Antibiotic-Resistant Infections and Treatment Challenges in the Immunocompromised Host.

This article reviews antibiotic resistance and treatment of bacterial infections in the growing number of patients who are immunocompromised: solid organ transplant recipients, the neutropenic host, and persons with human immunodeficiency virus and AIDS. Specific mechanisms of resistance in both gram-negative and gram-positive bacteria, as well as newer treatment options are addressed elsewhere, and are only briefly discussed in the context of the immunocompromised host.

Infections caused by fluoroquinolone-resistant Escherichia coli following transrectal ultrasound-guided biopsy of the prostate.

An increase in the number of infections with fluoroquinolone (FQ)-resistant Escherichia coli following transrectal ultrasound-guided biopsy of the prostate (TRUBP) was observed in Louis Stokes Cleveland Department of Veterans Affairs Medical Center. This study investigated whether these infections were caused by a single strain of E. coli possessing distinct resistance and virulence determinants. Of 15 patients with urinary tract infection, 5 were complicated with bacteraemia and 1 with prostate abscess. Thirteen FQ-resistant isolates demonstrated mutations in the quinolone resistance-determining regions (QRDRs) of gyrA and parC but did not contain plasmid-mediated quinolone resistance determinants; blaCTX-M and blaCMY as well as genes coding for extended-spectrum ß-lactamases were also absent. Genes encoding aminoglycoside-modifying enzymes were discovered in an isolate that was gentamicin-resistant. The most prevalent sequence type (ST) was ST43 (n = 7), corresponding to ST131 in Achtman's multilocus sequence typing (MLST) scheme. These isolates (i) were distinguished as >95% similar by repetitive sequence-based PCR (rep-PCR), (ii) belonged to the virulent phylogenetic group B2 and (iii) contained plasmid types FIB, FIA and Frep. Several other strain types were present (ST2, ST27, ST30, ST44, ST472, ST494, ST511 and ST627). Non-ST43 isolates infected patients with more co-morbidities but contained similar virulence factors (kpsMTII, iutA, papAH/papC and sfa/focDE). In our hospital, E. coli isolates causing TRUBP-related infection are quite heterogeneous (ST131 and other ST types) and are part of phylogenetic groups containing multiple virulence factors.

Modification of antimicrobial prophylaxis based on rectal culture results to prevent fluoroquinolone-resistant Escherichia coli infections after prostate biopsy.

For patients undergoing transrectal ultrasound-guided biopsy of the prostate (TRUBP), use of rectal screening culture results to guide antimicrobial prophylaxis was effective for prevention of fluoroquinolone-resistant Escherichia coli infections. In practice, elimination of infections after TRUBP required the rectal screening protocol and addition of gentamicin for patients missing prior screening.

Epidemiology of clostridium difficile and vancomycin-resistant Enterococcus colonization in patients on a spinal cord injury unit.

BACKGROUND/OBJECTIVE: Patients with spinal cord injury (SCI) are at risk of acquiring colonization with Clostridium difficile and vancomycin-resistant Enterococcus (VRE) due to prolonged hospitalization and frequent antimicrobial use. We examined the frequency of stool, skin, and environmental contamination with C. difficile and VRE in hospitalized patients with SCl. METHODS: We performed a cross-sectional study of 22 hospitalized patients with SCI with no symptoms of C. difficile infection. Stool samples, skin, and environmental sites were cultured for C. difficile and VRE, and polymerase chain reaction ribotyping was performed for C. difficile isolates. Fisher's exact test was used to compare the proportions of skin and environmental contamination among stool carriers and non-carriers. Univariate analysis was used to assess factors associated with asymptomatic carriage of C. difficile. RESULTS: Of 22 asymptomatic patients, 11 (50%) were asymptomatic carriers of toxigenic C. difficile and 12 (55%) were carriers of VRE. In comparison with non-carriers, asymptomatic carriers of toxigenic C. difficile had higher rates of skin (45 versus 9%) (P = 0.07) and environmental contamination (55 versus 9%) (P = 0.03) and longer length of stay (median, 57 versus 6 days; P = 0.04). A majority of skin and environmental C. difficile isolates from individuals were identical to isolates from stool. In comparison with non-carriers, patients with VRE stool colonization had non-significant trends toward more frequent skin (27 versus 9%) and environmental (18 versus 9%) contamination. CONCLUSION: Asymptomatic stool carriage of toxigenic C. difficile and VRE was common on an acute-care SCI unit. Asymptomatic carriers of toxigenic C. difficile had frequent skin and environmental contamination, suggesting the potential to contribute to transmission.

Survey of patients' knowledge and opinions regarding the use of indwelling urinary catheters.

In a survey of patients with short-term indwelling urinary catheters, 47% were aware that catheters cause urinary tract infections, 89% believed that catheters were not overused, and 68% preferred catheter placement rather than use of a bedside commode, bedpan, or diaper. Patient education is needed regarding the risks of urinary catheters.

What is on that keyboard? Detecting hidden environmental reservoirs of Clostridium difficile during an outbreak associated with North American pulsed-field gel electrophoresis type 1 strains.

BACKGROUND: Numerous studies have demonstrated that environmental surfaces in the rooms of patients with Clostridium difficile infection (CDI) are often contaminated with spores. However, less information is available regarding the frequency of contamination of environmental surfaces outside of CDI isolation rooms. METHODS: We performed a point-prevalence culture survey for C difficile in rooms of patients not in isolation for CDI, in physician and nurse work areas, and on portable equipment, including pulse oximetry devices, electrocardiogram machines, mobile computers, and medication distribution carts. Isolates were characterized by assessment of toxin production, polymerase chain reaction (PCR) ribotyping, and PCR for binary toxin genes. RESULTS: Of 105 nonisolation rooms, 17 (16%) were contaminated with toxin-producing C difficile, with the highest rate of contamination on the spinal cord injury unit (32%). Of 87 surfaces cultured outside of patient rooms, 20 (23%) were contaminated, including 9 of 29 (31%) in physician work areas, 1 of 10 (10%) in nurse work areas, and 9 of 43 (21%) portable pieces of equipment, including a pulse oximetry finger probe, medication carts, and bar code scanners on medication carts. Of 26 isolates subjected to typing, 19 (73%) matched ribotype patterns detected in stool samples from CDI patients and 13 (50%) were epidemic, binary toxin-positive strains. CONCLUSION: In the context of a CDI outbreak, we found that environmental contamination was common in nonisolation rooms, in physician and nurse work areas, and on portable equipment. Further research is needed to determine whether contamination in these areas plays a significant role in transmission.