UK researchers note worrisome antibiotic-resistant Shigella cluster
A UK study this week notes highly resistant Shigella sonnei isolates from men who have sex with men (MSM) who had engaged in high-risk activities, while Canadian scientists report a different antibiotic-resistant Shigella strain in a man with HIV, according to separate reports in Emerging Infectious Diseases.
In the first study, researchers from Public Health England report identifying a cluster of S sonnei in November 2015 that showed high levels of resistance to amoxicillin, ceftriaxone, tetracycline, sulphonamides, trimethoprim, and azithromycin and produced extended-spectrum beta-lactamase (ESBL). Those findings led the agency to sequence about 70% of S sonnei isolates obtained from hospital labs since August 2015.
Their investigation revealed nine patients whose fecal specimens tested positive for resistant S sonnei. Their gastrointestinal symptoms began from September to late December 2015. All seven patients who answered detailed questions about sexual history reported having male partners. Six reported sexual activities considered to be high risk for Shigella transmission, such as oral-anal contact and attendance at sex parties.
Isolates from all nine men produced ESBL and exhibited macrolide resistance. Whole-genome sequencing showed a close relationship among the isolates, which harbored a previously identified plasmid that has since acquired a mobile element, making it more easily transferred to another pathogen, the authors reported. No epidemiologic links were found among the patients, and no point sources were identified, making foodborne acquisition less likely.
In Canada, the researchers reported S flexneri in a 53-year-old HIV-positive MSM that was resistant to ampicillin, trimethoprim/sulfamethoxazole, nalidixic acid, ciprofloxacin, tetracycline, and chloramphenicol. It was susceptible to ceftriaxone, cefixime, ertapenem, and gentamicin and was also isolated last year.
Oct 3 Emerg Infect Dis UK report
Oct 3 Emerg Infect Dis Canadian case report
Study links nations' poverty to higher antimicrobial resistance levels
Researchers from India reported yesterday that countries with lower per-capita income have higher levels of antimicrobial resistance (AMR).
Writing in the International Journal of Infectious Diseases, a trio of scientists compared 2013-2014 gross national income per capita (GNIPC) with the prevalence of three common resistant bacteria: third-generation cephalosporin (3GC)-resistant Escherichia coli, methicillin-resistant Staphylococcus aureus (MRSA), and 3GC-resistant Klebsiella. Their analysis included 43 countries.
The researchers found that, for each log increase in GNIPC, levels of 3GC-resistant E coli, 3GC-resistant Klebsiella, and MRSA dropped 11.3%, 18.2%, and 12.3%, respectively. The association was stronger, however, for E coli and Klebsiella than for MRSA.
The authors concluded, "Our results underscore the urgent necessity of new policies aiming at reducing AMR in resource-poor settings."
Oct 4 Int J Infect Dis study