Antimicrobial surveillance: A 20-year history of the SMART approach to addressing global antimicrobial resistance into the future

Antimicrobial resistance (AMR) is a major global public health threat, particularly affecting patients in resource-poor settings. Comprehensive surveillance programmes are essential to reducing the high mortality and morbidity associated with AMR and are integral to informing treatment decisions and guidelines, appraising the effectiveness of intervention strategies, and directing development of new antibacterial agents. Various surveillance programmes exist worldwide, including those administered by government bodies or funded by the pharmaceutical industry. One of the largest and longest running industry-sponsored AMR surveillance programme is the Study for Monitoring Antimicrobial Resistance Trends (SMART), which recently completed its 20th year. The SMART database has grown to almost 500 000 isolates from over 200 sites in more than 60 countries, encompassing all major geographic regions and including many sites in low- and middle-income countries. The SMART surveillance programme has evolved in scope over time, including additional antibacterial agents, pathogens and infection sites, in line with changing epidemiology and medical need. Surveillance data from SMART and similar programmes have been used successfully to detect emerging resistance threats and AMR patterns in specific countries and regions, thus informing national and local clinical treatment guidelines. The SMART database can be accessed readily by physicians and researchers globally, which may be especially valuable to those from countries with limited healthcare resources, where surveillance and resistance data are rarely collected. Continued participation from as many sites as possible worldwide and maintenance of adequate funding are critical factors to fully realising the potential of large-scale AMR surveillance programmes into the future.

Ceftolozane/tazobactam for hospital-acquired/ventilator-associated bacterial pneumonia due to ESBL-producing Enterobacterales: a subgroup analysis of the ASPECT-NP clinical trial

BACKGROUND

After the MERINO trial with piperacillin/tazobactam, the efficacy of β-lactam/tazobactam combinations in serious infections involving extended-spectrum β-lactamase (ESBL)-producing pathogens merits special evaluation.

OBJECTIVES

To further confirm the efficacy of ceftolozane/tazobactam in treating hospital-acquired/ventilator-associated bacterial pneumonia (HABP/VABP) involving ESBL-positive and/or AmpC-producing Enterobacterales.

METHODS

Retrospective subgroup analysis of the ASPECT-NP trial comparing ceftolozane/tazobactam with meropenem for treating HABP/VABP in mechanically ventilated adults (ClinicalTrials.gov NCT02070757). ESBLs were identified using whole genome sequencing. Chromosomal AmpC production was quantified employing a high-sensitivity mRNA transcription assay.

RESULTS

Overall, 61/726 (8.4%) participants had all baseline lower respiratory tract (LRT) isolates susceptible to both study treatments and ≥1 baseline ESBL-positive/AmpC-overproducing Enterobacterales isolate. In this subgroup (ceftolozane/tazobactam n = 30, meropenem n = 31), baseline characteristics were generally comparable between treatment arms. The most frequent ESBL-positive and/or AmpC-overproducing Enterobacterales isolates (ceftolozane/tazobactam n = 31, meropenem n = 35) overall were Klebsiella pneumoniae (50.0%), Escherichia coli (22.7%), and Proteus mirabilis (7.6%). The most prevalent ESBLs were CTX-M-15 (75.8%), other CTX-M (19.7%), and SHV (4.5%); 10.6% of isolates overproduced chromosomal AmpC. Overall, 28 day all-cause mortality was 6.7% (2/30) with ceftolozane/tazobactam and 32.3% (10/31) with meropenem (25.6% difference, 95% CI: 5.54 to 43.84). Clinical cure rate at test-of-cure, 7-14 days after end of therapy, was 73.3% (22/30) with ceftolozane/tazobactam and 61.3% (19/31) with meropenem (12.0% difference, 95% CI: -11.21 to +33.51). Per-isolate microbiological response at test-of-cure was 64.5% (20/31) with ceftolozane/tazobactam and 74.3% (26/35) with meropenem (-9.8% difference, 95% CI: -30.80 to +12.00).

CONCLUSIONS

These data confirm ceftolozane/tazobactam as an effective treatment option for HABP/VABP involving ceftolozane/tazobactam-susceptible ESBL-positive and/or AmpC-producing Enterobacterales.

Ceftolozane/tazobactam versus meropenem in patients with ventilated hospital-acquired bacterial pneumonia: subset analysis of the ASPECT-NP randomized, controlled phase 3 trial

Background

Ceftolozane/tazobactam is approved for treatment of hospital-acquired/ventilator-associated bacterial pneumonia (HABP/VABP) at double the dose approved for other infection sites. Among nosocomial pneumonia subtypes, ventilated HABP (vHABP) is associated with the lowest survival. In the ASPECT-NP randomized, controlled trial, participants with vHABP treated with ceftolozane/tazobactam had lower 28-day all-cause mortality (ACM) than those receiving meropenem. We conducted a series of post hoc analyses to explore the clinical significance of this finding.

Methods

ASPECT-NP was a multinational, phase 3, noninferiority trial comparing ceftolozane/tazobactam with meropenem for treating vHABP and VABP; study design, efficacy, and safety results have been reported previously. The primary endpoint was 28-day ACM. The key secondary endpoint was clinical response at test-of-cure. Participants with vHABP were a prospectively defined subgroup, but subgroup analyses were not powered for noninferiority testing. We compared baseline and treatment factors, efficacy, and safety between ceftolozane/tazobactam and meropenem in participants with vHABP. We also conducted a retrospective multivariable logistic regression analysis in this subgroup to determine the impact of treatment arm on mortality when adjusted for significant prognostic factors.

Results

Overall, 99 participants in the ceftolozane/tazobactam and 108 in the meropenem arm had vHABP. 28-day ACM was 24.2% and 37.0%, respectively, in the intention-to-treat population (95% confidence interval [CI] for difference: 0.2, 24.8) and 18.2% and 36.6%, respectively, in the microbiologic intention-to-treat population (95% CI 2.5, 32.5). Clinical cure rates in the intention-to-treat population were 50.5% and 44.4%, respectively (95% CI − 7.4, 19.3). Baseline clinical, baseline microbiologic, and treatment factors were comparable between treatment arms. Multivariable regression identified concomitant vasopressor use and baseline bacteremia as significantly impacting ACM in ASPECT-NP; adjusting for these two factors, the odds of dying by day 28 were 2.3-fold greater when participants received meropenem instead of ceftolozane/tazobactam.

Conclusions

There were no underlying differences between treatment arms expected to have biased the observed survival advantage with ceftolozane/tazobactam in the vHABP subgroup. After adjusting for clinically relevant factors found to impact ACM significantly in this trial, the mortality risk in participants with vHABP was over twice as high when treated with meropenem compared with ceftolozane/tazobactam.

Trial registration

clinicaltrials.gov, NCT02070757. Registered 25 February, 2014, clinicaltrials.gov/ct2/show/NCT02070757.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13054-021-03694-3.

Daptomycin for Complicated Skin Infections: A Randomized Trial

BACKGROUND

Complicated skin and skin structure infections (cSSSI) are common in children. Due to safety and resistance issues with recommended agents, new treatment options would be advantageous.

METHODS

Multicenter, evaluator-blinded clinical trial. Patients 1 to 17 years old with cSSSI caused by Gram-positive pathogens were randomized 2:1 to intravenous daptomycin or standard-of-care (SOC) treatment for ≤14 days. Daptomycin was administered once daily with dosing by patient age: 12 to 17 years, 5 mg/kg; 7 to 11 years, 7 mg/kg; 2 to 6 years, 9 mg/kg; 12 to 23 months, 10 mg/kg. The primary objective was to evaluate daptomycin safety. The secondary objective was to assess the efficacy of daptomycin compared with SOC. The intent-to-treat (ITT) population consisted of all randomized patients with any dose of study drug.

RESULTS

The ITT population comprised 257 daptomycin and 132 SOC patients (primarily clindamycin or vancomycin); 35% had confirmed methicillin-resistant Staphylococcus aureus. The most common adverse events were diarrhea (7% daptomycin, 5% SOC) and increased creatine phosphokinase (6% daptomycin, 5% SOC). The proportions of safety population patients with treatment-related adverse events were similar between the daptomycin (14%) and SOC (17%) groups. Clinical success rates (blinded evaluator-assessed complete/partial resolution of cSSSI signs and symptoms 7-14 days after end-of-treatment) in the ITT population were also similar for the daptomycin (91%) and SOC groups.

CONCLUSIONS

Once-daily daptomycin was well tolerated, with safety and efficacy comparable to SOC in children/adolescents with cSSSI caused by Gram-positive pathogens, including community-acquired methicillin-resistant S aureus.

Heparin-induced thrombocytopenia and thrombosis: presentation after cardiopulmonary bypass

Heparin-induced thrombocytopenia and thrombosis syndrome was diagnosed in a 63-year-old woman 11 days after coronary artery bypass grafting. Her only presenting complaints were incisional leg pain and vague chest discomfort. The syndrome was suspected when her platelet count was found to be 37,000/microL. A subsequent ventilation-perfusion lung scan showed findings highly probable for pulmonary embolism. An inferior venacavogram obtained before a pulmonary angiogram revealed a large retrohepatic thrombus at the right atrial junction. The patient was successfully treated with the defibrinogenating agent ancrod (Arvin). A diagnosis of heparin-induced thrombocytopenia and thrombosis syndrome should be considered and heparin therapy should be avoided in patients with low platelet counts who have been previously treated with heparin.

Lentigo maligna. The use of rush permanent sections in therapy

Lentigo maligna is often treated with superficial therapies that are associated with high recurrence rates. The high recurrence rates are a result of incomplete destruction or removal of tumor from clinically inapparent but histologically positive areas. We describe the use of the Mohs technique with rush permanent sections for the complete removal of this melanocytic neoplasm.

Melphalan and prednisone plus total bone marrow irradiation as initial treatment for multiple myeloma

Patients who have received radiation to localized areas of marrow eventually regenerate marrow in the irradiated area, if the dose is 2,400 centigrays (cGy) or less. This trial was designed to deliver a radiation dose of 1500 cGy to all marrow containing sites in patients with multiple myeloma, a technique we refer to as total bone marrow irradiation, or TBMI. Patients with previously untreated myeloma received 12 weeks of melphalan (L-PAM) and prednisone (pred) therapy. Four weeks later, sequential irradiation was administered using the 3-2 technique with rest periods to permit recovery from radiation-induced cytopenia. This was followed by electron beam irradiation of the rib and skull fields. Following completion of TBMI, patients were untreated until relapse. Twenty patients were entered. At entry 5, 8, and 7 patients had low, intermediate and high tumor cell loads, respectively. Two patients had a serum Ca in excess of 12 mg/dl; 3 had an increased creatinine. The median performance (ECOG) was 1. At week 16, immediately prior to TBMI, 5 of the 20 patients fulfilled the Myeloma Task Force criteria for response and 5 others had improved. Six patients did not begin the radiation therapy portion of the protocol. Three had rapidly progressive disease, one persistent leukopenia, one refused radiation therapy and one was withdrawn by his physician. Only 6 of the fourteen patients receiving the radiation treatment phase of the protocol were able to tolerate the intended course of 1500 cGy to all areas. Eight other patients received lower doses. Patients completing the radiation phase of the protocol failed to have further reductions in M-protein or improvement in other parameters beyond those obtained on the chemotherapy phase of the protocol. The median duration of response and survival was 12.0 and 42 months, respectively. We suggest possible reasons for the disappointing results of this trial and conclude that this approach to the primary treatment of myeloma holds little promise.

Surgical margins for basal cell carcinoma

Basal cell carcinomas frequently extend beyond their visible borders. Therefore, the goal of surgical therapy must be to eradicate both the clinically apparent tumor and its microscopic extension into the surrounding normal-appearing skin. This entails excising the tumor along with a margin of clinically normal skin. Unfortunately, there is no agreement as to the optimal width of surgical margins. We therefore studied 117 cases of previously untreated, well-demarcated basal cell carcinoma. Prior to excision, the normal-appearing skin surrounding the tumor was marked in 2-mm increments. The tumor was then excised using Mohs micrographic surgery. The extent of the subclinical tumor invasion was calculated from the presurgical skin markings. For tumors with a diameter less than 2 cm, a minimum margin of 4 mm was necessary to totally eradicate the tumor in more than 95% of cases.

Analysis of deuterium labeled blood lipids by chemical ionization mass spectrometry

A quantitative analytical method has been developed to analyze methyl esters of blood fatty acids derived from human subjects fed deuterium-labeled fats. The GCMS computer method provides for the analysis of the fed deuterium-labeled fatty acids, the naturally occurring blood fatty acids and new fatty acids formed by chain elongation or shortening of the fed labeled fats. Approximately 20 fatty acids including 16, 17, 18 and 20 carbon chain acids were analyzed with a relative standard deviation of 0.02 at the microgram level and a sensitivity of less than one nanogram. The method uses capillary GC to separate the fatty acid esters and isobutane chemical ionization mass spectrometry with multiple ion detection to determine the isotopic constituents of the GC peaks. The technique provides for the determination of overlapping GC peaks labeled with 2, 4 and 6 deuterium atoms and makes extensive use of computers both for data acquisition and processing.

Mott cells in a patient with a lymphoproliferative disorder. Differentiation of a clone of B lymphocytes into Mott cells

An unusual lymphoproliferative disorder characterized by diffuse infiltration of the bone marrow by lymphocytes and Mott cells without other organ involvement is described. The clinical course was remarkable for a spontaneous remission. The cells infiltrating the bone marrow were predominantly lymphocytes and Mott cells. The lymphocytes stained exclusively for membrane IgM-kappa by immunofluorescence, and the Mott cells contained typical Russell bodies staining in a rim pattern for IgM-kappa. These findings suggested that the lymphocytes were differentiating into Mott cells. This was demonstrated in vitro by stimulating peripheral blood lymphocytes with mitogens. Differentiation of B lymphocytes into Mott cells containing IgM-kappa was observed. These appeared to be identical to the Mott cells found in the marrow. The Mott cells were probably nonsecretory because of the absence of a monoclonal serum immunoglobulin. Electron microscopic studies showed that the electron-dense cytoplasmic inclusions resembled Russell bodies. This case probably represents an expanded clone of B lymphocytes with demonstrable in vivo and in vitro differentiation into Mott cells.

Autoimmune hemolytic anemia with predominance of IgA autoantibody

A 71-year-old woman with severe autoimmune hemolytic anemia had negative direct antiglobulin tests using commercial broad spectrum antisera. Her unwashed cells agglutinated spontaneously in the potentiating medium polyvinylpyrrolidone (PVP) solution or in hexadimethrine bromide (Polybrene) solution. A strongly positive direct antiglobulin test was obtained with specific antihuman IgA sea with or without PVP. In PVP solution, small amounts of IgG, IgM, and complement components were also detected on her cells. The findings illustrate the ability of anti-human IgA to detect autoimmune red blood cell sensitization when other immunoglobulin classes of autoantibody are below detectable levels or absent. Also illustrated is the value of PVP and Polybrene in detecting agglutination in the evaluation of "antiglobulin negative" hemolytic anemia.

Aggressive plasma cell myeloma. A terminal phase

Seven patients with plasma cell myeloma experienced an aggressive, terminal phase. This phase is characterized by rapidly enlarging soft-tissue masses with tumor morphologic characteristics similar to a poorly differentiated or large-cell (histiocytic) lymphoma, with rapid death, and often with fever, pancytopenia, decreasing levels of myeloma protein, and younger age. Median survival from the onset of the phase was four months. There was no response to single-agent or combination chemotherapy. In view of the extremely poor prognosis and lack of response to conventional treatment, patients experiencing this characteristic terminal phase should be considered candidates for innovative therapy.

Response of babesiosis to pentamidine therapy

Three nonsplenectomized patients were infected with Babesia microti. One had fever, abdominal pain suggesting gallbladder disease, and evidence of disseminated intravascular coagulation; another was considered to have lymphoma, partly because two smears for Babesia before admission were negative. All three patients were treated with pentamidine isethionate and improved clinically. Parasites were no longer seen on smears after 5 days of therapy, but Babesia could still be recovered by hamster inoculation 5 weeks after therapy in one of the patients tested, underscoring the need for this test to properly evaluate eradication of the organism. In one patient, pentamidine was stopped after 7 days because of increased creatinine concentration, and this amount of drug appeared adequate to control the parasitemia. Pain at drug injection sites was a major side effect in all three patients. Pentamidine appears to be useful in controlling clinical manifestations of babesiosis and decreasing parasitemia, but it does not eradicate the organism.

Unusual intracytoplasmic inclusions in acute myeloblastic leukemia

Unusual intracytoplasmic inclusions within early granulocyte precursor cells from a patient with acute myeloblastic leukemia (AML) are described. Based upon their staining characteristics and electron- and light-microscopic appearance, the inclusions are distinctly different from any previously described. The inclusions display a variety of shapes, including rectangles, squares, circles, ovals, and irregular, globular forms. Most of the inclusions are refractile and crystal-like. The possible composition of these inclusions is discussed. They are compared with inclusions previously described within leukemic and granulocytic cells.

Mass spectrometric analysis of deuterium dual labeled blood lipids

A gas chromatography selected ion monitoring mass spectrometer technique was developed to analyze deuterium dual labeled blood lipid samples from a human feeding experiment. In the metabolism experiment, described elsewhere. [2H2] labeled cis and [2H4] labeled trans fatty acids were fed to a human sujbect as a single pulse in order to determine whether the human body differentiates between cis and trans fatty acids in the diet. The analytical method described here was developed to accurately measure the ratio of [2H2]methyl oleate to [2H4]methyl elaidate in the presence of large amounts of [2H0] methyl oleate in samples derived from separated fractions of blood lipids. The technique is different from most selected ion monitoring methods in that the internal standard was fed to the subject along with the experimental material; the samples contained large amounts of unlabeled material chemically identical to the labeled material and the ratio of [2H2] to [2H4] fatty esters was of principal interest rather than the absolute value. Nine standards were analyzed eight or more times to form a basis for statistical evaluation of the method. Analysis of the plasma phosphatidyl ethanolamine fraction from the metabolic experiment is given as an example.

Splenectomy in chronic myeloid leukemia

We review splenectomy in chronic myeloid leukemia, emphasizing recent studies that have evaluated early splenectomy during the chronic phase of the disease. Despite current interest in splenectomy in chronic myeloid leukemia, uncontrolled clinical trials to date suggest that the operation during the early phase neither delays the onset of blastic transformation nor prolongs survival. Immediate operative mortality of splenectomy during the chronic phase is low, generally less than 1%. The morbidity of the procedure, however, remains formidable due to infectious and thromboembolic complications. Splenectomy during chronic-phase chronic myeloid leukemia permits easier control of the disease in patients who are thrombocytopenic due to busulfan toxicity or sensitivity. Splenectomy during the chronic phase may also palliate those patients who suffer from acute splenic events or massive splenomegaly. Splenectomy in blast-phase disease should be considered a heroic measure providing little benefit to most patients.

Factors associated with prolonged survival in chronic myeloid leukemia

Four patients who demonstrated unusually prolonged survival with Philadelphia chromosome positive Ph' (+) chronic myeloid leukemia (CML) were analyzed for factors associated with survival. Survival duration from initial diagnosis ranged from 120 to 222 months, with a mean of 170 months. At diagnosis, age, symptoms, liver or spleen size, hematocrit, white blood cell count, absolute peripheral myeloblast plus promyelocyte count, and uric acid did not have unique prognostic significance. At diagnosis all four patients had normal or low-normal platelet counts, (range: 170,000 to 248,000/mm3). Thrombocytopenia occurred during treatment in three patients. None of the four patients, however, developed severe marrow hypoplasia or leukopenia during treatment for the chronic phase. Cytogenic studies performed from 103 to 156 months after diagnosis did not reveal a large subpopulation of marrow cells with a normal karyotype or cells with the XO genotype in the male patients. These observations suggest that prolonged survival in CML 1) is not contingent upon intensive treatment resulting in marrow hypoplasia, and 2) does not require the persistence of a clone of karyotypically-normal bone marrow cells or a clone of marrow cells in males which has lost the Y chromosome. A normal or low-normal platelet count at diagnosis may be a favorable prognostic indicator.

Herpetic esophagitis in patients with cancer: ante mortem diagnosis by brush cytology

Ante mortem diagnosis of herpetic esophagitis has been made in four immunosuppressed patients with cancer. The diagnosis was made by brush cytology at the time of esophagoscopy. All four patients had severe dysphagia unresponsive to nystatin therapy and the diagnosis of herpes infection excluded the use of Amphotericin B for resistant moniliasis. The diagnosis of herpes virus infection of the esophagus has been previously made almost exclusively at post mortem examination. Herpetic esophagitis is shown to be not necessarily a preterminal complication in cancer patients. In three of the four patients the esophagitis resolved as the patients responded to anti-tumor therapy.