Clinical isolates of Escherichia coli solely resistant to mecillinam: prevalence and epidemiology.

In routine susceptibility testing of Gram-negative bacteria, a particular resistance phenotype was observed: an Escherichia coli isolate from a urine sample exhibited resistance solely to mecillinam (MEC) but was fully susceptible to other ß-lactam antibiotics (MEC-R-BL-S). The objectives as this study were to determine the prevalence of this phenotype and to describe the phenotype, molecular epidemiology and genetic background. Between 1 January 2014 and 31 January 2016, MEC-R-BL-S E. coli isolates from urine were collected and genes previously reported as mostly involved in MEC resistance were analysed. The genetic relatedness among isolates was investigated by repetitive element sequence-based PCR (rep-PCR) and multilocus sequence typing (MLST). Ten MEC-R-BL-S isolates were collected, accounting for 0.4% (10/2547) of all E. coli obtained from urine samples, 0.9% (10/1135) of ampicillin-susceptible E. coli isolates and 9.6% (10/104) of MEC-R E. coli isolates. The isolates appeared as small colonies with round morphology and had impaired fitness. The isolates were not clonal and belonged to various extraintestinal or commensal E. coli phylogroups. Mutations in the cysB gene were evidenced in all clinical isolates. In conclusion, microbiologists should be aware of these isolates with a particular susceptibility phenotype, which is not due to error in disk diffusion but is a real non-enzymatic antibiotic resistance pattern.

Reduction of antibiotic use in the community reduces the rate of colonization with penicillin G-nonsusceptible Streptococcus pneumoniae.

BACKGROUND: There is a lack of evidence documenting the impact of optimized antibiotic use on the rates of colonization with penicillin G-nonsusceptible Streptococcus pneumoniae (PNSP) in children. This study evaluates the effect of community-based intervention strategies on the prevalence of pnsp colonization. METHODS: A controlled, population-based pharmacoepidemiological trial was conducted from January through May 2000. Three French geographic areas were selected on the basis of demographic similarities. Two intervention strategies were implemented: (1) reduced antibiotic use, which was achieved by not prescribing antibiotics for presumed viral respiratory tract infections (the prescription-reduction group); and (2) better adaptation of dose and duration (the dose/duration group). A control group received no intervention. The target population was children aged 3-6 years who were attending kindergarten. Oropharyngeal pneumococcus colonization and antibiotic use were monitored throughout the 5-month study. RESULTS: The prescription-reduction, dose/duration, and control groups included 601, 483, and 405 children, respectively. The interventions induced significantly larger decreases in antibiotic use in the prescription-reduction group (-18.8%) and dose/duration group (-17.1%) than in the control group (-3.8%), and the rates of PNSP colonization were initially similar for the 3 groups (52.5%, 55.1%, and 50.0%, respectively). At the end of the 5-month study, the rates of PNSP colonization were 34.5% for the prescription-reduction group (P=.05) and 44.3% for the dose/duration group (P=.8), compared with 46.2% for the control group. CONCLUSIONS: Intensive educational strategies aimed at optimizing antibiotic use can significantly reduce the rate of PNSP colonization in areas with high resistance rates.

Amoxicillin-clavulanate therapy increases childhood nasal colonization by methicillin-susceptible Staphylococcus aureus strains producing high levels of penicillinase.

We examined factors associated with penicillinase production by nasal carriage Staphylococcus aureus strains in 648 children aged 3 to 6 years attending 20 randomly sampled playschools. The children were prospectively monitored for drug use and medical events for 6 months and were then screened for S. aureus carriage. Isolates were tested for their susceptibility to penicillin G and methicillin, and penicillinase production by methicillin-susceptible, penicillin-resistant strains was quantified. S. aureus was isolated from 166 children (25.6%). Exposure to amoxicillin-clavulanate during the previous 3 months was associated with higher penicillinase production by penicillin-resistant, methicillin-susceptible strains (odds ratio, 3.6; P = 0.03). These results suggest that use of the amoxicillin-clavulanate combination could induce a herd selection process of S. aureus strains producing higher levels of penicillinase.

New highly selective inhibitors of class II fructose-1,6-bisphosphate aldolases.

Phosphoglycolo amidoxime and phosphoglycolo hydrazide, two new derivatives of phosphoglycolic acid, were synthesised and successfully tested as selective competitive inhibitors of class II FBP-aldolases.

Five day clarithromycin modified release versus 10 day penicillin V for group A streptococcal pharyngitis: a multi-centre, open-label, randomized study.

OBJECTIVE: A multicentre, comparative, randomized, open-label, Phase III trial evaluated the efficacy and tolerability of clarithromycin modified release (MR) versus penicillin V for pharyngitis due to group A beta-haemolytic streptococci (GABHS). METHODS: Three hundred and forty-nine patients (12-40 years) with acute pharyngotonsillitis and a positive Streptococcus A antigen immunoassay test were randomized to receive clarithromycin MR 500 mg od for 5 days or penicillin 590 mg tds for 10 days. Patients were clinically evaluated and a throat swab for culture obtained before treatment, after treatment (day 8 or 13 depending on the treatment arm) and at the follow-up visit (day 30). The main criterion for efficacy was the bacteriological cure rate after treatment. RESULTS: Three hundred and forty-nine patients were considered for the intent-to-treat analysis. After treatment, clinical cure rates were 88.1% in the clarithromycin group and 92.4% in the penicillin group, and eradication rates were 82.8% and 83.6%, respectively. There were no statistically significant differences between the two treatments. Three hundred and three (87%) patients had a positive culture before treatment, among which 29 (9.7%) were found to be clarithromycin resistant. Two hundred and thirty-nine patients were clinically and bacteriologically evaluable for per protocol analysis. After treatment, clinical cure rates were 95.2% in the clarithromycin group and 97.3% in the penicillin group, and eradication rates were 94.4% and 92%, respectively. No statistically significant difference was shown. Adverse events occurred in 46 patients of the clarithromycin group and 31 of the penicillin group (with no statistical difference). Most of them were of mild or moderate severity. CONCLUSION: Clarithromycin MR administered once daily for 5 days is as safe and effective as penicillin V administered three times a day for 10 days in the treatment of GABHS pharyngitis.

Efficacy of 5-day cefpodoxime proxetil for recurrent pharyngitis in adults. A comparative study with 10-day penicillin V or amoxycillin---clavulanate.

OBJECTIVE: To compare the clinical and bacteriologic efficacy of a 5-day course of cefpodoxime proxetil (CPD) with that of a 10-day course of penicillin V (PNV) or amoxycillin---clavulanate (AMC) in recurrent pharyngitis in adults. A cost-effectiveness study (reported elsewhere) was carried out at the same time. METHODS: This multicenter, randomized, open label trial involved 580 adult patients consulting general practitioners for clinical recurrent pharyngitis (greater-than-or-equal3 episodes within the last 12 months) regardless of the bacterial etiology. Patients were treated for 5 days with CPD, 100 mg twice daily, or for 10 days with PNV, 1x106 IU three times a day, or for 10 days with AMC, 500 mg (amoxycillin) three times a day. Clinical and bacteriologic outcomes were noted at the end of treatment, and cases of clinical recurrence were recorded during a 6-month follow-up period. RESULTS: At the end of treatment, clinical response was satisfactory in 157 of 170 (92.3%) patients on CPD, 147 of 166 (88.5%) patients on PNV, and 168 of 177 (94.9%) patients on AMC. Group A beta-hemolytic streptococci (GABHS) were eradicated in 22 of 23 (95.65%) patients on CPD, 16 of 16 (100%) patients on PNV, and 19 of 20 (95%) patients on AMC. The rates of clinical success and GABHS eradication were not significantly different between the groups. Compliance (p<0.001) and tolerance (p<0.001) were significantly better in the CPD group than in the other two groups. Among the 389 patients evaluable 6 months after the end of treatment, the recurrence rate of acute pharyngitis (due to any bacterium) was significantly lower in the CPD group (p=0.01 versus PNV; p<0.01 versus AMC). A Kaplan---Meier analysis (469 patients over 6 months) of the rate of non-recurrence, with comparison by the log-rank test, also showed a significant difference in favor of CPD. CONCLUSIONS: A 5-day treatment of recurrent pharyngitis with CPD was as effective and better tolerated than a 10-day treatment with PNV or AMC. The risk of recurrence was lower with CPD.