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.

Quantitative Chest CT Analysis to Measure Short-Term Sequelae of COVID-19 Pneumonia: A Monocentric Prospective Study.

(1) Background: Quantitative CT analysis (QCT) has demonstrated promising results in the prognosis prediction of patients affected by COVID-19. We implemented QCT not only at diagnosis but also at short-term follow-up, pairing it with a clinical examination in search of a correlation between residual respiratory symptoms and abnormal QCT results. (2) Methods: In this prospective monocentric trial performed during the "first wave" of the Italian pandemic, i.e., from March to May 2020, we aimed to test the relationship between %deltaCL (variation of %CL-compromised lung volume) and variations of symptoms-dyspnea, cough and chest pain-at follow-up clinical assessment after hospitalization. (3) Results: 282 patients (95 females, 34%) with a median age of 60 years (IQR, 51-69) were included. We reported a correlation between changing lung abnormalities measured by QCT, and residual symptoms at short-term follow up after COVID-19 pneumonia. Independently from age, a low percentage of surviving patients (1-4%) may present residual respiratory symptoms at approximately two months after discharge. QCT was able to quantify the extent of residual lung damage underlying such symptoms, as the reduction of both %PAL (poorly aerated lung) and %CL volumes was correlated to their disappearance. (4) Conclusions QCT may be used as an objective metric for the measurement of COVID-19 sequelae.

Outcomes of patients with unexpected diagnosis of infection at total hip or total knee arthroplasty revisions.

PURPOSE: The pre-operative differential diagnosis between periprosthetic joint infections (PJIs) and aseptic failure is challenging particularly in low virulence and biofilm-related infections. This study aimed to assess the incidence and survival of patients with unexpected PJIs in a presumed aseptic revision of total hip (THA) and knee (TKA) arthroplasties. METHODS: A retrospective analysis of a prospective cohort of patients was performed with 295 patients undergoing THA (n = 241) or TKA (n = 54) revision for presumed aseptic causes. Patients were diagnosed with unexpected PJI taking into account leukocyte count in the synovial fluid, sonicate, synovial culture, and tissue cultures of samples collected during surgery. The primary endpoint was the infection-free implant survival rate at theone year follow-up. RESULTS: The unexpected PJIs were 60 out of 295 (20.3%), whereas 235 (79.7%) were aseptic revisions. In the unexpected PJI group, 6 (11.1%) patients underwent knee revision and 54 (22.4%) hip revision. At the one year follow-up, one patient (1.6%) in the unexpected PJI group and 3 (1.3%) in the aseptic group (p = 1.0) failed for infection. The infection-free implant survival rate at the one year follow-up was 98.3% (C.I. 95%, 94.9-99.9%) for the unexpected PJI group and 98.7% (C.I. 95%, 97.3-99.9%) (p = 0.82) for the aseptic group. CONCLUSION: The incidence of unexpected PJIs in a presumed aseptic revision of THAs and TKAs has been previously underestimated. The infection-free implant survival rate at the one year follow-up in patients with unexpected PJIs was not significantly lower compared with patients undergoing aseptic revision.

Sudden cardiac death in a young HIV-positive man on effective antiretroviral therapy.

We describe the case of a young HIV-positive man on effective HAART with excellent viro-immunological control who presented a massive cardiac infarction. Despite the presence of clinical risk factors for cardiovascular disease, the patient had normal arterial carotid IMT values, known to be strong predictors of atherosclerosis and stroke. Interestingly, parameters of T-cell activation (CD8+CD38+) were shown to increase just before the onset of myocardial infarction. As T-cell activation is known to mediate atherosclerosis, the authors suggest that surrogate immunologic markers should be identified to better assess cardiovascular risk in the setting of HIV infection.

Non-invasive markers of liver fibrosis in HCV mono-infected and in HIV/HCV co-infected subjects.

Non-invasive markers of liver fibrosis have been recently developed as a possible alternative to liver biopsy. The clinical management of hepatic diseases is dependent on the extent of liver fibrosis. Liver biopsy remains the gold standard but severe complications are found in about 0.5% of cases. Studies involving sequential liver biopsies are impractical, costly, and risky. Therefore non-invasive markers of liver fibrosis could be useful. These drawbacks justify an intensive research on non-invasive alternatives. Several serum markers are either directly involved in fibrosis remodelling or are indirectly associated with the presence of significant liver fibrosis. More recently, fibrosis scores calculated from statistical models have been described. This review describes the role of non-invasive markers in assessing hepatic fibrosis in both HCV mono-infected and HIV/HCV co-infected subjects.

Hepatitis B vaccination in HIV-infected subjects.

Subjects at risk of infection with human immunodeficiency virus (HIV) are also at high risk of acute and chronic hepatitis B virus (HBV) infection. HIV is associated with higher HBV viraemia and with the risk of HBV reactivation, chronic active HBV infection, cirrhosis and death. Therefore, hepatitis B vaccination is recommended for all HIV-infected subjects lacking prior immunity. However, the immune response to hepatitis B vaccine is frequently suboptimal in this population. High CD4+ cell counts and low HIV viraemia are well known factors associated with a better rate of response. Moreover, higher hepatitis B vaccine doses and/or prolongation of the vaccination schedule, as implemented for patients with immune deficiencies other than HIV, may be considered. New vaccination cycles should be considered if post-vaccination titers of antibodies to hepatitis B surface antigen are < 10 mIU/mL (< 10 UI/L). The immunization of all young and middle-aged adults appears to be the most useful strategy to protect all patient-populations at high risk of sexually transmitted diseases.

Long-term immunologic outcome in HAART-experienced subjects receiving lopinavir/ritonavir.

The long-term immunological efficacy of regimens including lopinavir/ritonavir (LPV/r) has not been assessed in HIV-infected HAART-experienced subjects. The present study included 452 consecutive HIV-infected outpatients starting LPV/r before May 2003 after failing (HIV-RNA > 1000 copies/ml) HAART. Four groups were considered according to CD4 cell counts at LPV/r initiation: group 1 (G1, n = 115) < 100 cells/mm(3); group 2 (G2, n = 113) 100-199 cells/mm(3); group 3 (G3, n = 115) 200-349 cells/mm(3); group 4 (G4, n = 109) >/= 350 cells/mm(3). The majority of patients were males (n = 320, 70.8%), the median age was 38 years, and 180 (39.6%) were on CDC stage C. The median time of previous HAART was 51.1 months (12-81.7) and a median of 7 antiretroviral regimens and of 3 protease inhibitors was changed before LPV/r. The mean CD4 cell count increase was 105, 113, 128, and 144 cells/mm(3) after 12 months (p < 0.01 for each group) and 128, 106, 90, and 100 cells/mm(3) at month 48 (p < 0.01 for each group) in G1, G2, G3, and G4, respectively. The mean increase was comparable among the four groups. The on treatment analysis showed a better immunologic response among G1 and G2 patients from month 36. Forty-seven patients (10.4%), mainly in G1 and G2, maintained LPV/r despite persistent HIV-RNA > 1000 copies/ml. A mean increase of 64 and 65 cells/mm(3) and of 88 and 56 cells/mm(3) at month 12 and 48 was observed in G1 and G2, respectively. The use of LPV/r-based regimens also provided a durable immunologic recovery in highly pretreated HIV-infected subjects.

Subclinical hypothyroidism in HIV-infected subjects.

OBJECTIVES: The correlation between subclinical hypothyroidism [thyroid stimulating hormone (TSH)>4 mIU/L with normal free triiodothyroxine and free thyroxine levels], HIV infection and HAART is still unclear. PATIENTS AND METHODS: To evaluate the predictive factors of subclinical hypothyroidism in an HIV-infected population, we identified three groups of subjects: G1, subjects on stable highly active antiretroviral therapy (HAART) (for at least 1 year) at baseline and at month 24 (n=97); G2, subjects naive at both baseline and month 24 (n=47); G3, subjects starting HAART at baseline (n=46). RESULTS: The three groups were comparable with respect to age, gender, body weight and prevalence of HCV infection. At baseline, subclinical hypothyroidism was detected in 14 subjects in G1 (14.4%), 5 in G2 (10.6%) and 4 in G3 (8.7%) (P=0.18) and these were excluded from the analysis. At month 24, 15 subjects had developed subclinical hypothyroidism: 4 in G1 (4.8%), 3 in G2 (7.1%) and 8 in G3 (19.0%). In the multivariable analysis, the higher increase in total cholesterol was predictive of subclinical hypothyroidism (RR: 1.53 for each additional 10 mg/dL, 95% CI 1.23-1.90; P<0.01); other variables, which were statistically significant in the univariate analysis, such as G3 group, body weight and higher increase in CD4+ cell count and in triglyceride serum levels were not confirmed to be associated with TSH alterations. CONCLUSIONS: The occurrence of subclinical hypothyroidism in HIV-positive patients seems to be related to the increase in total cholesterol serum levels occurring after HAART initiation. Thyroid function should be monitored in all HIV-infected subjects, especially in those starting HAART.

Treatment interruptions in HIV-infected subjects.

Despite a high antiviral efficacy, the use of highly active antiretroviral therapy (HAART) in clinical practice is often impaired by the long-term toxicity of antiretroviral treatment, the increased rate of human immunodeficiency virus-1 (HIV-1) drug resistance in treated patients and the cost of therapies, so that possible interruption of HAART has to be considered as part of the current clinical practice. However, this strategy is usually followed by a rapid viral rebound with a substantial loss of CD4 T lymphocytes because the HIV suppression with HAART does not result in reconstitution of the HIV-specific immune response. Structured treatment interruption (STI) has already been investigated in HIV-infected subjects with well-controlled viral replication (initiating treatment during primary or chronic HIV infection) and in those with multiple treatment failures. A clear benefit of STI in patients with chronic infection remains controversial and these benefits are more often observed in patients starting treatment during primary HIV infection.