Research and analysis

HPR volume 12 issue 34: news (21 September)

Updated 21 December 2018

Mandatory HCAI reports quarterly trends: April to June 2018

Public Health England’s latest quarterly epidemiological commentary on trends in reports of Staphylococcus aureus (MRSA and MSSA) and Gram-negative bacteraemia, and of Clostridium difficile infections, mandatorily reported by NHS acute Trusts in England up to April to June 2018, has been published on the GOV.UK website [1].

The report, including tabular and graphical information, provides data for the April to June 2018 quarter (updating the previous report published in June 2018). Some important facts are listed below.

MRSA bacteraemia

There was a steep decline of 85% in the incidence rate of all reported MRSA cases between April to June 2007 and January to March 2014 (from 10.2 per 100,000 population to 1.5). The rate remained broadly stable at around 1.5 to 1.7 cases per 100,000 population between January to March 2014 and April to June 2018.

There was a steep decrease (79%) in the incidence rate of hospital-onset cases – from 4.9 cases per 100,000 bed-days to 1.0 – between April to June 2008 and January to March 2014. Between January to March 2014 and April to June 2018, the rate of hospital-onset MRSA bacteraemia has fluctuated but remained broadly stable. The incidence rate for April to June 2018 is 15% lower than the incidence rate in January to March 2014.

When comparing the most recent quarter with the same period last year (April to June 2017 and April to June 2018), the incidence rate of hospital-onset MRSA bacteraemia decreased by 8% from 0.93 to 0.86 cases per 100,000 bed-days; incidence rates of community-onset cases also decreased by 8% – from 1.6 to 1.5 cases per 100,000 population – over the same period.

MSSA bacteraemia

Since the mandatory reporting of MSSA bacteraemia began in January 2011, there has been a general trend of increasing counts and incidence rates. All reported cases of MSSA bacteraemia increased by 36% from 2,199 to 2,992 between January to March 2011 and April to June 2018. This was accompanied by a 32% increase in incidence rate (per 100,000 population) from 16.8 to 21.8.

These increases are primarily driven by the increase in community-onset cases. Over the same period (January 2011 to June 2018), counts and incidence rates of community-onset cases increased by 48% and 41%, respectively, from 1,464 to 2,172 cases, and 11.2 to 15.8 cases per 100,000 population. Over the same period, both counts and incidence rates of hospital-onset cases increased by 12% (735 to 820 cases) and 14% (8.4 to 9.5 cases per 100,000 bed-days).

When comparing the most recent quarter with the same period last year (April to June 2017 and April to June 2018), the incidence rate of hospital-onset MSSA bacteraemia increased by 1% (from 9.46 to 9.53 cases per 100,000 bed-days) compared to a <1% decrease in incidence rates of community-onset cases – from 16.9 to 15.8 cases per 100,000 population – over the same period.

Escherichia coli bacteraemia

Between July to September 2011 and April to June 2018, incidence rates of all reported cases of E. coli bacteraemia increased by 26% from 61.8 to 77.9 cases per 100,000 population (total cases recorded: 8,275-10,700). Similarly, over the same period, incidence rates of community-onset cases increased by 36% from 46.9 to 63.9 (total cases recorded: 6,279-8,785).

Unlike community-onset cases, the count of hospital cases decreased between July to September 2011 and April to June 2018. In July to September 2011, a total of 1,996 cases were reported. In contrast, in April to June 2018 a total of 1,915 cases were reported, a decrease of 6% in the hospital-onset incidence rate – from 23.7 to 22.3 per 100,000 bed-days.

Between April to June 2017 and April to June 2018, there was a 5% increase in both counts and incidence rate of all reported cases from 10,197 to 10,700 cases, and from 74.2 to 77.9 cases per 100,000 population, respectively. Over the same period the counts and the incidence rate of community-onset cases increased by 7% from 8,223 to 8,785 cases, and from 59.8 to 63.9 cases per 100,000 population, respectively.

In contrast, the counts and the incidence rate of hospital-onset cases decreased by 3% between April to June 2017 and April to June 2018, from 1,974 to 1,915 cases, and from 22.9 to 22.3 cases per 100,000 bed-days, respectively.

Klebsiella spp. bacteraemia

Between April to June 2017 and April to June 2018 there was an 8% increase in both counts and incidence rate of all reported Klebsiella spp. cases: from 2,334 to 2,520, and from 17.0 to 18.3 cases per 100,000 population, respectively. Also both counts and the incidence rate of community-onset cases decreased by 7% from 1,670 to 1,788 cases, and from 12.2 to 13.0 cases per 100,000 population, respectively.

Over the same period, the counts and the incidence rate of hospital-onset cases increased by 10% from 664 to 732 cases, and from 7.7 to 8.5 cases per 100,000 bed-days, respectively.

During April to June 2018, 74% (1,861/2,520) of all reported Klebsiella spp. bacteraemia were caused by K. pneumoniae (an increase from 60% in the same quarter in the previous year) compared to 17% (440/2,520) caused by K. oxytoca, the same proportion as the same quarter in the previous year. These proportions were similar among hospital-onset Klebsiella spp. bacteraemia.

Pseudomonas aeruginosa bacteraemia

Between and April to June 2017 and April to June 2018, there was a 4% decrease in both counts and incidence rate of all reported cases of P. aeruginosa from 1,009 to 969, and from 7.3 to 7.1 reports per 100,000 population, respectively. Over the same period, both counts and the incidence rate of community-onset cases decreased by 3% from 636 to 618 cases, and from 4.6 to 4.5 reports per 100,000 population, respectively. Over the same period, the counts and the incidence rate of hospital-onset cases decreased by 6% from 373 to 351 cases, and from 4.3 to 4.1 reports per 100,000 bed-days, respectively.

Clostridium difficile infection

Since the initiation of CDI surveillance in April 2007, there has been an overall decrease in counts and associated incidence rate of both all reported and hospital-onset cases of Clostridium difficile infection (CDI). Seasonal peaks are present in January to March quarters prior to 2014 to 2015, and the July to September quarters between 2014 to 2015 and 2016 to 2017.

The majority of the decrease in the incidence rate occurred between April to June 2007 and January to March 2012 with a 78% decrease in total (all reported) cases of CDI from 16,864 to 3,711 cases, and an associated 79% reduction in incidence rate (per 100,000 population) from 131.6 to 27.9. Subsequently, between January to March 2012 and April to June 2018, the count of all reported cases reduced by 13% from 3,711 to 3,224 cases, and incidence rate reduced by 16% from 27.9 and 23.5.

There were similar but greater reductions among hospital-onset CDI cases; an 85% reduction in cases from 10,436 to 1,613 – and an 84% reduction in incidence rate (per 100,000 bed-days) – from 112.5 to 18.2 – between April to June 2007 and January to March 2012. This was followed by a further 33% decrease in the count – from 1,613 to 1,082 cases – and a decrease of 31% in the incidence rate – from 18.2 to 12.6 cases per 100,000 bed-days – between January to March 2012 and April to June 2018.

When the most recent quarter is compared with the same quarter last year (April to June 2017 and April to June 2018) both counts and incidence rate of all reported CDI decreased by 2% – from 3,304 to 3,224 cases, and 24.0 to 23.5 cases per 100,000 population, respectively. Over the same period, both counts and incidence rate (per 100,000 bed-days) of hospital-onset CDI cases decreased by 4% from 1,130 to 1,082 cases and 13.1 to 12.6, respectively.

Reference

1. PHE (14 June 2018). Quarterly epidemiological commentary: mandatory MRSA, MSSA, Gram-negative bacteraemia, and C. difficile infection data (up to April to June 2018).

Infection reports in this issue of HPR

• Voluntary surveillance of candidaemia in England, Wales and Northern Ireland: 2017

The annual report for bloodstream infections caused by Candida spp., published in this issue of HPR, shows that the overall rate of candidaemia in England, Wales and Northern Ireland in 2017 was 3.6 per 100,000 population, the same rate as in 2016. In 2017, the three most frequently identified Candida species from blood were C. albicans (42%), C. glabrata (24%) and C. parapsilosis (10%). Resistance of C. albicans blood isolates to commonly tested antifungals ranged from <1% for amphotericin B and fluconcazole to 8% for flucytosine. The report also presents analysis of candidaemia rates by geographic region, age and sex. The report is based on analysis of data from Wales and Northern Ireland alongside data for England extracted from PHE’s voluntary surveillance database as of May 2018.