Hospital acquired infection : Molecular study and

infection control guidelines

Mahmoud L A ¹ , Salama O S 2

, Abdel Ghaffar HA 3, Elemshaty

W M 4 , Murad M H

4 and Shady A I

5

¹ Prof of Clinical Pathology Faculty of Medicine-Mansoura University

2 Prof of Clinical Pathology Faculty of Medicine-Mansoura University

3 Head of Clinical Pathology Department Faculty of Medicine-Mansoura

University

4 Associate Prof of Clinical Pathology Faculty of Medicine- Mansoura

University

4 Prof of Clinical Pathology Faculty of Medicine- Zagazig University

5 Resident in Clinical Pathology Department Faculty of Medicine-

Mansoura University

Abstract

This article discuss morbidity, mortality , infections

routes and medical cost associated with hospital

acquired infections , with stress on molecular studies

along with infection control guidelines.

Conclusion

The evaluation of HAIs will continue to rely on

surveillance .Outbreak Control & Isolation precautions

, waste management, product evaluation and

disinfection, sterilization and asepsis are integrated

component of infection control program .

Acknowledgement

Special thanks to Prof . Dr Salah agha Head of

Clinical microbiology unit of Clinical Pathology

Department Faculty of Medicine-Mansoura University

who reviewed this work .

Accepted July 2012

Published May 2013

long term hospitalizations, surgical

procedures, receipt of prior

antimicrobial therapy, and the presence

of indwelling catheters (Singh et al.,

2006) .

Understanding pathogen

distribution and relatedness is

essential for determining the

epidemiology of NI and aiding in the

design of rational pathogen control

methods. The role of pathogen typing

is to determine if epidemiologically

related isolates are also genetically

related . Historically, this analysis of

nosocomial pathogens has relied on a

comparison of phenotypic

characteristics such as biotypes ,

serotypes ,bacteriophage or bacteriocin

types, and antimicrobial susceptibility

profiles. This approach has begun to

change over the past 2 decades, with

the development and implementation

of new technologies based on DNA, or

molecular, analysis (Arbeit , 1999 &

Cockerill ,et al.,2004 ) . Most studies

related to HAI were conducted in the

developed countries and demonstrated

the efficacy of HAI surveillance and its

significant incidence concerning

patient morbidity and mortality (Cooke

, 2000 & Barrett , 2002 & Gastmeier

,2006) .

Hospital-acquired infections (HAIs) or

nosocomial infections (NI) are a major

challenge to patient safety and

contribute significantly to morbidity

and mortality, as well as to excess

costs for hospital stay (French and

Cheng , 1991) .They affect both

developed and resource-poor countries

and constitute a significant burden both

for the patient and for the health care

system (WHO, 2002) .

A prevalence survey was conducted,

under the authority of the World Heath

Organization (WHO), in 55 hospitals

from 14 countries representing 4

regions (Europe, Eastern

Mediterranean, Southeast Asia, and

Western Pacific). This survey revealed

that an average of 8.7% of hospitalized

patients developed HAIs, with the

highest frequencies of such infections

occurring among hospitals in the

Eastern Mediterranean and South east

Asian regions “11.8% and 10%

respectively” (Talaat , et al., 2006) .

Several risk factors for acquiring

an infection have been commonly

cited, including the presence of

underlying conditions (such as

diabetes, renal failure, or

malignancies),

Nosocomial infection (NI) or

hospital acquired infection (HAI) can

be defined as an infection acquired in

hospital by a patient who was admitted

for a reason other than that infection .

This includes infections acquired in the

hospital but appearing after discharge,

and also occupational infections among

staff of the facility (WHO, 2002) .

Nosocomial infection rates range from

1% in Northern Europe, especially the

Netherlands, which introduced

extremely aggressive infection control

measures, to 40% in some parts of

Asia, South America, and sub-Saharan

Africa (Starakis et al .,2002& Eriksen

et al .,2005& Klevens et al .,2007).

Compared with average prevalence

of health-care-associated infection in

Europe (reported as 7.1 per 100

patients by the European Centre for

Disease Prevention and Control) and

estimated incidence in the USA (4.5

per 100 patients ), prevalence of

health-care-associated infection in

resource-limited settings is

substantially higher, particularly in

high-quality studies (15.5 per 100

patients). The difference between

developing and developed countries is

even more striking when considering

incidence of ICU-acquired infection

(pooled density 47.9 per 1000 patient-

Conversely, in the developing

countries, few studies provide data of

device associated infection rates using

the standardized definitions of HAI

rates per 1000 days (Rosenthal etal . ,

2006 & Leblebicioglu etal . , 2007) .

More over, much of the recent

research on NI has dealt with the need

for new antibiotics ,better antibiotic

management and better diagnostic

techniques to detect infections earlier

.Better drug treatment and earlier

infection diagnosis can certainly play a

major role in reducing morbidity and

mortality from HAIs . However, there

are many non pharmacological

interventions that can significantly

reduce the incidence of HAIs, but these

are often overlooked in practice

(Curtis, 2008) .

The aim of this essay is to

review morbidity, mortality , infections

routes and medical cost associated

with hospital acquired infections , with

stress on molecular studies of these

infections along with infection control

guidelines.

The overall increase in the

duration of hospitalization for patients

with surgical wound infections was 8.2

days, ranging from 3 days for

gynaecology to 9.9 for general surgery

and 19.8 for orthopaedic surgery.

Prolonged stay not only increases

direct costs to patients or payers but

also indirect costs due to lost work

(Coello et al ., 1993). The increased

use of drugs, the need for isolation, and

the use of additional laboratory and

other diagnostic studies also contribute

to costs (Wenzel ,1995). NI is the

fourth commonest cause of in-hospital

deaths, after cardiovascular disease,

cancers and community-acquired

infections. Lower respiratory tract and

bloodstream infections were the main

sites of NI which contributed to death,

surgical-site infections were the third

most common factor contributing to

death. Conversely, urinary tract

infections rarely contribute to death,

although some of them could be

considered to play a role in fatal

outcomes, particularly when they were

associated with a bloodstream infection

.

days in developing countries), which is

estimated to be 13.6 per 1000 patient-

days in the USA (Klevens et al .,

2007). Importantly, very high rates

of health-care-associated infection in

neonatal and paediatric populations

were noted not only in ICUs but also in

some paediatric wards and children’s

hospitals (Cavalcante et al ., 2006).

In a nation wide study undertaken in

the USA, the cumulative incidence of

surgical-site infection was 2.6 per 100

surgical procedures; similarly, it was

2.9 per 100 surgical procedures in

different European countries, and 1.6

per 100 procedures in Germany . (

Bhutta et al ., 2005).

Figure 1 . Studies on general HAIs

rates from developing and developed

countries 1995-2008 (WHO 2008).

Examples of biological materials

that are analyzed in clinical

laboratories include whole blood ,

serum , plasma , urine , feces , saliva ,

spinal and other body fluid . All these

specimens also used for molecular

testing . Specimens devoid of patient

cells are useful in detection of

infectious agents (CLSI .,2006) .

Historically, this analysis of

nosocomial pathogens has relied on a

comparison of phenotypic

characteristics such as biotypes,

serotypes, bacteriophage or bacteriocin

types, and antimicrobial susceptibility

profiles. This approach has begun to

change over the past 2 decades, with

the development and implementation

of new technologies based on DNA, or

molecular, analysis. These DNA-based

molecular methodologies , include

pulsed-field gel electrophoresis

(PFGE) and other restriction-based

methods, plasmid analysis, and PCR-

based typing methods. The

incorporation of molecular methods for

typing of nosocomial patho-gens has

assisted in efforts to obtain a more

fundamental assessment of strain

interrelationship (Cockerill and Smith,

2004).

For infection to take place,

microorganisms must be transferred

from a reservoir to an acceptable entry

site on a susceptible host in sufficient

numbers (the infecting dose) for

multiplication of the agent to take

place. The infecting dose of a

microorganism may depend in varying

degrees on the infectivity,

pathogenicity, and virulence of the

microorganism itself. The entire

transmission process constitutes the

chain of infection. Within the

healthcare setting, the reservoir of an

agent may include patients themselves,

healthcare workers, tap water, soap

dispensers, mechanical ventilators,

intravenous devices and infusates,

multidose vials, and other factors in the

environment (Johnson and Gerding

,1998).

The highest prevalence of HAI

occurred in ICUs and acute care

surgical and orthopedic settings. Old

age, multiple morbidities or disease

severity, and decreased immunity

increase patient susceptibility. Poor

infection control measures , invasive

procedures including central venous or

urinary catheter placements ,and

antimicrobial misuse are another risk

factors (Wenzel , 2007 & Klevens et al

.,2007) .

all hospitals in Egypt by 2010 (Yassin

etal ., 2003).

The structure and components of

an infection control program are shown

in Tables 1, 2 and 3 . Several authors

have discussed the components of an

infection control program in the Long-

term care facilities (LTCF) . Most

authors feel that an infection control

program should include some form of

surveillance for infections, an epidemic

control program, education of

employees in infection control

methods, policy and procedure

formation and review, an employee

health program, a resident health

program, and monitoring of resident

care practices. The program also may

be involved in quality improvement,

patient safety, environmental review,

antibiotic monitoring, product review

and evaluation, resident safety,

prepareness planning, and reporting of

diseases to public health authorities

(Ouslander et al.,2006) .

Conclusion

There are issues of concern

about the emergence of

nosocomial infections, and the

increase in morbidity, mortality,

and costs associated with these

infections will drive the need for

refinement of molecular

approaches to aid in the

Figure 2. Recent evolution of

bacterial strain identification for

epidemiological purpose ( Belkum ,

2007)

Healthcare-associated infection

affects hundreds of millions of people

world wide and is a major global issue

for patient safety. It complicates

between 5 and 10% of admissions in

acute care hospitals in industrialized

countries. In developing countries, the

risk is two to twenty times higher and

the proportion of infected patients

frequently exceeds 25% . IC activities

are still developing in many health

institutions in Egypt. The national

infection control program was started

in 2003 by the Ministry of Health and

Population. The national IC strategic

plan entailed instituting IC programs in

and disinfection, sterilization

and asepsis are integrated

component of infection control

program.

Recommendations

Many non-pharmacological

interventions have been shown to

significantly reduce rates of HAIs, but

are often overlooked in clinical

practice so this article recommend ;

Proper hand washing

Better nutrition

Housing patients in separate

rooms

Sufficient numbers of nursing

staff

Coated urinary and CVCs

Lower overall antibiotic use

which will reduce risk of

antibiotic-resistant organisms

and improve efficacy of

antibiotics given to patients who

acquire nosocomial infections.

Molecular technique can be very

effective in tracing the spread of

nosocomial infection

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