Multiple-dose medications and reliance on benzalkonium chloride as a medication preservative provide a mechanism for nosocomial spread of microorganisms, particularly if infection control procedures are not carefully followed. Repetitive-element PCR is a useful fingerprinting technique for molecular epidemiologic studies of B. cepacia.

Repetitive-element PCR (rep-PCR) with primers based on repetitive extragenic palindromic (REP) and enterobacterial repetitive intergenic consensus (ERIC) repeated DNA sequences was used for genomic fingerprinting of Bartonella species. This technique was applied by using either extracted genomic DNA or preparations of whole bacterial cells directly. PCR fingerprints with either the REP-based primers (REP-PCR) or primers based on the ERIC repeat (ERIC-PCR) revealed species-specific band patterns for the various Bartonella isolates. DNA fingerprints obtained from rep-PCR of extracted genomic DNA or from preparations of whole cells yielded comparable patterns. ERIC-PCR banding patterns were less complex than those obtained by REP-PCR but allowed better discrimination between strains within species. By combining results of REP-PCR and ERIC-PCR, five different fingerprint profiles were identified among 17 isolates of Bartonella henselae, but only one profile was identified among the five isolates of Bartonella quintana. Other Bartonella species yielded distinct rep-PCR fingerprints. rep-PCR is a useful technique for identification of Bartonella organisms to the species level and offers the advantage of ease of performance, with only small quantities of cells needed for the whole-cell procedure. This technique also appears to be useful for subtyping B. henselae isolates.

Pharyngeal colonization by Streptococcus pneumoniae was evaluated in 103 human immunodeficiency virus (HIV)-infected subjects (<200 CD4 cells/microL, 57; > or = 200 CD4 cells/microL, 46) and 39 non-HIV-infected controls who were participants in a vaccine study. At baseline, 7%, 20%, and 10% of subjects in the <200 and > or = 200 CD4 cell groups and in the control group were colonized with S. pneumoniae: Rates at 6 months were 23%, 22%, and 0%, respectively. Of 34 isolates from HIV-infected subjects, 25 were penicillin-resistant and 19 were resistant to > or = 3 antimicrobials; of 8 isolates from controls, 1 was resistant. Resistance to trimethoprim-sulfamethoxazole was significantly higher among HIV-infected subjects with <200 CD4 cells/microL than in those with more CD4 cells. Polymerase chain reaction DNA analysis with BOX primers demonstrated that 12 HIV-infected subjects were persistently colonized with the same S. pneumoniae strain for > or = 1 month compared with none of the controls. HIV-infected subjects were more likely to be persistent pneumococcal carriers and to carry antibiotic-resistant isolates than were non-HIV-infected subjects.

In 1990, there was a significant increase in the number of lower respiratory tract infections and surgical wound infections in the adult intensive care units of our tertiary care teaching hospital caused by Acinetobacter baumannii compared with the number in 1989. During the 5-month period from April through August 1990, 84 isolates ofA. baumannii were recovered from 50 hospitalized patients. Biotyping, comparison of antibiograms, plasmid analysis, and DNA polymorphisms of 20 isolates from 20 different patients, determined by the use of repetitive element PCR with primers aimed at repetitive extragenic palindromic sequences and enterobacterial repetitive intergenic consensus sequences, were used to investigate this apparent outbreak Biotyping, antibiograms, plasmid analysis, and enterobacterial repetitive intergenic consensus PCR were not useful epidemiologically. Repetitive element PCR-mediated DNA fingerprinting using repetitive extragenic palindromic primers discriminated between epidemic and sporadic strains ofA. baumannii and demonstrated four discrete clusters which were unique epidemiologically. Acinetobacter baumannii (4) or Acinetobacter calcoaceticus-Acinetobacter baumannii complex (17) (formerly classified as A. calcoaceticus subsp. anitratus) is a nonfermentative, aerobic gram-negative bacillus that is ubiquitous in the environment and found commonly as part of the normal flora of humans (3, 41). It has been reported with increasing frequency in sporadic outbreaks of nosocomial infections, often in association with contamination of hospital equipment or colonization on the hands of health care workers (6, 7, 25, 27, 33, 34, 37). The most frequent site of infection with A. baumannii is the lower respiratory tract (6). Urinary tract infections, wound infections, and bacteremia are also common (13, 19, 26, 35, 37). Although several methods have been used for typing of Acinetobacter strains, including biotyping, bacteriocin typing, serotyping, and phage typing, comparison of antibiograms, whole cell and cell envelope protein profiles, enzyme profiles, plasmid analysis, ribotyping, and determination of DNA restriction fragment length polymorphisms by pulsed-field gel electrophoresis, there is no generally accepted typing scheme for epidemiologic studies of this organism (1, 2, 5, 9, 10, 17, 21, 24, 29, 42, 46). Recently, PCR fingerprinting using a single primer derived from the core sequence of phage M13 was applied to characterizeA. baumannii isolates from an outbreak in an anesthesiologic intensive care unit (ICU) (22). Compared with other DNA-based strain identification methods, PCR fingerprinting was found to be simple and rapid and effectively demonstrated strain discrimination (22). Hahnemann University Hospital is a 630-bed tertiary care teaching hospital. In 1990, there was a significant increase in the number of lower respiratory tract infections and surgical wound infections in the adult ICUs caused by A. baumannii compared with 1989 numbers. In 1990, 54 of 472 lower

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