Although not as common as months past, bed bug infestations continue to plague hotels, lodgings and even hospitals. There are also suggestions that the reason infestations continue are, in part, because bed bugs are developing an immunity to the pesticides previously used.

While pesticide researchers are faced with leveling that playing field, Hospital Infection Control & Prevention asks infection prevention experts, "Can bed bug bites transmit infections?" The standard answer has been "No," with some qualification, even though on any given day the insects may be carrying a wide array of viruses, bacteria, protozoa and parasitic worms.

Research reveals that hepatitis B viral DNA can be detected in bed bugs up to 6 weeks after they feed on infectious blood, but no transmission of hepatitis B infection was found in a study using chimpanzees. With its high titers in the blood, HBV would be one of the prime suspects for transmission, but there have been no documented cases of infection via bedbugs with that virus, nor with the generally less transmissible HCV or HIV.

However, a recent letter to Emerging Infectious Diseases, raises that possibility under certain conditions, bedbugs could serve as a vector for transmission of drug-resistant bacteria like methicillin-resistantStaphylococcus aureus (MRSA) and vancomycin resistant enterococci (VRE).

The authors report that "three patients, all residents of … an impoverished community … with high rates of homelessness, poverty, HIV/AIDS, and injection drug use—were hospitalized and found to be infested with bedbugs."

Hypothesizing that the parasites may be vectors for the transmission of antimicrobial drug–resistant pathogens, they collected 5 bed bugs and tested them for drug-resistant organisms. For 2 patients, VRE was isolated from 1 bed bug each. These bacterial isolates were also resistant to ampicillin, teicoplanin, and aminoglycosides but susceptible to linezolid, quinupristin/dalfopristin, and tetracycline. For 1 other patient, MRSA was isolated from 3 bed bugs. All MRSA isolates had susceptibility patterns consistent with pulsed-field gel electrophoresis type USA300 (susceptible to vancomycin, clindamycin, trimethoprim/sulfamethoxasole, tetracycline, and rifampin; resistant to erythromycin).

Thickening the plot, the authors note that irritation at the site of the bites can cause further skin abrasion, thereby providing an entry point for colonizing bacteria. S. aureus, which is commonly found on the skin and can cause cellulitis, has been reported to colonize the salivary glands of bed bugs for as long as 15 days.

"Bedbugs carrying MRSA and/or VRE may have the potential to act as vectors for transmission," the authors note. "…Bedbug carriage of MRSA, and the portal of entry provided through feeding, suggests a plausible potential mechanism for passive transmission of bacteria during a blood meal. Because of the insect’s ability to compromise the skin integrity of its host, and the propensity for S. aureus to invade damaged skin, bedbugs may serve to amplify MRSA infections in impoverished urban communities."

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