Specific PCR Assay for Rapid and Direct Detection of Neisseria meningitidis in Cerebrospinal Fluid Specimens

BACKGROUND

Neisseria meninigitidis is one of the most frequently encountered microorganisms associated with central nervous system infections. The aim of this study was to evaluate a PCR-based assay for specific and rapid detection of N. meninigitidis in CSF specimens.

METHODS

Since April 2002 to July 2006, 130 CSF specimens were collected from patients suspected of having bacterial meningitis. Bacterial isolation and identification was carried out according to the standard bacteriological methods. The PCR was used to amplify a 101bp fragment of capsular transport gene A (ctrA) of N. meningitidis.

RESULTS

PCR yielded an amplified product with the expected size of 101 base pair fragment. Sensitivity test proved 500 ng of N. meningitidis DNA as the final detection limit and specificity test revealed no cross-reaction for a wide range of respiratory pathogenic organisms.

CONCLUSION

The PCR assay was more sensitive than the bacterial culturing. It might be possible to apply this procedure for rapid diagnosis of meningococci in clinical samples.

Rapid detection of Borrelia burgdorferi strains by nested polymerase chain reaction

This study was carried out to evaluate the nested PCR for specific detection of different strains of B. burgdorferi. Five strains of B. burgdorferi including ACA-1, B-31, 2B45, 3B45, 7B49 obtained from different countries were used in this study. The strains of B. hermsii, Escherichia. coli and T. pallidum were also included as control strains. Two pairs of nested PCR primers were used to amplify the gene encoding the Osp-A protein of B. burgdorfer under standard PCR condition. In a two stage procedure, nested PCR yielded a positive reaction for five tested strains of B. burgdorferi. None the strains including B. hermsii, E. coli and T. pallidum showed positive reaction when used as control strains in PCR. In conclusion, nested PCR showed acceptable specificity for rapid detection ofB. burgdorferi.

A survey of traditional Iranian food products for contamination with toxigenic Clostridium botulinum

This study aimed to determine the rate of Clostridium botulinum contamination in some traditional Iranian food products (cheese, kashk and salted fish) and evaluate the efficacy of the mouse bioassay method in detection of C. botulinum toxins in these foods. A total of 131 samples (57 cheese, 11 kashk and 63 salted fish) were collected and examined to determine the rate of contamination by C. botulinum. Standard monovalent anti-toxins were used to determine the types of toxin. C. botulinum bacteria were detected in 4.58% of the examined samples (1.52% of cheese and 3.06% of salted fish samples). While no contamination was detected in the kashk samples, C. botulinum types A and E were found to be dominant in cheese and salted fish samples, respectively. These results indicate-some traditional Iranian foods may be contaminated with different types of C. botulinum, and the consumption of these products, either raw or cooked, may contribute to food-borne intoxications.

The study of prevalence and antimicrobial susceptibility of tracheal bacterial strains isolated from pediatric patients

The aim of this study was to investigate the prevalence and antimicrobial susceptibility of bacterial strains isolated from tracheal specimens obtained from pediatric patients admitted to a major children hospital in Tehran, in 2007. Tracheal specimens were cultured on the appropriate bacteriological media. Bacterial isolates were identified by standard biochemical and serological tests. Antimicrobial susceptibility testing was performed according to Clinical and Laboratory Standards Institute (CLSI) guidelines. Pseudomonas spp. was identified as the most prevalent bacterial isolate (32%) followed by Staphylococcus aureus (27.6%). Thirty strains (16%) were identified as Klebsiella spp., 18 (9.6%) as Enterobacter spp. and the rest belonged to coagolase negative Staphylococci, Streptococcus viridans, Acinetobacter spp., Escherichia coli and Neisseria spp. All Pseudomonas spp. were resistant to ampicllin, kanamycin and ceftizoxime. Staphylococcus and Klebsiella spp. showed high degree of resistance to 40% of examined antibiotics.

Spinal tuberculosis: a major public health hazard in Isfahan

The purpose of this study is to review of spinal tuberculosis in three hospitals in Isfahan of Iran. We carried out a cross sectional study of 630 patients with tuberculosis and identified 100 patients with spinal involvement in the three hospitals. Tuberculosis was diagnosed based on one of a compatible clinical picture. A radiographic study of the spine with suspicious signs and skin tested were performed for each patient. Demographic data, sign, symptoms and site of spinal involvement were recorded. In all patients, a chest X ray and sputum smear and culture was performed for rouling out of pulmonary tuberculosis. Out of the 100 patients with spinal tuberculosis, 58% were male and 42% were female. Main symptoms were spinal deformity, local tenderness and neurologic deficits. Fever and constitutional symptoms were in 80% of cases. Only 68% had a positive tuberculin skin test. Three percent involvement were the upper thoracic spine, 23% the lower thoracic spine, 69% also the lower thoracic, T12 and upper lumbar spines, (thoracolumbar) and 5% the cervical spine. 40 cases underwent bone biopsy that 25% had a positive smear, whereas 62.5% had a positive culture. Histologic findings suggestive of tuberculosis involvement of the bone were found in 37 of the 40 biopsies. The most common age for spinal involvement were 20-40 years (p < 0.05). Spinal tuberculosis may be missed in patients with no evidence of pulmonary. No pathognomonic imaging signs allow tuberculosis to be readily distinguished from other conditions. In this here, we discuss about clinical and histopathological findings in patients with spinal tuberculosis.

Latex gloves allergy in dental workers, Iran

Dermal-respiratory reactions to latex glove is a common problem and sometimes life threatening. Some of the health related past histories such as hand dermatitis, atopy and food allergy increase the probability of these reaction. The purpose of this study was to evaluate reactions to latex gloves amongst dental workers in military dental health centers. In this cross-sectional descriptive survey, dental workers with minimum three months length of employment and most often use of latex gloves were asked to fill standard questionnaire regarding latex related clinical manifestation and personal medical history and predisposing factors. Those with clinical problems did Skin Prick Test (SPT). In this study 330 personnel were assessed. The mean age and length of employment was 31.6 and 8 years, respectively. The most occupation was dentistry. A total of 232 subjects (70.3%) reported latex gloves-allergic symptoms. 72 (21.8%) of persons have history of atopy and food allergy was seen in 114 (34.5%). 63 (19.1%) of subjects reported history of hand dermatitis. All of these had positive regression with allergic responses. Among 73 (34%) symptom positives, 28 (38%) had positive result of SPT. In this survey, the prevalence of allergic reactions is higher than similar studies, which may be due to type of gloves, lack of preemployment assessments and other factors. Because of relationship between allergic reactions to latex gloves and some medical histories, it seems to be necessary for preemployment evaluation and periodic health surveillance of dental workers.