Journal Articles

Herold BC, Immergluck LC, Maranan MC, et al. Community-acquired methicillin-resistant Staphylococcus aureus in children with no identified predisposing risk. JAMA 1998; 279:593-598.

The prevalence of community-acquired methicillin-resistant Staphylococcus aureus may be increasing, according to this study.

Researchers compared records of children hospitalized at the University of Chicago Children's Hospital between 1988 and 1990 with records of children hospitalized at the same hospital between 1993 and 1995 to see if there was an increase in the number of children acquiring the drug-resistant staph infection outside the hospital.

They found eight children from the first three-year period with community-acquired MRSA infection and 35 from the latter three-year period with community-acquired infection. They also observed an increase in the number of toddlers afflicted.

MRSA afflicts virtually all hospitals

"Although such infections were once concentrated in relatively few large, university-based teaching hospitals, now 97% of such institutions report the presence of MRSA isolates," the authors note.

Children were classified as having "identified risk" of acquiring the infection if they had any of the following: previous hospitalization or antimicrobial therapy within six months of the date of MRSA isolation, history of endotracheal intubation, underlying chronic disorder, presence of an indwelling venous or urinary catheter, a history of any surgical procedure, or a notation in the medical record of a household contact with an identified risk factor. Only one of the 1988-1990 cases lacked an identified risk factor, whereas 25 of the cases in 1993-1995 lacked an identified risk factor.

A community-acquired MRSA isolate was identified as a staph specimen obtained from a patient within 72 hours of admission to the hospital.

Boyce JM. Are the epidemiology and microbiology of methicillin-resistant Staphylococcus aureus changing? JAMA 1998; 279:623-624.

In an editorial accompanying the article on community-acquired methicillin-resistant Staphylococcus aureus cited in the journal review above, the author suggests some of the cases may have actually been nosocomial due to prolonged colonization with MRSA.

Children were classified as having "identified risk" of acquiring the infection if they had hospitalization or antimicrobial therapy within six months of the date of MRSA isolation. That window may not been long enough to differentiate between community-acquired and nosocomial cases.

"Adults who acquire MRSA while hospitalized and who require readmission to the hospital are frequently still colonized with the same strain at the time of readmission," the author notes. "In one study of such patients, the median duration of MRSA colonization was 3.5 years."

Two other studies that found the most common risk factor associated with having MRSA at the time of admission to a hospital was exposure to a health care facility within the preceding 12 months, he adds. Larger community-based studies are needed to confirm whether transmission of MRSA strains is occurring more frequently in community settings, he concludes.

Genne D, Siegrist HH. Tuberculosis of the thumb following a needlestick injury. Clin Infect Dis 1998; 26:210

Describing a rare case of transmission of localized tuberculosis via needlestick, the authors underscore the need for infection control measures in laboratory settings to prevent such accidents.

The lab technician received a cervical lymph node for microbiological analysis from an HIV-positive, severely immunocompromised patient who had active pulmonary tuberculosis. A mycobacterial culture was requested.

While trying to insert the needle through the membrane of the bottle, the technician stuck it deeply into the tip of his left thumb, touching the bone. He accidentally injected a bolus of the liquid deeply into his finger. Ten days after the needlestick the technician felt numbness at the site of the wound. The acid-fast bacilli in the lymph node were identified as Mycobacterium tuberculosis. Susceptibility tests showed that the organisms were susceptible to the four principal antituberculous drugs - isoniazid, rifampin, ethambutol, and pyrazinamide.

Infection with tuberculosis by direct injection is rare. The skin is naturally resistant to tuberculosis; therefore, a breach of the cutaneous barrier is necessary to provoke infection. This can occur following circumcision, tattooing, intramuscular injection, or mouth-to-mouth resuscitation, the authors note.

"To our knowledge, only one [previous] case has been described where a syringe used on an HIV-positive patient with tuberculosis caused an accidental infection," they conclude. "In that case, a nurse injured herself with the needle of a catheter removed from an HIV-positive patient with pulmonary tuberculosis."

The condition of the technician's thumb improved slowly while he was treated with 300 mg of isoniazid and 600 mg of rifampin daily for six months. The pain progressively disappeared and no bone involvement was seen. It took more than one year, however, for complete recovery from the needlestick.