Antimicrobial susceptibility of select respiratory tract pathogens in Dakar, Senegal

Abstract

Background : Haemophilus influenzae, Moraxella catarrhalis, Streptococcus pyogenes, and Streptococcus pneumoniae are the most common causative agents of respiratory tract infections (RTIs). The increase in resistance to current antibacterial agents highlights the need to monitor the resistance pattern of these bacterial pathogens. Methodology: In this study, we assessed the antibacterial susceptibility of these pathogens causing respiratory tract infections in Dakar, Senegal, during 2007. A total of 290 bacterial isolates (75 H. influenzae, 10 M. catarrhalis, 105 S. pneumoniae, and 100 S. pyogenes) were collected. Results and Conclusions: All H. influenzae isolates were susceptible to amoxicillin/clavulanic acid, ofloxacin, clarithromycin, cephalosporins, and macrolides. Overall, 26.7% of H. influenzae isolates were completely resistant to ampicillin. Among the M. catarrhalis isolates, 30% were resistant to ampicillin. All the isolates of H. influenzae and M. catarrhalis that were resistant to ampicillin were beta-lactamase producing strains. Among the S. pneumoniae isolates, 33.3% isolates exhibited intermediate susceptibility to penicillin G, and one isolate was completely resistant. All five isolates that were resistant to erythromycin expressed the M phenotype. S. pyogenes exhibited high susceptibility to all other antibiotics, except tetracycline. Our study suggests that except for M. catarrhalis, all other bacterial isolates are susceptible to cephalosporins, macrolides, and fluroquinolones.

Antibiotic resistance of bacteria responsible of acute respiratory tract infections in children

“…This suggests that beta-lactamase production could be the major mechanism of antibiotic resistance for these organisms. A high rate (100%) of H. influenzae resistance to cotrimoxazole was observed, contrasting therefore with results reported by Gueye et al, in Dakar in 2009 (10).…”

“…In our study, high resistance rate (31.3%) of S. pneumoniae to penicillin G was observed, which is similar to data previously reported in a study conducted by Gueye and al. in Dakar (10). However, our data are not consistent with results reported in Sub-Saharan Africa in which resistance level remained below 6% overall (12).…”

“…Resistance to sulfamethoxazole/trimethoprim were detected in all isolates tested. This is in disagreement with results from a study conducted in Dakar in 2009 (10). However, increasing resistance rates to sulfamethoxazole/trimethoprim have been reported between 2003 and 2006 in the East Africa region (9).…”

Disease Manifestations and Pathogenic Mechanisms of Group A Streptococcus

“…The penicillin susceptibility of GAS has not altered significantly in over 50 years of use of penicillin as a treatment for GAS infection (467). Reported MIC 90 values of penicillin are a median of 0.016 mg/liter and a range of 0.0025 to 0.032 mg/liter (467)(468)(469)(470)(471). There has been only a single report of naturally occurring penicillin-tolerant GAS (472); however, this report has not been independently confirmed.…”

Antimicrobial susceptibility of bacterial pathogens associated with community-acquired respiratory tract infections in Asia: report from the Community-Acquired Respiratory Tract Infection Pathogen Surveillance (CARTIPS) study, 2009–2010

“…A surveillance study of community-acquired respiratory pathogens during the 2005-2006 respiratory season in the USA reported that the rate of resistance to azithromycin was 34% [16], and data from Senegal in West Africa [17] indicated that <5% of all S. pneumoniae isolates were resistant to macrolides. In Japan [6], however, rates of erythromycin-resistant S. pneumoniae strains ranged from 77.2% to 81.9% during the 1999-2004 respiratory seasons, and MIC 50 values for macrolides against S. pneumoniae were 128 mg/L (azithromycin and erythromycin) and 64 mg/L (clarithromycin).…”