Phenotypic and genotypic analysis of antimicrobial resistance and population structure of gastroenteritis-related Aeromonas isolates.

BACKGROUND: The population structure and the correlation between antimicrobial resistance (AMR) phenotypes and genotypes in Aeromonas species isolated from patients with gastroenteritis are not well understood. The aims of the study were to: (1) investigate the antimicrobial susceptibility profiles of Aeromonas species isolated from patients with gastroenteritis; (2) explore the relationship between AMR genes and resistance phenotypes; and (3) describe the population structure of these isolates and provide evidence of transmission events among them. METHODS: This microbiological survey was performed at the Microbiology Laboratory of the Emek Medical Center in Afula, Israel. Cultivation of Aeromonas was attempted from stool samples that tested positive by PCR. Antimicrobial susceptibility testing (AST) was performed using the Sensititre GN3F microdilution panel. Whole genome sequencing (WGS) was done using the Illumina NextSeq500/550 system. Phylogenetic studies involved multi-locus sequence typing (MLST) and core genome (cg) MLST. Resistance mechanisms were identified using the Comprehensive Antibiotic Resistance Database and compared with the AST results. RESULTS: The study included 67 patient-unique isolates. The species that were identified included A. caviae (n = 58), A. dhakensis (n = 3), A. media (n = 2), A. veronii (n = 2) and A. hydrophila (n = 2). Isolates were almost uniformly susceptible to amikacin, gentamicin, aztreonam, cefepime, ceftazidime, ciprofloxacin and meropenem. All isolates with the exception of 1-2 isolates were resistant to ampicillin, cefazolin and ampicillin-sulbactam which was compatible with the presence of the blaOXA genes. Variable resistance rates were observed to cefuroxime, cefoxitin, ceftriaxone, piperacillin-tazobactam that were not correlated with the presence of other ß-lactamase genes. Resistance to tetracycline and trimethoprim-sulfamethoxazole correlated with the presence of tetA and sul1, respectively. The population structure of A. caviae was highly diverse with the minority of the isolates (16/57) clustering into six defined sequence types. A cgMLST-based distance of four genes was found in one pair of isolates, suggesting common source transmission. CONCLUSIONS: A. caviae is the dominant species related to gastroenteritis and is characterized by a diverse population structure, with almost no evidence for common-source transmission. Resistance rates to most antimicrobial agents were low and partially matched with the presence of resistance genes.

The effect of the transition to molecular diagnosis on the epidemiology and the clinical characteristics of bacterial gastroenteritis in Northern Israel.

BACKGROUND: The transition to PCR-based diagnosis of bacterial gastroenteritis (BGE) can increase the sensitivity but might reduce the clinical specificity. The aims of this study were (1) to compare the effect of the change from culture to PCR-based diagnostics on the reported incidence and positivity rates of BGE due to Salmonella, Shigella and Campylobacter species and (2) to compare the demographics, medical background, clinical characteristics and pre-analytic variables between cases with PCR-positive, culture-negative samples to cases with PCR-positive, culture-positive samples. METHODS: The study was performed at the Emek Medical Centre that serves a population of 0.5 million people in Northern Israel. The study included two parts: (1) a retrospective cohort study, comparing the incidence and positivity rates of laboratory-diagnosed BGE from January 2016 until December 22nd, 2019 when culture was the sole method to January 2020 until April 2023 when PCR was used; (2) a prospective cohort study, conducted between November 2020 until April 2023 that compared the demographics and clinical characteristics of BGE cases that were diagnosed by PCR alone versus cases that were diagnosed by both PCR and culture. RESULTS: The incidence rate between-periods comparability ratio was only 113% since the incidence rate did not increase during 2020, the first year of the COVID-19 pandemic. The sample positivity rate increased since 2020, with between-periods comparability ratio of 159%. In the second period, the sample positivity rates of culture vs. PCR alone differed between the pathogens and were 90.2%, 63.8% and 54.2% for Salmonella, Campylobacter and Shigella species, respectively (p < 0.001). The following variables were identified as independent predictors of culture positivity: (1) Salmonella infection (O.R. = 10.6, 95% C.I. 3.6-31.1, p < 0.001); (2) Shigella infection (O.R. = 0.46, 95% C.I.0.23-0.93, p = 0.032); (3) time from sample submission to culture (O.R.=0.73, 95% C.I. 0.58-0.92, p = 0.008); (4) the presence of abdominal pain (O.R. = 1.98, 95% C.I. 1.04-3.79, p = 0.038) and the PCR mean Ct value (O.R. = 0.89, 95% C.I.0.85-0.94, p < 0.001). CONCLUSIONS: The use of PCR had led to improved sensitivity, without noticeable decrease in the clinical specificity. This was especially important in the case of the more fastidious organisms.

Correlates of protection for booster doses of the SARS-CoV-2 vaccine BNT162b2.

Vaccination, especially with multiple doses, provides substantial population-level protection against COVID-19, but emerging variants of concern (VOC) and waning immunity represent significant risks at the individual level. Here we identify correlates of protection (COP) in a multicenter prospective study following 607 healthy individuals who received three doses of the Pfizer-BNT162b2 vaccine approximately six months prior to enrollment. We compared 242 individuals who received a fourth dose to 365 who did not. Within 90 days of enrollment, 239 individuals contracted COVID-19, 45% of the 3-dose group and 30% of the four-dose group. The fourth dose elicited a significant rise in antibody binding and neutralizing titers against multiple VOCs reducing the risk of symptomatic infection by 37% [95%CI, 15%-54%]. However, a group of individuals, characterized by low baseline titers of binding antibodies, remained susceptible to infection despite significantly increased neutralizing antibody titers upon boosting. A combination of reduced IgG levels to RBD mutants and reduced VOC-recognizing IgA antibodies represented the strongest COP in both the 3-dose group (HR = 6.34, p = 0.008) and four-dose group (HR = 8.14, p = 0.018). We validated our findings in an independent second cohort. In summary combination IgA and IgG baseline binding antibody levels may identify individuals most at risk from future infections.

Outcomes of octogenarians and nonagenarians with Pseudomonas aeruginosa bacteremia: a multicenter retrospective study.

BACKGROUND: P. aeruginosa bacteremia is a common and severe infection carrying high mortality in older adults. We aimed to evaluate outcomes of P. aeruginosa bacteremia among old adults (≥ 80 years). METHODS: We included the 464/2394 (19%) older adults from a retrospective multinational (9 countries, 25 centers) cohort study of individuals hospitalized with P. aeruginosa bacteremia. Bivariate and multivariable logistic regression models were used to evaluate risk factors for 30-day mortality among older adults. RESULTS: Among 464 adults aged ≥ 80 years, the mean age was 84.61 (SD 3.98) years, and 274 (59%) were men. Compared to younger patients, ≥ 80 years adults had lower Charlson score; were less likely to have nosocomial acquisition; and more likely to have urinary source. Thirty-day mortality was 30%, versus 27% among patients 65-79 years (n = 894) and 25% among patients < 65 years (n = 1036). Multivariate analysis for predictors of mortality among patients ≥ 80 years, demonstrated higher SOFA score (odds ratio [OR] 1.36, 95% confidence interval [CI] 1.23-1.51, p < 0.001), corticosteroid therapy (OR 3.15, 95% CI: 1.24-8.01, p = 0.016) and hospital acquired P. aeruginosa bacteremia (OR 2.30, 95% CI: 1.33-3.98, p = 0.003) as predictors. Appropriate empirical therapy within 24 h, type of definitive anti-pseudomonal drug, and type of regimen (monotherapy or combination) were not associated with 30-day mortality. CONCLUSIONS: In older adults with P. aeruginosa bacteremia, background conditions, place of acquisition, and disease severity are associated with mortality, rather than the antimicrobial regimen. In this regard, preventive efforts and early diagnosis before organ failure develops might be beneficial for improving outcomes.

Hospitalized Patients With Severe Coronavirus Disease 2019 During the Omicron Wave in Israel: Benefits of a Fourth Vaccine Dose.

BACKGROUND: Waning immunity and an increased incidence of coronavirus disease 2019 (COVID-19) during the Omicron outbreak led the Israeli Ministry of Health to recommend a fourth vaccine dose for high-risk individuals. In this study, we assessed its effect for hospitalized patients with severe breakthrough COVID-19. METHODS: In this multicenter cohort study of hospitalized adults with severe COVID-19 in Israel, from 15 to 31 January 2022, cases were divided according to the number of vaccinations received. Poor outcome was defined as mechanical ventilation or in-hospital death and was compared between 3- and 4-dose vaccinees using logistic regression. RESULTS: Included were 1049 patients, median age 80 years. Among them, 394 were unvaccinated, 386 and 88 had received 3 or 4 doses, respectively. The 3-dose group was older, included more males, and immunosuppressed patients but with similar outcomes, 49% vs 51% compared with unvaccinated patients (P = .72). Patients who received 4 doses were similarly older and immunosuppressed but had better outcomes compared with unvaccinated patients, 34% vs 51% (P < .01). We examined independent predictors for poor outcome in patients who received either 3 or 4 doses a median of 161 days or 14 days before diagnosis, respectively. Receipt of the fourth dose was associated with protection (odds ratio, 0.51; 95% confidence interval, .3-.87), as was remdesivir. Male sex, chronic renal failure, and dementia were associated with poor outcomes. CONCLUSIONS: Among hospitalized patients with severe breakthrough COVID-19, a recent fourth dose was associated with significant protection against mechanical ventilation or death compared with 3 doses.

Healthcare-associated infection prevention and control practices in Israel: results of a national survey.

BACKGROUND: Healthcare-associated infection (HAI) is a common and largely preventable cause of morbidity and mortality. The COVID-19 pandemic has presented unprecedented challenges to health systems. We conducted a national survey to ascertain hospital characteristics and the use of HAI prevention measures in Israel. METHODS: We e-mailed surveys to infection prevention and control (IPC) leads of acute care hospitals in Israel. The survey included questions about the use of practices to prevent catheter-associated urinary tract infection (CAUTI), central line-associated bloodstream infection (CLABSI), ventilator-associated pneumonia (VAP), and Clostridioides difficile infection (CDI). The survey also assessed COVID-19 impact and healthcare worker well-being. RESULTS: IPC leads from 15 of 24 invited hospitals (63%) completed the survey. Only one-third of respondents reported strong support for IPC from hospital leadership. Although several prevention practices were used by all hospitals (e.g., maximum sterile barrier precautions for CLABSI and real-time assessment of environmental cleaning for CDI), use of other practices was suboptimal-particularly for CAUTI and VAP. COVID-19 had a profound impact on Israeli hospitals, with all hospitals reporting opening of new units to care for COVID patients and most reporting moderate to extreme financial hardship. All hospitals reported highly successful plans to vaccinate all staff and felt confident that the vaccine is safe and effective. CONCLUSION: We provide a status report of the IPC characteristics and practices Israeli hospitals are currently using to prevent HAIs during the COVID-19 era. While many globally accepted IPC practices are widely implemented, opportunities to increase the use of certain IPC practices in Israeli hospitals exist.

Invasive Fungal Diseases in Hospitalized Patients with COVID-19 in Israel: A Multicenter Cohort Study.

Highly variable estimates of COVID-19-associated fungal diseases (IFDs) have been reported. We aimed to determine the incidence of clinically important fungal diseases in hospitalized COVID-19 patients during the first year of the pandemic. We performed a multicenter survey of IFDs among patients hospitalized with COVID-19 in 13 hospitals in Israel between February 2020 and May 2021. COVID-19-associated pulmonary mold disease (PMD) and invasive candidiasis (IC) were defined using ECMM/ISHAM and EORTC/MSG criteria, respectively. Overall rates of IC and PMD among patients with critical COVID-19 were 10.86 and 10.20 per 1000 admissions, respectively, with significant variability among medical centers. PMD rates were significantly lower in centers where galactomannan was a send-out test versus centers with on-site testing (p = 0.035). The 30-day mortality rate was 67.5% for IC and 57.5% for PMD. Treatment with an echinocandin for IC or an extended-spectrum azole for PMD was associated with significantly lower mortality rates (adjusted hazard ratio [95% confidence interval], 0.26 [0.07-0.91] and 0.23 [0.093-0.57], respectively). In this multicenter national survey, variable rates of PMD were associated with on-site galactomannan testing, suggesting under-detection in sites lacking this capacity. COVID-19-related IFDs were associated with high mortality rates, which were reduced with appropriate antifungal therapy.

Duration of Treatment for Pseudomonas aeruginosa Bacteremia: a Retrospective Study.

INTRODUCTION: There is no consensus regarding optimal duration of antibiotic therapy for Pseudomonas aeruginosa bacteremia. We aimed to evaluate the impact of short antibiotic course. METHODS: We present a retrospective multicenter study including patients with P. aeruginosa bacteremia during 2009-2015. We evaluated outcomes of patients treated with short (6-10 days) versus long (11-15 days) antibiotic courses. The primary outcome was a composite of 30-day mortality or bacteremia recurrence and/or persistence. Univariate and inverse probability treatment-weighted (IPTW) adjusted multivariate analysis for the primary outcome was performed. To avoid immortal time bias, the landmark method was used. RESULTS: We included 657 patients; 273 received a short antibiotic course and 384 a long course. There was no significant difference in baseline characteristics of patients. The composite primary outcome occurred in 61/384 patients in the long-treatment group (16%) versus 32/273 in the short-treatment group (12%) (p = 0.131). Mortality accounted for 41/384 (11%) versus 25/273 (9%) of cases, respectively. Length of hospital stay was significantly shorter in the short group [median 13 days, interquartile range (IQR) 9-21 days, versus median 15 days, IQR 11-26 days, p = 0.002]. Ten patients in the long group discontinued antibiotic therapy owing to adverse events, compared with none in the short group. On univariate and multivariate analyses, duration of therapy was not associated with the primary outcome. CONCLUSIONS: In this retrospective study, 6-10 days of antibiotic course for P. aeruginosa bacteremia were as effective as longer courses in terms of survival and recurrence. Shorter therapy was associated with reduced length of stay and less drug discontinuation.

Seroprevalence of SARS-CoV2 among Healthcare Workers: A Prospective Study.

BACKGROUND: Healthcare workers (HCWs) have close interaction with confirmed or suspected coronavirus disease 2019 (COVID-19) patients. Infection rates reported among HCWs is between 3% and 17%, and asymptomatic HCWs are a potential source of nosocomial transmission to vulnerable patients and colleagues. Universal mask use and good supply of personal protective equipment was implemented early at our institution. OBJECTIVES: To determine the rate of infection by the serologic status of HCWs during first three COVID-19 waves, based on occupation and risk of exposure, compared to Israeli general population. METHODS: We conducted a prospective cohort study at Emek Medical Center from April 2020 to April 2021. A total of 101 HCWs volunteered to be followed at six time points by a serology test and a questionnaire. RESULTS: A total of 101 HCWs completed six serologic tests. All participants were seronegative at the four initial tests. The cumulative seropositivity rate for COVID-19 in HCWs was 9.9% (10/101). Only three seropositive HCWs (2.97%) were hospital-acquired. CONCLUSIONS: Seroprevalence and seroconversion dynamics of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in 101 HCWs during COVID-19 outbreaks at Emek Medical Center were similar to the epidemiological curve of positive polymerase chain reaction results of the Israeli population, as published by the Israeli Ministry of Health, at each time point. Universal mask use and infection control measures may have contributed to a low hospital infection rate.

Hospitalised patients with breakthrough COVID-19 following vaccination during two distinct waves in Israel, January to August 2021: a multicentre comparative cohort study.

BackgroundChanging patterns of vaccine breakthrough can clarify vaccine effectiveness.AimTo compare breakthrough infections during a SARS-CoV-2 Delta wave vs unvaccinated inpatients, and an earlier Alpha wave.MethodsIn an observational multicentre cohort study in Israel, hospitalised COVID-19 patients were divided into three cohorts: breakthrough infections in Comirnaty-vaccinated patients (VD; Jun-Aug 2021) and unvaccinated cases during the Delta wave (ND) and breakthrough infections during an earlier Alpha wave (VA; Jan-Apr 2021). Primary outcome was death or ventilation.ResultsWe included 343 VD, 162 ND and 172 VA patients. VD were more likely older (OR: 1.06; 95% CI: 1.05-1.08), men (OR: 1.6; 95% CI: 1.0-2.5) and immunosuppressed (OR: 2.5; 95% CI: 1.1-5.5) vs ND. Median time between second vaccine dose and admission was 179 days (IQR: 166-187) in VD vs 41 days (IQR: 28-57.5) in VA. VD patients were less likely to be men (OR: 0.6; 95% CI: 0.4-0.9), immunosuppressed (OR: 0.3; 95% CI: 0.2-0.5) or have congestive heart failure (OR: 0.6; 95% CI: 0.3-0.9) vs VA. The outcome was similar between all cohorts and affected by age and immunosuppression and not by vaccination, variant or time from vaccination.ConclusionsVaccination was protective during the Delta variant wave, as suggested by older age and greater immunosuppression in vaccinated breakthrough vs unvaccinated inpatients. Nevertheless, compared with an earlier post-vaccination period, breakthrough infections 6 months post-vaccination occurred in healthier patients. Thus, waning immunity increased vulnerability during the Delta wave, which suggests boosters as a countermeasure.

The Effect of Macrolides on Mortality in Bacteremic Pneumococcal Pneumonia: A Retrospective, Nationwide Cohort Study, Israel, 2009-2017.

BACKGROUND: Previous cohort studies of pneumonia patients reported lower mortality with advanced macrolides. Our aim was to characterize antibiotic treatment patterns and assess the role of quinolones or macrolides in empirical therapy. MATERIALS: An historical cohort, 1 July 2009 to 30 June 2017, included, through active surveillance, all culture-confirmed bacteremic pneumococcal pneumonia (BPP) among adults in Israel. Cases without information on antibiotic treatment were excluded. Logistic regression analysis was used to assess independent predictors of in-hospital mortality. RESULTS: A total of 2016 patients with BPP were identified. The median age was 67.2 years (interquartile range [IQR] 53.2-80.6); 55.1% were men. Lobar pneumonia was present in 1440 (71.4%), multi-lobar in 576 (28.6%). Median length of stay was 6 days (IQR 4-11). A total of 1921 cases (95.3%) received empiric antibiotics with anti-pneumococcal coverage: ceftriaxone, in 1267 (62.8%). Coverage for atypical bacteria was given to 1159 (57.5%), 64% of these, with macrolides. A total of 372 (18.5%) required mechanical ventilation, and 397 (19.7%) died. Independent predictors of mortality were age (odds ratio [OR] 1.051, 95% confidence interval [CI] 1.039, 1.063), being at high-risk for pneumococcal disease (OR 2.040, 95% CI 1.351, 3.083), multi-lobar pneumonia (OR 2.356, 95% CI 1.741, 3.189). Female sex and macrolide therapy were predictors of survival: (OR 0.702, 95% CI .516, .955; and OR 0.554, 95% CI .394, .779, respectively). Either azithromycin or roxithromycin treatment for as short as two days was predictor of survival. Quinolone therapy had no effect. CONCLUSIONS: Empirical therapy with macrolides reduced odds for mortality by 45%. This effect was evident with azithromycin and with roxithromycin. The effect did not require a full course of therapy.

Early effectiveness of BNT162b2 Covid-19 vaccine in preventing SARS-CoV-2 infection in healthcare personnel in six Israeli hospitals (CoVEHPI).

BACKGROUND: Methodologically rigorous studies on Covid-19 vaccine effectiveness (VE) in preventing SARS-CoV-2 infection are critically needed to inform national and global policy on Covid-19 vaccine use. In Israel, healthcare personnel (HCP) were initially prioritized for Covid-19 vaccination, creating an ideal setting to evaluate early real-world VE in a closely monitored population. METHODS: We conducted a prospective study among HCP in 6 hospitals to estimate the effectiveness of the BNT162b2 mRNA Covid-19 vaccine in preventing SARS-CoV-2 infection. Participants filled out weekly symptom questionnaires, provided weekly nasal specimens, and three serology samples - at enrollment, 30 days and 90 days. We estimated VE against PCR-confirmed SARS-CoV-2 infection using the Cox Proportional Hazards model and against a combined PCR/serology endpoint using Fisher's exact test. RESULTS: Of the 1567 HCP enrolled between December 27, 2020 and February 15, 2021, 1250 previously uninfected participants were included in the primary analysis; 998 (79.8%) were vaccinated with their first dose prior to or at enrollment, all with Pfizer BNT162b2 mRNA vaccine. There were four PCR-positive events among vaccinated participants, and nine among unvaccinated participants. Adjusted two-dose VE against any PCR-confirmed infection was 94.5% (95% CI: 82.6%-98.2%); adjusted two-dose VE against a combined endpoint of PCR and seroconversion for a 60-day follow-up period was 94.5% (95% CI: 63.0%-99.0%). Five PCR-positive samples from study participants were sequenced; all were alpha variant. CONCLUSIONS: Our prospective VE study of HCP in Israel with rigorous weekly surveillance found very high VE for two doses of Pfizer BNT162b2 mRNA vaccine against SARS-CoV-2 infection in recently vaccinated HCP during a period of predominant alpha variant circulation. FUNDING: Clalit Health Services.

Candida Bloodstream Infection, a Dire Complication in Hospitalized COVID-19 Patients: Three Cases from a Single Center in Northern Israel.

BACKGROUND: Patients with severe coronavirus disease-2019 (COVID-19) are susceptible to superimposed infections. OBJECTIVES: To describe COVID-19 patients who presented with complications due to Candida bloodstream co-infection (candidemia) and their outcome in a single center in northern Israel (Emek Medical Center) during the second outbreak of COVID-19 in Israel (15 June 2020 to 20 September 2020). METHODS: A retrospective study of COVID-19 patients presenting with candidemia was conducted, including clinical and laboratory data. The incidence of candidemia among hospitalized COVID-19 patients was compared to a historical cohort of non-COVID-19 controls. RESULTS: Three COVID-19 patients complicated with candidemia were documented. All three patients died shortly after the detection of candidemia. Three different Candida sp. were isolated from the blood cultures: C. albicans, C. parapsilosis, and C. glabrata. The incidence of candidemia among COVID-19 patients was 0.679 episodes per 1000 hospital days. CONCLUSIONS: Our small sample suggests a much higher incidence of candidemia among COVID-19 patients compared to a historical cohort of non-COVID-19 controls. All clinicians treating COVID-19 patients in GICU should be aware of this complication.

BNT162b2 vaccine breakthrough: clinical characteristics of 152 fully vaccinated hospitalized COVID-19 patients in Israel.

OBJECTIVES: The mRNA coronavirus disease 2019 (COVID-19) vaccines have shown high effectiveness in the prevention of symptomatic COVID-19, hospitalization, severe disease and death. Nevertheless, a minority of vaccinated individuals might become infected and experience significant morbidity. Characteristics of vaccine breakthrough infections have not been studied. We sought to portray the population of Israeli patients, who were hospitalized with COVID-19 despite full vaccination. METHODS: A retrospective multicentre cohort study of 17 hospitals included patients fully vaccinated with Pfizer/BioNTech's BNT162b2 vaccine who developed COVID-19 more than 7 days after the second vaccine dose and required hospitalization. The risk for poor outcome, defined as a composite of mechanical ventilation or death, was assessed. RESULTS: A total of 152 patients were included, accounting for half of hospitalized fully vaccinated patients in Israel. Poor outcome was noted in 38 patients and mortality rate reached 22% (34/152). Notably, the cohort was characterized by a high rate of co-morbidities predisposing to severe COVID-19, including hypertension (108; 71%), diabetes (73; 48%), congestive heart failure (41; 27%), chronic kidney and lung diseases (37; 24% each), dementia (29; 19%) and cancer (36; 24%), and only six (4%) had no co-morbidities. Sixty (40%) of the patients were immunocompromised. Higher viral load was associated with a significant risk for poor outcome. Risk also appeared higher in patients receiving anti-CD20 treatment and in patients with low titres of anti-Spike IgG, but these differences did not reach statistical significance. CONCLUSIONS: We found that severe COVID-19 infection, associated with a high mortality rate, might develop in a minority of fully vaccinated individuals with multiple co-morbidities. Our patients had a higher rate of co-morbidities and immunosuppression compared with previously reported non-vaccinated hospitalized individuals with COVID-19. Further characterization of this vulnerable population may help to develop guidance to augment their protection, either by continued social distancing, or by additional active or passive vaccinations.

Combination versus monotherapy as definitive treatment for Pseudomonas aeruginosa bacteraemia: a multicentre retrospective observational cohort study.

BACKGROUND: Pseudomonas aeruginosa bacteraemia is a common and serious infection. No consensus exists regarding whether definitive combination therapy is superior to monotherapy. We aimed to evaluate the impact of combination therapy on mortality. METHODS: This was a multicentre retrospective study (nine countries, 25 centres), including 1277 patients with P. aeruginosa bacteraemia during 2009-15. We evaluated the association between ß-lactam plus aminoglycoside or quinolone combination therapy versus ß-lactam monotherapy and mortality. The primary outcome was 30 day all-cause mortality. Univariate and multivariate Cox regression analyses were conducted, introducing combination as a time-dependent variable. Propensity score was conducted to adjust for confounding for choosing combination therapy over monotherapy. RESULTS: Of 1119 patients included, 843 received definitive monotherapy and 276 received combination therapy (59% aminoglycoside and 41% quinolone). Mortality at 30 days was 16.9% (189/1119) and was similar between combination (45/276; 16.3%) and monotherapy (144/843; 17.1%) groups (P = 0.765). In multivariate Cox regression, combination therapy was not associated with reduced mortality (HR 0.98, 95% CI 0.64-1.53). No advantage in terms of clinical failure, microbiological failure or recurrent/persistent bacteraemia was demonstrated using combination therapy. Likewise, adverse events and resistance development were similar for the two regimens. CONCLUSIONS: In this retrospective cohort, no mortality advantage was demonstrated using combination therapy over monotherapy for P. aeruginosa bacteraemia. Combination therapy did not improve clinical or microbiological failure rates, nor affect adverse events or resistance development. Our finding of no benefit with combination therapy needs confirmation in well-designed randomized controlled trials.

The Bacteriology of Acute Cholecystitis: Comparison of Bile Cultures and Clinical Outcomes in Diabetic and Non-Diabetic Patients.

BACKGROUND: Acute cholecystitis is one of the most common acute surgical diseases. Diabetic patients have been shown to have an increased risk for gallbladder disease, but the correlation between the severity of gallstone disease and diabetes is still debated. The aim of this study is to examine the possible difference in the disease process between patients with diabetes mellitus (DM) and those without. PATIENTS AND METHODS: A retrospective study was conducted of all patients who underwent percutaneous cholecystostomy between 2005 and 2015 at Emek Medical Center, Afula, Israel. Demographic and medical history including data on bile and blood culture results, antimicrobial susceptibility, and clinical outcomes were retrieved from patient files. RESULTS: The cohort included 272 patients. Mean age was 68 years old, 50.74% were male and 43.75% had diabetes mellitus. Bile cultures were obtained from 252 (92.64%) patients and were positive in 134 (53.2%) patients. In 11 patients (4%) two pathogens were isolated. Blood cultures obtained from 231 patients and were positive in 35 (15.2%). Escherichia coli was the most common isolate, and was seen in 22.3% of positive bile cultures and 40% of blood cultures. Although diabetic patients had significantly more positive bile cultures, the severity of the disease, according to the Tokyo guidelines, was not higher. CONCLUSIONS: Acute cholecystitis was neither more severe nor had significant difference in bacteriological properties when comparing diabetic patients to non-diabetic ones.

Malaria Disease and Chemoprophylaxis Usage among Israeli Travelers to Endemic Countries.

Prevention of malaria in travelers to endemic countries is one of the complex challenges of travel medicine. Israel has a widespread culture of travel to developing countries, but information regarding malaria prevention is limited so far. Our study, conducted in Sheba Medical Center, Israel, during the years 2008-2018 examined malaria chemoprophylaxis usage and malaria cases in a large group of Israeli travelers returning from endemic countries with any medical complaint. Data were collected regarding travel destinations, conditions, duration of stay, and pretravel consultation. Altogether, 4,708 travelers were included in our study. Travel destinations included Asia (51%), Latin America (31%), and sub-Saharan Africa (SSA) (17%). Median travel duration was 26 days. Only 11.9% reported taking malaria chemoprophylaxis. Of the travelers to SSA, 41.3% took prophylaxis as opposed to only 6% outside of Africa. During the study years, 136 cases of malaria were diagnosed; among them, 82 (60%) were infected with Plasmodium falciparum, of whom all but two were from SSA and none adhered to prophylaxis. Malaria chemoprophylaxis usage was found to be negligible in travel to many countries still considered endemic. Higher prophylaxis usage was found among travelers to SSA, but numbers are still lower than recommended. The low number of malaria cases seen in destinations outside SSA, as documented in our cohort, is likely to represent travel to low risk areas and not high prophylaxis usage. We urge re-evaluation of current CDC and Israeli guidelines which still recommend using chemoprophylaxis in many low-risk countries, as focus on high-risk countries may increase adherence.

Ceftazidime, Carbapenems, or Piperacillin-tazobactam as Single Definitive Therapy for Pseudomonas aeruginosa Bloodstream Infection: A Multisite Retrospective Study.

BACKGROUND: The optimal antibiotic regimen for Pseudomonas aeruginosa bacteremia is controversial. Although ß-lactam monotherapy is common, data to guide the choice between antibiotics are scarce. We aimed to compare ceftazidime, carbapenems, and piperacillin-tazobactam as definitive monotherapy. METHODS: A multinational retrospective study (9 countries, 25 centers) including 767 hospitalized patients with P. aeruginosa bacteremia treated with ß-lactam monotherapy during 2009-2015. The primary outcome was 30-day all-cause mortality. Univariate and multivariate, including propensity-adjusted, analyses were conducted introducing monotherapy type as an independent variable. RESULTS: Thirty-day mortality was 37/213 (17.4%), 42/210 (20%), and 55/344 (16%) in the ceftazidime, carbapenem, and piperacillin-tazobactam groups, respectively. Type of monotherapy was not significantly associated with mortality in either univariate, multivariate, or propensity-adjusted analyses (odds ratio [OR], 1.14; 95% confidence interval [CI], 0.52-2.46, for ceftazidime; OR, 1.3; 95% CI, 0.67-2.51, for piperacillin-tazobactam, with carbapenems as reference in propensity adjusted multivariate analysis; 542 patients). No significant difference between antibiotics was demonstrated for clinical failure, microbiological failure, or adverse events. Isolation of P. aeruginosa with new resistance to antipseudomonal drugs was significantly more frequent with carbapenems (36/206 [17.5%]) versus ceftazidime (25/201 [12.4%]) and piperacillin-tazobactam (28/332 [8.4%] (P = .007). CONCLUSIONS: No significant difference in mortality, clinical, and microbiological outcomes or adverse events was demonstrated between ceftazidime, carbapenems, and piperacillin-tazobactam as definitive treatment of P. aeruginosa bacteremia. Higher rates of resistant P. aeruginosa after patients were treated with carbapenems, along with the general preference for carbapenem-sparing regimens, suggests using ceftazidime or piperacillin-tazobactam for treating susceptible infection.

Risk factors for mortality among patients with Pseudomonas aeruginosa bacteraemia: a retrospective multicentre study.

This study aimed to evaluate risk factors for 30-day mortality among hospitalised patients with Pseudomonas aeruginosa bacteraemia, a highly fatal condition. A retrospective study was conducted between 1 January 2009 and 31 October 2015 in 25 centres (9 countries) including 2396 patients. Univariable and multivariable analyses of risk factors were conducted for the entire cohort and for patients surviving ≥48 h. A propensity score for predictors of appropriate empirical therapy was introduced into the analysis. Of the 2396 patients, 636 (26.5%) died within 30 days. Significant predictors (odds ratio and 95% confidence interval) of mortality in the multivariable analysis included patient-related factors: age (1.02, 1.01-1.03); female sex (1.34, 1.03-1.77); bedridden functional capacity (1.99, 1.24-3.21); recent hospitalisation (1.43, 1.07-1.92); concomitant corticosteroids (1.33, 1.02-1.73); and Charlson comorbidity index (1.05, 1.01-1.93). Infection-related factors were multidrug-resistant Pseudomonas (1.52, 1.15-2.1), non-urinary source (2.44, 1.54-3.85) and Sequential Organ Failure Assessment (SOFA) score (1.27, 1.18-1.36). Inappropriate empirical therapy was not associated with increased mortality (0.81, 0.49-1.33). Among 2135 patients surviving ≥48 h, hospital-acquired infection (1.59, 1.21-2.09), baseline endotracheal tube (1.63, 1.13-2.36) and ICU admission (1.53, 1.02-2.28) were additional risk factors. Risk factors for mortality among patients with P. aeruginosa were mostly irreversible. Early appropriate empirical therapy was not associated with reduced mortality. Further research should be conducted to explore subgroups that may not benefit from broad-spectrum antipseudomonal empirical therapy. Efforts should focus on prevention of infection, mainly hospital-acquired infection and multidrug-resistant pseudomonal infection.