Severe Staphylococcus lugdunensis keratitis

Cross-sectional study of Staphyloccus lugdunensis prevalence in cats

Staphylococcus lugdunensis is a commensal bacterium in humans and other animals that can cause serious infections. The aim of this research was to estimate the frequency of S. lugdunensis in pet cats and to characterize the S. lugdunensis isolates obtained. The prevalence of S. lugdunensis was 0.77% (4/523) in healthy cats and 1.23% (1/81) in sick cats. The isolates (N = 5), which colonized conjunctival sacs, nares, and the anus, were almost fully phenotypically sensitive to antibiotics, but harbored resistance genes to four chemotherapeutic groups. Their sequence types (STs) included ST2, ST3, ST9, and ST15. There was detected a far lower prevalence of S. lugdunensis in pet cats than is reported in the human population. Nevertheless, the phenotypic and genotypic properties of S. lugdunensis isolates found in the current study were very similar to those described previously in isolates of human origin.

Influence of bacterial burden on meibomian gland dysfunction and ocular surface disease

Purpose

Bacterial burden on the eyelid margin and within meibomian glands was evaluated for influence on specific ocular surface disease (OSD) markers across the meibomian gland dysfunction (MGD) spectrum.

Methods

In this prospective, observational, single-center study, 40 patients were divided into 4 equal groups of 10 that encompassed increasingly worse MGD/OSD categories. All patients answered the standard Ocular Surface Disease Index questionnaire, and underwent tear osmolarity testing (TOT), Schirmer 1, matrix metalloproteinase 9 (MMP-9) testing, meibography, and lissamine green staining. Cultures of eyelid margins and meibomian gland secretions were directly plated on blood, chocolate, and Sabouraud agar; smears were sent for gram and Papinicolau evaluation.

Results

Mean patient age was 55.25±17.22 years; there were 10 males and 30 females. TOT and MMP-9 testing were similar across groups. Culture positivity was 62.5% for right eyes, 70% for left eyes, and was not statistically different across groups (for both eyelid margin and meibomian glands). The majority of cultures were positive for coagulase-negative staphylococcus (CNS).

Conclusion

This study is in concordance with others, citing the predominance of CNS within the biofilm of both “normal” and clinically significant MGD/OSD patients. Our study exemplifies that symptoms of OSD do not necessarily correlate with degree of clinical exam findings, nor culture positivity. These results argue that bacterial burden should be reconsidered as a direct risk factor and treatment target for MGD/OSD patients.

Multicenter Study of the Clinical Presentation of Staphylococcus lugdunensis Bacteremia in Japan

Staphylococcus lugdunensis (SL) is a bacterium with a highly pathogenicity than most other coagulase-negative Staphylococcus spp. (CoNS). In Japan, data on this pathogen are sparse, and the current prevalence of SL bacteremia is unknown. Therefore, we investigated the prevalence of SL in blood culture specimens in a prospective multicenter study across 5 facilities. A total of 3,284 patients had positive blood cultures, and 2,478 patients had bacteremia. Among the patients with bacteremia, 7 patients (0.28%) had SL bacteremia. A total of 281 patients had CoNS bacteremia, with SL accounting for 2.49% of these cases. Of the 7 patients with SL bacteremia, 1 patient (14.3%) had infective endocarditis, and 1 patient (14.3%) died within 30 days. In this study, SL resulted in the development of bacteremia in select patients. Clinicians in Japan should be aware of the prevalence of SL and the complications of SL bacteremia.

Diagnosis of prosthetic joint infections using UMD-Universal Kit and the automated multiplex-PCR Unyvero i60 ITI(®) cartridge system: a pilot study

BACKGROUND

Prosthetic joint infections (PJI) are associated with high morbidity and costs. Various efforts have been made to improve the diagnosis of PJI over the past years, but only few studies have assessed the diagnostic utility of nucleic acid amplification test (NAAT) techniques in this context. Here, we report our experience with a commercial 16S rRNA gene PCR and an automated multiplex-PCR cartridge system in identifying pathogens causing PJI.

MATERIALS AND METHODS

A prospective single-centre study was performed including 54 patients with either septic or aseptic prosthetic joint replacement or surgical revision between February 2012 and April 2013. Conventional cultures of periprosthetic tissue samples were compared with the results of broad-range 16S rRNA gene real-time PCR (UMD-Universal Pathogen DNA Extraction and PCR Analysis, Molzym GmbH, Germany) and the multiplex-PCR Unyvero ITI(®) cartridge system (U-ITI; Curetis AG, Germany). Conventional culture and broad-range 16S rRNA gene real-time PCR were performed on all samples. U-ITI was used in a subgroup of 28 cases including all culture-positive cases. The agreement of the results from the methods was assessed.

RESULTS

Of 54 cases, seven were culture-positive. Broad-range 16S rRNA gene real-time PCR gave 6, U-ITI 3 concordant positive results. Of the 47 culture-negative samples, 46 were also negative by broad-range 16S rRNA gene real-time PCR resulting in a 96 % (52/54) agreement between 16S rRNA gene PCR and culture. Of the 21 culture-negative samples analysed with U-ITI, 20 gave negative results, including the single 16S rRNA gene PCR-positive/culture-negative specimen. The rate of agreement between U-ITI and culture results was 82 % (23/28).

CONCLUSION

This pilot study gave no indication of superiority of the used NAATs over conventional culture methods for the microbiological diagnosis of PJI. Drawbacks are susceptibility to contamination in the case of 16S rRNA gene real-time PCR, labour-intensive DNA extraction and limited pathogen panel in the case of the multiplex cartridge PCR system. More prospective trials are needed to evaluate the diagnostic performance of NAATs and their impact on the clinical management of PJI.