Fungal prosthetic valve endocarditis is a rare but devastating disease. To better characterise this syndrome, we retrospectively reviewed 21 cases of fungal prosthetic valve endocarditis seen at Mayo Clinic over the past 40 years. The average patient age was 65 years with a 2 : 1 male predominance. Twelve of 21 cases (57%) occurred within 1 year of prosthetic valve placement. The aortic valve was most commonly affected, and the most common aetiological agent was Candida species, followed by Histoplasma capsulatum. Although 20 of 21 patients (95%) were immunocompetent, they had other risk factors for fungal infection. Patients typically presented with systemic signs and symptoms of infection, and cardiac imaging was abnormal in 68% of cases. Pathological evaluation of valve material was of high yield, with organisms identified in 92% of cases who underwent valve replacement surgery or had an autopsy performed. Prosthetic valve fungal endocarditis was associated with a high morbidity and mortality, with 67% of patients experiencing complications and 57% of patients dying of infection-related disease. Hopefully, with the prompt institution of early medical therapy, surgical intervention and lifelong oral antifungal suppressive therapy, cure rates will continue to improve.

Monitoring changes in pneumococcal carriage is key to understanding vaccination-induced shifts in the ecology of carriage and impact on health. We longitudinally investigated pneumococcal carriage dynamics in infants. Pneumococcal isolates were obtained from nasopharyngeal (NP) swabs collected 2-weekly from 137 infants enrolled from birth through their first year of life. Pneumococci were serotyped by sequetyping, confirmed by Quellung. Pneumococci were isolated from 54% (1809/3331) of infants. Median time to first acquisition was 63 days. Serotype-specific acquisition rates ranged from 0.01 to 0.88 events/child-year and did not differ between PCV13 and non-PCV13 serotypes (0.11 events/child-year [95% CI 0.07–0.18] vs. 0.11 events/child-year [95% CI 0.06–0.18]). There was no difference in carriage duration between individual PCV13 and non-PCV13 serotypes (40.6 days [95% CI 31.9–49.4] vs. 38.6 days [95% CI 35.1–42.1]), however cumulatively the duration of carriage of non-PCV13 serotypes was greater than PCV13 serotypes (141.2 days (95% CI 126.6–155.8) vs. 30.7 days (95% CI 22.3–39.0). Frequently carried PCV13 serotypes included 19F, 9V, 19A and 6A, while non-PCV13 serotypes included 15B/15C, 21, 10A, 16F, 35B, 9N and 15A. Despite high immunization coverage in our setting, PCV13 serotypes remain in circulation in this cohort, comprising 22% of isolates. Individual PCV13 serotypes were acquired, on average, at equivalent rate to non-PCV13 serotypes, and carried for a similar duration, although the most common non-PCV13 serotypes were more frequently acquired than PCV13 serotypes.

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The emergence of extended-spectrum ␤-lactamase (ESBL) and plasmid-mediated AmpC (pAmpC) enzymes in Escherichia coli raises concern regarding accurate laboratory detection and interpretation of susceptibility testing results. Twenty-six cefpodoxime ESBL screen-positive, cefoxitin-resistant E. coli clinical isolates were subjected to clavulanate ESBL confirmatory testing employing disk augmentation, Etest, and the BD Phoenix NMC/ID-132 panel. Phenotypic pAmpC production was assessed by boronic acid disk augmentation. ESBL and pAmpC genes were detected by gene amplification and sequencing. ESBL genes (SHV and/or CTX-M-type genes) were detected in only 7/26 ESBL screen-positive isolates. Of 23 aminophenylboronic acid screen-positive isolates, pAmpC genes were detected in 20 (CMY-2 or FOX-5 genes). High incidences of false-positive ESBL confirmatory results were observed for both clavulanate disk augmentation (9/19) and BD Phoenix (5/19). All were associated with the presence of pAmpC genes with or without TEM-1. Etest performed poorly, as the majority of interpretations were nondeterminable. In addition, false-negative ESBL confirmatory results were observed in isolates possessing concomitant ESBL and pAmpC genes for Etest (four of five), BD Phoenix (three of five), and disk augmentation (one of five). The results indicate poor performance of currently employed ESBL confirmatory methods in the setting of concomitant pAmpC. Some isolates with pAmpC and ESBL genes fell within the susceptible category to extended-spectrum cephalosporins, raising concern over currently employed breakpoints.Ambler class A extended-spectrum ␤-lactamase (ESBL) genes in Escherichia coli are well documented. Possible ESBL production has been reported to occur in up to 9% of European E. coli isolates (15). In addition, chromosomal Ambler class C AmpC genes have been mobilized and are now being disseminated on plasmids, reminiscent of the early dissemination and evolution of ESBLs (11). Increasingly, reports document the detection of plasmid-mediated AmpC resistance (pAmpC) in E. coli (4,6,12). Data from the SENTRY antimicrobial surveillance program for North America show that 19/65 ESBL screen-positive E. coli isolates harbored pAmpC (5).The ESBL hydrolytic spectrum includes the oxyimino-cephalosporins and monobactams but not 7-␣-methoxy-cephalosporins (cephamycins) and is inhibited by clavulanate, sulbactam, and tazobactam. The broader spectrum of the AmpC enzymes includes the cephamycins, and AmpC enzymes are not inhibited by clavulanate, sulbactam, or tazobactam. The Clinical and Laboratory Standards Institute (CLSI) recommends that antimicrobial susceptibility testing include screening for ESBL production in E. coli, employing cefpodoxime, ceftazidime, aztreonam, cefotaxime, or ceftriaxone, followed by phenotypic confirmation with clavulanate (3).ESBL screening results are reviewed to select for those organisms that need phenotypic ESBL confirmation, as recommended by CLSI, and results are issued with the aim of preventing inappropriate u...

Sequence analysis of Pneumocystis jiroveci internal transcribed spacer (ITS) regions has become an important epidemiological tool. The objectives of the present study were to investigate sequence variations in the ITS1-5.8S ribosomal DNA (rDNA)-ITS2 regions; determine the P. jiroveci genotypes present in Cape Town, South Africa; and resolve the lineage evolution of the types by use of the coalescent theory. ITS regions were amplified from samples collected from 19 patients. PCR products were cloned, and four to five clones were sequenced from each specimen. Statistical parsimony was applied for coalescence-based network genotype analysis. The most prevalent type was Eg (14 of 19 patients, 33 of 83 clones), followed by Gg (4 of 19 patients, 7 of 83 clones), Eu (3 of 19 patients, 5 of 83 clones), and Gh (2 of 19 patients, 2 of 83 clones). Four new combinations (Eo, Je, Ge, and No), 11 new ITS1 sequences, and 13 new ITS2 sequences were identified. A new ITS2 type was detected in three patients and was designated type u. Coinfection appeared to be common, with 15 of 19 patients harboring more than one type and with up to six types per specimen. The resultant parsimony network identified Eg as the most probable ancestral haplotype and supported the occurrence of recombinational events within the population studied. Although the 5.8S rDNA region revealed only 13 clones containing one to two nucleotide polymorphisms, it may assist in defining types. Coalescent theory proposed that Eg is an ancestral type from which microevolutionary subtypes radiate.Pneumocystis pneumonia (PCP) is a major contributor to morbidity and mortality in immunocompromised individuals (16,18). Many molecular epidemiological techniques are not applicable for the typing of Pneumocystis, as it cannot readily be propagated in vitro. Regions that have been investigated for use in the design of a typing method include the mitochondrial large-subunit rRNA, mitochondrial small-subunit rRNA, the arom locus, and internal transcribed spacer (ITS) regions (21). The sequence diversity of the Pneumocystis jiroveci ITS1 and ITS2 regions prompted these regions to be the basis on which typing of P. jiroveci could be conducted (10). Ribosomal DNA (rDNA) of P. jiroveci is present as a single copy in the cell and is transcribed as a single transcript, with 18S rRNA, 5.8S rRNA, and 26S rRNA occurring in tandem (4). The rRNA genes are separated by the ITS1 region between 18S rRNA and 5.8S rRNA and the ITS2 region between 5.8S rRNA and 26S rRNA (3, 6). Globally, the most frequently encountered genotypes are Eg and Ne (9, 20, 21). Latouche et al. (8) proposed that as a specific type was seen to persist during the same episode of PCP, genotype switching did not occur. However, in a study conducted with 19 patients during the same episode of PCP, genotype changes were observed in 53% of the patients (5) and coinfection with more than one genotype has been reported in a high proportion of PCP episodes (10,12,14,20,21,22). The present understanding is that P. jiroveci inf...