Prevalence and molecular characterization of pertactin-deficient Bordetella pertussis in the United States.

Pertussis has shown a striking resurgence in the United States, with a return to record numbers of reported cases as last observed in the 1950s. Bordetella pertussis isolates lacking pertactin, a key antigen component of the acellular pertussis vaccine, have been observed, suggesting that B. pertussis is losing pertactin in response to vaccine immunity. Screening of 1,300 isolates from outbreak and surveillance studies (historical isolates collected from 1935 up to 2009, isolates from the 2010 California pertussis outbreak, U.S. isolates from routine surveillance between 2010-2012, and isolates from the 2012 Washington pertussis outbreak) by conventional PCR and later by Western blotting and prn sequencing analyses ultimately identified 306 pertactin-deficient isolates. Of these pertactin-deficient strains, 276 were identified as having an IS481 in the prn gene (prnIS481 positive). The first prnIS481-positive isolate was found in 1994, and the next prnIS481-positive isolates were not detected until 2010. The prevalence of pertactin-deficient isolates increased substantially to more than 50% of collected isolates in 2012. Sequence analysis of pertactin-deficient isolates revealed various types of mutations in the prn gene, including two deletions, single nucleotide substitutions resulting in a stop codon, an inversion in the promoter, and a single nucleotide insertion resulting in a frameshift mutation. All but one mutation type were found in prn2 alleles. CDC 013 was a predominant pulsed-field gel electrophoresis (PFGE) profile in the pertactin-positive isolates (203/994) but was found in only 5% (16/306) of the pertactin-deficient isolates. Interestingly, PFGE profiles CDC 002 and CDC 237 represented 55% (167/306) of the identified pertactin-deficient isolates. These results indicate that there has been a recent dramatic increase in pertactin-deficient B. pertussis isolates throughout the United States.

Caffeine is protective in patients with non-alcoholic fatty liver disease.

BACKGROUND: Non-alcoholic fatty liver disease (NAFLD), the hepatic manifestation of metabolic syndrome, is the most common cause of primary liver disease. Although recent studies have found that coffee drinking is protective against end stage chronic liver disease, there are scarce caffeine intake data in NAFLD specifically. AIM: To investigate the effects of dietary behaviour in NAFLD patients, using four continuous cycles of the National Health and Nutrition Examination Surveys (NHANES 2001-2008). METHODS: Using data from four continuous cycles of NHANES, dietary intake questionnaires that list 62 nutrition components. Logistic regression was used to identify independent predictors of NAFLD among nutrition components after adjustment for potential clinical confounders. All analyses were run using sas 9.1 and SUDAAN 10.0 (SAS Institute Inc., Cary, NC, USA). RESULTS: Of the 62 nutrient components used for the univariate analysis, 38% were significant (P-value <0.05) in NAFLD with caffeine consumption being higher in the control group (P-value <0.001). The multivariate analysis using demographics, clinical parameters and nutritional components found five factors independently associated with NAFLD [African American Race P-value <0.001); Male gender P-value <0.001); Obesity (BMI ≥ 30) P-value <0.001); Caffeine intake (mg) P-value <0.001) and total plain water consumption (g) P-value ≤ 0.02)]. CONCLUSIONS: Our analysis shows that caffeine intake is independently associated with a lower risk for NAFLD suggesting a potential protective effect. These data necessitate further research to elucidate the mechanism by which caffeine can protect against NAFLD.

A cross-sectional examination of growth indicators from Nicaraguan adolescent girls: a comparison of anthropometric data from their Guatemalan counterparts.

BACKGROUND: Few studies have examined growth data from adolescent girls in Latin America and almost none have been conducted in Nicaragua. Thus this study examines growth data from Nicaraguan adolescent girls. AIM: This study describes cross-sectional growth data from a sample of Nicaraguan girls. These data are compared with data from Mexican-US and Guatemalan girls. It is hypothesized that (a) Mexican-US and Guatemalan wealthy ladina girls will show better indicators of nutritional status when compared with the Nicaraguan girls, and (b) the Nicaraguan girls will show similar anthropometric indicators when compared with poor Guatemalan girls. SUBJECTS AND METHODS: Anthropometric and age at menarche data were collected from a sample of 154 adolescent girls ages 10-17 years living in Managua, Nicaragua. RESULTS: The findings revealed that these girls are significantly shorter and lighter than US, Mexican-US and wealthy Guatemalan adolescent girls. These girls are also significantly taller and heavier than their poor Guatemalan counterparts. CONCLUSION: This study reveals that the Nicaraguan girls are undernourished when compared with other Latin American girls living in an improved overall environment. The data also reveal that the Nicaraguan girls have better indicators of nutritional status when compared with a cohort of poor Guatemalan girls.

Alanine scan mutagenesis of the switch I domain of the Caulobacter crescentus CgtA protein reveals critical amino acids required for in vivo function.

The Caulobacter crescentus CgtA protein is a member of the Obg/GTP1 subfamily of monomeric GTP-binding proteins. In vitro, CgtA displays moderate affinity for both GDP and GTP and displays rapid exchange rate constants for either nucleotide, indicating that the guanine nucleotide-binding and exchange properties of CgtA are different from those of the well-characterized Ras-like GTP-binding proteins. The Obg/GTP1 proteins share sequence similarity along the putative effector-binding domain. In this study, we examined the functional consequences of altering amino acid residues within this conserved domain, and identified that T193 was critical for CgtA function. The in vitro binding, exchange and GTP hydrolysis of the T192A, T193A and T192AT193A mutant proteins was examined using fluorescent guanine nucleotide analogues (mant-GDP and mant-GTP). Substitution of either T192 and/or T193 for alanine modestly reduced binding to GDP and significantly reduced the binding affinity for GTP. Furthermore, the T193A mutant protein was more severely impaired for binding GTP than the T192A mutant. The T193A mutation appeared to account solely for the impaired GTP binding of the T192AT193A double mutation. This is the first report that demonstrates that a confirmed defect in guanine nucleotide binding and GTP hydrolysis of an Obg-like protein results in the lack of function in vivo.

Understanding cultural differences when advising mothers about feeding choices.

Cultural teachings and practices greatly influence a mother's feeding decisions. It is important for all health care professionals to understand the cultures within their community and how various beliefs impact infant nutrition. For example, studies have shown the African American and Hispanic mothers are more likely to gain feeding information from family members. There are significant misconceptions being passed down through the generations which can lead to serious nutritional problems, such as overfeeding and the early introduction of cow's milk and food.