الفهرس | Only 14 pages are availabe for public view |
Abstract In the present study a total of 60 Streptococcus pneumoniae isolates were recovered from 178 sputum samples, they were collected from chest infected patients attending Mansoura Chest Hospital during the period from January 2016 to February 2017. The identification was based on colony, cell morphology and biochemical tests. The scanning electron microscopy revealed that all isolates were capsulated but do not show pilus in any of these isolates. Genotypic characterization was achieved by detecting some virulence genes using PCR technique. All sixty isolates harbor autolysin mediated gene (lytA). On the other hand, fifty-five (91.6%) and 13 (21.6%) of the isolates were positive for pneumolysin mediated gene (ply) and gene encoding pilus protein (rrgA) respectively. The ability of the tested isolates to form biofilm was tested by microtitration plate technique. Strong biofilm formation was observed in 21.67% of the recovered isolates. Moderate to weak biofilm formation were observed in 45% and 25% of the isolates respectively. In contrast, 8.33% were none producer. The susceptibility of tested isolates to 20 different antimicrobial agents was performed using disk diffusion method. Data obtained revealed that, resistance rate in respect to β-lactam antibiotics was ranged from 78.33% to 66.66%, penicillins and cefaclor were least effective antibiotics. However, cefoperazone and cefotaxime were most effective antibiotics. In respect to non β-lactam antibiotics; the resistance rate was ranged from 53.3% to 35%. Erythromycin, rifampicin, tetracycline, co-trimoxazole were least effective antibiotics, while linezolid and clindamycin were most effective antibiotics. Most of isolates (93%) were multidrug-resistant (MDR) and had a high MAR index value (>0.2). Using a multiplex PCR, the penicillin binding protein genes pbp1a, pbp2b and pbp2x were found in 33 (55%), 25 (41.7%) and 45 (75%) of the isolates, respectively. All isolates were contained at least one penicillin binding protein resistant gene. Thirty-two (53.3%) of isolates showed two resistance genes; pbp1a and pbp2x. Ten isolates (16.7%) showed the three resistance genes; pbp1a, pbp2b and pbp2x. |