Genomic characterization of Klebsiella pneumoniae carbapenemase-producing Klebsiella pneumoniae (KPC-Kp) strains circulating in three university hospitals in Northern Italy over three years.

OBJECTIVES: Genomic surveillance of Klebsiella pneumoniae carbapenemase-producing Klebsiella pneumoniae (KPC-Kp) is crucial for virulence, drug-resistance monitoring, and outbreak containment. METHODS: Genomic analysis on 87 KPC-Kp strains isolated from 3 Northern Italy hospitals in 2019-2021 was performed by whole genome sequencing (WGS), to characterize resistome, virulome, and mobilome, and to assess potential associations with phenotype resistance and clinical presentation. Maximum Likelihood and Minimum Spanning Trees were used to determine strain correlations and identify potential transmission clusters. RESULTS: Overall, 15 different STs were found; the predominant ones included ST307 (35, 40.2%), ST512/1519 (15, 17.2%), ST20 (12, 13.8%), and ST101 (7, 8.1%). 33 (37.9%) KPC-Kp strains were noticed to be in five transmission clusters (median number of isolates in each cluster: 5 [3-10]), four of them characterized by intra-hospital transmission. All 87 strains harbored Tn4401a transposon, carrying blaKPC-3 (48, 55.2%), blaKPC-2 (38, 43.7%), and in one case (1.2%) blaKPC-33, the latter gene conferred resistance to ceftazidime/avibactam (CZA). Thirty strains (34.5%) harbored porin mutations; of them, 7 (8.1%) carried multiple Tn4401a copies. These strains were characterized by significantly higher CZA minimum inhibitory concentration compared with strains with no porin mutations or single Tn4401a copy, respectively, even if they did not overcome the resistance breakpoint of 8 ug/mL. Median 2 (IQR:1-2) virulence factors per strain were detected. The lowest number was observed in ST20 compared to the other STs (p<0.001). While ST307 was associated with infection events, a trend associated with colonization events could be observed for ST20. CONCLUSIONS: Integration of genomic, resistance score, and clinical data allowed us to define a relative diversification of KPC-Kp in Northern Italy between 2019 and 2021, characterized by few large transmission chains and rare inter-hospital transmission. Our results also provided initial evidence of correlation between KPC-Kp genomic signatures and higher MIC levels to some antimicrobial agents or colonization/infection status, once again underlining WGS's importance in bacterial surveillance.

Microbial composition associated with biliary stents in patients undergoing pancreatic resection for cancer.

Malignant bile duct obstruction is typically treated by biliary stenting, which however increases the risk of bacterial infections. Here, we analyzed the microbial content of the biliary stents from 56 patients finding widespread microbial colonization. Seventeen of 36 prevalent stent species are common oral microbiome members, associate with disease conditions when present in the gut, and include dozens of biofilm- and antimicrobial resistance-related genes. This work provides an overview of the microbial communities populating the stents.

Familial breast cancer: characteristics and outcome of BRCA 1-2 positive and negative cases.

BACKGROUND: The clinical and pathological characteristics and the clinical course of patients with breast cancer and BRCA 1-2 mutation are poorly known. METHODS: From 1997, patients with breast cancer and a family history of breast or ovarian cancer were offered BRCA testing. The clinical and pathological features of patients with known BRCA status were retrospectively assessed and comparisons were made between cancers arising in BRCA positive and BRCA wild type (WT) patients respectively. Type of treatment, pattern of relapse, event (local relapse, contralateral breast cancer, metastases) free and overall survival were also compared in the two groups. Out of the 210 patients tested, 125 had been treated and followed-up at our Institution and were evaluated in this study. RESULTS: BRCA positive patients tended to be more often premenopausal (79% vs 65%) and to have positive lymphnodes (63% vs 49%), poorly differentiated tumours (76% vs 40%--p = 0.002 at univariate analysis, not significant at multivariate analysis) and negative estrogen receptors (43% vs 29%). Treatment was not different in the two groups. In the 86 BRCA-WT patients, the first event was a local relapse in 3 (3%), metachronous contralateral breast cancer in 7 (8%) and distant metastases in 16 (19%). In the 39 BRCA positive patients, the corresponding figures were 3 (8%), 8 (21%) and 3 (8%). There was no difference in event free survival, with a median of 180 months in both groups of patients. At 20 years, projected survival was 85% for BRCA positive patients and 55% for BRCA-WT, but this difference was not statistically significant. CONCLUSION: Although BRCA positive patients have more frequently negative prognostic factors, their prognosis appears to be equal to or better than in patients with BRCA-WT.

Breast cancer and pregnancy.

The diagnosis of breast cancer during pregnancy is a rare event, but the young age of the patient together with the emotional impact for both the family and the doctors make therapeutic choices usually very difficult. Until recently, the occurrence of pregnancy associated breast cancer was thought to hold a grave prognosis and therapeutic abortion was very often advised in common practice. The hormonal environment with the increase in estrogens and progesterone was the main factor for the fear of tumor stimulation. The course of breast cancer, however, does not appear to be adversely affected by continuation of pregnancy. In the last years it was realized that potentially curative therapies can be administered even when pregnancy is continued. Of course in the medical literature there is no randomized clinical trial helping in taking decision in this setting; however, a significant experience already exists in some institutions and can guide management in these difficult cases. The aim of our review is to give an answer to questions usually coming from various specialists who collaborate with the oncologists in treating these patients and furthermore to try and find some basic guidelines which can be used in the information of the patients regarding previous experience in this field. The problem of a pregnancy after treatment for breast cancer is also analyzed, as this aspect is an emerging issue in clinical oncology. The decision should be evaluated for each single patient, taking into account the prognosis of the patient and her desire of pregnancy.

Acceptance of external infusion pumps in patients with advanced breast cancer receiving continuous infusion fluorouracil.

BACKGROUND: We investigated the physical and psychological adaptation to a protracted continuous infusion system in a series of patients receiving protracted continuous infusion of 5-fluorouracil for advanced breast cancer. PATIENTS AND METHODS: The protracted continuous infusion of 5-fluorouracil was administered by means of a portable elastomeric pump (Baxter Seven-Day Infusor, 0.5 mL/hr) via an indwelling Groshong catheter. Patients were asked to complete a questionnaire exploring the impact of the continuous infusion system upon various aspects of daily life, the overall level of disturbance, the general judgement on its quality, and their willingness to resume the same kind of treatment in the future. All items were graded on a 4-point scale from 0 = not at all, to 4 = very much. RESULTS: Seventy-one patients were evaluated. All patients received 5-fluorouracil at the dose of 250 mg/m2/day as a protracted continuous infusion alone (n = 14) or in combination with vinorelbine (n = 45) or Taxol (n = 12). The median duration of the protracted continuous infusion before evaluation was 9 months (3-31). The mean level of disturbance to daily activities was 0.86 points. The activities most frequently disturbed by treatment included daily personal care (mean, 1.76 points) and sexual activity (mean, 1.20 points). Twenty-one patients required medical intervention because of problems related to the protracted continuous infusion system. The overall level of disturbance was rated at a mean level of 0.72 points, whereas the overall merits of the protracted continuous infusion system and the willingness of the patient to resume protracted continuous infusion in the future were rated at a mean level of 2.90 and 2.55 points, respectively. CONCLUSIONS: The system for the protracted continuous infusion of 5-fluorouracil was well tolerated by the patients, who were able in most cases to perform their daily activities with little or no disturbance, needing only occasional help, and were willing to resume the same treatment modality if necessary.

Long-term, weekly one-hour infusion of paclitaxel in patients with metastatic breast cancer: a phase II monoinstitutional study.

AIMS AND BACKGROUND: A dose-dense therapy with weekly paclitaxel given as a 1-hr infusion yielded a 53% overall response rate in breast cancer patients resistant to anthracyclines, with a remarkable lack of neutropenia (Seidman, 1998). We performed a monoinstitutional phase II trial in order to confirm these interesting results. PATIENTS AND METHODS: Eligibility criteria included advanced breast cancer and no taxane pretreatment. Paclitaxel was administered weekly at the dose of 90 mg/m2 (60 mg/m2 in patients at high risk of toxicity) by 1-hr i.v. infusion. Fifty-eight patients entered the trial. Median age was 54 years (range, 38-72). Performance status was good (median 1; range, 0-2). Fifty-two patients were pretreated with anthracyclines. RESULTS: A total of 1,004 weekly paclitaxel infusions were administered (median, 19 per patient; range, 4-43). The median delivered dose intensity was 67.4 mg/m2/week (range, 43-86). Twenty-eight of the 58 assessable patients obtained an objective response (48%), 15 had stable disease (26%) and 15 progressed (26%). The overall response rate was 48% (95% confidence interval, 35-61%) with 5 complete responses (8%). In anthracycline-pretreated patients, 23/52 (44%) responses were observed. Median duration of response was 5 months (range, 3-27). Toxicity was acceptable apart from a case of pulmonary embolism in a 70-year-old patient, 1 case of congestive heart failure in an anthracycline-pretreated patient aged 64, and 9 cases of G3 neutropenia. Peripheral neuropathy was observed in 38 patients (64%), usually of a mild grade; alopecia in 45 patients (78%) and onychopathy in 16 (28%), usually of a mild grade apart from 2 cases requiring treatment interruption. Tachycardia and atrial fibrillation occurred in a 55-year-old woman. CONCLUSIONS: Our data seem to confirm the activity and safety of this approach even in a heavily pretreated population of patients. Its combination with other active drugs needs to be further investigated in clinical trials.

Heteroresistance to glycopeptides in Italian meticillin-resistant Staphylococcus aureus (MRSA) isolates.

The prevalence and molecular characterisation of heteroresistant vancomycin-intermediate Staphylococcus aureus (hVISA) strains were determined in a large group of Italian strains isolated between 2005 and mid 2007. Amongst the 1284 strains isolated from documented infections in hospitalised patients (bloodstream infection, pneumonia, and skin and skin-structure infections), 139 S. aureus with vancomycin minimum inhibitory concentrations (MICs) between 1 mg/L and 2 mg/L were screened for the presence of hVISA using three different methods and were confirmed by population analysis profile (PAP). Thirty-six hVISA strains (25.9%) were detected. Amongst the three screening methods used, the macro Etest (MET) demonstrated 100% specificity and 75% sensitivity. hVISA strains were accessory gene regulator (agr) types I and II and belonged to the major nosocomial clones circulating in Italy (ST8, ST239, ST247 and ST228). All strains were susceptible to quinupristin/dalfopristin, linezolid, daptomycin, tigecycline and dalbavancin. In conclusion, we have demonstrated that hVISA isolates are common amongst MRSA isolates with MICs between 1 mg/L and 2 mg/L in Italy. MET, with its high sensitivity and specificity, should be used for early detection of hVISA, especially in patients with serious or prolonged infections sustained by MRSA. Finally, the most recent anti-Gram-positive drugs maintained their full spectrum of in vitro activity against these strains.