Accredited official statistics

Quarterly epidemiological commentary: mandatory Gram-negative bacteraemia, MRSA, MSSA and C. difficile infections (data up to January to March 2026)

Updated 9 July 2026

Applies to England

Main points

Escherichia coli (E. coli) bacteraemia

In January to March 2026:

• the all-reported incidence rate of E. coli bacteraemia was 71.9 per 100,000 population
• this was a 0.4% increase compared with the same quarter last year, and 1.5% increase compared to the corresponding in 2019
• most cases were community-onset (80.6%), with the remainder hospital onset (19.4%)

Klebsiella species (spp.) bacteraemia

In January to March 2026:

• the all-reported incidence rate of Klebsiella spp. bacteraemia was 22.8 per 100,000 population
• this was a 4.3% increase in rate compared with the same quarter last year, and a 24.4% increase since the corresponding quarter in 2019
• K. pneumoniae was the most common cause of Klebsiella spp. bacteraemia, accounting for 76.7% of cases

Pseudomonas aeruginosa (P. aeruginosa) bacteraemia

In January to March 2026:

• the all-reported incidence rate of P. aeruginosa bacteraemia was 7.3 per 100,000 population
• this was a 9.9% increase compared with the same quarter last year, and a 5.9% increase compared with the equivalent quarter in 2019
• the rate saw a small but sustained decrease, despite fluctuations since the start of surveillance

Meticillin-resistant Staphylococcus aureus (MRSA) bacteraemia

In January to March 2026:

• the all-reported incidence rate of MRSA bacteraemia was 2.1 per 100,000 population, the highest rate since April 2011 to June 2011
• this was a 17.2% increase compared with the same quarter last year, and a 45.3% increase since the corresponding quarter in 2019
• the proportion of hospital-onset healthcare-associated (HOHA) cases over the last quarter increased from 30.3% to 39.7%, a 9.4% absolute percentage increase; the last time a higher quarterly increase was observed was January 2021 to March 2022 of 10.7%

Meticillin-sensitive Staphylococcus aureus (MSSA) bacteraemia

In January to March 2026:

• the all-reported incidence rate of MSSA bacteraemia was 23.9 per 100,000 population
• there was no substantial change compared with the same quarter last year, and a 16.7% increase since the corresponding quarter in 2019
• overall, cases remain high relative to levels since surveillance began, with increases predominately attributed to community cases

Clostridioides difficile (C. difficile) infection (CDI)

In January to March 2026:

• the all-reported incidence rate of C. difficile infection was 28.1 per 100,000 population
• this was a 4.0% decrease compared with the same quarter last year; there was a 5.6% decrease compared to the peak in 2015, and a 25.1% increase since the corresponding quarter in 2019
• the recent declines across hospital-onset and community-onset rates are a reversal of the previously increasing trend observed between January to March 2024 and January to March 2025

The overnight occupied bed-days for 5 trusts were missing in the source data for 2025 to 2026 FQ4. The trusts affected were:

• The Dudley Group NHS Foundation Trust (trust code: RGP)
• James Paget University Hospitals NHS Foundation Trust (trust code: RNA)
• Birmingham Women’s and Children’s NHS Foundation Trust (trust code: RQ3)
• University Hospitals of Morecambe Bay NHS Foundation Trust (trust code: RTX)
• East and North Hertfordshire Teaching NHS Trust (trust code: RWH)

As a result, these trusts do not contribute to the denominator values used to calculate England-level hospital-onset (HO), hospital-onset healthcare-associated (HOHA) and community-onset healthcare-associated (COHA) incidence rates in this report. Consequently, these incidence rates are likely to be slightly overestimated and any apparent increases should be interpreted with this limitation in mind.

Rolling case counts for all collections

Figure 1 describes the 12-month rolling percentage change in case counts for each data collection, compared to the baseline 12-month period ending in December 2012 for MRSA, MSSA, and E. coli bacteraemia, and ending in December 2017 for Klebsiella spp. and P. aeruginosa.

Figure 1. CDI and bloodstream infections, 12-month rolling percent change December 2012 to March 2026

The 12-month rolling case counts for all 6 organisms have surpassed their respective data collection baselines (Figure 1, Table S7 in the accompanying data tables). Over the whole period, the highest percentage increase in 12-month rolling case counts was observed for MSSA bacteraemia, although the case counts have plateaued in 2026. The start of 2025 saw a flattening of trends in E. coli and Klebsiella spp. bacteraemia, with a recent return to increasing case counts. There has been a sustained decrease in CDI rolling case counts in 2026, reversing the upward trend that began in January 2021. MRSA case counts have shown steep increases from 2022. 

Epidemiological analyses of Gram-negative bacteraemia (E. coli, Klebsiella spp. and P. aeruginosa) data

E. coli bacteraemia

There were 10,390 total reported cases of E. coli bacteraemia in January to March 2026 (Figure 2). The overnight occupied bed days for 5 trusts (trust codes: RGP, RNA, RQ3, RTX and RWH) were missing for 2025 to 2026 FQ4. Therefore, HO, HOHA and COHA incidence rates presented in this report will be slightly overestimated. Any apparent increases in these incidence rates should not be interpreted in isolation and should be considered alongside this data limitation.

Compared to start of surveillance

There was an increase of 24.2% in the incidence rate from 57.9 to 71.9 cases per 100,000 population compared to January to March 2012 (the corresponding quarter in the starting year of surveillance). This increase was primarily due to an increase in community-onset cases. There were 8,372 community-onset cases in January to March 2026 (Table S1 in the accompanying data tables). This corresponded to a 33.5% increase in community-onset incidence rate from 43.4 to 57.9 cases per 100,000 population since January to March 2012. Over the same period, there were 2,018 hospital-onset cases, and the hospital-onset incidence rate increased by 6.5% increase from 21.6 to 23.0 per 100,000 bed-days.

Compared to pre-pandemic

When comparing January to March 2026 with the equivalent pre-COVID-19 pandemic period (January to March 2019), there was a decrease of 2.8% in the incidence rate from 73.9 to 71.9 cases per 100,000 population. The incidence rate of community-onset cases decreased by 4.4% from 60.6 to 57.9 cases per 100,000 population. The hospital-onset incidence rate increased by 8.7% from 21.1 to 23.0 cases per 100,000 bed-days.

Compared to last year

When comparing the most recent quarter to last year’s corresponding quarter, the incidence rate of total reported cases showed a slight increase of 0.4% from 71.6 to 71.9 per 100,000 population. Community-onset cases increased by 1.8% in incidence rate, from 56.9 to 57.9 per 100,000 population. Over the same period, the incidence rate of hospital-onset E. coli bacteraemia cases decreased by 1.3% from 23.3 to 23.0 per 100,000 bed-days.

Figure 2. Quarterly rates of E. coli bacteraemia, total reported, hospital-onset and community-onset cases, July 2011 to March 2026

Seasonality

A strong seasonal trend is visible with total reported E. coli bacteraemia, whereby the highest rates are observed between July to September of each year, although there were more fluctuations during the pandemic years. The same seasonal trend is apparent among hospital-onset rates since July 2011, excluding the period January 2020 to December 2021.

Prior trust exposure

Since April 2020, community-onset E. coli bacteraemia cases have been further categorised into healthcare- or community- associated, based on whether each patient had been previously discharged from the same reporting acute trust in the preceding 28 days (see our quality and methodology information (QMI) report for more details).

Community-onset community-associated (COCA) cases accounted for the majority of reported community-onset E. coli bacteraemia from April 2020. While there have been some fluctuations, the proportion of COCA cases has remained similar at around two-thirds of all cases since. The distribution of cases by these categories has remained broadly stable since 2021. In the current quarter, 65.6% of cases were community-onset community-associated (COCA), 14.9% were community-onset healthcare-associated (COHA), and 19.4% were hospital-onset healthcare-associated (HOHA) (Figure 3, Table S1a in the accompanying data tables).

Figure 3. Percentage of E. coli bacteraemia cases by prior trust exposure, April 2020 to March 2026

Klebsiella spp. bacteraemia

There were 3,302 total reported cases of Klebsiella spp. bacteraemia in January to March 2026 (Figure 4). The overnight occupied bed days for 5 trusts (trust codes: RGP, RNA, RQ3, RTX and RWH) were missing for 2025 to 2026 FQ4. Therefore, HO, HOHA and COHA incidence rates presented in this report will be slightly overestimated. Any apparent increases in these incidence rates should not be interpreted in isolation and should be considered alongside this data limitation.

Compared to start of surveillance

There was an increase of 39.4% in the incidence rate from 16.4 to 22.8 cases per 100,000 population compared to January to March 2018 (the corresponding quarter in the starting year of surveillance). There were 938 hospital-onset cases, a 35.3% increase in hospital-onset incidence from 7.9 to 10.7 per 100,000 bed-days compared to January to March 2018 (Table S2 in the accompanying data tables). There were 2,364 community-onset cases, which corresponded to a 44.9% increase in incidence rate from 11.3 to 16.4 cases per 100,000 population.

Compared to pre-pandemic

When comparing January to March 2026 with the equivalent pre-COVID-19 pandemic period (January to March 2019), there was an increase of 22.4% in the incidence rate from 18.7 to 22.8 cases per 100,000 population. The incidence rate of community-onset cases increased by 23.4% from 13.2 to 16.4 cases per 100,000 population. The hospital-onset incidence rate increased by 24.9% from 8.5 to 10.7 cases per 100,000 bed-days.

Compared to last year

When comparing the most recent quarter to last year’s corresponding quarter, the incidence rate of total reported cases increased by 4.3% from 21.9 to 22.8 per 100,000 population. This recent increase was due to an increase in community-onset cases with an increase of 9.9% in incidence, from 14.9 to 16.4 per 100,000 population. While the hospital-onset incidence rate showed a decrease of 4.2% from 11.1 to 10.7 per 100,000 bed-days.

By species

During January to March 2026, 76.7% of the total reported Klebsiella spp. bacteraemia were K. pneumoniae, 14.3% were K. oxytoca, and 3.9% were K. aerogenes. Whilst the incidence rates of other species of Klebsiella have remained stable or decreased, incidence rates of K. pneumoniae have been rising consistently since surveillance began and are the primary contributor to the recent increases in Klebsiella spp. bacteraemia.

Figure 4. Quarterly rates of Klebsiella spp. bacteraemia, all-reported, hospital-onset and community-onset cases, by species, April 2017 to March 2026

Seasonality

There is a seasonal trend of total reported Klebsiella spp. bacteraemia cases, with higher rates normally observed in July to December and lower rates observed from January to June of each year.

Prior trust exposure

Since the addition of prior trust exposure classifications in April to June 2020, COCA cases have made up slightly more than half of all Klebsiella spp. bacteraemia. The proportion of HOHA cases peaked at 39.6% in January to March 2021; this coincided with the increase in COVID-19 cases and associated hospitalisations observed in January 2021, where an increase in Klebsiella spp. bacteraemia was observed in the hospital setting (Sloot et al. 2022). This proportion has since decreased and was 28.4% in the latest quarter. In the same period, the proportion of COHA cases was 15.5% (Figure 5, Table S2a in the accompanying data tables).

Figure 5. Percentage of Klebsiella spp. bacteraemia cases by prior trust exposure, April 2020 to March 2026

Pseudomonas aeruginosa bacteraemia

There were 1,062 total reported cases of P. aeruginosa bacteraemia in January to March 2026 (Figure 6). The overnight occupied bed days for 5 trusts (trust codes: RGP, RNA, RQ3, RTX and RWH) were missing for 2025 to 2026 FQ4. Therefore, HO, HOHA and COHA incidence rates presented in this report will be slightly overestimated. Any apparent increases in these incidence rates should not be interpreted in isolation and should be considered alongside this data limitation.

Compared to start of surveillance

The incidence rate increased by 5.0% from 7.0 to 7.3 cases per 100,000 population when compared with January to March 2018 (the corresponding quarter in the starting year of surveillance). There were 391 hospital-onset cases, with a slight increase of 0.6% from 4.4 to 4.5 per 100,000 bed-days compared to January to March 2018 (Table S3 in the accompanying data tables). There were 671 community-onset cases, which corresponded to a 12.1% increase in incidence rate from 4.1 to 4.6 cases per 100,000 population.

Compared to pre-pandemic

When comparing January to March 2026 with the equivalent pre-COVID-19 pandemic period (January to March 2019), there was an increase of 5.6% in the incidence rate from 7.0 to 7.3 cases per 100,000 population. The incidence rate of community-onset cases increased by 6.6% from 4.4 to 4.6 cases per 100,000 population. The hospital-onset incidence rate increased by 8.2% from 4.1 to 4.5 cases per 100,000 bed-days.

Compared to last year

When comparing the most recent quarter to last year’s corresponding quarter, the incidence rate of total reported cases increased by 9.9% from 6.7 to 7.3 per 100,000 population.

Figure 6. Quarterly rates of P. aeruginosa bacteraemia, total reported, hospital-onset and community-onset cases, April 2017 to March 2026

Prior trust exposure

Similarly to E. coli and Klebsiella spp., COCA cases make up the highest proportion of P. aeruginosa bacteraemia cases. In the latest quarter, 46.8% of the total belonged to COCA, 16.4% were COHA, and 36.8% were HOHA (Figure 7, Table S3a in the accompanying data tables).

Figure 7. Percentage of P. aeruginosa bacteraemia cases by prior trust exposure, April 2020 to March 2026

Epidemiological analyses of Staphylococcus aureus bacteraemia data

MRSA bacteraemia

There were 300 total reported cases of MRSA bacteraemia in January to March 2026 (Figure 8). Due to the low incidence of MRSA bacteraemia, proportions should be interpreted with caution. The overnight occupied bed days for 5 trusts (trust codes: RGP, RNA, RQ3, RTX and RWH) were missing for 2025 to 2026 FQ4. Therefore, HO, HOHA and COHA incidence rates presented in this report will be slightly overestimated. Any apparent increases in these incidence rates should not be interpreted in isolation and should be considered alongside this data limitation.

Compared to start of surveillance

There has been a considerable decrease in the incidence rate of total reported MRSA bacteraemia since the enhanced mandatory surveillance of MRSA bacteraemia began in April 2007. The incidence rate saw a decrease of 72.4% from 7.5 to 2.1 cases per 100,000 population when compared with January to March 2008 (the corresponding quarter in the starting year of surveillance). A similar trend was observed with the incidence rate of hospital-onset cases (Table S4 in the accompanying data tables). There was a steep decrease of 79.3% from 4.9 to 1.0 case per 100,000 bed-days in April to June 2008 compared to January to March 2014.

Compared to pre-pandemic

When comparing January to March 2026 with the equivalent pre-COVID-19 pandemic period (January to March 2019), there was an increase of 60.8% in the incidence rate from 1.3 to 2.1 cases per 100,000 population, the highest rate since April 2011 to June 2011. The incidence rate of community-onset cases increased by 45.9% from 0.9 to 1.3 cases per 100,000 population. The hospital-onset incidence rate showed an increase of 61.9% from 0.8 to 1.4 per 100,000 bed-days.

Compared to last year

When comparing the most recent quarter to last year’s corresponding quarter, the incidence rate of total reported cases increased by 17.2% from 1.8 to 2.1 per 100,000 population. The incidence rate of community-onset MRSA bacteraemia saw an increase of 2.8%, from 1.2 to 1.3 per 100,000 population. The hospital-onset incidence rate showed an increase of 54.4% from 0.9 to 1.4 per 100,000 bed-days.

Figure 8. Quarterly rates of MRSA bacteraemia, total reported cases (April 2007 to March 2026), hospital-onset and community-onset cases (April 2008 to March 2026)

Prior trust exposure

In the current quarter, 48.3% of cases were community-onset community-associated (COCA), 12.0% were community-onset healthcare-associated (COHA), and 39.7% were hospital-onset healthcare-associated (HOHA) (Figure 9, Table S4a in the accompanying data tables).

Figure 9. Percentage of MRSA bacteraemia cases by prior trust exposure, April 2020 to March 2026

MSSA bacteraemia

There were 3,461 total reported cases of MSSA bacteraemia in January to March 2026 (Figure 10). The overnight occupied bed days for 5 trusts (trust codes: RGP, RNA, RQ3, RTX and RWH) were missing for 2025 to 2026 FQ4. Therefore, HO, HOHA and COHA incidence rates presented in this report will be slightly overestimated. Any apparent increases in these incidence rates should not be interpreted in isolation and should be considered alongside this data limitation.

Compared to start of surveillance

There has been a general trend of increasing incidence of MSSA bacteraemia since mandatory reporting began in 2011, except for a temporary decline in cases during the initial stages of the COVID-19 pandemic. Since January to March 2011 (the corresponding quarter in the starting year of surveillance), there was an increase of 42.6% in incidence rate, from 16.8 to 23.9 per 100,000 population. This increase was primarily due to the increase in community-onset cases. The incidence rate of community-onset cases increased by 51.3% from 11.2 to 16.9 cases per 100,000 population (Table S5 in the accompanying data tables). Over the same period, the incidence rate of hospital-onset cases increased by 38.8% from 8.3 to 11.6 cases per 100,000 bed-days.

Compared to pre-pandemic

When comparing January to March 2026 with the equivalent pre-COVID-19 pandemic period (January to March 2019), there was an increase of 9.6% in the incidence rate from 21.9 to 23.9 cases per 100,000 population. The incidence rate of community-onset cases increased by 7.3% from 15.8 to 16.9 cases per 100,000 population.

Compared to last year

Comparing the most recent quarter (January to March 2026) to the same period in the previous year (January to March 2025), the incidence rate showed no substantial change. The hospital-onset MSSA bacteraemia rate showed an increase of 4.6% in incidence rate from 11.1 to 11.6 per 100,000 bed-days. However, the community-onset MSSA bacteraemia rate remained the same at 16.9 per 100,000 population.

Figure 10. Quarterly rates of MSSA bacteraemia, total reported hospital-onset and community-onset cases, January 2011 to March 2026

Prior trust exposure

In the current quarter, 59.1% of cases were community-onset community-associated (COCA), 11.5% community-onset healthcare-associated (COHA), and 29.4% hospital-onset healthcare-associated (HOHA) (Figure 11, Table S5a in the accompanying data tables).

Figure 11. Percentage of MSSA bacteraemia cases by prior trust exposure, April 2020 to March 2026

Laboratory blood cultures

On a quarterly basis, NHS acute trusts are mandated to report the total number of blood culture sets tested. The median blood culture positivity of E. coli, Klebsiella spp., P. aeruginosa, MRSA and MSSA bacteraemia in trusts in England decreased slightly from 3.4% at the start of the surveillance, in April to June 2017, to 3.1% in the latest quarter of January to March 2026. There were some minor fluctuations in the intervening quarters (Figure 12, Table S9 in the accompanying data tables). The number of trusts submitting quarterly is variable. Overall, 105 trusts submitted data in January to March 2026.

Figure 12. Trends in pooled E. coli, Klebsiella spp., P. aeruginosa, MRSA and MSSA blood culture median positivity, England, by financial year: July to September 2017 to January to March 2026 [note 2]

Note 2: the number of trusts submitting data on blood culture sets has declined in the 2 most recent financial quarters, Q3 2025 and Q4 2025. Data from these quarters, shown with the dashed line on the graph, is incomplete and should be interpreted with caution.

There has been a slight increase in the testing rate in the latest quarter, at 34.9 tests per 1,000 population (Figure 13, Table S8 in the accompanying data tables), compared with 34.3 tests per 1,000 population in the previous quarter (October to December 2025). Changes in the sampling rate do not appear to have substantially impacted positivity, which has remained relatively stable between 2.8% and 3.9% during the surveillance period. However, there may be variation by data collection or at trust-level.

Figure 13. Trends in the rate of blood culture sets, England, by financial year: April to June 2010 to January to March 2026 [note 2]

Note 2: the number of trusts submitting data on blood culture sets has declined in the 2 most recent financial quarters, Q3 2025 and Q4 2025. Data from these quarters, shown with the dashed line on the graph, is incomplete and should be interpreted with caution.

Epidemiological analyses of Clostridioides difficile infection (CDI) data

There were 3,977 total reported cases of CDI in January to March 2026 (Figure 14). The overnight occupied bed days for 5 trusts (trust codes: RGP, RNA, RQ3, RTX and RWH) were missing for 2025 to 2026 FQ4. Therefore, HO, HOHA and COHA incidence rates presented in this report will be slightly overestimated. Any apparent increases in these incidence rates should not be interpreted in isolation and should be considered alongside this data limitation.

Compared to start of surveillance

Since the initiation of CDI surveillance in April 2007, there have been substantial decreases in the incidence of CDI. Compared to January to March 2008 (the corresponding quarter in the starting year of surveillance), the overall incidence rate saw a decrease of 72.8% from 103.3 to 28.1 per 100,000 population. The community-onset incidence rate saw a decrease of 57.0% from 36.7 to 15.8 cases per 100,000 population (Table S6 in the accompanying data tables). The hospital-onset incidence rate saw a decrease of 78.0% from 90.0 to 19.8 cases per 100,000 bed-days.

Compared to pre-pandemic

Comparing the latest quarter with the corresponding pre-pandemic quarter of (January to March 2019), the overall incidence rate saw an increase of 46.2% from 19.2 to 28.1 cases per 100,000 population. The incidence rate of community-onset cases increased by 40.3% from 11.2 to 15.8 cases per 100,000 population. The incidence rate of hospital-onset cases increased by 61.2% from 12.3 to 19.8 cases per 100,000 bed-days.

Compared to last year

Comparing the latest quarter to the same period in the previous year, the incidence rate decreased by 4.0%, from 29.2 to 28.1 cases per 100,000 population. Hospital-onset CDI cases decreased by 8.5% in incidence rate from 21.7 to 19.8 per 100,000 bed-days. The community-onset incidence rate increased by 3.2% from 15.3 to 15.8 per 100,000 population.

Figure 14. Quarterly rates of C. difficile infection, total reported, hospital-onset and community-onset cases, April 2017 to March 2026

Prior trust exposure

The largest proportion of cases in the latest quarter were HOHA, accounting for 43.8% of the total (Figure 15, Table S6a in the accompanying data tables). COCA cases in the latest quarter were 28.6% of the total. COHA and community-onset indeterminate-association (COIA) cases constituted 17.4% and 10.2% in the last quarter, respectively.

Figure 15. Percentage of C. difficile infection cases by prior trust exposure, April 2020 to March 2026

Laboratory stool specimens

On a quarterly basis, NHS acute trusts are mandated to report the total number of stool specimens tested and the total number of stool specimens tested for diagnosis of CDI. There has been a decline in the overall stool sampling rate in the latest quarter at 32.0 tests per 1,000 population in January to March 2026. There has since been a sharp decline in C. difficile diagnosis stool sampling rate in the latest quarter at 11.8 per 100,000 population (Figure 16, Table S8 in the accompanying data tables).

The declines in the rates of overall stool specimen sampling and specimens examined for C. difficile diagnosis are currently under investigation, as the reduction in the number of trusts reporting during this period may have contributed to the observed decrease, particularly if trusts with historically higher rates that usually submit data did not report this quarter. This may in turn have affected the observed increase in CDI positivity rate.

Figure 16. Trends in the rate of stool specimens examined for CDI diagnosis and overall stool specimens examined, England, by financial year: April to June 2010 to January to March 2026 [note 2]

Note 2: the number of trusts submitting data on stool specimen sampling has declined in the 2 most recent financial quarters, Q3 2025 and Q4 2025. Data from these quarters, shown with the dashed line on the graph, is incomplete and should be interpreted with caution.

CDI positivity was initially 3.4% in April to June 2010, before declining to 2.3% by the same quarter in 2012 (Figure 17, Table S9 in the accompanying data tables). Since then, the CDI positivity rate has been predominately stable, with a positivity of 1.9% in the latest quarter of January to March 2026. While the sampling rate has increased concurrently with the increase in CDI incidence, this does not appear to have substantially impacted positivity which has remained between 1.7% to 3.1% during this period. However, there may be variation by data collection or at trust-level.

Figure 17. Trends in median percentage positivity of stool specimens examined for CDI diagnosis, April 2010 to March 2026 [note 2]

Note 2: the number of trusts submitting data on stool specimen sampling has declined in the 2 most recent financial quarters, Q3 2025 and Q4 2025. Data from these quarters, shown with the dashed line on the graph, is incomplete and should be interpreted with caution.

Data sources and methodology

For detailed information about the data sources and methodology used to analyse data in this report, please refer to our QMI report. Some additional information related to this publication is summarised below.

Data sources

Numerator data

Infection episode data used in this report were extracted from UKHSA’s HCAI data capture system (DCS) on 3 June 2026.

Population data

Mid-year resident population estimates are up to calendar year 2024 released by the Office for National Statistics and based on the 2021 census for England are used to derive the population denominator for the total reported incidence rates and the community-onset incidence rates. Calendar year 2024 is then used as a proxy for years 2025 and 2026.

Bed-day data

For bacteraemia and CDI, the average bed-day activity reported by NHS England’s hospital occupancy (KH03) returns is used to derive the bed-day denominator for hospital-onset incidence rates. As of Q1 FY 2010 to 2011, bed-day data has been available on a quarterly basis and has been used as such since Q2 FY 2011 to 2012.

The KH03 data used for this report were published by NHS England on 21 May 2026; this may include revisions of previously published data used in earlier reports.

On 1 December 2015, UKHSA reviewed its policy for processing KH03 data. Data irregularities identified have been flagged with colleagues at NHS England. Until we receive confirmation that any identified change in the occupied overnight bed-days for an acute trust is anomalous, UKHSA now uses the data as published in the KH03 data set. Incidence rates published before December 2015 will differ slightly as a result.

For the KH03 data used to calculate rates included in this report to be consistent over the full-time period, previously amended KH03 data for trust United Lincolnshire Hospitals (trust code: RWD) for FY 2014 to 2015 has been altered to reflect that published in the KH03 data set. This could lead to slight differences in hospital-onset assigned rates when compared with publications prior to 1 December 2015.

Missing data for acute trusts in the KH03 returns will continue to be processed as before, where the KH03 return for the same quarter from the previous year will be used as a proxy. The following acute trusts were therefore affected:

• Moorfields Eye Hospital NHS Foundation Trust (RP6) FY 2007 to 2008, and FY 2008 to 2009 KH03 figures: replaced with FY 2006 to 2007 KH03 figure
• Rotherham NHS Foundation Trust (RFR): FY 2009 to 2010 and from April to June 2010, to April to June 2011 KH03 figures: replaced with FY 2008 to 2009 KH03 figure
• Sheffield Teaching Hospitals NHS Foundation Trust (RHQ) from April to June 2010, to April to June 2011 KH03 figures: replaced with FY 2009 to 2010 KH03 data
• The Princess Alexandra Hospital NHS Trust (RQW) April to June 2014, and October to December 2014 KH03 figures: replaced with April to June 2013, to October to December 2013 KH03 figures, respectively
• Ipswich Hospital NHS Trust (RGQ) January to March 2016 KH03 figure: replaced with January to March 2015 figures
• West Suffolk NHS Foundation Trust (RGR) April to June 2016, to October to December 2016 and April to June 2017 KH03 figures: replaced with April to June 2015, to October to December 2015 KH03 figures
• Gloucestershire Hospitals NHS Foundation Trust (RTE) October to December 2016, to January to March 2017 KH03 figures: replaced with October to December 2015, to January to March 2016 KH03 figures

Five trusts (trust codes: RGP, RNA, RQ3, RTX and RWH) had missing overnight occupied bed-day data for 2025 to 2026 FQ4 in the bed availability and occupancy source data from NHS England. Therefore, they did not contribute to England-level HO, HOHA nor COHA denominators. This will have led to slightly underestimated denominators and slightly overestimated HO, HOHA and COHA rates, respectively. Future reports will impute missing source data using their same quarter from the previous year.

COVID-19 and these data

Marked differences in general trends of all the data collections were observed over the course of the SARS-CoV-2 (COVID-19) pandemic. In general, we observed a reduction in the number of counts, compared with what would have been expected, across all bloodstream infection and CDI cases in the initial stages, followed by various fluctuations.

Analysis of voluntary laboratory surveillance data from April 2020 to March 2022 mirrored the changes seen in the mandatory surveillance system during this period, albeit to different extents. Due to the similarities in trends across both systems, these changes do not appear to be a specific ascertainment problem in the mandatory programme.

Hospital activity changed radically over the course of the pandemic, with an influx of patients critically ill with respiratory infection, and cancellation or delays applied to elective procedures. A gradual staged return to normal activity occurred later. Various other general restrictions on movement and mixing were introduced nationally to limit the spread of the virus. We note that post pandemic, many of these collections have now returned to normal pre-pandemic levels, except for E. coli and CDI.

As a result, data and trends from the beginning of the pandemic onwards should be interpreted with caution and take into consideration these otherwise unprecedented changes.

Background information

UK Health Security Agency and this report

Since the UK Health Security Agency (UKHSA) was created in April 2021, it has been responsible for protecting every member of every community from the effect of infectious diseases, chemical, biological, radiological, and nuclear incidents, and other health threats. We provide intellectual, scientific, and operational leadership at national and local level, as well as on the global stage, to make the nation’s health secure.

The agency replaces Public Health England (PHE) and is an executive agency of the Department of Health and Social Care (DHSC). The transition to UKHSA included the integration of both staff and systems. Accordingly, the systems and processes responsible for the publication of the previous annual epidemiological commentaries were incorporated into UKHSA. The same methods of data capture, analysis and dissemination have been employed in the production of this report.

Report summary

This document contains quarterly, national-level epidemiological commentaries for meticillin-resistant Staphylococcus aureus (MRSA), meticillin-susceptible Staphylococcus aureus (MSSA), Escherichia coli (E. coli), Klebsiella spp. and Pseudomonas aeruginosa (P. aeruginosa) bacteraemia and Clostridioides difficile infection (CDI). These include analyses on counts and incidence rates of total reported, hospital-onset (previously referred to as trust-apportioned) and community-onset (previously referred to as non-trust-apportioned) cases of MRSA, MSSA, E. coli, Klebsiella spp. and P. aeruginosa bacteraemia and CDI. All data tables associated with this report are included in an OpenDocument spreadsheet. Data revisions are covered by a data-specific revisions and correction policy.

If this data is used for publication elsewhere, citation to UKHSA, healthcare-associated infections (HCAI) and antimicrobial resistance (AMR) division is required, using the content below.

Further information and contact details

This publication forms part of the range of accredited Official Statistics outputs routinely published by UKHSA which include monthly and annual reports on the mandatory surveillance of MRSA, MSSA and E. coli, Klebsiella spp. and P. aeruginosa bacteraemia and CDI.

Annual report output

Further epidemiological analyses by financial year can be found in UKHSA’s annual epidemiological commentary.

Monthly report outputs

The following reports are produced by UKHSA monthly.

• Gram-negative, MRSA and MSSA bacteraemia, and CDI – monthly data trends
• E. coli, Klebsiella spp., P. aeruginosa, MRSA and MSSA bacteraemia – counts of total reported, hospital-onset healthcare-associated, community-onset healthcare-associated, community-onset community-associated for each bacteraemia by organisation
• CDI – counts of total reported, hospital-onset healthcare-associated, community-onset healthcare-associated, community-onset of indeterminate association, community-onset community-associated CDI by organisation.

Feedback and contact information

For any enquiries or feedback on this report, or to request copies of this report in PDF format, please contact mandatory.surveillance@ukhsa.gov.uk

Accredited official statistics

Our statistical practice is regulated by the Office for Statistics Regulation (OSR). OSR sets the standards of trustworthiness, quality and value in the Code of Practice for Statistics that all producers of Official Statistics should adhere to. You are welcome to contact us directly by emailing mandatory.surveillance@ukhsa.gov.uk with any comments about how we meet these standards. Alternatively, you can contact OSR by emailing regulation@statistics.gov.uk or via the OSR website.

UKHSA is committed to ensuring that these statistics comply with the Code of Practice for Statistics. This means users can have confidence in the people who produce UKHSA statistics because our statistics are robust, reliable and accurate. Our statistics are regularly reviewed to ensure they support the needs of society for information.

Citation

Please cite this document as follows: UK Health Security Agency. Quarterly epidemiology commentary: mandatory MRSA, MSSA and Gram-negative bacteraemia and C. difficile infection in England (up to January to March 2026). London: UK Health Security Agency, July 2026.

Reference

Sloot R, Nsonwu O, Chudasama D, and others. ‘Rising Rates of Hospital-Onset Klebsiella Spp. And Pseudomonas Aeruginosa Bacteraemia in NHS Acute Trusts in England: A Review of National Surveillance Data, August 2020 to February 2021’ Journal of Hospital Infection 2022: volume 119, pages 175 to 181