Hospital-acquired infections (HAI) increase morbidity and mortality and constitute a high financial burden on health care systems. An effective weapon against HAI is early detection of potential outbreaks and sources of contamination. Such monitoring requires microbial typing with sufficient reproducibility and discriminatory power. Here, a microbial-typing method is presented, based on Raman spectroscopy. This technique provides strain-specific optical fingerprints in a few minutes instead of several hours to days, as is the case with genotyping methods. Although the method is generally applicable, we used 118 Staphylococcus aureus isolates to illustrate that the discriminatory power matches that of established genotyping techniques (numerical index of diversity [D] ‫؍‬ 0.989) and that concordance with the gold standard (pulsed-field gel electrophoresis) is high (95%). The Raman clustering of isolates was reproducible to the strain level for five independent cultures, despite the various culture times from 18 h to 24 h. Furthermore, this technique was able to classify stored (؊80°C) and recent isolates of a methicillin-resistant Staphylococcus aureus-colonized individual during surveillance studies and did so days earlier than established genotyping techniques did. Its high throughput and ease of use make it suitable for use in routine diagnostic laboratory settings. This will set the stage for continuous, automated, real-time epidemiological monitoring of bacterial infections in a hospital, which can then be followed by timely corrective action by infection prevention teams.Hospital-acquired infections (HAI) are among the most pressing problems in modern health care. Up to 10% of all admitted patients become infected while hospitalized, with incidences of 30% being reported in intensive-care units (8, 23). These infections cause significant increases in morbidity and mortality and also have considerable impact on the costs of health care (4,5,16,21). Direct medical costs per patient of between $27,000 and $35,000 have been reported (5).Up to 30% of HAI are caused by transmission and can therefore be prevented by means of infection control strategies (6). Several studies have emphasized the importance of active screening of patients in order to identify transmission of microorganisms. This detects possible cases of cross-transmission and thereby indicates the infection control measures to be taken, including isolation of patients (1, 2). Rapid assessment of microbial clonal relationships (typing) enables tracking of the spread of pathogens, which may be used to significantly decrease the number of HAI and additional costs, even in high-risk situations (14,17).Methicillin-resistant Staphylococcus aureus (MRSA) is a leading cause of HAI, and numerous DNA-based typing methods have been developed for the organism. Therefore, we used MRSA as an example to demonstrate the capabilities of a new typing method.Pulsed-field gel electrophoresis (PFGE) is generally the most preferred typing method (9), followed by multiloc...

Abstract. Data of Staphylococcus aureus carriage in Indonesian hospitals are scarce. Therefore, the epidemiology of S. aureus among surgery patients in three academic hospitals in Indonesia was studied. In total, 366 of 1,502 (24.4%) patients carried S. aureus. The methicillin-resistant S. aureus (MRSA) carriage rate was 4.3%, whereas 1.5% of the patients carried Panton-Valentine leukocidin (PVL)-positive methicillin-sensitive S. aureus (MSSA). Semarang and Malang city (odds ratio [OR] 9.4 and OR 9.0), being male (OR 2.4), hospitalization for more than 5 days (OR 11.708), and antibiotic therapy during hospitalization (OR 2.6) were independent determinants for MRSA carriage, whereas prior hospitalization (OR 2.5) was the only one risk factor for PVL-positive MSSA carriage. Typing of MRSA strains by Raman spectroscopy showed three large clusters assigned type 21, 24, and 38, all corresponding to ST239-MRSA-SCCmec type III. In conclusion, MRSA and PVL-positive MSSA are present among patients in surgical wards in Indonesian academic hospitals.

Enterobacteriaceae are important pathogens of both nosocomial and community-acquired infections. In particular, strains with broad-spectrum beta-lactamases increasingly cause problems in health care settings. Rapid and reliable typing systems are key tools to identify transmission, so that targeted infection control measures can be taken. In this study, we evaluated the performance of Raman spectroscopic analysis (RA) for the typing of multiresistant Escherichia coli and Klebsiella pneumoniae isolates using the SpectraCell RA bacterial strain analyzer (River Diagnostics). Analysis of 96 unrelated isolates revealed that RA generated highly reproducible spectra and exhibited a discriminatory power that is comparable to pulsed-field gel electrophoresis. Furthermore, adequate results were obtained for three collections of clinical isolates. RA was able to discriminate outbreak-related isolates from isolates that were not involved in an outbreak or transmission. Furthermore, it was found that the RA approach recognized clones, irrespective of the extended-spectrum ␤-lactamase type. It can be concluded that RA is a suitable typing technique for E. coli and K. pneumoniae isolates. Combining high reproducibility, speed, and ease-of-use, this technique may play an important role in monitoring the epidemiology of these important nosocomial species.

This study explored the potential of Raman spectroscopy for the analysis of poly(3-hydroxybutyrate) (PHB) in bacteria. PHB can be formed in large amounts by certain bacteria as a storage material and is of high importance for industrial biodegradable plastic production. Raman spectra were collected from Cupriavidus necator DSM 428 (H16), from its non-PHB-producing mutant strain C. necator DSM 541, and from pure PHB, in order to determine at which Raman shifts a contribution of PHB in bacterial spectra can be expected. The Raman band intensity at ca. 1734 cm-1 appeared to be suitable for the monitoring of PHB production and consumption. These intensities were linearly related to the PHB concentration (mg L-1 culture) determined by parallel HPLC analysis. Therefore, Raman spectroscopy is considered as a fast and noninvasive technique for the determination and monitoring of the PHB content in bacteria.