bDespite the growing importance of carbapenem-resistant Klebsiella pneumoniae (CRKP), the clonal relationships between CRKP and antibiotic-susceptible isolates remain unclear. We compared the genetic diversity and clinical features of CRKP, third-generation and/or fourth-generation cephalosporin-resistant (Ceph-R) K. pneumoniae, and susceptible K. pneumoniae isolates causing bloodstream infections at a tertiary care hospital in New York City between January 2012 and July 2013. Drug susceptibilities were determined with the Vitek 2 system. Isolates underwent multilocus sequence typing and PCR sequencing of the wzi and bla KPC genes. Clinical and microbiological data were extracted from patient records and correlated with molecular data. Among 223 patients, we identified 272 isolates. Of these, 194 were susceptible, 30 Ceph-R, and 48 CRKP, belonging to 144 sequence types (STs). Susceptible (127 STs) and Ceph-R (20 STs) isolates were highly diverse. ST258 dominated CRKP strains (12 STs, with 63% ST258). There was minimal overlap in STs between resistance groups. The bla KPC-3 gene (30%) was restricted to ST258/wzi154, whereas bla KPC-2 (70%) was observed for several wzi allele types. CRKP infections occurred more frequently among solid organ transplant (31%) and dialysis (17%) patients. Mortality rates were high overall (28%) and highest among CRKP-infected patients (59%). In multivariable analyses, advanced age, comorbidities, and disease severity were significant predictors of 30-day mortality rates, whereas the K. pneumoniae susceptibility phenotype was not. Among CRKP infections, we observed a borderline significant association of increased mortality rates with ST258 and the wzi154 allele. Although the clonal spread of ST258 continues to contribute substantially to the dissemination of CRKP, non-ST258 strains appear to be evolving. Further investigations into the mechanisms promoting CRKP diversification and the effects of clonal backgrounds on outcomes are warranted. Infections due to carbapenem-resistant Enterobacteriaceae have emerged as an important public health problem over the past decade and are now considered an urgent antibiotic-resistant threat by the Centers for Disease Control and Prevention (CDC), the category of greatest concern (1). In the United States, carbapenem resistance among Enterobacteriaceae is primarily attributable to the production of the Klebsiella pneumoniae carbapenemase (KPC) (2, 3), which is plasmid mediated and most commonly encountered in K. pneumoniae in nosocomial settings (4, 5). Bloodstream infections (BSIs) caused by carbapenem-resistant K. pneumoniae (CRKP) are associated with particularly high mortality rates (6-8), with previous studies reporting hospital mortality rates of 40 to 70%, compared to rates of 20 to 30% among matched patients with bacteremia due to susceptible K. pneumoniae (4, 9).A single clone, multilocus sequence type 258 (ST258), has been found to account for the majority of CRKP infections in the United States and was identified among 70% of isolates s...

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Background Measles and congenital rubella syndrome remain significant causes of morbidity and mortality despite available vaccines. HIV-infected youth may be at increased risk of measles because of greater waning immunity following vaccination. At a population level, they constitute a potentially large pool of susceptibles to measles and rubella. More data among HIV-infected youth in sub-Saharan Africa are needed to guide vaccination policy and control strategies. Methods This cross-sectional study was nested within two ongoing studies of malaria and HIV in Zambia. Dried blood spot cards from youth (5–15 years) in these studies from 2009–2013 were tested for IgG antibodies to measles and rubella viruses. HIV-uninfected youth, HIV-infected treatment-naïve youth, and HIV-infected youth receiving antiretroviral therapy (ART) were compared. Results 617 HIV-uninfected, 144 HIV-infected treatment-naïve, and 128 HIV-infected youth receiving ART were included in the study. The proportion seropositive for measles virus was significantly higher among HIV-uninfected youth (92.5%) compared to HIV-infected treatment-naïve youth (74.1%) and HIV-infected youth receiving ART (71.9%). No differences by age were observed. The proportion seropositive for rubella virus was significantly higher among HIV-uninfected youth (54.7%) compared with HIV-infected treatment-naïve youth (41.7%) and HIV-infected youth receiving ART (49.6%), with increases observed by age for all groups. Conclusions Measles seroprevalence was lower among HIV-infected than uninfected youth, consistent with waning immunity following measles vaccination. HIV-infected youth would likely benefit from revaccination. Half of all youth in rural Zambia were susceptible to rubella and may need targeting for catch-up rubella campaigns when measles-rubella vaccine is introduced.