diff --git a/src/impl/getusername.cpp b/src/impl/getusername.cpp
index 6f11b516ae..35c034fb9d 100644
--- a/src/impl/getusername.cpp
+++ b/src/impl/getusername.cpp
@@ -7,11 +7,6 @@
 #include <vector>
 #include <scxcorelib/scxstrencodingconv.h>
 
-using std::string;
-using std::vector;
-
-using SCXCoreLib::Utf8ToUtf16le;
-
 // https://msdn.microsoft.com/en-us/library/windows/desktop/ms724432(v=vs.85).aspx
 // Sets errno to:
 //     ERROR_INVALID_PARAMETER - parameter is not valid
@@ -79,9 +74,9 @@ BOOL GetUserName(WCHAR_T *lpBuffer, LPDWORD lpnSize)
 	}
 
 	// Convert to char * to WCHAR_T * (UTF-8 to UTF-16 LE w/o BOM)
-	string input = string(userName);
-	vector<unsigned char> output;
-	Utf8ToUtf16le(input, output);
+	std::string input(userName);
+	std::vector<unsigned char> output;
+	SCXCoreLib::Utf8ToUtf16le(input, output);
 
 	if (output.size()/2 + 1 > *lpnSize) {
 		errno = ERROR_INSUFFICIENT_BUFFER;
diff --git a/src/tests/test-getusername.cpp b/src/tests/test-getusername.cpp
index 825e949608..c7bbc14b47 100644
--- a/src/tests/test-getusername.cpp
+++ b/src/tests/test-getusername.cpp
@@ -5,10 +5,6 @@
 #include <scxcorelib/scxstrencodingconv.h>
 #include "getusername.h"
 
-using std::string;
-using std::vector;
-using SCXCoreLib::Utf16leToUtf8;
-
 TEST(GetUserName,simple)
 {
 	// allocate a WCHAR_T buffer to receive username
@@ -21,7 +17,7 @@ TEST(GetUserName,simple)
 	ASSERT_EQ(1, result);
 
 	// get expected username
-	string username = string(getlogin());
+	std::string username(getlogin());
 
 	// GetUserName sets lpnSize to length of username including null
 	ASSERT_EQ(username.size()+1, lpnSize);
@@ -30,10 +26,10 @@ TEST(GetUserName,simple)
 	unsigned char *begin = reinterpret_cast<unsigned char *>(&lpBuffer[0]);
 	// -1 to skip null; *2 because UTF-16 encodes two bytes per character
 	unsigned char *end = begin + (lpnSize-1)*2;
-	vector<unsigned char> input(begin, end);
+	std::vector<unsigned char> input(begin, end);
 	// convert to UTF-8 for assertion
-	string output;
-	Utf16leToUtf8(input, output);
+	std::string output;
+	SCXCoreLib::Utf16leToUtf8(input, output);
 
 	EXPECT_EQ(username, output);
 }