By: James Peacock

Oakland County Health Officials have recently been busy investigating a Salmonella outbreak that they have linked to a restaurant in Rochester, Michigan. The specific serotype of Salmonella that caused this outbreak is known as Saintpaul. There are more than 2000 known Salmonella serotypes, and the CDC estimates that Salmonella Saintpaul is the tenth most common serotype. Fifteen people have been sickened in the outbreak, which has been linked to Rojo Mexican Bistro. The Bistro voluntarily closed after it was connected to the outbreak. Dr. Pamela Hackert, Oakland County Health Division Chief of Medical Services, has stated that the location was voluntarily closed by its owners “out of an abundance of caution”, and that “the company has been cooperating with us.” The downtown Rochester location of Rojo Mexican Bistro is the only Rojo location to be affected by the outbreak. The fifteen cases of Salmonella poisoning are not contained only in Oakland County. Other counties in Michigan have reported cases of illness, and even some residents of Ohio and Illinois have been sickened. Health officials have, as the investigation has progressed, noted that some of the illnesses have been caused by contact with ill persons, and not necessarily the consumption of contaminated food. This had led health officials to reiterate the importance of proper handwashing techniques, a staple of infection prevention.

Investigation

As the investigation progresses, more information will become available. The process of investigating an outbreak usually occurs after there is a spike in illnesses. When a random spike in illnesses is detected, health officials can then investigate the outbreak, usually by taking samples and by conducting interviews. There is sometimes a correlation between interview answers, which can help investigators locate a source. Over the course of this outbreak investigation, interviews have pointed towards Rojo Mexican Bistro, but other restaurants were also reported to have been visited by more than one ill individual. Health officials declined to comment on which specific restaurants were named, however. Although interviews can help locate potential sources, the best way for health officials to learn more about an outbreak is through the testing of samples. When medical providers retrieve samples from ill people or from the environment, the samples undergo testing to learn more about them. Many samples were taken from both the food and the environment of the Rojo Mexican Bistro, but none of these samples have tested positive for Salmonella contamination. This has left the source of the outbreak unknown. Again, as the investigation progresses, a source may end up being found. Unfortunately, not all outbreaks end up with a definitive source, as it can sometimes be difficult to narrow down one specific item that caused the investigation. As more testing is done, investigators will be able to further narrow down the source. Salmonella Saintpaul has been connected to quite a few different sources in the past.  In 2008, more than 1400 people were sickened by the same Salmonella Saintpaul strain. In that outbreak, jalapeños, serrano peppers, and tomatoes were all thought to have contributed to the outbreak. Cucumbers were connected to a Salmonella Saintpaul outbreak in 2013 in an outbreak that sickened 84 people. A Salmonella Saintpaul outbreak was also linked to alfalfa sprouts in 2009. 235 people were sickened in that outbreak, including 19 cases in Michigan.

Salmonella Infections

Salmonella infections, commonly referred to as Salmonellosis, make up one of the most common forms of foodborne illness in the United States. The CDC estimates that up to 1.2 million cases of Salmonella poisoning occur each year. This estimate includes the fact that many Salmonella cases go unreported and undiagnosed. The tracking of Salmonellosis first took place in 1962, but scientists have been aware of the bacterium for at least 125 years. The work of Dr. Salmon and his assistant, Theobald Smith, allowed for the isolation of Salmonella bacteria just 30 years after the acceptance of germ theory. Since that time, the bacteria that make up the Salmonella genus have been found to have a variety of strains, or serotypes. These serotypes are based on the antigens found on the surface and flagella of the bacteria. At the first usage of this method of categorization, 44 different serotypes had been identified. Today there are more than 2000 known serotypes of Salmonella bacteria, though not all are commonly the source of foodborne illness outbreaks. Salmonella infections are most commonly caused by Salmonella Enteritidis, Typhimurium, Newport, javiana, Heidelberg, I 4,[5], 12:i:-, Muenchen, Montevideo, and Saintpaul.

Out of the CDC estimated 1.2 million annual cases of illness, about 19,000 of them require hospitalization, and about 450 lead to death. While there are actually two distinct types of illness caused by Salmonella bacteria, nontyphoidal salmonellosis and typhoid fever, nontyphoidal salmonellosis is by far the more common type. In fact, there has not been an outbreak connected to typhoid fever caused by Salmonella since 1999. Salmonellosis will generally produce symptoms within a 6 to 72 hour window after exposure to the bacteria. The symptoms produced by salmonellosis will usually include headache, fever, diarrhea, abdominal cramps, nausea, and vomiting. Recovery from a case of Salmonella poisoning will typically start after about a day, but symptoms can last for up to a week. There is a chance that the infection will worsen and cause one of several complications. The most common of these complications is dehydration. Severe dehydration can be very serious, and will often cause hospitalization to be required. Other complications include reactive arthritis and blood poisoning, which are both very serious but much less common. Those with certain risk factors, including the elderly, children, those with HIV/AIDS, and others with suppressed immune systems are at an increased risk of developing a more serious case of Salmonellosis. These risk factors also heighten the chance that one of the complications associated with Salmonella poisoning will occur. Salmonella bacteria can be found in a wide variety of foods and drinks, so it is important to practice proper food safety techniques in order to reduce the chance of infection. If you or a loved one begins to show the symptoms of Salmonella poisoning, contact a medical professional.

Sources:

http://www.detroitnews.com/story/news/local/oakland-county/2017/06/02/oakland-co-investigating-cases-salmonella/102449920/

https://patch.com/michigan/rochester/salmonella-concerns-close-popular-rochester-restaurant

https://www.oakgov.com/health/news/Pages/Health-Division-Investigating-Salmonella-Saintpaul-Infections.aspx

https://www.cdc.gov/salmonella/general/technical.html

https://www.cdc.gov/mmwr/preview/mmwrhtml/mm5734a1.htm

https://www.cdc.gov/salmonella/saintpaul-04-13/

https://www.cdc.gov/salmonella/2009/raw-alfalfa-sprouts-5-8-2009.html