Human immunodeficiency virus-infected patients attending skin outpatient department were studied for nasal carriage of methicillin-resistant Staphylococcus aureus (MRSA) and associated factors affecting nasal colonization. Nasal swabs were used for isolation of S. aureus. MRSA were detected by agar screen and agar dilution methods. Careful examination for dermatoses was carried out. Forty-six of the 60 (76.67%) outpatients with HIV infection were colonized with S. aureus in the anterior nares. Significant number of S. aureus carriers were in the 31-40 year age group. Methicillin resistance was found in eight (17.39%) isolates. Of the 46 S. aureus strains, 29 (63%) were resistant to erythromycin, 69.5% to co-trimoxazole and 41.3% to ciprofloxacin. Co-trimoxazole use was found to be a risk factor for S. aureus carriage ( P = 0.0214) but not for methicillin resistance. Hospital stay for more than 10 days was a risk factor for methicillin resistance whereas stay for more than 25 days was found to be a highly significant risk factor. Dermatophytosis and herpes simplex virus infection were other risk factors for nasal carriage of S. aureus.
Background
Stenotrophomonas maltophilia (SM) is a growing cause of opportunistic nosocomial infections with a mortality rate of 23–77%. Previous studies have identified the use of broad-spectrum antibiotics, specifically carbapenems, as a risk factor for SM infection, but these findings were limited to secondary endpoints. Meropenem’s overall broad-spectrum activity but limited SM activity may favor SM colonization and infection.MethodsAdult patients admitted between January 2016 and July 2018 with available culture data were identified using data mining software. Cases were defined by a positive SM respiratory culture between days 2 and 60 of admission and receipt of antibiotic treatment. Controls were defined by a respiratory culture negative for SM during the same period. The primary endpoint was to evaluate the exposure to at least 48 hours of meropenem between cases and controls, with exposure defined as at least 48 hours of meropenem treatment with the last dose given within 15 days of respiratory culture. Secondary endpoints were to evaluate exposure to at least 7 days of meropenem or other antipseudomonal antibiotics.ResultsA total of 225 patients were included, 106 as cases and 119 as controls. Baseline demographics and age-adjusted Charlson comorbidity index score were similar between groups. Twenty-one cases (19.8%) and 5 controls (4.2%) were exposed to at least 48 hours of meropenem before developing SM pneumonia. The odds of meropenem exposure was 5 times greater in cases than controls (OR = 5.6, P < 0.001). After adjusting for a longer length of stay before culture collection as a potential confounding variable, meropenem use was still associated with SM pneumonia (adjusted OR = 4.6, 95% CI 1.7–14.7). Significant associations were also found with exposure to at least 7 days of meropenem (OR = 4.7, 95% CI 1.52–14.77, P = 0.004) or other antipseudomonal antibiotics (OR = 3.0, 95% CI 1.59–5.71, P < 0.001).ConclusionThis is the first study to evaluate meropenem as a risk factor for developing SM pneumonia. Even as little as 48 hours of meropenem exposure increases the risk of developing SM pneumonia. As one of the few modifiable risk factors for SM infection, judicious use of meropenem may reduce the incidence of SM infection and associated mortality.
Disclosures
All authors: No reported disclosures.
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