Table of Contents

Locator Record

Title: Methicillin-Resistant Staphylococcus aureus (MRSA) (L35_B )
Contact Number: 1-866-441-NCHS
Years of Content: 2001 - 2002
First Published: July, 2004
Revised: September, 2006
Access Constraints: None
Use Constraints: None
Geographic Coverage: National
Subject:Methicillin-Resistant Staphylococcus aureus (MRSA)
Record Source: NHANES 2001 - 2002
Survey Methodology: NHANES 2001 - 2002 is a stratified multistage probability sample of the civilian non-institutionalized population of the U.S.
Medium: NHANES Web site; SAS transport files

Component Description

Staphylococcus aureus is one of the most common causes of skin and soft tissue infection in both the health care and community settings. Antimicrobial resistance in S. aureus has increased dramatically, particularly in the hospital, where the rapid emergence of methicillin-resistant S. aureus (MRSA) and the appearance of S. aureus isolates with resistance to vancomycin have led to concern that this organism may become untreatable with currently available antimicrobials. Previously limited to hospitals, MRSA infections have been increasingly reported in the community. However, no prospective, population-based prevalence study has been done to measure the prevalence of MRSA in the community, and no national surveillance exists to provide a reliable national population estimate.

Eligible Sample

Participants aged 1 year and older were tested.

Description of Laboratory Methodology

Nasal swabs were first examined for proper labeling and integrity; they were then plated on mannitol salt agar (MSA), a selective media for the isolation of S. aureus. MSA plates were incubated at 35°C for 48 hours. Mannitol fermenting colonies (yellow or gold) were selected from the MSA plates and subcultured to trypticase soy agar + 5% sheep blood plates (BAP) and incubated at 35°C overnight. MSA plates with little or no growth were re-incubated at 35°C overnight, and plates with non-mannitol fermenting growth were held at room temperature. These plates were reexamined the next day, and any yellow or gold colonies were subcultured to BAP.

Overnight cultures on BAP are first screened using Staphaurex, a rapid latex kit for the identification of S. aureus (Remel, Lenexa, KS). A tube coagulase test using rabbit plasma with (ethylenedinitrilo) tetraacetic acid (EDTA) is then performed on Staphaurex-negative isolates from BAP with morphology consistent with S. aureus and Staphaurex-positive isolates with morphology inconsistent with S. aureus (non-hemolytic). Staphaurex-positive isolates and Staphaurex-negative tube coagulase-positive isolates are identified as S. aureus and saved for further testing. Staphaurex-positive, tube coagulase-negative isolates are discarded.
S. aureus isolates are screened for methicillin resistance following the National Clinical and Laboratory Standards Institute (NCCLS) disk diffusion method. Overnight cultures from BAP are plated on Mueller-Hinton (MH) agar, and a 1-μg oxacillin (OX) disk is placed on the inoculated plate. Zone diameters are measured and recorded after 24-h incubation at 35°C (susceptible, ≥ 13 mm; intermediate, 11 mm–12 mm; resistant, ≤ 10 mm).

Isolates resistant to OX (MRSA), intermediate to OX, and every 10th isolate susceptible to OX (MSSA) by disk diffusion are saved for additional testing of organism characteristics. These tests include antibiotic susceptibility testing (MIC) by using broth microdilution using NCCLS reference methods; strain typing by pulsed-field gel electrophoresis (PFGE) using SmaI enzyme; singleplex polymerase chain reaction (PCR) for detection of enterotoxins, toxic shock syndrome toxin-1, and Panton-Valentine leukocidin toxin; and SCC-mec cassette typing by PCR.

Data Processing and Editing

Nasal swab specimens were processed, stored and shipped to Division of Healthcare Quality Promotion, National Center for Infectious Diseases, National Centers for Disease Control and Prevention, Atlanta, GA for analysis. Detailed specimen collection and processing instructions are discussed in the LPM. Read the LABDOC file for detailed data processing and editing protocols. The analytical methods are described in the Description of the Laboratory Methodology section.

Laboratory Quality Assurance and Monitoring

The NHANES quality control and quality assurance protocols (QA/QC) meet the 1988 Clinical Laboratory Improvement Act mandates. Detailed quality control and quality assurance instructions are discussed in the NHANES Laboratory/Medical Technologists Procedures Manual (LPM). Read the LABDOC file for detailed QA/QC protocols.

Analytic Notes

The analysis of NHANES 2001–2002 laboratory data must be conducted with the key survey design and basic demographic variables. The NHANES 2001–2002 Household Questionnaire Data Files contain demographic data, health indicators, and other related information collected during household interviews. They also contain all survey design variables and sample weights for these age groups. The phlebotomy file includes auxiliary information such as the conditions precluding venipuncture. The household questionnaire and phlebotomy files may be linked to the laboratory data file using the unique survey participant identifier SEQN.

S. aureus present and organism identified as MRSA

If LBXMS1 = 1 and LBXM1 = 1, further organism characteristic testing was performed.
Isolates resistant to OX (i.e., MRSA), isolates intermediate to OX, and every 10th isolate susceptible to OX (i.e., MSSA) by disk diffusion were saved for additional testing of organism characteristics. These tests include antimicrobial susceptibility testing (minimum inhibitory concentration [MIC]) by broth microdilution using NCCLS reference methods; strain typing by pulsed field gel electrophoresis (PFGE) using SmaI enzyme; singleplex polymerase chain reaction (PCR) for detection of enterotoxins, toxic shock syndrome toxin-1, and Panton-Valentine leukocidin toxin; and SCC-mec cassette typing by PCR.

S. aureus present and organism identified as MSSA

Every 10th isolate susceptible to OX (i.e., MSSA) by disk diffusion was saved for additional testing of organism characteristics. These tests include antimicrobial susceptibility testing (MIC) by broth microdilution using NCCLS reference methods; strain typing by PFGE using SmaI enzyme.

Other organism characteristic (e.g., enterotoxin) testing is still in progress. These data will be added to this file in a future release.

References

Codebook and Frequencies

SEQN - Respondent sequence number

Variable Name:
SEQN
SAS Label:
Respondent sequence number
English Text:
Respondent sequence number.
Target:
Both males and females 1 YEARS - 150 YEARS

LBXMS1 - S. aureus present 1

Variable Name:
LBXMS1
SAS Label:
S. aureus present 1
English Text:
S. aureus present 1
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Yes 2964 2964
2 No 6658 9622
. Missing 307 9929

LBXM1 - MRSA 1

Variable Name:
LBXM1
SAS Label:
MRSA 1
English Text:
MRSA 1
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Yes 75 75
2 No 2889 2964
. Missing 6965 9929

LBXMT1 - Tetracycline 1

Variable Name:
LBXMT1
SAS Label:
Tetracycline 1
English Text:
Tetracycline 1
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Sensitive 356 356
2 Resistant 12 368
3 Intermediate 4 372
4 No Result 0 372
. Missing 9557 9929

LBXMZ1 - Trimethoprim/Sulfamethoxazole 1

Variable Name:
LBXMZ1
SAS Label:
Trimethoprim/Sulfamethoxazole 1
English Text:
Trimethoprim/Sulfamethoxazole 1
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Sensitive 372 372
2 Resistant 0 372
3 Intermediate 0 372
4 No Result 0 372
. Missing 9557 9929

LBXMC1 - Clindamycin 1

Variable Name:
LBXMC1
SAS Label:
Clindamycin 1
English Text:
Clindamycin 1
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Sensitive 348 348
2 Resistant 24 372
3 Intermediate 0 372
4 No Result 0 372
. Missing 9557 9929

LBXME1 - Erythromycin 1

Variable Name:
LBXME1
SAS Label:
Erythromycin 1
English Text:
Erythromycin 1
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Sensitive 255 255
2 Resistant 116 371
3 Intermediate 1 372
4 No Result 0 372
. Missing 9557 9929

LBXMP1 - Penicillin 1

Variable Name:
LBXMP1
SAS Label:
Penicillin 1
English Text:
Penicillin 1
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Sensitive 37 37
2 Resistant 335 372
3 Intermediate 0 372
4 No Result 0 372
. Missing 9557 9929

LBXMI1 - Imipenem 1

Variable Name:
LBXMI1
SAS Label:
Imipenem 1
English Text:
Imipenem 1
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Sensitive 301 301
2 Resistant 71 372
3 Intermediate 0 372
4 No Result 0 372
. Missing 9557 9929

LBXMV1 - Vancomycin 1

Variable Name:
LBXMV1
SAS Label:
Vancomycin 1
English Text:
Vancomycin 1
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Sensitive 372 372
2 Resistant 0 372
3 Intermediate 0 372
4 No Result 0 372
. Missing 9557 9929

LBXMF1 - Cefazolin 1

Variable Name:
LBXMF1
SAS Label:
Cefazolin 1
English Text:
Cefazolin 1
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Sensitive 301 301
2 Resistant 71 372
3 Intermediate 0 372
4 No Result 0 372
. Missing 9557 9929

LBXMO1 - Oxacillin 1

Variable Name:
LBXMO1
SAS Label:
Oxacillin 1
English Text:
Oxacillin 1
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Sensitive 297 297
2 Resistant 75 372
3 Intermediate 0 372
4 No Result 0 372
. Missing 9557 9929

LBXMG1 - Gentamicin 1

Variable Name:
LBXMG1
SAS Label:
Gentamicin 1
English Text:
Gentamicin 1
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Sensitive 371 371
2 Resistant 1 372
3 Intermediate 0 372
4 No Result 0 372
. Missing 9557 9929

LBXMD1 - Ciprofloxacin 1

Variable Name:
LBXMD1
SAS Label:
Ciprofloxacin 1
English Text:
Ciprofloxacin 1
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Sensitive 327 327
2 Resistant 42 369
3 Intermediate 3 372
4 No Result 0 372
. Missing 9557 9929

LBXML1 - Levofloxacin 1

Variable Name:
LBXML1
SAS Label:
Levofloxacin 1
English Text:
Levofloxacin 1
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Sensitive 330 330
2 Resistant 28 358
3 Intermediate 14 372
4 No Result 0 372
. Missing 9557 9929

LBXMR1 - Rifampin 1

Variable Name:
LBXMR1
SAS Label:
Rifampin 1
English Text:
Rifampin 1
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Sensitive 371 371
2 Resistant 1 372
3 Intermediate 0 372
4 No Result 0 372
. Missing 9557 9929

LBXMY1 - Amoxicillin/k Clavulanate 1

Variable Name:
LBXMY1
SAS Label:
Amoxicillin/k Clavulanate 1
English Text:
Amoxicillin/K Clavulanate 1
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Sensitive 301 301
2 Resistant 71 372
3 Intermediate 0 372
4 No Result 0 372
. Missing 9557 9929

LBAMMT1 - Molecular type 1

Variable Name:
LBAMMT1
SAS Label:
Molecular type 1
English Text:
Molecular Type 1
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
Molecular type 1 Value was recorded 373 373
< blank > Missing 9556 9929

LBXMS2 - S. aureus present 2

Variable Name:
LBXMS2
SAS Label:
S. aureus present 2
English Text:
S. aureus present 2
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Yes 22 22
2 No 0 22
. Missing 9907 9929

LBXMT2 - Tetracyline 2

Variable Name:
LBXMT2
SAS Label:
Tetracyline 2
English Text:
Tetracyline 2
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Sensitive 0 0
2 Resistant 0 0
3 Intermediate 0 0
4 No Result 0 0
. Missing 9929 9929

LBXMZ2 - Trimethoprim/Sulfamethoxazole 2

Variable Name:
LBXMZ2
SAS Label:
Trimethoprim/Sulfamethoxazole 2
English Text:
Trimethoprim/Sulfamethoxazole 2
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Sensitive 0 0
2 Resistant 0 0
3 Intermediate 0 0
4 No Result 0 0
. Missing 9929 9929

LBXMC2 - Clindamycin 2

Variable Name:
LBXMC2
SAS Label:
Clindamycin 2
English Text:
Clindamycin 2
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Sensitive 0 0
2 Resistant 0 0
3 Intermediate 0 0
4 No Result 0 0
. Missing 9929 9929

LBXME2 - Erythromycin 2

Variable Name:
LBXME2
SAS Label:
Erythromycin 2
English Text:
Erythromycin 2
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Sensitive 0 0
2 Resistant 0 0
3 Intermediate 0 0
4 No Result 0 0
. Missing 9929 9929

LBXMP2 - Penicillin 2

Variable Name:
LBXMP2
SAS Label:
Penicillin 2
English Text:
Penicillin 2
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Sensitive 0 0
2 Resistant 0 0
3 Intermediate 0 0
4 No Result 0 0
. Missing 9929 9929

LBXMI2 - Imipenem 2

Variable Name:
LBXMI2
SAS Label:
Imipenem 2
English Text:
Imipenem 2
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Sensitive 0 0
2 Resistant 0 0
3 Intermediate 0 0
4 No Result 0 0
. Missing 9929 9929

LBXMV2 - Vancomycin 2

Variable Name:
LBXMV2
SAS Label:
Vancomycin 2
English Text:
Vancomycin 2
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Sensitive 0 0
2 Resistant 0 0
3 Intermediate 0 0
4 No Result 0 0
. Missing 9929 9929

LBXMF2 - Cefazolin 2

Variable Name:
LBXMF2
SAS Label:
Cefazolin 2
English Text:
Cefazolin 2
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Sensitive 0 0
2 Resistant 0 0
3 Intermediate 0 0
4 No Result 0 0
. Missing 9929 9929

LBXMO2 - Oxacillin 2

Variable Name:
LBXMO2
SAS Label:
Oxacillin 2
English Text:
Oxacillin 2
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Sensitive 0 0
2 Resistant 0 0
3 Intermediate 0 0
4 No Result 0 0
. Missing 9929 9929

LBXMG2 - Gentamicin 2

Variable Name:
LBXMG2
SAS Label:
Gentamicin 2
English Text:
Gentamicin 2
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Sensitive 0 0
2 Resistant 0 0
3 Intermediate 0 0
4 No Result 0 0
. Missing 9929 9929

LBXMD2 - Ciprofloxacin 2

Variable Name:
LBXMD2
SAS Label:
Ciprofloxacin 2
English Text:
Ciprofloxacin 2
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Sensitive 0 0
2 Resistant 0 0
3 Intermediate 0 0
4 No Result 0 0
. Missing 9929 9929

LBXML2 - Levofloxacin 2

Variable Name:
LBXML2
SAS Label:
Levofloxacin 2
English Text:
Levofloxacin 2
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Sensitive 0 0
2 Resistant 0 0
3 Intermediate 0 0
4 No Result 0 0
. Missing 9929 9929

LBXMR2 - Rifampin 2

Variable Name:
LBXMR2
SAS Label:
Rifampin 2
English Text:
Rifampin 2
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Sensitive 0 0
2 Resistant 0 0
3 Intermediate 0 0
4 No Result 0 0
. Missing 9929 9929

LBXMY2 - Amoxicillin/k Clavulanate 2

Variable Name:
LBXMY2
SAS Label:
Amoxicillin/k Clavulanate 2
English Text:
Amoxicillin/k Clavulanate 2
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Sensitive 0 0
2 Resistant 0 0
3 Intermediate 0 0
4 No Result 0 0
. Missing 9929 9929

LBAMMT2 - Molecular type 2

Variable Name:
LBAMMT2
SAS Label:
Molecular type 2
English Text:
Molecular type 2
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
< blank > Missing 9929 9929

LBXETA - Enterotoxin A

Variable Name:
LBXETA
SAS Label:
Enterotoxin A
English Text:
Enterotoxin A
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Positive 70 70
2 Negative 302 372
. Missing 9557 9929

LBXETB - Enterotoxin B

Variable Name:
LBXETB
SAS Label:
Enterotoxin B
English Text:
Enterotoxin B
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Positive 23 23
2 Negative 349 372
. Missing 9557 9929

LBXETC - Enterotoxin C

Variable Name:
LBXETC
SAS Label:
Enterotoxin C
English Text:
Enterotoxin C
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Positive 19 19
2 Negative 353 372
. Missing 9557 9929

LBXETD - Enterotoxin D

Variable Name:
LBXETD
SAS Label:
Enterotoxin D
English Text:
Enterotoxin D
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Positive 58 58
2 Negative 314 372
. Missing 9557 9929

LBXETE - Enterotoxin E

Variable Name:
LBXETE
SAS Label:
Enterotoxin E
English Text:
Enterotoxin E
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Positive 0 0
2 Negative 372 372
. Missing 9557 9929

LBXETH - Enterotoxin H

Variable Name:
LBXETH
SAS Label:
Enterotoxin H
English Text:
Enterotoxin H
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Positive 17 17
2 Negative 355 372
. Missing 9557 9929

LBXTSS - Toxic Shock Syndrome Toxin 1

Variable Name:
LBXTSS
SAS Label:
Toxic Shock Syndrome Toxin 1
English Text:
Toxic Shock Syndrome Toxin 1
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Positive 95 95
2 Negative 277 372
. Missing 9557 9929

LBXPVL - Panton Valentine Leukocidin

Variable Name:
LBXPVL
SAS Label:
Panton Valentine Leukocidin
English Text:
Panton Valentine Leukocidin
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Positive 9 9
2 Negative 363 372
. Missing 9557 9929

LBXSCC - SCCmec Type

Variable Name:
LBXSCC
SAS Label:
SCCmec Type
English Text:
SCCmec Type
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Type I 0 0
2 Type II 38 38
3 Type III 0 38
4 Type IV-No Subtype 14 52
5 Type Iva 14 66
6 Type Ivb 7 73
7 Type Ivc 2 75
8 Not Typable 0 75
. Missing 9854 9929