Clinical Usefulness of Klebsiella Pneumoniae Carbapenemase-Producing K. Pneumoniae Genotyping: The Experience of a Single-Center Epidemic.

BACKGROUND: During the last decade, the spread of Klebsiella pneumoniae-carbapenemase-producing Klebsiella pneumoniae (KPC-Kp) has increased dramatically worldwide. In this scenario, growing interest has been addressed to genotyping of KPC-Kp strains, which emerged as an important tool for a better understanding of the epidemiological and clinical characteristics of the outbreaks. METHODS: We performed a retrospective cohort study on patients infected with KPC-Kp during a 28-month outbreak period (January 2010-April 2012) at San Gerardo Hospital (Monza, Italy), investigating KPC-Kp genotypes by means of repetitive element sequence-based polymerase chain reaction (Rep-PCR). RESULTS: We enrolled 97 patients infected with KPC-Kp. Rep-PCR analysis identified 5 distinct clone types, with different distribution over time. During the first 12 months of the outbreak period, only 1 clone was detected (clone A, in 47 patients), while the 4 other clones were identified over the remaining 16 months (clones C, E, and F/L in 23, 24, and 3 patients respectively). Mechanical ventilation was less frequent in patients infected with clones C/E/F/L (OR = 0.14; 95% CI: 0.05-0.37) compared to clone A, and the Charlson comorbidity index (CI) was more likely to have a score >5 in patients infected with clones C/E/F/L (OR = 7.21; 95% CI: 2.24-23.14) compared to clone A.Overall mortality was higher in patients infected with clones C/E/F/L (13/20 patients, 65%) compared to those infected with clone A (7/20, 35%). Mortality in patients infected with clones C/E/F/L remained significantly higher even after adjusting for the potential confounding effect of comorbidities (ie, CI), with a hazard ratio (HR) of 4.65 (95% CI: 1.83-11.89). CONCLUSIONS: Our results suggested a close relationship between strain genotype and clinical outcome.

Microarray technology for yeast identification directly from positive blood cultures. A multicenter Italian experience.

The authors evaluated the performance of the MycArray™ Yeast ID (Myconostica Ltd, UK) assay in the identification of a total of 88 yeast isolates recovered in culture as compared to that obtained through routine methods. The turn-around time for species identification directly from cultures by the MycArray was 6 hours, much quicker than classical methods and all yeasts were correctly identified. In two cases a double identification including Saccharomyces cerevisiae was noted, but it was not confirmed by culture. The results show that MycArray Yeast ID can be a potential tool for rapid detection and identification of Candida species.

Seroepidemiology of EBV and interpretation of the "isolated VCA IgG" pattern.

The presence of VCA IgG in the absence of VCA IgM and EBNA-1 IgG antibodies makes classifying EBV infection more difficult as this serological picture can be seen in the case of past infection with EBNA-1 IgG loss or non-appearance, or acute infections with the early disappearance or delayed onset of VCA IgM. The aim of this study was to assess the prevalence of this pattern in 2,422 outpatients with suspected EBV infection examined in 2005-2006, and to interpret its significance by means of immunoblotting. One hundred and seventy-seven (7.3%) of the patients were VCA IgG-positive, VCA IgM-negative and EBNA-1 IgG-negative, 15 of whom (8.5%) presented with heterophile antibodies. Analysis by age class showed that the prevalence of isolated VCA IgG ranged from 4.5% in the subjects aged 1-10 years to 9% in those aged >60 years. Immunoblotting allowed 18.9% of the cases to be classified as acute and 81.1% as past infections, the latter being observed in about 37% of the patients aged less than 10 years and in 100% of those aged >30 years. Therefore, in our case series, the presence of isolated VCA IgG was associated usually with past infection, particularly among adults. In children aged less than 10 years, it was associated mainly with acute infection but as past infection may be present in about one-third of such children, this possibility should not be overlooked.

Revision of the positive predictive value of IgM anti-Toxoplasma antibodies as an index of recent infection.

The severity of congenital Toxoplasma gondii infection underlines the need for a precise diagnosis of acute infection during pregnancy. The search for specific IgM has been widely used for this purpose, but their possible early disappearance or persistence over time limits their meaning. In order to estimate the positive predictive value of anti-Toxoplasma IgM testing, we made an epidemiological analysis of the presence of anti-Toxoplasma IgG and IgM using ELISA in 4786 subjects attending the Hospital of Legnano in 2004-2005: 1360 seen for a clinical check-up and 3426 pregnant women for serological screening. In relation to IgG avidity, the positive predictive value of IgM was 45.98% (95% CI: 35.51-56.45) as a whole: this increased to 83.87% (95% CI: 70.92-96.82) in the patients with a highly positive test for IgM, but decreased to 9.52% (95% CI: 0.00-22.07) in pregnant women with a weakly positive test for IgM. Our results indicate that a highly positive IgM value in patients can be a good index of recent infection, but its poor predictive value in pregnant women underlines the need for additional tests with a follow-up if necessary.