Molecular characterization of CTX-Mβ-lactamases among Klebsiella pneumoniae isolated from patients at Tehran hospitals

Purpose: Plasmid-encoded CTX-M-group of extended-spectrum β-lactamases (ESBLs) represent a significant and rapidly emerging problem in most part of the world. The aim of the present study was to describe the prevalence of CTX-M producing Klebsiella pneumoniae at Tehran hospitals. Materials and Methods: Clinical isolates of K. pneumoniae (n=250) were collected from 10 hospitals of Tehran. Susceptibility to antimicrobial agents, MIC of cefotaxime and ESBLs production of collected isolates were detected. All ESBL-producing isolates were screened for bla_CTX-M genes using PCR and DNA sequencing. Molecular typing of bla_CTX-M harboring isolates was performed by Pulsed–field gel electrophoresis assay. Results: Of 250 K. pneumoniae clinical isolates, 102 isolates revealed ESBLs – phenotype. PCR assay and sequencing detected bla_CTX-M genes in 71.5% (n= 73) of ESBL-producing isolates. The prevalence of CTX-M -I and CTX-M-III clusters among these isolates was 35.61% (n=26) and 21.9 % (n=16) respectively. Coexistence of CTX-M -I and CTX-M-III clusters was found among 42.5% (n= 31) of isolates. Of 102 isolates that were positive in the phenotypic confirmatory test (PCT), 29 isolates (28.4%) did not produce any amplicons in PCR for bla_CTX-M gene. The results of PCR for CTX-M -II and CTX-M-IV clusters were also negative. Analysis of the 31 CTX-M producing K. pneumoniae isolates by PFGE typing showed 26 distinct patterns. Conclusions: The bla_CTX-M genes are widespread among Iranian isolates of K. pneumoniae. PFGE demonstrated the high diversity of K. pneumoniae harboring bla_CTX-M in our study.     

Evaluation of CD11b expression on peripheral blood neutrophils for early detection of neonatal sepsis

Neonatal sepsis is a disease of infants who are less than 1 month of age. These infants are clinically ill, and their blood culture are positive for bacteria. The reported incidence of neonatal sepsis for all infants is 1 to 10 per 1000 live births. The mortality rate is 4.2-26%. The clinical signs are not specific and diagnosis of neonatal sepsis is one of the most difficult tasks in clinical medicine. The aim of this work was determination of CD11b sensitivity and specificity for early detection of neonatal sepsis. We studied 65 neonates with gestational age of 27 to 38 weeks who were suspected for sepsis within the 28 days of life. Whole blood was obtained from neonates to determine CD11b expression on peripheral blood neutrophils by flow cytometry. C-Reactive protein (CRP) was measured qualitatively. Neonates were divided into two groups. Classification was based on the result of the blood culture. In the sepsis group all of the neonates (n=8) showed positive blood culture and clinical symptoms. In the suspected group (n=57) the neonates showed clinical signs but blood cultures were negative. Sensitivity and specificity of CD11b were 75%, 100% respectively. Also positive and negative predictive values of CD11b were 100% and 86% respectively. Results of present study and previous studies showed that measurement of neutrophil surface markers can be useful for diagnosis of infection in the early phases. Also, the quantitative measurement of CRP in addition to CD11b further enhances the ability to diagnose infections and improves sensitivity and negative predictive value by 100%.     

Comparison of Classic Sweat Test and Crystallization Test in Diagnosis of Cystic Fibrosis

Objective

Sweat chloride measurement is considered a standard diagnostic tool for cystic fibrosis (CF). This study was performed to compare sweat chloride values obtained by quantitative pilocarpine iontophoresis (classic test) with sweat crystallization detected by direct observation of a drop of perspiration under light microscopy in patients with and without CF.

Methods

The tests using both techniques were performed simultaneously in patients with and without CF. Cutoff values of ≥60 mmol/L of chloride concentration for the classic sweat test was considered for diagnosis of CF. In crystallization method, observation of typical dendritic forms of salt crystals under light microscopy was interpreted positive.

Findings

Sixty patients suspected to CF (31 males and 29 females) with age range of 9 months to 2 years underwent the sweat test using both techniques. Median sweat chloride values was 26.13+10.85 in group with negative and 72.76+12.78 mmol/L in group with positive sweat test, respectively. All the patients who had positive sweat test in classic method showed typical dendritic forms of salt crystal in sweat crystallization test, which provided the test with 100% sensitivity (95%CI: 93.1–100). Only one of the 31 subjects with negative results for classic sweat test had positive result for crystallization sweat test, which provided the test with 96.7% specificity (95%CI: 92.9–100). Time spent to perform the crystallization test was significantly shorter than the classic method whereas its cost was also lower than the second method.

Conclusion

There was a good correspondence between two studied methods of sweat test. These results suggested the sweat crystallization test as an alternative test for detecting CF disease with high sensitivity and specificity.     

Comparing Oral Route Paraffin Oil versus Rectal Route for Disimpaction in Children with Chronic Constipation; a Randomized Control Trial

Objective

Functional constipation is a common and challenging problem in pediatrics. Fecal disimpaction prior to maintenance therapy is recommended to ensure successful treatment. The aim of this study was to compare the efficacy and patient''s compliance of the two methods of paraffin oil administration (oral and rectal route) with the purpose of disimpaction in treatment of children with functional constipation.

Methods

A total of 80 children (49 males and 31 females) aged 1–12 years, with functional constipation according to Rome III criteria, whose rectal examination confirmed fecal impaction were divided into two groups randomly. Group I received 3 ml/kg/day paraffin oil orally and group II received 3ml/kg/day paraffin oil rectally during 3 consequent days. Successful treatment was defined as no detectable fecal impaction in rectal examination after at most 72 hours. Patient compliance and family satisfaction also was evaluated using a scored questionnaire.

Findings

Response to the treatment in both groups was with 92.5% and 82.5% in group I and II, respectively. So, there was no significant difference between the two methods of therapy. Family satisfying and compliance were obviously more achieved in group 1 (87.5% vs 57.5%) than in Group 2 (P<0.001). No parents in group I complained about type of treatment while 12.5% of parents in group II were unsatisfied with the mode of paraffin oil administration. The most common side effect of paraffin oil in both groups was anal oil seepage (27.5%). Nausea and abdominal pain were more common side effects in group 1 and 2 respectively.

Conclusion

It seems that using paraffin oil per oral route in comparison with rectal route could be a preferred option for disimpaction in children causing less anxiety to the family.     

Factors affecting the number of lymph nodes retrieved in colorectal cancer specimens

Background Staging of colorectal cancer is dependent on the number of lymph nodes in a surgical specimen that are positive for metastatic cancer. It is generally recommended that a minimum of 12 lymph nodes be examined to ensure adequate staging. It is unclear which factors specifically contribute to variation in the number of lymph nodes retrieved from surgical specimens. This study aims to understand the factors affecting the number of lymph nodes identified in surgical colorectal cancer specimens. Methods A total of 264 retrospectively collected cases of colorectal cancer surgically treated at the University Health Network in Toronto from 2004 to 2006 were analyzed. We used univariate analyses of variance (ANOVA), and univariate and multivariable linear and logistic regression analyses to study variation in the lymph node number associated with a variety of explanatory variables. Results The average number of lymph nodes retrieved per case was 18.1, with 70 (26.5%) cases containing fewer than 12. Variation in the lymph node number was greatest between different pathology assistants (p = < 0.001). The mean number of nodes retrieved by different pathology assistants ranged from 12.6 to 29.7. On average, surgery for recurrent cancer removed 6.0 (95% CI 1.2 to 10.9, p = 0.02) fewer lymph nodes than for primary cancer. Each additional year of patient age was associated with retrieval of 0.1 (95% CI 0.04 to 0.2, p = 0.005) fewer nodes, and rectal cancer specimens had 2.7 (95% CI 0.04 to 5.4, p = 0.05) fewer lymph nodes than colon cancer specimens. Conclusion Most of the variation in the number of lymph nodes identified in surgical specimens from colorectal cancer operations was accounted for by differences between pathology assistants. Presented at the SAGES Scientific Session April 18–22, 2007 Las Vegas, Nevada