A 5-year Surveillance Study on Antimicrobial Resistance of Acinetobacter baumannii Clinical Isolates from a Tertiary Greek Hospital / 감염과화학요법

BACKGROUND: Acinetobacter baumannii has emerged as a major cause of nosocomial outbreaks. It is particularly associated with nosocomial pneumonia and bloodstream infections in immunocompromised and debilitated patients with serious underlying pathologies. Over the last two decades, a remarkable rise in the rates of multidrug resistance to most antimicrobial agents that are active against A. baumannii has been noted worldwide. We evaluated the rates of antimicrobial resistance and changes in resistance over a 5-year period (2010–2014) in A. baumannii strains isolated from hospitalized patients in a tertiary Greek hospital. MATERIALS AND METHODS: Identification of A. baumannii was performed by standard biochemical methods and the Vitek 2 automated system, which was also used for susceptibility testing against 18 antibiotics: ampicillin/sulbactam, ticarcillin, ticarcillin/clavulanic acid, piperacillin, piperacillin/tazobactam, cefotaxime, ceftazidime, cefepime, imipenem, meropenem, gentamicin, amikacin, tobramycin, ciprofloxacin, tetracycline, tigecycline, trimethoprim/sulfamethoxazole, and colistin. Interpretation of susceptibility results was based on the Clinical and Laboratory Standards Institute criteria, except for tigecycline, for which the Food and Drug Administration breakpoints were applied. Multidrug resistance was defined as resistance to ≥3 classes of antimicrobial agents. RESULTS: Overall 914 clinical isolates of A. baumannii were recovered from the intensive care unit (ICU) (n = 493), and medical (n = 252) and surgical (n = 169) wards. Only 4.9% of these isolates were fully susceptible to the antimicrobials tested, while 92.89% of them were multidrug resistant (MDR), i.e., resistant to ≥3 classes of antibiotics. ICU isolates were the most resistant followed by isolates from surgical and medical wards. The most effective antimicrobial agents were, in descending order: colistin, amikacin, trimethoprim/sulfamethoxazole, tigecycline, and tobramycin. Nevertheless, with the exception of colistin, no antibiotic was associated with a susceptibility rate >40% for the entire study period. The most common phenotype showed resistance against ampicillin/sulbactam, cephalosporins, carbapenems, aminoglycosides, ciprofloxacin, and tigecycline. An extremely concerning increase in colistin-resistant isolates (7.9%) was noted in 2014, the most recent study year. CONCLUSION: The vast majority of A. baumannii clinical isolates in our hospital are MDR. The remaining therapeutic options for critically ill patients who suffer from MDR A. baumannii infections are severely limited, with A. baumannii beginning to develop resistance even against colistin. Scrupulous application of infection control practices should be implemented in every hospital unit. Lastly, given the lack of available therapeutic options for MDR A. baumannii infections, well-controlled clinical trials of combinations of existing antibiotics are clearly needed.

Epidemiological Relationship of Enterotoxigenic Escherichia coli and Enteroaggregative E. coli Isolated from Patients with Diarrhea in Seoul

Of total 1,438 specimens of patients with diarrhea in Seoul, 2011, 217 samples (15%) were found pathogenic Escherichia coli that included 192 strains (89%) of enterotoxigenic E. coli (ETEC) and enteroaggregative E. coli (EAEC). The highest isolation rate for ETEC and EAEC was found in August and September. Sixty two pathogenic E. coli strains (34 ETEC and 28 EAEC strains) were selected from 175 strains (94 ETEC and 81 EAEC strains) isolated in August and September. Of 94 strains characterized for ETEC phenotype, 76 (81%) expressed heat-stable toxin (ST) only. Antimicrobial susceptibility test was carried out by using sixteen types of antibiotics. A high level of antimicrobial resistance to tetracycline (57%), ampicillin and ticarcillin (54%) was observed among EAEC isolates while the highest resistance rate of ETEC was found for nalidixic acid (47%), followed by tetracycline (32%). As to the antimicrobial susceptibility test, EAEC showed the complicated multi-drug resistant patterns in which the resistance was higher than ETEC. Pulsed-field gel electrophoresis (PFGE) was carried out to examine the genetic relatedness among ETEC and EAEC isolates. Except for 11 strains, 51 strains were divided by eight pulsotypes. In PFGE analysis, isolates from foodborne disease outbreaks in August and September 2011 showed close relation.

The Laboratory Diagnosis of Melioidosis in a Korean Patient

Burkholderia pseudomallei is a gram-negative opportunistic intracellular pathogen that causes an acute and fatal septicemic melioidosis in humans. The organism is mainly found in Southeastern Asia and Northern Australia. Recently, we encountered a case of melioidosis in a Korean patient and performed the laboratory diagnosis of melioidosis. As a result, a gram negative bacterium was isolated from a melioidosis patient, and it was identified as B. pseudomallei on DNA sequencing of 16S ribosomal RNA with 99.9% homology and biochemical examination of VITEK gram-negative identification card. Also, DNA from cultured bacteria was tested in multiplex PCR, a 245 bp fragment amplified from the metalloprotease gene and a fragment of variable size ranging from 400~700 bp resulting from amplification of the 10 bp repetitive element for B. pseudomallei were confirmed after electrophoresis. The bacterium was sensitive to ceftazidime, imipenem and meropenem but resistant to ticarcillin. So far, there are no domestic cases of melioidosis in Korea, however, due to the increase in international travelers, the incidence of melioidosis is likely to increase. We report a recent case of melioidosis in a Korean patient.

Identification of Shiga Toxin-producing E. coli Isolated from Diarrhea Patients and Cattle in Gwangju Area, Korea

Shiga toxin-producing Escherichia coli (STEC) strains are commensal bacteria in cattle and cause food borne disease in human. We analyzed the isolation rate of STEC in stool specimens of patients with diarrhea and in fecal samples of cattle in Gwangju, Korea. STEC strains were detected from 33 (0.19%) out of 17,148 patients with diarrhea while there has been a progressive increase in the incidence rate from 0.07% in 2004 to 0.33% in 2008. We investigated serotypes, shiga toxin genes, and antimicrobial resistance patterns of the 44 STEC isolates from human and cattle sources. The 33 STEC isolates from human belonged to 14 O serotypes including O157, O26 and O111. The 11 isolates from cattle belonged to 11 O serotypes. PCR detection for stx genes showed that 12 (27.3%) isolates carried stx1 genes, 20 (45.5%) possessed stx2 genes, and 12 (27.3%) carried both stx1 and stx2. Of the 33 STEC isolates from human, 25 strains (76%) were resistant to one or more antibiotics. High level of resistance to tetracycline (73%) was most common, followed by ticarcillin and ampicillin (64%). But none of the 33 isolates from human were resistant to amikacin, cefazolin, cefepime, cefotetan, cefotaxime, ciprofloxacin, or imipenem. The 5 strains (45%) of the 11 isolates from cattle were resistant to at least one or three antibiotics but most of the isolates were sensitive to the 16 antibiotics employed in this survey. In conclusion, toxin types and serotypes of STEC isolated from human and cattle were diverse, and non-O157 STEC was also observed to be a greater proportion of STEC isolates. According to a specific comparison solely based on the toxin types and serotypes, most of the STEC strains isolated from cattle feces in Gwangju, Korea showed characteristics different from those isolated from patients. Therefore, laboratory surveillance is required to detect and carefully monitor the potentially hypervirulent STEC not only in human and cattle but also in other animals.

Sensitivity pattern of gram negative bacilli to three beta-lactam/beta-lactamase inhibitor combinations using the automated API system.

PURPOSE: To evaluate the spectrum of activity of three beta-lactamase inhibitors such as amoxicillin/ clavulanic acid, ticarcillin/ clavulanic acid and piperacillin/ tazobactam in comparison to cephalosporins against gram negative bacilli. METHODS: Gram-negative bacilli isolated from the clinical specimens received in the laboratory were included in the study. Using the API system (bioMiotarieux) during a one-year period, a total of 1,252 Enterobacteriaceae and 385 non-fermenters were evaluated. RESULTS: The percentage resistance of the Enterobacteriaceae isolates was 82.92% to amoxicillin/ clavulanic acid, 58.22% to ticarcillin/clavulanic acid and 22.44% to piperacillin/tazobactam respectively. Pseudomonas aeruginosa showed resistance of 96% to ticarcillin/ clavulanic acid and 61% to piperacillin/ tazobactam and Acinetobacter baumannii showed 49% resistance to ticarcillin/ clavulanic acid and 77% resistance to piperacillin/ tazobactam respectively. The isolates exhibited high resistance to all the generations of cephalosporins and the other groups of antibiotics except carbapenems. CONCLUSIONS: Piperacillin/tazobactam was found to be the most active combination of the three against Enterobacteriaceae and Pseudomonas spp. and ticarcillin/clavulanic acid against Acinetobacter spp. and Stenotrophomonas maltophilia.

Antimicrobial Resistance in Escherichia coli Isolated from Healthy Volunteers of the Community / 대한임상미생물학회지

BACKGROUND: We monitored the prevalence of antimicrobial resistance and the pattern of multiple drug resistance in Escherichia coli isolated from healthy people in the community. METHODS: We performed antimicrobial susceptibility testing on 491 isolates of E. coli from 692 healthy people in Incheon from February to July in 2006. The results were interpreted according to the CLSI guidelines. RESULTS: The highest rate of resistance was observed against tetracycline (46.6%), ampicillin (41.1%), ticarcillin (37.9%), streptomycin (31.0%), and nalidixic acid (23.6%). Twenty six percent of isolates were observed to be resistant to five or more of the antimicrobials tested. CONCLUSION: In order to maintain a low level of antimicrobial use and resistance, the surveillance of antimicrobial resistance in the community would be very important, as it provides epidemical data to set up and control antibiotic guidelines and serves as an early warning for resistance in pathogenic bacteria.

Comparative in vitro activity of beta-lactam/beta-lactamase inhibitor combinations against gram negative bacteria.

BACKGROUND & OBJECTIVE: Currently, the use of beta-lactamase inhibitors in combination with beta-lactam antibiotics represents an effective measure to combat a specific resistance mechanism of beta-lactamase producing organisms. Knowledge about the susceptibility profile of bacteria to different combination agents available is essential to guide appropriate treatment of severe infections in hospitalized patients. The present study compares the in vitro activity of three commercially available beta-lactam/beta-lactamase inhibitor combinations (piperacillin/tazobactam, cefoperazone/sulbactam, ticarcillin/clavulanic acid) against beta-lactamase producing gram negative bacteria in a tertiary care hospital in north India. METHODS: A total of 9004 consecutively isolated extended spectrum beta-lactamase (ESBL) producing gram negative bacteria isolated from various clinical samples from patients admitted to the All India Institute of Medical Sciences, New Delhi, from September 2003 to August 2004 were included in the study. These isolates were screened for ESBL production by the inhibitor based test recommended by the National Committee for Clinical Laboratory Standards (NCCLS). Antibiotic susceptibility testing was carried out by disc diffusion method as per NCCLS guidelines. RESULTS: Of the 9004 isolates tested, 3232 (35.89%) were sensitive and 568 (6.31%) were resistant to all three combination agents, and rest 5204 (57.80%) were resistant to at least one of the combinations. Susceptibility to piperacillin/tazobactam, cefoperazone/sulbactam, and ticarcillin/clavulanic acid was 81.37, 76.06 and 45.48 per cent respectively. Piperacillin/tazobactam exhibited significantly (P<0.05) greater antimicrobial activity against Pseudomonas spp., Escherichia coli and Klebsiella spp. compared to cefoperazone/sulbactam. INTERPRETATION & CONCLUSION: Overall piperacillin/tazobactam was observed to be the best combination agent followed by cefoperazone/sulbactam in our setting. This difference in activities of these combination agents needs to be evaluated further by ascertaining their efficacy in clinical studies.

Evaluation of ticarcillin/clavulanic acid versus ceftriaxone plus amikacin for fever and neutropenia in pediatric patients with leukemia and lymphoma

BACKGROUND: The empirical use of antibiotic treatments is widely accepted as a means to treat cancer patients in chemotherapy who have fever and neutropenia. Intravenous monotherapy, with broad spectrum antibiotics, of patients with a high risk of complications is a possible alternative. METHODS: We conducted a prospective open-label, randomized study of patients with lymphoma or leukemia who had fever and neutropenia during chemotherapy. Patients received either monotherapy with ticarcillin/clavulanic acid (T) or ceftriaxone plus amikacin (C+A). RESULTS: Seventy patients who presented 136 episodes were evaluated, 68 in each arm of the study. The mean neutrophil counts at admission were 217cells/mm (T) and 201cells/mm (C+A). The mean duration of neutropenia was 8.7 days (T) and 7.6 days (C+A). Treatment was successful without the need for modifications in 71 percent of the episodes in the T group and 81 percent in the C+A group (p=0.23). Treatment was considered to have failed because of death in two episodes (3 percent) in the T group and three episodes (4 percent) in the C+A group, and because of a change in the drug applied in one episode in the T group and two episodes in the C+A group. Overall success was 96 percent (T) and 93 percent (C+A). Adverse events that occurred in group T were not related to the drugs used in this study. CONCLUSION: In pediatric and adolescent patients with leukemia or lymphoma, who presented with fever and neutropenia, during chemotherapy, ticarcillin/clavulanic acid was as successful as the combination of ceftriaxone plus amikacin. It should be considered an appropriate option for this group of patients at high risk for infections

Sensibilidade aos antimicrobianos de amostras Pseudomonas aeruginosa e acinetobacter spp: dados do programa de vigilância RESISTNET Brasil / Antimicrobial susceptibility of pseudomonas aeruginosa e acinetobacter spp: RESISTNET Brasil surveillance program

O programa RESISTNET é um estudo de vigilância de resistência bacteriana a diversos antimicrobianos. Trata-se de um projeto latino-americano iniciado em abril de 1998. No final de 1999, este programa no Brasil passou a denominar-se RESISTNET Brasil. Um dos principais objetivos deste estudo é gerar dados pontuais, atualizados e confiáveis da atual situaçäo da resistência bacteriana a diversos antimicrobianos. Neste trabalho, apresentamos os resultados obtidos durante 12 meses (janeiro a dezembro de 1999), num total de 705 amostras bacterianas, respectivamente 524 amostras de Pseudomonas aeruginosa e 181 amostras de Acinobacter spp, isoladas de diversos materiais clínicos provenientes de pacientes da comunidade (167 amostras) e hospitalizados (538 amostras) de 13 centros em seis cidades brasileiras (Säo Paulo, Porto Alegre, Curitiba, Brasília, Salvador e Fortaleza). Os isolados foram testados pelo método da difuçäo do disco, de acordo com as normas estipuladas pelo NCCLS (11), aos seguintes antimicrobianos: aztreonam, amicacina, cefepima, ceftazidima, cefoperazona, colistina, ciprofloxacina, gentamicina, imipenem, piperacilina,ticarcilina/ácido clavulânico, amplicilina/sulbactam e tobramicina, Em relaçäo a Pseudonomas aeruginosa, os antimicrobianos mais ativos foram, respectivamente: colistina, imipenem, ceftazidima, cefepima e ciprofloxacina (taxas de sensibilidade de 100 por cento, 78,6 por cento, 77 por cento, 67,6 por cento e 66 por cento). Para Acinobacter spp, os antimicrobianos mais ativos foram: colistina, imipenem, amplicilina/sulbactram e trobamicina (taxas de sensibilidade de 100 por cento, 98,9 por cento, 82,8 por cento e 55,6 por cento respectivamente). As amostras de origem hospitalar apresentaram índices maiores de resistência quando comparadas com as amostras provenientes da comunidade. Os resultados deste levantamento mostram a importância de estudos de resistência aos microbianos, pois estes bacilos Gram negativos näo fermentadores, além de serem responsáveis por diversas infecçöes humanas, mostram significativas taxas de resistência a diversos antimicrobianos

In vitro antimicrobial activity of piperacillin/tazobactam in comparison with other broad-spectrum ß-Lactams

Combinig tazobactam, a ß-lactamase inhibitor, with the ureidopenicillin, piperacillin, successfully restores the activity of piperacillin against ß-lactamase producing bacteria. Thus, piperacillin/tazobactam is highly active against most clinically important species of Gram-negative and Gram-positive bacteria, including anaerobes. We evaluated the in vitro activity of piperacillin/tazobactam against clinical isolates from a tertiary university hospital located in Säo Paulo, Brazil. Its activity was compared to the ticarcillin/ clavulanic acid, ampicillin/sulbactam, ceftazidimeceftriaxone, cefotaxime, cefoxitin, aztreonam and imipenem against 820 isolates (608 Gram-negative and 212 Gram-positive) collected from hospitalized patients in 1999. The most frequent species tested were Pseudomonas aeruginosa (168/20 por cento), Escherichia coli (139/17 por cento), Acinetobacter spp (131/16 porcento), and Staphylococcus aureus (76/9 por cento). Of the isolates studied, 30 por cento were from the blodstream, 16 porcento from the lower respiratory tract, and 11 por cento from surgical wounds or soft tissue. The isolates were susceptibility tested by the broth microdilution method according to NCCLS procedures. The isolates tested were highly resistant to most antimicrobial agents evaluated. Imipenem resistance was not verified among Enterobacteriaceae, and piperacillin/tazobactam was the second most active ß-lactam against this group of bacteria (80.0 por cento susceptibility). Extended-spectrum ß-lactamase production was very high among E. coli (approximately 20 por cento) and KLebsiella pneumoniae (approximately 40 por cento). Imipenem was uniformly active against these species (100 por cento susceptibility) and piperacillin/tazobactam was the second most active compound inhibiting 84.4 por cento of isolates. Pseudomonas aeruginosa was highly resistant to all ß-lactams evaluated and piperacillin/tazobactam was the most active compound against this species. Our results demonstrate an extremely high level of antimicrobial resistance in the hospital evaluated, especially among non-enteric Gram-negative bacilli. Due to this high level of resistence, piperacillin/tazobactam represents an important ciontribution to the treatment of nosocomial infections...

Susceptibility of clinical isolates of Bacteroides fragilis group strains to cefoxitin, cefoperazone and ticarcillin/clavulanate

A total of 40 strains of the B. fragilis group was isolated from clinical specimens in two hospital centers in Fortaleza from 1993 to 1997. The most frequently isolated species was Bacteroides fragilis (19 strains) and most isolates came from intra-abdominal and wound infections. The susceptibility profile was traced for cefoxitin, cefoperazone and ticarcillin-clavulanate by using the agar dilution reference method. All isolates were susceptible to ticarcillin-clavulanate (128/2mug/ml). Resistance rates of 15 and 70 percent were detected to cefoxitin (64mug/ml) and cefoperazone (64mug/ml), respectively. Such regional results permit a better orientation in choosing this group of antibiotics for prophylaxis and therapy especially in relation to cefoxitin, which is frequently used in the hospital centers studied.

Comparative evaluation of the in vitro activity of three combinations of ß-Lactamase inhibitors: piperacillin/tazobactam, ticarcillin/clavulanic acid and amplicillin/sulbactam

Recently, two new combinations of ß-lactam antibiotics with ß-lactamase inhibitors become commercially avaiable in Brazil: piperacillin/tazobactam and ampicillin/sulbactam. This study was designed to assess and compare the in-vitro activity of theses new compounds, as well as that of ticarcillin/clavulanic acid, against bacteria isolated in our environment. A total of 749 bacteria isolated at São Paulo Hospital were tested using the disk diffusion method, in compliance with NCCLS Standardization, using strict quality control. Only one sample per patient was included in the study. Oxacillin-resistant staphylococcus samples were not included in this study. Of the total samples tested 84.5 percent were susceptible to piperacillin/tazobactam, 81.2 percent to ticarcillin/clavulanic acid, and 77.6 percent to ampicillin/sulbactam. Piperacillin/tazobactam was also found to be the most active combination of the three against Enterobacteriaceae (n=312), inhibiting 91.7 percent of the bacteria tested. Ticarcillin/clavulanic acid was active against 85.8 percent of the Enterobacteriaceae, while ampicillin/sulbactam inhibited 83.2 percent of the samples...

Isolates of Bacteria and Their Sensitivity to Antibiotics in Fungal Maxillary Sinusitis / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: In patients with fungal sinusitis, purulent discharge from the maxillary sinus is frequently observed and it responds to antibiotic treatment. Even though fungal sinusitis is resolved after surgery, the purulent discharge continues in some cases. We aimed to identify the pathogens of the purulent discharge in fungal sinusitis and to obtain information for appropriate antibiotics through a sensitivity test. MATERIALS AND METHOD: Among 71 patients with fungal sinusitis of the maxillary sinus, purulent secretions were found in 44 patients (62%) during an endoscopic sinus surgery. Endoscope-guided collection of the maxillary sinus secretions were performed and specimens were sent to the laboratory for bacterial cultures and antibiotic sensitivity tests. RESULTS: Among 44 cases with fungal lesions and purulent secretion in the maxillary sinus, bacteria were isolated in 27 cases (61.4%). Gram (+) aerobes were recovered in 19 cases, and Gram (-) aerobes were recovered in 16 cases. Mixed infection by Gram (+) and Gram (-) bacteria were observed in 8 patients. Anaerobic bacteria were not isolated. Among the Gram (+) aerobes, S. aureus was the most common organism (8 cases), while Enterobacter aerogenes was the most common organism (7 cases) of the Gram (-) aerobes. In an antibiotic sensitivity test for Gram (+) bacteria, ciprofloxacin, vancomycin, and teicoplanin showed sensitivity over 85 %. For Gram (-) bacteria, ceftazidime, ciprofloxacin, ticarcillin, tobramycin, and imipenem showed sensitivity over 90%. CONCLUSION: In patients with fungal sinusitis, concomitant bacterial infections are identified in more than half of the cases. Thus, postoperative administration of appropriate antibiotics can be justified in the treatment of fungal sinusitis.

A Case of Sepsis by Bifidobacterium longum / 대한임상병리학회지

Bifidobacterium longum, indigenous bacteria of the gastrointestinal tract, is a species of anaerobic non-spore-forming gram-positive bacilli, and appears to play an important role in preventing overgrowth of pathogenic bacteria. This organism is very rarely isolated from clinical specimens. It is known to be very difficult to identify Bifidobacterium longum due to not only the variability in aerotolerance, colony morphology and stainability on gram staining, resulting the failure of distinguishing from other anaerobic non-spore-forming gram-positive bacilli by the conventional biochemical tests. Definitive identification of genus Bifidobacterium requires the analysis of the end-products of metabolism, volatile and non-volatile fatty acids, by gas-liquid chromatography (GLC). We report a case of sepsis caused by Bifidobacterium longum in a 19-year-old male who developed high fever, jaundice and hepatomegaly after he had been introduced with many small gold needles. Anaerobic non-spore-forming gram-positive bacilli were isolated from his blood and identified as Bifidobacterium longum by performing biochemical tests and the analysis of the metabolic end-products by GLC. He has been completely recovered after ticarcillin and metronidazole therapy. To our knowledge, this is the first report of incidental sepsis by Bifidobacterium longum in the world.

La neumonía atípica por Legionella pneumophila: informe del segundo caso en México / Atypical pneumonia caused by Legionella pneumophila: second case report in Mexico

En 1977 se informó de 34 muertes por neumonía en 221 asistentes a la Convención de la Legión Americana en Filadelfia. El agente causal fue identificado y llamado Legionella pneumophila. La legionellosis es una enfermedad de distribución mundial, pero en México sólo hay un caso informado, posiblemente por no considerarse en el diagnóstico diferencial de las neumonías adquiridas en la comunidad. Informamos el caso de una paciente previamente sana en la que se diagnosticó una neumonía secundaria a Legionella pneumophila