The emerging problem of bacterial resistance in cancer patients; proceedings of a workshop held by MASCC "Neutropenia, Infection and Myelosuppression" Study Group during the MASCC annual meeting held in Berlin on 27-29 June 2013

Eltrombopag Improves Erythroid Differentiation in a Human Induced Pluripotent Stem Cell Model of Diamond Blackfan Anemia

Diamond Blackfan Anemia (DBA) is a congenital macrocytic anemia associated with ribosomal protein haploinsufficiency. Ribosomal dysfunction delays globin synthesis, resulting in excess toxic free heme in erythroid progenitors, early differentiation arrest, and pure red cell aplasia. In this study, DBA induced pluripotent stem cell (iPSC) lines were generated from blood mononuclear cells of DBA patients with inactivating mutations in RPS19 and subjected to hematopoietic differentiation to model disease phenotypes. In vitro differentiated hematopoietic cells were used to investigate whether eltrombopag, an FDA-approved mimetic of thrombopoietin with robust intracellular iron chelating properties, could rescue erythropoiesis in DBA by restricting the labile iron pool (LIP) derived from excessive free heme. DBA iPSCs exhibited RPS19 haploinsufficiency, reduction in the 40S/60S ribosomal subunit ratio and early erythroid differentiation arrest in the absence of eltrombopag, compared to control isogenic iPSCs established by CRISPR/Cas9-mediated correction of the RPS19 point mutation. Notably, differentiation of DBA iPSCs in the presence of eltrombopag markedly improved erythroid maturation. Consistent with a molecular mechanism based on intracellular iron chelation, we observed that deferasirox, a clinically licensed iron chelator able to permeate into cells, also enhanced erythropoiesis in our DBA iPSC model. In contrast, erythroid maturation did not improve substantially in DBA iPSC differentiation cultures supplemented with deferoxamine, a clinically available iron chelator that poorly accesses LIP within cellular compartments. These findings identify eltrombopag as a promising new therapeutic to improve anemia in DBA.

Molecular Characterization of Carbapenemase-Producing Klebsiella pneumoniae Isolated from Egyptian Pediatric Cancer Patients Including a Strain with a Rare Gene-Combination of β-Lactamases

PURPOSE

Healthcare-associated infections caused by multi-drug-resistant (MDR) pathogens are a global threat. We aim to assess the clonal relatedness among carbapenemase-producing Klebsiella pneumoniae (CPKP) strains infecting Egyptian pediatric cancer patients.

MATERIALS AND METHODS

Identification and antimicrobial susceptibility testing of 149 Gram-negative isolates obtained from pediatric cancer patients were performed by VITEK 2. Genes encoding carbapenemases and extended-spectrum β-lactamases were detected by PCR and verified by DNA sequencing of representative samples. The transferability of the plasmids harboring bla OXA-48, from representative clinical samples, was evaluated by performing a conjugation experiment followed by PCR and MIC shift determination. Clonal relationships among the bla OXA-48-harboring K. pneumoniae isolates were determined by enterobacterial repetitive intergenic consensus (ERIC)-PCR and pulsed-field gel electrophoresis (PFGE).

RESULTS

Carbapenem resistance was observed in 59% of the isolates. The most prevalent species was K. pneumoniae (45.6%) and 57% of them were isolated from ICU. Fifty-nine % of the K. pneumoniae isolates were carbapenemase-producers and bla OXA-48 was detected in (58%) of them. One isolate co-harbored bla OXA-48, bla NDM-1, and bla IMP-1 genes for the first time in Egypt. PCR and meropenem MIC shift confirmed the success of the transferability of representative plasmids to E. coli K12. ERIC and PFGE identified 93% and 100% of the K. pneumoniae with a similarity coefficient ≥85%, respectively, including strains with indistinguishable patterns, suggesting possible clonal dissemination.

CONCLUSION

Our findings underline the dissemination of diverse clones of MDR CPKP among Egyptian pediatric cancer patients. Hence, routine molecular characterizations followed by strict implementation of infection control measures are crucial to tackling this threat.

Emerging challenges in the evaluation of fever in cancer patients at risk of febrile neutropenia in the era of COVID-19: a MASCC position paper

Patients with cancer are at higher risk of more severe COVID-19 infection and have more associated complications. The position paper describes the management of cancer patients, especially those receiving anticancer treatment, during the COVID-19 pandemic. Dyspnea is a common emergency presentation in patients with cancer with a wide range of differential diagnoses, including pulmonary embolism, pleural disease, lymphangitis, and infection, of which SARS-CoV-2 is now a pathogen to be considered. Screening interviews to determine whether patients may be infected with COVID-19 are imperative to prevent the spread of infection, especially within healthcare facilities. Cancer patients testing positive with no or minimal symptoms may be monitored from home. Telemedicine is an option to aid in following patients without potential exposure. Management of complications of systemic anticancer treatment, such as febrile neutropenia (FN), is of particular importance during the COVID-19 pandemic where clinicians aim to minimize patients' risk of infection and need for hospital visits. Outpatient management of patients with low-risk FN is a safe and effective strategy. Although the MASCC score has not been validated in patients with suspected or confirmed SARS-CoV-2, it has nevertheless performed well in patients with a range of infective illnesses and, accordingly, it is reasonable to expect efficacy in the clinical setting of COVID-19. Risk stratification of patients presenting with FN is a vital tenet of the evolving sepsis and pandemic strategy, necessitating access to locally formulated services based on MASCC and other national and international guidelines. Innovative oncology services will need to utilize telemedicine, hospital at home, and ambulatory care services approaches not only to limit the number of hospital visits but also to anticipate the complications of the anticancer treatments.

Antibiotic use during cytarabine consolidation in acute myeloid leukemia

Acute myeloid leukemia (AML) patients undergoing consolidation chemotherapy with intermediate or high-dose cytarabine (IDAC/HiDAC) are often placed on prophylactic antibacterials. This practice is largely based on the benefits of prophylaxis (PPX) during induction chemotherapy. However, recent concerns regarding antibacterial prophylaxis have emerged including risk of Clostridioides difficile colitis, medication toxicities, and the potential for fostering multidrug-resistant pathogens. We therefore retrospectively explored whether antibacterial PPX is beneficial during cytarabine consolidation. Adult AML patients who received IDAC/HiDAC at our institution from January 2007 to March 2018 were evaluated for receipt of antibacterial PPX. The primary endpoint was rate of febrile neutropenia (FN); secondary endpoints were rates of unplanned hospitalization, bacteremia, infection from resistant organisms, C. difficile colitis, and death from infection. One hundred twenty patients with data from 229 IDAC/HiDAC cycles were included. Patients who received antibacterial PPX were more often hospitalized during cytarabine cycle 1 (C1) than those who received no PPX. Patients who received PPX had significantly more episodes of bacteremia, in addition to infections from resistant, predominantly Gram-positive organisms during cycle 1 of consolidation than those without PPX. Antibacterial PPX during IDAC/HiDAC consolidation treatment at our institution did not decrease the rates of FN, hospitalization, or bacteremia and was associated with higher risk of infection from drug-resistant bacteria in C1. Prospective studies examining antibacterial prophylaxis during cytarabine consolidation for AML patients are necessary, with strong consideration made for institution-specific protocols.

Activity of Cefiderocol and Comparators against Isolates from Cancer Patients

Cefiderocol inhibited 97.5% of 478 Gram-negative isolates from cancer patients at ≤4 mg/liter. It had potent activity against extended-spectrum β-lactamase-positive Enterobacteriaceae, carbapenem-resistant Enterobacteriaceae (CRE), and nonfermenting Gram-negative bacilli, including Pseudomonas aeruginosa, Stenotrophomonas maltophilia, and Acinetobacter species isolates. Amikacin, ceftazidime-avibactam, and meropenem had appreciable activity against non-CRE Enterobacteriaceae No comparators were active against multidrug-resistant P. aeruginosa isolates. Only trimethoprim-sulfamethoxazole had appreciable activity against S. maltophilia isolates. Overall, cefiderocol was associated with the lowest level of resistance.

High Prevalence of Antibiotic-Resistant Otitis Media-Associated Bacterial Flora of Asymptomatic People Living with HIV at Morogoro Hospital, Tanzania

OBJECTIVES

The study aimed to determine the prevalence of otitis media (OM)-associated bacterial flora of asymptomatic people living with HIV (PLH) on antiretroviral therapy (ART) and assess antibiotic resistance profiles of the bacteria.

METHODOLOGY

Ear secretion specimens were collected by syringe or cotton swabs. Isolated bacteria were subjected to antibiotic sensitivity tests.

RESULTS

Of 290 recruited PLH, 81.7% were females and 18.3% males; their CD4+ counts ranged from 0 to 1770. Staphylococcus aureus, Klebsiella pneumonia, and Escherichia coli were the predominant bacteria. High antibiotic resistance was detected on Streptococcus pyogenes and Streptococcus pneumoniae. The prevalence rate of OM-associated bacteria (OAB) was 93.4%, and majority of the bacteria were resistant to multiple antibiotics. Linear association between the prevalence of OAB with both duration of ART and CD4+ counts was observed.

CONCLUSION

High prevalence rates of OAB and antibiotic resistance were observed. Negative correlation between CD4+ counts and prevalence of OAB was revealed.

Antimicrobial Activities of Ceftazidime-Avibactam and Comparator Agents against Clinical Bacteria Isolated from Patients with Cancer

A total of 521 unique clinical isolates from cancer patients with primarily (>90%) bloodstream infections were tested for susceptibility to ceftazidime-avibactam and comparators using broth microdilution methods. Ceftazidime-avibactam inhibited 97.8% of all Enterobacteriaceae (n = 321) at the susceptibility breakpoint of ≤8/4 μg/ml (there were 7 nonsusceptible strains). It was also active against Pseudomonas aeruginosa (91.7% isolates susceptible, n = 121), including many isolates not susceptible to meropenem, cefepime, ceftazidime, piperacillin-tazobactam, or other comparators.