Therapeutic Use Of Antibiotics Research Articles

P152. Is lipomodelling after breast cancer safe?

P152. Is lipomodelling after breast cancer safe?

Occurrence and characterization of Campylobacter spp.isolates in dogs, cats and children

To improve the understanding of implications of Campylobacterspp. infections in pets and children of different environments were analysed 160 faecal samples from children and 120 from pets (103 dogs and 17 cats). Campylobacter spp. were detected in 6.87% of the children and in 18.3% of the dogs and cats. From 33 stool samples positive for Campylobacter spp., 57.6% were identified as C. jejuni, and 33.4% were identified as C. coli. More than 50% of the isolates in pets were resistant to ceftiofur, sulphazotrim, norfloxacin and tetracycline. In humans, most of the isolates were resistant to amoxicillin, cefazolin, ceftiofur, erythromycin and norfloxacin. From 19 isolates of C. jejuni, 11 isolates from children and 5 from dogs contained two to four of the virulence genes flaA, pldA, cadF or ciaB.We found an association between the presence of virulence genes and diarrhoea. Furthermore, an association was observed between the presence of Campylobacter spp. and diarrhoea in dewormed pets with blood picture suggestive of bacterial infection, and the therapeutic use of antibiotics was associated with more positive detection of Campylobacterspp. in the faeces of pets. Our data indicate that virulent strains of Campylobacter spp. can be risk factor to diarrhoea in animals, and that high resistance to antimicrobial agents is common in pets.

Efficacy, safety, and tolerability of IVIG-SN in patients with primary immunodeficiency

Background: IVIG-SN is a modern intravenous immunoglobulin with multiple pathogen elimination steps. This clinical trial in patients with primary immunodeficiency (PID) was designed to evaluate the safety, efficacy, and tolerability of this product in adults and children. Methods: Forty-four patients with PID were treated with IVIG-SN for 12 months. IgG trough levels and pharmacokinetics of IVIG-SN were evaluated as well as efficacy and safety according to standard FDA guidelines. Results: Overall, a total of 572 IVIG-SN infusions were administered according to either a 21- or a 28-day schedule. IgG trough levels during the treatment period ranged from 823.00 to 902.77 mg/dL, respectively, and half-life in serum of the administered IgG was 43.45 ± 30.25 days. There were no deaths and no adverse events leading to withdrawal from the study. Of all infusions administered, only 137 (24%) were temporally associated with an adverse event (AE). The upper bound for the 95% CI for the frequency of infusions temporally associated with an AE was 29.2%. Drug-related AEs were predominantly mild, and there were no acute serious bacterial infections during the study. Efficacy was also demonstrated by low rates of missed work, school, or daycare days (mean 2.6 days); unscheduled visits to physicians (mean 1.7); and therapeutic antibiotic use (mean 15 days). Conclusion: IVIG-SN is effective in preventing infections and is safe and well tolerated. Statement of novelty: This efficacy and toxicity trial was conducted using a new IVIG preparation.

Prophylactic antibiotic use in ENT surgery

Surgical antibiotic prophylaxis (SAP) is defined as the administration of an antimicrobial agent prior to contamination in previously sterile spaces and fluid. SAP should not be confused with the therapeutic use of antibiotics. There are a growing number of studies with the goal of answering the question which patients benefit most from SAP during which specific surgical procedure. However, in the specific surgical field of head and neck surgery and otolaryngological surgery, there are only a few guidelines answering that question for specific procedures. The aim of this study was to analyze the evidence found in the literature and to develop a standard operating procedure, which specifically addresses head and neck and otolaryngeal surgical procedures.

Transrectal ultrasound-guided biopsy sepsis and the rise in carbapenem antibiotic use.

This study sought to determine the number of hospital admissions for sepsis following transrectal ultrasound-guided (TRUS) biopsy, and the rate of both prophylactic and therapeutic use of carbapenem antibiotics for TRUS biopsy, at a single institution. A retrospective review of prospectively collected data from the medical records electronic database of Cabrini Health, a private metropolitan hospital, was queried for coding of admissions under any admitting urologist for sepsis and prostate-related infections from 2009 to 2012. Records were examined for whether a TRUS biopsy had been performed within 14 days prior and if a therapeutic carbapenem was required. The database also queried the use of carbapenems as prophylaxis in patients undergoing TRUS biopsy. Of the 63 admissions for TRUS biopsy sepsis, multi-drug-resistant organisms were isolated from 26 (41%). Twenty-three admissions were from the 1937 patients who underwent a TRUS biopsy at Cabrini (a sepsis rate of 1.2%) and 40 were following TRUS biopsies at other centres. Thirty-seven (58.7%) patients received therapeutic carbapenems either empirically, or after culture results. Of the 1937 Cabrini TRUS biopsy patients, 154 (8%) were given a carbapenem as prophylaxis, with a rapid increase in prophylactic use over the 4 years studied from 0.25% to 13%. This study did not show evidence of an increasing rate of hospital admissions for TRUS biopsy sepsis at this institution. However, there was a dramatic uptake in prophylactic administration of carbapenems. Increasing carbapenem use may contribute to development of carbapenem-resistant bacteria. Alternative methods of prostate biopsy that avoid sepsis should be considered.

Early-life antibiotic use is associated with wheezing among children with high atopic risk: a prospective European study

Background: Little is known about the relationship between antibiotic use and asthma in the children with a higher risk of allergic sensitization. We examine the association between the use of specific therapeutic antibiotics in the first year of life and development of wheezing by 36 months among children with a higher risk of allergic sensitization. Methods: A multi-center prospective cohort study was conducted among children at high risk for allergic sensitization. A validated questionnaire was used to prospectively collect information on antibiotic use and potential risk factors for wheezing from parents or guardians of 606 children from three European countries at 6, 12, 24 and 36 months of age. Multivariate linear and logistic regression models were used to adjust for potential confounders and effect modifiers and to estimate the association of antibiotic use with the development of early childhood wheezing. Results: Of the antibiotics assessed, only macrolide use in the first year of life was associated with increasing risk for wheezing by 36 months, after adjusting for gender, socioeconomic status, breast feeding >6 months, tobacco smoke exposure, family history of asthma, and respiratory infection (RR = 1.09; 95% CI 1.05–1.13). To avoid a bias by indication, we analyzed children with and without respiratory infection separately. Similar associations were observed for macrolides use in children who had no respiratory infection. Conclusions: In European children with a familial risk for allergic sensitization, we found a positive association between macrolide use in the first year of life and wheezing until 36 months old which was independent of the effect of respiratory infection.

Combining flagellin and human β-defensin-3 to combat bacterial infections.

The discovery and therapeutic use of antibiotics made a major contribution to the reduction of human morbidity and mortality. However, the growing resistance to antibiotics has become a matter of huge concern. In this study we aimed to develop an innovative approach to treat bacterial infections utilizing two components: the human antibacterial peptide β-defensin-3 (BD3) and the bacterial protein flagellin (F). This combination was designed to provide an efficient weapon against bacterial infections with the peptide killing the bacteria directly, while the flagellin protein triggers the immune system and acts against bacteria escaping from the peptide’s action. We designed, expressed and purified the fusion protein flagellin BD3 (FBD3) and its two components, the F protein and the native BD3 peptide. FBD3 fusion protein and native BD3 peptide had antibacterial activity in vitro against various bacterial strains. FBD3 and F proteins could also recognize their receptor expressed on target cells and stimulated secretion of IL-8. In addition, F and FBD3 proteins had a partial protective effect in mice infected by pathogenic Escherichia coli bacteria that cause a lethal disease. Moreover, we were able to show partial protection of mice infected with E. coli using a flagellin sequence from Salmonella. We also explored flagellin’s basic mechanisms of action, focusing on its effects on CD4+ T cells from healthy donors. We found that F stimulation caused an increase in the mRNA levels of the Th1 response cytokines IL12A and IFNγ. In addition, F stimulation affected its own receptor.

Antibiotics for treatment of infections by methicillin-resistant Staphylococcus aureus (MRSA)

Over the last 50 years methicillin-resistant S. aureus (MRSA) spread globally. Vancomycin is still the most recommended antibiotic for MRSA-infections. Teicoplanin is an alternative glycopeptide with longer elimination half-life. Telavancin is a more recently developed derivative of vancomycin with similar clinical efficacy as vancomycin. It is not recommended for treatment of patients with renal insufficiency. Nephrotoxicity limits the therapeutic use of glycopeptide antibiotics. The oxazolidinone linezolid exhibits similar to superior therapeutic efficacy. Hematologic controls are necessary during treatment with this antibacterial agent. Neurotoxic effects have been observed mainly in patients who received prolonged linezolid treatment. Attention must be paid to possible interactions with concomitantly given drugs acting on the serotonergic system. New therapeutic options arise with ceftaroline, the first β-lactam antibiotic with activity against MRSA. However, controlled clinical trials with pulmonary MRSA infections have not been conducted with ceftaroline. Daptomycin, a lipopeptide, and tigecycline, a glycylcyclin are active in vitro against MRSA as well, but are also not indicated in pulmonary MRSA infections. These antibiotics show in an exemplary manner that antibacterial activity in vitro is an important prerequisite, but relevant data for a therapeutic decision should be derived from randomized controlled clinical double-blind trials.

Why anti-inflammatory compounds are the solution for the problem with in feed antibiotics

There is increasing pressure to reduce the prophylactic and therapeutic use of antibiotics in animal production based on the fear for inducing bacterial resistance. Antibiotics are very cost effective promoters of growth and health in production animals. Therefore, farmers would only be willing to reduce antibiotics if effective alternatives are available. The search for alternatives is hampered by misconceptions about the exact physiological mechanisms behind growth promotion by antibiotic growth promoters (AGP). Hitherto, they were attributed to their antibiotic properties. This is highly unlikely for various reasons, the main one being the subtherapeutic concentrations used. AGP work much more likely by direct inhibition of the intestinal postprandial inflammatory response. This implies that alternatives to antimicrobial growth promoters should be non-antibiotic anti-inflammatory compounds, which also removes the fear for inducing bacterial resistance. Because of public resistance against the perceived...

Nosocomial Wound Infection amongst Post Operative Patients and their Antibiograms at Tertiary Care Hospital in India

Nosocomial infection constitutes a major public health problem worldwide. Increasing antibiotic resistance of pathogens associated with nosocomial infections also becomes a major therapeutic challenge for physicians. Thus, the aim of this study was to identify post operative bacterial infections in the patients developing surgical site infections at a tertiary University hospital in North India during July 2013 to Dec 2013.Methods: One hundred and ninety six swabs/pus specimens from various types of surgical sites suspected to be infected onclinical grounds were processed, by standard methods and antibiotic susceptibility testing of all the isolates was done by usingKirby Baur disc diffusion technique.Results: Of the one hundred and fifty-eight organisms isolated, the most common was Staphylococcus aureus (27.8 %), followedby Escherchia coli (24.05 %), Klebsiella pneumoniae (13.29 %), Pseudomonas aeruginosa (6.32%), Klebsiella oxytoca (5%),Enterococcus (5.6%) and other miscellaneous gram negative rods (9.4%) and Streptococcus pyogenes (1.30%). About 50% of theStaphylococcus aureus isolates were found to be methicillin resistant. In case of Escherichia coli, more than one-third of the isolates were found to be ESBL producers. The resistance to third generation cephalosporins and the quinolone ciprofloxacin was also quite high. Other isolates also showed a very high level of antibiotic resistance.Conclusion: In addition to the economic burden for antibiotic treatment, such infections for multi-resistant organisms are a serious threat to our surgical patients. To prevent these happenings, there is ar urgent need to adopt basic principles of asepsis and sterilization and to make judicious use of prophylactic and therapeutic antibiotics and determine current antimicrobial resistance to commonly prescribed drugs.Keywords: Wound infection; microorganisms; anti-microbial sensitivity

The effect of production system and management practices on the environmental impact, quality and safety of milk and dairy products

There is an increasing trend to label milk and dairy products according to production system, absence of certain feed additives and non-use of specific technologies. These claims include the practice of organic farming, the absence of ionophore antibiotics and recombinant bovine somatotropin (r-bST) free milk. Absence-claim labels may imply to some consumers that certain milk is safer and more nutritious than other milk. Milk from r-bST supplemented cows is completely safe for human consumption, since bST is a protein, which is digested like other animal and plant proteins, it is species specific, and most bST in milk is denaturated by pasteurization. Fears of higher insulin growth factor 1 (IGF-1) levels in r-bST milk are unfounded, since these are insignificant compared with the daily secretion of IGF-1 in human saliva and gastro-intestinal secretions. r-bST does not affect milk composition. All milk (i.e. conventional, r-bST free and organic) is compositionally similar, and all milk is wholesome. Various studies have also confirmed that r-bST does not affect milk flavour or manufacturing characteristics that are important during the production of processed dairy foods such as cheese or yoghurt. There is no pathway for ionophore antibiotics from feed to milk and there is no scientific basis for concerns that these additives can give rise to transmissible resistance factors that may compromise the therapeutic use of antibiotics in humans. Organic farming is recognized as a possible way forward to improve sustainability in agriculture. However, it typically requires more resources and produces less food, which currently makes it less profitable and a questionable solution to meeting the world’s growing food supply needs. Improving productive efficiency by using technologies is currently the most logical approach to mitigating the environmental impact of the dairy herd. The potential of r-bST and feed additives such as ionophore antibiotics to reduce greenhouse gas emissions should be recognized and implemented where applicable.Keywords: Dairy production systems, r-bST, ionophores, organic milk

Risk factors for surgical site infection in Japanese patients with ulcerative colitis: a multicenter prospective study

A prospective, multicenter, observational study was performed to investigate the risk factors of surgical site infection (SSI) in patients with ulcerative colitis (UC). From 2009 to 2010, perioperative clinicopathological data were collected from patients who had undergone surgery for UC within the research period, for up to 6 consecutive months in 13 hospitals in Japan. The primary outcome was the development of SSI. A total of 195 patients with UC who underwent colorectal surgery were enrolled. SSI was diagnosed in 38 (19.5 %) patients, in the form of incisional infection in 23 (11.8 %), organ/space infection in 16 (8.2 %), and both in 1 (0.5 %). There were no significant risk factors associated with an increased risk of development of incisional SSI. An American Society of Anesthesiologists physical status of ≥ 3 was indicated as the only significant risk factor for organ/space SSI (P = 0.02) compared with other factors, such as a neutrophil count of >100 × 10(2)/mm(3), albumin level of <3.5 g/dl, perioperative packed red blood cell transfusion, fair or poor colonic cleanliness, and therapeutic use of antibiotics. Poor general physical status was the significant independent risk factor for organ/space SSI in patients with UC in Japan.

Early-life antibiotic use is associated with wheezing among children with high atopic risk: a prospective European study

Background: Deliberate antibiotic use (AU) in early life may contribute to asthma. Although a number of published studies have tested AU in conjuction with the hygiene hypothesis, the results have been conflicting and little is known about the relationship between AU and asthma in the children with high atopic risk. Aims: To examine the association between the use of specific therapeutic antibiotics in the first year of life and wheezing by 36 months among high atopic risk children. Methods: A multi-center prospective cohort study was conducted among children at high-risk for atopic sensitization. A validated questionnaire was used to prospectively collect information on antibiotic use and potential risk factors for wheezing from parents or guardians of 606 children from 3 European countries at 6, 12, 24, and 36 months of age. Linear logistic regression model was used to adjust for potential confounders and estimate odds ratios (OR) with 95% confidence interval (CL) associated with antibiotic use for development of wheezing Results: Only macrolides’ use in the first year of life was associated with increasing risk for wheezing, after adjusting for gender, socioeconomic status, breast feeding, tobacco smoke exposure of the infants, family history of asthma, and respiratory infection (OR=3.24; 95%CI 1.47-7.30). Among the children with respiratory infection, similar associations were observed for macrolides use (OR=3.42; 95%CI 1.46-8.01) and lower respiratory tract infection (OR=4.60; 95%CI 2.19-9.66). Conclusions: In European children with a familial risk for allergic disease, we found a positive association between macrolides use in the first year of life and wheezing until 36 months. Key words: antibiotic use, wheezing, prospective cohort

Management of patients with infective endocarditis by a multidisciplinary team approach

Even in the modern era of advanced diagnostic imaging, improved antibiotic therapy and potentially curative surgery, infective endocarditis remains a serious disease with high rates of morbidity and mortality. Reasons for such a persistently poor outcome may be represented by the changing epidemiology and microbiology, with new groups of patients at risk and new and more aggressive microorganisms. However, the inadequate use of both diagnostic (blood cultures and echocardiography) and therapeutic (antibiotics and surgery) means can influence the generally delayed diagnosis and poor prognosis seen in patients with infective endocarditis. We tried to identify the critical points in the management of patients with infective endocarditis and to elaborate a formal multidisciplinary approach based on the strict collaboration of specialists in infectious diseases, microbiology, cardiology and cardiac surgery. We hypothesized that this approach could increase the adherence to the published guidelines, and could represent a means to improve the outcome of patients with infective endocarditis.

Randomized controlled trials of antibiotics for neonatal infections: a systematic review

Antibiotics are a key resource for the management of infectious diseases in neonatology and their evaluation is particularly challenging. We reviewed medical literature to assess the characteristics and quality of randomized controlled trials on antibiotics in neonatal infections. We performed a systematic search of PubMed, Embase and the Cochrane Library from January 1995 to March 2010. Bibliographies of relevant articles were also hand-searched. We included all randomized controlled trials that involved neonates and evaluated the use of an antibiotic agent in the context of a neonatal infectious disease. Methodological quality was evaluated using the Jadad scale and the Cochrane Risk of Bias Tool. Two reviewers independently assessed studies for inclusion and evaluated methodological quality. A total of 35 randomized controlled trials were evaluated. The majority were conducted in a single hospital institution, without funding. Median sample size was 63 (34-103) participants. The most frequently evaluated antibiotic was gentamicin. Respectively, 18 (51%) and 17 (49%) trials evaluated the therapeutic or prophylactic use of antibiotics in various neonatal infections. Overall, the methodological quality was poor and did not improve over the years. Risk of bias was high in 66% of the trials. Design and reporting of randomized controlled trials of antibacterial agents in neonates should be improved. Nevertheless, the necessity of implementing such trials when antibacterial efficacy has already been established in other age groups may be questioned and different methods of evaluation should be further developed.

Clinical outcomes and risk factors of post-polypectomy coagulation syndrome: a multicenter, retrospective, case-control study

Post-polypectomy coagulation syndrome (PPCS) is a well known complication of colonoscopic polypectomy. However, no previous studies have reported on the clinical outcomes or risk factors of PPCS. The aim of the current study was to analyze the clinical outcomes and risk factors of PPCS developing after a colonoscopic polypectomy. Data for all patients who underwent colonoscopic polypectomies and required hospitalization in nine university hospitals were analyzed retrospectively. The incidence, clinicopathological characteristics, and clinical outcomes of PPCS cases were examined. Additionally, patients who developed PPCS were compared with controls who were matched by age and sex, in order to assess for possible risk factors. The rate of PPCS that required hospitalization after colonoscopic polypectomy was 0.7/1000. All patients with PPCS were treated medically without the need for surgical interventions. The median durations of therapeutic fasting, hospitalization, and antibiotic use were 3 days, 5.5 days, and 7 days, respectively. The rates of major PPCS and mortality were 2.9 % and 0 %, respectively. On multivariate analysis, hypertension (OR = 3.023, 95 %CI 1.034 - 8.832), large lesion size (OR = 2.855, 95 %CI 1.027 - 7.937), and non-polypoid configuration (OR = 3.332, 95 %CI 1.029 - 10.791) were found to be independent risk factors related to the development of PPCS. In this study, the rates of major PPCS and mortality were only 2.9 % and 0 %, respectively. Hypertension, large lesion size, and non-polypoid configuration of the lesion were independently associated with PPCS. Therefore, patients may be reassured by the excellent prognosis of PPCS, while endoscopists should be especially careful when performing colonoscopic polypectomies in patients with hypertension or large and non-polypoid lesions.

Infective endocarditis caused by multidrug-resistant Streptococcus mitis in a combined immunocompromised patient: an autopsy case report

An autopsy case of infective endocarditis caused by multidrug-resistant Streptococcus mitis was described in a patient with a combination of factors that compromised immune status, including autoimmune hemolytic anemia, post-splenectomy state, prolonged steroid treatment, and IgA deficiency. The isolated S. mitis strain from blood culture was broadly resistant to penicillin, cephalosporins, carbapenem, macrolides, and fluoroquinolone. Recurrent episodes of bacterial infections and therapeutic use of several antibiotics may underlie the development of multidrug resistance for S. mitis. Because clinically isolated S. mitis strains from chronically immunocompromised patients have become resistant to a wide spectrum of antibiotics, appropriate antibiotic regimens should be selected when treating invasive S. mitis infections in these compromised patients.

Phenotypic and Molecular Antibiotic Resistance Profile ofEnterococcus faecalisandEnterococcus faeciumIsolated from Different Traditional Fermented Foods

A collection of 55 enterococci (41 Enterococcus faecium and 14 E. faecalis strains) isolated from various traditional fermented foodstuffs of both animal and vegetable origins, and water was evaluated for resistance against 15 antibiotics. Lower incidence of resistance was observed with gentamicin, ampicillin, penicillin and teicoplanin. However, a high incidence of antibiotic resistance was detected for rifampicin (12 out of 14 of isolates), ciprofloxacin (9/14), and quinupristin/dalfopristin (8/14) in E. faecalis strains. Enterococcus faecium isolates were resistant to rifampicin (25/41), ciprofloxacin (23/41), erythromycin (18/41), levofloxacin (16/41), and nitrofurantoin (15/41). One Enterococcus faecalis and two E. faecium strains were resistant to vancomycin (MIC>16 μg/mL). Among 55 isolates, 27 (19 E. faecium and eight E. faecalis) were resistant to at least three antibiotics. High level of multidrug resistance to clinically important antibiotics was detected in E. faecalis strains (57% of E. faecalis versus 46% of E. faecium), which showed resistance to six to seven antibiotics, especially those isolated from foods of animal origin. So, it is necessary to re-evaluate the use of therapeutic antibiotics in stock farms at both regional and international levels due to the high number of multiple resistant (MR) bacteria. Fifty-six MR E. faecalis and E. faecium strains selected from this and previous studies (Valenzuela et al., 2008, 2010) were screened by polymerase chain reaction for antibiotic resistance genes, revealing the presence of tet(L), tet(M), ermB, cat, efrA, efrB, mphA, or msrA/B genes. The ABC Multidrug Efflux Pump EfrAB was detected in 96% of E. faecalis strains and also in 13% of E. faecium strains; this is the first report describing EfrAB in this enterococcal species. The efflux pump-associated msrA/B gene was detected in 66.66% of E. faecium strains, but not in E. faecalis strains.

Characterization and Optimization of an Anti-Aeromonas Bacteriocin Produced by Lactococcus lactis Isolated from Hukuti Maas, an Indigenous Fermented Fish Product

Lactococcus lactis ssp. lactis HKBT-9 strain isolated from hukuti maas, produced a bacteriocin active against foodborne pathogens with specificity toward Aeromonas spp. The bacteriocin produced was sensitive to proteolytic enzymes, stable between pH 2.0 and 10.0, and was thermoresistant (15 min at 121C). Proteinase K, pepsin, ethylenediaminetetraacetic acid and urea strongly inhibited bacteriocin production indicating that the active component of bacteriocin was proteinaceous. Among detergents, sodium dodecyl sulphate, Tween 80 and Tween 20 enhanced bacteriocin activity, which may be due to nondenaturation or its association with other molecules, with a stabilizing effect on bacteriocin activity. Enzymes like α-amylase; DNase and RNase showed slightly increased bacteriocin activity. Maximum activity (2,844 arbitrary units [AU]/mL) against Aeromonas hydrophila was observed and remained for at least 24 h. Optimization using response surface methodology resulted in increased bacteriocin production of 3,591.09 AU/mL at 37.36C, pH 6.63 and inoculum size of 1.53 optical density. Practical Applications Bacteriocins of lactic acid bacteria have been found to kill or inhibit the growth of foodborne pathogens and spoilage microflora, and hence, can be used as natural preservatives in the production of foods with enhanced shelf life and/or safety. With the emergence of antibiotic-resistant gram-positive pathogenic bacteria, the possibility of bacteriocins as supplements or replacements for antibiotics for therapeutic use is also being considered. Of all the antimicrobial peptides, very few have been used as preservatives in the food industry and/or as antibiotic substances in medicine. In the present study, characterization and optimization of an anti-Aeromonas bacteriocin produced by Lactococcus lactis isolated from hukuti maas was attempted, which could be used a potential food biopreservative.

Crystal Structures of Pseudomonas aeruginosa GIM-1: Active-Site Plasticity in Metallo-β-Lactamases

Metallo-β-lactamases (MBLs) have rapidly disseminated worldwide among clinically important Gram-negative bacteria and have challenged the therapeutic use of β-lactam antibiotics, particularly carbapenems. The bla(GIM-1) gene, encoding one such enzyme, was first discovered in a Pseudomonas aeruginosa isolate from 2002 and has more recently been reported in Enterobacteriaceae. Here, we present crystal structures of GIM-1 in the apo-zinc (metal-free), mono-zinc (where Cys221 was found to be oxidized), and di-zinc forms, providing nine independently refined views of the enzyme. GIM-1 is distinguished from related MBLs in possessing a narrower active-site groove defined by aromatic side chains (Trp228 and Tyr233) at positions normally occupied by hydrophilic residues in other MBLs. Our structures reveal considerable flexibility in two loops (loop 1, residues 60 to 66; loop 2, residues 223 to 242) adjacent to the active site, with open and closed conformations defined by alternative hydrogen-bonding patterns involving Trp228. We suggest that this capacity for rearrangement permits GIM-1 to hydrolyze a wide range of β-lactams in spite of possessing a more constrained active site. Our results highlight the structural diversity within the MBL enzyme family.