Prospective study of respiratory infections at the U.S. Naval Academy.

Midshipmen at the U.S. Naval Academy have recently suffered epidemics of upper respiratory tract infections. Seeking to determine cause, in June 1998 we enrolled 1,243 (99.5%) of 1,249 new midshipmen (plebes) and followed them during their first 11 months of training. Eighty-five plebes sought medical attention for acute respiratory disease. Using culture, serologic studies, and polymerase chain reaction, considerable evidence for respiratory pathogen infection was found among the ill subjects: Chlamydia pneumoniae in 41 (52.6%), Mycoplasma pneumoniae in 19 (25.3%), influenza in 11 (14.2%), Streptococcus pneumoniae in 6 (7.3%), and adenovirus in 1 (1.2%). Additionally, 873 (81%) the 1,077 plebes who completed an end-of-year questionnaire complained of having one or more respiratory symptoms (> 12 hours) during their first year of school. Of these, 132 (15%) reported that the symptoms significantly affected their performance. Study results suggest that respiratory infections were frequent, had a significant adverse impact on training, and were often attributable to bacterial pathogens.

Randomized, placebo-controlled clinical trial of oral azithromycin prophylaxis against respiratory infections in a high-risk, young adult population.

Military Special Forces trainees undergo intense psychological and physical stressors that often lead to respiratory infection. During 1998-2000, 477 Navy Special Forces trainees were enrolled in a double-blind trial of oral azithromycin (1 g given weekly) plus a placebo injection, compared with benzathine penicillin G (1.2 million U) plus azithromycin placebo tablets. Among the 464 subjects with complete data, 44 developed acute respiratory infection (20 with pneumonia) during the 2 weeks of most intense training; of these subjects, 12 (27.3%) had evidence of Chlamydia pneumoniae infection and 7 (15.9%) had evidence of Mycoplasma pneumoniae infection. Trainees who received azithromycin were less likely than were trainees who received benzathine penicillin G to develop acute respiratory infection (risk ratio, 0.50; 95% confidence interval [CI], 0.28-0.92) and less likely at the end of training to report episodes of breathing difficulty (odds ratio [OR], 0.59; 95% CI, 0.34-1.01) or sore throat (OR, 0.66; 95% CI, 0.41-1.05). Compared with benzathine penicillin G prophylaxis, weekly oral azithromycin was superior in preventing respiratory infection in this population at transient high risk.

National Department of Defense Surveillance for Invasive Streptococcus pneumoniae: antibiotic resistance, serotype distribution, and arbitrarily primed polymerase chain reaction analyses.

To provide surveillance among US military personnel and their beneficiaries, 157 invasive Streptococcus pneumoniae clinical isolates were collected systematically from 7 large military hospitals between August 1997 and August 1999. The isolates were studied for antibiotic resistance, and 120 were serotyped and subjected to arbitrarily primed polymerase chain reaction (AP-PCR). Fifty (31.9%) of 157 isolates had intermediate or high-level resistance to penicillin, and 15.9% had multidrug resistance. The most common serotypes were 4, 6B, 9V, 14, 19F, and 23F. Those serotypes associated with penicillin resistance were 6B, 9V, 19A, and 19F. Most invasive disease cases were caused by serotypes included in the currently available 23- and 7-valent pneumococcal vaccines. By use of AP-PCR, 4 DNA groups were correlated with health care site (P< or =.0001). These results are valuable in assessing appropriate use of antibiotics and vaccines against S. pneumoniae in both military personnel and their families.

Survival of aerobic and anaerobic bacteria in purulent clinical specimens maintained in the Copan Venturi Transystem and Becton Dickinson Port-a-Cul transport systems.

Recovery of aerobic and anaerobic bacteria from clinical specimens maintained in the Copan Venturi Transystem and the Becton Dickinson Port-a-Cul transport was assessed. Of 54 anaerobes, 53 were recovered after 4 h, and 52 were recovered after 24 h, from both systems. After 48 h, 45 and 50 were recovered from the two systems, respectively.

Characterization of Bacteroides forsythus strains from cat and dog bite wounds in humans and comparison with monkey and human oral strains.

Bacteroides forsythus strains recovered from cat and dog bite wound infections in humans (n = 3), monkey oral strains (n = 3), and the human oral ATCC 43037 type strain were characterized by using phenotypic characteristics, enzymatic tests, whole cell fatty acid analysis, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis, PCR fingerprinting, and 16S rDNA (genes coding for rRNA) sequencing. All three bite wound isolates grew on brucella agar supplemented with 5% sheep blood, vitamin K1, and hemin. These strains, unlike the ATCC strain and previously described monkey oral and human clinical strains, did not require N-acetylmuramic acid supplementation for growth as pure cultures. However, their phenotypic characteristics, except for catalase production, were similar to those of previously identified strains. PCR fingerprinting analysis showed differences in band patterns from the ATCC strain. Also, SDS-PAGE and whole cell fatty acid analysis indicated that the dog and cat bite wound strains were similar but not identical to the human B. forsythus ATCC 43037 type strain and the monkey oral strains. The rDNA sequence analysis indicated that the three bite wound isolates had 99.93% homology with each other and 98.9 and 99.22% homology with the human ATCC 43037 and monkey oral strains, respectively. These results suggest that there are host-specific variations within each group.

Evaluation of the RapID CB Plus system for identification of Corynebacterium species and other gram-positive rods.

Due to the difficulty of identifying Corynebacterium spp. with standard methods, we compared them with the RapID CB Plus system (Remel, Lenexa, Kans. [formerly Innovative Diagnostic Systems, Norcross, Ga.]), which consists of 4 carbohydrate and 14 preformed enzyme tests, for the identification of 98 clinical isolates of Corynebacterium sp., other coryneforms, Listeria monocytogenes, and 17 ATCC strains. Forty (95%) of 42 strains of Corynebacterium spp. were accurately identified to the species level by the RapID CB Plus system, and two additional strains of C. striatum were identified with one additional conventional test for lipid requirement. Twenty-seven (75%) of the 36 coryneform strains tested were identified correctly to the species level. However, three of four strains of Brevibacterium sp. and all seven of the L. monocytogenes strains were identified to the genus level only. Actinomyces strains had variable results, and the one strain of Arcanobacterium haemolyticum tested was not identified. Overall, the RapID CB Plus system compared favorably with the conventional methods, was easy to inoculate and interpret, and is promising as a new method for identification of gram-positive bacilli.

Evaluation of a novel specimen transport system (Venturi Transystem) for anaerobic bacteria.

The Venturi Transystem (Copan Diagnostics, Corona, CA), with and without charcoal, is designed for transport of clinical specimens. It was evaluated for its ability to maintain the viability of pure cultures of selected anaerobic bacteria. Results indicated that the system supported survival of test strains within the time frame that most clinical specimens require to reach the clinical laboratory.

Bilophila wadsworthia clinical isolates compared by polymerase chain reaction fingerprinting.

Bilophila wadsworthia isolates recovered from a right-ear cholesteatoma and brain abscess of the same patient were analyzed by means of polymerase chain reaction (PCR) fingerprinting with single primers (T3B and M13 core) to ascertain if they originated from the same clone. Their PCR fingerprint profiles were compared with those of three additional B. wadsworthia clinical isolates and the type strain (ATCC 49260). The two isolates from the same patient produced PCR fingerprint profiles identical to each other, regardless of which primer was used. All isolates' PCR fingerprint profiles, with use of either the T3B or M13 core primer, shared some major and minor bands. However, differences in additional major and minor bands distinguished each of the additional isolates, suggesting that there are different subgroups of B. wadsworthia.

Growth characteristics and a novel method for identification (the WEE-TAB system) of Porphyromonas species isolated from infected dog and cat bite wounds in humans.

Thirty-nine clinical isolates of Porphyromonas species recovered from infected cat and dog bite wounds in humans and eight American Type Culture Collection and National Collection of Type Cultures type strains were characterized by using the API ZYM system, the RapID ANA II system, and conventional biochemical methods. Growth characteristics on various agar media were compared. All strains grew on brucella blood agar supplemented with vitamin K1 and hemin and on brucella laked blood agar supplemented with vitamin K1 and hemin. In contrast, only 34% of strains grew on unsupplemented brucella blood agar, 62% grew on Columbia blood agar, and 70% grew on tryptic soy blood agar (the last three media did not contain vitamin K1 or hemin). The ability of the single-tube, triple-substrate WEE-TAB system to detect the preformed enzymes N-acetyl-beta-D-glucosaminidase, alpha-D-galactosidase, beta-D-galactosidase, alpha-fucosidase, trypsin-like activity, and chymotrypsin was evaluated. The WEE-TAB test results were easy to interpret; the WEE-TAB tests were more sensitive than the comparable tests with the API ZYM and RapID ANA II systems for the detection of alpha-D-galactosidase, beta-D-galactosidase, trypsin, and chymotrypsin, and the WEE-TAB tests accurately identified Porphyromonas species.