Our weekly wrap-up of antimicrobial stewardship & antimicrobial resistance scans
Researchers report high prevalence of MDR bacteria in Myanmar
Researchers in Myanmar are reporting high prevalence of multidrug-resistant (MDR) gram-negative bacteria among bloodstream isolates from patients at hospitals in the country's largest city.
In findings published in Emerging Infectious Diseases, the researchers report that, of the 592 blood cultures processed from patients at three hospitals in Yangon from July 2014 to December 2014, 42 (7.8%) yielded gram-negative bacteria. Of the 42 gram-negative isolates, 34 were Enterobacteriaceae (20 Escherichia coli, 7 Klebsiella pneumoniae, 6 Salmonella enterica, 1 Enterobacter cloacae) and 8 were non-fermenting gram-negative bacilli.
Almost 80% of the Enterobacteriaceae isolates were drug-resistant. Twenty (59%) were identified as MDR (with resistance to at least three classes of antimicrobial drugs), and 7 (21%) were classified as extensively drug resistant (with susceptibility to two or fewer classes of antimicrobial drugs), but all MDR Enterobacteriaceae were susceptible to polymixins.
Phenotypic testing suggested the presence of an extended-spectrum beta-lactamase (ESBL) enzyme in 16 of the gram-negative isolates and carbapenemase enzyme in 6 of the isolates. CTXM-15 ESBL and NDM carbapenemase were the most prevalent mechanisms of resistance.
"The high proportion of ESBL- and carbapenemase-producing gram-negative bacteria among bloodstream isolates from hospitalized patients in Yangon raises concern for the treatment of patients with gram-negative sepsis and suggests a need to reduce selective pressure and control the spread of resistant organisms," the authors write.
Mar 23 Emerg Infect Dis research letter
New initiative launched to address antimicrobial resistance challenges
The American Society of Microbiology (ASM) has launched a new initiative to analyze and share information on the current state of antimicrobial resistance and identify opportunities to address drug resistance challenges across the microbial sciences.
The ASM venture aims to address a host of antimicrobial resistance issues and identify approaches to maximize the impact on human, animal, and environmental health. Among the issues identified by the initiative's steering committee are the need for expanded surveillance into how resistance is spread, the need for antimicrobial stewardship across settings, the need for more research on environmental reservoirs of resistance, and the need for more research and funding for rapid diagnostic tests and new antibiotics.
ASM says the new initiative will complement existing efforts to address antimicrobial resistance and provide a mechanism for advancing research projects.
Mar 24 ASM press release
Review finds drug resistance is not just a problem with hospital infections
Originally published by CIDRAP News Mar 23
A new study in Clinical Infectious Diseases has found that antibiotic resistance has a significant clinical impact for patients with common infections managed in the community.
While much is known about the consequences of antibiotic-resistant infections in hospitalized patients, less is known about how antibiotic resistance affects clinical outcomes in common community-associated infections like urinary tract infections (UTIs) and respiratory infections. And because clinicians rarely report treatment failure from antibiotic resistance in these infections, there is a perception that antibiotic resistance doesn't have an effect on individual patients.
To get a better understanding of how antibiotic resistance can affect these conditions, the researchers set out to compare clinical outcomes between antibiotic-resistant and antibiotic-sensitive infections for patients with community-associated UTIs, respiratory tract infections, and skin and soft-tissue infections. To do that, they searched electronic databases for studies conducted in community settings that reported patient-level data on lab-confirmed infections, antibiotic resistance, and clinical outcomes.
The primary outcome of the study was clinical response failure. Secondary outcomes were re-consultation, further antibiotic prescriptions, symptom duration, and symptom severity.
The results of the 26 studies included in the review showed that, when compared with antibiotic-sensitive infections, clinical response failure was significantly more likely in patients who had antibiotic-resistant E coli UTIs (odds ratio [OR], 4.19), Streptococcus pneumoniae otitis media (OR, 2.51), and Streptococcus pneumoniae community-acquired pneumonia (OR, 2.15). In addition, patients with antibiotic-resistant E coli UTIs were found to be more likely to re-consult a healthcare professional and experience prolonged and more severe infections compared with patients who had antibiotic-sensitive infections.
"Antibiotic resistance has worse implications for patients' illness burden in the community," the authors write. "These findings could usefully inform better dialogue between clinician and patient, guidelines and campaigns about the benefits and risks of antibiotic treatment."
Mar 20 Clin Infect Dis abstract
Ocular specimens show little antimicrobial resistance
Originally published by CIDRAP News Mar 21
A new retrospective study from Mount Sinai Hospital showed low levels of antibiotic resistance and decreasing rates of methicillin-resistant Staphylococcus aureas (MRSA) rates in S aureus isolates taken from ocular samples.
This is one of the first studies to track antimicrobial resistance in the ophthalmology setting, where broad-spectrum antibiotics are often used to treat infections and prescribed before and after surgical procedures, the authors wrote in Antimicrobial Resistance and Infection Control. To conduct the study, the researchers tested ocular cultures collected between January of 2010 and December of 2015 at 25 inpatient and outpatient clinics within the Mount Sinai system.
A total of 540 bacterial organisms were gathered from 1,664 cultures, and 358 isolates underwent susceptibility testing. About 51% of isolates (182) were gram-positive, and S aureus was the most common gram-positive bacteria (62.1%). MRSA decreased during the study period, from 31% to 14% overall, but the drop was not consistent over the years nor statistically significant. Compared with methicillin-susceptible S aureus isolates, MRSA samples were much more resistant to fluoroquinolones, erythromycin, and trimethoprim/sulfamethoxazole (TMP/SMZ).
Streptococcus pneumoniae isolates showed reduced susceptibility to erythromycin. The most common gram-negative bacteria isolated were Haemophilus influenzae (26.1%) and Pseudomonas aeruginosa (23.9%); H influenzae isolates showed resistance to ampicillin and TMP/SMZ.
"Overall, antimicrobial resistance was infrequent for the Gram-negative and Gram-positive bacteria analyzed. While the MRSA isolates demonstrated increased resistance to multiple antimicrobial classes, this is expected for this pathogen," the authors concluded.
Mar 20 Antimicrob Resist Infect Control study
CDC reports 15 new drug-resistant Salmonella cases, ends investigation
Originally published by CIDRAP News Mar 20
The investigation into a multistate outbreak of multidrug-resistant (MDR) Salmonella Heidelberg infections tied to contact with dairy bull calves is now over after the pathogen sickened at least 36 people, hospitalizing 13, the Centers for Disease Control and Prevention (CDC) said today.
The update includes 15 new cases, including 5 hospitalizations, since the CDC first reported the outbreak on Nov 28, 2016. Illness-onset dates go back to Jan 27, 2015, with the latest being Jan 16 of this year. All but 8 of the patients, though, fell ill in June 2016 or later. Patients range in age from less than 1 year to 72 years, with a median of 18 years.
Ten states reported cases, with Wisconsin (15), Missouri (6), Minnesota (4), and South Dakota (4) having the most. No deaths were reported.
"This outbreak investigation is over," the CDC said. "However, infections in calves continue to be reported and people can still get a Salmonella infection from contact with livestock." The agency recommends washing hands thoroughly with soap and water immediately after contacting livestock or its surroundings, among other disease-prevention steps.
Among all 36 outbreak patients, 25 (69%) reported contact with dairy bull calves or other cattle before becoming sick. Some of the patients said they fell ill after their dairy bull calves became sick or died. The outbreak strain was identified in one patient's dairy calves.
All isolates tested from patients proved to be MDR. All five isolates tested were resistant to amoxicillin-clavulanic acid, ampicillin, cefoxitin, ceftriaxone, streptomycin, sulfisoxazole, and tetracycline and showed reduced susceptibility to ciprofloxacin. All, however, were susceptible to azithromycin, gentamicin, and meropenem. Four of the five isolates were also resistant to trimethoprim-sulfamethoxazole, and two of these were resistant to chloramphenicol and nalidixic acid.
Mar 20 CDC final update
Nov 28, 2016, CIDRAP News scan on original notice
Study: Following up on negative urine cultures aids antibiotic stewardship
Originally published by CIDRAP News Mar 20
Better follow-up of negative urine cultures substantially reduced the number of antibiotic days among pediatric urgent care patients, according to a new study in Pediatrics. The authors say the findings highlight empiric antibiotic treatment of urinary tract infection (UTI) in children as an important target for antibiotic stewardship.
For the study, researchers at Nationwide Children's Hospital (NCH)—an academic children's hospital in Columbus, Ohio, with a network of urgent care centers—set out to develop and implement a protocol for follow-up management on negative urine culture results. The purpose was to reduce inappropriate antibiotic exposure in patients with acute UTI at their urgent care centers. UTI is a common infection in children, but because physicians have to wait up to 48 hours for urine culture results, they frequently prescribe empiric antibiotic therapy based on symptoms. Prior to the study, NCH had no consistent mechanism in place to follow up on negative culture results and discontinue unnecessary antibiotic therapy.
The protocol standardized a process in which a nurse reviews the urine culture result and forwards a negative result to a physician, who then decides if antibiotic discontinuation is appropriate based on the results and clinical presentation. The nurse then notifies the patient or caregiver of the recommendation, and the physician documents the discontinuation of the antibiotics in the electronic medical record.
During the study period (July 2013 through December 2015), 910 patients received empiric antibiotic therapy for UTIs but had negative urine culture results. Among these patients, the rate of documented antibiotic discontinuation following a negative urine culture rose from a baseline mean of 4% to a mean of 84%, avoiding 3,429 (40%) of 8,648 antibiotic days prescribed. In addition, of the 46 patients who returned to an NCH urgent care center after antibiotic discontinuation, none were subsequently diagnosed as having a UTI.
"Our results highlight an essential opportunity in outpatient settings to introduce quality and stewardship measures for UTI management that will affect many patients and avoid a substantial number of antibiotic days," the authors write.
Mar 16 Pediatrics study
New AMR diagnostic tool outperforms competitors in analysis
Originally published by CIDRAP News Mar 20
A new diagnostic tool that identifies antimicrobial resistance (AMR) genes directly from paired sequencing reads outperformed other diagnostic tools in a new study in bioRxiv, a preprint server.
The tool, called ARIBA (Antimicrobial Resistance Identification by Assembly), uses a combined mapping/alignment and targeted local assembly approach to identify AMR genes and their variants efficiently and accurately from paired sequencing reads. This approach is considered less limited than other widely used diagnostic tools that either align sequencing reads to a set of reference genes or search for reference gene matches in de novo assembled sequences.
In head-to-head comparisons with the diagnostic tools SRST2 and KmerResistance, ARIBA was found to be just as accurate in identifying resistance genes in Enterococcus faecium and Shigella sonnei but was also able to identify and classify variants involved in AMR. In addition, it was able to report the presence of variants, and interpret their consequences, in Neisseria gonorrhea isolates. ARIBA was also faster and required fewer computational resources.
ARIBA was developed by researchers from the Wellcome Trust Sanger Institute.
Mar 18 bioRxiv abstract