the training facility where the outbreak occurred had a recruit population that fluctuated from 3,500 to 7,000 .
a case - patient was defined as a recruit with a clinically recognized skin or soft - tissue infection and a positive mrsa culture from the site of infection .
laboratory records showed that from october 2000 to july 2002 , 47 culture - confirmed mrsa infections occurred among recruits ( figure 1 ) . during this period ,
the monthly incidence of mrsa did not exceed two cases per 1,000 recruits ( figure 2 ) .
however , from august to december 2002 , 235 mrsa cases occurred . during the outbreak period ,
methicilin - resistant staphylococcus aureus ( mrsa ) incidence . of the case - patients , 209 ( 89% ) were men .
although information on the specific age of infected recruits was not available , all recruits at this facility were 1725 years of age .
most infections occurred on an extremity ( 73.7% ) , most commonly the lower leg ( 16.0% ) and the knee ( 13.9% ) ( table ) .
what aspects of training might be associated with transmission , cases were sorted by week of training when illness was diagnosed ( figure 3 ) .
data on training week was available for 143 ( 61% ) of the outbreak patients .
the rise in cases during weeks 15 suggests that transmission increased with time in training . of the cases , 86% occurred during weeks 6 to 12 but did not seem to be associated with any single event .
moderate increases occurred during weeks 6 and 7 ( rifle range training ) and week 11 , which included the  crucible ,  a 54-hour strenuous field exercise and final test before graduation .
these weeks include important milestones for recruits , and some may have delayed seeking medical care until after completing these steps .
* recruits arrive at the facility during ship week and undergo medical and administrative in - processing .
the diagnoses included abscesses ( 15 patients ) , cellulitis ( 2 patients ) , and folliculitis ( 3 patients ) .
the antimicrobial agents most commonly prescribed for initial treatment were dicloxacillin ( 6 ) , levofloxacin ( 5 ) , and ciprofloxacin ( 4 ) .
no patients had a history of hospitalization within the previous year , although one patient had been treated with levofloxacin for pneumonia 2 weeks before .
nasal screening was conducted to identify carriers and determine the colonization rate among staff members permanently assigned to the training facility .
anterior nasal swabs were obtained from 874 workers who had direct contact with recruits , including medical , dental , and laboratory personnel , drill instructors , barbers , and other ancillary staff . of these , 24 ( 2.7% )
were colonized with mrsa . through interviews with healthcare providers , laboratory personnel , and recruits , investigators found that most patients did not display established risk factors for mrsa ( history of chronic medical conditions , hospitalization or surgery within the previous year , history of drug use , or recent use of an antimicrobial agent ) . also , the mrsa isolates were sensitive to many commonly used outpatient antimicrobial agents , including trimethoprim / sulfamethoxazole and clindamycin . no recent lapses in recruit hygiene training or
however , this time was limited , perhaps leading to deficient hygiene practices among some recruits ( i.e. , inadequate showering , infrequent handwashing , sharing towels and other personal items ) . in november 2002 , facility personnel implemented an array of control measures with an emphasis on improving hygiene and treatment regimens .
based on existing recommendations for preventing mrsa transmission in healthcare settings ( 10 ) , antibacterial soaps and hand sanitizers were placed at all recruit sinks , and investigators recommended that hand washing be conducted as frequently as possible .
all recruits were issued personal bottles of antibacterial hand sanitizer for use when soap and water were not readily available .
daily showers of adequate duration were enforced , and sharing personal items such as towels and razors was prohibited .
in addition , local healthcare providers were alerted to the presence of mrsa among recruits .
patients were treated with the following regimen aimed at eliminating both mrsa infection and nasal carriage : oral rifampin and minocycline for 10 to 14 days , nasal mupirocin twice daily for 10 days , and hibiclens washes .
( trimethoprim / sulfamethoxazole could be substituted for minocycline . ) finally , preventive medicine staff conducted biweekly surveillance for mrsa cases by using laboratory records .
the actual number of cases as well as the incidence ( cases per 1,000 recruits ) declined by more than half in december 2002 and decreased further in january and february 2003 ( figure 1 , figure 2 ) .
this large outbreak demonstrates the threat of mrsa in a close - contact environment such as recruit training .
our findings are consistent with community - acquired , rather than nosocomial , mrsa infection ( 13,6 ) .
mrsa is spread by direct contact , most often through the hands of an infected or nasally colonized person ( 3 ) .
several recent community - acquired mrsa outbreaks have involved comparable close - contact environments ( 3,8,9 ) .
spread of community - acquired mrsa has also been associated with prolonged physical contact between sports participants ( 6,7 ) .
activities such as hand - to - hand combat training , life - saving , and team skill - building exercises involve similar physical contact between recruits .
the physical nature of recruit training is another factor that may have contributed to this outbreak .
recruits often have minor cuts or abrasions that increase the risk of developing skin infections .
such injuries would be expected during physically demanding activities such as running , hiking , and negotiating obstacle courses . indeed , most mrsa infections occurred on exposed surfaces such as arms , legs , and knees .
the growth and transmission of methicillin - sensitive s. aureus ( mssa ) , and accordingly mrsa , are increased in humid environments ( 11 ) .
the number of cases increased during warmer months , a time when recruits have more exposed skin surfaces .
this may increase their risk for superficial wounds as well as contact with other recruit s skin surfaces .
furthermore , some recruits reported that their infections started as insect bites , also a seasonal problem .
cases occurred throughout the facility and were not localized to recruits who had contact with a particular instructor or other staff member .
further , the percentage of staff members at the facility who were found to be carriers was small and consistent with the 2%3% mrsa carriage rates found in recent studies ( 9,12,13 ) .
although how much contact these carriers routinely had with recruits is unclear , this small number of patients was not likely a major factor in spreading mrsa across so many different groups of recruits .
in fact , the growing prevalence of mrsa in the general population ( 1,2,12,14 ) is an important concern because recruits may enter the military already colonized . maintaining good hygiene and avoiding contact with open skin lesions are the primary means to prevent the spread of mrsa infections ( 3,7 ) .
although no recent changes in recruit hygiene had occurred that were directly responsible for the outbreak , the hygiene deficiencies noted in some recruits combined with the increased prevalence of mrsa were important contributing factors .
control measures were instituted to improve hygiene , including frequent hand washing and the use of antibacterial hand sanitizers .
similar measures have been implemented to control mrsa outbreaks in comparable settings ( 3,6,7,15 ) . before august 2002
, healthcare providers did not routinely obtain bacterial identification and sensitivities on skin infections , possibly delaying effective treatment in some cases .
once aware that mrsa was prevalent among recruits , healthcare providers improved treatment by culturing skin lesions whenever possible and prescribing appropriate antimicrobial agents for mrsa infections .
thus , the primary interventions used were recommending improved hygiene practices for recruits and implementing aggressive clinical protocols . these control measures , along with the onset of cooler weather , likely played important roles in ending the outbreak .
this outbreak occurred in a previously healthy military training population and was associated with close contact , limited opportunity for practicing good personal hygiene , warm weather , and physical stress . reducing mrsa infections was related to implementing interventions to improve personal hygiene , aggressive evaluation and treatment of people with soft tissue injuries and infections , and cooler weather .
 we report an outbreak of 235 community - acquired methicillin - resistant staphylococcus aureus ( mrsa ) infections among military recruits . in this unique environment 
 , the close contact between recruits and the physical demands of training may have contributed to the spread of mrsa . 
 control measures included improved hygiene and aggressive clinical treatment . 
The Study
Conclusions