Impact of the revised penicillin susceptibility breakpoints for Streptococcus pneumoniae on antimicrobial resistance rates of meningeal and non-meningeal pneumococcal strains
ABSTRACT In January 2008, the Clinical Laboratory Standard Institute (CLSI) revised the Streptococcus pneumoniae breakpoints for penicillin to define the susceptibility of meningeal and non-meningeal isolates. We studied the impact of these changes. In addition, the pneumococcal resistance rate to other antimicrobial agents was reviewed.
Laboratory data on peumococcal isolates collected retrospectively from hospitalized children in tertiary care hospital in Riyadh, Saudi Arabia from January 2006 to March 2012.
Only sterile samples were included from cerebrospinal fluids, blood, sterile body fluids and surgical tissue. Other samples such as sputum and non sterile samples were excluded. We included samples from children 14 years old or younger. The minimum inhibitory concentration (MIC) for penicillin, cefuroxime, ceftriaxone and meropenem were determined by using the E-test, while susceptibility to erythromycin, cotrimoxazole and vancomycin were measured using the disc diffusion methods following the guideline of CLSI.
Specimens were analyzed in two different periods: from January 2006 to December 2007 and from January 2008 to March 2012. During the two periods there were 208 samples of which 203 were blood samples. Full penicillin resistance was detected in 6.6% in the first period. There was decrease in penicillin nonmeningeal resistance to 1.5% and an increase in resistance in penicillin meningeal 68.2% in the second period (P=.0001). There was an increase in rate of resistance among S pneumoniae isolates over the two periods to parenteral cefuroxime, erythromycin and cotrimoxazole by 34.6%, 35.5% and 51.9%, respectively. Total meropenem resistance found 4.3% and no vancomycin resistance was detected.
The current study supports the use of the revised CLSI susceptibility breakpoints that promote using penicillin to treat nonmeningeal pneumococcal disease, and might slow the development of resistance to broader-spectrum antibiotics.
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ABSTRACT: Here, we report a laboratory-based study of Streptococcus pneumoniae recovered from patients with meningitis in Rio de Janeiro State, Brazil. The aim of this study was to determine the evolution of β-lactam resistance, antimicrobial susceptibility pattern, serotypes, and genetic diversity of S. pneumoniae, isolated from meningitis patients between 2000 and 2008. A total of 264 S. pneumoniae recovered from patients between 2000 and 2008 were included. Susceptibility testing (E-test) of S. pneumoniae showed resistance to penicillin, ceftriaxone, oxacillin, cotrimoxazole, tetracycline, ofloxacin, erythromycin, chloramphenicol, and rifampicin. Penicillin resistance (PEN-R, minimal inhibitory concentration [MIC] ≥ 0.12 μg/mL) increased from 8% of isolates in 2000-2002, to 12% in 2003-2005, and to 20% in 2006-2008. Ceftriaxone resistance (MIC ≥ 1.0 μg/mL) was detected among some PEN-R isolates (13%) from 2004 onward. Within the PEN-R isolates, serotypes that are included in 10-valent pneumococcal conjugate vaccine predominated (90%), and resistance was detected mostly in isolates of serotypes 14 (61%), 23F (16%), 6B (10%), and 19F (3%). Multilocus sequence typing showed that 52% of the PEN-R isolates, and 89% of those with MICs ≥ 0.5 μg/mL, were sequence type (ST)-156 or single-locus variants of this ST (ST-557 or ST-4388); all of these isolates were serotype 14 and were assigned to the Spain-3 clone. β-lactam resistance increased recently among cerebrospinal fluid isolates and was mainly due to the surge of the ST-4388, a previously undescribed gki single-locus variants of ST-156. Regional surveillance is shown to be essential to provide optimal antimicrobial therapy, monitor highly successful clones, and formulate adequate vaccination strategy.The Pediatric Infectious Disease Journal 08/2011; 31(1):30-6. DOI:10.1097/INF.0b013e31822f8a92 · 3.14 Impact Factor
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ABSTRACT: During a period of ten months, minimum inhibitory concentrations (MICs) to seven antimicrobial agents of 150 clinical isolates of Streptococcus pneumoniae were determined at a teaching hospital in Riyadh, Saudi Arabia. Twenty-two (14.7%) isolates showed relative resistance to penicillin. High-level resistance to penicillin was not observed in any of the isolate. Seventeen (11.3%) isolates were resistant to erythromycin, and 31 (20.7%) to tetracycline. Multiple resistance was observed in 21 (14%) isolates. Decreased resistance to ceftriaxone was also found in two (1.3%) isolates. Isolates with relative resistance to penicillin were significantly associated with higher rates of resistance to other antibiotics than were penicillin-susceptible isolates. This was also true for multiple resistance encountered in both groups.International Journal of Antimicrobial Agents 10/1995; 6(1):37-41. DOI:10.1016/0924-8579(95)00018-4 · 4.26 Impact Factor
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