Updates
Update
So, the Condom Broke?
Source: Steiner MJ, et al. Sex Transm Dis 1999;26:459-462.
While studies have shown that 90% of sexually active adults understand that condoms are the cornerstone of safe sex, their use remains woefully inadequate. Condoms are simply not used for at least 70% of sex acts among couples at risk for STDs. However, some experts argue that condom "failure" due to slippage or breakage may be responsible for the continued transmission of STDs in couples at risk.
In an editorial contradicting this assertion, Steiner and colleagues pondered the "global risk" of inadequate condom use compared with the possible ways in which condoms may "fail" the user. Explanations for condom failure during use included condom breakage or slippage, failure to use the condom during the entire sex act, and failure of the condom to form an effective barrier against transmission of STDs. Based on extensive permeability studies, the latter is not likely for latex condoms. The risk of transmission of HIV, for example, is about 10,000-fold less with a latex condom than without. On the other hand, estimates of condom breakage during sex vary from 0-6.7% of coital acts (average 2%) and condom slippage occurs in 0.6-5.4% of sex acts. Failure to use a condom during the entire sex act is estimated to occur about 10% of the time, and has been associated with the transmission of gonorrhea in one study.
While 7.5 billion condoms are used annually worldwide, an estimated 16.5 billion additional high-risk sex acts remain unprotected per year. Based on the above figures, condom breakage may occur in ~225 million at-risk coital acts, a figure which is trivial in comparison to the total number of unprotected sex acts. While improper use of condoms or condom failure may account for ~1% of the continued transmission of HIV and other STDs, nonuse is by far the larger issue. Promoting condom use and making condoms readily available, for example, in high schools, college campuses, and the work place, is essential.
More on Pig Ears and Salmonella
Since canadian health authori-ties reported 16 human cases of Salmonella infantis infection in the Provence of Alberta associated with handling pig ear treats for dogs, the California Department of Health Services and the CDC have begun an investigation of possible similar cases in California. A total of 23 S. infantis infections have been reported in California since June 1, 1999; thus far, three patients reported contact with pig’s ear dog treats. Preliminary laboratory tests uncovered evidence of colonization of leftover dog treats with S. typhimurium v. copenhagen. Although this strain differs from that involved in the Alberta outbreak, it does suggest a problem with contamination of these products with pathogenic Salmonella.
More on Pigs and Resistant Salmonella
Source: Molbak K, et al. N Engl J Med 1999;341:1420-1425.
Molbak and colleagues tracked the spread of a novel, highly resistant strain of Salmonella typhimurium (DT104) from slaughterhouse pigs to 27 humans in Denmark. DT104 is uniquely resistant to five drugs, including nalidixic acid and, possibly, fluoroquinolones. Denmark has established a vigorous surveillance system of farm animals for Salmonella. The outbreak was, therefore, quickly recognized in June 1998 when this unusually resistant Salmonella was isolated from five patients and, at the same time, health inspectors isolated the same strain from a sample of pork from a slaughterhouse, as well as surveillance samples taken from two wholesale dealers who received their meat from the slaughterhouse. Further investigation of nearly 90 herds revealed that two herds had been infected—fluoroquinolones had been used in both.
The outbreak continued through August 1998, during which 27 human cases were identified. Twelve patients required hospitalization and two patients died of complications of intestinal perfor-ation. The incubation period ranged from 4.5 hours (in a patient who taste-tested a raw meatball) to seven days. Occupational exposure resulted in infection in two patients, including a slaughterhouse employee and a nurse who cared for an infected patient. A third patient shared a hospital room with an infected patient. Of those for whom data on food exposure was available, 18 of 19 had consumed pork products, nine of which could be traced to pork supplied by the slaughterhouse.
Several patients had no apparent clinical response to ciprofloxacin, although, as determined by tablet diffusion, the isolates appeared sensitive in vitro to cipro-floxacin (MIC 0.064-0.124 mg/L). However, the naladixic acid-resistant isolates were only one-tenth as susceptible to ciprofloxacin as other naladixic acid-sensitive strains. Molecular analysis revealed that all of the isolates from patients and pork contained the same unique amino acid substitution of the gyrA gene, which conferred naladixic acid resistance. This mutation has seldom been detected in humans and never in Denmark. Molbak et al expressed concern that disc or tablet dilution tests may not detect reduced quinolone susceptibility in isolates with a single mutation in the gyrase gene. Decreased susceptibility to fluoroquinolones should be suspected in nalidixic-acid-resistant Salmonella, irrespective of the results of in vitro studies.
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