Routine screening of harmful microorganisms in beach sands: implications to public health.

Beaches worldwide provide recreational opportunities to hundreds of millions of people and serve as important components of coastal economies. Beach water is often monitored for microbiological quality to detect the presence of indicators of human sewage contamination so as to prevent public health outbreaks associated with water contact. However, growing evidence suggests that beach sand can harbor microbes harmful to human health, often in concentrations greater than the beach water. Currently, there are no standards for monitoring, sampling, analyzing, or managing beach sand quality. In addition to indicator microbes, growing evidence has identified pathogenic bacteria, viruses, and fungi in a variety of beach sands worldwide. The public health threat associated with these populations through direct and indirect contact is unknown because so little research has been conducted relating to health outcomes associated with sand quality. In this manuscript, we present the consensus findings of a workshop of experts convened in Lisbon, Portugal to discuss the current state of knowledge on beach sand microbiological quality and to develop suggestions for standardizing the evaluation of sand at coastal beaches. The expert group at the "Microareias 2012" workshop recommends that 1) beach sand should be screened for a variety of pathogens harmful to human health, and sand monitoring should then be initiated alongside regular water monitoring; 2) sampling and analysis protocols should be standardized to allow proper comparisons among beach locations; and 3) further studies are needed to estimate human health risk with exposure to contaminated beach sand. Much of the manuscript is focused on research specific to Portugal, but similar results have been found elsewhere, and the findings have worldwide implications.

Cladophora in the Great Lakes: impacts on beach water quality and human health.

Cladophora in the Great Lakes grows rapidly during the warm summer months, detaches, and becomes free-floating mats as a result of environmental conditions, eventually becoming stranded on recreational beaches. Cladophora provides protection and nutrients, which allow enteric bacteria such as Escherichia coli, enterococci, Shigella, Campylobacter, and Salmonella to persist and potentially regrow in the presence of the algae. As a result of wind and wave action, these microorganisms can detach and be released to surrounding waters and can influence water quality. Enteric bacterial pathogens have been detected in Cladophora mats; E. coli and enterococci may populate to become part of the naturalized microbiota in Cladophora; the high densities of these bacteria may affect water quality, resulting in unnecessary beach closures. The continued use of traditional fecal indicators at beaches with Cladophora presence is inadequate at accurately predicting the presence of fecal contamination. This paper offers a substantial review of available literature to improve the knowledge of Cladophora impacts on water quality, recreational water monitoring, fecal indicator bacteria and microorganisms, and public health and policy.

Pilot- and bench-scale testing of faecal indicator bacteria survival in marine beach sand near point sources.

AIM: Factors affecting faecal indicator bacteria (FIB) and pathogen survival/persistence in sand remain largely unstudied. This work elucidates how biological and physical factors affect die-off in beach sand following sewage spills. METHODS AND RESULTS: Solar disinfection with mechanical mixing was pilot-tested as a disinfection procedure after a large sewage spill in Los Angeles. Effects of solar exposure, mechanical mixing, predation and/or competition, season, and moisture were tested at bench scale. First-order decay constants for Escherichia coli ranged between -0.23 and -1.02 per day, and for enterococci between -0.5 and -1.0 per day. Desiccation was a dominant factor for E. coli but not enterococci inactivation. Effects of season were investigated through a comparison of experimental results from winter, spring, and fall. CONCLUSIONS: Moisture was the dominant factor controlling E. coli inactivation kinetics. Initial microbial community and sand temperature were also important factors. Mechanical mixing, common in beach grooming, did not consistently reduce bacterial levels. SIGNIFICANCE AND IMPACT OF THE STUDY: Inactivation rates are mainly dependent on moisture and high sand temperature. Chlorination was an effective disinfection treatment in sand microcosms inoculated with raw influent.

Abundance and characteristics of the recreational water quality indicator bacteria Escherichia coli and enterococci in gull faeces.

AIMS: To evaluate the numbers and selected phenotypic and genotypic characteristics of the faecal indicator bacteria Escherichia coli and enterococci in gull faeces at representative Great Lakes swimming beaches in the United States. METHODS AND RESULTS: E. coli and enterococci were enumerated in gull faeces by membrane filtration. E. coli genotypes (rep-PCR genomic profiles) and E. coli (Vitek GNI+) and enterococci (API rapid ID 32 Strep and resistance to streptomycin, gentamicin, vancomycin, tetracycline and ampicillin) phenotypes were determined for isolates obtained from gull faeces both early and late in the swimming season. Identical E. coli genotypes were obtained only from single gull faecal samples but most faecal samples yielded more than one genotype (median of eight genotypes for samples with 10 isolates). E. coli isolates from the same site that clustered at >/=85% similarity were from the same sampling date and shared phenotypic characteristics, and at this similarity level there was population overlap between the two geographically isolated beach sites. Enterococcus API(R) profiles varied with sampling date. Gull enterococci displayed wide variation in antibiotic resistance patterns, and high-level resistance to some antibiotics. CONCLUSIONS: Gull faeces could be a major contributor of E. coli (10(5)-10(9) CFU g(-1)) and enterococci (10(4)-10(8) CFU g(-)1) to Great Lakes recreational waters. E. coli and enterococci in gull faeces are highly variable with respect to their genotypic and phenotypic characteristics and may exhibit temporal or geographic trends in these features. SIGNIFICANCE AND IMPACT OF THE STUDY: The high degree of variation in genotypic or phenotypic characteristics of E. coli or enterococci populations within gull hosts will require extensive sampling for adequate characterization, and will influence methods that use these characteristics to determine faecal contamination sources for recreational waters.

The pediatrician's approach to the preschool child with language delay.

A systematic approach to the child with suspected language disorder includes screening of expressive language, receptive language, general development, and hearing. Various screening approaches and tools are discussed. Diagnostic categories and associated referral patterns are recommended.

X-ray microradiographs of laser fusion targets: improved image analysis techniques.

Improved techniques for analyzing x-ray microradiographic images of laser fusion targets are described. A fast Fourier transform (FFT) technique is used to detect efficiently inner-outer wall nonconcentricities of +/-95 A in hollow glass shells having a mean wall thickness of 1 microm. An improved technique for detecting and quantifying local wall-thickness variations is described. These results are compared with previous sensitivities.

Microradiographs of laser fusion targets: 2-D modeling and analysis.

A new contact microradiographic system for analyzing laser fusion targets with 2-D modeling and image analysis techniques is described. This system, which uses a monochromatic x-ray source and Kodak highresolution plate emulsion, is sensitive to spherical wall thickness variations (eccentricities) as small as +/-200 A in hollow shells with a mean wall thickness of 1 microm. Measurements of wall thickness and of local and spherical wall thickness variations by radiographic techniques, using 2-D video, digital image analysis, and optical interferometry, are compared.

Acoustic hologram formation with a frequency shifted reference beam.

This paper discusses an interference technique that makes it possible to directly observe and record the usually very weak light diffracted by an acoustical surface perturbation. This is accomplished by using spatial filtering techniques in combination with a frequency shifted reference beam. It is shown that the acoustically diffracted light may be visualized even in the presence of statically scattered light of much higher intensity. An experiment is described in which this technique is used to view the surface perturbations of piezoelectric ceramic material caused by acoustic surface waves. The application of this system to acoustic holography is discussed in detail. This application makes use of the fact that bulk acoustic waves in a material, upon striking the surface at some acute angle, cause surface ripple patterns which form a dynamic hologram of the acoustic field. A photographic image of this hologram frozen in time may then be recorded using the process discussed above.

Probing of acoustic surface perturbations by coherent light.

The need for sensitive methods of detection and visualization of acoustic surface perturbations has grown with the increasing interest in such fields as acoustic holography, ultrasonic surface wave devices, and acoustic trapped energy resonators. One very sensitive detection method utilizes a coherent light beam as a probe for locally measuring phase and amplitude of the acoustic field. Several variants of this technique are possible, based on measuring phase, deflection, wave front curvature, and spatial frequency content of the reflected beam. Each one of these variants may be combined with a scanning motion of the beam in order to visualize the entire sound field. This paper will attempt to survey the present state of the art and compare the different techniques on the basis of their sensitivity and applicability to specific requirements.

Visualization of a coherent light field by heterodyning with a scanning laser beam.

This paper discusses a sampling method of optical holography in which the received phase and amplitude information about any arbitrary cross section of a light field is electronically processed and displayed on a TV monitor. Because the technique makes it possible to discriminate between optical signals with a small frequency difference it should be a useful tool in those methods which investigate acoustic phenomena by dynamic scattering of light. In particular, the application to real time acoustic holography is discussed. Experimental results are presented showing the intensity distribution of both statistically and dynamically scattered optical fields.