OXA-23 and OXA-40 producing carbapenem-resistant Acinetobacter baumannii in Central Illinois.

We reviewed susceptibility of 840 A. baumannii complex isolates at two academic medical centers and explored their mechanism of carbapenem resistance. Carbapenem resistance rates among A. baumannii increased from <5% before 2005 to 55% in 2011 and declined thereafter. We subjected 86 isolates for further antibiotic susceptibility testing using E-test, screened for MBL and carbapenemase production, and performed PCR for blaOXA genes. Statistical analyses included correlation of resistance genes with susceptibility. Sixty-one isolates were non-susceptible to carbapenems (MIC >2 µg/mL). Phenotypic screening showed carbapenemase production in 50 isolates, but none was positive for MBL. Among carbapenem non-susceptible isolates, the CHDL (group D carbapenemase) encoding genes blaOXA-23 (52%) and blaOXA-40 (28%) were the most frequent genes. In conclusion, carbapenem resistance rates in A. baumannii peaked in 2011 and have since declined in our region. Carbapenem resistance among A. baumannii was primarily associated with production of acquired CHDLs including OXA-23 and OXA-40.

Decreased mortality associated with prompt Gram staining of blood cultures.

Gram stains of positive blood cultures are the most important factor influencing appropriate therapy. The sooner appropriate therapy is initiated, the better. Therefore, it is reasonable to expect that the sooner Gram stains are performed, the better. To determine the value of timely Gram stains and whether improvement in Gram stain turnaround time (TAT) is feasible, we compared data for matched pairs of patients with cultures processed promptly (<1 hour TAT) with data for patients with cultures not processed promptly (> or =1 hour TAT) and then monitored TAT by control charting.In 99 matched pairs, average difference in time to detection of positive blood cultures within a pair of patients was less than 0.1 hour. For the less than 1 hour TAT group, the average TAT and crude mortality were 0.1 hour and 10.1%, respectively; for the 1 hour or longer TAT group, they were 3.3 hours and 19.2%, respectively (P < .0001 and P = .0389, respectively). After multifaceted efforts, we achieved significant improvement in the TAT for Gram stains.

Prevalence of human metapneumovirus in central illinois in patients thought to have respiratory viral infection.

Studies suggest that by age 5 years nearly all people have been exposed to metapneumovirus. To determine its prevalence in central Illinois, we tested respiratory secretions by direct immunofluorescence staining from December to March. Metapneumovirus was detected in 11/391 specimens. The distribution of metapneumovirus was bimodal, with the split being between children aged

Evaluating antibiograms to monitor drug resistance.

We used hospital antibiograms to assess predominant pathogens and their patterns of in vitro antimicrobial resistance in central Illinois, USA. We found a lack of information about national guidelines for in vitro antimicrobial susceptibility testing and differences in interpretation among laboratories in the region.

Comparison of Easy-Flow Copan Liquid Stuart's and Starplex Swab transport systems for recovery of fastidious aerobic bacteria.

Because samples are frequently submitted on swabs from distant sites, viability of the organism must be maintained. We compared two transport systems, a new Copan Liquid Stuart's swab with an Easy-Flow swab applicator and the Starplex Liquid Stuart's swab. The purpose of the study was to assess the release and/or recovery of organisms from the Copan system compared to that from Starplex. Triplicate swabs were seeded with 3 dilutions of Neisseria gonorrhoeae, Neisseria meningitidis, Haemophilus influenzae, and Streptococcus pneumoniae. Although the amount of the initial inoculum was the same for both transport systems, recovery by the roll-plate method at time zero was consistently increased with the Copan system (31 to 87% higher). This is the most important finding in this study. With N. gonorrhoeae, subsequent recoveries were similar for Copan and Starplex but poor for both systems. With N. meningitidis and Haemophilus, higher levels of recovery were clearly obtained with Copan (P < 0.05 to P < 0.001). With Streptococcus, subsequent recoveries for Copan and Starplex were mixed. In conclusion, Copan generally demonstrated better recovery of organisms compared to Starplex even (and especially) at time zero.

Comparison of chlorhexidine and tincture of iodine for skin antisepsis in preparation for blood sample collection.

Rates of contamination of blood cultures obtained when skin was prepared with iodine tincture versus chlorhexidine were compared. For iodine tincture, the contamination rate was 2.7%; for chlorhexidine, it was 3.1%. The 0.41% difference is not statistically significant. Chlorhexidine has comparable effectiveness and is safer, cheaper, and preferred by staff, so it is an alternative to iodine tincture.

Nonvalue of culturing cerebrospinal fluid for fungi.

No studies have evaluated the efficacy of culturing cerebrospinal fluid (CSF) for fungi. Because of the facts that the most common fungi responsible for meningitis grow well in media utilized for routine bacterial cultures and that cryptococcal antigen tests are commonly ordered, the efficacy of routinely performing fungal cultures specifically to recover fungi has been questioned. We examined data from 1225 samples of CSF which were cultured for both bacteria and fungi. Twelve specimens yielded fungi, 10 from fungal cultures and 8 from bacterial cultures. Cryptococcus neoformans was found in 10 specimens, Candida albicans was found in 1, and a Cladosporium sp. was found in 1. Eight of 12 positive specimens had concordant culture results. The discordant cases were one specimen that was bacterial culture positive but fungal culture negative and three specimens that were fungal culture positive but bacterial culture negative. Of the latter discrepant cultures, one had fungal contamination only and the other two were positive for cryptococcal antigen. Therefore, omitting the fungal cultures on these specimens would not adversely impact patients. When both cryptococcal antigen tests and bacterial cultures are ordered routinely, eliminating fungal cultures on CSF would have had no impact on the patients in this study. All the clinically significant fungi were detected by the cryptococcal antigen test and/or bacterial culture. With a few exceptions, the combined use of cryptococcal antigen test and bacterial cultures of CSF could replace routine fungal cultures of CSF. Exceptions include settings where fungal pathogens other than Cryptococcus and Candida remain important causes of meningitis.

Improved outcomes associated with limiting identification of Candida spp. in respiratory secretions.

Pneumonia due to infection with Candida spp. is extremely rare even though these yeasts are commonly cultured from respiratory secretions. The diagnosis of pneumonia due to Candida spp. should be made only by demonstrating tissue invasion of a biopsy specimen. Physicians might misinterpret the presence of Candida spp. in respiratory secretions as being the etiological agent of pneumonia. This study describes the practice of limiting identification (ID) of rapidly growing yeasts (i.e., Candida spp.) in respiratory secretions and its impact on patients. Before November 2001, rapidly growing yeasts found in respiratory secretions were identified to the species level. After November, rapidly growing yeasts were reported as "yeasts, not Cryptococcus." The group of patients with respiratory secretions processed before November 2001 is called the full ID group (n = 267); the group with samples processed after that date is called the limited ID group (n = 77). Full ID patients had an average length of hospital stay of 12.1 days/patient; that of limited ID patients was 10.1 days/patient, a decrease of 2 days/patient (P = 0.02). The full ID patients had an average cost of 9,407 dollars/patient; that of limited ID patients was 6,973 dollars/patient, a decrease of 2,434 dollars/patient (P = 0.03). Antifungal medications were used in 103 of 267 (39%) full ID patients and in 16 of 77 (21%) limited ID patients, a decrease of 18% (P = 0.004). Limited ID patients had a mortality rate of 14.3%; that of full ID patients was 18.7%, a decrease of 4.4% (P = 0.37). This policy of limiting yeast ID did not impair the diagnosis of pneumonia. Rather, decreases in lengths of stay, costs, and administration of unnecessary antifungal therapy were observed after instituting this policy.

Outcomes of improved anaerobic techniques in clinical microbiology.

To our knowledge, the effects of the use of improved anaerobic techniques have not been documented. We compared data on patients during 2 different time periods-the first when anaerobic cultures were done by standard techniques (the control or "before" group) and the second when anaerobic cultures were done after an intensive program to improve anaerobic techniques (IAT). The program consisted of the use of an anaerobe chamber, improved anaerobic transport and media, and education of clinicians and microbiologists. There were 74 diagnosis-related group (DRG)-matched patients in the controls and 76 in the IAT group. The average turnaround time for preliminary anaerobic data was decreased in the IAT group (124 hours per specimen for controls and 107 for IAT, P=.001). The cost of achieving anaerobic conditions for a plate was approximately $0.09 when the anaerobic chamber was used and $0.96 when the bio-bag system was used. The crude mortality rate was 10.8% in controls and 1.3% in the IAT group (P=.06). The average length of stay was 10.2 days per patient in controls and 8.9 in the IAT group (P=.91). The average variable cost was $6865 per patient in the control group and $4432 in the IAT group (P=.21). The average laboratory cost was $723 per patient in the control group and $380 in the IAT group (P=.08). In conclusion, benefits associated with improved anaerobic testing were documented. We could expect to save >$630,000 every year with improved anaerobic processes.