Differences between Staphylococcus aureus Isolates from Medical and Nonmedical Hospital Personnel

Abstract

It is unclear whether the levels of Staphylococcus aureus colonization of hospital personnel with patient exposure are increased or whether personnel become colonized with more antibiotic-resistant strains. Differences in nasal and hand carriage of S. aureus between medical and nonmedical hospital personnel were examined. No differences in nasal carriage between the two groups were found; however, there was a trend that suggested differences in the rates of hand carriage of S. aureus (18% of nonmedical personnel and 10% of medical personnel). Medical personnel were colonized with more antibiotic-resistant isolates than nonmedical personnel (mean, 2.8 versus 2.1 isolates [P < 0.03]), and the strain profiles indicated that they tended to be more clonal in origin, suggesting that exposure to hospital isolates alters the colonization profile.Staphylococcus aureus remains among the most important nosocomial pathogens because of both the diversity and the severity of the infections caused by these organisms (3, 11). Several studies have documented that these infections are most commonly caused by the patient's own commensal flora (9,18,20). The original reservoir(s) from which patients acquire these isolates remains unclear. While some infected patients are colonized with S. aureus at the time of hospitalization, others likely become colonized, often with more highly antibiotic-resistant isolates, during their hospital stays (3, 5, 7). Hospital personnel are among those implicated as possible sources of these potentially more antibiotic-resistant pathogens. Transmission of these strains to patients is then likely to occur during routine patient care. Despite the possible importance of this sequence of events, the questions of whether health care workers are more likely to be colonized with S. aureus and if these strains reflect those found in the hospital setting have received limited attention.In the present investigation, S. aureus colonization rates among hospital personnel were compared to address three questions. (i) Are medical personnel (MP) with regular exposure to patients more likely to be colonized than nonmedical personnel (NMP)? (ii) Are MP at greater risk than NMP of becoming colonized with more antibiotic-resistant isolates? (iii) Do the staphylococcal isolates collected from MP tend to be more clonal than those collected from NMP?Two hundred eighty employees of Montefiore Medical Center were screened for hand and nasal colonization with S. aureus between July 1999 and July 2000. Specimens for culture were collected at two sites: general medicine wards and an administrative site separate from the hospital. Only employees with direct patient contact were included in the MP group. Employees also completed a questionnaire concerning occupation, medical history, hand-washing behavior, and demographic information. The study was reviewed and approved by the Montefiore Medical Center Institutional Review Board.Specimens for culture were collected from the anterior nares with cotton swabs (Becton Dickinson Cult...

Associated risk factors and pulsed field gel electrophoresis of nasal isolates of Staphylococcus aureus from medical students in a tertiary hospital in Lagos, Nigeria

“…Cespedes et al [9] however found that hospital staff have higher incidence of hand and nasal colonization with S.aureus and could serve a vectors of S.aureus transmission to hospitalized patients. The results presented here may be attributed to the fact that the population comprises of medical student who are aware of the importance of handwashing in hospital environment.…”

“…For instance, a multivariate analysis of nasal carriage among otherwise healthy population particularly in hospital environment showed that the frequency of carriage among paramedics of the Sedgwick County Emergence Medical Service in Wichita, Kansas was approximately 50% and the incidence remained high during the course of the study [10]. A similar study indicated that medical personnel were colonized with more antibiotic-resistant isolates than nonmedical personnel and the strain profiles revealed that they tended to be more clonal in origin, suggesting that exposure to hospital isolates alters colonization profile [9].…”

“…There are considerable proofs that in healthcare settings, in-patients and hospital personnel are the main potential reservoirs of S.aureus. Basically, epidemiological pathways are from patients to healthcare worker to patients [8] and transmission to patients occurs during routine patient care [9]. For instance, a multivariate analysis of nasal carriage among otherwise healthy population particularly in hospital environment showed that the frequency of carriage among paramedics of the Sedgwick County Emergence Medical Service in Wichita, Kansas was approximately 50% and the incidence remained high during the course of the study [10].…”

High incidence rate of methicillin-resistant Staphylococcus aureus (MRSA) among healthcare workers in Saudi Arabia

“…S. aureus permanently colonizes the anterior nares of about 20% to 30% of the general population. Hospital workers are more likely to be colonized than persons in the general population, presumably because of increased exposure [7]. The resistance to antibiotics is due to a gene called mecA, which is part of the staphylococcal cassette chromosome.…”

Biofilm Formation in Multi-Drug Resistant Staphylococcus Aureus Isolates from Hospitalized Patients

“…In the hospital milieu, infected and colonized patients contribute to the transmission and spreading of S. aureus and hospital personnel, serving as reservoirs, facilitate further dissemination [1][2] . Infections caused by MRSA often prove difficult to treat because of high levels of resistance to multiple antibiotics as a result of both intrinsic and acquired mechanisms 3 .…”