Guillermo J. Vázquez

Detection of KPC in Acinetobacter spp. in Puerto Rico

ABSTRACT During an island-wide PCR-based surveillance study of beta-lactam resistance in multidrug-resistant (MDR) Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Acinetobacter calcoaceticus-baumannii complex isolates obtained from 17 different hospitals, 10 KPC-positive Acinetobacter isolates were identified. DNA sequencing of the blaKPC gene identified KPC-2, -3, and -4 and a novel variant, KPC-10. This is the first report of a KPC-type beta-lactamase identified in Acinetobacter species.

Paromomycin: No More Effective than Placebo for Treatment of Cryptosporidiosis in Patients with Advanced Human Immunodeficiency Virus Infection

To evaluate the efficacy of paromomycin for the treatment of symptomatic cryptosporidial enteritis in human immunodeficiency virus-infected adults, we conducted a prospective, randomized, double-blind, placebo-controlled trial before the widespread introduction of highly active antiretroviral therapy (HAART). Seven units under the auspices of the AIDS Clinical Trials Group enrolled 35 adults with CD4 cell counts of < or = 150/mm(3). Initially, 17 patients received paromomycin (500 mg 4 times daily) and 18 received matching placebo for 21 days. Then all patients received paromomycin (500 mg q.i.d.) for an additional 21 days. Clinical definitions of response were measured by an average number of bowel movements per day in association with concurrent need for antidiarrheal agents that was lower than that before study entry. There was no treatment response during the placebo-controlled phase of the study according to protocol-defined criteria (P=.88). Three paromomycin recipients (17.6%) versus 2 placebo recipients (14.3%) responded completely. Rates of combined partial and complete responses in the paromomycin arm (8 out of 17, 47.1%) and the placebo arm (5 out of 14, 35.7%) of the study were also similar (P=.72). The clinical course of cryptosporidiosis was quite variable. Paromomycin was not shown to be more effective than placebo for the treatment of symptomatic cryptosporidial enteritis. However, inadequate statistical power prevents definitive rejection of the usefulness of paromomycin as therapy for this infection.

Outbreak of Carbapenem-Resistant Klebsiella pneumoniae in Puerto Rico Associated with a Novel Carbapenemase Variant

BACKGROUND Carbapenem-resistant Klebsiella pneumoniae (CRKP) is resistant to almost all antimicrobial agents, and CRKP infections are associated with substantial morbidity and mortality. OBJECTIVE To describe an outbreak of CRKP in Puerto Rico, determine risk factors for CRKP acquisition, and detail the successful measures taken to control the outbreak. DESIGN Two case-control studies. SETTING A 328-bed tertiary care teaching hospital. PATIENTS Twenty-six CRKP case patients identified during the outbreak period of February through September 2008, 26 randomly selected uninfected control patients, and 26 randomly selected control patients with carbapenem-susceptible K. pneumoniae (CSKP) hospitalized during the same period. METHODS We performed active case finding, including retrospective review of the hospitals microbiology database and prospective perirectal surveillance culture sampling in high-risk units. Case patients were compared with each control group while controlling for time at risk. We sequenced the bla(KPC) gene with polymerase chain reaction for 7 outbreak isolates and subtyped these isolates with pulsed-field gel electrophoresis. RESULTS In matched, multivariable analysis, the presence of wounds (hazard ratio, 19.0 [95% confidence interval {CI}, 2.5-142.0]) was associated with CRKP compared with no K. pneumoniae. Transfer between units (adjusted odds ratio [OR], 7.5 [95% CI, 1.8-31.1]), surgery (adjusted OR, 4.0 [95% CI, 1.0-15.7]), and wounds (adjusted OR, 4.9 [95% CI, 1.1-21.8]) were independent risk factors for CRKP compared to CSKP. A novel K. pneumoniae carbapenemase variant (KPC-8) was present in 5 isolates. Implementation of active surveillance for CRKP colonization and cohorting of CRKP patients rapidly controlled the outbreak. CONCLUSIONS Enhanced surveillance for CRKP colonization and intensified infection control measures that include limiting the physical distribution of patients can reduce CRKP transmission during an outbreak.

Surveillance of Carbapenem-Resistant Pseudomonas aeruginosa Isolates from Puerto Rican Medical Center Hospitals: Dissemination of KPC and IMP-18 β-Lactamases

ABSTRACT During a 6-month period, 37/513 (7.2%) Pseudomonas aeruginosa isolates belonging to 13 pulsed-field gel electrophoresis (PFGE) groups from Puerto Rican hospitals were carbapenem nonsusceptible. Seven of 37 isolates from four PFGE groups carried blaIMP-18, and 25/37 isolates from seven PFGE groups carried blaKPC. The results indicated the clonal spread of blaKPC-positive P. aeruginosa isolates into several Puerto Rican hospitals and the dissemination of blaIMP-18 and blaKPC into genetically unrelated isolates.

Detection of the KPC Gene in Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Acinetobacter baumannii during a PCR-Based Nosocomial Surveillance Study in Puerto Rico

ABSTRACT A 6-month, PCR-based, island-wide hospital surveillance study of beta-lactam resistance in Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Acinetobacter baumannii was conducted in Puerto Rico. Of 10,507 isolates, 1,239 (12%) unique, multi-beta-lactam-resistant isolates from all geographical regions were identified. The KPC gene was detected in 61 E. coli, 333 K. pneumoniae, 99 P. aeruginosa, and 41 A. baumannii isolates, indicating the widespread dissemination of the KPC gene in clinically significant nosocomial isolates.

Switching to Nevirapine Decreases Insulin Levels but Does Not Improve Subcutaneous Adipocyte Apoptosis in Patients with Highly Active Antiretroviral Therapy–Associated Lipodystrophy

Subcutaneous adipocyte apoptosis occurs in lipotrophic areas of patients with highly active antiretroviral therapy (HAART)-associated lipodystrophy. Fourteen patients with HAART-associated lipodystrophy had 2 subcutaneous biopsies for evidence of adipocyte apoptosis, the second after a randomized change to nevirapine (n=8) or after remaining on a regimen of indinavir-based HAART (n=6). Apoptosis was assessed by the terminal deoxynucleotidyl transferase dUTP-digoxigenin nick end-labeling method. Patients who were switched to nevirapine had a significant decrease in insulinemia and a significant increase in the glucose:insulin ratio. Overall, subcutaneous adipocyte apoptosis increased in 3 patients who were switched to nevirapine and in 3 who continued to receive indinavir but decreased in 2 patients switched to nevirapine and another 2 who continued to receive indinavir. Subcutaneous adipocyte apoptosis continues to occur in lipotrophic areas of patients with HAART-associated lipodystrophy despite switching from indinavir to nevirapine, suggesting that such a strategy will be useless for reversal of lipoatrophy.

Antibiotic Therapy of Experimental Staphylococcus epidermidis Endocarditis

Endocarditis was produced in rabbits with a methicillin-resistant Staphylococcus epidermidis isolate. Subpopulations resistant to other semisynthetic penicillins and cephalosporins were detected in the isolate. Their presence was probably responsible for the increase in minimum bactericidal concentrations and minimum inhibitory concentrations when tests with high inocula, rather than low inocula were pursued. Rabbits were treated for either 2 or 7 days with nafcillin, cephalothin, cefamandole, vancomycin, rifampin, or gentamicin. Spontaneous death was uncommon in either controls (84% survival) or treated animals (80 to 94% survival). There was no significant difference in the number of bacteria in vegetations of rabbits treated for 7 days with cephalothin, cefamandole, nafcillin, or no antibiotic (control). There was a significant reduction in total bacteria in vegetations of rabbits given vancomycin, gentamicin, or rifampin for 7 days as compared with cephalothin, cefamandole, nafcillin or control. Gentamicin or rifampin sterilized significantly more vegetations after 7 days than cephalothin, cefamandole, nafcillin, or control; rifampin was more effective in sterilizing vegetations than either gentamycin or vancomycin after 2 days. Mutants resistant to 10 μg of rifampin per ml comprised the total bacterial population cultured from vegetations of 2 of 17 rabbits treated with this antibiotic for 7 days; there was no change in the susceptibility of vegetation isolates to other antibiotics. Rifampin, vancomycin, or gentamicin may prove to be more effective in humans than cephalosporins or semisynthetic penicillins in the treatment of methicillin-resistant S. epidermidis endocarditis.

HIV-1 protease inhibitor–associated partial lipodystrophy: Clinicopathologic review of 14 cases

BACKGROUND A novel type of acquired partial lipodystrophy resulting from chronic treatment with HIV-1 protease inhibitor drugs has recently been described. OBJECTIVE We studied the clinical and histopathologic features of a series of patients with HIV-1 protease inhibitor-associated lipodystrophy to evaluate the frequency of associated abnormalities. METHODS The study group consisted of 14 consecutive HIV-infected patients receiving treatment with HIV-1 protease inhibitors, who experienced partial lipodystrophy. Clinical (including anthropometric data) and histopathologic findings, as well as biochemical and virologic data, were evaluated. RESULTS A significant loss of fat in the face and extremities was associated with fat deposition on the abdomen, breast, and dorsocervical fat pad. Central obesity was frequently present. Histopathologic features disclosed a peculiar type of involutional lipodystrophy. Hypertriglyceridemia was detected in 78.5% of patients. Low serum levels of cholesterol-high-density lipoprotein and high cholesterol-very-low-density lipoprotein were noted. Hyperglycemia, hypercholesterolemia, or hyperinsulinemia were occasionally detected. CONCLUSION HIV-1 protease inhibitor-associated lipodystrophy represents a new entity with peculiar clinical and histopathologic features. Metabolic associated abnormalities may imply a risk of future atherogenic complications.

Two novel class I integron arrays containing IMP-18 metallo-β-lactamase gene in Pseudomonas aeruginosa clinical isolates from Puerto Rico.

ABSTRACT During a β-lactam resistance surveillance study, 12 IMP-18-positive Pseudomonas aeruginosa isolates belonging to 9 different pulsed-field gel electrophoresis groups were identified. In nine isolates, a class I integron with a novel gene array was identified that contained blaIMP-18 and blaOXA-224, while in two isolates the class I integron contained blaIMP-18 and blaOXA-2 but in a new arrangement. Our findings show the dissemination of two novel class I integrons in P. aeruginosa from different regions of Puerto Rico.

Genetic environment of the KPC gene in Acinetobacter baumannii ST2 clone from Puerto Rico and genomic insights into its drug resistance.

Carbapenems are considered the last-resort antibiotics to treat infections caused by multidrug-resistant Gram-negative bacilli. The Klebsiella pneumoniae carbapenemase (KPC) enzyme hydrolyses β-lactam antibiotics including the carbapenems. KPC has been detected worldwide in Enterobacteriaceae and Pseudomonas aeruginosa isolates associated with transposon Tn4401 commonly located in plasmids. Acinetobacter baumannii has become an important multidrug-resistant nosocomial pathogen. KPC-producing A. baumannii has been reported to date only in Puerto Rico. The objective of this study was to determine the whole genomic sequence of a KPC-producing A. baumannii in order to (i) define its allelic diversity, (ii) identify the location and genetic environment of the blaKPC and (iii) detect additional mechanisms of antimicrobial resistance. Next-generation sequencing, Southern blot, PFGE, multilocus sequence typing and bioinformatics analysis were performed. The organism was assigned to the international ST2 clone. The blaKPC-2 was identified on a novel truncated version of Tn4401e (tentatively named Tn4401h), located in the chromosome within an IncA/C plasmid fragment derived from an Enterobacteriaceae, probably owing to insertion sequence IS26. A chromosomally located truncated Tn1 transposon harbouring a blaTEM-1 was found in a novel genetic environment within an antimicrobial resistance cluster. Additional resistance mechanisms included efflux pumps, non-β-lactam antibiotic inactivating enzymes within and outside a resistance island, two class 1 integrons, In439 and the novel In1252, as well as mutations in the topoisomerase and DNA gyrase genes which confer resistance to quinolones. The presence of the blaKPC in an already globally disseminated A. baumannii ST2 presents a serious threat of further dissemination.