Usefulness of McRAPD for typing and importance of biofilm production in a case of nosocomial ventriculoperitoneal shunt infection caused by Candida lusitaniae

Smoothie Drinks: Possible Source of Resistant and Biofilm-Forming Microorganisms

Smoothie drinks are currently very popular drinks sold especially in fast food establishments. However, smoothies are a significant source of microorganisms. The aim of this study was to evaluate the microbiological quality of smoothies purchased in Eastern Bohemia. A higher prevalence of mesophilic aerobic bacteria (5.4-7.2 log CFU/mL), yeast (4.4-5.9 log CFU/mL) and coliform bacteria (3.1-6.0 log CFU/mL) was observed in vegetable smoothies, in which even the occurrence of enterococci (1.6-3.3 log CFU/mL) was observed. However, the occurrence of S. aureus, Salmonella spp. and Listeria spp. was not observed in any samples. Nevertheless, antimicrobial resistance was observed in 71.8% of the isolated strains. The highest level of resistance was found in isolates from smoothie drinks with predominantly vegetable contents (green smoothie drinks). Considerable resistance was observed in Gram-negative rods, especially to amoxicillin (82.2%) and amoxicillin with clavulanic acid (55.6%). Among enterococci, only one vancomycin-resistant strain was detected. The vast majority of isolated strains were able to form biofilms at a significant level, which increases the clinical importance of these microorganisms. The highest biofilm production was found in Pseudomonas aeruginosa, Kocuria kristinae and Klebsiella pneumoniae. Overall, significant biofilm production was also noted among isolates of Candida spp.

McRAPD unlike MALDI-TOF MS is a suitable candidate for routine discrimination of new Haemophilus influenzae strain acquisition in chronic obstructive pulmonary disease (COPD) and cystic fibrosis

BACKGROUND AND AIMS

Haemophilus influenzae new strain acquisition has been demonstrated to increase the relative risk of acute exacerbation fourfold in contrast to colonisation or chronic infection by the same strain in chronic obstructive pulmonary disease (COPD). Unfortunately, molecular typing techniques are not suitable for routine use due to cost, labour-intensity and need for special expertise. We tested two techniques potentially useful for routine typing, namely the newly available MALDI-TOF MS and the modified McRAPD compared to MLST as the gold standard.

METHODS

In 10 patients (10.8%) suffering from COPD or cystic fibrosis, H. influenzae isolates were recovered repeatedly at different timepoints from the same patient during the study period. This allowed for thirteen pairwise comparisons of typing results in isolates recovered consecutively from the same patient to test the ability of the techniques to uncover new strain acquisition.

RESULTS

MLST detected 9 cases of new strain acquisition among the 13 pairwise comparisons. However, MALDI-TOF MS reported all 13 pairs as different and thus new. In contrast, McRAPD was able to differentiate all the new strain acquisitions from pre-existing ones, both by visual inspection of melting profiles and by Relative Significant Difference values.

CONCLUSIONS

Unlike MALDI-TOF MS, McRAPD appears to be a suitable candidate for routine discrimination of new strain acquisitions because of its accuracy and, rapid, easy and economic performance.

Candida identification: a journey from conventional to molecular methods in medical mycology

The incidence of Candida infections have increased substantially in recent years due to aggressive use of immunosuppressants among patients. Use of broad-spectrum antibiotics and intravascular catheters in the intensive care unit have also attributed with high risks of candidiasis among immunocompromised patients. Among Candida species, C. albicans accounts for the majority of superficial and systemic infections, usually associated with high morbidity and mortality often caused due to increase in antimicrobial resistance and restricted number of antifungal drugs. Therefore, early detection of candidemia and correct identification of Candida species are indispensable pre-requisites for appropriate therapeutic intervention. Since blood culture based methods lack sensitivity, and species-specific identification by conventional method is time-consuming and often leads to misdiagnosis within closely related species, hence, molecular methods may provide alternative for accurate and rapid identification of Candida species. Although, several molecular approaches have been developed for accurate identification of Candida species but the internal transcribed spacer 1 and 2 (ITS1 and ITS2) regions of the rRNA gene are being used extensively in a variety of formats. Of note, ITS sequencing and PCR-RFLP analysis of ITS region seems to be promising as a rapid, easy, and cost-effective method for identification of Candida species. Here, we review a number of existing techniques ranging from conventional to molecular approaches currently in use for the identification of Candida species. Further, advantages and limitations of these methods are also discussed with respect to their discriminatory power, reproducibility, and ease of performance.

Usefulness of PCR-HRMA in identification of non-fermentative Gram-negative rods recovered from patients suffering from cystic fibrosis or chronic obstructive pulmonary disease

Adequate treatment of microbial infections requires rapid and accurate identification of the etiological agent. In routine diagnostics, identification of bacteria conventionally relies on phenotypic testing, which can be hindered by phenotypic variations. Therefore, genotyping techniques should perform faster and more accurately. Recently, the technique of high-resolution melting analysis (HRMA) of PCR amplicons promises to provide a convenient and economic tool of genotypic identification. In our study, we performed prospective routine testing of a PCR-HRMA system that was recently published in a proof-of-the-principle study. The system was evaluated by analysing 275 clinical isolates of bacteria acquired from 65 patients suffering from cystic fibrosis or chronic obstructive pulmonary disease. Our results show that its routine use may result in partial worsening of its discriminatory power; however, it still outmatched conventional phenotyping in the group of non-fermentative Gram-negative rods. Moreover, when supplemented by rapid, simple and economic oxidase test, it can be even simplified for more economic performance.

Fungal infection of a ventriculoperitoneal shunt: histoplasmosis diagnosis and treatment

BACKGROUND

Histoplasmosis is a fungal disease caused by Histoplasma capsulatum, commonly found in the Americas, and Histoplasma duboisii, located in Africa. In the United States, H. capsulatum is prevalent in the Ohio and Mississippi river valleys. In rare circumstances, central nervous system (CNS) histoplasmosis infection can be caused by shunt placement. We present a case report of a 45-year-old woman in whom CNS histoplasmosis developed after having a ventriculoperitoneal (VP) shunt placed for communicating hydrocephalus. A review of the literature on fungal infections after CNS shunt placement as well as treatment options for this subset of patients was undertaken.

METHODS

The PubMed database current to 1958 was filtered and limited to English-language articles. Fifty-eight articles were selected for review based on evidence of information regarding the fungal organism responsible for shunt infection, symptoms, treatment, and/or outcomes. Also included in this review is our case study.

RESULTS

A thorough analysis of the PubMed database revealed 58 reported cases of CNS shunt-related fungal infections in the English-language medical literature as well as 7 therapeutic agents used to treat patients in whom postshunt fungal infections developed.

CONCLUSIONS

We describe the steps in diagnosis of histoplasmosis after shunt placement, provide an effective therapeutic regimen, and review the present understanding of CNS fungal infections. The medical literature was surveyed to compare and analyze various CNS fungal infections that can arise from shunt placement as well as treatments rendered.