Increased reports of Mycoplasma pneumoniae from laboratories in Scotland in 2010 and 2011 - impact of the epidemic in infants

In common with reports from other European countries, we describe a substantial increase in the number of laboratory reports of Mycoplasma pneumoniae in Scotland in 2010 and 2011. The highest number of reports came from those aged one year and younger. However, reports from young children were more likely to come from PCR testing than serological testing.

A new multiplex real-time PCR test for HSV1/2 and syphilis: an evaluation of its impact in the laboratory and clinical setting

OBJECTIVES

To develop, evaluate and implement a new multiplex real-time PCR test for the detection of herpes simplex virus (HSV)1, HSV2 and syphilis in a single sample using a single test.

METHODS

A multiplex real-time PCR test detecting HSV1, HSV2 and Treponema pallidum was designed, validated and evaluated for a period of 6 months on patients attending the Sandyford Initiative (a series of genitourinary medicine clinics in and around Glasgow). A total of 692 samples were tested, and T pallidum PCR positives were confirmed by a second PCR at the Scottish Reference Laboratory (SBSTIRL). All PCR results were aligned with dark ground microscopy findings and serological results where available and compared.

RESULTS

The laboratory validation of the multiplex assay showed the test to be sensitive, specific and robust. Of the 692 samples, 139 were positive for HSV1, 136 for HSV2, 15 for syphilis, one for both syphilis and HSV1, and 401 were negative; the reference laboratory confirmed all T pallidum PCR-positive samples. The PCR test was more sensitive than both dark ground microscopy and serological testing for the diagnosis of primary syphilis.

CONCLUSIONS

The introduction of this new test has led to a better turnaround time for the diagnosis of genital ulcer disease, better detection of primary syphilis infection, and the detection of unexpected cases of syphilis where the aetiological agent suspected was HSV.

Using multiplex real time PCR in order to streamline a routine diagnostic service

An increasing number of virology laboratories are now utilising in house real time PCR assays as the frontline diagnostic tests. As the number of tests on offer increases the natural progression from this will be to rationalise their service via multiplexing. Since 2003 we have introduced a large number of qualitative and quantitative multiplex real time PCR assays into our routine testing service. This paper describes the development of the multiplex assays, the problems encountered and the resultant benefits to the routine service.

Contamination with PCR detectable virus in a virus isolation quality assurance panel

External quality control schemes are an essential part of the quality assurance of all diagnostic virology laboratories. There are a few providers of nucleic acid detection quality control panels. Consequently, diagnostic laboratories may test panels that are developed specifically for virus isolation by nucleic acid detection methods. Here, we report on a recent simulated eye swab panel from a National external quality assessment service, which was meant for virus isolation but which we tested by polymerase chain reactions assays. The results suggest that the samples had been contaminated at source leading to difficulty in interpretation of the panel and a poor score.

Comparison of real-time PCR and EIA for the detection of outbreaks of acute gastroenteritis caused by norovirus

We compared real-time polymerase chain reaction (PCR) and a newly developed enzyme immunoassay (EIA) for the detection of noroviruses (NoV) in 70 stool samples taken from outbreaks and sporadic cases of acute gastroenteritis. The real-time PCR classified more samples as positive than the EIA (26 versus 10) and detected more outbreaks of NoV (six versus two). Real-time PCR offers rapid and sensitive diagnosis for both sporadic cases and outbreaks of NoV gastroenteritis and, by comparison, the reduced sensitivity and specificity of the EIA will result in negative samples having to be tested by PCR. This delay might undermine current infection control procedures, lead to further dissemination of infection and increase healthcare costs.

Hepatitis B virus (HBV) and hepatitis C virus (HCV) infections in health care workers (HCWs): guidelines for prevention of transmission of HBV and HCV from HCW to patients

The transmission of viral hepatitis from health care workers (HCW) to patients is of worldwide concern. Since the introduction of serologic testing in the 1970s there have been over 45 reports of hepatitis B virus (HBV) transmission from HCW to patients, which have resulted in more than 400 infected patients. In addition there are six published reports of transmissions of hepatitis C virus (HCV) from HCW to patients resulting in the infection of 14 patients. Additional HCV cases are known of in the US and UK, but unpublished. At present the guidelines for preventing HCW to patient transmission of viral hepatitis vary greatly between countries. It was our aim to reach a Europe-wide consensus on this issue. In order to do this, experts in blood-borne infection, from 16 countries, were questioned on their national protocols. The replies given by participating countries formed the basis of a discussion document. This paper was then discussed at a meeting with each of the participating countries in order to reach a Europe-wide consensus on the identification of infected HCWs, protection of susceptible HCWs, management and treatment options for the infected HCW. The results of that process are discussed and recommendations formed. The guidelines produced aim to reduce the risk of transmission from infected HCWs to patients. The document is designed to complement existing guidelines or form the basis for the development of new guidelines. This guidance is applicable to all HCWs who perform EPP, whether newly appointed or already in post.

First rotavirus, now astrovirus: the evolving benefits of RT-PCR

We compared RT-PCR and a newly developed amplified EIA for the detection of human astrovirus (HAstV) in 48 stool samples taken from children of less than five years of age with gastroenteritis. The RT-PCR classified more samples as positive than the EIA (18 versus 8). Without sensitive diagnosis, infection control policies will be disadvantaged and the true economic burden of HAstV underestimated.

Importance of PCR in the diagnosis and understanding of rotavirus illness in the community

Rotavirus infections pose a significant economic burden due to hospitalisation and missed workdays. Recent studies have shown that RT-PCR may detect more symptomatic cases of rotavirus infection than antigen detection methods. We compared RT-PCR, enzyme immunoassay (EIA) and an immunochromatography method (ICG) applied to 107 stool samples. The RT-PCR detected 58 positive samples whereas the EIA and ICG detected 28 and 29 positive samples respectively. The RT-PCR assay detected all 17 samples found positive by both the EIA and ICG. Without sensitive diagnosis, infection control policies will be disadvantaged and the true economic burden of rotavirus underestimated.