Effect of long-term trimethoprim/sulfamethoxazole treatment on resistance and integron prevalence in the intestinal flora: a randomized, double-blind, placebo-controlled trial in children

Exploring Gut Microbiota Alterations with Trimethoprim-Sulfamethoxazole and Dexamethasone in a Humanized Microbiome Mouse Model

Along with the standard therapies for glioblastoma, patients are commonly prescribed trimethoprim-sulfamethoxazole (TMP-SMX) and dexamethasone for preventing infections and reducing cerebral edema, respectively. Because the gut microbiota impacts the efficacy of cancer therapies, it is important to understand how these medications impact the gut microbiota of patients. Using mice that have been colonized with human microbiota, this study sought to examine how TMP-SMX and dexamethasone affect the gut microbiome. Two lines of humanized microbiota (HuM) Rag1-/- mice, HuM1Rag and HuM2Rag, were treated with either TMP-SMX or dexamethasone via oral gavage once a day for a week. Fecal samples were collected pre-treatment (pre-txt), one week after treatment initiation (1 wk post txt), and three weeks post-treatment (3 wk post txt), and bacterial DNA was analyzed using 16S rRNA-sequencing. The HuM1Rag mice treated with TMP-SMX had significant shifts in alpha diversity, beta diversity, and functional pathways at all time points, whereas in the HuM2Rag mice, it resulted in minimal changes in the microbiome. Likewise, dexamethasone treatment resulted in significant changes in the microbiome of the HuM1Rag mice, whereas the microbiome of the HuM2Rag mice was mostly unaffected. The results of our study show that routine medications used during glioblastoma treatment can perturb gut microbiota, with some microbiome compositions being more sensitive than others, and these treatments could potentially affect the overall efficacy of standard-of-care therapy.

Topical versus systemic antibiotics for chronic suppurative otitis media

BACKGROUND

Chronic suppurative otitis media (CSOM), sometimes referred to as chronic otitis media (COM), is a chronic inflammation and often polymicrobial infection (involving more than one micro-organism) of the middle ear and mastoid cavity, characterised by ear discharge (otorrhoea) through a perforated tympanic membrane. The predominant symptoms of CSOM are ear discharge and hearing loss. Antibiotics are the most common treatment for CSOM, which act to kill or inhibit the growth of micro-organisms that may be responsible for the infection. Antibiotics can be administered both topically and systemically, and can be used alone or in addition to other treatments for CSOM such as ear cleaning (aural toileting).

OBJECTIVES

To assess the effects of topical versus systemic antibiotics for people with CSOM.

SEARCH METHODS

The Cochrane ENT Information Specialist searched the Cochrane ENT Register; Central Register of Controlled Trials (CENTRAL via the Cochrane Register of Studies); Ovid MEDLINE; Ovid Embase; CINAHL; Web of Science; ClinicalTrials.gov; ICTRP and additional sources for published and unpublished trials. The date of the search was 16 March 2020.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) with at least a one-week follow-up involving patients (adults and children) who had chronic ear discharge of unknown cause or CSOM, where the ear discharge had continued for more than two weeks. The studies compared topical antibiotics against systemic (oral, injection) antibiotics. We separated studies according to whether they compared the same type of antibiotic in both treatment groups, or different types of antibiotics. For each comparison we considered whether there was background treatment for both treatment groups, for example aural toileting (ear cleaning).

DATA COLLECTION AND ANALYSIS

We used the standard Cochrane methodological procedures. We used GRADE to assess the certainty of the evidence for each outcome. Our primary outcomes were: resolution of ear discharge or 'dry ear' (whether otoscopically confirmed or not, measured at between one week and up to two weeks, two weeks up to four weeks, and after four weeks), health-related quality of life using a validated instrument, ear pain (otalgia) or discomfort or local irritation. Secondary outcomes included hearing, serious complications and ototoxicity measured in several ways.

MAIN RESULTS

Six studies (445 participants), all with high risk of bias, were included. All but two studies included patients with confirmed CSOM, where perforation of the ear drum was clearly documented. None of the studies reported results for resolution of ear discharge after four weeks or health-related quality of life. 1. Topical versus systemic administration of the same type of antibiotics (quinolones) Four studies (325 participants) compared topical versus systemic (oral) administration of ciprofloxacin. Three studies reported resolution of ear discharge at one to two weeks and found that the topical administration may slightly increase resolution (risk ratio (RR) 1.48, 95% confidence interval (CI) 1.24 to 1.76; 285 participants; 3 studies; I2 = 0%; low-certainty evidence). In these studies, aural toileting was either not mentioned, or limited to the first visit. Three studies (265 participants) reported that they did not suspect ototoxicity in any participants, but it is unclear how this was measured (very low-certainty evidence). No studies reported the outcomes of ear pain or serious complications. No studies reported results for hearing, despite it being measured in three studies. 2. Topical versus systemic administration of different types of antibiotics (quinolones versus aminoglycosides) One study (60 participants) compared topical ciprofloxacin versus gentamicin injected intramuscularly. No aural toileting was reported. Resolution of ear discharge was not measured at one to two weeks. The study did not report any 'side effects' from which we assumed that no ear pain, suspected ototoxicity or serious complications occurred (very low-certainty evidence). The study stated that "no worsening of the audiometric function related to local or parenteral therapy was observed". 3. Topical versus systemic administration of different types of antibiotics (quinolones versus amoxicillin-clavulanic acid) One study compared topical ofloxacin with amoxicillin-clavulanic acid with all participants receiving suction ear cleaning at the first visit. It is uncertain if there is a difference between the two groups in resolution of ear discharge at one to two weeks due to study limitations and the very small sample size (RR 2.93, 95% CI 1.50 to 5.72; 56 participants; very low-certainty evidence). It is unclear if there is a difference between topical quinolone compared with oral amoxicillin-clavulanic acid with regards to ear pain, hearing or suspected ototoxicity (very low-certainty evidence). No studies reported the outcome of serious complications.

AUTHORS' CONCLUSIONS

There was a limited amount of low-quality evidence available, from studies completed over 15 years ago, to examine whether topical or systemic antibiotics are more effective in achieving resolution of ear discharge for people with CSOM. However, amongst this uncertainty there is some evidence to suggest that the topical administration of antibiotics may be more effective than systemic administration of antibiotics in achieving resolution of ear discharge (dry ear). There is limited evidence available regarding different types of antibiotics. It is not possible to determine with any certainty whether or not topical quinolones are better or worse than systemic aminoglycosides. These two groups of compounds have different adverse effect profiles, but there is insufficient evidence from the included studies to make any comment about these. In general, adverse effects were poorly reported.

Systemic antibiotics for chronic suppurative otitis media

BACKGROUND

Chronic suppurative otitis media (CSOM) is a chronic inflammation and infection of the middle ear and mastoid cavity, characterised by ear discharge (otorrhoea) through a perforated tympanic membrane. The predominant symptoms of CSOM are ear discharge and hearing loss. Systemic antibiotics are a commonly used treatment option for CSOM, which act to kill or inhibit the growth of micro-organisms that may be responsible for the infection. Antibiotics can be used alone or in addition to other treatments for CSOM.

OBJECTIVES

To assess the effects of systemic antibiotics for people with CSOM.

SEARCH METHODS

The Cochrane ENT Information Specialist searched the Cochrane ENT Register; Central Register of Controlled Trials (CENTRAL via the Cochrane Register of Studies); Ovid MEDLINE; Ovid Embase; CINAHL; Web of Science; ClinicalTrials.gov; ICTRP and additional sources for published and unpublished trials. The date of the search was 16 March 2020.

SELECTION CRITERIA

We included randomised controlled trials comparing systemic antibiotics (oral, injection) against placebo/no treatment or other systemic antibiotics with at least a one-week follow-up period, involving patients with chronic (at least two weeks) ear discharge of unknown cause or due to CSOM. Other treatments were allowed if both treatment and control arms also received it.

DATA COLLECTION AND ANALYSIS

We used the standard Cochrane methodological procedures. We used GRADE to assess the certainty of the evidence for each outcome. Our primary outcomes were: resolution of ear discharge or 'dry ear' (whether otoscopically confirmed or not, measured at between one week and up to two weeks, two weeks to up to four weeks, and after four weeks); health-related quality of life using a validated instrument; ear pain (otalgia) or discomfort or local irritation. Secondary outcomes included hearing, serious complications and ototoxicity measured in several ways.

MAIN RESULTS

We included 18 studies (2135 participants) with unclear or high risk of bias. 1. Systemic antibiotics versus no treatment/placebo It is very uncertain if there is a difference between systemic (intravenous) antibiotics and placebo in the resolution of ear discharge at between one and two weeks (risk ratio (RR) 8.47, 95% confidence interval (CI) 1.88 to 38.21; 33 participants; 1 study; very low-certainty evidence). The study did not report results for resolution of ear discharge after two weeks. Health-related quality of life was not reported. The evidence is very uncertain for hearing and serious (intracranial) complications. Ear pain and suspected ototoxicity were not reported. 2. Systemic antibiotics versus no treatment/placebo (both study arms received topical antibiotics) Six studies were included of which five presented useable data. There may be little or no difference in the resolution of ear discharge at between one to two weeks for oral ciprofloxacin compared to placebo or no treatment when ciprofloxacin ear drops were used in both intervention arms (RR 1.02, 95% CI 0.93 to 1.12; 390 participants; low-certainty evidence). No results after two weeks were reported. Health-related quality of life was not reported. The evidence is very uncertain for ear pain, serious complications and suspected ototoxicity. 3. Systemic antibiotics versus no treatment/placebo (both study arms received other background treatments) Two studies used topical antibiotics plus steroids as background treatment in both arms. It is very uncertain if there is a difference in resolution of ear discharge between metronidazole and placebo at four weeks (RR 0.91, 95% CI 0.51 to 1.65; 40 participants; 1 study; very low-certainty evidence). This study did not report other outcomes. It is also very uncertain if resolution of ear discharge at six weeks was improved with co-trimoxazole compared to placebo (RR 1.54, 95% CI 1.09 to 2.16; 98 participants; 1 study; very low-certainty evidence). Resolution of ear discharge was not reported at other time points. From the narrative report there was no evidence of a difference between groups for health-related quality of life, hearing or serious complications (very low-certainty evidence). One study (136 participants) used topical antiseptics as background treatment in both arms and found similar resolution of ear discharge between the amoxicillin and no treatment groups at three to four months (RR 1.03, 95% CI 0.75 to 1.41; 136 participants; 1 study; very low-certainty evidence). The narrative report indicated no evidence of differences in hearing or suspected ototoxicity (both very low-certainty evidence). No other outcomes were reported. 4. Different types of systemic antibiotics This is a summary of four comparisons, where different antibiotics were compared to each other. Eight studies compared different types of systemic antibiotics against each other: quinolones against beta-lactams (four studies), lincosamides against nitroimidazoles (one study) and comparisons of different types of beta-lactams (three studies). It was not possible to conclude if there was one class or type of systemic antibiotic that was better in terms of resolution of ear discharge. The studies did not report adverse events well.

AUTHORS' CONCLUSIONS

There was a limited amount of evidence available to examine whether systemic antibiotics are effective in achieving resolution of ear discharge for people with CSOM. When used alone (with or without aural toileting), we are very uncertain if systemic antibiotics are more effective than placebo or no treatment. When added to an effective intervention such as topical antibiotics, there seems to be little or no difference in resolution of ear discharge (low-certainty evidence). Data were only available for certain classes of antibiotics and it is very uncertain whether one class of systemic antibiotic may be more effective than another. Adverse effects of systemic antibiotics were poorly reported in the studies included. As we found very sparse evidence for their efficacy, the possibility of adverse events may detract from their use for CSOM.

Daptomycin treatment impacts resistance in off-target populations of vancomycin-resistant Enterococcus faecium

The antimicrobial resistance crisis has persisted despite broad attempts at intervention. It has been proposed that an important driver of resistance is selection imposed on bacterial populations that are not the intended target of antimicrobial therapy. But to date, there has been limited quantitative measure of the mean and variance of resistance following antibiotic exposure. Here we focus on the important nosocomial pathogen Enterococcus faecium in a hospital system where resistance to daptomycin is evolving despite standard interventions. We hypothesized that the intravenous use of daptomycin generates off-target selection for resistance in transmissible gastrointestinal (carriage) populations of E. faecium. We performed a cohort study in which the daptomycin resistance of E. faecium isolated from rectal swabs from daptomycin-exposed patients was compared to a control group of patients exposed to linezolid, a drug with similar indications. In the daptomycin-exposed group, daptomycin resistance of E. faecium from the off-target population was on average 50% higher than resistance in the control group (n = 428 clones from 22 patients). There was also greater phenotypic diversity in daptomycin resistance within daptomycin-exposed patients. In patients where multiple samples over time were available, a wide variability in temporal dynamics were observed, from long-term maintenance of resistance to rapid return to sensitivity after daptomycin treatment stopped. Sequencing of isolates from a subset of patients supports the argument that selection occurs within patients. Our results demonstrate that off-target gastrointestinal populations rapidly respond to intravenous antibiotic exposure. Focusing on the off-target evolutionary dynamics may offer novel avenues to slow the spread of antibiotic resistance.

Distribution of class 1 integrons in historic and contemporary collections of human pathogenic Escherichia coli

Integrons play a major role in the evolution and spread of antimicrobial resistance in human pathogens, including Escherichia coli. This study describes the occurrence of class 1 integrons in human pathogenic E. coli, in three isolate collections involving three periods from the last 100 years (i) the Murray collection (n = 58 bacteria isolated from the 1910s to 1940s); (ii) the E. coli reference (ECOR) collection (n = 37 isolates mainly from the 1980s); and (iii) a recently assembled collection (n = 88 isolates obtained in 2016). High-quality whole genome sequences (WGSs) were available for all isolates. Integrons were detected in the WGSs with the program IntegronFinder and the results compared with three established methods: (i) polymerase chain reaction detection of the integrase gene; (ii) BLAST searching using draft genomes; and (iii) mapping of short reads. No integrons were found in any of the Murray Collection isolates; however, integrons were present in 3% of the isolates from ECOR collection, assembled in the 1980s, and 26% of the isolates from the 2010s. Similarly, antimicrobial resistance determinants were not present in the Murray Collection isolates, whereas they were present in 19% of the ECOR Collection isolates and in 55% of the isolates obtained in during the 2010s.

Topical antiseptics for chronic suppurative otitis media

BACKGROUND

Chronic suppurative otitis media (CSOM), sometimes referred to as chronic otitis media (COM), is a chronic inflammation and infection of the middle ear and mastoid cavity, characterised by ear discharge (otorrhoea) through a perforated tympanic membrane. The predominant symptoms of CSOM are ear discharge and hearing loss. Topical antiseptics, one of the possible treatments for CSOM, inhibit the micro-organisms that may be responsible for the infection. Antiseptics can be used alone or in addition to other treatments for CSOM, such as antibiotics or ear cleaning (aural toileting). Antiseptics or their application can cause irritation of the skin of the outer ear, manifesting as discomfort, pain or itching. Some antiseptics (such as alcohol) may have the potential to be toxic to the inner ear (ototoxicity), with a possible increased risk of causing sensorineural hearing loss, dizziness or tinnitus.

OBJECTIVES

To assess the effects of topical antiseptics for people with chronic suppurative otitis media.

SEARCH METHODS

The Cochrane ENT Information Specialist searched the Cochrane ENT Register; Central Register of Controlled Trials (CENTRAL; 2019, Issue 4, via the Cochrane Register of Studies); Ovid MEDLINE; Ovid Embase; CINAHL; Web of Science; ClinicalTrials.gov; ICTRP and additional sources for published and unpublished trials. The date of the search was 1 April 2019.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) with at least a one-week follow-up involving patients (adults and children) who had chronic ear discharge of unknown cause or CSOM, where the ear discharge had continued for more than two weeks. The interventions were any single, or combination of, topical antiseptic agent of any class, applied directly into the ear canal as ear drops, powders or irrigations, or as part of an aural toileting procedure. Two main comparisons were topical antiseptics compared to: a) placebo or no intervention; and b) another topical antiseptic (e.g. topical antiseptic A versus topical antiseptic B). Within each comparison we separated studies where both groups of patients had received topical antiseptics a) alone or with aural toileting and b) on top of antibiotic treatment.

DATA COLLECTION AND ANALYSIS

We used the standard Cochrane methodological procedures. We used GRADE to assess the certainty of the evidence for each outcome. Our primary outcomes were: resolution of ear discharge or 'dry ear' (whether otoscopically confirmed or not), measured at between one week and up to two weeks, two weeks to up to four weeks, and after four weeks; health-related quality of life using a validated instrument; ear pain (otalgia) or discomfort or local irritation. Secondary outcomes included hearing, serious complications and ototoxicity measured in several ways.

MAIN RESULTS

Five studies were included. It was not possible to calculate the total number of participants as two studies only provided the number of ears included in the study. A. Topical antiseptic (boric acid) versus placebo or no treatment (all patients had aural toileting) Three studies compared topical antiseptics with no treatment, with one study reporting results we could use (254 children; cluster-RCT). This compared the instillation of boric acid in alcohol drops versus no ear drops for one month (both arms used daily dry mopping). We made adjustments to the data to account for the intra-cluster correlation. The very low certainty of the evidence means it is uncertain whether or not treatment with an antiseptic leads to an increase in resolution of ear discharge at both four weeks (risk ratio (RR) 1.94, 95% confidence interval (CI) 1.20 to 3.16; 174 participants) and at three to four months (RR 1.73, 95% CI 1.21 to 2.47; 180 participants). This study narratively described no differences in suspected ototoxicity or hearing outcomes between the arms (very low-certainty evidence). None of the studies reported results for health-related quality of life, adverse effects or serious complications. B. Topical antiseptic A versus topical antiseptic B Two studies compared different antiseptics but only one (93 participants), comparing a single instillation of boric acid powder with daily acetic acid ear drops, provided any information for this comparison. The very low certainty of the evidence means that it is uncertain whether more patients had resolution of ear discharge with boric acid powder compared to acetic acid at four weeks (RR 2.61, 95% CI 1.51 to 4.53; 93 participants), or whether there was a difference between the arms with respect to ear discomfort due to the low number of reported events (RR 0.10, 95% CI 0.01 to 1.81; 93 participants). Narratively, the study reported no difference in hearing outcomes between the groups. None of the included studies reported any of the other primary or secondary outcomes.

AUTHORS' CONCLUSIONS

Due to paucity of the evidence and the very low certainty of that which is available the effectiveness and safety profile of antiseptics in the treatment of CSOM is uncertain.

Antibiotics versus topical antiseptics for chronic suppurative otitis media

BACKGROUND

Chronic suppurative otitis media (CSOM), sometimes referred to as chronic otitis media (COM), is a chronic inflammation and infection of the middle ear and mastoid cavity, characterised by ear discharge (otorrhoea) through a perforated tympanic membrane. The predominant symptoms of CSOM are ear discharge and hearing loss. Antibiotics and antiseptics kill or inhibit the micro-organisms that may be responsible for the infection. Antibiotics can be applied topically or administered systemically via the oral or injection route. Antiseptics are always directly applied to the ear (topically).

OBJECTIVES

To assess the effectiveness of antibiotics versus antiseptics for people with chronic suppurative otitis media (CSOM).

SEARCH METHODS

The Cochrane ENT Information Specialist searched the Cochrane ENT Register; Central Register of Controlled Trials (CENTRAL; 2019, Issue 4, via the Cochrane Register of Studies); Ovid MEDLINE; Ovid Embase; CINAHL; Web of Science; ClinicalTrials.gov; ICTRP and additional sources for published and unpublished trials. The date of the search was 1 April 2019.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) with at least a one-week follow-up involving patients (adults and children) who had chronic ear discharge of unknown cause or CSOM, where ear discharge had continued for more than two weeks. The intervention was any single, or combination of, antibiotic agent, whether applied topically (without steroids) or systemically. The comparison was any single, or combination of, topical antiseptic agent, applied as ear drops, powders or irrigations, or as part of an aural toileting procedure. Two comparisons were topical antiseptics compared to: a) topical antibiotics or b) systemic antibiotics. Within each comparison we separated where both groups of patients had received topical antibiotic a) alone or with aural toilet and b) on top of background treatment (such as systemic antibiotics).

DATA COLLECTION AND ANALYSIS

We used the standard Cochrane methodological procedures. We used GRADE to assess the certainty of the evidence for each outcome. Our primary outcomes were: resolution of ear discharge or 'dry ear' (whether otoscopically confirmed or not), measured at between one week and up to two weeks, two weeks to up to four weeks, and after four weeks; health-related quality of life using a validated instrument; and ear pain (otalgia) or discomfort or local irritation. Secondary outcomes included hearing, serious complications and ototoxicity measured in several ways.

MAIN RESULTS

We identified seven studies (935 participants) across four comparisons with antibiotics compared against acetic acid, aluminium acetate, boric acid and povidone-iodine. None of the included studies reported the outcomes of quality of life or serious complications. A. Topical antiseptic (acetic acid) versus topical antibiotics (quinolones or aminoglycosides) It is very uncertain if there is a difference in resolution of ear discharge with acetic acid compared with aminoglycosides at one to two weeks (risk ratio (RR) 0.88, 95% confidence interval (CI) 0.72 to 1.08; 1 study; 100 participants; very low-certainty evidence). No study reported results for ear discharge after four weeks. It was very uncertain if there was more ear pain, discomfort or local irritation with acetic acid or topical antibiotics due to the low numbers of participants reporting events (RR 0.16, 95% CI 0.02 to 1.34; 2 RCTs; 189 participants; very low-certainty evidence). No differences between groups were reported narratively for hearing (quinolones) or suspected ototoxicity (aminoglycosides) (very low-certainty evidence). B. Topical antiseptic (aluminium acetate) versus topical antibiotics No results for the one study comparing topical antibiotics with aluminium acetate could be used in the review. C. Topical antiseptic (boric acid) versus topical antibiotics (quinolones) One study reported more participants with resolution of ear discharge when using topical antibiotics (quinolones) compared with boric acid ear drops at between one to two weeks (risk ratio (RR) 1.56, 95% confidence interval (CI) 1.27 to 1.92; 1 study; 409 participants; moderate-certainty evidence). This means that one additional person will have resolution of ear discharge for every five people receiving topical antibiotics (compared with boric acid) at two weeks. No study reported results for ear discharge after four weeks. There was a bigger improvement in hearing in the topical antibiotic group compared to the topical antiseptic group (mean difference (MD) 2.79 decibels (dB), 95% CI 0.48 to 5.10; 1 study; 390 participants; low-certainty evidence) but this difference may not be clinically significant. There may be more ear pain, discomfort or irritation with boric acid compared with quinolones (RR 0.56, 95% CI 0.32 to 0.98; 2 studies; 510 participants; low-certainty evidence). Suspected ototoxicity was not reported. D. Topical antiseptic (povidone-iodine) versus topical antibiotics (quinolones) It is uncertain if there is a difference between quinolones and povidone-iodine with respect to resolution of ear discharge at one to two weeks (RR 1.02, 95% CI 0.82 to 1.26; 1 RCT, 39 participants; very low-certainty evidence). The study reported qualitatively that there were no differences between the groups for hearing and no patients developed ototoxic effects (very low-certainty evidence). No results for resolution of ear discharge beyond four weeks, or ear pain, discomfort or irritation, were reported. E. Topical antiseptic (acetic acid) + aural toileting versus topical + systemic antibiotics (quinolones) One study reported that participants receiving topical and oral antibiotics had less resolution of ear discharge compared with acetic acid ear drops and aural toileting (suction clearance every two days) at one month (RR 0.69, 95% CI 0.53 to 0.90; 100 participants). The study did not report results for resolution of ear discharge at between one to two weeks, ear pain, discomfort or irritation, hearing or suspected ototoxicity.

AUTHORS' CONCLUSIONS

Treatment of CSOM with topical antibiotics (quinolones) probably results in an increase in resolution of ear discharge compared with boric acid at up to two weeks. There was limited evidence for the efficacy of other topical antibiotics or topical antiseptics and so we are unable to draw conclusions. Adverse events were not well reported.

Topical antibiotics for chronic suppurative otitis media

BACKGROUND

Chronic suppurative otitis media (CSOM), sometimes referred to as chronic otitis media (COM), is a chronic inflammation and often polymicrobial infection (involving more than one micro-organism) of the middle ear and mastoid cavity, characterised by ear discharge (otorrhoea) through a perforated tympanic membrane. The predominant symptoms of CSOM are ear discharge and hearing loss. Topical antibiotics, the most common treatment for CSOM, act to kill or inhibit the growth of micro-organisms that may be responsible for the infection. Antibiotics can be used alone or in addition to other treatments for CSOM, such as antiseptics or ear cleaning (aural toileting).

OBJECTIVES

To assess the effects of topical antibiotics (without steroids) for people with CSOM.

SEARCH METHODS

The Cochrane ENT Information Specialist searched the Cochrane ENT Register; Central Register of Controlled Trials (CENTRAL via the Cochrane Register of Studies); Ovid MEDLINE; Ovid Embase; CINAHL; Web of Science; ClinicalTrials.gov; ICTRP and additional sources for published and unpublished trials. The date of the search was 1 April 2019.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) with at least a one-week follow-up involving participants (adults and children) who had chronic ear discharge of unknown cause or CSOM, where the ear discharge had continued for more than two weeks. The interventions were any single, or combination of, topical antibiotic agent(s) of any class, applied directly into the ear canal as ear drops, powders or irrigations, or as part of an aural toileting procedure. The two main comparisons were topical antibiotic compared to a) placebo or no intervention and b) another topical antibiotic (e.g. topical antibiotic A versus topical antibiotic B). Within each comparison we separated studies where both groups of participants had received topical antibiotic a) alone or with aural toileting and b) on top of background treatment (such as systemic antibiotics).

DATA COLLECTION AND ANALYSIS

We used the standard Cochrane methodological procedures. We used GRADE to assess the certainty of the evidence for each outcome. Our primary outcomes were: resolution of ear discharge or 'dry ear' (whether otoscopically confirmed or not), measured at between one week and up to two weeks, two weeks to up to four weeks and after four weeks; health-related quality of life using a validated instrument; ear pain (otalgia) or discomfort or local irritation. Secondary outcomes included hearing, serious complications and ototoxicity measured in several ways.

MAIN RESULTS

We included 17 studies with a total of 2198 participants. Twelve studies reported the sample size in terms of participants (not ears); these had a total of 1797 participants. The remaining five studies reported both the number of participants and ears, representing 401 participants, or 510 ears. A: Topical antibiotics versus placebo or no treatment (with aural toilet in both arms and no other background treatment) One small study compared a topical antibiotic (ciprofloxacin) with placebo (saline). All participants received aural toilet. Although ciprofloxacin was better than saline in terms of resolution of discharge at one to two weeks: 84% versus 12% (risk ratio (RR) 6.74, 95% confidence interval (CI) 1.82 to 24.99; 35 participants, very low-certainty evidence), the very low certainty of the evidence means that it is very uncertain whether or not one intervention is better or worse than the other. The study authors reported that "no medical side-effects and worsening of audiological measurements related to this topical medication were detected" (very low-certainty evidence). B: Topical antibiotics versus placebo or no treatment (with use of oral antibiotics in both arms) Four studies compared topical ciprofloxacin to no treatment (three studies; 190 participants) or topical ceftizoxime to no treatment (one study; 248 participants). In each study all participants received the same antibiotic systemically (oral ciprofloxacin, injected ceftizoxime). In at least one study all participants received aural toilet. Useable data were only available from the first three studies; ciprofloxacin was better than no treatment, resolution of discharge occurring in 88.2% versus 60% at one to two weeks (RR 1.47, 95% CI 1.20 to 1.80; 2 studies, 150 participants; low-certainty evidence). None of the studies reported ear pain or discomfort/local irritation. C: Comparisons of different topical antibiotics The certainty of evidence for all outcomes in these comparisons is very low. Quinolones versus aminoglycosides Seven studies compared an aminoglycoside (gentamicin, neomycin or tobramycin) with ciprofloxacin (734 participants) or ofloxacin (214 participants). Whilst resolution of discharge at one to two weeks was higher in the quinolones group the very low certainty of the evidence means that it is very uncertain whether or not one intervention is better or worse than the other (RR 1.95, 95% CI 0.88 to 4.29; 6 studies, 694 participants). One study measured ear pain and reported no difference between the groups. Quinolones versus aminoglycosides/polymyxin B combination ±gramicidin We identified three studies but data on our primary outcome were only available in one study. Comparing ciprofloxacin to a neomycin/polymyxin B/gramicidin combination, for an unknown treatment duration (likely four weeks), ciprofloxacin was better (RR 1.12, 95% CI 1.03 to 1.22, 186 participants). A "few" patients experienced local irritation upon the first instillation of topical treatment (numbers/groups not stated). Others Other studies examined topical gentamicin versus a trimethoprim/sulphacetamide/polymixin B combination (91 participants) and rifampicin versus chloramphenicol (160 participants). Limited data were available and the findings were very uncertain.

AUTHORS' CONCLUSIONS

We are uncertain about the effectiveness of topical antibiotics in improving resolution of ear discharge in patients with CSOM because of the limited amount of low-quality evidence available. However, amongst this uncertainty there is some evidence to suggest that the use of topical antibiotics may be effective when compared to placebo, or when used in addition to a systemic antibiotic. There is also uncertainty about the relative effectiveness of different types of antibiotics; it is not possible to determine with any certainty whether or not quinolones are better or worse than aminoglycosides. These two groups of compounds have different adverse effect profiles, but there is insufficient evidence from the included studies to make any comment about these. In general, adverse effects were poorly reported.

Bystander Selection for Antimicrobial Resistance: Implications for Patient Health

Antimicrobial therapy promotes resistance emergence in target infections and in off-target microbiota. Off-target resistance emergence threatens patient health when off-target populations are a source of future infections, as they are for many important drug-resistant pathogens. However, the health risks of antimicrobial exposure in off-target populations remain largely unquantified, making rational antibiotic stewardship challenging. Here, we discuss the contribution of bystander antimicrobial exposure to the resistance crisis, the implications for antimicrobial stewardship, and some novel opportunities to limit resistance evolution while treating target pathogens.

Integron Digestive Carriage in Human and Cattle: A "One Health" Cultivation-Independent Approach

Objectives: Dissemination of antimicrobial resistance (AMR) is a global issue that requires the adoption of a "One-Health" approach promoting integration of human and animal health. Besides culture-dependent techniques frequently used for AMR surveillance, cultivation-independent methods can give additional insights into the diversity and reservoir of AMR genetic determinants. Integrons are molecular markers that can provide overall and reliable estimation of AMR dissemination. In this study, considering the "One-Health" approach, we have analyzed the integron digestive carriage from stools of humans and cattle living in a same area and exposed to different antibiotic selection pressures. Methods: Three collections of human [general population (GP) and intensive care unit patients (ICUs)] and bovine (BOV) stool samples were analyzed. The three main classes of integrons were detected using a multiplex qPCR both from total DNA extracted from stools, and from Gram-negative bacteria obtained by culture after an enrichment step. Results: With the cultivation-independent approach, integron carriage was 43.8, 52.7, and 65.6% for GP, ICU, and BOV respectively, percentages being at least twofold higher to those obtained with the cultivation-dependent approach. Class 1 integrons were the most prevalent; class 2 integrons seemed more associated to cattle than to humans; no class 3 integron was detected. The integron carriage was not significantly different between GP and ICU populations according to the antibiotic consumption, whatever the approach. Conclusion: The cultivation-independent approach constitutes a complementary exploratory method to investigate the integron digestive carriage of humans and bovines, notably within subjects under antibiotic treatment. The high frequency of carriage of integrons in the gut is of clinical significance, integrons being able to easily acquire and exchange resistant genes under antibiotic selective pressure and so leading to the dissemination of resistant bacteria.

Marine Bivalve Mollusks As Possible Indicators of Multidrug-Resistant Escherichia coli and Other Species of the Enterobacteriaceae Family

The mechanisms for the development and spread of antibacterial resistance (ABR) in bacteria residing in environmental compartments, including the marine environment, are far from understood. The objective of this study was to examine the ABR rates in Escherichia coli and other Enterobacteriaceae isolates obtained from marine bivalve mollusks collected along the Norwegian coast during a period from October 2014 to November 2015. A total of 549 bivalve samples were examined by a five times three tube most probable number method for enumeration of E. coli in bivalves resulting in 199 isolates from the positive samples. These isolates were identified by biochemical reactions and matrix Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry, showing that 90% were E. coli, while the remaining were species within the genera Klebsiella, Citrobacter, and Enterobacter. All 199 isolates recovered were susceptibility tested following the European Committee on Antimicrobial Susceptibility Testing disk diffusion method. In total, 75 of 199 (38%) isolates showed resistance to at least one antibacterial agent, while multidrug-resistance were seen in 9 (5%) isolates. One isolate conferred resistance toward 15 antibacterial agents. Among the 75 resistant isolates, resistance toward extended-spectrum penicillins (83%), aminoglycosides (16%), trimethoprim (13%), sulfonamides (11%), tetracyclines (8%), third-generation cephalosporins (7%), amphenicols (5%), nitrofurans (5%), and quinolones (5%), were observed. Whole-genome sequencing on a selection of 10 E. coli isolates identified the genes responsible for resistance, including bla_CTX-M genes. To indicate the potential for horizontal gene transfer, conjugation experiments were performed on the same selected isolates. Conjugative transfer of resistance was observed for six of the 10 E. coli isolates. In order to compare E. coli isolates from bivalves with clinical strains, multiple-locus variable number tandem repeats analysis (MLVA) was applied on a selection of 30 resistant E. coli isolates. The MLVA-profiles were associated with community-acquired E. coli strains causing bacteremia. Our study indicates that bivalves represent an important tool for monitoring antibacterial resistant E. coli and other members of the Enterobacteriaceae family in the coastal environment.

Evaluation and management of recurrent urinary tract infections in children: state of the art

Urinary tract infections (UTIs) represent an important cause of febrile illness in young children and can lead to renal scarring and kidney failure. However, diagnosis and treatment of recurrent UTI in children is an area of some controversy. Guidelines from the American Academy of Pediatrics, National Institute for Health and Clinical Excellence and European Society of Paediatric Radiology differ from each other in terms of the diagnostic algorithm to be followed. Treatment of vesicoureteral reflux and antibiotic prophylaxis for prevention of recurrent UTI are also areas of considerable debate. In this review, we collate and appraise recently published literature in order to formulate evidence-based guidance for the diagnosis and treatment of recurrent UTI in children.

The influence of the accessory genome on bacterial pathogen evolution

Bacterial pathogens exhibit significant variation in their genomic content of virulence factors. This reflects the abundance of strategies pathogens evolved to infect host organisms by suppressing host immunity. Molecular arms-races have been a strong driving force for the evolution of pathogenicity, with pathogens often encoding overlapping or redundant functions, such as type III protein secretion effectors and hosts encoding ever more sophisticated immune systems. The pathogens' frequent exposure to other microbes, either in their host or in the environment, provides opportunities for the acquisition or interchange of mobile genetic elements. These DNA elements accessorize the core genome and can play major roles in shaping genome structure and altering the complement of virulence factors. Here, we review the different mobile genetic elements focusing on the more recent discoveries and highlighting their role in shaping bacterial pathogen evolution.

A new strategy to fight antimicrobial resistance: the revival of old antibiotics

The increasing prevalence of hospital and community-acquired infections caused by multidrug-resistant (MDR) bacterial pathogens is limiting the options for effective antibiotic therapy. Moreover, this alarming spread of antimicrobial resistance has not been paralleled by the development of novel antimicrobials. Resistance to the scarce new antibiotics is also emerging. In this context, the rational use of older antibiotics could represent an alternative to the treatment of MDR bacterial pathogens. It would help to optimize the armamentarium of antibiotics in the way to preserve new antibiotics and avoid the prescription of molecules known to favor the spread of resistance (i.e., quinolones). Furthermore, in a global economical perspective, this could represent a useful public health orientation knowing that several of these cheapest “forgotten” antibiotics are not available in many countries. We will review here the successful treatment of MDR bacterial infections with the use of old antibiotics and discuss their place in current practice.

Risk factors and outcomes of infections caused by extremely drug-resistant gram-negative bacilli in patients hospitalized in intensive care units

BACKGROUND

Extremely drug-resistant gram-negative bacilli (XDR-GNB) increasingly cause health care-associated infections (HAIs) in intensive care units (ICUs).

METHODS

A matched case-control (1:2) study was conducted from February 2007 to January 2010 in 16 ICUs. Case and control subjects had HAIs caused by GNB susceptible to ≤1 antibiotic versus ≥2 antibiotics, respectively. Logistic and Cox proportional hazards regression assessed risk factors for HAIs and predictors of mortality, respectively.

RESULTS

Overall, 103 case and 195 control subjects were enrolled. An immunocompromised state (odds ratio [OR], 1.55; P = .047) and exposure to amikacin (OR, 13.81; P < .001), levofloxacin (OR, 2.05; P = .005), or trimethoprim-sulfamethoxazole (OR, 3.42; P = .009) were factors associated with XDR-GNB HAIs. Multiple factors in both case and control subjects significantly predicted increased mortality at different time intervals after HAI diagnosis. At 7 days, liver disease (hazard ratio [HR], 5.52), immunocompromised state (HR, 3.41), and bloodstream infection (HR, 2.55) predicted mortality; at 15 days, age (HR, 1.02 per year increase), liver disease (HR, 3.34), and immunocompromised state (HR, 2.03) predicted mortality; and, at 30 days, age (HR, 1.02 per 1-year increase), liver disease (HR, 3.34), immunocompromised state (HR, 2.03), and hospitalization in a medical ICU (HR, 1.85) predicted mortality.

CONCLUSION

HAIs caused by XDR-GNB were associated with potentially modifiable factors. Age, liver disease, and immunocompromised state, but not XDR-GNB HAIs, were associated with mortality.

Panel 7: Treatment and comparative effectiveness research

BACKGROUND AND OBJECTIVES

Otitis media (OM) is one of the most common reasons for antibiotic treatment in children. Controversies regarding antibiotic treatment for OM have accumulated in the past decade, and there seem to be more dilemmas than certainties. The objectives of this article are to provide the state-of-the art review on achievements in treatment of all different stages of OM, including acute otitis media (AOM), otitis media with effusion (OME), and chronic suppurative otitis media, and to outline the future research areas.

DATA SOURCES

PubMed, Ovid Medline, the Cochrane Database, and Clinical Evidence (BMJ Publishing).

REVIEW METHODS

All types of articles related to OM treatment published in English between January 2007 and June 2011 were identified. A total of 286 articles related to OM treatment were reviewed by the panel members; 114 relevant quality articles were identified and summarized.

RESULTS

New evidence emerged on beneficial results of antibiotic treatment, compared with observation of AOM in young children who were diagnosed based on stringent criteria. In OME, the main results were related to a nonsignificant benefit of adenoidectomy versus tympanostomy tube placement alone in the treatment of chronic OME in younger children. Other modalities of OM treatment were studied and described herein.

CONCLUSIONS AND IMPLICATIONS FOR PRACTICE

Significant progress has been made in advancing the knowledge on the treatment of OM. Areas of potential future research have been identified and outlined.

The human microbiome as a reservoir of antimicrobial resistance

The gut microbiota is amongst the most densely populated microbial ecosystem on earth. While the microbiome exerts numerous health beneficial functions, the high density of micro-organisms within this ecosystem also facilitates horizontal transfer of antimicrobial resistance (AMR) genes to potential pathogenic bacteria. Over the past decades antibiotic susceptibility testing of specific indicator bacteria from the microbiome, such as Escherichia coli, has been the method of choice in most studies. These studies have greatly enlarged our understanding on the prevalence and distribution of AMR and associated risk factors. Recent studies using (functional) metagenomics, however, highlighted the unappreciated diversity of AMR genes in the human microbiome and identified genes that had not been described previously. Next to metagenomics, more targeted approaches such as polymerase chain reaction for detection and quantification of AMR genes within a population are promising, in particular for large-scale epidemiological screening. Here we present an overview of the indigenous microbiota as a reservoir of AMR genes, the current knowledge on this “resistome” and the recent and upcoming advances in the molecular diagnostic approaches to unravel this reservoir.

The co-selection of fluoroquinolone resistance genes in the gut flora of Vietnamese children

Antimicrobial consumption is one of the major contributing factors facilitating the development and maintenance of bacteria exhibiting antimicrobial resistance. Plasmid-mediated quinolone resistance (PMQR) genes, such as the qnr family, can be horizontally transferred and contribute to reduced susceptibility to fluoroquinolones. We performed an observational study, investigating the copy number of PMQR after antimicrobial therapy. We enrolled 300 children resident in Ho Chi Minh City receiving antimicrobial therapy for acute respiratory tract infections (ARIs). Rectal swabs were taken on enrollment and seven days subsequently, counts for Enterobacteriaceae were performed and qnrA, qnrB and qnrS were quantified by using real-time PCR on metagenomic stool DNA. On enrollment, we found no association between age, gender or location of the participants and the prevalence of qnrA, qnrB or qnrS. Yet, all three loci demonstrated a proportional increase in the number of samples testing positive between day 0 and day 7. Furthermore, qnrB demonstrated a significant increase in copy number between paired samples (p<0.001; Wilcoxon rank-sum), associated with non-fluoroquinolone combination antimicrobial therapy. To our knowledge, this is the first study describing an association between the use of non-fluoroquinolone antimicrobials and the increasing relative prevalence and quantity of qnr genes. Our work outlines a potential mechanism for the selection and maintenance of PMQR genes and predicts a strong effect of co-selection of these resistance determinants through the use of unrelated and potentially unnecessary antimicrobial regimes.

Has the emergence of community-associated methicillin-resistant Staphylococcus aureus increased trimethoprim-sulfamethoxazole use and resistance?: a 10-year time series analysis

There are an increasing number of indications for trimethoprim-sulfamethoxazole use, including skin and soft tissue infections due to community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA). Assessing the relationship between rates of use and antibiotic resistance is important for maintaining the expected efficacy of this drug for guideline-recommended conditions. Using interrupted time series analysis, we aimed to determine whether the 2005 emergence of CA-MRSA and recommendations of trimethoprim-sulfamethoxazole as the preferred therapy were associated with changes in trimethoprim-sulfamethoxazole use and susceptibility rates. The data from all VA Boston Health Care System facilities, including 118,863 inpatient admissions, 6,272,661 outpatient clinic visits, and 10,138 isolates were collected over a 10-year period. There was a significant (P = 0.02) increase in trimethoprim-sulfamethoxazole prescriptions in the post-CA-MRSA period (1,605/year) compared to the pre-CA-MRSA period (1,538/year). Although the overall susceptibility of Escherichia coli and Proteus spp. to trimethoprim-sulfamethoxazole decreased over the study period, the rate of change in the pre- versus the post-CA-MRSA period was not significantly different. The changes in susceptibility rates of S. aureus to trimethoprim-sulfamethoxazole and to methicillin were also not significantly different. The CA-MRSA period is associated with a significant increase in use of trimethoprim-sulfamethoxazole but not with significant changes in the rates of susceptibilities among clinical isolates. There is also no evidence for selection of organisms with increased resistance to other antimicrobials in relation to increased trimethoprim-sulfamethoxazole use.

Gibel carp Carassius auratus gut microbiota after oral administration of trimethoprim/ sulfamethoxazole

Trimethoprim/sulfamethoxazole is widely used in the treatment of infectious diseases caused by bacterial pathogens in aquaculture. However, the practice of antibiotic administration can promote the emergence of resistant strains of bacteria and result in a wane in efficacy over time. The objective of this study was to assess the effect of oral treatment with trimethoprim/sulfamethoxazole on the gastrointestinal (GI) microbiota of healthy gibel carp and those affected with bacterial enteritis. By using denaturing gradient gel electrophoresis (DGGE), the changes in the predominant bacterial communities were directly depicted for the first time. The main findings were (1) Actinobacteria, Firmicutes and Proteobacteria were the predominant phyla in the healthy gibel carp intestine; (2) administration of antibiotics had a more profound impact on the intestinal microflora of healthy fish than of the diseased ones; and (3) Enterobacteriaceae might be one of the major drug-resistant bacteria in the gibel carp intestine. This study provides an insight into the effect of antibiotic treatment on the establishment and colonization of fish GI microbiota and speculates on some possible drug-resistant bacteria.

Antibiotic therapy for inducible AmpC β-lactamase-producing Gram-negative bacilli: what are the alternatives to carbapenems, quinolones and aminoglycosides?

Some bacteria that possess chromosomally determined AmpC β-lactamases may express these enzymes at a high level following exposure to β-lactams, either by induction or selection for derepressed mutants. This may lead to clinical failure even if an isolate initially tests susceptible in vitro, a phenomenon best characterised by third-generation cephalosporin therapy for Enterobacter bacteraemia or meningitis. Several other Enterobacteriaceae, such as Serratia marcescens, Citrobacter freundii, Providencia spp. and Morganella morganii (often termed the 'ESCPM' group), may also express high levels of AmpC. However, the risk of clinical failure with β-lactams that test susceptible in vitro is less clear in these species than for Enterobacter. Laboratories frequently do not report β-lactam or β-lactamase inhibitor combination drug susceptibilities for ESCPM organisms, encouraging alternative therapy with quinolones, aminoglycosides or carbapenems. However, quinolones and carbapenems present problems with selective pressure for multiresistant organisms, and aminoglycosides with potential toxicity. The risk of emergent AmpC-mediated resistance for non-Enterobacter spp. appears rare in clinical studies. Piperacillin/tazobactam may remain effective and may be less selective for AmpC derepressed mutants than cephalosporins. The potential roles for agents such as cefepime or trimethoprim/sulfamethoxazole are also discussed. Clinical studies that better define optimal treatment for this group of bacteria are required.