Antimicrobial Susceptibilities of Unique Stenotrophomonas maltophilia Clinical Strains

Abstract

Susceptibility to 41 antimicrobials was studied with 99 Stenotrophomonas maltophilia strains, and different pulsed-field gel electrophoresis profiles were identified among 130 prospectively collected isolates. Moxalactam, doxycycline, minocycline, and clinafloxacin displayed the highest activity (>98% susceptibility). Ticarcillin resistance (75%) was reverted by clavulanate in 25% of strains. Trimethoprim-sulfamethoxazole resistance was 26.2% (>4 [trimethoprim]/76 [sulfamethoxazole] g/ml) and dropped to 11.1% when an 8/152-g/ml breakpoint was applied based on its bimodal MIC distribution. Resistance was lower when unique strains were considered, because clonal organisms contribute to resistance.

Combination Antimicrobial Susceptibility Testing of Multidrug-Resistant Stenotrophomonas maltophilia from Cystic Fibrosis Patients

“…Co-trimoxazole is often the drug of first choice for therapy, although increasing in vitro resistance is being reported (2,9,14). Of the patients in our study, 24.2% had co-trimoxazole-resistant S. maltophilia, and, like Valdezate et al, we also found a bimodal distribution of MICs (29). We can draw no firm conclusions regarding trends in susceptibility patterns of individual antimicrobials due to the low numbers of isolates tested on an annual basis (data not shown) and do not know if the referred S. maltophilia were from individuals with transient infection or individuals who were colonized with this organism.…”

“…The high rate of resistance found in this study serves to underline the resistant nature of S. maltophilia present in the Scottish CF population. Co-trimoxazole, ticarcillin/clavulanate, minocycline, doxycycline, levofloxacin, and chloramphenicol have all been reported as being the most active single agent against S. maltophilia isolated from individuals with and without CF (6,9,11,18,22,27,29). Co-trimoxazole is often the drug of first choice for therapy, although increasing in vitro resistance is being reported (2,9,14).…”

“…S. maltophilia is a ubiquitous organism commonly isolated from water, soil, and sewage and also from nosocomial environments. This organism can be the cause of respiratory, urinary, and bloodstream infections in hospitalized patients, especially in those who are immumocompromised or are in intensive care units and particularly in those patients who are catheterized or are receiving mechanical ventilation (22,29). It has recently been shown to be a risk factor for pulmonary exacerbation in CF, but the role it plays in the decline of lung function is unclear (3,11,13,30).…”

Investigation of the Presence of Class 1, 2, 3 Integrons and Their Relationships with Antibiotic Resistance in Clinical Stenotrophomonas maltophilia Isolates

“…S.maltophilia, betalaktamaz, aminoglikozid asetil transferaz ve eritromisini inaktive eden enzim ve atım pompaları kodlayan genleri nedeniyle birçok antibiyotiğe intrensek olarak dirençlidir. Karbapenemler dahil pek çok geniş spektrumlu antibiyotiğe de direnç gösterebildiğin-den, S.maltophilia enfeksiyonlarında tedavi seçenekleri oldukça kısıtlıdır 2 . Bu bakteride, bu mekanizmaların yanında mutasyonla veya türler arasında genetik materyal aktarımı yoluyla da antibakteriyellere direnç gelişmektedir 3 .…”

Antibiotics resistance of Stenotrophomonas maltophilia strains isolated from various clinical specimens

“…maltophilia strains are intrinsically resistant to multiple antibiotics due to aminoglycoside acetyl-transferase and enzymes that inactivate erythromycin and genes encoding efflux pumps 8 . Besides the S. maltophilia strains being resistant to one antibiotic, these strains can develop resistance to multiple antibiotics (multidrug resistance).…”