Hospital Legionellosis

C. Marena M.D. Ph.D.

Medical Direction

San Matteo Hospital, Pavia, Italy

PROSPECTIVE 14-YEAR SURVEILLANCE

FOR NOSOCOMIAL AND ENVIRONMENTAL

LEGIONELLA PNEUMOPHYLA IMPLICATIONS

AT AN ITALIAN TEACHING HOSPITAL

Background

• Complexity of modern healthcare facilities

• Increasing proportion of immunologically vulnerable pts

• Prevention of healthcare-associated waterborne infections

is a high priority

Hospital Legionellosis

How legionella multiplies

• Large and complex water system

• Favourable pH & temperature 20 – 45C

• Ideal is 37C (human body)

• Low flow and stagnation provides time for

multiplication

• Key nutrients are free iron & L cysteine

• Biofilm protection

Hospital Legionellosis: Risk factors

Hospital Legionellosis in US

FIGURE I. Selected notifiable disease reports, United States, comparison of

provisional 4-week totals August 16, 2014, with historical data

Hospital Legionellosis in Italy

• Legionellosis in Italy is an uncommon disease (16

cases per million inhabitants)

• In 20-32% nosocomial transmission is recognised.

• The number of cases increased from 192 in 2000 to

1,235 cases in 2010.

• A geographical north (highest) / south (lowest)

gradient is present

Hospital Legionellosis in Italy

In Italy 60% of private hospital and 93% of public hospital

are positive for Legionella spp (Napoli et al. 2010 BMC Public Health)

Hospital Legionellosis in Italy

San Matteo Hospital

San Matteo Hospital was opened in 1449, as an institution for the

reception and cure of impoverished sick people, free of charge.

Hospital Setting

The Hospital consists of 28 historic structures, built between 1930 and 2013.

The Hospital extends over 200,000 m2 and the underground galleries contain

4,5 km of water line systems.

Hospital Setting

A new buiding was opened in December 2013. It contains 300 beds including :

emergency DPT, medicine,surgery, ICU, NICU, neurosurgery, obstetrics etc.

• San Matteo Hospital has 1000 beds licenced for

acute care affiliated with the University of Pavia.

• It provides a broad range of care with specialized

centers for organ transplant (heart, lung, kidney,

bone-marrow), cardiovascular care, pediatrics,

infectious diseases, respiratory disease, oncology

etc.

• San Matteo Hospital has 40 ICU beds including 10

beds of NICU

• It has a high-volume of admissions per year (60.000)

and surgical procedures (30.000/year), with a total of

26 operating rooms.

Hospital Setting

Methods

• Since 2000, in response to the publication of national and

regional guidelines, a programme to assess legionella

contamination in the hospital water system was introduced.

• We developed a protocol as a guide for selecting sample sites

at the beginning of a legionellosis investigation. Our selection of

sites was based on past laboratory experience and the

presence of patients at high risk (ICU, transplant unit,

haemathology etc.)

Methods

• The surveillance plan involved a systematic monitoring of the

water system in all buildings of the hospital associated with

patient care.

• From 2009, the surveillance was implemented and a

multidisciplinary infection control group (physicians, nurses,

engineers, chemists, technicians and commercial vendor of

disinfection technology) were involved in management of

Legionella at our Institution

Copper Silver ionization

During the first period of the

study (January 2002 through

September 2009) the

disinfection system of the hot

water circuit was copper-

silver ionization flow cell

(Tarn-Pure TM)

Chlorine Dioxide technologies

The second period of the study was from October 2009 to

July 2014. A total of 15 chlorine dioxide generation units

(Grundfos/BIOH TM) were installed in all buildings, according

to patients exposure and past laboratory evidence.

Chlorine Dioxide technologies

Chlorine Dioxide technologies

In order to improve

the efficacy of the

chlorine dioxide,

we used a special

filtration system

installed at the

entry of the

hot water distribution

system

Chlorine Dioxide technologies

In addition, a

phosphate compound

was added to the hot

water system to control

corrosion of, and

damage to, the water

pipes

Point Of Use Filtration

For Critical Units can

be added specific

single use filters

(anti.bacterical) for

more safety of the

patients

Positive

Samples (n.)

Negative

Samples (n.)

Overall

(n.)

Positive

%

2000 13 26 39 33%

2001 6 24 30 20%

2002 9 29 38 24%

2003 8 20 28 29%

2004 9 20 29 31%

2005 17 7 24 71%

2006 8 23 31 26%

2007 6 17 23 26%

2008 32 71 103 31%

2009 36 47 83 43%

2010 59 65 124 48%

2011 19 127 146 13%

2012 27 158 185 15%

2013 20 168 188 11%

2014 17 137 154 11%

Water sampling results for Legionella spp

33%

20%

24%

29% 31%

71%

26% 26%

31%

43%

48%

13% 15%

11% 11%

0%

10%

20%

30%

40%

50%

60%

70%

80%

2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014

Superheating (to 60°C) and Hyperchlorination (to 50ppm)

Copper-Silver Ionization

Chlorine dioxide

Distal environmental sites positive (%),

2000-2014

33%

20%

24%

29% 31%

71%

26% 26%

31%

43%

48%

13% 15%

11% 11%

0%

10%

20%

30%

40%

50%

60%

70%

80%

2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014

Percentage of distal sites positive for Legionella spp

during the study period

Positive

samples

Negative

samples Overall % of positivity

Verified

cases

Cardiosurgery + ICU1 7 59 66 11% 2 (2010)

NEW building 0 134 134 0%

OLD building for

medicine and surgery 31 65 96 32% 1 (2011)

ICU2 31 48 79 39%

Ophtalmic Clinic 6 23 29 21%

Palliative care 21 61 82 26% 1 (2011)

Infectious Diseases 17 64 81 21% 1 (2011)

Respiratory Diseases 7 40 47 15%

Pediatrics 2 40 42 5%

Haematology 0 38 38 0% 1 (2014)

Otolaringology 0 23 23 0%

Building for private pts 1 14 15 7%

Obstetrics 19 46 65 29%

Distribution of distal sites positive and nosocomial cases

from 2010 to 2014 among departments

Percentage of water cultures positive for Legionella spp among

hospital wards (2010-2014)

11%

0%

32%

39%

21%

26%

21%

15%

5%

0% 0%

7%

29%

0%

5%

10%

15%

20%

25%

30%

35%

40%

45%

Association between Legionella pneumophila < 1000 UFC/L and

concentrations of chlorine dioxide (ROC)

AUC 0.86 (IC95% 0.81-0.91); cut off 0.12 ppM

• ROC-curve shows at 0.12 ppm

the desirable cut-off, in terms of

cost-efficacy, in order to maintain

concentration <1000 UFC/L

• 0.18 ppm concentration allows

major bacterial reduction to

prevent disease in at-risk Units

Nosocomial and notified cases from 2000 to 2014

• According to the scientific literature,

copper-silver ionization and chlorine

dioxide achieved significant Legionella

reduction in the water system, and no

cases of hospital-acquired Legionellosis

• Copper silver ionization is very

expensive (230.000€/year) compared

with chlorine dioxide (120.000€/year)

Conclusions

• Several reports showed the efficacy of

systemic disinfection technologies (eg.

Chlorine dioxide, copper-silver ionization

etc.)

• None of the studies revealed negative long-

term effects (corrosion, calcification etc.) on

the water pipes

Conclusions

Effects of copper-silver ionization

Effects of copper-silver ionization

Effects of copper-silver ionization

• The long term effects of copper-silver

ionization could be corrosion of the hot

water system and costs for hospital settings

• Our study confirms the efficacy of chlorine

dioxide for controlling Legionella

colonization without negative effects on the

water pipes (corrosion)

Conclusions

• Thank you for your attention and best wishes from Pavia and her old Institutions:

Remarks

San Matteo Hospital 1449 University of Pavia 1361