الفهرس 
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Abstract
The Streptococci is gram-positive spherical bacteria (cocci) that characteristically form pairs and chains during growth. They are widely distributed in nature. Some are members of the normal human flora for, e.g. commensal Streptococci of the oral cavity, are common causes of sub-acute bacterial endocarditis, others are associated with important human disease attributable in part to injection by Streptococci, in part to sensitization to them. Streptococci elaborates a variety of extracellular substances and enzymes (Khan, Sharma et al. 2012).
These drugs (erythromycin, azithromycin, clarithromycin, roxythromycin, ketolide and telithromycin) bind to the 50 s subunit of the ribosome, and the binding site is a 23S rRNA. They may interfere with formation of initiation complexes for peptide chain synthesis or may interfere with aminoacyl translocation reactions. Some Macrolide-resistant bacteria lack the proper receptor on the ribosome (through methylation of the rRNA). This may be under plasmid or chromosomal control. Streptococcus species is uniformly susceptible to penicillin. However, macrolides remain drug of choice for patient allergic to penicillin. S. pneumoniae is known in medical microbiology as the Pneumococcus, referring to its morphology and its consistent involvement in pneumococcal pneumonia (Khan, Sharma et al. 2012).
The aim was to study the prevalence of macrolide resistance among the isolate and evaluate the degree of resistance. And also to detect the phenotypic pattern of macrolide resistance.
The present study was carried out in Sohag university hospital in the period between October 2017 and April 2018, 100 samples were collected from chest and E.N.T departments to detect macrolide resistant strains in streptococci isolated from patients with respiratory tract and ear
infections. The clinical specimens included sputum from patients with respiratory tract infection (62 specimens), and pus from patients with ear infection (38 specimens). Out of the 100 samples 83 isolates yielded pure growth of streptococci. Out of the 83 isolates which yielded pure growth of streptococci, 54were streptococcus viridians and 29 were streptococcus pyogenes. Resistant genes were detected in 27 isolates of streptococcus viridians and 25 isolates of streptococcus pyogenes.
54% of our samples result gram positive diplococci, 38% result gram positive cocci and only 8% result gram positive bacilli. Regarding arrangement, we found that 46% of samples arranged in pairs, 29% arranged in chains, 9% arranged in clusters, 8% arranged in short chains and pairs and also 8% not arranged in specific shape.
When D test made in this study, we found that only 37.35% of our cases were sensitive and 62.65% were resistant. Furthermore, when phenotyping of D test for resistant samples made in our study, we found that 73% of cases were constitutive, 19.23% of them were M-phenotype, and 7.69% were inducible phenotype.
As regards E test, ( by determination of MIC of erythromycin ) 96.15% of our cases were resistant, only 3.85% were sensitive.
Regarding type of resistant genes in this study, 88.46% of cases had ERM B, 7.69% had MEF A, and 3.85% had Combined ERM B & MEF A. When we compare between our 2 studied groups regarding type of resistant genes, we found that all ear discharge group had ERM B, but sputum group had each of ERM B and MEF A (73.91%, 17.39% respectively) with significant difference (p =0.01).
Furthermore, when we compare between 2 estimated organisms in our study regarding type of resistant genes, we found that 92.59% of cases had Strept. Viridans had ERM B and 7.41% had MEF A, however 84.00% of cases had Strept. Pyogenes had ERM B, 8% had MEF A and 8% had combined ERM B & MEF A with non significant difference (p =0.32).
In this study, regarding relation between genotype and phenotype, we found that 94.7% of constitutive phenotype had ERM B, and 5.26% had combined ERM B & MEF A, otherwise, 100% of inducible phenotype had ERM B. On the other hand, 60% of M-phenotype had ERM B, and 40% had combined ERM B & MEF A.
Conclusion
Our findings suggest that the overall population of macrolide-resistant Streptococci from respiratory tract and ear infectionsin sohag universityhospital is 62.65%. In our study, we found that 73% of cases were constitutive phenotype, 19.23% of them were M-phenotype and 7.69% were inducibleMLSB phenotype,consequently,macrolides would not be the first drug of choice for treatment of tonsillitis and other s.pyogenes related diseases,physicians and recearchers need to take into consideration the macrolide resistance of some strains of s.pyogenes, andmacrolide GASresistance must be closely monitored in each country . furthermore, the use of rapid groupA antigen test must be followed by sensitivity testing when the patient is allergic to B- lactam agent.