Division of Disease Control and Health Protection

For August 13, 1999

The National Anti-microbial Resistance Monitoring System (NARMS) was established to prospectively monitor the anti-microbial resistance of human non-typhoid Salmonella and E. coli O157:H7 isolates. In 1998 there were 16 health department partners, including Florida, representing approximately 97 million persons (37% of the US population) who provided data and isolates to the program. Seven states also monitored anti-microbial resistance among human Campylobacter isolates.

Here’s how it works: NARMS participating laboratories select every 10^th Salmonella isolate and every 5^th E. coli O157:H7 isolate received at their laboratory and forward these to the CDC for susceptibility testing against 17 anti-microbial agents. Public health labs from 7 states also select and forward the first Campylobacter isolate each week to CDC for susceptibility testing against 8 anti-microbial agents.

CDC tested a total of 1466 Salmonella isolates. The agents with the highest prevalence of resistance were tetracycline (20.1%), sulfamethoxazole (19.3%), streptomycin 18.6%), and ampicillin (16.4%). Among Salmonella isolates, 27.1% were resistant to one or more agents and 23.6% were resistant to two or more agents. Serotype Enteritidis accounted for 16.7% of the isolates and of these, 12.2% were resistant to one or more antimicrobial agents. Serotype Typhimurium accounted for 25.9% of the isolates and of these, 52.6% were resistant to one or more anti-microbial agents.

Among the Typhimurium isolates, 31.6% were resistant to the five anti-microbial agents, ampicillin, chloramphenicol, streptomycin, sulfamethoxazole, and tetracycline (ACSSuT), to which S. Typhimurium DT104 is commonly resistant. A second penta-resistant pattern has emerged among S. Typhimurium – strains that are not DT104 by phage typing. These isolates were resistant to ampicillin, kanamycin, streptomycin, sulfamethoxazole, and tetracycline (AKSSuT). Both the ACSSuT and AKSSuT resistance pattern isolates were often additionally resistant to other anti-microbial agents.

Only one Salmonella isolate was found to be resistant to ciprofloxacin. Both S. Enteritidis and S. Typhimurium serotypes had a percentage that showed reduced susceptibility to ciprofloxacin; the percentage of these isolates increased from 0.4% in 1996 to 0.7% in 1998. The percentage of Salmonella isolates resistant to nalidixic acid increased from 0.4% in 1996 to 1.4% in 1998; both Enteritidis and Typhimurium serotypes were included.

Florida contributed 4.5% (n=66) of the Salmonella isolates in this study. Seven of these were serotype Typhimurium, of which 5 were ACSSuT and 2 were AKSSuT.

Of the 313 isolates tested for anti-microbial sensitivity, 7.3% were found resistant to one or more anti-microbial agents and 6% were resistant to two or more agents. The most common resistance was to sulfamethoxazole (5.8%) or tetracycline (4.5%). None of the isolates tested were resistant to the other anti-microbials tested.

CDC tested 346 isolates of Campylobacter: 96.0% were C. jejuni and 2.6% were C. coli isolates. Among the C. jejuni isolates, 54.5% were resistant to one or more anti-microbial agents and 15.6% resistant to two or more agents. The most common resistance among C. jejuni isolates was to tetracycline (46.4%) followed by naladixic acid (15.1%), and ciprofloxicin (13.3%). Among C. coli isolates, 56.0% were resistant to one or more anti-microbial agents and 33.0% were resistant to two or more agents. The most common resistance among C. coli isolates was to nalidixic acid (55.6%), followed by tetracycline (44.4%), chloramphenicol (22.2%), and ciprofloxacin (11.1%).

Molecular biology is rapidly becoming an essential component of epidemiological investigations of food-borne, nosocomial and community outbreaks. No longer are investigators faced with the question, "are isolates from patient’s A and B the same strain or a different strain of bacteria X." Today molecular biology can answer this question by fingerprinting DNA, the genetic material of all living organisms. Moreover, surveillance fingerprinting has detected sporadic outbreaks thus expanding the role of the public health laboratory to that of initiating investigations through the epidemiology department.

There are several molecular methods currently available to strain-type bacteria. Some methods distinguish strains based on differences or polymorphisms residing at single genetic loci (a gene). These analyses are usually done with the help of the polymerase chain reaction (PCR) or DNA probes. While these methods of strain typing are useful they generally require genus/species-specific reagents and are better suited for the research not clinical laboratory.

The simplest most versatile and discriminating method applicable to virtually all gram positive and negative bacteria is restriction fragment length polymorphism analysis (RFLP). Instead of looking at just one gene, this procedure gives mapping information about the entire genome. Different strains of the same bacteria, (e.g., Salmonella typhi) can have different genomic maps that literally can be seen by molecular analysis.

RFLP analysis of genomic DNA requires an instrument called a pulsed-field gel electrophoresis (PFGE) machine. Suffice it to say, that RFLP/PFGE data yields what amounts to a genetic barcode or DNA fingerprint (see figure). Because myriad studies comparing epidemiological data and PFGE fingerprints have shown that epidemiologically unrelated strains have different fingerprints and epi-related strains have the same fingerprint RFLP/PFGE is now considered by many investigators as the "gold standard" for strain-typing most bacterial pathogens.

Figure 1.

   1     2     3       4      5      6       7      8      9    10

The figure above (see figure 1 attached) illustrates the previous point. Fingerprints in lanes 3-8 are from Neisseria meninigitidis isolates from 6 individuals who were part of a recent outbreak in northeast Florida. Notice that the DNA fingerprints are identical, thus confirming what the state epidemiologists suspected, i.e., that these individuals were infected with the same strain. Interestingly, patients with fingerprints in lanes 1, 2, 9 and 10, also Neisseria meninigitidis isolates, were diagnosed during the same time period as patients from the suspected outbreak (lanes 3-8). These individuals although not geographically located near the outbreak-epicenter could have been part of the outbreak; RFLP/PFGE analysis however ruled this out. This outbreak/ non-outbreak group of Neisseria meningitidis isolates is an excellent example of how RFLP/PFGE is used to differentiate bacterial strains and complement epidemiological investigations.

Infection control practitioners working in hospitals have also benefited from DNA fingerprinting data. Nosocomial outbreaks can be difficult to detect due to limited strain information, however RFLP/PFGE has been used to successfully investigate hospital strains. Below (see figure 2 attached) is pulsed field gel showing fingerprints of methicillin-resistant Staphylococcus aureus (MRSA) isolates taken from infants in a neonatal ICU.

Fingerprints in lanes 1, 2, 3, 4, 7 and 8 are identical suggesting the same MRSA strain has infected those infants. Lanes 6 and 9 contain patterns that are unrelated to each other and the "outbreak" strain. In this case, PFGE has identified three different strains of MRSA.

RFLP/PFGE services are available at the Bureau of Laboratories in Jacksonville. Inquiries and requests should be directed to your regional epidemiologist, listed below or the Bureau of Epidemiology.

A worker at a popular restaurant off of Interstate 95 in Smithfield (Johnston County), North Carolina was recently diagnosed with the hepatitis A virus. Johnston County Health Director L. S. Woodall says that as many as 2,000 diners may have been exposed to hepatitis A on July 31, August 1, August 2, August 7, or August 8 after 3:00 p.m. The restaurant is close to the popular Carolina Pottery shopping area, so many of the potentially exposed individuals may live in other states. Johnston County's health department is requesting assistance in disseminating the information.

"The CDC is sponsoring a public service announcement (PSAs) campaign to advise individuals who received blood transfusions before July 1992 to ask their doctor about being tested for HCV infection. These advertisements are part of the efforts to carry out general notification (lookback) of prior transfusions recipients to complement the blood industries' targeted notification efforts. The messages common to these efforts are "Hepatitis C: You May Be at Risk if You Had a Blood Transfusion Before July 1992. Ask your doctor if you should be tested." The PSAs will be in both English and Spanish.

September 30 - October 1, 1999

Belleview Biltmore Hotel, Clearwater FL.

FLORIDA DEPARTMENT OF HEALTH

BUREAU OF EPIDEMIOLOGY

We are pleased to invite you to the Sixth Annual Statewide Epidemiology Seminar to be held at the Belleview Biltmore Hotel, Clearwater, Florida. Attendance is open to all interested parties. Continuing Professional Education (Nursing CEU’s, Epi-Lab. Certification, Environmental-Epi Certification, etc.) credits are being solicited. Register early for a fee discount and submit your registration to the Gulfcoast North Area Health Education Center.

Students enrolled in a public health program are offered a reduced registration fee (50% off of the regular registration). A copy of a valid student photo ID or other proof of enrollment must be presented for registration. Please contact John Werth, Bureau Education Coordinator, should you have questions regarding student registration or opportunities for students to assist with the Annual Seminar.

The meeting provides current information and education to health care professionals regarding the reporting, investigation, and control of communicable and non-infectious diseases of public health significance, with the focus of improving the health of Florida residents and visitors.

The primary audience is county health department epidemiology and other related staff. Private physicians, practitioners, professionals in infection control, state and private laboratory staff, etc. are also welcome. Students enrolled in a public health program are also encouraged to participate in the annual seminar.

The contracted room rate (held until September 1), is eighty-one dollars ($81.00) plus taxes for single/double occupancy, and the rate extends for the immediate weekend if you desire to stay and visit. Participants must make hotel reservations by September 1^st to guarantee rate and availability.

If you cannot attend the meeting, please cancel your reservations no later than seven (7) days prior to your scheduled arrival date to avoid forfeiture of deposit.

6. Florida Past – Creation of the State Anti-Tuberculosis Association

From the time of its establishment, the State Board of Health was actively involved in combating tuberculosis in many communities throughout the state. After the turn of the century these efforts were in collaboration with the National Association for the Study and Prevention of Tuberculosis or local chapters of the General Federation of Women’s Clubs. In 1908, following the Sixth International Congress on Tuberculosis in Washington, D.C., the Duval County Anti-Tuberculosis Association was organized in Jacksonville. Other local organizations began to form and in 1916 the Florida Anti-Tuberculosis Association was established. The following excerpts were taken from the 1966 Annual Report of the Florida Tuberculosis and Respiratory Disease Association commemorating the 50^th anniversary of the organization that is now known as the Florida Lung Association.

Editorial Note: In 1921, the organization was renamed the Florida Public Health Association. During the next decade efforts were focused on: 1) developing health education programs in schools, 2) promoting an "Early Diagnosis Campaign" to TB test children in cooperation with the State Board of Health, 3) networking with medical and dental societies throughout the state and, 4) promoting a bill for creation of a State Tuberculosis Sanatorium Board, including establishment of a state tuberculosis sanatorium. The organization was renamed the Florida Tuberculosis and Health Association on November 10, 1930 to pave the way for the creation of new organization for public health personnel throughout the state that would be called the Florida Public Health Association.