Among 39 carbapenem-resistant Enterobacteriaceae (2.7% overall; Escherichia coli , Enterobacter cloacae , and Klebsiella pneumoniae strains) isolated in 2006 and 2007 in India, 15 strains carried bla _NDM-1 and 10 harbored a gene encoding a variant of the carbapenemase OXA-48, named bla _OXA-181 . One E. cloacae strain harbored bla _VIM-6 , and one K. pneumoniae strain carrying bla _OXA-181 also possessed bla _VIM-5 . Multiple pulsed-field gel electrophoresis patterns and clonal dissemination within and among sites were observed. Isolates producing NDM-1 were disseminated in Indian health care facilities as early as 2006.

Acinetobacter baumannii-calcoaceticus complex is the most commonly identified species in the genus Acinetobacter and it accounts for a large percentage of nosocomial infections, including bacteremia, pneumonia, and infections of the skin and urinary tract. A few key clones of A. baumannii-calcoaceticus are currently responsible for the dissemination of these organisms worldwide. Unfortunately, multidrug resistance is a common trait among these clones due to their unrivalled adaptive nature. A. baumannii-calcoaceticus isolates can accumulate resistance traits by a plethora of mechanisms, including horizontal gene transfer, natural transformation, acquisition of mutations, and mobilization of genetic elements that modulate expression of intrinsic and acquired genes.

Community-onset (CO) candidemia, defined as a positive blood culture taken at or within 2 days of hospital admission, represents a distinct clinical entity associated with substantial morbidity and mortality. Reference MIC results from the SENTRY Antimicrobial Surveillance Program (2008-2009) were analyzed to compare the antifungal resistance patterns and species distributions from patients with CO and nosocomial bloodstream infections (BSI) in 79 medical centers. Among 1,354 episodes of BSI, 494 (36.5%) were classified as CO and 860 (63.5%) as nosocomial in origin. More than 95% of the isolates from both BSI types were contributed by Candida albicans (48.4%), C. glabrata (18.2%), C. parapsilosis (17.1%), C. tropicalis (10.6%), and C. krusei (2.0%). C. albicans was more common in CO BSI (51.0%) than nosocomial BSI (46.9%), whereas C. parapsilosis and C. krusei were more common in nosocomial BSIs (18.1 and 2.7%, respectively) than in CO BSIs (15.4 and 0.8%, respectively). C. glabrata and C. tropicalis were comparable in both CO (18.4 and 10.5%, respectively) and nosocomial (18.1 and 10.6%, respectively) episodes. Resistance to azoles (fluconazole, posaconazole, and voriconazole) and echinocandins (anidulafungin, caspofungin, and micafungin) was uncommon (<5%) in CO BSI using recently established Clinical and Laboratory Standards Institute breakpoint criteria. Resistance to echinocandins (anidulafungin [3.8%], caspofungin [5.1%], and micafungin [3.2%]) and azoles (fluconazole [7.7%], posaconazole [5.1%], and voriconazole [6.4%]) was most prevalent among nosocomial BSI isolates of C. glabrata . CO candidemia is not uncommon and appears to be increasing worldwide due to changing health care practices. Although resistance to the azoles and echinocandins remains uncommon among CO isolates, we demonstrate the emergence of nosocomial occurrences of C. glabrata expressing resistance to both monitored classes of antifungal agents.

Antifungal testing results from the SENTRY Antimicrobial Surveillance Program (2008 to 2009) were analyzed for regional variations of invasive Candida species infections. Among 2,085 cases from the Asian-Pacific (APAC) (51 cases), Latin American (LAM) (348 cases), European (EU) (750 cases), and North American (NAM) (936 cases) regions, Candida albicans predominated (48.4%), followed by C. glabrata (18.0%), C. parapsilosis (17.2%), C. tropicalis (10.5%), and C. krusei (1.9%). Resistance to echinocandins (anidulafungin [2.4%] and micafungin [1.9%]) and azoles (3.5 to 5.6%) was most prevalent among C. glabrata isolates, as determined using recently established CLSI breakpoint criteria. C. glabrata isolates were more common in NAM (23.5%), and C. albicans isolates were more common in APAC (56.9%), with C. parapsilosis (25.6%) and C. tropicalis (17.0%) being more prominent in LAM. Emerging resistance patterns among C. glabrata cases in NAM require focused surveillance.

To evaluate the genetic relatedness and carbapenem resistance mechanisms among carbapenem-non-susceptible Pseudomonas aeruginosa collected during 2009–11 in 14 European and Mediterranean countries. Doripenem-non-susceptible (MIC >2 mg/L) isolates were tested for susceptibility to imipenem, meropenem, doripenem, aztreonam, ceftazidime and cefepime with and without phenyl-arginine-β-naphthylamide (PAβN) (efflux inhibitor) and/or cloxacillin (AmpC inhibitor). Carbapenemase screening was performed by PCR and sequencing. Expression of chromosomal ampC, mexA, mexC, mexE and mexX was determined by quantitative real-time PCR using P. aeruginosa PAO1 or a group of susceptible isolates as baseline. Clonality was evaluated by PFGE and multilocus sequence typing. Among 529 (25.6% overall) carbapenem-non-susceptible P. aeruginosa, 106 were positive for metallo-β-lactamase (MβL) genes encoding VIM-2 (76 strains), VIM-4 (14), VIM-1 (7) and VIM-5 (5). IMP-15 and three new MβLs (IMP-33, VIM-36 and VIM-37) were detected in one strain each. An increasing prevalence of MβL producers was noted in 2011 (30.6%) compared with previous years (13.4% and 12.3% in 2009 and 2010, respectively). Isolates displayed high genetic diversity, with 401 unique profiles detected. CC235 and ST111 were detected among MβL-producing clusters. The PAβN/cloxacillin effect ranged from 90.0% to 56.5%/from 1.3% to 21.2%. OprD decrease/loss was the most prevalent intrinsic mechanism and was detected among 94.9% of the P. aeruginosa, followed by AmpC (44.4%) and MexAB-OprM (20.1%). When using the susceptible group of isolates as baseline, MexAB-OprM became as prevalent as OprD decrease/loss. Increasing MβL prevalence is worrisome in various European countries; however, intrinsic resistance mechanisms in a highly genetically diverse population of carbapenem-non-susceptible P. aeruginosa are probably a matter for greater concern in these countries.

Escherichia coli (328 isolates), Klebsiella pneumoniae (296), Klebsiella oxytoca (44), and Proteus mirabilis (33) isolates collected during 2012 from the nine U.S. census regions and displaying extended-spectrum-β-lactamase (ESBL) phenotypes were evaluated for the presence of β-lactamase genes, and antimicrobial susceptibility profiles were analyzed. The highest ESBL rates were noted for K. pneumoniae (16.0%, versus 4.8 to 11.9% for the other species) and in the Mid-Atlantic and West South Central census regions. CTX-M group 1 (including CTX-M-15) was detected in 303 strains and was widespread throughout the United States but was more prevalent in the West South Central, Mid-Atlantic, and East North Central regions. KPC producers (118 strains [112 K. pneumoniae strains]) were detected in all regions and were most frequent in the Mid-Atlantic region (58 strains). Thirteen KPC producers also carried bla _CTX-M . SHV genes encoding ESBL activity were detected among 176 isolates. Other β-lactamase genes observed were CTX-M group 9 (72 isolates), FOX (10), TEM ESBL (9), DHA (7), CTX-M group 2 (3), NDM-1 (2 [Colorado]), and CTX-M groups 8 and 25 (1). Additionally, 62.9% of isolates carried ≥2 β-lactamase genes. KPC producers were highly resistant to multiple agents, but ceftazidime-avibactam (MIC _50/90 , 0.5/2 μg/ml) and tigecycline (MIC _50/90 , 0.5/1 μg/ml) were the most active agents tested. Overall, meropenem (MIC ₅₀ , ≤0.06 μg/ml), ceftazidime-avibactam (MIC ₅₀ , 0.12 to 0.5 μg/ml), and tigecycline (MIC ₅₀ , 0.12 to 2 μg/ml) were the most active antimicrobials when tested against this collection. NDM-1 producers were resistant to all β-lactams tested. The diversity and increasing prevalence of β-lactamase-producing Enterobacteriaceae have been documented, and ceftazidime-avibactam was very active against the vast majority of β-lactamase-producing strains isolated from U.S. hospitals.