Repeated Chlamydia trachomatis infections are associated with lower bacterial loads.

Chlamydia trachomatis (CT) infections remain highly prevalent. CT reinfection occurs frequently within months after treatment, likely contributing to sustaining the high CT infection prevalence. Sparse studies have suggested CT reinfection is associated with a lower organism load, but it is unclear whether CT load at the time of treatment influences CT reinfection risk. In this study, women presenting for treatment of a positive CT screening test were enrolled, treated and returned for 3- and 6-month follow-up visits. CT organism loads were quantified at each visit. We evaluated for an association of CT bacterial load at initial infection with reinfection risk and investigated factors influencing the CT load at baseline and follow-up in those with CT reinfection. We found no association of initial CT load with reinfection risk. We found a significant decrease in the median log10 CT load from baseline to follow-up in those with reinfection (5.6 CT/ml vs. 4.5 CT/ml; P = 0.015). Upon stratification of reinfected subjects based upon presence or absence of a history of CT infections prior to their infection at the baseline visit, we found a significant decline in the CT load from baseline to follow-up (5.7 CT/ml vs. 4.3 CT/ml; P = 0.021) exclusively in patients with a history of CT infections prior to our study. Our findings suggest repeated CT infections may lead to possible development of partial immunity against CT.

Eight years of Legionnaires' disease transmission in travellers to a condominium complex in Las Vegas, Nevada.

Travel is a risk factor for Legionnaires' disease. In 2008, two cases were reported in condominium guests where we investigated a 2001 outbreak. We reinvestigated to identify additional cases and determine whether ongoing transmission resulted from persistent colonization of potable water. Exposures were assessed by matched case-control analyses (2001) and case-series interviews (2008). We sampled potable water and other water sources. Isolates were compared using sequence-based typing. From 2001 to 2008, 35 cases were identified. Confirmed cases reported after the cluster in 2001-2002 were initially considered sporadic, but retrospective case-finding identified five additional cases. Cases were more likely than controls to stay in tower 2 of the condominium [matched odds ratio (mOR) 6·1, 95% confidence interval (CI) 1·6-22·9]; transmission was associated with showering duration (mOR 23·0, 95% CI 1·4-384). We characterized a clinical isolate as sequence type 35 (ST35) and detected ST35 in samples of tower 2's potable water in 2001, 2002, and 2008. This prolonged outbreak illustrates the importance of striving for permanent Legionella eradication from potable water.

Evaluation of the impact of direct plating, broth enrichment, and specimen source on recovery and diversity of methicillin-resistant Staphylococcus aureus isolates among HIV-infected outpatients.

We compared recovery of Staphylococcus aureus and methicillin-resistant S. aureus (MRSA) from nasal and groin swab specimens of 600 HIV-infected outpatients by selective and nonselective direct plating and broth enrichment. Swabs were collected at baseline, 6-month, and 12-month visits and cultured by direct plating to mannitol salt agar (MSA) and CHROMagar MRSA (CM) and overnight broth enrichment with subculture to MSA (broth). MRSA isolates were characterized by pulsed-field gel electrophoresis (PFGE), staphylococcal cassette chromosome mec (SCCmec) typing, and PCR for the Panton-Valentine leukocidin. At each visit, 13 to 15% of patients were colonized with MRSA and 30 to 33% were colonized with methicillin-susceptible S. aureus (MSSA). Broth, CM, and MSA detected 95%, 82%, and 76% of MRSA-positive specimens, respectively. MRSA recovery was significantly higher from broth than CM (P ≤ 0.001) or MSA (P ≤ 0.001); there was no significant difference in recovery between MSA and CM. MSSA recovery also increased significantly when using broth than when using MSA (P ≤ 0.001). Among specimens collected from the groin, broth, CM, and MSA detected 88%, 54%, and 49% of the MRSA-positive isolates, respectively. Broth enrichment had a greater impact on recovery of MRSA from the groin than from the nose compared to both CM (P ≤ 0.001) and MSA (P ≤ 0.001). Overall, 19% of MRSA-colonized patients would have been missed with nasal swab specimen culture only. USA500/Iberian and USA300 were the most common MRSA strains recovered, and USA300 was more likely than other strain types to be recovered from the groin than from the nose (P = 0.05).

Methicillin-resistant Staphylococcus aureus colonization in HIV-infected outpatients is common and detection is enhanced by groin culture.

SUMMARYAlthough high rates of clinical infection with methicillin-resistant Staphylococcus aureus (MRSA) have been reported in HIV-infected adults, data on MRSA colonization are limited. We enrolled HIV-infected adults receiving care at the Atlanta VA Medical Center. Swabs from each participant's nares and groin were cultured with broth enrichment for S. aureus. Of 600 HIV-infected adults, 79 (13%) were colonized with MRSA and 180 (30%) with methicillin-susceptible S. aureus. MRSA pulsed-field gel electrophoresis types USA300 (n=44, 54%) and USA500/Iberian (n=29, 35%) predominated. Inclusion of groin swabs increased MRSA detection by 24% and USA300 detection by 38%. In multivariate analysis, MRSA colonization compared to no MRSA colonization was associated with a history of MRSA clinical infection, rarely or never using condoms, and contact with prisons and jails. In summary, the prevalence of MRSA colonization was high in this study of HIV-infected adults and detection of USA300 was enhanced by groin culture.

Methicillin-resistant Staphylococcus aureus infections among healthy full-term newborns.

OBJECTIVE: Methicillin-resistant Staphylococcus aureus (MRSA) strains have emerged in the community, causing disease among healthy people lacking traditional risk factors for MRSA infection. This article describes an outbreak of MRSA among healthy full-term newborns. DESIGN: Cases were identified and corresponding medical information collected. Telephone interviews were conducted with mothers of cases and surveillance cultures from mothers and newborns were performed. MRSA isolates were genotyped. SETTING: Hospital in Chicago, Illinois, USA. PARTICIPANTS: Newborns, their mothers and hospital healthcare workers. INTERVENTION: Nursery infection control practices were enhanced. The MRSA-colonised healthcare workers received intranasal mupirocin. MAIN OUTCOME: Within 4-23 days of birth, 11 newborns were identified with pustules, vesicles or blisters located on the head, groin, perineum, ears, legs, chin and trunk. All received antimicrobials and recovered without incident. RESULTS: None of 432 peripartum women, one of 399 newborns, and two of 135 healthcare workers were nasal MRSA carriers. Available isolates from six patients, two healthcare workers, and one from an MRSA-colonised newborn were similar by pulsed-field gel electrophoresis. Other than contact with the hospital, no common exposures of MRSA transmission were identified. CONCLUSIONS: MRSA strains that initially emerged in the community are now causing disease in healthcare settings. Providers should be aware that MRSA can cause skin infections among healthy newborns. Adherence to standard infection control practices is important to prevent transmission of MRSA in nurseries.

Trends in fatal firearm-related injuries, United States, 1962-1993.

OBJECTIVE: Our objective was to review historical trends in U.S. fatal firearm-related injuries for the years 1962-1993. METHODS: Using mortality data from the National Center for Health Statistics and population estimates projected from census data, we calculated national age-adjusted mortality rates and examined trends over the 32-year period. Data were also examined by type of firearm-related death (unintentional, suicide, homicide, legal intervention, and undetermined intention), race, gender, and age group. RESULTS: During the 32-year period, the total number of firearm-related deaths increased by 137%, from 16,720 in 1962 to 39,595 in 1993. Suicide and homicide were responsible for most firearm fatalities. Rates for both firearm suicides and firearm homicides increased over time, while rates for unintentional, legal intervention, and undetermined intention decreased. The highest rates and widest variation in total firearm-related mortality occurred among African-American men (35.2/100,000 to 84.5/100,000). Persons 15-19, 20-24, and > or = 75 years of age experienced the largest changes in rates during recent years; total firearm mortality was higher for the younger age groups (15-19, 20-24) during 1990 through 1993 than any other time during the 32-year period. CONCLUSIONS: These surveillance data help characterize trends over time and the magnitude of firearm-related mortality and identify groups at risk. However, further efforts to improve our understanding of firearm-related deaths and injuries, such as expansion of current surveillance to include information about morbidity associated with firearms and additional epidemiologic research to identify modifiable individual and societal risk factors, are necessary.

Sentinel surveillance for antimicrobial resistance in Neisseria gonorrhoeae--United States, 1988-1991. The Gonococcal Isolate Surveillance Project Study Group.

PROBLEM/CONDITION: The prevalence of antimicrobial resistance in Neisseria gonorrhoeae in the United States has been increasing since the mid-1970s. DESCRIPTION OF SYSTEM: The Gonococcal Isolate Surveillance Project (GISP) was established in 1986 to monitor trends of antimicrobial resistance in N. gonorrhoeae. GISP is a sentinel surveillance system consisting of 26 publicly funded sexually transmitted disease clinics and five regional laboratories. At each clinic, urethral isolates are obtained from the first 20 men diagnosed with gonorrhea each month; these isolates are shipped to one of the regional laboratories, where the susceptibilities of the organisms to a panel of antibiotics are determined. REPORTING PERIOD COVERED: This report describes the results of surveillance for antimicrobial resistance in N. gonorrhoeae from January 1991 through December 1991. These results are compared with data obtained from January 1988 through December 1990. RESULTS AND INTERPRETATION: In the 1991 GISP sample, 32.4% of isolates were resistant to penicillin or tetracycline. The proportions of isolates with high-level, plasmid-mediated resistance to penicillin, tetracycline, or both drugs have increased significantly (p < 0.001) in the GISP sample during 1988-1991. No documented clinical treatment failures have been related to decreased susceptibility of N. gonorrhoeae to either ceftriaxone or ciprofloxacin, which belong to the classes of antibiotics currently recommended for gonococcal therapy. ACTION TAKEN: Because of the demonstrated ability of N. gonorrhoeae to develop resistance to antimicrobial agents, surveillance to guide therapy recommendations will be continued.