This massive outbreak of watery diarrhea was caused by cryptosporidium oocysts that passed through the filtration system of one of the city's water-treatment plants. Water-quality standards and the testing of patients for cryptosporidium were not adequate to detect this outbreak.

Acute diarrheal disease (ADD) can be caused by a range of pathogens, including bacteria, viruses, and parasites. Conventional diagnostic methods, such as culture, microscopy, biochemical assays, and enzyme-linked immunosorbent assays (ELISA), are laborious and time-consuming and lack sensitivity. Combined, the array of tests performed on a single specimen can increase the turnaround time (TAT) significantly. We validated a 19plex laboratory-developed gastrointestinal pathogen panel (GPP) using Luminex xTAG analyte-specific reagents (ASRs) to simultaneously screen directly in fecal specimens for diarrhea-causing pathogens, including bacteria (Campylobacter jejuni, Salmonella spp., Shigella spp., enterotoxigenic Escherichia coli [ETEC], Shiga toxin-producing E. coli [STEC], E. coli O157:H7, Vibrio cholerae, Yersinia enterocolitica, and toxigenic Clostridium difficile), parasites (Giardia lamblia, Cryptosporidium spp., and Entamoeba histolytica), and viruses (norovirus GI and GII, adenovirus 40/41, and rotavirus A). Performance characteristics of GPP ASRs were determined using 48 reference isolates and 254 clinical specimens. Stool specimens from individuals with diarrhea were tested for pathogens using conventional and molecular methods. Using the predictive methods as standards, the sensitivities of the GPP ASRs were 100% for adenovirus 40/41, norovirus, rotavirus A, Vibrio cholerae, Yersinia enterocolitica, Entamoeba histolytica, Cryptosporidium spp., and E. coli O157:H7; 95% for Giardia lamblia; 94% for ETEC and STEC; 93% for Shigella spp.; 92% for Salmonella spp.; 91% for C. difficile A/B toxins; and 90% for Campylobacter jejuni. The overall comparative performance of the GPP ASRs with conventional methods in clinical samples was 94.5% (range, 90% to 97%), with 99% (99.0% to 99.9%) specificity. Implementation of the GPP ASRs enables our public health laboratory to offer highly sensitive and specific screening and identification of the major ADD-causing pathogens.

A major gastroenteritis outbreak among >400,000 residents of Milwaukee, Wisconsin, in April 1993 was attributed to Cryptosporidium parvum oocysts in drinking water. Plasma specimens obtained from children (6 months to 12 years old) for routine blood lead level surveillance March-May 1993 were assayed by ELISA for levels of IgG antibody against the immunodominant Triton-17 and 27-kDa C. parvum antigens. Over a 5-week period, the seroprevalence for antibodies to the 2 antigens increased from 15% to 82% and from 17% to 87%, respectively, in samples from children living in southern ZIP code areas (n=218), whereas smaller increases (20% to 43% and 22% to 46%, respectively) were noted among samples from children living in northern ZIP code areas (n=335; P<.0001). The results demonstrate that C. parvum infection was much more widespread than previously appreciated and confirm that infection was associated with residence in the area served by the southern water treatment plant.

OBJECTIVETo evaluate and compare the performance of several different methods available for detection of Chlamydia trachomatis (Ct) infection, and to explore possible testing and treatment strategies incorporating point-of-care testing versus laboratory-based tests. RESULTSPerforming a rapid in-clinic test on women who did not meet empiric treatment criteria would have increased the overall proportion of infected persons receiving same-day treatment from 48.6% to 79.1% using DFA or 78.4% using OIA. CONCLUSIONSUse of empiric treatment criteria and same-day point-of-care testing for patients not meeting the empiric treatment threshold appears to be an appropriate, useful, and cost-effective strategy for increasing same-day treatment of Ct infections in this population.

SUMMARYDrug-resistant Mycobacterium tuberculosis bacterium (MTB) is spreading worldwide. Three drug-resistant isolates were detected in Burmese, Hmong, and Indian immigrants currently residing in Milwaukee, Wisconsin, USA. Ion Torrent full-gene sequencing and complete genetic analysis was performed within 5 days and compared to results from traditional drug sensitivity testing (DST). Genetic characterization of seven, full-length resistance-associated genes revealed two MDR and one highly resistant strain with important drug-resistant mutations that were confirmed by traditional DST. The rapid turnaround from sample-to-sequence underscores the public health value of Ion Torrent full-gene sequencing of MDR/XDR genes from epidemiologically significant clinical isolates.