role of rapid testing and clinical decision in the diagnosis of human influenza A H1N1 infection

To evaluate the role of the rapid influenza diagnostic test [RIDT] and clinical decision in the diagnosis of H1N1. In November 2009, 290 suspected influenza patients were examined for H1N1 during an outbreak in Riyadh, Saudi Arabia. Nasopharyngeal swabs were analyzed using Directigen EZ Flu A+B kit. Monoclonal anti-human influenza A/B and reverse transcription- polymerase chain reaction [RT-PCR] were used. Positive and negative controls were used in each run of specimens. Validity indices were calculated for RIDT and clinical diagnostic criteria. The sensitivity and specificity of RIDT were 40.5% [95% confidence interval [CI]: 33.0-48.5], and 94.5% [95% CI: 88.6-97.6]. The sensitivity of clinical decision was 66.3% [95% CI: 58.4-73.4], and the specificity was 65.4% [95% CI: 56.3-73.4]. The sensitivity of clinical decision was higher in early presenters [79.2%; 95% CI: 57.3-92.1]. The RIDT sensitivity was higher in younger patients [48.4%; 95% CI: 35.7-61.3]. The positive predictive value [PPV] was 90.4% [95% CI: 80.7-95.7] for RIDT, and 71.1% [95% CI: 63.1-78.0] for clinical decision. The PPV for RIDT was greater for older [94.7%; 95% CI: 80.9-99.1] and late [90.7%; 95% CI: 76.9-97.0] presenters. The adjusted odds ratio for clinical decision was significant for cough, headache, and fatigue. The RIDT can be useful in epidemics and high prevalence areas, whereas clinical decision, and RT-PCR complement the diagnosis of H1N1 in any setting

Helicobacter pylori virulence markers in gastroduodenal disorders. detection of cytotoxin-associated gene A and vacuolating cytotoxinassociated gene A genes in Saudi patients

To detect the presence of virulence markers cytotoxin-associated [cagA] and vacuolating cytotoxinassociated [vacA] genes in gastric biopsy specimens of patients with gastroduodenal disorders. This study was conducted at the Department of Pathology, King Khalid University Hospital, Riyadh, Kingdom of Saudi Arabia between March 2008 and February 2009. A total of 118 gastric biopsy specimens from 81 males and 37 females [mean age: 55 +/- 18 years] with histological evidence for the presence of Helicobacter pylori [H. pylori] were included in the study. The H. pylori cagA and vacA genes were detected using polymerase chain reaction-enzyme-linked immunosorbent assay technique. Both H. pylori cagA and vacA genes were detected in 60 [51%] patients. Forty-one [35%] patients had active chronic gastritis, 22 [54%] harbored cagA, and 25 [61%] had vacA gene. Twenty-six [22%] patients with duodenal ulcer, 14 [54%] had cagA, and 15 [58%] had vacA genes. Eighteen [15%] patients had active acute gastritis, 8 [44%] were carrying cagA gene, and 12 [67%] had vacA gene. The cagA and vacA genes co-existed in all the 17 [100%] patients with adenocarcinoma. These genes coexisted in 44% biopsies from active acute gastritis, and 46% each in duodenal ulcer and active chronic gastritis. The cagA and vacA genes as H. pylori virulence markers were detected in gastroduodenal disorders, and their remarkably high co-existence in adenocarcinoma prompt further investigations for evaluating H. pylori as a direct carcinogen

validation study comparing the sensitivity and specificity of the new Dr. KSU H1N1 RT-PCR kit with reAl time RT-PCR for diagnosing influenza A [H1N1]

A new test [Dr. KSU H1N1 RT-PCR kit] was recently developed to provide a less expensive alternative to reAl time reverse transcriptase-polymerase chain reaction [RT-PCR]. We report the findings of a validation study designed to assess the diagnostic accuracy, including sensitivity and specificity, of the new kit, as compared to reAl time RT-PCR. Cross-sectional validation study conducted from 18-22 November 2009 at a primary care clinic for H1N1 at a tertiary care teaching hospital in Riyadh. Nasopharyngeal swab samples and data on socio-demographic characteristics and symptoms were collected from 186 patients. Swab samples were sent to the laboratory for testing with both reAl time RT-PCR and the new Dr. KSU H1N1 RT-PCR kit. We measured the sensitivity and specificity of the new test across the entire sample size and investigated how these values were affected by patient socio-demographic characteristics and symptoms. The outcomes of the two tests were highly correlated [kappa=0.85; P<.0001]. The sensitivity and specificity of the new test were 99.11% and 83.78%, respectively. The sensitivity of the new test was affected only minimally [96%-100%] by patient characteristics and number of symptoms. On the other hand, the specificity of the new test varied depending on how soon patients were tested after onset of symptoms [100% specificity when swabs were taken on the first day of the symptoms, decreasing to 75% when swabs were taken on or after the third day]. The specificity of the new test also increased with increasing body temperature. The new test seems to provide a cost-effective alternative to reAl time RT-PCR for diagnosing H1N1 influenza. However, further testing may be needed to verify the efficacy of the test in different settings and communities

Antimicrobial activity of tigecycline against bacterial isolates from intensive care units in a teaching hospital in central Saudi Arabia

To test the activity of tigecycline against bacterial isolates including multi-drug resistant [MDR] gram negative and gram positive organisms from intensive care patients. Clinically significant gram positive and MDR gram negative isolates from specimens of patients in the intensive care units of King Khalid University Hospital [KKUH], Riyadh, Kingdom of Saudi Arabia between November 1, 2006 and December 31, 2008 were tested against tigecycline by disc diffusion [DD] method. In some isolates, the minimal inhibitory concentration was carried out by E-test method. Some of the gram negative isolates, and gram positive isolates were tested using both methods. The study was approved by the hospital ethics committee. All the 83 gram positive organisms tested by both DD and E-test were susceptible to tigecycline. Two hundred and fifty-four MDR gram negative isolates were tested for susceptibility to tigecycline. Of these 176 tested by DD, 159 [90%] were susceptible, 6 [3.4%] were resistant, and 11 [6.2%] were intermediately susceptible [data are not the same in table 3]. From the 188 isolates tested by E-test, 140 [74.4%] were susceptible, 35 [18.6%] were resistant, and 13 [6.9%] showed intermediate susceptibility. For comparison between the methods, 109 isolates of the MDR gram negative organisms were tested by both E test and DD. The difference between the 2 methods was not significant. Tigecycline was active against gram positive and most MDR gram negative isolates from patients in medical and surgical intensive cases in KKUH. There was no significant difference between the DD and E-test methods for susceptibility testing of tigecycline against these isolates