Description of MRSA small colony variant (SCV) outbreak in an ICU in Rio de Janeiro

Objective

To describe an outbreak of SCV and its epidemiology.

Materials and method

We conducted a retrospective study analyzing nine previously identified cases (two of them out of the ICU) of SCV-related sepsis occurring in the period between November 1998 and September 1999. Clinical and epidemiologic data were collected and compared to patients with MRSA (non-SCV) infection.

Results

We found a higher hospital mortality (100% versus 50%) and ICU mortality (71.5% versus 12.5%) comparing SCV and non-SCV infection, respectively. SCV-infected patients received more antibiotics when compared with the control group (85.7% versus 62.5%). Data such as age (71.8 versus 79.4 years), sex, APACHE II (23 versus 21.8), time of acquisition of MRSA (22.5 versus 27 days) and duration of mechanical ventilation (27.8 versus 24.2 days) did not achieve statistically significant difference.

Conclusion

This is a unique study on this subject in Brazil, and its original data confirm previous description of infections caused by S aureus SCV whose characteristics result from its phenotypical adaptations. A worse prognosis is usually associated with this strain, which are a cause of more persistent, recurrent and resistant infections; in this case an ominous prognosis is worsened by methicillin resistance.