Linear Regression Equations To Predict ß-Lactam, Macrolide, Lincosamide, and Fluoroquinolone MICs from Molecular Antimicrobial Resistance Determinants in Streptococcus pneumoniae.

Antimicrobial resistance in Streptococcus pneumoniae represents a threat to public health, and monitoring the dissemination of resistant strains is essential to guiding health policy. Multiple-variable linear regression modeling was used to determine the contributions of molecular antimicrobial resistance determinants to antimicrobial MICs for penicillin, ceftriaxone, erythromycin, clarithromycin, clindamycin, levofloxacin, and trimethoprim-sulfamethoxazole. Training data sets consisting of Canadian S. pneumoniae isolates obtained from 1995 to 2019 were used to generate multiple-variable linear regression equations for each antimicrobial. The regression equations were then applied to validation data sets of Canadian (n = 439) and U.S. (n = 607 and n = 747) isolates. The MICs for ß-lactam antimicrobials were fully explained by amino acid substitutions in motif regions of the penicillin binding proteins PBP1a, PPB2b, and PBP2x. Accuracies of predicted MICs within 1 doubling dilution to phenotypically determined MICs were 97.4% for penicillin, 98.2% for ceftriaxone, 94.8% for erythromycin, 96.6% for clarithromycin, 98.2% for clindamycin, 100% for levofloxacin, and 98.8% for trimethoprim-sulfamethoxazole, with an overall sensitivity of 95.8% and specificity of 98.0%. Accuracies of predicted MICs to the phenotypically determined MICs were similar to those of phenotype-only MIC comparison studies. The ability to acquire detailed antimicrobial resistance information directly from molecular determinants will facilitate the transition from routine phenotypic testing to whole-genome sequencing analysis and can fill the surveillance gap in an era of increased reliance on nucleic acid assay diagnostics to better monitor the dynamics of S. pneumoniae.

Response to pegylated interferon alfa-2a and ribavirin in chronic hepatitis C genotype 4.

The safety and efficacy of pegylated interferon (PEG-IFN) alfa-2a and ribavirin were studied among patients treated for genotype 4 chronic hepatitis C. Ninety-five patients with chronic hepatitis C genotype 4 were treated with PEG-IFN alfa-2a (180 microg/week) plus ribavirin (> or =11 mg/kg/day) for 48 weeks. The primary end point was sustained virological response, defined as non-detectable levels of HCV RNA at the end of follow up (week 72). The proportion with sustained virological response was 58/95 = 61.1% (95% CI = 50.5-70.9%). Side effects were generally mild, well managed by dose reductions (in 62% of patients); in only two patients were side effects sufficiently severe to require treatment interruption. Ninety percent of patients adhered to treatment up to week 12, and their sustained virological response rate was higher compared to non-adherent (65% vs. 22%, respectively, P = 0.012). None of the patients who failed to achieve 1 log reduction of viral load by week 8 (n = 15), or 2 log reduction by week 12 (n = 17), had a sustained virological response. In conclusion, sustained virological response in genotype 4 Egyptian patients treated with PEG-IFN alfa-2a and ribavirin was estimated around 60%, intermediate between sustained virological response observed in genotype 1 and genotype 2-3 patients in Western countries. The early virological response (week 4 or week 8) should be investigated as a criterion to decide whether the patient may benefit from a shorter duration of therapy.

Predictors of a sustained virological response in patients with genotype 4 chronic hepatitis C.

OBJECTIVES: To determine the clinical, biological, virological and histological predictive factors associated with a sustained virological response (SVR) to combined interferon therapy among Egyptian patients infected by genotype 4 hepatitis C virus (HCV). PATIENTS AND METHODS: Individual data from 250 patients with genotype 4 chronic hepatitis C, treated with different regimens of combined interferon, were analysed. The primary end point was SVR defined as undetectable HCV RNA by polymerase chain reaction (PCR) 24 weeks after the end of treatment. Multivariate logistic regression analysis was performed to select the independent prognostic parameters associated with SVR. RESULTS: A sustained virological response was achieved among 137/250 (54.8%) patients. Baseline factors independently and negatively associated with SVR were serum alpha-fetoprotein (AFP) level (above 0.3 upper limit of normal) [odds ratio (OR)=0.5, 95% confidence interval (CI): 0.2-0.8], severe fibrosis (Metavir score >F2) (OR=0.4, 95% CI: 0.2-0.8), presence of steatosis (OR=0.5, 95% CI: 0.3-0.97) and standard interferon treatment (OR=0.4, 95% CI: 0.2-0.8). CONCLUSIONS: Among genotype 4 chronic hepatitis C patients, severe fibrosis, severe steatosis, treatment with standard interferon and a high serum AFP level were all negatively associated with SVR. Pretreatment serum AFP level should be considered in the routine assessment of factors predictive of a treatment response.

Serum alpha-foetoprotein level predicts treatment outcome in chronic hepatitis C.

OBJECTIVES: To analyse the association between serum alpha-foetoprotein (AFP) levels and sustained virological response (SVR) in treated patients. METHODS: One-hundred patients with chronic hepatitis C were treated with pegylated interferon alpha-2a plus ribavirin for 48 weeks. The primary endpoint was SVR. Linear regression analysis was performed to identify clinical, biological, and histological factors affecting baseline AFP levels. The association between pretreatment serum AFP and SVR was assessed by multivariate logistic regression analysis. RESULTS: Of 100 patients, 95 were infected with genotype 4, one with genotype 1, and four with undetermined genotype. The median serum AFP level was 4.5 ng/ml and AFP values ranged from 1.2 to 49.8 ng/ml. In multivariate analysis, higher fibrosis stage and higher steatosis score were independently associated with higher serum AFP levels. SVR rate was 61.0% (61/100), and was lower for patients with AFP levels above rather than below the median value (40.8% versus 80.4%, respectively, P < 0.001). In multivariate analysis, including adjustment for age, gender, body mass index, steatosis score, fibrosis stage, ALT level, haemoglobin level, clotting time, HCV RNA viral load, and treatment dose received, a baseline serum AFP level above the median value was associated with a lower SVR rate (OR [95% CI]=0.10 [0.03-0.42], P < 0.001). None of the seven patients with increased (above 15 ng/ml) pretreatment AFP achieved SVR. CONCLUSIONS: In this study, higher baseline serum AFP levels independently predicted a lower SVR rate among patients with chronic hepatitis C. If confirmed with genotypes other than 4, these findings would suggest adding serum AFP to the list of factors predictive of treatment response.