Report of three azole-resistant Aspergillus fumigatus cases with TR34/L98H mutation in hematological patients in Barcelona, Spain.

OBJECTIVES: We aimed to report the emergence of azole-resistant invasive aspergillosis in hematologic patients admitted to a tertiary hospital in Spain during the last 4 months. METHODS: Prospective, descriptive study was performed to describe and follow all consecutive proven and probable invasive aspergillosis resistant to azoles from hematological cohort during the last 4 months. All patients had fungal cultures and antifungal susceptibility or real-time PCR detection for Aspergillus species and real-time PCR detection for azole-resistant mutation. RESULTS: Four cases of invasive aspergillosis were diagnosed in 4 months. Three of them had azole-resistant aspergillosis. Microbiological diagnosis was achieved in three cases by means of fungal culture isolation and subsequent antifungal susceptibility whereas one case was diagnosed by PCR-based aspergillus and azole resistance detection. All the azole-resistant aspergillosis presented TR34/L98H mutation. Patients with azole-resistant aspergillosis had different hematologic diseases: multiple myeloma, lymphoblastic acute leukemia, and angioimmunoblastic T lymphoma. Regarding risk factors, one had prolonged neutropenia, two had corticosteroids, and two had viral co-infection. Two of the patients developed aspergillosis under treatment with azoles. CONCLUSION: We have observed a heightened risk of azole-resistant aspergillosis caused by A. fumigatus harboring the TR34/L98H mutation in patients with hematologic malignancies. The emergence of azole-resistant aspergillosis raises concerns for the community, highlighting the urgent need for increased surveillance and the importance of susceptibility testing and new drugs development.

Real-life epidemiology and current outcomes of hospitalized adults with invasive fungal infections.

We aimed to describe the current epidemiology of both hosts with invasive fungal infections (IFIs) and causative fungi. And, detail outcomes of these infections at 12 weeks in a real-life cohort of hospitalized patients. The study was retrospective and observational to describe IFI diagnosed in a tertiary hospital (February 2017-December 2021). We included all consecutive patients meeting criteria for proven or probable IFI according to EORTC-MSG and other criteria. A total of 367 IFIs were diagnosed. 11.7% were breakthrough infections, and 56.4% were diagnosed in the intensive care unit. Corticosteroid use (41.4%) and prior viral infection (31.3%) were the most common risk factors for IFI. Lymphoma and pneumocystis pneumonia were the most common baseline and fungal diseases. Only 12% of IFI occurred in patients with neutropenia. Fungal cultures were the most important diagnostic tests (85.8%). The most frequent IFIs were candidemia (42.2%) and invasive aspergillosis (26.7%). Azole-resistant Candida strains and non-fumigatus Aspergillus infections represented 36.1% and 44.5% of the cases, respectively. Pneumocystosis (16.9%), cryptococcosis (4.6%), and mucormycosis (2.7%) were also frequent, as well as mixed infections (3.4%). Rare fungi accounted for 9.5% of infections. Overall, IFI mortality at 12 weeks was 32.2%; higher rates were observed for Mucorales (55.6%), Fusarium (50%), and mixed infections (60%). We documented emerging changes in both hosts and real-life IFI epidemiology. Physicians should be aware of these changes to suspect infections and be aggressive in diagnoses and treatments. Currently, outcomes for such clinical scenarios remain extremely poor.

Current epidemiology of the host and fungi and IFI treatments are changing. Real-life data on this subject are scarce. We present our most recent evidence to highlight the importance of the ongoing challenges that require further investigation and clinical adjustments.

Rectal colonization by resistant bacteria increases the risk of infection by the colonizing strain in critically ill patients with cirrhosis.

BACKGROUND & AIMS: It remains unclear whether rectal colonization with multidrug-resistant organisms (MDROs) is prevalent and predisposes to infections by the same pathogens in patients with cirrhosis. METHODS: Two series of critically ill patients were evaluated. In the Barcelona cohort, 486 consecutive patients were prospectively evaluated, 129 with and 357 without cirrhosis (2015-2016). Rectal swabs were performed at admission and weekly thereafter (until intensive care unit [ICU] discharge) to detect MDRO colonization. Risk factors for colonization and infection by MDROs were evaluated. A retrospective cohort from Frankfurt (421 patients with cirrhosis; 2010-2018) was investigated to evaluate MDRO rectal colonization in another epidemiological scenario. RESULTS: In the Barcelona cohort, 159 patients were colonized by MDROs (32.7%), 102 (64.2%) at admission and 57 (35.8%) during follow-up. Patients with cirrhosis showed higher rates of rectal colonization at admission than those without cirrhosis (28.7% vs. 18.2%, p = 0.01) but similar colonization rates during ICU stay. Extended-spectrum beta-lactamase-Enterobacterales were the most frequent MDROs isolated in both groups. Colonization by MDROs independently increased the risk of infection by MDROs at admission and during follow-up. Risk of new infection by the colonizing strain was also significantly increased in patients with (hazard ratio [HR] 7.41) and without (HR 5.65) cirrhosis. Rectal colonization by MDROs was also highly prevalent in Frankfurt (n = 198; 47%; 131 at admission [66.2%] and 67 [33.8%] during follow-up), with vancomycin-resistant enterococci being the most frequent colonizing organism. Rectal colonization by MDROs was also associated with an increased risk of infection by MDROs in this cohort. Infections occurring in MDR carriers were mainly caused by the colonizing strain. CONCLUSION: Rectal colonization by MDROs is extremely frequent in critically ill patients with cirrhosis. Colonization increases the risk of infection by the colonizing resistant strain. LAY SUMMARY: Rectal colonization by multidrug-resistant organisms (MDROs) is a prevalent problem in patients with cirrhosis requiring critical care. The pattern of colonizing bacteria is heterogeneous with relevant differences between centers. Colonization by MDROs is associated with increased risk of infection by the colonizing bacteria in the short term. This finding suggests that colonization data could be used to guide empirical antibiotic therapy and de-escalation policies in patients with cirrhosis.

Impact of Empirical Antibiotic Regimens on Mortality in Neutropenic Patients with Bloodstream Infection Presenting with Septic Shock.

We analyzed risk factors for mortality in febrile neutropenic patients with bloodstream infections (BSI) presenting with septic shock and assessed the impact of empirical antibiotic regimens. A multicenter retrospective study (2010 to 2019) of two prospective cohorts compared BSI episodes in patients with or without septic shock. Multivariate analysis was performed to identify independent risk factors for mortality in episodes with septic shock. Of 1,563 patients with BSI, 257 (16%) presented with septic shock. Those patients with septic shock had higher mortality than those without septic shock (55% versus 15%, P < 0.001). Gram-negative bacilli caused 81% of episodes with septic shock, Gram-positive cocci caused 22%, and Candida species caused 5%. Inappropriate empirical antibiotic treatment (IEAT) was administered in 17.5% of septic shock episodes. Empirical ß-lactam combined with other active antibiotics was associated with the lowest mortality observed. When amikacin was the only active antibiotic, mortality was 90%. Addition of empirical specific Gram-positive coverage had no impact on mortality. Mortality was higher when IEAT was administered (76% versus 51%, P = 0.002). Age of >70 years (odds ratio [OR], 2.3; 95% confidence interval [CI], 1.2 to 4.7), IEAT for Candida spp. or Gram-negative bacilli (OR, 3.8; 95% CI, 1.3 to 11.1), acute kidney injury (OR, 2.6; 95% CI, 1.4 to 4.9), and amikacin as the only active antibiotic (OR, 15.2; 95% CI, 1.7 to 134.5) were independent risk factors for mortality, while the combination of ß-lactam and amikacin was protective (OR, 0.32; 95% CI, 0.18 to 0.57). Septic shock in febrile neutropenic patients with BSI is associated with extremely high mortality, especially when IEAT is administered. Combination therapy including an active ß-lactam and amikacin results in the best outcomes.

Infective Endocarditis: New Challenges in a Classic Disease.

Infective endocarditis is a relatively rare, but deadly infection, with an overall mortality of around 20% in most series. Clinical manifestations have evolved in response to significant epidemiological shifts in industrialized nations, with a move toward a nosocomial or health-care-related pattern, in older patients, with more episodes associated with prostheses and/or intravascular electronic devices and a predominance of staphylococcal and enterococcal etiology.Diagnosis is often challenging and is based on the conjunction of clinical, microbiological, and imaging information, with notable progress in recent years in the accuracy of echocardiographic data, coupled with the recent emergence of other useful imaging techniques such as cardiac computed tomography (CT) and nuclear medicine tools, particularly 18F-fluorodeoxyglucose positron emission/CT.The choice of an appropriate treatment for each specific case is complex, both in terms of the selection of the appropriate agent and doses and durations of therapy as well as the possibility of using combined bactericidal antibiotic regimens in the initial phase and finalizing treatment at home in patients with good evolution with outpatient oral or parenteral antimicrobial therapies programs. A relevant proportion of patients will also require valve surgery during the active phase of treatment, the timing of which is extremely difficult to define. For all the above, the management of infective endocarditis requires a close collaboration of multidisciplinary endocarditis teams.

Emergence of Resistance to Novel Cephalosporin-ß-Lactamase Inhibitor Combinations through the Modification of the Pseudomonas aeruginosa MexCD-OprJ Efflux Pump.

A ceftolozane-tazobactam- and ceftazime-avibactam-resistant Pseudomonas aeruginosa isolate was recovered after treatment (including azithromycin, meropenem, and ceftolozane-tazobactam) from a patient that had developed ventilator-associated pneumonia after COVID-19 infection. Whole-genome sequencing revealed that the strain, belonging to ST274, had acquired a nonsense mutation leading to truncated carbapenem porin OprD (W277X), a 7-bp deletion (nt213Δ7) in NfxB (negative regulator of the efflux pump MexCD-OprJ), and two missense mutations (Q178R and S133G) located within the first large periplasmic loop of MexD. Through the construction of mexD mutants and complementation assays with wild-type nfxB, it was evidenced that resistance to the novel cephalosporin-ß-lactamase inhibitor combinations was caused by the modification of MexD substrate specificity.

Effectiveness of vancomycin plus cloxacillin compared with vancomycin, cloxacillin and daptomycin single therapies in the treatment of methicillin-resistant and methicillin-susceptible Staphylococcus aureus in a rabbit model of experimental endocarditis.

OBJECTIVES: To investigate if the addition of cloxacillin to vancomycin enhances the activity of both monotherapies for treating MSSA and MRSA experimental endocarditis (EE) in rabbits. METHODS: Vancomycin plus cloxacillin was compared with the respective monotherapies and daptomycin. In vitro time-kill studies were performed using standard (105 cfu) and high (108 cfu) inocula of five MRSA, one glycopeptide-intermediate (GISA) and five MSSA strains. One MSSA (MSSA-678) and one MRSA (MRSA-277) strain were selected to be used in the in vivo model. A human-like pharmacokinetics model was applied and the equivalents of cloxacillin 2 g/4 h IV and daptomycin 6 mg/kg/day IV were administered. To optimize vancomycin activity, dosage was adjusted to achieve an AUC/MIC ≥400. RESULTS: Daptomycin sterilized significantly more vegetations than cloxacillin (13/13, 100% versus 9/15, 60%; P = 0.02) and showed a trend of better activity than vancomycin (10/14, 71%; P = 0.09) and vancomycin plus cloxacillin (10/14, 71%; P = 0.09) against MSSA-678. Addition of cloxacillin to vancomycin (13/15, 87%) was significantly more effective than vancomycin (8/16, 50%; P = 0.05) and showed similar activity to daptomycin (13/18, 72%; P = 0.6) against MRSA-277. In all treatment arms, the bacterial isolates recovered from vegetations were re-tested and showed the same daptomycin susceptibility as the original strains. CONCLUSIONS: Vancomycin plus cloxacillin proved synergistic and bactericidal activity against MRSA. Daptomycin was the most efficacious option against MSSA and similar to vancomycin plus cloxacillin against MRSA. In settings with high MRSA prevalence, vancomycin plus cloxacillin might be a good alternative for empirical therapy of S. aureus IE.

Dissemination of NDM-producing Klebsiella pneumoniae and Escherichia coli high-risk clones in Catalan healthcare institutions.

OBJECTIVES: To characterize the clonal spread of carbapenem-resistant Klebsiella pneumoniae and Escherichia coli isolates between different healthcare institutions in Catalonia, Spain. METHODS: Antimicrobial susceptibility was tested by disc diffusion. MICs were determined by gradient diffusion or broth microdilution. Carbapenemase production was confirmed by lateral flow. PCR and Sanger sequencing were used to identify the allelic variants of resistance genes. Clonality studies were performed by PFGE and MLST. Plasmid typing, conjugation assays, S1-PFGE plus Southern blotting and MinION Oxford Nanopore sequencing were used to characterize resistance plasmids. RESULTS: Twenty-nine carbapenem-resistant isolates recovered from three healthcare institutions between January and November 2016 were included: 14 K. pneumoniae isolates from a tertiary hospital in the south of Catalonia (hospital A); 2 K. pneumoniae isolates from a nearby healthcare centre; and 12 K. pneumoniae isolates and 1 E. coli isolate from a tertiary hospital in Barcelona (hospital B). The majority of isolates were resistant to all antimicrobial agents, except colistin, and all were NDM producers. PFGE identified a major K. pneumoniae clone (n = 27) belonging to ST147 and co-producing NDM-1 and CTX-M-15, with a few isolates also harbouring blaOXA-48. Two sporadic isolates of K. pneumoniae ST307 and E. coli ST167 producing NDM-7 were also identified. blaNDM-1 was carried in two related IncR plasmid populations and blaNDM-7 in a conjugative 50 kb IncX3 plasmid. CONCLUSIONS: We report the inter-hospital dissemination of XDR high-risk clones of K. pneumoniae and E. coli associated with the carriage of small, transferable plasmids harbouring blaNDM genes.

Antibiotic-resistant microorganisms in patients with bloodstream infection of intraabdominal origin: risk factors and impact on mortality.

BACKGROUND: Knowledge of resistance patterns is essential to choose empirical treatment. We aimed to determine the risk factors for antibiotic-resistant microorganisms (ARM) in intraabdominal infections (IAI) and their impact on mortality. METHODS: Retrospective cohort study of patients with bacteremia from IAI origin in a single hospital between January 2006 and July 2017. RESULTS: A total of 1485 episodes were recorded, including 381 (25.6%) due to ARM. Independent predictors of ARM were cirrhosis (OR 2; [95% CI 1.15-3.48]), immunosuppression (OR 1.49; 1.12-1.97), prior ceftazidime exposure (OR 3.7; 1.14-11.9), number of prior antibiotics (OR 2.33; 1.61-3.35 for 1 antibiotic), biliary manipulation (OR 1.53; 1.02-2.96), hospital-acquisition (OR 2.77; 1.89-4) and shock (OR 1.48; 1.07-2). Mortality rate of the whole cohort was 11.1%. Age (OR 1.03; 1.01-1.04), cirrhosis (OR 2.32; 1.07-4.38), urinary catheter (OR 1.99; 1.17-3.38), ultimately (OR 2.28; 1.47-3.51) or rapidly (OR 13.3; 7.12-24.9) fatal underlying disease, nosocomial infection (OR 2.76; 1.6-4.75), peritonitis (OR 1.95, 1.1-3.45), absence of fever (OR 2.17; 1.25-3.77), shock (OR 5.96; 3.89-9.13), and an ARM in non-biliary infections (OR 2.14; 1.19-3.83) were independent predictors of 30-day mortality. Source control (OR 0.24; 0.13-0.44) and 2015-2017 period (OR 0.29; 0.14-0.6) were protective. CONCLUSION: Biliary manipulation and septic shock are predictors of ARM. The presence of an ARM from a non-biliary focus is a poor-prognosis indicator. Source control continues to be of paramount importance.

Inappropriate Empirical Antibiotic Treatment in High-risk Neutropenic Patients With Bacteremia in the Era of Multidrug Resistance.

BACKGROUND: We aimed to describe the current rates of inappropriate empirical antibiotic treatment (IEAT) in oncohematological patients with febrile neutropenia (FN) and its impact on mortality. METHODS: This was a multicenter prospective study of all episodes of bloodstream infection (BSI) in high-risk FN patients (2006-2017). Episodes receiving IEAT were compared with episodes receiving appropriate empirical therapy. Adherence to Infectious Diseases Society of America (IDSA) recommendations was evaluated. Multivariate analysis was performed to identify independent risk factors for mortality in Pseudomonas aeruginosa episodes. RESULTS: Of 1615 episodes, including Escherichia coli (24%), coagulase-negative staphylococci (21%), and P. aeruginosa (16%), 394 (24%) received IEAT despite IDSA recommendations being followed in 87% of cases. Patients with multidrug-resistant gram-negative bacilli (MDR-GNB), accounting for 221 (14%) of all isolates, were more likely to receive IEAT (39% vs 7%, P < .001). Overall mortality was higher in patients with GNB BSI who received IEAT (36% vs 24%, P = .004); when considering individual microorganisms, only patients with infection caused by P. aeruginosa experienced a significant increase in mortality when receiving IEAT (48% vs 31%, P = .027). Independent risk factors for mortality in PA BSI (odds ratio [95% confidence interval] were IEAT (2.41 [1.19-4.91]), shock at onset (4.62 [2.49-8.56]), and pneumonia (3.01 [1.55-5.83]). CONCLUSIONS: IEAT is frequent in high-risk patients with FN and BSI, despite high adherence to guidelines. This inappropriate treatment primarily impacts patients with P. aeruginosa-related BSI mortality and in turn is the only modifiable factor to improve outcomes.

Relationship between Vancomycin MIC and Virulence Gene Expression in Clonal Complexes of Methicillin-Susceptible Staphylococcus aureus Strains Isolated from Left-Sided Endocarditis.

Higher vancomycin MICs have been associated with more complicated courses and higher mortality rates in patients with Staphylococcus aureus bacteremia and infective endocarditis (IE). The aim of this study was to investigate whether the strains belonging to the cohort of 93 patients from a previously published study in which patients with strains with vancomycin MICs of ≥1.5 µg/ml presented higher mortality rates and systemic emboli than patients with strains with vancomycin MICs of <1.5 µg/ml had specific patterns of virulence factors, clonal complex (CC) types, or the ability to form biofilms. Vancomycin MICs were determined by Etest, and the isolates underwent spa typing to infer the CC, biofilm studies, a thrombin-induced platelet microbicidal assay, and multiplex PCR for the presence of virulence genes. We found no differences in genes encoding adhesins, toxins, or other putative virulence genes according to the vancomycin MIC group. CC30, CC34, and CC45 represented nearly half of the isolates, and there was no association with the vancomycin MIC. agr subgroups I and III predominated, with no association with the vancomycin MIC. Isolates with higher vancomycin MICs exhibited a poorer ability to form biofilms with and without the presence of vancomycin (2.03 versus 2.48 [P < 0.001], respectively, for isolates with higher vancomycin MICs and 2.60 versus 2.87 [P = 0.022], respectively, for isolates with lower vancomycin MICs). In the multivariable analysis, efb and V8 were risk factors for major emboli (adjusted odds ratio [aOR] = 7.5 and 95% confidence interval [CI] = 1.2 to 46.6 for efb, and aOR = 3.9 and 95% CI = 1.1 to 14.1 for V8), whereas no genotypic predictors of in-hospital mortality were found. No clear associations between genes encoding virulence factors, agr type, clonal complexes, mortality, and major embolic events according to vancomycin MIC group were found.

An evidence-based bundle improves the quality of care and outcomes of patients with candidaemia.

BACKGROUND: Candidaemia is a leading cause of bloodstream infections in hospitalized patients all over the world. It remains associated with high mortality. OBJECTIVES: To assess the impact of implementing an evidence-based package of measures (bundle) on the quality of care and outcomes of candidaemia. METHODS: A systematic review of the literature was performed to identify measures related to better outcomes in candidaemia. Eight quality-of-care indicators (QCIs) were identified and a set of written recommendations (early treatment, echinocandins in septic shock, source control, follow-up blood culture, ophthalmoscopy, echocardiography, de-escalation, length of treatment) was prospectively implemented. The study was performed in 11 tertiary hospitals in Spain. A quasi-experimental design before and during bundle implementation (September 2016 to February 2018) was used. For the pre-intervention period, data from the prospective national surveillance were used (May 2010 to April 2011). RESULTS: A total of 385 and 263 episodes were included in the pre-intervention and intervention groups, respectively. Adherence to all QCIs improved in the intervention group. The intervention group had a decrease in early (OR 0.46; 95% CI 0.23-0.89; P = 0.022) and overall (OR 0.61; 95% CI 0.4-0.94; P = 0.023) mortality after controlling for potential confounders. CONCLUSIONS: Implementing a structured, evidence-based intervention bundle significantly improved patient care and early and overall mortality in patients with candidaemia. Institutions should embrace this objective strategy and use the bundle as a means to measure high-quality medical care of patients.

Cloxacillin or fosfomycin plus daptomycin combinations are more active than cloxacillin monotherapy or combined with gentamicin against MSSA in a rabbit model of experimental endocarditis.

BACKGROUND: In vitro and in vivo activity of daptomycin alone or plus either cloxacillin or fosfomycin compared with cloxacillin alone and cloxacillin plus gentamicin were evaluated in a rabbit model of MSSA experimental endocarditis (EE). METHODS: Five MSSA strains were used in the in vitro time-kill studies at standard (105-106 cfu/mL) and high (108 cfu/mL) inocula. In the in vivo EE model, the following antibiotic combinations were evaluated: cloxacillin (2 g/4 h) alone or combined with gentamicin (1 mg/kg/8 h) or daptomycin (6 mg/kg once daily); and daptomycin (6 mg/kg/day) alone or combined with fosfomycin (2 g/6 h). RESULTS: At standard and high inocula, daptomycin plus fosfomycin or cloxacillin were bactericidal against 4/5 and 5/5 strains, respectively, while cloxacillin plus gentamicin was bactericidal against 3/5 strains at standard inocula but against none at high inocula. Fosfomycin, cloxacillin, gentamicin and daptomycin MIC/MBCs of the MSSA-678 strain used in the EE model were: 8/64, 0.25/0.5, 0.25/0.5 and 1/8 mg/L, respectively. Adding gentamicin to cloxacillin significantly reduced bacterial density in vegetations compared with cloxacillin monotherapy (P = 0.026). Adding fosfomycin or cloxacillin to daptomycin [10/11 (93%) and 8/11 (73%), respectively] significantly improved the efficacy of daptomycin in sterilizing vegetations [0/11 (0%), P < 0.001 for both combinations] and showed better activity than cloxacillin alone [0/10 (0%), P < 0.001 for both combinations] and cloxacillin plus gentamicin [3/10 (30%), P = 0.086 for cloxacillin plus daptomycin and P = 0.008 for fosfomycin plus daptomycin]. No recovered isolates showed increased daptomycin MIC. CONCLUSIONS: The addition of cloxacillin or fosfomycin to daptomycin is synergistic and rapidly bactericidal, showing better activity than cloxacillin plus gentamicin for treating MSSA EE, supporting their clinical use.

Factors associated with the development of septic shock in patients with candidemia: a post hoc analysis from two prospective cohorts.

BACKGROUND: Almost one third of the patients with candidemia develop septic shock. The understanding why some patients do and others do not develop septic shock is very limited. The objective of this study was to identify variables associated with septic shock development in a large population of patients with candidemia. METHODS: A post hoc analysis was performed on two prospective, multicenter cohort of patients with candidemia from 12 hospitals in Spain and Italy. All episodes occurring from September 2016 to February 2018 were analyzed to assess variables associated with septic shock development defined according to The Third International Consensus Definition for Sepsis and Septic Shock (Sepsis-3). RESULTS: Of 317 candidemic patients, 99 (31.2%) presented septic shock attributable to candidemia. Multivariate logistic regression analysis identifies the following factors associated with septic shock development: age > 50 years (OR 2.57, 95% CI 1.03-6.41, p = 0.04), abdominal source of the infection (OR 2.18, 95% CI 1.04-4.55, p = 0.04), and admission to a general ward at the time of candidemia onset (OR 0.21, 95% CI, 0.12-0.44, p = 0.001). Septic shock development was independently associated with a greater risk of 30-day mortality (OR 2.14, 95% CI 1.08-4.24, p = 0.02). CONCLUSIONS: Age and abdominal source of the infection are the most important factors significantly associated with the development of septic shock in patients with candidemia. Our findings suggest that host factors and source of the infection may be more important for development of septic shock than intrinsic virulence factors of organisms.

Emergence of Resistance to Quinolones and ß-Lactam Antibiotics in Enteroaggregative and Enterotoxigenic Escherichia coli Causing Traveler's Diarrhea.

The objective of this study was to assess the antimicrobial resistance of enteroaggregative Escherichia coli (EAEC) and enterotoxigenic E. coli (ETEC) strains causing traveler's diarrhea (TD) and to investigate the molecular characterization of antimicrobial resistance genes to third-generation cephalosporins, cephamycins, and quinolones. Overall, 39 EAEC and 43 ETEC clinical isolates were studied. The susceptibilities of EAEC and ETEC against ampicillin, amoxicillin-clavulanic acid, cefotaxime, imipenem, chloramphenicol, tetracycline, co-trimoxazole, nalidixic acid, ciprofloxacin, azithromycin, and rifaximin were determined. All genes encoding resistance determinants were detected by PCR or PCR plus DNA sequencing. The epidemiology of selected EAEC and ETEC strains was studied using multilocus sequence typing (MLST). The resistance to quinolones of EAEC and ETEC strains causing TD has significantly increased over the last decades, and high percentages have been found especially in patients traveling to India and sub-Saharan Africa. Sequence type 38 (ST38) and ST131, carrying the blaCTX-M-15 and blaCTX-M-27 genes, respectively, are highly prevalent among extended-spectrum ß-lactamase (ESBL)-producing EAEC and ETEC strains. The cephamycinase ACT-20 is described in the present study for the first time in EAEC and ETEC strains causing TD in patients who had traveled to Central America. The percentages of resistance to azithromycin in EAEC and ETEC isolates from patients to Southeast Asia/India and Africa are above 25%. Meanwhile, rifaximin is still active against EAEC and ETEC, with the prevalence of resistant strains not being high. In conclusion, fluoroquinolones should no longer be considered the drugs of choice for the prevention or treatment in TD for travelers traveling to India and Africa. Azithromycin and rifaximin are still a good alternative to treat TD caused by EAEC or ETEC.

Endocarditis Caused by Highly Penicillin-Resistant Viridans Group Streptococci: Still Room for Vancomycin-Based Regimens.

Optimal treatment options remain unknown for infective endocarditis (IE) caused by penicillin-resistant (PEN-R) viridans group streptococcal (VGS) strains. The aims of this study were to report two cases of highly PEN-R VGS IE, perform a literature review, and evaluate various antibiotic combinations in vitro and in vivo The following combinations were tested by time-kill studies and in the rabbit experimental endocarditis (EE) model: PEN-gentamicin, ceftriaxone-gentamicin, vancomycin-gentamicin, daptomycin-gentamicin, and daptomycin-ampicillin. Case 1 was caused by Streptococcus parasanguinis (PEN MIC, 4 µg/ml) and was treated with vancomycin plus cardiac surgery. Case 2 was caused by Streptococcus mitis (PEN MIC, 8 µg/ml) and was treated with 4 weeks of vancomycin plus gentamicin, followed by 2 weeks of vancomycin alone. Both patients were alive and relapse-free after ≥6 months follow-up. For the in vitro studies, except for daptomycin-ampicillin, all combinations demonstrated both synergy and bactericidal activity against the S. parasanguinis isolate. Only PEN-gentamicin, daptomycin-gentamicin, and daptomycin-ampicillin demonstrated both synergy and bactericidal activity against the S. mitis strain. Both strains developed high-level daptomycin resistance (HLDR) during daptomycin in vitro passage. In the EE studies, PEN alone failed to clear S. mitis from vegetations, while ceftriaxone and vancomycin were significantly more effective (P < 0.001). The combination of gentamicin with PEN or vancomycin increased bacterial eradication compared to that with the respective monotherapies. In summary, two patients with highly PEN-R VGS IE were cured using vancomycin-based therapy. In vivo, regimens of gentamicin plus either ß-lactams or vancomycin were more active than their respective monotherapies. Further clinical studies are needed to confirm the role of vancomycin-based regimens for highly PEN-R VGS IE. The emergence of HLDR among these strains warrants caution in the use of daptomycin therapy for VGS IE.

Perioperative prophylaxis with ertapenem reduced infections caused by extended-spectrum betalactamase-producting Enterobacteriaceae after kidney transplantation.

BACKGOUND: In recent years we have witnessed an increase in infections due to multidrug-resistant organisms in kidney transplant recipients (KTR). In our setting, we have observed a dramatic increase in infections caused by extended-spectrum betalactamase-producing (ESBL) Enterobacteriaceae in KTR. In 2014 we changed surgical prophylaxis from Cefazolin 2 g to Ertapenem 1 g. METHODS: We compared bacterial infections and their resistance phenotype during the first post-transplant month with an historical cohort collected during 2013 that had received Cefazolin. RESULTS: During the study period 110 patients received prophylaxis with Cefazolin and 113 with Ertapenem. In the Ertapenem cohort we observed a non-statistically significant decrease in the percentage of early bacterial infection from 57 to 47%, with urine being the most frequent source in both. The frequency of infections caused by Enterobacteriaceae spp. decreased from 64% in the Cefazolin cohort to 36% in the Ertapenem cohort (p = 0.005). In addition, percentage of ESBL-producing strains decreased from 21 to 8% of all Enterobacteriaceae isolated (p = 0.015). After adjusted in multivariate Cox regression analysis, male sex (HR 0.16, 95%CI: 0.03-0.75), cefazolin prophylaxis (HR 4.7, 95% CI: 1.1-22.6) and acute rejection (HR 14.5, 95% CI: 1.3-162) were associated to ESBL- producing Enterobacteriaceae infection. CONCLUSIONS: Perioperative antimicrobial prophylaxis with a single dose of Ertapenem in kidney transplant recipients reduced the incidence of early infections due to ESBL-producing Enterobacteriaceae without increasing the incidence of other multidrug-resistant microorganisms or C. difficile.

Epidemiology, Clinical Features, and Outcome of Infective Endocarditis due to Abiotrophia Species and Granulicatella Species: Report of 76 Cases, 2000-2015.

Background: Infective endocarditis (IE) caused by Abiotrophia (ABI) and Granulicatella (GRA) species is poorly studied. This work aims to describe and compare the main features of ABI and GRA IE. Methods: We performed a retrospective study of 12 IE institutional cases of GRA or ABI and of 64 cases published in the literature (overall, 38 ABI and 38 GRA IE cases). Results: ABI/GRA IE represented 1.51% of IE cases in our institution between 2000 and 2015, compared to 0.88% of HACEK (Haemophilus, Aggregatibacter, Cardiobacterium, Eikenella, Kingella)-related IE and 16.62% of Viridans group streptococci (VGS) IE. Institutional ABI/GRA IE case characteristics were comparable to that of VGS, but periannular complications were more frequent (P = .008). Congenital heart disease was reported in 4 (10.5%) ABI and in 11 (28.9%) GRA cases (P = .04). Mitral valve was more frequently involved in ABI than in GRA (P < .001). Patient sex, prosthetic IE, aortic involvement, penicillin susceptibility, and surgical treatment were comparable between the genera. New-onset heart failure was the most frequent complication without genera differences (P = .21). Five (13.2%) ABI patients and 2 (5.3%) GRA patients died (P = .23). Factors associated with higher mortality were age (P = .02) and new-onset heart failure (P = .02). The genus (GRA vs ABI) was not associated with higher mortality (P = .23). Conclusions: GRA/ABI IE was more prevalent than HACEK IE and approximately one-tenth as prevalent as VGS; periannular complications were more frequent. GRA and ABI genera IE presented similar clinical features and outcomes. Overall mortality was low, and related to age and development of heart failure.

The Combination of Daptomycin and Fosfomycin Has Synergistic, Potent, and Rapid Bactericidal Activity against Methicillin-Resistant Staphylococcus aureus in a Rabbit Model of Experimental Endocarditis.

We investigated whether the addition of fosfomycin or cloxacillin to daptomycin provides better outcomes in the treatment of methicillin-resistant Staphylococcus aureus (MRSA) experimental aortic endocarditis in rabbits. Five MRSA strains were used to perform in vitro time-kill studies using standard (106) and high (108) inocula. Combined therapy was compared to daptomycin monotherapy treatment in the MRSA experimental endocarditis model. A human-like pharmacokinetics model was applied, and the equivalents of cloxacillin at 2 g/4 h, fosfomycin at 2 g/6 h, and daptomycin at 6 to 10 mg/kg/day were administered intravenously. A combination of daptomycin and either fosfomycin or cloxacillin was synergistic in the five strains tested at both inocula. A bactericidal effect was detected in four of five strains tested with both combinations. The MRSA-277 strain (vancomycin MIC, 2 µg/ml) was used for the experimental endocarditis model. Daptomycin plus fosfomycin significantly improved the efficacy of daptomycin monotherapy at 6 mg/kg/day in terms of both the proportion of sterile vegetations (100% versus 72%, P = 0.046) and the decrease in the density of bacteria within the vegetations (P = 0.025). Daptomycin plus fosfomycin was as effective as daptomycin monotherapy at 10 mg/kg/day (100% versus 93%, P = 1.00) and had activity similar to that of daptomycin plus cloxacillin when daptomycin was administered at 6 mg/kg/day (100% versus 88%, P = 0.48). Daptomycin nonsusceptibility was not detected in any of the isolates recovered from vegetations. In conclusion, for the treatment of MRSA experimental endocarditis, the combination of daptomycin plus fosfomycin showed synergistic and bactericidal activity.