The increase in carbapenem use and emergence of Stenotrophomonas maltophilia as an important nosocomial pathogen.

Carbapenems, being the broadest spectrum antibiotics, may allow those organisms intrinsically resistant to these drugs to be involved more frequently in nosocomial infections. Imipenem was introduced to the specialized hospital units in Kuwait in October, 1992 and meropenem in late 1996. The main objective of this study was to observe prospectively whether, under similar laboratory conditions for microbial isolation/identification while these drugs are in use in the hospital, there is any proportional increase over time in the recovery of Stenotrophomonas maltophilia in relation to the number of yearly admissions and drug use. In addition, we also looked for categories of patients infected by S. maltophilia, type of infection and antibiotic susceptibility. There was an increase in the number of S. maltophilia isolates from 1993 to 1997 significantly correlated with the increase in year-wise consumption of carbapenems (p<0.004). No correlation was observed between yearly number of admissions and both the consumption of carbapenems (p>0.51) and isolation of the organism (p>0.59). Most isolates were from cancer, burns and cardiac patients. The commonest types of infection were wound and septicemia. The organisms were susceptible mostly to ciprofloxacin and co-trimoxazole. The study thus indicates that carbapenem use in a hospital environment may result in emergence of nosocomial infections due to multiresistant S. maltophilia in high risk patients with very limited choice of antibiotics for therapy.