Long-Term Effects of a Stepwise, Multimodal, Non-Restrictive Antimicrobial Stewardship Programme for Reducing Broad-Spectrum Antibiotic Use in the ICU.

Information on the long-term effects of non-restrictive antimicrobial stewardship (AMS) strategies is scarce. We assessed the effect of a stepwise, multimodal, non-restrictive AMS programme on broad-spectrum antibiotic use in the intensive care unit (ICU) over an 8-year period. Components of the AMS were progressively implemented. Appropriateness of antibiotic prescribing was also assessed by monthly point-prevalence surveys from 2013 onwards. A Poisson regression model was fitted to evaluate trends in the reduction of antibiotic use and in the appropriateness of their prescription. From 2011 to 2019, a total of 12,466 patients were admitted to the ICU. Antibiotic use fell from 185.4 to 141.9 DDD per 100 PD [absolute difference, -43.5 (23%), 95% CI -100.73 to 13.73; p = 0.13] and broad-spectrum antibiotic fell from 41.2 to 36.5 [absolute difference, -4.7 (11%), 95% CI -19.58 to 10.18; p = 0.5]. Appropriateness of antibiotic prescribing rose by 11% per year [IRR: 0.89, 95% CI 0.80 to 1.00; p = 0.048], while broad-spectrum antibiotic use showed a dual trend, rising by 22% until 2015 and then falling by 10% per year since 2016 [IRR: 0.90, 95% CI 0.81 to 0.99; p = 0.03]. This stepwise, multimodal, non-restrictive AMS achieved a sustained reduction in broad-spectrum antibiotic use in the ICU and significantly improved appropriateness of antibiotic prescribing.

Development of Meropenem Resistance in a Multidrug-Resistant Campylobacter coli Strain Causing Recurrent Bacteremia in a Hematological Malignancy Patient.

Campylobacter bacteremia is an uncommon disease that mainly occurs in immunocompromised patients and is associated with antibiotic resistance, particularly in Campylobacter coli. We report a patient with persistent blood infection because of a multidrug-resistant (MDR) C. coli strain over a 3-month period. Through this period monotherapy with meropenem was associated with the development of resistance to it. Improving immunity status and a combined therapy for intestinal decolonization were useful to control persistent C. coli infection in this patient.

Activity of imipenem/relebactam against Enterobacterales and Pseudomonas aeruginosa in Spain. SMART 2016-2020

Objectives: To determine susceptibility to the novel β-lactam/β-lactamase inhibitor combination imipenem/relebactam in clinical isolates recovered from intra-abdominal (IAI), urinary (UTI), respiratory (RTI) and bloodstream (BSI) infections in the SMART (Study for Monitoring Antimicrobial Resistance Trends) study in SPAIN during 2016 – 2020.Methods: Broth microdilution MICs for imipenem/relebactam and comparators were determined by a central laboratory against isolates of Enterobacterales and Pseudomonas aeruginosa. MICs were interpreted using EUCAST-2021 breakpoints.Results: In total, 5,210 Enterobacterales and 1,418 P. aeruginosa clinical isolates were analyzed. Imipenem/relebactam inhibited 98.8% of Enterobacterales. Distinguishing by source of infection susceptibility was 99.1% in BSI, 99.2% in IAI, 97.9% in RTI, and 99.2% in UTI. Of intensive care unit isolates (ICU) 97.4% were susceptible and of non-ICU isolates 99.2% were susceptible. In Enterobacterales, activity against Class A, Class B and Class D carbapenemases was 96.2%, 15.4% and 73.2%, respectively. In P. aeruginosa, imipenem/relebactam was active in 92.2% of isolates. By source of infection it was 94.8% in BSI, 92.9% in IAI, 91.7% in RTI, and 93.1% in UTI. An 88.7% of ICU isolates and 93.6% of non-ICU isolates were susceptible to imipenem/relebactam. Imipenem/relebactam remained active against P. aeruginosa ceftazidime-resistant (76.3%), cefepime-resistant (73.6%), imipenem-resistant (71.5%) and piperacillin-resistant (78.7%) isolates. Of all multidrug-resistant or difficult-to-treat resistance P. aeruginosa isolates, 75.1% and 46.2%, respectively, were susceptible to imipenem/relebactam. (AU)

Objetivos: Determinar la sensibilidad a la nueva combinación de β-lactámico e inhibidor de β-lactamasas imipenem/relebactam en aislados clínicos procedentes de infecciones intraabdominales (IIA), urinarias (ITU), respiratorias (ITR) y bacteriemias del estudio SMART (Study for Monitoring Antimicrobial Resistance Trends) en ESPAÑA durante 2016 - 2020. Métodos. Se determinó la CMI mediante microdilución en caldo de imipenem/relebactam y antibióticos comparadores frente a aislados de Enterobacterales y Pseudomonas aeruginosa. Las CMI se analizaron empleando los puntos de corte EUCAST-2021. Resultados: En total, se incluyeron 5.210 aislados de Enterobacterales y 1.418 aislados de P. aeruginosa. Imipenem/ relebactam fue activo frente al 98,8% de los Enterobacterales. Distinguiendo por foco de infección, la sensibilidad fue del 99,1% en bacteriemia, del 99,2% en IIA, del 97,9% en ITR y del 99,2% en ITU. El 97,4% de los aislados procedentes de unidades de cuidados intensivos (UCI) fueron sensibles, y el 99,2% de los aislados no procedentes de UCI. En Enterobacterales, la sensibilidad frente a carbapenemasas de clase A, clase B y clase D fue del 96,2%, 15,4% y 73,2%, respectivamente. En P. aeruginosa,imipenem/relebactam fue activo en el 92,2% de los aislados. Distinguiendo por foco de infección, la sensibilidad frente a P. aeruginosa fue del 94,8% en bacteriemia, 92,9% en IIA, 91,7% en ITR y 93,1% en ITU. El 88,7% de los aislados de la UCI y el 93,6% de los aislados no procedentes de UCI fueron sensibles a imipenem/relebactam. Imipenem/relebactam fue activo frente a aislados de P. aeruginosa resistentes a ceftazidima (76,3%), cefepima (73,6%), imipenem (71,5%) y piperacilina/tazobactam (78,7%). Frente a los aislados de P. aeruginosa clasificados como MDR o DTR, el 75,1% y el 46,2%, respectivamente, fueron sensibles a imipenem/relebactam. (AU)

Impact of a prospective audit and feedback antimicrobial stewardship programme on carbapenem consumption: a quasi-experimental study (IPANEMA study).

OBJECTIVES: To test the hypothesis that a prospective audit and feedback (PAF) intervention combined with electronic tools will reduce carbapenem use without negatively affecting patient outcomes. METHODS: A quasi-experimental, pre-intervention and intervention study was performed conducted in the urology department of a university hospital. The intervention involved implementing a PAF within an antimicrobial stewardship programme with the aid of an electronic tool. The primary outcome was carbapenem use, assessed by DDD/100 patient-days (PD). Secondary outcomes included evaluating the effect of the intervention on overall antibiotic use measured by DDD/100 PD and days of therapy (DOT)/100 PD, as well as patient safety. The chi-squared test or t-test was used, and the Poisson model was employed to assess the association between the intervention and outcomes. RESULTS: A 9% decrease in carbapenem DDD/100 PD was observed during the intervention period (IR = 0.91; 95% CI = 0.85-0.97, P = 0.007). The proportion of patients who received carbapenem treatment dropped from 17.8% to 16.5% [incidence ratio (IR) = 0.95; 95% CI = 0.86-2.05, P = 0.31]. Carbapenem DOT/100 PD decreased from 12.4 to 11.0 (IR = 0.89; 95% CI = 0.83-0.94, P < 0.001). Overall antibiotic DDD/100 PD decreased by 3% (IR = 0.97; 95% CI = 0.94-0.99, P = 0.001) and DOT/100 PD by 7% (IR = 0.93; 95% CI = 0.91-0.95, P < 0.001). The incidence of infections caused by carbapenemase-producing microorganisms, Enterococcus faecium bacteraemia and Clostridioides difficile-associated diarrhoea episodes was similar in the pre-intervention and intervention periods. ESBL incidence rate decreased, but the differences were not statistically significant (3.94/1000 PD versus 2.88/1000 PD, P = 0.111). Length of hospital stay, in-hospital all-cause mortality, and 30 day readmission incidence remained unchanged. CONCLUSIONS: The implementation of PAF combined with an electronic tool was an effective and safe intervention for reducing carbapenem use.

Genetic Adaptation and Acquisition of Macrolide Resistance in Haemophilus spp. during Persistent Respiratory Tract Colonization in Chronic Obstructive Pulmonary Disease (COPD) Patients Receiving Long-Term Azithromycin Treatment.

Patients with chronic obstructive pulmonary disease (COPD) benefit from the immunomodulatory effect of azithromycin, but long-term administration may alter colonizing bacteria. Our goal was to identify changes in Haemophilus influenzae and Haemophilus parainfluenzae during azithromycin treatment. Fifteen patients were followed while receiving prolonged azithromycin treatment (Hospital Universitari de Bellvitge, Spain). Four patients (P02, P08, P11, and P13) were persistently colonized by H. influenzae for at least 3 months and two (P04 and P11) by H. parainfluenzae. Isolates from these patients (53 H. influenzae and 18 H. parainfluenzae) were included to identify, by whole-genome sequencing, antimicrobial resistance changes and genetic variation accumulated during persistent colonization. All persistent lineages isolated before treatment were azithromycin-susceptible but developed resistance within the first months, apart from those belonging to P02, who discontinued the treatment. H. influenzae isolates from P08-ST107 acquired mutations in 23S rRNA, and those from P11-ST2480 and P13-ST165 had changes in L4 and L22. In H. parainfluenzae, P04 persistent isolates acquired changes in rlmC, and P11 carried genes encoding MefE/MsrD efflux pumps in an integrative conjugative element, which was also identified in H. influenzae P11-ST147. Other genetic variation occurred in genes associated with cell wall and inorganic ion metabolism. Persistent H. influenzae strains all showed changes in licA and hgpB genes. Other genes (lex1, lic3A, hgpC, and fadL) had variation in multiple lineages. Furthermore, persistent strains showed loss, acquisition, or genetic changes in prophage-associated regions. Long-term azithromycin therapy results in macrolide resistance, as well as genetic changes that likely favor bacterial adaptation during persistent respiratory colonization. IMPORTANCE The immunomodulatory properties of azithromycin reduce the frequency of exacerbations and improve the quality of life of COPD patients. However, long-term administration may alter the respiratory microbiota, such as Haemophilus influenzae, an opportunistic respiratory colonizing bacteria that play an important role in exacerbations. This study contributes to a better understanding of COPD progression by characterizing the clinical evolution of H. influenzae in a cohort of patients with prolonged azithromycin treatment. The emergence of macrolide resistance during the first months, combined with the role of Haemophilus parainfluenzae as a reservoir and source of resistance dissemination, is a cause for concern that may lead to therapeutic failure. Furthermore, genetic variations in cell wall and inorganic ion metabolism coding genes likely favor bacterial adaptation to host selective pressures. Therefore, the bacterial pathoadaptive evolution in these severe COPD patients raise our awareness of the possible spread of macrolide resistance and selection of host-adapted clones.

Molecular Epidemiology, Antimicrobial Susceptibility, and Clinical Features of Methicillin-Resistant Staphylococcus aureus Bloodstream Infections over 30 Years in Barcelona, Spain (1990-2019).

Methicillin-resistant Staphylococcus aureus bloodstream infections (MRSA-BSI) are a significant cause of mortality. We analysed the evolution of the molecular and clinical epidemiology of MRSA-BSI (n = 784) in adult patients (Barcelona, 1990−2019). Isolates were tested for antimicrobial susceptibility and genotyped (PFGE), and a selection was sequenced (WGS) to characterise the pangenome and mechanisms underlying antimicrobial resistance. Increases in patient age (60 to 71 years), comorbidities (Charlson's index > 2, 10% to 94%), community-onset healthcare-associated acquisition (9% to 60%), and 30-day mortality (28% to 36%) were observed during the 1990−1995 and 2014−2019 periods. The proportion of catheter-related BSIs fell from 57% to 20%. Current MRSA-BSIs are caused by CC5-IV and an upward trend of CC8-IV and CC22-IV clones. CC5 and CC8 had the lowest core genome proportions. Antimicrobial resistance rates fell, and only ciprofloxacin, tobramycin, and erythromycin remained high (>50%) due to GyrA/GrlA changes, the presence of aminoglycoside-modifying enzymes (AAC(6')-Ie-APH(2″)-Ia and ANT(4')-Ia), and mph(C)/msr(A) or erm (C) genes. Two CC22-IV strains showed daptomycin resistance (MprF substitutions). MRSA-BSI has become healthcare-associated, affecting elderly patients with comorbidities and causing high mortality rates. Clonal replacement with CC5-IV and CC8-IV clones resulted in lower antimicrobial resistance rates. The increased frequency of the successful CC22-IV, associated with daptomycin resistance, should be monitored.

Penicillin- and Cephalosporin-Resistant Pneumococcal Meningitis: Treatment in the Real World and in Guidelines.

To report on the therapy used for penicillin- and cephalosporin-resistant pneumococcal meningitis, we conducted an observational cohort study of patients admitted to our hospital with pneumococcal meningitis between 1977 and 2018. According to the European Committee on Antimicrobial Susceptibility Testing (EUCAST) recommendations, we defined pneumococci as susceptible and resistant to penicillin with MIC values of ≤0.06 mg/L and > 0.06 mg/L, respectively; the corresponding values for cefotaxime (CTX) were ≤0.5 mg/L and >0.5 mg/L. We treated 363 episodes of pneumococcal meningitis during the study period. Of these, 24 had no viable strain, leaving 339 episodes with a known MIC for inclusion. Penicillin-susceptible strains accounted for 246 episodes (73%), penicillin-resistant strains for 93 (27%), CTX susceptible for 58, and CTX resistant for 35. Nine patients failed or relapsed and 69 died (20%), of whom 22% were among susceptible cases and 17% were among resistant cases. During the dexamethasone period, mortality was equal (12%) in both susceptible and resistant cases. High-dose CTX (300 mg/Kg/day) helped to treat failed or relapsed cases and protected against failure when used as empirical therapy (P = 0.02), even in CTX-resistant cases. High-dose CTX is a good empirical therapy option for pneumococcal meningitis in the presence of a high prevalence of penicillin and cephalosporin resistance, effectively treating pneumococcal strains with MICs up to 2 mg/L for either penicillin or CTX.

Antimicrobial use and aetiology of bloodstream infections in critically ill patients during early stages of SARS-CoV-2 pandemic.

Background: During early stages of COVID-19 pandemic, antimicrobials were commonly prescribed. Aim: To describe clinical, microbiological and antimicrobial use changes in bloodstream infections (BSI) of ICU patients during the first wave of COVID-19 pandemic compared to pre-COVID-19 era. Methods: Observational cohort study of patients admitted to ICU of Bellvitge University Hospital was conducted during the COVID-19 pandemic (March-June 2020) and before COVID-19 pandemic (March-June 2019). Differences in clinical characteristics, antimicrobial consumption and incidence and aetiology of BSI were measured. Findings: COVID-19 patients had significantly less comorbidities with obesity the only risk factor that increased in frequency. COVID-19 patients more frequently required invasive supportive care measures, had longer median ICU stay and higher mortality rates. The incidence of BSIs was higher in COVID-19 period (RR 3.2 [95%CI 2.2-4.7]), occurred in patients who showed prolonged median ICU stay (21days) and was associated with high mortality rate (47%). The highest increases in the aetiological agents were observed for AmpC-producing bacteria (RR 11.1 [95%CI 2.6-47.9]) and non-fermenting rods (RR 7.0 [95%CI 1.5-31.4]). The emergence of bacteraemia caused by Gram-negative rods resistant to amoxicillin-clavulanate, which was used as empirical therapy during early stages of the pandemic, led to an escalation towards broader-spectrum antimicrobials such as meropenem and colistin which was also associated with the emergence of resistant isolates. Conclusions: The epidemiological shift towards resistant phenotypes in critically ill COVID-19 patients was associated with the selective use of antimicrobials. Our study provides evidence of the impact of empirical therapy on the selection of bacteria and their consequences on BSI over the subsequent months.

Risk Factors and Outcomes of Acute Graft Pyelonephritis with Bacteremia Due to Multidrug-Resistant Gram-Negative Bacilli among Kidney Transplant Recipients.

Acute graft pyelonephritis (AGP) is the leading cause of bloodstream infection in kidney transplant (KT) recipients. The prevalence of urinary tract infections caused by multidrug-resistant (MDR) Gram-negative bacilli is increasing. This 14-year prospective observational study sought to determine the clinical characteristics, risk factors, and outcomes of AGP with bacteremia due to MDR Gram-negative bacilli. Overall, 278 episodes of AGP with bacteremia due to MDR Gram-negative and non-MDR Gram-negative bacilli were identified and compared in 214 KT recipients; MDR Gram-negative bacilli were the cause in 28.4%. Overall 30-day mortality was low (1.1%). Risk factors independently associated with AGP due to MDR Gram-negative bacilli were male sex (OR 3.08; 95%CI 1.60-5.93), previous episode of bacteremic AGP (OR 2.11, 95%CI 1.09-4.09), prior antibiotic therapy in the preceding month (OR 2.47, 95%CI 1.33-4.57), and nosocomial acquisition (OR 2.03, 95%CI 1.14-3.62). Forty-three percent of MDR Gram-negative episodes received inappropriate empirical antibiotic therapy. The risk factors identified in this study may help physicians when selecting empirical antibiotic treatment for AGP. Previous antibiotic use was the main modifiable factor. Its presence highlights the importance of avoiding unnecessary antibiotics in order to bring down the high rates of MDR Gram-negative bacilli infections in this population.

Epidemiology and population structure of Haemophilus influenzae causing invasive disease.

This study provides an update on invasive Haemophilus influenzae disease in Bellvitge University Hospital (2014-2019), reporting its evolution from a previous period (2008-2013) and analysing the non-typeable H. influenzae (NTHi) population structure using a clade-related classification. Clinical data, antimicrobial susceptibility and serotyping were studied and compared with those of the previous period. Population structure was assessed by multilocus sequence typing (MLST), SNP-based phylogenetic analysis and clade-related classification. The incidence of invasive H. influenzae disease remained constant between the two periods (average 2.07 cases per 100 000 population), while the 30 day mortality rate decreased (20.7-14.7 %, respectively). Immunosuppressive therapy (40 %) and malignancy (36 %) were the most frequent comorbidities. Ampicillin and fluoroquinolone resistance rates had increased between the two periods (10-17.6 % and 0-4.4 %, respectively). NTHi was the main cause of invasive disease in both periods (84.3 and 85.3 %), followed by serotype f (12.9 and 8.8 %). NTHi displayed high genetic diversity. However, two clusters of 13 (n=20) and 5 sequence types (STs) (n=10) associated with clade V included NTHi strains of the most prevalent STs (ST3 and ST103), many of which showed increased frequency over time. Moreover, ST103 and ST160 from clade V were associated with ß-lactam resistance. Invasive H. influenzae disease is uncommon, but can be severe, especially in the elderly with comorbidities. NTHi remains the main cause of invasive disease, with ST103 and ST160 (clade V) responsible for increasing ß-lactam resistance over time.

Serotypes in Adult Pneumococcal Pneumonia in Spain in the Era of Conjugate Vaccines.

We studied changes in serotype distribution and antimicrobial susceptibility in adult pneumococcal pneumonia in Spain (2011-2019). Among 895 pneumococci collected (433 bacteremic [BPP] and 462 non-bacteremic [non-BPP]), serotypes 3 (17%), 19A (10%), 8 (6.7%) and 11A (6.7%) were the most frequent. Serotypes 16F, 19A and 24F were associated with old people (≥65) and serotypes 4, 7F, 8, 12F and 19F to young adults. Serotypes 12F, 24F and 1 were significantly more frequent in BPP and serotypes 11A, 23A and 19F in non-BPP. Amoxicillin resistance was higher in non-BPP (17% vs. 11%) while penicillin non-susceptibility (37% vs. 24%) and macrolide resistance (29% vs. 14%) were higher in older adults. In the period 2017-2019, the vaccine coverages were: 32% (PCV13), 39% (PCV15), 65% (PCV20) and 69% (PPV23). Differences were found in serotype composition and antimicrobial resistance by age and type of infection. The maintenance of serotype 3 as a leading cause of adult pneumococcal pneumonia and the increase in highly invasive (serotype 8) or antimicrobial-resistant (serotype 11A) serotypes is worrisome. Further studies will be required to analyse the impact of the upcoming broader conjugate vaccines.

Infectious diseases experts as part of the antibiotic stewardship team in primary care: protocol for a cluster-randomised blinded study (IDASP).

INTRODUCTION: Antibiotic overuse is directly related to antibiotic resistance, and primary care is one of the main reasons for this overuse. This study aims to demonstrate that including experts on infectious diseases (ID) within the antimicrobial stewardship (AMS) programme team in primary care settings achieves higher reductions in overall antibiotic consumption and increases the quality of prescription. METHODS AND ANALYSIS: A multicentre, cluster-randomised, blinded clinical trial will be conducted between 2021 and 2023. Six primary care centres will be randomly assigned to an advanced or a standard AMS programme. The advanced AMS programme will consist of a standard AMS programme combined with the possibility that general practitioners (GP) will discuss patients' therapies with ID experts telephonically during working days and biweekly meetings. The main endpoint will be overall antibiotic consumption, defined as daily defined dose per 1000 inhabitants per day (DHD). Secondary end-points will be: (1) unnecessary antibiotic prescriptions in patients diagnosed with upper respiratory tract or urinary tract infection, (2) adequacy of antibiotic prescription, (3) reattendance to GP or emergency room within 30 days after the initial GP visit and (4) hospital admissions for any reason within 30 days after the GP visit. Two secondary endpoints (unnecessary antibiotic therapy and adequacy of therapy) will be evaluated by blinded investigators.We will select three clusters (centres) per arm (coverage of 147 644 inhabitants) which will allow the rejection of the null hypothesis of equal consumption with a power of 80%, assuming a moderate intracluster correlation of 0.2, an intracluster variance of 4 and a mean difference of 1 DHD. The type I error will be set at 5%. ETHICS AND DISSEMINATION: The protocol was reviewed and approved by local ethics committees. The results of this study will be published in peer-reviewed journals and presented at medical conferences. TRIAL REGISTRATION NUMBER: NCT04848883.

Deciphering mobile genetic elements disseminating macrolide resistance in Streptococcus pyogenes over a 21 year period in Barcelona, Spain.

OBJECTIVES: To phenotypically and genetically characterize the antibiotic resistance determinants and associated mobile genetic elements (MGEs) among macrolide-resistant (MR) Streptococcus pyogenes [Group A streptococci (GAS)] clinical isolates collected in Barcelona, Spain. METHODS: Antibiotic susceptibility testing was performed by microdilution. Isolates were emm and MLST typed and 55 were whole-genome sequenced to determine the nature of the macrolide resistance (MR) determinants and their larger MGE and chromosomal context. RESULTS: Between 1998 and 2018, 142 of 1028 GAS (13.8%) were MR. Among 108 isolates available for molecular characterization, 41.7% had cMLSB, 30.5% iMLSB and 27.8% M phenotype. Eight erm(B)-containing strains were notable in having an MDR phenotype conferred by an MGE encoding several antibiotic resistance genes. MR isolates were comprised of several distinct genetic lineages as defined by the combination of emm and ST. Although most lineages were only transiently present, the emm11/ST403 clone persisted throughout the period. Two lineages, emm9/ST75 with erm(B) and emm77/ST63 with erm(TR), emerged in 2016-18. The erm(B) was predominantly encoded on the Tn916 family of transposons (21/31) with different genetic contexts, and in other MGEs (Tn6263, ICESpHKU372 and one harbouring an MDR cluster called ICESp1070HUB). The erm(TR) was found in ICESp2905 (8/17), ICESp1108-like (4/17), ICESpHKU165 (3/17) and two structures described in this study (IMESp316HUB and ICESp3729HUB). The M phenotype [mef(A)-msr(D)] was linked to phage φ1207.3. Eight integrative conjugative element/integrative mobilizable element (ICE/IME) cluster groups were classified on the basis of gene content within conjugation modules. These groups were found among MGEs, which corresponded with the MR-containing element or the site of integration. CONCLUSIONS: We detected several different MGEs harbouring erm(B) or erm(TR). This is the first known description of Tn6263 in GAS and three MGEs [IMESp316HUB, ICESp3729HUB and ICESp1070HUB] associated with MR. Periods of high MR rates in our area were mainly associated with the expansion of certain predominant lineages, while in low MR periods different sporadic and low prevalence lineages were more frequent.

Genome-wide analysis of urogenital and respiratory multidrug-resistant Haemophilus parainfluenzae.

OBJECTIVES: To characterize the mechanisms of antimicrobial resistance and the prevalence of the polysaccharide capsule among urogenital and respiratory Haemophilus parainfluenzae isolates. METHODS: Antimicrobial susceptibility was tested by microdilution. Fifty-five MDR strains were subjected to WGS and were phylogenetically compared with all the available H. parainfluenzae genomes from the NCBI database. The identification of the capsular bexA gene was performed by PCR in 266 non-MDR strains. RESULTS: In 31 of the 42 ampicillin-resistant strains, blaTEM-1 located within Tn3 was identified. ß-Lactamase-negative cefuroxime-resistant strains (n = 12) presented PBP3 substitutions. The catS gene (n = 14), the tet(M)-MEGA element (n = 18) and FolA substitutions (I95L and F154V/S) (n = 41) were associated with resistance to chloramphenicol, tetracycline plus macrolides, and co-trimoxazole, respectively. Thirty-seven isolates had a Tn10 harbouring tet(B)/(C)/(D)/(R) genes with (n = 15) or without (n = 22) catA2. Putative transposons (Tn7076-Tn7079), including aminoglycoside and co-trimoxazole resistance genes, were identified in 10 strains (18.2%). These transposons were integrated into three new integrative and conjugative elements (ICEs), which also included the resistance-associated transposons Tn3 and Tn10. The capsular operon was found only in the urogenital isolates (18/154, 11.7%), but no phylogenetic clustering was observed. The capsular operons identified were similar to those of Haemophilus influenzae serotype c and Haemophilus sputorum type 2. CONCLUSIONS: The identification of ICEs with up to three resistance-associated transposons suggests that these transferable elements play an important role in the acquisition of multidrug resistance in H. parainfluenzae. Moreover, the presence of polysaccharide capsules in some of these urogenital isolates is a cause for concern.

A historical perspective of MDR invasive pneumococcal disease in Spanish adults.

OBJECTIVES: To analyse the clonal dynamics and clinical characteristics of adult invasive pneumococcal disease (IPD) caused by MDR and penicillin-non-susceptible (PNS) pneumococci in Spain. METHODS: All adult IPD episodes were prospectively collected (1994-2018). Streptococcus pneumoniae isolates were serotyped, genotyped and tested for antimicrobial susceptibility. Changes in the incidence of IPD were analysed and risk factors contributing to MDR were assessed by logistic regression. RESULTS: Of 2095 IPD episodes, 635 (30.3%) were caused by MDR/PNS isolates. Over the study period, the incidence of MDR/PNS-IPD decreased (IRR 0.70; 95% CI 0.53-0.93) whereas that of susceptible isolates remained stable (IRR 0.96; 95% CI 0.80-1.16). A reduction of resistance rates to penicillin (-19.5%; 95% CI -37% to 2%) and cefotaxime (-44.5%; 95% CI -64% to -15%) was observed. Two clones, Spain9V-ST156 and Denmark14-ST230, accounted for 50% of current resistant disease. Among current MDR/PNS isolates, 45.8% expressed serotypes not covered by the upcoming PCV15/PCV20 vaccines. MDR/PNS episodes were associated with older patients with comorbidities, nosocomial acquisition and higher 30 day mortality. MDR/PNS pneumococci were not independently associated with 30 day mortality in multivariate analysis [OR 0.826 (0.648-1.054)]. CONCLUSIONS: Our study shows an overall reduction of MDR/PNS isolates in adults after the introduction of pneumococcal conjugate vaccines. However, a significant proportion of current resistant isolates are not covered by any of the upcoming PCV15/PCV20 vaccines. The burden of resistant disease is related to older patients with underlying conditions and caused by two major clones. Our data show that MDR is not a statistically significant factor related to increased mortality.

Efficacy and Therapeutic Drug Monitoring of Continuous Beta-Lactam Infusion for Osteoarticular Infections Caused by Fluoroquinolone-Resistant Pseudomonas aeruginosa: A Prospective Cohort Study.

BACKGROUND AND OBJECTIVES: Osteoarticular infections (OIs) caused by fluoroquinolone-resistant Pseudomonas aeruginosa, including multidrug-resistant (MDR) and extensively drug-resistant (XDR) strains, have poor outcomes. We evaluated the outcomes of an optimized strategy of continuous beta-lactam infusion (BL-CI) guided by therapeutic drug monitoring (TDM) for OIs caused by fluoroquinolone-resistant P. aeruginosa. METHODS: A prospective observational study of patients with P. aeruginosa OIs in a hospital-based BL-CI program (2016-2018) was carried out. TDM targeting free BL concentrations in plasma (fCss) of at least 3-4 × MIC was performed. We compared failure rates between patients with OIs caused by fluoroquinolone-resistant strains who were treated with BL-CI, with or without colistin, and patients with OIs caused by fluoroquinolone-susceptible strains who were treated with ciprofloxacin. RESULTS: Fifty-two patients were included in the study, 19 (36.5%) of whom had OIs caused by fluoroquinolone-resistant P. aeruginosa (13 (68.4%) MDR/XDR strains; 11 (57.9%) device-related infections). The median duration of BL-CI was 36 days; ten patients (52.6%) received BL-colistin combinations. Eighty-two samples were utilized in the TDM, and most patients were found to have a median fCss of 3-10 × MIC; 17 dose adjustments were performed and eight patients needed dose decreases, five of which were due to chronic kidney disease or acute kidney injury (AKI). BL-CI was well tolerated, with the most frequent adverse event being AKI. Failure occurred to 4 patients (21.1%), which was similar to the failure rate of patients with OIs caused by fluoroquinolone-susceptible P. aeruginosa treated with ciprofloxacin (5/30 [16.7%]) (p = 0.699). TDM was also used in the initial BL treatment of patients with OIs caused by susceptible strains before those patients were switched to treatment with ciprofloxacin alone (33 patients, 110 samples, 19 dose adjustments). CONCLUSIONS: BL-CI used with/without colistin and supported by TDM may be an alternative and effective treatment option for OIs caused by fluoroquinolone-resistant P. aeruginosa, where limited available therapeutic options exist, especially in the setting of multidrug resistance. Future research should elucidate whether this strategy can produce outcomes similar to those of patients treated for OIs caused by fluoroquinolone-susceptible strains.

A multicentre analysis of Nocardia pneumonia in Spain: 2010-2016.

OBJECTIVE: To analyse all cases of Nocardia pneumonia occurring between 2010 and 2016 in five Spanish hospitals. METHODS: This was a retrospective observational analysis of clinical and microbiological data collected from 55 cases of Nocardia pneumonia. RESULTS: There were one to 20 cases per hospital and six to nine cases per year. Chronic obstructive pulmonary disease, bronchiectasis, and asthma were the main predisposing underlying respiratory conditions. Thirty-four patients were receiving systemic and/or inhaled corticosteroids prior to infection, eight had neoplasia, and six had haematological malignancies. Clinical and radiological findings were common to pneumonia of other infectious aetiologies, except for the frequent presence of nodules and cavitation. Overall, the 1-year mortality was high (38.2%), and mortality was directly related to the pulmonary disease in 15 patients (27.3%). The most frequently identified species were N. cyriacigeorgica (n=21), N. abscessus (n=8), and N. farcinica (n=5). All Nocardia isolates were susceptible to linezolid and all but two were susceptible to amikacin and trimethoprim-sulfamethoxazole. CONCLUSIONS: Nocardia pneumonia-associated mortality remains high, probably because of the debilitated status of patients in whom this pathogen is able to cause pulmonary infection.

Emergence of multidrug resistance among Haemophilus parainfluenzae from respiratory and urogenital samples in Barcelona, Spain.

Haemophilus parainfluenzae (HPAR) is a Gram-negative bacterium that can become an opportunistic urogenital pathogen. Recently, multidrug resistant (MDR) strains have emerged. We aim to analyse the epidemiology of HPAR at Hospital Universitari de Bellvitge between 2013 and 2017 to determine its putative role in sexually transmitted infections (STI). Strains were classified by sample origin, and antimicrobial susceptibility was performed by disk-diffusion tested on Mueller-Hinton Fastidious. MDR was defined as the resistance of the antimicrobial to three or more antibiotic class. Molecular typing was performed by pulsed-field gel electrophoresis (PFGE) after restriction with SmaI and Cfr9I. We classified 944 HPAR isolates as being of urogenital (n = 175; 18.5%), respiratory (n = 719; 76.2%), or other (n = 50; 5.3%) origins. Among the urogenital isolates, 50 (28.6%) were MDR, which was significantly higher than that found in respiratory samples (40/719; 5.6%; p < 0.01). The frequency of MDR increased progressively among urogenital samples from 13.3% (2013) to 33.3% (2017) (r = 0.8; p = 0.035). The resistance rates for all 944 episodes were significantly higher for cotrimoxazole (51.4%), tetracycline (46.3%), chloramphenicol (28.0%), ciprofloxacin (21.1%), and ampicillin (20.6%). After PFGE, no clonal relationship was found. Clinical charts were available for 40 symptomatic patients with MDR HPAR infections presenting mostly urethritis (n = 26; 65.0%). In all cases, symptoms were treated effectively with combination therapy. Furthermore, in 10 of those patients with urethritis, MDR HPAR was the only potential pathogen to be identified. The emergence of MDR HPAR is a matter of concern, and the detection as a single pathogen highlights its putative role as cause of STI.

Comparative Antibiofilm Efficacy of Meropenem Alone and in Combination with Colistin in an In Vitro Pharmacodynamic Model by Extended-Spectrum-ß-Lactamase-Producing Klebsiella pneumoniae.

We compared the efficacies of meropenem alone and in combination with colistin against two strains of extended-spectrum-ß-lactamase-producing Klebsiella pneumoniae, using an in vitro pharmacodynamic model that mimicked two different biofilm conditions. Meropenem monotherapy achieved remarkable efficacy (even a bactericidal effect) under all conditions, whereas colistin was almost inactive and resistance emerged. The addition of colistin to meropenem produced no relevant benefits, in contrast to experiences with other microorganisms.