Sophisticated genetic fingerprinting confirmed that a laboratory experiment was the source of a bacterial infection that sickened a graduate student on Boston University’s medical campus, city disease investigators said yesterday.

The genetic tests, conducted at the state laboratory in Jamaica Plain, compared a blood sample from the researcher with bacterial matter recovered from the lab where he was working on BU’s South End campus. “The bottom line,’’ said Dr. Anita Barry, top disease tracker at the Boston Public Health Commission, “is they matched.’’

The analysis erased any doubt about what caused the researcher to become sick last month and intensified investigations into precisely how he was exposed to a germ known as Neisseria meningitidis, which can cause meningitis.

The city’s biological lab safety division will review safety procedures in BU’s medical labs, to ensure that the school is doing everything possible to minimize researchers’ exposure to pathogens, Barry said. Investigators will examine what kind of protective gear the researcher was wearing, what kind of training he received, and how thoroughly he was supervised, Barry said.

The city strengthened its regulation of labs after three BU scientists became infected with tularemia in 2004, an episode that revealed sloppy lab practices and a failure to report those illnesses in a timely fashion.

This time, the university has pledged to operate transparently, promising to share findings of an internal investigation with scientists across the university and even researchers at other schools.

“We want others to learn if there are ways we identify that this could be prevented,’’ said Ara Tahmassian, associate vice president for research compliance at Boston University School of Medicine.

“When I look at this incident, it’s one too many,’’ said Tahmassian, who joined BU after the tularemia cases. “But if some of the other institutions can utilize what went wrong and hear the lessons learned, fantastic.’’

Tahmassian has convened a panel of specialists to review the incident and said he expects them to report expeditiously. “This is not going to be months,’’ he said. “This is going to be within a week or two, pinpointing the best we can.’’

The infection of the researcher, who has recovered, came at an awkward moment for BU. A federal health agency is conducting what is probably the final safety review of a controversial $200 million lab project the university has built to work with the world’s deadliest agents, including Ebola and plague. The centerpiece of that project, a high-security Biosafety Level-4 lab, is in a completed but unoccupied building on Albany Street.

The exposure of the graduate student - the university has not identified him, citing patient confidentiality rules - happened in a building next door to the contentious project. He was participating in the hunt for a vaccine against the form of meningitis caused by the germ.

The researcher was working in a Biosafety Level-2 lab, which has less stringent safety procedures than Level-4 labs. When he became ill, the graduate student sought medical attention and notified the director of the lab, concerned that his symptoms might be related to his research.

Unlike with the tularemia infections, BU alerted city disease investigators of their suspicions about the student within hours of learning about his illness. He is the only person who has become sick, Barry said.

Stephen Smith can be reached at stsmith@globe.com.

© Copyright 2009 Globe Newspaper Company.