studies are warranted to better define its place in therapy in CRAB infections.

A Visual and Comprehensive Review on COVID-19-Associated Pulmonary Aspergillosis (CAPA)

Coronavirus disease 19 (COVID-19)-associated pulmonary aspergillosis (CAPA) is a severe fungal infection complicating critically ill COVID-19 patients. Numerous retrospective and prospective studies have been performed to get a better grasp on this lethal co-infection. We performed a qualitative review and summarized data from 48 studies in which 7047 patients had been included, of whom 820 had CAPA. The pooled incidence of proven, probable or putative CAPA was 15.1% among 2953 ICU-admitted COVID-19 patients included in 18 prospective studies. Incidences showed great variability due to multiple factors such as discrepancies in the rate and depth of the fungal work-up. The pathophysiology and risk factors for CAPA are ill-defined, but therapy with corticosteroids and anti-interleukin-6 therapy potentially confer the biggest risk. Sampling for mycological work-up using bronchoscopy is the cornerstone for diagnosis, as imaging is often aspecific. CAPA is associated with an increased mortality, but we do not have conclusive data whether therapy contributes to an increased survival in these patients. We conclude our review with a comparison between influenza-associated pulmonary aspergillosis (IAPA) and CAPA.

Invasive Fungal Infections Complicating COVID-19: A Narrative Review

Invasive fungal infections (IFIs) can complicate the clinical course of COVID-19 and are associated with a significant increase in mortality, especially in critically ill patients admitted to an intensive care unit (ICU). This narrative review concerns 4099 cases of IFIs in 58,784 COVID-19 patients involved in 168 studies. COVID-19-associated invasive pulmonary aspergillosis (CAPA) is a diagnostic challenge because its non-specific clinical/imaging features and the fact that the proposed clinically diagnostic algorithms do not really apply to COVID-19 patients. Forty-seven observational studies and 41 case reports have described a total of 478 CAPA cases that were mainly diagnosed on the basis of cultured respiratory specimens and/or biomarkers/molecular biology, usually without histopathological confirmation. Candidemia is a widely described secondary infection in critically ill patients undergoing prolonged hospitalisation, and the case reports and observational studies of 401 cases indicate high crude mortality rates of 56.1% and 74.8%, respectively. COVID-19 patients are often characterised by the presence of known risk factors for candidemia such as in-dwelling vascular catheters, mechanical ventilation, and broad-spectrum antibiotics. We also describe 3185 cases of mucormycosis (including 1549 cases of rhino-orbital mucormycosis (48.6%)), for which the main risk factor is a history of poorly controlled diabetes mellitus (>76%). Its diagnosis involves a histopathological examination of tissue biopsies, and its treatment requires anti-fungal therapy combined with aggressive surgical resection/debridement, but crude mortality rates are again high: 50.8% in case reports and 16% in observational studies. The presence of other secondary IFIs usually diagnosed in severely immunocompromised patients show that SARS-CoV-2 is capable of stunning the host immune system: 20 cases of Pneumocystis jirovecii pneumonia, 5 cases of cryptococcosis, 4 cases of histoplasmosis, 1 case of coccidioides infection, 1 case of pulmonary infection due to Fusarium spp., and 1 case of pulmonary infection due to Scedosporium.

Impact of SARS-CoV-2 Epidemic on Antimicrobial Resistance: A Literature Review

Antimicrobial resistance is an urgent threat to public health and global development; in this scenario, the SARS-CoV2 pandemic has caused a major disruption of healthcare systems and practices. A narrative review was conducted on articles focusing on the impact of COVID-19 on multidrug-resistant gram-negative, gram-positive bacteria, and fungi. We found that, worldwide, multiple studies reported an unexpected high incidence of infections due to methicillin-resistant S. aureus, carbapenem-resistant A. baumannii, carbapenem-resistant Enterobacteriaceae, and C. auris among COVID-19 patients admitted to the intensive care unit. In this setting, inappropriate antimicrobial exposure, environmental contamination, and discontinuation of infection control measures may have driven selection and diffusion of drug-resistant pathogens.

Acinetobacter baumannii Infections in Times of COVID-19 Pandemic

The COVID-19 pandemic has generated an overuse of antimicrobials in critically ill patients. Acinetobacter baumannii frequently causes nosocomial infections, particularly in intensive care units (ICUs), where the incidence has increased over time. Since the WHO declared the COVID-19 pandemic on 12 March 2020, the disease has spread rapidly, and many of the patients infected with SARS-CoV-2 needed to be admitted to the ICU. Bacterial co-pathogens are commonly identified in viral respiratory infections and are important causes of morbidity and mortality. However, we cannot neglect the increased incidence of antimicrobial resistance, which may be attributed to the excess use of antimicrobial agents during the COVID-19 pandemic. Patients with COVID-19 could be vulnerable to other infections owing to multiple comorbidities with severe COVID-19, prolonged hospitalization, and SARS-CoV-2-associated immune dysfunction. These patients have acquired secondary bacterial infections or superinfections, mainly bacteremia and urinary tract infections. This review will summarize the prevalence of A. baumannii coinfection and secondary infection in patients with COVID-19.

Acinetobacter baumannii Antibiotic Resistance Mechanisms

Acinetobacter baumannii is a Gram-negative ESKAPE microorganism that poses a threat to public health by causing severe and invasive (mostly nosocomial) infections linked with high mortality rates. During the last years, this pathogen displayed multidrug resistance (MDR), mainly due to extensive antibiotic abuse and poor stewardship. MDR isolates are associated with medical history of long hospitalization stays, presence of catheters, and mechanical ventilation, while immunocompromised and severely ill hosts predispose to invasive infections. Next-generation sequencing techniques have revolutionized diagnosis of severe A. baumannii infections, contributing to timely diagnosis and personalized therapeutic regimens according to the identification of the respective resistance genes. The aim of this review is to describe in detail all current knowledge on the genetic background of A. baumannii resistance mechanisms in humans as regards beta-lactams (penicillins, cephalosporins, carbapenems, monobactams, and beta-lactamase inhibitors), aminoglycosides, tetracyclines, fluoroquinolones, macrolides, lincosamides, streptogramin antibiotics, polymyxins, and others (amphenicols, oxazolidinones, rifamycins, fosfomycin, diaminopyrimidines, sulfonamides, glycopeptide, and lipopeptide antibiotics). Mechanisms of antimicrobial resistance refer mainly to regulation of antibiotic transportation through bacterial membranes, alteration of the antibiotic target site, and enzymatic modifications resulting in antibiotic neutralization. Virulence factors that may affect antibiotic susceptibility profiles and confer drug resistance are also being discussed. Reports from cases of A. baumannii coinfection with SARS-CoV-2 during the COVID-19 pandemic in terms of resistance profiles and MDR genes have been investigated.

Evolution of Antimicrobial Consumption During the First Wave of COVID-19 Pandemic

Background: The first wave of COVID-19 pandemic may have significantly impacted antimicrobial consumption in hospitals. The objective of this study was to assess the evolution of antimicrobial consumption during this period. Methods: A retrospective quasi-experimental before–after study was conducted in a Spanish tertiary care hospital. The study compared two periods: pre-pandemic, from January 2018 to February 2020, and during the COVID-19 pandemic from March to June 2020. Antimicrobial consumption was analyzed monthly as defined daily doses (DDD)/100 bed-days and overall hospital and ICU consumption were evaluated. Results: An increase in the hospital consumption was noticed. Although only ceftaroline achieved statistical significance (p = 0.014), a rise was observed in most of the studied antimicrobials. A clear temporal pattern was detected. While an increase in ceftriaxone and azithromycin was observed during March, an increment in the consumption of daptomycin, carbapenems, linezolid, ceftaroline, novel cephalosporin/β-lactamase inhibitors or triazoles during April–May was noticed. In the ICU, these findings were more evident, namely ceftriaxone (p = 0.029), carbapenems (p = 0.002), daptomycin (p = 0.002), azithromycin (p = 0.030), and linezolid (p = 0.011) but followed a similar temporal pattern. Conclusion: An increase in the antimicrobial consumption during the first wave of COVID-19 pandemic was noticed, especially in the ICU. Availability of updated protocols and antimicrobial stewardship programs are essential to optimize these outcomes.