With infestations on the rise recently, bedbugs have been quite popular in the news. Bedbug bites are extremely uncomfortable and lead to itchy skin reactions similar to other insect bites, such as mosquito bites. Their notoriety comes both from increasing numbers of hotels, apartments, and retail stores with large infestations and from the difficulty of eradicating these pests.
Bedbugs can withstand a variety of environments including cold and humidity, can survive by feeding as infrequently as once per year, and are often resistant to most standard insecticides used by exterminators. Additionally, they are downright sneaky and all it takes is one of these small critters hitching a ride home from a hotel in your suitcase to start a nightmare of a problem.
While bedbugs feed on human blood, they have not been known to spread blood-borne diseases such as hepatitis and HIV. That’s why a recent article published in the Washington Post (http://www.washingtonpost.com/national/health/bedbugs-may-play-role-in-spread-of-mrsa-under-some-conditions-study-finds/2011/05/11/AFsehKqG_story.html?hpid=z10) entitled "Bedbugs may play role in spread of drug-resistant bacteria MRSA, study finds" caught my attention. MRSA, which stands for methicillin-resistant Staphylococcus aureus, is a type of infection that has also gained media attention. MRSA infections most commonly occur in the skin, and frequently present as abscesses, or painful red lumps that fill with large amounts of pus. In most cases, MRSA is no more serious than many common skin infections and is easily treated with standard antibiotics (although the strains will be resistant to certain types of penicillins). Most concerns over MRSA are due to infections that occur in hospitalized patients, who are typically very ill. These hospital-acquired strains are often resistant to most standard antibiotics and, on top of being difficult to treat, they are occurring in individuals with immune systems weakened by other medical problems. In these cases, MRSA can be fatal. Thus, the possibility of MRSA being spread by bedbugs, as suggested by the article headline, is certainly alarming. But do we really need to be alarmed?
The article in the Washington Post refers to a study published in the journal Emerging Infectious Diseases titled "Bedbugs as vectors for drug-resistant bacteria" (http://www.cdc.gov/eid/content/17/6/1132.htm). In this study, bedbugs found on three hospitalized patients were essentially ground up, and the puree was placed on standard culture plates used to grow common bacteria. This test was performed on a total of five bedbugs, and two grew a type of bacteria called VRE (vancomycin-resistant Enterococcus) while the other three – all from the same patient – grew a strain of MRSA. Based on these results, the study proposes that bedbugs may be capable of spreading different strains of antibiotic-resistant bacteria, including MRSA.
While the findings are certainly interesting, I want to point out that they are neither conclusive nor suggestive that bedbugs can spread these bacteria and cause serious infections. The study does not mention if the same bacteria cultured from the bedbugs were also found on the patients from which the bugs were taken. Therefore, while the evidence suggests that the bedbugs carry these bacteria, there is no way to know if they are capable of transferring them to humans. Secondly, if the bedbugs are able to transfer bacteria to the humans on whom they feed, we cannot tell from this study if it is enough of a bacterial load – that is, if the number of actual bacterial organisms are high enough – to cause an infection. We also do not know where the bedbugs were carrying the bacteria exactly – whether it was on their exterior shells or in their saliva – which would affect their ability to transfer the bacteria. For example, human blood-borne diseases such as hepatitis B and C have been found in the saliva of bedbugs, but bedbugs are not known to be able to infect people with these diseases despite this finding.
Last, it is very important to note that only a total of five bedbugs were studied; we don't really know how many of these pests actually carry bacteria, and the answer could very well be the vast majority do not. My conclusions? While the possibility of bedbugs spreading MRSA infections is frightening, based on this study and the scientific information about bedbugs available, there is no reason at this point to think that this is the case. Only rigorous research and time will tell; until then, I say rest easy, and don't let the bedbugs bite.