Use of colistin in adult patients: A cross-sectional study.

OBJECTIVES: The aim of this study was to assess colistin use in a country endemic for multidrug-resistant Gram-negative bacteria (MDR-GNB). METHODS: Colistin prescription patterns were evaluated in 22 Italian centres. Factors associated with use of colistin in combination with other anti-MDR-GNB agents were also assessed. RESULTS: A total of 221 adults receiving colistin were included in the study. Their median age was 64 years (interquartile range 52-73 years) and 134 (61%) were male. Colistin was mostly administered intravenously (203/221; 92%) and mainly for targeted therapy (168/221; 76%). The most frequent indications for colistin therapy were bloodstream infection and lower respiratory tract infection. Intravenous colistin was administered in combination with at least another anti-MDR-GNB agent in 80% of cases (163/203). A loading dose of 9 MU of colistimethate was administered in 79% of patients receiving i.v. colistin and adequate maintenance doses in 85%. In multivariable analysis, empirical therapy [odds ratio (OR) = 3.25, 95% confidence interval (CI) 1.24-8.53;P = 0.017] and targeted therapy for carbapenem-resistant Enterobacterales infection (OR = 4.76, 95% CI 1.69-13.43; P = 0.003) were associated with use of colistin in combination with other agents, whilst chronic renal failure (OR = 0.39, 95% CI 0.17-0.88; P = 0.024) was associated with use of colistin monotherapy. CONCLUSION: Colistin remains an important option for severe MDR-GNB infections when other treatments are not available. Despite inherent difficulties in optimising its use owing to peculiar pharmacokinetic/pharmacodynamic characteristics, colistin was mostly used appropriately in a country endemic for MDR-GNB.

Good tolerability of high dose colistin-based therapy in patients with haematological malignancies.

PURPOSE: Colistin is usually the only drug fully active against multi-drug resistant Gram-negative bacteria, but its nephrotoxicity might limit its use. Recent pharmacokinetic/pharmacodynamic data suggest that high dose of colistin, preceded by a loading dose, are needed to maximize its antibacterial effect. The aim of this study was to determine the safety of high doses colistin, in haematology population. METHODS: A retrospective review of haematology patients who received high dose colistin-based therapy in years 2011-2016 was performed. Nephrotoxicity was assessed using RIFLE criteria. RESULTS: Thirty patients who received 38 courses of colistin were included in the study. Colistin was always administered together with other antibiotics. Colistin was well tolerated, with one case of neurological toxicity and one of cutaneous reaction. There were 22 (58%) treatment cycles without any nephrotoxicity, even though during 16 of these cycles other nephrotoxic drugs were administered. Severe (injury or failure) renal toxicity occurred during 6 (16%) treatment courses, requiring colistin discontinuation in 2 patients and colistin dose reduction in 1. Poorer renal function at baseline and younger age were the only variables associated with increased renal toxicity (p = 0.011 and p = 0.031, respectively). Overall mortality was 18% (7/38) and 29% (11/38) at 7 and 30 days after the treatment onset. CONCLUSIONS: In adult haematology population, high dose colistin therapy is safe and efficacious, despite high frequency of concomitant nephrotoxic treatment.

Resistance to oral antibiotics in 4569 Gram-negative rods isolated from urinary tract infection in children.

UNLABELLED: To investigate antibiotic resistance among pathogens isolated from urines in a tertiary care children's hospital in Italy. Retrospective analysis of prospectively collected data on antibiotic susceptibility of Gram-negatives isolated from urines at the Istituto Giannina Gaslini, Genoa - Italy from 2007 to 2014. Antibiotic susceptibility was evaluated. By means of CLSI criteria from 2007 to 2010, while from 2011 EUCAST criteria were adopted. Data on susceptibility to amoxicillin-clavulanate, co-trimoxazole, cefuroxime, nitrofurantoin, fosfomycin and ciprofloxacin were evaluated for Escherichia coli, while for other Enterobacteriaceae data were collected for amoxicillin-clavulanate, co-trimoxazole and ciprofloxacin and for ciprofloxacin against Pseudomonas aeruginosa. Univariate and multivariable analyses were performed for risk factors associated with resistance. A total of 4596 Gram-negative strains were observed in 3364 patients. A significant increase in the proportion of resistant strains was observed for E.coli against amoxicillin-clavulanate, cefuroxime and ciprofloxacin and for others Enterobacteriaceae against co-trimoxazole and ciprofloxacin. Resistance to nitrofurantoin and fosfomycin was very infrequent in E.coli. Logistic regression analysis showed that repeated episode of urinary tract infections was a risk factor for E.coli resistance to amoxicillin-clavulanate, co-trimoxazole and cefuroxime, while admission in one of the Units usually managing children with urinary tract malformations was significantly associated to resistance to amoxicillin-clavulanate and cefuroxime. CONCLUSION: In conclusion the present study shows an increase in antibiotic resistance in pediatric bacteria isolated from urines in children, especially in presence of repeated episodes and/or urinary tract malformations. This resistance is worrisome for beta-lactams and cotrimoxazole, and start to increase also for fluoroquinolones while nitrofurantoin and fosfomycin still could represent useful drugs for oral treatment of these infections. WHAT IS KNOWN: • Infections are frequent in patients with urinary tract malformations • Antibiotic prophylaxis can select for resistant pathogens What is New: • The increase in the resistance to ß-lactams, co-trimoxazole or fluoroquinolones in pathogens causing urinary tract infections cause a reduction of drugs with oral formulations available for therapy • Old drugs like nitrofurantoin and fosfomycin can represent attractive compounds for oral treatment of urinary tract infections in children presence of resistance to other drug classes.

Trend of eGFR in an Italian cohort of mother-to-child HIV-infected patients exposed to tenofovir for at least 2 years.

UNLABELLED: The aim of this study is to describe longitudinal changes in estimated glomerular filtration rate (eGFR) in a cohort of mother-to-child HIV-infected adolescents exposed to tenofovir dixoproxil fumarate (TDF) for at least 2 years. We retrospectively examined eGFR at starting TDF (T0), at 24 months (T2) and at the final assessment (T3). Twenty-nine patients were studied. The mean duration of TDF exposure was 67 months (24-123). At baseline, the mean eGFR was 152 ml/min/1.73 m(2) (105-227, SD, 33). There was a significant decrease of eGFR from a mean of 152 ml/min/1.73 m(2) (SD, 33) at T0 to 140 ml/min/1.73 m(2) (SD, 33) at T2 and 123 ml/min/1.73 m(2) (SD, 14) at T3. The decrease of eGFR was significant, with ΔGFR (T3-T0) of -29 ml/min/1.73 m(2) (SD, 30; p < 0.0001) and a mean ΔGFR per year of -6 and ml/min/1.73 m(2) (SD, 8). CONCLUSION: We noted a long-term decline in eGFR in this small cohort of mother-to-child HIV-infected adolescents receiving TDF-containing cART, even if the lack of a control group and the small sample size are major limitations.

Phalangeal quantitative ultrasound: cheaper methods for screening and follow-up of bone pathologies in HIV-infected women?

This study estimated the prevalence of bone pathologies in a cohort of HIV-infected women in comparison with a cohort of HIV-negative women. Bone mineral density was measured by phalangeal quantitative ultrasound (AD-SoS: amplitude- dependent speed of sound; UBPI: ultrasound bone profile index). Risk of fracture, expressed by UBPI, was considered for value <0.39. Comparisons between groups and multivariate analyses were carried out using an ANOVA model. Correlations were evaluated using the Pearson correlation coefficient. Osteopenia and osteoporosis were present in 34.4% and 2% of patients, respectively. UBPI was pathologic in 5.7%. In a multivariate linear regression model significant correlations were found between AD-SoS z-score, duration of HIV-infection and BMI value. We also compared our cohort with 499 HIV-negative women as a historical control group of healthy subjects. AdSoS (2100 versus 2070 m/s) and UBPI (0.89 versus 0.74) were lower in HIV-infected women (p<0.001). Significant differences were also found in T-score values (p = 0.0013). These data show a high prevalence of bone diseases in women with HIV infection, correlated with duration of HIV-infection and BMI values. This non-invasive technique opens up new interesting perspectives, suggesting a possible use for bone mass screening in HIV-infected women.