Rise of multidrug-resistant non-vaccine serotype 15A Streptococcus pneumoniae in the United Kingdom, 2001 to 2014

Abstract

Conjugate vaccines have reduced pneumococcal disease in vaccinated children and unvaccinated adults, but non-vaccine serotypes are of concern, particularly if antibiotic resistant. We reviewed Streptococcus pneumoniae collected via: (i) the British Society for Antimicrobial Chemotherapy (BSAC) surveillances from 2001–2014; (ii) Public Health England’s (PHE) invasive isolate surveillance from 2005–2014 and (iii) referral to PHE for resistance investigation from 2005–2014. Serotype 15A increased in all series, with many representatives showing triple resistance to macrolides, tetracyclines and penicillin. 15A was consistently among the 10 most prevalent serotypes from 2011 in PHE and BSAC invasive isolate/bacteraemia surveillance but never previously; 26–33% of these invasive 15A isolates had triple resistance. BSAC respiratory isolates were only serotyped in 2013/14 and 2014/15 (October to September); 15A was most prevalent serotype in both periods, comprising 9–11% of isolates, 38–48% of them with triple resistance. Serotype 15A represented 0–4% of S. pneumoniae referred to PHE for reference investigation annually until 2008 but rose to 29% (2013) and 32% (2014). Almost all multidrug-resistant 15A isolates were sequence type (ST) 63 variants, whereas susceptible 15A isolates were clonally diverse. The rise of serotype 15A suggests that pneumococcal conjugate vaccines will need ongoing adaptation.

Spread of Meropenem-ResistantStreptococcus pneumoniaeSerotype 15A-ST63 Clone in Japan, 2012–2014

“…According to previous molecular studies, most serotype 15A isolates belonged to ST63, which has been named Sweden 15A -25 (PMEN15A-25) in the PMEN and shows strong macrolide resistance. The PMEN database and previous studies regarding serotype 15A-ST63 strains indicate that most isolates that were closely related to PMEN15A-25 were susceptible (MIC < 0.06 mg/L) or showed intermediate resistance (MIC 0.12–1.0 mg/L) to penicillin ( 5 , 9 , 10 , 32 ). Although data for meropenem susceptibility of these isolates are limited ( 5 , 7 ), no studies have demonstrated the meropenem resistance of this strain.…”

Investigation of the susceptibility trends in Japan to fluoroquinolones and other antimicrobial agents in a nationwide collection of clinical isolates: A longitudinal analysis from 1994 to 2016

“…The strain with LVFX MIC of 64 mg/mL was also resistant to ABPC, CTRX, and MINO, and intermediate to STFX, IPM and CAM. There are reports in Japan and the United Kingdom that, after the introduction of pneumococcal conjugate vaccines, multidrug-resistant serotype 15A increased [22,23], thus, there are concerns about multidrugresistant S. pneumoniae. QRDR alteration was found in 30.8% (61/198 strains) and 87.5% (21/24 strains) of LVFX-susceptible strains with LVFX MIC of 0.5e2 mg/mL in S. pyogenes and H. influenzae, respectively.…”

Impact of existing vaccines in reducing antibiotic resistance: Primary and secondary effects

“…As ABR remains a significant selective advantage for surviving pneumococcal lineages post-PCV10 and PCV13, it is instructive to consider the acquisition of ABR in the remaining nonvaccine types (NVTs). Subsequent to the introduction of PCV13, ABR has now In vaccinated children, 14.5% fewer amoxicillin prescriptions were given during the period of influenza virus circulation compared with other time periods (30) been observed in cases of disease due to previously less common serotypes such as 15A (22) and 35B (23). For example, in Sweden ABR among invasive pneumococci has traditionally been among the lowest observed in Western countries.…”