Abstract The purpose of this study was to identify the risk factors that predispose patients who are hospitalized with pressure ulcers (PUs) colonized by Gram-negative bacilli (GNB) to develop bacteremia. In addition, we also detected main phenotypes of resistance in infected and uninfected PUs. A prospective cohort study was conducted at the Clinical Hospital of the Federal University of Uberlândia including patients with Stage II or greater PUs, colonized or not with GNB, from August 2009 to July 2010. Infected ulcers were defined based on clinical signs and on positive evaluation of smears of wound material translated by a ratio of polymorphonuclear cells to epithelial cells ≥2:1, after Giemsa staining. A total of 60 patients with Stage II PUs were included. Of these 83.3% had PUs colonized and/or infected. The frequency of polymicrobial colonization was 74%. Enterobacteriaceae and GNB non-fermenting bacteria were the most frequent isolates of PUs with 44.0% of multiresistant isolates. Among patients who had infected PUs, six developed bacteremia by the same microorganism with a 100% mortality rate. In addition, PUs in hospitalized patients were major reservoir of multiresistant GNB, also a high-risk population for the development of bacteremia with high mortality rates.

Background:In Brazil, ventilator-associated pneumonia (VAP) caused by carbapenem resis- tant Acinetobacter baumanniiand Pseudomonas aeruginosaisolates are associated with significant mortality, morbidity and costs. Studies on the clonal relatedness of these isolates could lay the foundation for effective infection prevention and control programs.Objectives: We sought to study the epidemiological and molecular characteristics of A. baumannii vs. P. aeruginosaVAP in an adult intensive care unit (ICU).Methods: It was conducted a cohort study of patients with VAP caused by carbapenem resistant A. baumanniiand P'. aeruginosaduring 14 months in an adult ICU. Genomic studies were used to investigate the clonal relatedness of carbapenem resistant OXA-23-producing A. baumanniiand P. aeruginosaclinical isolates. The risk factors for acquisition of VAP were also evaluated. Clinical isolates were collected for analysis as were samples from the environment and were typed using pulsed field gel electrophoresis.Results: Multivariate logistic regression analysis identified trauma diagnosed at admission and inappropriate antimicrobial therapy as independent variables associated with the development of A. baumanniiVAP and hemodialysis as independent variable associated with P. aeruginosaVAP. All carbapenem resistant clinical and environmental isolates of A. baumanniiwere OXA-23 producers. No MBL-producer P. aeruginosawas detected. Molecular typing revealed a polyclonal pattern; however, clone A (clinical) and H (surface) were the most frequent among isolates of A. baumanniitested, with a greater pattern of resistance than other isolates. In P. aeruginosathe most frequent clone I was multi-sensitive.Conclusion: These findings suggest the requirement of constant monitoring of these microor- ganisms in order to control the spread of these clones in the hospital environment.

OBJECTIVE: To investigate the pathogenesis of bloodstream infection by Staphylococcus epidermidis, using the molecular epidemiology, in high-risk neonates. METHODS: We conducted a prospective study of a cohort of neonates with bloodstream infection using central venous catheters for more than 24 h. "National Healthcare Safety Network" surveillance was conducted. Genotyping was performed by DNA fingerprinting and mecA genes and icaAD were detected by multiplex-PCR. RESULTS: From April 2006 to April 2008, the incidence of bloodstream infection and central venous catheter-associated bloodstream infection was 15.1 and 13.0/1000 catheter days, respectively, with S. epidermidis accounting for 42.9% of episodes. Molecular analysis was used to document the similarity among six isolates of bloodstream infection by S. epidermidis from cases with positive blood and central venous catheter tip cultures. Fifty percent of neonates had bloodstream infection not identified as definite or probable central venous catheter-related bloodstream infection. Only one case was considered as definite central venous catheter-related bloodstream infection and was extraluminally acquired; the remaining were considered probable central venous catheter-related bloodstream infections, with one probable extraluminally and another probable intraluminally acquired bloodstream infection. Additionally, among mecA+ and icaAD+ samples, one clone (A) was predominant (80%). A polyclonal profile was found among sensitive samples that were not carriers of the icaAD gene. CONCLUSIONS: The majority of infections caused by S. epidermidis in neonates had an unknown origin, although 33.3% appeared to have been acquired intraluminally and extraluminally. We observed a polyclonal profile between sensitive samples and a prevalent clone (A) between resistant samples.

Estudou-se a construção de sistemas de LED aplicados a processos de fotosensitização. Visando à obtenção de dispositivos mais eficientes avaliou-se a aplicação de LED de alta potência (HPLED), que apresenta maior fluxo fotônico, tendendo a excitar uma maior fração de moléculas. Foram descritos detalhes de construção de 3 diferentes sistemas de irradiação completamente distintos (lâmpada halógena filtrada, LED convencional, HPLED), utilizando azul de metileno como fotosensitizador. A comparação entre a eficiência de cada equipamento foi realizada através da cinética de fotooxidação de 1,3-Diphenylisobenzofuran e inativação de Staphylococcus aureus. A emissão de luz de cada equipamento, sobreposta à absorção do fotosensitizador, também se mostrou um importante parâmetro na estimativa da eficiência dos equipamentos. Foi observada uma inibição bacteriana superior a 99% para concentrações de 5 × 10-6 mol dm-3 de fotosensitizador, no sistema que emprega HPLED. Os equipamentos baseados em LED, apresentaram resultados satisfatórios além de baixo custo e simples montagem.

The construction of LED systems applied to photosensitization processes was studied. Aiming to obtain more efficient devices it was evaluated the use of high intensity LED (HPLED), that present greater photonic flux, tending to excite a greater fraction of molecules. Construction details for 3 different irradiation systems were described (filtered halogen bulbs, conventional LED, HPLED), using methylene blue as a photosensitizer. A comparison between the efficiency of the equipments was carried out through the kinetics of photooxidation of 1,3-Diphenylisobenzofuran and Staphylococcus aureus photoinactivation. The overlap between the light emited from each equipment and the photosensitizer absorption, was also an important parameter in estimating the efficiency of the equipment. Bacterial inhibition higher than 99% for concentrations of 5 × 10-6 mol dm-3 of the photosensitizer was observed, in the system that uses HPLED. The equipments based on LED showed satisfactory results, besides their low cost and simple to assembling.

Staphylococcus aureus and coagulase-negative staphylococci are the main cause of sepsis in Neonatal Intensive Care Unit (NICU). Central venous catheters (CVCs) are an important part of critical neonates' treatment and are associated with sepsis. The aim of this study was to investigate two outbreaks caused by Staphylococcus aureus and Staphylococcus epidermidis associated with CVC inserted by phlebotomy in critical neonates. The surveillance was performed from January 2001 to December 2005 at the Brazilian NICU. The genotypic analysis of oxacillin susceptible S. aureus (OSSA) and oxacillin resistant S. epidermidis (ORSE) was performed based on pulsed-field gel electrophoresis (PFGE). Staphylococcus was the most frequent pathogen (65.8%) with highest incidence of CoNS (59.9%) followed by S. aureus (40.1%). During the five years of surveillance, there were two outbreaks detected, occurred in January-February/02 and August/02 and confirmed by PFGE analysis. The predisposing factors for infection corresponding to both outbreaks were: age <7 days, hospitalization > 7 days, and use of polyethylene CVC through dissection of vein (phlebotomy). This is the first relate of staphylococcal outbreaks associated with CVC inserted by phlebotomy in NICU. PFGE showed polyclonal spread of OSSA during both epidemic and endemic period, and two monoclonal outbreaks of ORSE in the same epidemic period of OSSA.

This study investigated the participation and risk factors of VAP by resistant (ORSA) or sensitive (OSSA) S. aureus to oxacillin and evaluated the implications of adequate or inadequate empirical antimicrobial therapeutics in its evolution in patients interned in a mixing ICU of adults. A patient control-case study with PAVs by ORSA and OSSA was carried out from May 2005 to April 2007 involving 993 patients. VAP was defined based on clinical, radiological, and microbiological (> 106 CFU/mL count in the tracheal aspirate) criteria. Four hundred and seventy four (47.7%) patients were submitted to mechanical ventilation with 141 (29.7%) VAPs, with S. aureus as the most frequent agent (41.2%). The phenotype ORSA accounted for 47.5% and OSSA for 52.5%, predominant in late-onset VAPs with frequencies of 93.1% and 68.7%, respectively. Age > 60, use of corticoid and previous antibiotic therapy were related (p<0.05) with the development of VAP by ORSA. Mortality rate was higher (p>0.05) in the group with VAP by ORSA (37.9%). S. aureus was the main agent of VAPs, around half by ORSA, associated with age, late-onset VAP development and previous use of antibiotics and corticoids, but with no significant difference in mortality compared with VAP by OSSA.

A resistência aos antimicrobianos é uma ameaça a saúde pública mundial e está associada a uma maior mortalidade e morbidade. Apesar dos vastos conhecimentos sobre este problema, a resistência aos antibióticos continua a emergir, especialmente em unidades de terapia intensiva (UTI). O objetivo deste estudo foi avaliar a freqüência de fenótipos de resistência epidemiologicamente importantes em patógenos isolados de pneumonia associada à ventilação mecânica (PAV), infecções de corrente sangüínea (ICS) e de infecções de trato urinário (UTI) nos pacientes atendidos na unidade de terapia intensiva de adultos (UTIA) do Hospital de Clínicas da Universidade Federal de Uberlândia, durante o período de um ano. Adicionalmente, no período do estudo, foi analisado o consumo de antibióticos na UTIA. Staphylococcus spp coagulase negativo e S. aureus foram os principais agentes de ICS (43,9%), com 60,0% de resistência à oxacilina em ambos os microrganismos. O grupo Klebsiella-Enterobacter predominou nas ITU (23,4%), com resistência às cefalosporinas de terceira geração em 58,0% dos isolados; e, Pseudomonas aeruginosa nas PAV (42,0%), com 72,0% de resistência ao imipenem. As cefalosporinas (49,6%), vancomicina (37,4%) e os carbapenêmicos (26,6%) foram os antibióticos mais prescritos na unidade. A comparação dos resultados com publicações do programa NNIS evidenciou uma pior situação no hospital estudado, especialmente entre os Gram-negativos, que ultrapassaram o percentil 90% elaborado por este programa. De acordo com os resultados apresentados neste estudo, uma revisão do uso empírico de antibióticos e da prevenção e controle de infecções hospitalares é recomendada.

Antimicrobial resistance is a threat to public health worldwide and is associated with higher mortality and morbidity. Despite the extensive knowledge about this problem, drug resistance has continued to emerge, especially in intensive care units (ICUs). The objective of this study was to evaluate the frequencies of epidemiologically relevant resistance phenotypes in pathogens isolated from ventilator-associated pneumonia (VAP), bloodstream infections (BSI) and urinary tract infections (UTI) in patients admitted in the adult intensive care unit (AICU) of the Clinical Hospital of Federal University of Uberlândia, during an one year period. Additionally, at the period of the study, the antibiotic consumption in AICU was verified. Coagulase-negative staphylococci and S. aureus were the main agents of BSI (43.9%), with 60.0% of oxacilin-resistance for both microorganisms, Klebsiella-Enterobacter group predominated in UTI (23.4%), with resistance to third generation cephalosporins in 58.0% of the isolates; and, Pseudomonas aeruginosa in VAP (42.0%), with 72.0% of resistance to imipenem. Cephalosporins (49.6%), vancomycin (37.4%) and carbapenems (26.6%) were the most prescribed antibiotics in the unit. The comparison of the results with a publication of the NNIS program evidenced a worse situation in the studied hospital, mainly between Gram-negative, that had surpassed the percentile 90% elaborated by that system. Based on these results a reconsideration on the empirical use of antibiotics and on prevention and control of nosocomial infections practices is recommended.

The objective of this study was to evaluate clinical characteristics, etiology, and resistance to antimicrobial agents, among patients with ventilator-associated pneumonia (VAP). A case study vs. patients control under mechanical ventilation and hospitalized into clinical-surgical adults ICU of HC-UFU was performed from March/2005 to March/2006. Patients under ventilation for over 48 h were included in the study including 84 with diagnosis of VAP, and 191 without VAP (control group). Laboratory diagnosis was carried out through quantitative microbiological evaluation of tracheal aspirate. The identification of pathogens was performed by classical microbiological tests, and the antibiotics sensitivity spectrum was determined through the CLSI technique. VAP incidence rate over 1,000 days of ventilation was 24.59. The mean (± SD) duration of mechanical ventilation prior to VAP diagnosis was 23.2 ± 17.2 days. By multivariate analysis the risk factors predisposing for VAP were: mechanical ventilation time and mechanical ventilation > seven days, tracheostomy and use of > three antibiotics. Mortality rate was high (32.1 %) but lower than that of the control group (46.5%). Major pathogens were identified in most of patients (95.2%) and included: Pseudomonas aeruginosa (29%), Staphylococcus aureus (26%), Enterobacter/Klebsiella/Serratia (19%) and Acinetobacter spp. (18%), with expressive frequencies of P. aeruginosa (52%), S. aureus (65.4%) and Enterobacteriaceae (43.7%) resistant to imipenem, oxacillin and 3/4 generation cephalosporins, respectively. In conclusion, our observation showed VAPs caused by multiresistant microorganisms, the prescription of > three antibiotics, and mortality with unacceptably high rates. The practice of de-escalation therapy appears to be urgently needed in order to improve the situation.

We report the first case of vancomycin-resistant Enterococcus faecalis with VanA phenotype and vanA genotype isolated from a surgical patient in a general Hospital in Uberlândia, state of Minas Gerais, Brazil.

Bacteremia is one of the most frequent and challenging hospital-acquired infection and it is associated with high attributable morbidity and mortality and additional use of healthcare resources. The objective of this work was to determine the frequencies of its occurrence, organisms and resistance phenotypes associated to nosocomial acquired bloodstream infections. A total number of 51 nosocomial bacteremia by Gram-negative and 99 by Gram-positive were evaluated and compared during a 15-month period. The risk factors associated with these bacteremias were analyzed and antibiotic use and surgery were associated with bacteremia by Gram-negative and > 2 invasive devices with Gram-positive. The resistance phenotypes ESBL (extended-spectrum beta-lactamases) (23.5%) and AmpC/others (17.6%) correspond to 41.2 % with predominance of E. agglomerans among AmpC (44.4%) and K. pneumoniae among ESBLs (38.5%). Among S. aureus bacteremia, approximately 40% were associated to MRSA (methicillin-resistant Staphylococcus aureus).

CVC is the main factor of risk of bloodstream infections. This study purpose was determining both etiology and pathogenesis of these infections in 80 patients who undergone gastrointestinal surgery and who worn long lasting CVC, in the institution HC-UFU. Cultures were made in nostril, skin of the insertion site, tip and catheter hub, in addition to hemoculture in those suspects of sepsis. The colonization incidence rate of the catheter tip was 12.5/ 1,000 catheter days and the CVC associate infection rate was 3.1/1,000 catheter days. Frequencies of skin, hub and catheter tip colonization were 13.8%, 8.9% and 13.3%, respectively. Coagulase-negative Staphylococci were the most found microorganisms in nostril (74%), skin (45.4%) and hub (75%) and Gram-negative bacilli (50%), followed by S. aureus (25%) the most common ones in catheter tip. Approximately 51% of patients received antibiotics and most of them (53.7%) had therapeutic purpose. The frequency of patients with clinical sepsis was 27.5%. Three cases of bacteremia associated with the use of CVC were detected (3.8%), with S. aureus in two of them and K. pneumoniae in the third one. There was not seen any association of skin and hub colonization with their presence in the catheter tip and in the blood of these patients, but S. aureus was recovered from nostril of those with sepsis by this pathogenic agent. A greater concern is suggested over preventive measures and control of these primary and secondary bloodstream, as well as catheter tip colonization.

Staphylococcus aureus e Estafilococos coagulase-negativa (ECN) estão entre os patógenos hospitalares mais importantes em pacientes de unidades de terapia intensiva neonatal, principalmente em infecções da corrente sanguínea. O principal objetivo deste estudo foi determinar a ocorrência de infecções hospitalares por estes microrganismos usando dois sistemas de vigilância (laboratorial e "National Nosocomial Infection Surveillance" - NNIS) e determinar os fatores de risco mais importantes durante o período de dois anos (2001-2002). Dois surtos por ambos S. aureus suscetível a meticilina (1.5%) e ECN resistente à meticilina (1.0%) foram observados, de janeiro a fevereiro/02 e agosto a setembro/02. Taxas de incidência endêmica de 3.77% e 5.16% para S.aureus e ECN foram detectadas respectivamente. Fatores de risco incluíram idade <=7 dias, hospitalização > ou = 7 dias e utilização de cateter vascular central (CVC) de polietileno através de dissecação de veia (flebotomia), mas, nenhum desses fatores independentes foram confirmados pela análise multivariada. Por outro lado, ECN resistente à oxacilina prevaleceu (66.0%) nos episódios epidêmicos. Análise molecular através de gel de eletroforese em campo pulsátil mostrou a natureza policlonal das amostras de S. aureus. Em conclusão, nós identificamos dois surtos de etiologia mista por S. aureus suscetível à meticilina e ECN resistente à meticilina associados à falta de material adequado (cateter vascular central) para neonatos, relacionados a procedimento invasivo. Os dois surtos foram controlados com a substituição de CVC de polietileno pelo cateter central de inserção periférica.

Staphylococcus aureus and coagulase-negative staphylococci (CoNS) are among the most important nosocomial pathogens in patients from neonatal intensive care units, mainly in bloodstream infections. The main objective of this study is to determine the occurrence of nosocomial infections by these microorganisms using two surveillance systems (Laboratorial Surveillance and National Nosocomial Infection Surveillance System) and to determine the most important risk factors during a two-year period (2001-2002). Two outbreaks by both methicillin susceptible S. aureus (MSSA) (1.5%) and methicillin resistant CoNS (MRCoNS) (1.0%) were observed, from January to February/02 and August to September/02. Endemic incidence rates of 3.77% and 5.16% of S. aureus and CoNS, respectively were detected. Risk factors included age <=7 days, hospitalization > or = 7 days and utilization of polietilene central vascular catheter (CVC) through vein dissection (phlebotomy), but none of these independent factors were confirmed by the multivariate analysis. However, oxacillin resistant CoNS prevailed (66.0%) in the epidemic episodes. Molecular analysis by pulsed field gel electrophoresis showed the polyclonal nature of S. aureus isolates. In conclusion, two outbreaks were identified of mixed etiology by MSSA and MRCoNS associated to the lack of an adequate material (central venous catheter) for neonates, related invasive procedure. The outbreaks were controlled with the substitution of polietilene CVC for peripherally inserted central catheter.

We studied an outbreak of two multi-drug resistant clones of Acinetobacter baumannii in the Neonatal Intensive Care Unit of the Uberlândia Federal University Hospital in Minas Gerais state, Brazil, and we analyzed the contribution of cross-transmission in the rise in infection rates. Eleven neonates who developed multi-drug resistant A. baumannii nosocomial infection were matched to 22 neonates who were admitted to the same unit and did not develop an infection during the outbreak period, in order to identify risk factors for infection. Three out of the 11 neonates died. Epidemiological investigation included molecular typing, using pulsed field gel electrophoresis. Prior to the outbreak, from December 2001 to March 2002, no case of infection by this microorganism was diagnosed. Environmental and healthcare worker hand cultures were negative. Nine isolates had similar pulsed field gel electrophoresis patterns and two had another clone. The first clone was brought into the unit by an infected patient who was transferred from another hospital without a history of antibiotic use. The second clone did have its origin clearly defined. Both infected groups led us to conclude that several factors contributed to infection with A. baumannii. These factors were: exposure to antibiotics and invasive devices, birth weight < 1500g, age < 7 days and duration of hospitalization > 7 days. Based on logistic regression, infected neonates were more exposed to carbapenem and mechanical ventilation than the control group. Cross transmission between infants contributed to the rise in the rates of multi-drug resistant A. baumannii infection.

Staphylococcus aureus resistente à meticilina (MRSA) e Staphylococcus coagulase negativo resistente à meticilina (MRCoNS) são os agentes mais freqüentes em infecções hospitalares mundialmente, justificando o incremento no uso de vancomicina. Neste estudo avaliamos a presença de Staphylococcus resistentes aos glicopeptideos em 41 pacientes, em uso de vancomicina, hospitalizados no Hospital de Clínicas da Universidade Federal de Uberlândia em Uberlândia-MG. Todos os isolados foram semeados em agar Mueller-Hinton acrescido do antimicrobiano. A resistência a vancomicina foi confirmada por crescimento após incubação por 24-48 horas a 35ºC. A heterorresistência foi avaliada por semeadura com inóculo mais denso (10(8) UFC/mL). Um paciente com nefrite, no programa de hemodiálise teve o fenótipo de Staphylococcus aureus com resistência intermediária à vancomicina (VISA) (CIM= 8 mig/mL) e em oito pacientes as amostras apresentaram heterorresistência (hVISA). Além do uso prévio de vancomicina outros fatores de risco incluindo três ou mais antimicrobianos, cirurgia e três ou mais procedimentos invasivos, foram observados. A análise molecular foi realizada por amplificação randômica de DNA polimórfico em reação em cadeia da polimerase (RAPD-PCR) mostrando dois clusters com duas amostras cada um, em pacientes cirúrgicos, com relação temporal espacial e com perfil de susceptibilidade semelhantes quando frente à vários outros antimicrobianos.

Methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant coagulase-negative staphylococci (MRCoNS) are among the most frequent causes of hospital infections worldwide, thus justifying the increasing use of vancomycin. In this study, we evaluated the presence of glycopeptide-resistant staphylococci, in 41 patients hospitalized in the Clinical Hospital of the Federal University of Uberlândia in Uberlândia, MG, who were being treated with vancomycin. All isolates were plated on Mueller-Hinton agar containing vancomycin. Vancomycin resistance was confirmed by surface growth after incubation for 24-48 h at 35ºC. Heteroresistance was evaluated by plating with a large inoculum (10(8) CFU/mL). One patient with nephritis who was on a hemodialysis program was diagnosed with the phenotype isolate of vancomycin-intermediate Staphylococcus aureus (VISA) (CIM = 8 mug/mL) and in eight patients, strains of heteroresistant Staphylococcus corresponding to the hVISA phenotype were isolated. In addition to the extended use of vancomycin, other risk factors associated with the presence of these microorganisms included the use of three or more antimicrobial agents, surgery, and three or more invasive procedures. Molecular analysis by randon amplified polymorphic DNA polymerase chain reaction (RAPD-PCR) showed two clusters involving two samples each one of them, in surgical patients, with temporal and spatial relationship and isolates similarity concerning the susceptibility range to antimicrobial agents.

Os objetivos deste estudo foram determinar infecções endêmicas e epidêmicas por bacilos Gram-negativos, fatores de risco associados a colonização e infecção e a presença dos fenótipos de resistência ESBL e AmpC em neonatos admitidos em Berçário de Alto Risco. Durante um período de 21 meses, foi realizado um estudo prospectivo para avaliar os casos de infecções hospitalares e o uso de cefalosporinas de terceira geração; e um estudo caso-controle para determinar os fatores de risco associados a colonização/infecção. Quatro inquéritos de colonização da orofaringe e intestino dos neonatos (Setembro e Novembro/2001, Fevereiro e Agosto/2002). Amostras com resistência a 2 mig/mL de ceftazidima foram isoladas devido a suspeita de produção de b-lactamases (ESBL/ AmpC). A incidência de pacientes infectados por bacilos Gram-negativos foi de 2,4% (89/3.709 neonatos), sendo sepse (35,9%) e conjuntivite (31,4%) as síndromes mais frequentes. A maioria das infecções foram endêmicas (73,9%) e associadas a Enterobacteriaceae (95,5%), estes também foram relacionados à colonização, correspondendo principalmente as amostras de Enterobacter spp e Klebsiella spp.. Foram identificados dois surtos, durante o estudo, associados a Pseudomonas aeruginosa (N=10) e Acinetobacter baumannii (N=11). Os fatores de risco incluindo: tempo de internação, uso de antimicrobianos, ventilação mecânica, cateter vascular central, cirurgia e nutrição parenteral foram significativos em uma análise univariada e considerados um risco para infecção por bacilos Gram-negativos. A maioria das amostras de Enterobacteriaceae (80,9%) com resistência a 2 mig/mL de ceftazidima foram do fenótipo ESBL. O uso de cefalosporinas de terceira geração (ceftriaxona) na unidade neonatal favoreceu a emergência de bacilos Gram-negativos multiresistentes.

The aims of this study were to determine endemic and epidemic infection due to Gram-negative bacilli, risk factors associated with colonization and infection by these organisms and the resistance phenotypes (ESBL, AmpC) in neonates admitted in a High Risk Nursery. The study was conducted during a 21 month period and included: a prospective study to evaluate the neonates with hospital infection and the use of third-generation cephalosporins; a case-control study to determine the risk factors associated with colonization/infection. Rectal and oropharynx cultures were also performed in four opportunities (September and November 2001, February and August 2002). The isolates for which the resistance of ceftazidime was 2 mg/mL were suspected of producing ESBL or AmpC b-lactamases. The incidence of infection by Gram-negative bacilli was 2.4% (89/3.708 neonates), and sepsis (35.9%) and conjunctivitis (31.4%) were the most common infections. The endemic infections were more prevalent (73.9%) and usually associated with Enterobacteriaceae (95.5%), being these organisms also related to colonization, corresponding mainly to isolates of Enterobacter spp. and Klebsiella spp. Two outbreaks of Pseudomonas aeruginosa (n=10) and Acinetobacter baumannii (n=11) were identified during the survey. Univariate analysis showed that risk factors for Gram-negative bacilli infection considered significant included: the length of stay before infection/colonization, exposure to antimicrobial agents, mechanical ventilation, central venous catheters, parenteral nutrition and surgery. The majority of resistance to ceftazidime among Enterobacteriaceae isolates (80.9%) was from ESBL phenotype. Administration of third-generation cephalosporins (ceftriaxone) led to the emergence of these multiresistant Gram-negative bacilli in the neonatal unit.