MONDAY, March 24 (HealthDay News) -- The use of fluoroquinones to treat children with multidrug-resistant tuberculosis can lead to the development of drug-resistant invasive pneumococcal disease, including severe pneumonia and meningitis.

That finding emerged from a study by researchers at the National Institute for Communicable Diseases in South Africa.

They analyzed 21,521 cases of children with invasive pneumococcal disease and screened 19,404 isolates (90 percent of all cases) for resistance to ofloxacin (a fluoroquinone). Minimum inhibitory concentrations (MIC) for all isolates were measured, and levofloxacin resistance was defined as an MIC of 4mg/L or more. The researchers assessed nose and throat pneumococcal carriage in 65 children in two TB hospitals where invasive pneumococcal disease caused by levofloxacin-resistant Streptococcus pneumoniae had been detected.

Twelve cases of invasive pneumococcal disease were identified as levofloxacin-resistant, all in children younger than 15 years old. There were five deaths among the 11 patients whose outcomes were known.

The researchers found that invasive pneumococcal disease caused by levofloxacin-resistant S. pneumoniae was associated with a history of TB treatment. Eight out of nine (89 percent) children with non-susceptible isolates had a history of TB treatment, compared to 396 of 2,202 (18 percent) of children with susceptible isolates. Among the hospitalized children with nose and throat pneumococcal carriage, nearly 100 percent of the bacteria were levofloxacin resistant.

"Our data suggest that the use of fluoroquinones to treat multidrug-resistant tuberculosis in children has led to the emergence of invasive pneumococcal diseases caused by levofloxacin-non-susceptible S. pneumoniae and its nosocomial spread among children," the researchers concluded.

The study was published by The Lancet and released Monday to coincide with World TB Day.

More information

The U.S. National Foundation for Infectious Diseases has more about pneumococcal disease.