NCBI Bookshelf. A service of the National Library of Medicine, National Institutes of Health.

Holzheimer RG, Mannick JA, editors. Surgical Treatment: Evidence-Based and Problem-Oriented. Munich: Zuckschwerdt; 2001.

Cover of Surgical Treatment

Surgical Treatment: Evidence-Based and Problem-Oriented.

Show details

Methicillin-resistant staphylococcus aureus

and .

Author Information

The susceptibility pattern of microbiological pathogens and their species have changed in the last decades. With the advent of penicillin and thereafter broad spectrum antibiotics, Gram negative nosocomial infections became the greatest threat to the patients in the intensive care unit (ICU), which became routine care facilities in the sixties. It is apparent that there is a shift in the pathogens from Gram- to Gram+ and towards the year 2000 physicians will be more and more confronted with colonisation and infection with methicillin resistant Staphylococcus aureus (MRSA), and by consequence we are increasingly forced to use vancomycin as a primary treatment (7). This is an expensive drug with toxic side-effects necessitating the measurements of bloodlevels for its dosage. Unfortunately sporadic vancomycinresistance already has been reported in MRSA as well as in methicillin resistant Staphylococcus epidermidis (MRSE) and enterococci. The presence of MRSA is related to prolonged or inadequate (mis)use of antimicrobial agents and this also explains the difference in incidence in the European countries (table I). The prescription of broad spectrum antimicrobial agents to which MRSA is resistant (for instance selective decontamination of the gut) will cause selection and provokes an increase in the incidence of colonisation and infections with MRSA (5, 8, 9). The respiratory tract still is the most common localisation of infections in the ICU as was found in an infection prevalence study of 10,038 intensive care patients on 29.04.1992: the EPIC study (2, 10). Risk for MRSA acquired infection is independent of the type of ICU but correlates significantly to severity of illness, predominantly in patients with an APACHE II score of 6–30 and long duration of stay on the ICU (2, 6) (table III).

Table I. Number of patients in ICU by country, percentage incidence of ICU-acquired infection, incidence of MRSA as a percentage of total isolates of S. aureus, and percentage of mortality.

Table I

Number of patients in ICU by country, percentage incidence of ICU-acquired infection, incidence of MRSA as a percentage of total isolates of S. aureus, and percentage of mortality.

Table III. Percentage prevalence of MRSA and MSSA ICU-acquired infection and odds ratio of risk of developing MRSA infection compared to MSSA depending on APACHE II score and length of stay in ICU.

Table III

Percentage prevalence of MRSA and MSSA ICU-acquired infection and odds ratio of risk of developing MRSA infection compared to MSSA depending on APACHE II score and length of stay in ICU.

The question remains if there is a difference between the morbidity and mortality of patients suffering from MRSA and MSSA (methiycillin sensitive Staphylococcus aureus). To answer this question the material of the EPIC study was analysed specifically (Ibelings and Bruining 1998). Most infections were found in the respiratory tract (table II), but the flaw here is that the study design did not separate colonisation and infection very well. Staphylococci found in the urinary tract most certainly are colonisers as practically all patients had properly functioning indwelling bladdercatheters. On the other hand it is notable that the amount of wound-infections is equal in both MRSA and MSSA groups, where one may assume that vancomycin has not been used prophylactically. The most important risk-factor for an ICU-acquired MRSA infection is the length of stay in the ICU as the chance to get infected practically rises exponentionally with time in the ICU (table III). We also found that the mortality rate in MRSA infected patients is higher (32%) compared to MSSA infections (25%) (table IV).

Table II. Reported types of ICU-acquired infection by MRSA and MSSA.

Table II

Reported types of ICU-acquired infection by MRSA and MSSA.

Table IV. Percentage mortality according to site in MRSA and MSSA ICU-acquired infections and odds ratio of survival from the MRSA infections compared to MSSA (death = OR 1).

Table IV

Percentage mortality according to site in MRSA and MSSA ICU-acquired infections and odds ratio of survival from the MRSA infections compared to MSSA (death = OR 1).

Can MRSA infections be prevented (50% of the normal population bears Staphylococcus aureus)? In countries where MRSA is not endemic (see table I) routine surveillance and strict isolation of MRSA carriers can be successfully employed. Patients who are repatriated from hospitals known to harbour MRSA must be strictly isolated and nasal, perineal and wound-discharge culture must be negative for MRSA three times every other day before isolation can be lifted. In countries where MRSA is endemic all patients admitted to high-risk hospital areas (as an ICU) must be screened on admission and during their stay on the ICU (3, 4). Eradication involves isolation, barrier nursing, skin decolonisation using chlorhexidine and mupirocin treatment of nasal carriers of MRSA, as nasal carriage of Staphylococcus aureus (even in patients undergoing elective cardiac surgery) bears an increased risk of becoming infected, increasing morbidity and mortality and narrowing down the therapeutical boundaries of antimicrobial treatment.

Acquisition of MRSA is strongly increased after an ICU stay of more than 2 weeks (table III).

Overall mortality is not significantly increased in ICU patients with MRSA infections. In a subgroup with lower respiratory tract infections mortality is significantly higher than with MSSA infections (table III).

The data in this chapter are used from the European Journal of Surgery with permission of the Editor.

References

1.
Archer G L. Staphylococcus aureus: A well-armed pathogen. Clin Infect Dis. (1998);26:1179–1181. [PubMed: 9597249]
2.
Brun-Buisson C. Advances and controversies in the epidemiology, diagnosis and prevention of nosocomial pneumonia in the ICU. Curr Opin Crit Care. (1995);1:341–348.
3.
Corbella X, Dominguez M A, Pujol M, Aayats J, Sendra M, Pallares R, Ariza J, Gudiol F. Staphylococcus aureus nasal carriage as a marker for subsequent staphylococcal infections in intensive care unit patients. Eur J Microbiol Infect Dis. (1997);16:351–357. [PubMed: 9228474]
4.
Girou E, Pujade G, Legrand P, Cizeau F, Brun-Buisoon C. Selective screening of carriers for control of methicillin-resistent Staphylococcus aureus (MRSA) in high-risk hospital areas with a high level of endemic MRSA. Clin Infect Dis. (1998);27:543–550. [PubMed: 9770155]
5.
Hiramatsu K. Vancomycin resistent in Staphylococci. Drug Resistance Updates. (1998);1:135–150. [PubMed: 16904400]
6.
Ibelings M M S, Bruining H A. Methicillin-resistant Staphylococcus aureus: acquisition and risk of death in patients in the intensive care unit. Eur J Surg. (1998);164:411–418. [PubMed: 9696441]
7.
Lowy F D. Staphylococcus aureus infections. N Engl J Med. (1998);339:520–532. [PubMed: 9709046]
8.
Manhold C, Rolbicki U v, Brase R, Timm J, Pritzbuer E v, Heimesaat M, Kljucar S (1998) Intens Care Med 24: 1327–1330 . [PubMed: 9885888]
9.
Smith T L, Pearson M L, Wilcox K R, Cosme Cruz P H, Lancaster M V, Robinson-Dunn B, Teover F C, Zervos M J, Band J D, White E, Jarvis W R. Emergence of vancomycin resistance in Staphylococcus aureus. New Engl J Med. (1999);340:493–502. [PubMed: 10021469]
10.
Vincent J -L, Bihani D J, Suten P M, Bruining H A, White J, Nicolas-Chanoin M H, Wolf M, Spencer R C, Hemmer M. The prevalence of nosocromial infection in Intensive Care Units in Europe. JAMA. (1995);274:639–644. [PubMed: 7637145]
Copyright © 2001, W. Zuckschwerdt Verlag GmbH.
Bookshelf ID: NBK6897

Views

  • PubReader
  • Print View
  • Cite this Page

Related information

Recent Activity

Your browsing activity is empty.

Activity recording is turned off.

Turn recording back on

See more...