Macrolide use identified as risk factor for macrolide-resistant Streptococcus pneumoniae in a 17-center case-control study

Invasive pneumococcal disease in Indian adults: 11 years' experience

PURPOSE

To investigate the epidemiology of invasive pneumococcal disease (IPD), prevalent serotypes, and pattern of antimicrobial resistance (AMR) in Indian adults.

METHODS

Prospective laboratory based surveillance of IPD was carried out in >18 years age group between January 2007 and July 2017, from a tertiary care hospital in South India. All Streptococcus pneumoniae culture positives from blood, CSF and sterile body fluids were characterized to identify the serotypes and AMR.

RESULTS

A total of 408 IPD cases were characterized in this study. The overall case fatality rate in this study was 17.8% (95% confidence interval (CI): 14.1, 22.4). Pneumonia (39%), meningitis (24.3%), and septicaemia (18.4%) were the most common clinical conditions associated with IPD. Serotypes 1, 3, 5, 19F, 8, 14, 23F, 4, 19A and 6B were the predominant serotypes in this study. Penicillin non-susceptibility was low with 6.4% CONCLUSION: Serotype data from this study helped in accurate estimation of pneumococcal conjugate vaccine-13 and pneumococcal polysaccharide vaccine-23 protective coverage against serotypes causing IPD in India as 58.7% (95% CI: 53.8, 63.4) and 67.4% (95% CI: 62.7, 71.8) respectively. Penicillin non-susceptibility in meningeal IPD cases is 27.4%. Empirical therapy for meningeal IPD must be cephalosporin in combination with vancomycin since cefotaxime non-susceptibility in meningeal IPD is 9.9.

Beta-lactam versus beta- lactam/macrolide therapy in pediatric outpatient pneumonia

OBJECTIVE

The objective was to evaluate the comparative effectiveness of beta-lactam monotherapy and beta- lactam/macrolide combination therapy in the outpatient management of children with community-acquired pneumonia (CAP).

METHODS

This retrospective cohort study included children, ages 1-18 years, with CAP diagnosed between January 1, 2008 and January 31, 2010 during outpatient management in the Geisinger Health System. The primary exposure was receipt of beta-lactam monotherapy or beta-lactam/macrolide combination therapy. The primary outcome was treatment failure, defined as a follow-up visit within 14 days of diagnosis resulting in a change in antibiotic therapy. Logistic regression within a propensity score- restricted cohort was used to estimate the likelihood of treatment failure.

RESULTS

Of 717 children in the analytical cohort, 570 (79.4%) received beta-lactam monotherapy and 147 (20.1%) received combination therapy. Of those who received combination therapy 58.2% of children were under 6 years of age. Treatment failure occurred in 55 (7.7%) children, including in 8.1% of monotherapy recipients, and 6.1% of combination therapy recipients. Treatment failure rates were highest in children 6-18 years receiving monotherapy (12.9%) and lowest in children 6-18 years receiving combination therapy (4.0%). Children 6-18 years of age who received combination therapy were less likely to fail treatment than those who received beta-lactam monotherapy (propensity-adjusted odds ratio, 0.51; 95% confidence interval, 0.28, 0.95).

CONCLUSION

Children 6-18 years of age who received beta- lactam/macrolide combination therapy for CAP in the outpatient setting had lower odds of treatment failure compared with those who received beta-lactam monotherapy.

Epidemiological interpretation of studies examining the effect of antibiotic usage on resistance

Bacterial resistance to antibiotics is a growing clinical problem and public health threat. Antibiotic use is a known risk factor for the emergence of antibiotic resistance, but demonstrating the causal link between antibiotic use and resistance is challenging. This review describes different study designs for assessing the association between antibiotic use and resistance and discusses strengths and limitations of each. Approaches to measuring antibiotic use and antibiotic resistance are presented. Important methodological issues such as confounding, establishing temporality, and control group selection are examined.

Antimicrobial agent exposure and the emergence and spread of resistant microorganisms: issues associated with study design

Antibiotics are essential agents that have greatly reduced human mortality due to infectious diseases. Their use, and sometimes overuse, have increased over the past several decades in humans, veterinary medicine and agriculture. However, the emergence of resistant pathogens is becoming an increasing problem that could result in the re-emergence of infectious diseases. Antibiotic prescription in human medicine plays a key role in this phenomenon. Under selection pressure, resistance can emerge in the commensal flora of treated individuals and disseminate to others. However, even if the effects of antimicrobial use on resistance is intuitively accepted, scientific rationales are required to convince physicians, legislators and public opinion to adopt appropriate behaviours and policies. With this review, we aim to provide an overview of different epidemiological study designs that are used to study the relationship between antibiotic use and the emergence and spread of resistance, as well as highlight their main strengths and weaknesses.

A challenge to appropriate antibiotic use in children with respiratory infections: a 5-year single-institution experience

BACKGROUND

We have studied the rate of emergence of antibiotic-resistant Streptococcus pneumoniae (S. pneumoniae) and Haemophilus influenzae (H. influenzae) and the subsequent antibiotic use in host patients of those isolates at the Department of Pediatrics, Soma General Hospital, Fukushima. Moreover, we carried out several studies investigating the risks and benefits of antibiotic-free treatment for children with respiratory infections. In this report, we summarize our research and suggest better treatment options for pediatric patients with respiratory infections.

METHODS

We investigated the necessity of antibiotic use in the treatment of pediatric inpatients with respiratory syncytial virus (RSV) infection, and tested our hypothesis that antibiotic-free treatment for common cold will reduce the number of resistant S. pneumoniae strains in the pediatric nasopharynx. Therefore, we restricted prescribing antibiotics for pediatric patients with respiratory infections. The rates of resistant S. pneumoniae and H. influenzae and the medication history of the host patients before and after the intervention were compared.

RESULTS

We found that most of the RSV-infected patients recovered without antibiotic treatment, and that the antibiotic-free treatment inhibited the emergence of antibiotic-resistant strains. The rate of penicillin-resistant S. pneumoniae decreased but the rate of ampicillin-resistant H. influenzae did not change significantly during the study.

CONCLUSION

We concluded that patients with respiratory infections can be treated without antibiotics, under careful examination and observation. Continued monitoring of such new interventions as well as recommending their use to other caregivers and physicians will help inhibit the spread of resistant strains.

Non-antibiotic treatment for pediatric outpatients with common cold inhibits the emergence of drug resistant pneumococci

The occurrence of drug resistant Streptococcus pneurmoniae (S. pneumoniae) is very high in Japan. Unnecessary use of antibiotics had been thought to cause this problem but previous studies had not clearly showed that the decreasing rate of antibiotic use had been related to the reduction of the prevalence of resistant strains. In this study, we tried to prove that non-antibiotic treatment for common cold would reduce the antibiotic resistant S. pneumoniae in nasopharynx in children. Forty-five children with the common cold were randomly selected from pediatric patients who had taken antibiotics within the past three months. We collected nasopharyngeal swabs from all of the participants and once again after a period of 2 to 3 months without using any antibiotics. Twenty-four of these patients had the S. pneumoniae strains isolated. Then these strains were undergone a susceptibility test and drug-resistant gene detection. The susceptibility test reveled that patients with penicillin-resistant strains decreased from 17 to 7 (p < 0.01). The test also reveled that the decreased number of patients had strains that were resistant to cefditren. The gene detection revealed that none of the patients acquired a higher resistance to penicillin. Our study suggests that the treatment without antibiotics reduces the drug-resistant S. pneumoniae. Controlled antibiotic use in children might prevent children from carrying the antibiotic resistant S. pneumoniae.

Comparative in vitro and bactericidal activities of telithromycin against penicillin-nonsusceptible, levofloxacin-resistant, and macrolide-resistant Streptococcus pneumoniae by time-kill methodology

Broth microdilution MICs were determined for 14 antimicrobial agents against 296 clinical, non-duplicate isolates of Streptococcus pneumoniae collected at Methodist Hospital (Indianapolis, Indiana, USA) from January 2001 to December 2003. Isolates were categorized as susceptible, intermediate, or resistant using Clinical and Laboratory Standards Institute breakpoints. Time-kill studies were performed to evaluate the bactericidal activity of telithromycin at 1, 2, 4, and 8x MIC against 10 penicillin-nonsusceptible, levofloxacin-resistant, and macrolide-resistant (7 M-phenotype, 3 MLS(B)-phenotype) strains. Bactericidal activity was defined as a >/=3-log(10) reduction in CFU/mL. The prevalence of resistance was highest for the macrolides (32%), followed by penicillin (16.2%), clindamycin (10.8%), amoxicillin+/-clavulanate (4.4%), levofloxacin (3.0%), gatifloxacin and moxifloxacin (2.4%), ceftriaxone and cefotaxime (2.0%), and gemifloxacin (1.4%). None of the isolates tested were resistant to telithromycin. At 24h, telithromycin was bactericidal for 0/10, 2/10, 7/10, and 7/10 isolates at 1x MIC, 2x MIC, 4x MIC, and 8x MIC, respectively. At 4-8x MIC, telithromycin was bactericidal for 7/7 M-phenotype isolates and 0/3 MLS(B)-phenotype isolates. For the MLS(B)-phenotype isolates, colony counts were decreased by 1.3-2.1log(10) colony-forming units/mL after 24h at 8x MIC. Overall, telithromycin was highly active against 296 isolates of S. pneumoniae from our institution and demonstrated bactericidal activity at clinically achievable concentrations for 7 of 10 penicillin-nonsusceptible, levofloxacin-resistant, and macrolide-resistant S. pneumoniae. However, telithromycin was bacteriostatic for the MLS(B)-phenotype isolates.

Optimizing the management of community-acquired respiratory tract infections in the age of antimicrobial resistance

Community-acquired respiratory tract infections (CARTIs) are the most common reason for prescribing antibiotics in the primary care setting. However, over the last decade, the management of CARTIs has become increasingly complicated by the steady increase in prevalence of drug-resistant pathogens responsible for these infections. As a result, significant attention has been directed at understanding the mechanisms of pathogen acquisition of resistance, drivers of resistance and methods for preventing the development of resistance. Data from recent surveillance studies suggest a slowing or decline in resistance rates to agents, such as beta-lactams, macrolides, tetracyclines and folic acid metabolism inhibitors. However, resistance to one antimicrobial family--the fluoroquinolones--while still low, appears to be on the increase. This is of significant concern given the rapid increase in resistance noted with older antibiotics in recent history. While the clinical implications of antibacterial resistance are poorly understood, the overall rates of antimicrobial resistance, as reported in recent surveillance studies, do not correspond to current rates of failure in patients with CARTIs. This disconnection between laboratory-determined resistance and clinical outcome has been termed the in vitro-in vivo paradox and several explanations have been offered to explain this phenomenon. Solving the problem of antimicrobial resistance will be multifactorial. Important factors in this effort include the education of healthcare providers, patients and the general healthcare community regarding the hazards of inappropriate antibiotic use, prevention of infections through vaccination, development of accurate, inexpensive and timely point-of-care diagnostic tests to aid in patient assessment, institution of objective treatment guidelines and use of more potent agents, especially those with a focused spectrum of activity, earlier in the treatment of CARTIs as opposed to reserving them as second-line treatment options. Ultimately, the single-most important factor will be the judicious use of antibiotics, as fewer antibiotic prescriptions lead to fewer antimicrobial-resistant bacteria.

Macrolide and ketolide resistance with Streptococcus pneumoniae

Antimicrobial agents in the macrolide family have long been considered drugs of potential utility in the management of infections caused by Streptococcus pneumoniae. However, with the emergence of macrolide resistance, the clinical value of macrolides in pneumococcal infections is threatened. In part, as a consequence of the development of macrolide resistance, recently the first agent in the ketolide antimicrobial class, telithromycin, was developed and introduced into clinical practice. The ketolides are macrolide antimicrobials whose chemistry has been modified so as avoid the effects of the most common mechanisms of macrolide resistance with S pneumoniae. This discussion reviews the current state of resistance to macrolides and ketolides with S pneumoniae in North America.