PURPOSE: Strength of association of colonization of various body sites with development of HAI is not well studied. This study was aimed to determine risk of colonization by pathogens and its correlation with development of HAI in critically ill.
METHODS: This prospective study was conducted in critically ill patients in Medical ICU. Patients admitted elsewhere in last one month were excluded. Samples were obtained from axilla, nostrils, perineum, throat, aspirate of endotracheal and Ryle’s tube, and urine within 12 hours of admission, then at 48 hours, day 5 and weakly thereafter. Semi-quantitative cultures were done. The cultures were repeated in the event of HAI.
RESULTS: 50 patients (M:F 33:17;mean age 45±17.9 years) were studies. 49 patients were on mechanical ventilation and 19 were on vasopressors. The mean duration of mechanical ventilation was 10.04 (range2-30) days and hospitalization was 16.44 (range 5-32) days. All patients developed colonization of anterior nares, axilla and perineum. 76% patients developed gastric colonization and 84% developed airway colonization. Cultures from the catheters were sterile. The predominant colonizer of anterior nares and skin was Staphylococcus aureus. Gram negative bacilli (GNB) were most common isolates from the perineum (E.coli), airways (P.aeruginosa) and stomach (E.coli). Staphylococcus aureus (48%) was early (<5 days) colonizer and GNB were late (>5 days) colonizers. 63% of Staph. aureus isolates were MRSA and 99.78% GNBs were ESBL producers. Risk factors for colonization of airway and stomach were duration of stay [(OR) = 1.573 (95% CI 1.128-2.194)], hypo-albuminaemia[OR - 0.018 (95% CI - 0.001-0.445)], higher APACHE-II (p=0.015)and SAPS-II(p=0.041) scores and corticosteroids(p=0.007). 12% patients developed HAI (5 pneumonia and 1 BSI). Microorganism causing airways and gastric colonization and pneumonia were same (P.aeruginosa) in 4 cases. Risk of HAI was associated with a higher APACHE II (p = 0.002) and SAPS II scores (68 v/s 37; p=0.001) and a hypo-albuminemia (p =0.013).
CONCLUSIONS: Severity of illness and low serum albumin are risk factors for colonization. Routine cultures are not necessary and may indeed mislead the clinician.
CLINICAL IMPLICATIONS: Routine surveillance sampling is little use in critical ill patients.
DISCLOSURE: The following authors have nothing to disclose: Gopi Khilnani, Veligalla Mouli, Seema Sood, Vijay Hadda, Arti Kapil, Surender Sharma, Rita Sood
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