Annual macrolide prescription rates and the emergence of macrolide resistance among Streptococcus pneumoniae in Canada from 1995 to 2005

The epidemiology of Helicobacter pylori resistance in a university affiliated hospital: a comparison between two time periods-a cross-sectional design

PURPOSE

During the last few decades, the increased use of various types of antibiotics in the general population caused a significant change in regional Helicobacter pylori (H. pylori) antibiotic resistance. Our aim is to study the changes in H. pylori resistance in patients who had undergone an esophagogastroduodenoscopy (EGD) and susceptibility testing and found positive for H. pylori. The study was conducted in a university affiliated hospital between 2013-2020.

METHODS

A cross-sectional study was performed on all consecutive patients who had undergone an EGD and tested positive for H. pylori at the Kaplan Medical Center, Israel. The study period was divided into two sub-periods: 2013-2016 and 2017-2020. Data on age, sex, comorbidities, previous treatments, and antimicrobial susceptibility testing for six antimicrobial agents were compared.

RESULTS

The resistance rates of H. pylori to clarithromycin and dual resistance to clarithromycin and metronidazole were found significantly higher during the late period. Multivariable analysis showed that the later period, older age, and diabetes mellitus were independent predictors for antimicrobial resistance.

CONCLUSIONS

Our study has shown that there is an increasing resistance of H. pylori to clarithromycin and metronidazole while its susceptibility is unaffected with time to other antibiotics. More recent cross-sectional studies with larger samples are warranted in order to evaluate the changes in the resistance patterns of H. pylori to various antibiotics with time.

Monitoring outpatient antibiotic utilization using reimbursement and retail sales data: a population-based comparison in France, 2012-17

OBJECTIVES

To assess whether a retail sales database could be used to monitor antibiotic utilization in the outpatient setting at the national level.

METHODS

We extracted 2012-17 outpatient antibiotic extrapolated retail sales (IQVIA's Xponent) and reimbursement data from the National Health Insurance (SNDS) in metropolitan France. We compared estimates of antibiotic use and consumption [number of antibiotic drug deliveries (DrID) and defined daily doses (DID) per 1000 inhabitants per day]. We relied on relative differences, Pearson's r statistics and time series using autoregressive integrated moving average (ARIMA) modelling to study: (i) differences in point estimates, (ii) correlation, and (iii) consistency in time trends between Xponent and SNDS. The analysis was conducted overall and in subgroups (age groups, therapeutic classes, major antimicrobial agents and regions).

RESULTS

We analysed approximately 377 million antibiotic drug deliveries, comprising nearly 3.4 billion DDDs. Overall, Xponent slightly overestimated SNDS point estimates with yearly relative differences of +3.5% for DrID and +3.3% for DID. Peaks in relative differences were observed for July and August months. Relative differences were <5% in most subgroups, except for fosfomycin and three French regions. Overall and across most subgroups, the correlation between Xponent and SNDS monthly aggregated estimates was almost perfect (r ≥ 0.992 for all subgroups, except for one region). ARIMA modelling showed high consistency between Xponent's and SDNS's DrID time series, but detected timepoints where the series significantly diverged.

CONCLUSIONS

IQVIA's Xponent and SNDS data were highly consistent. Xponent database seems suitable for monitoring outpatient antibiotic utilization in France.

Azithromycin Prescribing by Respiratory Pediatricians in Australia and New Zealand for Chronic Wet Cough: A Questionnaire-Based Survey

Aims: To determine how respiratory pediatricians across Australia and New Zealand prescribe azithromycin for children with chronic wet cough, including recurrent protracted bacterial bronchitis, chronic suppurative lung disease (CSLD) and bronchiectasis. Methods: A prospective web-based questionnaire was emailed to members of the Pediatric Special Interest Group of the Thoracic Society of Australia and New Zealand (TSANZ) between April and May 2018. It comprised eight demographic and 15 clinically focused questions. Results: Of the 73 respiratory pediatricians listed across Australia and New Zealand, 29 (40%) responded and all prescribed azithromycin for chronic wet cough. Twelve (41%) indicated that they would consider prescribing a short-course (2-4 weeks) of azithromycin for children with a chronic wet cough. Although most respondents reported prescribing long-term (>4-weeks) azithromycin for either CSLD (n = 23, 79%) or bronchiectasis (n = 24, 83%), only nine (31%) respondents would commence treatment if in the previous 12-months these children experienced three non-hospitalized exacerbations and just 12 (41%) would do so if there had been two hospitalisations for severe exacerbations during the same period in accordance with the TSANZ national guidelines. A lower threshold for prescribing azithromycin was described for Indigenous children or if co-morbidities were present. None prescribed azithromycin for >24-months. Macrolide-resistance was reported in Streptococcus pneumoniae and Staphylococcus aureus. Conclusion: Although Australian and New Zealand respiratory pediatricians in this survey prescribed azithromycin for chronic wet cough most often in children with either CSLD or bronchiectasis, many did so outside the current national guidelines. Reasons for this need exploring.

Risk of Hospitalization With Hemorrhage Among Older Adults Taking Clarithromycin vs Azithromycin and Direct Oral Anticoagulants

IMPORTANCE

Clarithromycin is a commonly prescribed antibiotic associated with higher levels of direct oral anticoagulants (DOACs) in the blood, with the potential to increase the risk of hemorrhage.

OBJECTIVE

To assess the 30-day risk of a hospital admission with hemorrhage after coprescription of clarithromycin compared with azithromycin among older adults taking a DOAC.

DESIGN, SETTING, AND PARTICIPANTS

This population-based, retrospective cohort study was conducted among adults of advanced age (mean [SD] age, 77.6 [7.2] years) who were newly coprescribed clarithromycin (n = 6592) vs azithromycin (n = 18 351) while taking a DOAC (dabigatran, apixaban, or rivaroxaban) in Ontario, Canada, from June 23, 2009, to December 31, 2016. Cox proportional hazards regression was used to examine the association between hemorrhage and antibiotic use (clarithromycin vs azithromycin). Statistical analysis was performed from December 23, 2019, to March 25, 2020.

MAIN OUTCOMES AND MEASURES

Hospital admission with major hemorrhage (upper or lower gastrointestinal tract or intracranial). Outcomes were assessed within 30 days of a coprescription.

RESULTS

Among the 24 943 patients (12 493 women; mean [SD] age, 77.6 [7.2] years) in the study, rivaroxaban was the most commonly prescribed DOAC (9972 patients [40.0%]), followed by apixaban (7953 [31.9%]) and dabigatran (7018 [28.1%]). Coprescribing clarithromycin vs azithromycin with a DOAC was associated with a higher risk of a hospital admission with major hemorrhage (51 of 6592 patients [0.77%] taking clarithromycin vs 79 of 18 351 patients [0.43%] taking azithromycin; adjusted hazard ratio, 1.71 [95% CI, 1.20-2.45]; absolute risk difference, 0.34%). Results were consistent in multiple additional analyses.

CONCLUSIONS AND RELEVANCE

This study suggests that, among adults of advanced age taking a DOAC, concurrent use of clarithromycin compared with azithromycin was associated with a small but statistically significantly greater 30-day risk of hospital admission with major hemorrhage.

Validating a popular outpatient antibiotic database to reliably identify high prescribing physicians for patients 65 years of age and older

Objective

Many jurisdictions lack comprehensive population-based antibiotic use data and rely on third party companies, most commonly IQVIA. Our objective was to validate the accuracy of the IQVIA Xponent antibiotic database in identifying high prescribing physicians compared to the reference standard of a highly accurate population-wide database of outpatient antimicrobial dispensing for patients ≥65 years.

Methods

We conducted this study between 1 March 2016 and 28 February 2017 in Ontario, Canada. We evaluated the agreement and correlation between the databases using kappa statistics and Bland-Altman plots. We also assessed performance characteristics for Xponent to accurately identify high prescribing physicians with sensitivity, specificity, positive predictive value (PPV), and negative predictive value.

Results

We included 9,272 physicians. The Xponent database has a specificity of 92.4% (95%CI 92.0%-92.8%) and PPV of 77.2% (95%CI 76.0%-78.4%) for correctly identifying the top 25^th percentile of physicians by antibiotic volume. In the sensitivity analysis, 94% of the top 25^th percentile physicians in Xponent were within the top 40^th percentile in the reference database. The mean number of antibiotic prescriptions per physician were similar with a relative difference of -0.4% and 2.7% for female and male patients, respectively. The error was greater in rural areas with a relative difference of -8.4% and -5.6% per physician for female and male patients, respectively. The weighted kappa for quartile agreement was 0.68 (95%CI 0.67–0.69).

Conclusion

We validated the IQVIA Xponent antibiotic database to identify high prescribing physicians for patients ≥65 years, and identified some important limitations. Collecting accurate population-based antibiotic use data will remain vital to global antimicrobial stewardship efforts.

High prevalence of multidrug-resistant international clones among macrolide-resistant Streptococcus pneumoniae isolates in immunocompromised patients in Tunisia

OBJECTIVES

Macrolide-resistant Streptococcus pneumoniae isolates have increased considerably in the last decade, with important geographical variations in involved phenotypes and genotypes. The aim of this study was to investigate phenotypes, genotypes, serotypes and genetic relatedness of macrolide-resistant S. pneumoniae isolated from immunocompromised patients in Tunisia.

METHODS

Antibiotic susceptibility was determined by disk diffusion, and MICs of erythromycin and clindamycin were determined for macrolide-resistant isolates by Etest. Macrolide-resistant isolates were analysed by PCR for ermB, mefA, tetM, tetO and Int-Tn1545. Serotyping was done by multiplex PCR and the Quellung reaction. Multilocus sequence typing (MLST) was performed for molecular typing.

RESULTS

Macrolide resistance was observed in 41 (69.5%) of 59 isolates. Of the 41 isolates, 37 (90.2%) had a macrolide-lincosamide-streptogramin B (MLS_B) resistance phenotype, with a predominance of high-level inducible MLS_B phenotype, and harboured the ermB gene. All isolates with high-level inducible MLS_B phenotype were highly resistant to erythromycin and clindamycin. Four isolates (9.8%) had a macrolide (M) resistance phenotype and harboured the mefA gene. Erythromycin-resistant isolates were multidrug-resistant (MDR) in 97.5% of cases and extensively drug-resistant in 12.2%. The isolates belonged essentially to four serotypes (19F, 23F, 14 and 6B). They were mainly assigned to three sequence types (ST81, ST2918 and ST386). Also, 65.9% of the isolates were grouped in three clonal complexes (CC81, CC838 and CC386).

CONCLUSIONS

These data indicate a high prevalence of Tn1545 transposon and of three MDR international clones contributing to the high frequency of multidrug resistance among S. pneumoniae isolates in our centre.

Short-course antimicrobial therapy for paediatric respiratory infections (SAFER): study protocol for a randomized controlled trial

Background

Community-acquired pneumonia (CAP) is commonly diagnosed in children. The Infectious Disease Society of America guidelines recommend 10 days of high-dose amoxicillin for the treatment of non-severe CAP but 5-day “short course” therapy may be just as effective. Randomized trials in adults have already demonstrated non-inferiority of 5-day short-course treatment for adults hospitalized with severe CAP and for adults with mild CAP treated as outpatients. Minimizing exposure to antimicrobials is desirable to avoid harms including diarrhoea, rashes, severe allergic reactions, increased circulating antimicrobial resistance, and microbiome disruption.

Methods

The objective of this multicentre, randomized, non-inferiority, controlled trial is to investigate whether 5 days of high-dose amoxicillin is associated with lower rates of clinical cure 14–21 days later as compared to 10 days of high-dose amoxicillin, the reference standard. Recruitment and enrolment will occur in the emergency departments of McMaster Children’s Hospital and the Children’s Hospital of Eastern Ontario. All children in the study will receive 5 days of amoxicillin after which point they will receive either 5 days of a different formulation of amoxicillin or a placebo. Assuming a clinical failure rate of 5% in the reference arm, a non-inferiority margin of 7.5%, one-sided alpha set at 0.025 and power of 0.80, 270 participants will be required. Participants from a previous feasibility study (n = 60) will be rolled over into the current study. We will be performing multiplex respiratory virus molecular testing, quantification of nasopharyngeal pneumococcal genomic loads, salivary inflammatory marker testing, and faecal microbiome profiling on participants.

Discussion

This is a pragmatic study seeking to provide high-quality evidence for front-line physicians evaluating children presenting with mild CAP in North American emergency departments in the post-13-valent pneumococcal, conjugate vaccine era. High-quality evidence supporting the non-inferiority of short-course therapy for non-severe paediatric CAP should be generated prior to making changes to established guidelines.

Trial registration

ClinicalTrials.gov, NCT02380352. Registered on 2 March 2015.

Electronic supplementary material

The online version of this article (10.1186/s13063-018-2457-2) contains supplementary material, which is available to authorized users.

Macrolides: a promising pharmacologic therapy for chronic obstructive pulmonary disease

Chronic inflammation plays a central role in the pathogenesis of chronic obstructive pulmonary disease (COPD). However, there are no effective anti-inflammatory pharmacologic therapies available for COPD so far. Recent evidence suggests that an immunologic mechanism has a role in the pathogenesis of COPD. Macrolides possess anti-inflammatory and immune-modulating effects may be helpful in the treatment of COPD. Several clinical studies have shown that long-term use of macrolides reduces the frequency of COPD exacerbations. However, the subgroups that most effectively respond to long-term treatment of macrolides still need to be determined. The potential adverse events to individuals and the microbial resistance in community populations raises great concern on the long-term use of macrolides. Thus, novel macrolides have anti-inflammatory and immuno-modulating effects, but without antibiotic effects, and are promising as an anti-inflammatory agent for the treatment of COPD. In addition, the combination of macrolides and other anti-inflammatory pharmacologic agents may be a new strategy for the treatment of COPD.

Antimicrobial stewardship: a Canadian perspective

Purpose

– The purpose of this paper is to explore the current state of antimicrobial stewardship implementation and development within Canada at both a federal and provincial level.

Design/methodology/approach

– Narrative review.

Findings

– There have been several prominent conferences and reports in Canada regarding the development and implementation of antimicrobial stewardship programs over the past two decades. However, despite the knowledge that there is a need for standardization of programs across Canada with accurate mechanisms and infrastructure in place for implementation and evaluation of these programs, there is still a lack of consistency across the country. In addition pharmacy information regarding inpatient and outpatient antimicrobial use is not uniformly reliable. Recently, the Public Health Agency of Canada using the Pan-Canadian Public Health Network as a vehicle organized a task group to help facilitate the working relationships among the provincial, territorial and federal governments in terms of implementing antimicrobial stewardship programs. This network has the potential to enhance and standardize programs across the country.

Originality/value

– This paper looks at Canadian policy regarding antimicrobial stewardship at a federal as well as provincial level. Historic conferences, reports and discussions are highlighted emphasizing the progressive changes over the past two decades and highlight many of the challenges that Canada continues to face.

Trends in secondary antibiotic resistance of Helicobacter pylori from 2007 to 2014: has the tide turned?

The current guidelines recommend culture and antibiotic susceptibility testing of Helicobacter pylori following two failed eradication attempts. Where testing is unavailable, epidemiological data for secondary H. pylori resistance are essential to allow for the rational use of antibiotics. The aim of this study was to describe the temporal changes in antibiotic resistance among adults previously treated for H. pylori infections and to identify predictors of resistance. Between 2007 and 2014, consecutive patients undergoing gastroscopy with H. pylori culture and susceptibility testing at our institution following at least two treatment failures were retrospectively identified. Antibiotic susceptibilities were recorded and linked to the demographic data. A total of 1,042 patients were identified, including 739 (70.9%) males, aged 39.3 ± 18.9 years. Resistance to clarithromycin, metronidazole, and levofloxacin was found in 57.2%, 64.4%, and 5.1% of isolates, respectively. Dual resistance to clarithromycin and metronidazole was seen in 39.9%. Over the study period, clarithromycin resistance increased annually in a linear manner (odds ratio [OR], 1.09; 95% confidence interval [CI], 1.03 to 1.14; P < 0.01), levofloxacin resistance decreased annually (OR, 0.78; 95% CI, 0.61 to 0.92; P < 0.01), and metronidazole resistance was nonlinear. Age was an independent predictor of resistance to all antibiotics. Time elapsed predicted resistance for clarithromycin and levofloxacin and dual resistance for clarithromycin-metronidazole. Secondary resistance of H. pylori to clarithromycin and metronidazole remains high. The low secondary resistance to levofloxacin makes it an attractive treatment option in our region for patients following two failed eradication attempts.

Effectiveness and safety of macrolides in bronchiectasis patients: a meta-analysis and systematic review

PURPOSE

Macrolides has been studied as a potential therapeutic anti-inflammatory agent for bronchiectasis patients, which has used as an immunoregulation agent. However, the efficacy and safety results of macrolides across available randomized controlled trials (RCTs) are controversial. The aim of this systematic review is to evaluate the efficacy and safety of macrolides in bronchiectasis.

METHODS

RCTs of macrolides treatment for the patients of bronchiectasis published in PubMed and Cochrane Library were searched. Two authors independently extracted data and assessment the methodological quality. The primary efficacy outcome was the impact on the number of pulmonary exacerbation. Safety outcomes included adverse events and mortality.

RESULTS

Seven RCTs were found in the systematic review and six studies were included in the present meta-analysis. Macrolides treatment showed a significant reduced rate of pulmonary exacerbation (RR = 0.55, 95%CI = 0.43-0.70) compared with control groups. However, subgroup analysis failed to find any significant changes in total 46 patients (RR = 0.20, 95%CI = 0.03-1.58) for treatment not more than 3 months. The incidence rates of total adverse events showed no significant difference among the macrolides group and control groups.

CONCLUSIONS

Long-term treatment of bronchiectasis with macrolides can reduce incidence of pulmonary exacerbation, especially in the subgroup treatment 6 months or more. There was no evidence of increased adverse events with macrolides. However, to verify the best macrolides regimen, more studies based on larger sample size and stratified by ethnicity are still needed.

CHEMICAL COMPOUNDS STUDIED IN THIS ARTICLE

Erythromycin (PubChem CID 12560); Azithromycin (PubChem CID: 447043); Clarithromycin (PubChem CID: 84029); Roxithromycin (PubChem CID: 5480431).

Risks of population antimicrobial resistance associated with chronic macrolide use for inflammatory airway diseases

Macrolide antibiotics have established efficacy in the management of cystic fibrosis and diffuse panbronchiolitis-uncommon lung diseases with substantial morbidity and the potential for rapid progression to death. Emerging evidence suggests benefits of maintenance macrolide treatment in more indolent respiratory diseases including chronic obstructive pulmonary disease and non-cystic fibrosis bronchiectasis. In view of the greater patient population affected by these disorders (and potential for macrolide use to spread to disorders such as chronic cough), widespread use of macrolides, particularly azithromycin, has the potential to substantially influence antimicrobial resistance rates of a range of respiratory microbes. In this Personal View, I explore theories around population (rather than patient) macrolide resistance, appraise evidence linking macrolide use with development of resistance, and highlight the risks posed by injudicious broadening of their use, particularly of azithromycin. These risks are weighed against the potential benefits of macrolides in less aggressive inflammatory airway disorders. A far-sighted approach to maintenance macrolide use in non-cystic fibrosis inflammatory airway diseases is needed, which minimises risks of adversely affecting community macrolide resistance: combining preferential use of erythromycin and restriction of macrolide use to those patients at greatest risk represents an appropriately cautious management approach.

Dominance of multidrug resistant CC271 clones in macrolide-resistant streptococcus pneumoniae in Arizona

BACKGROUND

Rates of resistance to macrolide antibiotics in Streptococcus pneumoniae are rising around the world due to the spread of mobile genetic elements harboring mef(E) and erm(B) genes and post-vaccine clonal expansion of strains that carry them.

RESULTS

Characterization of 592 clinical isolates collected in Arizona over a 10 year period shows 23.6% are macrolide resistant. The largest portion of the macrolide-resistant population, 52%, is dual mef(E)/erm(B)-positive. All dual-positive isolates are multidrug-resistant clonal lineages of Taiwan19F-14, mostly multilocus sequence type 320, carrying the recently described transposon Tn2010. The remainder of the macrolide resistant S. pneumoniae collection includes 31% mef(E)-positive, and 9% erm(B)-positive strains.

CONCLUSIONS

The dual-positive, multidrug-resistant S. pneumoniae clones have likely expanded by switching to non-vaccine serotypes after the heptavalent pneumococcal conjugate vaccine release, and their success limits therapy options. This upsurge could have a considerable clinical impact in Arizona.

Macrolides: from in vitro anti-inflammatory and immunomodulatory properties to clinical practice in respiratory diseases

BACKGROUND

Macrolides have long been recognised to exert immunomodulary and anti-inflammatory actions. They are able to suppress the "cytokine storm" of inflammation and to confer an additional clinical benefit through their immunomodulatory properties.

METHODS

A search of electronic journal articles was performed using combinations of the following keywords: macrolides, COPD, asthma, bronchitis, bronchiolitis obliterans, cystic fibrosis, immunomodulation, anti-inflammatory effect, diabetes, side effects and systemic diseases.

RESULTS

Macrolide effects are time- and dose-dependent, and the mechanisms underlying these effects remain incompletely understood. Both in vitro and in vivo studies have provided ample evidence of their immunomodulary and anti-inflammatory actions. Importantly, this class of antibiotics is efficacious with respect to controlling exacerbations of underlying respiratory problems, such as cystic fibrosis, asthma, bronchiectasis, panbrochiolitis and cryptogenic organising pneumonia. Macrolides have also been reported to reduce airway hyper-responsiveness and improve pulmonary function.

CONCLUSION

This review provides an overview on the properties of macrolides (erythromycin, clarithromycin, roxithromycin, azithromycin), their efficacy in various respiratory diseases and their adverse effects.

Evaluation of possible drug-drug interaction between gadoxetic acid and erythromycin as an inhibitor of organic anion transporting peptides (OATP)

PURPOSE

To evaluate if erythromycin compromises liver-specific enhancement of gadoxetic acid; both compounds competing in organic anion transporting peptides (OATP) -mediated hepatocytic uptake.

MATERIALS AND METHODS

The study was approved by institutional review board. Twelve healthy subjects (nine men, three woman; mean age, 38.7 years) were examined twice by MR imaging with prior administration of NaCl solution (placebo) or 1000 mg of erythromycin following a randomized sequence. Gadoxetic acid (0.025 mmol/kg body weight) was administered 15 min after the end of infusions. Pre- and 20 min postcontrast two-dimensional gradient-recalled-echo sequences were acquired. Relative enhancements of liver parenchyma and ratio of means were calculated from signal intensity measurements. Plasma levels of gadoxetic acid and erythromycin were determined and given in geometric means and coefficients of variation (CV).

RESULTS

Concentration of erythromycin directly after end of infusion was 13.9 mg/L (CV 14.9%). Gadolinium plasma concentrations 5 min after gadoxetic acid administration were 138.7 μmol/L (CV 20.4%) after erythromycin infusion and 129.6 μmol/L (CV 22.8%) after placebo. Mean relative enhancements of liver parenchyma were 88.1 (SD 24.9%) after erythromycin infusion and 92.6 (SD 17.9%) after placebo. Ratio of relative enhancements was 0.951 (95% confidence interval, 0.833; 1.061; statistically not significant).

CONCLUSION

Coadministration of erythromycin has no effect on gadoxetic acid enhanced liver MR imaging.

Resistance carrying plasmid in a traumatic wound

OBJECTIVE

To isolate and identify antibiotic-resistant bacteria from the exudate of a complex wound and determine if antibiotic resistance genes are chromosomal or plasmid borne.

METHOD

Antibiotic resistant bacteria from wound exudate of a single clinical sample were selected on agar media with ampicillin. A single colony was further screened for resistance to kanamycin by antibiotic-supplemented agar and to other antibiotics by an automated Phoenix instrument. Identification of the isolate was carried out by biochemical profiling and by 16S rDNA analysis.

RESULTS

Approximately 51% of total bacteria in the wound exudate with identical colony morphotype were resistant to 100 microg/ml of ampicillin. A single colony from this population also demonstrated resistance to 50 microg/ml of kanamycin on kanamycin-supplemented agar. Further antimicrobial sensitivity testing by the Phoenix instrument indicated resistance to inhibitory concentrations of amoxicillin-clavulanate, ampicillin-sulbactam, cefazolin, gentamicin, nitrofurantoin, tobramycin, and trimethoprim-sulfamethoxazole. Biochemical and 16S rDNA analysis identified this bacterial isolate as a member of genus Enterobacter. A plasmid preparation from this isolate successfully transferred ampicillin and kanamycin resistance to E. coli competent cells. E. coli transformants displayed two resistance phenotypes and the plasmids from these transformants displayed two different restriction type patterns, with one correlating to ampicillin and kanamycin resistance and the other only to ampicillin resistance.

CONCLUSION

A multiple antibiotic-resistant Enterobacter spp. from the wound fluid of a clinical sample was found to carry an antibiotic-resistant plasmid in a closely related species E. coli. The presence of antibiotic resistance plasmid in Enterobacteria that are part of the normal microbial flora of the human gut and skin could lead to the spread of resistance phenotype and emergence of antibiotic resistant pathogens. This study suggests normal human microbial fl ora could be a potential reservoir for resistance genes.

Pediatric complicated pneumonia and pneumococcal serotype replacement: trends in hospitalized children pre and post introduction of routine vaccination with Pneumococcal Conjugate Vaccine (PCV7)

Recent studies have described an increase in the incidence of complicated pneumonia in children, primarily caused by Streptococcus pneumoniae. The objective of this study was to determine if the incidence of complicated pneumonias in total and due to different pneumococcal serotypes has changed following the introduction of routine immunization with heptavalent pneumococcal conjugate vaccine (PCV7). A retrospective review of patients admitted to the Stollery Children's Hospital in Edmonton, Alberta with complicated pneumonia between July 1, 1997 and June 30, 2007 (5 years before and after the introduction of PCV7) was completed. There were 34 children in the pre- and 68 in the post-PCV7 era (14.31 and 19.91 per 10,000 discharges, respectively, p = 0.114). Patient characteristics were not significantly different, and pneumococcus was the most common organism isolated (pre: 21% (7/34); post: 26% (18/68), p = 0.515). In patients where serotype data was available, non-vaccine pneumococcal serotypes accounted for 67% (12/18) cases in the post-PVC7 era versus 14% (1/7) in the pre-PCV7 era (p = 0.031). The incidence of non-vaccine serotypes was 0.42 and 3.51 per 10,000 discharges in the pre- and post-PCV7 eras, respectively (p = 0.020). There has been a non-significant trend towards an increase in the incidence of complicated pneumonia following the introduction of PCV7. S. pneumoniae remains the predominant organism identified with non-vaccine serotypes now accounting for almost all cases. Although it is not clear if this increase is attributable to the use of PCV7, expanding pneumococcal serotype coverage has the potential to prevent complicated pneumonia.