Keiji Kanemitsu

Outbreak of extended-spectrum β-lactamase-producing Escherichia coli transmitted through breast milk sharing in a neonatal intensive care unit

BACKGROUND Routine surveillance in a neonatal intensive care unit (NICU) showed an increased detection of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli (ESBL-E. coli) in August 2012, following nearly a year without detection. AIM To describe the investigation and interventions by a hospital infection control team of an outbreak of ESBL-E. coli in a NICU. METHODS Six neonates with positive cultures of ESBL-E. coli (five with respiratory colonization, one with a urinary tract infection), control infants who were negative for ESBL-E. coli during the study period, and mothers who donated their breast milk were included. A case-control study was performed to identify possible risk factors for positive ESBL-E. coli cultures and molecular typing of isolated strains by pulsed-field gel electrophoresis. FINDINGS The odds ratio for ESBL-E. coli infection after receiving shared unpasteurized breast milk during the study period was 49.17 (95% confidence interval: 6.02-354.68; P < 0.05). The pulsed-field gel electrophoresis pattern showed that all strains were identical, and the same pathogen was detected in freshly expressed milk of a particular donor. After ceasing the breast milk sharing, the outbreak was successfully terminated. CONCLUSION This outbreak indicates that contamination of milk packs can result in transmission of a drug-resistant pathogen to newborn infants. Providers of human breast milk need to be aware of the necessity for low-temperature pasteurization and bacterial cultures, which should be conducted before and after freezing, before prescribing to infants.

Efficacy of 1.0% chlorhexidine-gluconate ethanol compared with 10% povidone-iodine for long-term central venous catheter care in hematology departments: a prospective study.

The efficacy of 1% chlorhexidine-gluconate ethanol and 10% povidone-iodine for skin antisepsis of central venous catheter (CVC) sites were compared among hematology patients. The CVC site colonization rates of those groups were 11.9% and 29.2%, respectively, and the catheter-associated blood stream infections were 0.75 and 3.62 per 1,000 catheter-days, respectively. One percent chlorhexidine-gluconate ethanol was superior to povidone-iodine to reduce skin colonizers at CVC sites even when catheters were used for long duration.

Expression of activation-induced cytidine deaminase enhances the clearance of pneumococcal pneumonia: evidence of a subpopulation of protective anti-pneumococcal B1a cells.

We describe a protective early acquired immune response to pneumococcal pneumonia that is mediated by a subset of B1a cells. Mice deficient in B1 cells (xid), or activation‐induced cytidine deaminase (AID−/−), or invariant natural killer T (iNKT) cells (Jα18−/−), or interleukin‐13 (IL‐13−/−) had impaired early clearance of pneumococci in the lung, compared with wild‐type mice. In contrast, AID−/− mice adoptively transferred with AID+/+ B1a cells, significantly cleared bacteria from the lungs as early as 3 days post infection. We show that this early bacterial clearance corresponds to an allergic contact sensitivity‐like cutaneous response, probably due to a subpopulation of initiating B1a cells. In the pneumonia model, these B1a cells were found to secrete higher affinity antigen‐specific IgM. In addition, as in contact sensitivity, iNKT cells were required for the anti‐pneumococcal B1a cell initiating response, probably through early production of IL‐13, given that IL‐13−/− mice also failed to clear infection. Our study is the first to demonstrate the importance of AID in generating an appropriate B1a cell response to pathogenic bacteria. Given the antibody affinity and pneumonia resistance data, natural IgM produced by conventional B1a cells are not responsible for pneumonia clearance compared with the AID‐dependent subset.

Neonatal meningitis and recurrent bacteremia with group B Streptococcus transmitted by own mother’s milk: A case report and review of previous cases

This article reports a case of neonatal meningitis and recurrent bacteremia caused by group B Streptococcus (GBS) transmitted via the mothers milk. A 3-day-old neonate suffered early-onset meningitis due to GBS, from which he recovered after antibiotic treatment for 4 weeks. GBS was not detected in the vaginal or stool cultures of the neonates mother before delivery. However, 4days after treatment of GBS meningitis, the neonate developed GBS bacteremia. As the mother repeatedly showed signs of mastitis after the delivery, bacterial culture tests were performed on her breast milk, in addition to vaginal and stool culture tests. GBS was exclusively detected in the mothers breast milk. The GBS strains detected in the cerebrospinal fluid of the neonate and the mothers breast milk were both serotype III, and were confirmed to be identical through pulsed-field gel electrophoresis analysis. As horizontal GBS transmission between the mother and neonate was indicated, breastfeeding was ceased and replaced with formula milk. No recurrence of bacterial meningitis or bacteremia due to GBS was observed thereafter. Physicians need to consider culturing breast milk in cases of recurrent neonatal GBS infections, even in mothers without prior detection of GBS in conventional vaginal or stool cultures before delivery.

A case of typhoidal tularemia in a male Japanese farmer

In Japan, most tularemia cases occur after contact with hares (hunting, cooking) and involve the glandular or ulceroglandular form. Here, we present a case of typhoidal tularemia in a 72-year-old Japanese male farmer who presented with fever, fatigue, and right lower abdominal pain. Computed tomography revealed intestinal wall thickening at the ascending colon, pleural effusion, and ascites. Following an initial diagnosis of bacterial enteric infection, his symptoms deteriorated after a week-long cephalosporin treatment course. The patient lived in an area endemic for scrub typhus; the antibiotic was changed to a tetracycline on suspicion of scrub typhus infection. His symptoms rapidly improved after initiation of minocycline treatment. Later, blood tests revealed marked increases in serological tests against Francisella tularensis exclusively, and the patient was diagnosed with typhoidal tularemia. Typhoidal tularemia may be characterized by any combination of general symptoms, but does not exhibit the local manifestations associated with other forms of tularemia. The patient, in this case, had no direct contact with hares or other wild animals and did not present with local manifestations of tularemia. Physicians should consider this disease, especially when tick-borne disease is suspected in the absence of local wounds, eschar, ulcers, or lymphadenopathy.

Pertussis outbreak among patients and healthcare workers in a provincial dialysis facility in Japan

BACKGROUND Sixteen pertussis cases in haemodialysis patients and healthcare workers were detected in a 25-bed outpatient haemodialysis facility in Japan between October 2013 and April 2014. AIM To describe an outbreak of pertussis among patients and healthcare workers, and to identify risk factors for pertussis infection. METHODS Sputum cultures, loop-mediated isothermal amplification assays performed on nasopharyngeal swabs to detect respiratory pathogens including Bordetella pertussis, and serum anti-pertussis toxin immunoglobulin G measurements were performed for all haemodialysis patients and healthcare workers. A retrospective case-control study was performed to identify the risk factors for pertussis infection in the clinic. FINDINGS Only six of the 16 pertussis patients (37.5%) had respiratory symptoms. Recent exposure to an unmasked individual with a cough was associated with pertussis infection (odds ratio 6.25, P<0.05). The outbreak was terminated successfully after enforcing the use of surgical masks among both patients and healthcare workers. CONCLUSION This report demonstrates the risk of pertussis transmission in a haemodialysis facility, and underscores the importance of wearing surgical masks to control a pertussis outbreak.