Phenotype and genotype of some clinical group B streptococcus isolates resistant to erythromycin in Egypt

The aim of the study was to determine susceptibility of group B streptococci [GBS] to commonly used antibiotics and to determine the phenotype of macrolide resistance correlating it with the genotype. 220 group B streptococcus strains were subjected to antibiotic sensitivity disc diffusion method to penicillin, ampicillin, ceftriaxone, tetracyclines, erythromycin [E] and clindamycin [CD]. Erythromycin resistance phenotype was done by double disc diffusion test. Erythromycin resistance mefA, ermB, and ermTR genes were determined using multiplex PCR. The results revealed that all strains were sensitive to penicillin, ceftriaxone and ampcillin. 161 [73%], 38 [17%] and 24 [11%] strains were resistant to tetracyclines, erythromycin and clindamycin respectively. 15 [39.5%] were resistant to E alone [M phenotype]. M phenotype strains were associated with mefA gene. 23 [60.5%] isolates were resistant to both E and clindamycin [CD]. 9 [23.7%] strains were inducibly resistant to clindamycin [iMLSB] and all had ermTR gene.. 14 [36.8%] were constitutively resistant to clindamycin [cMLSB]. cMLSB strains have different genotypes. 7 strains were ermB genotype. 4 strains were ermTR genotype. 2 strains had both ermB and ermTR genes while only one strain had both ermB and mefA genes. Only 1 strain was resistant to clindamycin but sensitive to E. MefA was detected in 16 [42%] E resistant strains. ErmTR was also detected in 16 [42%] E resistant strains. ErmB was detected in 10 [26%] E resistant strains. 31[82%] E resistant strains contain single resistance gene while 7[18%] resistant strains contain more than one resistance gene. The study findings conclude that GBS isolates remain uniformly susceptible to penicillin and ampicillin but he erythromycin resistance has reached substantial level. The study recommends that testing of susceptibility to erythromycin and clindamycin by double disc diffusion method should be performed in individual cases when considered as alternatives for prophylaxis and treatment of GBS infection or colonization because strains with inducible MLSB cannot be detected with the conventional disc diffusion method

Impact of pattern of antibiotic resistance on outcome of gram negative induced spontaneous bacterial peritonitis

Spontaneous bacterial peritonitis [SBP] is a bacterial infection of ascitic fluid, which is a frequent and severe complication of hepatic cirrhosis. A vast majority of such infections are due to enteric Gram-negative bacteria, mainly Enterobacteriaceae. The prevalence of extended spectrum beta-lactamases [ESBLs]-producing bacteria is clearly increasing, and in many parts of the world 10-40% of strains of Escherichia coli and Klebsiella pneumoniae express ESBLs. This study was conducted to detect the impact of pattern of antibiotic resistant in our community, especially ESBLs-producing E. coli and K. pneumoniae, on the outcome of SBP caused by these bacteria. Ascitic fluid samples were collecting from 52 proved cases with cirrhotic ascites complicated by SBP for examination and culture [bedside inoculation into blood-culture bottles was done]. Also, antibiotics sensitivity tests were performed. Potential ESBLs producers were subjected to detection of ESBLs by three dimensional method and Oxoid combination test [CDO2]. Positive cultures were obtained in 43 [82.7%] of examined cases, among them 40 [93%] had Gram negative bacteria [32 [80%] E.coli and 8 [20%] K. pneumoniae] and the others [7%] were Gram positive [S.aureus]. Patients with negative or Gram positive cultures were excluded from this study, and these with Gram negative one were treated and followed up until discharge or in-hospital mortality. About 27.5% of studied Gram negative isolates were ESBLs- producing [25% of E.coli and 37.5% of K.pneumoniae]. There was no statistically significant difference between three dimensional method and Oxoid combination test [CDO2] in detection of ESBLs [P>0.05]. The percentages of resistant E.coli and K.pneumoniae respectively were [43.75% and 25%] to cefotaxime, [46.9% and 25%] to ceftriaxone, [50% and 50%] to ceftazidime, [53.1% and 75%] to cotrimoxazole, [50% and 62.5%] to norfloxacin and [12.5% and 50%] to ciprofloxacin. In-hospital mortality due to SBP was 60%. After uni- and multivariate analyses, only 5 variables studied were independently associated with SBP in-hospital mortality [P<0.05]. These were: Child-Pugh score >12 [RR=3.2], having hepatic encephalopathy [RR=2.7], jaundice [RR=1.5], SBP caused by ESBLs-producing strains [RR=1.5] and serum Na<130 mmol/L [RR=1.3]. In conclusion, Gram negative SBP induced by ESBLs- producing strains -which are resistant to all 3rd generation cephalosporin and lead to abundant mortality - are prevalent and must be put in mind . Repeated check up of the pattern of resistance of these strains is indicated and searching for new alternative effective therapy for this treatable severe complication of cirrhosis is recommended. Oxoid combination test is sensitive, convenient and inexpensive method for detection of ESBLs producing organisms

Diagnosis of acute bacterial endophthalmitis by nested polymerase chain reaction

Microbiological investigations of vitreous fluid [VF] and aqueous humour [AH] samples have often failed to detect the infecting agent in infectious endophthalmitis, resulting in a clinical dilemma regarding therapy. So in this study we aim to assess the usefulness of polymerase chain reaction in the diagnosis of acute bacterial endophthalmitis. This study included forty intraocular samples [25 vitreous fluids [VF] from 25 cases of endophthalmitis and 15 samples; 7 VF and 8 AH as control from non infective patients during vitreous and cataract surgery respectively. The samples were processed for microbiological investigation [Gram stain and periodic acid schiff and culture for aerobic, anaerobic bacteria and fungi]. Nested PCR directed at the 16S rDNA using universal primers for eubacterial genome was done. The 25 cases were divided into four groups according to the initial ophthalmic procedure. PCR for eubacterial genome showed 100% correlation with 12 [48%] bacterial culture positive samples. Two samples were positive by both direct smear and PCR but negative culture. Eubacterial genome was detected in 5 [38.4%] of 13 bacterial culture negative samples. Among the 8 eubacterial PCR negative samples, one was positive for fungus infection. Only one of 15 control samples was positive for eubacterial genome. The sensitivity and specificity of PCR in relation to culture results were 100% and 93.75%. respectively. The most common organisms recovered from patients with culture proven endophthalmitis were Coagulase Negative Staphylococci [CoNS] [41.7%], S.aureus [16.7] S. viridans [16.7%], Pneumococci [8.3%], P. aeruginosa [8.3%] and E. coli [8.3%]. The most common factors predisposing to acute bacterial endophthalmitis were intraoperative complications, use of anti-metabolite [mitomycin C] and diabetes mellitus. PCR performed on aqueous humour [AH] and vitreous fluid [VF] is a reliable tool for the diagnosis of acute bacterial endophthalmitis particularly in smear and culture negative samples

role of IL-15 in inflammatory activity of patients with rheumatoid arthritis [RA]

Interleukin 15 [IL-15], a new player in the cytokine network, is produced mainly by monocytes and can be detected in the rheumatoid synovium. The aim of this study was to investigate the role of IL- 15 in patients with rheumatoid arthritis [RA]. IL-15 cytokine was measured in sera and synovial fluid [SF] of 40 patients with rheumatoid arthritis [RA] and 20 patients with osteoarthritis and only in sera of 20 healthy control using an enzyme-linked immunosorbent method. Seven American College of Rheumatology [ACR] core set measures as well as IL-15 levels were sequentially monitored at the commencement. IL-15 had been detected in sera of 16 [40%] of 40 RA patients, in two [10%] of 20 osteoarthritis [OA] patients and two [10%] of 20 healthy controls. The mean level of circulating IL-15 was significantly higher in RA patients [P < 0·001]. In SF, the mean IL-15 levels were significantly higher in RA patients [162.8 +/- 35.4] than in OA patients [32.5 +/- 5.5] [P < 0·001]. In paired samples [n=40] of sera and SF from RA patients and OA patients, IL-15 levels were higher in the SF than in sera [P < 0·001] in RA but not in OA. Rheumatoid arthritis patients with detectable IL-15 [n=25] had higher tender joint scores [P < 0·01], swollen joint scores [P < 0·001] and C-reactive protein [CRP] [P < 0·05], rheumatoid factor [P < 0.001], and long disease duration [P < 0·05] than those without [n=15]. In conclusion, IL-15 was elevated significantly in the sera and SF of patients with active rheumatoid arthritis [RA] but not on OA patients and correlated well with several parameters of RA disease activity. These observations suggest that IL-15 production may be associated with an exacerbation of RA, and then IL-15 levels could be useful to assess disease activity

Soluble L-selectin, vascular endothelial growth factor and endothelin-1 in patients with ulcerative colitis

Recent evidence increasingly suggests that ulcerative colitis [UC] is the result of dysfunctional immunoregulation manifested by an inappropriate production of mucosal cytokines. An abnormal microcirculatory system has also been implicated in its pathogenesis. The objective of this study was to assessed serum concentrations of soluble L-selectin [sL-selectin] and vascular endothelial growth factor [VEGF] and the plasma level of endothelin-1[ET-1] in the patients with UC, compared with healthy controls, and to analyze the results depending on the stage of the disease. This study was conducted on two groups of subjects, the patient group including 30 patients with active ulcerative colitis [UC], and the control group which included 15 healthy volunteers. We assessed serum sL-selectin, VEGF and Plasma ET-1 Level at the beginning of the study in patients and controls then measured again in patients after remission. The levels of sL-selectin, VEGF, and ET-1 were significantly higher in active UC than those in the controls [p < 0.001]. But in remission there was no significant difference between UC patients and controls in VEGF and ET-1 levels. We also found that serum Level of sL-selectin, VEGF, and Plasma Level of ET-1 were significantly higher in patients with active UC compared with patients in remission [p < 0.001]. In addition, it is shown that UC patients in remission have significantly lower levels of sL-selectin than controls. There was a significant positive correlation among the serum levels of VEGF and the plasma level of ET-1; that is, elevated VEGF, and ET-1 levels correlated well with each other in active UC patients [r= 0.631, p < 0.001]. The most common form of the disease observed in our patient population was of mild to moderate severity. Pro-inflammatory cytokines, including sL-selectin, VEGF, and ET-1 appear to play a significant role in the pathogenesis of ulcerative colitis [UC]. Their levels were higher during exacerbation while it is low in periods of remission in UC patients