Analysis of quinolone-resistant Streptococcus pneumoniae collected from PROTEKT studies between 2000 and 2007

Abstract number: P1684

Blackman Northwood J., Couturier C., Brown S., Morrissey I.

Objective: The genetic & geographical relationship between quinolone-resistant (QR) S. pneumoniae (SP) collected as part of PROTEKT Global & PROTEKT US was determined.

Methods: SP were collected from PROTEKT Global (47 countries worldwide; N = 41,693) & PROTEKT US (49 states; N = 55,729). MICs were determined using CLSI guidelines. Quinolone resistance determining regions (QRDR) within gyrA, gyrB, parC & parE were sequenced & multi locus sequence typing determined for QRSP by previously published methods.

Results: QR rates for both studies remained stable ~1% each year (Table). However, Italy had a steadily increasing rate of QR. Hong Kong had a very high QR rate while Massachusetts (MA), Colorado (CO), New Jersey (NJ) & New York (NY) had higher than the US average (0.9% [SD0.6]) QR rates.

Globally, QRSP were from a wide range of sequence types (ST) & clonal complexes (CC). QRSP from Hong Kong were mainly ST81 (58/71), which was found in numerous locations worldwide. ST66 was the dominant clone in Italy (58/81), most collected from a single centre. There were 3 dominant CC in the US: CC81 (67/527), CC271 (37/527) & CC439 (34/527). QRSP were represented by >23 CC & were evenly distributed across the US except for CC81 which peaked in NY & CC439 which peaked in MA. QR was due to typical QRDR mutations as previously reported.

Conclusion: QR in Hong Kong was due to the dominance of CC81, as previously reported. QR in Italy was due to the emerging resistant clone ST66, although this could be a localized outbreak as most came from 1 centre in Catania over a short period of time. QRSP in the US was due to the presence of numerous clones including CC81 & CC439. The presence of CC271 in QRSP is also important as this clone is often associated with resistance to macrolides, penicillin, tetracycline & cotrimoxazole.

This study shows QR remained very low during both studies & was caused by multiple CC in most countries.

Table 1. Total number of isolates collected (N) & %QR by Year [NT; not tested]